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1.
Aliment Pharmacol Ther ; 20(5): 567-75, 2004 Sep 01.
Article in English | MEDLINE | ID: mdl-15339328

ABSTRACT

AIM: To compare the safety and efficacy of pantoprazole and ranitidine in maintaining erosive oesophagitis healing. METHODS: Gastro-oesophageal reflux disease patients (349) with endoscopically documented healed erosive oesophagitis (grade 0 or 1) were randomly assigned to receive pantoprazole (10, 20 or 40 mg/q.d.s.) or ranitidine (150 mg/b.d.). Erosive oesophagitis status was assessed endoscopically at months 1, 3, 6 and 12 or when relapse symptoms appeared (relapse = reappearance of erosive oesophagitis grade 2 within 12 months). Symptom-free days were also assessed. RESULTS: Pantoprazole 20- and 40-mg were significantly more effective than ranitidine in maintaining healing regardless of initial erosive oesophagitis grade. Response was dose-related. After 12 months 78, 55, 46 and 21% of patients remained healed (40-, 20-, 10-mg pantoprazole and ranitidine). Pantoprazole 40-mg produced significantly more symptom-free days (83%) than ranitidine (58%). Heartburn-free days/nights were significantly higher with pantoprazole 40-mg (92 and 93%) than ranitidine (73 and 77%). The most frequent reason for discontinuation, unsatisfactory efficacy, occurred most often with ranitidine (P < 0.001). CONCLUSION: Once-daily pantoprazole therapy prevented relapse of healed erosive oesophagitis more effectively than ranitidine and with fewer heartburn days. Response to pantoprazole was dose-related. Pantoprazole 40-mg was the most effective regimen and consistent in maintaining erosive oesophagitis healing with a good safety and tolerability profile.


Subject(s)
Anti-Ulcer Agents/therapeutic use , Benzimidazoles/therapeutic use , Esophagitis/prevention & control , Gastroesophageal Reflux/drug therapy , Omeprazole/analogs & derivatives , Omeprazole/therapeutic use , Sulfoxides/therapeutic use , 2-Pyridinylmethylsulfinylbenzimidazoles , Double-Blind Method , Female , Humans , Male , Middle Aged , Pantoprazole , Secondary Prevention , Survival Analysis
2.
Aliment Pharmacol Ther ; 11(2): 373-80, 1997 Apr.
Article in English | MEDLINE | ID: mdl-9146778

ABSTRACT

INTRODUCTION: Relapse of erosive oesophagitis occurs in almost all patients if treatment is stopped after initial healing. AIM: To assess the potential of different therapeutic regimens of omeprazole to prevent relapse of erosive reflux oesophagitis after initial healing with omeprazole. PATIENTS AND METHODS: Patients whose active erosive reflux oesophagitis (grade > or = 2) had healed (grade 0 or 1) after 4-8 weeks of open-label omeprazole 40 mg daily (phase I) were eligible to join a multi-centre, 6-month double-blind, placebo-controlled maintenance study (phase II), which included endoscopy, symptom assessments, serum gastrin measurements, and gastric fundic biopsies. During phase I, endoscopy was performed at weeks 0, 4, and 8. At the end of phase I, 429 of 472 patients (91%) were healed, and there were significant reductions in heartburn, dysphagia and acid regurgitation. Of the 429 patients who healed, 406 joined phase II and were randomized to one of three groups: 20 mg omeprazole daily (n = 138), 20 mg omeprazole for 3 consecutive days each week (n = 137), or placebo (n = 131). During phase II, endoscopy was performed at months 1, 3, and 6 or at symptomatic relapse. RESULTS: The percentages of patients still in endoscopic remission at 6 months were 11% for placebo, 34% for omeprazole 3-days-a-week, and 70% for omeprazole daily. Both omeprazole regimens were superior to placebo in preventing recurrence of symptoms (P < 0.001); however, omeprazole 20 mg daily was superior to omeprazole 20 mg 3-days-a-week (P < 0.001). Compared to baseline, omeprazole therapy resulted in no significant differences among treatment groups in the distribution of gastric endocrine cells. CONCLUSIONS: These results show that after healing of erosive oesophagitis with 4-8 weeks of omeprazole, relapse of oesophagitis and recurrence of reflux symptoms can be prevented in 70% of patients with a maintenance regimen of 20 mg daily, but that intermittent dosing comprising 3 consecutive days each week significantly compromises efficacy.


Subject(s)
Anti-Ulcer Agents/therapeutic use , Esophagitis, Peptic/prevention & control , Omeprazole/therapeutic use , Anti-Ulcer Agents/administration & dosage , Anti-Ulcer Agents/adverse effects , Double-Blind Method , Esophagitis, Peptic/pathology , Female , Humans , Male , Middle Aged , Omeprazole/administration & dosage , Omeprazole/adverse effects , Recurrence
3.
Am J Gastroenterol ; 91(9): 1766-72, 1996 Sep.
Article in English | MEDLINE | ID: mdl-8792695

ABSTRACT

OBJECTIVES: To evaluate complete symptom resolution, mucosal healing, and tolerability of omeprazole, ranitidine, or ranitidine/metoclopramide in patients with poorly responsive, symptomatic gastroesophageal reflux disease (GERD). METHODS: Adults with persistent symptomatic GERD after ranitidine treatment were stratified by esophagitis grade and randomized to omeprazole 20 mg once daily, ranitidine HCI 150 mg twice daily, or ranitidine HCI 150 mg twice daily plus metoclopramide HCI 10 mg four times daily. Endoscopies were conducted at baseline and at wk 4 and 8. Patients assessed overall symptom improvement at wk 4 and 8 and evaluated daytime and nighttime heartburn, dysphagia, and acid regurgitation daily. RESULTS: After 1 wk, 13% of patients receiving omeprazole (N = 100) had complete resolution of all GERD symptoms versus 1% and 3% of patients receiving ranitidine (N = 97) or ranitidine/metoclopramide (N = 93), respectively (p < 0.001). More patients receiving omeprazole had complete symptom resolution at wk 4 (33%) and at the end of the study (64%; both p < 0.001) than patients receiving ranitidine (8% and 28%, respectively) or ranitidine/metoclopramide (7% and 29%, respectively). Regardless of baseline esophagitis grade, more patients receiving omeprazole had complete symptom resolution. At wk 8, more than 91% of patients with grade 0 or 1 esophagitis at baseline were still healed irrespective of treatment. At wk 8, 80% of patients with esophagitis grade 2 or higher at entry were healed with omeprazole (p < 0.001 vs ranitidine [40%] and ranitidine/metoclopramide [46%]). Thirty-four percent of patients reported an adverse event. Significantly more patients receiving combination treatment reported an adverse event than patients treated with single agents. CONCLUSIONS: In patients with persistent GERD symptoms after ranitidine, omeprazole (20 mg daily for up to 8 wk) provides faster and more complete resolution of common GERD symptoms than continued ranitidine (300 mg daily) alone or in combination with metoclopramide (40 mg daily). Omeprazole provides significantly higher rates of endoscopic healing than ranitidine alone or with metoclopramide. Omeprazole and ranitidine are generally well tolerated. The addition of metoclopramide to ranitidine significantly increases adverse events.


Subject(s)
Dopamine Antagonists/therapeutic use , Enzyme Inhibitors/therapeutic use , Esophagitis, Peptic/drug therapy , Histamine H2 Antagonists/therapeutic use , Metoclopramide/therapeutic use , Omeprazole/therapeutic use , Ranitidine/therapeutic use , Dopamine Antagonists/administration & dosage , Dopamine Antagonists/adverse effects , Drug Administration Schedule , Drug Therapy, Combination , Enzyme Inhibitors/administration & dosage , Female , Histamine H2 Antagonists/administration & dosage , Humans , Male , Metoclopramide/administration & dosage , Metoclopramide/adverse effects , Middle Aged , Omeprazole/administration & dosage , Time Factors
4.
J Fam Pract ; 41(2): 126-36, 1995 Aug.
Article in English | MEDLINE | ID: mdl-7636452

ABSTRACT

BACKGROUND: Gastroesophageal reflux disease (GERD), often characterized as heartburn, is a highly common presenting complaint to family physicians. This study is the first large, prospective, nationwide family practice outpatient evaluation of the effectiveness of the histamine (H2)-receptor antagonist ranitidine as medical therapy for this disorder. METHODS: This randomized, double-blind, placebo-controlled, parallel group, 6-week study was designed to evaluate the effect of ranitidine on clinical outcomes and quality of life in patients with GERD. Eligible patients included those who were at least 18 years old and had at least a 3-month history of heartburn or heartburn therapy and a minimum of 4 days with at least one heart-burn episode in the week preceding the baseline visit. Quality-of-life effects were measured using a general health status instrument and a previously validated heartburn-specific questionnaire. RESULTS: Ranitidine treatment conferred clinically and statistically significant reductions in mean heartburn pain scores within the first 24 hours (P < or = .001) and mean number of heartburn episodes within the first 48 hours (P < or = .001). These reductions were maintained throughout the 6-week trial, during both daytime and nighttime. Compared with patients receiving placebo, patients treated with ranitidine also used significantly fewer doses of antacids (P < or = .003). Further, both ranitidine-treated patients' and their physicians' global assessments of decreases in heartburn severity, as well as clinical improvement on ranitidine, proved superior to those of controls (P < or = .001). The rate of adverse events associated with ranitidine and placebo was low and similar. Ranitidine-treated patients had more favorable scores on the general health status dimensions of physical functioning, bodily pain, and vitality (P < .05), and more favorable scores on all dimensions of the heartburn-specific questionnaire (P < .05). CONCLUSIONS: Twice-daily treatment with ranitidine 150 mg is a valuable therapy for GERD in a typical family practice setting. It reduces the frequency and severity of symptoms within the first 24 to 48 hours of treatment and diminishes the use of nonprescription antacids while improving the quality of life as measured by both a general health status instrument and a disease-specific instrument.


Subject(s)
Gastroesophageal Reflux/drug therapy , Heartburn/drug therapy , Quality of Life , Ranitidine/therapeutic use , Adult , Aged , Ambulatory Care , Antacids/therapeutic use , Double-Blind Method , Drug Therapy, Combination , Family Practice , Female , Gastroesophageal Reflux/complications , Heartburn/classification , Heartburn/etiology , Humans , Male , Middle Aged , Prospective Studies , Treatment Outcome , United States
5.
Dig Dis Sci ; 40(3): 590-7, 1995 Mar.
Article in English | MEDLINE | ID: mdl-7895551

ABSTRACT

Fifty-four patients with endoscopically documented therapy-resistant erosive reflux esophagitis were treated with lansoprazole, a new proton pump inhibitor, for up to 12 weeks. Prior to entry, all had remained unhealed after treatment with at least two histamine2-receptor antagonists, at therapeutic doses or higher, for at least 12 weeks. Patients were randomized to receive either 30 or 60 mg lansoprazole once daily. Endoscopy was performed and symptoms assessed at weeks 2,4,6,8 and 12. Fifty-nine percent of the 50 evaluable patients were healed (ie, no evidence of erosions) after only two weeks of lansoprazole. Cumulative endoscopic healing rates were 82% and 92% by week 4 and week 8, respectively, and the two doses were equally effective in healing. The 30- and 60-mg doses effected a decrease in the overall symptom score from 5.30 and 4.85 to 2.35 and 1.67, respectively, by the final treatment visit (P = 0.001). No clinically significant adverse events or changes in laboratory parameters were observed, and no patients withdrew prematurely from the study. This study demonstrates that lansoprazole therapy is highly effective in healing erosive reflux esophagitis resistant to therapy with histamine H2-receptor antagonists.


Subject(s)
Esophagitis, Peptic/drug therapy , Omeprazole/analogs & derivatives , Proton Pump Inhibitors , 2-Pyridinylmethylsulfinylbenzimidazoles , Dose-Response Relationship, Drug , Drug Administration Schedule , Esophagoscopy , Female , Histamine H2 Antagonists/therapeutic use , Humans , Lansoprazole , Male , Middle Aged , Omeprazole/administration & dosage , Omeprazole/therapeutic use , Pilot Projects , Time Factors , Wound Healing
6.
Aliment Pharmacol Ther ; 7 Suppl 2: 35-40, 1993.
Article in English | MEDLINE | ID: mdl-8103374

ABSTRACT

H2-receptor antagonist therapy is associated with a low incidence of adverse reactions. Adverse events reported in clinical trials of ranitidine in daily doses of up to 1200 mg include headache, tiredness and mild gastrointestinal disturbances, but the incidence is similar to or less than that for placebo. High doses of cimetidine (> 5 g/day) can cause reversible impotence or gynaecomastia. While ranitidine exhibits no clinically significant drug-drug interactions, cimetidine interacts with many drugs metabolized by cytochrome P450. In contrast to ranitidine and cimetidine, where safety data are available for up to 10 years of continuous therapy, experience with famotidine and nizatidine is limited. The safety of long-term H2-receptor antagonist therapy needs to be considered in relation to the potential consequences of prolonged acid suppression, including the risk of proliferation of gastric flora and the risk of developing enterochromaffin-like cell hyperplasia, which could in turn, theoretically, lead to gastric malignancy. Such problems have not been observed in patients during long-term therapy at low or full doses of H2-receptor antagonists. Standard doses of currently available H2-receptor antagonists permit acid secretion in response to food and other stimuli, and this daily acid tide prevents persistent bacterial colonization.


Subject(s)
Histamine H2 Antagonists/adverse effects , Peptic Ulcer/drug therapy , Drug Interactions , Histamine H2 Antagonists/therapeutic use , Humans , Peptic Ulcer/complications
7.
Am Surg ; 58(4): 243-8; discussion 248-9, 1992 Apr.
Article in English | MEDLINE | ID: mdl-1586083

ABSTRACT

The safety and efficacy of piezoelectric extracorporeal shockwave lithotripsy in the treatment of symptomatic gallbladder stones were evaluated in 53 consecutively treated patients. All treatments were performed as outpatients without anesthesia; over 95 per cent of 109 treatments were performed without analgesia or sedation. Ursodeoxycholic acid was administered post-treatment. Seventy per cent of patients had multiple sessions. Cumulative stone-free rates of 38 per cent at 6 months, 65 per cent at 12 months, and 75 per cent at 15 months were achieved. There was no difference in eventual stone clearance between patients with single stones less than 20 mm diameter, single stones greater than or equal to 20 mm diameter, or multiple (two or three) stones, although patients with single smaller stones required significantly fewer total shocks to become stone-free (P = .02). Stone clearance correlated with estimated stone volume. Biliary pain occurred in 62 per cent of patients after treatment but ceased in stone-free patients. Biliary complications of pancreatitis (7.5%) and choledocholithiasis (3.8%) were successfully treated by endoscopic papillotomy. Nonbiliary complications were virtually nonexistent. Three patients (5.7%) had elective cholecystectomy. Results indicate that piezoelectric lithotripsy is a safe, minimally painful treatment that, in conjunction with oral bile acids, can produce stone-free rates of 75 to 100 per cent in selected patients.


Subject(s)
Cholelithiasis/therapy , Lithotripsy/methods , Adult , Aged , Biliary Tract Diseases/etiology , Cholelithiasis/drug therapy , Cholelithiasis/pathology , Colic/etiology , Combined Modality Therapy , Female , Follow-Up Studies , Humans , Lithotripsy/adverse effects , Male , Middle Aged , Prospective Studies , Recurrence , Ursodeoxycholic Acid/therapeutic use
8.
J Lab Clin Med ; 119(1): 99-107, 1992 Jan.
Article in English | MEDLINE | ID: mdl-1345796

ABSTRACT

Sulfasalazine is used in the treatment of chronic inflammatory states, for example, in inflammatory bowel disease and to a lesser degree in rheumatoid arthritis. In chronic inflammation, the formation of new blood vessels may play a key role in maintaining the inflammatory state. This process is dependent on the activation and proliferation of the endothelial cells. To investigate the possible role of sulfasalazine and its metabolites, sulfapyridine and 5-aminosalicylic acid, we examined the effect of these drugs on vascular endothelial cell proliferation in vitro. Cultures of bovine aortic endothelial cells were incubated with sulfasalazine and its metabolites. At 24 hours of incubation, sulfasalazine inhibited tritiated thymidine incorporation and cell proliferation and had already slowed S-phase progression at a concentration greater than 0.125 mmol/L. After 3 hours of incubation, sulfasalazine inhibition of tritiated thymidine incorporation into the DNA of endothelial cells was observed. This inhibition was completely reversible 24 hours after the drug was removed. One of the possible mechanisms for the inhibition of endothelial cell proliferation is interference with the de novo synthesis of thymidine that depends on folate-dependent enzymes. The effect of deoxyuridine and tetrahydrofolate on tritiated thymidine incorporation into cellular DNA, as well as release of tritium to water by [5-3H]-labeled deoxyuridine on methylation to thymidine, were used as probes for the de novo synthesis of thymidine. Deoxyuridine and tetrahydrofolate, when added to cells either individually or together for 3 hours, suppressed incorporation of tritiated thymidine into DNA through an increase in de novo thymidine synthesis. Sulfasalazine, but not its metabolites, reduced this suppression.2+ culture is inhibited by sulfasalazine and olsalazine but not by their metabolites. This inhibition appears to depend partly on the reduction of de novo synthesis of thymidine that is folate dependent.


Subject(s)
Cell Cycle/drug effects , Endothelium, Vascular/cytology , Sulfasalazine/pharmacology , Aminosalicylic Acids/pharmacology , Animals , Cattle , Cell Count/drug effects , Deoxyuridine/pharmacology , Mesalamine , Sulfapyridine/pharmacology , Tetrahydrofolates/pharmacology , Thymidine/antagonists & inhibitors , Thymidine/metabolism , Time Factors , Tritium
9.
Arch Intern Med ; 151(12): 2394-400, 1991 Dec.
Article in English | MEDLINE | ID: mdl-1746996

ABSTRACT

We conducted a double-blind, placebo-controlled, multicenter trial comparing the efficacy of famotidine 40 mg administered at bedtime (HS), 20 mg given twice daily (BID), and placebo to relieve heartburn and to heal endoscopically documented esophageal erosions or ulcerations. A total of 338 patients were randomized: 135 to receive famotidine 40 mg HS, 137 to receive famotidine 20 mg BID, and 66 to receive placebo. In the group given famotidine 20 mg BID, there was a significantly greater proportion of patients with complete relief of daytime heartburn, and both famotidine groups demonstrated statistically significant advantages over placebo in global scores or by successful outcome. Antacid consumption was significantly reduced in the group given famotidine 20 mg BID as compared with placebo. Both famotidine regimens resulted in a significantly greater proportion of patients with complete endoscopic healing than placebo, with the BID dosing being numerically superior to the 40-mg HS dose.


Subject(s)
Famotidine/administration & dosage , Gastroesophageal Reflux/drug therapy , Adult , Dose-Response Relationship, Drug , Double-Blind Method , Drug Administration Schedule , Esophagoscopy , Famotidine/adverse effects , Female , Gastroesophageal Reflux/complications , Gastroesophageal Reflux/pathology , Heartburn/etiology , Humans , Male , Middle Aged , Patient Compliance
11.
Article in English | MEDLINE | ID: mdl-2177899

ABSTRACT

Eicosanoids are potent mediators of inflammation and are synthesized in increased quantity in active ulcerative colitis. To elucidate the role of prostaglandin E2, thromboxane A2, prostaglandin I2, and leukotriene B2 in acute chemical colitis induced by 4% acetic acid, we utilized an animal model which has a deficiency of arachidonic acid, the precursor of eicosanoids due to an essential fatty acid deficient diet. Forty-eight hours after colitis was induced, mucosal synthesis of the cyclooxygenase products, prostaglandin E2, thromboxane A2, and prostaglandin I2, was significantly decreased in essential fatty acid deficient rats compared to normal controls. However, the 5-lipoxygenase product, leukotriene B4, was not different between groups. The decrease in cyclooxygenase products did not correlate with any change in the severity of colonic inflammation as assessed by gross morphology, histology, or myleoperoxidase activity. Thus inhibition of formation of the cyclooxygenase products of arachidonate metabolism does not appear to improve the degree of inflammation under the experimental conditions employed in this study.


Subject(s)
Colitis/metabolism , Eicosanoids/biosynthesis , Fatty Acids, Essential/deficiency , Acetates , Acetic Acid , Animals , Colitis/chemically induced , Colitis/pathology , Female , In Vitro Techniques , Intestinal Mucosa/metabolism , Leukotriene B4/biosynthesis , Prostaglandin-Endoperoxide Synthases/metabolism , Rats , Rats, Inbred Strains
12.
Postgrad Med ; 87(2): 191-4, 199-207, 1990 Feb 01.
Article in English | MEDLINE | ID: mdl-2405370

ABSTRACT

Because of the broad range of physiologic problems and the many potential sources of complications, liver transplantation patients require contributions from virtually the complete spectrum of medical science. The evolving specialty of liver transplantation has eagerly assimilated advances in surgical techniques, anesthetic agents, critical care, nutrition, immunologic manipulation, and tissue preservation. Stimulated by increasingly successful results, the public appears to have slowly accepted the expense of this labor- and technology-intense therapy. The role of workers in this area is to strive not only to improve results but also to control costs.


Subject(s)
Liver Transplantation , Graft Rejection , Humans , Immunosuppression Therapy , Liver Transplantation/methods , Postoperative Care
14.
J Lipid Res ; 30(1): 39-49, 1989 Jan.
Article in English | MEDLINE | ID: mdl-2493057

ABSTRACT

Longitudinal studies were carried out in the rabbit model to determine alterations in the concentration and density distribution of plasma lipids and apolipoproteins during the acute phase response (APR) characterized by elevated levels of C-reactive protein (CRP) and serum amyloid A (SAA). Twelve hr after the intramuscular injection of croton oil, SAA was detectable in high density lipoprotein (HDL). At the height of the response (72 hr), HDL decreased while SAA became the major HDL apoprotein, up to 80% of the proteins in the higher density fractions. The SAA-enriched particles became denser (density of HDL3) but larger (size of HDL2), had slower electrophoretic mobility, and were depleted in apoA-I, cholesterol, triglyceride, and phospholipid. HDL-cholesterol decreased and was redistributed to other fractions while apoA-I disappeared from the circulation. During this time plasma triglycerides increased 6- to 10-fold while plasma cholesterol and phospholipids showed minimal changes. ApoB increased 5- to 6-fold while the apoB-containing particles shifted to higher density resulting in elevated IDL and then LDL during recovery. VLDL (d less than 1.006 g/ml) increased and acquired 30-40% of the plasma triglycerides, cholesterol, phospholipid, and apoB. SAA also increased in VLDL while apoE decreased.


Subject(s)
Acute-Phase Reaction/blood , Apolipoproteins/blood , Inflammation/blood , Lipids/blood , Animals , Apolipoproteins B/blood , Electrophoresis, Polyacrylamide Gel , Female , Lipoproteins, LDL/blood , Lipoproteins, VLDL/blood , Phospholipids/blood , Rabbits , Serum Amyloid A Protein/analysis , Triglycerides/blood
15.
Am J Gastroenterol ; 83(11): 1220-5, 1988 Nov.
Article in English | MEDLINE | ID: mdl-3055941

ABSTRACT

Two multi-investigator, double-blind, randomized, placebo-controlled, crossover trials were conducted to determine whether tri-buffered formulations of both regular strength aspirin and extra strength aspirin would be less likely than plain aspirin to provoke subjective gastrointestinal (GI) intolerance. Each trial was divided into two phases, a qualification phase and a test phase. During the qualification phase, subjects with a history of gastrointestinal intolerance to aspirin were randomized to a double-blind crossover treatment with aspirin and placebo (325 mg aspirin per tablet in study 1 and 500 mg aspirin per tablet in study 2), two tablets four times a day for 3 days or until the occurrence of stomach upset. Subjects who reported gastrointestinal symptoms with aspirin and not with placebo qualified to participate in the test phase of the study. They were rerandomized to participate in a three-way crossover study of plain aspirin, tri-buffered aspirin, and placebo in the test phase. Tri-buffered aspirin was associated with an appreciable reduction in the incidence of gastrointestinal upset relative to plain aspirin, 34 percentage points in study 1 (p less than 0.001) and 33 percentage points in study 2 (p less than 0.001). Similar results were obtained in the evaluation of the reduction of the severity of gastrointestinal symptoms.


Subject(s)
Aspirin/adverse effects , Stomach Diseases/chemically induced , Adult , Aspirin/administration & dosage , Clinical Trials as Topic , Double-Blind Method , Female , Gases , Heartburn/chemically induced , Humans , Male , Middle Aged , Multicenter Studies as Topic , Nausea/chemically induced , Pain/chemically induced , Random Allocation , Tablets, Enteric-Coated
18.
Atherosclerosis ; 64(2-3): 147-53, 1987 Apr.
Article in English | MEDLINE | ID: mdl-3606711

ABSTRACT

Extrahepatic biliary obstruction in humans and rats leads to hypertriglyceridemia. The observed hypertriglyceridemia could result from either a defect of plasma triglyceride (TG) catabolism or hepatic over-production of TG. To examine these questions we have used the rat model to determine hepatic TG secretion by the Triton WR-1339 methodology (inhibition of peripheral lipolysis) and exogenous TG clearance (after i.v. injection of Intralipid). Four groups of rats were studied: group OB--48 h post-operative--bile-duct obstructed; group DV--bile diverted; group SC--sham-operated controls; and group FC--48 h fasted, unoperated controls. The hepatic TG secretion rate for group OB rats was a factor of 7 lower than that of either group SC or FC, and 5 times lower than that for group DV. There were no differences between the hepatic TG secretion rates of groups DV and FC or SC. After i.v. injection of Intralipid, plasma TG decreased with first-order kinetics. The rate constant was taken as the exogenous TG clearance rate (ETGCR). Mean ETGCR for group OB was a factor of 3 lower than that for either control group; while the ETGCR for group DV was equivalent to the control groups. Thus biliary diversion does not affect hepatic TG secretion or the ETGCR. The apparent cause of the hypertriglyceridemia of cholestasis in the bile-obstructed rat is impaired plasma TG catabolism.


Subject(s)
Cholestasis, Extrahepatic/metabolism , Liver/metabolism , Polyethylene Glycols/pharmacology , Triglycerides/metabolism , Animals , Cholestasis, Extrahepatic/blood , Disease Models, Animal , Liver/drug effects , Male , Rats , Rats, Inbred Strains , Triglycerides/biosynthesis , Triglycerides/blood
19.
Pharmacotherapy ; 7(6 Pt 2): 116S-119S, 1987.
Article in English | MEDLINE | ID: mdl-2895456

ABSTRACT

Epidemiologic evidence has shown that elevated levels of high-density lipoproteins (HDL) protect against the development of coronary heart disease (CHD). These observations have prompted the evaluation of various factors thought to affect HDL and its subspecies, HDL2 and HDL3. Numerous behavioral and physiologic factors have been shown to elevate HDL levels. These are currently being researched as potential tools in preventing CHD. Several pharmacologic agents are known to alter HDL levels. Studies show that patients with peptic ulcer disease treated with the H2-receptor antagonist cimetidine show significant elevations in their HDL, HDL2, and HDL3 profiles. In contrast, ranitidine has no effect, or may even decrease HDL levels. These divergent effects may be related to differences in pharmacologic activity unrelated to H2-receptor blockade. It should be noted that many of the variables affecting HDL levels were not controlled in these studies, and definite conclusions should not be extrapolated to the general population at risk for CHD. Currently, well-controlled trials to study the effect of cimetidine on HDL levels are in progress.


Subject(s)
Histamine H2 Antagonists/pharmacology , Lipoproteins, HDL/blood , Humans
20.
J Lipid Res ; 27(2): 196-207, 1986 Feb.
Article in English | MEDLINE | ID: mdl-3958622

ABSTRACT

Supplementation of high fat/cholesterol-enriched diets with polyoxypropylene-polyoxyethylene copolymers containing 90% hydrophobic constituents has been found to impair enteric secretion of chylomicrons, lower plasma levels of very low density (VLDL) and low density (LDL) lipoprotein cholesterol and prevent diet-induced hypercholesterolemia and atherosclerosis. These agents are known to be absorbed from the gastrointestinal tract and excreted in bile. In order to determine whether dietary supplementation with this group of hydrophobic poloxalenes influences hepatic secretion of triglyceride-rich lipoproteins, groups of rats were maintained for 21-34 days on either standard chow, semisynthetic diet containing 10.0% safflower oil/1.0% cholesterol, or each of the above diets supplemented with the hydrophobic poloxalene Pluronic L-81. At the end of the feeding period, newly secreted hepatic VLDL were isolated from 2-hr recirculating liver perfusates, quantitated, and characterized. Compared to perfusions in chow-fed rats, perfusion experiments in rats fed the high fat/cholesterol-enriched semisynthetic diet revealed a 3.1-fold increased net hepatic VLDL secretion rate; enrichment of secretory VLDL in cholesteryl esters and in C18:2 core lipid fatty acids; and a shift in the size distribution of secretory VLDL towards larger particles. When the 0.5% Pluronic L-81 was included in the high fat/cholesterol-enriched semisynthetic diet, the net hepatic VLDL secretion rate fell significantly and the physicochemical properties of secretory VLDL in these rats were found to resemble those of chow-fed animals. Supplementation of the chow diet with L-81 resulted in a significant fall in the net hepatic VLDL secretion rate from that observed in rats fed chow alone. Compared to rats fed chow alone, perfusate VLDL from rats fed each of the other experimental diets contained markedly lower amounts of both apoB molecular weight variants, as analyzed by gradient gel electrophoresis and densitometric gel scanning. Since previous studies have demonstrated that VLDL are the major cholesterol transport lipoproteins following fat/cholesterol feeding; a precursor-product relationship exists between fat/cholesterol-induced hepatic VLDL and plasma VLDL; such particles are capable of delivering cholesterol to the arterial wall; and dietary supplementation with hydrophobic poloxalenes prevents both the increase in plasma VLDL-cholesterol and diet-induced atherosclerosis, it is possible that dietary supplementation with hydrophobic poloxalenes may influence the atherogenic process through direct and/or indirect effects on hepatic VLDL transport.


Subject(s)
Lipoproteins, VLDL/metabolism , Liver/metabolism , Poloxalene/administration & dosage , Polyethylene Glycols/administration & dosage , Alanine Transaminase/blood , Animals , Apolipoproteins/metabolism , Diet , Electrophoresis, Polyacrylamide Gel , Fatty Acids/analysis , Growth/drug effects , Lipids/blood , Liver/drug effects , Liver/ultrastructure , Male , Particle Size , Perfusion , Poloxalene/pharmacology , Rats , Rats, Inbred Strains
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