Search PubMed⌕ Search

Biomedical subjects

L Röcker

Publications and source records attributed to L Röcker.

At least 55 records · Page 3Linked to original sources
PubMed1987

Effects of diltiazem alone and combined with mefruside on cardiovascular response at rest and during exercise, carbohydrate metabolism and serum lipoproteins in patients with systemic hypertension.

The antihypertensive effects of the calcium antagonist diltiazem, both alone and combined with the diuretic mefruside, were assessed over 14 months in 36 patients with essential hypertension. Patients received 180 or 270 mg/day; those with inadequate response were given 270 mg/day plus mefruside, 20 mg/day. Both monotherapy and combination therapy significantly reduced blood pressure (BP) at rest and during exercise. However, adding mefruside did not significantly decrease BP below that achieved with diltiazem alone. After 14 months of therapy, the percentage of responders (patients with at least 10% reduction in diastolic BP at rest) was 64% for all patients, 100% (by definition) for those receiving diltiazem alone and 47% for those receiving the combination. Diltiazem decreased heart rate by 6% (4 beats/min at rest) (p less than 0.05). Combined therapy with mefruside did not further reduce heart rate. There were few adverse effects and no undesirable metabolic effects with either monotherapy or combined therapy. Plasma renin activity, aldosterone levels, carbohydrate metabolism, serum lipoprotein levels and routine laboratory test results were unchanged in both groups at the end of the study. Thus, diltiazem is an effective antihypertensive agent and apparently the combination of diltiazem and mefruside does not potentiate the antihypertensive effect of diltiazem alone during long-term therapy.

Adult↗
PubMed1987

[The hemostatic and fibrinolytic system in normal subjects and myocardial infarct patients. Effect of a standardized aerobic and anaerobic ergometric stress test].

After clinical examination, 14 asymptomatic post-infarction male patients and 12 healthy control persons, aged 35-62 years, underwent two bicycle-ergometry tests. After a 20-min aerobic test of moderate intensity both groups had slight activation of the clotting system simultaneously with favorably increased fibrinolytic activity. After stepwise submaximal aerobic exercise, postinfarction patients had marked activation of the thrombocytic system; beta-thromboglobulin rose significantly from 36 to 102 ng/ml. But compared to the results in healthy persons, fibrinolytic activity was significantly reduced in the postinfarction patients (euglobulin lysis time 135 and 100 min, respectively). In three patients with unfavorable reactions of the hemostasis and fibrinolysis systems, ischemic changes or multifocal ventricular extrasystoles were recorded in the ECG after the second exercise test. These results indicate that intensive physical exercise in postinfarction patients can change the dynamic equilibrium between hemostasis and fibrinolysis in the direction of an increased clotting tendency. For this reason postinfarction patients and elderly untrained persons, especially those with an increased coronary risk factor, should avoid endurance training involving anaerobic exercise. On the other hand, moderate training at aerobic level favorably influences the hemostatic equilibrium in both healthy and postinfarction patients.

Adult↗
PubMed1987

Beta-adrenoceptor stimulating and blocking agents in essential hypertension: single and combined therapy with terbutaline and metoprolol.

Single and combined therapy with terbutaline (10 mg/day) and metoprolol (200 mg/day) was assessed over 8 weeks in a double-blind parallel study in a total of 36 patients with essential hypertension grade I-II according to WHO criteria at rest and during exercise. Blood pressure was comparably reduced with metoprolol and terbutaline (I) and metoprolol alone (II) at rest as well as during exercise. Under terbutaline (III), only diastolic blood pressure decreased during exercise. The responder rates (greater than or equal to 10% reduction in diastolic blood pressure) at rest were 58% in I, 63% in II and significantly lower in III at 42%. Heart rate was not affected in I and III but decreased significantly with metoprolol. While therapy with metoprolol resulted in an increase of noradrenaline and a fall of plasma renin activity after 8 weeks, these parameters remained unchanged in I and III. Therapy was well tolerated in all groups. Terbutaline in the chosen dosage slightly decreased diastolic blood pressure and did not increase heart rate. Metoprolol is an effective antihypertensive agent resulting in a heart rate decrease. Under combined therapy, there is no additional blood pressure decrease, but the heart rate remains unaffected.

Adult↗
PubMed1986

Effect of chronic beta-adrenergic blockade on exercise-induced leukocytosis.

Chronic beta-receptor blockade on exercise-induced leukocytosis was studied in 11 hypertensive males. Blood samples for determinating leukocytes were taken before and during the 6th min and the 30th min of submaximal exercise, at maximal exercise, and 5 and 15 min after work. Lymphocytosis and granulocytosis were found to be dependent on the intensity and duration of the exercise. Leukocytosis during short-term and long-term exercise was due to both a lymphocytosis and granulocytosis. Under resting conditions, the chronic beta-receptor blockade caused a significant decrease of neutrophil granulocytes. Both the patients and the controls showed the same percent increase in leukocytes compared with the untreated control study. This suggests that the adrenergic system does not play the primary role in exercise-induced leukocytosis.

Acebutolol↗
PubMed1986

Blood platelet activation and increase in thrombin activity following a marathon race.

To see whether strenuous prolonged exertion increases blood platelet activation and thrombin activity in healthy well-trained men, 16 male amateur runners (mean age 31,8) were studied. A marathon race (mean time 2 h 44 min 30 s) caused a significant increase in plasma beta-thromboglobulin (beta-TG), platelet factor 4 (PF4), fibrinopetide A (FPA) and factor VIII (F VIII) activity. Sixty min after exertion beta-TG and F VIII activity were still significantly elevated. FPA continued to rise, reaching peak values 60 min after the run. 22 h after finishing the race F VIII activity was still significantly elevated. The study has demonstrated the great inter-individual variability of marathon race-induced haemostatic changes. The elevation of beta-TG varied from 42% to 156%, F VIII from 112% to 625%, and in three runners FPA reached more than 900% of its pre-exercise value. In some individuals the haemostatic changes observed could be potentially unfavourable for coronary heart disease prevention.

Adolescent↗
PubMed1985

Effects of dehydration on the vasopressin response to immersion.

Nine healthy volunteers underwent three experimental procedures in random order. The protocols were 4 h of thermal dehydration followed by 2 h of head-out water immersion, 4 h of thermal dehydration followed by 2 h of chair rest, and 6 h of rest in the supine position. Four hours of heat exposure (50 degrees C) resulted in a body weight loss of approximately 3.5%. Plasma osmolality rose by approximately 5 mosmol/kg, mean arterial pressure (MAP) decreased from 85 to 78 mmHg, and body temperature increased from 36.8 to 38.6 degrees C. As a consequence of the combined action of hypertonicity, hypovolemia, hypotension, and hyperthermia, plasma arginine vasopressin (AVP) increased from 2.1 to 8.1 pg/ml after 4 h thermal dehydration. Changes in body weight, plasma osmolality, body temperature, and MAP were similar after either a subsequent 2 h of water immersion or 2 h of chair rest. However, during chair rest plasma AVP remained elevated (8.4 pg/ml), whereas during immersion plasma AVP decreased from 8.1 to 4.7 pg/ml. This was probably due to the central hypervolemia induced by immersion. Our results support the hypothesis that central hypervolemia rather than hypotonicity is the primary stimulus for AVP suppression during water immersion in dehydrated subjects. During the early immersion period hypoosmolality might contribute to the AVP suppression.

Adult↗
PubMed1984

Venous pressure in man during weightlessness.

To determine whether the body fluid shift from the lower limbs toward the head that occurs during spaceflight leads to lasting increases of venous pressure in the upper body, venous pressure and hematocrit measurements were made on four astronauts before flight and 1 and 12 hours after recovery and compared with measurements in space. During the mission the hematocrit was elevated and the venous pressure lowered by 1 to 8 centimeters of water as compared with the preflight data. One hour after landing the hematocrit decreased, indicating a hemodilution, venous pressures were unexpectedly high, and a body weight loss of 4 to 5 percent was observed. Twelve hours later the venous pressures were the lowest recorded during the study. The fluid shift apparently takes place during the first several hours of spaceflight. Thereafter, the pressure in the peripheral veins and the central circulation is lower than that measured before flight.

Body Fluids↗
PubMed1982

Long-term observations on plasma antidiuretic hormone levels during and after heat stress.

Eleven healthy subjects aged 18--26 years underwent intermittent heat stress in a sauna bath. Blood samples were taken immediately before, during and at various intervals after heat exposure for the measurement of antidiuretic hormone, osmolality and percentage change of plasma volume. Antidiuretic hormone was increased during, immediately after and 90 min after heat stress. Three hours after the heat stress period antidiuretic hormone returned to control values in spite of a significant increase in osmolality and a significant decrease in plasma volume. These results imply that other factors than ADH are responsible for the long-term homeostasis of water balance and plasma volume.

Adolescent↗
PubMed1980

[Seasonal variation of blood components important for diagnosis (author's transl)].

In a comparative study, the differences between the values measured for 26 blood and serum components in both winter and summer were determined in 78 healthy subjects. Comparable conditions during the preparation of test persons, sampling, processing of specimens, and measurement were strictly observed. The term "season" is defined more precisely by meterological data. In the summer season, significantly higher values were found for leukocytes (9%), lactate dehydrogenase and MCHC (7% each), creatinine (7%, in women only), and MCH (1%) whereas significantly lower values were exhibited by aspartate aminotransferase (18%), alanine aminotransferase (14%), alkaline phosphatase (11%), glucose and packed cell volume (7% each), MCV (6%), total protein (2%), erythrocytes, albumin, sodium and chloride (1% each). These partly considerable alterations should be taken into account in the establishment of reference values and evaluation of laboratory findings (above all, when intraindividual comparison is involved). There were no significant alterations of the following parameters: hemoglobin, gamma-glutamyl transferase, urea, uric acid, creatinine (men only), bilirubin, cholesterol, total glycerol, potassium, calcium, and inorganic phosphate. In another series of experiments involving 32 test persons, the influence of different ambient temperatures during blood sampling on the above mentioned blood components was studied. Within the 18-30 degrees C range, no significant alterations were detected.

Blood Cell Count↗
PubMed1978

[Standardisation of obtaining blood samples: influence of tourniquet application on 33 constituents of blood and serum (author's transl)].

The extent and dynamics of changes by short (1 min) or prolonged (6 min) tourniquet application while obtaining venous blood samples were analysed with respect ot 33 frequently measured constituents of blood and serum. After 6-minute tourniquet application the values for red cells, haemoglobin, packed cell volume, total protein, albumen, gamma-glutamyl transferase, alkaline phosphatase, lactate dehydrogenase, creatinekinase, bilirubin, cholesterol, total glycerol and calcium increased by an average of 4-9%. One-minute tourniquet application did not have a significant effect. Levels of sodium, potassium, carbon dioxide, creatinine, uric acid, ratio of electrophoretic fractions and the MCV, MCH and MCHC indices were not affected even by 6-minute tourniquet applications. The introduction of blood sampling under standardised conditions is proposed.

Adult↗
PubMed1978

Sex-dependent changes in plasma globulins in women and men exposed to heat stress.

Healthy, sedentary women and men, aged 20 to 30 years, were exposed to the same degree of intermittent heat stress in a sauna bath. Blood samples were taken immediately before and at various intervals after heat exposure. The concentrations and intravascular masses of IgG, IgA, IgM, alpha1-antitrypsin, transferrin and alpha2-macroglobulin were determined by the radial immunodiffusion technique and by the measurement of plasma volume. Losses in body weight and plasma volume were lower in women than in men. The globulin concentrations increased significantly in both sexes after heat exposure. The sum of the masses of individual globulins increased only in women, a change interpreted as globulin shifts from the interstitial into the vascular space. Whereas it is unlikely that sex-dependent differences in these shifts are due to changes in vascular permeability, it seems that the protein composition of the lymphatic fluid entering the vascular space plays an important role in these shifts.

Adult↗
PubMed1977

Extracellular fluid volume and central circulation after long lasting exercise and dehydration in conscious dogs.

Two aspects of the recovery period after endurance exercise were investigated: a) the fluid distribution between the intra- and extravascular parts of the extracellular fluid volume (ECFV) induced by exercise dehydration, b) the cardiovascular response pattern [blood pressure (BP), heart rate (HR), cardiac output (CO), total peripheral resistance (TPR), and central venous pressure (CVP)] to the heat load which results from the preceding exercise. Seven conscious dogs performed endurance exercise in a cool environment (16 degrees C) on a horizontal treadmill till 4% of the body weight was lost. It was found that about 70% of the total fluid loss of the body came from intracellular water. During exercise sodium and chloride concentrations rose by 6 mMol and 7 mMol respectively (P less than 0.005) and remained elevated throughout the early recovery period indicating a fluid loss of about 100-200 ml out of the ECFV. Direct measurements of the ECFV as sulfate space confirmed these values. Since the plasma volume remained unchanged, this fluid loss was carried totally by the interstitial fluid volume. Immediately after exercise body temperature was elevated by 1.5 degrees C and returned towards control within 90 min. Cardiac output was above control level for 2 h after the end of exercise, at first due to an increased HR and thereafter to an elevated stroke volume (SV) (P less than 0.02). CVP and TPR were below control levels for at least 2 h (P less than 0.01). A linear correlation was found between CVP and TPR. A close correlation existed between the body temperature and the cardiovascular parameters. It can be concluded that even long after exercise the cardiovascular system has to serve thermoregulatory needs.

Animals↗
PubMed1977

The influence of heat stress on plasma volume and intravascular proteins in sedentary females.

23 untrained femal subjects underwent a standardised thermal dehydration. Plasma volume (PV), hematocrit (HCT), total intravascular protein concentration (TPC), albumin concentration (AC), total globulin concentration (TGC) were determined before, immediately, 90 min and 180 min after the heat stress. The intravascular protein masses (IPM) were calculated from PV and protein concentration. In comparison to men the loss of body weight and PV was smaller. Consequently the TPC does not increase to the same amount in men. A tendency for a diminution of IPM could be observed but this shift was not significant, compared to males. According to these findings the colloid osmotic capacity remained on a relatively high level. Opposite to men the IPM of globulins increased in females after thermal dehydration.

Blood Proteins↗
PubMed1977

Plasma volume and intravascular protein masses in trained boys and fit young men.

Plasma volumes and intravascular protein masses were measured in eight well-trained boys (VO2 max = 59.6 +/- 6.5 ml/kg body wt) aged 13-15 yr and compared with two groups of adult athletes aged 17-20 yr (VO2 max = 61.8 +/- 3.4 ml/kg body wt) and 24-30 yr (VO2 max = 63.3 +/- 4.1 ml/kg body wt), respectively. The trained boys had larger plasma volumes and increased intravascular masses of albumin and hepatogenic globulins as compared with values available for children with normal physical activity. There was no significant difference between the boys and the adults concerning maximal oxygen uptake, plasma volume, albumin, immunoglobins, and haptoglobin, when allowance was made for differences in body dimensions; probably due to the young age, however, the boys had considerably higher relative alpha2-macroglobulin and transferrin masses. Endurance training apparently elicits the same response of the plasma protein system regardless of age, at least after pubertal age has been attained. The overall effect of these changes implies an increase of the water binding capacity of the plasma

Adolescent↗