Assessment of biliary excretion of piperacillin-tazobactam in humans.

Piperacillin-tazobactam concentrations in serum and bile were measured intraoperatively in 10 patients undergoing cholecystectomy (group 1) and 5 cholecystectomized patients provided with external bile duct drainage (group 2). Each patient received a single intravenous dose of piperacillin at 4 g plus tazobactam at 0.5 g over 30 min. Drug concentrations in both serum and bile were measured by high-performance liquid chromatography. In group 1 patients, serum and bile specimens and gallbladder wall fragments were collected at mean times of 70 and 83 min postinfusion, respectively. The mean concentrations of piperacillin and tazobactam were, respectively, 69.1 +/- 41.5 (standard deviation) and 9.9 +/- 5.1 microg/ml in serum, 630.4 microg/ml (range, 24.8 to 1,194 microg/ml) and 11.8 microg/ml (range, 3.6 to 22 microg/ml) in choledochal bile, 342.3 microg/ml (range, 1.1 to 1,149 microg/ml) and 7.7 microg/ml, (range, 0.2 to 23.1 microg/ml) in gallbladder bile, and 49.3 microg/g (range, 9.7 to 223 microg/g) and 2.9 microg/g (range, 0.1 to 5.9 microg/g) in the gallbladder wall. In group 2 patients, the amounts of drugs recovered in bile drainage obtained over 12 h were 28.4 +/- 18.0 and 1.0 +/- 0.5 mg for piperacillin and tazobactam, respectively. Peak piperacillin and tazobactam concentrations in bile reached 358 +/- 242 and 10.8 +/- 4.2 microg/ml, respectively. Comparison of drug levels in serum and bile suggests an underlying active secretion process for piperacillin elimination into the bile, unlike that of tazobactam. From a therapeutic viewpoint, given the concentrations of tazobactam recorded in bile fluid and tissue, the addition of this beta-lactamase inhibitor to piperacillin therapy might be of interest in the management of biliary tract infections, mostly in patients at risk of mixed aerobic-anaerobic infections due to beta-lactamase-producing organisms.     

Piperacillin distribution into bile, gallbladder wall, abdominal skeletal muscle, and adipose tissue in surgical patients.

The concentrations of piperacillin in serum, bile, gallbladder wall, abdominal skeletal muscle, and adipose tissue were measured simultaneously at various times after the intravenous administration of a single 5-g dose to each of 14 patients undergoing biliary tract surgery. Piperacillin concentrated in the bile with peak levels exceeding 4,000 micrograms/ml. In a single patient with cystic duct obstruction, trace gallbladder bile piperacillin levels were measured. Gallbladder wall concentrations of piperacillin tended to be higher than corresponding serum concentrations, with a correlation observed between tissue values and the degree of acute gallbladder inflammation and gallbladder bile piperacillin concentrations. Mean peak muscle and adipose tissue piperacillin concentrations of 31 and 27 micrograms/g, respectively, were reached at between 2 and 3 h after the start of infusion. These concentrations exceeded the minimum inhibitory concentration for a majority of susceptible organisms. A single 5-g dose of piperacillin achieved therapeutic levels in gallbladder wall, intraabdominal skeletal muscle, and adipose tissue and concentrated in the bile of patients with patent biliary tracts.     

Biliary levels of ceforanide.

Ceforanide levels in plasma, gallbladder bile, gallbladder tissue, and common bile duct were studied in 10 patients with normal biliary tracts and in 35 patients with biliary disease at various intervals after intravenous injection of 1 g of the drug. Peak blood levels were obtained within 1 h of administration (mean, 67 +/- 15 micrograms/ml). Patients with a normal bilary tract, as well as patients with chronic cholecystitis and a patent cystic duct, achieved high gallbladder bile levels of ceforanide within 2 h (mean, 76 +/- 25 micrograms/ml) and attained even higher levels by 4 h (mean, 182 +/- 51 micrograms/ml). However, all patients with chronic cholecystitis and an occluded cystic duct had very low drug concentrations in the gallbladder bile (14 +/- 7 micrograms/ml at 2 h). Despite this difference in gallbladder bile levels, ceforanide levels of 21 +/- 3 micrograms/g were achieved at 1 to 3 h in gallbladder tissue in both groups with chronic cholecystitis. The concentration of ceforanide in common bile duct was 149 +/- 59 micrograms/ml at 2 h after administration, with levels over 60 micrograms/ml present from 1 to 4 h after administration. These results indicate that ceforanide reaches high levels in the biliary tract. Its potential value in the prevention and treatment of biliary infections should be assessed.     

Biliary excretion of ceftizoxime in humans

Biliary concentrations of a new cephalosporin, ceftizoxime, were measured in bile collected in 8 cholecystectomized patients provided with T-tube drainage and in 14 patients where bile was obtained by puncture of the gall bladder and choledochus during cholecystectomy. In patients with external biliary drainage, a mean biliary peak of 150.3 +/- SEM 49.8 micrograms/ml has been observed 2 h after intravenous injection of 2 g of ceftizoxime; the antibiotic activity amounted still to 17.3 +/- 6.0 micrograms/ml after 6 h. Assays performed during operation showed the following simultaneous concentrations 1 h after 2 g of ceftizoxime given intravenously: serum: 85.3 +/- 8.1 micrograms/ml; main duct bile: 279.8 +/- 40.0 micrograms/ml; gallbladder bile: 119.9 +/- 19.4 micrograms/ml. These findings were compared with the biliary excretion of 8 other cephalosporins studied previously under the same conditions. The results of the present study suggest that administration of ceftizoxime may be effective in the treatment of biliary tract infections.     

Effects of chlorpromazine hydrochloride on bile salt synthesis, bile formation and biliary lipid secretion in the Rhesus monkey: a model for chlorpromazine-induced cholestasis

We studied the acute effects of intravenous infusions of chlorpromazine hydrochloride on bile salt synthesis, bile formation and biliary lipid secretion in the alert female Rhesus monkey prepared with a total biliary fistula and in a steady bile salt secretory state. In twelve studies (three animals), five doses of radiolabelled chlorpromazine hydrochloride (1-10 mg identical to 2.8-28 mumol/kg) were infused intravenously for 1 h in random order. Cholestasis was induced within minutes in all experiments. The radiolabel appeared rapidly in bile, with similar recoveries in bile and urine and a 90% total cumulative output in 4 days. Both bile flow, bile salt and other biliary lipid outputs were inhibited in a dose related and reversible manner. The apparent bile salt independent bile flow was consistently abolished, and a prompt return to basal values occurred when biliary concentration of the drug and metabolities fell below 1-2 mM. When chlorpromazine hydrochloride was infused at three doses (2.5, 5.0 and 10.0 mg identical to 7-28 mumol/kg) during constant intravenous infusion of 14C sodium taurocholate (300 mumol/h), bile flow, total bile salt output and 14C taurocholate output decreased within minutes. This was accompanied by a progressive rise in the serum 14C taurocholate concentration. After 90 min the taurocholate specific activity in bile increased significantly indicating that bile salt synthesis was inhibited. Secretion of retained bile salts and reversal of inhibition of bile salt synthesis occurred with time: the course of both events was correlated with the dose of the drug. Thus, in monkeys, chlorpromazine hydrochloride induces reversible, dose related cholestasis suppression of the bile salt dependent and independent flow, inhibition of bile salt synthesis and impairment of biliary lipid secretion. We suggest that these effects are due to both bile salt-chlorpromazine interactions and the effect of the latter on canalicular and other membranes.     

High hepatic excretion in humans of cefpiramide, a new cephalosporin.

After intravenous administration of 1 g of cefpiramide, the biliary elimination of the drug was studied by using high-performance liquid chromatography. In five healthy volunteers, a mean peak concentration of 339 +/- 107 (standard error of the mean) micrograms/ml was measured in aspirated duodenal fluid during h 2 after administration, and 1.2% of the dose given was recovered over a 4-h period. A maximal concentration of 1,161 +/- 392 micrograms/ml was reached during h 2 in T-tube bile from 10 recently cholecystectomized patients, with a 24-h biliary recovery of 23.1%; urinary recovery over the same period averaged 49.4%. In 10 patients undergoing cholecystectomy, the concentrations in serum, choledochal bile, gallbladder bile, and gallbladder wall 1 h after cefpiramide administration were 157 +/- 21, 1,726 +/- 501, and 84 +/- 33 micrograms/ml and 23 +/- 4 micrograms/g, respectively. These figures represent the highest biliary concentrations attained so far with a beta-lactam antibiotic and are therefore a good prerequisite for treatment of biliary tract infections with cefpiramide.     

Biliary concentrations of piperacillin in patients undergoing cholecystectomy.

Piperacillin is a new semisynthetic, expanded-spectrum penicillin with marked activity against Pseudomonas aeruginosa. The biliary excretion of piperacillin was studied in patients undergoing cholecystectomy. Concentrations of piperacillin in common duct bile at 35 to 90 min postinfusion of 1-g doses ranged from 31 to 920 micrograms/ml, with a mean (+/- standard deviation) of 467 +/- 363 micrograms/ml. Gallbladder piperacillin levels at 30 to 75 min postinfusion ranged from 2.2 to 80 micrograms/ml, with a mean of 27 +/- 31 micrograms/ml. No correlation occurred with peak serum level of antibiotic, creatinine, bilirubin, or alkaline phosphatase. Significant amounts of piperacillin were excreted via the biliary system.     

Biliary excretion of rufloxacin in humans.

Rufloxacin is a new once-daily antibacterial fluoroquinolone with a long half-life. The aim of the present study was to evaluate the plasma and biliary kinetics and biliary and urinary excretion of rufloxacin in patients with extrahepatic cholestasis. Twelve patients with total external percutaneous transhepatic biliary drainage were given a single oral dose of 400 mg of rufloxacin. Plasma, bile, and urine samples and fractions were collected over 72 h after drug administration. Rufloxacin and its major metabolite, the N-desmethyl derivative, were measured by high-performance liquid chromatography. Maximum rufloxacin concentrations in plasma and bile (means +/- standard deviations) were 4.05 +/- 1.38 micrograms/ml and 8.24 +/- 7.16 micrograms/ml, respectively, and were reached in 4.2 +/- 3.0 h and 4.2 +/- 3.5 h, respectively. The terminal elimination half-life of rufloxacin in plasma was 45.1 +/- 13.5 h. Apparent plasma clearance was 31.3 +/- 10.5 ml/min, while biliary clearance was 0.4 +/- 0.2 ml/min and renal clearance was 12.7 +/- 6.0 ml/min. In 72 h, 0.9% +/- 0.8% of the dose given was recovered in bile and 27.2% +/- 12.0% was recovered in urine. Biliary concentrations exceeded the MICs of most common biliary tract pathogens for at least 24 h after administration. The broad antibacterial spectrum of rufloxacin and its high and prolonged biliary concentrations suggest that this drug may be useful for treatment of biliary tract infections.     

Biliary excretion of ciprofloxacin and piperacillin in the obstructed biliary tract.

Biliary excretion of ciprofloxacin and piperacillin was determined in cholestatic patients who had undergone endoscopic cholangiography. The median concentration of ciprofloxacin (n = 9) was 2.36 micrograms/ml (range, 0.29 to 19.8 micrograms/ml) in bile compared with 1.66 micrograms/ml (range, 0.73 to 2.69 micrograms/ml) in serum. The median concentration of piperacillin (n = 7) was < 5 micrograms/ml (range, < 5 to 26) in bile compared with 14.3 micrograms/ml (range, 5.3 to 80) in serum. Ciprofloxacin, but not piperacillin, can be actively excreted into bile in the presence of a biliary tract obstruction.     

Biliary elimination of cefotiam, an experimental and clinical study

Five isolated rabbit livers were in vitro perfused over a 3-hour period. After addition of 10 mg of cefotiam to the circulating blood, a biliary peak concentration of 76.2 +/- 14.2 micrograms/ml (mean +/- SEM) was reached between the 90th and 120th min; 3.1 +/- 0.4% of the dose given was excreted in the bile during the 3-hour period. In 10 recently cholecystectomized patients provided with a T-tube drain, 1 g of cefotiam was given intravenously. A biliary peak concentration of 340 +/- 81 micrograms/ml was observed 2 h later. 1.8 +/- 0.7% of the administered dose was recovered in the bile during the 12-hour period. In 5 clinically normal subjects given intravenously 1 g of cefotiam, 0.5 +/- 0.2% of the administered dose was found in the duodenal fluid aspirated over a 4-hour period. Cefotiam concentrations measured in choledochal and gallbladder bile collected simultaneously during operation 1 h after intravenous administration of 1 g of the drug to 10 patients were 502 +/- 102 micrograms/ml and 143 +/- 39 micrograms/ml, respectively; they exceeded significantly the concentration determined in the serum sampled at the same time (17.9 +/- 2.6 micrograms/ml). The biliary parameters of cefotiam were compared with those of 14 other beta-lactam antibiotics previously studied by the same procedure. The results of the present study are consistent with a possible beneficial effect of cefotiam in the treatment of biliary tract infections.     

Evaluation of a surgical procedure to measure drug biliary excretion of rats in regulatory safety studies

A surgical procedure was evaluated to allow bile collection from the freely moving male Sprague-Dawley rats for the assessment of drug biliary excretion during regulatory safety studies. A catheter was implanted into the bile duct to divert the bile flow via an exteriorized loop. Following recovery from the surgery and verification of normal hepatic function, the exteriorized catheter was sectioned to allow collection of the bile and replacement with a commercial bile salt solution. Approximately 80% of the catheterized animals (10 females and 10 males) had normal serum liver enzyme levels 2 days after surgery. Then, the effect of acute or repeated administrations of the immunosuppressant tacrolimus on the biliary excretion of 14C diazepam was studied to validate the technique. A first group of 12 rats received an intravenous injection of 10 mg/kg 14C-diazepam and the total and sequential amounts of diazepam excreted in the bile were measured over 72 h. Biliary excretion accounted for 80% of diazepam elimination. These rats were then given an oral administration of 3 mg/kg tacrolimus on days 7 and 8 followed by the same intravenous dose of 14C-diazepam. Another group of 10 catheterized rats was given 21 daily oral doses of 3 mg/kg tacrolimus followed by a single intravenous administration of 14C-diazepam. No significant changes in diazepam biliary excretion were observed following either acute or repeated administration of tacrolimus. This study demonstrates the feasibility of drug biliary excretion investigations under Good Laboratory Practices conditions as a complement to regulatory acute or repeated dose safety studies.     

A study of the penetration of meropenem into bile using endoscopic retrograde cholangiography.

One gram of meropenem was administered as prophylaxis to patients undergoing endoscopic retrograde cholangiography (ERC) in a study of the bile pharmacokinetics of this agent. Twenty-four patients were evaluated and a single bile sample was collected from each one during ERC at different time intervals following intravenous infusion. Bile concentrations after the dose ranged from 0.7 to 25.7 mg/L (mean 11.1) and exceeded the MIC90s for the pathogens most commonly associated with biliary tract infections for up to 203 mins. The bile concentrations of 13 patients with biliary tree obstruction were compared with those of 11 patients without obstruction. Bile concentrations in excess of the MIC90s for the predominant pathogens were achieved in both groups; a positive correlation between meropenem bile concentration and the time of dose administration was demonstrable only for the obstructed group. ERC may be a useful technique for biliary pharmacokinetic studies.     

Evaluation of the biliary excretion of pencillin G.

Biliary excretion of penicillin G was studied experimentally by perfusion of isolated rabbit liver. Under these conditions, bile recovery accounted for 5% of the amount of penicillin G added to the perfusing blood (10 mg). In man, after intravenous administration of a 599-mg dose of penicillin G (1,000,000 U) to patients provided with T-tube drainage (n = 10), the maximum biliary level averaged 18.0 +/- 8.0 microgram/ml at 2 h; biliary recovery of penicillin G accounted for 0.12% of the administered dose. The excretion of penicillin G in the juice collected through duodenal tubing in normal subjects averaged 0.07% of the administered dose. Peroperative assays showed that the concentrations determined 1 h after intravenous administration 599 mg of the drug attained 45.7 +/- 16.7 microgram/ml in the gallbladder bile and 93.5 +/- 16.3 microgram/ml in the common-duct bile.     

A comparative study of intravenous cholangiography and99mTc-pyridoxylideneglutamate in patients with hepatobiliary disease

The purpose of this investigation was to compare the diagnostic value of intravenous cholangiography with^99mTc-pyridoxylideneglutamate, a new radioisotopic biliary imaging agent, in 15 patients with suspected hepatobiliary disease. Each subject had both examinations, and the studies were interpreted independently. The results suggest that intravenous cholangiography may provide more specific information about the ductal system but is of limited value in patients with elevated bilirubin. In these patients^99mTc-pyridoxylideneglutamate may show patency of the bile ducts and distinguish between partial and complete biliary tract obstruction. Depending upon the serum bilirubin level, both studies may provide useful and complementary information about the biliary tract.Picker Scholar, James Picker Foundation     

Alteration of drug metabolism during cholestasis in man.

The morphological and functional alterations of the smooth endoplasmic reticulum of the liver cell related to biliary stasis have brought attention to drug biotransformation during cholestasis. The metabolism of meprobamate, pentobarbital and tolbutamide was assessed in subjects with intrahepatic recurrent cholestasis (3), cholestatic hepatitis (6), extrahepatic biliary obstruction (7) and normal controls (16). In the patients with recurrent intrahepatic cholestasis no differences in drug metabolism were noted as compared to the control group. In cholestatic hepatitis the plasma half-lives of meprobamate (828 +/- 422 min.) and pentobarbital (39+-65) were significantly longer than in in controls (444 +/- 37 and 25.4 +/- 1.1 respectively). Tolbutamide plasma half-life appeared unchanged. The most striking variations were observed in the patients with extrahepatic biliary obstruction. In such cases while meprobamate half-life was unchanged, pentobarbital half-life was significantly prolonged (31.2 +/- 2.5) and the in vitro metabolism of the drug, using liver preparations, was decreased to less than 50% of the control value. In contrast the metabolism of tolbutamide was accelerated as evidenced by a significant decrease of plasma half-life (165 +/- 48 min. versus 384 +/- 76 of the controls) and an enhanced urinary excretion of the drug's metabolites. However the metabolism of tolbutamide in vitro did not show any difference between normal and cholestatic liver. Whatever the mechanism of the peculiar behaviour of tolbutamide in extrahepatic biliary obstruction it seems to be related to the increased bile dalt concentration during cholestasis. In fact the low values of plasma half-life increase significantly either relieving the biliary obstruction or producing a bile salt depletion with cholestyramine. Preliminary results in vitro suggest the bile salt could displace tolbutamide from albumin binding thus increasing the amount of free drug available for biotransformation by the liver. In conclusion cholestasis may affect drug metabolism depending on the degree of biliary stasis, liver cell injury and the type of drug tested. The mechanism could be that of an impaired biotransformation in the smooth endoplasmic reticulum or could involve extrahepatic factors.     

Pharmacological Study of Cefazolin During Intermittent and Continuous Infusion: a Crossover Investigation in Humans

Levels of cefazolin were determined in plasma, urine, bile, and cerebrospinal fluid in humans after a bolus intravenous injection and during a controlled, continuous intravenous infusion. All the patients were studied in a steady-state and crossover fashion. In plasma, the mean peak level after bolus injection (1.5 g) studied in 12 patients was 206.5 μg/ml; during continuous infusion (6 g daily), the mean level remained stable at 52.6 μg/ml. With bolus injection and continuous infusion, respectively, 89.7 and 86.3% of the administered dose of cefazolin were excreted in the urine of nine patients over the 6-h period considered. The levels of cefazolin in common bile duct bile were studied in six cholecystectomized patients. In bile collected during the two 3-h periods of the experiment, the mean concentration of the drug in the bile after bolus injection was 66.9 and 22.0 μg/ml, respectively; during continuous infusion, the corresponding biliary levels were 50.7 and 51.3 μg/ml, respectively. In four neurosurgical patients with an intraventricular catheter, neither bolus injection nor continuous infusion resulted in a demonstrable concentration of cefazolin in the cerebrospinal fluid. The continuous intravenous administration of cefazolin might have some advantage over the intravenous bolus intermittent injections. In plasma, the area under the curve is greater with continuous infusion than with bolus injection. In bile, the levels of cefazolin are more sustained with continuous infusion than with bolus injection. This approach to intravenous administration of cefazolin deserves more pharmacological and clinical trials.     

Alteration of Drug Metabolism During Cholestasis in Man*

Abstract. The morphological and functional alterations of the smooth endoplasmic reticulum of the liver cell related to biliary stasis have brought attention to drug biotransformation during cholestasis. The metabolism of meprobamate, pentobarbital and tolbutamide was assessed in subjects with intrahepatic recurrent cholestasis (3), cholestatic hepatitis (6), extrahepatic biliary obstruction (7) and normal controls (16). In the patients with recurrent intrahepatic cholestasis no differences in drug metabolism were noted as compared to the control group. In cholestatic hepatitis the plasma half-lives of meprobamate (828 ± 422 min.) and pentobarbital (39 ±6. 5 hours) were significantly longer than in controls (444 ± 37 and 25. 4 ± 1. 1 respectively). Tolbutamide plasma half-life appeared unchanged. The most striking variations were observed in the patients with extrahepatic biliary obstruction. In such cases while meprobamate half-life was unchanged, pentobarbital half-life was significantly prolonged (31. 2 + 2. 5) and the in vitro metabolism of the drug, using liver preparations, was decreased to less than 50 % of the control value. In contrast the metabolism of tolbutamide was accelerated as evidenced by a significant decrease of plasma half-life (165 ± 48 min. versus 384 ± 76 of the controls) and an enhanced urinary excretion of the drug's metabolites. However the metabolism of tolbutamide in vitro did not show any difference between normal and cholestatic liver. Whatever the mechanism of the peculiar behaviour of tolbutamide in extrahepatic biliary obstruction it seems to be related to the increased bile salt concentration during cholestasis. In fact the low values of plasma half-life increase significantly either relieving the biliary obstruction or producing a bile salt depletion with cholestyramine. Preliminary results in vitro suggest the bile salt could displace tolbutamide from albumin binding thus increasing the amount of free drug available for biotransformation by the liver. In conclusion cholestasis may affect drug metabolism depending on the degree of biliary stasis, liver cell injury and the type of drug tested. The mechanism could be that of an impaired biotransformation in the smooth endoplasmic reticulum or could involve extrahepatic factors.     

Hepatobiliary kinetics and excretion of ciprofloxacin.

The biliary excretion and metabolism of ciprofloxacin was studied in 25 hospitalized patients: 19 undergoing routine cholecystectomy and 6 with indwelling biliary drainage catheters. An intravenous dose of 200 mg of ciprofloxacin given 2.5 to 3.0 h prior to cholecystectomy resulted in concentrations in common duct bile, gallbladder bile, and gallbladder wall of 5.69 +/- 4.8, 5.43 +/- 3.34, and 2.52 +/- 1.30 micrograms/g, respectively, all at least fourfold greater than simultaneous concentrations in serum. Ciprofloxacin concentrations in common duct bile exceeded peak concentrations in serum in all but two patients with common duct obstruction. Multiple preoperative doses of ciprofloxacin prior to cholecystectomy increased concentrations in gallbladder bile by eightfold. Six patients with indwelling biliary drainage catheters also received 200 mg of ciprofloxacin intravenously. Less than 1% of the administered dose was excreted in bile as unchanged ciprofloxacin, and there was extensive metabolism. However, peak ciprofloxacin concentrations of 2.83 +/- 0.76 micrograms/ml in serum produced peak concentrations of 10.69 +/- 5.30 micrograms/ml in bile within 1.5 h after infusion and maintained concentrations of at least 0.5 microgram/ml in common duct bile for over 12 h in all patients. It appears that ciprofloxacin concentrations in bile will exceed the MICs for most susceptible biliary pathogens for a period of at least 12 h after a 200-mg intravenous dose.     

Acute effects of HMG-CoA reductase inhibitors on biliary lipids in patients with interrupted enterohepatic circulation

HMG-CoA reductase inhibitors decrease serum cholesterol by inhibiting hepatic cholesterol synthesis, but their influence on biliary lipids is not well characterized. In the present study Pravastatin (80 mg) was administered as a single oral dose to 10 patients with external bile fistula, after 1 week of interruption of the enterohepatic circulation, in order to assess the effect of inhibition of hepatic cholesterol synthesis on biliary lipids in conditions of stimulated bile acid synthesis. Bile was collected every hour for 12 h. On the day before, the same procedure was applied with a placebo, and collected bile used as control. Pravastatin decreased both bile acid and phospholipid concentration to about 60% of basal values; this change was still significant after 10 h. Cholesterol concentration was also decreased to about 70% of basal values, but this change was significant only from the 5th to the 7th h. The per cent of cholic and chenodeoxycholic acid was not affected by the drug, but the ratio of glyco- to tauroconjugated bile acids was decreased to about half the initial values. Bilirubin concentration exhibited a late increase, suggesting a reduction in the bile flow. These results suggest that, in patients with interrupted enterohepatic circulation, biliary excretion of bile acids can be largely dependent on hepatic cholesterol synthesis.     

大鼠胆管缺血狭窄模型的构建

背景：有研究表明可以用钳夹法制作心肌缺血再灌注损伤模型。目的：采用钳夹法建立大鼠胆管缺血狭窄动物模型。方法：将Wistar大鼠随机分为假手术组和模型组,模型组用2枚显微血管夹夹闭一段长约0.8cm的胆总管90min,假手术组仅暴露胆管未夹闭。术后21d两组大鼠均经静脉胆道造影,下腔静脉取血,分离血清进行总胆红素及直接胆红素浓度测定。结果与结论：模型组钳夹部位以上胆管明显扩张,静脉胆管造影示胆管扩张,壁光滑,狭窄部位以下胆管未显影。3只（16.7%）胆道未显影,但解剖动物时发现其肝脏肿大,微呈绿色,钳夹处胆总管闭锁,胆总管扩张。模型组血清总胆红素及直接胆红素高于假手术组（P〈0.05）。结果证实,实验采用血管夹钳闭缺血法成功构建了大鼠胆管缺血狭窄模型。