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Biomedical subjects

B Jilma

Publications and source records attributed to B Jilma.

At least 91 records · Page 5Linked to original sources
PubMed1997

Effects of exercise on circulating vascular adhesion molecules in healthy men.

Based on previous studies showing an increase in circulating soluble intercellular adhesion molecule-1 (sICAM-1) after exercise, we hypothesized that exercise may also increase serum levels of the vascular cell adhesion molecule-1 (sVCAM-1) and sE-selection. In a prospective controlled clinical trial, serum levels of sE-selectin, sICAM-1 and sVAM-1 were measured before and after two different exercise protocols in healthy untrained men. Lactate levels increased up to 12.7 mmol/L (95% confidence interval: 10.1-15.9) and 3.6 mmol/L (CI: 2.4-4.7) after ergometry and after an one hour endurance exercise at 60% of the maximal work intensity, respectively (p = 0.028 vs baseline and controls). The maximal increase in lymphocyte counts of 106% (CI: 63-146), which was only of short duration, was higher immediately after ergometry as compared to that observed after endurance exercise (p = 0.028). However, the maximal increase in neutrophil counts of 178% (CI: 120-298) which was seen at 2 hours after endurance exercise was higher than that seen after ergometry (p = 0.028). In contrast, only small changes of circulating adhesion molecules were seen immediately after ergometry: sICAM-1 increased by 11% (CI: 4-25; p = 0.028), and similar tendencies were also observed for sVCAM-1 and sE-selectin. No other consistent and time-dependent changes of circulating adhesion molecules were observed and all differences and changes were < or = 11%. In sum our study provides evidence that recreational sporting activities in untrained healthy subjects at normal altitude have little influence on serum levels of the circulating vascular adhesion molecules sE-selectin, sVCAM-1 or sICAM-1.

Adult↗
PubMed1997

Effects of endothelin-1 on circulating adhesion molecules in man.

Several studies point to a role for endothelin-1 (ET-1) in enhancing adhesion molecule expression and leucocyte adhesion. We thus hypothesized that ET-1 would induce expression of adhesion molecules by endothelial cells and by leucocytes in humans, and hence compared with placebo the effect of a continuous 6-h ET-1 infusion on plasma levels of circulating (c)E-selectin, cP-selectin, intercellular and vascular cell adhesion molecule 1. In addition, we investigated the effects of ET-1 on expression of the leucocyte adhesion molecules CD11b/CD18 and L-selectin on monocytes and neutrophils. After an open pilot study to evaluate the safety of a 6-h ET-1 infusion of 0.4 pmol kg-1 min-1 (n = 4), the main study was conducted as a randomized, double-blind, two-way, cross-over trial in 12 additional young healthy male volunteers, who received the same treatment and were observed over a period of 24 h. ET-1 infusion decreased renal plasma flow by 43% (CI 35-51%; P < 0.001) and increased the filtration fraction by 80% (CI 20-110%; P < 0.001). Heart rate decreased by -10% (CI -4% to -15%) at 6 h under ET-1 infusion in the cross-over trial (P = 0.012 between periods). Although ET-1 infusions increased plasma levels of ET-1 by about 300%, ET-1 elicited no relevant changes in any circulating adhesion molecules or leucocyte adhesion molecules measured. In the placebo period small diurnal changes were observed for cP-selectin (-8%, CI -14 to -3%, P = 0.008) and cE-selectin (-6%, CI -10 to -3%, P = 0.003) at 12 h (20.45 h). In sum, ET-1 does not regulate circulating adhesion molecules in healthy men. Circadian variations may exist for plasma levels of cP-selectin and cE-selectin.

Adult↗
PubMed1997

Putative role of adhesion molecules in metabolic disorders.

Diabetes mellitus is associated with an increased risk of premature vascular disease. Vascular research is focusing on a potential role of adhesion molecules in diabetes mellitus, since classical risk factors including hyperlipidemia and hypertension do not completely account for the increased incidence of atherosclerosis in diabetes. After the expression of adhesion molecules on the cell surface, they are shed into plasma. Thus plasma concentrations of circulating adhesion molecules may be representative for endothelial activation, damage or turnover. Recently, evidence has been accumulating that increased plasma levels of adhesion molecules may predict cardiovascular disease, may be pathognomonic for diabetic microangiopathy or may even play a functional pathophysiologic role. The purpose of this article is to briefly summarise the role of (circulating) adhesion molecules in diabetes mellitus.

Cell Adhesion Molecules↗
PubMed1997

Effects of endothelin-1 (ET-1) on ocular hemodynamics.

PURPOSE: There is evidence from in vitro and animal data that endothelin-1 (ET-1) plays an important role in ocular blood flow. The aim of the present study was to investigate the effect of systemic ET-1 administration on ocular circulation in healthy subjects. METHODS: In a double blind, placebo-controlled, randomized, 2-way cross over study in 10 healthy male subjects, we administered stepwise, increasing doses of ET-1 (0 (saline), 1.25, 2.5 and 5.0 ng/kg/minutes; 20 minutes per dose (level) or placebo. Blood flow velocity in the ophthalmic artery as well as ocular fundus pulsations in the macula and the optic disc, and systemic hemodynamic parameters were measured. RESULTS: ET-1 dose-dependently reduced fundus pulsations in the macula (maximum effect -12 +/- 2% versus baseline; p < 0.001 versus baseline and placebo) and the optic disc (maximum effect: -19 +/- 5% versus baseline; p < 0.001 versus baseline and placebo), but did not affect blood flow velocity in the ophthalmic artery or systemic hemodynamics. CONCLUSIONS: Endothelin-1 reduces pulsatile blood flow in the choroid and the optic disc at doses which do not affect systemic hemodynamics or flow velocity in the ophthalmic artery. These results indicate that ocular circulation is particularly sensitive to changes in local ET-1 concentration and confirms the hypothesis that ET-1 may play a role in ocular vascular diseases.

Adult↗
PubMed1997

Does phosphodiesterase III inhibition reverse the cardiodepressive effects of propofol?

UNLABELLED: Propofol decreases arterial blood pressure as a result of reduced cardiac output and peripheral vasodilation, raising concerns about its safety in patients with impaired cardiovascular function. Phosphodiesterase III inhibitors (PDE-III-Inh) have gained attention as inotropic drugs. We therefore studied whether the cardiac effects of propofol could be abrogated by enoximone. Twenty-one patients with moderately reduced cardiac function scheduled for major surgery were allocated to this randomized, double-blind, placebo-controlled study. Measurement of cardiovascular data was performed before induction, 15 min after initiation of total intravenous anesthesia, 15 min after a first bolus of 0.25 mg/kg enoximone or placebo, and 15 min after a second bolus of 0.25 mg/kg enoximone or placebo. Propofol led to the expected reduction of cardiac output and bradycardia. Both doses of enoximone increased the cardiac index, reaching nearly preinduction values at a cumulative dose of 0.5 mg/kg enoximone. This change was primarily the result of significantly increased heart rate rather than increased ejection fraction or stroke volume index. Mean arterial pressure remained constant, which indicates uncompromised coronary perfusion pressure. Based on our results, we cannot recommend enoximone for the treatment of propofol-induced cardiac impairment. IMPLICATIONS: Total intravenous anesthesia with propofol is used increasingly in patients with impaired cardiac function. Enoximone, a drug suggested for congestive heart failure, had no effect on stroke volume or mean arterial pressure, but it increased heart rate. Enoximone is not recommended to treat impairment of cardiac function in patients anesthetized with propofol.

Adult↗
PubMed1997

Evidence against an effect of endothelin-1 on blood coagulation, fibrinolysis, and endothelial cell integrity in healthy men.

On the basis of an array of preclinical experimental results, it has been widely assumed that endothelin-1 (ET-1) may affect blood coagulation, fibrinolysis, and endothelial cell function, thereby playing a pathophysiological role in various cardiovascular diseases in humans. However, confirmation of this assumption is still lacking. ET-1 or placebo was administered intravenously to 12 healthy volunteers in a prospective, randomized, double-blind, crossover trial. Pathophysiologically relevant concentrations of ET-1 (an approximate threefold increase of normal blood levels) causing hemodynamic effects were reached by continuous intravenous infusion for 6 hours. Components of the coagulation (thrombin-antithrombin complexes, prothrombin fragment F1 + 2, activated factor VII, and factor VII antigen) and fibrinolytic (fibrin split product D-dimer, plasmin-plasmin inhibitor complex, tissue-type plasminogen activator, urokinase-type plasminogen activator, and plasminogen activator inhibitor-1) systems and markers of endothelial cell perturbation/dysfunction (von Willebrand factor and thrombomodulin) were measured before the start of infusion and after 2, 6, 12, and 24 hours. Comparing changes in the plasma concentrations of these parameters during and after infusion of ET-1 and placebo, we found no specific effects of ET-1. In contrast to previous reports from preclinical experiments, ET-1 does not appear to affect coagulation or fibrinolysis, nor does this peptide induce relevant endothelial cell perturbations in humans.

Adult↗
PubMed1997

Persistent elevation and metabolic dependence of circulating E-selectin after delivery in women with gestational diabetes mellitus.

The increased risk of premature atherosclerosis in noninsulin-dependent diabetes mellitus (NIDDM) might be related in part to augmented expression of endothelial adhesion molecules (AMs). So far it is, however, unknown whether increased circulating (c) AMs in NIDDM are only a consequence of this disease or also involved in its sequelae. To determine the presence of cAMs in a population at increased risk for subsequent development of NIDDM, we analyzed fasting and postprandial [oral glucose tolerance test (OGTT): 100 g] serum concentrations of circulating E-selectin, vascular cell adhesion molecule-1 (cVCAM-1), and intercellular adhesion molecule-1 (cICAM-1) in pregnant women with either gestational diabetes (GDM) or normal glucose tolerance (NT) before and after delivery vs. nonpregnant healthy women (C). During pregnancy cE-selectin and cVCAM-1 were elevated in both GDM and NT vs. nonpregnant females (P < 0.01 vs. C). Following delivery, all GDM females regained normal glucose tolerance according to OGTT criteria, but showed slightly higher postprandial [area under the curve (AUC)180 min] glycemia and HbA1c values than nonpregnant healthy women (P < 0.05), indicating persisting subtle abnormalities in carbohydrate metabolism. cE-selectin and cVCAM-1 remained increased in GDM (P < 0.01 vs.C) after delivery, but fell to normal in NT (P < 0.05 before vs. after delivery). Furthermore, a correlation was seen in GDM females between cE-selectin and HbA1c (P < 0.005), fasting glucose (P < 0.01), and insulin (P < 0.05) as well as postprandial (AUC180 min) glucose and insulin concentrations (P < 0.05) during OGTTs, both before and after delivery. ICAM-1, however, did not differ significantly between groups. In summary, GDM is characterized by persistently raised levels of cE-selectin and cVCAM-1 12 weeks after delivery. Whether these persistent elevations of cE-selectin and cVCAM-1 reflect early vascular injury or represent a risk factor for atherosclerosis in women at increased risk for NIDDM remains to be determined.

Adult↗
PubMed1997

Partial blockade of nitric oxide synthase blunts the exercise-induced increase of von Willebrand factor antigen and of factor VIII in man.

BACKGROUND: Until now the effects of beta-adrenergic agonists have largely been ascribed to their ability to induce intracellular formation of cyclic adenosine monophosphate. Recently evidence has been accumulating that at least some beta1 and beta2-adrenoceptor effects may be mediated by nitric oxide (NO). Based on these studies, we hypothesized that the beta-adrenoceptor mediated increase of von Willebrand factor and factor VIII-activity (FVIII:C) in plasma during exercise, is caused by an NO-dependent mechanism. METHODS: Thirteen young healthy subjects finished an exhaustive bicycle exercise protocol while they were infused placebo or the NO-synthase inhibitor N-monomethyl-L-arginine (L-NMMA) on two separate days in a randomized, double blind cross-over design. FINDINGS: During exercise systemic haemodynamic changes were parallel in both treatment periods, but L-NMMA caused a partial inhibition of NO-synthase as evidenced by a 30% decrease in exhaled NO. The workload capacities were not different during L-NMMA or placebo infusion. However, under placebo treatment exercise increased vWF-Ag by a maximum of 61% (CI: 43-84; p = 0.002) and FVIII:C by 44% (CI: 31-59; p = 0.001), which was significantly attenuated when subjects were treated with L-NMMA (p <0.05): under L-NMMA treatment vWF-Ag increased by only 25% (CI: 5-51; p = 0.001) and FVIII:C by 12% (CI: 6-39; p = 0.001). INTERPRETATION: Partial blockade of NO-synthase with L-NMMA blunts the exercise-induced increase in vWF-Ag and FVIII:C. Our trial points to a role of endogenous NO-generation in the beta2-adrenergic increase in vWF/FVIII. Thus, we propose that physiologic processes which are induced by systemic beta2-adrenoceptor stimulation may at least partly be mediated by NO.

Adult↗
PubMed1996

Sex differences in concentrations of exhaled nitric oxide and plasma nitrate.

Nitric oxide (NO) is generally considered as an endogenous vasoprotective agent. Various studies indicate that the female sex hormone estradiol, that contributes to the well known gender differences in cardiovascular disease, may enhance NO-production. Thus we studied sex differences in NO-generation by measuring single breath NO-exhalation and plasma levels of nitrate (NO3), the stable endmetabolite of NO. In this observational trial 22 male and 21 female volunteers, 19 to 38 years of age, were studied on 3 days at weekly intervals. Median concentrations of NO were 20 parts per billion (95% CI: 16 to 32 ppb) in women and 34 ppb (95% CI: 31 to 58 ppb) in men. The median plasma concentrations of NO3 were 14 microM/L (95% CI: 11 to 23 microM/L) in women and 27 microM/L (95% CI: 24 to 47 microM/L) in men. Thus, men exhaled 59% more NO (p < 0.001) and had 99% higher NO3 levels than women (p < 0.0001). Even when exhaled NO concentrations were corrected for body weight, men exhaled 50% more NO than women (p = 0.024). No significant changes in measured endpoints were seen during the menstrual cycle (p > 0.05) in women. In view of the diversity of NO-actions, the finding of marked sex differences in NO-production is basic to the elucidation of gender differences in a number of (patho)-physiologic conditions.

Adult↗
PubMed1996

Effects of desmopressin on circulating P-selectin.

Von Willebrand factor (VWF) and P-selectin share an identical intracellular storage compartment and transport to the cell surface. We induced degranulation of the Weibel-Palade bodies and measured circulating (c)P-selectin in plasma to test whether soluble P-selectin is present in the Weibel-Palade bodies, or if P-selectin bound to the cell membrane of endothelial cells (EC) is rapidly proteolytically cleaved in vivo. A dose of 0.3 microgram/kg of desmopressin (DDAVP) or placebo was infused over 30 min to eight healthy men in a double-blind cross-over study. Plasma levels of cP- selectin and VWF-Ag were followed for 24 h. Despite a twofold increase in VWF-Ag levels immediately after a 2 h after infusion of DDAVP, no significant change in plasma concentrations of cP-selectin were observed. In summary, degranulation of the Weibel-Palade bodies is an unlikely source of cP-selectin. Thus cP-selectin in healthy subjects is conceivably attributable to other mechanisms, such as minor degrees of platelet activation or transcription induction of an alternatively spliced P-selectin.

Adult↗
PubMed1996

Improved characteristics of aPC-resistance assay: Coatest aPC resistance by predilution of samples with factor V deficient plasma.

Screening for a resistance against activated protein C (aPCR), which is in most cases caused by FV:Q506 mutation, is performed by functional tests measuring the effect of aPC on activated partial thromboplastin time (aPTT). Because of an insufficient discrimination between FV:Q506 mutation negative and positive individuals with the first generation of the functional test Coatest aPC Resistance (Chromogenix AB, Mölndal, Sweden), the definition of an arbitrary cut-off level was only possible using the results of DNA analysis. The use of an arbitrary cut-off level still resulted in unsatisfactory low sensitivity and specificity for the functional test. Thus, time- and cost-consuming DNA analyses had to be performed frequently to establish the diagnosis. The objective of this study was to evaluate an improved version of this assay that uses predilution of samples with factor V deficient plasma containing a heparin neutralizer. Using the data from 32 FV:Q506 mutation positive and 55 mutation negative individuals, the authors calculated a cut-off value resulting in an enhanced sensitivity (0.91 versus 1.0) and specificity (0.77 versus 1.0) compared to the old one. Imprecision was lowered from 5.36% (first generation) to 2.43%, in particular in samples with longer clotting times. In patients with prolonged aPTT, either caused by therapy with oral anticoagulants or heparin, correct results were obtained with the second generation assay, in contrast to the first generation assay. With this second generation assay the number of DNA analyses can be substantially reduced.

Adult↗
PubMed1996

Effects of estradiol on circulating P-selectin.

The membrane protein P-selectin tethers leukocytes to endothelial cells (EC) and on activated platelets, and may play a role in atherosclerosis. Lower plasma levels of a soluble (c) P-selectin have recently been observed in premenopausal women compared to those in men. Given the antiatherogenic-cardioprotective effect of 17 beta-estradiol (E2), we hypothesized that E2 may down-regulate the expression of P-selectin and subsequently decrease cP-selectin levels. The effects of E2 on levels of plasma cP-selectin were evaluated during the menstrual cycle in healthy women (n = 18) and by measuring the effect of a single im injection of 10 mg E2 valerate (n = 9) or placebo (n = 10) on cP-selectin levels in healthy male volunteers. In women, the cyclic increase in serum E2 concentrations was accompanied by a decrease in cP-selectin levels from 110 ng/mL [95% confidence interval (CI), 100-137 ng/mL] in the follicular phase. The decrease reached a maximum of 13% (95% CI, 2-19%, P = 0.014) in the luteal phase. In men, cP-selectin decreased from a median of 139 ng/mL (95% CI, 113-165) to 125 ng/mL (95% CI, 97-152; P = 0.038) 4 days after E2 injection. The median baseline value of cP-selectin in the 19 male volunteers was 133 ng/mL (95% CI, 115-143 ng/mL) and was approximately 30% higher than those in the female volunteers during the midcycle (P = 0.024) and luteal (P = 0.012) phases, but was not different from that during the follicular phase. In sum, our study suggests that E2 lowers cP-selectin levels. An E2-induced decrease in cP-selectin reflects either decreased activation or damage of platelets and/or endothelial cells in vivo. Thus, our study may point to an additional mechanism for the residual antiatherogenic-cardioprotective effect of E2 that cannot be explained by its lipid-lowering effects.

Adult↗
PubMed1996

Elevated circulating P-selectin in insulin dependent diabetes mellitus.

Based on findings that showed increased P-selectin expression on platelets and on choroidal microvessels of patients with insulin dependent diabetes mellitus (IDDM), we hypothesized that also plasma concentrations of circulating (c)P-selectin would be increased in these patients. The aim of this study was to compare the plasma levels of cP-selectin between non-smoking patients with IDDM, treated with an intensified insulin therapy, and healthy controls. The study design was prospective, cross-sectional and analyst-blinded. Subjects were matched individually for sex, age and body mass index. Plasma levels of cP-selectin and of von Willebrand antigen (vWF-Ag) were determined by enzyme linked immunoassays. Forty-two pairs were available for intergroup comparison. Median plasma concentrations of cP-selectin in patients with IDDM (285 ng/ml; interquartile range: 233-372) were on average 21% higher than those of controls (236 ng/ml; interquartile range: 175-296; p = 0.004). Also, median plasma levels of vWF-Ag were 10% higher in patients (96 U/dl; interquartile range: 82-127) than controls (87 U/dl; interquartile range: 70-104; p = 0.025). There was no correlation between plasma concentrations of cP-selectin and vWF-Ag levels in either group (p > 0.05). In conclusion, our results of increased cP-selectin levels are in line with increased P-selectin expression on platelets and on choroidal microvessels found in patients with IDDM. In view of the currently developed small molecule inhibitors of cell adhesion molecules, these independent observations together may provide a sound rationale to select P-selectin as a target for treating or preventing IDDM-associated micro- or macrovascular complications.

Adolescent↗
PubMed1996

Influence of angiotensin II on circulating adhesion molecules and blood leukocyte count in vivo.

The mechanism of the beneficial effect of angiotensin converting enzyme inhibitors in patients with myocardial infarction is not clear. Recent in vitro data indicate that angiotensin II (AII) stimulates the expression of adhesion molecules and thus activates leukocyte endothelial interactions. In eight healthy volunteers we investigated the influence of exogenous AII on circulating adhesion molecules and on the blood leukocyte count. A systemically effective and a systemically ineffective dose of AII were administered intravenously over 4 h in a single blind crossover design. Examination of the time course of circulating intercellular and vascular adhesion molecules and E-selectin (cICAM-1, cVCAM-1, cE-selectin-1) in response to the AII infusion revealed increases of up to 11% (especially in cVCAM-1 levels) at single time points, but no significant sustained elevation or trend that can be interpreted as a drug-induced effect. The systemically effective dose, which induced an increase in mean arterial blood pressure from 80 to 108 mmHg (1 mmHg = 133.3 Pa), resulted in a significant increase in blood leukocytes, from 4.8 +/- 0.3 to 5.5 +/- 0.3 g/L (p < 0.05); the systemically ineffective AII dose did not alter blood leukocyte count significantly. Although we did not find an influence of AII on circulating adhesion molecules in vivo, we observed an increase in the blood leukocyte count; thus it may be intriguing to assess whether renin-angiotensin system modulating drugs might exert their favorable effect in ischemic diseases at least in part via an influence on leukocytes.

Adult↗
PubMed1994

Effects of neuropeptide Y and vasoactive intestinal peptide on human venous smooth muscle in vivo.

The direct and noradrenaline-modulating effects of neuropeptide Y (NPY) and vasoactive intestinal peptide (VIP) on venous smooth muscle were studied in healthy volunteers employing the dorsal hand vein compliance technique. Local infusions of NPY had no measurable effect on venous tone, but coinfusion of a constant high dose of NPY (242 pmol/min) with noradrenaline caused a 2.9-fold increase in the mean ED50 for noradrenaline. The dilating effect of VIP on preconstricted hand veins was weak, maximal venodilation could not be achieved, because systemic side effects occurred at submaximally venodilating doses. Coinfusion of noradrenaline with a weakly venodilating, constant dose of VIP (93.2 pmol/min) caused a 0.5-fold decrease in the sensitivity for noradrenaline. Although functional interactions between NPY or VIP and noradrenaline could be demonstrated, the dosages of the peptides required were high. Thus our results indicate that neither NPY nor VIP exert a major direct or noradrenaline-modulating effect on human veins.

Adult↗
PubMed1994

Studies on the effect of short-term oral dihydroergotamine and troxerutin in patients with varicose veins.

OBJECTIVE: To evaluate the clinical efficacy and pharmacologic effects of dihydroergotamine and troxerutin on varicose veins. METHODS: A double-blind, randomized, placebo-controlled parallel-group study was conducted in 53 patients with primary varicose veins. Patients received either a fixed combination of 3 mg dihydroergotamine and 300 mg troxerutin three times a day or placebo for 3 weeks. Symptomatic improvement was assessed by a self-assessment score, venocontracting effects on a varicose vein were quantified by the venous compliance technique (VCT), and changes in venous dysfunction were measured by digital photoplethysmography (DPPG). RESULTS: A significant reduction (p < 0.01) of subjective symptoms was observed in both groups. Results from VCT and DPPG after the therapy with dihydroergotamine and troxerutin or placebo were not significantly different (p > 0.05) from pretreatment values. Furthermore, no significant intergroup difference was observed when the before- and after-therapy differences of values of the self-assessment scores (VCT and DPPG) were compared. CONCLUSION: In our study, 3 weeks of treatment with a fixed drug combination of 3 mg dihydroergotamine plus 300 mg troxerutin three times a day had no measurable effect compared with placebo on any of the evaluated end points.

Adult↗