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Biomedical subjects

M Mariotti

Publications and source records attributed to M Mariotti.

At least 73 records · Page 4Linked to original sources
PubMed1992

Multicentre quality control of polymerase chain reaction for detection of HIV DNA.

OBJECTIVE: Seven French laboratories tested the specificity and sensitivity of the polymerase chain reaction (PCR) for the detection of HIV-1 DNA. METHODS: Following its own PCR protocols, each laboratory independently tested blind two panels of 20 coded peripheral blood mononuclear cell samples collected from HIV-1-seropositive individuals and from HIV-1-seronegative individuals at high or low risk of HIV infection. For the first panel, laboratories were free to select type and number of primers; for the second, all were required to use the two primer pairs Pol 3/4 and MMy 9/10' (Nef 1). RESULTS: False-positive and false-negative results were observed in all laboratories (concordance with serology ranged from 40 to 100%). In addition, the number of positive PCR results did not differ significantly between high- and low-risk seronegatives. The use of crude cell lysates in DNA preparation produced the same PCR results as phenol-extracted DNA. Discrepancies between laboratories indicated that factors other than primer pairs contributed strongly to laboratory variability. CONCLUSIONS: Our results emphasize the importance of both positive and negative controls in PCR and demonstrate the value of multicentre PCR quality control.

Base Sequence↗
PubMed1992

Towards a new predictor of AIDS progression through the quantitation of HIV-1 DNA copies by PCR in HIV-infected individuals.

The proviral copy (PVC) number in peripheral blood mononuclear cells (PBMCs) of human immunodeficiency virus (HIV)-infected individuals was measured by a quantitative polymerase chain reaction (PCR) assay to determine over time the relation between the viral load and the evolution towards the disease in HIV-infected people: 67 anti-HIV-1 positive individuals (60 stage II/III, 7 stage IV) were studied. The mean PVC number per 1.5 x 10(5) PBMCs in stage II/III individuals (14.4 +/- 14.2) and in stage IV individuals (32.2 +/- 22.9) was significantly different (P < 0.02). PVC number was inversely correlated to the CD4 lymphocyte count (P < 0.01). In the logistic regression, the PVC number was a better marker of evolution towards the disease than the CD4 lymphocyte count. The mean proportion of HIV-infected PBMCs in stage IV individuals and in stage II/III individuals was 1/4606 and 1/10714, respectively.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Quantification of HTLV-1 proviral copy number in peripheral blood of symptomless carriers from the French West Indies.

The development of human T-cell leukemia type 1 (HTLV-1) diseases are related to an increase in the proviral copy number (VCN) in peripheral blood mononuclear cells (PBMCs). Twenty symptomless anti-HTLV-1-positive blood donors, as well as four symptomatic individuals, all from the French West Indies, were studied. The VCN in PBMCs was determined by quantitative PCR. The VCN values for asymptomatic HTLV-1 carriers (range of less than 100 to approximately 9,500/micrograms of DNA) was nearly always less than the values for symptomatic carriers (range of approximately 5,500 to approximately 29,000/micrograms of DNA). Consequently, the proportion of HTLV-1-infected PBMCs in symptomless and in symptomatic individuals ranged from less than 1/1,500 to approximately 1/16 and approximately 1/27 to approximately 1/5, respectively. No correlation could be found between VCN and age or sex, suggesting the importance of factors other than age and sex as influences on the VCN number.

Adult↗
PubMed1991

No evidence of HIV-1 infection in seronegative hemophiliacs and in seronegative partners of seropositive hemophiliacs through polymerase chain reaction (PCR) and anti-NEF serology.

We prospectively studied a well-characterized cohort including 60 seronegative hemophiliacs or von Willebrand's disease patients, 6 seronegative female sexual partners of seropositive hemophiliacs, 59 seropositive hemophiliacs or von Willebrand's disease patients and 2 seropositive partners of seropositive hemophiliacs (used as positive controls), and 117 seronegative low risk individuals (used as negative controls). PCR assay, performed in peripheral blood mononuclear cells using three primer pairs in the gag, pol, LTR regions, showed no positive results in the 60 seronegative patients, in the 6 seronegative partners of seropositive patients and in the 117 seronegative low risk individuals, while PCR was positive with at least one primer pair in 53 (87%) of 61 seropositive patients. Anti-nef serology (Western-blot) was negative in seronegative patients, in seronegative partners of seropositive patients and positive in 58% out of the seropositive individuals. These results strongly suggest an absence of HIV-1 infection in individuals with a lastingly negative HIV serology.

Base Sequence↗
PubMed1991

No evidence of HTLV-I infection in French patients with multiple sclerosis using the polymerase chain reaction.

The polymerase chain reaction (PCR), using three primer pairs in the pol, tax, and env regions of the HTLV-I genome, was unable to detect HTLV-I in the blood samples of 54 caucasian subjects with multiple sclerosis who were seronegative for HTLV-I/II. Seventeen HTLV-I/II seropositive (by ELISA and Western blot) subjects used as positive controls were positive with the three primer pairs. The PCR was negative in 47 healthy HTLV-I/II seronegative (by ELISA) subjects at low risk of HTLV-I infection used as negative controls. These results suggest that there is no association between the occurrence of HTLV-I sequences and the development of multiple sclerosis.

Adult↗
PubMed1991

Polymerase chain reaction (PCR) in various stages of HIV infection. Relationship to disease progression.

In order to establish whether the Polymerase Chain Reaction (PCR) may constitute a new marker of evolution towards AIDS in symptomless HIV infected subjects, we used PCR with three primer pairs (in the gag, pol and LTR regions) in 223 seropositive individuals at different stages of HIV infection. Among 176 symptomless seropositive individuals, 174 (98.8%) were positive with at least one primer pair. The subjects negative with at least one primer pair had a CD4 lymphocyte count significantly higher (p less than 0.01), and serum immunoglobulin G, immunoglobulin A, neopterin and beta-2-microglobulin concentrations significantly lower (p less than 0.01) than the individuals positive with the three primer pairs. Among 73 seropositive individuals followed over a two year period, 59 presented the same PCR pattern over this time period, while PCR showed different results in 14. Forty-seven AIDS patients were positive with the three primer pairs. The number of PCR negative with at least one primer pair was significantly fewer (p less than 0.001) in symptomatic individuals than in symptomless individuals. We conclude that the percentage of positive PCR results in HIV infected individuals is linked to the clinical stage of infection and to the disease progression.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Free radical-induced lipoperoxidation and severe head injury. A clinical study.

Ten severely head injured patients (GCS less than or equal to 8), aged 17-62 years, were studied in order to investigate the role of lipoperoxidation in secondary brain damage. No patients had intracranial mass lesions, shock, hypoxemia, fever or sepsis. Blood samples were taken from the jugular bulb and from the right atrium, and thiobarbituric acid reacting substances (TBARS) were measured in plasma by spectrophotometry. Arterio-jugular venous oxygen differences (AVDO2) were obtained in seven patients, in order to estimate cerebral blood flow. Jugular TBARS (TBARSj) were always elevated (from To, to 2 h after injury) and correlated in a linear fashion with TBARS of right atrium (TBARSv): r = 0.74, p less than 0.001. TBARSj and AVDO2 are closely correlated, in accordance with an exponential function (R = 0.45, p less than 0.001) which describes how any cerebral perfusion derangement determines high levels of TBARSj, confirming lipoperoxidation as a key factor in the final common pathway of secondary posttraumatic brain damage.

Adult↗
PubMed1990

Failure to detect evidence of human immunodeficiency virus type 1 (HIV-1) infection by polymerase chain reaction assay in blood donors with isolated core antibodies (anti-p24 or -p17) to HIV-1.

Individuals with isolated and persistent core antibodies (anti-p24 or -p17) to HIV-1 are sometimes diagnosed through the systematic screening of blood donations. The significance of such serum reactivities remains unknown. Polymerase chain reaction (PCR) is a new technique allowing the direct detection of HIV-1 DNA in blood samples. In this study, PCR was used to detect HIV-1 DNA in 20 individuals with isolated and persistent core antibodies (14 anti-p24 and 6 -p17), in seven sexual partners of these individuals, in 55 HIV-1-seropositive individuals (positive controls), and in 105 HIV-1-seronegative blood donors at low risk of HIV-1 infection (negative controls). No HIV-1 DNA was detected in individuals with isolated and persistent core antibodies, in their sexual partners, or in negative control individuals, although PCR was positive in 54 of 55 seropositive control individuals. These results strongly suggest that individuals with isolated and persistent core antibodies are not infected with HIV-1.

Amino Acid Sequence↗
PubMed1990

DNA amplification of HIV-1 in seropositive individuals and in seronegative at-risk individuals.

We assessed the HIV-1 status of seropositive and seronegative at-risk individuals by the polymerase chain reaction. Fifty-four out of 55 HIV-1-seropositive samples scored positive. However, HIV-1 proviral DNA was not detected in 16 seronegative homosexuals, 20 seronegative polytransfused haemophiliacs and 20 seronegative thalassaemic children, 20 individuals with isolated and persistent anti-core antibodies and 74 seronegative blood donors. These data indicate that positive HIV-1 DNA is likely to be an exceptional phenomenon in HIV-seronegative people.

Adult↗
PubMed1990

Absence of HIV DNA sequences in seronegative polytransfused thalassemic patients.

The risk of infection with human immunodeficiency virus (HIV) by transfusion is not totally eliminated, since contaminated blood given before seroconversion to HIV is not detected on the actual biological screening. We used the polymerase chain reaction (PCR) assay (with one primer pair in the gag region and two in the pol region) to detect HIV DNA sequences in 30 seronegative polytransfused thalassemic patients and in 60 seropositive individuals (used as positive controls). We did not observe PCR-positive HIV-antibody-negative results in seronegative polytransfused patients.

Adolescent↗
PubMed1989

Responses of VPL thalamic neurones to peripheral stimulation in wakefulness and sleep.

In unanaesthetized, undrugged, normally respiring cats extracellular recordings were obtained from ventroposterolateral thalamic units through different states of the sleep-waking cycle. An air-puff peripheral stimulation was used to activate the recorded neurones. State-dependent changes of the response of thalamic neurones were shown, comparing slow-wave sleep (SWS) to wakefulness (W). During SWS an increase was observed in the strength of the discharge suppression, which follows the excitatory peak in the typical response pattern. Also the cell excitability is further reduced in slow-wave sleep during the 150-200 ms period following an excitatory response, suggesting that an enhancement of the post-excitatory inhibition could be involved in the generation of the slow 5-6 Hz rhythms, observed during thalamic and cortical synchronization.

Action Potentials↗
PubMed1989

Binding sites for [3H]2-oxo-quazepam in the brain of the cat: evidence for heterogeneity of benzodiazepine recognition sites.

In the present study, the distribution of benzodiazepine recognition site subtypes in the brain of the cat was investigated. To this aim, the binding properties of [3H]2-oxo-quazepam ([3H]2OXOQ) and [3H]beta-CCE, two ligands with preferential affinity for Type I benzodiazepine recognition sites, were compared to binding parameters for [3H]flunitrazepam ([3H]FNT) in different areas of the cat brain. The ratio of [3H]2OXOQ to [3H]FNT binding sites indicated that, in the cerebellum, Type I sites accounted for 90% of the total number of benzodiazepine recognition sites. The cerebral cortex, thalamus and mesencephalic reticular formation had also a high proportion of Type I sites (73-78%), whilst the two subtypes were almost equally distributed in the hippocampus, amygdala and bulbar reticular formation. A similar distribution of subtypes of benzodiazepine recognition sites was indicated by the ratio of [3H]beta CCE to [3H]FNT binding sites for different areas of the brain. These results demonstrate the existence of heterogeneity of recognition sites for benzodiazepines in the brain of the cat and support the view that [3H]2OXOQ preferentially labels Type I sites.

Animals↗
PubMed1989

The role of the right hemisphere in recovery from aphasia. Two case studies.

We report two female patients who became global aphasic following a large left hemisphere lesion. With passage of time they recovered to a considerable extent, but three years and six months, respectively, after the former CVA, a new stroke lateralized to the right hemisphere occurred and they showed a definite worsening of language disturbances. Possibilities and limits of the right hemisphere in "taking over" language functions are discussed.

Aphasia↗