Search PubMed⌕ Search

Biomedical subjects

V Arroyo

Publications and source records attributed to V Arroyo.

At least 199 records · Page 11Linked to original sources
PubMed1983

[Specificity of the determination of urinary kallikrein activity using an amidolytic assay].

The specificity of a method for the determination of the urinary kallikrein activity based on the amidolytic hydrolysis of the synthetic substrate H-D-valyl-leucyl-arginine-p-nitroanilide has been studied. Results show a good specificity for kallikrein. The amidolytic activity was totally inhibited by aprotinin. The urinary amidolytic activity showed identical dependence on changes in the ionic strength and pH of the incubation medium as the highly purified kallikrein. The sensitivity of the assay was 0.6 nkat/l. The intra-assay coefficient of variation was 4% and the inter-assay coefficient of variation was 10%. The percentage of recovery was between 100 and 110% indicating that no activators or inhibitors of the kallikrein activity on this substrate were present in the urinary samples. Values obtained in presumably healthy subjects were 0.14 +/- 0.08 pkat/s in man (range: 0.05 - 0.27 pkat/s) and 0.49 +/- 0.11 pkat/s in rat (range: 0.35 - 0.58 pkat/s).

Adult↗
PubMed1983

Randomized comparative study of efficacy of furosemide versus spironolactone in nonazotemic cirrhosis with ascites. Relationship between the diuretic response and the activity of the renin-aldosterone system.

Loop and distal diuretics are the basic drugs for the treatment of ascites. Although pharmacologic studies indicate that the natriuretic potency of loop diuretics is much greater than that of distal diuretics, there are no studies comparing the efficacy of these drugs in cirrhosis. Forty nonazotemic cirrhotic patients with ascites and avid sodium retention were randomly allocated into two groups. Group 1 contained 21 patients treated with furosemide; group 2 contained 19 patients treated with spironolactone. The initial doses were 80 and 150 mg/day, respectively. These doses were increased to 160 and 300 mg/day, respectively, if there was no response. Cases not responding to furosemide and spironolactone were later treated with spironolactone and furosemide, respectively. In group 1, 11 of the 21 patients responded to furosemide, while in group 2, 18 of the 19 patients responded to spironolactone (p less than 0.01). Of the 10 patients in group 1 not responding to furosemide, 9 responded later to spironolactone. The diuretic response to furosemide and spironolactone was related to the activity of the renin-aldosterone system. Patients with higher renin and aldosterone did not respond to furosemide and required 300 mg/day of spironolactone to achieve a diuretic response. These results indicate that (a) at the dosages used in the study, spironolactone is more effective than furosemide in nonazotemic cirrhosis with ascites, and (b) the activity of the renin-aldosterone system influences the diuretic response to furosemide and spironolactone in these patients.

Ascites↗
PubMed1983

Acetylsalicylic acid suppresses the renal hemodynamic effect and reduces the diuretic action of furosemide in cirrhosis with ascites.

To investigate if lysine acetylsalicylate influences the hemodynamic and diuretic responses to furosemide in cirrhosis, 21 nonazotemic patients with ascites were studied. In 8 patients (group 1), the renal plasma flow and glomerular filtration rate were serially measured before and during three 30-min periods after the i.v. administration of lysine acetylsalicylate (450 mg). In 7 patients (group 2), renal plasma flow, glomerular filtration rate, urine volume, and sodium excretion were measured before and during three 20-min periods after the i.v. administration of furosemide (40 mg). After a 45-min period in which urinary losses were restored, a similar study was performed before and after a second injection of furosemide (40 mg). Six patients (group 3) were studied with an identical protocol as group 2, except that the second injection of furosemide was preceded by the administration of lysine acetylsalicylate (450 mg). In 6 patients of group 1, lysine acetylsalicylate caused a marked and reversible reduction of renal plasma flow and glomerular filtration rate. In groups 2 and 3, the i.v. injections of furosemide alone produced a significant increase in renal plasma flow and glomerular filtration rate, and a marked diuresis and natriuresis. In patients of group 3, pretreatment with lysine acetylsalicylate suppressed the renal hemodynamic effect and markedly reduced the diuretic effect of the second injection of furosemide. Lysine acetylsalicylate did not cause the appearance of renal insufficiency in any of these patients. These results suggest that prostaglandins are involved in the renal response to furosemide in cirrhosis with ascites and that furosemide protects these patients from developing renal insufficiency after acute administration of nonsteroidal antiinflammatory agents.

Aspirin↗
PubMed1983

Radioimmunoassay for arginine-vasopressin in cold ethanol extracts of plasma.

A radioimmunoassay for arginine-vasopressin in human plasma with use of a commercially available antibody was developed and evaluated. The hormone was extracted from plasma with cold 98% ethanol, which showed a significantly higher (p less than .001) and more precise recovery than with the acetone-ether procedure (65.3 +/- 3.7% vs 50.8 +/- 6.0%, respectively). The sensitivity was 0.31 pg per tube. Results for normal subjects in different physiological conditions and in patients with diabetes insipidus and inappropriate antidiuretic hormone secretion showed the good reliability of the method.

Acetone↗
PubMed1981

Intracellular and exchangeable potassium in cirrhosis. Evidence against the occurrence of potassium depletion in cirrhosis with ascites.

The intracellular potassium content of leukocytes, the extracellular fluid volume (82Br space), and exchangeable potassium were determined in 28 patients with cirrhosis of the liver (18 with ascites) and in 15 hospitalized controls. No intracellular potassium depletion could be identified in these patients. Leukocyte potassium was similar in cirrhotic patients with and without ascites (355.9 +/- 25.3 and 348.1 +/- 31.9 mEq/kg of dry solids, respectively) and in hospitalized controls (359.7 +/- 27.4) (mean +/- SD). The extracellular fluid volume was similar in controls and cirrhotics without ascites, but markedly increased in cirrhotics with ascites. The exchangeable potassium (mEq/kg of body weight) was similar in nonascitic cirrhotics and in hospitalized controls, but significantly lower in patients with cirrhosis and ascites. However, when the estimated weight of the extracellular fluid volume was substrated from the total body weight, thus obviating the influence of the increased extracellular fluid volume of ascitic patients in the body weight, the exchangeable potassium (mEq/kg of "corrected" body weight) was similar in cirrhosis with ascites (52.9 +/- 6.7 mEq/kg), nonascitic cirrhotics (55.8 +/- 6.1 mEq/kg) and hospitalized controls (55.0 +/- 8.3 mEq/kg), and a significant correlation was obtained between the exchangeable potassium and the leukocyte potassium content. In five patients, the measurements were repeated after relieving ascites with diuretics. No change was observed in the leukocyte potassium, but exchangeable potassium (mEq/kg of body weight) increased, reaching values not significantly different from controls or nonascitic cirrhotics. The exchangeable potassium (mEq/kg of "correct" body weight) did not change. Our results strongly suggest that potassium depletion was not present in the series of cirrhotic patients studied.

Aged↗
PubMed1981

Effect of angiotensin-II blockade on systemic and hepatic haemodynamics and on the renin-angiotensin-aldosterone system in cirrhosis with ascites.

We have studied the effect of angiotensin-II blockade with saralasin on the cardiovascular and hepatic hemodynamics and on the renin-angiotensin-aldosterone system in fourteen patients with cirrhosis and ascites. Control measurements showed that most of the patients had a low mean arterial pressure, high plasma volume, normal or high cardiac index, low peripheral resistance and high plasma renin activity and aldosterone concentration. The wedged hepatic venous pressure was increased in each patient and the estimated hepatic blood flow was normal in most of them. Overall, saralasin induced a significant reduction of the mean arterial pressure, cardiac index and peripheral resistance. The decrease of the peripheral resistance was greater than that of the cardiac index. Six of the patients developed a marked reduction of the mean arterial pressure with low doses of saralasin (1--2.5 microgram/kg/min), and they had significantly higher plasma renin activity and lower mean arterial pressure than the remaining eight patients who showed a slight or no hypotensive response in spite of infusing saralasin up to a dose of 10 micrograms/kg/min. Overall, the decrease of the mean arterial pressure correlated directly with the baseline values of plasma renin activity. Angiotensin-II blockade induced a significant reduction of the wedged hepatic venous pressure. The hepatic blood flow did not show any significant change. The decrease of the wedged hepatic venous pressure was directly related to the reduction of the mean arterial pressure and also to the control plasma renin activity. Our study indicates that in most patients with cirrhosis, ascites and high plasma renin activity, arterial pressure is maintained by the effect of endogenous angiotensin II on the peripheral vasculature, and we suggest that a pre-existing arterial hypotension secondary to an arteriolar vasodilatation is the cause of renin release in these patients. Our results also show that angiotensin-II blockade is accompanied by a reduction of the post-sinusoidal hepatic vascular resistance.

Aldosterone↗
PubMed1981

Plasma renin activity and urinary sodium excretion as prognostic indicators in nonazotemic cirrhosis with ascites.

Azotemia is an ominous prognostic sign in cirrhosis with ascites. To investigate whether other renal disturbances are also prognostically significant, we studied the renin-aldosterone system and sodium excretion (UNaV) in 75 patients who had nonazotemic cirrhosis with ascites and related these to survival. On the basis of plasma renin activity patients were classified in two groups. Group I included 34 patients with normal renin activity (1.13 +/- 0.69 ng/mL . h) and Group II, 41 patients with high renin activity (7.46 +/- 3.86 ng/mL . h). The two groups differed significantly (p less than 0.001) in plasma aldosterone, UNaV, and wedged hepatic venous pressure but not in clinical features, liver function, glomerular filtration, and renal plasma flow. Patients of Group I lived significantly longer than those of Group II (the 50% survival rates were 28 months and 6 months, respectively). Survival curves obtained after grouping the patients according to UNaV (higher and lower than 10 meq/d) were almost identical to those obtained according to renin activity. The study results indicate that plasma renin activity and UNaV are of prognostic value in nonazotemic cirrhosis with ascites.

Adult↗
PubMed1980

Use of piretanide, a new loop diuretic, in cirrhosis with ascites: relationship between the diuretic response and the plasma aldosterone level.

Twenty patients with cirrhosis and ascites but no renal failure were given piretanide, a new loop diuretic, in order to investigate its efficacy and to relate the diuretic response with the pretreatment plasma aldosterone concentration. Eleven patients responded to piretanide 12 mg/day (equivalent in potency to 80 mg furosemide); there was no response in nine patients. Both groups were similar with regard to liver function, plasma urea, serum creatinine, plasma electrolytes, urine volume, and urine potassium concentration. The basal urinary sodium excretion was significantly higher in those patients who responded (23.6 +/- 5.7 mmol/day vs. 4.3 +/- 1.42 mmol/day; P < 0.01) (M +/- SE). Plasma renin activity (PRA) and plasma aldosterone concentration (PAC) were normal or only slightly increased in patients who responded to piretanide (PRA = 1.22 +/- 0.20 ng/ml/h; PAC = 12.25 +/- 2.20 ng/100 ml) and very high in patients who did not respond (PRA = 8.71 +/- 1.18 ng/ml/h; PAC = 84.6 +/- 16.2 ng/100 ml) (P < 0.001). Patients unresponsive to piretanide 12 mg/day also failed to respond when the dose was increased to 24 mg/day. However, the addition of spironolactone, 150 mg/day, to piretanide was followed in these patients by a marked increase in diuresis and natriuresis. These results strongly suggest that the pre-treatment level of aldosterone is an important factor influencing the response to loop diuretics in patients with non-azotaemic cirrhosis and ascites.

Adult↗
PubMed1979

[Treatment of the syndrome of inappropriate antidiuretic hormone secretion with demethylchlortetracycline (author's transl)].

A patient with a syndrome of inappropriate antidiuretic hormone secretion secondary to an undifferentiated bronchogenic carcinoma with distant metastases was treated with demethylchlortetracycline. Up until recently, treatment of this syndrome was based on water restriction and when the plasma sodium concentration became extremely low, hypertonic saline solution administration. Recently it has been demonstrated that the antibiotic demethylchlortetracycline inhibits the action of the antidiuretic hormone on the renal tubules. The drug has been used successfully in five patients with the syndrome of inappropriate antidiuretic hormone secretion. The administration of 900 mg of demethylchlortetracycline per day for 7 days in our patient produced an increase of free water clearance, diuresis, plasma sodium concentration, and plasma osmolarity. Urinary excretion of sodium and urinary osmolarity declined. Furthermore, the neurological symptoms attributed to hyponatremia improved markedly. The patient lost 6 kg during treatment, probably because of negative water balance induced by demethylchlortetracycline. Even though the administration of demethylchlortetracycline did not produce significant decreases in the glomerular filtration rate or renal blood flow in our patient, it is advisable to control the renal function in individuals treated with this drug since it may on occasion determine renal insufficiency.

Carcinoma, Bronchogenic↗
PubMed1979

Renal sodium retention in cirrhosis: relation to aldosterone and nephron site.

1. In a group of patients with cirrhosis who showed a wide range of values for the rate of renal sodium excretion, the latter was found to be inversely related to both the plasma concentration and rate of renal excretion of aldosterone. However, for a given sodium excretion the values for aldosterone were significantly lower in the patients than for a group of healthy control subjects. These findings suggest either an increased renal tubular sensitivity to aldosterone or the participation of other factors in the pathogenesis of the sodium retention. 2. Based on measurements of the rate of urine flow and the clearances of free water and inulin during a maximal water diuresis, the fractional reabsorption of sodium by the 'proximal', 'diluting segment' and 'distal' segments of the nephron was estimated. For patients retaining sodium the enhanced reabsorption occurred at both proximal and distal sites, the latter being quantitatively more important. There was no significantly enhanced sodium reabsorption in the diluting segment.

Aldosterone↗
PubMed1979

Renin, aldosterone and renal haemodynamics in cirrhosis with ascites.

The interrelationships between the renin-angiotensin-aldosterone system, renal haemodynamics and urinary sodium excretion were investigated in fifty-six non-azotaemic cirrhotics with ascites. In twelve additional patients the renal renin secretion rate was also studied. Plasma renin activity and concentration and plasma aldosterone ranged from normal to very high values. There was a significant inverse relationship between plasma aldosterone and the urinary sodium excretion. Plasma aldosterone showed a highly significant direct correlation with plasma renin activity, and plasma renin concentration was closely and directly related to the estimated renin secretion rate. Neither plasma renin activity, plasma renin concnetration nor the estimated renin secretion rate correlated with the renal plasma flow or the glomerular filtration rate. These results suggest that in non-azotaemic cirrhosis with ascites the renin-angiotensin-aldosterone system is an important factor influencing sodium excretion, increased plasma renin and aldosterone concentrations are mainly due to an increased secretion rate, and total renal perfusion is not a major factor influencing renin secretion.

Aldosterone↗