Microstructural Changes In The Thyroid Gland Of The Preweaning And Weaning Rats After Heterotypic Stress

Chronic stress modulates the activity of various neuroendocrine axes; while activation pattern of the hypothalamo-hypophyseo-adrenal axis (HHAA) is studied in details, the response of the hypothalamo-hypophyseo-thyroid axis (HHTA) is less understood, especially in terms of its response to different types of stressors by the follicular and parafollicular compartments of the thyroid gland. Recent papers presented data on the inhibitory effect of chronic stress on the HHTA, while exercise and low temperature were shown to be able to activate its function. Most studies were done on the adult experimental animals using genetic studies without consideration of the structural changes in the peripheral link of the HHTA in the growing body. Reports on the effect of the chronic variable stressors on the thyroid gland in early life are scarce, though during this period neuroendocrine axes are extremely sensitive to different adverse factors, such as stress, infection, inflammation and environmental changes. The objective of this research is to assess the microscopic changes in the thyroid gland of the preweaning and weaning rats exposed to chronic heterotypic stress compared to the homotypic one. Homo- or heterotypic stressors were chronically applied to the preweaning and weaning rat pups. After the end of the last stress session the animals were euthanized, thyroid gland was sampled, embedded in paraffin, sectioned and stained for thyroglobulin, calcitonin, proliferative cells nuclear antigen (PCNA) and caspase 3. The mucosa of the alimentary tract of the experimental animals was examined and the thymus and the adrenal glands were sampled and weighed to evaluate the depth of stress-induced changes in the body. Immunologically stained slides of the thyroid gland were assessed using Image Pro+ software. Our study showed that chronic stress resulted in the structural and immunohistochemical changes of the thyroid gland in the preweaning and weaning experimental animals which indicate an inhibition of its function in the type of stress-related pattern. Both homo- and heterotypic stressors caused microscopic alterations in the thyroid gland, the extent of which depended both on the initial age of the experimental animal and the type of the stressor applied. The number and the size of the thyroglobulin-positive cells significantly decreased, and the volume density of the apoptotic cells significantly increased in the heterotypically stressed rat pups of both age subgroups with higher level of significance in the preweaning age subgroup. The number of calcitoninocytes was significantly increased in the weaning rat pups exposed to the heterotypic stress. The number of PCNA-positive cells significantly decreased only in the heterotypic stress group of both ages with higher level of significance in the preweaning age subgroup. A positive correlation was found between the volume density of the thyroglobulin-positive cells and the severity of the accidental thymic involution. Thus, our research demonstrated that weaning period is very sensitive to chronic stress for the thyroid gland of the experimental animals which by this age becomes mature enough to differentially respond to the various types of stress (homotypic versus heterotypic) both by the thyroid follicular and parafollicular compartments, and that thymus plays an important role in the functional capacity of the thyroid gland during stress in early life

Features of the Restoration of Arterial Circulation in Liver Transplantation

Objectives. Violations of tissue blood supply remain one of the most serious complications after liver transplantation. Design. To improve the surgical technique of performing reconstructive interventions on the arteries of the donor and the recipient in order to reduce the frequency of its thrombosis after liver transplantation. We studied 25 donors, 20 men and 5 women, the mean age was 56± 4 years, eighteen of them had left aberrant supplementary artery, which in fifteen departed from the left gastric artery and in three from the aorta above the ventricular stem. Seventeen had the right aberrant artery moving away from the upper mesenteric artery. Twenty recipients with liver cirrhosis (eleven with primary biliary cirrhosis, five with primary sclerosing cholangitis, five with viral etiology C cirrhosis, and three of the lower cirrhosis-cirrhosis disseminated within the Milan criteria. All recipients had standard anatomical branching of the arteries of the liver. The average age was 50±6. All recipients had standard anatomical branching of the liver arteries. Patients underwent liver transplantation with new methods of reconstructive interventions on the donor and recipient arteries. The developed technique provides the shortest pathway of the recipient's arterial blood to the liver transplant, through the superior mesenteric artery provides an alternative source of arterial blood supply from the aorta in which this transplant additionally needs. Presented method of blood circulation restoration at liver transplantation at abnormal structure of arterial channel of the liver transplant is performed inside the recipient's abdominal cavity. At first, blood flow is restored along the reconstructed common hepatic artery, after the right or left aberrant arteries liver transplant. Such technique provides the shortest route of the recipient's arterial blood to the liver transplant, through the upper mesenteric artery provides an alternative source of arterial blood supply from the aorta for which the transplant is additionally needed. This new method of blood circulation restoration provides an opportunity to avoid the formation of "kinking" syndrome, in the occurrence of which the blood vessels are lengthened, the angulation and location of the blood vessel in relation to the grafts and other abdominal organs. This reduces the risk of thrombosis of the arteries of the transplanted liver

Is it time for transition from the subject-based to the integrated preclinical medical curriculum?

In the 60s of the last century, a number of new universities in the world began to apply an integrated program of medical education, the cornerstone of which was problem-oriented education. Thus, the Flexner model of higher education adopted by that time in most countries of the world, with its characteristic segregation of teaching of the theoretical and clinical disciplines, which had ceased to satisfy the needs of modern healthcare, was gradually replaced by a new system that put the student in the center of the educational process and opened the way to active methods of teaching being focused on the end result – training of graduates whose qualifications most fully satisfy the needs of society. Over the half-century history of its existence, this system has been adopted by most medical universities in different countries of the world, in many of which it has undergone significant modifications in accordance with the needs of national educational standards. Many medical universities in Russia and other countries of the former Soviet Union showed interest in this system, some of the medical faculties of our country accepted certain elements of it. However, up to date no integrated preclinical medical education program has been applied in any of the Russian universities. Hereby we are undertaking an attempt to analyze the reasons and assess the possible perspectives for the transition of medical universities in Russia to teaching of fundamental and biomedical disciplines using the integrated curriculum