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Biomedical subjects

Z S Herman

Publications and source records attributed to Z S Herman.

At least 37 records · Page 2Linked to original sources
PubMed1999

Effect of a hemodialysis session on plasma levels of endothelin-1 in hypertensive and normotensive subjects with end-stage renal failure.

BACKGROUND: Elevated plasma endothelin-1 (ET-1) was found in end-stage renal failure (ESRF). However, there are discordant reports on the influence of hypertension on plasma ET-1 in ESRF and on the effect of hemodialysis on ET-1 concentrations. AIM: To compare the time course of plasma ET-1 during hemodialysis in hypertensive (HT) and normotensive (NT) ESRF patients. METHODS: Plasma ET-1 and mean blood pressure (MP) were measured in 12 HT patients and 11 matched NT patients on maintenance hemodialysis at baseline (B), after a 2.5-3.5 h hemodialysis with ultrafiltration (P1) and after a subsequent 1 h isovolumic dialysis (P2). RESULTS: In HT patients, plasma ET-1 increased at P1 with no further change after P2 (B vs. P1 and P2, p < 0.05). In NT patients, ET-1 levels were similar at B, P1 and P2. In HT, but not in NT subjects, volume loss correlated with change of ET-1 at P1. In HT patients, MP fell during P1 and tended to return towards baseline at P2. In NT patients, MP dropped after P1 and remained lower also at P2. CONCLUSION: Hypertensive ESRF subjects exhibit potentiated ET-1 release on hemodialysis, possibly stimulated by volume depletion with sympathetic activation, which may attenuate hypotensive hemodialysis effects thus contributing to hypertension in ESRF.

Adult↗
PubMed1999

Interactions between the neuropeptide Y system and the hypothalamic-pituitary-adrenal axis.

The aim of this paper is to review the present knowledge of interactions between the neuropeptide Y (NPY) system and the hypothalamic-pituitary-adrenal (HPA) axis. On the basis of in vitro and in vivo studies of various animal species, we review the effects of NPY on all levels of HPA axis activity. We also describe the effects of glucocorticosteroids on the NPY system in the hypothalamus, including interactions between glucocorticosteroids and insulin. On the basis of available literature, we discuss the role of these interactions in the control of food intake and in the pathogenesis of obesity.

Animals↗
PubMed1998

Effects of fenofibrate on plasma cytokine concentrations in patients with atherosclerosis and hyperlipoproteinemia IIb.

BACKGROUND AND OBJECTIVE: In recent studies atherosclerosis has often been referred to as immune disease. The atherosclerotic plaque consists of large amounts of inflammatory cells, mainly monocytes/macrophages and T lymphocytes. Macrophages activated by low-density lipoproteins (LDL) secrete tumor necrosis factor alpha (TNF-alpha) and interleukin-1 (IL-1) in vitro, while LDL-stimulated T lymphocytes release interferon gamma (IFN-gamma). The aim of this study was to estimate the plasma levels of TNF-alpha, IL-1, IFN-gamma in patients with hyperlipoproteinemia IIb (HLPIIb) and atherosclerosis. Since the fibrates are drugs of choice in HLPIIb, we additionally evaluated the effect of fibrates on the cytokine levels. METHODS: Ten patients with HLPIIb were treated with micronized fenofibrate for 1 month. Before and after treatment, the cytokine levels were measured by the ELISA method. To accurately evaluate cytokine levels, we excluded atherosclerotic patients and control subjects with any inflammatory disease. RESULTS: The initial lipid parameters were as follows: total cholesterol (TC): 6.9 +/- 0.24 mmol/l, triglycerides (TG): 3.44 +/- 0.53 mmol/l, LDL: 4.35 +/- 0.12 mmol/l, and apolipoprotein B (ApoB): 1.62 +/- 0.05 g/l. After 1 month of fenofibrate treatment the parameters decreased to the following values: TC 5.36 +/- 0.42 mmol/l (p < 0.05), TG 1.94 +/- 0.30 mmol/l (p < 0.05), ApoB 1.43 +/- 0.04 g/l (p < 0.01), and LDL 3.75 +/- 0.34 mmol/l (p > 0.05). Before therapy, TNF-alpha levels in atherosclerotic patients were higher than in control subjects, 19.2 +/- 1.6 and 9.9 +/- 1.1 pg/ml, respectively (p < 0.01). After 1-month therapy, TNF-alpha levels in atherosclerotic patients were 9.2 +/- 1.0 pg/ml (p < 0.01). Similarly, the initial levels of IFN-gamma were higher in atherosclerotic patients compared with healthy subjects, 44.4 +/- 5.3, and 19.4 +/- 2.1 pg/ml, respectively (p < 0.01). After fenofibrate therapy, IFN-gamma levels decreased to 24.8 +/- 2.9 pg/ml (p < 0.01). The decreased levels of TC, TG, and LDL correlated with the decreased levels of TNF-alpha and IFN-gamma. CONCLUSION: The results of this study indicate that plasma TNF-alpha and IFN-gamma levels in hyperlipidemic patients are higher than in healthy subjects, and that fenofibrate is effective in decreasing lipids and cytokines in plasma.

Adult↗
PubMed1998

Influence of neuroleptics on cytotoxic activity of macrophages in rats.

The aim of the study was to evaluate the influence of neuroleptics on the in vivo and in vitro activities of rat spleen macrophages. In the in vivo study, three neuroleptics (chlorpromazine, haloperidol, and sulpiride) were given once, for 14 or 28 days. In the in vitro study, we evaluated the effects of two different concentrations of the neuroleptics on 3-day cultures of spleen macrophages. Rat spleen macrophages were isolated by the adherence method, and their cytotoxic activity was determined by measuring 51 Cr release from target cells P-815. In the in vitro study, both concentrations of all neuroleptics did not alter the cytotoxic activity of macrophages. In the in vivo study, neuroleptics (chlorpromazine 2 mg/kg, haloperidol 0.5 mg/kg, sulpiride 50 mg/kg) enhanced the cytotoxicity of macrophages both after a single injection and after 14 days. The results of the study indicate that the immunomodulatory effects of the neuroleptics depend mainly on dosage and experimental conditions.

Animals↗
PubMed1998

[The values of selected lipid parameters and atrial pressure in persons with hyperinsulinemia and normal glucose tolerance].

In 60 healthy non-obese persons we determined fasting plasma insulin concentrations. Afterwards we performed test with oral load with 75 g glucose. We determined plasma concentration of insulin one hour and two hours after this load; we found that 14 of 60 subjects had hyperinsulinemia with normal glucose tolerance. In the group of persons with hyperinsulinaemia we have shown the increase of fasting plasma triglyceride levels and elevated diastolic blood pressure. We suggested that healthy persons with hyperinsulinemia and normal glucose tolerance have an increase risk for cardiovascular diseases.

Cardiovascular Diseases↗
PubMed1998

Influence endothelin ETA receptor antagonist--BQ-123--on changes of endothelin-1 level in plasma of rats with acute vasospasm following subarachnoid hemorrhage.

Endothelin participates in regulating the vascular tone, and it is also involved in the pathogenesis of vasospasm following subarachnoid hemorrhage (SAH). Endothelin-1 (ET-1) induced cerebral vasospasm is inhibited by ETA receptors specific antagonist-BQ-123; this protects the neurons from ischemic damage. The present study evaluates the dynamics of ET-1 concentration changes in the plasma of rats in the acute phase of vasospasm after SAH, which was induced by administering 100 microliters non-heparinized fresh autologous arterial blood into the brain cisterna magna (CM). The study also assesses the effect of blocking ETA receptors on the changes in ET-1 level. BQ-123, the specific ETA receptors antagonist, was administered to cerebrospinal fluid (CSF) through a cannula inserted into CM; the antagonist--40 nmol in 50 microliters CSF--was given 20 minutes prior to SAH. In the control group, sham SAH was induced by administering 100 microliters artificial CSF (aCSF) to CM. ET-1 concentration in the plasma of rats in the acute phase of vasospasm was assessed by radioimmunoassay 30 and 60 minutes after SAH or sham SAH. It has been showed that both SAH and sham SAH cause significant increase in the ET-1 concentration (p < 0.05) in the rat plasma after 30 minutes; the concentration returns to an initial value after following 30 minutes, which may suggest that ET-1 released binds to its receptors in the acute phase of the vasospasm. On the other hand, in the two groups of rats with blocked ETA receptors there was a significant rise in ET-1 concentration 30 minutes after SAH or sham SAH, and a still further rise was observed 60 minutes after the procedure. The rise was significantly higher in animals with SAH (p < 0.05). The dynamics of the ET-1 concentration changes observed in rats with blocked ETA receptor suggests that SAH is an ET-1 production stimulator significantly more potent than other factors assessed in the study, such as a rise in the intracranial pressure resulting from administering aCSF to CM. Blocking ETA receptors makes it impossible for the ET-1 released to bind to the receptors, which may be a factor preventing the occurrence of cerebral vasospasm following SAH.

Animals↗
PubMed1998

Evaluation of plasma cyclic GMP assay as a screening test for detection of acute cardiac allograft rejection.

Our aim was to assess the value of a single determination of plasma cyclic guanosine 3',5'-monophosphate (cGMP) in noninvasive screening for acute cardiac allograft rejection warranting augmentation of immunosuppression. Plasma cGMP levels were measured in 26 patients 1 to 13 months after heart transplantation on the same day the endomyocardial biopsies were performed. Acute moderate rejection (ISHLT 3A or 3B) was found in 10 out of 17 subjects (59%) with plasma cGMP >5 nmol/L, whereas there was mild or no rejection (ISHLT 0 to 1) in 8 from among 9 subjects (89%) with cGMP <5 nmol/L. Because cGMP levels <5 nmol/L appear to argue against the presence of acute rejection requiring therapy modification, our preliminary results suggest that a single plasma cGMP assay might be helpful in establishing indications for endomyocardial biopsy in heart transplant recipients.

Acute Disease↗
PubMed1997

Neuropeptide Y-like immunoreactivity in lumbar cerebrospinal fluid of patients after severe head trauma.

We studied head-injured patients assessed after admission to the hospital according to the Glasgow coma scale (3-8 points). All of them underwent surgical procedure after neuroradiological examination. Due to therapeutic problems, some of these patients had lumbar puncture on the fourth day following surgery. The control group consisted of patients with lumbosacral discopathy in whom lumbar puncture was performed during radiculography. The level of neuropeptide Y (NPY) was examined in 5 ml of cerebrospinal fluid (CSF). The concentration of NPY in CSF was assayed radioimmunologically. Taking into account our results and the clinical course of disease we suggest that high concentration of NPY in lumbar fluid in severe head-injured patients may contribute to poor clinical outcome.

Adult↗
PubMed1997

Concentration of enkephalins in cerebrospinal fluid of patients after severe head injury.

We studied head-injured patients treated at the Department of Neurosurgery, Silesian University School of Medicine, Katowice. The patients underwent lumbar puncture on days 1, 4 and 7 for diagnostic reasons. The levels of leu-enkephalin (LENK) and met-enkephalin (MENK) were examined in 4.5 ml of cerebrospinal fluid (CSF). The control group included patients with lumbar discopathy from whom CSF fluid was collected during myelography. Enkephalins were extracted by column chromatography and their levels were assayed radioimmunologically. The results indicate that enkephalins may play a certain role in the pathophysiological response of nervous tissue to traumatic injury. Constantly elevated MENK levels together with decreasing LENK levels in patients with a Glasgow coma scale score < or = 8 may be useful as a poor prognostic factor. It is also suggested that LENK and MENK play different pathophysiological roles.

Adult↗
PubMed1997

Clonidine administration increases neuropeptide Y immunoreactivity and neuropeptide Y mRNA in the rat cerebral cortex neurons.

The effect of alpha 2 adrenoceptor stimulation on neuropeptide Y (NPY) and NPYmRNA expression was studied in the rat cerebral cortex. For receptor stimulation clonidine was used in a dose of 50 micrograms/kg s.c., 3 times at every 8 h; brains were studied 30-40 min after the last dose using radioimmunoassay (RIA), immunocytochemistry and in situ hybridization methods. The RIA of NPY did not show any significant changes in the NPY immunoreactivity (IR) level in the whole cortex, whereas the immunohistochemical analysis demonstrated an increase in the number of NPY-IR neurons in ventral cortical regions, especially in external cortical layers. In situ hybridization histochemistry of NPYmRNA also performed in ventral cortical sections showed that clonidine increased NPY synthesis in some cortical neurons. The obtained results indicate that the alpha 2 adrenoceptor stimulation by clonidine increases the NPY content and synthesis in rat cortical neurons.

Adrenergic alpha-Agonists↗
PubMed1997

[The analysis of rationale in antibiotic usage in certain maternity and gynecological wards and analogous outpatient clinics].

The aim of this work was the analysis of the correctness of therapeutic and preventive use of chemotherapeutic agents by the gynaecologists in their hospital and outpatient treatment. 1774 orders concerning chemotherapy or antibacterial chemoprophylaxis in 4 chosen health institutions (2 maternity-gynaecological wards and 2 analogous out-patient departments) were analysed. While evaluating each course indications for chemotherapy, choice of drug, each dose, way and time of administration were considered. In analysed health institutions 22.1-40.1% of used chemotherapeutics were applied without reasonable indications. In 11.3-27.7% of indicated cases the right chemotherapeutic was not chosen properly. Improper dosage concerned 0.0-23.7% of analysed courses of chemotherapy. It was no reservation for the ways of administration of the drugs. The inappropriate time of usage referred to 5.6-21.4% of analysed courses.

Ambulatory Care↗
PubMed1996

Neuropeptide Y (NPY) and its mRNA in discrete brain areas after subchronic administration of neuroleptics.

Classical (chlorpromazine, haloperidol) and atypical (sulpiride and clozapine) neuroleptics applied for a period of 2 weeks diminished neuropeptide Y (NPY) levels in nucleus accumbens, but not in striatum. These changes were correlated with NPY mRNA level. However, the effect of these neuroleptics on the level of NPY in hypothalamus was different. It is suggested that changes in NPY levels caused by neuroleptics are mediated by dopaminergic D1/D2 receptors.

Animals↗
PubMed1996

Atrial natriuretic peptide secretion following subarachnoid hemorrhage in spontaneously hypertensive rats.

Atrial natriuretic peptide (ANP) is released excessively in spontaneously hypertensive rats (SHR), and vasodepression is its main effect on the blood vessels. The aim of the study was to investigate the changes in ANP secretion in the cerebral vasospasm following subarachnoid hemorrhage (SAH) in SHRs. The SAH was induced by the injection of 100 microliters of unheparinized, autologous blood into the cerebrospinal fluid (CSF), via a canule formerly inserted into the cisterna magna (CM). In the sham SAH group the SAH was imitated with 0.9% saline injection. The concentrations of ANP in the blood samples obtained in the acute and chronic stages of vasospasm were radioimmunoassayed with commercial RIA kits (Peninsula RIK 9103). It was found that both SAH and sham SAH induced a significant increase in plasma ANP in the chronic phase of vasospasm. No such changes were observed in the acute phase. This shows that the chronic cerebral vasospasm following SAH considerably enhances the ANP secretion in SHRs, probably through the increased endothelin release. These compensatory and regulatory mechanisms help prevent the development of brain oedema and the progression of vasopasm through secondary vasodilation.

Animals↗
PubMed1995

Vitamin C and the common cold: a retrospective analysis of Chalmers' review.

In 1975 Thomas Chalmers analyzed the possible effect of vitamin C on the common cold by calculating the average difference in the duration of cold episodes in vitamin C and control groups in seven placebo-controlled studies. He found that episodes were 0.11 +/- 0.24 (SE) days shorter in the vitamin C groups and concluded that there was no valid evidence to indicate that vitamin C is beneficial in the treatment of the common cold. Chalmers' review has been extensively cited in scientific articles and monographs. However, other reviewers have concluded that vitamin C significantly alleviates the symptoms of the common cold. A careful analysis of Chalmers' review reveals serious shortcomings. For example, Chalmers did not consider the amount of vitamin C used in the studies and included in his meta-analysis was a study in which only 0.025-0.05 g/day of vitamin C was administered to the test subjects. For some studies Chalmers used values that are inconsistent with the original published results. Using data from the same studies, we calculated that vitamin C (1-6 g/day) decreased the duration of the cold episodes by 0.93 +/- 0.22 (SE) days; the relative decrease in the episode duration was 21%. The current notion that vitamin C has no effect on the common cold seems to be based in large part on a faulty review written two decades ago.

Ascorbic Acid↗
PubMed1995

Reactivity of isolated human right atria to norepinephrine in various disease states.

The reactivity of isolated, electrically driven, right human atrial muscle to norepinephrine was studied in patients with coronary heart disease, with and without proximal right coronary artery occlusion, and in patients with mitral valve disease. The dose-effect curves for norepinephrine and ED50 doses for each group were compared. We found no difference in reactivity of atria from both coronary artery disease groups. The mitral valve disease group dose-effect curve was shifted to the right (potency ratio 3.98), and the maximal effect was significantly higher than in both coronary artery disease groups. We suggest that adrenoreceptor down regulation could account for observed ED50 difference. The difference in maximal responses could depend on more effective contraction mechanism in mitral valve disease myocardium. We conclude that occlusion of proximal right coronary artery does not necessarily mean ischaemia of right atrium and/or ischaemia does not change myocardium reactivity to norepinephrine.

Atrial Function, Right↗
PubMed1995

Leucine enkephalin level in rat hypothalamus, striatum, hippocampus and adrenal glands in experimental rat uremia.

The aim of the study was to analyze the effect of experimental uremia elicited in Wistar rats by 5/6 kidney resection on the leu-enkephalin level in hypothalamus, striatum, hippocampus and adrenal glands. We found, that in uremic rats leu-enkephalin levels decreased in striatum and in adrenal glands. The level of leu-enkephalin in adrenal glands was directly related to plasma creatinine. The weight of uremic rats was significantly lower than that of control rats.

Adrenal Glands↗