Exposure To Ionizing Radiation Ebooks Catalog

How To Beat Electrical Sensitivity

This ebook is the complete guide to learning about electrical sensitivity and how to prevent getting it in your life. You will learn what electrical sensitivity is, and what causes it. Once you have started learning about it you will learn how to get rid of it and protect yourself from the dangers of electrical sensitivity. You will also learn how to heal yourself. This book is the product of careful research by the scientific and medical communities into the dangers and preventative measures of electrical sensitivity. ES is one of the most under-diagnosed conditions in the world right now, and this ebook is designed to education people as to how it works and how to prevent it. Do not let it take hold of your family; take control and prevent it now! Do not let yourself get any more hurt; learn about this condition and fight it! Read more...

How To Beat Electrical Sensitivity Summary


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Author: Lloyd Burrell
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The author presents a well detailed summery of the major headings. As a professional in this field, I must say that the points shared in this book are precise.

This ebook does what it says, and you can read all the claims at his official website. I highly recommend getting this book.

Ionizing Radiation Induced Apoptosis

It is well established that a principal mechanism of cell death following ionizing radiation damage involves necrosis.6,7 More recently, radiation research has also focused on apopto-sis as an alternative cell death mechanism following ionizing radiation.6,7 Apoptosis is an active, energy-dependent process in which the cell participates in its own destruction (i.e., programmed cell death).28 Apoptosis is characterized morphologically by cell shrinkage, cell membrane blebbing, chro-matin condensation, and finally by fragmentation into apoptotic bodies. The molecular sequence or cascade of apo-ptosis involves the early release of cytochrome C from mitochondria, activation of an apoptotic protease-activating factor (Apaf-1), activation of caspase 9, and subsequent cleavage of downstream (effector) caspases in a self-amplifying cascade. The apoptotic cascade degrades several essential cellular proteins including b-actin, laminin, and polyadenosine 5'-diphosphate-ribosyl polymerase...

Ionizing Radiation Roy E Albert MD

Ionizing radiation is undoubtedly one of the most intensely studied of all toxic agents. The impetus for understanding its manifold effects came from its extensive use since the beginning of the century in medical diagnosis and in treating cancer. With the development of atomic energy during World War II, the field expanded dramatically. Atomic energy became one of the country's largest industries. The potential health hazards from occupational and environmental sources of radiation became an important area for research it spawned a new field in the post-World War II era of measurement and control called health physics.

Protecting the staff from radiation exposure

Ionizing radiation is used in medicine for both imaging and therapeutics. When a radioactive isotope decays, a particles (two protons and two neutrons) or b particles (electrons) may be released. In addition, g radiation may be emitted. X-rays, like g-rays, are high-frequency electromagnetic radiation however, they are produced differently, being emitted when a beam of electrons is accelerated from a cathode to strike an anode, which is usually made of tungsten. The energy from these sources of ionizing radiation is initially dissipated in tissues by the displacement of electrons, thus producing chemically reactive ions. Therefore they may all cause tissue damage and chromosome changes, particularly in dividing cells. Exposure to all forms of radiation should be kept to a minimum. Non-ionizing radiation from the lower-frequency range of the electromagnetic spectrum includes ultraviolet (UV) light (wavelength, 10-400 nm). Wavelengths below 200 nm do not pose a hazard as they are...

Repair of Ionizing Radiation Damage Cellular and Molecular Mechanisms

As mentioned, ionizing radiation can cause a variety of lesions through direct interactions with DNA or, more commonly, through damage induced in adjacent water molecules within a cell or adjacent cells. These damages to DNA include damage to the deoxyribose backbone, base damage, single-strand breaks (SSBs), and double-strand breaks (DSBs).4 Because exposure to ionizing radiation was inevitable during evolution, human cells have developed multiple repair pathways to handle the diverse types of DNA damage created by ionizing radiation.5 Understanding these complex and sometimes redundant repair pathways in human cells has been a major focus in radiation biology during the past 10 to 15 years that will continue in the future.10 These studies on radiation repair pathways also have many links to ionizing radiation effects on the cell cycle, which is discussed later in this chapter. Repair of ionizing radiation-induced base damage involves a sequence of biochemical processes termed base...

Ionizing Radiation Chemicals And Cancer

The carcinogenic potential of ionizing radiation was soon recognized after Roentgen's discovery of x-rays in December 1895. The first report of leukemia in five radiation workers dates back to 1911.43 (Marie Curie and her daughter, Irene, are both thought to have died from complications of radiation-induced leukemia.) Follow-up studies on atomic bomb survivors in Hiroshima and Nagasaki have confirmed that ionizing radiation is a universal carcinogen in that it induces tumors in most tissues of most species at all ages, including the fetus. The universal nature of radiation as a carcinogen is based on its ability to penetrate cells and deposit energy within them in a random manner, unaffected by the usual cellular barriers presented to chemical agents. As a consequence, all cells of the body are susceptible to ionizing radiation, and the amount of damage will depend on the physical parameters that determine the radiation dose received by a particular cell or tissue. Radiation can...

Ionizing Radiation Effects on the Cell Cycle

Ionizing Radiation Cell Cycle

It has been known for several decades that ionizing radiation leads to a prolongation of the cell cycle and can result in an arrest in the G1, G2, and S phases.7,19,20 Because ionizing radiation causes a variety of DNA damage, it was initially inferred that these cell-cycle arrests (now called checkpoints) were essential for the repair of these different types of DNA damage. However, over the past 10 to 15 years, the biology of the cell cycle has become better understood as a complex but finely regulated process involving many factors, particularly the cyclins and cyclin-dependent kinases (CDKs).19 Progression through the cell cycle is promoted by a number of CDKs that are complexed with specific regulatory proteins called The arrest of cells at the G1 checkpoint following ionizing radiation damage is best understood at the present time. The retinoblastoma tumor suppressor gene product (Rb) governs the G1-S phase transition.21 In its active state, Rb is hypophosphorylated and forms an...

Radiation Injuries Ionizing Radiation

Etiology Ionizing radiation (neutron, or gamma x-ray radiation) have high energy that can cause ionization and formation of radicals in cellular tissue. Penetration depth in the eye varies with the type of radiation, i.e., the wavelength, resulting in characteristic types of tissue damage (Fig. 18.13). This tissue damage always manifests itself after a latency period, often only after a period of years (see also Symptoms and clinical picture). Common sites include the lens (radiation cataract) and retina (radiation retinopathy). This tissue damage is usually the result of tumor irradiation in the eye or nasopharynx. Radiation disorders have been observed in patients from Hiroshima and Nagasaki and, more recently, in Chernobyl.

Potential biological effects of exposure to magnetic fields

The potential biological effects of MRS and MRSI are related to exposure to static, gradient and radiofrequency electromagnetic fields. Each of these can represent a possible health risk at high levels of exposure, although there is much uncertainty and controversy about the extent to which low-level exposures are harmful 1 . It has been argued that there is a small value of magnetic susceptibility of human tissues. However, there have been no replicated studies demonstrating a health hazard associated with magnetic field exposure, nor with cumulative exposure to these fields 2 .

Ionizing Radiation Interaction with Oxygen

It has long been recognized that cellular and tissue oxygenation is a major determinant of radiosensitivity.31,32 For several decades, oxygen was considered to be a radiation dose modifier as in vitro in vivo radiobiology data suggested that the oxygen enhancement ratio (OER) is 2.5-3.0 for low-LET radiation (X-rays, photons) and 1.5-2.0 for intermediate-LET radiation (protons). More recently, experimental and limited clinical data suggest that the OER for both low- and intermediate-LET radiation are lower at lower doses typically used daily in treating human cancers. Although the underlying mechanism of the oxygen-modifying effect is not exactly known, the leading model suggests that cellular oxygen acts as a radiosensitizer by forming radicals such as peroxides in DNA, resulting in a fixation or persistence of ionizing radiation (IR) damage.

Ionizing Radiation

In addition to benzene, exposure to ionizing radiation is also considered an established risk factor for adult acute leukemia. Much of what we have learned about the effects of radiation on hematopoietic neoplasms comes from studies of atomic bomb survivors. In an evaluation of leukemia mortality among survivors of Nagasaki and Hiroshima, the highest risk for AML appears to be among individuals exposed to radiation aged 45 years or greater, while ALL risk appears higher in those exposed under the age of 30.134,135 Occupational exposure to ionizing radiation has also been explored with radium workers and early cohorts of radiologists demonstrating elevated risks of leukemia.108 Moreover, patients irradiated for benign conditions including menorrhagia, peptic ulcer, or ankylosing spondylitis have been reported to be at an increased risk of leukemia.136-139 Leukemia risk following radiation fallout from nuclear plants is less conclusive. Earlier studies reported excess risk among nuclear...

Interventional Therapies

In RF ablation coagulation is achieved with induction from all electromagnetic energy sources less than 900 kHz. Most of the currently available devices function in their range between 375 and 500 kHz and are either monopolar or bipolar systems. Many electrode variations are currently available, which will be described in more detail in the technical and clinical parts of the book (multi-tined, expandable electrodes, internally cooled electrodes, and perfusion electrodes). For each RF application the algorithm used should be differentiated (ramped energy deposition or impedance regulated and the model number of the generator). Other parameters are the use of monopolar bipolar systems, the duration of ablation and the amount of energy applied (in current and or watts). Additional adjuvant therapies are used such as the concomitant percutaneous instillation of sodium chloride solutions to alter the electrical and thermal conductivity during ablation. Hence, the specific details of the...

Chronic Myeloid Leukemia

With the advent of cytotoxic drugs, the role of ionizing radiation in the treatment of CML diminished in the 1960s, before which time it had been the treatment of choice. It became restricted to the treatment of splenomegaly in patients with special features, such as women who are pregnant at the time of diag-nosis.50 The major place for ionizing radiation in the modern treatment of CML consists of myeloablation and immunosup-pression prior to autologous or allogeneic transplantation.

The Brain and Related Structures in CT

The advantages of CT are 1) it is rapidly done, which is especially important in trauma 2) it clearly shows acute and subacute hemorrhages into the meningeal spaces and brain 3) it shows bone (and skull fractures) to advantage and 4) it is less expensive than MRI. The disadvantages of CT are 1) it does not clearly show acute or subacute infarcts or ischemia, or brain edema 2) it does not clearly differentiate white from grey matter within the brain nearly as well as MRI and 3) it exposes the patient to ionizing radiation.

Advances in Computed Tomography

Computed tomography (CT) is the mainstay of cancer imaging outside of the central nervous system. Advances in multidetector CT (MDCT) technology have had a profound impact on its diagnostic capabilities. Such techniques as multiphase, single breath-hold imaging, CT angiography (CTA), volume rendering and virtual colonography owe their success to the development of multidetector arrays with continuously moving gantries. However, to achieve these advantages without incurring the penalty of increased radiation exposure, care must be exercised in selecting the optimum combination of slice thickness, X-ray beam collimation, and table speed.

Pyrimidine Antagonists

The initial rate-limiting step in degradation involves the enzyme dihydropyrimidine dehydrogenase (DPD), which is widely expressed in tissues including the liver, GI mucosa, leukocytes, and kidney. Thus, 5-FU is poorly absorbed orally. Because of its size, the liver has the highest total content of DPD and is a major site of 5-FU metabolism. DPD is subject to genetic polymorphisms, with 8- to 21-fold intersubject variability. Those with low DPD activity are susceptible to severe toxicity. Greater first-pass effect (more than 90 ) through the liver results in lower systemic drug levels (and, consequently, fewer side effects) with FUDR, making it the preferred agent for hepatic arterial infusion (HAI). When administered with IV bolus schedules, FUDR is catabolized to the predominant 5-FU form.86 Several important interactions between 5-FU and other agents have been described. Leucovorin expands the pool of reduced folates to enhance the inhibition of TS. Methotrexate...

Internal and External Proteotoxic Stresses in Mammalian Cells

It is important to note that purely genotoxic stresses such as ionizing radiation do not lead to the elevated expression of heat shock proteins (Anderson et al. 1988) and inversely, that the transiently elevated expression of heat shock proteins by, for example, heat stress does not affect the sensitivity to ionizing radiation, which is particularly relevant to the discussion on the role of Hsp in the process of apoptosis (Sect. 9).

Radioactive substances

Radioactive substances When planning an experiment that involves the use of radioactivity, consider the physico-chemical properties of the isotope (half-life, emission type, and energy), the chemical form of the radioactivity, its radioactive concentration (specific activity), total amount, and its chemical concentration. Order and use only as much as needed. Always wear appropriate gloves, lab coat, and safety goggles when handling radioactive material. X-rays and gamma rays are electromagnetic waves of very short wavelengths either generated by technical devices or emitted by radioactive materials. They might be emitted isotropically from the source or may be focused into a beam. Their potential dangers depend on the time period of exposure, the intensity experienced, and the wavelengths used. Be aware that appropriate shielding is usually made of lead or other similar material. The thickness of the shielding is determined by the energy(s) of the X-rays or gamma rays. Consult the...

Magnetic Resonance Imaging MRI

The advantages of MRI over CT scanning are clear. MRI has better tissue resolution and uses non-ionizing radiation attractive from a radiation safety point of view. However, MRI scanning comes with its own potential safety hazards. Any person entering the MRI scanner room must be screened for any metallic objects either on their person, or within the body itself. Some metals have magnetic properties (e.g. recall a school science experiment with iron filings and a bar magnet) and may be strongly attracted to the very strong magnetic field in the MRI scanner. They will be propelled towards the center of the MRI scanner at breakneck speeds and could injure anyone in the vicinity of the magnet's bore. Similarly, any devices that have been surgically implanted in the body, or accidentally embedded e.g. schrapnel, that are themselves magnetic may begin to move within the body and cause internal injury. Additionally, there is the problem of the strong magnetic field erasing credit cards,...

Response to 90o radiofrequency pulse Resonance and relaxation

Equilibrium state with a net magnetization vector M is achieved within seconds. This can be disturbed and shifted by an externally applied pulse of electromagnetic waves at the Larmor frequency. Only radio-frequency (RF) waves of precisely this frequency (energy) will transfer

Radiation Interactions with Biologic Materials

Ionizing radiation deposits energy as it trasverses various types of biologic materials or media (e.g., air, soft tissue, bone) within a human. The interaction of ionizing radiation with these biologies is a random process, with the frequency and density of energy deposition termed the linear energy transfer (LET). As human cells and tissues (as well as tumors) are principally considered to be dilute aqueous (water) solutions containing biomolecules, the localized but randomly distributed energy depositions from ionizing radiation can have either direct effects on important biomolecules such as DNA

Growth Factor Receptor Targeting for Radiosensitization

Two other approaches that attempt to target tumor growth and enhance tumor response to ionizing radiation involve targeting tumor oncogenes such as Ras78 and the nuclear transcription factor NF-KB.79 As no clinical data are available on these potential targeted therapies, the reader is referred to two recent reviews of the preclinical research and proposed clinical testing.78,79

Physics of Microwave Heating

Microwaves belong to the electromagnetic waves with wavelengths in the range of 30 cm (frequency 1 GHz) to 1 mm (300 GHz), meaning, therefore, that the microwaves have wavelengths longer than those of infrared light, but shorter than those of radio waves. The boundaries are, however, arbitrarily chosen and differ in various fields of science and engineering. Microwaves are used in many areas of modern technology, especially in the field of communication (cellular phones, wireless internet connections, satellite television). For medical uses specific frequencies between 915 mHz and 2.4 GHz have been designated so as not to interfere with communications in the aviation and military frequencies. Common MW ovens operate at approximately 2.45 GHz. As the water molecule exhibits an electric dipole moment, the electric field of the MW excites harmonic oscillations in the water as they try to align themselves with the alternating electric field, resulting in warming. Other molecules are...

Preoperative Evaluation Choice of Imaging Modality for Guidance

Flexibility in needle placement is virtually unlimited, and its real-time feedback as to the needle position is unmatched by any other modality. It is almost a platitude to mention its additional advantage of avoiding ionizing radiation. Naturally, it is not a suitable technique to target strictly intraosseous lesions, and as with any ultrasound procedure, operator expertise is fundamental to the success.

Side Effects And Dosimetric Considerations

Side effects of radiation synovectomy are related to local complications, which arise from para-articular injection and intra-articular infection (Table 6). They may also be related to radiation exposure during the normal treatment course such as a transient radiogenic synovitis, potential radiation damage to articular cartilage or subchondral bone, and irradiation of locoregional lymph nodes, liver, and spleen owing to extra-articular leakage of the radiocolloids.

Local Complications After Radiation Synovectomy

Radiation exposure and future malignancy Other risks associated with the procedure are allergic reactions to contrast medium and local anesthetics, hyperglycemia in diabetic patients and flush symptoms from steroids, thyreotoxicosis as a result of iodine-containing contrast medium, and thrombosis due to immobilization Patients should be advised to report any worsening or other uncommon changes in the treated joint, and the patient should be given a contact he can reach at any time

Evanescent Wave Fiber Optic Biosensors

When light is launched down a waveguide placed in contact with a lower refractive index material, if conditions are present to allow total internal reflection of this light, an electromagnetic component of the light extends out from the surface of the waveguide into the lower index medium. This electromagnetic field, the evanescent wave, has a limited penetration depth and can be used to specifically excite fluorophores bound to, or in close proximity to, the waveguide surface. Evanescent wave fiber optic biosensors have been developed utilizing the limited penetration depth of the evanescent wave to detect a variety of analytes. These sensors are able measure optical events at the fiber's surface with relatively little interference from the bulk solution. The ability of these instruments to detect analytes rapidly and specifically, even in the presence of complex sample matrices, has been demonstrated both under laboratory conditions and in the field.

Neuroprostheses For Motor Function

This can be done by direct percutaneous connection or via a radiofrequency (RF) transmission (see Chapter 6 for details). In the latter case, nothing crosses the skin except electromagnetic energy, reducing the likelihood of infection present with percutaneous connections and improving the convenience of donning and doffing over completely external systems. Implanting components of the system requires additional circuitry (RF transmitters and receivers) to complete the communication pathways and may increase the complexity of the design. In spite of the required surgery, implantable systems offer the advantages of placing the stimulating electrodes in close proximity to neural structures, greatly increasing the selectivity and efficiency of activation while simultaneously reducing the required current.

Magnetic Resonance Imaging

Many investigators consider magnetic resonance imaging (MR Table 10.3) the imaging modality of choice in the initial evaluation of NB (Siegel et al. 2002 Sofka et al. 1999). Magnetic resonance has distinct advantages over CT including (a) the absence of ionizing radiation, (b) the ability to evaluate neural foraminal and epidural involvement, and (c) the ability to detect bone marrow disease. In addition, MR is ideal for defining the precise extent of skeletal in

Radiation Safety Considerations For Personnel

So far, few data exist on radiation exposure to personnel. As all the commonly used radionuclides are 3 emitters and only Re-186 and Dy-165 have an additional g component, significant radiation exposure is only achieved during handling and application of the radiopharmaceuticals. Performing the radionuclide application under fluoroscopy results in an additional radiation exposure to the personnel. For a standard application of 10 GBq Dy-165, the finger doses for the applying physician and the technologist were 0.7 mSv and 0.3 mSv, respectively, while whole-body doses were reported to be 0.1 mSv for the technologist and 0.04 mSv for the physician (75). Liepe et al. (76) found that the highest radiation dose during radionuclide injection is received by the left index finger in right handers. The maximum received doses were 22.1, 1.8, and 0.8 mSv MBq for Y-90, Re-186, and Er-169, respectively. This translates into finger doses of 4 mSv per knee joint treated with 200 MBq of Y-90, about...

Limitations Of Multidetector Helical Computed Tomography

Other relative limitations of MHCT include the increased complexity of imaging protocols, the increased importance of proper timing for optimal enhancement in vascular studies, and the potential to increase the radiation dose, depending on the specific scanning parameters employed. With regard to radiation exposure, if MHCT is performed with equal slice thickness to single-detector CT, MHCT actually results in a slightly decreased dose to the patient due to better dose efficiency of the detector however, this advantage is lost or reversed if thinner slices are routinely employed with MHCT 6 . Importantly, preliminary investigations suggest that one may perform MHCT of the lungs with a ''low-dose'' technique for some clinical indications 20 . Future research in this area is necessary.

Mechanisms of Tumorigenesis

Similar to tumorigenesis in other tissues, development of meningiomas is likely to result from complex interactions between genes and environment. The etiological role of environmental factors in meningioma development has been suggested for ionizing radiation, diet, smoking, head trauma, and occupational exposures to carcinogenic substances. Of these factors, the evidence is convincing only for an association between ionizing radiation and meningiomas. Elevated risk of meningioma development was shown in studies involving patients who received a low-dose radiation therapy for childhood tinea capitis. Meningiomas were also found to occur years after any type of therapeutic cranial irradiation. Moreover, an increased incidence of meningiomas has been recently reported in survivors of atomic bomb explosions. Radiation-induced meningiomas are often aggressive or malignant. They are also

Percutaneous Needle Aspiration Conventional Imageguidance Techniques

Several investigators have reported the use of ultrasound to assist in thoracic biopsy 8,9,10 . Advantages of ultrasound include real-time imaging, portability, and lack of ionizing radiation. The development of high-resolution, high-frequency probes with dedicated biopsy ports has facilitated use of this technique. However, sonography is limited by attenuation of the beam as it traverses air-filled lung, obscuring nodules that are deep in the lung. Overall, less than 50 of lung masses are accessible to ultrasound guidance 6 . Ultrasound is best reserved for use in biopsy of pulmonary nodules that abut the pleural surface.

Abnormalities Of Thyroid Hormone Receptors In Thyroid Cancer

One possibility is that the Polish patients were from the post-Chernobyl population and that radiation exposure is a contributing factor to the high frequency of TR mutations. Indeed, five of the 16 Polish patients with mutated TRs were in their teens when the Chernobyl accident occurred. One of 16 patients received radiation treatment during her childhood because of another disease. The age of other patients ranged from 32-58 years old at the time of the Chernobyl accident (Monika Puzianowska-Kuznicka personal communication). The validation of this hypothesis would require a cohort study with a larger number of patients and a detailed knowledge of irradiation dose received by the patients.

Choice Of Imaging Modality

The size, location, and contents of the collection are important considerations when selecting the appropriate imaging modality for guidance. In general, ultrasound is most useful for drainage of large free-flowing fluid collections 23 . Ultrasound is the technique of choice because it lacks ionizing radiation, is portable, and allows real-time visualization of needle catheter placement. At times, a free-flowing collection may be less accessible with CT guidance because the fluid collection tends to move to a dependent position in the chest. In contrast, complex fluid collections and air often cannot be distinguished from underlying aerated lung parenchyma by ultrasound and may require CT guidance 24 . The location of the fluid collection may dictate the choice of modality. Structures that are located along the proposed route of catheter insertions such as internal mammary vessels or mediastinal structures may be easier to visualize and avoid with CT guidance. Patients whose condition...

Angiosarcoma ICDOcode91203

Primary angiosarcomas of the larynx are exceedingly rare, with only a few well-documented reports. Despite the fact that nearly 50 of all angiosarcomas occur in the skin and superficial soft tissues of the head and neck, angiosarco-ma accounts for less than 0.1 of all head and neck malignancies. Laryngeal angiosarcoma is twice as frequent in men with a mean age at presentation in the 7th decade of life. Symptoms are non-specific previous radiation exposure is frequently noted. The supraglottis is affected more frequently, specifically the epiglottis, where an increasing size is associated with a worse clinical outcome. Tumours demonstrate the typical histomorphologic features of angiosarco-ma in other soft tissue sites. Tumour cells are consistently positive with Factor VIII-related antigen, CD34, and CD31. Contact ulcer, haemangioma, acantho-lytic squamous cell carcinoma and mucosal malignant melanoma are the principle differential diagnostic considerations. Surgical excision is the...

Use of Sex Steroid Metabolites as Therapeutic Regimens After Trauma Hemorrhage

Similar to DHEA, recent studies have evaluated the role of another metabolite, adiol, in altered cardiac and hepatocellular function after trauma-hemorrhage (Shimizu et al., 2004,2005). Adiol, one of the metabolites of DHEA, has been reported to have greater protective effects than DHEA against lethal bacterial infections and endotoxin shock. Furthermore, adiol has also been reported to produce protective effects after ionizing radiation in mice (Whitnall et al., 2002). Recently, studies from our laboratory have shown that adiol administration after trauma-hemorrhage improves cardiac and hepatic function in male animals. Additional recent findings from our laboratory suggested that adiol ameliorates hepatic functions via activation of PPAR-y (unpublished observations). However, whether adiol affects the cardiac hepatic function either directly or via modulation of sex hormones remains to be established.

Advantages and Limitations

Like all optical biosensors, fiber optic sensors have several advantages over sensors that utilize other signal transduction methods. No direct electrical connection to the transduction system is required. Therefore, optical sensors are immune to many interfering electrochemical and electromagnetic effects that plague sensors based on electrochemical transduction, such as electromagnetic radiation, corona discharge, radiofrequency interferences, corrosion, shock vibrations, and harmonic induction. Furthermore, the lack of requirement for radiolabels or hazardous organic materials for sample preparation or signal generation (such as benzene and other organic solvents) render optical sensors more user-friendly than other methods that do. In addition, over the years, with the increased availability and quality of small-scale light sources, the size and price of optical biosensors have continued to decrease.

Detection of DNA doublestrand breaks by the comet assay

The alkaline comet assay, described earlier, which includes incubation at high pH before and during electrophoresis, is the most common variant now employed. The alkaline comet assay identifies both single- and doublestrand breaks because the two strands of DNA are uncoiled at the breaks by alkaline denaturation. The idea came about that if the assay is performed in neutral buffers (pH 10), it detects only double-strand breaks because the DNA is not unwound. However, it now seems likely that both single- and double-strand breaks are identified by the comet assay at neutral pH (Collins et al., 1997 Olive et al., 1991). The reasoning is as follows. Treatment of cells with detergents and or high NaCl removes membranes, cytoplasm, and nucleoplasm and disrupts nucleosomes (histones are solubilized by high salt or ionic detergents, such as SDS). The nucleoid that is left consists of nuclear matrix and DNA that is negatively supercoiled consequent to the turns that the double helix had made...

Structural genes and enzymes

A total of 21 of these mutants have been identified, resulting from either chemical mutagenesis with EMS, or ionizing radiation (X-ray or fast neutrons). This includes 19 tt mutants, and two transparent testa glabra (ttg) mutants, which have pale seeds but also lack trichomes (leaf hairs) (reviewed by Winkel-Shirley, 2001). The absence of flavonoids in the seed coat reduces seed dormancy, and some of the tt mutants were actually identified based on their reduced dormancy, as opposed to the seed coat color.

Each Photon of Light Has a Defined Amount of Energy

Quantum mechanics established that light, a form of electromagnetic radiation, has properties of both waves and particles. When light interacts with matter, it behaves as discrete packets of energy (quanta) called photons. The energy of a photon, e, is proportional to the frequency of the light wave e hy, where h is Planck's constant (1.58 X 10 34 cal-s, or 6.63 X 10 34 J-s) and y is the frequency of the light wave. It is customary in biology to refer to the wavelength of the light wave, X, rather than to its frequency y. The two are related by the simple equation y c X, where c is the velocity of light (3 X 1010 cm s in a vacuum). Note that photons of shorter wavelength have higher energies.

Total internal reflection

Where nj(2) is the refractive index of the first (second) medium, and n1 n2. In the lower refractive index medium, there is an exponentially decaying electromagnetic field called the ''evanescent wave''. The evanescent wave excites fluorescent molecules within about 150 nm of the surface, and its intensity at the surface can be higher than the intensity of the incident beam (Ambrose et al, 1999).

Double Strand Repair in Eukaryotes

Double-strand breaks may be caused by ionizing radiation and certain chemical mutagens. They may also be left behind when some transposable elements excise themselves and move (see Ch. 15). Both yeast and mammalian cells have a similar system for repairing double-strand breaks by a process known as non-homologous end joining (Fig. 14.26). First the two Ku proteins bind, one on either side of the break. DNA-dependent protein kinase (DNA-PK), which is attached to the Ku complex, then activates the XRCC4 protein, which in turn directs DNA ligase IV to repair the break.

Side Effects of Radiation

Organ dysfunction may result from radiation exposure if tolerance doses are exceeded (see Chap. 18). Standard whole-organ tolerance doses are as follows heart 15 Gy lungs 15 Gy kidneys 18 Gy liver 30 Gy bowel 30 Gy ovaries 10 Gy and testes 2 Gy. These doses are only general guidelines. Young children who are heavily pretreated with chemotherapy or who have had surgery may experience organ dysfunction at lower doses. Neurocognitive dysfunction and endocrine abnormalities as a result of brain irradiation are dependent upon the child's age, radiation dose, and volume of brain exposed. These issues are important to consider when treating skull and orbital lesions. Cataracts are common side effects of radiotherapy and thus doses to the lens should be minimized when treating the orbit. Most children will not have permanent alopecia after doses of 21 Gy or less, but a small percentage may have permanent thinning. Doses exceeding 21 Gy do pose the risk of permanent epilation in the...

Verification of Dose Delivery

Verification of the dose delivered to a patient presents a difficult challenge. As mentioned previously, predicted dose can be calculated with mathematical models that take into account a number of patient and radiation-beam variables. Techniques exist for measuring radiation dose actually delivered to a point on the body surface or in the body cavity, but are impractical for daily use. These include diodes and thermoluminescence dosimeters (TLDs) (33). TLDs are crystalline solids that trap electrons in an excited state after exposure to ionizing radiation. Heating of TLDs following exposure to radiation, results in a luminescence that can be translated to a radiation dose.

Stress Hormesis and Lifespan in C elegans

High doses of ionizing radiation reduce the lifespan of C. elegans, but low doses induce moderate lifespan extensions (4). We reproduced this result (S. Honda, Y. Honda, and S. Suzuki, unpublished observation) but Cypser and Johnson (7) found no lifespan extension by low-dose ionizing radiation as well as UV. These hormetic effects may be weak and occasional.

Cancer Treatment Modalities

Radiation and chemotherapy are treatments used to decrease tumor burden. The primary impact of radiation on the cell is a result of DNA damage, which activates p53 for G1 cell cycle arrest to allow for DNA repair, or the induction of apoptosis. It is known that chemotherapeutic agents induce p53-dependent cell cycle arrest, and it has been suggested that anticancer agents induce p53-mediated apoptosis.71 Although this may explain, in part, the resistance seen in some cancers with mutated p53 gene, it provides no insight as to why such treatment modalities are used to successfully treat tumors. Recently, a hypothesis has emerged that implicates intact cell cycle checkpoints involving cell cycle arrest as critical mediators of the response to chemotherapy and radiation. The p21 gene is transcriptionally activated by p53, and is responsible for the G1 cell cycle arrest following DNA damage. It has been shown that cancer cells with a defective p21 response as a result of deletion or p53...

Electrical Stimulation

- Electromagnetic stimulation by inductive coupling (IC) uses magnetic fields (noninvasive method). This technique, developed by Bassett et al. 9 , is based on the action of pulsed electromagnetic fields produced by external devices that generate a current of 20 mV and about 10 A cm2 in the tissues. Bassett et al. 9 reported a success rate of 87 in the management of nonunions.

Lightscattering Methods

Young's observation that the maxima and minima in a shadow behind an obstacle were caused by interference waves began the interest in the phenomenon of light scattering early in the nineteenth century. In the latter part of the nineteenth century, Maxwell developed the electromagnetic theory of light that linked electrical and optical phenomena. Lord Rayleigh used the new theory of electromagnetic radiation to investigate the scattering of white light by small particles. He formulated an approximation applying to very small particles whose refractive index was small. In order for Rayleigh scattering to apply, the particles also must be small in comparison to the wavelength of the radiation. Rayleigh's approximation is valid for particles of diameter less than one-tenth the wavelength of the incident light. This restriction assumes that the particle has a uniform internal field when the wave passes through, resulting in only one scattering center.

Ultrasoundguided Injections

Certain articular compartments are amenable to ultrasound-guided anesthetic injections. This technique is especially useful in satellite imaging centers or clinical settings where fluoroscopy units are unavailable. It is also cost effective because iodinated contrast material is not needed. In addition, the lack of ionizing radiation with sonographic guidance is an added benefit.

Scanning of the Thyroid

Radionuclide imaging of the thyroid is a direct extension of the clinical examination. It is important for the nuclear physician to be familiar with the setting in which the examination is being requested. Patients may be self-medicating with vitamins, kelp or other substances containing iodine and it is recommended to defer the examination for several weeks after discontinuation of these substances (Table 1). Clinical examination of the patient while under the camera allows correlation of palpable features with those of the scan. This ought always to be done by the physician who will report the examination and who should be aware of the presenting complaint, the relevant clinical history and laboratory data. A positive family history will increase the pre-test likelihood for multinodular goitre and Graves's disease. A complaint of pain predisposes toward thyroiditis. A history of radiation exposure with a symptomatic mass increases the probability of a malignancy.

Data Acquisition Image Reconstruction And Evaluation

One important improvement in PET technology is the development of combined PET CT systems. These systems are especially helpful as detailed morphological information is provided by high resolution CT scans. Furthermore, it has been shown that close correlation of PET and CT images is required to achieve optimal diagnoses. It has been repeatedly stated that the use of PET CT systems decreases the number of equivocal findings, even for experienced readers. According to our own experience, soft fusion'' of CT and PET images using dedicated fusion software is helpful in many cases (Fig. 5). Hard fusion'' using a dedicated PET CT scanner is generally easier, but demands an additional CT study and therefore adds radiation exposure for patients. Currently PET CT systems are being used for radiation treatment planning and in the future, the combination of PET and MRI may be even more helpful for functional morphological correlations.

Table 3 Classification of thyroid cancer

In the United States, the National Cancer Institute estimated that radiation exposure of Americans from weapons testing fallout may have been responsible for 7,000-70,000 thyroid cancers. This estimation assumes that the linear, no threshold hypothesis holds at the doses and dose rates in question. The question then arises whether the diagnostic use of x-rays and isotopes also contributes to the incidence of thyroid cancers. It appears, from the Swedish Cancer Registry, that patients who underwent 131I imaging in the past do not have an increased incidence of malignancy compared to those who had similar radiation exposures from x-rays. The difference has been attributed to difference in dose rates.

Environmental Factors

The effect of radiation exposure is controversial. Although, Annegers et al. (27) reported an increase in relative risk by 1.8 for women exposed to radiation, others have noted no difference (58). The effect of viral infection on ovarian cancer risk is also controversial. Both rubella and influenza have been noted to play a role (9) and mumps has been the focus of more attention. Some investigators have noted mumps infection to exert a protective effect (64), whereas others have described a harmful effect (65,66). On one hand, authors have speculated that women exposed to mumps are more likely to be born into larger families with more children, and in turn, produce more children themselves, thereby lowering their risk for ovarian cancer (46,67). On the other hand, others have suggested that patients with subclinical mumps infection may suffer early ovarian failure, with associated elevation of gonadotropin levels, which may stimulate ovarian epithelial growth, leading to an elevated...

Model Reaction for Methyl Coenzyme M Reduction with Coenzyme B to Methane

For completeness, two other reports on models for the in vivo activity of coenzyme F430 are mentioned here Drain et al. 99 reported that methyl-coenzyme M is converted to methane using the nickel macrocyclic complex Ni(II) in aqueous solution. During the process also O2 was formed and the process was not stimulated by reductants. Reinvestigation of this reaction revealed, however, that it was catalyzed by an impurity present in the technical grade tetraethylenepentamine rather than by the nickel complex 100 . The second report is by Zilbermann et al. 101 who described that methyl-coenzyme M is reduced by monovalent macrocyclic nickel complexes at pH 9.4 to methane in a 10 yield involving methyl free radicals as intermediate. Reduction of the Ni(II) complex to the Ni(I) complex was achieved by irradiating He saturated solutions in 0.01 M sodium formate with ionizing radiation. The preliminary communication was not followed up by a more detailed investigation.

Hereditary Breast Ovarian Cancer

It is estimated that approximately 1 of the general population may be heterozygous carriers of the mutated gene, ataxia telangiectasia-mutated (ATM), which has been localized to chromosome 11q22-23.67 The ATM gene encodes for a member of the phosphatidylinositol-3-kinase-like enzymes that are involved in cell-cycle control, meiotic recombination, telomere length monitoring, and DNA damage response pathways. AT cells are sensitive to ionizing radiation and radiomimetic drugs and lack cell-cycle regulatory properties after exposure to radiation.68 In vitro studies of AT carrier-derived lymphoblastoid cell lines have demonstrated defective control of apoptosis and mitotic spindle checkpoint control.69 Several epidemiologic studies have suggested a statistically increased risk of breast cancer among female heterozygote carriers, with estimated relative risks ranging from 3.9 to 5.1.70,71 ATM gene mutations associated with cancer in heterozygote carriers tend to be...

MR diagnostics in colorectal cancer

The potential advantages of MRI in avoiding exposure to ionizing radiation, plus the capability of multi-planar imaging, superior soft-tissue contrast and higher sensitivity to IV contrast are underscored by Oto 12 , Saar et al. 9 , and Luboldt and Morrin 38 . The disadvantages of MRC include lower spatial resolution, higher susceptibility to motion artefacts, as well as time and availability considerations 38 . Overall, virtual MRC would be an acceptable alternative to patients for screening compared to the currently available diagnostic tests such as double barium enema, colonoscopy or rectosigmoidoscopy, which either are associated with substantial discomfort, require sedation or entail exposure to ionizing radiation. Luboldt et al. 36 conclude the performance of MR colonography, as currently implemented, for the detection of masses that exceed 10 mm in diameter warrants further consideration of this technique as a potent option in the diagnostic arsenal for colorectal mass...

The Electron Microscope

A beam of electrons has a much smaller wavelength than visible light and so can distinguish detail far beyond the limits of resolution by light. Electron beams may be focused like visible light except that the lenses used for electron beams are not physical (glass absorbs electrons) but electromagnetic fields that alter the direction in which the electrons move. Using an electron microscope allows visualization of the layers of the bacterial cell wall and of the folded-up bacterial chromosome, which appears as a light patch against a dark background. When an electron beam is fired through a sample, materials that absorb electrons more efficiently appear darker. Because electrons are easily absorbed, even by air, an electron beam must be used inside a vacuum chamber and the sample must be sliced extremely thin (Fig. 21.26).

Irradiation 2231 Introduction

Studies on the effect of ionizing radiation upon living organisms started after the discoveries of X-rays in 1895 and radioactivity in 1896. The first patent for the use of irradiation as a food processing technology was filed in 1905, but sustained effort to use radiation to preserve foods did not begin until the end of World War II. The first commercial use of food irradiation occurred Typical ionizing radiation facilities use either gamma rays from the radioactive isotopes 60Co or 137Cs or electron beams as well as X-rays generated in electron accelerators 40 . Strict safety measures are required for gamma ray facilities due to continuous emission from 60Co and 137Cs, such as use of thick concrete walls to construct the irradiation chamber. In contrast, electron accelerators, as shown in Figure 22.2, have few leakage problems because they produce no high-energy electrons when not in use. As recommended by a joint FAO IAEA WHO expert committee on food irradiation (JECFI) in 1980,...

Use of Nanotechnology to Produce Amyloid Inhibitors

On the basis of the binding properties of the P-sheet breaker iAp5p and applying nanotechnology techniques, Kogan et al. (2006) designed a new approach to inhibit Ap aggregation (Fig. 1). The strategy was to conjugate gold nanoparticles (AuNP) with iAp5p in order for the particles to bind fib-rillar AP. Metallic nanoparticles can be induced to release localized heat after irradiation with low gigahertz electromagnetic fields. The local heat delivered by the nanoparticles selectively attached to the amyloid plaques can be used as a molecular surgery to denature and dissolve the protein aggregates (Fig. 1). AuNP were chosen because of their nanometric size, biocompatibil-ity, high electron density, and high (metallic) electron mobility. Ten-nanometer particles were used because they are small enough to penetrate the cell membrane, can survive harsh endosomal lysosomal processes, and are able to carry targeting peptides (Penn, He, & Natan, 2003).

Magnetic Resonance Imaging Techniques for the Assessment of Pulmonary Emboli

However, disadvantages of CT include the need for large intravenous injections of potentially nephrotoxic contrast medium and exposure to ionizing radiation 10 . Although CT has already gained wide acceptance as the primary cross-sectional technique to evaluate PE, many patients cannot have a CT examination because of an allergy to iodinated contrast media or severe renal insufficiency. These are not, however, contraindications to magnetic resonance imaging (MRI) evaluation.

Radiation Safety and Handling of Radiopharmaceuticals

These written protocols are extremely important. Radiation safety must be taken seriously. Every imaging facility should have a radiation safety officer and written policies on the receipt and storage of radioisotopes radiopharmaceuticals, proper preparation and calibration of radiopharmaceuticals, proper administration of radiopharmaceuticals, disposal of the radioactive trash, and how to handle spills of radiotracer. The policies should also discuss the proper use and quality control of radiation safety equipment and techniques to reduce technologist radiation exposure.

Magnetic Resonance Spectroscopy in Cancer

Agnetic resonance spectroscopy (MRS) evaluates in situ biochemistry by detecting signals from chemical compounds other than water. Proton or hydrogen spectroscopy is most commonly employed because it produces the strongest MRS signal and requires no modification of conventional high field MRI units. However, only a limited number of low molecular weight molecules with characteristic resonance properties can be detected with MRS. Among the most important in cancer are choline (cell membrane turnover), N-acetylaspartate (reduced in brain tumors), mobile lipids (reduced in breast cancer), and citrate (reduced in prostate cancer). Studies have shown MRS can detect cancers by demonstrating elevations of choline and reductions in normal metabolites. MRS provides information not attainable with conventional MRI without exposure to radio-isotopes or ionizing radiation.

Miscellaneous Issues

Poeia was quoted in this reference as stating When a fully validated terminal sterilization method by steam, dry heat or ionizing radiation is used, parametric release, that is the release of a batch of sterilized items based on process data rather than on the basis of submitting a sample of the items for sterility testing, may be carried out, subject to the approval of the competent authority.

Reflexive And Learned Responses To Pathogens

An animal cannot always reflexively avoid or remove pathogens. Thus learning to avoid stimuli previously associated with pathogen exposure or illness is an important line of defence. An important example of this, conditioned taste aversion, was first studied by Garcia and colleagues 21 and is often referred to as the 'Garcia effect.' In a typical taste aversion experiment, thirsty animals are given the opportunity to drink a novel, highly palatable solution (the conditioned stimulus, CS). Following consumption, animals are exposed to an illness-inducing agent (the unconditioned stimulus, US) early experiments used radiation exposure to induce illness, but numerous other treatments (e.g., lithium chloride) have been used for this purpose. Once the association between the illness and the novel tasting solution has been made, animals avoid the solution. A taste aversion can be produced with a single flavour-illness pairing, and even if there is a lengthy delay (e.g., many hours) between...

Step 5 The Phenomenal Model of the Intentionality Relation

The last step consists in applying the transparency constraint to the internal representation of the relation between subject and perceptual object, to the relation between agent and goal. If, for instance, the phenomenal model of one's own perceptual states contains a transparent representation of their causal history, then inevitably convolved global states will result, the content of which can only be truthfully described by the system itself as (e.g.) I myself the content of a transparent self-model am now seeing this object the content of a transparent object representation , and I am seeing it with my own eyes'' the simple story about immediate sensory perception, which sufficed for the brain's evolutionary purposes . The phenomenal self is a virtual agent perceiving virtual objects in a virtual world. This agent doesn't know that it possesses a visual cortex, and it does not know what electromagnetic radiation is It just sees with its own eyes'' by, as it were, effortlessly...

Future Of Mrs In Oncology

Past trends suggest an increased use of MRS for the purpose of addressing clinical management problems in cancer patients, and also to further our understanding of the unique biochemistry and physiology of cancer. Two attributes of MRS provide compelling support for this assertion. First, MRS clearly provides information beyond that provided by other forms of MRI. MRI provides a vivid anatomic depiction as well as some physiological information (e.g., perfusion or oxygenation), while MRS provides complementary biochemical information. The ease with which MRS can be incorporated into an MRI study protocol therefore guarantees it an increased use even though the biochemical information provided by MRS is not fully understood in many cases. Many relevant studies have emphasized that MRS augments MRI and that the two techniques should be used in concert. Second, MRS provides one of the few means of assessing aspects of tissue biochemistry without exposure to radioisotopes or to ionizing...

Cellular Automata and Recursive Growth

When we stroll across the quadrangle on a university campus, we feel we move through unbroken space that smoothly connects our beginning and ending points and that time flows continuously without interruption during our walk. When we pour water from one container to another, it is a continuous stream of water that flows. Yet, we know that water, at one level, is composed of discrete molecules. And we know that organisms reproduce discretely each female produces an integer number of offspring or each asexually dividing cell results in exactly two cells. In the space and time scales of human movement, we are a distinct entity that moves, not an amorphous, diffuse, electromagnetic field. Moreover, our neurons fire at discrete intervals, with finite recovery periods, and, more or less, in an on-off manner that prevents our observing the world at arbitrarily small time intervals. In this way, our senses and perceptions are digital it is something else that makes us think reality is...

Patient Preparation And Adjuncts To Treatment

Patients should not eat solid foods or drink dairy products for at least two hours before and after treatment. Water is advised, however, to reduce radiation exposure to the genitourinary tract. Multivitamins should be discontinued seven days prior to treatment. Low iodine diets for about one week prior to RAI treatment have also been advocated, although this has not been convincingly shown to improve response when RAI is used for the treatment of hyperthyroidism. Written informed consent should be obtained at the time of treatment. Informed consent should include a review of the disease, the rationale for treatment, treatment alternatives, potential side effects and outcomes, and the need for follow-up, in addition to radiation precautions, which should be provided both verbally and in written form. Patients with GD should be counseled regarding the risks of ophthalmopathy. The prescribed activity should be verified in a dose calibrator and the patient's identity should be confirmed...

Background Suppression

A schematic representation of a typical confocal microscope setup is shown in Figure 16.1. In a confocal setup, a laser beam is focused down to the diffraction limit using an objective with a high numerical aperture. A pinhole positioned in the primary focal plane of the objective rejects all light except that originating from the focal point, thus restricting the probe volume to the close vicinity of the focal point. A typical probe volume in a confocal setup is estimated to be 1 fL. TPE is another scheme that has been employed to successfully confine the sample volume and reduce the background signal for SMD. In a two-photon scheme, the analyte molecules are excited by simultaneous absorption of two photons with a total energy corresponding to the excitation energy of the molecule. The reason for the superior ability of TPE to reduce background is twofold. First, the efficiency of TPE has a quadratic dependence on the laser intensity. As a result, only the immediate vicinity of the...

Magnetic resonance spectroscopy

When a material is placed in an external magnetic field, these 'spins' begin to tumble in a precession. This motion enables the nuclei to absorb and emit electromagnetic waves with a frequency in the MHz range, depending on the strength of the magnetic field and the type of isotope. While MR images are generated in the majority of cases from the signals of hydrogen nuclei (1H) in water, MR signals can also be obtained from various other stable isotopes, including phosphorus (31P), carbon (13C), fluorine (19F), sodium (23Na) and others. Magnetic resonance spectroscopy makes particular use of 1H, 13P and 31C. Depending on the local chemical environment, different atoms in a molecule resonate at slightly different frequencies, resulting in the so-called 'chemical shift'. This chemical shift is resolved in spectroscopic applications (NMR and MRS), however it is neglected in standard imaging. It is measured in relative units (parts per million, ppm), and...

Dna Damage And Molecular Alterations In Cancer

Interaction of DNA with physical agents, such as ionizing radiation (X-rays), can lead to single-strand or double-strand breaks through sission of phosphodiester bonds on one or both polynucleotide strands of the DNA molecule (47). Ultraviolet (UV) light can produce cyclobutane pyrimidine dimers between adjacent pyrimidine bases on the same DNA strand. Less frequently, UV light produces non-cyclobutane-type pyrimidine dimers or 6-4 photoproducts between adjacent nucleotides in TC, CC, and TT pyrimidine dimers. Other minor forms of DNA damage caused by UV light include strand breaks and crosslinks (47). Nucleotide base modifications can result from exposure of the DNA to various chemical agents, such as N-nitroso compounds and polycyclic aromatic hydrocarbons (47). Among the numerous sites in the chemical structure of the nucleotides subject to modification by alkylating chemicals, the N7 position of guanine and the N3 position of adenine are the most frequently altered. DNA damage can...

John A DAndrea1 John M Ziriax1 and Eleanor R Adair2

Abstract This chapter is a short review of literature that serves as the basis for current safe exposure recommendations by ICNIRP (International Commission on Non-Ionizing Radiation Protection, 1998) and the IEEE C95.1 (IEEE Standard for Safety Levels with Respect to Human Exposure to Radio Frequency Electromagnetic Fields, 3 kHz to 300 GHz, 2005) for exposure to radio frequency electromagnetic radiation (RF-EMF). Covered here are topics on dosimetry, thermoregulatory responses, behavioral responses, and how these have been used to derive safe exposure limits for humans to RF-EMF. Energy in this portion of the electromagnetic spectrum, 3 kHz-300 GHz, can be uniquely absorbed and is different from ionizing radiation both in dosimetry and effects. The deposition of thermalizing energy deep in the body by exposure to RF-EMF fields provides a unique exception to the energy flows normally encountered by humans. Behavioral effects of RF-EMF exposure range from detection to complete...

Surface Enhanced Raman Spectroscopy

SERS is another optical detection technique suited for single-molecule studies because of its trace analytical capabilities together with its high structural selectivity compared to other optical spectro-scopies 76-79 . Strong enhancement in Raman signals can be observed from molecules attached to nanometer-sized architectures such as silver and gold nanoparticles 76,79-83 . Several potential schemes to prepare these nanostructured SERS-active architectures are schematically illustrated in Figure 16.7. The significant increase in cross section in SERS has been associated primarily with the enhancement of the electromagnetic field surrounding small metal objects through the interaction with SPR, and the chemical enhancement due to specific interactions of the adsorbed molecule with the metal surface. SERS enhancement factors on the order of 1014 corresponding to effective SERS cross sections of about 10 16 cm2 molecule allow Raman detection of single molecules. A further increase of...

Larynx Cancer Relative Risk Cigarettes

Global Cancer Incidence

There is controversy regarding occupational asbestos exposure and increased risk for developing laryngeal SCC 247, 1255,1982,2484 . A recent review has not supported a causative role for asbestos exposure 283 . However, there is evidence supporting other occupational exposures and increased risk of laryn-geal SCC, such as polycyclic aromatic hydrocarbons, metal dust, cement dust, varnish, lacquer, etc 1608 . After adjustment for alcohol and tobacco consumption, the increased risk ranged from 1.8 for cement dust to 2.7 for polycyclic aromatic hydrocarbons. Significant associations are also found with ionizing radiation, diesel exhausts, sulphuric acid mists and mustard gas 1608,2821 .

Renal Calculi Upj

Small Right Rental Calculus

Renal colic affects 1 in 1500 pregnancies, usually during the second and third trimesters. Conservative treatment consisting of analgesia and hydration is effective in most patients, and the renal calculi pass spontaneously in 75 of patients (239). More aggressive therapy is required in patients with refractory pain, sepsis, renal insufficiency (particularly if there is a solitary kidney), and colic-induced preterm labor. Therapeutic interventions during pregnancy are restricted to drainage of the affected collecting system by either a ureteral stent placed in a retrograde fashion or a PCN. Ureteral stents can be placed with local anesthesia and are usually well tolerated during pregnancy (240,241). Endoluminal ultrasound has been used to place a ureteral stent (242), thus avoiding the potential risks of radiation exposure. If stent placement fails, PCN is performed.

Acquired Chromosomal Abnormalities

No harm to the organism, but others are responsible for diseases like cancer. Most cancers result from an accumulation of several mutations. Although some constitutional factors influence the development of cancer, environmental factors such as exposure to carcinogens and ionizing radiation, diet, and certain viruses and bacteria play a major role. Many mutations involved in tumorigenesis occur at the gene level and cannot be detected cytogenetically, but others involve the presence or absence of chromosomes or chromosomal rearrangements that are visible at the level of the light microscope.

Herbal Medicine For Uretrohydronephrosis

Endourologic Stone Removal

It would be justified if the question is raised as to whether there is any realistic application for MR urography in urolithiasis, apart from the limited value of MRI in acute stone disease. Especially in patients suffering from chronic or recurrent urolithiasis, MR urography is a potential alternative to CT for avoiding repeated radiation exposure (Figs. 11 and 13). In chronic nephrolithiasis resistant to treatment, MR urography provides detailed morphologic information about the complicated pelvicaliceal anatomy, which favors the formation of calculi and often leads to stone impaction (Fig. 13) (3,22). Unless there is an acute colic, the use of low-dose furosemide is actually not a problem in chronic stone disease. Prior to lithotripsy or endourologic stone removal, MR urography with multiplanar MIP images yields

Treatment Of Children With Hyperthyroidism

Although RAI is effective, the potential risks related to radiation exposure need to be carefully discussed with the parents or guardians of pediatric patients. Common concerns that may need to be addressed include genetic and oncogenic effects of administering radioactivity, and the potential for radiation exposure to others by young patients in whom proper hygiene may be difficult to maintain. With external radiation exposure, there is a known risk of thyroid cancer in children that may decrease with increasing age at exposure (62). Studies of radiation exposure related to fallout from nuclear weapon testing in the Marshall Islands and the Chernobyl disaster have also shown higher rates of thyroid cancer in children (63). However, less is known regarding the risk of thyroid cancer following the medical use of RAI in children, and a comprehensive study of thyroid and nonthyroid cancer risks in this setting has not been performed. At prescribed activities of 3.7-7.4 MBq (100-200 pCi)...

Review The Concepts

DNA-repair systems are responsible for maintaining ge-nomic fidelity in normal cells despite the high frequency with which mutational events occur. What type of DNA mutation is generated by (a) UV irradiation and (b) ionizing radiation Describe the system responsible for repairing each of these types of mutations in mammalian cells. Postulate why a loss of function in one or more DNA-repair systems typifies many cancers.

Management Recommendations

Nosocomial Infections Slight Sere

Bosniak recommends the first follow-up be obtained by dedicated renal CT at six months and then annually thereafter for five years if the patient is older than 50 years of age. Even longer follow-up might be considered in younger patients because of lack of data on these patients. Because of concerns with radiation exposure,

Angiogenesis in Skin Diseases

Squamous cell carcinoma (SCC), a malignant tumor of keratinocytes with destructive growth pattern and the capacity to metastasize, arises as a result of exogenous carcinogens such as chronic exposure to sunlight, ionizing radiation, or chemicals. The stroma of SCC is richly vascu-larized and SCC tumor cells strongly express VEGF. Whereas the inhibition of VEGFR-2 (flk-1) prevents SCC growth and invasion, experimental overexpression of VEGF in highly differentiated SCC cell lines promotes invasive-ness, tumor growth, and angiogenesis. These experimental data provide evidence for a critical function of VEGF in SCC progression, and they indicate that blockade of VEGF in patients might reduce the malignant progression of SCC. In contrast, only low levels of VEGF expression have been detected in basal cell carcinomas of the skin that are also richly vascularized. Preliminary evidence suggests that other angiogenic factors such as fibroblast growth factors and platelet-derived growth...

Antiparkinsonian Therapy And Hypersexuality

Sandyk18 reported on two men with PD and ED, ages 70 and 73, who experienced sexual arousal and nocturnal erections after receiving treatment for PD with transcra-nial administrations of AC-pulsed electromagnetic fields (EMFs) of 7.5 picotesla flux density. The first patient received EMF treatment for two consecutive days. He reported a decrease in parkinsonian symptoms after the first treatment and experienced sexual arousal and awakening during the night with several repetitive spontaneous erections lasting 15 to 20 min. During the second treatment, he experienced sexual arousal. The patient experienced nocturnal erections during the following three nights. The second patient had two successive EMF treatments for four days. This patient reported sexual arousal associated with nocturnal erection.

A25OH2D3 Analogs In The Treatment Of Cancer

Deltanoids can be effectively combined with ionizing radiation and chemo-therapeutic agents such as adriamycin to induce apoptosis in breast tumor models both in vitro and in vivo.82-86 While the primary response of breast tumor cells to deltanoids such as EB 1089 is growth inhibition, apoptosis has been observed in a fraction of the cell population. The possibility that the combination of deltanoids with radiation might promote cell death (i.e., through a differentiation stimulus plus DNA damage) was investigated by exposing both TP53 wild-type Treatment with EB 1089 was found to block the increase in p21waf1 cip1 levels induced by adriamycin and interfere with induction of MAP kinase activity by ionizing radiation. These effects may be related to the capacity of EB 1089 to promote secretion of insulin-like growth factor binding protein. Similarly, pretreatment with another deltanoid, ILX 23-7553, shifted the dose-response curve for clonogenic survival, increasing sensitivity to...

Radiationassociated Thyroid Tumors

Indeed, a number of experiments in rats have shown that after thyroid exposure to radiation, the risk of developing a thyroid tumor is increased when cell proliferation is stimulated (administration of goitrogens, high or low iodine diet, partial thyroidectomy, TSH stimulation) and decreased when cell proliferation is decreased (hypophysectomy, administration of L-thyroxine). In a recent study in rats, high and low iodine diet both increase proliferation, and both induced thyroid adenomas but no thyroid malignancies occurred. Thus both a mutagenic event (radiation exposure) and increased proliferation rate are needed for the occurrence of thyroid carcinoma (2). Activating mutations in the ras genes have been found in thyroid tumors from patients with a history of external irradiation, at a frequency similar to that observed in apparently spontaneous tumors (6). In contrast, in tumors that developed in children after the Chernobyl accident, ras point mutations were found in 25 of the...

Mitochondrial Dna Damage And Repair

ROS are produced continuously at a high rate as by-products of aerobic metabolism, including oxygen-free radicals, such as the superoxide radical anion as the primary product of one-electron dioxygen reduction nitric oxide and the derived peroxynitrite, the radical superoxide, singlet oxygen, and the strong non-radical oxidant H2O2, hydroxyl radicals (some are produced by radiation) (42). H2O2 can be reduced to the highly reactive hydroxyl radical OH- by a metal through the Fenton reaction or during exposure to ionizing radiation which can cause additional DNA damage. It induces at least eleven different base products whereas 35-55 of those alterations are expected to result in strong blocks to the polymerase (41). It is calculated that 1-4 of the oxygen reacting with the respiratory chain is incompletely reduced to ROS (24). Since mitochondria are the major producers of ROS, they are particularly susceptible to their attacks. Even ROS produced outside the mitochondria may damage...

Role Of Ebrt In Second Malignancies

Cyclophosphamide treatment, most of these patients have also received radiotherapy. The real risk of chemotherapy is difficult to determine. Hawkins and coworkers estimate a 26-fold risk of SMN development in Rb patients treated with radiation but no chemotherapy, and a 78-fold risk in patients who receive both radiation and chemotherapy.47 For bone sarcomas, the relative risks are significantly higher 174 times for Rb patients who receive no chemotherapy or radiotherapy, and 340 times and 771 times, respectively, in patients who receive radiation but no chemotherapy, and radiation with chemotherapy. The alkylating cytotoxic agents and ionizing radiation are known carcinogens. It is quite conceivable that these agents alone, or in combination, increase the frequency of somatic mutations needed to produce SMNs in Rb patients.50,67

Instrumental Diagnosis

From the radiological point of view, angio-CT scan and angio-MRI play a very important role because they offer undoubted advantages to traditional phlebography. With these techniques, sites formerly difficult to investigate can be visualized, reducing side effects thanks to the very low quantity of contrast medium employed and obtaining very good results in terms of sensitivity and specificity. The limitations of these techniques are related to costs and high radiation exposure of the angio-CT scan 4 .

Specific Industrial Occupations

Epidemiologic studies have also been performed to attempt to find occupations at high risk for developing PD. Fall et al. performed an occupation case control study and found an increased risk of PD in carpenters odds ratio (OR) 3.9 , cabinet makers (OR 11), and cleaners (OR 6.7) compared to a population-based control group.12 Tanner et al. performed a case control study (nonpopula-tion-based) of occupational exposures and PD in China and found that occupations involving industrial chemical plants (OR 2.39), printing plants (OR 2.40), and quarries (OR 4.50) were associated with a higher risk of PD.13 Unfortunately, no detailed occupational information was provided. A population-based survey of PD in British Columbia found an association between PD and working in an orchard (AOR 2.30) or planer mill (AOR 4.97).14 They hypothesized that industrial chemicals, including pesticides and herbicides, could be etiologic agents. Another nonpopulation-based case-control study in the same region...

Techniques And Modes Of Imaging The Upper Airway

Anatomic Radiology Oral Cavity

The list of upper airway imaging techniques includes cephalography (cephalometric radiography), nasopharyngoscopy, acoustic reflection, conventional and electron beam CT, three-dimensional CT, MRI volumetric MRI, and optical coherence tomography. Together, these imaging modalities have greatly improved our understanding of OSA however, each has its limitations. Fluoroscopy, an older imaging technique, involves significant radiation exposure and is time-consuming it has been replaced by newer imaging modalities that can also provide dynamic images with the capability to obtain more precise anatomic measurements. The ideal imaging technique would provide safe, accurate, and repetitive measurements in the supine position. Such a modality would allow for three-dimensional volumetric reconstructions of the upper airway and its

Drosophila as a Genetic Model System for Molecular Neurobiology

The entire genome of Drosophila has been sequenced (Adams et al., 2000), and EST cDNAs are available from multiple libraries representing different stages of development (BDGP, http www.fruitfly.org ). The availability of both genomic sequence and cDNA clones has increased the efficiency of forward and reverse genetic approaches (for review, see Adams and Sekelsky, 2002). Mutant screens for novel genes remain a primary tool of Drosophila neurobiologists (for examples of reviews, see Broadie, 1998 Garcia-Alonso, 1999 Wager-Smith and Kay, 2000 Featherstone and Broadie, 2000 Waddell and Quin, 2000 Sokolowski, 2001 Jin, 2002 for general review about the methods and rationale of Drosophila screens, see St. Johnston, 2002). Screens involve mutagenizing the genome with transpos-able elements (e.g., P-element), chemical mutagens or ionizing radiation, and screening for desired phenotypes. A new method of screening is through the use of a double element consisting of a transposable element...

Overview Of Spri Methodology

Surface plasmon resonance (SPR) is a surface-sensitive optical technique that can be applied to the real-time monitoring of biomolecular adsorption and or desorption events at biopolymer layers formed on a thin gold film or other noble metal surfaces. Surface plasmons are electromagnetic waves that propagate along a metal dielectric interface. The optical field intensity of the surface plasmon waves decays exponentially from the surface of the metal into the dielectric layer. For a gold film, this decay length is about 200 nm, thus defining a region where the SPR response is sensitive to localized changes in refractive index due to

Radiation Effects and Safety

The International Commission on Radiological Protection (ICRP) declares that the primary aim of radiological protection is to provide an appropriate standard of protection for man without unduly limiting the beneficial practices giving rise to radiation exposure. Nuclear medicine professionals have a duty to fellow healthcare workers, patients and their families, research volunteers, the general public and the environment to ensure the safe and responsible handling of radioactive materials used diagnostically, therapeutically and in research. Radiation protection, the observance of these safe practices, is the responsibility of every nuclear medicine professional in conjunction with the local Radiation Safety Officer (RSO), Radiation Safety Committee, government regulatory agencies and scientific advisory groups (Table 1). Energy emitted during the radioactive decay process interacts with the matter it encounters and is the basis for its detection, therapeutic effect and any...

Myths and Truths in Ocular Traumatology

By tradition, decisions in such challenging cases were always made by the department chairman. He determined that in this case the IOFB required so urgent a removal that surgery could not be delayed for general anesthesia to become available. All ophthalmologists at the department were present in the OR, and collectively held their breath, as the chairman manipulated the EEM giant head - a sphere larger than the patient's head (Fig. 1.6.1). Its conical tip was moved closer to the eye until contact, then the chairman stepped on the pedal, activating the electromagnetic field. When the IOFB presented at the wound a few seconds later, ophthalmologists in the OR sighed with relief - it was only the patient who screamed I lost my vision .

Dose For Toxic Nodular Goiter

Radiation exposure to normal thyroid tissue in the setting of solitary toxic nodules has never been shown to increase the incidence of thyroid cancer. This is likely because uptake in the normal thyroid tissue is suppressed. Nevertheless, For toxic multinodular goiters, doses of 150 Gy may be adequate to resolve hyperthyroidism. Administered activities between 3.7 and 7.4 MBq (100-200 mCi) per gram have been shown to be effective (18). Fixed administered activities (e.g., 1110 MBq) have also been used. Not uncommonly, patients with toxic multinodular goiters may have large glands and 24-hour RAI uptake measurements that are not significantly elevated. This may necessitate the administration of relatively large amounts of radioactivity. In the United States, higher administered activities may be used for nonhospitalized patients, if it can be documented that radiation exposure to the public is not likely to exceed 5 mSv (0.5 rem) (23).

Small Cell Lung Carcinoma

SCLC is a highly aggressive type of lung cancer that expresses neuroendocrine markers such as 5-hytroxytryptamine (5-HT, serotonin), mammalian bombesin (MB), calcitonin, neuron specific enolase, and others. SCLC does not harbor activating point mutations in K-ras, but frequently demonstrates amplification of c-myc and mutations in the retinoblastoma and p53 genes 51 . The majority of SCLCs are though to have derived from the epithelial lining cells of large airways while a small population of SCLCs may derive from small airway epithelial cells. SCLC initially responds well to conventional cancer therapy but relapses frequently and progresses rapidly with extensive metastasis to extrapulmonary organs. Of all histological lung cancer types, SCLC shows the closest association with smoking, and a diagnosis of SCLC is very rare in non-smokers 52, 53 . Ionizing radiation and exposure to chloromethyl ethers are additional risk factors 53 .

Radiation Safety Officer

It is the responsibility of a radiation safety officer (RSO) to ensure that the daily operation of a nuclear cardiology imaging facility is in compliance with radiation safety regulations. A RSO should help in developing policies and procedure protocols for radiation safety. The RSO should provide input with the set-up of the hot lab area and should ensure that all necessary areas are adequately lead-shielded. Furthermore, the RSO will make sure that all necessary equipment for handling and monitoring of radioactive materials is available. The RSO will also help in monitoring the radiation exposure of patients, staff, and environment such that exposure levels are as low as reasonably achievable (ALARA). The RSO also may help in setting up guidelines for patient dosing. Written protocols and policies should be in place to ensure compliance with regulations. Responsibilities of a RSO are listed in Table 3-1. Instruction and training of personnel in radiation safety Monitoring personnel...

Patient Instructions Precautions And Followup

Following the administration of therapeutic doses of RAI, contamination from excretion of RAI in urine, perspiration, breastmilk, and saliva, can be associated with internal accumulation of RAI by others who come in contact with the patient. Potential avenues of radiation exposure to others include ingestion of iodine-131 excreted by the patient, and from emitted gamma rays from iodine-131 (Table 3). Although there is little evidence to suggest that small amounts of radiation from iodine-131 treated patients can cause significant problems to others, guidelines have provided simple recommendations to reduce unnecessary radiation exposure, especially to pregnant women, infants, and children. It is a requirement of the United States Nuclear Regulatory Commission to give patients verbal and written instructions prior to treatment with RAI.

Contraindications To Radioactive Iodine Therapy

A patient who is pregnant should not be treated with RAI (7). RAI crosses freely into the placenta, and the fetal thyroid tissue is capable of accumulating iodine after the 12th week of gestation. Administration of RAI during this period may result in severe neonatal hypothyroidism. Fetal and neonatal thyroid irradiation may also increase the risk of developing thyroid cancer later. Retained activity in the maternal bladder may also increase the risk of malignancy by direct radiation exposure to the fetus. Women who are actively lactating or nursing also should not receive RAI. Iodine is excreted in breast milk. NIS protein expression is also increased significantly in mammary tissue during lactation, thus increasing the radiation exposure to the breast. Nursing should not be resumed until the birth of the next child.

Radiation Ogg1 And 8hydroxyguanine

OGG1 activity was found to be enhanced by oxygen tension and redox-cycling compounds, for example, in rat kidneys treated with potassium bromate (KBrO3) (26) or ferric nitrilo-triacetate (27), in the ischemic-perfused rat heart (28), in mouse brain (29), and in cells exposed to ionizing radiation (30). This adaptive response of oh8Gua repair enzyme to oxidative stimuli in mammals indicates its importance in the maintenance of genetic integrity, which is constantly threatened in the aerobic environment. Alternatively and positively, the importance of oh8Gua repair enzyme in cell survival under conditions of oxidative stress can be assessed by comparing the effects of such stress in cells or in animals deficient in this enzyme with that observed in wild type organisms. OGG1 was found to play an important role in protection against radiation induced cytotoxi-cities, during examinations of the functions of KG-1, a leukemia cell line without OGG1 activity. This conclusion was supported by...

Targeting DNA Repair for Tumor Radiosensitization

Another potential area for targeted radiosensitization involves the use of inhibitory drugs or proteins directed at double-strand break repair. As stated earlier, RAD51 is over-expressed in several clinically radioresistant tumors such as pancreas cancer. Additionally, ionizing radiation treatment can induce expression of RAD51 RNA and RAD51 proteinmediated homologous recombination of double-strand breaks in both normal and human tumor cells. At present, imatnib mesylate (Gleevac Novartis) is a potential candidate for clinical testing of inhibiting RAD51 at its tyrosine 315 phos-phorylating site.84

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