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Biomedical subjects

N Lapointe

Publications and source records attributed to N Lapointe.

At least 55 records · Page 3Linked to original sources
PubMed1992

Neurological findings in HIV-infected children: a review of 49 cases.

Many HIV-infected children have neurological involvement. We present our observations in 49 cases, 58% of which had some form of clinical neurological impairment. Most of the patients affected (71%) presented with progressive encephalopathy, characterized by developmental delay with loss of acquisitions and cognitive decline, an impaired growth curve, microcephaly and corticospinal dysfunction. CT-scan imaging shows cerebral atrophy in all cases and basal ganglia calcifications in 29%. Non-specific abnormalities are found on the EEG in two-thirds of cases and in the CSF in slightly less than half the cases. Pathological studies sometime revealed HIV encephalitis or lateral corticospinal tracts degeneration. Neurological impairment secondary to vascular events, neoplasms or opportunistic infections were rare, especially when compared with the adult HIV population.

AIDS Dementia Complex↗
PubMed1992

Diagnosis of vertical HIV-1 transmission using the polymerase chain reaction and dried blood spot specimens.

We have used the polymerase chain reaction (PCR) to detect HIV proviral sequences in minute amounts of peripheral blood collected onto newborn screening blotters. Forty-three newborns, infants, and children of HIV-infected mothers were serially studied: dried blood spot (DBS) specimens were processed for PCR; serum was assayed for HIV antibodies, p24 antigen, and immunoglobulins; mononuclear cells were cultured and CD4 cells were quantitated by immunofluorescence. There was excellent agreement between the results of blood spot PCR, viral culture, and clinical and immunological indicators of HIV infection. Eighteen of 19 infected children tested positive by both PCR and culture, including six asymptomatic infants who were less than 10 weeks of age. As expected, p24 antigen capture assays were insensitive, detecting only 13 of the 19 infected children. One infected infant tested positive by PCR, but negative by culture and antigen. This infant was seropositive at 27 months and had pronounced hypergammaglobulinemia in association with non-specific symptoms. Twenty-four of the 43 infants were asymptomatic with normal immune profiles, declining antibody levels and no evidence of infection. These children tested repeatedly negative by PCR, culture, and p24 antigen assays. Our results indicate that DBS PCR is a sensitive, specific, and cost-effective alternative to viral culture for the early diagnosis (or exclusion) of perinatal HIV infection. DBS sampling opens the way for large-scale prospective studies to determine the exact rates of vertical HIV transmission in industrialized, as well as, nonindustrialized countries.

Child, Preschool↗
PubMed1991

Improved detection of HIV-1 envelope sequences using optimized PCR and inosine-substituted primers.

We describe inosine-substituted 'consensus' primers for the detection of HIV-1 envelope sequences by the polymerase chain reaction. The primers, modifications of SK68 and SK69, are highly specific (100%) and sensitive (greater than 94%) and they prevent false-negative results due to variation in the HIV-1 genome. Consensus primers are needed to ensure the detection of most, if not all, variants of HIV-1 including American, African and newly emerging strains.

AIDS-Related Complex↗
PubMed1990

HIV infection among Quebec women giving birth to live infants.

This is the first anonymous unlinked seroprevalence study in Canada to use serum samples from newborns to determine the seroprevalence rate of human immunodeficiency virus (HIV) infection among childbearing women. Of the 68,808 samples tested 42 were confirmed as positive, for an overall crude seroprevalence rate of 6.1 per 10,000 live births (95% confidence interval [CI] 4.4 to 8.3), or 1 woman in 1638. Women who lived on Montreal island had an overall rate of 17.9 per 10,000 live births (95% CI 12.2 to 25.4), or 1 woman in 559. We observed a significant association between revenue index and seroprevalence; the rates were as high as 46.4 per 10,000 live births (95% CI 18.7 to 95.3), or 1 woman in 216, for Montreal island postal code areas with revenue indexes 20% or more below the provincial median. Extrapolation of the data suggested that 56 women with HIV infection gave birth to a live infant during 1989 in Quebec. Even though attempts to generalize the data from childbearing women to women of childbearing age have an inherent conservative bias, the results of our study suggest that 988 women (95% CI 713 to 1336) aged 15 to 44 years in Quebec had HIV infection in 1989. The actual number is likely substantially higher. The need for well-designed, creative interventions to prevent further HIV transmission to women is evident. Planning for the provision of medical and psychosocial services sensitive to specific needs of women who are already infected should start immediately.

Adolescent↗
PubMed1990

5-azacytidine and 5-azadeoxycytidine inhibit human immunodeficiency virus type 1 replication in vitro.

Chemotherapeutic agents which affect the integration, stability, or inducibility of the human immunodeficiency virus (HIV) provirus would have considerable value in treating acquired immunodeficiency syndrome. Two nucleoside analogs of cytosine, 5-azacytidine and 5-azadeoxycytidine, which seem to have such value because of their capabilities to affect both the stability and the methylation patterns of the nucleic acids into which they are incorporated, were tested for their ability to inhibit the replication of HIV type 1 (HIV-1) in human CEM T cells in vitro. 5-Azadeoxycytidine (1 microM) completely inhibited HIV replication in CEM cells, by the criteria of reduced viral antigen expression and decreased supernatant reverse transcriptase activity, with little toxicity for the treated cells. 5-azacytidine (1 microM) also inhibited HIV replication, but less effectively. When added 2 or more h after CEM cells were infected with HIV-1, both 5-azacytosine derivatives were less effective than they were when added at the time of infection. Even 2 h of exposure to 5-azadeoxycytidine was sufficient for inhibition of HIV replication. Although long exposure to either analog at concentrations of 1 microM would result in pronounced cellular cytotoxicity, the the fact that short exposures to the same dose of drug inhibit HIV replication but are not toxic for the cells implies that cellular toxicity itself is not an important mechanism of the antiviral action of the analogs.

Antineoplastic Agents↗
PubMed1990

AIDS and the urinary tract.

A wide spectrum of renal diseases ranging from glomerulopathic lesions to tumors may be associated with HIV infection. This infection may also complicate the course of dialysis and renal transplantation. We review the renal complications of HIV infection.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Renal complications of acquired immunodeficiency syndrome in children.

A low incidence of renal disease was noted in a retrospective analysis of pediatric patients with acquired immunodeficiency syndrome. Episodes of acute renal failure were attributable to dehydration or nephrotoxicity. One patient, however, had nephrosis with focal glomerular sclerosis. Focal sclerosis involving 10% to 20% of glomeruli was evident in autopsy tissue from three patients.

Acquired Immunodeficiency Syndrome↗
PubMed1987

Pathogenicity of HIV in lymphatic organs of patients with AIDS.

HIV antigens were searched for in the thymus, lymph nodes, bone marrow, and spleen of AIDS patients, by means of immunofluorescence technique. Human IgG against HIV and monoclonal antibodies against viral gag P24 protein yielded strong cytoplasmic fluorescence of cells in sections of the thymus, lymph nodes and spleen. Some cells containing HIV antigens were morphologically multinucleated giant cells. They reacted with monoclonal antibodies against helper/inducer T-cells (OKT4+), and were complexed with antibody or with complement as demonstrated by double-staining immunofluorescence technique. A large number of inflammatory cells infiltrated the thymus in areas containing cells expressing HIV antigens. These studies demonstrated an association of HIV virus with cytopathic and immunopathogenic reactions in lymphatic organs of AIDS patients, and are consistent with previous results, as well as indicative of a primary aetiologic role for the virus.

Acquired Immunodeficiency Syndrome↗
PubMed1987

Myeloperoxidase deficiency with extensive candidal osteomyelitis of the base of the skull.

A 6-year-old girl had a 7-month history of headaches and painful torticollis. A CT scan of the mastoids showed extensive bone destruction of the base of the skull and C-1. Biopsies of the retropharyngeal area and of the anterior aspect of C-1 were performed: histopathologic findings were suggestive of mycotic infection and cultures were positive for Candida albicans. The child was treated successfully with amphotericin B. The immunologic evaluation demonstrated the absence of myeloperoxidase in the neutrophils.

Candidiasis↗
PubMed1986

Pathogens in children with severe combined immune deficiency disease or AIDS.

We evaluated the frequency and severity of illnesses caused by various microbial pathogens in 15 children with severe combined immune deficiency disease (SCID) and 8 with acquired immune deficiency syndrome (AIDS). There were 35 viral, 23 bacterial, 19 mycotic and 13 parasitic infections. Nineteen of the 23 patients died of infection; Pneumocystis carinii pneumonia, giant-cell pneumonia due to paramyxoviruses and various disseminated viral infections were responsible for most deaths in both groups. The emerging role of paramyxoviruses was illustrated by the fact that they were responsible for giant-cell pneumonia in seven patients. Viral enteric infections were frequent in both groups. The variety of infectious microorganisms and the severity of resulting illnesses in the patients with AIDS were similar to those in the patients with SCID.

Acquired Immunodeficiency Syndrome↗
PubMed1986

Detection of HTLV-III/LAV antigens in peripheral blood lymphocytes from patients with AIDS.

HTLV-III was searched for in frozen sections of peripheral blood lymphocytes obtained from AIDS patients by an immunofluorescence technique. Human IgG against HTLV-III/LAV and monoclonal antibodies against HTLV-III/LAV P 24 antigen, yielded a strong cytoplasmic fluorescence in frozen sections of the lymphocytes. Some cells containing HTLV-III antigens displayed multinucleated giant forms. They also reacted with monoclonal antibodies against helper/inducer T-cells (OKT4+), as demonstrated by direct double staining immunofluorescence. Similarly, complexes of immunoglobulins and C3 component of complement were also detected on HTLV-III/LAV Ag expressing lymphocytes. Immunofluorescence study of frozen sections of peripheral blood lymphocytes appeared to be a simple, fast and reliable method for detection of HTLV-III/LAV Ag in AIDS patients.

Acquired Immunodeficiency Syndrome↗
PubMed1986

Thymic epithelium in AIDS. An immunohistologic study.

The authors investigated by immunofluorescence the thymic epithelium from AIDS patients, using several structural and functional markers of this tissue. In AIDS thymus, the epithelial reticular pattern was lost; and instead, clusters of round or spindle-shaped cells (assessed by their keratin content) were found. In addition, regions of epithelial necrosis, with loss of cell limits, were frequently observed. Thymulin content was decreased, and a partial loss of differentiation antigens of the thymic epithelium was also detected. The authors showed the presence of immunoglobulins and elements of the complement system directly bound to AIDS thymic epithelium, but not in any of the controls studied, including thymuses from patients who died after a long period of agony. These data suggest that the thymic epithelium can be included among the target tissues in AIDS, possibly by an indirect mechanism of autoimmune destruction.

Acquired Immunodeficiency Syndrome↗