Effect of nickel chloride on body temperature and behavioral thermoregulation in the rat

This study was designed to assess the effects of acute nickel chloride administration on behavioral and autonomic thermoregulation in the rat. In one experiment, male rats of the Fischer 344 strain were injected with nickel chloride (IP) at dosages of 0 to 24.0 mg/kg and placed in an environmental chamber maintained at an ambient temperature (Ta) of 10 or 20 degrees C. Colonic temperature was measured 60 min postinjection. Nickel chloride caused a dose-related decrease in colonic temperature, and the hypothermia was accentuated at the cooler Ta. In a second study, rats injected with 0, 6.0, 12.0, or 24.0 mg/kg nickel chloride were placed in a temperature gradient which allowed the rats to select their preferred thermal environment. Nickel chloride at dosages of 12.0 and 24.0 mg/kg caused a significant reduction in the selected Ta. At these dosages the rats were also significantly hypothermic at 60 min postinjection. In a third experiment, whole-body oxygen consumption (i.e., metabolic rate) was measured at Ta's of 10, 20, and 30 degrees C following a 12.0 mg/kg injection of nickel chloride. Nickel chloride caused an initial depression in metabolic rate and hypothermia at Ta's of 10 and 20 degrees C but not at 30 degrees C. In conclusion, (a) nickel chloride affects both behavioral and autonomic control of thermoregulation in the rat and appears to induce a regulated decrease in body temperature and (b) the behavioral thermoregulatory response of the rat is less sensitive to nickel chloride when compared to the mouse.     

Design and conduct of occupational epidemiology studies: III. Design aspects of case-control studies

Currently available approaches for the design of occupational case-control studies are reviewed. An accompanying paper reviews methods of analysis. We commence by drawing a distinction between cohort-based and registry-based studies. Methods for selecting cases and controls are then reviewed, including cumulative incidence and incidence density sampling, matching, sources of controls, and issues in control selection. Finally, the advantages and disadvantages of the case-control approach are summarized.     

Correspondence analysis as a screening method for indicants for clinical diagnosis

In clinical diagnosis, a patient's symptoms are observed and the probabilities of various diseases are assessed. A widely used method of formalizing this approach is independent Bayes in which symptoms are assumed to be independent conditional on the disease category. Correspondence analysis provides a method for examining the dependence between symptoms and assists in the selection of a reduced set of symptoms for the application of the independent Bayes method. This approach is illustrated on two data sets concerned with patients attending Accident and Emergency departments with chest pain and acute abdominal pain, respectively.     

The effect of tartrate on bone cell acid phosphatase activity: a quantitative cytochemical study

Tartrate-resistant acid phosphatase activity (TRAPase) is widely used as a cytochemical marker to distinguish osteoclasts from macrophages and other related cell types. The degree of tartrate resistance, however, may depend on which reaction methods, tissues, or species are used. To investigate this further, we have measured the amount of cytochemical reaction product by microdensitometry. We compared osteoclast acid phosphatase (APase) activity in fresh frozen sections of neonatal rat calvaria using two different reaction methods; one is commonly employed for qualitative histochemistry and includes alpha naphthyl phosphate as substrate, simultaneous coupling to the chromagen Fast Garnet, and a 30-minute reaction time (method A). The other may be used to measure enzyme reaction rates in cells in situ and employs conditions suitable for initial velocity kinetics, namely naphthol-ASBI phosphate as substrate, post coupling to Fast Garnet, and a 2-minute reaction time. Although enzyme reaction rates differed greatly between the two methods, significant inhibition of APase activity by tartrate was observed in calvarial osteoclasts (69% and 59% with methods A and B, respectively), osteoblasts, and spleen macrophages. Using method B, mouse calvarial osteoclasts had similar APase activity to that seen in the rat. Tartrate produced little inhibition in these mouse cells, in contrast to the observations made with rat tissue, but murine spleen macrophages were significantly tartrate sensitive (40% inhibition with tartrate). On this basis, conclusions regarding the cell specificity of TRAPase should be treated cautiously.     

Assessment of echographic regression criteria in ruthenium-irradiated melanoma

Steady flattening of the tumor, increasing reflectivity and decreasing vascularity are echographic signs of successful irradiation treatment. The specific example of an irradiated choroidal melanoma shows that the absence of echographic changes by no means excludes tumor destruction. Because of a dense vitreous body hemorrhage, the melanoma could only be evaluated echographically. Since the echogram lacked evidence of regression, the tumor was locally resected 5 months later. Histology, however, revealed an amorphous mass of dead tissue pervaded by intact vessels. Apparently a successfully irradiated melanoma may generate an echo typical of vital melanoma tissue. The authors therefore draw the conclusion that only a steady tumor growth, as substantiated by an echogram, may be considered an unambiguous sign of tumor vitality.     

Uveal melanoma radiation. 125I brachytherapy versus helium ion irradiation

The optimum radiation therapy for uveal melanoma is uncertain. Both helium ion irradiation and 125I brachytherapy have been used to treat this neoplasm. This investigation analyzed the control and complication rates of uveal melanomas treated with helium ions of 125I plaques. In both a retrospective and a prospective dynamically balanced study, the control rates appeared to be similar. There were more posterior segment complications after 125I plaques and more anterior segment complications, including neovascular glaucoma, after helium ion irradiation. The follow-up period is too short to draw definitive conclusions on the radiation complications. Overall, approximately 89% of eyes were retained and less than 4% of treated eyes were removed because of failure to control the tumor.     

Apparent inactivation of alpha 1-antiproteinase by sulphur-containing radicals derived from penicillamine

alpha 1-Antiproteinase is the major inhibitor of proteolytic enzymes, such as elastase, in human plasma. Its elastase-inhibitory capacity can be inactivated by exposure to hydroxyl radicals (.OH) generated either by pulse radiolysis or by an Fe3+-EDTA/H2O2/ascorbic acid system. Inactivation of alpha 1-antiproteinase by radiolytically-generated .OH under anoxic conditions was decreased by adding a range of anti-inflammatory drugs to the reaction mixtures, including the thiol compound penicillamine. However, under conditions favouring formation of oxysulphur radicals, protection by thiols such as penicillamine was much decreased. It is proposed that sulphur-containing radicals resulting from attack of biologically-produced oxidants upon penicillamine in the presence of O2 can themselves inactivate alpha 1-antiproteinase, and that such radicals might contribute to the side-effects produced by penicillamine or gold thiol therapy in rheumatoid arthritis.