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Query: UMLS:C0008370 (cholestasis)
 9,378 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Recent results regarding the pathophysiology of hyperlipoproteinemia in cholestasis are reported. The isolation of an abnormal lipoprotein (Lipoprotein-X; LP-X) from the plasma of cholestatic patients was achieved by a combination of various physico-chemical techniques. Most of the plasmacholesterol in these patients is transported in form of this abnormal lipoprotein which is very rich in phospholipids and unesterfied cholesterol. LP-X represents a vesicle with a mean diameter of 700 A. Albumin takes part as a structural protein of the particle. Besides albumin, which seems to be located in an internal water compartment or to be covered with lipids. Apo-C and Apo-D are present as surface proteins. The lack of Apo-B in LP-X, the major apoprotein of normal low density lipoproteins, seems to be the reason for a disturbed endogenous feedback mechanism of hepatic cholesterol synthesis, which is strongly increased in cholestasis. The high specificity and power of the LP-X test as clinical-chemical parameter to demonstrate or exclude cholestasis finds its explanation in our knowledge about the origin of this abnormal lipoprotein in cholestasis. LP-X is formed when a lipoprotein normally excreted with the bile refluxes into the plasma stream to convert into LP-X. This formation depends only on certain physico-chemical requirements and is independent of an energy-providing or enzymatically regulated process. The biological halflife of LP-X is similar to that of normal plasmalipoproteins. However, enzymes of postheparin plasma as well as the lecithin: cholesterol acyltransferase do not seem to play a major role in the catabolism of lipoprotein-X, but only change some of the physicochemical characteristics of this vesicle.
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PMID:[Studies on the structure and metabolism of lipoprotein-X (LP-X), the abnormal plasmalipoprotein in cholestasis (author's transl)]. 19 98

Bile flow and excretion of monohydroxy-, dihydroxy- and trihydroxy-bile acids (MBA, DBA and TBA) were estimated after acute and subacute phenobarbital and chlorpromazine pretreatment in 60-day-old male Wistar rats. Bile was collected in bile-fistula rats in three 1-hour periods. MBA were not detected. Neither single nor repeated ip. administration of different amounts of saline before bile sampling nor oral water supply within the bile collection period influenced the bile flow and excretion of DBA and TBA. Phenobarbital administration (60 mg/kg b.w. ip.) 2 hrs before bile sampling did not influence bile flow and bile acid (BA) excretion. After 3 days pretreatment with phenobarbital (3 X 60 mg/kg b.w. ip.) the bile flow was somewhat increased, BA-excretion was unchanged and the relation TBA/DBA diminished. Chlorpromazine administration (40 mg/kg b.w. ip.) 1,5 hrs before bile sampling decreased bile flow and BA excretion within the first collection period, whereas bile flow and BA excretion increased in the thrid collection period. No signs of cholestasis were observed after chlorpromazine pretreatment once a day for 3 days. Bile flow and BA excretion were increased and the relation TBA/DBA was unchanged.
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PMID:[Effect of phenobarbital and chlorpromazine on bile flow and bile acid excretion in male Wistar rats]. 70 25

To define the relationship of bile acid retention to the pruritus of cholestasis, we quantified individual bile acids in serum, acetone swabs of skin, and skin tissue in 13 patients with cholestasis undergoing laparotomy and in 8 controls. There was no consistent relationship between pruritus and concentrations of either total or individual bile acids in serum. Skin tissue concentrations of bile acids were elevated in patients with cholestasis, were linearly related to serum levels, and did not differentiate between those patients with and those without pruritus. Concentrations of bile acids on the skin surface, which were lower than those reported by others, did not correlate with pruritus, and were decreased by simple soap and water washing. These data indicate that the pruritus of cholestasis is not directly related to the skin tissue concentration of any of the major bile acids, although a relationship to a particular molecular form of bile acids could not be excluded.
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PMID:Elevations in skin tissue levels of bile acids in human cholestasis: relation to serum levels and topruritus. 90 91

C-terminal octapeptide of cholecystokinin was administered at six dose levels, 4-128 ng/kg, by 184 intravenous injections to three mongrel dogs under several pressure conditions of the biliary system. Gallbladder contraction was monitored radiographically. A good, dose-dependent contraction response resulted with intraductal pressures of 0 and 10 cm water. At 20 cm water, a markedly reduced and dose-independent response occurred. No contraction response was found with an intraductal pressure of 30 cm water. This animal experimental work suggests that in man, a contraction response of 30% or more may rule out significant common bile duct obstruction.
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PMID:Contraction of the canine gallbladder in different degrees of common bile duct obstruction. 113 82

The application of alpha-cyclodextrin (alpha-CD) as an alternative vehicle for water insoluble and volatile chemicals was investigated in toxicity studies of p-chloro-alpha, alpha, alpha-trifluorotoluene (CTFT). Groups of F344 rats and B6C3F1 mice of each sex were administered CTFT (97% pure) by gavage in either corn oil or alpha-CD aqueous formulations daily for 14 consecutive days. The dose levels used were 10 (mice only), 50, 400, and 1000 mg/kg for corn oil vehicle and 10, 50, and 400 mg/kg (maximum achievable dose at gavage volume of 5 ml/kg) for alpha-CD vehicle. With both vehicles CTFT and alpha 2u-globulin were found to accumulate in the male rat kidney after 14 days of exposure and a dose-related toxic nephropathy was observed at dose of 50 mg/kg or higher. The hepatocellular hypertrophy and cytoplasmic vacuolation of the adrenal cortex which appeared in dosed male and female rats were also found to be independent of vehicle. Clinical pathology findings suggested a mild anemia and cholestasis in rats. With both vehicles no tissue bioaccumulation of CTFT was found in male or female mice. Vehicle-independent hepatocellular hypertrophy and cholestasis were also observed in mice at doses of 400 and 1000 mg/kg. In conclusion, the alpha-CD vehicle does not affect the toxic responses of CTFT in both sexes of both species. The results of the studies suggest that alpha-CD may be an appropriate alternative vehicle for toxicity studies.
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PMID:Application of molecular encapsulation for toxicology studies: comparative toxicity of p-Chloro-alpha, alpha, alpha-trifluorotoluene in alpha-cyclodextrin vehicle versus corn oil vehicle in male and female Fischer 344 rats and B6C3F1 mice. 137 21

Using the ANIT induced model of cholestasis in rats, the therapeutic effects of UDCA to the intrahepatic cholestasis were evaluated by changes of serum chemistry and liver histology. ANIT was administered once at a dosage of 40 mg/kg b.w. per os and UDCA was given ad libitum for 7 days by a drinking water containing UDCA at 0.5 and 5.0% solution. In the period of bile duct epithelial degeneration and necrosis, effects of UDCA for jaundice was not detected, but hepato-cellular disturbances were appeared histologically. Moreover, the elevation of serum levels of chenodeoxy-cholic acid, deoxycholic acid and lithocholic acid was accompanied. On the other hand, in the recovery stage of the bile duct epithelium, serum bilirubin was decreased significantly in the UDCA group which seemed to be related with the potent choleretic effect of UDCA. These results may indicate that UDCA is effective for the intrahepatic cholestasis in the case with no bile duct epithelial damage but in the presence of it hepato-cellular injury is introduced by the accumulated toxic bile acids in the blood.
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PMID:[Effects of urso-deoxycholic acid (UDCA) on alpha-naphthyl-isothiocyanate (ANIT) induced intrahepatic cholestasis in rats]. 140 70

Rickets and osteopenia, common problems in chronic childhood cholestasis, have been attributed to vitamin D malabsorption leading to reduced serum levels of 25(OH)-vitamin D. d-alpha-Tocopheryl polyethylene glycol-1000 succinate (TPGS), a water-soluble form of vitamin E, forms micelles at low concentration. We evaluated the potential role of TPGS in enhancing vitamin D absorption in eight children (aged 5 mo to 19 y) with severe chronic cholestasis (three extrahepatic biliary atresia, three nonsyndromic intrahepatic cholestasis, and two Alagille syndrome). To evaluate vitamin D absorption, the subjects received vitamin D3 1000 IU/kg (maximum dose of 50,000 IU); they then received the same dose of vitamin D3 mixed with TPGS (25 IU/kg). Serial serum vitamin D3 levels and areas under the curve were measured. All patients had enhanced absorption of vitamin D when it was administered in a mixture with TPGS. Mean area under the curve for serum vitamin D3 was 403.0 +/- 83.1 nmol x h/L (155.6 +/- 32.1 ng x h/mL), with a mean rise above baseline of 13.5 +/- 1.8 nmol/L (5.2 +/- 0.7 ng/mL) with vitamin D/TPGS compared with no rise when vitamin D was given alone (both p less than 0.001). Seven patients have been followed for at least 3 mo while receiving the vitamin D/TPGS combination. Those with initially low serum 25(OH)-vitamin D levels (less than 37.5 nmol/L or 15 ng/mL) had normalization (range 37.5-146 nmol/L) within 1 mo, whereas those with initially normal levels remained normal. While the patients were receiving vitamin D/TPGS, serum vitamin E to total lipid ratio either normalized or remained normal.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:d-Alpha-tocopheryl polyethylene glycol-1000 succinate enhances the absorption of vitamin D in chronic cholestatic liver disease of infancy and childhood. 154 43

To our knowledge this is the first report of rat bile duct cannulations in which the distal cannula is hemisected but extends to the sphincter of Oddi. It is minimally invasive and requires only about 45 minutes preparation time. In contrast to studies described in the literature, enterohepatic recirculation remains intact but bile can always be separated from pancreatic secretions at investigator discretion in the model. In addition, biliary flow and pressure can be measured without compromise. Acute biliary secretory pressure, under anesthesia, was 17 cm water. Bile flow, averaging 9.6 microliters/min/100 g was measured in unanesthetized rats surviving for 2 weeks (60% of animals monitored). Gross necropsy findings indicated that animals dying in less than 7 days usually suffered bile peritonitis subsequent to catheter rupture of the bile duct or loss from the ligature restraint. Deaths after 2 weeks were usually related to cholestasis due to blockage of the catheter with mineral debris and/or duct tissue. A detailed literature review of bile duct cannulation in rats has been made.
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PMID:Chronic bile duct cannulation in laboratory rats. 166 54

Many childhood recipients of liver transplantation require massive doses of cyclosporin to achieve therapeutic blood concentrations of the drug. The impaired absorption of this strongly lipophilic drug may be due to reduced intestinal absorptive area, suboptimal mixing of the drug with hepatobiliary secretions, or residual cholestasis. Improvement of cyclosporin absorption was sought by means of oral coadministration of d-alpha-tocopheryl-polyethylene-glycol-1000 succinate (TPGS), a water-soluble form of vitamin E which can form micelles. 25 mg/kg daily of TPGS was given to six paediatric liver transplant recipients and one young adult with severe hepatobiliary graft-vs-host disease after bone-marrow transplantation, who required 29-136 mg/kg cyclosporin daily to achieve therapeutic cyclosporin blood concentrations. Five responded; the oral cyclosporin dose could be reduced by 40-72% within 2 months. In addition, intravenous cyclosporin was stopped in two of the responders. In the two non-responders the cyclosporin doses at entry were similar to those in the responders after TPGS treatment. Oral cyclosporin absorption tests correctly predicted the outcome of treatment in three responders and one non-responder tested. Treatment with TPGS to enhance cyclosporin absorption might be a useful way of reducing the high cost of immunosuppression in paediatric liver transplant recipients.
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PMID:Improvement of cyclosporin absorption in children after liver transplantation by means of water-soluble vitamin E. 167 98

Sugar absorption by the biliary ductular epithelium under steady-state conditions was examined using isolated perfused rat liver. The test sugar and mannitol (as a putative marker of paracellular entry) were added to the glucose-free recirculating perfusate each at a concentration of 5 mmol/L, and apparent active biliary ductular absorption equated with the change in concentration of the test sugar relative to that of mannitol. A metabolizable hexose (D-glucose), pentose (D-xylose), and three nonmetabolizable hexoses (alpha-methyl-glucoside, 3-o-methyl-glucose, and L-glucose) were used. All five monosaccharides were well absorbed at constant rates for 2 hours with apparent rates of absorption (mumol.kg body weight-1.min-1, mean +/- SE) of D-glucose, 0.24 +/- 0.01; L-glucose, 0.20 +/- 0.02; 3-o-methyl-glucose, 0.19 +/- 0.02; alpha-methyl-glucoside, 0.16 +/- 0.03; and D-xylose, 0.10 +/- 0.04. The addition of phloridzin to the perfusate inhibited D-glucose absorption in part but did not inhibit L-glucose absorption. When perfusate Na+ was replaced by N-methylglucamine, the bile-plasma ratio of mannitol remained unchanged, as did the apparent absorption rate of D-glucose and 3-o-methyl-glucose. In contrast, absorption of L-glucose and alpha-methyl-D-glucoside gradually ceased. The addition of 15 mmol/L glucose to the perfusate caused decreased bile flow and increased taurocholate concentration in bile, suggesting that glucose absorption by the biliary ductules induced water reabsorption. It is concluded that sugars are absorbed by the biliary ductular system by Na(+)-dependent and Na(+)-independent transport systems, the substrate affinities of which differ from those reported for apical membrane hexose transport systems in renal tubular and intestinal epithelia. Ductular absorption of solutes such as glucose that enter bile passively may have biological use, because ductular absorption decreases the concentration of substrates for bacterial growth in gallbladder bile. On the other hand, ductular absorption of solutes induces reabsorption of biliary water, resulting in decreased bile flow; this might contribute to cholestasis during prolonged hyperalimentation with solutions containing glucose.
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PMID:Sugar absorption by the biliary ductular epithelium of the rat: evidence for two transport systems. 158 53


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