Effect of NO Synthesis Blockade on the Hydrouretic Function and Extracellular Matrix of the Kidneys in Rats with Different Blood Vasopressin Levels.

We studied the effect of NO synthesis blockade on the hydrouretic function and the state of renal interstitial matrix in WAG rats with normal blood vasopressin level and Brattleboro rats lacking endogenous vasopressin. In WAG rats, impaired osmotic concentration accompanied by an increase in the content of histochemically detectable glycosaminoglycans in the inner medullary interstitium was observed under conditions of NO synthesis blockade. In Brattleboro rats, NO synthesis inhibition, on the contrary, induced an antidiuretic response without significant changes in the renal extracellular matrix. These findings attested to a significant influence of NO on the urine concentration process. Morphofunctional changes in the kidneys under conditions of NO synthesis blockade are determined by blood vasopressin level.

[Evolution of mitral valve replacement]. / Évoliutsiia protezirovaniia mitral'nogo klapana.

Historical development of mitral valve surgery at Petrovsky Russian Research Center for Surgery is described in the article. Evolution of artificial heart valves design and development of surgical techniques are presented.

Endothelial and smooth muscle cells derived from human cardiac explants demonstrate angiogenic potential and suitable for design of cell-containing vascular grafts.

BACKGROUND: Endothelial and smooth muscle cells are considered promising resources for regenerative medicine and cell replacement therapy. It has been shown that both types of cells are heterogeneous depending on the type of vessels and organs in which they are located. Therefore, isolation of endothelial and smooth muscle cells from tissues relevant to the area of research is necessary for the adequate study of specific pathologies. However, sources of specialized human endothelial and smooth muscle cells are limited, and the search for new sources is still relevant. The main goal of our study is to demonstrate that functional endothelial and smooth muscle cells can be obtained from an available source-post-surgically discarded cardiac tissue from the right atrial appendage and right ventricular myocardium. METHODS: Heterogeneous primary cell cultures were enzymatically isolated from cardiac explants and then grown in specific endothelial and smooth muscle growth media on collagen IV-coated surfaces. The population of endothelial cells was further enriched by immunomagnetic sorting for CD31, and the culture thus obtained was characterized by immunocytochemistry, ultrastructural analysis and in vitro functional tests. The angiogenic potency of the cells was examined by injecting them, along with Matrigel, into immunodeficient mice. Cells were also seeded on characterized polycaprolactone/chitosan membranes with subsequent analysis of cell proliferation and function. RESULTS: Endothelial cells isolated from cardiac explants expressed CD31, VE-cadherin and VEGFR2 and showed typical properties, namely, cytoplasmic Weibel-Palade bodies, metabolism of acetylated low-density lipoproteins, formation of capillary-like structures in Matrigel, and production of extracellular matrix and angiogenic cytokines. Isolated smooth muscle cells expressed extracellular matrix components as well as α-actin and myosin heavy chain. Vascular cells derived from cardiac explants demonstrated the ability to stimulate angiogenesis in vivo. Endothelial cells proliferated most effectively on membranes made of polycaprolactone and chitosan blended in a 25:75 ratio, neutralized by a mixture of alkaline and ethanol. Endothelial and smooth muscle cells retained their functional properties when seeded on the blended membranes. CONCLUSIONS: We established endothelial and smooth muscle cell cultures from human right atrial appendage and right ventricle post-operative explants. The isolated cells revealed angiogenic potential and may be a promising source of patient-specific cells for regenerative medicine.

Role of the low-selective organic anion transport in regulation of osmotic balance of renal collecting duct principal cells under hypo-osmotic conditions.

In the course of adaptation of the rat kidney collecting duct cells to hypo-osmotic medium, the organic anion transporter inhibitor probenecid reduced significantly the regulatory cell volume decrease in response to a hypotonic shock. Both probenecid and hypotonic shock delayed significantly the entry into a cell of the fluorescent dye calcein, which exists as anion at neutral pH. Thus, the organic osmolyte transport plays an important role in the regulatory decrease of the principal cell volume under the hypo-osmotic conditions.

Fast Nongenomic Effect of Aldosterone on the Volume of Principal Cells in Collecting Tube and Genetic Heterogeneity of Epithelial Sodium Channel in the Postnatal Ontogenesis of Rat Kidney.

The effects of amiloride, epithelial sodium pump inhibitor, on the fast nongenomic effect of aldosterone in principal cells of an isolated segment of the distal portion of renal collecting tubes were studied in 10-day-old and adult rats. Fluorescent staining with Calcein AM showed various effects of amiloride (10(-5) M) on the stabilizing effect of aldosterone (10 nM) in hypotonic shock (280/140 mOsm/kg). Amiloride attenuated by 30% the effect of aldosterone on the amplitude of principal cell swelling in adult animals and almost completely abolished this effect in 10-day rats (p<0.05). These age-specific differences in the contribution of the distal portion of the collecting tube to the nongenomic effect of aldosterone did not depend on genetic heterogeneity of its α-subunit.

Regulation of V2 receptor by vasopressin is different in Brattleboro rats compared with Wistar.

This paper presents the new priority data on the effect of genetically determined deficiency of endogenous vasopressin on the functioning of V2 receptor in the plasma membrane of the principal cells of the collection ducts of Brattleboro rats. It was found that 2-day desmopressin administration results in the activation of V2 receptor gene expression in Brattleboro rat, whereas in Wistar rats the content of mRNA did not change. In addition, short-term exposure of the collection ducts of the kidneys to the hormone led to V2 receptor internalization from the plasma membrane in Wistar rats, but had no effect on the protein content in Brattleboro rats.

[Features of the immune proteasome expression in ascite Zajdela hepatoma after implantation into Brattleboro rats with the hereditary defect of arginine-vasopressin synthesis].

The expression of the total proteasome pool, immune proteasome subunits LMP2 and LMP7, TAP1 and TAP2 transporters, as well as RT1A molecule of MHC class I was investigated in the ascite Zajdela hepatoma at the 10th day after implantation into Brattleboro rats with the hereditary defect of hypothalamic arginine-vasopressin synthesis (AVP) and into WAG rats with normal AVP expression. In Zajdela hepatoma cells implanted into Brattleboro rats the 3-fold increase of the total proteasome pool and LMP2 level and 8-fold increase of the LMP7 level was detected by Western blotting as compared to those in WAG rats. Differences in the LMP2 and LMP7 expression suggest variations in their functions, namely the important role of LMP7 in anti-tumor immunity. The growth of Zajdela hepatoma in WAG rats was accompanied by the decreased level of total proteasome pool as well as immune proteasome expression as compared to those in Brattleboro rats during the regression of tumor. The analysis of TAP1 and TAP2 revealed the pronounced expression of these peptide transporters in Zajdela hepatoma cells implanted into Brattleboro and WAG rats. The expression level of RT1A molecule of MHC class I was increased 3 times in Zajdela hepatoma cells implanted into Brattleboro rats as compared to WAG rats. Moreover, flow cytometric analysis of CD4- and CD8-lymphocytes number in the spleen of Brattleboro and WAG rats was performed at the 10th day after implantation of Zajdela hepatoma. The increased number of CD4- and CD8-lymphocytes was observed in the spleen of Brattleboro as compared to WAG. The increased subpopulations of cytotoxic T-lymphocytes and T-helpers might promote the tumor regression in Brattleboro rats. The reduced populations of CD4- and CD8-lymphocytes in the spleen of WAG rats were accompanied by the splenomegaly and tumor progression. The data obtained suggest that AVP deficiency in Brattleboro rats leads to the increase of the immune proteasome and MHC class I expression in Zajdela hepatoma cells, resulting in tumor immunogenicity and its elimination by the adaptive immunity.

Role of epithelial sodium channel in the realization of homeostatic effects of aldosterone on the volume of principal cells of cortical collecting ducts in rats after hypoosmotic stress.

The mechanism of aldosterone effects (10 nM) on the volume of the principal cells of cortical collecting ducts after hypoosmotic stress (280/140 mOsm/kg) was studied using fluorescence microscopy. The experiments with intracellular fluorescent dye calcein showed that aldosterone significantly decreases the amplitude and rate of increase in principal cell volume during hypoosmotic stress. Epithelial sodium channel blocker amiloride (10(-5)M) significantly attenuated the effects of aldosterone on the amplitude and rate of changes in cell volume. The obtained data attest to the contribution of epithelial sodium channel to the realization of rapid non-genomic effects of aldosterone on the amplitude and rate of changes in volume of the principal cells of cortical collecting ducts in rat kidney after hypoosmotic stress.

[Expression of the RT1A molecule of the class I major histocompatibility complex in a Walker 256 tumor after transplantation into Brattleboro rats with a genetic defect of arginine-vasopressin synthesis].

The dynamics of expression of the RT1A antigen of the class I major histocompatibility complex (MHC) in a Walker 256 tumor after its transplantation into Brattleboro rats with a genetic defect of Arginine-Vasopressin synthesis in the hypothalamus was studied. Expression of the RT1A antigen was detected by means of Western-blotting and flow cytometry in the tumor cells on the 14th-17th days after transplantation. In addition, a simultaneous increase in the portion of cells that express the RT1A antigen and in the level of its expression per cell was observed. It is presupposed that at a deficiency of Arginine-Vasopressin, a renewal of expression of the class I MHC antigens, which results in an increase of immunogenicity of this tumor and regression, occurs in the Walker 256 tumor in the Brattleboro rats.

Effects of sodium diclofenac on the concentration function in animals with different neurohypophyseal status.

The characteristics of the osmotic concentration system under conditions of sodium diclofenac treatment were studied in Wistar rats with normally functioning vasopressin gene and homozygotic Brattleboro rats completely lacking endogenous vasopressin. Blockade of prostaglandin synthesis in rats with different neurohypophyseal status stimulated urinary osmolality to a different degree. Different contribution of sodium cations and urea to osmotic concentration was revealed.

Investigation on genetic heterogeneity of α-subunit of the epithelial sodium channel in rat renal cortex.

Genotypic variability of αENaC mRNA in adult rat kidney caused by deletion at the 3'-end of α-subunit DNA was studied by real-time PCR using specific probes with a fluorescent dye (TaqMan). It was found that mRNA deletion forms (a and b), products of alternative splicing of aENaC gene, are absent in the cortex of adult rat kidney.

Morphological characteristics of the inner medullary zone in the kidneys of Brattleboro and Wistar rats during blockade of prostaglandin synthesis.

Morphological characteristics of the inner medullary zone in the kidneys in Brattleboro and Wistar rats were studied during blockade of prostaglandin synthesis. The absence of a diuretic effect of prostaglandins on the kidneys was accompanied by structural changes in the transepithelial and interstitial barriers for an osmotic flow of water.

[The role of protein kinase C in the establishment of the mechanism of vasopressin antidiuretic action in the rat kidney during mammalian postnatal development].

The kidney of immaturely born mammals in early postnatal development is insensitive to the effect of the antidiuretic hormone, vasopressin. It has been demonstrated that water permeability of the epithelial cells in the collecting ducts of a rat kidney increases during development; in this process, the response to desmopressin, an agonist of vasopressin V2 receptors, appears at the age of 20 days. The observed increase in water permeability is connected with an increased content of the water channel's proteins aquaporins AQP2 and AQP3 in the plasma membrane. The calcium-dependent protein kinase C isoforms are the likely components of the vasopressin signal's transduction and are possibly involved in the mechanisms underlying the maturation of sensitivity to this hormone. The contents of three protein kinase C isoforms (alpha, delta, and zeta) in rats at different periods of their postnatal development were estimated using Western blot hybridization. It has been shown that the contents of protein kinase C isoforms alpha and delta increase with development, whereas the content of isoform zeta remains constant. The most likely participant of the mechanism providing for maturation of the cell's hormonal competence for vasopressin is the calcium-dependent protein kinase Ca, because it's content in the plasma membrane is maximal on days 20-24, which coincides with the time when the vasopressin action appears.

Involvement of interstitial structures of the kidney into hydrosmotic effect of vasopressin (morphofunctional study).

Administration of desmopressin for 4 days to homozygous Brattleboro rats lacking endogenous vasopressin induced an increase in osmotic concentration and was accompanied by typical changes in the morphofunctional state of interstitial cells of the renal papilla. These changes increase the permeability of extracellular matrix, which attested to the involvement of interstitial cells into hydrosmotic reaction to vasopressin.

[Results of treatment in patients with destructive pulmonary tuberculosis without consideration of drug sensitivity in Mycobacterium tuberculosis].

Treatment of 63 patients having infiltrative and disseminated pulmonary tuberculosis attended by decay and bacterial excretion with 4 essential drugs (isoniazid, rifadine, pyrazinamide, ethambutol) and, in disseminated processes, additionally with streptomycin without determining their drug sensitivity contributed to the cessation of sputum acid-resistant mycobacteria in 96.8% and to cavity cicatrisation in 77.8%. Irregular use of izoniazid and rifadine during continued treatment is one of the reasons for the low rates of cavity resolution.

[Function of transplanted heart].

Clinical and functional results of orthotopic cardiac transplantation are analyzed. It is demonstrated that case follow-up with special non-invasive methods (ECG, Holter monitoring, high-resolution ECG, EchoCG, dopler-EchoCG) is mandatory for detection of cardiac transplant function, early diagnosis of chronic rejection crisis, timely and optimal treatment tactics.

[Effect of vasopressin gene expression on the growth of Walker 256 carcinosarcoma in rats].

The growth pattern of the Walker 256 solid tumor has been studied in rats with different doses of the mutant vasopressin gene. In contrast to the vasopressin gene of normal WA rats, that of mutant Brattleboro rats has a deletion in the coding region that blocks expression at the translation level. The mutation is inherited as a recessive character and is expressed in homozygous Brattleboro rats as diabetes insipidus with an increased water consumption because of the absence of vasopressin in the blood. (WAG x Brattleboro) F1 hybrids have the same normal phenotype as WAG rats, including a low water consumption. Walker 256 carcinosarcoma, which is not strain-specific, intensely grows only in WAG and (WAG x Brattleboro) F1 rats. In these groups, the growth of the tumor leads to the animal death within approximately 30 days after the inoculation of tumor cells. In Brattleboro rats, the carcinosarcoma grows less intensely: the tumor node somewhat increases only within the first two weeks, after which the tumor began to decrease and eventually disappears altogether. Both characters exhibit a 100% concordance at the individual level.