EXPERIMENTAL INVESTIGATION ON THE RELATIONSHIP BETWEEN LEAD EXPOSURE AND THYROIDS IN DIABETES

Lead exposure can cause multiple systemic toxicities, particularly affecting the hematopoietic, nervous and renal systems. However, its effects on the thyroid functions are not well elucidated and the published studies are controversial. In addition, although there are several experimental thyroid models, each one of them has its own limitations. Accordingly, in this dissertation, we investigated the possible relationship between lead exposure, thyroid functions and short-term systemic toxicity in two animal models, namely normal (non-diabetic) and diabetic animals. We also investigated the possibility of developing a hormonal thyroid model. In the non-diabetic model, Wistar rats were divided into five groups and treated for five days. The four treatment groups received 1, 25, 50, or 100 mg/ kg of lead acetate trihydrate intraperitoneally (i.p.), respectively. The control group received i.p. injections of distilled water. In the diabetic model, diabetes was induced with an i.p. injection of 60 mg/ kg streptozocin (STZ). Six weeks later, lead exposure experiments started. Here, four groups were studied: a control; and 25, 50 and 100 mg/ kg lead acetate groups. In each model, the measured blood lead levels correlated very well with the administered doses of lead acetate. Treatment of the animals with lead acetate resulted in significant weight loss in both models. Lead exposure caused a dose-related increase in thyroid stimulating hormone (TSH) in non-diabetic and diabetic animals. Although, thyroxine (T4) and triiodothyronine (T3) levels remained within normal range in non-diabetic animals, their levels were reduced in diabetic animals. The highest dose of lead (100 mg/ kg) significantly increased white blood cell counts and caused a significant decrease in the number of platelets in non-diabetic animals. In addition, C-reactive protein levels increased significantly in response to lead exposure in this model. Moreover, there was a significant increase in lactate dehydrogenase (LDH), aspartate aminotransferase, total bilirubin, and urea levels; following lead exposure in non-diabetic animals. In comparison, lead exposure in diabetic animals increased urea levels and caused a significant decrease in creatinine levels in plasma. While the concentrations of malondialdehyde were not affected, glutathione stores were depleted in response to lead exposure in the diabetic animals. In the last stage, we tried to develop a new experimental thyroid model, based on the use of hormones. In this experiment, animals were treated for five days with either thyrotropin-releasing hormone (TRH) or octreotide (OCT) to induce hyperthyroidism or hypothyroidism, respectively. Although there were no effects on T4 and T3 levels, TRH was effective in causing an increase in TSH levels. However, TRH also elevated LDH levels. The use of TRH did not cause any other side effects on the tested parameters, which included weight change, oxidative stress markers and renal and hepatic functions. In comparison, OCT failed to affect TSH, T4 and T3 levels, at the dose and treatment duration that we used. In conclusion, short-term lead exposure in healthy and diabetic animal models affected the functions of the anterior pituitary and thyroid glands, caused oxidative stress, liver and kidneys toxicity and induced systemic inflammation. In addition, we found that TRH has a potential to induce hyperthyroidism in experimental animals

Aerospace medicine and biology: A continuing bibliography with indexes, supplement 183

This bibliography lists 273 reports, articles, and other documents introduced into the NASA scientific and technical information system in July 1978

Protein stability in a proteomic perspective

Dissertation presented to obtain the Ph.D degree in BiochemistryThis work involved the identification and analysis of the properties of the most stable proteins present within proteomes, aiming at obtaining a general perspective of the factors that determine protein stability. As models we have focused on ensembles of proteins with high intrinsic stability, and for this purpose we have studied proteomes from the hyperthermophilic archaeon Sulfolobus solfataricus and Sulfurisphaera sp., whose properties were compared to those of the mesophilic bacterium Escherichia coli.(...

USSR Space Life Sciences Digest, Issue 18

This is the 18th issue of NASA's USSR Life Sciences Digest. It contains abstracts of 50 papers published in Russian language periodicals or presented at conferences and of 8 new Soviet monographs. Selected abstracts are illustrated with figures and tables from the original. A review of a recent Aviation Medicine Handbook is also included. The abstracts in this issue have been identified as relevant to 37 areas of space biology and medicine. These areas are: adaptation, aviation medicine, biological rhythms, biospherics, body fluids, cardiovascular and respiratory systems, cytology, developmental biology, endocrinology, enzymology, equipment and instrumentation, exobiology, gastrointestinal system, genetics, gravitational biology, group dynamics, habitability and environmental effects, hematology, human performance, immunology, life support systems, man-machine systems, mathematical modeling, metabolism, microbiology, musculoskeletal system, neurophysiology, nutrition, operational medicine, perception, personnel selection, psychology, radiobiology, reproductive biology, space biology and medicine, and space industrialization

Pesticides in the Modern World

The introduction of the synthetic organochlorine, organophosphate, carbamate and pyrethroid pesticides by 1950's marked the beginning of the modern pesticides era and a new stage in the agriculture development. Evolved from the chemicals designed originally as warfare agents, the synthetic pesticides demonstrated a high effectiveness in preventing, destroying or controlling any pest. Therefore, their application in the agriculture practices made it possible enhancing crops and livestock's yields and obtaining higher-quality products, to satisfy the food demand of the continuously rising world's population. Nevertheless, the increase of the pesticide use estimated to 2.5 million tons annually worldwide since 1950., created a number of public and environment concerns. This book, organized in two sections, addresses the various aspects of the pesticides exposure and the related health effects. It offers a large amount of practical information to the professionals interested in pesticides issues

Hazardous Waste Management

This book presents a comprehensive overview of hazardous waste and hazardous waste management. It describes the various types and constituents of hazardous waste, discusses hazardous waste management techniques and technologies, and highlights techno-economic considerations and key issues in remediation. It is a useful resource for waste management and treatment professionals, chemical engineers, technicians, medical professionals, and environmental regulators as well as students studying hazardous waste management, environmental engineering, and environmental science

Apoplastic proteins, enzymes and radicals

The soluble and readily extractable part of the plant extracellular matrix has been termed, the apoplast and contains a wide range of components such as, complex carbohydrates, structural proteins, enzymes and radicals that are known to be responsive to stress and developmental pressures. This thesis describes the development of a technique for the selective enrichment of apoplastic components for a range of subsequent analyses. Using this technique a number of apoplastic proteins were N-terminally sequenced and revealed 2 cell wall related enzymes, an antifungal protein and 3 auxin-binding/germin-like proteins. This technique also provided a novel approach to the further study of auxin-binding proteins via the use of affinity chromatography at their putative site of action, the apoplast. Three potential auxin-binding protiens were identified. Many attempts were made to subject the material extracted from the apoplast to the highly resolving technique of 2-dimensional electrophoresis, and during the process two unusual 2D systems were developed. These systems could be run in a small format that permitted very rapid analysis and/or using an in-gel loading strategy to subject up to 500µg of protein to 2D separation therefore permitting N-terminal sequencing from single 2D gels. Unfortunately 2D separation of apoplastic proteins was never fully achieved within the time frame of this study due to the vast degree of heterogenity present in the sample material. It did however demonstrate the very complex nature of apoplastic components. A series of experiments revealed that the tobacco leaf apoplast contained compartment specific antioxidant enzymes, some of which share physical characteristics with similar enzymes from other species. The activity of these enzymes altered in response to stress and according to the developmental age of the tissue. The reduced activity of these enzymes directly correlated to the degree of oxidative modification of apoplastic proteins illustrating that these enzymes are important in the detoxification of apoplastic radicals. Follow on experiments following the apoplastic generation of the superoxide anion and nitric oxide from impact stressed potato tuber tissue showed that radicals play important roles in the responses of plant tissue to stress, and show the first involvement of nitric oxide in plants in response to abiotic stress

Toxicological profile for copper : draft for public comment

Date DescriptionApril 2022 Draft for public comment releasedSeptember 2004 Final toxicological profile releasedOctober 1990 Final toxicological profile released20221169