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Biomedical subjects

H R Brunner

Publications and source records attributed to H R Brunner.

At least 217 records · Page 12Linked to original sources
PubMed1991

Antihypertensive therapy and mobilization of renal functional reserve.

The normal kidney can increase its rate of glomerular filtration in response to an acute protein load. It has been suggested that this acute hyperfiltration represents a renal functional reserve (RFR). The RFR has also been proposed to reflect the chronic hyperfiltration found in diabetic patients and animal models of chronic renal failure. The physiologic role of the RFR is still unclear. On the one hand, the availability of an RFR may retard the progression towards end-stage renal failure. On the other hand, sustained hyperfiltration has been implicated as a potential deleterious factor in the progression of renal disease. Antihypertensive drugs used in the management of hypertensive patients with chronic renal disease modify both the systemic and the renal hemodynamics. Depending on their hemodynamic effects, they may thereby alter the ability to mobilize RFR. Today, it is still not clear whether an ideal compound should increase, decrease, or not affect RFR to preserve long-term renal function. Evaluation of the effects of various antihypertensive agents on RFR could become an important aspect of consideration in order to optimize both the control of blood pressure and the capacity of the therapy to prevent deterioration of renal function.

Adrenergic beta-Antagonists↗
PubMed1991

Ambulatory blood pressure monitoring in children, adolescents and elderly people.

Non-invasive ambulatory blood pressure monitoring is increasingly being used in the diagnosis and the treatment of adult hypertensive patients. In children, the most obvious clinical use for intermittent blood pressure recordings is in the evaluation of borderline hypertension and the assessment of the efficacy of antihypertensive therapy. Adolescents who are hypertensive in the presence of the doctor are more often normotensive outside the physician's office than adult and elderly patients. Many elderly patients with isolated systolic hypertension have normal ambulatory systolic readings. Elderly patients with high blood pressures only in the physician's presence generally do not show a fall in ambulatory blood pressures when antihypertensive therapy is initiated or intensified. Thus, ambulatory blood pressure monitoring may be useful in detecting truly hypertensive patients among children and adolescents and in elderly people. This technique should make it possible to better define the cardiovascular risk, to avoid overtreatment and to individualize antihypertensive therapy.

Adolescent↗
PubMed1991

Evaluation of antihypertensive therapy: discrepancies between office and ambulatory recorded blood pressure.

Non-invasive ambulatory blood pressure monitoring has proved to be very useful in investigating hypertensive patients. So far, almost everything known about this technique is based on studies performed in specialized centers. We summarize here the results of two trials in which private physicians used ambulatory blood pressure monitoring to assess the efficacy of antihypertensive drugs. The results found in this clinical setting were very similar to those observed previously in specialized clinics. In the individual patient, the level of ambulatory recorded pressure could not be predicted from blood pressure readings taken at the doctor's office. Furthermore, the blood pressure response to antihypertensive therapy was more reproducible when evaluated by ambulatory blood pressure monitoring than by the doctor. It appears, therefore, that non-invasive ambulatory blood pressure monitoring is also useful in everyday practice for the management of hypertensive patients.

Antihypertensive Agents↗
PubMed1991

[Non invasive measurement of arterial compliance].

Pulse pressure waves are damped by the elastic properties of the blood vessels. This damping capacity can be evaluated by measuring vascular compliance a parameter which expresses changes of volume with respect to changes of pressure. Arterial compliance varies continuously with respect to intravascular pressure. Our group has developed an ultrasonograph which functions in the A mode capable of measuring the diameter of peripheral arteries during the cardiac cycle. This system is coupled to a photoplethysmograph which records non-invasively and continuously finger blood pressure. This enables construction of pressure-diameter graphs and the determination of arterial compliance and distensibility at each pressure value.

Arteries↗
PubMed1990

The renin-angiotensin system in hypertension: an update.

Although renin and angiotensin are still a puzzle, we are learning where some of the pieces fit. Recent studies indicate that in addition to ameliorating hypertension, ACE inhibitor therapy can prolong life in patients with severe congestive failure. Development of renin inhibitors and angiotensin II receptor antagonists may provide greater therapeutic specificity.

Angiotensin II↗
PubMed1990

[Angiotensin-converting-enzyme inhibition in arterial hypertension].

Angiotensin converting enzyme (ACE) inhibitors were developed to prevent the generation of angiotensin II and thereby to reduce peripheral vasoconstriction. These drugs have already proven their efficacy in the management of essential hypertension as well as of various forms of secondary hypertension. When given alone or in combination with other antihypertensive agents, they allow to normalize blood pressure of almost all patients. These compounds have favorable effects on hemodynamics and regional blood flow distribution. They do not affect lipid metabolism and have usually no deleterious influence on the quality of life. In view of their efficacy and tolerability profile, ACE inhibitors are likely to become widely used as first choice antihypertensive agents.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1990

[Evaluation of tolerance, efficacy and safety of 3-year simvastatin use in the treatment of primary hypercholesterolemia].

Simvastatin (synvinolin MK-733) is a potent inhibitor of 3-HMG-CoA-reductase, the key enzyme for cholesterol biosynthesis. To investigate the efficiency and safety of this new drug on a long term basis, simvastatin was administered for 3 years to ten patients with type II hyperlipoproteinemia. Daily dosages were 20 or 40 mg. The drug therapy produced a significant reduction in serum levels of total cholesterol (19-34%), LDL-cholesterol (26-44%) and Apo B (19-33%). Triglycerides decreased moderately (2-23%) while HDL-cholesterol and Apo A1 changed only slightly (-3 to 6% and 5-13% respectively). Simvastatin was well tolerated. No consistent adverse clinical or biochemical effects were observed during the three-year therapy. The results indicate that simvastatin is a promising new therapy for high risk hypocholesterolemic patients.

Aged↗
PubMed1990

Influence of sodium balance on atrial natriuretic factor in rats with one-kidney, one-clip renal hypertension.

The influence of sodium intake on the gene expression and circulating levels of atrial natriuretic factor (ANF) was investigated in unanesthetized rats with one-kidney, one-clip renal hypertension. After clipping, the rats were maintained for 3 weeks either on a salt-deficient (n = 11) or a regular-sodium diet (n = 10). Animals which had received the regular-sodium diet exhibited significantly higher ANF mRNA levels in their right and left atria than salt-restricted animals, whereas there was no significant difference in plasma ANF levels.

Animals↗
PubMed1990

Noninvasive blood pressure monitoring at the finger for studying short lasting pressor responses in man.

The study of vasoactive agents in man often requires accurate measurement of short-lasting changes in blood pressure. Using a noninvasive photoplethysmographic device (Finapres), the authors investigated in normotensive subjects whether rapid increases in blood pressure can be assessed precisely by monitoring finger blood pressure continuously. Six volunteers were studied on two consecutive days. On the first day, increasing doses of angiotensin I were injected intravenously with the aim to find a test dose which raised systolic blood pressure by 25 to 40 mm Hg. After oral administration of a placebo, the same test dose was injected repeatedly over the next 24 hours. On the second day, the subjects took either 6.25 (n = 3) or 25 mg (n = 3) captopril PO and the serial administration of the test dose of angiotensin I was continued for the next 4 hours. After placebo intake there was a good reproducibility of the blood pressure response to angiotensin I with a coefficient of variation of 15 +/- 4.5% (Mean +/- SD, n = 6). Captopril caused a dose-dependent inhibition of the pressor effect of angiotensin I. These data indicate that noninvasive blood pressure monitoring at the finger represents a useful tool to study short-lasting blood pressure changes produced by vasoactive agents in man.

Adult↗
PubMed1990

Renal and hemodynamic effects of atrial natriuretic peptide in patients with cirrhosis.

The effects of anaritide, a 25-amino-acid synthetic analogue of ANP, were evaluated in 28 patients with cirrhosis complicated by ascites and/or edema. Each patient received two doses of the agent, as well as an infusion of placebo. Six different doses were tested ranging from 0.015-0.300 microgram/kg/min. The infusions lasted for 2 hours and were flanked by both baseline and recovery periods. There was a significant effect of placebo on urinary sodium and chloride excretion rates but no effect on urine flow rate. In response to anaritide, the urine flow rate increased at 0.03, 0.06, 0.075, and 0.100 microgram/kg/min. The sodium and chloride excretion rates increased at all doses except the highest dose. There was no definite effect of anaritide on urinary potassium, calcium, and phosphate excretion rates. There was also no significant effect on creatinine clearance. The mean arterial pressure decreased in response to the 0.060, 0.075, and 0.100 microgram/kg/min doses. In addition, five of the patients receiving the highest dose (0.300 microgram/kg/min) had decreases in their systolic pressures to 90 mm Hg or less. In conclusion, anaritide is natriuretic and diuretic in patients with cirrhosis complicated by ascites and/or edema. Its effect, however, on arterial pressure may limit its therapeutic potential in this patient population.

Atrial Natriuretic Factor↗
PubMed1990

Treating the individual hypertensive patient: considerations on dose, sequential monotherapy and drug combinations.

For the general practitioner to be able to prescribe optimal therapy to his individual hypertensive patients, he needs accurate information on the therapeutic agents he is going to administer and practical treatment strategies. The information on drugs and drug combinations has to be applicable to the treatment of individual patients and not just patient study groups. A basic requirement is knowledge of the dose-response relationship for each compound in order to choose the optimal therapeutic dose. Contrary to general assumption, this key information is difficult to obtain and often not available to the physician for many years after marketing of a drug. As a consequence, excessive doses are often used. Furthermore, the physician needs comparative data on the various antihypertensive drugs that are applicable to the treatment of individual patients. In order to minimize potential side effects due to unnecessary combinations of compounds, the strategy of sequential monotherapy is proposed, with the goal of treating as many patients as possible with monotherapy at optimal doses. More drug trials of a crossover design and more individualized analyses of the results are badly needed to provide the physician with information that he can use in his daily practice. In this time of continuous intensive development of new antihypertensive agents, much could be gained in enhanced efficacy and reduced incidence of side effects by taking a closer look at the drugs already available and using them more appropriately in individual patients.

Antihypertensive Agents↗
PubMed1990

Prevention of renal hypertension in the rat by neuropeptide Y.

Neuropeptide Y is known to enhance blood pressure responsiveness to various constrictors, including angiotensin II, and to suppress renin secretion. This study was undertaken to assess the effect of neuropeptide Y on the development of two-kidney, one clip renal hypertension. Normotensive rats either had a silver clip placed on the left renal artery or were sham-operated upon. An osmotic minipump, which was connected via a catheter to a jugular vein, was implanted subcutaneously in all rats. These pumps delivered either neuropeptide Y (0.001 microgram/min) or saline intravenously. Eight days later, an intra-arterial catheter was inserted and the rats were studied while not anesthetized on the following day. Neuropeptide Y did not affect body weight. In clipped rats, neuropeptide Y prevented the development of hypertension and suppressed renin secretion. Neuropeptide Y significantly decreased blood pressure also in sham-operated rats, although it had no effect on plasma renin activity. These data indicate that prolonged neuropeptide Y infusion may lower blood pressure by different mechanisms, one of which is probably a suppression of renin release.

Animals↗