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  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Digestive diseases and sciences 36 (1991), S. 209-215 
    ISSN: 1573-2568
    Schlagwort(e): portal hypertensive rats ; portal-systemic shunting ; microspheres
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract In rats with partial portal vein ligation, 95±0.9% of the splenic blood flow is shunted from the portal to the systemic circulation when an intrasplenic injection of microspheres is used to determine the degree of shunting. Despite this magnitude of portal-systemic shunting, several biochemical and endocrine consequences of portal-systemic shunting occur at levels below what is expected for the degree of shunting found. In an effort to resolve these discordant findings, shunting from both the splenic and the mesenteric bed was studied in anesthetized portal hypertensive rats with various degrees and/or duration of portal vein stenosis. The shunting from the mesenteric bed averaged 66.7±29.9% (range 5.1–99.1%) and was influenced both by the degree and duration of portal vein stenosis. In contrast, shunting from the splenic bed averaged 97.3±4.0% (range 79–99.9%) and demonstrated no variation between groups determined by the degree of portal vein stenosis. The shunting from the splenic bed was consistently greater than that found from the mesenteric bed. Mesenteric but not splenic shunting correlated with serum bile acid levels. Mesenteric shunting was related inversely to the weight-adjusted liver mass and to serum testosterone levels. Based upon these data obtained in portal hypertensive rats, it is concluded that splenic injections of microspheres overestimate portal-systemic shunting. In contrast, mesenteric injections of microspheres yield values for shunting that correlate well with independently determined biochemical and endocrine consequences of shunting. These observations support the validity of the mesenteric shunting measurements obtained.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    The international journal of angiology 4 (1995), S. 31-33 
    ISSN: 1615-5939
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Propranolol is used for medical treatment of portal hypertension as it is believed to act as an indirect splanchnic vasoconstrictor via blockade of vasodilatory β2-receptors. However, a high proportion of nonresponders have been demonstrated in hemodynamic studies of the portal hypotensive effect of propranolol. The aim of the present study was to investigate the effect of various concentrations of propranolol on norepinephrine-induced pressor responses in isolated perfused mesenteric arteries of rats. Mesenteric arterial beds of six rats were perfused at a constant rate of 2 ml/minute with Krebs-Ringer solution at 37°C, and perfusion pressure was continuously recorded. Pressor responses to bolus injections of norepinephrine tended to increase in the presence of 10−6 M propranolol but were significantly attenuated in the presence of 10−5 M propranolol. In conclusion, a high concentration of propranolol paradoxically attenuates the pressor responses to norepinephrine in mesenteric arterial beds of rats. This is most likely explained by a nonspecific local anesthetic effect of propranolol.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    ISSN: 1573-2568
    Schlagwort(e): interferon-α2b ; chronic hepatitis C ; dose-response ; response rate
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Approximately 50% of patients with chronic hepatitis C respond to treatment with interferon-α. The aim of this randomized controlled trial was to evaluate whether an increase in dose of interferon-α augments response rate. One hundred thirty-eight patients with newly diagnosed chronic hepatitis C received a three-month course of 3 MU IFN-α2b administered every two days. All patients were anti-HCV and HCV-RNA (PCR) positive. Prior to treatment, a liver biopsy was performed. Complete response was defined by normal serum ALT concentrations and disappearance of HCV-RNA. After three months, 60 nonresponders were randomized (stratified according to histology) either to continue 3 MU interferon-α2b every two days for another six months (group A, total dose: 410 MU) or to receive increasing doses of interferon-α2b (6 MU every two days for three months, followed by 10 MU every two days for three months) (group B, total dose: 870 MU). Serum ALT concentrations were measured monthly and HCV-RNA at three-month intervals. Liver biopsy was repeated six months after end of treatment. Pretreatment characteristics of the randomized patients were: group A:N=30; male/female: 20/10; age: 54±10 years; CPH 9, CAH 8, cirrhosis 13; mean ALT 108±98 units/liter; group B:N=30; male/female: 21/9; age: 57±15 years; CPH 10, CAH 9, cirrhosis 11; mean ALT 90±40 units/liter. At the end of treatment six patients in group B but none in group A became responders [P=0.011 (Fisher's exact test), intent-to-treat analysis]. All six responders were noncirrhotics. High-dose interferon was not tolerated by six patients in group B. Noncompliance resulted in five dropouts in group A and one in group B. During the six-month follow-up, four of the six responders relapsed. A patient in group A with increased serum ALT concentration but negative HCV-RNA at the end of treatment became a full responder after six months. Of nonresponders to 3 MU interferon α2b every two days for three months, 20% responded to higher interferon doses, but none to continued standard dose. Prolonged treatment with interferon may be necessary to obtain a sustained response. However, treatment with higher-dose interferon was not tolerated in 20% of the patients.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Digestive diseases and sciences 39 (1994), S. 46-50 
    ISSN: 1573-2568
    Schlagwort(e): Kupffer cells ; portal hypertension ; portosystemic shunting ; reticuloendothelial system
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The increased incidence of infection in cirrhotics may in part be attributable to dysfunction of the reticuloendothelial system (RES) in removing pathogens from the circulation. The portosystemic shunting (PSS) that results from portal hypertension in cirrhotics may compromise RES function by allowing enteric pathogens to be shunted away from the Kupffer cells. A well-characterized model of portal hypertension induced by partial portal vein ligation (PVL), in which there is no hepatic parenchymal cell damage, was used. Kupffer cell function is unaltered and the effect of PSS alone on overall RES function can be evaluated. In addition to the usual immunologically inert [99mTc]sulfur colloid, an actual pathogen was also evaluated. PVL and sham-ligated rats were given either [99mTc]sulfur colloid orE. coli via the ileocolic vein. The right femurs, lungs, livers and spleens of the animals receiving99mTc were excised and the radioactivity counted. The lungs, livers, and spleens of the animals receivingE. coli were liquefied and the bacteria were quantified. For both groups the ratios of99mTc orE. coli in the lung, spleen, and femur to liver were calculated. PVL rats had significantly more99mTc in the lung, spleen, and femur than the sham rats. There were also significantly moreE. coli in the lungs for PVL rats but no significant difference in the spleen counts. These results imply that even in the absence of Kupffer cell dysfunction, PSS alters reticuloendothelial system function by causing a greater distribution of pathogens to the periphery. This altered distribution may contribute to an increased susceptibility to infection in cirrhotics.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 5
    ISSN: 1573-2568
    Schlagwort(e): ascites ; albumin ; cirrhosis ; portal hypertension
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Several studies performed in alcoholics with advanced liver disease have demonstrated a positive correlation between the serum-ascites albumin gradient (SAAG) and measured portal venous pressure. A single study performed in 15 patients with exudative malignant ascites and 29 patients with alcoholic liver disease demonstrated that a SAAG of 〈1.1 was essentially diagnostic of a malignant origin of the ascites. In an effort to confirm and extend these observations to individuals with nonalcoholic liver disease, 24 patients with nonalcoholic liver disease and 11 with alcoholic liver disease undergoing orthotopic liver transplantation (OTLx) were studied. At the time of liver transplantation, each had their serum and ascitic fluid albumin levels determined, the gradient calculated, and their portal venous pressure (PVP) as well as the corrected portal venous pressure (PPc) measured directly. A significant correlation (r=0.624) between the PPc and the SAAG was found in the 11 alcoholics (P〈0.05). No such correlation existed for those with nonalcoholic liver disease (r=0.398). Moreover, a SAAG 〈1.1 was found in three of nonalcoholics with cirrhosis in the absence of an abdominal malignancy. We conclude that (1) the SAAG and PPc are statistically related to each other in individuals with alcoholic liver disease but not in those with a nonalcoholic cause for cirrhosis, and (2) SAAG 〈1.1 is not diagnostic of abdominal malignancy but can occur in those with advanced nonmalignant hepatic disease.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Digestive diseases and sciences 36 (1991), S. 1309-1312 
    ISSN: 1573-2568
    Schlagwort(e): hepatic regeneration ; age ; hormone status ; prolactin ; cyclosporine
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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