Venâncio Avancini Ferreira Alves

Restaging of colorectal cancer based on the identification of lymph node micrometastases through immunoperoxidase staining of CEA and cytokeratins.

The present study was performed to identify tumor cells in lymph nodes from colorectal adenocarcinomas considered free of disease by the classic hematoxylin-eosin stain, based on the detection of the carcinoembryonic antigen (CEA) and cytokeratins in neoplastic epithelial cells. For this purpose, 603 lymph nodes from 46 lesions were stained by the peroxidase-antiperoxidase technique. Tumor cells were detected in 22 nodes from 12 patients, mainly in the subcapsular sinuses, permitting a restaging of these patients into two groups: those now considered to have metastatic disease and those free of metastases. However, the 5-year follow-up showed no statistical differences in survival between the two groups.

Effects of bariatric surgery on nonalcoholic fatty liver disease: Preliminary findings after 2 years

Background and Aim:  Although nonalcoholic fatty liver disease (NAFLD) is very common among morbidly obese patients, the effect of weight loss after bariatric surgery on inflammation and fibrosis related to NAFLD is still a matter of debate. The aim of this study was to evaluate the impact of Roux‐en‐Y gastric bypass (RYGB) surgery on NAFLD with a follow up of 2 years.

Combination of N‐acetylcysteine and metformin improves histological steatosis and fibrosis in patients with non‐alcoholic steatohepatitis

Aim:  There is no proven medical therapy for the treatment of non‐alcoholic steatohepatitis (NASH). Oxidative stress and insulin resistance are the mechanisms that seem to be mostly involved in its pathogenesis. The aim of our study was to evaluate the efficacy of N‐acetylcysteine (NAC) in combination with metformin (MTF) in improving the aminotransferases and histological parameters (steatosis, inflammation, hepatocellular ballooning, and fibrosis) after 12 months of treatment.

Liver mitochondrial dysfunction and oxidative stress in the pathogenesis of experimental nonalcoholic fatty liver disease

Oxidative stress and hepatic mitochondria play a role in the pathogenesis of nonalcoholic fatty liver disease. The aim of the present study was to evaluate the role of hepatic mitochondrial dysfunction and oxidative stress in the pathogenesis of the disease. Fatty liver was induced in Wistar rats with a choline-deficient diet (CD; N = 7) or a high-fat diet enriched with PUFAs-omega-3 (H; N = 7) for 4 weeks. The control group (N = 7) was fed a standard diet. Liver mitochondrial oxidation and phosphorylation were measured polarographically and oxidative stress was estimated on the basis of malondialdehyde and glutathione concentrations. Moderate macrovacuolar liver steatosis was observed in the CD group and mild liver steatosis was observed in the periportal area in the H group. There was an increase in the oxygen consumption rate by liver mitochondria in respiratory state 4 (S4) and a decrease in respiratory control rate (RCR) in the CD group (S4: 32.70 +/- 3.35; RCR: 2.55 +/- 0.15 ng atoms of O2 min-1 mg protein-1) when compared to the H and control groups (S4: 23.09 +/- 1.53, 17.04 +/- 2.03, RCR: 3.15 +/- 0.15, 3.68 +/- 0.15 ng atoms of O2 min-1 mg protein-1, respectively), P < 0.05. Hepatic lipoperoxide concentrations were significantly increased and the concentration of reduced glutathione was significantly reduced in the CD group. A choline-deficient diet causes moderate steatosis with disruption of liver mitochondrial function and increased oxidative stress. These data suggest that lipid peroxidation products can impair the flow of electrons along the respiratory chain, causing overreduction of respiratory chain components and enhanced mitochondrial reactive oxygen species. These findings are important in the pathogenesis of nonalcoholic fatty liver disease.

The prognostic value of CD147/EMMPRIN is associated with monocarboxylate transporter 1 co-expression in gastric cancer

The aim of the present work was to assess the role of monocarboxylate transporters (MCTs), namely MCT1 and MCT4 as well as MCT/CD147 co-expression in gastric tissues and evaluate their clinico-pathological significance in gastric carcinoma. For that, we analysed the immunohistochemical expression of MCT1, MCT4 and CD147, in a large series of gastric samples, including non-neoplastic, tumour and metastatic tissues. A significant decrease in MCT4 plasma membrane expression was observed from non-neoplastic to gastric primary malignant tissues and to lymph-node metastasis and both MCT1 and MCT4 correlated with CD147. Importantly, both MCT4 and CD147 were more frequently expressed in Laurens intestinal-type tumours and MCT1/CD147 co-expression was associated with advanced gastric carcinoma, Laurens intestinal type, TNM staging and lymph-node metastasis. Our results showed that the prognostic value of CD147 was associated with MCT1 co-expression in gastric cancer cells, supporting the view that CD147 plasma membrane activity is dependent on MCT co-expression.

Basaloid squamous carcinoma of oral cavity: a histologic and immunohistochemical study

Basaloid squamous carcinoma (BSC) is an aggressive variant of squamous cell carcinoma (SCC) with a predilection for the upper aerodigestive tract. In the English literature, approximately 40 cases of BSC have been described in the oral cavity. BSC has frequently been confused with adenoid cystic carcinoma (ACC), basal cell adenocarcinoma, and undifferentiated SCC. The purpose of the investigation was to examine the histological features and immunohistochemical expression of differentiation-related substances, including cytokeratin (CK) subtypes, vimentin, S-100, chromogranin, laminin, and type IV collagen, for the characterization of biological features of these tumours. We studied three cases of BSC of the oral cavity, three cases of ACC, and one case of basal cell adenocarcinoma. Well-differentiated and undifferentiated SCCs were also studied for comparison. The BSCs showed many histopathologic similarities to cases previously reported. Among the CK subtypes analyzed, CK14 was the only subtype expressed by all basaloid cells of BSC. Potentially useful for the differential diagnosis was the finding of CKs 7 and 19 expression in the basaloid cells of ACC, and CKs 7 and 8 in basal cell adenocarcinoma. In BSCs, laminin and type IV collagen were found in the microcystic spaces between basaloid cells, but neither ACCs nor basal cell adenocarcinoma showed this feature. These data suggest that immunohistochemical findings are helpful in distinguishing BSC of the oral cavity from other histopathologically similar tumours.

Association of polymorphisms of glutamate‐cystein ligase and microsomal triglyceride transfer protein genes in non‐alcoholic fatty liver disease

Background and Aims:  Although the metabolic risk factors for non‐alcoholic fatty liver disease (NAFLD) progression have been recognized, the role of genetic susceptibility remains a field to be explored. The aim of this study was to examine the frequency of two polymorphisms in Brazilian patients with biopsy‐proven simple steatosis or non‐alcoholic steatohepatitis (NASH): −493 G/T in the MTP gene, which codes the protein responsible for transferring triglycerides to nascent apolipoprotein B, and −129 C/T in the GCLC gene, which codes the catalytic subunit of glutamate‐cystein ligase in the formation of glutathione.

Spontaneous hepatitis B surface antigen clearance in a long-term follow-up study of patients with chronic type B hepatitis. Lack of correlation with hepatitis C and D virus superinfection

We investigated the frequency of HBsAg clearance and the possible role of viral superinfection in a long-term follow-up of 184 patients with chronic hepatitis B (CHB). Our subjects were 184 patients with chronic hepatitis B and the follow-up was 12–216 months (mean 66.2±53.7 months). The investigative methods used were: immunoenzymatic assays for HBV, HCV, HDV, and HIV markers; polymerase chain reaction (PCR) for HBV DNA; and liver biopsy and immunoperoxidase. During the follow-up, 20 of the 184 patients cleared serum HBsAg. A comparison of patients with persistent HBsAg (group I) and of those who cleared this marker (group II) showed a significant difference in mortality (P=0.002) between the two groups and a tendency to a more severe exacerbation (flare) in group II (P=0.07). Antibodies to hepatitis C and D virus as well as antibodies to HIV were equally distributed in both groups. Thirteen patients (7.9%) from group I, but none from group II, subsequently developed hepatocellular carcinoma. These results suggest that the frequency of spontaneous clearance of HBsAg during chronic HBV infection is low. No determinant factor for the clearance was found, including the presence of liver cirrhosis. Serum HBV DNA was undetectable by PCR after clearance in 16 out of 17 patients.

Human fatal yellow fever. Immunohistochemical detection of viral antigens in the liver, kidney and heart.

An immunohistochemical method to detect yellow fever antigen was developed using immune sera from rabbits and hamsters and hyperimmune ascitic fluid from mice. A search for the antigen was carried out in liver, kidney and heart in three fatal cases of yellow fever. In the liver it was present in the cytoplasm of hepatocytes, Councilman bodies and Kupffer cells. Yellow fever antigen was also detected in renal tubular epithelium and in groups of myocardial fibers. These findings suggest that viral replication occurs at sites other than the liver. Since yellow fever shares many features with other haemorrhagic fevers the use of immunohistochemistry can impart a significant improvement in the accuracy of its histopathological diagnosis.

Acromegaly: correlation between expression of somatostatin receptor subtypes and response to octreotide-lar treatment

About one-third of acromegalics are resistant to the clinically available somatostatin analogs (SA). The resistance is related to density reduction or different expression of somatostatin receptor subtypes (SSTR). This study analyzes SSTR’s expression in somatotrophinomas, comparing to SA response, hormonal levels, and tumor volume. We analyzed 39 somatotrophinomas; 49% were treated with SA. The most expressed SSTR was SSTR5, SSTR3, SSTR2, SSTR1, and SSTR4, respectively. SSTR1 and SSTR2 had higher expression in patients that had normalized GH and IGF-I. SSTR3 was more expressed in patients with tumor reduction. There was a positive correlation between the percentage of tumor reduction and SSTR1, SSTR2 and SSTR3 expression. Also, a positive correlation between SSTR2 mRNA expression and the immunohistochemical reactivity of SSTR2 was found. Our study confirmed the association between the SA response to GH and IGF-I and the SSTR2. Additionally, this finding was also demonstrated in relation to SSTR1.