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Biomedical subjects

P Lepage

Publications and source records attributed to P Lepage.

At least 37 records · Page 2Linked to original sources
PubMed2000

Molecular scanning of the human PPARa gene: association of the L162v mutation with hyperapobetalipoproteinemia.

Peroxisome proliferator-activated receptor alpha (PPARalpha) is a member of the steroid hormone receptor super family involved in the control of cellular lipid utilization. This makes PPARalpha a candidate gene for type 2 diabetes and dyslipidemia. The aim of this study was to investigate whether genetic variation in the human PPARalpha gene can influence the risk of type 2 diabetes and dyslipidemia among French Canadians. We therefore first determined the genomic structure of human PPARalpha, and then designed intronic primers to sequence the coding region and the exon-intron boundaries of the gene in 12 patients with type 2 diabetes and in 2 nondiabetic subjects. Sequence analysis revealed the presence of a L162V missense mutation in exon 5 of one diabetic patient. Leucine 162 is contained within the DNA binding domain of the human PPARalpha gene, and is conserved among humans, mice, rats, and guinea pigs. We subsequently screened a sample of 121 patients newly diagnosed with type 2 diabetes and their age and sex-matched nondiabetic controls, recruited from the Saguenay-Lac-St-Jean region of Northeastern Quebec, for the presence of the L162V mutation by a PCR-RFLP based method. There was no difference in L162 homozygote or V162 carrier frequencies between diabetics and nondiabetics. However, whether diabetic or not, carriers of the V162 allele had higher plasma apolipoprotein B levels compared to noncarriers (P 5 0.05). To further this association, we screened another sample of 193 nondiabetic subjects recruited in the greater Quebec City area. Carriers of the V162 allele compared with homozygotes of the L162 allele had significantly higher concentrations of plasma total and LDL-apolipoprotein B as well as LDL cholesterol (P </= 0.02). These results suggest an association between the PPARalpha V162 allele and the atherogenic/hyperapolipoprotein B dyslipidemia.

Animals↗
PubMed2000

[Reduction of perinatal transmission of HIV-1: antiretroviral prophylaxis and obstetrical interventions].

Incorporation of zidovudine prophylaxis (given to the mother during the third trimester of pregnancy and at delivery and to the newborn during the first 6 weeks of life) in clinical practice has substantially reduced the perinatal transmission of HIV-1 and the number of pediatric AIDS cases in industrialized countries. Rates of transmission of +/- 1% have been observed with the combination of antiretroviral prophylaxis and elective caesarean delivery. Elimination of perinatal transmission of HIV is therefore a feasible goal in Europe and the United States. Recent studies have identified less complex and less expensive preventive therapies more applicable to developing countries.

Anti-HIV Agents↗
PubMed1999

Serotonergic dysfunction in women with pure premenstrual dysphoric disorder: is the fenfluramine challenge test still relevant?

The fenfluramine (FEN) neuroendocrine challenge paradigm, which involves measuring the response of prolactin (PRL) release to an oral challenge dose of FEN, provides a means of assessing serotonin (5-HT) function. The purpose of this study was to ascertain the role of 5-HT in premenstrual dysphoric disorder (PMDD) by measuring: (1) PRL and cortisol (CORT) responses to FEN; and (2) platelet 3H-imipramine binding levels, in females with pure PMDD (without a past or present comorbid mood disorder) in comparison to healthy controls. FEN challenge tests were administered to nine female patients with pure PMDD and nine healthy female controls during the follicular and late luteal phases of a menstrual cycle. There were no differences in the PRL response to FEN for women with PMDD compared to healthy controls. However, the trend toward a delayed response to FEN and a significant negative correlation between delta(max) PRL and basal CORT in patients but not in controls during both phases of the menstrual cycle suggest an underlying 5-HT dysfunction in patients as compared to controls. This is further supported by the finding of significantly lower Bmax 3H-imipramine binding levels in the patients during the late luteal phase.

Journal Article↗
PubMed1999

Maternal humoral factors associated with perinatal human immunodeficiency virus type-1 transmission in a cohort from Kigali, Rwanda, 1988-1994.

OBJECTIVES: to study different parameters of humoral immunity responses in the serum of 39 human immunodeficiency virus type-1 infected pregnant women from Kigali, (Rwanda) in correlation with perinatal transmission. METHODS: this study was done between 1988 and 1994. Thirty nine HIV-1 infected women, 18 transmitting (T) and 21 non-transmitting (NT) mothers, have been chosen based on the quantity of sera available for analysis. Maternal data were collected at the time of delivery or during the preceding month. Quantification of viral load was performed by the signal amplification bDNA assay. Specific reactivity of antibody was tested against recombinant p24 protein and five different synthetic peptides from gp120 and gp41 based on HIV LAI-strain sequences. Neutralization assays were performed against laboratory (RII strain of the HIV-1 C subtype) and primary strains (two NSI and one SI of the HIV-1 A subtype). Antibody Dependent Cellular Cytotoxicity assay was performed with CEM.NK(R) cells against a laboratory HIV-1 strain. RESULTS: absence of correlation regarding maternal viral load, or viral subtype and vertical transmission was observed. By contrast, the CD4/CD8 ratio was significantly higher in non-transmitting mothers compared to transmitting mothers. Moreover, high anti-p24 antibody avidity was correlated with a lower risk of perinatal transmission. Furthermore, transmission risk appeared significantly higher with reactivity of serum samples to linear epitopes of gp41 (amino acids 566-582, 578-594), whereas risk appeared lower with reactivity to the immunodominant domain of gp41 (amino acids 597-609). No significant difference was observed in titres of antibody neutralizing primary isolates (two NSI (non syncitium inducer) and one SI (syncitium inducer) of the HIV-1 A subtype) and laboratory strain (RII strain, of the HIV-1 C subtype) between transmitting and non-transmitting mother's sera. In addition, titres of Antibody Dependent Cellular Cytotoxicity were similar in transmitting versus non-transmitting mothers. However, high Antibody Dependent Cellular Cytotoxicity titres were correlated with a good clinical status of children. CONCLUSIONS: three parameters such as high CD4/CD8 ratio, high anti-p24 antibody avidity and high reactivity against the immunodominant epitope of gp41 have been shown to be correlated with no perinatal transmission. High Antibody Dependent Cellular Cytotoxicity titres appeared to be linked to a good clinical status of children after birth. One parameter, reactivity against two linear epitopes of gp41, appeared to be correlated with vertical transmission.

Acquired Immunodeficiency Syndrome↗
PubMed1999

The return of tuberculosis.

At the end of the 20th century, tuberculosis remains a major public health issue. In developing countries tuberculosis is a leading cause of morbidity and mortality, and the spread of the HIV epidemic contributes significantly to the worsening of the situation. Coinfection with tuberculosis and HIV results in special diagnostic and therapeutic problems and uses up larger amounts of medical resources in developing countries. Outbreaks of multidrug resistant tuberculosis (MDR-TB) were first reported from US-American centers caring for HIV patients, but have now been observed in many other countries. In Western Europe the tuberculosis epidemic is under control, but increasing incidence rates in migrants raise new problems in these countries. Tuberculosis is uncontrolled in large parts of the former Soviet Union due to the socio-economic break-down in these countries. Only rigorous infection control measures on a world-wide scale will prevent further detoriation of this situation. Therefore, the extension of surveillance systems, and sufficient funding for the prevention, diagnosis, and treatment of tuberculosis by national governments and international organizations are all urgently needed.

AIDS-Related Opportunistic Infections↗
PubMed1999

Natural history of human immunodeficiency virus type 1 infection in children: a five-year prospective study in Rwanda. Mother-to-Child HIV-1 Transmission Study Group.

OBJECTIVE: To compare morbidity and mortality of human immunodeficiency virus type 1 (HIV-1)-infected and HIV-1-uninfected children and to identify predictors of acquired immunodeficiency syndrome (AIDS) and death among HIV-1-infected children in the context of a developing country. DESIGN: Prospective cohort study. SETTING: Maternal and child health clinic of the Centre Hospitalier de Kigali, Rwanda. PARTICIPANTS: Two hundred eighteen children born to HIV-1-seropositive mothers and 218 born to seronegative mothers of the same age and parity were enrolled at birth. OUTCOME MEASURES: Deaths, clinical AIDS, nonspecific HIV-related manifestations, and use of health care services. RESULTS: Fifty-four infected and 347 uninfected children were followed up for a median of 27 and 51 months, respectively. With the exception of chronic cough, the risk of occurrence of nonspecific HIV-related conditions was 3 to 13 times higher in infected than in uninfected children. The recurrence rate and severity of these findings were increased systematically in infected infants. Estimated cumulative risk of developing AIDS was 28% and 35% at 2 and 5 years of age, respectively. Estimated risk of death among infected children at 2 and 5 years of age was 45% and 62%, respectively, a rate 21 times higher than in uninfected children. Median survival time after estimated infection was 12.4 months. Early infection, early onset of HIV-related conditions, failure to thrive, and generalized lymphadenopathy were associated with subsequent risk of death and/or AIDS, whereas lymphoid interstitial pneumonitis was predictive of a milder disease. CONCLUSIONS: In Africa, HIV-1-infected children develop disease manifestations early in life. Specific clinical findings are predictive of HIV-1 disease, AIDS stage, and death. Bimodal expression of HIV-1 pediatric disease is encountered in Africa, as in industrialized countries, but prognosis is poorer. human immunodeficiency virus infection, children, vertical transmission, natural history, Africa.

AIDS-Related Opportunistic Infections↗
PubMed1998

Care of human immunodeficiency virus-infected children in developing countries. International Working Group on Mother-to-Child Transmission of HIV.

CONTEXT: There is urgent need to strengthen the area of pediatric HIV/AIDS care in developing countries. Clinical research in this area is also scarce. METHODOLOGY: A literature review and a postal survey were used to obtain updated information on mortality, morbidity and current standards of care of children born to HIV-infected mothers in developing countries. A 2-day workshop was organized to review the available data and to identify the key areas where clinical research should be conducted. MAIN FINDINGS: Rates of mortality and morbidity were very different from one study to another but generally higher than in industrialized countries. Prognostic studies for HIV-1-infected children in developing countries were not available. Based on the report of 14 teams from 11 countries, specific protocols for HIV-infected children with persistent diarrhea or severe malnutrition were documented in fewer than one-half of the cases. Secondary antimicrobial prophylaxis after interstitial pneumonia or recurrent infections was still infrequent, as primary prophylaxis of opportunistic infections. The following list of clinical research priorities was identified by the workshop participants: primary prophylaxis of opportunistic and bacterial infections; case management of persistent diarrhea; reassessment of the performance of p24 antigen for diagnostic and prognosis use; studies on the etiology of pulmonary infections; long term observational pediatric cohorts; current weaning practices and duration of breast-feeding; counseling and HIV testing of children and families; prevention of HIV sexual transmission in children and adolescents.

AIDS Serodiagnosis↗
PubMed1998

Mother-to-child transmission of HIV.

The first children with HIV-1 infection were described in 1983. As of 1998, the global HIV epidemic is having a profound impact on the health and survival of children. Almost all HIV infections among young children are due to vertical transmission, and the intrapartum period appears to provide us with a crucial window of opportunity for prevention. Postnatal transmission through breastfeeding also contributes an estimated one third to one half of vertical transmission worldwide. Carefully conducted epidemiologic studies are elucidating the immunologic, virologic, and behavioral factors affecting the risk of HIV-1 transmission from mother to infant and the natural history of HIV disease in perinatally infected children. Transmission of HIV-1 is influenced by many factors, and a high maternal viral load is insufficient to fully explain vertical transmission of HIV-1. Pediatricians and other providers should counsel HIV-infected women about the means available to decrease the risk of HIV transmission to the infant. However, the majority of HIV-infected children are born in the developing world, and a crucial challenge is to identify safe and effective interventions that are feasible in those countries with the most significant HIV burden.

Adult↗
PubMed1998

[Peripheral thrombopenic purpura associated with acquired toxoplasmosis].

Acquired Toxoplasma Gondii infection has a benign course in adults and children immunologically competent. Thrombocytopenia is much more common during congenital toxoplasma infection and the rare cases of purpura associated with acquired toxoplasmosis are usually not thrombocytopenic. We report a case of thrombocytopenic purpura in an immunocompetent child, associated with active acquired toxoplasmosis. In rare circumstances, acquired toxoplasmosis in an immunocompetent patient may be associated with severe thrombocytopenia. However, the low incidence of such cases makes a therapeutic consensus difficult.

Adult↗
PubMed1997

High-resolution linkage map in the proximity of the host resistance locus Cmv1.

The mouse chromosome 6 locus Cmv1 controls replication of mouse Cytomegalovirus (MCMV) in the spleen of the infected host. In our effort to clone Cmv1, we have constructed a high-resolution genetic linkage map in the proximity of the gene. For this, a total of 45 DNA markers corresponding to either cloned genes or microsatellites were mapped within a 7.9-cM interval overlapping the Cmv1 region. We have followed the cosegregation of these markers with respect to Cmv1 in a total of 2248 backcross mice from a preexisting interspecific backcross panel of 281 (Mus spretus x C57BL/6J)F1 x C57BL/6J and 2 novel panels of 989 (A/ J x C57BL6)F1 x A/J and 978 (BALB/c x C57BL/6J)F1 x BALB/c segregating Cmv1. Combined pedigree analysis allowed us to determine the following gene order and intergene distances (in cM) on the distal region of mouse chromosome 6: D6Mit216-(1.9)-D6Mit336-(2.2)- D6Mit218-(1.0)-D6Mit52-(0.5)-D6Mit194-(0.2)-Nkrp 1/ D6Mit61/135/257/289/338-(0.4)-Cmv1/Ly49A/D6Mit370++ +- (0.3)-Prp/Kap/D6Mit13/111/219-(0.3)-Tel/D6Mit374/290/ 220/196/195/110-(1.1)-D6Mit25. Therefore, the minimal genetic interval for Cmv1 of 0.7 cM is defined by 13 tightly linked markers including 2 markers, Ly49A and D6Mit370, that did not show recombination with Cmv1 in 1967 meioses analyzed; the proximal limit of the Cmv1 domain was defined by 8 crossovers between Nkrp1/ D6Mit61/135/257/289/338 and Cmv1/Ly49A/D6Mit370, and the distal limit was defined by 5 crossovers between Cmv1/Ly49A/D6Mit370 and Prp/Kap/D6Mit13/111/219. This work demonstrates tight linkage between Cmv1 and genes from the natural killer complex (NKC), such as Nkrp1 and Ly49A, suggesting that Cmv1 may represent an NK cell recognition structure encoded in the NKC region.

3T3 Cells↗
PubMed1996

Natural resistance to intracellular infections: Nramp1 encodes a membrane phosphoglycoprotein absent in macrophages from susceptible (Nramp1 D169) mouse strains.

The mouse Nramp1 gene (Bcg/Ity/Lsh) controls innate defense to infection with intracellular parasites such as Mycobacterium, Salmonella, and Leishmania. Sequence analysis of Nramp1 predicts a hydrophobic, membrane-associated protein expressed exclusively in monocyte/macrophage lineages. A single G169D substitution within the fourth predicted transmembrane domain of Nramp1 is associated with susceptibility to infection (Bcg) in inbred mouse strains. To initiate the biochemical characterization of the Nramp1 protein and to analyze the molecular basis of susceptibility associated with the Nramp1(D169) allele, oligopeptides derived from Nramp1 and two fusion proteins containing the first 54 and the last 35 residues of Nramp1 were used to raise specific anti-Nramp1 antisera. In addition, a c-Myc epitope (EQKLISEEDL) was introduced in-frame at the C terminus of Nramp1 to follow its expression in a yeast heterologous system. Western analysis of crude membrane fractions from yeast demonstrated that Nramp1 is indeed an integral membrane protein (resistant to urea extraction). In resident Bcg(r) (129sv, Nramp1(G169)) macrophages, one of the anti-Nramp1 antisera identified by immunoprecipitation a protein of 90,000 to 100,000 apparent m.w. that was absent in macrophages from knockout mice bearing a null mutation at Nramp1. The Nramp1 protein could be metabolically labeled with orthophosphate and was sensitive to glycosylase treatment, verifying that Nramp1 is an integral membrane phosphoglycoprotein. Parallel analysis of macrophage extracts from Bcg(s) mouse strains (C57BL6/J and BALB/c, Nramp1(D169)) failed to detect mature Nrampl protein in these cells, suggesting that the G169D mutation at Nramp1 prevents proper maturation or membrane integration of the protein, resulting in its rapid degradation.

Amino Acid Sequence↗
PubMed1996

The contribution of lysine-36 to catalysis by human myo-inositol monophosphatase.

The role of lysine residues in the catalytic mechanism of myo-inositol monophosphatase (EC 3.1.3.25) was investigated. The enzyme was completely inactivated by amidination with ethyl acetimidate or reductive methylation with formaldehyde and cyanoborohydride. Activity was retained when the active site was protected with Mg2+, Li+, and D,L-myo-inositol 1-phosphate. Using radiolabeling, peptide mapping, and sequence analysis, Lys-36 was shown to be the protected residue, which is responsible for inactivation. Replacing Lys-36 with glutamine produced a mutant protein, K36Q, with similar affinities for the substrate and the activator Mg2+, but a 50-fold lower turnover number as compared to the wild-type enzyme. Crystallographic studies did not indicate any gross structural changes in the mutant as compared to the native form. Initial velocity data were best described by a rapid equilibrium ordered mechanism with two Mg2+ binding before and a third one binding after the substrate. Inhibition by calcium was unaffected by the mutation, but inhibition by lithium was greatly reduced and became noncompetitive. The pH dependence of catalysis and the solvent isotope effect on kcat are altered in the mutant enzyme. D,L-myo-Inositol 1-phosphate, 4-nitrophenyl phosphate, and D-glucose 6-phosphate are cleaved at different rates by the wild-type enzyme, but with similar efficiency by K36Q. All data taken together are consistent with the hypothesis that modifying or replacing the lysine residue in position 36 decreases its polarizing effect on one of the catalytic metal ions and prevents the efficient deprotonation of the metal-bound water nucleophile.

Base Sequence↗
PubMed1996

Growth of human immunodeficiency type 1-infected and uninfected children: a prospective cohort study in Kigali, Rwanda, 1988 to 1993.

OBJECTIVE: To compare the anthropometric characteristics of children with and without HIV-1 infection. METHODS: In a prospective cohort study of 218 children born to HIV-1 seropositive mothers and 218 children born to HIV-1 seronegative mothers in Kigali, Rwanda, 3 groups were compared: infected children (n = 46); uninfected children born to seropositive mothers (n = 140); and uninfected children born to seronegative mothers (n = 207). Weight, height and head circumference were measured at birth, every 3 months during the first year of life and every 6 months thereafter. The weight-for-age, height-for-age, weight-for-height and head circumference-for-age mean z scores were calculated. RESULTS: The weight-for-age, height-for-age and head circumference-for-age mean z scores were lower among HIV-infected children than among uninfected ones at each time period. The reduction in the weight-for-age mean z score was the greatest between 12 and 36 months. The reduction in the height-for-age mean z score of HIV-infected children was persistently below 2 SD after 9 months of age. On the other hand the weight-for-height mean z score was not consistently lower in HIV-infected children when compared with uninfected ones. The anthropometric characteristics of uninfected children born to seropositive mothers were similar to those of children born to seronegative mothers. CONCLUSIONS: In this study HIV-infected children were more frequently stunted (low height-for-age) than uninfected ones. Wasting (low weight-for-height) was not common among HIV-infected children.

Adult↗
PubMed1996

[Management of febrile infants under 3 years old].

Fever is a common symptom in young infants. However, it is often difficult to differentiate young children with severe bacterial infections (SBI) from those with benign febrile illnesses. Clinical, biological and radiological criteria, alone or combined, do not allow to identify with precision young infants with SBI. Simple criteria--including medical history, clinical and hematological evaluation (the "Rochester criteria")--have been proposed by North American clinicians to identify young febrile children at low risk of SBI. These criteria have been validated on large numbers of children in various countries. Their application in different clinical situation is discussed in this article.

Bacterial Infections↗
PubMed1995

Four years of natural history of HIV-1 infection in african women: a prospective cohort study in Kigali (Rwanda), 1988-1993.

Clinical features and mortality due to human immunodeficiency virus type-1 (HIV-1) infection in women are described as part of a prospective 4-year cohort study on perinatal transmission of HIV in Kigali, Rwanda. Two hundred fifteen HIV-seropositive (HIV+) and 216 HIV-seronegative (HIV-) pregnant women were enrolled at delivery between November 1988 and June 1989. Clinical information collected during systematic quarterly examinations was compared. HIV antibody tests were performed at delivery and CD4/CD8 lymphocyte counts at 15 days' postpartum. HIV--women who seroconverted during the follow-up period were excluded from the analysis of the comparison group starting at the date of seroconversion. At enrollment, all HIV+ women were asymptomatic for acquired immune deficiency syndrome (AIDS). Incidence of tuberculosis was 2.9 per 100 women-years (WY) after 4 years of follow-up in HIV+ women versus 0.2 per 100 WY among HIV- women (relative risk, 18.2; 95% confidence interval 2.4-137.0). Among HIV+ women, the incidence of AIDS (World Health Organization clinical AIDS definition) was 3.5 per 100 WY. The mortality rate was 4.4 per 100 WY among HIV+ women versus 0.5 per 100 WY among HIV- women. Clinical AIDS was present in only half of the fatalities. Tuberculosis was a major cause of morbidity and mortality in these HIV+ African women. An early diagnosis and an appropriate treatment or prevention of tuberculosis should improve the quality of life of HIV-infected patients in Africa.

Adult↗
PubMed1995

Activation of a MMTV/mdr3 fusion transcript from a cryptic viral promoter is stimulated by mdr-derived sequences located in intron I.

In P388/VCR-10 cells, resistance to cytotoxic drugs is caused by the overexpression of the mdr3 gene, in absence of gene amplification. The gene is transcriptionally activated following integration of a full-length mouse mammary tumor virus (MMTV) within intron I, upstream of the coding region of the gene. This integration results in the production of MMTV/mdr3 fusion transcripts that originate from the antisense 5'LTR of the provirus. The mechanism of mdr3 activation in these cells remains unclear since it cannot be accounted for either by activation from the normal MMTV promoter or by activation of the mdr3 promoter by MMTV enhancer sequences. Subcloning and sequence analysis of the genomic region encompassing the 5' LTR of the provirus with adjacent mdr3 sequences up to exon 2 showed that the LTR had not undergone small rearrangements or deletions. Transfections of fusion plasmids containing this genomic fragment and the reporter gene luciferase showed the presence of transcriptionally active sequences in that region. Deletions of 5' and 3' sequences from this fragment have shown that the antisense LTR itself has little contribution to the activation of the luciferase gene, whereas the mdr3 derived sequences that include part of intron I and the beginning of exon 2 strongly activated luciferase expression when inserted in either orientations upstream of the reporter gene. These results suggest the presence of an activator element within intron I of mdr3 capable of activating transcription from a cryptic start site present in the antisense MMTV LTR. Derepression of this activator sequence within intron I by a mechanism involving integration of a transposable element may be a prerequisite to transcriptional activation of the gene which is silent in the parental P388 cells. Further support for a derepression mechanism of activation in P388 cells is provided by the identification of independent genomic rearrangements in the 5' region of mdr3 in additional MDR P388 derivatives analyzed in this study.

ATP Binding Cassette Transporter, Subfamily B, Mem↗