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Biomedical subjects

H Siewert

Publications and source records attributed to H Siewert.

At least 37 records · Page 2Linked to original sources
PubMed1987

[Kidney function in spontaneously hypertensive rats under minoxidil treatment].

In 25 spontaneously hypertensive rats the blood pressure was lowered from 192 +/- 11.6 to 130 +/- 11.7 mm Hg and in 26 normotensive Wistar rats from 129 +/- 9.1 to 107 +/- 6.7 mm Hg by applying 1 mg/kg body weight minoxidil twice a day orally. 19 spontaneously hypertensive and 21 normotensive rats served as untreated control groups. During the treatment the glomerular filtration rate, determined by the slope clearance of Tc-99m-DTPA, remained unchanged. Under maximal water diuresis the excretion fraction of sodium was diminished compared with the control data. The Na+ and water reabsorption was increased in the proximal tubules (not an aldosterone effect) only in the treated spontaneously hypertensive rats. The potassium clearance was increased in this group, but decreased in the treated normotensive group. The different reactions of the renal tubular function to the treatment with minoxidil in spontaneously hypertensive compared with normotensive rats were discussed in connection with changes of membrane transport in essential hypertension.

Animals↗
PubMed1986

[Differing acute effects of propranolol on the hypertensive heart during exercise].

Exercise investigations were performed in 39 male hypertensives (WHO stage I-III) to assess haemodynamics and cardiac function after intravenous application of 5 mg propranolol for the detection of latent heart failure. Radiocardiography was used to determine volumetric parameters such as LV end-diastolic volume and ejection fraction, and microcatheterization was employed to obtain the LV filling pressure via pressure measurement in the pulmonary artery (PA). The negative inotropic and chronotropic effects of propranolol on pump function and myocardial mechanics at rest were found to be minimal. During 50 watt exercise however, an increase of the diastolic PA pressure has been observed simultaneously with a diminution of cardiac output (stroke volume being constant). Thus, under acutely administered beta blockade, a general disturbance in the flow-pressure relation could be induced, being comparable to heart failure. Only in a few cases was the reduced contractility compensated by the Frank-Starling mechanism, but only if the mechanism did not participate in the regulation of pump function during the previous control investigation. In other cases a remarkable reduction of cardiac output and even stroke volume occurred, results which may be explained as a consequence of a reduced venous return (or pooling) connected with acutely induced vascular effects (beta-2 blockade).

Adult↗
PubMed1984

[Behavior of blood pressure and peripheral hemodynamics in interval therapy in untreated and propranolol-treated patients with arterial circulatory disorders of the lower extremities].

Searching for a possibility of an effective therapy of disturbances of peripheral arterial blood supply (stage I and II), the authors examined a medicamentously untreated group of patients as well as a comparable group of patients which was pretreated with propranolol. The two groups of patients performed twice a week an interval run exercise. Under the three-month training therapy in the two groups significant systolic and diastolic blood pressure reductions as well as statistically ascertained shortenings of the xenon-133-half-value time under working conditions and enlargements of the average functional vascular cross section A appeared. The distance of the intermittent claudication and the standardized moving up and down test prolonged. An influence on the microcirculation caused by propranolol could not be proved. The results are discussed on the basis of literature.

Adult↗
PubMed1983

[Effect of sauna and walking series on blood pressure, peripheral microcirculation and performance behavior in essential hypertension].

On the basis of two groups with hypertension (stage I and II) pre-treated with propranolol the authors report on possibilities of the assessment of therapeutic effects in physical therapy series. The systolic and diastolic behaviour of blood pressure at rest and under load as well as the peripheral blood supply before and after the therapeutic effect of sauna bath and running series lasting several weeks were investigated according to the principle of staying power. The xenon-133 muscle clearance served as method for the recognition of the peripheral microcirculation. In the series of sauna bath hyperthermia as well as in the running treatment significant reductions of blood pressure at rest and statistically provable improvements of the peripheral haemodynamics were the result. In higher degrees of load the hypertensive position of regulation is not influenced by the therapeutic method described.

Adult↗
PubMed1983

[Swim therapy in elderly patients with essential hypertension treated with beta receptor blockers].

It is reported on the behaviour of blood pressure and heart rate at rest as well as on the peripheral microcirculation of the working musculature after physical conditioning in older patients with essential arterial hypertension (stage I and II). The patients with hypertension conditioned in 4 groups (twice a week swimming or once a week swimming and run each with and without propranolol) showed systolic and diastolic decrease of blood pressure with the exception of some patients. The heart rate at rest was significantly reduced only in the groups with swimming twice a week with and without beta-blockers. By means of the xenon-133-half-life period with the exception of the run-swimming group in all groups could be proved significant improvements of the peripheral microcirculation after the therapy, in contrast to the time before therapy. Value and limits of the training treatment described for the influence on the factor of risk arterial hypertension at old age are discussed.

Aged↗
PubMed1983

[Experiences with the application of physiotherapy in peripheral arterial circulatory disorders of the lower extremities (stage I and IIa) under ambulatory conditions].

In a comparative study the authors report on results of series of physical therapy in disturbances of the peripheral arterial blood supply. Examined were the behaviour of blood pressure, the painless walking distance and the peripheral microcirculation with the xenon-133-muscle clearance method before and after treatments lasting 10 to 12 weeks with combined exercises consisting of gymnastics and walking according to the interval principle (twice a week), with sauna visits twice a week as well as before and after diadynamic series of the current. In all therapy groups an improvement of the peripheral haemodynamics could be statistically ascertained. The distance of the intermittent claudication prolonged particularly in the group with interval walking. In the walking group and in the sauna group the values of the systolic blood pressure were significantly reduced. Side-effects were not observed. Therapy effects of the series of physical therapy described are best to be proved by the xenon-133 muscle clearance.

Adult↗
PubMed1983

[Studies on central and peripheral hemodynamics using radiocardiography and Xenon-133 muscle clearance in patients with essential hypertension].

Examination of 80 patients with essential hypertension revealed a significant correlation between the tonus of peripheral muscular arterioles on the one hand, and the stage and duration of hypertension and age of the patients, on the other hand. The correlation between arteriolar tonus and indicators of cardiac pump function was less marked. The results confirmed the close relationship between changes of peripheral blood bed and development of hypertension. The use of 133Xe half-period for measuring the peripheral arteriolar tonus proved a simple, but informative method adding an important indicator of peripheral haemodynamics to the results of haemodynamic examination.

Adolescent↗
PubMed1983

[Unilateral catheterless determination of kidney function in hydronephrosis].

Whereas the value of quantitative separate determination of kidney functioning is undisputed for most urological and nephrological problems, its value for the judgement of hydronephrotic kidneys is doubted by various working groups. Using 15 mongrel dogs, the nuclide excretion at certain times, various calculation intervals and the results of separate functional analysis of hydronephrotic and non-hydronephrotic kidneys were compared. Due to the early nuclide excretion with an advanced secretion peak it is no longer acceptable to use a 2-minute calculation interval for hydronephrotic kidneys in dogs. If the upper limit of the calculation interval is prior to the secretion peak, there will be no overestimation of the hydronephrotic kidneys.

Animals↗
PubMed1982

[The behavior of blood pressure and peripheral hemodynamics in regular exercise therapy in patients with essential hypertension (stages I and II) of various age groups].

The authors report on the effect of a combined training programme decreasing blood pressure in male patients with essential hypertension (stage I and II) treated formerly not effectively with propranolol. Basis of the exercise treatment was the frequency of training which was established from the individual loading tests before the series of therapy. In three collectives of patients with hypertension of different age decreases of systolic as well as diastolic blood pressure could be ascertained statistically. With the help of the xenon-133 muscle clearance in most cases an improvement of the peripheral microcirculation could be proved. The mean functional vascular cross section (A) significantly increased under the training therapy.

Adult↗
PubMed1981

[On the significance of combined kinesitherapy for the rehabilitation of ageing people with essential hypertension (author's transl)].

Proceeding from their investigations the authors have formulated the following questions: 1. How do ageing people with essential hypertension tolerate sauna treatment (hyperthermia)? 2. What is the optimum thermal load for effective antihypertensive treatment? 3. What is the optimum interval, i.e. how many sauna baths are recommended per week? 4. Does an anti-hypertensive combination therapy consisting of sauna baths and jogging produce the same or even better results in aged hypertensives than sauna treatment on its own?

Age Factors↗
PubMed1980

[The heart in hypertension].

After indications to the great epidemiologic importance of hypertensive heart disease and its relationship with the ischaemic heart disease several results are reported collected during the past 10 years by examinations of more than 500 patients for early diagnosis of cardiac insufficiency in hypertension. The methods of microcatheterization of the pulmonary artery and radiography have been used (even under ergometrical exercise) as well as the calibrated apex cardiography and the echocardiography. For the practising physician a classification of hypertensive heart disease with 4 phases or forms is proposed. The paper ends with a demonstration of the close relationship between prevention and treatment of hypertension as well as between hypertensive and ischaemic heart disease at the same time in a sense of the integrative role of heart insufficiency.

Cardiomegaly↗
PubMed1979

[Treatment of experimental immune complex nephritis with indomethacin].

Functional, histological and immune-histological examination were performed in altogether 64 Wistar-rats, in order to control the effect of a therapy with 2 mg/kg per body weight indomethazine lasting 2 months at the model of an experimental immune complex nephritis. In 44 rats after presensibilisation an immune complex nephritis was performed by intraperitoneal injections with human serum albumin which were repeated three times a week. 24 glomerulonephritis animals and other 20 animals without glomerulonephritis were daily administered indomethazin through a tube probe, the remaining 20 animals with glomerulonephritis served as untreated control groups. The excretion function of the kidney was tested before the beginning of the experiment, 2 weeks after the beginning of the therapy and the regular serum injections, respectively, and before the end of the experiment by determination of the biological half-life period of 131J-hippuran. In every case one day before this the proteinuria during 24 hours was determined. At the end of the experiment the kidneys were examined histologically and immune-histologically. The results showed that indomethazin does not lead to a clear influence on the proteinuria in the immune complex nephritis of the rat. The excretion of 131J-hippuran was significantly restricted, whereas the histological and immune-histological preparations in the animals with foreign serum injections showed clear changes of the glomeruli in the sense of an early stage of the immune complex nephritis, however, they did not show any essential influence by indomethazin. That is, indomethazin had altogether no favourable effect on the immune complex nephritis of the rat.

Animals↗
PubMed1979

[A-wave in calibrated apex cardiogram in hypertension. Studies during rest and after exertion].

Apexcardiographic examinations were carried out of 86 hypertensive patients without clinically manifest heart failure. The amplitude of the wave a (or the per cent fraction of the wave a of the total amplitude) and the maximal rate of wave rise, df/dta were statistically significantly higher in the hypertensive patients than in normal subjects. The findings are interpreted as a manifestation of an increased left ventricular rigidity and of an increased atrial contractility in hypertensive patients. No correlation was found between the apexcardiographic indicators checked and the indicators of the cardiac pump function. In 46 hypertensive patients, in addition, a dynamic exercise test was performed (50 W for 6 min); 1 minute after cessation of exercise an apexcardiogram was recorded. An increase in the a/T quotient (greater than or equal to 5%) was found in 20; a decrease (=5%), in 10; and no change (less than +/- 5%), in 16 hypertensive patients. The postexercise apexcardiographic changes had no correlations with haemodynamic changes occurring during exercise.

Adolescent↗