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Biomedical subjects

H Gabriel

Publications and source records attributed to H Gabriel.

At least 37 records · Page 2Linked to original sources
PubMed1996

Effects of antihypertensive therapy on glucose and lipid metabolism.

Large epidemiological studies demonstrate only moderate reduction in the incidence of coronary artery disease by antihypertensive drug treatment. This is attributed to the prevalence of multiple risk factors in hypertensive patients and to possible adverse metabolic effects of antihypertensive drugs which may counteract their ability to reduce the risk of cardiovascular disease. The choices for pharmacological blood pressure reduction are divided between five classes with similar antihypertensive efficacy but markedly different influence on coronary risk factors. Hence, the clinician has to consider the prevalence of coexisting coronary risk factors, comorbidity as well as the efficacy, side effects, and mechanisms of drug action.

Antihypertensive Agents↗
PubMed1996

The ACE-inhibitor lisinopril affects plasma insulin levels but not fibrinolytic parameters.

There is evidence that ACE-inhibitors exert beneficial effects on endogenous fibrinolysis in patients with previous myocardial infarction. It is still unknown if this effect is restricted to this patient group only and by which mechanisms ACE-inhibitors exhibit the profibrinolytic effects. One possible explanation might be the positive influence of ACE-inhibitors on insulin metabolism by decreasing plasma insulin which in turn could decrease PAI-1, a major regulator of the fibrinolytic system. Therefore the present study examines the relationship between insulin and PAI-1 plasma levels during intravenous glucose tolerance tests before and after administration with the ACE-inhibitor lisinopril in 12 male obese patients with angiographically proven coronary artery disease and borderline hypertension. After a 4-weeks wash-out period glucose tolerance tests were performed before and after lisinopril-treatment (10mgs/d) for 12 weeks. After the treatment period, fasting plasma insulin level decreased from 15.6 +/- 2.1 to 11 +/- 1.8 uU/ml, p < or = 0.01. Stimulated levels of insulin during glucose tolerance test also significantly decreased by lisinopril (peak insulin from 57 +/- 10 to 41.2 +/- 7.3 uU/ml, p < or = 0.02). Basal plasma tissue plasminogen activator antigen, PAI-1 total antigen and PAI-1 "active" antigen were unaffected by therapy (8.4 +/- 0.5 vs 8.6 +/- 0.5 ng/ml, 118 +/- 20 vs 124 +/- 16 ng/ml and 21 +/- 7 vs 30 +/- 7 ng/ml, respectively). Our data confirm a beneficial effect of lisinopril on plasma levels of insulin but failed to demonstrate any profibrinolytic effect in this study population, thus questioning the postulated mechanism of influencing endogenous fibrinolysis by changes of plasma insulin.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1996

Ultrasound of the abdomen in endurance athletes.

This project evaluated, if athletes show adaption of their abdominal organs in response to endurance training. Abdominal sonography was performed in 26 sedentary male subjects [CO; age: 26 (SD 5) years; mass (BM): 78.7 (SD 10.6) kg; lean body mass [LBM): 67.1 (SD 7.4) kg; height (HE): 183 (SD 6) cm, individual anaerobic threshold (cycle ergometry; IAT): 2.1 (SD 0.1) W*kg(-1)], 14 moderately endurance trained athletes [EA1; age: 27 (SD 4) years; BM: 74.0 (SD 5.9) kg; LBM: 64.6 (SD 4.5) kg; HE: 178 (SD 5) cm, IAT: 3.0 (SD 0.5) W*kg(-1)] and 27 well endurance trained athletes [EA2; age: 27 (SD 4) years; BM: 72.1 (SD 4.3) kg; LBM: 65.4 (SD 3.2) kg; HE: 179 (SD 4) cm, IAT: 3.7 (SD 0.4) W*kg(-1)]. One subject of EA2 had cholecystolithiasis and another one renal redoublication. 3 persons showed uncomplicated parapelvine or subcapsular renal cysts (CO, EA1). The transverse area of the large abdominal arteries (abdominal aorta, common iliac arteries) was significantly greater in EA2 than in both EA1 and CO and partly greater in EA1 than in CO. Also, the ratios of sagittal and transverse diameters of the left and right lobes of the liver to LBM showed higher values for EA2 than for both EA1 and CO. These results indicate morphological adaptive processes of the great abdominal arteries in endurance athletes.

Abdomen↗
PubMed1996

Effects of intraaortic balloon pumping on coronary and carotid flow during percutaneous cardiopulmonary support.

Previous studies have suggested an improved clinical outcome when percutaneous cardiopulmonary support is combined with intraaortic balloon counterpulsation in patients with cardiogenic shock. We evaluated the effect of combined intraaortic balloon counterpulsation and percutaneous cardiopulmonary support therapy on coronary and cerebral blood flow by Doppler measurements in the coronary and the carotid arteries in a patient with cardiac arrest. During pacemaker stimulation, intraaortic balloon counterpulsation in addition to percutaneous cardiopulmonary support markedly improved coronary and carotid blood flow. Possible mechanisms are discussed.

Cardiac Pacing, Artificial↗
PubMed1996

Three-dimensional echocardiography using a transoesophageal imaging probe. Potentials and technical considerations.

Appreciation of three-dimensional relationships could be useful in cardiac diagnosis, decision making and planning of surgery. However, current ultrasound techniques provide only two-dimensional views. A recently developed echocardiographic computerized tomography unit allows reconstruction of three-dimensional images from a series of transoesophageal slices. To evaluate the potentials and limitations of this technique we performed echo computer tomographic examinations in 104 patients with a total number of 227 scans. All but two patients tolerated the procedure well and no serious complications were encountered. Indications for echo computer tomography included coronary artery disease, valvular heart disease, atrial masses, myocardial infarction, mitral and aortic valve replacement, aortic aneurysm and congenital defects. Most of the anatomical structures could be visualized with the best results obtained for the left atrium, the left ventricular outflow tract and the aortic and mitral valve apparatus. However, a variety of technical factors must be considered to achieve optimal results and to avoid misinterpretation. In 86% of patients the underlying pathology could be visualised by echo-computed tomography, particularly congenital defects such as those of the atrial or ventricular septa, but mitral valve pathologies provided the best results. In these cases three-dimensional imaging led to a better perception and understanding of structural relationships. In conclusion, despite current limitations in data acquisition, processing and computing power, echo computer tomography has the potential to provide relevant information in selected clinical settings.

Aortic Valve↗
PubMed1996

Middle cerebral artery velocity correlates with nitroglycerin-induced headache onset.

Headache often accompanies treatment with nitroglycerin, but the cerebral hemodynamic effects and the exact mechanism of the headache are incompletely understood. Transcranial Doppler monitoring allows evaluation and monitoring of changes in blood flow velocity in the large intracranial arteries. The objective of this study was to assess middle cerebral artery (MCA) blood flow velocities with transcranial Doppler monitoring in subjects receiving continuous low-dose nitroglycerin intravenously or by patch, and correlate these with clinical headache. Twenty-eight normal adult men received nitroglycerin (0.12 micrograms/kg/min intravenously [n = 14] or 0.6 mg/min by transdermal patch [n = 14]), for up to 120 minutes, with monitoring of clinical headache status (standard 4-point scale), blood pressure, heart rate, end-expiratory PCO2 (CO2), and right MCA velocity. All subjects developed headache (mean time to onset, 34 min), reaching moderate or severe levels in 20. There were no differences in age, weight, mean blood pressure, mean heart rate, or resting end-tidal CO2 between those whose headache reached a moderate to severe level and those whose headache remained mild. MCA velocity decreased from baseline values at all levels of clinical headache (onset, -17%; moderate, -18%; severe, -16%; nitroglycerin stopped, -19%) (p, 0.0001 by t test for each stage of headache). MCA velocity remained decreased at the time of headache resolution (-14%; p < 0.001). Blood pressure, heart rate, and CO2 did not change significantly. There were no differences related to route of nitroglycerin dosing. These data show that continuous low doses of nitroglycerin by patch or intravenously produce headache in normal male subjects. MCA velocities were significantly decreased at headache onset and at all levels of headache severity. Changes in MCA velocity persisted beyond the clinical headache. These results suggest a direct MCA vasodilatory effect of nitroglycerin. This method may also be used to evaluate the intracranial hemodynamic effects of other vasoactive drugs, even in clinical settings.

Administration, Cutaneous↗
PubMed1996

Peripheral blood mononuclear phagocyte subpopulations as cellular markers in hypercholesterolemia.

Mononuclear phagocytes play a major role in the development of vascular lesions in atherogenesis. The goal of our study was to characterize circulating blood monocyte subpopulations as potential cellular markers of systemic immunological abnormalities in hypercholesterolemia. In normal subjects, three-parameter immunophenotyping of whole blood revealed that 61.3 +/- 6.0% of monocytes showed "bright" expression of the lipopolysaccharide receptor (LPSR: CD14) and Fc gamma receptor I (RI: CD64) without expression of Fc gamma-RIII (CD16). Other monocyte subsets (populations 2, 3, 4, and 5) were characterized by the simultaneous expression of both Fc gamma-R's (25.6 +/- 5.0%), isolated expression of Fc gamma-RIII (9.4 +/- 1.7%), or high expression of CD33 (3.7 +/- 1.1%) with only dim expression of CD14, respectively. The smallest subset of monocytes (population 5: 2.1 +/- 0.8%) differed from the predominant population of CD14brightCD64+CD16- monocytes by additional expression of neural cell adhesion molecule (N-CAM: CD56). In a group of hypercholesterolemic patients (n = 19), high density lipoprotein cholesterol levels were negatively correlated to the population size of CD64-CD16+ monocytes. In both healthy subjects (n = 55) and hypercholesterolemic patients, the rare apolipoprotein E3/E4 and E4/E4 phenotypes were associated with a tendency toward a larger population of CD64-CD16+ monocytes. Expression of the variant activation antigen CD45RA by peripheral blood mononuclear phagocytes showed a positive correlation to plasma levels of the atherogenic lipoproteins low density lipoprotein and lipoprotein(a). These data suggest that systemic abnormalities in mononuclear phagocyte subpopulations may play a role in the pathogenesis of atherosclerosis.

Adult↗
PubMed1996

Regression of coronary atherosclerosis and amelioration of renal function during LDL-immunoadsorption therapy in a renal transplant recipient.

Hyperlipoproteinemia is frequently observed in patients after renal transplantation and contributes to cardiovascular morbidity and mortality. In addition, it was recently shown that hypercholesterolemia accelerates the progression of renal disease. In a renal transplant recipient (RTR) with severe coronary heart disease, familial hypercholesterolemia and decreased renal function, immunospecific LDL-apheresis was instituted since dietary restrictions failed to sufficiently improve hyperlipoproteinemia and medication had to be avoided due to drug interactions. Over a period of 36 months 145 LDL-apheresis treatments were performed at weekly intervals. The desorption of 5600 ml plasma volume allowed a mean reduction of total cholesterol by 56.6% (from 256 mg/dl to 110 mg/dl), of LDL-cholesterol by 63.0% (from 163 mg/dl to 58 mg/dl), of Lp(a) by 68.3% (from 34 mg/dl to 11 mg/dl) and of triglycerides by 49.6% (from 332 mg/dl to 163 mg/dl). Although temporarily decreasing during each apheresis session by 9.0%, HDL-cholesterol values increased during the first 9 months of treatment and remained within the normal range (> 45 mg/dl) thereafter. Cyclosporine A blood trough values were decreased by 32% during LDL-apheresis. Symptoms of angina pectoris rapidly improved and disappeared after 8 months of apheresis treatment. Initial coronary angiography exhibited serious three-vessel-disease, without the possibility of bypass grafting. Coronary angiography repeated after two years of therapy showed a regression of the disease. Serum creatinine levels declined during treatment (from 2.7 mg/dl to 1.8 mg/dl) and proteinuria did not increase further. This is the first report to show that long-term LDL-immunoadsorption is a safe and highly effective treatment of severe hyperlipidemia and coronary heart disease in a RTR, resulting in regression of vascular pathology. Moreover, amelioration of hyperlipidemia may have improved transplant function. Multicenter studies are necessary to confirm our results.

Adult↗
PubMed1995

Increased phagocytic capacity of the blood, but decreased phagocytic activity per individual circulating neutrophil after an ultradistance run.

The effect of a long strenuous endurance exercise on the phagocytic function of neutrophils was examined. 9 athletes [7 males, 2 females, age: 36-68 years, body mass: 64 (SD 10) kg, height: 175 (SD 10) cm] completed a competetive 100 km run in 8:07 (median value; range: 7:29-9:50 hours). In a whole blood assay the phagocytosis of opsonized E. coli, the receptor density of the Fc gamma receptor 3 (CD16) and the complement receptor 3 (CD11b, direct immunofluorescence) of neutrophils were measured on a per cell basis by flow cytometry before and up to 3 hours after the race. The phagocytic rate (percentage of neutrophils incorporating bacteria) was unchanged after exercise, whereas the phagocytic activity (number of incorporated bacteria per cell) was significantly reduced by -34 (SD 8) % (Wilcoxon test, P < 0.001). The total phagocytic capacity of the blood increased 2-3fold post exercise. The surface antigen expressions of CD11b and CD16 were unaffected by the ultradistance run. The results indicate either a reduced phagocytic function of neutrophils on a single cell basis or the mobilization of neutrophils of the marginal pool with a lower phagocytic activity. However, after a long endurance exercise the phagocytotic capacity of the blood was enhanced due to increased cell concentrations.

Adult↗
PubMed1995

Increase of serum insulin and stable c-peptide concentrations with exhaustive incremental graded exercise during acute hypoxia in sedentary subjects.

Hypoxia was shown to reduce insulin concentrations at rest and during exercise. However, some studies have also demonstrated increases in the hormone associated with arterial desaturation. This study was conducted in order to decide [1] whether acute alveolar hypoxia increased or decreased the circulating insulin levels, and [2] to elucidate whether interactions of insulin with other hormones were of relevance in this respect. Glucose (GLU), insulin (INS), c-peptide (CP), adrenaline and noradrenaline (CATs), atrial natriuretic peptide (ANP) and cortisol (CORT) as well as the capillary blood gases were determined in 15 healthy fasting male volunteers (age: 26.2 +/- 2.8 years, body mass index: 22.4 +/- 2.7 kg.m-2). On two separate test days the subjects breathed, in random order, either normal air (N) or a gas mixture with reduced oxygen content (H; FIO2: 0.14). Measurements were made at rest as well as during an incremental cycle exercise in a supine position (increments of 6 min and 50 W) at 100 W and 150 W, at volitional exhaustion (N: 227 +/- 36 W; H: 200 +/- 32 W) as well as in the 5th min of recovery. Arterial desaturation was seen throughout on H-day. At rest all hormones and GLU were normal and showed no influence of H. During exercise INS remained constant on N-day, increased on H-day and was significantly higher with H than with N, most pronounced at 150 W and at volitional exhaustion with 20%, respectively. For CP and GLU no significant exercise-induced changes were seen on either test day and no influence of H was detected.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1995

Blood hormones as markers of training stress and overtraining.

An imbalance between the overall strain experienced during exercise training and the athlete's tolerance of such effort may induce overreaching or overtraining syndrome. Overtraining syndrome is characterised by diminished sport-specific physical performance, accelerated fatiguability and subjective symptoms of stress. Overtraining is feared by athletes yet there is a lack of objective parameters suitable for its diagnosis and prevention. In addition to the determination of substrates (e.g. lactate, ammonia and urea) and enzymes (e.g. creatine kinase), the possibilities for monitoring of training by measuring hormonal levels in blood are currently being investigated. Endogenous hormones are essential for physiological reactions and adaptations during physical work and influence the recovery phase after exercise by modulating anabolic and catabolic processes. Testosterone and cortisol are playing a significant role in metabolism of protein as well as carbohydrate metabolism. Both are competitive agonists at the receptor level of muscular cells. The testosterone/cortisol ratio is used as an indication of the anabolic/catabolic balance. This ratio decreases in relation to the intensity and duration of physical exercise, as well as during periods of intense training or repetitive competition, and can be reversed by regenerative measures. Correlations have been noted with the training-induced changes of strength. However, it seems more likely that the testosterone/cortisol ratio indicates the actual physiological strain in training, rather than overtraining syndrome. The sympatho-adrenergic system might be involved in the pathogenesis of overtraining. Overtraining appears as a disturbed autonomic regulation, which in its parasympathicotonic form shows a diminished maximal secretion of catecholamines, combined with an impaired full mobilisation of anaerobic lactic reserves. This is supposed to lead to decreased maximal blood lactate levels and maximal performance. Free plasma adrenaline (epinephrine) and noradrenaline (norepinephrine) may provide additional information for the monitoring of endurance training. While prolonged aerobic exercise conducted at intensities below the individual anaerobic threshold lead to a moderate rise of sympathetic activity, workloads exceeding this threshold are characterised by a disproportionate increase in the levels of catecholamines. In addition, psychological stress during competitive events is characterised by a higher catecholamines to lactate ratio in comparison with training exercise sessions. Thus, the frequency of training sessions with higher anaerobic lactic demands or of competition, should be carefully limited in order to prevent overtraining syndrome. In the state of overtraining syndrome and overreaching, respectively, an intraindividually decreased maximum rise of pituitary hormones (corticotrophin, growth hormone), cortisol and insulin has been found after a standardised exhaustive exercise test performed with an intensity of 10% above the individual anaerobic threshold.(ABSTRACT TRUNCATED AT 400 WORDS)

Biomarkers↗
PubMed1994

Cardiocirculatory and metabolic strain during rowing ergometry in coronary patients.

To investigate the suitability of rowing for cardiac rehabilitation, the cardiocirculatory and metabolic reactions during rowing (RE) and cycle (CE) ergometry were compared. Ten male normotensive subjects of an outpatient heart group (age 56 +/- 7 years, maximum performance on CE 2.0 +/- 0.4 W.kg-1) carried out a stepwise increasing test on an isokinetic rowing ergometer and a CE (increasing by 25 W every 3 min). In a 1-min break after each step, heart rate and blood pressure, blood concentrations of lactate, and the free catecholamines adrenaline and noradrenaline were measured. Four patients showed signs of myocardial ischemia occurring almost one step earlier on RE than on CE. In RE, the endurance and maximum performance were about 20 W lower than on CE. At similar workloads, heart rate, blood pressure, and concentrations of lactate and catecholamines measured significantly higher on RE than on CE. At workloads above the individual anaerobic threshold, the increase in adrenaline and noradrenaline was significantly higher on RE than on CE. The results can be explained by the lower work efficiency, the higher isometric demands with increased cardiac pressure load, and the higher mental stress in RE. Rowing is only suitable in cardiac rehabilitation when well-defined prerequisites have been considered.

Analysis of Variance↗