Search PubMed⌕ Search

Biomedical subjects

R Brunkhorst

Publications and source records attributed to R Brunkhorst.

At least 109 records · Page 6Linked to original sources
PubMed1989

[Effect of captopril therapy on sodium and water excretion in patients with liver cirrhosis and ascites].

UNLABELLED: Ascites in patients with cirrhosis of the liver frequently is refractory to diuretic treatment. It was postulated that vasoconstriction of the renal cortex, mediated by activation of the renin-angiotensin-aldosterone-system (RAAS), may be one course of the disturbed sodium- and water-excretion in these patients. We therefore investigated in 14 cirrhotic patients with ascites under constant diuretic treatment the effects of low-dose captopril therapy on urinary sodium- and potassium-excretion, body weight, abdominal girth, serum-sodium, -potassium, creatinine-clearance, plasma-renin-activity (PRA), plasma-aldosterone (PA) and mean arterial pressure (MAP). After a control period of 4 days the patients received 2 x 6.25 mg/d captopril for 5 days and 4 x 6.25 mg/d for further 5 days. Treatment was followed by a second control period without captopril. PRA increased significantly after 2 days of captopril treatment. 2 x 6.25 mg/d captopril induced a significant increase in sodium excretion and a significant decrease of body weight. MAP decreased slightly but significantly without clinical signs of hypotension. 4 x 6.25 mg/d captopril resulted in a further reduction of body weight and a further enhancement of sodium excretion. Three days after withdrawal of captopril sodium output was significantly reduced again. CONCLUSION: In cirrhotic patients low-dose captopril seems to be efficient in the treatment of ascites resistant to diuretics without causing major side effects.

Adult↗
PubMed1989

Study on the renal handling of sex dependent proteins in male rats studied by micropuncture techniques and by the isolated perfused rat kidney.

The separation of sex dependent urinary proteins of the rat (SDP) by micro-disc electrophoresis results in at least eight well defined protein bands with differing molecular weights. The hepatic origin of a sex dependent urinary protein, named alpha 2u-globulin, has been demonstrated before by other authors applying immunological methods. In the present study, it could been shown that SDP circulate in the plasma at a concentration of 23.8 mg/l. The origin of those protein bands which appear typically upon electrophoresis was still under dispute because they could not been demonstrated in proximal tubular fluid. The present study confirms the extrarenal source of SDP and suggests identity with alpha 2u-globulin. The attempt to track down SDP from plasma to excreted urine demonstrated that, in contrast to proximal fluid, samples from nephron parts distal to the loop of Henle contain large amounts of SDP. An isolated kidney model was used to determine the sieving coefficient and tubular reabsorption of SDP, obtained from male rat urine. We have found a correlation between the sieving coefficient and the molecular weight of SDP. The sieving coefficient ranged from 0.375 to 0.834. The tubular reabsorption which has been determined with an isolated kidney perfused with albumin and erythrocytes also showed variation with regard to molecular weight and was 61.7%, on average.

Alpha-Globulins↗
PubMed1989

An increase in the ratio of thromboxane A2 to prostacyclin in association with increased blood pressure in patients on cyclosporine A.

The aim of this study was to determine the effect of two years of treatment with cyclosporine A on blood pressure and the rates of secretion into the circulation of the vasoconstrictor thromboxane A2 and the vasodilator prostacyclin. Seven patient suffering from multiple sclerosis took part. Their blood pressures and urinary concentrations of 2,3-dinor-thromboxane A2 (a major urinary metabolite of thromboxane A2) and of 2,3-dinor-6-keto-prostaglandin F1 alpha (the major urinary metabolite of prostacyclin) were determined at the end of two years of treatment with cyclosporine A, and once again three months after cessation of this treatment. No other drugs were given during or after cyclosporine A. Mean arterial blood pressure was 113 +/- 5 mmHg (mean +/- SEM) during the cyclosporine A treatment, but fell to 94 +/- 4 mmHg after the three-month's wash-out period. Urinary excretion of the thromboxane metabolite decreased slightly from 674 +/- 150 pg.mg-1 creatinine during cyclosporine A therapy to 503 +/- 90 pg.mg-1-creatinine after the end of therapy. At the same time the prostacyclin metabolite increased significantly from 82 +/- 17 pg.mg-1 creatinine to 113 +/- 23 pg.mg-1 creatinine (P less than 0.05). The ratio of 2,3-dinor-thromboxane B2 to 2,3-dinor-6-keto-prostaglandin F1 alpha (taken as a measure of vasoconstrictor prostanoid activity) fell significantly from 8.4 +/- 0.8 4.7 +/- 0.6 (P less than 0.005). The shift in prostanoid production observed during cyclosporine A treatment could be one causal factor for the hypertensive and thromboembolic events associated with the use of this drug.

6-Ketoprostaglandin F1 alpha↗
PubMed1989

Erythropoietin in polycystic kidneys.

Erythropoietin (EPO) formation in kidneys of 18 patients with autosomal dominant polycystic kidney disease (ADPKD) was investigated. In 12 patients on hemodialysis and in 6 patients with preterminal renal failure serum, EPO was 29 +/- 7 and 16 +/- 1.5 mU/ml and hemoglobin concentrations were 11.0 +/- 0.6 and 12.7 +/- 1.2 g/dl, respectively. Cyst fluid from a total of 357 renal cysts was obtained by either in vivo aspiration or immediately after nephrectomy. The cysts contained variable concentrations of bioactive EPO from undectable values up to 3.2 U/ml. A pronounced enrichment of EPO was observed in cysts with sodium concentrations greater than 100 mmol/liter, suggesting an association with proximal tubular malformations. The EPO concentrations in the cysts were neither correlated with the protein concentration nor with the oxygen pressure of the cyst fluid. Using a cDNA probe for human EPO, mRNA for EPO was localized in stroma cells of the cyst walls by an in situ hybridization technique. Our findings suggest that single interstitial cells juxtaposed to proximal tubular cysts may produce EPO independent of the oxygen pressure inside the cysts, which ameliorates the anemia during end-stage polycystic kidney disease.

Animals↗
PubMed1989

[Clinical syndromes with liver and kidney involvement in children and adults].

Multiple pathogenetic mechanisms can lead to dysfunctions or malformations of the liver and kidneys in children and adults. The association of renal and hepatic abnormalities can be found in different congenital malformation syndromes. Hereditary metabolic disorders are capable of alternating liver and kidney function. Immunologic, toxic and septic diseases may damage both organ systems. In patients with liver cirrhosis, both glomerular and tubular dysfunctions can be observed. In the course of liver transplantations, an increased rate of renal dysfunction was observed. This survey summarizes the main clinical syndromes of renal involvement associated with liver disease.

Adult↗
PubMed1988

Effect of treatment with recombinant human erythropoietin on peripheral hemodynamics and oxygenation.

Slow progressive improvement of renal anemia from 21 up to 33% hematocrit by rhEPO treatment results in an increase of tissue oxygenation as indicated by a rise of the transcutaneous oxygen pressure. In normotensive patients this was accompanied by an increase in MAP (delta 6 mm Hg) within the normal range and a significant fall of the regional blood flow. These hemodynamic changes are caused by increases of the regional and presumably also of the total peripheral vascular resistance. Most likely the increase in total peripheral vascular resistance represents an autoregulatory event triggered by the rising tissue oxygenation. From the present data it is difficult to estimate to what extent the observed rise in hematocrit affects peripheral vascular resistance also via an increase of blood viscosity.

Adult↗
PubMed1988

Heterogeneity of glomerular barrier function in early adriamycin nephrosis of MWF rats.

Adriamycin (ADR), selectively toxic to glomerular epithelial cells, was administered (5 mg/kg BW, i.v.) to MWF/Ztm rats to study its early effects on glomerular barrier function with respect to albumin and high molecular weight (HMW) proteins. After 7 days of ADR incubation (glomerular filtration rate remains unchanged), protein excretion was significantly increased in treated rats. The proteinuria was due to a nonselective glomerular lesions resulting in an increase in both, but not a changed ratio of HMW proteins to albumin. However, this ADR-induced proteinuria seen in the final urine was not confirmed by free-flow micropuncture studies of superficial glomeruli. The albumin and HMW protein concentrations in samples taken from Bowman's capsular space of ADR-treated rats did not significantly differ from control samples. These data suggest that cortical nephrons are less sensitive to ADR than juxtamedullary nephrons.

Albuminuria↗
PubMed1986

[Ultrasound-guided fine needle puncture of the abdominal organs: indications, results, risks].

2072 patients underwent ultrasonically guided fine-needle biopsy. 1384 patients could be assessed with regard to the final diagnosis. 854 patients underwent fine-needle biopsy of the liver, 322 of the pancreas and 218 of retroperitoneal lesions. The effective sampling rate was 97% for liver biopsies, 86% for pancreas biopsies and 87% for the biopsy of the retroperitoneum. The sensitivity for the detection of malignancies was 90% in liver biopsies, 69% in pancreatic biopsies and 85% in biopsies of the retroperitoneum. The specificity of cytological findings was 100%. Complications occurred in 13 cases. There were two fatalities due to of bleeding, resulting in a complication rate of 0.6% and a lethality of 0.1% of all biopsied patients. The biopsy of the liver proved most dangerous with a complication rate of 1.4%. The bleeding risk of a haemangioma (2.5%) was nearly the same as the bleeding risk of a malignant liver tumour (1.5%).

Abdominal Neoplasms↗
PubMed1986

Single nephron hyperfiltration and proteinuria in a newly selected rat strain with superficial glomeruli.

Alterations in glomerular permeability were studied in female MWF/Ztm rats, newly selected from the Munich Wistar rats with a high number of superficial glomeruli. This strain is characterized by a diminished number of functioning nephrons, an elevated arterial blood pressure and a high proteinuria averaging 24 mg/24 h. Samples of Bowman capsular space (BCS) obtained by free-flow renal micropuncture techniques with pressure control were analyzed for albumin and high-molecular-weight (HMW) proteins by ultramicrodisc electrophoresis. The measured mean albumin and HMW protein concentration in BCS were 1.72 g/l and 0.66 g/l, respectively. The glomerular filtration rate (GFR) averaged 0.74 ml/min/g kidney weight and the single nephron GFR (SNGFR) 48 nl/min. Ultrastructural studies revealed focal bleb-like alterations of the podocytes as has been observed in hyperfiltration states. We suggest that the reduced number of functioning nephrons in the kidneys of these rats could induce glomerular hyperfiltration and permselectivity changes, which cause a high glomerular protein leakage.

Animals↗
PubMed1984

Effect of diuretics on the tubuloglomerular feedback response.

To study the influence of diuretics on the tubuloglomerular feedback mechanism, early proximal stop-flow pressure (SFP) was measured during loop exposure to different drug concentrations. SFP was recorded continuously during arrested flow and at a perfusion rate of 50 nL/min. The perfusate consisted of isotonic saline, to which varying amounts of furosemide. bumetanide, piretanide, or hydrochlorothiazide were added to obtain final concentrations between 10(-6) and 10(-4)M. The loop diuretics furosemide, bumetanide, and piretanide showed inhibition: an inverse log-linear relation between the luminal concentration and the respective feedback response. No differences between the dose-response curves of furosemide, bumetanide, or piretanide could be demonstrated. The effective concentration range was between 10(-6) and 10(-4)M, the mean effective dose (ED50) was close to 10(-5)M for each of them. In contrast, hydrochlorothiazide did not alter the feedback response. The effect of loop diuretics was rapidly and repeatedly reversible.

Animals↗
PubMed1983

Dose-related effects of furosemide, bumetanide, and piretanide on the thick ascending limb function in the rat.

To assess the action of piretanide, bumetanide, and furosemide on the thick ascending limb of Henle's loop, perfusion experiments were performed on rat kidneys, using a recently developed conductivity microprobe for the analysis of distal tubular fluid. Surface nephrons were perfused downstream from a solid paraffin block through Henle's loop with isotonic saline solution containing either 10(-6), 3 X 10(-6), or 10(-5) mol/L piretanide, bumetanide, or furosemide, respectively. For control values, diuretic-free saline was used. Conductivity measurements of early distal tubular fluid were performed in situ with a conductivity microprobe and were recorded continuously during variations of loop perfusion rate. A recently described micro-stop-flow technique was used to measure the conductivity of fluid emerging from the ascending limb, thereby evaluating the amount of sodium chloride reabsorbed. A significant electrolyte transport inhibition occurred within the concentration range between 10(-6) and 10(-4) M. Bumetanide and piretanide were slightly more effective than furosemide. Luminal diuretic concentrations of 10(-6) M or below were without influence on electrolyte reabsorption. Concentrations of 10(-4) M resulted in complete inhibition of the diluting segment electrolyte transfer.

Absorption↗