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Biomedical subjects

A V Pavlov

Publications and source records attributed to A V Pavlov.

At least 37 records · Page 2Linked to original sources
PubMed1989

[Biosynthetic activity of parathyroid cells during different function of the parathyroid glands].

By means of autoradiograph c and morphometric methods parathyroid glands of 31 rats after single injection of 3H-leucin (2,5 mc Cu/g of body mass 25 min. before killing) were investigated. Parathyroid glands were inhibited by multiple injections of calcium gluconate solution or by a diet with increased content of calcium and vitamin D2. Parathyroids were stimulated by multiple injections of Trilon B solution, by a diet with increased content of phosphates or by subtotal parathyroid resection. Straight correlation between parathyroid function, average section area of parathyrocytes and average number of silver granules per one parathyrocyte was revealed. Hence, average section area of parathyrocytes is objective morphometric criterion of parathyroid function.

Animals↗
PubMed1988

[Proliferative activity of typical thyrocytes and C cells in normal and regenerating thyroids].

By means of quantitative methods (autoradiography, estimation of the mitotic index of cells, morphometry) proliferative activity of typical (follicular) thyrocytes and C cells (calcitonicytes) has been studied in 40 rats both in control and in 1-30 days after hemithyroidectomy. For revealing C cells silver nitrate impregnation after Sevier-Munger and metachromatic reaction with toluidine blue in Sawicki's modification have been used. At repeated injections of 3H-thymidine (12 injections of 0.8 mcCi/g with the interval of 8 h) in the intact rat thyroid glands and equal amount (2-3%) of endocrine cells of the both types are labelled, in 2.5-6 days after a partial resection, amount of the labelled follicular cells increases by 10 times, while that of calcitonicyte--only by 2 times. The differences revealed can be connected with more pronounced histogenic potencies of the typical thyrocytes, realized most fully under conditions of their specific hormonal stimulation in the course of the gland restoration.

Animals↗
PubMed1988

[Participation of tissue basophils of the parathyroid glands in the regulation of the morphofunctional state of the organ].

By means of cytometry estimation of mitotic index and nucleo-cytoplasmic relation of parathyrocytes, parathyroid glands have been studied in 52 white rats and 28 white mice under conditions of intal inhibition (30 mg/kg of body mass twice a day intraperitoneally) of tissue basophils (TB) secretory activity. For stimulation of the glands, repeated injections of trilon B and hemiparathyroidectomy are used. The experiment lasts for 3.5 days. In the rat parathyroid glands, containing a considerable amount of TB, intal does not produce any important effect of quantitative parameters of the organ's structure in intact animals, nevertheless it prevents development of hypertrophy of the parathyrocytes in the stimulated glands, as well as makes weaker the proliferative response of the cells to hemiparathyroidectomy. In mice, their parathyroid glands containing single TB, under conditions of stimulation of the parathyroid function, intal does not produce any inhibitory effect to growth of middle size parathyrocytes. The results obtained demonstrate that the parathyroid TB actively participate in regulation of the organ's morphofunctional state, intensifying the stimulating effect of hypocalcaemia to the parathyroid parenchyma.

Animals↗
PubMed1988

[Restorative processes in the parathyroid glands in experimental hypothyroidism].

By means of morphological, morphometrical and autoradiographical methods restorative processes in the parathyroid glands in 41 euthyroid and in 41 hypothyroid rats have been studied during 1-24 days after mechanical trauma of the glands or after hemithyroparathyroidectomy. Seven hypothyroid and 7 euthyroid rats serve as a control. Hypothyroidism is produced with daily injection of mercazolil (6 mg/kg) 3 weeks before the operation and during the time of the experiment. In nonoperated hypothyroid rats development of hypertrophy in parathyrocytes is noted. Prolonged injection of mercazolil weakens (posttraumatic regeneration) or completely suppresses (compensatory hypertrophy) mitotic activity of the glandular cells (in comparison with the euthyroid animals). Manifestation of hypertrophy in parathyrocytes of the hypothyroid rats in comparison with the corresponding control is also less, than against the background of euthyreosis.

Animals↗
PubMed1986

[Regeneration of the parathyroid glands in experimental hyperthyroidism].

By means of morphological, morphometric and radioautographic methods, regeneration of mechanically traumatized parathyroid glands has been studied in 22 euthyroid and 22 hyperthyroid rats on the 1st-20th days after the operation. The thyroid gland is stimulated by daily injection of thyrotropin (1 ME/100 g of body mass). Twelve non-operated animals (6 hyperthyroid and 6 euthyroid rats) serve as control. In the regenerating parathyroid glands of the hyperthyroid animals in comparison with the euthyroid ones, certain increase of proliferative activity is noted in parathyrocytes and in cells of the granular tissue on the 2d-6th days, a more pronounced hypertrophy of epitheliocytes on the 2d-20th days, hyperplasia of their nucleolar apparatus on the 2d-5th days. The experimental hyperthyroidism stimulates manifestation of restorative processes in the regenerating parathyroid glands during development of active inflammatory reaction in them; however, it does not influence the parameters of the organ's structure studied in the nonoperated animals.

Animals↗
PubMed1986

[Regeneration of the parathyroid glands after partial resection].

By means of morphometrical methods, as well as by the method of volumetric reconstruction of the organs in 33 rats during 1-30 days regeneration of parathyroid glands have been studied after a simultaneous resection of the whole left and a half of the right gland. Total calcium content in blood serum in the experimental animals decreases on the 1st-2d day and normalizes by the 3d day. Regeneration of the remained part of the gland is realized at the expense of increasing mitotic activity and hypertrophy of parathyrocytes along the whole organ from the 3d up to the 13th day. There are no signs of the glandular parenchyma growth from the wound surface. On the 3d-5th day dividing parathyrocytes predominate in the half of the gland that adjoins the wound. This promotes a predominant longitudinal growth of the gland remnant and restoration of the organ's ellipsoid form on the 20th-30th day. The main pattern of the parathyroid gland restoration after its partial resection is regenerative hypertrophy.

Animals↗
PubMed1985

[Spatial organization of proliferative processes in the parathyroid glands upon acute stimulation of parathyroid function].

A quantitative analysis on homogeneity degree in distribution of proliferating parathyrocytes in the parathyroid glands under conditions of an acute stimulation of their function, produced by bilateral nephrectomy (12 rats, 50-70 h after the operation) and by hemiparathyroidectomy (12 rats, 2-3 days after the operation) have been performed. Six intact animals serve as the control. In order to reveal proliferating cells, 1 h before sacrifice 3H-thymidine (1 mc Ci/g) is injected intraperitoneally, and to some animals--colchicine (1 mg/kg) is injected 6 h before the sacrifice. By means of successive investigation of the glands serial sections along their whole area the amount of the microscope field of vision, having various content of proliferating cells are calculated; using the criterion chi 2, the correspondence of the empiric distributions obtained to the Poisson distribution are estimated. In the hyperfunctioning parathyroid glands the proliferating cells form foci of clusters and rarifaction. A similar clustering appears when a definite level of mitotic activity of the parathyrocytes is reached (1-1.2%), probably reflecting certain regional peculiarities of their functional state.

Animals↗
PubMed1985

[Cytological analysis of a population of thyroid parafollicular cells].

With the aid of Sevier-Munger silver stain, parafollicular thyrocytes (C-cells) of rat males were investigated within the period of 10 minutes to 8 hours after the intraperitoneal injection of calcium gluconate solution. In the thyroid glands of both control and experimental animals four types of C-cells at different stages of their secretory cycle were described. Relative rates of these cellular types were found to be objective quantitative criteria of the functional activity of parafollicular cell population.

Animals↗
PubMed1983

[Measurement of the diameters of nucleoli by the template method].

The method of measuring the nucleoli diameters in the light microscope is described. The nucleoli are compared to two standard templates followed by calculation of the means value and the standard deviation by means of special formulas. The scale marks of ocular micrometer or of special ocular scale can be used as the templates. The use of templates makes the measuring of nucleoli diameters 3-3.3 times as quick as the screw ocular micrometer, and with good correlation between the results obtained with both methods, too.

Animals↗
PubMed1983

[Compensatory hypertrophy of the parathyroid glands in rats].

In 40 rats 0.5-41 days after hemiparathyroidectomy the state of the contralateral organ has been studied. Thirty-eight intact animals have been used as controls. The function of the unoperated gland is considered according to the total calcium content in blood serum. The mitotic index of parathyrocytes is calculated, nucleometric and stereologic investigation of the preparations is performed. Calcium level in the test animals' blood moderately decreases on the 2d-3d days and becomes normal in 4 days. Regeneration of the remained parathyroid gland occurs at the expense of an increased mitotic activity of the main cells from the 3d up to the 11th day and by means of hyperplasia of the nucleoli and hypertrophy of cytoplasm in epitheliocytes. The weight of the hypertrophied organ is, on the 20th, day, 77, and on the 41st day--61% of the total weight of the parathyroid glands in the control rats. Analysing dynamics of 13 quantitative parameters, it is possible to reveal certain stages of the process: the latent stage (the first 24 hours), the restorative period (the 2d--the 16th day), the normalization and stabilization of the morphometrical indices (the 19th--the 41st day).

Adaptation, Physiological↗
PubMed1983

[Regeneration of the parathyroid glands following mechanical trauma].

During the interval of 3h-42 days regeneration of the parathyroid glands traumatized by means of forceps has been studied in 66 rats. The model presented reproduces the postoperative state of hypoparathyreosis occurring in the clinic. Ten intact and 30 pseudooperated animals serve as controls. The material is treated by means of histological, histochemical and morphometric methods (the stereological one including). The function of the gland is estimated according to total calcium content in blood serum. After 3-17th the parathyroid gland trauma produces some foci of parenchymal destruction. On the second day connective tissue begins developing in them. Epithelial regeneration occurs at the expense of an increased mitotic activity of the chief cells in the noninjured parts of the gland up to 0.9-1.5%, after 3-4 days hypertrophy of epitheliocytes, their nuclei and nucleoli, increasing number of nucleoli in the nucleus. After 5-10 days a limited outgrowth of the glandular parenchyma within large foci of the lesion is observed in some animals. Because of a rapid development of the connective tissue scars, however, at the place of the destroyed glandular parenchyma areas, there is no normalization of the organ's structure and function by the 42d day. A relative volume of stroma increases as much as 3-4 times as compared to the noninjured gland. The quantitative data dynamics analised demonstrate certain phasing in the regenerative processes: period of an alteration and an active macrophagal reaction (first 48 h after trauma), period of an active regeneration (the 2d - the 6th day), period of a temporary compensation (the 8th - the 13th day), period of a stable hyperfunction of the organ (the 16th - the 42d day).

Animals↗