Direct stimulatory effect of ethanol on 17 alpha-hydroxylase activity of rat testis interstitial cells

These studies examined the in vitro effects of ethanol on the activities of steroidogenic enzymes involved in the conversion of progesterone to testosterone in 10,000xg supernatants of rat testis interstitial cells. 17 alpha-Hydroxylase activity of interstitial cells increased in direct relation to the final concentration of ethanol added (2.2 - 652 mM); however, 17,20-lyase and 17-ketosteroid reductase activities were not affected. These studies, together with a previous study, where we showed that testosterone accumulation by intact interstitial cells was inhibited by ethanol when either progesterone or 17 alpha-hydroxyprogesterone (but not androstenedione) were added as exogenous substrates, suggest that ethanol, in addition to stimulating 17 alpha-hydroxylase activity, inhibits the normal coupling of 17, 20-lyase activity with the 17-ketosteroid reductase activity.     

The effect of ethanol on the bile-secreting function of the liver in rats

The effect of long-term application of ethanol on the biochemical composition of rat bile has been studied. These results have been compared with the changes of activity of hepatic microsomal enzymes and ultrastructure of hepatocytes. The changes of biliary lipid synthesis and secretion have been shown to reflect the change of microsomal metabolic functions and to be accompanied by liver destruction processes.     

The effect of bile salts on human vascular endothelial cells

The uptake and release of radiochromium from adult human vascular endothelial cells in culture was employed to determine the relative toxicity of different bile salts. Endothelial cells after pre-incubation with 51Cr for 18 h were incubated with bile salts for 24 h and percentage chromium release was taken as a measure of toxicity to cells. Lithocholic acid (LC) (potassium salt) was cytotoxic at concentrations greater than 50 microM. However, LC glucuronide, sulfate and the beta-epimer were progressively less toxic with toxicity seen at concentrations of 60, 110 and 180 microM, respectively. The greatest cytotoxic effect was observed with glycolithocholic acid (GLC) (potassium salt) which was toxic at every concentration tested (20-200 microM). Sulfation abolished the toxic effect of GLC. At the concentrations employed for the assay (between 20 and 240 microM) GLC sulfate (disodium salt), taurolithocholic acid sulfate (disodium salt), cholic acid (sodium salt), glycocholic acid (sodium salt), deoxycholic acid (sodium salt) and ursodeoxycholic acid (sodium salt) were not cytotoxic. The 51Cr release cytotoxicity assay was validated with lactate dehydrogenase leakage from endothelial cells with a good correlation (r = 0.87). These data confirm in a human cellular system that LC and its conjugates were the most toxic of the bile salts tested and explains its pathophysiological importance in hepatobiliary disease. It also suggests that biotransformation by either sulfation or beta-epimerisation of bile salts especially of LC, as occurs in patients with intrahepatic or extrahepatic biliary obstruction or severe cholestasis, is hepatoprotective.     

Direct effect of gonadotropins on decidualization of human endometrial stromal cells

Decidualization of stromal cells isolated from proliferative human endometrium was achieved by adding to the culture medium human gonadotropins (FSH, FSH + LH, hCG). In addition to changes in the morphology of the stromal cells to the decidual phenotype, decidualization was evident from the expression of prolactin (PRL), demonstrated immunocytochemically, by Western blotting analysis, and by measuring its output into the medium through solid phase enzyme immunoassay. Gonadotropins also induced cAMP formation in the endometrial stromal cells under the same experimental conditions. This finding suggests that the mechanism by which gonadotropins promote decidualization of human endometrial stromal cells in vitro involves the introduction of cAMP, a compound that we have found to elicit the expression of PRL in this system. PRL is likely to be a key intermediate in the process of decidualization since it is by itself capable of inducing differentiation of the endometrial stromal cells to the decidual phenotype. Awareness of direct actions of gonadotropins on the endometrial cells and, in particular, of the decidualizing effects of FSH (Metrodin), FSH + LH (Pergonal) and hCG may contribute to the understanding of physiologic as well as pathophysiologic conditions relevant to endometrial functions and fertility.     

Effects of chronic sympathectomy on vascular function in the human forearm.

To determine whether endothelial function is altered by chronic surgical sympathectomy, we infused ACh, isoproterenol, nitroprusside (NTP), and the nitric oxide synthase inhibitor NG-mono-methyl-L-arginine (L-NMMA) into the brachial arteries of nine patients 5-64 mo after thoracic sympathectomy for hyperhidrosis. Age- and gender-matched controls were also studied. Forearm blood flow (FBF) was measured by venous occlusion plethysmography. Lower body negative pressure was used to assess reflex vasoconstrictor responses. Tyramine, which acts locally and causes norepinephrine release from sympathetic nerves, was also administered via the brachial artery. FBF at rest was 2.5 +/- 0.4 ml x dl-1 x min-1 in the patients and 2.5 +/- 0.3 ml x dl-1 x min-1 in the controls (P = 0.95). The normal vasoconstrictor responses to lower body negative pressure were abolished in the patients. By contrast, tyramine produced dose-dependent vasoconstriction in the patients that was identical to that of controls. The dose-response curves to ACh were similar in patients and controls, with maximum values of 19.3 +/- 4.4 vs. 25.5 +/- 2.8 ml x dl-1 x min-1, respectively. L-NMMA reduced baseline FBF similarly and reduced the maximal FBF response to ACh in both groups (patients 8.9 +/- 3.5 vs. controls 9.7 +/- 2.5 ml x dl-1 x min-1). The vasodilation to isoproterenol was similar and blunted to the same extent in both groups by L-NMMA. The responses to NTP in patients and controls were similar and not affected by L-NMMA. We conclude that, in humans, chronic surgical sympathectomy does not cause major disruptions in vascular function in the forearm. The normal vasoconstrictor responses to tyramine indicate that there were viable sympathetic nerves in the forearm that were not engaged by LBNP.     

The effect of chronic ethanol on glutamate binding in human and rat brain

Quantitative autoradiographic techniques demonstrate that chronic alcohol administration causes a decrease in [3H]-glutamate binding to hippocampal N-methyl-D-aspartate (NMDA) receptors. A 14% decrease in [3H]-glutamate binding in the hippocampal CA1 region is seen both in the rat after five days of ethanol administration and in postmortem hippocampal tissues from alcoholics. In the rat, 24 hr ethanol withdrawal values are intermediate between control and alcohol binding levels. There was no significant effect of ethanol on [3H]-glutamate binding in the cortex or caudate.     

Genetics and cardiovascular system: influence of human genetic variants on vascular function

Candidate gene association studies in cardiovascular diseases have provided evidence on the molecular basis of phenotypic differences between individuals. The comprehension of how inherited genetic variants are able to affect protein functions has increased the knowledge of how genes interact with environment in order to modulate a particular phenotype. Although it is known that the human genome contains more than 10 million SNPs, only a minor part of them are supposed to be functional. A causative SNP in a particular gene may confer a small to moderate effect in complex phenotypes, such as functions important to cardiovascular homeostasis. This paper is a selective review of the literature on the evidence for interactions between vascular function and naturally occurring genetic variants in endothelial nitric oxide synthase (eNOS) and beta-2 adrenergic receptor (ADRB2), two genes among those influencing vascular phenotype and examples for which there is a strong evidence base. eNOS and ADRB2 will be characterized, as well as the mechanisms by which the enzyme and the receptor work to control vascular responses will be described. Understanding the molecular mechanisms underlying gene-mediated vascular function and their modification by genetic variants is expected to result in a better comprehension about individual's phenotypic differences.     

Methylmercury-injury effect on tube formation by cultured human vascular endothelial cells

The effect of methylmercury chloride (MeHg) on growth and tube formation by cultured human umbilical vein endothelial cells (HUVECs) was investigated. HUVECs were collected by enzymatic digestion with collagenase. Precultivation of HUVECs with MeHg at concentrations of 1.0–50.0 mol/L exerted negligible effects on the viable cell number, while the viable cell number was slightly reduced at 100 mol/L and fell to zero at concentrations exceeding 500.0 mol/L MeHg. The viable cell number was depressed in a concentration-dependent manner. Tube formation was studied by culturing the cells on gelled basement membrane matrix (Matrigel). Treatment of HUVECs with 0.1–5.0 mol/L MeHg for 24 h inhibited tube formation dose-dependently. Fetal bovine serum (FBS) increased tube formation in a dose-dependent manner, with half-maximum stimulation of tube formation at approximately 3.4% FBS. The length of tube formation decreased time-dependently at concentrations of 0.1 and 1.0 mol/L MeHg. Pretreatment of Matrigel with 1 mol/L MeHg before the cell seeding reduced the tube formation by HUVECs. These results suggest that the growth and tube formation by HUVECs is susceptible to MeHg cytotoxicity, and that MeHg could be injurious to endothelial cell function.Abbreviations MeHg methylmercury chloride - HUVECs human umbilical vein endothelial cells     

The excitotoxic effect of NMDA on human lymphocyte immune function

N-Methyl-d-aspartate (NMDA)-activated glutamate receptors are expressed in lymphocytes, but their roles have not yet been defined. We show that incubation of human peripheral blood lymphocytes with NMDA resulted in increased intracellular calcium and reactive oxygen species (ROS) levels through effects on NMDA-activated glutamate receptors. In terms of ROS production, T cells were most affected, followed by NK cells, whereas B cell ROS levels were not increased. In unstimulated T and NK cells, interferon-gamma (IFN-gamma) production was unaffected by NMDA, whereas interleukin-2 stimulation of IFN-gamma production was significantly suppressed by NMDA. Simultaneous incubation of the cells with NMDA and IL-2 resulted in a dramatic increase in the amount of cells expressing the NR1 subunit of the NMDA-activated receptors. We conclude that NMDA-activated glutamate receptor activation, accompanied by the changes in intracellular calcium and ROS levels, may be involved in the modification of immune functions of human T and NK cells.     

The inhibitory effect of ethanol on ethanol production by Zymomonas mobilis

Summary In an effort to establish the reasons for the limitations in the final ethanol concentration of Zymomonas mobilis fermentation, the effects of CO₂ and ethanol on the fermentation were investigated using continuous and fed-batch cultivation systems. The nucleation and stripping out of CO₂ from the fermenter using diatomaceous earth or nitrogen gas or both exhibited a profound effect on the glucose uptake rate during the early stages of fed-batch fermentation, but did not improve final ethanol yields. The addition of ethanol together with above mentioned experiments confirmed conclusively that ethanol inhibition is responsible for the final ethanol concentration obtainable during Zymomonas mobilis fermentation. The final concentration lies between 90 and 110 gl⁻¹ or approximately 12–15% (v/v) ethanol.     

Regulating effect of bone marrow cells on human T-lymphocyte function

A study was made of the regulatory effect of human bone marrow cells in two experimental systems: lymphocyte proliferation in response to PHA, and spontaneous and PHA-induced production of macrophage migration inhibition factor (MIF) by peripheral blood lymphocytes. It was shown that bone marrow cells inhibit the proliferative activity of stimulated peripheral blood lymphocytes and induced MIF production. The effect of bone marrow cells on spontaneous MIF production was found to be inconclusive.     

In vitro effect of actinomycin D on human neutrophil function

The effect of actinomycin D (ACT-D) on human neutrophil chemotaxis, chemiluminescence (CL), superoxide (O2-) production, phagocytic uptake, and intracellular bacterial killing has been examined. The viability of the ACT-D-treated neutrophils was 98% even at a concentration of 10 micrograms/ml for 4 hr. Using fMLP as the chemotactic factor, depressed chemotaxis was demonstrated following ACT-D (1-10 micrograms/ml) pretreatment of neutrophils as compared with the non-treated controls. Similar ACT-D pretreatment produced the depressed responses in phorbol myristate acetate-induced CL and superoxide production by neutrophils. Moreover, using heat-inactivated human serum as an opsonin for Salmonella enteritidis (NCTC 6676), there was a significant difference in intracellular killing (P less than 0.01) but no difference in phagocytic uptake between ACT-D-treated and non-treated neutrophils. These studies indicate that ACT-D profoundly impairs both intracellular bacterial killing by human neutrophil through an effect on respiratory burst activity and directed cell migration of human neutrophils.     

Chronic ethanol exposure in the embryonic chick heart: effect on myocardial function and structure

To investigate the effect of chronic ethanol exposure on the embryonic chick heart, chick embryos were exposed daily to one of seven graded doses of ethanol or to saline only (shams) from 0 to 96 hr of incubation. One hour before and after exposure at 72 hr, and 1 hr before and after exposure at 96 hr, embryos were analyzed for changes in heart function, embryo tissue ethanol content, occurrence of anomalies, and embryo weights. At both 71 and 73 hr of incubation (during cardiogenesis), when compared to shams, heart rate (HR) in embryos receiving ethanol doses greater than 0.0375 ml increased significantly (P less than .05) with commensurate increases in injected ethanol. Additionally, at 73 hr, depressed cardiac contractility, measured as shortening fraction, was noted at doses greater than or equal to .0375 when compared to shams. While slight increases in shortening fraction (SF) across dose were noted at 95 and 97 hr, only random doses were statistically significant from shams, with no specific trend in either HR or SF at this postcardiogenesis stage. Within each time group, gas chromatography analysis of embryo tissue ethanol content demonstrated a linear relationship between dose injected and tissue ethanol content retrieved. With increasing dose and stage, viability decreased. Weights of ethanol-injected embryos were not significantly different from shams within each time group. Our studies of the response of the embryonic chick heart to ethanol indicate both dose and stage susceptibility, with greater susceptibility to ethanol injury during active cardiogenesis.     

Somatostatin receptor subtype expression and function in human vascular tissue

In animal models the somatostatin analog angiopeptin inhibits intimal hyperplasia by acting primarily through somatostatin receptor 2 (SSTR-2). However, the results of clinical trials using angiopeptin have been disappointing. In this study we showed that human blood vessels express high levels of SSTR-1 with significantly lower levels of SSTR-2 and -4. Samples of normal veins and arteries, as well as atherosclerotic arteries, expressed predominantly SSTR-1. In addition, the levels of SSTR-1 varied between individuals, indicating that the vascular disease process may have affected SSTR gene expression. Immunocytochemical studies demonstrated that SSTR-1 was present in endothelial but not vascular smooth muscle cells. No evidence of SSTR-3 or -5 expression was detected in normal or diseased blood vessels. Two endothelial cell preparations, ECV304 and human umbilical vein endothelial cells, were investigated and shown to express only SSTR-1 and -4. Exposure of these cells to 10 nM somatostatin or 10 nM SSTR-1-specific agonist resulted in alterations to the actin cytoskeleton, as characterized by a loss of actin stress fibers coupled with an increase in lamellipodia formation at the plasma membrane. These results suggest that the lack of effectiveness of angiopeptin in humans may be due to the differential expression of SSTR-1 by human endothelial cells.