Fluorescence methods are being used increasingly in biochemical, medical, and chemical research. This is because of the inherent sensitivity of this technique. and the favorable time scale of the phenomenon of fluorescence. 8 Fluorescence emission occurs about 10- sec (10 nsec) after light absorp tion. During this period of time a wide range of molecular processes can occur, and these can effect the spectral characteristics of the fluorescent compound. This combination of sensitivity and a favorable time scale allows fluorescence methods to be generally useful for studies of proteins and membranes and their interactions with other macromolecules. This book describes the fundamental aspects of fluorescence. and the biochemical applications of this methodology. Each chapter starts with the -theoreticalbasis of each phenomenon of fluorescence, followed by examples which illustrate the use of the phenomenon in the study of biochemical problems. The book contains numerous figures. It is felt that such graphical presentations contribute to pleasurable reading and increased understand ing. Separate chapters are devoted to fluorescence polarization, lifetimes, quenching, energy transfer, solvent effects, and excited state reactions. To enhance the usefulness of this work as a textbook, problems are included which illustrate the concepts described in each chapter. Furthermore, a separate chapter is devoted to the instrumentation used in fluorescence spectroscopy. This chapter will be especially valuable for those perform ing or contemplating fluorescence measurements. Such measurements are easily compromised by failure to consider a number of simple principles."

/pdf/principles-of-fluorescence-spectroscopy-12fk61qgmp.pdf

Principles of fluorescence spectroscopy

Resistance to insulin-stimulated glucose uptake is present in the majority of patients with impaired glucose tolerance (IGT) or non-insulin-dependent diabetes mellitus (NIDDM) and in ∼25% of nonobese individuals with normal oral glucose tolerance. In these conditions, deterioration of glucose tolerance can only be prevented if the β-cell is able to increase its insulin secretory response and maintain a state of chronic hyperinsulinemia. When this goal cannot be achieved, gross decompensation of glucose homeostasis occurs. The relationship between insulin resistance, plasma insulin level, and glucose intolerance is mediated to a significant degree by changes in ambient plasma free-fatty acid (FFA) concentration. Patients with NIDDM are also resistant to insulin suppression of plasma FFA concentration, but plasma FFA concentrations can be reduced by relatively small increments in insulin concentration.Consequently, elevations of circulating plasma FFA concentration can be prevented if large amounts of insulin can be secreted. If hyperinsulinemia cannot be maintained, plasma FFA concentration will not be suppressed normally, and the resulting increase in plasma FFA concentration will lead to increased hepatic glucose production. Because these events take place in individuals who are quite resistant to insulinstimulated glucose uptake, it is apparent that even small increases in hepatic glucose production are likely to lead to significant fasting hyperglycemia under these conditions. Although hyperinsulinemia may prevent frank decompensation of glucose homeostasis in insulin-resistant individuals, this compensatory response of the endocrine pancreas is not without its price. Patients with hypertension, treated or untreated, are insulin resistant, hyperglycemic, and hyperinsulinemic. In addition, a direct relationship between plasma insulin concentration and blood pressure has been noted. Hypertension can also be produced in normal rats when they are fed a fructose-enriched diet, an intervention that also leads to the development of insulin resistance and hyperinsulinemia. The development of hypertension in normal rats by an experimental manipulation known to induce insulin resistance and hyperinsulinemia provides further support for the view that the relationship between the three variables may be a causal one. However, even if insulin resistance and hyperinsulinemia are not involved in the etiology of hypertension, it is likely that the increased risk of coronary artery disease (CAD) in patients with hypertension and the fact that this risk if not reduced with antihypertensive treatment are due to the clustering of risk factors for CAD, in addition to high blood pressure, associated with insulin resistance. These include hyperinsulinemia, IGT, increased plasma triglyceride concentration, and decreased high-density lipoprotein cholesterol concentration, all of which are associated with increased risk for CAD. It is likely that the same risk factors play a significant role in the genesis of CAD in the population as a whole. Based on these considerations the possibility is raised that resistance to insulin-stimulated glucose uptake and hyperinsulinemia are involved in the etiology and clinical course of three major related diseases— NIDDM, hypertension, and CAD.

Role of Insulin Resistance in Human Disease

A simple and rapid method is presented for the preparation of I/sup 131/- labeled human growth hormone of high specific radioactivity (240-300 mu C/ mu g). Low amounts of carrierfree I/sup 131/ iodide (2 mC) are allowed to react, without prior treatment, with small quantities of protein (5 mu g) in a highyield reaction (approx. 70% transfer of I/sup 131/ to protein). The degree of chemical substitution is minimized (0.5- 1.0 atom of iodine/molecule of protein) by the use of carrier-free I/sup 131/ iodide. The I/sup 131/-labeled hormone (up to 300 mu C/ mu g) contains no detectable degradation products and is immunologically identical with the unlabeled hormone. The loss of immunological reactivity at high specific radioactivities or at high levels of chemical substitution with STAI/sup 127/!iodine is demonstrated. (auth)

The preparation of 131i-labelled human growth hormone of high specific radioactivity

RECENT procedures for the immunological assay of protein hormones in human plasma1–3 require the routine preparation of hormones labelled with iodine-131 of high specific activity.

Preparation of Iodine-131 Labelled Human Growth Hormone of High Specific Activity

NOTE The report of the Committee without its annexes appears as Official Records of the General Assembly, Sixty-third Session, Supplement No. 46. The designations employed and the presentation of material in this publication do not imply the expression of any opinion whatsoever on the part of the Secretariat of the United Nations concerning the legal status of any country, territory, city or area, or of its authorities, or concerning the delimitation of its frontiers or boundaries. The country names used in this document are, in most cases, those that were in use at the time the data were collected or the text prepared. In other cases, however, the names have been updated, where this was possible and appropriate, to reflect political changes. Scientific Annexes Annex A. Medical radiation exposures Annex B. Exposures of the public and workers from various sources of radiation INTROdUCTION 1. In the course of the research and development for and the application of atomic energy and nuclear technologies, a number of radiation accidents have occurred. Some of these accidents have resulted in significant health effects and occasionally in fatal outcomes. The application of technologies that make use of radiation is increasingly widespread around the world. Millions of people have occupations related to the use of radiation, and hundreds of millions of individuals benefit from these uses. Facilities using intense radiation sources for energy production and for purposes such as radiotherapy, sterilization of products, preservation of foodstuffs and gamma radiography require special care in the design and operation of equipment to avoid radiation injury to workers or to the public. Experience has shown that such technology is generally used safely, but on occasion controls have been circumvented and serious radiation accidents have ensued. 2. Reviews of radiation exposures from accidents have been presented in previous UNSCEAR reports. The last report containing an exclusive chapter on exposures from accidents was the UNSCEAR 1993 Report [U6]. 3. This annex is aimed at providing a sound basis for conclusions regarding the number of significant radiation accidents that have occurred, the corresponding levels of radiation exposures and numbers of deaths and injuries, and the general trends for various practices. Its conclusions are to be seen in the context of the Committee's overall evaluations of the levels and effects of exposure to ionizing radiation. 4. The Committee's evaluations of public, occupational and medical diagnostic exposures are mostly concerned with chronic exposures of …

sources and effects of ionizing radiation

In the method presented here for the correction of sample absorption of C(14) activity, the only requirement is the availability of any C(14)-labeled compound of sufficiently high specific activity to permit addition, in negligible mass, of a number of counts equal to or greater than that in unknown samples and with solubility characteristics that exclude preferential layering during drying of samples. The principle may be applied to liquid scintillation counting. Absorption curves are dispensed with, and the weights of the assayed samples need not be determined.

Correction of Sample Absorption of Radioactivity

The role of radioimmunoassay (RIA) in the diagnosis and management of endocrine tumors, such as pituitary tumors, insulinomas, and gastrinomas, has long been well established. A variety of nonendocrine tumors are capable of elaborating one or more humoral substances that resemble immunologically well-known, well-characterized biologically active hormones or their prohormone precursors or metabolic products. The possible value of mass screening for carcinoma of the lung by the detection of precursor adrenocorticotropic hormone (ACTH) in plasma was tested. However, the usefulness was limited by the potential for false-positives, i.e., elevation of marker concentration in the plasma of heavy smokers even in the absence of invasive carcinoma. Although on occasion a dramatic decrease of plasma ACTH after surgical resection or on some chemotherapeutic schedules has been observed, this does not occur with sufficient regularity to serve definitely as an objective measure of efficacy of therapy. The limitations of nonhormonal tumor markers, such as carcinoembryonic antigen (CEA), are also considered. Cancer 53:1426-1431, 1984.

The society of Surgical Oncology Lucy Wortham James Research Award 1983. Radioimmunoassay in oncology.

https://jnm.snmjournals.org/content/jnumed/26/1/1.1.full.pdf

A Rational Policy for Biomedical Waste

Radioactivity and radiation have always existed, yet it is less than a century since we have become aware of their presence in nature and been able to exploit the knowledge of natural and man made radiation to improve our health and well being. It has been estimated that natural radiation accounts for more than 80% of the radiation exposure of the general population, with medical exposure accounting for most of the rest. There appears to be no reproducible evidence of harmful effects associated with increases in background radiation up to six times the usual levels. In the absence of smoking, the age adjusted lung cancer death rates in the USA and in the high background region of China are in the range of 2–3 per 100 000. Although many studies have shown that very high exposure of miners to the naturally radioactive gas radon and its daughter products result in a marked increase in lung cancer, there is no evidence for an increase in lung cancer among non-smokers exposed to radon related levels co...

Radiation and Society

The ready availability of inexpensive radioisotopes from the Oak Ridge reactor at the end of World War II led to the burgeoning application of these materials in biomedical investigation and the development of a new medical specialty, Nuclear Medicine. Much of this specialty is concerned with imaging, that is, administering a radioactive material to a patient and tracing its behavior in the body. Another important application is radioimmunoassay (RIA) an in vitro test that has become a major tool in thousands of laboratories around the world to measure concentrations in body fluids of hundreds, if not thousands, of substances of biologic interest. The concentmtion of an unknown substance is determined by comparing its inhibition of binding of a radioactively labeled tracer to specific antibody with the inhibitions observed with known standards. Whether these uses of radioisotopes will remain viable in the face of the pervasive fear of radiation exposure at any level is a cause for concern. The gen...

Rosalyn S. Yalow

Papers

Correction of Sample Absorption of Radioactivity

The society of Surgical Oncology Lucy Wortham James Research Award 1983. Radioimmunoassay in oncology.

A Rational Policy for Biomedical Waste

Radiation and Society

Radioactivity in the Service of Humanity