15 research outputs found
Micropuncture studies of proximal tubule albumin concentrations in normal and nephrotic rats
A B S T R A C T The concentration of serum albumin in proximal tubule fluid of normal rats and animals with aminonucleoside nephrosis was studied using renal micropuncture techniques. Albumin was quantitated by an ultramicrodisc electrophoresis method capable of measuring 3 X 10'" g of albumin, in 10 nl volumes. With this sensitivity., only small samples of tubule fluid were required for analysis. Collectifn times could be kept short, therefore decreasing the opportunity for sample contamination with extraneous serum albumin. The measured mean concentration of albumin in proximal tubule fluid (1 mg/100 ml in females and 0.7 mg/ 100 ml in males) was somewhat lower than values reported by others, but even these values are apt to have been artifactually high as a result of animal preparation and trace contamination of samples during micropuncture. Rats injected with aminonucleoside of puromycin 4 days earlier, showed a significant increase in tubulefluid albumin concentration coincident with a fall in serum albumin concentration and a 43-fold increase in urine albumin concentration. Tubular absorption of albumin was small relative to that of water. Although albumin filtration was significantly increased over that in normal animals, the glomerular basement membrane still served as a highly efficient barrier to albumin transfer
Epoprostenol (PGI2, Prostacyclin) During High‐Risk Hemodialysis: Preventing Further Bleeding Complications
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/97231/1/j.1552-4604.1988.tb03222.x.pd
Effect of dithiothreitol on mercuric chloride- and uranyl nitrate-induced acute renal failure in the rat.
Micropuncture studies of proximal tubule albumin concentrations in normal and nephrotic rats
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Characterization of the Renin-Angiotensin System in the Isolated Perfused Rat Kidney
Most previous studies using the isolated perfused kidney model to assess the mechanisms governing renin release have utilized single-point determinations of media renin content as an estimate of renin release rate. In the present study the dynamics of renin release were examined under standardized conditions of perfusion, with simultaneous evaluations of changes in renal function. Media samples were collected at 5-min intervals. Renin release rate was characterized by an initial progressive increase which achieved a constant value of 67 ng/ h/min/g only after 45 min of perfusion. Consequently, the accumulation of renin within the media does not become linear until 45 min of perfusion. Simultaneous determinations of various parameters of renal function disclosed that neither GFR, renal sodium handling nor indices of distal delivery correlated with renin release. However, the renin-angiotensin system is not physiologically intact since the standard perfusate utilized in the present study was demonstrated to lack both renin substrate and converting enzyme. The present studies demonstrate that renin release is curvilinear and that experimental errors may occur if sampling is not restricted to the stable phase of perfusion
Superficial and Deep Juxtaglomerular Apparatus Renin Activity of the Rat Kidney EFFECT OF SURGICAL PREPARATION AND NaCl INTAKE
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Comparison of propranolol or hydrochlorothiazide alone for treatment of hypertension: III. Evaluation of the renin-angiotensin system
In this study, the relation between renin activity and therapeutic response to hydrochlorothiazide or propranolol was studied. Patients with a diastolie blood pressure of 95 to 114 mm Hg were treated with propranolol (40 to 320 mg twice daily) or hydrochlorothiazide (25 to 100 mg twice daily). The initial renin profiles were: low, 56 percent (n = 300); normal, 33 percent (n = 174); high, 11 percent (n = 60). A greater incidence of tow and fewer high renin profiles (p < 0.001) were observed in blacks. After furosemide administration (40 mg intravenously), 55 percent of patients (n = 291) had a low renin response and 45 percent (n = 240) had a normal renin response. No correlation between renin profile and renin response was observed, although low renin response and low renin profile occurred more frequently in older patients. Hydrochlorothiazide administration resulted in a greater decrement in diastolic blood pressure (p < 0.05) in the total group. Irrespective of renin activity, both hydrochlorothiazide and propranolol reduced diastolic blood pressure. When renin profile was considered, no significant variation in response to hydrochlorothiazide therapy was observed, and there was a greater reduction in diastolic blood pressure in the patients with a high renin profile receiving propranolol. In comparing therapeutic response, patients with a low renin profile had a better response to hydrochlorothiazide, and propranolol was more effective in patients with a high renin profile. The anticipated effect of therapy on plasma renin activity was observed. Although these results are consistent with a volume-vasoconstrictor analysis of hypertension, the results of therapy could not have been prejudged from renin profile or responsivity. The slight differences observed do not warrant the expense of renin determinations when a simple determination of therapeutic response is sufficient