Biomedical subjects
M F Stolk
Publications and source records attributed to M F Stolk.
Absence of apolipoprotein E4 genotype, good gallbladder motility and presence of solitary stones delay rather than prevent gallstone recurrence after extracorporeal shock wave lithotripsy.
BACKGROUND/AIMS: Extracorporeal shock wave lithotripsy (ESWL) with adjuvant bile salt dissolution therapy may be successful in selected gallstone patients, but the considerable risk of recurrence is a major drawback. Apolipoprotein E4 genotype and impaired gallbladder motility have been identified as major risk factors for recurrence during short-term follow up. We have now examined their relevance during long-term follow up. METHODS: Eighty-four cholesterol gallstone patients (55 solitary and 29 multiple (two to ten) stones) were followed prospectively up to 10 years after complete stone disappearance. Various potential risk factors for recurrence were evaluated. RESULTS: Gallstone recurrence was found in up to 80% of patients at 10 years follow-up. Absence of the apolipoprotein epsilon4 allele, initial solitary stones, good gallbladder emptying (i.e. minimal postprandial volume < or = 6 ml) and 2-year postdissolution ursodeoxycholic acid prophylaxis (in ten patients) all delayed but did not prevent recurrence. In contrast, regular use of non-steroidal anti-inflammatory drugs (NSAIDs) was identified as an independent protective factor, with greatly decreased recurrence (at 10 years: 58 vs 93% in non-NSAID users, P = 0.03). CONCLUSIONS: Non-apolipoprotein E4 genotype, presence of solitary stones and good gallbladder emptying delay rather than prevent recurrence after initially successful ESWL. Regular use of NSAIDs may prevent recurrence.
Interdigestive gallbladder emptying, antroduodenal motility, and motilin release patterns are altered in cholesterol gallstone patients.
The role of interdigestive gallbladder emptying in gallstone formation is unknown. In fasting healthy subjects, gallbladder emptying is associated with antral phase III of the migrating motor complex (MMC) and high plasma motilin. Therefore, gallbladder volumes and motilin levels were measured during 13 MMC cycles in 10 cholesterol gallstone patients and compared with 20 MMC cycles in 10 healthy subjects. MMC cycle length was longer in gallstone patients than in healthy subjects (158.2 +/- 17.0 vs 105.5 +/- 10.4 min, respectively; P < 0.05), due to longer phase I (39.8 +/- 5.7 vs 17.2 +/- 3.7 min, respectively; P < 0.05). In contrast to healthy subjects, gallstone patients had no significant fluctuations of gallbladder volume during the MMC cycle, and motilin concentrations were not different in MMC cycles with phase III originating in antrum or duodenum. During MMC cycles with phase III originating in the duodenum, motilin levels were twice as high in gallstone patients as in healthy subjects (P < 0.002). In conclusion, cholesterol gallstone patients have an abnormal MMC and motilin release pattern. Their interdigestive gallbladder emptying is reduced and dissociated from the MMC. These disturbances may contribute to gallstone formation.
Severe impairment of postprandial cholecystokinin release and gall-bladder emptying and high risk of gallstone formation in acromegalic patients during Sandostatin LAR.
BACKGROUND: Acromegalic patients treated three times daily with subcutaneous injections of the somatostatin analogue octreotide frequently develop gallstones, due to suppressed cholecystokinin release and impaired gall-bladder emptying. AIM: To elucidate the effects of a new long-acting octreotide formulation (Sandostatin LAR) on gall-bladder emptying, cholecystokinin release and gallstone formation. METHODS: Postprandial gall-bladder and gastric emptying were determined by ultrasonography and cholecystokinin release was measured in seven patients on days 0, 14, 28, and 75 (Sandostatin LAR, 20 mg intramuscularly on days 1, 30, and 60). RESULTS: During treatment, fasting gall-bladder volumes increased from 26.5 +/- 3.2 mL to 61.4 +/- 7.5 mL, but postprandial cholecystokinin release and gall-bladder emptying (from 63.9 +/- 3.8% to 12.3 +/- 3.5%) were severely suppressed. Gallstones formed in six out of seven patients within 8 months of treatment. Gastric emptying did not change during the therapy. CONCLUSIONS: The risk of gallstone formation is greatly increased during Sandostatin LAR. This is probably related to profound suppression of cholecystokinin release and gall-bladder emptying.
Hodgkin's disease presenting as a parasternal chest wall mass.
A 53 year-old Moroccan woman presented with a tender parasternal mass. Computerized tomography showed a mediastinal mass protruding through the sternum. Cytologic examination of fluid collected from the mass repeatedly showed acute inflammation. Tuberculostatics were started. Since patient did not improve on tuberculostatics, a small supraclavicular lymph node was removed. Histologic examination showed Morbus Hodgkin of the nodular sclerosing type. Ultimately, cytologic examination of fluid from the parasternal mass showed atypical cells. Response on chemotherapy was excellent with complete disappearance of the parasternal mass. This is a very unusual extranodal presentation of Hodgkin's disease.
Motilin induces gall bladder emptying and antral contractions in the fasted state in humans.
BACKGROUND: Animal studies have shown that motilin affects gall bladder motility. In humans, no effect has been shown, but erythromycin, a motilin receptor agonist, induces gall bladder emptying. AIMS: To explore the effect of increasing doses of exogenous motilin on gall bladder volume and antral contractility in the fasted state in humans. METHODS: After an overnight fast, eight healthy men received increasing intravenous doses of Leu13-motilin (KW-5139) or 0.9% NaCl in a double blind, randomised fashion. Gall bladder volume and antral contraction frequency were determined by ultrasonography. RESULTS: Infusion of motilin increased plasma motilin levels. Motilin induced a reduction in gall bladder volume of 8.0 (5.0)%, 17.1 (5.0)%, 18.5 (4.7)%, and 16.1 (4.9)% of baseline volume at the end of infusion of 2, 4, 8, and 16 pmol/kg/min respectively, compared with mean stable gall bladder volumes during placebo infusion (p < 0.05). Antral contraction frequency increased during motilin infusion, but not during placebo infusion (p < 0.05). CONCLUSIONS: Exogenous motilin reducted fasting gall bladder volume and increased antral contractions. After reaching maximal reduction, the gall bladder volume did not decrease further during continuous motilin infusion at higher doses and stayed at the same reduced volume. The degree of gall bladder volume reduction during motilin infusion mimicked gall bladder emptying preceding antral phase III activity of the migrating motor complex in humans. This study indicates that motilin may play a physiological role in the regulation of gall bladder emptying in the fasted state.
Symptomatic gallbladder stones. Cost-effectiveness of treatment with extracorporeal shock-wave lithotripsy, conventional and laparoscopic cholecystectomy.
In order to strike the most favorable balance between health benefits and costs, three treatment modalities for symptomatic cholelithiasis were compared in a cost-effectiveness study: extracorporeal shock-wave lithotripsy (ESWL), conventional cholecystectomy (CC), and laparoscopic cholecystectomy (LC). Data were analyzed from 55 patients who were treated by ESWL, 45 patients who had CC, and 47 patients who had LC. The study was performed by analysis of patients charts and a written questionnaire. After ESWL 35% of the patients were free of stones, 23% had fragments < or = 5 mm, and 42% had fragments > 5 mm at 1-year follow-up. Persistent complaints were reported by 59% after ESWL, 11% after CC, and 14% after LC (P < 0.001). New complaints arose in 12% after ESWL, 11% after CC, and in 5% after LC (P = NS). Patient appreciation score was highest for LC and lowest for ESWL. Mean hospital stay was 2.4 days for ESWL, 10 days for CC, and 3.5 days for LC. Overall costs of treatment were: $5,066 for ESWL; $5,893 for CC; and $3,117 for LC. This study reveals that laparoscopic cholecystectomy is the most effective treatment of the large majority of patients with symptomatic cholelithiasis. ESWL should only be considered in the case of a solitary, relatively small, completely radiolucent stone.
Gallbladder emptying in vivo, bile composition, and nucleation of cholesterol crystals in patients with cholesterol gallstones.
BACKGROUND/AIMS: Impaired postprandial gallbladder emptying may provide time for progressive bile concentration with formation of instable cholesterol-rich vesicles and fast nucleation of cholesterol crystals. The aim of this study was to assess postprandial gallbladder emptying, bile composition, and nucleation of cholesterol crystals in the same patient. METHODS: In 30 patients with cholesterol gallstones, postprandial gallbladder emptying was measured ultrasonographically. In each patient, gallbladder bile composition (obtained at cholecystectomy) and nucleation of cholesterol crystals was determined. Patients were divided in 22 strong contractors (> 50% postprandial gallbladder emptying) and 8 weak contractors. RESULTS: In weak contractors, bile salt and phospholipid concentrations were much higher than in strong contractors (234.6 +/- 24.7 vs. 130.3 +/- 10.8 mmol/L [P < 0.001] and 44.5 +/- 3.5 vs. 30.2 +/- 3.1 mmol/L [P < 0.05], respectively). Cholesterol concentrations were comparable in strong and weak contractors. Consequently, total lipid concentration was significantly higher (15.5 +/- 1.4 and 9.2 +/- 0.7 g/dL; P < 0.001) and cholesterol saturation index significantly lower (0.90 +/- 0.08 and 1.61 +/- 0.17; P < 0.001) in weak contractors. Nucleation time, percentage of cholesterol in vesicles, bile salt species, and molecular species of phosphatidylcholine were not significantly different. CONCLUSION: Differences in bile composition can be linked to different patterns of postprandial gallbladder emptying and may point to two different pathways of gallstone formation.
Effect of octreotide on fasting gall bladder emptying, antroduodenal motility, and motilin release in acromegaly.
Subcutaneous octreotide (Sandostatin) injections lead to gall stone formation in 13-50% of acromegaly patients during one year of therapy. This study explored the effects of octreotide on interdigestive gall bladder emptying, antroduodenal motility, and motilin release. Ambulatory antroduodenal manometry was performed in six acromegaly patients before and after two months of octreotide therapy (100 micrograms thrice daily, subcutaneously). Ultrasonographic gall bladder volume measurements and plasma motilin concentrations were obtained during two migrating motor complex (MMC) cycles. Before octreotide treatment, nine of 26 phase III activities started in the antrum and 17 of 26 in the duodenum whereas during treatment 47 of 48 of phase III activity started in the duodenum (p < 0.05). Before treatment, interdigestive gall bladder emptying (mean (SEM) 39.9 (4.0)% of maximal fasting volume) and plasma motilin peaks preceded antral phase III but not duodenal phase III. During octreotide therapy no significant motilin fluctuation or gall bladder emptying was seen. Fasting gall bladder volume increased from 40.9 (9.1) ml before to 68.0 (14.8) ml (p < 0.05) during octreotide treatment. In conclusion, two months' treatment with octreotide increases the number of duodenal phase III like activity and virtually abolishes antral phase III, plasma motilin peaks, and interdigestive gall bladder emptying. These effects might contribute to the high risk of gall stone formation during longterm octreotide treatment.
Cholesterol gallstone formation in man and potential treatments of the gallbladder motility defect.
Cholelithiasis affects 10-15% of the adult population in Western society, and about 75% of gallstones are of cholesterol type. Hepatic hypersecretion of cholesterol with the formation of instable cholesterol-rich vesicles in bile, an imbalance between nucleation-inhibiting and nucleation-promoting proteins with further aggregation of cholesterol crystals in a gallbladder with a motility defect (stasis), all play a role in the pathogenesis of cholesterol gallstones. Experimental animal models suggest that gallstone formation can be prevented by improving gallbladder emptying. Thus, a better understanding of the causes underlying the impaired gallbladder motor function in patients with gallstones might lead to the selection of therapeutic approaches for those individuals who are at increased risk for the formation or recurrence of gallstones. The present article focuses on current concepts and theories on the pathogenesis of cholesterol gallstones with emphasis on the gallbladder motility defect. Several treatment strategies for the correction of gallbladder hypomotility are also discussed.
The effects of the 3-hydroxy, 3-methylglutaryl coenzyme A reductase inhibitor pravastatin on bile composition and nucleation of cholesterol crystals in cholesterol gallstone disease.
3-hydroxy,3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors reduce biliary cholesterol saturation index (CSI) in duodenal bile in hypercholesterolemic patients and might be useful for gallstone dissolution. However, preliminary data suggest that these drugs are not effective in this respect. We therefore studied 33 patients with radiolucent gallstones in an opacifying gallbladder who were scheduled for elective cholecystectomy. Patients were treated with 40 mg pravastatin day-1 or placebo during the 3 weeks before surgery. Six patients could not be evaluated. Baseline characteristics (age, sex, body mass index, serum cholesterol, and the solitary/multiple gallstone ratio) were similar in both groups. Serum cholesterol fell by 39% in the pravastatin group (P < .001) and remained unchanged in the placebo group. Biliary cholesterol (9.5 +/- 1.3 vs. 14.3 +/- 1.5 mmol/L, P = .026), and phospholipid concentrations (24.8 +/- 3.9 vs. 36.7 +/- 3.9 mmol/L, P = .043) were lower in the pravastatin group. Although bile salt concentrations were lower in the pravastatin group (114 +/- 21 vs. 152 +/- 15 mmol/L), this difference was not significant. CSI was not different between both groups (142 +/- 27% [pravastatin] vs. 113 +/- 6% [placebo], P = NS). Cholesterol crystals were present in fresh bile in 7 of 13 patients in the pravastatin group and in 11 of 14 controls (P = NS). Nucleation time was comparable between the 2 groups (13 +/- 3 vs. 9 +/- 3 days, P = NS). Bile salt species and molecular species of phospholipids determined with high-performance liquid chromatography did not differ either between both groups.(ABSTRACT TRUNCATED AT 250 WORDS)
The effects of bile salt hydrophobicity on model bile vesicle morphology.
The addition of bile salts to vesicles supersaturated with cholesterol induces cholesterol precipitation, an important step in the formation of cholesterol gallstones. To investigate the effects of bile salt hydrophobicity on vesicle morphology, vesicles obtained from supersaturated model bile by density gradient ultracentrifugation, were incubated with mixtures of deoxycholate (DC) and ursodeoxycholate (UDC) with a constant total bile salt concentration of 30 mM but with a varying hydrophobicity index ranging from -0.31 (UDC alone) up to +0.72 (DC alone) depending on the composition of the mixture. Five days after addition of bile salts to vesicles, cholesterol precipitation was determined microscopically and incubation samples were again subjected to ultracentrifugation to assess the lipid distribution among residual vesicles, mixed micelles, and cholesterol crystals. Structure and size of the isolated residual vesicles were studied by freeze fracture electron microscopy. The control, and samples exposed to hydrophilic bile salt mixtures, consisted of unilamellar vesicles of which more than 75% had a diameter of 50-80 nm. After addition of increasingly hydrophobic bile salt mixtures, multilamellar vesicles with progressively greater diameters (up to 1300 nm) were found, suggesting that vesicle fusion and aggregation took place and might hence be important in the cholesterol precipitation process. Accordingly, crystallization was positively correlated with bile salt hydrophobicity. We conclude that cholesterol crystallization from vesicles depends on the hydrophobicity of the bile salts added, and apparently occurs from fused or aggregated vesicles of extended magnitude and with a multilamellar constitution.
The effect of bile acid hydrophobicity on nucleation of several types of cholesterol crystals from model bile vesicles.
Nucleation of cholesterol crystals is thought to occur from cholesterol-phospholipid vesicles. We tested the hypothesis that bile acids are necessary for nucleation of cholesterol crystals. Model bile vesicles were prepared by KBr density ultracentrifugation of supersaturated model bile and mixed with one of the following bile acids: ursodeoxycholate, taurocholate, cholate, chenodeoxycholate or deoxycholate in final concentrations of 3, 30 and 100 mM. Vesicles were also mixed with various combinations of ursodeoxycholate and deoxycholate. Nucleation was assessed semi-quantitatively with polarizing microscopy. After 5 days, samples were again subjected to ultracentrifugation. Addition of 3 and 30 mM taurocholate, cholate, chenodeoxycholate and deoxycholate to vesicles induced nucleation. The extent of nucleation increased significantly with increasing bile acid hydrophobicity: deoxycholate > chenodeoxycholate > cholate > taurocholate (p < 0.05). At 100 mM bile acid this order was reversed (p < 0.05) because most of the cholesterol was solubilized in micelles as shown by ultracentrifugation after 5 days. Percentages of vesicular cholesterol decreased with increasing hydrophobicity: deoxycholate < chenodeoxycholate < cholate < taurocholate (p < 0.05). Ursodeoxycholate did not induce nucleation. At least seven cholesterol crystal shapes could be distinguished and all crystal types could be found after addition of various combinations of ursodeoxycholate+deoxycholate. We conclude that in this model: (a) bile acid species play an important role in the precipitation of cholesterol crystals from model bile vesicles; (b) the more hydrophobic bile acids induce more cholesterol crystal precipitation; and (c) the hydrophobicity of bile acids influences cholesterol crystal morphology.
Effects of bile salt and phospholipid hydrophobicity on lithogenicity of human gallbladder bile.
Increased biliary bile salt and phospholipid hydrophobicity may promote nucleation of cholesterol crystals and gallstone formation. We therefore compared bile salt composition (determined by gas-liquid chromatography) in patients with cholesterol (n = 35) and pigment (n = 16) gallstones (group A). Bile salt composition and cumulative bile salt hydrophobicity index were not different between both stone types. Hydrophobicity index or % of individual bile salts did not correlate with cholesterol saturation index or nucleation time. In an additional 21 cholesterol stone patients (group B) biliary bile salt and phospholipid hydrophobicity as determined by high-pressure liquid chromatography did not correlate with cholesterol saturation index or nucleation time. In both group A and group B, cholesterol stone patients with cholesterol crystals in their fresh biles had a higher % deoxycholic acid, a lower % cholic acid and a higher bile salt hydrophobicity index than crystal-negative patients. This study indicates the need for further research on the role of bile salt hydrophobicity in the pathogenesis of gallstones.
Gallbladder motility and cholecystokinin release during long-term enteral nutrition in patients with Crohn's disease.
BACKGROUND: Gallbladder bile stasis during long-term continuous enteral feeding may contribute to the high prevalence of gallstones in patients with Crohn's disease. We therefore examined the effects of continuous enteral nutrition on gallbladder motility and cholecystokinin (CCK) release in six patients. METHODS: Gallbladder volume was measured ultrasonographically for 12 h on days 1 (start), 8, 22 (6-h interruption of enteral feeding), 36, and 43 (end) of enteral feeding. Plasma CCK was assessed at several time points. RESULTS: Initial fasting gallbladder volume was 19.3 +/- 4.5 (mean +/- SEM) ml, which decreased to 4.9 +/- 3.6 ml after start of feeding. CCK increased from 1.5 +/- 0.3 to 3.9 +/- 1.1 pmol/l. On days 8 and 36 the gallbladder was almost completely contracted, and CCK increased to 7.5 +/- 2.7 and 8.3 +/- 2.6 pmol/l, respectively. On days 22 and 43 gallbladder volume increased, and CCK decreased rapidly to fasting concentrations after interruption of feeding. CONCLUSIONS: During continuous enteral nutrition the gallbladder is completely contracted, and CCK concentrations remain elevated. It is therefore unlikely that long-term enteral nutrition contributes to the increased prevalence of gallstones in patients with Crohn's disease.
Bile salt-induced cholesterol crystal formation from model bile vesicles: a time course study.
Precipitation of cholesterol crystals from vesicles is an important step in the pathogenesis of cholesterol gallstones. Little is known, however, about the kinetics and the mechanisms involved in cholesterol crystallization. Therefore, the time course of cholesterol crystal precipitation and lipid exchange between vesicles and micelles were monitored in a model bile system. Vesicles obtained from supersaturated model bile (cholesterol saturation index (CSI) 1.4; 10 g/dl) by KBr density gradient ultracentrifugation, were incubated with various bile salts: deoxycholate (DC), chenodeoxycholate (CDC), cholate (C), ursodeoxycholate (UDC), and their respective taurine and glycine conjugates. Vesicle integrity was assessed in a leakage-assay of carboxyfluorescein-loaded vesicles (0-15 min) and by the change in optical absorbance at 340 nm of a vesicle solution (0-50 min). Fluorescence increased within 1 min after addition of bile salt, and was stable within 5-10 min. After addition of bile salt, absorbance fell immediately and stabilized within 30 min. Fluorescence and absorbance were dependent on bile salt hydrophobicity and concentration. At several time points after addition of bile salt to vesicles (from 1 to 72 h), the extent of cholesterol nucleation was determined semiquantitatively and incubation mixtures were again subjected to ultracentrifugation to assess the lipid distribution among residual vesicles, de novo formed mixed micelles, and cholesterol crystals. Nucleation occurred within 0.5 h after exposure of vesicles to the hydrophobic bile salts DC or CDC, and the cholesterol/phospholipid (c/p) ratio of the vesicles showed a transient rise from 1.45 to 3-4 (at t = 0.5 h) that coincided with the appearance of mixed micelles. Then the vesicular c/p ratio decreased to 0.6-0.8 (at t = 24 h) concomitantly with increasing precipitation of cholesterol crystals. In the case of UDC, the most hydrophilic bile salt used, < 5% micellization, no nucleation, and a constant vesicular c/p ratio were observed. We conclude that under the conditions used in the present model study, the kinetics of cholesterol crystallization are governed by the hydrophobicity of the added bile salts and their capacity to form mixed micelles. The results emphasize the pivotal role of time, and the dynamic aspects of the processes involved in cholesterol crystal formation.
Bile concentration promotes nucleation of cholesterol monohydrate crystals by increasing the cholesterol concentration in the vesicles.
Cholesterol in bile is solubilized in mixed micelles and cholesterol-phospholipid vesicles. Biliary cholesterol supersaturation and increased concentration of bile in the gallbladder promotes nucleation of cholesterol monohydrate crystals and gallstone formation, possibly by creating unstable vesicles with a high cholesterol/phospholipid ratio. In the present study super-saturated and unsaturated biles (cholesterol saturation index (CSI) 1.4 and 0.8 respectively) were prepared with concentrations typical of gallbladder and more dilute hepatic bile (total lipid concentration (TLCo) 10 and 2.5 g dl-1 respectively). The distribution of cholesterol between vesicles and micelles, and vesicular cholesterol/phospholipid ratio were studied using ultracentrifugation and gel-permeation chromatography. The nucleation time of cholesterol crystals was determined in whole model bile, and in the vesicular and micellar peak fractions. Increased CSI and bile dilution led to an increased proportion of cholesterol solubilized in vesicles. The concentration of bile did not influence vesicular cholesterol/phospholipid ratio. The vesicular cholesterol/phospholipid ratio found in gel-permeation chromatography experiments was similar at high and low CSI, whereas the ratio was significantly higher in supersaturated than in unsaturated biles in ultracentrifugation studies. Nucleation of cholesterol crystals from whole model bile was more rapid at the higher bile concentration and higher cholesterol saturation. Nucleation time in whole model bile correlated significantly with nucleation time in the corresponding vesicular peak fraction obtained by gel-permeation chromatography (r = 0.58: P < 0.01) and with the cholesterol concentration in this vesicular peak (r = -0.77; P < 0.002) but not with vesicular peak cholesterol/phospholipid ratio.(ABSTRACT TRUNCATED AT 250 WORDS)
Postprandial gall bladder motility and hormone release during intermittent and continuous subcutaneous octreotide treatment in acromegaly.
Repeated daily injections of the somatostatin analogue, octreotide (SMS201-995, Sandostatin) are an effective treatment for acromegaly, but lead to gall stone formation in about 50% of cases during longterm treatment. This is probably because of impaired gall bladder contraction. This study examined whether the timing of intermittent injections in relation to meals, or alternatively, continuous 24 hour subcutaneous octreotide infusion (CSOI) might avert adverse effects on gall bladder contraction. In six patients with active acromegaly, gall bladder volume, plasma cholecystokinin (CCK), and pancreatic polypeptide (PP) were measured in the fasting state and after consumption of a fatty meal. Measurements were made on five separate days: (a) without treatment, (b) 45 minutes after 100 micrograms octreotide given subcutaneously, (c) four hours after 100 micrograms octreotide given subcutaneously, (d) eight hours after 100 micrograms octreotide given subcutaneously, and (e) during CSOI of 300 micrograms/24 h for two weeks. Without treatment, postprandial gall bladder contraction was 86.2 (2.1%). Fasting gall bladder volume increased after octreotide injection and was almost doubled during CSOI. Octreotide injections impaired postprandial gall bladder contraction as well as CCK and PP release for at least four hours. Eight hours after injection and during CSOI, postprandial gall bladder contraction was partly restored (43.4% and 50.8% respectively). Postprandial CCK release was normal at eight hours after injection but very low during CSOI. PP release was suppressed by each mode of octreotide treatment. This study indicates that octreotide injections impair postprandial gall bladder contraction for at least four hours. Eight hours after injection and during CSOI, gall bladder contraction is partly restored.