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Biomedical subjects

M Mariotti

Publications and source records attributed to M Mariotti.

At least 37 records · Page 2Linked to original sources
PubMed1999

Prevalence of GB virus type C/hepatitis G virus RNA and of anti-E2 in individuals at high or low risk for blood-borne or sexually transmitted viruses: evidence of sexual and parenteral transmission.

BACKGROUND: The first epidemiologic evidence of GB virus type C (GBV-C)/hepatitis G virus (HGV) infection showed a high prevalence of asymptomatic carriers in blood donors and in populations at risk for blood-borne viruses. However, by using only viral RNA polymerase chain reaction, those studies underestimated the true spread of GBV-C/HGV infection. The combined detection of GBV-C/HGV RNA and of anti-E2 (which reflects recovery from infection) is necessary to define accurately the prevalence of GBV-C/HGV. STUDY DESIGN AND METHODS: The presence of both anti-E2 and GBV-C/HGV RNA was searched for in 1438 serum samples collected from various groups of individuals at low or high risk for blood-borne or sexually transmitted viruses (blood donors, organ donors, unselected pregnant women, immunocompetent or immunodepressed multiply transfused patients, HIV-positive or HIV-negative homosexual men, intravenous drug addicts). RESULTS: The presence of GBV-C/HGV RNA and/or anti-E2 (exposure to GBV-C/HGV) was frequent in populations at risk for blood-borne or sexually transmitted viruses. GBV-C/HGV appeared also to be sexually transmitted, with transmission from male to female more efficient than vice versa. A particularly elevated level of exposure to GBV-C/HGV was observed in homosexual men. In immunocompetent individuals, the prevalence of anti-E2 was about twice that of GBV-C/HGV RNA, which suggests the frequency of recovery from GBV-C/HGV infection. Most of the GBV-C/HGV RNA-positive individuals had no biochemical evidence of liver damage. CONCLUSIONS: GBV-C/HGV is frequent in populations at risk for blood-borne or sexually transmitted viruses. GBV-C/HGV is not a hepatitis virus, and it seems appropriate to rename it.

Alanine Transaminase↗
PubMed1999

Carriage of GB virus C/hepatitis G virus RNA is associated with a slower immunologic, virologic, and clinical progression of human immunodeficiency virus disease in coinfected persons.

The prevalence of GB virus C (GBV-C) infection is high in human immunodeficiency virus (HIV)-infected persons. However, the long-term consequences of coinfection are unknown. HIV-positive persons with a well-defined duration of infection were screened on the basis of their GBV-C/hepatitis G virus (HGV) RNA status and studied. GBV-C/HGV viremia was observed in 23, who carried the virus over a mean of 7.7 years. All parameters (survival, CDC stage B/C, HIV RNA load, CD4 T cell count) showed significant differences in terms of the cumulative progression rate between persons positive and negative for GBV-C/HGV RNA. When GBV-C/HGV RNA-positive and -unexposed subjects were matched by age, sex, baseline HIV RNA load, and baseline CD4 T cell count, HIV disease progression appeared worse in GBV-C/HGV RNA-negative subjects. The carriage of GBV-C/HGV RNA is associated with a slower progression of HIV disease in coinfected persons.

Adult↗
PubMed1999

Plasma human immunodeficiency virus RNA below 40 Copies/mL is rare in untreated persons even in the first years of infection.

To clarify the frequency and prognostic significance of a plasma human immunodeficiency virus (HIV) RNA load below the detection threshold during the natural history of infection, an ultrasensitive assay was used to identify persons with low virus loads in a cohort of 111 untreated subjects with a known date of seroconversion. Six persons had HIV RNA loads <40 viral copies (VC)/mL during the first years of HIV infection. The probability of meeting the criteria for long-term nonprogression was higher in these subjects (P=.043). However, a virus load <40 VC/mL was rare during the natural history of infection, even during the first years of symptomless HIV carriage. Such data confirm the general trend of disease progression in the entire population of HIV carriers.

Adult↗
PubMed1998

EDF-1, a novel gene product down-regulated in human endothelial cell differentiation.

Endothelial cell differentiation is a crucial step in angiogenesis. Here we report the identification of EDF-1, a novel gene product that is down-regulated when endothelial cells are induced to differentiate in vitro. The cDNA encoding EDF-1 was isolated by RNA fingerprinting from human endothelial cells exposed to human immunodeficiency virus type 1 Tat, a viral protein known to be angiogenic. The deduced amino acid sequence of EDF-1 encodes a basic intracellular protein of 148 amino acids that is homologous to MBF1 (multiprotein-bridging factor 1) of the silkworm Bombyx mori and to H7, which is implicated in the early developmental events of Dictyostelium discoideum. Interestingly, human immunodeficiency virus type 1 Tat, which affects endothelial functions, and the phorbol ester 12-O-tetradecanoylphorbol-13-acetate and culture on fibrin gels, which promote endothelial differentiation in vitro, all down-regulate EDF-1 expression both at the RNA and protein levels. In addition, the inhibition of EDF-1 translation by an antisense anti-EDF-1 construct results in the inhibition of endothelial cell growth and in the transition from a nonpolar cobblestone phenotype to a polar fibroblast-like phenotype. These data suggest that EDF-1 may play a role in the regulation of human endothelial cell differentiation.

Amino Acid Sequence↗
PubMed1998

GABAergic and cholinergic basal forebrain and preoptic-anterior hypothalamic projections to the mediodorsal nucleus of the thalamus in the cat.

The present study examined projections of GABAergic and cholinergic neurons from the basal forebrain and preoptic-anterior hypothalamus to the "intermediate" part of the mediodorsal nucleus of the thalamus. Retrograde transport from this region of the mediodorsal nucleus was investigated using horseradish peroxidase-conjugated wheatgerm agglutinin in combination with peroxidase-antiperoxidase immunohistochemical staining for glutamic acid decarboxylase and choline acetyltransferase. A relatively large number of retrogradely-labelled glutamic acid decarboxylase-positive neurons are located in the basal forebrain, amounting to more than 7% of the total population of glutamic acid decarboxylase-positive cells in this region. Moreover, retrogradely-labelled choline acetyltransferase-positive cells are interspersed among glutamic acid decarboxylase-positive neurons, accounting for about 6% of the total choline acetyltransferase-positive cell population in the basal forebrain. The glutamic acid decarboxylase-positive and choline acetyltransferase-positive retrogradely-labelled neurons are distributed throughout several regions of the basal forebrain, including the medial septum, the diagonal band of Broca, the magnocellular preoptic nucleus, the substantia innominata pars anterior, the substantia innominata pars posterior, and the globus pallidus where only a few retrogradely-labelled neurons were seen. The choline acetyltransferase-positive mediodorsal-projecting neurons are morphologically different from the choline acetyltransferase-positive neurons in the basal forebrain, suggesting that those projecting to the mediodorsal nucleus are a small proportion of the cholinergic neuronal population in the basal forebrain. In the preoptic-anterior hypothalamus, many retrogradely-labelled glutamic acid decarboxylase-positive cells were found, amounting to more than 7% of the total population of glutamic acid decarboxylase-positive cells in this region. These retrogradely-labelled glutamic acid decarboxylase-positive neurons are distributed throughout the preoptic-anterior hypothalamus in a continuous line with those in the basal forebrain, including the lateral preoptic area, the medial preoptic area, the bed nucleus of the stria terminalis, and the anterior and dorsal hypothalamic areas. The highest percentage of mediodorsal-projecting GABAergic neurons is in the anterior lateral hypothalamus where more than 25% of the total population of glutamic acid decarboxylase-positive cells project to the mediodorsal nucleus of the thalamus. Overall, of the large population of retrogradely-labelled neurons in the basal forebrain and preoptic-anterior hypothalamus, a significant proportion are glutamic acid decarboxylase-positive neurons (> 60% in the basal forebrain and > 30% in the preoptic-anterior hypothalamus), while the choline acetyltransferase-positive neurons amount to a smaller percentage of the neurons projecting to the mediodorsal nucleus (< 13% in the basal forebrain and < 2% in the preoptic-anterior hypothalamus). These results provide anatomical evidence of direct GABAergic projections from the basal forebrain and preoptic-anterior hypothalamic regions to the "intermediate" part of the mediodorsal nucleus in the cat. This GABAergic projection field could be the direct pathway by which the basal forebrain directly modulates thalamic excitability and may also be involved in mechanisms modulating electroencephalographic synchronization and sleep through the "intermediate" mediodorsal nucleus.

Animals↗
PubMed1998

Screening blood donations for viral genomes: multicenter study of real-time simulation using pooled samples on the model of hepatitis C virus RNA detection.

BACKGROUND: The systematic screening for several blood-borne viral genomes in blood donations is a complementary safety measure planned or discussed by the national authorities of several countries. STUDY DESIGN AND METHODS: To appreciate the feasibility of such screening using pooled samples, a multicenter study of real-time simulation has been performed on the model of hepatitis C virus (HCV) infection. Four blood transfusion center laboratories and two research and diagnosis laboratories simultaneously screened, by several HCV RNA polymerase chain reaction assays, a panel of plasma sample pools of different sizes (500, 100, and 10 samples), collected from HCV-infected or HCV-uninfected blood donors. One viremic plasma was introduced in each pool. HCV RNA was detected by in-house polymerase chain reaction procedures or by standardized manual or semi-automated polymerase chain reaction assays. RESULTS: The results indicate the feasibility of sample pooling, which renders the screening for viral genomes by molecular biology techniques applicable in the short term and the importance of the experience of laboratory personnel in the use of molecular biology tools. CONCLUSION: The improvement of standardized assays needs to be continued, and training of laboratory staff members appears to be a crucial step before systematic screening of blood donations for viral genomes by molecular biology techniques can occur.

Blood Donors↗
PubMed1998

The risk of disease progression is determined during the first year of human immunodeficiency virus type 1 infection.

A cohort of 103 human immunodeficiency virus type 1 (HIV-1)-infected persons with well-defined dates of seroconversion were studied to determine whether baseline plasma HIV RNA loads 6-12 months after seroconversion have prognostic value. Baseline plasma virus loads had predictive value for the disease-free survival rate and for the survival rate. The level of baseline HIV RNA also had a strong negative predictive value for the CD4+ T cell count during the fifth year of infection: A baseline load >5 log was predictive of a CD4+ T cell count <500/mm3 5 years after infection. Baseline HIV RNA load was a CD4+ T cell-independent predictor of progression to death. The major finding was that the disease outcome for HIV-1-infected persons is already determined during the first year of infection.

Adult↗
PubMed1997

Natural history of GBV-C/hepatitis G virus infection through the follow-up of GBV-C/hepatitis G virus-infected blood donors and recipients studied by RNA polymerase chain reaction and anti-E2 serology.

The aims of this study were to determine the outcome and the natural history of GBV-C/hepatitis G virus (HGV) infection and to establish the frequency of acute or persistent infections in multiply-transfused individuals and blood donors. We used a GBV-C/HGV RNA polymerase chain reaction (PCR) and an assay evidencing antibodies to the envelop protein E2, which is considered a marker for virus clearance. Among 16 PCR-positive recipients, 11 were still positive for GBV-C/HGV RNA at the end of the study period; six of the 16 recipients were GBV-C/HGV infected during the study period and thus had a well-defined date of infection. The 16 patients were shown to carry GBV-C/HGV RNA over a mean period of 4.4 years, for a mean observational period (defined as the follow-up period since the first sample positive for GBV-C/HGV RNA) of 5.3 years. Within the limits of the study period, the patients with a well-defined date of infection were positive for GBV-C/HGV RNA during a mean period of 4.7 years. If defined by the presence of GBV-C/HGV RNA for at least 6 months, the persistent infection rate was 100% in this recipient cohort. Serum anti-E2 antibody was evidenced at least once in five (31.2%) recipients and, except in one case, became detectable after the loss of GBV-C/HGV RNA. Among the 11 blood donors, all were still positive for GBV-C/HGV RNA after a mean follow-up period of 7.7 months. The persistent infection rate was 100% in this donor cohort. Once acquired, the infection to GBV-C/HGV generally tends to persist in immunocompetent patients.

Adenovirus E2 Proteins↗
PubMed1997

Fibronectin modulates endothelial response to HIV type 1 Tat.

The normal function of the endothelium is impaired in HIV-1 infection. Disturbances of the local cytokines as well as the release of HIV-1 Tat by infected mononuclear cells play a role in endothelial dysfunction. We studied the effects of Tat on the human endothelial ECV cell line. In this system, Tat inhibited cell proliferation only in the presence of fibronectin as a culture substrate, whereas it did not modulate plasminogen activator activity, cell migration, or synthesis of fibronectin. Because amino acids 49-57 contains a nuclear translocation sequence, we also evaluated the potential intracellular role of Tat in tat-transfected ECV cells. tat transfectants showed inhibition of cell growth, unaffected cell migration and plasminogen activator activity, and a significant induction of the expression of fibronectin.

Blotting, Western↗
PubMed1997

Even individuals considered as long-term nonprogressors show biological signs of progression after 10 years of human immunodeficiency virus infection.

Despite a decade of human immunodeficiency virus (HIV) seropositivity, a few individuals termed as long-term nonprogressors (LTNPs) maintain a stable CD4+ T-cell count for a period of time. The aim of this study was to establish, through the sequential determination of all known predictors of HIV disease, the proportion of such patients having stringent criteria of true long-term nonprogression. Among 249 individuals who were HIV-infected and prospectively followed up over a 10-year period (1985 to 1995), 12 having a CD4+ T-cell count greater than 500/microL (LTNP I group) and 9 having a CD4+ T-cell count less than 500 but stable over time (LTNP II group) after at least 10 years of infection without intervention of antiviral therapy, were studied over the entire follow-up period. The plasma HIV RNA copy number and the serum concentrations of p24 antigen, each anti-HIV antibody, neopterin, beta-2-microglobulin, Immunoglobulin (Ig) G and IgA were determined every 18 months over the study period. Cellular and plasma viremias were cross-sectionaly assayed in all 21 patients. Only two patients had strictly no marker of progression over the follow-up period. They were the only ones who had, over the 10-year period, a viral copy number too low to be detected. The other patients had a viral copy number higher than 400/mL at at least one visit and increasing over the follow-up period, and they evidenced one or more markers of virological or immunological deterioration. Cellular viremia was positive in all patients but two, while plasma viremia was negative in all but one. The population of individuals termed as LTNPs is not virologically and immunologically homogeneous. The majority present biological signs of HIV disease progression. A new pattern of true LTNP can be drawn through stringent criteria based on the whole known predictors. This pattern appears to be rare in HIV-positive population.

Adult↗
PubMed1997

Virological and immunological data of AIDS patients treated by passive immunotherapy (transfusions of plasma rich in HIV-1 antibodies).

BACKGROUND AND OBJECTIVES: In human immunodeficiency virus (HIV) infections, passive immunotherapy can be carried out through infusions of virus-inactivated plasma from symptomless HIV-infected persons with abundant HIV antibodies. MATERIALS AND METHODS: We carried out a prospective, randomized, double-blind, controlled, passive immunotherapy study, which compared two groups. One received plasma rich in HIV antibodies, the other a standard seronegative plasma. RESULTS: Measurement of the plasma HIV RNA load showed in both groups a significant decrease in the mean viral copy number at the end of the first month, followed by an increase at the third month. Beyond the third months, a significant decrease in viral load was observed only in the treatment group. A significant difference in favor of the treatment group was observed for plasma viremia by HIV culture. For the cytokines involved in the viral replication and for the immune activation markers such as neopterin and beta 2-microglobulin, the biological analysis in plasma failed to show a significant difference in either group. Clinically, the treatment group benefited by delay in the appearance of the first AIDS-defining event and reduction in the cumulative incidence of such events. CONCLUSION: One possible interpretation is that passive immunotherapy affects plasma viral load, but there is no evidence that HIV-specific antibodies are exclusively responsible for the observed effects.

Acquired Immunodeficiency Syndrome↗
PubMed1997

Prevalence of hepatitis G virus RNA in French blood donors and recipients.

BACKGROUND: Recently, cases of chronic hepatitis were linked to the presence of genomic sequences of a newly described RNA virus termed hepatitis G virus (HGV) and belonging to the Flaviviridae family. STUDY DESIGN AND METHODS: The presence of HGV RNA was searched for by polymerase chain reaction in a population of blood donors and in patients who had received multiple blood component transfusions and/or intravenous immunoglobulin (IVIG) infusions. RESULTS: Twenty-one (4.2%) of 500 donors were positive for HGV RNA as were 21 (10.7%) of 196 nonimmunosuppressed patients who had received multiple transfusions of packed red cells, 4 (8.7%) of 46 common variable immune deficiency (CVID) patients who had received only IVIG, and 22 (24.7%) of 89 bone marrow transplant (BMT) patients who had received IVIG and cellular components. The proportion of HGV-positive individuals was significantly higher in the immunosuppressed recipients (CVID and BMT patients) than in the nonimmunosuppressed patients who were multiply transfused with packed red cells (p < 0.03). The proportion of HGV-positive individuals was significantly higher in the BMT patients who had received IVIG and cellular components than in the CVID patients who had received IVIG only (p < 0.03). Eight (17.0%) of the 47 HGV-positive recipients and 48 (16.9%) of the 284 HGV-negative recipients had a serum alanine aminotransferase level higher than the upper limit of normal (nonsignificant difference). The medical history of HGV-positive donors failed to reveal a particular at-risk event. The large majority of HGV-infected patients had a normal serum alanine aminotransferase level, and the proportion of patients with elevated alanine aminotransferase was the same in HGV-positive and in HGV-negative recipients. CONCLUSION: The pathological significance of HGV infection remains unelucidated, and the classification of HGV as a new hepatitis virus was perhaps premature.

Adult↗
PubMed1997

Full or partial seroreversion in patients infected by hepatitis C virus.

Cases of partial seroreversion have been reported in hemodialyzed or immunodepressed patients, but spontaneous clearance of viremia associated with a disappearance of specific antibodies or clearance while receiving therapy has not been precisely documented in immunocompetent hepatitis C virus (HCV)-infected persons. A longitudinal study of markers of HCV infection in a cohort of 178 multitransfused patients followed over an 8-year period was done to establish well-documented cases of partial or full seroreversion. Thirty (16.8%) of 178 patients were HCV-infected; among them, 5 had partial or full seroreversion. Seroreversion to an anti-HCV-negative state is characterized by a quantitative decrease in antibody. A seroreversion may be observed in three circumstances: spontaneously, induced by therapy, and in conjunction with human immunodeficiency virus infection. Long-term follow-up of seroreverters will establish whether they have definitively eradicated HCV from their systems.

Alanine Transaminase↗