Patient education in nuclear medicine technology practice. (1/1228)

This is the second article of a two-part series on patient education. This article builds on the first one by discussing some of the unique considerations in providing patient education in the nuclear medicine department. Concrete strategies for nuclear medicine technology practice are discussed here. After reading this article, the technologist should be able to: (a) describe the affective and technical aspects of the nuclear medicine technologist's role as a patient educator; (b) identify some strategies that nuclear medicine technologists can use to become better teachers; and (c) describe factors that affect patient learning in the nuclear medicine department and some approaches to overcome or minimize learning barriers.  (+info)

Carotenoids, sexual signals and immune function in barn swallows from Chernobyl. (2/1228)

Carotenoids have been hypothesized to facilitate immune function and act as free-radical scavengers, thereby minimizing the frequency of mutations. Populations of animals exposed to higher levels of free radicals are thus expected to demonstrate reduced sexual coloration if use of carotenoids for free-radical scavenging is traded against use for sexual signals. The intensity of carotenoid-based sexual coloration was compared among three populations of barn swallows Hirundo rustica differing in exposure to radioactive contamination. Lymphocyte and immunoglobulin concentrations were depressed, whereas the heterophil:lymphocyte ratio, an index of stress, was enhanced in Chernobyl swallows compared to controls. Spleen size was reduced in Chernobyl compared to that of two control populations. Sexual coloration varied significantly among populations, with the size of a secondary sexual character (the length of the outermost tail feathers) being positively related to coloration in the two control populations, but not in the Chernobyl population. Thus the positive covariation between coloration and sexual signalling disappeared in the population subject to intense radioactive contamination. These findings suggest that the reliable signalling function of secondary sexual characters breaks down under extreme environmental conditions, no longer providing reliable information about the health status of males.  (+info)

Bremsstrahlung radiation exposure from pure beta-ray emitters. (3/1228)

With increasing therapeutic use of radionuclides that emit relatively high-energy (>1 MeV) beta-rays and the production in vivo of bremsstrahlung sufficient for external imaging, the potential external radiation hazard warrants evaluation. METHODS: The exposure from a patient administered beta-ray-emitting radionuclides has been calculated by extending the National Council on Radiation Protection and Measurement model of a point source in air to account for biologic elimination of activity, the probability of bremsstrahlung production in vivo and its mean energy and the absorption by the patient's body of the bremsstrahlung thus produced. To facilitate such calculations, a quantity called the "specific bremsstrahlung constant" (in C/kg-cm2/MBq-h), betaBr, was devised and calculated for several radionuclides. The specific bremsstrahlung constant is the bremsstrahlung exposure rate (in C/kg/h) in air at 1 cm from a 1 MBq beta-ray emitter of a specified maximum beta-ray energy and frequency of emission in a medium of a specified effective atomic number. RESULTS: For pure beta-ray emitters, the retained activities at which patients can be released from medical confinement (i.e., below which the effective dose equivalent at 1 m will not exceed the maximum recommended value of 0.5 cSv for infrequently exposed members of the general public) are extremely large: on the order of hundreds of thousands to millions of megabecquerels. CONCLUSION: Radionuclide therapy with pure beta-ray emitters, even high-energy beta-ray emitters emitted in bone, does not require medical confinement of patients for radiation protection.  (+info)

Syndrome of recurrent increased secretion of antidiuretic hormone following multiple doses of vincristine. (4/1228)

The syndrome of inappropriate antidiuretic hormone secretion (SIADH) has been recognized to occur following treatment with vincristine. None of the reports have provided information regarding its potential for recurrence on further challenge with vincristine (VCR), an agent generally required for repeated use in patients with malignancies. Symptomatic hyponatremia and SIADH that occurred 8 days following administration of VCR in a child with acute lymphatic leukemia was documented with specific radioimmunoassay of urinary ADH levels. The further occurrence of recurrent elevations in ADH excretion 8-10 days following repeated treatment with VCR was also observed. However, SIADH was prevented by prophylactic rigorous fluid restriction. The occurrence of SIADH following VCR therefore does not preclude the further safe usage of this drug.  (+info)

Interacting populations affecting proliferation of leukemic cells in culture. (5/1228)

Peripheral blood cells from three patients with acute leukemic have been studied using a suspension culture method previously described.1 Cytogenetic studies in two of the patients permitted the identification of the proliferating cells in the cultures as being derived from a leukemic population. Cell separation studies using velocity sedimentation supported the concept that growth of the leukemic cells in culture is dependent on an interaction between two populations of leukemic cells.  (+info)

Xeroderma pigmentosum cells with normal levels of excision repair have a defect in DNA synthesis after UV-irradiation. (6/1228)

Cells cultured from most patients suffering from the sunlight-sensitive hereditary disorder xeroderma pigmentosum are defective in the ability to excise ultraviolet light (UV)-induced pyrimidine dimers from their DNA. There is, however, one class of these patients whose cells are completely normal in this excision repair process. We have found that these cells have an abnormality in the manner in which DNA is synthesized after UV-irradiation. The time taken to convert initially low-molecular-weight DNA synthesized in UV-irradiated cells into high-molecular-weight DNA similar in size to that in untreated cells is much greater in these variants than in normal cells. Furthermore, this slow conversion of low to high-molecular-weight newly synthesized DNA is drastically inhibited by caffeine, which has no effect in normal cells. Two cell lines from classes of xeroderma pigmentosum that are defective in excision-repair show intermediate effects, with regard to both the time taken to convert newly synthesized DNA to high molecular weight and the inhibition of this process by caffeine.  (+info)

Effect of ionizing radiation on transgenerational appearance of p(un) reversions in mice. (7/1228)

Multiple genetic changes are required for the development of a malignant tumor cell and many environmentally induced cancers show a delayed onset of > 20 years following exposure. In fact, the frequency of genetic changes in cancer cells is higher than can be explained by random mutation. A high level of genetic instability in a subpopulation of cells may be caused by a mutator phenotype transmitted through many cell divisions. We have determined the effects of irradiation of parental male mice on the frequency and characteristics of mitotically occurring DNA deletion events at the p(un) locus in the offspring. Reversion of the p(un) marker in mouse embryos is due to deletion of 70 kb of DNA resulting in fur spots in the offspring. We found that irradiation of male mice caused a significantly higher frequency of large spots in the offspring, indicative of the induction of DNA deletions early in embryo development. These deletion events occurred, however, many cell divisions after irradiation. The present data indicate that exposure of the germline to ionizing radiation results in induction of delayed DNA deletions in offspring mice.  (+info)

Nuclear coupling of 33S and the nature of free radicals in irradiated crystals of cysteine hydrochloride and N-acetyl methionine. (8/1228)

The 33S hyperfine structure has been observed in the electron spin resonance of irradiated crystals of cysteine-HCl-H2O and of N-acetyl DL-methionine. An analysis of the results shows that in both substances the free radicals that are stable at room temperature are disulfide radicals, RCH2SS. A possible mechanism for formation of these radicals is proposed.  (+info)