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Biomedical subjects

C Merkel

Publications and source records attributed to C Merkel.

At least 91 records · Page 5Linked to original sources
PubMed1986

Effect of nadolol on liver haemodynamics and function in patients with cirrhosis.

Beta-adrenoceptor blockers used in the medical management of portal hypertension decrease liver blood flow. The sporadic onset of hepatic encephalopathy during propranolol treatment was ascribed to this decrease. The aim of the present study was to evaluate the effect of chronic treatment with nadolol on liver blood flow and liver function. Nadolol, a non-cardioselective beta-adrenoceptor blocker, has been reported to be as powerful as propranolol in decreasing portal pressure. Before and after 1 month of treatment with nadolol at a dose reducing heart rate by 25%, in 15 cirrhotic patients with portal hypertension, the following parameters were determined: hepatic venous pressure gradient, hepatic blood flow, galactose eliminating capacity, aminopyrine metabolic activity, ICG clearance and intrinsic hepatic clearance. Hepatic venous pressure gradient and hepatic blood flow were decreased by nadolol. However liver function was not affected by the drug. We conclude that, despite a lowered hepatic blood flow, liver function is not affected by 1 month of nadolol treatment.

Adult↗
PubMed1985

Blood flow of experimental liver metastases in rat as evaluated by the locally injected 133-Xenon washout.

The investigations on blood flow in liver metastases are interesting from both a pathophysiological and a therapeutic point of view. Available data, however, are few and not definitive, as these studies are complex and difficult to perform. In a group of 25 Sprague-Dawley rats, in which liver metastases of Walker-256 carcinoma had been implanted, the blood flows in a metastasis and in the normal liver surrounding it were determined by means of the locally injected 133-Xenon washout. Thirteen sham-operated rats were a control group. Blood flow in the metastases was decreased as a group compared to that in the normal liver surrounding metastases and to that in liver of sham-operated rats. Small metastases showed normal or increased blood flow, large ones decreased or stagnant blood flow. Moreover, a significant inverse correlation was found between blood flow and diameter of metastasis. It is concluded that liver metastases of Walker-256 carcinoma show a decrease in blood flow which is related to the size of metastasis.

Animals↗
PubMed1985

Renal water and sodium handling in compensated liver cirrhosis: mechanism of the impaired natriuresis after saline loading.

The present study was attempted to evaluate sodium and water balance in compensated liver cirrhosis. Renal sodium and water handling was studied in six cirrhotic patients without ascites and/or oedema and in six controls before and after saline loading. Fractional sodium reabsorption at the various nephron sites (proximal, diluting and distal) was evaluated by means of clearance techniques during maximal water diuresis and hypotonic saline infusion. Compensated cirrhotic patients showed a normal baseline sodium and water balance but a blunted natriuretic response when saline loaded (urinary sodium excretion after saline load = 338 +/- 290 compared to 933 +/- 504 mumol min-1 of controls; P less than 0.05). The impaired natriuresis was found to be related to an increased reabsorption of sodium in the proximal tubule (proximal fractional sodium reabsorption = 88.4 +/- 3.8 compared to 81.7 +/- 4.3% of controls; P less than 0.05). These findings confirm the hypothesis that renal sodium handling abnormalities might precede ascites formation. Additional studies, however, are necessary to further define renal factors mediating the increased reabsorption of sodium in compensated liver cirrhosis.

Adult↗
PubMed1985

Splenic haemodynamics and portal hypertension in patients with liver cirrhosis and spleen enlargement.

The relationships between portal hypertension and spleen enlargement, in patients with liver cirrhosis, are not clearly defined; as well as those between splenic haemodynamics and portal hypertension. In 25 cirrhotics with spleen enlargement and portal hypertension and in seven controls, the following parameters were determined: estimated splenic volume (ESV) from the radiographic view of the spleen, according to Blendis, Williams and Kreel (1969), specific splenic blood-flow (SSBF), total splenic blood-flow (TSBF), porto-hepatic gradient (PHG), specific splenic resistance (SSR) and total splenic resistance (TSR). Moreover, the size and extension of oesophageal varices, at oesophagoscopy, were classified according to Dagradi (1973). PHG, ESV and TSBF were increased in all subjects, SSBF was increased in two cases, SSR was increased in two cases and decreased in two cases, TSR was decreased in all cases and ESV was not correlated to the level of portal hypertension. Neither TSBF nor TSR were found to be correlated to the level of portal hypertension, as estimated by PHG or by oesophageal varices. It is concluded that, in patients with liver cirrhosis and spleen enlargement, splenomegaly is likely to be the consequence of pulp hyperplasia and not of passive congestion, and that increases in splenic blood-flow do not contribute significantly to portal hypertension.

Adult↗
PubMed1985

Effect of somatostatin on splanchnic hemodynamics in patients with liver cirrhosis and portal hypertension.

The effect of somatostatin on splanchnic hemodynamics in patients with liver cirrhosis is not clearly defined, as some authors report a decrease in portal pressure and in liver blood flow during intravenous administration of this hormone, while others do not. In 19 subjects with liver cirrhosis and portal hypertension the following parameters were measured before and during intravenous administration of somatostatin (7.5 micrograms/min): porto-hepatic gradient, estimated hepatic blood flow, specific splenic blood flow, cardiac index. Estimated hepatic blood flow decreased significantly during somatostatin infusion (p less than 0.05), averaging a 13% decrease; porto-hepatic gradient, splenic specific blood flow and cardiac index did not vary significantly. These data indicate that somatostatin infused at a dose of 7.5 micrograms/min induces a slight decrease in liver blood flow without affecting portal hypertension.

Adult↗
PubMed1985

Use of a nonselective beta-blocker, nadolol, in the treatment of portal hypertension in cirrhotics.

Recently a medical treatment with propranolol has been proposed in order to decrease portal pressure and lessen the risk of recurrent gastrointestinal bleeding in cirrhotic patients. No data are available about another beta-blocker, nadolol, which, unlike propranolol, has a low hepatic metabolism, a low lipid solubility, a long serum half-life and does not reduce renal blood flow in patients with arterial hypertension. In 18 cirrhotics with portal hypertension, the effects of nadolol were studied on systemic and hepatic haemodynamics and liver function, at a dosage which reduced the heart rate by 25%. After one month of treatment, a significant decrease in cardiac output, portohepatic gradient and estimated hepatic blood flow were found. The degree of oesophageal varices was reduced in 11 patients, unchanged in the other seven. Hepatic function, evaluated by galactose eliminating capacity, did not change significantly. Although the small number of treated patients does not allow definitive conclusions, nadolol seems to have the features needed to be used in the medical treatment of portal hypertension in patients with liver cirrhosis.

Cardiac Output↗
PubMed1984

[Effect of somatostatin on splanchnic hemodynamics in liver cirrhosis].

The effect of somatostatin on splanchnic haemodynamics in patients with liver cirrhosis is not clearly defined, as some Authors reported a decrease in portal pressure and in liver blood flow during i.v. administration of this hormone, while others did not. In 19 subjects with liver cirrhosis and portal hypertension the following parameters were measured before and during i.v. infusion of somatostatin (7.5 micrograms/min): porto-hepatic gradient, effective hepatic plasma flow, specific splenic blood flow, cardiac output. Moreover the gastrin-G-17 plasma levels, those of insulin and growth hormone were measured. Effective hepatic plasma flow decreased significantly during somatostatin infusion (P less than 0.05), averaging a 15% decrease. Porto-hepatic gradient, specific splenic blood flow, cardiac output did not vary significantly. Gastrin, insulin and growth hormone plasma levels decreased significantly (P less than 0.02, 0.01, 0.05). These data indicate that somatostatin infused at the dose of 7.5 micrograms/min provokes endocrine effects, but as far as the splanchnic circulation is concerned, it induces a slight decrease in liver blood flow without affecting portal hypertension.

Adult↗
PubMed1984

Effects of nadolol treatment on renal and hepatic hemodynamics and function in cirrhotic patients with portal hypertension.

Twelve cirrhotic patients with portal hypertension and esophageal varices were treated with nadolol for 1 month, and the effects on renal and hepatic hemodynamics and function were studied. A significant decrease in cardiac output, portohepatic gradient, and effective hepatic blood flow was found, whereas mean arterial pressure, liver function, effective renal blood flow, glomerular filtration rate, and urinary sodium and potassium excretions were not affected. In seven patients esophageal varices were also reduced. A significant correlation was found between the decrease in portohepatic gradient and that in cardiac output. The percentage of cardiac output distributed to the kidneys was significantly increased after nadolol treatment. In conclusion, nadolol seems to have properties useful for the treatment of portal hypertension in patients with liver cirrhosis.

Adrenergic beta-Antagonists↗
PubMed1984

Carbohydrate and lipid metabolism in cirrhosis. Evidence that hepatic uptake of gluconeogenic precursors and of free fatty acids depends on effective hepatic flow.

Splanchnic arteriovenous differences for several intermediary metabolites of carbohydrate and lipid metabolism were determined simultaneously with hepatic blood flow in seven normal subjects, eight patients with cirrhosis, and six patients with cirrhosis after surgical portosystemic shunt ( SPSS ) after an overnight fast. Arteriovenous differences in the legs were also determined together with flux measurement. The individual turnover rates of acetoacetate (AcAc) and 3 hydroxybutyrate (beta OHB) were also determined by means of isotopic techniques. Splanchnic gluconeogenic precursors and FFA uptakes were lower in cirrhotic patients with SPSS than in normal subjects (P less than 0.05 and P less than 0.01, respectively). Splanchnic triglyceride output was also lower in cirrhotic patients with SPSS than in normal subjects (P less than 0.01), whereas no significant differences were found for AcAc, beta OHB, and glucose release. In the group of cirrhotic patients without SPSS , those patients with negligible signs of portal systemic shunt and normal splanchnic blood flow had uptake of gluconeogenic precursors and of FFA normal or higher than that of normal subjects, whereas those patients with signs of spontaneous portal systemic shunt behaved like cirrhotic patients with SPSS . Alanine release from the leg was lower in both cirrhotic patient groups. Tracer determined hepatic output of AcAc and beta OHB was higher in cirrhotic patients with SPSS (P less than 0.05). Plasma clearance rates of AcAc and beta OHB were significantly elevated in both cirrhotic patient groups. Close agreement was found between tracer and catheterization techniques in the evaluation of ketone body production in cirrhotic patients with SPSS , whereas in cirrhotic patients without SPSS tracer determined hepatic output was slightly lower, possibly because of extrahepatic splanchnic tissue ketone body uptake. In conclusion, our data in patients with cirrhosis indicate that: 1) splanchnic uptake of gluconeogenic precursors and of FFA was related to the degree of portal systemic shunt, e.g. to the degree of effective hepatic blood flow; 2) liver triglyceride but not ketone body output was decreased by the impaired FFA (and glycerol) liver uptake; 3) the higher circulating levels of gluconeogenic precursors (except alanine) and of FFA appeared at least partially due to lower hepatic removal of these metabolites; and 4) peripheral use of ketone bodies was increased and alanine release from the leg reduced in patients with cirrhosis.

Adult↗
PubMed1983

Renal effects of aminophylline in hepatic cirrhosis.

In 18 cirrhotics with impaired renal perfusion intravenous injection of aminophylline 3 mg/kg b.w. increased mean renal blood flow (133-Xenon washout) from 1.77 +/- 0.71 to 1.99 +/- 0.44 ml/g/min (p less than 0.01). No significant change in cardiac output was found. In a further 10 cirrhotic patients the administration of aminophylline 3 mg/kg decreased the mean tubular reabsorption of sodium in the proximal section of the nephron (distal delivery) from 10.5 +/- 6.2 to 16.3 +/- 16.5 (p less than 0.01). Free-water production increased as a consequence of the increased supply of sodium to the diluting segment. Thus, aminophylline acts favourably on the functional renal impairment that occurs in hepatic cirrhosis.

Adult↗
PubMed1983

Relationship between plasma levels of factor VIII related antigen and reticulo-endothelial function in chronic uremia.

The plasma levels of factor VIII related antigen (F VIIIR:Ag; determined by rocket electrophoresis) and reticulo-endothelial function (measured by means of the removal kinetics of human albumin millimicrospheres) were studied in a group of patients with chronic renal failure. F VIIIR:Ag plasma levels were increased, median 304% (interquartile ranges 211-443%) compared to the controls, median 112% (interquartile ranges 100-144%); P less than 0.01. Reticulo-endothelial function was decreased, median 8.3 micrograms/min/kg body wt (interquartile ranges 6.2-10.1 micrograms/min/kg body wt) compared to the controls, median 15.0 micrograms/min/kg body wt (interquartile ranges 11.9-19.0 micrograms/min/kg body wt); P less than 0.02. A significant inverse relationship was found between plasma levels of F VIIIR:Ag and the reticulo-endothelial function rs = 0.075; P less than 0.01). As the main site of catabolism of F VIIIR:Ag is the reticulo-endothelial system, the impairment of its function appears to be a possible explanation for the elevated plasma levels of the F VIIIR:Ag found in patients with end stage renal disease.

Adult↗
PubMed1982

Proteinuria in patients with cirrhosis: relationship between renal and hepatic function.

1. In 37 patients with cirrhosis of the liver of different severity (11 in class A, 18 in class B, and 8 in class C, according to Child's criteria modified by Hobbs), inulin and p-aminohippurate clearances, total fractional protein excretion and the fractional clearances of alpha 1-acid glycoprotein, albumin, transferrin, alpha 2-macroglobulin and beta 2-microglobulin (in 20 patients) were determined. 2. Insulin clearance was lower than 70 ml/min in 19 patients had p-aminohippurate clearance was lower than 300 ml/min in 20 patients. Total fractional protein excretion was above normal in 19 patients; alpha 1-acid glycoprotein fractional clearance was above normal in 11, albumin fractional clearance in 10, transferrin fractional clearance in five, alpha 2-macroglobulin fractional clearance in three, and beta 2-microglobulin fractional clearance in 10. 3. The increases in protein excretion were independent of any impairment of renal tubular function. An inverse relationship between protein excretion and the clearances of inulin and p-aminohippurate was found. No difference in protein excretion was found between the three groups of patients with different degrees of liver damage. 4. The results suggest that in cirrhosis an increase in glomerular permeability is frequent, though generally slight; it is correlated with an impairment of kidney function and is independent of the severity of the liver damage.

Adult↗
PubMed1982

Lack of correlation between endotoxaemia and renal hypoperfusion in cirrhotics without overt renal failure.

Renal involvement in patients with liver cirrhosis is characterized by renal vasoconstriction, the aetiology of which remains obscure. Endotoxaemia, frequently found in patients with liver cirrhosis and renal failure, has been emphasized as a pathogenic factor. In fifty-seven patients with liver cirrhosis without overt renal failure endotoxin plasma level (Limulus Lysate test), mean renal blood flow (MRBF) (133Xe washout technique), and effective renal plasma flow (ERPF) (p-aminohippurate clearance) were determined. MRBF was decreased in nineteen out of twenty-seven patients, averaging 1.88 +/- 0.51 ml g-1 min-1 (in fourteen controls 3.17 +/- 0.51 ml g-1 ml-1). ERPF was decreased in seventeen out of thirty patients, averaging 380 +/- 164 ml/min (in eighteen controls 624 +/- 127 ml/min). Systemic endotoxaemia was found in sixteen out of fifty-seven patients, levels ranging from 0.62 to 200 ng/ml. No significant difference in renal blood flow values was found between patients with and without endotoxaemia (MRBF = 1.78 +/- 0.51 and 1.93 +/- 0.52 ml g-1 min-1 respectively; ERPF = 429 +/- 119 and 365 +/- 175 ml/min respectively). No significant difference in the frequency of endotoxaemia was found between patients with impaired and unimpaired renal blood flow. Moreover no relation was found between endotoxin plasma levels and MRBF and ERPF respectively. In conclusion in patients with cirrhosis without overt renal failure renal vasoconstriction does not seem to be related to endotoxaemia.

Adult↗
PubMed1982

Enhanced renal sympathetic tone in liver cirrhosis: evaluation by intrarenal administration of dihydroergocristine.

Mean renal blood flow (MRBF), cortical blood flow (CBF), glomerular filtration rate (GFR), heart rate, arterial blood pressure, Na+ and K+ excretion were determined before and 10 min after intrarenal administration of dihydroergocristine (0.017 mg/kg b.w.) in 13 patients suffering from liver cirrhosis. Cardiac output was also determined in 6 patients. Baseline values of MRBF and CBF were significantly lower in cirrhotics than in the 14 control subjects. Following intrarenal administration of the drug, renal hemodynamic parameters increased significantly, while GFR decreased. Systemic hemodynamic parameters, diuresis, Na+ and K+ excretions were unchanged. These data show that dihydroergocristine has a renal vasodilator effect, probably mediated by alpha-adrenergic blockade. The effect probably is prevalent at the postglomerular site, where the increase in vascular resistance is greatest. The effect of the drug suggests that patients with liver cirrhosis have enhanced renal sympathetic activity which is, at least in part, responsible for the renal vasoconstriction.

Adult↗
PubMed1982

Renal haemodynamic in essential hypertension assessed by 133-Xenon washout and selective renal angiography.

The renal and intrarenal haemodynamic pattern in 17 patients with essential hypertension of different severity and duration was studied by means of the 133-Xenon washout technique and the selective renal angiography. The mean and the cortical renal blood flows were on average significantly decreased as compared to the controls. A good agreement was found between the reduction in renal perfusion and the degree of vascular abnormalities as shown by angiography; on the contrary no correlation was found between the impairment in renal blood flow and the degree and/or duration of hypertension.

Adult↗