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Biomedical subjects

J H Bauer

Publications and source records attributed to J H Bauer.

At least 91 records · Page 5Linked to original sources
PubMed1984

Model prediction of plasma volume change induced by hemodialysis.

We simulated the change in plasma volume by hemodialysis by combining two models for transcapillary and transcellular fluid exchange. Model predictions of the plasma volume change were found to be in good agreement with the measured values in five patients who were studied during 4-hour hemodialysis at a constant ultrafiltration rate of 0.5 L/hr using three different dialysate sodium concentrations: 7% below, 7% above, and equal to the predialytic serum concentration. The measurements and model predictions indicate that the decrease in plasma volume is smaller in high sodium dialysis than in normal and low sodium dialyses. Because model predictions were consistent with measurements, this model should be useful in clinical practice to quantitatively analyze the change in plasma volume during hemodialysis and to relate it with hypovolemic hypotension.

Blood Proteins↗
PubMed1984

Effects of indoramin therapy on BP, renal function, and body fluid composition.

Indoramin hydrochloride is a new alpha 1-adrenoceptor antagonist. Eleven hypertensive men in whom the BP was normalized with indoramin underwent assessment of renal function, renal hemodynamics, and body fluid composition following short-term (three to six weeks), long-term (five to six months), and withdrawal (two weeks) therapy. Short-term indoramin therapy produced a 28% increase in glomerular filtration rate, a 24% increase in effective renal plasma flow, and a 31% decrease in renal vascular resistance. Although urine flow rate and free water clearance were unchanged, fractional sodium excretion decreased 38%. Long-term indoramin therapy was associated with qualitatively similar renal effects, but the changes did not achieve statistical significance. Plasma volume was increased only during short-term therapy; however, body weight was increased following both short- and long-term therapy. Indoramin effectively lowers BP without producing deleterious renal effects.

Aged↗
PubMed1984

Effects of prazosin therapy on BP, renal function, and body fluid composition.

To our knowledge, the long-term effects of prazosin hydrochloride, an alpha 1-adrenoceptor antagonist, on renal function and body fluid composition have not been previously reported. Fourteen hypertensive men in whom the BP was normalized with prazosin monotherapy, underwent assessment of renal function and body fluid composition following short-term (three to six weeks), long-term (five to six months), and withdrawal (two weeks) therapy. Neither short- nor long-term prazosin therapy had any adverse effect on the glomerular filtration rate or effective renal plasma flow. Renal vascular resistance was decreased 14% during short-term therapy, but not during long-term therapy. Urine flow rate, urine osmolality, free water clearance, and fractional sodium and potassium excretions were statistically unchanged throughout drug therapy. Plasma volume and extracellular fluid volume were increased following both short- and long-term therapy. Long-term prazosin monotherapy effectively lowers BP without resulting in drug tolerance, however, sodium retention probably limits its antihypertensive effectiveness.

Blood Pressure↗
PubMed1983

Effects of maternal state on the responsiveness to nest odors of hooded rats.

Two experiments were designed to determine if pregnant and lactating rats are differentially attracted to their own bedding at various stages of the reproductive cycle and whether they will discriminate between their own nest materials and those of virgins and other lactating animals. We found that from just before birth until the second week postpartum, rats are attracted to their own bedding but do not differentiate between their own and that of other maternal animals. It is suggested that the responsiveness to nest odors in prepartum pregnant animals is a result of hormonal events prior to parturition. In addition, early maternal activities are thought to be facilitated by changes in responsiveness to olfactory stimuli and also by the presence of an attractant which contributes to nest odors.

Animals↗
PubMed1983

A simulation study on transcellular fluid shifts induced by hemodialysis.

A computer-based model has been developed to predict the changes in serum sodium, urea concentration, and osmolality as well as transcellular fluid distribution which occur during hemodialysis. Sodium and urea transfers across the dialyzer membrane and transcellular fluid shifts in response to the sodium transfer were modeled assuming that only sodium and its accompanying anions are important as effective osmotic substances in extracellular fluid. Model predictions were consistent with values measured in five patients who were studied on hemodialysis at three different dialysate sodium concentrations equal to 7% below and 7% above the predialysis serum concentration. The measurements and model predictions indicate that serum sodium concentration decreases and intracellular fluid volume increases in dialyses with dialysate Na+ concentration used in conventional hemodialysis, whereas serum sodium concentration increases and intracellular volume decreases in high sodium dialyses. An analysis of model predictions indicates that a reasonable estimation of total body water and the intracellular to extracellular volume ratio enables us to accurately predict the magnitude of transcellular fluid shifts induced by hemodialysis as well as the postdialysis serum sodium concentration and osmolality.

Blood Urea Nitrogen↗
PubMed1983

Hypokalemia in acute myelogenous leukemia.

Forty-two patients with acute myelogenous leukemia or one of its variants were studied at diagnosis to determine the incidence and cause(s) of hypokalemia. Forty-three percent of patients were hypokalemic, and an inappropriate renal loss of potassium was noted. This potassium wastage could not be explained by antibiotic-induced renal tubular dysfunction, lysozymuria, or alterations in renin-aldosterone secretion.

Aldosterone↗
PubMed1983

Prediction of postdialysis serum sodium concentration and transcellular fluid shift without measuring body fluid volumes.

The postdialysis levels of serum sodium concentration, urea concentration, and osmolality, as well as the magnitude of both transcellular fluid shifts and sodium removal, were predicted based on computer modeling without measuring body fluid volumes. A 4-h hemodialysis was performed in five patients at a constant ultrafiltration rate of 0.5 L/h using dialysate with normal (141 mEq/L) or high (150 mEq/L) Na+ concentration. The serum sodium concentration, urea concentration, and osmolality, as well as intracellular and extracellular fluid volumes, were determined before and after hemodialysis. The model predictions without measurement of body fluid volumes were in excellent agreement with measured values, suggesting clinical validity. The model may be useful in clinical practice to control the postdialysis levels of sodium and water content by computerized hemodialysis.

Adult↗
PubMed1983

Effects of propranolol therapy on renal function and body fluid composition.

Fourteen hypertensive men underwent assessment of renal function and body fluid composition following short-term (three to six weeks), long-term (five to six months), and withdrawal (two weeks) of propranolol hydrochloride monotherapy for the treatment of hypertension. Results indicate that propranolol had little effect on glomerular filtration rate (less than 10% decrease); changes that did occur were directly correlated with changes in effective renal plasma flow. Propranolol therapy decreased effective renal plasma flow 14% and renal blood flow 15% during long-term therapy; decreases in renal perfusion persisted following withdrawal of therapy. Propranolol therapy was neither antidiuretic nor antinatriuretic; propranolol had no effect on urine osmolality, free water clearance, sodium clearance, or fractional sodium excretion. Furthermore, propranolol therapy did not expand plasma volume, extracellular fluid volume, or total body water. Finally, propranolol therapy had no effect on the renal handling of potassium or on serum potassium concentration.

Blood Pressure↗
PubMed1983

Effects of guanabenz therapy on renal function and body fluid composition.

Guanabenz acetate is a new centrally acting alpha 2-adrenergic agonist. Seventeen hypertensive men, in whom BP was normalized with guanabenz, underwent assessment of renal function, renal hemodynamics, and body fluid composition following short-term (three to six weeks), long-term (five to six months), and withdrawal (two weeks) therapy. Guanabenz therapy caused a modest but reversible reduction in glomerular filtration rate (12% to 18%), effective renal plasma flow (9% to 17%), and renal blood flow (12% to 20%). Renal vascular resistance was unchanged. Guanabenz therapy had no significant natriuretic or antinatriuretic effects in patients with an effective BP decrease, although it had the ability to produce and sustain a water diuresis. Guanabenz therapy was not associated with salt and water increases within body fluid compartments. Guanabenz, in some patients, is an effective monotherapy for the treatment of hypertension.

Blood Pressure↗
PubMed1982

Renal function studies in man with advanced renal insufficiency.

In subjects with advanced renal insufficiency, the average of the creatinine and urea clearances ([Ccr + Cur]/2) is frequently used as an indicator of glomerular filtration rate (GFR). To test the accuracy of this method, 31 subjects with inulin clearance (Cin) less than 20 ml/min/1.73 m2 underwent simultaneously timed creatinine, urea, and inulin clearances. The results indicated that: (1) Ccr correlated positively with Cin; mean fractional excretion of creatinine (Ccr/Cin) was 1.5; (2) Cur correlated positively with Cin; in contrast to creatinine, the fractional excretion of urea (Cur/Cin) correlated negatively with Cin; (3) in 10 of 12 subjects with Cin less than 8 ml/min 1.73 m2, the Cur/Cin was greater than 1, suggesting that tubular secretion may have occurred; and (4) the (Ccr + Cur)/2 correlated positively with Cin and was the best clinical indicator of GFR.

Adult↗
PubMed1982

Clinical appraisal of creatinine clearance as a measurement of glomerular filtration rate.

The plasma creatinine and the endogenous creatinine clearances are two of the most commonly used tests in clinical medicine to assess glomerular filtration rate. However, the contribution that tubular secretion of creatinine has on the total endogenous creatinine clearance (Ccr) is not generally known, nor are the effects renal insufficiency has on the tubular secretion of creatinine. To assess the above, 123 human subjects, with a wide range of renal function, underwent simultaneous Ccr and inulin clearances (Cin). The results indicate that: (1) Ccr approximates Cin only when Cin is normal; (2) a normal plasma creatinine of Ccr is not measurable evidence of a normal Cin; and (3) with progressive decline in Cin, there is progressive increase in the tubular secretion of creatinine, leading to a progressive disparity between Ccr and Cin.

Adult↗
PubMed1982

Body-fluid composition in normal and hypertensive man.

1. Erythrocyte mass, plasma volume (PV), extracellular fluid volume (ECFV) and total body water were simultaneously measured in 30 normotensive and 30 normal-renin hypertensive Caucasian male subjects for accurate determination of the presence or absence of a disorder(s) in body-fluid composition in hypertension. 2. The results indicate that plasma volume and total blood volume are lower in hypertensive subjects than in normotensive control subjects. The PV comprised 19% of the ECFV in both control and hypertensive subjects. 3. ECFV was lower in hypertensive subjects than in normotensive control subjects; the PV and interstitial fluid components of the ECFV were reduced by similar proportions. The ECFV, furthermore, comprised a smaller portion of the total body water in hypertensive subjects than that in control subjects. 4. We conclude that in the hypertensive state there is a reduction in the ECFV, but that there is no change in the partition of the ECFV between the plasma and interstitial components.

Adult↗
PubMed1982

Rapid control of severe hypertension with minoxidil.

We studied nine symptomatic patients whose diastolic BP exceeded 120 mm Hg two hours after receiving a combination of 40 mg of oral propranolol hydrochloride and 40 mg of oral furosemide. Systemic and pulmonary hemodynamics were measured before and after a 20-mg loading dose of oral minoxidil. A booster dosage of 5 to 20 mg of minoxidil was given at four hours if the diastolic BP exceeded 100 mm Hg. There was a progressive and significant reduction of systemic vascular resistance and systolic diastolic BP during the period of hemodynamic monitoring. The decrease in systemic vascular resistance occurred without notable change in cardiac output or pulmonary wedge pressure. The results indicate that an orally administered regimen of propranolol, furosemide, and loading-booster doses of minoxidil produces prompt, progressive, and sustained BP reduction due to vasodilation in patients with severe hypertension who require prompt (but not immediate) BP control.

Adult↗
PubMed1982

Renal function and hemodynamic studies in low- and normal-renin essential hypertension.

Reduced renal blood flow has been suggested to be both a cause and a consequence of essential hypertension. To test these hypotheses, techniques for the clearance of inulin (Cin) and p-aminohippurate (Cpah) were used to assess renal function and hemodynamic measurements in patients with mild and moderate normal-renin and low-renin essential hypertension and in age-matched normotensive subjects. In our study, compared with age-matched control subjects, normal-renin hypertensive subjects younger than 42 years with basal diastolic BPs less than 100 mm Hg had normal glomerular filtration (Cin) and effective renal plasma flow (Cpah), filtration fraction (Cin/Cpah), and renal blood flow (Cpah/1-hematocrit value). The mean arterial pressure (MAP) and renal vascular resistance (MAP/renal blood flow) were increased. In contrast, compared with age-matched control subjects, normal-renin hypertensive subjects older than 42 years with basal diastolic BPs less than 100 mm Hg and greater than 100 mm Hg had a decreased Cpah and an increased filtration fraction. The MAP was increased, the renal blood flow decreased, and the renal vascular resistance notably increased. Subjects with low-renin essential hypertension had renal function and hemodynamic patterns indistinguishable from those of age matched normal-renin hypertensive subjects with similar basal diastolic BPs. These data suggest that in early normal-renin essential hypertension, the increase in systemic BP is not caused by renal circulatory disturbances. Increased renal vascular resistance, however, may lead to subsequent vascular functional or structural changes, ultimately decreasing effective renal plasma flow but at a rate disproportionate to the glomerular filtration rate.

Adult↗
PubMed1981

Effects of diuretic and propranolol on plasma lipoprotein lipids.

Ticrynafen (TCNF), a nonthiazide diuretic, has been reported to be nonhyperlipidemic. To define the effects of these drugs on plasma lipoproteins, experiments were performed in hypertensive subjects after placebo therapy, 4 wk after therapy with either hydrochlorothiazide (HCTZ) or TCNF, 3 mo after diuretic with propranolol, and 1 mo after therapy with propranolol alone. Plasma lipoproteins were separated by ultracentrifugation and the lipid fractions isolated by extraction and silicic acid thin-layer chromatography. Plasma low-density lipoprotein (LDL) total cholesterol fell and high-density lipoprotein (HDL) total cholesterol rose in subjects receiving TCNF. TCNF had no effect on plasma low-density lipoprotein (VLDL) triglyceride or phospholipid. There was no significant changes in LDL or HDL total cholesterol in subjects on HCTZ. HCTZ tended to increase plasma VLDL triglyceride and phospholipid. The addition of propranolol to either diuretic had no effect on LDL or HDL total cholesterol but increased VLDL triglyceride, especially in subjects on HCTZ. Propranolol alone had no effect on any of the lipids measured.

Adult↗
PubMed1981

Selective renal artery embolization for control of biopsy-induced bleeding.

Two cases of selective renal artery embolization for control of bleeding induced by arteriovenous malformation are described. Both cases occurred after percutaneous renal biopsy and involved massive hematuria, unresponsive to conservative treatment. Arteriography in both cases demonstrated an arteriovenous fistula in the area of the biopsy, and selective embolization with an artificial clot resulted in prompt cessation of bleeding. In one case, follow-up angiograms showed a minimal anatomic defect, and renal function studies were unchanged. Selective renal artery embolization is an acceptable method for correcting bleeding due to biopsy-induced arteriovenous malformation.

Adult↗
PubMed1981

Renal function abnormalities induced by marathon running.

To assess renal function changes induced by marathon racing in asymptomatic runners, we studied them before, six hours after, and one week after warm and cold weather marathons (26.2 miles [42 km]). Standard serum electrolytes, creatine phosphokinase (CPK), urinalysis, urinary myoglobin, and renal function tests (para-aminohippurate [PAH], inulin, and true creatinine clearances) were performed. After rehydration to their prerace weight, the subjects showed no postrace change in serum electrolytes. The CPK rose postrace and was two to three times higher in the warm weather runners than in the cold weather runners. All postrace urinalyses were grossly abnormal. Urinary myoglobins were positive postrace in warm weather runners and negative in cold weather runners. Warm weather runners showed a 50% decline in inulin clearance postrace but maintained PAH clearance. At one week, inulin clearance returned to baseline but fractional excretion of creatinine was below unity. In contrast, cold weather runners showed no change in inulin and PAH clearances postrace or at one week, but fractional excretion or creatinine postrace was less than unity returning to baseline at one week. We conclude that renal function abnormalities occur in marathon runners and that the severity of the abnormality is temperature-dependent.

Acute Kidney Injury↗