Comparative study of the effects of short- and long-term ethanol treatment and alcohol withdrawal on phospholipid biosynthesis in rat hepatocytes

This study describes the effects of short- and long-term ethanol treatment and withdrawal on the biosynthesis of the phospholipids phosphatidylcholine (PC) and phosphatidylethanolamine (PE) in hepatocytes isolated from rats, using isotopically labelled choline and ethanolamine as exogenous precursors. Our results demonstrate that short-term ethanol consumption increases the incorporation of exogenous polar bases into PC and PE, whereas long-term ethanol administration provokes a differential effect in both PC and PE biosynthesis via cytidine diphosphate derivatives (CDP-derivatives), decreasing PC synthesis and increasing the biosynthesis of PE. We suggest that the increased biosynthesis of PE after ethanol treatment results from changes in lipogenic substrates produced as a consequence of ethanol metabolism, whilst the specific inhibition of PC biosynthesis seems to be a consequence of alterations of enzymes involved in the CDP-choline pathway. With regard to the influence of ethanol on PE methylation to give PC, our results demonstrate that ethanol activates this pathway in short-term, as well as chronic ethanol treatment. Ethanol withdrawal returns the activity of the PC and PE pathways to control levels. The alterations in the biosynthesis of the main phospholipids, PC and PE, demonstrated in this study could be of a great physiological interest in determining the pathology of alcoholism.

[Increased bile lithogenicity after simultaneous total parenteral nutrition and octrotide. A model of calcium palmitate Gallstones]

Gallbladder stasis and gallstone formation are well-known complications of both fasting-associated total parenteral nutrition (TPN) and long-term treatment with octreotide. Additive noxious effects to hepatobiliary function may develop when both therapies are given together as treatment of enteric fistulae. The aim of this study was to assess the risk of gallstone formation during treatment with TPN and octreotide separately and in combination. We studied four groups of New Zealand rabbits (n = 32) during a 2-week intervention period: 14 chow-fed controls; 6 fasted and TPN-fed; 6 chow-fed and administered octreotide, and 6 fasted and treated with both TPN and octreotide. After treatment, the bile duct was cannulated and the gallbladder and liver tissue were obtained for histological analysis. Hepatic and gallbladder bile were retrieved for microscopic examination and measurement of biliary lipids, bilirubin, calcium, total protein, and cholesterol nucleation time. The chemical composition of gallstones was also analyzed. The results of the study suggest that simultaneous administration of these two therapies in rabbits has additive effects on gallbladder stasis and bile lithogenicity. The administration of both treatments can play an important role in the formation of calcium palmitate gallstones in these animals.

Chronic ingestion of ethanol stimulates lipogenic response in rat hepatocytes

We isolated hepatocytes from rats chronically fed with ethanol and pair-fed control rats and incubated them both in the presence and absence of 100 mM ethanol in order to analyze the uptake into their lipids of several radiolabeled exogenous substrates. The hepatocytes treated chronically with ethanol showed higher lipogenic activity both in neutral lipids and phospholipids from serine, ethanolamine, glycerol and oleate. The only exception found was in the incorporation of choline into phosphatidylcholine (PC), which was lower in the hepatocytes from ethanol-fed rats than in the controls and was concomitant with a decrease in the PC levels of the ethanol-fed hepatocytes. The results obtained after exposing the cells to 100 mM ethanol in vitro indicate that in general the hepatocytes from ethanol-fed rats exhibit a higher lipogenic activity than the control cells. The only difference in the response to ethanol in vitro was found in the biosynthesis of phosphatidylserine (PS) from serine, which rose significantly in control cells but was unaffected in alcoholic hepatocytes. We put this difference in response down to specific adaptation to ethanol feeding.

Modulation of biosynthesis of phosphatidylcholine via CDP-choline in rat liver: influence of ethanol on the microsomal cholinephosphotransferase activity

We have studied in vitro the effects of ethanol on the different enzymes involved in the biosynthesis of phosphatidylcholine (PC) via CDP-choline. Ethanol alters neither choline kinase (CK) nor CTP:phosphocholine cytidylyltransferase (CT) activities but, at levels higher than 50 mM, it does significantly inhibit microsomal cholinephosphotransferase (CPT) activity concomitantly with an increase in the ethanol concentration. A study of the kinetics of the reaction catalysed by CPT shows that ethanol decreases Vmax without altering Km, indicating a non-competitive inhibitory effect. An analysis of the thermodependence of CPT activity in the absence of ethanol reveals a break in the Arrhenius plot and thus a straight relationship between enzyme activity and the physico-chemical state of the microsomal membrane. Incubation of microsomes in the presence of ethanol increased the transition temperature from 25.8-28.2 degrees C. Microsomes were also incubated with n-alkanols with chain-lengths of fewer than five carbon atoms at concentrations which, according to their partition coefficients, produce equimolar levels in the membrane. Under these conditions all the alkanols caused the same inhibitory effect. All these results demonstrate that ethanol modulate the PC biosynthesis at the level of CPT activity and does not affect the CT enzyme. The inhibition found on CPT is clearly dependent on the alteration produced by ethanol on the hepatic microsomal membrane.

Must ERCP Be routinely performed if choledocholithiasis is suspected?

OBJECTIVE

To evaluate the results of preoperative endoscopic retrograde cholangiopancreatography (ERCP) in the diagnosis and treatment of those patients suspected of harboring bile duct stones before laparoscopic cholecystectomy (LC).

PATIENTS AND METHODS

A total of 1,235 consecutive LCs performed between 1991 and 1997 were studied prospectively. ERCP was performed to explore the common bile duct (CBD) preoperatively when choledocholithiasis was suspected on the basis of clinical, analytical or echographical data.

RESULTS

ERCPs were performed in 268 patients: unsuccessful CBD evaluation in 3%; dilated CBD without lithiasis in 13%, and normal exploration in 37% (99 patients). CBD stones were found in 46% (124 patients), and endoscopic sphincterotomy was then performed and stone extraction attempted. Endoscopic therapy achieved 92.8% successful removal of CBD stones (115 patients). There was no ERCP-related mortality and the morbidity rate was 6%. Retained CBD stones have been observed in 7 cases after ERCP-LC; all of them have been successfully treated by ERCP.

CONCLUSIONS

A combined approach to bile duct stones with selective use of ERCP followed by LC is a good therapeutical alternative. Nevertheless, the usual selection criteria for ERCP may lead to unnecessary exploration. It appears to be necessary to modify the current diagnostic and therapeutic strategy.

Treatment options for villous adenoma of the ampulla of Vater

INTRODUCTION

Duodenal villous adenoma arising from the ampulla of Vater has a high risk of malignant development. Excluding associated malignant disease prior to resection of an adenoma of the ampulla is not always possible. Therefore, the surgical procedure of choice to treat this rare tumour is still controversial.

OBJECTIVE

To evaluate retrospectively results of treatment of villous adenoma arising from ampulla of Vater with dysplasia or associated carcinoma limited to the ampulla.

PATIENTS AND METHODS

From 1985 to 1996, eight patients have been diagnosed with ampullary villous adenoma suitable for resection. We have reviewed treatment, morbidity, mortality, follow-up and final outcome.

RESULTS

Pancreatoduodenectomy (PD) was performed in 4 patients. Transduodenal ampullectomy and endoscopic resection was performed in 2 patients each. There was no perioperative mortality. None of the patients had biliary, pancreatic or intestinal leakage but two patients who underwent PD had minor postoperative complications. The mean follow-up was 44 (range: 6-132) months. Villous adenoma was associated with adenocarcinoma in 50% of the cases (4/8 patients). During the follow-up both patients who underwent transduodenal ampullectomy developed recurrent disease. All patients initially treated by PD are alive without evidence of recurrent disease.

CONCLUSIONS

Treatment of villous adenoma of the ampulla must be individualized within certain limits. In our series, PD achieve good results and it appears to be the procedure of choice in order to treat villous adenomas with proved presence of carcinoma, carcinoma in situ or severe dysplasia. Endoscopic or local resection may be appropriate for small benign tumours in high risk patients.

Does trait coping exist? A momentary assessment approach to the evaluation of traits

This study investigated the extent to which momentary reports of coping are a traitlike phenomenon and the validity of a questionnaire assessment of coping style. Participants (N = 96) completed the questionnaire, then monitored stressful events and coping activities for 2 days using a hand-held computer that administered a brief assessment every 40 min. Momentary reports exhibited a sizable traitlike component: Individual differences accounted for 42% of the variance for 2 coping items and 15-30% of the variance for 15 items. The questionnaire assessment of coping style was a poor predictor of average momentary coping; the coping style measure and the aggregated momentary measure of trait coping shared 23% of their variance for religion and 0-12% for the 16 other coping measures. Self-report assessments of trait coping are poor measures of the trait component of momentary coping and very poor predictors of coping in specific situations.

Does trait coping exist? A momentary assessment approach to the evaluation of traits

This study investigated the extent to which momentary reports of coping are a traitlike phenomenon and the validity of a questionnaire assessment of coping style. Participants (N = 96) completed the questionnaire, then monitored stressful events and coping activities for 2 days using a hand-held computer that administered a brief assessment every 40 min. Momentary reports exhibited a sizable traitlike component: Individual differences accounted for 42% of the variance for 2 coping items and 15-30% of the variance for 15 items. The questionnaire assessment of coping style was a poor predictor of average momentary coping; the coping style measure and the aggregated momentary measure of trait coping shared 23% of their variance for religion and 0-12% for the 16 other coping measures. Self-report assessments of trait coping are poor measures of the trait component of momentary coping and very poor predictors of coping in specific situations.

[Survival after resection of lung metastasis from colorectal cancer]

OBJECTIVE

To analyze the results of resection of lung metastases from colorectal adenocarcinoma in selected patients, evaluating type of resection, morbidity and mortality associated with the procedure, and overall actuarial survival rates after surgery.

PATIENTS AND METHODS

Between 1988 and 1996, 811 patients were treated surgically for colorectal adenocarcinoma. Recurrent chronic lung metastases were resected, presumably with the intention to cure, in 15 patients in the series. One patient underwent surgery for pelvic recurrence and another seven for liver metastases, before resection of the lung metastases.

RESULTS

Twenty-seven wedge resections were performed, two being non-malignant and one patient requiring re-resection of new lung metastases. Unsuspected locations of lung metastasis were found in three patients during surgery. Perioperative mortality was zero. Mean follow-up was 50 months (range 28 to 99). Seven patients presented new occurrences of metastasis or tumor recurrence and died as a result. The actuarial survival rate was 48% at 5 years.

CONCLUSIONS

In selected patients, surgical resection of lung metastasis from colorectal cancer, with the assumed intention of cure, has yielded a good survival rate and zero perioperative mortality. It appears advisable to use an approach that permits exhaustive palpation of the pulmonary parenchyma, due to the risk of finding unsuspected metastases.

Laparoscopic ultrasound guidance for laparoscopic resection of benign gastric tumors

Laparoscopic excision of gastric leiomyoma is technically feasible and safe, but it may fail to localize the exact placement of the lesion because of the lack of tactile sensitivity. The authors present two cases of small gastric leiomyomas that were resected by a totally laparoscopic approach, assisted with intraoperative laparoscopic ultrasonography because the lesions could not be palpated. A gastric wedge resection with tumor-free margins was performed with an endostapler device. Use of a harmonic scalpel to divide the gastroepiploic vessels facilitated the laparoscopic procedure.

Incorporation of exogenous precursors into neutral lipids and phospholipids in rat hepatocytes: effect of ethanol in vitro

We studied the incorporation of different radioactively labeled exogenous substrates into the lipids of rat hepatocytes previously incubated with ethanol. Glycerol, oleate, and serine were all incorporated into neutral lipids to a significantly greater degree in the presence of ethanol, the increase in radioactivity in the triacylglycerol fraction being quite substantial. A similar ethanol-induced increase was found in the incorporation of these substrates into the various phospholipids. This lipogenic activity did not occur when the metabolism of ethanol was blocked by 4-methylpyrazole, an inhibitor of hepatic ADH (alcohol:NAD+ oxidoreductase, EC 1.1.1.1) activity, thus demonstrating that one of the initial effects of ethanol on lipid biosynthesis was mediated by some products of its metabolism in the liver. The only alteration that persisted in the presence of 4-methylpyrazole was an inhibitory effect on the esterification of free cholesterol from oleate, suggesting that ethanol specifically inhibits hepatic ACAT (acyl CoA:cholesterol O-acyltransferase, EC 2.3.1.26) activity.

How, when, and why bile duct injury occurs. A comparison between open and laparoscopic cholecystectomy

BACKGROUND

Bile duct injury (BDI) is a severe complication of laparoscopic cholecystectomy (LC). There is general agreement about the increase of this complication after LC vs open cholecystectomy (OC), but comparative studies are scarce. The aim of this paper has been to compare the incidence and clinical features of BDI after LC vs open procedures.

MATERIALS AND METHODS

3,051 OC, performed from June 1977 to December 1988 were retrospectively analyzed and compared with 1,630 LCs performed from June 91 to August 96, for which data were prospectively recorded. Age, sex, type of BDI, performance of intraoperative cholangiography (IOC), underlying biliary pathology, morbidity, mortality, and late morbidity were all analyzed.

RESULTS

BDI incidence was higher in group II (LC) (N: 16, 0.95%) than in group I, (OC, N: 19. 0.6%). BDI incidence was also higher in the group of patients in which it was necessary to convert to an open procedure (3/109, 2.7%, p < 0.05). BDIs were more frequently diagnosed intraoperatively in group I (OC, 18/19) than in group II (LC, 12/16). In both groups, BDI was more prevalent in cases operated by staff surgeons than residents, mainly in complicated gallbladder patients, with a bile duct of less than 7-mm diameter. Morbidity, postoperative stay, mortality, and late morbidity were similar after a BDI in both types of approach.

CONCLUSIONS

(1) BDI increases with LC. (2) BDI after LC carries a similar postoperative morbidity and mortality to those after OC. (3) Incidence of BDI in converted cases increases significantly and this constitutes a high-risk group.

Retroperitoneal liposarcomas. Study of 10 cases

INTRODUCTION

Retroperitoneal liposarcomas are unusual tumors. Their biological and clinical features different from other retroperitoneal sarcomas.

AIM

To analyze our series of retroperitoneal liposarcomas.

PATIENTS AND METHODS

Retrospective study of 10 patients with retroperitoneal liposarcoma diagnosed in the last 16 years at our institution. Symptoms, diagnosis, treatment and prognosis were analyzed.

RESULTS

Radical resection was done in all cases. Postoperative mortality was 10%. Complementary treatment was considered in each patient. Recurrent disease occurred in 8 patients (14 recurrences), during follow up. In 42% of them recurrences were resected. Actuarial 5-year survival rate was 44%.

CONCLUSION

Poor prognosis of retroperitoneal liposarcoma is due to its high recurrence rate.

[Aneurysm of the antero-inferior pancreatoduodenal artery as a cause of massive digestive hemorrhage]

We report a case of anterior inferior pancreaticoduodenal artery aneurysm fissured to the duodenum, which obliged to an emergency operation. This is an infrequent cause of upper gastrointestinal bleeding. Diagnosis, therapeutic options and prognosis of this pathology are discussed.

Responses of leptin to short-term fasting and refeeding in humans: a link with ketogenesis but not ketones themselves

We investigated the response of leptin to short-term fasting and refeeding in humans. A mild decline in subcutaneous adipocyte ob gene mRNA and a marked fall in serum leptin were observed after 36 and 60 h of fasting. The dynamics of the leptin decline and rise were further substantiated in a 6-day study consisting of a 36-h baseline period, followed by 36-h fast, and a subsequent refeeding with normal diet. Leptin began a steady decline from the baseline values after 12 h of fasting, reaching a nadir at 36 h. The subsequent restoration of normal food intake was associated with a prompt leptin rise and a return to baseline values 24 h later. When responses of leptin to fasting and refeeding were compared with that of glucose, insulin, fatty acids, and ketones, a reverse relationship between leptin and beta-OH-butyrate was found. Consequently, we tested whether the reciprocal responses represented a causal relationship between leptin and beta-OH-butyrate. Small amounts of infused glucose equal to the estimated contribution of gluconeogenesis, which was sufficient to prevent rise in ketogenesis, also prevented a fall in leptin. The infusion of beta-OH-butyrate to produce hyperketonemia of the same magnitude as after a 36-h fast had no effect on leptin. The study indicates that one of the adaptive physiological responses to fasting is a fall in serum leptin. Although the mediator that brings about this effect remains unknown, it appears to be neither insulin nor ketones.