Biomedical subjects

R L Conter

Publications and source records attributed to R L Conter.

23 records · Page 2Linked to original sources

PubMed1986

Gallbladder absorption increases during early cholesterol gallstone formation.

The hypothesis that the presence of cholelithogenic bile during the early stages of cholesterol gallstone formation promotes gallbladder absorption of water and electrolytes was tested in a prairie dog gallstone model. An increase in gallbladder transport of water and sodium was observed in cholesterol-fed prairie dogs at a time when cholesterol crystals were present, but before gallstone formation. These data suggest that in the presence of cholesterol-saturated bile, in vivo gallbladder absorption is increased during the early stages of cholesterol gallstone formation. The resulting increase in the solute concentration may promote nucleation and, therefore, be an important etiologic factor in cholesterol gallstone formation.

Absorption↗

PubMed1986

Carbohydrate diet-induced calcium bilirubinate sludge and pigment gallstones in the prairie dog.

Epidemiologic studies suggest that consumption of diets rich in carbohydrates may, in part, be responsible for the increasing incidence of pigment gallstone disease. The mechanism by which these dietary components lead to pigment stone formation remains obscure. Furthermore, investigative efforts in this area have been hampered by the lack of a suitable animal model. The present study was undertaken to study the role of complex carbohydrates in pigment gallstone formation in the prairie dog. Two groups of eight animals each were maintained on either a control, nonlithogenic chow, or a high carbohydrate (35% sucrose, 32% rich starch) diet for 2 months. Neither crystals nor gallstones were observed in any of the control animals. All of the carbohydrate fed animals (P less than 0.005 vs control) had calcium bilirubinate crystals and sludge, while microscopic, black stones were present in six of these eight animals (P less than 0.05 vs control). Although hepatic bile bilirubin was unchanged in the carbohydrate-fed group, these animals had a significant increase in hepatic bile calcium (P less than 0.005) and phospholipids (P less than 0.005) when compared to controls. Carbohydrate-fed animals also had a significant increase in gallbladder bile concentrations of phospholipids (P less than 0.001), calcium (P less than 0.001), unconjugated (P less than 0.005), conjugated (P less than 0.005), and total bilirubin (P less than 0.001) as compared to controls. These data indicate that in the prairie dog, carbohydrate feeding results in increased biliary concentrations of phospholipids, calcium and bilirubin, and formation of calcium bilirubinate crystals, sludge and microscopic gallstones.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1986

Enhanced gallbladder absorption during gallstone formation: the roles of cholesterol saturated bile and gallbladder stasis.

Cholesterol saturated bile and gallbladder stasis are important factors in the pathogenesis of cholesterol gallstones. The degree to which either or both of these factors affect gallbladder transport of fluid remains obscure. The authors tested the hypothesis that both cholesterol saturated bile and gallbladder stasis, and not stasis alone, promotes gallbladder fluid absorption. Prairie dogs were maintained for 2 weeks on either a control chow, total parenteral nutrition (TPN), or a 1.2% cholesterol enriched chow. The bile acid pool was labeled with 14C-cholic acid and indexes for cholesterol saturation (CSI) and gallbladder stasis (Rsa) were determined. Fluid transport was indirectly measured by calculating the ratio of gallbladder to hepatic bile concentrations of individual and total biliary lipids. Despite evidence of stasis in prairie dogs maintained on TPN, bile was unsaturated, and gallbladder absorption was not appreciably changed. In contrast, cholesterol-fed animals had cholesterol supersaturated bile, gallbladder stasis, and altered gallbladder absorption, as manifested by a significant change in the ratio of gallbladder to hepatic bile concentrations of individual and total biliary lipids. These data suggest that both cholesterol saturated bile and gallbladder stasis, and not stasis alone, are essential in promoting the enhanced gallbladder absorption, which has previously been observed during early cholesterol gallstone formation.

Absorption↗

PubMed1986

In vivo gallbladder absorption: a new dual-isotope technique.

Available methods for measuring in vivo gallbladder absorption preclude the use of animals in which hepatic bile enters the gallbladder via accessory or aberrant channels. However, accessory bile ducts are present in many of the animal models currently used in gallstone research. The aim of this study, therefore, was to evaluate a new dual-isotope technique that corrects for accessory bile flow and to compare data on electrolyte and water absorption with those derived from the standard, single-isotope technique. Prairie dogs underwent gallbladder exclusion by cystic duct ligation and common bile duct cannulation. Carbon 14-polyethylene glycol-labeled lactated Ringer's solution was instilled into the gallbladder while tritiated cholic acid was administered intravenously to label the bile acid pool. There is no correlation between water or electrolyte absorption and time, nor between water and electrolyte absorption, when these parameters are calculated by the standard, single-isotope technique. In contrast, use of the dual-isotope technique quantifies accessory bile duct flow and yields a linear increase in water and electrolyte absorption, both of which are time dependent. These data suggest that the dual-isotope technique provides a means to accurately measure in vivo gallbladder absorption in animals with or without accessory bile ducts.

Absorption↗

PubMed1986

Differentiation of pyogenic from amebic hepatic abscesses.

Recent immigration trends have resulted in an increased prevalence of amebic hepatic abscesses in southern states and in many northern American cities. Because amebic hepatic abscesses generally do not require drainage, differentiation from pyogenic hepatic abscesses is important. We, therefore, reviewed the records of patients admitted to the UCLA Medical Center from 1968 through 1983 to compare the clinical manifestations and to access the results of treatment of pyogenic and amebic hepatic abscesses. During this 15 year period, 82 patients (42 pyogenic and 40 amebic) with hepatic abscesses were admitted. Factors which distinguished patients with pyogenic abscesses included: age greater than 50 years; jaundice; pruritus; sepsis and shock; a palpable mass; elevated bilirubin level; elevated alkaline phosphatase level, and abnormal abdominal roentgenograms. Patients with amebic abscesses of the liver were more likely to have Mexican ancestry, recently traveled to an endemic area, abdominal pain, diarrhea, abdominal tenderness, hepatomegaly and positive amebic serology. Hepatic scans and ultrasonography were excellent methods of detecting the presence of but not the type of hepatic abscess. Over-all, the mortality was 40 per cent for patients with pyogenic abscesses whereas all 40 of the patients with an amebic abscess survived. However, operative mortality was only 4.5 per cent for the 22 patients with pyogenic abscess who were managed with systemic antibiotics and surgical drainage. We conclude that many clinical and laboratory parameters can aid in the differentiation and, as a result, management of patients with pyogenic and amebic hepatic abscesses.

Adolescent↗