The effect of consecutively larger doses of L-arginine on hepatic microcirculation and tissue oxygenation in hepatic steatosis.

BACKGROUND: Impairment of hepatic microcirculation in fatty liver is thought to render it more susceptible to the effects of ischaemia-reperfusion injury as compared to non-fatty liver grafts. The present study aimed to investigate the effect of consecutively larger doses of L-arginine on the hepatic microcirculation and tissue oxygenation of fatty liver. METHODS: Sprague-Dawley rats (200-250 g) were fed a liquid ethanol diet to induce hepatic steatosis or a normal diet for 6 weeks. Hepatic blood flow, microcirculation, tissue oxyhaemoglobin (HBO(2)) in response to consecutive intravenous bolus administrations of l-arginine (50 mg/kg, 100 mg/kg, 300 mg/kg and 500 mg/kg) or normal saline, were assessed. RESULTS: Baseline hepatic arterial flows and hepatic microcirculation values were significantly lower in steatotic livers vs. control livers. L-arginine significantly improved hepatic arterial, portal venous blood flow, hepatic microcirculation and tissue oxygenation in both fatty and control livers. CONCLUSIONS: The administration of NO in cumulatively larger doses is effective at improving hepatic blood flow, microcirculation and hepatic tissue oxygenation in steatotic liver and these results could form the basis of further work into using NO as a therapeutic tool to reclaim moderately steatotic grafts for use in liver transplantation.

Torsion of the gallbladder: a case report.

INTRODUCTION: Torsion of the gallbladder is a rare condition that most commonly affects the elderly. Pre-operative diagnosis is the exception rather than the rule. Any delay in treatment can be fatal as the gallbladder may rupture, leading to biliary peritonitis. CASE PRESENTATION: We present the case of an 80-year-old woman who was admitted with right upper quadrant pain initially thought to be secondary to acute cholecystitis. Subsequent ultrasound and computed tomography scans of the abdomen revealed signs suggestive of acute cholecystitis but neither modality detected any gallstones. As the patient's symptoms failed to resolve on conservative management, she was taken to theatre for an open cholecystectomy. Intra-operatively, the gallbladder had undergone complete torsion and appeared gangrenous. A routine cholecystectomy followed and she recovered from the operation without incident. CONCLUSION: It is rare to diagnose torsion of the gallbladder pre-operatively despite advances in diagnostic imaging. However, this differential diagnosis should be borne in mind particularly in the elderly patient, without proven gallstones, who fails to improve on conservative management. An emergency cholecystectomy is indicated in the event of diagnosing torsion of the gallbladder to avert the potentially lethal sequelae of biliary peritonitis.

Intussusception of the appendix secondary to endometriosis: a case report.

INTRODUCTION: Intussusception of the appendix is an extremely rare condition that ranges from partial invagination of the appendix to involvement of the entire colon. Endometriosis is an exceptionally rare cause of appendiceal intussusception and only very few cases have been reported in the literature to date. CASE PRESENTATION: A 40 year-old woman presented to clinic with a long history of lower abdominal pain, loose motions and painful, heavy periods. Subsequent colonoscopy revealed submucosal endometriotic nodules in the sigmoid as well as a polyp thought to be arising from the appendix, which had inverted itself. She was referred to a colorectal surgeon because the polyp could not be removed endoscopically despite several attempts. At laparotomy, the appendix had intussuscepted but it was possible to reduce it and therefore a simple appendicectomy was carried out. On histology, there were widespread endometrial deposits within the wall of the appendix and this was thought to be the basis for the intussusception. CONCLUSION: Histological evidence of the lead point is of crucial importance in cases of appendiceal intussusception, in order to exclude an underlying neoplastic process. Consequently, surgical resection is necessary either through an open or a laparoscopic approach. Gastrointestinal endometriosis should be considered as a cause of appendiceal intussusception in post-menarchal women with episodic symptoms and proven disease.

The role of nitric oxide in the modulation of hepatic microcirculation and tissue oxygenation in an experimental model of hepatic steatosis.

BACKGROUND: Impairment of hepatic microcirculation in fatty liver has been assumed to reduce tolerance of the liver against ischemia-reperfusion injury. The present study was aimed to investigate the role of nitric oxide (NO) in the regulation of hepatic microcirculation and tissue oxygenation in hepatic steatosis. METHODS: Sprague-Dawley rats (200-250 g) were fed a 2% cholesterol diet (n = 12) to induce hepatic steatosis or normal diet (n = 12) served as controls for 12 weeks. Hepatic blood flow, microcirculation, tissue oxyhemoglobin (HbO2) and cytochrome c oxidase radox status (Cyt Ox) in response to intravenous bolus administrations of l-arginine (300 mg/kg) or l-NAME (20 mg/kg) were assessed. RESULTS: Animals which developed moderate hepatic steatosis showed significant increase in tissue level of total lipids. Portal blood flow and hepatic microcirculation were significantly reduced as compared to controls (5.7 +/- 0.9 vs. 9.7 +/- 0.9 ml/min, P = 0.003 and 114.5 +/- 9.5 vs. 167.3 +/- 10.0 flux unit, P = 0.003). l-Arginine improved hepatic arterial and portal blood flows as well as microcirculation in fatty livers (P < 0.05), while l-NAME significantly worsened these parameters (P < 0.05). Hepatic tissue HbO2 and Cyt Ox were improved both in fatty and control livers following l-arginine, while l-NAME resulted in decreased HbO2 and Cyt Ox although a transit increase in tissue oxygenation was observed in fatty livers. CONCLUSIONS: NO is involved in the modulation of hepatic microcirculatory perfusion and oxygenation in cholesterol-induced hepatic steatosis. NO metabolisms may be regulated as a potential therapeutic strategy for impaired microcirculation in hepatic steatosis.

Impairment of hepatic microcirculation in fatty liver.

Fatty liver or hepatic steatosis, which is the result of the abnormal accumulation of triacylglycerol within the cytoplasm of hepatocytes, is a common histological finding in human liver biopsy specimens that is attributed to the effects of alcohol excess, obesity, diabetes, or drugs. There is a general consensus that fatty liver compromises hepatic microcirculation, the common exchange network upon which hepatic arterial and portal inflows converge, regardless of underlying etiology. A significant reduction in hepatic microcirculation has been observed in human fatty donor livers and in experimental models of hepatic steatosis. There is an inverse correlation between the degree of fat infiltration and both total hepatic blood flow and flow in microcirculation. Fatty accumulation in the cytoplasm of the hepatocytes is associated with an increase in the cell volume that reduces the size of the hepatic sinusoid space by 50% compared with a normal liver and may result in partial or complete obstruction of the hepatic sinusoid space. As a result of impaired hepatic microcirculation, the hepatocytes of the fatty liver have reduced tolerance against ischemia-reperfusion injury, which affects about 25% of the donors for liver transplantation because severe steatosis is associated with a high risk of primary nonfunction after liver transplantation.