Alteration of parafollicular (C) cells activity in the experimental model of hypothyroidism in rats.

Our previous study has shown the alteration of C cells activity in rats with experimental model of hyperthyroidism. The aim of the present study was the evaluation of parafollicular cells activity in rats with hypothyroidism evoked by propylthiouracil (PTU) given in drinking water over 21 days. Histological, ultrastructural and immunocytochemical studies using specific antibodies against calcitonin and CGRP were performed on thyroid glands taken from experimental and control groups of rats. Moreover, in all animals the calcitonin plasma levels were evaluated by radioimmunoassay. After chronic administration of PTU, thyroid image showed predominant microfollicular hyperplasia and attenuated density of parafollicular cells. The intensity of immunocytochemical reactions for CT and CGRP were weaker in the majority of C cells in comparison to the control rats, in which strong immunocytochemical reaction was observed. Examination in the electron microscope reveals the features of hypoactivity both in follicular and parafollicular cells, in which the quantity and electron density of secretory granules were smaller in comparison to the control group. These microscopic changes were accompanied by a significant decrease of calcitonin plasma concentration. Alteration of C cells activity in the experimental model of hypothyroidism, accompanied by microfollicular hypertrophy, may point to the mutual cooperation between parafollicular and follicular cells.

Is the repair of articular cartilage lesion by costal chondrocyte transplantation donor age-dependent? An experimental study in rabbits.

The repair of chondral injuries is a very important problem and a subject of many experimental and clinical studies. Different techniques to induce articular cartilage repair are under investigation. In the present study, we have investigated whether the repair of articular cartilage folowing costal chondrocyte transplantation is donor age-dependent. Transplantation of costal chondrocytes from 4- and 24-week old donors, with artificially induced femoral cartilage lesion, was performed on fourteen 20-week-old New Zealand White male rabbits. In the control group, the lesion was left without chondrocyte transplantation. The evaluation of the cartilage repair was performed after 12 weeks of transplantation. We analyzed the macroscopic and histological appearance of the newly formed tissue. Immunohistochemistry was also performed using monoclonal antibodies against rabbit collagen type II. The newly formed tissue had a hyaline-like appearance in most of the lesions after chondrocyte transplantation. Positive immunohistochemical reaction for collagen II was also observed in both groups with transplanted chondrocytes. Cartilage from adult donors required longer isolation time and induced slightly poorer repair. However, hyaline-like cartilage was observed in most specimens from this group, in contrast to the control group, where fibrous connective tissue filled the lesions. Rabbit costal chondrocytes seem to be a potentially useful material for inducing articular cartilage repair and, even more important, they can also be derived from adult, sexually mature animals.

Comparative study of changes in activity of calcitonin-producing cells in the thyroid and lungs during hypercalcemia.

The conflicting results of previous evaluations of the influence of hypercalcemia on thyroid C-cells and the absence of reports on its influence on calcitonin (CT)-producing cells of the airways prompted this study. It aims to evaluate the activity and changing dynamics in CT-producing cells in rat thyroid glands and lungs after prolonged hypercalcemia. The hypercalcemia was induced by an intraperitoneal injection of 100,000IU of vitamin D(3) (Vigantol), Merck). Control and experimental rats were examined after 1, 7 and 14 days. Calcium and CT concentrations were measured in blood plasma. Paraffin wax embedded sections of thyroid and lungs were stained with hematoxylin and eosin. CT was detected immunohistochemically in thyroid C-cells and lung endocrine cells. Results showed increased calcium and CT concentrations in rat blood after vitamin D(3) administration, a statistically significant reduction in number of CT-positive cells in the thyroid with indications of their increased activity, and a statistically non-significant reduction of the number of cells immunopositive for CT in lungs after 1 day, and an increase after 7 days, compared to the control group. Lack of an obvious correlation in lung neuroendocrine cells among the rats with hypercalcemia may indicate the presence of other, perhaps local, functions for calcitonin.

Conforming and nonconforming personality and stress coping styles in combat athletes.

The main objective of this study was to investigate whether the personality dimension of conformism/nonconformism was a predictor of stress coping styles in athletes training combat sports, and to present the characteristics of this personality dimension in the context of the competitors' adaptive/innovative sport performance. Scores of 346 males practising combat sports such as kick boxing, MMA, thai boxing, boxing and wrestling were analyzed. The participants completed the Creative Behaviour Questionnaire (KANH III) measuring the conformity/nonconformity personality dimension and the Coping Inventory for Stressful Situations (CISS) measuring stress coping styles. The comparative analyses were conducted only for the groups of conformists and nonconformists. Differences in stress coping styles between conformists and nonconformists training combat sports were found as nonconformists tended to prefer the task-oriented coping style. Conclusively, a higher rate of nonconformity was associated with increasingly frequent occurrence of task-oriented coping and decreasingly frequent emotion-oriented coping.

Immunohistochemical and electron-microscopical identification of neuroendocrine cells in the respiratory tract of rats with experimental uraemia.

The aim of the present study was to characterise immunohistochemically and ultrastructurally the neuroendocrine cells in the pulmonary systems of uraemic rats. Pieces of lung and trachea were collected 1, 2 and 4 weeks after nephrectomy. Paraffin-embedded sections were stained with H+E and by silver impregnation. For the identification of neuroendocrine cells immunohistochemical reactions were performed with the use of specific antibodies against calcitonin (CT), somatostatin (SOM), synaptophysin (SYN), neuron-specific enolase (NSE) and calcitonin gene-related peptide (CGRP). For electron microscopy, ultrathin sections were used. The analysis showed an increased number of both the solitary neuroendocrine cells and of neuroepithelial bodies in uraemic rats when compared to control animals.

The morphological and histochemical neurosecretory magnocellular system in the rat after administration of chlorpromazine.

The effect of chlorpromazine (CPZ) on the neurosecretory action of the hypothalamo- hypophyseal system was investigated in 72 male rats. The experimental animals received CPZ in a dose of 0.4 mg, 4.0 mg and 20.0 mg/kg b.w. for 30 days. The rats were sacrificed by decapitation at 24 h and 7 days after the last dose of the drug. The neurosecretory material was stained with paraldehyde fuchsin in the supraoptic nucleus, paraventricular nucleus, eminentia mediana and neurohypophysis, the tigroid was stained with toluidine blue and the acid phosphatase activity was evaluated histoenzymatically. It was found that CPZ reduced the content of the neurosecretory material after 24 h, while an increase was observed 7 days after the last drug administration.

Dactinomycin-induced veno-occlusive disease in rats. The hepatoprotective action of amifostine. Evaluation in a light and electron microscope.

The purpose of the study was to draw upan experimental model of hepatic veno-occlusive disease (VOD) induced by dactinomycin (ACT) and to investigate the possible hepatoprotective effects of Ethyol (amifostine). Pathological changes corresponding to a VOD picture of varying intensification were found in the liver samples obtained from all the rats receiving ACT. Amifostine appears to act protectively to liver changes caused by dactinomycin.

A preliminary evaluation of thyroid and respiratory tract neuroendocrine cells in the rat after experimental hypercalcaemia.

The goal of this study was to investigate the influence of experimentally induced hypercalcaemia (after 100000 UI Vigantol and CaCl2) on neuroendocrine cells (NECs) in the thyroid and airways in the rat. After 24 h, 7 days and 14 days the thyroid and lungs were collected. Paraffin sections were immunocytochemically stained with specific antibodies against CGRP, calcitonin (CT) and synaptophysin (SY) in the airway NECs and thyroid C cells. The largest hypercalcaemia were observed in experimental rats after 7 days. More significant changes in the number and size of neuroendocrine cells were observed in the thyroid gland as well as in the airways. In the airways only a slight increase in the number of neuroepithelial bodies (NEBs) was observed, some of which gave evidence of hypertrophy symptoms.

Effect of acute exposure to cadmium on the expression of calcitonin gene-related peptide (CGRP), calcitonin (CT), somatostatin (SST) and synaptophysin (SYN) in the C cells of the rat thyroid--a preliminary study.

The aim of the present study was to determine to what degree acute exposure to cadmium affects the expression of CGRP, CT, SST and SYN in the C cells of the rat thyroid. Animals from 7 experimental groups received CdCl2 iv. in doses of 3.5, 3, 2.5, 2, 1.5, 1 and 0.5 mg/kg b.w. respectively, while the control animals were given 0.9% NaCl iv. 24 hours after the iv. administration of CdCl2, a correlation was found between a single dose of cadmium and the intensity of the immunocytochemical reactions for CGRP, CT, SST and SYN in C cells of the rat thyroid when compared to the control. The weakest immunocytochemical reactions were noted in C cells of the thyroid of rats from Groups I and II, their intensity gradually increasing in Groups III, IV and V in comparison to the control. The reaction intensity in animals of Groups VI and VII resembled those of the control.

Rabbit articular cartilage defects treated with cultured costal chondrocytes (preliminary report).

An attempt to repair articular cartilage defects by costal chondrocytes transplantation was made. A full-thickness defect in the rabbit's femoral patellar groove was artificially made. Cultured costal cartilage chondrocytes were then transplanted into the defects and covered with periosteal flaps. Empty defects were used as the control group. Animals were divided into two groups (five rabbits each). They were examined after four and twelve weeks from the day of transplantation, respectively. The reparative tissue was evaluated by macroscopic and histological examinations. The reparative tissues in defects with transplanted chondrocytes had an hyaline-like cartilage appearance and were firmly attached to the surrounding normal cartilage. No trace of newly formed bone was detected. The reparative tissues found in defects that were left empty had a fibrous character. They were loosely connected to the surrounding cartilage and were more compliant than tissues from transplanted defects. Considering these initial findings, the ease of surgical procedures during the harvesting of the costal cartilage and few interventions into the joint make the costal cartilage a promising source of chondrocytes for transplantation. However, this needs to be confirmed on a larger scale over a longer period of time.

Preliminary comparative immunocytochemical study of respiratory tract endocrine cells in certain rodents.

Studies were performed on 3 species belonging to two families: Microtidae (7 common voles and 7 pine voles), and Muridae - 10 Wistar rats. In rodents the airways endocrine cells (ECs) are localised in the epithelium lining the larynx, trachea, bronchi, bronchioles and lung. CGRP-, synaptophysin (SY)-, calcitonin (CT)-, neuron-specific enolase (NSE)- and chromogranin A (CA)- immunoreactivity were nearly totally co-localised in ECs. In the region of the tracheo-larynx junction, CGRP- and NSE-positive cells were observed in the epithelium of the glands. It is surmised that some of the CGRP-positive ECs do not generate CT and CA, for the most part in ECs. In Microtidae ECs were more abundant than in the rat and were found even in the epithelium lining of the inside larynx in the transition region before the trachea.

Activity of the thyroid parafollicular (C) cells in simple and hyperactive nodular goitre treated surgically - preliminary investigations.

The aim of this study was to evaluate the significance of measuring calcitonin (CT) plasma concentrations in patients with simple and hyperthyroid goitre treated surgically. Eighty four patients who underwent operations during the years 2000-2002 were analysed. Plasma concentrations of CT were determined by commercially available radioimmunoassay on the day of hospitalisation. Elevated concentrations of CT were found in 8 patients: in 5 out of 26 (19.2%) and in 3 out of 33 (9.0%) patients with Graves' disease and with multinodular goitre, respectively. No major differences in concentrations of CT were observed in patients with simple goitre. Postoperative morphological analysis of pathologically changed hyperactive thyroids showed the presence of enlarged C cells distributed either in small groups or even singly with weakening immunohistochemical reaction for CT. These observations may point to the possibility of a relationship between the functional state of the thyroid gland and the activity of C cells.

Preliminary immunohistochemical investigations of thyroid C cells in an experimental model of hyperthyroidism.

The role of the parafollicular (C) cells, the second most important cells in the thyroid gland, has not hitherto been clarified. They are considered to be disperse neuroendocrine cells of the APUD system and synthesise and release many of the regulatory peptides. Few publications are concerned with the evaluation of the structure and function of C cells in the thyroid gland or the probable relationship between these cells and the follicular cells in physiological and pathological conditions. For this reason immunohistochemical investigations were carried out into the activity of the C cells in rats in an experimental model of hyperthyroidism caused by chronic thyroxine influence. This C-cell activity was then evaluated. Differences in the quantity, distribution and calcitonin immunoreactivity of C cells were observed in hyperthyroid rats in comparison to the control group, together with a significant diminution of plasma TSH and calcitonin levels. Our preliminary study may indicate a functional interaction between follicular and parafollicular cells in the thyroid gland.

An immunohistochemical study of the thyroid parafollicular (C) cells in rats treated with cannabinoids - preliminary investigations.

The purpose of the present study was to evaluate the effect of a single intraperitoneal injection of a stable analogue of endogenous cannabinoid anandamide - R-(+)-methanandamide (2.5 mg/kg) and CP 55,940 (0.25 mg/kg), an egzogenous CB1 receptor-agonist, on the calcitonin (CT) immunoreactivity of the thyroid parafollicular (C) cells. Four hours after injection with both cannabinoids CT immunoreactivity, evaluated with an avidin-biotin peroxidase complex method by means of rabbit antibodies against CT, was seen to be enhanced in the parafollicular cells in comparison to those of the control group. In thyroids taken from cannabinoid-treated rats the majority of follicles, particularly those located peripherally were large in size, and had low epithelium. Moreover, dilatation of the blood vessels was observed. These changes were accompanied by a significant decrease in CT plasma level, without changes in calcium concentrations. This is the first evidence that a single injection of the cannabinoids R-(+)-methanandamide and CP 55,940 significantly decreases the activity of thyroid C cells.

Physical activity levels as a quantifier in police officers and cadets.

OBJECTIVES: The aim of the present study was to determine the physical activity levels of active duty police officers and police academy cadets in different life domains and intensities. These parameters were treated as potential quantifiers that could be used when assessing individuals preparing for work as future police officers. MATERIAL AND METHODS: The study recruited 153 active police officers and 176 cadets attending a police academy and administered a diagnostic survey, the long-form version of the International Physical Activity Questionnaire, while in the statistical analysis the Student's t-test for independent groups was applied. RESULTS: It was determined that police officers present high physical activity levels within the work domain, which are developed from initial training at a police academy and then throughout their police career. CONCLUSIONS: Such data are important in the light of the role police officers play in public safety as well as the prominence of physical activity within a particular profession and how it can be targeted and tailored to their needs.

Estimation of gastric ghrelin-positive cells activity in hyperthyroid rats.

Ghrelin is a peptide of 28 amino acids that transmits appetite related signals from peripheral organs to the brain. The main source of ghrelin is stomach. The regulation of ghrelin secretion is still unknown. The finding that fasting and food intake, respectively increase and decrease the secretion of ghrelin suggests that this hormone may be a bridge connecting somatic growth with energy metabolism and appears to play an important role in the alteration of energy homeostasis and body weight in pathophisiological conditions. The purpose of this study was the evaluation of gastric ghrelin immunoreactivity and ghrelin plasma concentration in male Wistar rats with hyperthyroidism. Experimental model of hyperthyroidism was induced by intraperitoneal injection of levothyroxine at the dose of 80 microg/kg daily over 21 days. At the end of experiment the animals were anaesthetized, blood was taken from abdominal aorta to determinate plasma ghrelin concentration by RIA and then the animals underwent resection of distal part of stomach. Immunohistochemical study were performed using monoclonal specific antybodies against ghrelin. Hyperthyroidism was a reason of increase of gastric mucosal ghrelin - immunoreactivity, accompanied by a significant decreased of ghrelin plasma concentration. Those observations may indicate, that chronic administration of L-thyroxine cause the change of ghrelin plasma concentration in rats, probably via direct influence on gastric X/A-like cells, but this effect is not responsible for hyperphagia associated with hyperthyroidism.

Cannabinoids enhance gastric X/A-like cells activity.

It has been reported that cannabinoids may cause overeating in humans and in laboratory animals. Although, endogenous cannabinoids and their receptors (CB1) have been found in the hypothalamus, and recently also in gastrointestinal tract, the precise mechanism of appetite control by cannabinoids remains unknown. Recently, ghrelin--a hormone secreted mainly from the stomach X/A-like cells was proposed to be an appetite stimulating agent. The aim of this study was the evaluation of the influence of a single ip injection of a stable analogue of endogenous cannabinoid--anandamide, R-(+)-methanandamide (2.5 mg/kg) and CP 55,940 (0.25 mg/kg), an exogenous agonist of CB1 receptors, on ghrelin plasma concentration and on ghrelin immunoreactivity in the gastric mucosa of male Wistar rats. Four hours after a single injection of both cannabinoids or vehicle, the animals were anaesthetized and blood was taken from the abdominal aorta to determinate plasma ghrelin concentration by RIA. Subsequently, the animals underwent resection of distal part of stomach. Immunohistochemical study of gastric mucosa, using the EnVision method and specific monoclonal antibodies against ghrelin was performed. The intensity of ghrelin immunoreactivity in X/A-like cells was analyzed using Olympus Cell D image analysis system. The attenuation of ghrelin-immunoreactivity of gastric mucosa, after a single injection of R-(+)-methanandamide and CP 55,940 was accompanied by a significant increase of ghrelin plasma concentration. These results indicate that stimulation of appetite exerted by cannabinoids may be connected with an increase of ghrelin secretion from gastric X/A-like cells.

Interleukin-6 is not essential for bone turnover in hypothyroid mice.

Interleukin-6 (IL-6) has been shown to be involved in the pathogenesis of several bone diseases characterized by an imbalance between bone resorption and formation. The aim of the study was to estimate serum markers of bone turnover: osteoclast-derived tartrate-resistant acid phosphatase form 5a (TRACP 5b) and osteocalcin in IL-6-deficient mice to assess the role of IL-6 in bone metabolism in hypothyroidism in mice. C57BL/6J (wild-type; WT) and C57BL/6J(IL6-/-Kopf) (IL-6 knock-out; IL6KO) mice randomly divided into 4 groups with 10 in each one: 1/ WT mice in hypothyroidism (WT-ht), 2/ WT controls, 3/ IL6KO mice with hypothyroidism (IL6KO-ht) and 4/ IL6KO controls. Experimental model of hypothyroidism was induced by intraperitoneal injection of propylthiouracyl. The serum levels of TRACP 5b and osteocalcin were determined by ELISA. Serum concentrations of TRACP 5b (median and interquartile ranges) were significantly decreased in both groups of mice with hypothyroidism: WT (3.2 (2.5-4.7) U/l) and IL6KO (2.6 (1.8-3.5) U/l) as compared to the respective controls. Similarly, serum osteocalcin levels were significantly reduced in both groups of mice in experimental hypothyroidism: WT (25.8 (23.0-28.2) ng/ml) and IL6KO (21.5(19.0-24.6) ng/ml) in comparison to the respective controls. There were no significant differences in bone turnover markers between IL6KO and WT mice both in hypothyroid and control animals. The results of the present study suggest that IL-6 does not play an important role in bone turnover in both euthyroid and hypothyroid mice.

Ultrustructural and enzymatic studies of rat liver after acute cadmium exposure.

The aim of the study was to examine morphological and enzymatic changes in the rat liver following single i.v. administration of CdCl2 (5 and 10 mumol/kg b.w.). In the rats given 5 and 10 mumol CdCl2/kg b.w., a correlation was found between the dose and the intensity of changes in the liver both in pathomorphological, ultrastructural and enzymatic analyses. Pathomorphological and ultrastructural investigations showed that a single dose of 10 mumol CdCl2/kg b.w. caused vacuolar degeneration, and fatty degeneration in single hepatocytes. Structural changes were accompanied by an increase in the activity of indicatory enzymes of the liver-AST and ALT. At the same time, stimulation and activation of B-K cells were observed. However, a single 5 mumol CdCl2/kg b.w. dose induced only blurring of cell structure in single hepatocytes within the peripheral zone of the lobules, which looked as if they had been filled with pinkish "mush".