Design optimization and characterization of Her2/neu-targeted immunotoxins: comparative in vitro and in vivo efficacy studies

Targeted therapeutics are potential therapeutic agents because of their selectivity and efficacy against tumors resistant to conventional therapy. The goal of this study was to determine the comparative activity of monovalent, engineered anti-Her2/neu immunotoxins fused to recombinant gelonin (rGel) to the activity of bivalent IgG-containing immunoconjugates. Utilizing Herceptin and its derived humanized single-chain antibody (single-chain fragment variable, designated 4D5), we generated bivalent chemical Herceptin/rGel conjugate, and the corresponding monovalent recombinant immunotoxins in two orientations, 4D5/rGel and rGel/4D5. All the constructs showed similar affinity to Her2/neu-overexpressing cancer cells, but significantly different antitumor activities. The rGel/4D5 orientation construct and Herceptin/rGel conjugate were superior to 4D5/rGel construct in in vitro and in vivo efficacy. The enhanced activity was attributed to improved intracellular toxin uptake into target cells and efficient downregulation of Her2/neu-related signaling pathways. The Her2/neu-targeted immunotoxins effectively targeted cells with Her2/neu expression level >1.5 × 10(5) sites per cell. Cells resistant to Herceptin or chemotherapeutic agents were not cross-resistant to rGel-based immunotoxins. Against SK-OV-3 tumor xenografts, the rGel/4D5 construct with excellent tumor penetration showed impressive tumor inhibition. Although Herceptin/rGel conjugate demonstrated comparatively longer serum half-life, the in vivo efficacy of the conjugate was similar to the rGel/4D5 fusion. These comparative studies demonstrate that the monovalent, engineered rGel/4D5 construct displayed comparable in vitro and in vivo antitumor efficacy as bivalent Herceptin/rGel conjugate. Immunotoxin orientation can significantly impact the overall functionality and performance of these agents. The recombinant rGel/4D5 construct with excellent tumor penetration and rapid blood clearance may reduce the unwanted toxicity when administrating to patients, and warrants consideration for further clinical evaluation.

Estrogen replacement therapy and gallbladder disease in postmenopausal women

OBJECTIVE

To examine the role of estrogen replacement therapy on the development of gallbladder disease in postmenopausal women.

DESIGN

Systematic review of the English literature was conducted. All studies that addressed the association between hormone replacement therapy and gallbladder disease published from 1970 to the present were reviewed.

RESULTS

Seven observational studies, two clinical trials, two case series, and one nonrandomized and three randomized investigations were reviewed. The results of each study were reported and analyzed.

CONCLUSIONS

Estrogen replacement therapy in postmenopausal women increased the chances for gallstone formation.

Comparative cytotoxicity and pharmacokinetics of antimelanoma immunotoxins containing either natural or recombinant gelonin

Immunotoxins are a class of targeted therapeutic agents under development by various research groups. The murine monoclonal antibody designated ZME-018 recognizes a high molecular weight glycoprotein present on most human melanoma cells and biopsy specimens and has been utilized for clinical imaging studies in patients with melanoma. The plant toxin gelonin is a ribosome-inactivating protein (RIP) with n-glycosidase activity similar to that of ricin A chain. In previous studies by our group, the gelonin toxin was sequenced, cloned and expressed in E. coli. The purified recombinant gelonin (RG) was found to have identical protein synthesis inhibitory activity to that of natural gelonin (NG). For comparative purposes, chemical conjugates of antibody ZME and either RG or NG were produced using the heterobifunctional crosslinking reagents SPDP and SMPT. The ZME-NG and ZME-RG immunotoxins were found to be 10(4)- to 10(5)-fold more cytotoxic to antigen-positive human melanoma cells than free toxin. NG toxin alone was cytotoxic to intact cells (IC(50) = 100 nM) while RG was nontoxic to cells at doses up to 1 microM. Both ZME-NG and ZME-RG immunoconjugates were nontoxic to antigen-negative (Me-180) cells. ZME-RG immunotoxins constructed with the more stable SMPT reagent were slightly more effective in culture than conjugates made with SPDP. Tissue distribution studies in tumor-bearing nude mice demonstrated that tumor uptake of the ZME-RG immunotoxin was similar to that of the intact ZME antibody with reduced distribution to normal organs compared to an immunoconjugate produced with NG. Pharmacokinetic studies showed that the terminal-phase plasma half-life of ZME-RG was similar to that of ZME itself (42 h vs 50 h) and almost threefold higher than that of ZME-NG (11.5 h). The area under the concentration curve (Cxt) for ZME-RG was 50% lower than that for ZME due to an increased apparent volume of distribution (Vd(a)) but was almost tenfold higher than the Cxt for ZME-NG. These studies suggest that immunoconjugates comprising RG demonstrate identical in vitro cytotoxic effects to immunoconjugates produced with NG and immunotoxins with RG display improved in vivo pharmacodynamics and tissue distribution compared to immunotoxins containing NG.

Recombinant immunotoxins directed against the c-erb-2/HER2/neu oncogene product: in vitro cytotoxicity, pharmacokinetics, and in vivo efficacy studies in xenograft models

TAB-250 and BACH-250 are murine and human chimeric antibodies directed at the extracellular domain of the gp185c-erb-2 (HER2/neu) growth factor receptor overexpressed in a variety of tumor types, including ovarian and breast carcinoma. The ribosome-inhibiting plant toxin gelonin (rGel) was chemically coupled to both antibodies, and the resulting immunotoxins were purified and tested in vitro against human tumor cells expressing various levels of HER-2/neu and in vivo against human tumor xenograft models. The binding of both BACH-250 and BACH-250/rGel conjugate to target cells was essentially equivalent. Against SKOV-3 cells, the IC50 of BACH-250/rGel was 97 pM (17 ng/ml), whereas BACH-250 and rGel alone showed no cytotoxic effects. There was a clear correlation between expression levels of HER-2/neu and cytoimmunotoxin. Tissue distribution studies showed that the antibody and immunotoxin both concentrate 2-10-fold higher in tumors than in normal tissues, with optimal tumor uptake occurring 48-96 h after administration. Plasma clearance curves for BACH-250 and BACH-250/rGel showed terminal-phase half-lives of 26 and 72 h, respectively. In athymic mice bearing s.c. or i.p. SKOV-3 tumors, immunotoxin treatment slowed tumor growth by 99 and 94 % at days 35 and 49 after implantation, respectively, and lengthened the median survival by 40% (from 30 to 50 days) in mice bearing lethal i.p. tumors. We conclude that clinical development of BACH-250/rGel may be warranted in patients with HER2/neu-expressing malignancies.

Comparison of the impact of transdermal versus oral estrogens on biliary markers of gallstone formation in postmenopausal women

This prospective, randomized, double blind, parallel study was undertaken to elucidate further the potential mechanisms through which estrogens could promote the formation of cholesterol gallstones and to compare the impact of nonoral (transdermal) and oral estrogens on serum, hepatic, and biliary markers of estrogen action. Ninety-seven postmenopausal women were randomized to receive either transdermal estradiol (E2; 0.1 mg every 3.5 days; n = 48) or oral conjugated equine estrogens (1.25 mg every day; n = 49) for 8 weeks. Blood samples were drawn, and bile samples were obtained by cholecystokinin-stimulated duodenal drainage before and after 8 weeks of estrogen administration. The main outcome measures included serum FSH, LH, E2, estrone, estrone sulfate, sex hormone-binding globulin, lipid profiles, biliary cholesterol saturation index, cholesterol nucleation time, presence of cholesterol crystals in bile, as well as biliary arachidonate, PGE2, and mucous glycoproteins. Estrogens administered by both routes increased circulating estrogens and resulted in similar suppression of both gonadotropins. Sex hormone-binding globulin was clearly increased, and the changes in serum lipids were more pronounced with oral conjugated equine estrogens than with transdermal E2. The biliary cholesterol saturation index was significantly increased compared to the baseline values with both transdermal E2 (1.08 +/- 0.04 vs. 1.00 +/- 0.03; mean change, 8%) and oral conjugated equine estrogens (1.04 +/- 0.03 vs. 0.99 +/- 0.03; mean change, 6%); however, there was no difference between the treatments. The number of patients with cholesterol crystals detected in bile was similar after both estrogen regimens. Transdermal and oral estrogens decreased nucleation time in vitro, increased arachidonate and PGE2 levels, and minimally raised total glycoprotein concentrations. In conclusion, transdermal and oral estrogens exerted comparable nonhepatic effects, as evidenced by similar reductions of gonadotropin levels, but oral therapy exhibited substantially greater actions on hepatic markers of estrogen action. Both transdermal E2 and oral conjugated equine estrogens significantly elevated the biliary cholesterol saturation index and reduced the nucleation time. These results suggest that estrogens at the doses studied could promote gallstone formation by alteration of biliary lipids and cholesterol nucleation time that have been incriminated in this process.

High-dose preoperative radiation and the challenge of sphincter-preservation surgery for cancer of the distal 2 cm of the rectum

PURPOSE

Sphincter-preserving surgery for the management of distal rectal cancer is gaining recognition as an alternative to abdominoperineal resection and loss of anal function. The use of high-dose preoperative radiation appears to enhance the options for sphincter preservation, even in the most distal segments of the rectum.

MATERIALS AND METHODS

Seventy patients with tumors located in the distal 2 cm of the rectum received a minimum dose of 40 to 45 Gy over 4 1/2 weeks at 1.8 to 2.5 Gy per fraction. Patients with unfavorable tumors were given an additional boost of 10 to 15 Gy. Surgery was performed 5 to 10 weeks following completion of radiation. Radical surgical resection was performed in 48 patients and full thickness local excision in 22. Follow-up ranged from a minimum of 1 year to a maximum of 10 years, with a median of 4 years.

RESULTS

There was one perioperative mortality. Two patients did not have their colostomy closed because of complications. Late diversion was required in 4 patients, primarily for recurrent disease. Sixty patients (86%) maintained long-term satisfactory sphincter function. Local recurrence was observed in 9 patients (13%) and distant metastases in 12 patients (17%). The overall five-year actuarial survival rate was 82%. The 5-year survival and local recurrence for postradiation pathological stage of disease was: T0, T1, T2, N0--95% and 8%, T3, T4, N0--91% and 4%, T(any) N+--50% and 41%, respectively.

CONCLUSION

High-dose preoperative radiation, in properly selected patients with rectal cancers of the distal 2 cm, offers opportunities for sphincter-preserving surgical resection with excellent local control, survival, and enhanced quality of life.

Nucleation of biliary cholesterol, arachidonate, prostaglandin E2, and glycoproteins in postmenopausal women

BACKGROUND & AIMS

Among dieting obese patients, cholesterol gallstone formation is preceded by increases in levels of biliary cholesterol saturation, arachidonate, prostaglandin E2, total glycoproteins, and rapid nucleation of cholesterol. The aim of this study was to determine if similar increases occur among postmenopausal women with cholesterol crystals in their bile.

METHODS

In 101 postmenopausal women without gallstones, gallbladder bile was sampled via nasoduodenal tube and analyzed.

RESULTS

Nineteen of the women had saturated bile and crystals. Levels of cholesterol saturation, arachidonate, prostaglandin E2, and total glycoprotein were highest among women with cholesterol-saturated bile and cholesterol crystals and lowest among women with unsaturated bile. Levels were intermediate among women with saturated bile but no crystals.

CONCLUSIONS

Among postmenopausal women, increases in levels of biliary cholesterol saturation, arachidonate, prostaglandin E2, and total glycoproteins may be important pathophysiologically in the rapid nucleation of cholesterol crystals.

Effects of ursodiol or ibuprofen on contraction of gallbladder and bile among obese patients during weight loss

Rapid loss of weight in obese patients is associated with increased saturation of bile with cholesterol, increased nucleation and growth of cholesterol crystals, and gallstones. The aims of this study were to determine the effects of rapid weight loss on contraction of the gallbladder and to evaluate the effects of ursodiol and ibuprofen on saturation, nucleation and growth, and contraction. Forty-seven obese patients entering a very low calorie dietary program were randomized to receive ursodiol, 1200 mg/day, ibuprofen, 1600 mg/day, or placebo for 12 weeks. Contraction of the gallbladder to a liquid meal was evaluated by ultrasonography, and duodenal bile was collected initially and after six and 12 weeks. Diet caused reduced contraction of the gallbladder, increased cholesterol saturation, and increased nucleation and growth of crystals. Ursodiol reduced saturation and prevented increases in nucleation and growth and contraction. Ibuprofen prevented the increase in saturation and the reduction in contraction with a trend opposing the increase in nucleation and growth. In conclusion, during dieting, contractility of the gallbladder to meals is reduced. The effectiveness of ursodiol in preventing gallstones may be explained partially by effects on contraction. Ibuprofen deserves further study because of its effects on saturation, nucleation and growth, and contraction.

Natural history and treatment with ursodiol of gallstones formed during rapid loss of weight in man

Cholesterol gallstones form frequently among obese patients during rapid loss of weight. The aims of the present study were to determine the short-term natural history of these gallstones and the efficacy of ursodiol for their dissolution. Twenty-two patients whose gallstones had formed during rapid loss of weight were randomized in double-masked fashion to either ursodiol, 1200 mg/day, or placebo for nine months. Ultrasonography of the gallbladder was performed after three and nine months of treatment. All patients without disappearance of their gallstones after nine months received open-label ursodiol for an additional nine months with ultrasonography after three and nine months. Among the patients completing three months of masked treatment, disappearance of gallstones was seen in five of 11 patients who received placebo and four of seven patients who received ursodiol. Only one additional patient of six continuing placebo for nine months experienced disappearance. Neither of two patients continuing ursodiol for nine months had disappearance of gallstones. None of the five patients treated with open-label ursodiol for nine months had disappearance of gallstones. Thus, half of the gallstones that form during rapid loss of weight disappear rapidly once loss of weight ceases; ursodiol may not increase the frequency or rapidity of their disappearance.

Oral and contact dissolution of gallstones

The appropriate selection of patients for treatment with oral ursodeoxycholic acid (UDCA)--a drug that has virtually no side effects--results in about 50% of patients experiencing safe dissolution of gallstones within 2 years. Eligible patients have small (less than 20 mm in diameter) radiolucent gallstones in a gallbladder visualized by oral cholecystography (OCG); ideal candidates are thin women who have gallstones that are less than 15 mm in diameter, floating when observed by OCG, or of low density on computed tomographic (CT) scanning. Contact dissolution with methyl tert-butyl ether (MTBE) is rapid, effective more often than UDCA, and safe but requires the expertise of an interventional radiologist. Any size and number of cholesterol gallstones that are not CT-dense will be dissolved by MTBE, leaving at most only insoluble debris that is clinically innocuous. Although gallstones recur after dissolution by UDCA or MTBE in 50% of patients within 5 years, recurrent gallstones are usually asymptomatic and/or can probably be dissolved. We conclude that oral or contact dissolution provides an alternative treatment to cholecystectomy for about 30% of patients with symptomatic gallstones.

A gelonin-containing immunotoxin directed against human breast carcinoma

Toxins may be specifically directed to tumor cells and the toxins' potency greatly increased by covalent conjugation to monoclonal antibodies recognizing tumor-associated antigens. Antibody 15A8, an immunoglobulin G1 (IgG1) subclass anti-human breast carcinoma murine monoclonal antibody and gelonin, a plant toxin, were covalently modified with N-succimindyl 3-(2-pyridyldithio) proprionate and iminothiolane, respectively, and allowed to cross-link. 15A8-gelonin conjugates were purified from unreacted antibody and free gelonin by gel filtration and blue sepharose chromatography. Analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that the final product contained two bands corresponding to antibody:gelonin conjugates of 1:1 (predominant) and 1:2. There were no contaminating amounts of free antibody or free toxin in the preparation. The yield of the final purified 15A8-gelonin conjugate was approximately 20% based on the amount of starting antibody. The protein synthesis inhibitory activity of the immunoconjugate was assessed by in vitro rabbit reticulocyte translation assay. This functional activity was normalized to that of unmodified gelonin for use in in vitro antiproliferative assays against antigen-negative (Hs294t human melanoma) and antigen-positive (ME-180 human cervical carcinoma) cell lines. Antigen-negative Hs294t cells incubated for 72 hours with 15A8-gelonin immunotoxin showed no increased cytotoxicity compared with HS294t cells exposed to free gelonin alone. However, the immunotoxin was preferentially toxic to antigen-positive ME-180 cells; over 5 logs greater cell kill was observed after 72 hours exposure to 15A8-gelonin than after the same exposure to gelonin alone. Various lysosomotropic agents augmented 15A8-gelonin cytotoxicity; the most effective potentiating agent appeared to be monensin. In addition, the chemotherapeutic agents L-phenylalanine mustard (L-PAM), 5-fluorouracil, vincristine, and bleomycin, and the biological response modifiers interferon-alpha and tumor necrosis factor-alpha were shown to augment 15A8-gelonin cytotoxicity. Should in vivo pharmacology and therapeutic studies confirm these in vitro findings, 15A8-gelonin conjugate may be a potent agent for therapy of cancer in man.

The sequence of biliary events preceding the formation of gallstones in humans

The aim of the present study was to determine the sequence of events leading to formation of gallstones among obese patients predisposed to cholesterol gallstones by a very low-calorie diet. Nine obese patients beginning a 520-kcal diet had gallbladder bile collected from the duodenum before beginning the diet and seven times during the first 56 days of the diet. Biliary cholesterol saturation index and levels of arachidonate, prostaglandin E2, and glycoprotein increased significantly; nucleation time decreased; and total lipid concentration did not change. Decreases in nucleation time preceded the appearance of cholesterol crystals. Significant (P less than 0.05) increases in prostaglandin E2 level were preceded by significant increases in arachidonate level and followed by significant increases in glycoprotein level. These observations support the hypotheses that in obese patients predisposed to gallstones by very low-calorie diets (a) decreases in nucleation time are necessary before cholesterol crystals form in the gallbladder; (b) biliary arachidonate, through its conversion to prostaglandins, promotes biliary synthesis and secretion of glycoprotein; (c) biliary glycoprotein promotes nucleation; and (d) increases in the concentration of gallbladder bile are not necessary for cholesterol nucleation to occur in vivo.

Risk factors for gallstone formation during rapid loss of weight

Risk factors for the development of gallstones during rapid weight loss were assessed in 457 subjects who entered a weight control program (520 kcal/day). Absence of gallstones in these subjects was documented by ultrasonography prior to entry into the study. Ultrasonography was performed again at 16 weeks on the subjects who remained in the study (N = 248). The incidence of gallstones by 16 weeks of rapid weight loss was 10.9% (27/248). Most factors associated with gallstones in the general population, eg, older age, female gender, parity, positive family history, etc, were not associated with gallstones in this population. The risk factors for developing gallstones included increased initial body mass index [weight (kg)/height (m)2], amount of body mass index loss, and serum triglyceride levels. The positive predictive value of these risk factors was 75%, but the sensitivity was only 12%. These observations indicate that risk factors for the development of gallstones during rapid weight loss are probably different from those in the general population. The factors identified by this study are useful in predicting patients at high risk for gallstones. However, since only a minority of gallstones that form can be predicted, further study is needed to identify additional factors that will improve our ability to predict gallstone formation.

Ulcer recurrence following duodenal ulcer healing with omeprazole, ranitidine, or placebo: a double-blind, multicenter, 6-month study. The Omeprazole Duodenal Ulcer Study Group

The present study determined whether the rate of relapse of duodenal ulcer was reduced after ulcer healing with omeprazole compared with ranitidine or placebo. It was made up of a double-blind, randomized, controlled multiple-center trial set within the United States. Patients were candidates if their duodenal or pyloric channel ulcer successfully healed in one of two large multicenter U.S. trials; one compared omeprazole, 20 mg once daily, before breakfast with ranitidine, 150 mg twice daily, and the other compared the same dose of omeprazole with placebo. Two hundred forty (73.8%) of the 325 patients with complete ulcer healing within 4 weeks of starting therapy who were eligible to enter the follow-up study were enrolled. There was no intervention. Endoscopic assessment of ulcer status was performed at 2, 4, and 6 months and whenever patients had symptoms thought to represent return of an ulcer. The lifetable relapse rates for duodenal ulcer according to initial ulcer therapy with omeprazole, ranitidine, or placebo were 76.7% [95% confidence interval (CI), 64%-89.3%], 59.8% (95% CI, 47.8-71.7%), and 50.4% (95% CI, 15.7%-85.2%), respectively. These rates were not statistically significantly different. Seventeen percent of recurrent ulcers occurred at a site different from that of the original ulcer. It is concluded that despite the more rapid rate of duodenal ulcer healing with omeprazole therapy, the rate of ulcer relapse appears similar and independent of whether ulcer healing was accelerated with omeprazole or ranitidine.

Roles of deoxycholate and arachidonate in pathogenesis of cholesterol gallstones in obese patients during rapid loss of weight

Our aim was to examine the relationship between biliary deoxycholate and arachidonate in obese patients and the relationship of deoxycholate and arachidonate to the stimulation of biliary mucous glycoprotein among obese patients predisposed to cholesterol gallstones. Thirty-four obese patients predisposed to cholesterol gallstones by a weight-reducing diet (520 kcal/day) received placebo, ursodiol (1200 mg/day), or aspirin (1300 mg/day). Duodenal bile was collected prior to beginning the diet and at four weeks. There was no correlation between deoxycholate and arachidonate among the 34 patients before beginning the diet. With placebo, deoxycholate decreased while arachidonate and glycoprotein increased. With ursodiol, deoxycholate decreased while arachidonate decreased and glycoprotein did not change. With aspirin, there was no change in deoxycholate but a decrease in arachidonate and no change in glycoprotein. Our data do not support a role for biliary deoxycholate in the regulation of biliary arachidonate. Our data do support a role for arachidonate, but not deoxycholate, in the regulation of biliary glycoprotein during the formation of cholesterol gallstones.

Factors affecting the measurement of cholesterol nucleation in human gallbladder and duodenal bile

The study of cholesterol gallstone disease would be facilitated if the nucleation time of cholesterol crystals could be measured in duodenal bile and was correlated with nucleation occurring in vivo. Therefore, our aims were to determine (a) if nucleation time could be measured in duodenal bile, (b) the effect of bacteria, phospholipase, protease, and dilution on the measurement of nucleation time, and (c) the ability of nucleation time of duodenal bile to reflect changes occurring in vivo that promote the formation of gallstones and, therefore, the potential usefulness of nucleation time in predicting and studying the formation of gallstones. Gallbladder bile was obtained from 27 patients undergoing elective cholecystectomy and 19 patients undergoing diagnostic duodenal biliary drainage. Among the 14 bile samples collected by drainage that nucleated within 21 days, mean nucleation time was 6.3 +/- 2.8 days. The addition of inhibitors of phospholipase or protease prolonged nucleation time slightly. Bacteria were cultured from one bile sample at the time of collection and five samples at the time of nucleation. The addition of antibiotics had no effect on nucleation time. Dilution of bile collected at cholecystectomy to the concentration of duodenal bile prolonged nucleation time. In 4 of 5 obese patients receiving a very low calorie diet and predisposed to gallstones, the nucleation time in duodenal bile shortened, and the shortest nucleation times were associated with the formation of cholesterol crystals in vivo. Thus, measurement of nucleation time in duodenal bile may be useful in predicting and studying the formation of cholesterol gallstones.

Gallstones: an update

Gallstones are a major health problem in the United States. More than 20 million Americans have gallstones, and a million new cases are discovered each year. A resurgence of interest in this field has been stimulated by advances in understanding the pathogenesis of cholesterol gallstones and in nonsurgical treatments. The purpose of this symposium is to update these advances.

Effects of ursodeoxycholic acid and aspirin on the formation of lithogenic bile and gallstones during loss of weight

We attempted to determine whether the administration of aspirin or ursodeoxycholic acid during loss of weight could prevent the development of lithogenic changes in bile and the formation of gallstones. Sixty-eight obese subjects without gallstones who were entered in a program (520 kcal per day) to lose weight were randomly assigned to receive ursodeoxycholic acid (1200 mg per day), aspirin (1300 mg per day), or placebo in double-blind fashion for up to 16 weeks. At entry, at four weeks of treatment, and at three weeks after the completion of treatment, the subjects underwent ultrasonography to detect gallstones and duodenal drainage of bile to detect cholesterol crystals and to determine the bile saturation index and glycoprotein concentration. No gallstones or cholesterol crystals formed in the patients treated with ursodeoxycholic acid. Among the patients given placebo, gallstones formed in five (P less than 0.05 vs. ursodeoxycholic acid) and cholesterol crystals in six (P less than 0.001 vs. ursodeoxycholic acid); among those given aspirin, gallstones formed in two and cholesterol crystals in one (no significant difference from ursodeoxycholic acid treatment). By the fourth week, the bile saturation index increased in the placebo group (from 1.07 +/- 0.26 to 1.29 +/- 0.27; P less than 0.001), decreased in the ursodeoxycholic acid group (from 1.11 +/- 0.34 to 0.91 +/- 0.24; P less than 0.001), and did not change significantly in the aspirin group. The concentration of glycoprotein in bile increased in the placebo group (27.9 +/- 14.5 percent; P less than 0.001) but did not change significantly in the groups treated with ursodeoxycholic acid or aspirin. We conclude that ursodeoxycholic acid prevents lithogenic changes in bile and the formation of gallstones in obese subjects during loss of weight.

Failure of episodic high-dose oral verapamil therapy to convert supraventricular tachycardia: a study of plasma verapamil levels and gastric motility

The practicality of administering large oral doses of verapamil tablets to terminate supraventricular tachycardia (SVT) was investigated in 10 patients. A pilot study in four patients showed that unexpectedly low plasma levels (less than 40 ng/ml) were obtained 60 minutes after administering 160 mg or 240 mg of verapamil during SVT. Nuclear studies in the six other patients showed that fractional liquid gastric emptying times (T) were significantly prolonged in SVT compared to sinus rhythm (SR), p less than 0.05 from T 1/3 onward. Further verapamil absorption studies (200 to 360 mg) performed during SVT and SR in five of six patients showed that peak verapamil levels in four patients in SVT were 23% to 71% lower than in sinus rhythm, where they had peaked at greater than 250 ng/ml 60 minutes post verapamil ingestion, and areas under the plasma concentration time curves were 26% to 100% (mean 67%) less in SVT than in SR for all five patients. SVT was terminated by verapamil in one patient after 40 minutes and the rate of SVT was slowed after 90 minutes in two other patients. Thus plasma verapamil levels are considerably reduced during SVT as compared to SR, and changes in gastric emptying are likely a contributing cause. Since SVT was converted to sinus rhythm in only 1 of 10 patients within 1 hour, large oral doses of verapamil tablets appear unsatisfactory for the episodic treatment of SVT.

The effect of diet on bile acid kinetics and biliary lipid secretion in gallstone patients treated with ursodeoxycholic acid

Effects of specific dietary alterations in patients with radiolucent gallstones treated with ursodeoxycholic acid (UDCA, 750 mg at bedtime) were investigated. Patients were allocated randomly to one of four diets: standard (500 mg cholesterol/day), low-cholesterol (250 mg/day), added-bran (30 g/day), or substituted medium-chain triglycerides (MCT) oil (20% of fat). Dietary intake and good compliance were verified by computerized analysis of dietary diaries. Bile-acid kinetics (26 patients) or secretion of biliary lipids (23 other patients) were determined at enrollment and at 6 and 9 mo, respectively, during treatment. Although MCT further decreased the UDCA-induced decrease in the synthesis of chenodeoxycholic acid, it did not lessen desaturation of bile. Otherwise, compared to the standard diet, no experimental diet significantly altered the UDCA-induced increase of the pools of total bile acids and UDCA or the UDCA-induced decrease in synthesis of bile acids and in biliary secretion or saturation of cholesterol. If these dietary manipulations facilitate dissolution of gallstones by UDCA, they do so by other mechanisms.

Effect of dietary cholesterol on biliary lipids in patients with gallstones and normal subjects

The purpose of this study was to determine the effect of dietary cholesterol on biliary lipids in subjects with and without gallstones. Twelve patients with asymptomatic gallstones (six men, six women) were assigned diets containing 500, 750, and 1000 mg cholesterol daily for 3-wk periods in random sequence. Seven healthy women similarly were assigned diets containing 500 and 1000 mg cholesterol daily. With increasing dietary cholesterol in patients with gallstones, biliary saturation indices and molar percents of cholesterol and phospholipids increased significantly while molar percent of biliary bile acids decreased significantly. With increasing dietary cholesterol in healthy women, the biliary saturation index and molar percent of cholesterol increased significantly; the mean saturation index exceeded unity on the diet containing 1000 mg cholesterol daily. In conclusion, augmented dietary cholesterol for brief periods increased biliary cholesterol saturation in subjects with and without gallstones.

Lack of correlation between serum lipoproteins and biliary cholesterol saturation in patients with gallstones

It has been suggested that elevated serum lipoprotein cholesterol levels may be a determinant of biliary cholesterol saturation and cholesterol gallstone disease. The aim of this study was to correlate serum lipoprotein cholesterol and apolipoprotein levels with biliary cholesterol saturation in patients with gallstones who participated in the National Cooperative Gallstone Study. Baseline serum lipoprotein and biliary lipid levels were studied in 181 of these patients before they received treatment for dissolution of their gallstones. Neither low- or high-density lipoprotein cholesterol nor apolipoprotein levels correlated with biliary cholesterol saturation. This study, therefore, does not support the concept that serum lipoproteins are a determinant of biliary cholesterol saturation. It is possible, however, that a significant effect of lipoprotein levels is obscured by the greater effects of more important determinants of biliary cholesterol saturation.

Intermittency of cholesterol crystals in duodenal bile from gallstone patients

The detection of cholesterol crystals in duodenal bile is of clinical value in the diagnosis of cholesterol gallstone disease; however, not all patients with cholesterol gallstones have crystals detected in their duodenal bile, thus limiting the value of examination of duodenal bile. The aims of this study were to (i) determine whether the lack of crystals in some patients with cholesterol gallstones was due to (a) the intermittent presence of crystals, (b) spontaneous crystal dissolution, or (c) changes in dietary cholesterol intake; (ii) determine whether incubation of duodenal bile for 24 h would result in crystal formation. Sixteen patients with radiolucent gallstones each underwent three duodenal biliary drainages. Thirty-one percent of patients had crystals in all three bile specimens, 12% in two specimens, 25% in one specimen, and 32% in no specimen. One of 31 specimens with small numbers of crystals initially had no crystals at 24 h, and five specimens initially devoid of crystals developed crystals by 24 h. Despite a significant increase in biliary cholesterol saturation index with increasing cholesterol intake, the prevalence of crystals in bile did not increase in gallstone patients. No crystals were identified in 18 specimens from normal subjects examined initially or in the 15 specimens that were examined after 24 h. We conclude that the intermittent presence of cholesterol crystals in duodenal bile is probably not due to dissolution of crystals or varying dietary cholesterol intake and that the frequency with which crystals are found increases with incubation. Determination of the diagnostic value of multiple duodenal biliary drainages or incubation of bile in patients with normal oral cholecystograms or gallbladder ultrasonograms, however, will require examinations of large numbers of patients.

Cyclic nucleotides and glycoproteins during formation of cholesterol gallstones in prairie dogs

Male prairie dogs received in standard diets either 0.08% cholesterol (control, n = 30) or 1.2% cholesterol (lithogenic, n = 31). Animals were killed at days 2-4, 7, 10, 21, and 39 to determine the temporal sequence of changes in mucosal cyclic adenosine 3':5'-monophosphate in the gallbladder and of cholesterol saturation, glycoproteins, cholesterol crystals, and gallstones in bile of prairie dogs fed a cholesterol-rich lithogenic diet. Glycoprotein concentration in bile in the lithogenic group was significantly elevated compared to controls on all days of death. Saturation of bile and formation of cholesterol crystals occurred only in the lithogenic group, detected first after 7 days of feeding. Gallstones were found in the lithogenic group only. Elevation of cyclic adenosine 3':5'-monophosphate in the mucosa of gallbladders was found in the lithogenic group only, beginning at day 10. In summary, increased glycoproteins in bile preceded cholesterol saturation and crystallization which, in turn, preceded increased mucosal cyclic adenosine 3':5'-monophosphate.

Low-dose chenodiol to prevent gallstone recurrence after dissolution therapy

Chenodiol is a safe and effective agent for the medical dissolution of gallstones in selected patients; however, after dissolution and cessation of treatment, gallstones recur. This study was done to determine the recurrence rate after successful medical treatment and cessation of chenodiol therapy; compare the efficacy and safety of low-dose chenodiol, as compared to placebo, for prophylaxis against recurrence; and identify factors predictive of recurrence. In a randomized, double-blind fashion, 53 patients with gallstone dissolution received either chenodiol, 375 mg/d, or placebo, for at least 2 years. Standardized oral cholecystograms were done at 6 months, 1 year, and then yearly thereafter. Routine laboratory testing was done every 6 months. The cumulative rate of recurrence (life-table) was 27% in patients followed for up to 3.5 years. Chenodiol, 375 mg/d, was ineffective in preventing the recurrence of gallstones. No demographic, clinical, roentgenographic, or biochemical characteristics were predictive of recurrence.

Additional chenodiol therapy after partial dissolution of gallstones with two years of treatment

During the National Cooperative Gallstone Study, therapy with chenodiol, 750 or 375 mg/d, for 2 years resulted in confirmed, complete gallstone dissolution in 14% and 5% of patients, respectively, and partial dissolution (greater than 50%) in 27% and 18%. The present study was done to determine the frequency with which complete dissolution occurs in patients having partial dissolution of gallstones who receive additional therapy. Eighty-six of one hundred thirty-eight eligible patients continued to receive 750 mg/d (61 patients) or 375 mg/d (25 patients) of chenodiol for 1 year. Patients whose oral cholecystogram at the end of the year showed further (greater than 50%) dissolution continued to receive chenodiol, (28 patients at 750 mg/d and 11 patients at 375 mg/d) for a second year (total duration of therapy, 4 years). A final oral cholecystogram was taken at the end of the fourth year. Complete dissolution occurred in 23% and 16% of patients receiving chenodiol, 750 or 375 mg/d, respectively, for an additional 1 or 2 years.

Major issues in the organization and implementation of the National Cooperative Gallstone Study (NCGS)

The National Cooperative Gallstone Study (NCGS) was a cooperative, randomized, controlled trial of a drug, chenodiol, for the medical dissolution of gallstones. The design and procedures of the NCGS were complex, having developed as a result of extensive involvement of many experts in the field of gallstone disease and biliary lipids. During the design and implementation of the protocol, many important issues required consideration and resolution. The aim of this article is to review these issues and the deliberations surrounding their resolution and provide personal conclusions and recommendations that may be helpful to other investigators involved in cooperative, controlled trials.

Rowachol and ursodeoxycholic acid in hamsters with cholesterol gallstones

Rowachol, a mixture of 6 terpenes in olive oil and under investigation for dissolution of gallstones in humans, was compared with UDCA in hamsters with induced cholesterol gallstones. Eighty hamsters were allocated to eight groups of ten animals each. One group received only standard rodent chow. The other seven groups received the lithogenic regime (standard chow containing ethinyl estradiol and increased cholesterol), either alone or with 20 mg/kg/day of UDCA, or 5, 10, or 20 mg/kg/day of mixed terpenes in olive oil or 10 mg ( of terpenes) kg/day of Rowachol or 0.2 cc/day of olive oil. The animals were sacrificed after 12 weeks. Two additional groups of six hamsters each received the lithogenic regime for 12 weeks, and then were switched to the standard diet, alone or with 10 mg/kg/day of Rowachol for eight weeks at the end of which time they were sacrificed. Rowachol decreased HMGCoA reductase activity 18%, but did not dissolve gallstones. Neither the terpenes nor Rowachol altered the biliary cholesterol saturation index, bile acid pool size or the activity of cholesterol 7-alpha hydroxylase or prevented formation of gallstones. UDCA unsaturated bile, increased the total bile acid pool size 38%, depressed the activity of HMGCoA reductase 29%, and prevented formation of gallstones.

Enrichment of bile with tauroursodeoxycholic acid and biliary cholesterol saturation in hamsters

Three groups of golden Syrian hamsters were fed equimolar amounts of taurine-conjugated ursodeoxycholic acid (TUDCA) or unconjugated ursodeoxycholic acid (UDCA) with or without excess taurine for 2 wk. They also received a lithogenic diet composed of standard rodent chow containing ethynylestradiol and increased cholesterol. Bile was obtained from the gallbladder after ketamine anesthesia and analyzed for biliary lipids. The percentage of biliary UDCA was higher with TUDCA (38.5 +/- 3.7) than with UDCA plus taurine (26.5 +/- 2.0, P less than 0.01). The glycine-to-taurine ratio of biliary UDCA conjugates was lower with TUDCA (0.9 +/- 0.1) than with UDCA plus taurine (2.1 +/- 0.2, P less than 0.01) and was highest with UDCA without taurine (4.1 +/- 0.1, P less than 0.01). Biliary cholesterol (molar percentage) and the cholesterol saturation indices with or without correction for UDCA-rich bile were significantly lower with TUDCA than with unconjugated UDCA with or without added taurine. In conclusion, administration for 2 wk of TUDCA, compared with an equimolar amount of unconjugated UDCA plus taurine, produced in the bile of hamsters a higher percentage of UDCA, a lower glycine-to-taurine ratio of UDCA conjugates, and a lower saturation index before and after adjustment for UDCA-rich bile.

Pretreatment biliary lipid composition in white patients with radiolucent gallstones in the National Cooperative Gallstone Study

Biliary lipid classes (bile acids, phospholipids, cholesterol) as well as individual biliary bile acids were measured in duodenal bile samples obtained before treatment from 284 white men and 264 white women participating in the National Cooperative Gallstone Study. The patients had radiolucent gallstones present in visualizing gallbladders. Calculated biliary cholesterol saturation was significantly higher in women (143 +/- 43, mean +/- SD, vs. 132 +/- 39 for men). Chenodeoxycholic acid was the major biliary bile acid in both sexes (40.0 +/- 9.9 in men; 38.8 +/- 9.3 in women, NS). Cholic acid was the second most common bile acid, constituting 32.9 +/- 8.8 in men and 31.8 +/- 8.9 in women (NS). When other demographic and clinical characteristics, including serum lipids, were related with biliary lipid composition, only percent ideal body weight correlated significantly. The partial correlation coefficient adjusted for percent ideal body weight indicated that the proportion of chenodeoxycholic acid correlated negatively with the mole fraction of cholesterol in bile in men, but not in women. Multiple regression analyses showed that bile saturation could not be predicted reliably from any clinical, chemical, or radiologic measurement in either sex. Published data for biliary lipid composition in individuals with biliary disease showed considerable overlap with the National Cooperative Gallstone Study data reported here, suggesting that cholesterol gallstone disease is not caused solely by increased biliary cholesterol saturation.

Dissolution of cholesterol gallstones by bile acids in hamsters

We previously reported a hamster model for cholesterol gallstone formation and prophylaxis. The aim of this study was to validate a model for dissolution of cholesterol gallstones by testing bile acids used in patients. Sixty hamsters were allocated to six groups of ten; Group I received the standard diet (.8mg cholesterol/gram food) and Groups II-VI received the lithogenic regime (2.4 mg cholesterol/gram food and 15 micrograms ethinyl estradiol) for twelve weeks. During the next eight weeks, Group I remained on the standard diet, Group II on the lithogenic regime, while Group III switched to the standard diet. Groups IV-VI remained on the lithogenic regime, and received 20 mg/kg/d of CDC (Group IV), UDC (Group V) or cholic acid (Group VI). Cholesterol gallstones were found in 90% of hamsters on the lithogenic regime, even after return to the standard diet, in 80% of those receiving cholic acid, and in none receiving the standard diet, CDC or UDC. CDC and UDC but not cholic acid inhibited hepatic HMG-CoA reductase activity (p less than 0.01) and desaturated bile (p less than 0.01). The highest HMG-CoA reductase (p less than 0.02) occurred after return from the lithogenic regime to the standard diet.

CONCLUSIONS

1) A new model for cholesterol gallstone dissolution has been validated; 2) CDC and UDC, in contrast to cholic acid, decreased HMG-CoA reductase, desaturated bile and dissolved gallstones as in patients; and 3) Return from the lithogenic regime to the standard diet did not desaturate bile or dissolve gallstones, but did increase HMG-CoA reductase as found in gallstone patients.

Effect of Zanchol and chenic acid on bile acid pool size and gallstones in hamsters

After receiving a lithogenic regime for 12 weeks (Phase I), 60 hamsters were allocated to groups of 10 animals. During Phase II, except for one group which remained on the lithogenic regime, all groups were switched to a standard diet and chenic acid 20 mg/kg/day or Zanchol 5, 15 or 25 mg/kg/day or no other therapy. Half the animals in each group were sacrificed at 3 weeks and the remainder at 10 weeks. Gallstones were found in all animals except those receiving chenic acid for 10 weeks. At 3 weeks in Phase II, with chenic acid, the bile acid pool size was not significantly decreased and bile remained saturated despite a 38% lower rate of hepatic synthesis of cholesterol (p less than 0.01), but became unsaturated at 10 weeks at which time the bile acid pool size was increased by 37% (p less than 0.01). The highest at which time the bile acid pool size was increased by 37% (p less than 0.01). The highest dose of Zanchol increased the bile acid pool size by 74% (p less than 0.01) while increasing the hepatic synthesis of file acid by 38% (p less than 0.01). None of the doses of Zanchol, however, significantly changed biliary cholesterol saturation. In conclusion, chenic acid decreased the hepatic synthesis of cholesterol prior to increasing the bile acid pool, unsaturating bile and dissolving gallstones. Zanchol did not affect the biliary cholesterol saturation of dissolve gallstones despite an increase in the synthesis and pool size of the bile acids.

Sulfation of lithocholate as a possible modifier of chenodeoxycholic acid-induced elevations of serum transaminase in patients with gallstones

Chenodeoxycholic acid (CDC), through its metabolite, lithocholic acid (LC), is hepatotoxic in certain species. The cause of elevations of serum transaminase in 25% of humans ingesting CDC, however, is unknown, but also may be due to LC. Because efficient hepatic sulfation of LC may protect against hepatic injury, the aim of this study was to determine if sulfation of LC might modify CDC-induced elevations of transaminase. Pretreatment sulfation fraction (SF) was estimated in 63 randomly selected patients with gallstones in a double-blind randomized trial of CDC, 750 mg/d, 375 mg/d, or placebo; in 27 of these, SF was repeated at 1 or 2 yr. In four other patients, the SF was measured at 2 yr only. Serum glutamic oxaloacetic transaminase and serum glutamic pyruvic transaminase were determined monthly for 3 mo and then every 3 or 4 mo; an elevation of transaminase was defined as > 150% of the normal upper limit in asymptomatic patients. 10 muCi of (3)H-glyco-LC (sp act 84 mCi/mol) was ingested 10-12 h before fasting duodenal biliary drainage. Bile acids in bile were separated by thin-layer chromatography. The SF was estimated as a percentage of total radioactivity (scintillation counting) in sulfated glyco-LC. The standard deviation for replicate SF determinations (n = 311) was 2.1% The pretreatment SF (mean 60.7+/-1.7 SEM) correlated inversely with age (r = 0.336, P < 0.005) and directly with the obesity index (r = 0.495, P > 0.001), but was independent of sex. The SF, remeasured at 1 or 2 yr, did not change significantly with time or CDC. Among CDC-treated patients, elevations of transaminase occurred in 75% of patients with a SF < 45% vs. 11% with a SF > 45% (P < 0.001). In conclusion, a SF < 45% occurred in patients with gallstones who had a high probability of developing elevated serum transaminase when treated with CDC. Thus, sulfation of lithocholate may modify CDC-induced elevations of serum transaminase.

Treatment of choledocholithiasis with oral chenodeoxycholic acid

The aim of this study was to conduct a controlled trial of oral chenodeoxycholic acid in the management of radiolucent choledocholithiasis. Thirteen patients were randomized in double-blind fashion to receive either 750 mg/day of chenodeoxycholic acid (CDCA) or a placebo. After 4 months, those who had the placebo were administered CDCA; those who had received CDCA and showed a 25% or more decrease in the size of stones (evaluated blindly) received CDCA for an additional 4 months. Five of the 13 patients did not complete the study; four (one initially placebo and three CDCA) because acute biliary symptoms mandated operative intervention and one (initially placebo, then CDCA) because of asymptomatic elevations of the serum transaminase levels. Patients who were withdrawn from the study had significantly larger stones (P less than 0.02) (mean largest diameter, 11.4 mm +/- 1.6 SEM) than those who completed the study (6.5 +/- 0.5). Of the eight patients who completed the study, two of the three who received CDCA initially for 6 to 8 months experienced complete disappearance of stones; all five patients who took the placebo failed to show dissolution, and one of these subsequently had dissolution of stones after 8 months of CDCA. Biliary lipid analyses during treatment showed bile unsaturated with respect to cholesterol in the three patients whose stones dissolved with CDCA therapy. In conclusion, a patient with partial dissolution of stones and unsaturated bile after 4 months of CDCA probably will have complete dissolution of stones after 6 to 8 months of CDCA.

Reflux gastritis syndrome: mechanism of symptoms

Despite numerous observations indicating the deleterious effect of refluxed intestinal contents upon the stomach, the mechanism of injury and symptoms in the reflux gastritis syndrome is unclear. Much speculation has centered around the role of bile acids in the production of symptoms and histologic damage. Accordingly, the aims of our study were (a) to determine whether administration of autologous intestinal contents into the stomach can produce the symptoms of the reflux gastritis syndrome, (b) to measure and conpare the concentrations of bile acids in upper intestinal contents of postsurgical patients with and without the syndrome, and (c) to determine whether artificial bile acid solutions can reproduce the symptoms reported by the patients. Eleven patients with reflux gastritis syndrome and 10 asymptomatic postgastric surgery patients were evaluated. Autologous intestinal contents obtained after cholecystokinin injection and normal saline were infused in a random, double-blind fashion into the stomach of the patients. Determinations for total and individual bile acids, as well as the bile acid conjugated/unconjugated and glycine/taurine ratios were made on aliquots of upper intestinal contents of symptomatic and asymptomatic patients. Finally, saline and two artificial bile acid solutions with bile acid compositions similar to those of upper intestinal contents from symptomatic and asymptomatic patients were infused in random, double-blind fashion into the stomach of 8 patients from each group. Positive symptom responses to autologous intestinal contents were found in 10 of 11 symptomatic patients and only 2 of 10 asymptomatic patients (P < 0.01), both of whom showed positive responses to both autologous intestinal contents and saline. No symptomatic patients had a positive response to saline. Symptomatic patients had bile acid concentrations significantly greater (P < 0.001) than asymptomatic patients. A positive response to artificial bile acid solution infusion was found in only 1 symptomatic patient. It is concluded that (a) symptoms of the reflux gastritis syndrome are reproduced by gastric infusion of upper intestinal contents and (b) bile acids alone are not responsible for the production of symptoms.

Biliary lipid synthesis and secretion in gallstone patients before and during treatment with chenodeoxycholic acid

The interrelationships between biliary lipid secretion and the hepatic activities of the rate-limiting enzymes for bile acid and cholesterol synthesis have not been investigated in patients with gallstones before and during desaturation therapy. Liver biopsies for enzyme assays and biliary lipid secretion measurements were performed in 12 patients with gallstones before chenodeoxycholic acid therapy and in nine of these patients at 9 months of therapy. Six nongallstone control patients underwent only the lipid secretion measurements. In the patients with gallstones before treatment, all of whom had saturated bile, increased cholesterol secretion correlated directly with increased HMGCoAR activity, whereas bile acid and phospholipid secretion rates were significantly lower than in controls. During desaturation in response to chenodeoxycholic acid, biliary cholesterol and phospholipid secretion rates decreased significantly, and bile acid secretion was unchanged. Concomitantly, both HMGCoAR and cholesterol 7alpha-hydroxylase activities decreased significantly, but the correlation between HMGCoAR and cholesterol secretion was lost. Furthermore, no correlation was found between cholesterol 7alpha-hydroxylase activity and bile acid secretion during therapy. Enzyme assays were performed on single liver samples obtained at the same time of day but 48 hr before the lipid secretion measurements. That correlations between data obtained under these conditions are valid remains to be proved. In conclusion, the mechanism of biliary cholesterol saturation in patients with gallstones probably is related primarily to increased hepatic cholesterol synthesis, whereas desaturation during chenodeoxycholic acid therapy involves altered relationships among hepatic enzyme activities and biliary lipid secretions.

The effect of dihydroxy bile acids on intestinal secretion, cyclic nucleotides, and Na+-K+-ATPase

The effects of dihydroxy bile acids on intestinal cyclic nucleotides, Na+-K+-ATPase, and net secretion, and of propranolol pretreatment on these actions were determined. Ileal and colonic loops were constructed in each of 12 rabbits, six of which were treated with propranolol preoperatively. In random order, normal saline, 6mM deoxycholic, chenodeoxycholic, or ursodeoxycholic acids were injected into the intestinal loops. Five hours after, net luminal secretion and mucosal adenylate cyclase, phosphodiesterase, cGMP, and Na+-K+-ATPase were determined. Deoxycholic and chenodeoxycholic acids each increased adenylate cyclase activity (< 0.01) and net secretion (p < 0.01), and decreased cGMP (p < 0.05). Ursodeoxycholic acid did not alter adenylate cyclase activity or secretion but increased cGMP (p < 0.05). Phosphodiesterase and Na+-K+-ATPase were unchanged. Propranolol reversed all of the bile acid effects. In conclusion, chenodeoxycholic and deoxycholic acid induce net intestinal secretion, probably via cAMP. Ursodeoxycholic acid does not affect cAMP but increases cGMP and does not promote net secretion.

Cholesterol gallstone formation and prevention by chenodeoxycholic and ursodeoxycholic acids. A new hamster model

Prior animal models of cholesterol gallstone formation have been criticized for their dissimilarity to the conditions of humans with gallstones. We present a new hamster model of cholesterol cholelithiasis that more closely approximates the human situation. Sixty female Golden Syrian hamsters (average weight 83.2 +/- 3.4 g) were allocated to six groups of 10 animals each. Groups were fed standard diet (containing 0.8 gm cholesterol/g of food) or increased cholesterol diet (containing 2.4 mg cholesterol/g of food), with or without ethinyl estradiol, 15 micrograms/kg/d. Two groups receiving both increased cholesterol and ethinyl estradiol also received either chenodeoxycholic acid or ursodeoxycholic acid, 20 mg/kg/d. The animsl were sacrificed at 12 wk. Cholesterol gallstones (78.3 +/- 5.0% cholesterol by weight) formed in 30% of the animals fed ethinyl estradiol, 50% of those fed increased cholesterol, and 90% of those fed the combination of both. Bile was saturated in all three groups, with the saturation index of the combination group (2.08 +/- 0.17) being the highest. In both groups receiving bile acid therapy, no gallstones were found, and the bile remained unsaturated. For the bile acid-fed groups, both hepatic HMG-CoAR and hepatic cholesterol 7 alpha-hydroxylase activities were reduced (P less than 0.01) when compared to the group fed standard diet and to the grou fed the combination. Thus, a new animal model of cholesterol gallstone formation has been developed in which chenodeoxycholic acid and ursodeoxycholic acid therapy prevented gallstone formation through mechanisms similar to those reported in cholesterol gallstone patients.

BCG treatment of Crohn's disease

Among 53 patients with documented Crohn's disease, 30% manifested a defect in delayed hypersensitivity demonstrated by negative DNCB skin tests and significant (p less than 0.01) T-lymphocyte hyporeactivity. A double-blind controlled trial was conducted to evaluate oral Bacillus Calmette-Guerin (BCG) therapy in nine of these patients with Crohn's disease and deficient cellular immunity. All patients had a Crohn's Disease Activity Index (CDAI) greater than 150 (at least moderate activity) upon randomization to BCG (five patients) or placebo (four patients) treatment for six to 12 months. No significicant differences between BCG and placebo treatment were found in the CDAI, laboratory tests and gastrointestinal roentgenograms. We conclude that the disturbance in cell-mediated immunity in patients with Crohn's disease probably is a manifestation of the disease rather than an etiological factor and that immunostimulation with oral BCG is not effective therapy.

Gallstone dissolution--a progress report

Cholesterol gallstone formation occurs in three stages. First, the bile must be saturated with cholesterol, thereby allowing cholesterol crystals to form. Then, nucleation and growth of the gallstone can occur, although little is known about these latter two stages. Therapy for dissolution of gallstones is directed at desaturating the bile. Chenodeoxycholic acid (CDCA), the most extensively tested agent, is successful in dissolving 60 per cent of radiolucent gallstones; however, long-term safety remains to be demonstrated. Ursodeoxycholic acid (UDCA), the 7 beta epimer of CDCA, is a promising agent for cholesterol gallstone dissolution, but it, other potential agents, and dietary manipulations require more extensive study. An important problem, the prevention of recurrence of gallstones after dissolution, also needs resolution. Medical dissolution probably will be applicable as an alternative to cholecystectomy for most patients with radiolucent gallstones, but the specific relative indications remain to be determined. A variety of modalities, both medical and surgical, are being used for the treatment of retained or reformed bile duct stones. These include T-tube infusions, oral CDCA, and extraction either through the T-tube tract or after endoscopic papillotomy. Further studies, including controlled trials, are necessary to determine the relative indications for these methods.

Gallstone dissolution by chenodeoxycholic acid and phenobarbital

Gallstone dissolution and biliary lipids were determined and compared in patients receiving either chenodeoxycholic acid (CDC), or CDC and phenobarbital (PB) for 11/2 to 2 years. Among patients with radiolucent gallstones, dissolution occurred in 53% of those receiving CDC alone and in only 25% of those receiving both CDC and PB. No dissolution occurred in 13 other patients with calcified gallstones. Patients with dissolution had a significantly greater molar percentage of CDC and a significantly lower saturation index in bile than those without dissolution. Diarrhea and transiently abnormal liver function tests were the most frequently observed side-effects but only diarrhea necessitated a reduction of the CDC dose. Gallstones recurred following dissolution in one of six patients followed for six months after discontinuation of CDC. In conclusion, PB did not enhance CDC-induced desaturation of bile or gallstone dissolution.

Gallstone prevalence and biliary lipid composition in inflammatory bowel disease

Biliary cholesterol saturation has been correlated with disease variables that might effect bile acid loss in ileitis patients with (N = 9) or without (N = 8) intestinal resection having a defined prevalence of gallstones. In addition, cholesterol saturation was determined in ulcerative colitis patients (N = 7) and gallstone patients (N = 18) as well as in 5 normal controls. Biliary cholesterol saturation in ileitis patients both with and without resection was similar to that in gallstone patients yet the prevalence of gallstones was only 12%. Cholesterol saturation did not correlate with ileal resection nor the extent, duration, or activity of ileitis. Biliary cholesterol saturation was not different in ulcerative colitis patients from that in normal subjects. It is concluded that cholesterol saturation of bile alone does not account for the high prevalence of cholesterol gallstones that has been reported in ileitis patients.

Feasibility of low-dose and intermittent chenodeoxycholic acid therapy of gallstones

Chenodeoxycholic acid, by reducing the concentration of biliary cholesterol relative to that of bile acid and phospholipid, dissolves cholesterol gallstones. This bile acid, however, has potential dose-related hepatotoxicity and causes dose-related diarrhea. Therefore, the feasibility of low-dose and intermittent therapy was assessed by studying the induction and persistence of chenodeoxycholic acid-induced biliary lipid changes. Biliary lipid composition with each of 3 doses of chenodeoxycholic acid was determined in bile samples obtained by cholecystokinin-stimulated duodenal drainage before, after one week and one month of treatment, and up to 9 weeks after discontinuation of treatment. The lowest dose that significantly reduced the relative concentration of biliary cholesterol was 250 mg/day. A significant reduction occurred one week after initiation of treatment and was maintained for 9 weeks following discontinuation of treatment. Thus, clinical trials on low-dose and intermittent chenodeoxycholic acid therapy for gallstone prophylaxis or dissolution are warranted.