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Biomedical subjects

J E Levi

Publications and source records attributed to J E Levi.

8 recordsLinked to original sources
PubMed2006

Headache features in patients with dengue virus infection.

The aim of this study was to describe the frequency and features of headache among patients with confirmed dengue virus infection and to compare the headache features in patients with dengue fever and dengue haemorrhagic fever, primary and secondary dengue infection, and patients with and without neurological involvement. Patients with classic dengue fever had a more intense headache than those with the more severe form of the disease, dengue haemorrhagic fever.

Adult↗
PubMed2002

A single window-period donation detected by human immunodeficiency virus p24 antigen after 5 years of routine screening in a group of Brazilian blood banks.

BACKGROUND AND OBJECTIVES: The purpose of this article was to describe the experience of screening for human immunodeficiency virus (HIV) p24 antigen (p24Ag) in blood donors, in four Brazilian Blood Banks, and to report the detection of the first window-period donation. MATERIALS AND METHODS: During 61 months (May 96 to June 01), 103 470 consecutive donations were screened for HIV p24Ag using commercially available enzyme-linked immunosorbent assay (ELISA) kits. Testing was carried out in accordance with the instructions supplied with the kits. RESULTS: Fifty-eight repeatedly reactive samples were identified [0.056% of the total; 95% confidence interval (95% CI): 0.042-0.070]. Ten of the 58 were confirmed as p24Ag positive after neutralization (0.010%; 95% CI: 0.004-0.016), nine of the 10 (0.009%; 95% CI: 0.003-0.014) were also HIV antibody positive and only one (0.001%; 95% CI: 0-0.003) was HIV antibody negative. CONCLUSIONS: In this setting the rate of sole p24Ag-positive donations was one in 103 740. This figure corresponds closely with the previously estimated yield of one in 87 796 donations. The yield of HIV p24Ag+ : Ab- has been previously estimated in our centres to be 1 : 87 796 donations, a value similar to that observed in actual practice.

Blood Banks↗
PubMed1998

Human papillomavirus DNA and p53 status in penile carcinomas.

Our study aimed at evaluating the presence of human papillomavirus (HPV) DNA in a series of 84 paraffin-embedded (PET) penile carcinomas. We have also investigated the presence of p53 mutations in these tumors by immunohistochemistry (IHC), single-stranded conformational polymorphism (SSCP) and DNA sequencing. Tissues were submitted to amplification of a 268 bp fragment from the beta-globin gene and a fragment of the E6 gene of HPV types 6, 11, 16 and 18. Twenty samples (18 fixed in Bouin's solution and 2 in buffered formalin) were found inadequate and were excluded from the analysis. In the remaining 64 tumors, HPV DNA was found in 26% of the samples. The prevalence of HPV in fresh samples of the same tumors was 56%. The most prevalent type was HPV 16 in both fresh samples and PET. Isotopic in situ hybridization was performed in all PET samples, but only 2 cases were positive, 1 for HPV 16 and 1 for HPV 18. Immunohistochemistry with anti-p53 pAb 1801 antibody showed a positive nuclear reaction over more than 5% of tumor cells in 26% of the cases. SSCP of exons 5-8 of the p53 gene was performed on 9 HPV-positive and 12 HPV-negative specimens. Abnormal mobility was found in 26% of the tumors, of which 2 were HPV-positive and 5 HPV-negative. Point mutations were detected in p53 exons 6 (1 case), 7 (1 case) and 8 (5 cases), showing that high-risk type HPVs and mutated p53 may coexist in these tumors. Our data indicate that a subset of penile carcinomas are etiologically related to HPV and that an overlapping subset may arise from mutational events in the p53 gene.

Adult↗
PubMed1992

A monoclonal antibody (IID510g52) for the determination of functional domains within integrin cell surface receptors.

Monoclonal antibodies against cell surface receptors can be useful for the study of structural and biochemical features involved in protein interactions underlying platelet adhesion and aggregation. We report here the characterization of a monoclonal antibody, IID510g52 (hereafter referred to as IID5), which has been selected based on its specific binding properties against the platelet membrane glycoprotein IIIa. Characterization of the reactive epitope, including evolutionary conservation and identification of related IID5 target antigens in tumor cells, suggest that the IID5 epitope is implicated in the ligand-binding function of integrin receptors. Indeed, we show that this MoAb acts as a potent inhibitor of platelet aggregation and cell adhesion. Taken together, these results indicate that such a monoclonal may be a strategic tool for better understanding multiple integrin-mediated adhesive reactions, as well as the determination of interacting recognition sites.

Adult↗
PubMed1989

Human papillomavirus DNA in respiratory papillomatosis detected by in situ hybridization and the polymerase chain reaction.

The authors have demonstrated the presence of human papillomavirus (HPV) types 6 and 11 in 10 of 13 (77%) juvenile laryngeal papillomatosis by in situ DNA hybridization using as probes the radiolabeled DNAs of HPVs 6, 11, 16, and 18. Of six specimens from adult laryngeal papillomatosis assayed by the same technique, only 33% were positive. Immunohistochemistry to detect HPV capsid antigens performed on serial sections gave positive signals in 44% (8 of 18) of the specimens, all from juvenile lesions. These results were in agreement with in situ hybridization, except in two cases. When both series (juvenile and adult) were analysed by amplification of a 450-bp fragment corresponding to the L1 ORF of the HPV genomes directed by the polymerase chain reaction, the frequency of positive specimens rose to 100%. Our data agree with the concept that HPV is implicated in the etiology of laryngeal papillomatosis.

Adolescent↗
PubMed1988

Morphologic evidence that disruption of the Golgi apparatus in PFHR 9-tumor cells causes disturbance in the traffic through this organelle.

PFHR 9 is a murine teratocarcinoma-derived tumor which produces basement membrane components. Electron microscopy of the tumor cells disclosed a disorganization of the Golgi complex whose saccules, instead of being flattened, round up into 0.13 micron-wide spherical vesicles (SV). Their shape does not permit the normal stacking of parallel cisternae, and thus these SV become intermingled with transport vesicles (TV) which measure 44 nm in diameter. The cytoplasm of these tumor cells contains numerous multivesicular bodies (MVB) of varying size (ranging from 0.3 to 2.6 micron), which occupy 7% of the cellular volume. These MBV are packed with very many small vesicles similar in all aspects to the TV, and also contain a few larger vesicles which resemble the altered Golgi saccules (SV). Since these MVB display morphologic evidence for gradual lysis of their contents and strongly react with the cytochemical method for acid phosphatase, it is assumed that MVB are autophagic vacuoles which result from the accumulation of TV. This seems to be a unique example of a disease of the Golgi stack, with consequent accumulation and disposal of this material via autophagic vacuoles.

Animals↗
PubMedDate not supplied

Hepatitis G virus/GB virus C in Brazil. Preliminary report.

Hepatitis G virus/GB virus C is a novel flavivirus recently detected in hepatitis non A-E cases. In this study, the presence of this virus in chronic non-B, non-C hepatitis patients was evaluated using GBV-C specific PCR and this virus was detected in one out of thirteen patients. This patient has presented a severe liver failure, has lived for a long time in the Western Amazon basin and no other cause for this clinical picture was reported. The impact of the discovery of this new agent is still under evaluation throughout the world. The study of the prevalence of this virus among chronic hepatitis patients and healthy individuals (as blood donors) will furnish subside to evaluate its real pathogenicity.

Adult↗