Molecular epidemiology of hepatitis B virus in Afro-Venezuelan populations

Summary.  Hepatitis B virus (HBV) infection among Venezuelan populations of African origin was analyzed. These populations exhibited lower HBV prevalence than the one found in the African continent. Sequence analysis of 6 isolates showed that 3 belonged to genotype F, while the 3 others were HBV genotype A. HBV genotype A was more common in the Afro-Venezuelan groups than in the general Venezuelan population. This might reflect the introduction of genotype A during the slavery period. The absence of the African genotype E among these isolates supports the hypothesis of a recent origin for this HBV genotype. HBV genotype F has already been introduced to these relatively isolated communities. Received February 18, 2002; accepted March 8, 2002 Published online July 22, 2002     

Oral hairy leukoplakia. Histopathologic and cytopathologic features of a subclinical phase

Accurate diagnosis of oral hairy leukoplakia (OHL) is important because it may be an early indicator of undiagnosed HIV infection; moreover, it may be a prognostic indicator. Our purpose was to investigate the histopathologic features of subclinical OHL and to evaluate and support the rationale of detecting subclinical OHL with cytopathology. The Epstein-Barr virus (EBV) was detected by immunohistochemistry and in situ hybridization in 4 cases of macroscopically normal lateral borders of tongue mucosa from 8 AIDS necropsies and in none of 8 controls. The histopathologic features were specific when based on nuclear changes: Cowdry type A inclusion, ground glass, and nuclear beading. Smears were obtained from 50 patients with AIDS, without OHL, from the scraping of lateral borders of the tongue. Numerous clusters of the cells were associated with Candida organisms (30% of cases). Nuclear changes were observed in 12 patients (24%) on both sides of the tongue. We describe the histopathologic features of subclinical OHL, and our observations suggest that cytopathology can detect OHL in the subclinical phase.     

Indirect enzyme‐linked Immunosorbent assay for detection of cow's milk in goat's milk

An indirect enzyme‐linked immunosorbent assay (ELISA) has been developed for the specific detection of cow's milk (1–25%) in goat's milk. The test uses polyclonal antibodies raised in rabbits against bovine whey proteins (BWP). The anti‐BWP antibodies were recovered from the crude antiserum by immunoadsorption and elution from a column containing immobilized BWP. The anti‐BWP antibodies were biotinylated and rendered cow's milk specific by mixing them with lyophilized ovine and caprine whey proteins. Streptavidin‐peroxidase was used to detect the biotinylated anti‐BWP antibodies bound to bovine milk proteins immobilized on 96‐well plates. The colour developed by the subsequent enzymic conversion of the substrate gave clear absorbance differences when assaying mixtures of goat's milk containing variable amounts of cow's milk.     

APO-1(CD95)-dependent and -independent antigen receptor-induced apoptosis in human T and B cell lines

Certain B and T cell lines respond to activation signals, e.g.through the antigen receptor, by undergoing apoptotlc cell death.In T cells it has been recently shown that TCR-mediated apoptosisinvolves APO-1/Fas (CD95) receptor-ligand interaction. To investigatewhether the TCR-CD3 complex can trigger alternative apoptosispathways we generated subclones of the T cell line Jurkat whichwere completely resistant towards APO-1-mediated apoptosis.These Jurkat^R cells differed phenotypically from sensitive parentalJurkat^S cells only by the lack of APO-1 protein expression.Although Jurkat^R cells responded normally to anti-CD3 stimulationby expression of APO-1 ligand they failed to undergo anti-CD3-inducedapoptosis. Thus, in Jurkat cells APO-1 -mediated apoptosis wasthe main, and might be the only, mechanism for anti-CD3-inducedcell death. However, BL-60 B cells, highly sensitive to anti-IgM-inducedapoptosis, did not use the APO-1 receptor-ligand system becausethey failed to express APO-1 ligand mRNA. Taken together, ourresults suggest that malignant T and B cell lines may use APO-1receptor-ligand-dependent and -independent antigen receptor-inducedapoptosis pathways respectively. Similarly, differential pathwaysmay be used by T and B cell subsets.     

A computer model for the study of breast cancer

A computer model was designed as a relational database to assess breast cancer screening in a cohort of women where the growth and development of breast cancer originates with the first malignant cell. The concepts of thresholds for growth, axillary spread, and distant sites are integrated. With tumor diagnosis, staging was performed that includes clinical and sub-clinical states. The model was parameterized to have staging characteristics similar to data published by the Surveillance, Epidemiology, and End-Results (SEER) Program. Validation was accomplished by comparing simulated staging results with non-SEER sources, and simulated survival with independent clinical survival data.     

Cytokine flow cytometry differentiates the clinical status of multiple sclerosis (MS) patients

In this study we have examined intracellular cytokines in peripheral blood mononuclear cells (PBMC) of MS patients by flow cytometry (cytokine flow cytometry). MS progressive patients showed an increased number of cells producing interferon-gamma (IFN-gamma) after activation with phorbol 12-myristate 13-acetate and ionomycin, compared with patients with clinically inactive forms (P < 0001) and with healthy controls (P = 0001). These cells belonged to the CD4+ and CD8+ subsets in similar proportions. Clinically inactive patients showed a lower level of cells producing IL-2 than controls (P = 0.03) and active MS patients (P = 0.03). Most IL-2-producing cells were CD4+ lymphocytes, although a small part of the IL-2 was also produced by CD8+ cells. The percentage of cells producing simultaneously IL-2 and IFN-gamma was increased in active MS and they were mainly CD4+ lymphocytes. No differences in the production of IL-4 were observed between groups. However, we found an increased IL-10 production in clinically active MS patients (P = 0.03). Treatment with IFN-beta of active MS patients showed lower levels of cytokines when compared with untreated MS patients. This methodological approach could help in the follow up and therapeutic monitoring of MS patients.     

Prevalence of human T-cell lymphotropic virus type 1 (HTLV-1) and HTLV-2 infection among Spanish drug users measured by HTLV-1 assay and HTLV-1 and -2 assay. HTLV-1 and HTLV-2 Spanish Study Group.

The prevalence of human T-cell lymphotropic virus type 1 (HTLV-1) and HTLV-2 infection in 1992 and 1993 was determined by testing 2,152 specimens from injection drug users living in 11 geographic areas in Spain. Results obtained by an authentic HTLV-1 and -2 test were compared with those obtained by an HTLV-1 assay. HTLV infection was identified in 7 of 11 regions, with an overall prevalence of 2.5% (range, 0.4 to 11.5%). Fourty-four (81%) of 54 subjects were infected with HTLV-2; the viral strains in the remaining 10 subjects could not be serologically typed. Underestimation of HTLV infection because of the low sensitivities of HTLV-1 enzyme immunoassays for HTLV-2 antibody was relatively low (< 20%). Therefore, previous epidemiologic findings generated with HTLV-1 enzyme immunoassays appear to be reasonably accurate. Our results suggest that the rate of HTLV infection may have been increasing recently among Spanish drug users.     

Inhibin alpha-subunit (INHA) gene and locus changes in paediatric adrenocortical tumours from TP53 R337H mutation heterozygote carriers

The R337H TP53 mutation is a low-penetrance molecular defect that predisposes to adrenocortical tumour (ACT) formation in Brazilian and possibly other populations. Additional genetic defects may be responsible for the variable expression of ACTs in these cases. The inhibin α-subunit gene (INHA) on 2q33-qter has been implicated in mouse adrenocortical tumourigenesis. We studied 46 pediatric patients with ACTs from Brazil for INHA genetic alterations; 39 of these patients were heterozygous carriers of the R337H TP53 mutation. We first mapped the INHA gene by radiation hybrid analysis and determined 10 linked microsatellite markers in an area flanked by D2S1371 and D2S206 on 2q33-qter. These markers were then used for loss of heterozygozity (LOH) studies in nine paired germline and tumour DNA samples. Mapping placed the INHA gene in close proximity to D2S2848 (SHGC11864) with a log of odds (LOD) score of 5.84. LOH for at least one marker in the region was identified in 8/9 tumours (89%). Six patients were heterozygous for three INHA mutations: one in exon 1, 127C>G, and two in exon 2, 3998G>A and 4088G>A, all leading to amino acid substitutions (P43A, G227R, and A257T, respectively). A257T is located in a conserved INHA region, highly homologous to transforming growth factor-ß; both G227R and A257T change polarity, and, in addition, G227R changes the pH. We conclude that these sequence alterations and the detected 2q allelic changes suggest that INHA may be one of the contributing factors needed for ACT formation in pediatric patient carriers of the R337H TP53 mutation.     

Immunoglobulins and other serological parameters in Chagas'' disease: evidence for increased IgA levels in the chronic digestive form.

Immunoglobulin levels were measured in serum samples from 36 patients with different clinical forms of chronic Chagas' disease. Increased IgA levels were observed in 50% of the patients in the chronic digestive group and there was a significant correlation with the severity of the disease. IgG and IgM levels were within the normal range. Anti-ssDNA antibodies and EVI (endothelium, vessels and interstitium) antibodies were found in some patients with different clinical forms of the disease.