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Learning objects are elements that have been defined as reusable entities. However, their reusability is limited by the heterogeneity of the platforms that support them and by the standards employed in their development. A proposal of ours to deal with learning objects as Web services in order to solve the reusability problem has been presented in previous works. In addition to, the modification of learning management systems has also been proposed in order to support the integration and management of the Web services. In this context, this work describes what learning Web services are and presents a learning management systems analysis to show the characteristics that are important to facilitate the integration and management of the learning web services.

Hepatitis B virus (HBV) variants with precore mutation(s) resulting in the absence of HBeAg production have been associated with the occurrence of fulminant hepatitis in Japan, Israel, and southern Europe, where the prevalence of this HBV strain appears common. In areas such as United States, where HBV infection is not endemic, the role of this mutant virus in fulminant hepatitis is unknown. We developed an amplification refractory mutation detection system to detect specifically the presence of the G to A mutation at nucleotide position 1898, which is the most frequently observed mutation resulting in a precore stop codon. In addition, this method provided a quantitative measurement of the relative ratio of one strain to the other. Using this system, we tested HBV strains for the presence of the stop codon mutation in sera from 40 cases of fulminant hepatitis B occurring in the United States. Serum HBV DNAs from 28 patients were analyzed successfully. A mixture of wild-type and mutant strains in various ratios were observed in 15 patients, wild type exclusively in 11, and mutant exclusively in 2. Four of these patients had undergone liver transplantation for HBV-associated cirrhosis and developed fulminant HBV-associated hepatitis after transplantation. Pre- and posttransplant serum samples from one patient were analyzed: a mixture of wild-type and mutant HBV strains was detected in both samples. Our study demonstrated that both wild-type and mutant HBV strains are associated with fulminant hepatitis, and that in some patients in the United States, factors other than precore mutations contribute to the development of fulminant hepatitis.

The authors reviewed T2-weighted and T2*-weighted abdominal magnetic resonance (MR) images in 19 pathology-proved cases of hepatic iron overload to compare patterns of iron distribution among cirrhotic and precirrhotic patients with idiopathic hemochromatosis (IH), as well as nontransfusional hepatic siderosis of other causes. Fifteen patients had clinical and laboratory evidence of IH. Four patients without IH had cirrhosis with moderate siderosis. In the MR images of all 19 patients, the liver had low signal intensity. The pancreas of 10 of 11 cirrhotic patients with IH had low signal intensity. All four precirrhotic patients with IH and all four cirrhotic patients without IH had pancreas with normal signal intensity at MR. Thus, pancreatic signal intensity was decreased only in cirrhotic patients with IH in this limited series. Conversely, pancreatic signal intensity is often normal in precirrhotic patients with IH prior to the development of cirrhosis, a stage at which definitive diagnosis by means of quantitative liver biopsy is important because early phlebotomy may prevent morbidity and mortality from IH. In cirrhotic patients with MR evidence of increased hepatic iron, the cause of cirrhosis is less likely to be IH if pancreatic signal intensity is normal.

Interferon is currently the only approved medication in the United States for treatment of chronic hepatitis B and C infections. The mechanism of action of interferon and guidelines for its administration are reviewed. Important clinical studies involving its use in hepatitis B and C infections are discussed, and investigational therapies for chronic viral hepatitis are highlighted.

The clinicopathological features of 38 patients admitted consecutively for fulminant hepatic failure were studied. Histopathological material was reviewed in all patients. Both percutaneous and whole livers (either explanted or autopsy specimens) were available in 16 patients: whole livers only in 12 patients and biopsy specimens only in 10 patients. All patients were negative for antibodies to hepatitis C, whereas 24% had hepatitis B infection and 10% had adverse drug reactions. Livers from 75% of patients showed confluent hepatic necrosis. However, there was considerable variability in the extent of necrosis, and biopsy specimens from about 50% of the most severely affected livers showed only minimal bridging necrosis. In patients with massive hepatic necrosis, percutaneous liver biopsy specimens were frequently misleading because of regional inhomogeneities. Interestingly, five patients (13%) had established cirrhosis at the time of diagnosis. The best clinical predictors of survival were age and the maximal grade of encephalopathy. By contrast, neither the severity of confluent hepatic necrosis nor the etiology predicted the decision to transplant or the outcome. There were no differences in the histopathology corresponding to different etiologies. In summary, the approach to the patient with fulminant hepatic failure should be guided principally on clinical grounds, and further classification should be based on pathological and etiologic considerations. However, histological classification and prognosis based on percutaneous biopsy specimens alone may be misleading.

Our findings indicate that serum amino acid changes after OLT are complex and influenced by multiple factors including sepsis and use of parenteral hyperalimentation with exogenous amino acids. Additional factors which may influence the rate of normalization of amino acids after OLT include the presence of malnutrition (frequently observed before OLT) and the extent of pretransplant portal-systemic shunting. Our results demonstrate that the presence of septic complications and the use of CPN are important determinants of the postoperative levels of several amino acids, including the BCAA/AAA ratio. Our logistic regression model using the BCAA/AAA ratio predicted the occurrence of sepsis after OLT 77% of the time. Prospective assessment and validation of this model is under way.

Before the identification of the major mitochondrial antigens of primary biliary cirrhosis as components of the 2-oxo-acid dehydrogenase enzyme family, mitochondrial autoantigens were believed to be extremely heterogeneous and were divided into nine subtypes termed M1 to M9. This classification was based on the data derived from the relatively nonspecific biochemical and immunological techniques that were available. After the cloning and definition of the major autoantigens, more than 95% of the sera of patients with primary biliary cirrhosis were found to react with components of the 2-oxo-dehydrogenase enzymes; these enzymes correspond to the old M2 classification. Two other "M" species, dubbed M4 and M9, have attracted significant attention because they have been postulated to be prognostic indicators and more recently have been tentatively identified respectively as sulfite oxidase (EC 1.8.3.1) and glycogen phosphorylase (EC 2.4.1.1). Indeed, patients with the "overlap syndrome" are reported to have antibodies to M4 and a poor prognosis, whereas patients with antibodies to M9 have a favorable prognosis. To address the significance and definition of M4 and M9, we performed in-depth studies of sera from 11 patients with the overlap syndrome, 75 patients with primary biliary cirrhosis, 19 chronic active hepatitis patients, 13 patients with primary sclerosing cholangitis, 10 patients with cholangiocarcinoma, 20 patients with systemic lupus erythematosus, 20 patients with alcoholic cirrhosis, 17 patients with scleroderma and 30 normal individuals, using techniques of ELISA, complement fixation, immunoblotting and enzyme inhibition. We report herein that we were unable to show any disease-specific reactivity toward the proposed M4 and M9 antigens.(ABSTRACT TRUNCATED AT 250 WORDS)

Liver transplantation is now considered definitive therapy for end-stage liver disease and has been playing an increasingly important role in the management of fulminant hepatic failure. With the advent of effective immunosuppression and improved surgical techniques, high survival rates can be expected for most transplanted patients. It has become apparent, however, that transplantation for patients with viral hepatitis is associated with some unique problems because of the propensity for viral reinfection of the grafted liver. Patients with actively replicating hepatitis B viral infection pretransplantation appear to be most likely to experience clinically significant recurrent hepatitis. Recurrent hepatitis D (delta) and hepatitis C appear to be relatively less serious in the transplanted liver. Interventions to prevent or treat graft reinfection have thus far met with limited success. Further studies are needed to define more precisely which patients with viral hepatitis are likely to do poorly after liver transplantation, and to develop strategies for treating recurrent hepatitis in transplant recipients.

Many advances have been made in the understanding, diagnosis, and management of severe complications of liver disease. The pathogenesis of hepatic encephalopathy remains a challenge. Several toxins including ammonia, mercaptans, short-chain fatty acids, benzodiazepine-like substances, GABA-like substances, and impaired glutamatergic neurotransmission are at the top of the list of candidates. Use of the benzodiazepine antagonists is an experimental but promising new therapy in patients with hepatic encephalopathy. In patients with cirrhosis, spontaneous bacterial peritonitis (SBP) remains a common and highly lethal complication. The diagnosis of SBP is based on the polymorphonuclear cell count in the ascites and confirmed by culture of ascitic fluid. Early diagnosis and aggressive treatment has reduced mortality of SBP from greater than 90 per cent to 30 to 50 per cent. The appearance of cerebral edema in severe acute hepatocellular failure is associated with high mortality and conventional neurologic signs may be unreliable indicators of brain swelling. Current management of cerebral edema in fulminant hepatocellular failure may include early placement of an extradural sensor for continuous monitoring of intracranial pressure, so that short-term measures can be instituted making later liver transplantation safer. Coagulopathy remains a serious problem in patients with liver disease. Exchange plasmapheresis is a promising short-term adjuvant therapy. However, liver transplantation should be considered the definitive treatment for fulminant hepatocellular failure. The gastroenterologist often encounters multiorgan failure in patients with severe liver disease. Liver transplantation is now an important therapeutic consideration in almost every patient with severe, irreversible liver disease. Efforts should be targeted to early diagnosis of irreversible disease and coordination of patient care with a liver transplant center.

Chylous ascites is an uncommon clinical entity associated with lymphatic obstruction usually caused by underlying malignancy. The authors describe a patient with chylous ascites caused by constrictive pericarditis in the absence of mechanical lymphatic obstruction. Pathophysiological mechanisms for the development of chylous ascites in constrictive pericarditis include augmented lymph production and high impedance to lymph drainage caused by central venous hypertension. After pericardiectomy, the patient's ascites and edema resolved. Constrictive pericarditis should be considered a rare but potentially curable cause of chylous ascites.