Sex differences in long chain fatty acid utilization and fatty acid binding protein concentration in rat liver.

Female sex and estrogen administration are associated with increased hepatic production of triglyceride-rich lipoproteins; the basis for this has not been fully elucidated. Inasmuch as hepatic lipoprotein production is also influenced by FFA availability and triglyceride biosynthesis, we investigated sex differences in FFA utilization in rat hepatocyte suspensions and in the components of the triglyceride biosynthetic pathway. Isolated adult rat hepatocyte suspensions were incubated with albumin-bound [(14)C]oleate for up to 15 min. At physiological and low oleate concentrations, cells from females incorporated significantly more (14)C into glycerolipids, especially triglycerides, and into oxidation products than did male cells, per milligram cell protein. At 0.44 mM oleate, incorporation into triglycerides in female cells was approximately twice that in male cells. Comparable sex differences were observed in cells from fasted animals and when [(14)C]-glycerol incorporation was measured. At higher oleate concentrations, i.e., fatty acid:albumin mole ratios in excess of 2:1, these sex differences were no longer demonstrable, suggesting that maximal rates of fatty acid esterification and oxidation were similar in female and male cells. In female and male hepatic microsomes, specific activities of long chain acyl coenzyme A synthetase, phosphatidate phosphohydrolase, and diglyceride acyltransferase were similar, but glycerol-3-phosphate acyltransferase activity was slightly greater in females at certain substrate concentrations. Microsomal incorporation of [(14)C]oleate into total glycerolipids was not significantly greater in females. In further contrast to intact cells, microsomal incorporation of [(14)C]oleate into triglycerides, although significantly greater in female microsomes, accounted for only a small fraction of the fatty acid esterified.The binding affinity and stoichiometry of partially purified female hepatic fatty acid binding protein (FABP) were similar to those of male FABP. In contrast, the concentration of FABP, per milligram cytosolic protein, was 44% greater in female liver than in male, as indicated by measurement of [(14)C]oleate binding and of 280 nm OD in the FABP fraction of 105,000 g supernate after gel filtration chromatography. These experiments demonstrate profound sex differences in hepatocyte utilization of long chain fatty acids at concentrations within and below the physiological range, and suggest that these are attributable at least in part to corresponding differences in cytosolic FABP concentration. At higher FFA concentrations, sex differences in hepatocyte FFA utilization are virtually eliminated, suggesting that under these conditions, differences in FABP concentration are not rate determining. Sex differences in hepatic lipoprotein production may largely reflect these important differences in the initial stages of hepatocyte FFA utilization.

Sex steroid modulation of fatty acid utilization and fatty acid binding protein concentration in rat liver.

The mechanism by which sex steroids influence very low density hepatic lipoprotein triglyceride production has not been fully elucidated. In previous studies we showed that [(14)C]oleate utilization and incorporation into triglycerides were greater in hepatocyte suspensions from adult female rats than from males. The sex differences were not related to activities of the enzymes of triglyceride biosynthesis, whereas fatty acid binding protein (FABP) concentration in liver cytosol was greater in females. These findings suggested that sex differences in lipoprotein could reflect a sex steroid influence on the availability of fatty acids for hepatocellular triglyceride biosynthesis. In the present studies, sex steroid effects on hepatocyte [(14)C]oleate utilization and FABP concentration were investigated directly. Hepatocytes from immature (30-d-old) rats exhibited no sex differences in [(14)C]oleate utilization. With maturation, total [(14)C]oleate utilization and triglyceride biosynthesis increased moderately in female cells and decreased markedly in male cells; the profound sex differences in adults were maximal by age 60 d. Fatty acid oxidation was little affected. Rats were castrated at age 30 d, and received estradiol, testosterone, or no hormone until age 60 d, when hepatocyte [(14)C]oleate utilization was studied. Castration virtually eliminated maturational changes and blunted the sex differences in adults. Estradiol or testosterone largely reproduced the appropriate adult pattern of [(14)C]oleate utilization regardless of the genotypic sex of the treated animal. In immature females and males, total cytosolic FABP concentrations were similar. In 60-d-old animals, there was a striking correlation among all groups (females, males, castrates, and hormone-treated) between mean cytosolic FABP concentration on the one hand, and mean total [(14)C]oleate utilization (r = 0.91) and incorporation into triglycerides (r = 0.94) on the other. In 30-d-old animals rates of [(14)C]oleate utilization were greater, relative to FABP concentrations, than in 60-d-old animals. The sex differences that characterize fatty acid utilization in adult rat hepatocytes are not present in cells from immature animals, and reflect in part the influence of sex steroids. It remains to be determined whether the observed relationship of hepatic FABP concentration to [(14)C]oleate utilization in adult cells is causal or secondary to changes in cellular fatty acid uptake effected through another mechanism. In either case, modulation of triglyceride-rich lipoprotein production by six steroids appears to be mediated to a significant extent by their effects on hepatic fatty acid utilization.

Expression of blood group-related antigens ABH, Lewis A, Lewis B, Lewis X, Lewis Y, and CA 19-9 in pancreatic cancer cells in comparison with the patient's blood group type.

Blood group A, B, H, Le, Leb, Lex, and Ley antigenicity as well as the expression of CA 19-9 were examined in pancreatic cancer specimens from 30 patients, using monoclonal antibodies to the respective antigen and immunohistochemical techniques, and the findings were correlated with the blood group types (ABO and Lewis) of the individuals. Compatible antigen expression was found in 82, 75, and 50% of tumors from patients with A, B, and O blood group types, respectively. Deletion of the compatible antigen was found in 10 (33%) of the cases, predominantly in patients of blood group O type, and incompatible expression (of B antigen only) in 4 (13%). Lea was detected in 87%, Leb in 90%, Lex in 30%, and Ley in 43% of the specimens, regardless of ABH and Lewis phenotype of the patients. Coexpression of Lea and Leb was found in 87%, of Lex and Ley in 13%, of Lea and Lex in 23%, and of Leb and Ley in 40% of the cases. CA 19-9 was expressed in 80% of the tumors; it was present in the tumor tissue of 21 of 22 patients from Lea-b+, in all 4 individuals from Lea+b-, but in none of the 4 patients from Lea-b- phenotype (P less than 0.01). Heterogeneity in the expression of each of the antigens was found. The overall results indicate that blood group antigen expression in pancreatic tumor differs from that of other gastrointestinal cancers and that the Lewis antigen expression in pancreatic cancer cells is independent of the blood group phenotype of the patients and thus may be useful as a tumor marker.

Correlative study on expression of CA 19-9 and DU-PAN-2 in tumor tissue and in serum of pancreatic cancer patients.

The serum levels of CA 19-9 and DU-PAN-2 antigens and their expression in tumor tissue were examined in 22 pancreatic cancer patients and the results were correlated with the Lewis (Le) blood group phenotypes of the individuals. In tumor tissue, CA 19-9 was expressed in 17 of 22 (77%) specimens. The negative cases included three patients with Lea-b-, one with Lea+b- and the other with Lea-b+ phenotypes. DU-PAN-2 antigen was expressed in 20 of 22 (91%) cancer tissues. The two DU-PAN-2-negative cases were CA 19-9-positive. The combination of two markers increased the sensitivity to 100%. In the serum, CA 19-9 level was elevated (greater than 37 U/ml) in 16 of 21 (73%) cases. All Lea-b- patients had values less than 37 U/ml. An elevated level of DU-PAN-2 (greater than 300 U/ml) was detected in 14 of 21 (67%) patients including three cases with Lea-b- type. In only one patient were both antigens below the cutoff levels so that the combination of two biomarkers elevated the sensitivity to 95%. The study indicated that the cocktail of 19-9 and DU-PAN-2 antibodies might increase the sensitivity and specificity for clinical diagnosis of pancreatic cancer. In 19 of 21 (90%) cases, the serum CA 19-9 level correlated with the expression of the antigen in the cancer tissue. Discrepancy was seen in two cases; one patient had an elevated level of CA 19-9 in the serum, but lacked this antigen in the cancer cells. In the second case, the situation was reversed. For DU-PAN-2, positive correlation was seen in 14 of 21 (67%) cases. Six of seven patients with low DU-PAN-2 levels expressed the antigen in their tumor cells, and one patient with DU-PAN-2-negative cancer tissue had an elevated level of this marker in the serum. Thus, CA 19-9 expression in serum corresponded more closely to expression in tissue than did that of DU-PAN-2 antigen. The serum levels of these antigens, however, is likely due to multiple factors, only one of which is the qualitative and quantitative expression of the antigens in tumors.

Relationship of carbohydrate antigen 19-9 and Lewis antigens in pancreatic cancer.

Carbohydrate antigen (CA) 19-9 identified by a murine monoclonal antibody against a colorectal carcinoma antigen is thought to be a sialylated Lewis (Le)a blood group antigen and occurs in high concentration in serum of patients with pancreatic carcinoma. This study was designed to identify the relationship between Lewis antigens and CA 19-9 in patients with pancreatic cancer. The following analyses were performed in 20 pancreatic cancer patients: Lea and Leb antigen phenotype in saliva (modified enzyme-linked immunosorbent assay) or on red cells (hemagglutination); CA 19-9 levels (radioimmunoassay) in serum; and CA 19-9 and Lea and Leb expression (immunoperoxidase assay) on tumor tissue. Lea-b- patients based on salivary phenotype failed to express CA 19-9 in tumor tissue and had normal or low levels of CA 19-9 (less than 37 units/ml) in serum (P = 0.0011, versus Lea+b- and Lea-b+ patients). Eighty-eight % of Lea+b- and Lea-b+ patients had elevated serum CA 19-9 levels (greater than 37 units/ml). All Lea+b- and Lea-b+ patients expressed both Lea and Leb antigens in tumor tissue. These results support the view that Lea-b- pancreatic cancer patients cannot manufacture CA 19-9. Surprisingly, Lea-positive patients express Leb antigen in tumor tissue; in this subgroup, Leb antigen may be a tumor-specific biomarker.

Evaluation of ondansetron prescribing in US academic medical centers.

BACKGROUND: The study objectives were to characterize the use of the antiemetic ondansetron, a serotonin subtype 3 receptor antagonist, in US academic medical centers, and to assess ondansetron prescribing with consensus-derived prescribing guidelines used as evaluation criteria. METHODS: A multicenter, prospective, observational study was conducted in the inpatient and outpatient care areas of 23 US academic medical centers. A total of 670 patients received ondansetron (508 inpatients and 162 outpatients). The use of ondansetron was compared with consensus-derived prescribing guidelines on the basis of indication for use and dose administered. RESULTS: Only 253 (37.8%) of the 670 patients satisfied for prescribing guidelines for both indication for use and dose administered. The remainder of the patients did not satisfy the guidelines, in whole or in part. If all ondansetron use had met the prescribing guidelines in the patients studied, a reduction in ondansetron use of 31% (16 185/52 260 mg) would have been realized. At an estimated cost of $5 per milligram, this reduction represents a potential cost savings of nearly $81,000, or $121 per patient studied. CONCLUSION: Since its introduction in 1991, ondansetron has become a commonly used antiemetic in US academic medical centers. Although ondansetron is safe and effective in improving patients' tolerance of emetogenic therapies, including cancer chemotherapy, its high cost has added a significant burden to the pharmaceutical budgets of many institutions. The study data suggest that compliance with ondansetron prescribing guidelines, with elimination of indiscriminant use, could result in significant cost savings.

Albumin and nonprotein colloid solution use in US academic health centers.

BACKGROUND: Crystalloids, nonprotein colloids (NPCs), and albumin are used for many indications. The use of the least costly agent in situations where these products are clinically interchangeable can reduce health care costs. OBJECTIVES: To characterize the prescribing of albumin and NPC. To evaluate the appropriateness and cost implications of their use. METHODS: An observational study conducted in 15 academic health centers from April 11 through May 6, 1994, to assess the appropriateness of albumin and NPC use, based on "model" consensus-derived indication guidelines. RESULTS: A total of 969 case report forms were evaluated. Albumin and NPCs were administered in 83% and 17% of the cases, respectively. Albumin and NPCs were administered mostly in the intensive care (50%) or operating room (31%) settings. The most common prescribers of these products were surgeons (45%) and anesthesiologists (20%). In 87% of cases, albumin or NPC was administered to reach a defined end point (eg, to achieve a target physiological state or to resolve a pathophysiological condition). Only one albumin recipient experienced an adverse event; no adverse events were noted with NPC administration. Approximately $203,000 was spent on albumin and NPC therapy for the 969 cases; $49,702 (24%) was spent on appropriate administrations, $124,939 (62%) on inappropriate administrations, and $28,014 (14%) on unevaluated indications. CONCLUSIONS: Evaluated against model guidelines, most of the albumin and NPC use in the study was found to be inappropriate. The need for institutions to define and implement guidelines that focus on the cost-efficient use of these agents is recommended in an increasingly cost-conscious health care environment.

Paradoxical urinary excretion of D-glucaric acid in acute viral hepatitis.

The urinary excretion of D-glucaric acid and the plasma clearance of antipyrine were estimated during the acute phase of viral hepatitis and again during recovery. The plasma clearance of antipyrine was impaired during the acute stage of hepatitis, while the urinary excretion of D-glucaric acid was paradoxically high. Both parameters returned to normal during recovery. These findings suggest that the use of urinary D-glucaric acid excretion as an index of microsomal enzyme induction is unreliable when there is liver injury.

Hypocholesterolemic activity of a novel inhibitor of cholesterol absorption, SCH 48461.

The amount of cholesterol that circulates in the plasma as lipoproteins can be affected by the balance of cholesterol metabolism within and between the intestines and liver. In the present report, we describe a novel hypocholesterolemic agent and document its pharmacological effects in animal models of hypercholesterolemia. The oral administration of (3R,4S)-1,4-bis-(4-methoxyphenyl)-3-(3-phenylpropyl)-2-azetidinone (SCH 48461) reduced plasma cholesterol concentrations in cholesterol-fed hamsters, rats and rhesus monkeys with ED50s of 1, 2 and 0.2 mg/kg per day, respectively, SCH 48461 was also highly effective in reducing hepatic cholesteryl ester accumulation in cholesterol-fed hamsters and rats after 7 days of treatment. In one 3 week study, rhesus monkeys were fed a 0.25% cholesterol/22% saturated fat diet with or without SCH 48461. At the end of the 3 week period the control group's VLDL + LDL-cholesterol increased to 180 Mg/dl from a baseline of approximately 65 mg/dl while plasma apolipoprotein B levels had doubled. Animals treated daily with 1 mg/kg SCH 48461 maintained their baseline levels of VLDL + LDL-cholesterol, HDL-cholesterol, and plasma apolipoproteins B and A-I. After 3 weeks the diets of the two groups were switched. Within 1 week SCH 48461 (1 mg/kg per day) rapidly reversed the elevated VLDL + LDL-cholesterol levels of the previous control group to near baseline values. SCH 48461 exerted its hypocholesterolemic effect through the inhibition of cholesterol absorption. A dose of 10 mg/kg per day inhibited cholesterol absorption in cholesterol-fed hamsters by 68% while a similar reduction was achieved in chow-fed monkeys with 3 mg/kg per day. This latter dose inhibited cholesterol absorption in cholesterol-fed monkeys by 95%. Treatment of cholesterol-fed monkeys with 10 mg/kg per day SCH 48461 significantly increased fecal neutral sterol excretion (52 vs. 32 mg/kg) but had no effect on acidic sterol excretion. Using a 2-h absorption model in cholesterol-fed hamsters, SCH 48461 caused a 46% inhibition of unesterified [14C]cholesterol accumulation in the intestinal wall and a 90% inhibition of cholesteryl ester formation at a dose of 10 mg/kg. Similar data were observed when the plasma radioactivity was assessed, indicating inhibition of both free (61%) and esterified (85%) cholesterol appearance. In contrast, CI-976, a potent acyl-CoA:cholesterol acyltransferase (ACAT) inhibitor, did not affect the uptake of free cholesterol into the intestines while inhibiting cholesterol esterification (98% inhibition).(ABSTRACT TRUNCATED AT 400 WORDS)

Discovery of 1-(4-fluorophenyl)-(3R)-[3-(4-fluorophenyl)-(3S)-hydroxypropyl]-(4S)-(4 -hydroxyphenyl)-2-azetidinone (SCH 58235): a designed, potent, orally active inhibitor of cholesterol absorption.

(3R)-(3-Phenylpropyl)-1,(4S)-bis(4-methoxyphenyl)-2-azetidinone (2, SCH 48461), a novel inhibitor of intestinal cholesterol absorption, has recently been described by Burnett et al. and has been demonstrated to lower total plasma cholesterol in man. The potential sites of metabolism of 2 were considered, and the most probable metabolites were prepared. The oral cholesterol-lowering efficacy of the putative metabolites was evaluated in a 7-day cholesterol-fed hamster model for the reduction of serum total cholesterol and liver cholesteryl esters versus control. On the basis of our analysis of the putative metabolite structure-activity relationship (SAR), SCH 58235 (1, 1-(4-fluorophenyl)-(3R)-[3-(4-fluorophenyl)-(3S)-hydroxypropyl]-(4S)- (4-hydroxyphenyl)-2-azetidinone) was designed to exploit activity enhancing oxidation and to block sites of potential detrimental metabolic oxidation. Additionally, a series of congeners of 2 were prepared incorporating strategically placed hydroxyl groups and fluorine atoms to further probe the SAR of 2-azetidinone cholesterol absorption inhibitors. Through the SAR analysis of a series of putative metabolites of 2, compound 1 was targeted and found to exhibit remarkable efficacy with an ED50 of 0.04 mg/kg/day for the reduction of liver cholesteryl esters in a 7-day cholesterol-fed hamster model.

2-Azetidinone cholesterol absorption inhibitors: structure-activity relationships on the heterocyclic nucleus.

A series of azetidinone cholesterol absorption inhibitors related to SCH 48461 ((-)-6) has been prepared, and compounds were evaluated for their ability to inhibit hepatic cholesteryl ester formation in a cholesterol-fed hamster model. Although originally designed as acyl CoA: cholesterol acyltransferase (ACAT) inhibitors, comparison of in vivo potency with in vitro activity in a microsomal ACAT assay indicates no correlation between activity in these two models. The molecular mechanism by which these compounds inhibit cholesterol absorption is unknown. Despite this limitation, examination of the in vivo activity of a range of compounds has revealed clear structure-activity relationships consistent with a well-defined molecular target. The details of these structure-activity relationships and their implications on the nature of the putative pharmacophore are discussed.

Diagnosis and treatment of biliary tract complications after orthotopic liver transplantation.

Biliary tract complications are a continuing source of morbidity after liver transplantation. In a 3.5-year period we performed 264 liver transplants in 226 patients (132 adults, 94 children). Biliary tract reconstruction was via Roux limb choledochojejunostomy (n = 144) or choledochocholedochostomy (n = 118). Fifty (19.1%) biliary complications occurred, and 35 (13.4%) necessitated operative repair. The incidence was similar in adults and children and after each method of reconstruction. Risk factors were vascular thrombosis and reduced-sized transplants. Diagnosis was based on the algorithmic use of multiple modalities with early biliary visualization. Roux limb complications usually occurred in the first month after transplant and necessitated operative intervention, whereas duct-to-duct problems appeared later and were more accessible to percutaneous or endoscopic manipulations. Eight (6.8%) patients required conversion to a Roux limb, whereas 8/15 (53.3%) cases of biliary stricture were successfully managed nonoperatively. Three (1.3%) patients and four (1.5%) grafts were lost as a result of biliary complications. One-year actuarial patient survival is 76.4% with a mean follow-up of 13.2 months. Early recognition of biliary complications and prompt interventional therapy can effectively prevent long-term sequelae. Although choledochocholedochostomy is more physiologic and expeditious, Roux-en-Y choledochojejunostomy remains a safe and versatile alternative and is the preferred method of reconstruction in select cases.

The many uses of the U tube.

U tube placement was employed as an adjunct to complicated biliary procedures in 14 patients. We found the transhepatic tubes to be useful for stenting biliary anastomoses, maintaining biliary drainage, delivering localized irradiation, and acting as permanent external conduits. The tubes remained in placed an average of 15 months and as long as 40 months. The frequency of cholangitis was minimized by frequent tube exchange. The U-shaped configuration makes tube exchange easy and inexpensive to perform.

The role of nontransplant procedures for sclerosing cholangitis.

Twenty-five of 38 patients with sclerosing cholangitis underwent operative therapy at our institution. Seven patients with primarily extrahepatic obstruction had biliary bypass procedures and maintained normal liver function for 1 to 96 months. Biliary procedures were performed in 11 patients with combined intrahepatic and extrahepatic disease. Seven patients underwent subsequent liver transplantation because of deteriorating hepatic function, and two patients died before transplantation could be performed. Although there were no significant differences in outcome of liver transplantation whether or not a biliary procedure had been performed previously, previous biliary tract procedures influenced the type of biliary reconstruction performed, and two complications occurred as direct results of prior operations. Nontransplant procedures should be restricted to those patients with primarily extrahepatic obstruction, whereas liver transplantation should be considered the initial procedure of choice for patients with diffuse sclerosing cholangitis.

Shunt surgery versus endoscopic sclerotherapy for variceal hemorrhage: late results of a randomized trial.

Between September 1982 and April 1988, 60 cirrhotic patients with prior variceal hemorrhage were randomized to undergo the placement of an elective shunt (distal splenorenal: 26; nonselective: 4) or long-term endoscopic sclerotherapy (n = 30). Eighty-six percent of patients had alcoholic cirrhosis, and 33% were classified as Child's class C. After a mean follow-up of 87 months, 60% of patients undergoing sclerotherapy and 17% of shunt patients experienced rebleeding (p < 0.001). Shunt patients have survived longer than those who had sclerotherapy (6-year survival rates of 53% and 26%, respectively; p < 0.05). In part because of the wide geographic distribution of patients, only 4 of 13 patients in whom sclerotherapy failed (31%) could undergo salvage by shunt surgery. Although hepatic portal perfusion was better maintained after sclerotherapy, there were no major differences between the groups in terms of post-therapy hepatic or psychoneurologic function. In a predominantly alcoholic cirrhotic patient population (half non-urban), the results of elective shunt surgery were superior to those of chronic endoscopic sclerotherapy with respect to the prevention of recurrent variceal hemorrhage and survival.

Increased incidence of pancreas-related complications in patients with postoperative pancreatitis.

The incidence and significance of pancreas-related complications (pseudocysts, abscesses, and fistulas) were evaluated in 100 patients with acute pancreatitis. Alcoholic (40 percent), biliary (20 percent), and postoperative (15 percent) pancreatitis were seen most frequently. Eighteen patients had severe pancreatitis (3 or more Ranson's criteria). The overall mortality rate was 8 percent, and there were 16 pancreas-related complications. Pancreas-related complications developed in eight patients (53 percent), including two pseudocysts, four abscesses, and two fistulas. The incidence of pancreas-related complications was significantly greater in the postoperative group than in the overall 9 percent incidence in the other groups (p less than 0.005). Half of these patients required operation for their complications. Patients with postoperative pancreatitis are at a markedly increased risk of pancreas-related complications. Since these complications occur even in apparently mild cases of pancreatitis, these patients should be followed closely to detect pancreas-related complications.

Nonoperative emergency treatment of variceal hemorrhage.

The nonoperative management of acute variceal hemorrhage can control acute hemorrhage and allow stabilization of the patient prior to definitive therapy to prevent further bleeding episodes. Balloon tamponade, endoscopic sclerotherapy, and pharmacotherapy can stop acute variceal bleeding. Endoscopic sclerotherapy has the highest reported success rate, decreases the incidence of early rebleeding, and is the recommended first method to control bleeding.

The rigors and rewards of clinical evaluation in an alliance of academic health systems.

The University HealthSystem Consortium (UHC), a 70-member alliance of academic health centers, was established in 1984 to help its members improve clinical practice and to strengthen their competitive position in the health care market. This article describes the programs of the UHC's Clinical Practice Advancement Center and its progress to date in promoting strategies to control cost, demonstrate value, and improve health care quality.

Clinical evaluation units: a research agenda.

A new model for evaluating quality rests on the tripod of outcomes research, practice pattern analysis, and the tenets of continuous quality improvement. The hospital-based locus for this tripod could be clinical evaluation units. This article describes the conceptual framework, study design, and research challenges associated with an ongoing project whose purpose is to assess the current status of these clinical evaluation units in academic medical centers nationwide.