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Biomedical subjects

A Manzin

Publications and source records attributed to A Manzin.

At least 55 records · Page 3Linked to original sources
PubMed1993

Trans-activation of epidermal growth factor receptor gene by the hepatitis B virus X-gene product.

The expression of the cellular gene coding for the epidermal growth factor (EGF) receptor (EGF-R) was assayed in the presence of hepatitis B virus (HBV) gene expression under different experimental conditions in human hepatoma-derived cells. First, transfection experiments of the well-differentiated HepG2 human hepatoma cell line using different expression vectors of the HBV X-region demonstrated that the X-gene product is capable of inducing EGF-R gene overexpression; in addition, by using a stable in vitro expression system for HBV, it was shown that EGF-R gene expression in these cells is greater than in the uninfected parent cells, and that this results in a three-fold increase in 125I-EGF binding. Finally, a CAT-expression assay was performed, indicating that regulatory regions of the EGF-R-gene are target sequences for X-protein trans-activation.

Carcinoma, Hepatocellular↗
PubMed1992

Lack of detectable human T-cell lymphotropic virus type I sequences in samples from multiple sclerosis patients.

Recently, inconclusive results have followed the early data on the possible association between multiple sclerosis (MS) and human T-cell lymphotropic virus type I (HTLV-I) infection. For this reason, we examined this hypothesis using the polymerase chain reaction (PCR) to study samples of differing origin from Italian MS patients. In particular, we developed a systematic analysis of paraffin-embedded brain white matter from histologically defined lesions of 14 MS patients using PCR and primer sets specific for HTLV-I sequences; additionally, cerebrospinal fluids (CSFs) from 12 patients and peripheral blood mononuclear cells (PBMCs) from subjects at the early and late phase of the disease were investigated for free HTLV-I virions and specific proviral sequences, respectively. In agreement with some groups who reported lack of HTLV-I sequences in PBMCs of MS patients but in clear contrast with others, we failed to detect specific viral sequences using this broad approach.

Base Sequence↗
PubMed1992

PCR analysis of HBV infected sera: relationship between expression of pre-S antigens and viral replication.

In order to determine the biological significance of the pre-S antigens in HBV infection, HBsAg sera were tested for the presence of pre-S1 and pre-S2. HBV DNA was detected by spot-hybridization and PCR. The data show a complete correlation between pre-S antigenemia and HBV DNA replication in anti-HBe positive cases. PCR but not spot-hybridization was adequately sensitive to also detect HBV DNA in roughly half of the preS negative sera as well. Thus PCR appears to be a valuable technique for detection of potentially infectious anti-HBe carriers.

DNA, Viral↗
PubMed1992

Human immunodeficiency virus type 1 and hepatitis B virus transcription in peripheral blood lymphocytes from co-infected subjects.

The molecular characteristics of peripheral blood lymphocyte (PBL) infection by hepatitis B virus (HBV) were studied in human immunodeficiency virus type 1 (HIV-1) infected subjects using highly sensitive polymerase chain reaction (PCR) based techniques. DNA and RNA samples were purified from PBLs of HIV-1 infected individuals, regardless of their HBV serological status and assayed using PCR and reverse-transcription (RT) PCR, respectively. The data shown here are an extension of previous reports documenting HBV and HIV-1 co-infection of PBLs and indicate that transcriptionally active HBV infection of PBLs is detectable in a significant proportion of asymptomatic HIV-1 infected patients.

DNA, Viral↗
PubMed1992

Sequence analysis of the hepatitis B virus pre-C region in hepatocellular carcinoma [HCC] and nontumoral liver tissues from HCC patients.

We investigated whether replication-competent pre-C/C defective mutants of hepatitis B virus (HBV) are detectable in primary human hepatocellular carcinoma (HCC) tissues from patients of a geographic area endemic for such mutants. DNAs extracted from formalin-fixed paraffin-embedded HCC samples were checked for the presence of specific HBV DNA sequences using the polymerase chain reaction (PCR). Amplified pre-C regions from nine HCC samples were directly sequenced as were samples of nontumoral liver tissues from five of these patients. The data show that hypervariable distal pre-C sequences were present in all nine HCC samples; this high variability was dependent on point mutations, which led to amino acid substitutions in nearly all cases. Interestingly, seven of the nine HBV DNA-positive samples from HCC tissues (but not samples from peritumoral liver tissue) showed mutations leading to amino acid substitution at the level of a distal cysteine residue. No mutation generating a translationally defective pre-C/C region was detectable in the tumor samples. Otherwise, in four of the six nontumoral liver tissues available from the same patients, a pre-C sequence with an in-frame TAG stop codon was detectable, although in three cases as a component of mixed population.

Amino Acid Sequence↗
PubMed1992

Absolute quantitation of viremia in human immunodeficiency virus infection by competitive reverse transcription and polymerase chain reaction.

A competitive polymerase chain reaction (PCR)-based assay for the quantitative detection of human immunodeficiency virus type 1 (HIV-1) viremia was developed and optimized. This method consists of the reverse transcription and subsequent amplification in the same tube of two similar RNA templates, the wild-type template to be quantified and a known amount of the internally deleted synthetic template, both with identical primer recognition sites. The same strategy also proved to be useful in the quantitative assay of HIV-1-specific cellular transcripts and proviral DNA sequences from peripheral blood mononuclear cells by using competitor DNA. The method might be of interest in the study of the precise level of HIV-1 activity during the different clinical phases of the infection and in the simple, fast, and methodologically correct molecular investigation of patients treated with specific antiviral compounds.

Base Sequence↗
PubMed1992

Molecular profile of human immunodeficiency virus type 1 infection in symptomless patients and in patients with AIDS.

Recent molecular evidence indicates that active human immunodeficiency virus type 1 (HIV-1) infection is detectable in both symptomless and symptomatic infected patients. For this main reason, it has been pointed out that precise quantitative analysis of viral activity in vivo is necessary, firstly, for the pathogenetic investigation of the steps relevant to infection progression and, secondly, for better clinical management of HIV-1-infected patients. In this study, the presence of HIV-1 genomic RNA in plasma samples, specific HIV-1 transcripts in peripheral blood mononuclear cells, and proviral DNA sequences were assayed for 33 HIV-1-infected patients (including symptomless and symptomatic subjects) by using a competitive polymerase chain reaction method that allows quantitation of the RNA/DNA target sequences. The quantitative results obtained confirm that transcription of HIV-1 structural genes and complete viral replication occur in all the HIV-1-infected patients independently of the clinical stage. However, although sharp individual differences were detected, a high degree of correlation of the molecular parameters studied with both disease progression and a decrease in the number of CD4+ T lymphocytes was documented. Interestingly, despite the increasing viremia level associated with infection progression, the mean transcriptional activity of individual infected cells was found to be only moderately greater in AIDS patients than in asymptomatic infected subjects. In addition, it was noted that quantitation of HIV-1 genomic RNA in plasma samples and quantitation of specific HIV-1 transcripts in peripheral blood mononuclear cells appear to be more reliable and sensitive markers of viral activity than quantitative analysis of proviral HIV-1 sequences in peripheral lymphocytes.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Umbilical blood flow and placental pathology.

The aim of the study was to establish whether or not placental morphostructural damage correlates with umbilical artery Doppler waveform and neonatal condition. To this end, seriated ultrasonographic monitoring, flowmeter tests on the cord artery and computerized cardiotocography were carried out in a population of 93 pregnant women in the second half of pregnancy. After birth placentas were subjected to macroscopic and microscopic examination. The Resistance Index showed a good correlation with placental vascular lesions, characterized by a distinct reduction in terminal villi and muscular wall arterioles. Two types of intrauterine growth retardation were discernible, the first of genetic origin with a low-profile growth curve and therefore not amenable to treatment, but with a positive fet l-neonatal prognosis, and the second with a pathologic placental component, presenting a late flattening growth curve with evolution towards fetal distress and a negative fetal-neonatal prognosis.

Female↗
PubMed1991

Detection of human immunodeficiency virus type 1 genomic RNA in plasma samples by reverse-transcription polymerase chain reaction.

An application of the polymerase chain reaction (PCR) to the direct detection of human immunodeficiency virus type 1 (HIV-1) viremia is described. The amplification of specific HIV-1 sequences of gag and env viral genes was carried out after the reverse-transcription of plasma samples (plasma RT-PCR) from seropositive subjects. The assay is faster and cheaper than detection of specific HIV-1 transcripts from peripheral blood mononuclear cells by RT-PCR. The data suggest that HIV-1 viremia is detectable by plasma RT-PCR in a large proportion of seropositive individuals.

Genes, env↗
PubMed1991

Levels of pre-S antigens and HBV DNA in sera from high and low viremic HBV carriers.

The biological and clinical significances of pre-S antigens and HBV replication were investigated. Some 125 sera, 28 from HBeAg and 97 from anti-HBe-positive HBsAg, carriers were studied. The aim was to verify whether pre-S antigens could be expressed in serum in complete absence of viremia. Pre-S proteins, determined by an enzyme immunoassay, were found in sera regardless of the presence of HBV DNA, as detected by spot-hybridization. The sera without detectable HBV DNA were investigated further by PCR using specific primers for the S and C regions of HBV. PCR analysis of samples revealed that 4 out of 5 HBeAg and 33 out of 41 (80.5%) anti-HBe positive sera contained HBV-amplified sequences of S and C regions. Pre-S antigen values correlated well with the amounts of HBV DNA in serum detected by PCR in anti-HBe-positive subjects with high titers of pre-S antigens (10(4)-10(6)). In addition, PCR highlighted the presence of HBV DNA sequences in 8 out of 17 (47.1%) pre-S-negative HBsAg-positive sera.

Antibodies, Monoclonal↗
PubMed1991

A single-step DNA extraction procedure for the detection of serum hepatitis B virus sequences by the polymerase chain reaction.

A rapid single-step procedure for the isolation of low molecular weight DNA using guanidinium thiocyanate and phenol as protein denaturants is described and applied for the detection of specific hepatitis B virus (HBV) DNA sequences from serum samples by the polymerase chain reaction (PCR). The novel technique is efficient and, when compared to the standard proteinase K/phenol/chloroform method has the advantage of being faster and easily adaptable to the routine processing of a high number of clinical samples by PCR and spot hybridization techniques.

Base Sequence↗
PubMed1991

Detection of human immunodeficiency virus type 1 transcripts in peripheral blood lymphocytes by the polymerase chain reaction.

A simplified application of the polymerase chain reaction (PCR) to the routine detection of human immunodeficiency virus type 1 (HIV-1) transcripts from peripheral lymphocytes of infected subjects is described. This technique is simpler than previously described assays and was shown to be highly sensitive after ethidium bromide staining of polyacrylamide gel electrophoresis of amplified material. The method can be used for the virologic evaluation of HIV-1-infected subjects, thus allowing early identification of seropositive patients with signs of active infection.

Cell Line↗
PubMed1990

Growth-factor independence of a new differentiated hepatitis B virus DNA-negative human hepatoma cell line.

The establishment of a new, differentiated, hepatitis B virus DNA-negative, human hepatoma cell line (named PLC/AN/2) is described. Neoplastic liver tissue was obtained during hepatectomy in an HBsAg-negative man. The established cell line is negative for alpha-fetoprotein and carcinoembryonic antigen; it has retained in vitro some of the differentiated functions of normal hepatocytes. Additionally, it presents a distinctive rearrangement (translocation) at the long arm of chromosome 4. The high degree of independence from serum growth factor requirements appears to be a major in vitro characteristic of PLC/AN/2 cells, making them a suitable model system for the more precise definition of the human hepatocellular carcinoma phenotype, including mechanisms of growth control.

Carcinoma, Hepatocellular↗
PubMed1990

[Salmonella in the province of Livorno. Epidemiological study over the last five years].

The authors refer on Salmonella species isolated from carriers, in USL 13 country, during the period of five years 1984-1988 in the microbiological laboratories of S.M.P. USL 13. N. 1240 Salmonella strains were isolated. N. 62 serotypes have been recognized of which about 77% were of the groups B, C1, E1. The trial shows a high positivity of more rare serotypes especially in summer period.

Carrier State↗
PubMed1989

Detection of hepatitis B virus DNA in serum using synthetic non-radioactive oligonucleotides.

A rapid and simplified technique for detecting hepatitis B virus (HBV) DNA by spot hybridisation in the sera of patients with different clinical forms of HBV infection was investigated using enzyme conjugated synthetic oligodeoxyribonucleotides as probes. These are able to hybridize to the S and C regions of the HBV L(-) DNA strand. When compared with a complete 32P-labelled HBV DNA probe, the synthetic oligonucleotides provided a sensitive and quick method for the routine survey of HBV infection. Moreover, the DNA extraction procedure used allowed the spot hybridisation technique to be applied and read easily and the results obtained within a few hours. It is concluded that synthetic cold probes can be used in hybridisation assays HBV DNA detection as part of current clinical laboratory procedures.

Carrier State↗
PubMed1987

Detection of HBV infectivity by spot hybridization in HBeAg-negative chronic carriers: HBV DNA in sera from asymptomatic and symptomatic subjects.

DNA of hepatitis B virus (HBV DNA) in sera from HBeAg-positive carriers is now the most important and reliable marker of infectivity, but its significance in the progression of chronic hepatitis in anti-HBe carrier status is still under discussion. In this study, viral DNA was tested by a simplified spot hybridization method in sera of 206 HBeAg-negative Italian subjects. In a group of 153 HBsAg carriers, we found that 15.6% of anti-HBe-positive and 10.5% of anti-HBe-negative samples contained viral DNA. No HBV DNA was revealed in 38 HBsAg-negative nor in 15 anti-HBs-positive subjects with different serological markers of HBV. Viral DNA in sera of HBeAg-negative patients with severe chronic liver disease was correlated with increased alaninetransferase activity and IgM anti-HBc. Thus the presence of HBV DNA in these sera not only predicts which subjects are potentially infectious but also indicates chronic progression of hepatitis. Finally, viral DNA extracted from Dane particles of nine anti-HBe-positive sera was characterized by the Southern blot technique. The hybridization pattern shows bands indicating the presence of replicative intermediates.

Alanine Transaminase↗