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Biomedical subjects

A Gatta

Publications and source records attributed to A Gatta.

At least 127 records · Page 7Linked to original sources
PubMed1988

Hemodynamic changes of systemic, hepatic, and splenic circulation following triglycyl-lysin-vasopressin administration in alcoholic cirrhosis.

Triglycyl-lysin-vasopressin is a long-acting vasopressin derivative which is under consideration for the treatment of acute variceal bleeding in cirrhosis. However, its splanchnic hemodynamic effects have not been investigated thoroughly. In 11 patients with alcoholic cirrhosis, systemic and splanchnic hemodynamics were evaluated before and 20-40 min after intravenous administration of 2 mg triglycyl-lysin-vasopressin. Following the drug administration, heart rate decreased by 10% and cardiac index by 22% on the average, respectively; mean arterial pressure increased by 14% and systemic vascular resistence index by 48%. Hepatic venous pressure gradient showed a marked and persistent fall, averaging 31%. Hepatic and splenic blood flow decreased by 31% and 56%, respectively. A significant correlation was found between the decrease in hepatic venous pressure gradient and in splenic blood flow. By contrast, the decrease in the hepatic venous pressure gradient was not significantly correlated to the decrease in hepatic blood flow or in cardiac index. We conclude that in patients with alcoholic cirrhosis, triglycyl-lysin-vasopressin decreases portal pressure as well as hepatic and splenic blood flows. The decrease in portal pressure was due to the decrease in splanchnic blood inflow and not to the decrease in cardiac index.

Adult↗
PubMed1988

Effects of iloprost, a prostacyclin analog derivative, on renal plasma flow, renal function, and renin-aldosterone system in humans.

The effects of iloprost, a stable analog derivative of prostacyclin, on heart rate, blood pressure, renal plasma flow (RPF), glomerular filtration rate, filtration fraction, urine flow, fractional excretion of sodium (FENa), proximal fractional sodium reabsorption (PFRNa), fractional sodium resorption at the ascending limb of Henle's loop (HFRNa), plasma renin activity (PRA), and plasma aldosterone concentration (PA) were evaluated in patients with peripheral vascular disease and normal renal function. In 10 patients the drug was administered intravenously for 6 hours daily for 6 days at a rate of 1 ng/kg/min. In 7 patients iloprost was also administered at a dose of 2 ng/kg/min for the same time. There was no significant change in heart rate and blood pressure at both iloprost doses. At the dose of 1 ng/kg/min the drug had no effect on renal hemodynamics and function, PRA, and PA. At the dose of 2 ng/kg/min iloprost significantly increased RPF (p less than 0.025) and FENa (p less than 0.025) and significantly decreased HFRNa (p less than 0.025) without affecting glomerular filtration rate, filtration fraction, urine flow, PFRNa, PRA, and PA. No correlation was found between the increase in RPF and FENa (r = 0.01). We conclude that at a dose of 2 ng/kg/min, but not 1 ng/kg/min, iloprost has a natriuretic effect secondary to inhibition of sodium reabsorption at the ascending limb of the Henle's loop and not related to the renal hemodynamic effect.

Aged↗
PubMed1988

The calcium-channel blocker, verapamil, does not improve portal pressure in patients with alcoholic cirrhosis.

1. Recently the calcium-channel blocker, verapamil, has been reported to decrease portal pressure in rats with experimental cirrhosis and in patients with liver cirrhosis. 2. In eight patients with alcoholic cirrhosis the effect of verapamil (5 mg i.v.) on systemic and splanchnic haemodynamics was investigated. 3. Mean arterial pressure, wedged hepatic venous pressure, hepatic venous pressure gradient, and verapamil plasma concentrations were measured before and at 10, 20, 30 min following 5 mg i.v. administration of verapamil. At 30-40 min cardiac output, systemic vascular resistance and hepatic blood flow were also measured. 4. Verapamil plasma concentrations averaged 47.9 +/- 52.0, 36.5 +/- 36.3, 31.3 +/- 33.9 ng ml-1 at 10, 20, 30 min respectively: mean arterial pressure and systemic vascular resistance decreased significantly (-9% and -14% respectively), and cardiac index increased significantly (+8%). Wedged hepatic venous pressure and hepatic venous pressure gradient remained unchanged, variations never exceeding 0.2 kPa. Hepatic blood flow increased significantly by 12%. 5. These results show that i.v. administration of 5 mg verapamil does not decrease portal pressure in alcoholic cirrhosis. This lack of effect is probably the consequence of a balance between decrease in porto-hepatic vascular resistance and increase in splanchnic blood inflow.

Adult↗
PubMed1988

Impaired renal water excretion in liver cirrhosis. The role of reduced distal delivery of sodium.

The study was aimed to assess the relationships between distal sodium delivery and renal diluting ability in liver cirrhosis. Renal response to maximal water load was evaluated in 18 cirrhotic patients without ascites, 12 with mild or moderate ascites, and 26 controls. Distal sodium delivery was derived from clearance calculations during the hypotonic diuresis induced by maximal water load. Although ascitic patients showed a greater impairment in free-water excretion, the pattern of the renal response to maximal water load was similar in ascitic and non-ascitic patients; it was characterized by reduced free-water clearance and reduced distal delivery of sodium. Free-water clearance corrected for distal sodium delivery was normal in non-ascitic patients and in the majority (75%) of decompensated cirrhotics, indicating a primary role of an increased proximal sodium resorption in the pathogenesis of the impaired water excretion of these patients. Renal diluting capacity did not correlate with the severity of liver functional impairment, as evaluated by single liver function tests or by Child's criteria.

Adult↗
PubMed1988

[Liver metabolism of indocyanine green and aminopyrine in liver cirrhosis: relations with functioning liver cell mass].

Hepatic clearance of indocyanine green, a drug with a high hepatic extraction rate, and breath tests with aminopyrine, a drug with a low hepatic extraction ratio, were calculated in 26 patients with liver cirrhosis. In addition galactose elimination capacity was calculated as an index of functional liver cell mass. All these parameters resulted significantly correlated with each other. These results confirm the view that during liver cirrhosis, metabolism of drugs with high and low hepatic extraction rates can be described according to the intact hepatocyte theory.

Adult↗
PubMed1988

Verapamil pharmacokinetics and liver function in patients with cirrhosis.

In seven patients with liver cirrhosis, verapamil plasma levels were measured in blood drawn simultaneously from the hepatic vein and from an artery during the post-distributive phase after an intravenous bolus infusion of 5 mg of verapamil. In addition the hepatic plasma flow was measured using the indocyanine-green constant infusion technique. From these data the verapamil hepatic clearance and verapamil intrinsic clearance were calculated. The verapamil hepatic clearance was 423 +/- 92 ml/m, the hepatic plasma flow was 819 +/- 318 ml/m, and the verapamil intrinsic clearance was 1431 +/- 961 ml/m. As compared to values reported in the literature, a decrease of the verapamil hepatic clearance by 50% approximately was found, while the hepatic plasma flow was in the normal range and the verapamil intrinsic clearance was reduced by 75%. These data show that in patients with cirrhosis the decrease in verapamil clearance is due to an impairment in the capacity of the liver to remove the drug, and not to a decrease in liver perfusion.

Adult↗
PubMed1987

The use of human albumin millimicrospheres tagged with 99mTc in the evaluation of the removal capacity of the reticuloendothelial system.

Liver uptake kinetics of 99mTc labelled millimicrospheres of human serum albumin (MM) was studied in 16 subjects. Every subject received four doses of MM intravenously. The uptake constant decreased progressively with increasing dose. The maximum liver removal capacity, a parameter which is independent of liver blood flow, was calculated according to the method of Iio and Wagner (1963). From these data we conclude that MM are taken up by the reticuloendothelial system (RES) with saturable kinetics, and they are suitable for clinical use to evaluate RES function in man.

Adult↗
PubMed1987

Renal effects of nadolol in cirrhosis.

The effects of nadolol on renal haemodynamics and function, and on the renin-angiotensin-aldosterone system and on renal prostaglandin production were studied in eighteen cirrhotics. After 1 month of treatment, nadolol had significantly decreased cardiac output by 25% without affecting arterial pressure, renal plasma flow or renal vascular resistance. Glomerular filtration rate, filtration fraction and the proportion of the cardiac output delivered to the kidneys were significantly increased. The renin-angiotensin-aldosterone system was suppressed and urinary PGE2 excretion was slightly increased. The latter effects were not correlated with those on renal haemodynamics and function.

Cardiac Output↗
PubMed1987

Effects of isosorbide dinitrate on portal hypertension in alcoholic cirrhosis.

It has recently been reported that vasodilators lower portal pressure in patients with cirrhosis. This effect, however, is not definitively proven. The effect of isosorbide dinitrate (5 mg sublingually) on splanchnic and systemic hemodynamics was investigated in 13 patients with alcoholic cirrhosis and portal hypertension. The administration of isosorbide dinitrate reduced hepatic venous pressure gradient by 34% (P less than 0.001), mean arterial pressure by 30% (P less than 0.001), cardiac index by 17% (P less than 0.001) and systemic vascular resistance by 11% (P = 0.05). Hepatic blood flow was not affected by the treatment. Significant correlations were found between the decrease in hepatic venous pressure gradient and that of cardiac index (P less than 0.05) and mean arterial pressure (P less than 0.05). These data indicate that isosorbide dinitrate lowers portal pressure in patients with cirrhosis. Decrease in cardiac output, rise in splanchnic arterial vascular resistance and decrease in porto-hepatic resistance seem to participate in determining the effect.

Adult↗
PubMed1987

Long-term effects of beta-adrenergic blockade with nadolol on hepatic and renal haemodynamics and function in cirrhotics.

Non-cardioselective beta-blockers are used for prevention of re-bleeding from oesophageal varices in cirrhotics with portal hypertension. Nadolol, a non-cardioselective beta-blocker with a low liposolubility and a low hepatic metabolism, has been demonstrated to decrease portal pressure in cirrhotic patients. Since cirrhotics need long-term treatment, we investigated long-term effects of beta-adrenergic blockade with nadolol on hepatic and renal haemodynamics and function in a group of patients with cirrhosis and portal hypertension. In 19 patients with cirrhosis, after one and six months of treatment with nadolol hepatic venous pressure gradient showed a significant and persistent decrease, averaging 19% and 22%, respectively. Hepatic function and renal haemodynamics and function remained unaffected. Oesophageal varices severity was lowered in 11/19 patients after one month, in 9/16 after six months, in 8/14 after 12 months and in 5/10 after 18 months. Our results showed that, also after long-term treatment, nadolol decreases portal pressure and, in approximately 50% of patients, oesophageal varices severity, without side-effects on liver and renal function.

Adult↗
PubMed1987

Does defective chloride reabsorption at the loop of Henle play a major role in the pathogenesis of Bartter's syndrome?

In a patient with typical features of Bartter's syndrome, intrarenal reabsorption of sodium and water at different sites of the nephron, during maximal water diuresis, was studied twice in the course of the disease. During the first study, chloride reabsorption at the loop of Henle and renal diluting ability were not impaired. Chloride reabsorption at the loop of Henle was 0.72 (normal values 0.66-0.90), minimal urine osmolality 71 mosm/kg (normal values less than 75 mosm/kg) and chloride fractional clearance 0.44 (normal values 0.3-6.8). An impaired chloride reabsorption at the loop of Henle was found 6 months later. Chloride reabsorption at the loop of Henle was 0.28, minimal urine osmolality 197 mosm/kg and chloride fractional clearance 8.23. These data suggest that the defect in chloride reabsorption at the loop of Henle is not a pathophysiological abnormality of the syndrome because it appeared at a later time than the other symptoms.

Absorption↗
PubMed1987

Value of prealbumin plasma levels as liver test.

To assess the sensitivity, specificity and clinical value of prealbumin as liver test, prealbumin plasma levels were measured in 100 patients with liver disease and in 65 patients without clinical evidence of liver impairment. The sensitivity of prealbuminemia was higher than that of albumin, pseudocholinesterase, apolipoprotein and prothrombin activity. Its specificity was higher than that of pseudocholinesterase and comparable with the specificity of other liver tests. Prealbumin plasma levels were progressively decreasing in patients with liver cirrhosis graded as Child's A, B and C, respectively. In these patients prealbuminemia was correlated with galactose elimination capacity, assumed to be an index of maximal liver functional capacity.

Adolescent↗
PubMed1987

Nadolol for prevention of variceal rebleeding in cirrhosis: a controlled clinical trial.

Nadolol, a nonselective beta-blocker, has been shown to decrease portal pressure in patients with cirrhosis at the same degree as propranolol. No data are available, however, about its effect on rebleeding rate and mortality in patients undergoing prevention of rebleeding from esophageal varices. A prospective randomized clinical trial was performed in patients with cirrhosis who survived a documented episode of variceal hemorrhage. 12 patients received nadolol, 12 placebo. Patients with child's C grade, tense ascites, renal failure, contraindications to beta-blocker, or age greater than 70 were not included. After a follow-up of up to 145 weeks, 9 patients in the nadolol group and 4 in the placebo group survived free from rebleeding (log-rank test: chi 2 = 4.35, p less than 0.05). Survival was not statistically different in the two groups (1 death in the nadolol group, 3 in the placebo group). In conclusion, nadolol appears to represent an effective therapy in the prevention of variceal rebleeding in cirrhotic patients.

Adult↗
PubMed1987

Effect of somatostatin on liver blood flow and liver metabolic activity in patients with cirrhosis.

In a group of 10 patients with cirrhosis, protal hypertension, and previous gastro-intestinal bleedings, hepatic plasma flow, indocyanine green clearance and intrinsic hepatic clearance were determined before and during i.v. infusion of somatostatin (7.5 micrograms/min). The same study protocol was performed in a further seven patients with cirrhosis infused with placebo. All these parameters were significantly decreased by the drug (p less than 0.05; less than 0.01; less than 0.01, respectively) mean decrease being 12, 9 and 8%, respectively, while no significant change occurred in the placebo-infused patients. These data indicate that somatostatin infused at a dose of 7.5 micrograms/min in cirrhotics provokes a slight decrease in hepatic plasma flow and in liver metabolic activity. This effect may contribute to further decrease hepatic removal of harmful substances and may increase systemic concentration of drugs metabolized by the liver.

Adult↗
PubMed1987

Tubular handling of sodium and phosphate in non-ascitic liver cirrhosis.

The renal response to a maximal water load was evaluated in eight cirrhotic patients free of ascites and without previous evidence of ascites and in seven controls. Fractional sodium reabsorption in the proximal and diluting segment was estimated by clearance methods during hypotonic diuresis. Since phosphate excretion has been proposed as a proximal marker in liver cirrhosis, sodium reabsorption in the proximal tubule was compared with phosphate fractional excretion. In spite of a normal sodium balance during the pre-study period, non-ascitic cirrhotics showed a blunted proximal natriuretic response to maximal water load. In fact sodium excretion during hypotonic diuresis was reduced (p less than 0.05) and proximal sodium reabsorption increased (p less than 0.005) in cirrhotics. Fractional phosphate excretion was not impaired in our patients, and no correlation was found between phosphate excretion and proximal sodium reabsorption, as evaluated by clearance methods. This study demonstrates that an increased reabsorption of sodium in the proximal tubule is responsible for the impaired response to maximal water load in non-ascitic cirrhotics. Abnormalities in tubular handling of phosphate may account for the dissociation between proximal sodium reabsorption and phosphate excretion during hypotonic diuresis in these patients.

Adult↗
PubMed1986

Redistribution of renal blood flow in patients with liver cirrhosis. The role of renal PGE2.

Cirrhotic patients frequently show a decrease in renal blood flow and redistribution of the flow from the outer cortex to the juxtamedullary cortex. The cause of the maintenance of juxtamedullary perfusion is not presently known. Prostaglandin E2 (PGE2) has its vasodilating effect on medullary and juxtamedullary vessels where it is synthesized. Therefore, its increased production, frequently shown in cirrhotics, could be responsible for the relative preservation of juxtamedullary blood flow. To verify this hypothesis we examined 13 cirrhotic patients. In these patients we determined mean renal blood flow (MRBF), blood flow in the 1st compartment (ICBF) and in the 2nd compartment (IICBF) with the 133-Xenon washout technique and PGE2 plasma levels in the renal veins (PGE2V). MRBF and ICBF were significantly reduced as compared to control subjects (P less than 0.01); IICBF resulted unaltered. Significant correlation was found between IICBF and PGE2V (P less than 0.01). Our data confirm the decrease in renal blood flow and the redistribution of intrarenal blood flow in cirrhotic patients. The maintenance of IICBF is likely to be a consequence of PGE2 renal production.

Adult↗