Experimental rat models for Hashimoto's thyroiditis.

PURPOSE: Hashimoto's thyroiditis (HT) is an autoimmune thyroid disease characterized by T lymphocyte-mediated destruction of thyroid follicles. To study the pathogenesis of HT and the efficacy of new substances for its treatment, an easily obtained and adequate to the human disease experimental model is needed. The aim of our study was to find out whether it is possible to induce experimental autoimmune thyroiditis (EAT) similar to Hashimoto's thyroiditis by injecting with thyroglobulin (Tg) without using agents that enhance its thyroiditogenicity and without taking into account the genetic sensitivity of animals. METHODS: Wistar rats were immunized with freshly isolated rat Tg or porcine Tg. In 8 weeks, histological studies of the thyroid and parathyroid glands were performed. Thyroid function and total serum calcium level were also evaluated. RESULTS: Immunization with both rat and porcine freshly isolated Tg caused T lymphocytic infiltration of the thyroid gland, thyroid follicle atrophy and degradation in Wistar rats. EAT caused by porcine Tg was characterized by greater severity than EAT induced with rat Tg. In 55% of rats with porcine Tg-induced EAT, oxyphilic metaplasia was detected in the parathyroid glands. In addition, low total serum calcium was observed in these rats. CONCLUSION: Two rat models of autoimmune thyroiditis were obtained. EAT caused in Wistar rats by immunization with rat Tg is similar to Hashimoto's thyroiditis. EAT induced with porcine Tg was accompanied by oxyphil cell metaplasia in the parathyroids and hypocalcemia.

[Structural and functional changes of the myocardium after coronary artery bypass surgery in patients with postinfarction left ventricular remodeling]. / Osobennosti strukturno-funktsional'nykh izmenenii miokarda posle koronarnogo shuntirovaniia u bol'nykh s postinfarktnym remodelirovaniem levogo zheludochka.

In patients with left ventricular end diastolic dimensions >5--< or =5.5 cm myocardial revascularization was associated with significant decreases of diastolic and systolic left ventricular dimensions in immediate postoperative period. This adaptational phenomenon was called passive reducing left ventricular remodeling. In patients with left ventricular end diastolic dimensions <5 and >5.5 cm revascularization was associated with dilation of the left ventricle. Restoration of myocardial blood supply produced overall positive effect on left ventricular functional capacity in patients with various severity of its postinfarction remodeling. Pathways of realization of this positive effect could be different.

[Structural-geometric changes of the myocardium and the state of central hemodynamics during left ventricular remodeling after myocardial infarction]. / Strukturno-geometricheskie izmeneniia miokarda i osobennosti tsentral'noi gemodinamiki pri postinfarktnom remodelirovanii levogo zheludochka.

Intergroup analysis of parameters of central hemodynamics in the process of increase of left ventricular dimensions has shown that changes of pump function of the heart correspond to stages of left ventricular remodeling after myocardial infarction. Decreases of ejection fraction and cardiac output occur in patients with postinfarction aneurysm. At various stages of pathogenesis of remodeling multiple factors facilitate adaptation to novel conditions of functioning. They include structural reorganization of ventricular wall, hypertrophy of myocytes, and augmentation of muscular mass without wall thickening (exocentric hypertrophy). At other equal conditions characteristic for the patients studied starting point of maladaptational left ventricular remodeling and consequent development of cardiac failure can be value of left ventricular diastolic volume 182.7+/-3.28 ml. This volume according to data obtained by the authors represents a threshold over which 'rescue' for the body Staring law is not able to maintain adequate stroke volume and cardiac output.

[The method of endo-ventricular repair of the post-infarction left ventricle aneurysm]. / Sposob automiokardial'noi plastiki postinfarktnoi anevrizmy levogo zheludochka.

Functional importance of left ventricular endoventricular plastic repair in postinfarction aneurysms are discussed. It is proposed to apply vascularized muscle flap consisting of middle and internal myocardial layers as the patch. This policy permits to ensure structural-geometrical optimization of left ventricle and to increase left ventricle contractility due to involvement of automyocardial patch into active contraction.