Trends and projections of hepatitis C virus epidemiology in Latin America.

BACKGROUND AND AIM: The purpose of the present investigation is to provide an analysis of previous works on the epidemiology of the hepatitis C virus (HCV) infection from six countries throughout Latin America, to forecast the future HCV prevalence trends in Argentina, Brazil, Mexico and Puerto Rico, and to outline deficiencies in available data, highlighting the need for further research. METHODS: Data references were identified through indexed journals and non-indexed sources. Overall, 1080 articles were reviewed and 150 were selected based on their relevance to this work. When multiple data sources were available for a key assumption, a systematic process using multi-objective decision analysis (MODA) was used to select the most appropriate sources. When data were missing, analogues were used. Data from other countries with similar risk factors and/or population compositions were used as a proxy to help predict the future trends in prevalence. RESULTS: The review indicates that the dominant genotype is type 1. HCV prevalence in the analysed countries ranges from 1 to 2.3%. The Latin American countries have been very proactive in screening their blood supplies, thus minimizing the risk of transmission through transfusion. This suggests that other risk factors are set to play a major role in continued new infections. The number of diagnosed and treated patients is low, thereby increasing the burden of complications such as liver cirrhosis or hepatocellular carcinoma. The HCV prevalence, according to our modelling is steady or increasing and the number of infected individuals will increase. CONCLUSIONS: The results herein reported should provide a foundation for informed planning efforts to tackle hepatitis.

Liver transplantation for neuroendocrine tumors: progress and uncertainty.

Metastases from neuroendocrine tumors (NET) of the gastrointestinal tract, carcinoids, and endocrine pancreatic tumors (EPT) can be limited to the liver for long periods and may have slow growth. The symptoms are often related to hormone overproduction, and debulking surgery-for example, liver resection-is recommended to achieve tumor remission or symptom palliation. If liver resection is not feasible, hepatectomy and orthotopic liver transplantation (OLT) have been proposed. For EPT where the primary tumor is located in the head of the pancreas it may be advantageous to resect the primary tumor and the liver metastases en bloc and perform a multivisceral transplantation (MVTx).

Hepatic gene expression in histologically progressive nonalcoholic steatohepatitis.

Although the molecular basis for the pathophysiology of nonalcoholic steatohepatitis (NASH) is poorly understood, insulin resistance and mitochondrial dysfunction are physiologic hallmarks of this condition. We sought evidence of a transcriptional or pretranscriptional basis for insulin resistance and mitochondrial dysfunction through measurement of hepatic gene expression (messenger RNA [mRNA]) using high-density synthetic oligonucleotide microarray analysis (Hu6800 GeneChip, Affymetrix, CA). Global hepatic gene expression was determined in snap-frozen liver biopsy specimens from 4 groups: (1) patients with cirrhotic-stage NASH (n = 6), (2) patients with cirrhosis caused by hepatitis C virus (HCV) (n = 6), (3) patients with cirrhosis secondary to primary biliary cirrhosis (PBC) (n = 6), and (4) healthy controls (n = 6). Genes were considered to be expressed differentially in NASH only if there was a greater than 2-fold difference in abundance of mRNA when compared with each of the control groups. Sixteen genes were uniquely differentially expressed (4 overexpressed and 12 underexpressed) in patients with cirrhotic-stage NASH. Genes that were significantly underexpressed included genes important for maintaining mitochondrial function (copper/zinc superoxide dismutase, aldehyde oxidase, and catalase). Glucose 6-phospatase, alcohol dehydrogenase, elongation factor-TU, methylglutaryl coenzyme A (CoA), acyl CoA synthetase, oxoacyl CoA thiolase, and ubiquitin also were underexpressed in NASH. Genes that were overexpressed in NASH included complement component C3 and hepatocyte-derived fibrinogen-related protein, potentially contributing to impaired insulin sensitivity. In conclusion, these studies provide evidence for a transcriptional or pretranscriptional basis for impaired mitochondrial function (attenuated capacity for the dismutation of reactive oxygen species) and diminished insulin sensitivity (increased acute phase reactants) in patients with histologically progressive NASH. Further studies are required to determine the mechanism and the physiologic significance of these findings.

Transjugular intrahepatic portosystemic shunts: an update.

Transjugular intrahepatic portosystemic shunts (TIPS) have been used in the treatment of complications of portal hypertension. TIPS is used for the control of acute variceal bleeding and for the prevention of vericeal rebleeding when pharmacologic therapy and endoscopic therapy have failed. Patients with refractory ascites with adequate hepatic reserve and renal function who fail to respond to large volume paracentesis may be reasonable candidates for TIPS. Promising indications for TIPS are Budd-Chiari syndrome uncontrolled by medical therapy, severe portal hypertensive gastropathy, refractory hepatic hydrothorax, and hepatorenal syndrome. TIPS cannot be recommended for preoperative portal decompression solely to facilitate liver transplantation. Special care should be taken to insure proper placement of the stent to avoid increasing the technical difficulty of the transplantation procedure. The major limiting factors for TIPS success are shunt dysfunction and hepatic encephalopathy. Because shunt stenosis is the most important cause of recurrent complications of portal hypertension, a surveillance program to monitor shunt patency is mandatory. The MELD score may be useful in predicting post-TIPS survival, and also in counseling patients and their families.

Accuracy of computer diagnosis of melanoma: a quantitative meta-analysis.

BACKGROUND: Recent developments in computer technology have raised expectations that fully automated diagnostic instruments will become available to diagnose cutaneous melanoma without the need of human expertise. OBJECTIVES: To critically review the contemporary literature on computer diagnosis of melanoma, evaluate the accuracy of such computer diagnosis, analyze the influence of study characteristics, and compare the accuracy of computer diagnosis of melanoma with human diagnosis. METHODS: Quantitative meta-analysis of published reports. DATA SOURCES: Eligible studies were identified by a MEDLINE search covering the period from January 1991 to March 2002, by manual searches of the reference lists of retrieved articles, and by direct communication with experts. RESULTS: Thirty studies with substantial differences in methodological quality were deemed eligible for meta-analysis. Five of these complied with the predetermined list of "good quality" requirements, but none met all methodological quality requirements. Ten of these studies compared the performance of computer diagnosis with human diagnosis. The diagnostic accuracy achieved with computer diagnosis was statistically not different from that of human diagnosis (log odds ratios, 3.36 vs 3.51; P =.80). The diagnostic performance of the computer diagnosis was better for studies that used dermoscopic images than for studies that used clinical images (log odds ratios, 4.2 vs 3.4; P =.08). Other study characteristics did not significantly influence the accuracy of the computer diagnosis. CONCLUSIONS: The computer diagnosis of melanoma is accurate under experimental conditions, but the practical value of automated diagnostic instruments under real-world conditions is currently unknown. We suggest minimum requirements for methodological quality in future experimental studies or, ideally, randomized controlled trials.