[Nephron epithelial changes of the obstructive kidney in unilateral ureteral obstruction (experimental study)]

INTRODUCTION

The high prevalence of kidney diseases caused by urinary tract obstruction has led to the need for experimental studies of the dynamics of pathological processes in their lesions. Despite the fact that the general patterns of development of obstructive uropathy are known, the features of renal tissue damage, in particular structural and molecular biological changes in this pathology, remain insufficiently studied.

OBJECTIVE

to study the dynamics of changes in the phenotype of epithelial cells of the nephron of an obstructive kidney with unilateral ureteral obstruction using an experimental model.

MATERIALS AND METHODS

The experimental study was carried out on the basis of the Rostov State Medical University. The model of unilateral ureteral obstruction was reproduced in adult rabbits. The studies were carried out on the 7th, 14th and 21st days of complete obstruction of the left ureter. Immunophenotyping of obstructive kidney tissue samples was performed for markers of epithelial phenotype (cytokeratin 7, E-cadherin) and mesenchymal phenotype (vimentin, - smooth muscle actin).

RESULTS

The sequence of changes in the phenotype of nephron epithelial cells during ureteral obstruction has been established. The first signs of an epithelial-mesenchymal transition (EMT) appear by day 7 in the form of a decrease in visualization of markers of the epithelial phenotype. On the 14th day, the expression of both epithelial and mesenchymal markers is noted. Significant changes in the phenotype of nephron epithelial cells: loss of epithelial markers (cytokeratin 7, E-cadherin) and the acquisition of mesenchymal markers (vimentin, - smooth muscle actin), are noted by the 21st day of the experiment.

CONCLUSION

An experimental model of unilateral ureteral obstruction revealed the transformation of the nephron tubule cell phenotype from epithelial to mesenchymal.

Development Features of the Endogenous Intoxication During Experimental Obstruction of the Urinary Tracts

The purpose of the study: is to establish the characteristics of the development of endogenous intoxication during experimental obstruction of the urinary tract. Materials and methods: to achieve this goal, one control and three experimental groups of animals were formed, in which blood was taken from the marginal ear vein on the 3rd, 7th, 14th and 21st day of the experiment. The following parameters were determined in blood serum: urea, creatinine, total protein and albumin. The level of endogenous intoxication was assessed by the indicators of medium-mass molecules, circulating immune complexes and malon dialdehyde. Results: statistical analysis of blood biochemical parameters and endogenous intoxication markers confirm the link between modern biomarkers of renal injury and morphological changes in the tissues of obstructive and compensatory organs. Conclusion: our findings point to the overstress adaptation mechanisms, the development of oxidative stress and exhibit a high level of endogenous intoxication, resulting in structural and metabolic changes in the affected and in the contralateral kidney.

[The influence of corticosteroids on the frequency of vestibular crises]

The objective of the present study was to elucidate the dynamics of the hormonal status of the adrenal glands in the patients suffering from Menière's disease in its different clinical forms. We examined a total of 26 patients at the age from 29 to 47 years presenting with this condition. All the patients were divided into two groups depending on the character of the disease. Group 1 was comprised of 20 patients experiencing the crises from 2 to 6 times during a year. Group 2 was composed of six patients in whom the crises occurred with a frequency of 2-4 times per week within at least two weeks. The serum levels of cortisol and aldosterone were measured both during the crises and between them with the use of the proper immunoenzyme assays. The control group was formed of 20 practically healthy volunteers. It was shown that the blood cortisol level during a fit of dizziness in the patients of group 1 increased in comparison with that in the control subjects (798.7±71.2 nmol/l and 453.68±49.39 nmol/l respectively; p<0.05). The patients having recurrent crises (group 2) experienced a significant decrease in the blood cortisol levels down to 293.5±38.1 nmol/l during a crisis in comparison with the control subjects (453.68±49.39 nmol/l; p<0.05). During the inter-crisis periods , the blood cortisol level in the patients of the first group remained within normal bounds whereas in the patients of the second group its mean value was 18.7% lower (p>0.05). The serum aldosterone level in the patients of the first group was not significantly different from that in the second group both during crises and in the periods of remission. It is concluded that the results of the study provide the data for the pathogenetic substantiation of the possibility for the use of corticosteroids in the treatment of the patients suffering from frequent crisis of Menière's disease.

[Biochemical characteristics of compensation of posthemorrhagic anemia in patients presenting with nasal bleeding]

This work was designed to study the development of compensatory processes during posthemorrhagic anemia in 82 patients presenting with nasal bleeding (NB). The patients were allocated to three groups. Group 1 included patients with isolated episodes of NB, group 2 was comprised of patients in a moderately severe condition with recurring NB, group 3 was composed of patients in a severe condition with recurring NB. The general medical examination was supplemented by the evaluation of factors maintaining the oxygen-transporting function of the blood (hemoglobin affinity for oxygen, erythrocyte content of 2.3-diphosphoglyceric (2.3-DPG) acid as the principal modulator of hemoglobin affinity for oxygen) and indicators of energy (carbohydrate) metabolism in plasma and erythrocytes (glucose-6-phosphate dehydrogenase (G-6-PDH) activity, pyruvic acid (PA), lactate and lactate dehydrogenase (LDH) levels). Changes of biochemical parameters in patients presenting with incidental episodes of NB (group 1) suggested a compensatory increase in functional potential of the blood oxygen-transporting system. Patients of group 2 showed evidence of development of the modulation-type adaptive and compensatory mechanisms. Those of group 3 experienced a decrease of the 2.3-DPH level in erythrocytes and enhancement of hemoglobin affinity for oxygen which slowed down its uptake by the tissues. Tissue hypoxia and accompanying acidosis aggravated the impairment of gas-transporting function of the blood. In is concluded that patients of group 3 are at risk of uncompensated hypoxic hypoxia associated with the unfavourable changes in the oxygen-transporting function and the impairment of the functional potential of erythrocytes. Taken together, these untoward factors may be responsible for the severe clinical conditions of these patients.

[Characteristics of prolactin secretion in response to different degrees of lesions of the vestibular analyzer]

The prolactin concentration in blood of 58 patients was measured during vestibular crisis and compensation of vestibular disorders. The results were compared with the clinical development of the disease and localization of vestibular problems. Patients with acute vestibular lesions at the central level of vestibular disorders showed a significant increase of prolactin concentrations that was higher than the concentrations in patients with the peripheral vestibular syndrome at the decompensation stage. Hyperprolactinemia during central vestibular dysfunction is viewed as a manifestation of dopamine deficiency of the tuberoinfundibular area. It is suggested that inadequacy of dopaminergic structures is one of the factors reducing adaptive and compensatory capabilities of the vestibular apparatus when its central compartments are injured.

[Changes in catecholamine metabolism in the brains of rabbits after treatment with anti-brain antibodies and lithium ions]

The authors studied the changes in the activity of tyrosine hydroxylase and dopamine-beta-hydroxylase (the principal enzymes controlling the synthesis of catecholamines) in the whole brain of rabbits on intracisternal injection of immunoglobulin G isolated from the blood of brain-sensitized dogs or from the serum of schizophrenic humans. Also the changes of the content of principal catecholamines (DOPA, noradrenaline, adrenaline) in the animals brain on intravenous injection of lithium chloride after preliminary treatment of the animals with anticerebral antibodies were studied. The changes of the activity of both enzymes in both series of the experiments appeared to be uniformly directed, the fact, that gives one grounds to regard the mechanisms underlying these disturbances as similar. A positive effect of lithium on the catecholamine metabolism in the rabbit CNS was observed. This makes is possible to recommend the model used in this study for examining the efficacy and mode of action of a number of psychotropic drugs.