PubMed Health⌕ Search

Biomedical subjects

P Lebon

Publications and source records attributed to P Lebon.

At least 19 recordsLinked to original sources
PubMed1992

HIV replication during the first weeks of life.

Diagnosis of HIV infection among children born to HIV-positive mothers can be made in the first 12 months, but few studies have examined HIV status during the first weeks of life. In a prospective longitudinal study of 50 infants born to HIV-1 seropositive women, blood samples were obtained at birth and at 4-9 weeks and 5-9 months of age, and were tested for HIV-1 by the polymerase chain reaction (PCR), viral culture, and p24 antigen measurements. 16 were diagnosed as HIV-infected by the age of 4-9 weeks according to both PCR and culture; by contrast, infection could be detected in only 5 children at birth. No changes in HIV status were observed between 4-9 weeks and 5-9 months in the 44 children who could be retested. Perinatal HIV-1 infection can therefore be diagnosed in the first 2 months of life, either by PCR or viral culture. Our inability to detect HIV-1 infection at birth in almost 70% of babies subsequently found infected suggests an active replication of HIV during the first weeks of life. Our results might favour the hypothesis that transmission of HIV-1 takes place either at the end of pregnancy or at delivery.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Underestimation of the incidence of measles in a population of French children.

Data on titres of specific antibodies against measles virus and information given by families and physicians were analysed in 133 vaccinated and 117 unvaccinated children. Only 2 of the 133 vaccinated children reported a history of measles, while 131 had detectable levels of antibodies. Measles antibodies were detected in 102 (87.2%) of the unvaccinated children, but a history of measles diagnosed clinically by a physician was reported in only 42 of them. These findings suggest that subclinical cases of measles are possible and contribute to the high circulation of the measles virus in the child population in France.

Adolescent↗
PubMed1992

Immunogenicity of combined anti-HIV and anti-suppressive vaccine preparations.

HIV-1 antigens generate in man both a humoral and cellular immune reaction. However, in ARC/AIDS patients, the cellular response is inhibited by HIV-1 which induces an antiproliferative (suppressive) effect on activated T cells. To overcome this inhibition and up-regulate the cellular response, we designed a new vaccine strategy directed both against HIV-1 and immunosuppression and we used an immunizing preparation composed of HIV-1 antigens combined with immunoregulatory peptides prepared in a biologically inactivated but immunogenic form. In mice, this preparation induced anti-HIV-1 antibodies and a cell-mediated cytotoxicity directed against H2 restricted cells carrying HIV-1 antigens.

Animals↗
PubMed1992

Absence of intrathecal synthesis of some interferon-alpha subtypes in bacterial meningitis.

Sixty-five cerebrospinal fluid (CSF) samples from 54 infants and children with bacterial meningitis were analyzed for the presence of interferon (IFN)-alpha with a biologic assay. Of the 65 samples, 3 were positive (2-4 IU/mL) and only 1 of 56 collected early was at 4 IU/mL. These results suggest that some subtypes of IFN-alpha already reported as present in viral infections of the central nervous system are not detected in bacterial meningitis by our IFN assay. This difference may be helpful in differentiating bacterial from viral infections and also in evaluating the quality of the virologic investigation; moreover, the rarity of IFN-gamma in CSF in bacterial meningitis needs further investigation to understand its role in the pathogenesis of the disease.

Child↗
PubMed1992

[Immunity to and incidence of measles in a population of Parisian children].

BACKGROUND: Measles remains prevalent in France despite the development of nationwide vaccination program. This study evaluates measles immunity and correlates it with active immunization. MATERIAL AND METHODS: A total of 250 (131 boys and 119 girls) French children, aged 2 to 15 years, seen as outpatients in our hospital, were studied from 1.01.90 to 1.06.91; 133 had received live measles vaccine during the 2nd year of life, the 117 others were not vaccine-protected. Evaluation included medical records, specially those concerning past-history of measles or measles-like diseases and immunizations. Measles IgG and IgM antibodies (ELISA) were looked for in all 250 children. RESULTS: 102 of the 117 children who were not vaccine-protected had a detectable antibody titer. 42 of these 102 had a history of measles, before the age of 5 years in 30, between 5 and 10 years in 9 and after the age of 10 years in 3. Only 4 of the 70 children aged over 10 years and not vaccine-protected had no detectable antibodies. 131 of the 133 actively immunized children had detectable antibodies. CONCLUSIONS: Measles is probably more frequently subclinical than was believed until now. Its relative frequency in France in children who had not received the live vaccine explains the high percentage of those aged over 10 years who had detectable antibodies and the relatively low incidence of the disease in teenagers and young adults.

Adolescent↗
PubMed1992

[Cytomegalovirus infections in patients after liver transplantation: determination of risk groups].

The goal of this study was to identify high-risk groups for cytomegalovirus infection after liver transplantation. Sixty-one patients were evaluated. Twenty-five patients (41 percent) had infection. Among the 16 patients who were seronegative for the virus before transplantation, 11 received a liver graft and blood products from seronegative donors and none of them developed infection. All seronegative recipients of a liver from seropositive donors (5/5) developed primary infection. Among the 45 patients seropositive before transplantation, 20 developed a cytomegalovirus infection, whatever the donor serologic status. The incidence of symptomatic reactivation or reinfection was high (14/20), and, for 12/14 of them, associated with early acute rejection. Two high-risk groups of patients, eligible for cytomegalovirus prophylaxis, were identified: seronegative recipients of seropositive donors and seropositive recipients with early acute rejection.

Adolescent↗
PubMed1992

[Neonatal herpes: recurrence after treatment with acyclovir].

A case of cutaneous herpes relapse with meningitis is reported in a 1.5 month-old infant treated during the first three weeks of life with acyclovir (ACV) for a neonatal herpes infection. Such a relapse has previously been described in older children as well as in adults. In this case report, there was immunological response to herpes virus infection, 2.5 months after the onset of the infection. The relapse is discussed taking into account the mechanism of action of ACV, the age of the patient and the immunological response profile. Because of the high risk of neurological involvement, we suggest that the relapse should be treated with ACV for a period of time longer than actually recommended.

Acyclovir↗
PubMed1992

Intrathecal synthesis of proteins: from immunoglobulins to prealbumin.

The assessment of proteins intrathecal synthesis (ITS) is an essential step in the CSF analysis. It can be established qualitatively by different ratios and quantitatively by empirical formulae. Schuller and Sagar's formula was proposed 10 years ago for the calculation of IgG ITS. From this calculation, the antibody specific activity of intrathecal immunoglobulins may be also evaluated. The same principle may be used for complement components and for different other CSF proteins. Two examples (concerning Fibronectin and prealbumin ITS) demonstrate the usefulness of this approach, which can be programmed by a computer.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Clinical and virological aspects of HIV2 infection in rhesus monkeys.

To establish an animal model of AIDS, two different "wild" or "adapted" HIV2 Rod and Eho strains were cultivated on monkey cells from different species (baboons, cynomolgus, Rhesus monkeys). Five different available strains were then injected both by intravenous (i.v.) and intracerebral (i.c.) route into ten Rhesus monkeys. Seven animals seroconverted between days 13 and 230. Reverse transcriptase activity in the lymphocyte culture supernatants was detectable in six of the seven animals that seroconverted, and in one animal that remained seronegative. Lymphopenia and a decrease in the CD4+ cell counts were observed in eight animals. One animal, inoculated with HIV2-Rod "wild type," developed a severe cachexia, with dyspnea, and associated neurological symptoms 150 days after inoculation. This animal was sacrificed on day 220. Pathological examination showed typical lesions of actinomycetes infection in the lungs and in the meninges. Another monkey had significant weight loss associated with lymphadenopathies and pancytopenia. These results suggest that in vivo replication of HIV2 in Rhesus monkeys may induce clinical symptoms of immune deficiency. This method is reproducible and may provide a good model for AIDS.

Animals↗
PubMed1992

Alpha-interferon therapy in a case of probable progressive multifocal leukoencephalopathy.

Probable progressive multifocal leukoencephalopathy (PML) was diagnosed on the basis of clinical picture and magnetic resonance imaging in a 63-year-old man with a complete remission of a non-Hodgkin's lymphoma. After the introduction of intramuscular alpha-interferon therapy, his neurological state and MRI findings showed a clear improvement. Eighteen months after the onset of first symptoms the patient has significantly recovered from both aphasia and motor impairment, and shows only a mild attentional deficit.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1991

Analysis of retroviral sequences in the spinal form of multiple sclerosis.

The polymerase chain reaction was used, in a blind study, to look for retroviral sequences in DNA extracted from the peripheral blood mononuclear cells of 11 patients with the spinal form of multiple sclerosis (MS). Control subjects consisted of 7 patients with other neurological diseases and 5 healthy blood donors. Three sets of oligonucleotides were used. They could detect all known human oncoretroviruses, lentiviruses, or spumaretroviruses. The primers recognized conserved sequences in the long terminal repeats of the proviral DNA. Control experiments showed that the primers crossreacted within the human immunodeficiency virus or human T-cell lymphotropic virus group and that they provided the expected level of sensitivity. Therefore the assay could have detected not only known human retroviruses but also new related members. In spite of this, no retroviral sequences were detected in either the MS or the control specimen.

Adult↗
PubMed1991

Intrathecal synthesis of IgG subclasses in multiple sclerosis and in acquired immunodeficiency syndrome (AIDS).

Serum and cerebrospinal fluid (CSF) of 50 neurological patients (24 multiple sclerosis (MS), ten acquired immunodeficiency syndrome (AIDS) and 16 other neurological diseases (OND)) and ten controls were analyzed by enzyme-linked immunosorbent assay (ELISA) for IgG subclass quantification and for the calculation of intrathecal synthesis (ITS). Total IgG was determined by two methods: electroimmunodiffusion (EID) and ELISA. A highly significant correlation was established between both methods. The existence of ITS was proved by the IgG/albumin ratio, the IgG index, Tourtellotte's formula, and Schuller's formula. In AIDS patients all IgG subclasses showed an increase in the CSF, whereas in sera only the IgG1 was significantly increased. CSF of MS patients showed a predominant increase of IgG1 whereas no significant modification of IgG subclasses was observed in sera. In most of the AIDS patients there was an ITS of IgG1, IgG3 and IgG4, but rarely (3/10) IgG2. In contrast, a polyclonal ITS of IgG was exceptional (1/24) in MS patients. No significant correlation could be established between clinical data and IgG subclass ITS in MS. The variations of each IgG subclass in serum and in ITS were not significantly correlated. Measurement of each IgG subclass and calculation of ITS seems essential in order to analyze any subclass antibody repertory inside the central nervous system.

Acquired Immunodeficiency Syndrome↗
PubMed1991

A phase I trial of 21-day continuous venous infusion of alpha-interferon at circadian rhythm modulated rate in cancer patients.

The toxicity and/or the stimulation of natural killer cell activity that resulted from exposure to alpha-interferon varied according to circadian dosing time, both in mice and in human beings. Ten patients with advanced renal cell carcinoma or melanoma were treated with recombinant alpha-interferon-2b using a continuous 21-day intravenous schedule at circadian modulated rate. Patients received 15-20 MU/m2/day in an ambulatory care program. The drug was delivered via an external programmable-in-time pump. Thirty-nine courses of therapy were given (2-12 courses per patient). Severe side effects included World Health Organization grade III somnolence (one patient, 1 course) and grade III-IV neutropenia (five patients, 10 courses). Karnofsky performance status decreased by 40% in 3 patients (five courses). Two of these patients were withdrawn from the study because of toxicity. Disease was stabilized in four of the seven patients evaluable for response. Seven of the 10 patients are alive at 15 months' median follow-up. Two have continued with chronotherapy for 9+ and 13+ months, respectively. A large interpatient variability characterized the maximally tolerated dose. Two patients led their usual activities while receiving 20 MU/m2/day for three courses or more. Conversely, two patients exhibited severe side effects with 10 MU/m2/day. As compared with schedules of standard administration or continuous flat infusion, this circadian schedule of infusion allowed a large increment in total daily dose and dose intensity. A starting dose of 15 MU/m2/day was well tolerated by 8 of 10 patients and can be recommended using this circadian modulated schedule.

Adult↗
PubMed1991

Amplification and characterization of herpesvirus DNA in cerebrospinal fluid from patients with acute encephalitis.

A single pair of oligonucleotide primers selected within a highly conserved region of the DNA polymerase gene of the herpesviruses was designed to amplify related viral genomes, i.e., herpes simplex virus type 1, herpes simplex virus type 2, Epstein-Barr virus, and cytomegalovirus, by the polymerase chain reaction. A simple restriction enzyme analysis of these amplified products allowed accurate characterization of the herpesvirus type. Ninety-nine cerebrospinal fluid samples from 36 patients (including newborns, children, and adults) with acute encephalitis were tested for the presence and identification of herpesvirus DNA by this approach. High levels of viral DNA, which were readily visualized by simple ethidium bromide staining, were found in all these patients from the first days of the disease and, in some cases, until the third week following the onset of acute encephalitis. The herpesvirus type was rapidly identified by enzymatic digestion in 33 patients' samples and by hybridization and direct sequencing in the last 3 patients' samples. Our results show that the polymerase chain reaction provides a highly sensitive and specific technique for the identification of herpesviruses DNA in cerebrospinal fluid that should be of value for early and rapid diagnosis, therapeutic decisions, prognostic evaluation, and epidemiological studies.

Acute Disease↗
PubMed1991

[Viral infection in the neonatal period: diagnostic difficulties, the role of interferon alpha levels].

Serum and/or cerebrospinal fluid (CSF) alpha interferon (aIFN) levels were determined in 31 neonates hospitalized for suspected sepsis. Final diagnosis was bacterial sepsis in 15, viral infection in 13 and no infection in 3. Among the 13 neonates with viral infection, enterovirus was isolated 5 times and coxsackievirus 4 times. No aIFN was found in cerebro-spinal fluid and/or serum among the neonates with bacterial sepsis or without infection. By contrast, in neonates with viral infection, CSF and/or serum aIFN levels were always elevated except in one case in which serum aIFN determination was not available. We conclude that in neonates, elevated levels of CSF and serum aIFN appear to be specific of viral infection, and that this might be helpful in the differential diagnosis of suspected sepsis.

Coxsackievirus Infections↗