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Biomedical subjects

M Mariotti

Publications and source records attributed to M Mariotti.

At least 55 records · Page 3Linked to original sources
PubMed1996

Interleukin 1 induces an autocrine loop hepatocyte growth factor/c-Met in murine Kaposi-like spindle cells.

Several cytokines, growth factors and the HIV transactivator Tat were shown to be involved in the pathogenesis of Kaposi's sarcoma. BKV/tat transgenic mice develop Kaposi's sarcoma-like lesions, and spindle-shaped cells (TTB) have been derived from these lesions. Here we show that TTB cells co-express hepatocyte growth factor (HGF) and its receptor, the product of the oncogene c-Met. An autocrine loop HGF/Met sustains spindle cell proliferation in vitro; indeed, an antisense oligomer targeted against HGF markedly inhibited cell growth. Moreover, HGF and Met are overexpressed after exposing TTB cells to the proinflammatory cytokine interleukin 1 (IL-1). We argue that upon exposure to IL-1, an HGF/Met autocrine loop is induced which could explain the appearance of multiple foci of uncontrolled growth. In addition, due to its angiogenic activity, HGF may also sustain the neovascularization typical of Kaposi's sarcoma lesions.

Animals↗
PubMed1996

Over-expression of hepatocyte growth factor in human Kaposi's sarcoma.

Kaposi's sarcoma is a highly vascularized multifocal tumor which frequently appears as a complication of HIV infection. It has been suggested that a disorder in the cytokine network may contribute to the development of the disease. We examined the expression of several cytokines in human sporadic Kaposi's-sarcoma specimens, as well as in spindle cells cultured from human lesions, and consistently found high levels of expression of hepatocyte growth factor (HGF). In addition, human lesion-derived spindle cells synthesize and secrete biologically active hepatocyte growth factor and express the hepatocyte-growth-factor receptor (c-MET). Moreover, elevated levels of transforming growth factor beta 1 (TGF beta 1) mRNA were found in lesions of human sporadic Kaposi's sarcoma and in lesion-derived spindle cells which also over-express urokinase. Since HGF, TGF beta 1 and urokinase are all involved in capillary-vessel organization, dysregulation of these interacting agents may play a role in the initiation and/or progression of Kaposi's sarcoma, stimulating the growth of spindle cells and recruiting endothelial cells into the lesion.

Base Sequence↗
PubMed1996

Infection by hepatitis C virus through contaminated intravenous immune globulin: results of a prospective national inquiry in France.

BACKGROUND: A recent hepatitis C virus (HCV) outbreak has been suspected of being caused by an infusion of intravenous immune globulin. STUDY DESIGN AND METHODS: Three laboratories were mandated by the French regulatory agency to prospectively screen on a national scale those persons having received suspected batches: 233 exposed patients were recalled and tested for HCV antibody and for HCV RNA. RESULTS: Nineteen patients (8.1%) were found positive for HCV RNA; 7 of these 19 were positive for the HCV antibody. CONCLUSION: The link between HCV infection and intravenous immune globulin was reinforced by the overrepresentation of the 2b genotype (58%), which contrasts with the low prevalence of this genotype in France (1%).

Adult↗
PubMed1996

Detection of human herpesvirus 8 DNA sequences before the appearance of Kaposi's sarcoma in human immunodeficiency virus (HIV)-positive subjects with a known date of HIV seroconversion.

The presence of human herpesvirus 8 (HHV-8) DNA sequences was sought by polymerase chain reaction (PCR) in peripheral blood mononuclear cells of 4 groups: 6 human immunodeficiency virus (HIV)-infected persons with well-defined dates of seroconversion, during the period between the diagnosis of HIV infection and the appearance of Kaposi's sarcoma (KS); 45 HIV-positive persons with no symptoms of HIV infection; 11 AIDS patients with KS; and 14 AIDS patients without KS. HHV-8 DNA PCR was positive in 3 of the 6 patients during HIV infection preceding the appearance of KS and in all but 1 of 11 AIDS patients with KS. HHV-8 DNA PCR was negative in all but 1 of the 45 HIV-positive persons with no symptoms of infection and in all but 1 AIDS patient without KS. These results indicate that HHV-8 DNA may be detected several years before the occurrence of KS in HIV-infected subjects.

Adult↗
PubMed1995

Correlation between viral DNA load and serum anti p19 antibody concentration in symptomless human T-lymphotropic virus type-I (HTLV-I)-infected individuals.

In order to determine whether serum anti-human T-cell lymphotropic virus type I (HTLV-I) antibody concentration is correlated with cellular viral DNA load, these 2 biological parameters were established in 22 symptomless HTLV-I carriers. The proviral copy (PVC) number was determined through quantificative polymerase chain reaction. Specific antibody titers were determined by Western blot with the end-point dilution method; the quantification of each antibody was performed through ScanBlot by determination of the peak height of each Western-blot band. A positive correlation was observed between the PVC number and the titer of total antibodies. When the association between the peak height of each antibody and the PVC number was studied, a significant positive correlation was observed only with anti-p 19. Further evaluation through follow-up studies of symptomless HTLV-I individuals is needed to clarify the value of anti-HTLV-I antibody titer as a predictor of disease progression.

Adult↗
PubMed1995

Comparative study of conventional and novel strategies for the detection of hepatitis C virus RNA in serum: amplicor, branched-DNA, NASBA and in-house PCR.

The aim of this study was to compare the sensitivity and specificity of conventional procedures (in-house one-stage polymerase chain reaction (PCR) and in-house nested PCR) and of new technologies (rTth DNA polymerase (Amplicor), branched-DNA, NASBA (nucleic acid amplification system)) for the qualitative detection of hepatitis C virus (HCV) RNA in serum of HCV-infected individuals. Serum samples from 37 anti-HCV-positive individuals (15 with a normal alanine aminotransferase (ALT) level, 22 with an elevated ALT level) and 10 anti-HCV-negative individuals as negative controls were studied. A second panel, including 9 diluted serum samples (from 1/10 to 1/100,000) was constituted to establish the differences of sensitivity of the 5 procedures with small quantities of HCV RNA in the serum. The anti-HCV-positive individuals with elevated ALT gave positive results with all 5 procedures. In patients with a normal ALT level, the assays with the highest sensitivity were Amplicor, NASBA and nested RT-PCR, followed by one-stage RT-PCR, then branched-DNA. One false-positive result was observed with Amplicor, and two with in-house nested PCR. On diluted samples, Amplicor, NASBA and nested PCR appeared more sensitive than one-stage PCR and branched-DNA. It is concluded that new procedures have satisfactory sensitivity and specificity and could advantageously replace the conventional PCR procedures for the routine qualitative detection of serum HCV RNA.

Base Sequence↗
PubMed1995

Albumin batches and B19 parvovirus DNA.

BACKGROUND: B19 parvovirus (B19) may be transmitted iatrogenically by blood, and its prevalence in blood donations is estimated at 1 in 3,300 to 1 in 50,000. As a large number of blood donations make up the plasma pools used to produce plasma derivatives, even a virus as rare as B19 in a population of blood donors may result in the frequent contamination of plasma batches. The percentage of albumin batches containing B19 DNA has never been determined. STUDY DESIGN AND METHODS: The presence of B19 DNA was investigated by a polymerase chain reaction assay (with a primer pair in the VP1 region) in a total of 12 and 17 batches of 4- and 20-percent albumin, respectively, from two different manufacturers. RESULTS: No B19 DNA was detected in the batches tested. CONCLUSION: The current fractionation process used to obtain these albumin preparations is seen to allow the efficient degradation and/or elimination of B19.

Base Sequence↗
PubMed1995

Use of digoxigenin-labelled probes for the detection of B19 parvovirus DNA in batches of blood products.

Being thermostable and non lipid-enveloped, the B19 parvovirus cannot be destroyed by the chemical and physical treatments presently used to inactivate lipid-enveloped viruses such as HIV, hepatitis C and B viruses in plasma derivatives. A polymerase chain reaction assay was used to detect B19 parvovirus DNA. Amplified products were detected through a non-radioactive technology based on the use of a digoxigenin-labelled probe. B19 parvovirus DNA was detected in 20% of the studied batches of factor coagulation concentrates and in none of the albumin batches.

Blood↗
PubMed1994

B19 parvovirus DNA in solvent/detergent-treated anti-haemophilia concentrates.

A transfusional B19 parvovirus infection may have severe consequences in immunocompromised hosts. The presence of B19 DNA was investigated with a polymerase chain reaction (PCR) assay in 30 batches of solvent/detergent-treated clotting factor concentrates (12 batches of factor VIII, 16 batches of factor IX, 1 batch of factor VII, and 1 batch of PPSB). B19 DNA was detected in 6 (20%) batches, including 3 factor VIII and 3 factor IX concentrates. Because of the frequency of B19 DNA in batches of clotting factors, measures to prevent transfusional risk of B19 infection via these blood products are justified, especially in recipients immunocompromised by HIV infection.

Blood Coagulation Factors↗
PubMed1994

Provirus copy number to predict disease progression in asymptomatic human immunodeficiency virus type 1 infection.

To evaluate the prognostic value of provirus copy number through quantitative DNA polymerase chain reaction (PCR) in early stages of human immunodeficiency virus type 1 (HIV-1) infection, 42 untreated and asymptomatic HIV-1-seropositive subjects with baseline CD4+ cell counts > 200 x 10(6)/L were included in a prospective study and followed over a median of 27 months. Disease progression was defined as decrease in CD4+ cells to < 200 (14 events). At enrollment, provirus copy number was associated with CD4+ cell count and percentage, serum IgA, and p24 antigenemia. Elevated provirus copy number above 20 allowed identification of patients at high risk of a subsequently decreasing CD4+ cell count, even after adjusting for baseline CD4+ cell count (P = .003). Measuring provirus copy number by PCR at early stages of HIV-1 infection could offer a useful early means to predict progression to AIDS.

Adult↗
PubMed1994

Prenatal diagnosis for the unstable CTG repeat sequence in myotonic dystrophy: a retrospective study in a French family.

The results of DNA analysis for the unstable CTG repeat are reported in a french family of myotonic dystrophy. This retrospective study confirms results obtained previously with a linked DNA marker, using the CTG repeat DNA sequence in the same family. The demonstrated possibility of predicting phenotype as well as genotype in prenatal diagnosis is important for such a disorder, were subjects may be severely affected.

Adult↗
PubMed1993

Human T-cell lymphotropic virus type I and II DNA amplification in seropositive and seronegative at-risk individuals.

To determine the presence or the absence of human T-lymphotropic virus type I and/or II (HTLV-I/II) DNA in at-risk individuals who were persistently negative for specific serologic assays, polymerase chain reaction with two primer pairs in common and conserved regions of HTLV-I and -II genomes was used. Seronegative individuals at risk for HTLV-I/II infection (15 heterosexual partners of seropositive individuals, 17 breastfed children born to HTLV-I-infected mothers, 47 multiply transfused patients, 22 intravenous drug users) were studied (n = 101); 35 seropositive individuals and 25 seronegative low-risk individuals were used as positive and negative controls, respectively. No positive polymerase chain reaction was observed in the seronegative at-risk individuals or in the negative controls. Positive controls gave positive results with at least one primer pair in all cases except one. A latent HTLV-I/II infection with a persistently negative serologic test for HTLV-I/II seems unlikely.

Adolescent↗
PubMed1992

Human T lymphotropic virus (HTLV) type I and II DNA amplification in HTLV-I/II-seropositive blood donors of the French West Indies.

To confirm the presence of DNA from human T lymphotropic virus type I (HTLV-I), HTLV-II, or both in individuals found HTLV-I/II-positive through systematic screening of blood donations in Guadeloupe (French West Indies), 42 blood donors repeatedly positive for HTLV-I/II by ELISA were studied by polymerase chain reaction (PCR). Three primer pairs (env, pol, tax) targeted on conserved regions of HTLV-I or -II sequences (or both) and six probes (two generic, two HTLV-I-specific, two HTLV-II-specific) were used in a multiplex PCR. HTLV-I sequences were detected in 31 individuals (74%). All 31 subjects positive by Western blot (WB) harbored HTLV-I sequences. Fifteen individuals (48%) were positive with the three primer pairs used, 10 (32%) with two, and 6 (20%) with one. Subjects indeterminate or negative by WB were all negative by PCR. No HTLV-II sequences were detected with specific probes. The results indicate the absence of HTLV-I and -II infection in individuals with indeterminate WB, the presence of HTLV-I DNA in individuals positive for WB in the French West Indies, and the absence of HTLV-II infection in the cohort.

Adult↗