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Biomedical subjects

B Leroux

Publications and source records attributed to B Leroux.

At least 37 records · Page 2Linked to original sources
PubMed1998

Prenatal diagnosis of congenital toxoplasmosis transmitted by an immunocompetent woman infected before conception. Reims Toxoplasmosis Group.

We report a rare case of congenital toxoplasmosis transmitted by an immunocompetent woman infected before conception. Active toxoplasmosis was suspected due to persistent lymphadenitis with specific IgM, IgA, IgE antibodies. Prenatal diagnosis based on amniocentesis and fetal blood sampling at 24 weeks' amenorrhoea was positive on amniotic fluid, and fetal infection was confirmed after termination. In our opinion such cases need the same monitoring as when seroconversion occurs during the first trimester. A pregnancy-free interval of six to nine months is recommended after proven patent toxoplasmosis seroconversion.

Adult↗
PubMed1997

Prenatal diagnosis of congenital toxoplasmosis in 261 pregnancies.

Two hundred and sixty-one pregnant women underwent prenatal screening by cordocentesis and/or amniocentesis between 1987 and 1994. The following tests were used: (i) detection of anti-Toxoplasma gondii IgM, IgA, and IgE antibodies by immunocapture and the comparative immunological profile method based on enzyme-linked immunofiltration assay of fetal blood and (ii) direct detection of the parasite in cell culture and by mouse inoculation with fetal blood (FB) and/or amniotic fluid (AF). Of the 31 cases of congenital toxoplasmosis, 24 (77 per cent) were detected prenatally. Overall, the FB and AF inoculation methods were the most effective (50 per cent sensitivity with FB inoculation to mice and/or cell culture and 74 per cent with AF). However, antibody detection in FB was the only positive test in three cases. Of 18 surviving children diagnosed prenatally, only one developed chorioretinitis (9 months of age). Seven newborns (23 per cent) with negative prenatal tests were diagnosed by postnatal laboratory monitoring, but none of these children developed clinical toxoplasmosis. There may have been more false negatives, as only 48 per cent of unaffected children were followed up for at least 12 months. All the tests had a specificity of 100 per cent. Fetal blood sampling has considerable value but also carries some risks and is currently being abandoned in favour of amniocentesis alone with gene amplification and mouse inoculation.

Amniocentesis↗
PubMed1997

Pharmacokinetics of oral triazolam in children.

The purpose of this study was to determine the pharmacokinetic behavior of triazolam in children. Nine healthy children, aged 6 to 9 years, received oral triazolam (0.025 mg/kg suspended in Kool-Aid, Kraft General Foods, Chicago, IL) before dental treatment. Plasma triazolam concentrations were measured by gas chromatography/mass spectrophotometry at approximately 5, 15, 30, 45, 60, 90, 120, 180, and 240 minutes. A one-compartment model with first-order absorption and varying parameters was used, and estimated concentration curves were obtained for each subject. The observed peak plasma concentration was 8.5 +/- 3.0 ng/mL (mean +/- SD). The observed time to peak plasma concentration was 74 +/- 25 minutes. Elimination half-life was 213 +/- 144 minutes. Substantial recovery from signs and symptoms of clinical sedation required 180 to 240 minutes. The long duration of effect and relatively slow elimination should be noted by clinicians concerned with patient safety.

Biological Availability↗
PubMed1997

Pain control in recovering alcoholics: effects of local anesthesia.

OBJECTIVE: The medical literature suggests that alcoholics may present greater challenges to achieving clinical pain control than nonalcoholics. This study was undertaken to test the hypotheses that: (1) significant differences exist between alcoholics and nonalcoholics on detection and pain thresholds during electric tooth stimulation; (2) group differences exist in the depth and time course of pulpal anesthesia; and (3) responses to tooth stimulation are associated with severity of alcoholism and/or other psychological factors. METHOD: Male alcoholics (n = 22) in aftercare treatment (mean length of sobriety = 113 days) and age-matched nonalcoholics (n = 22) received 1.0 ml of 3% mepivicaine at the apex of a maxillary lateral incisor and saline placebo at the apex of the contralateral incisor. RESULTS: At baseline no group differences were found on sensory thresholds. During drug intervention significant drug and time effects for both detection threshold (p < .0001) and pain threshold (p < .0001) were found, but group differences and interactive effects were not significant. By exploratory regression analysis of alcoholic subjects, history of depression/unhappiness was significantly associated with shallower pulpal anesthesia, whereas high need for control/low actual control and frequency of treatment for detoxification were associated with deeper anesthesia. CONCLUSIONS: Our findings suggest alcoholics in recovery are not at increased risk for inadequate pain control with local anesthesia.

Adult↗
PubMed1997

[Screening for congenital toxoplasmosis: pregnancy outcome after prenatal diagnosis in 211 cases].

OBJECTIVE: To emphasize the importance of follow-up after birth of infants with an antenatal diagnosis of congenital toxoplasmosis. METHODS: Retrospective study from July 1987 through January 31 1995 on 211 women (214 fetuses) who had undergone ovular biopsy for toxoplasmosis seroconversion during pregnancy. RESULTS: Antenatal diagnosis was positive in 13 patients (6.2%). Four pregnancies were terminated during the second trimester. Delivery was triggered at 37 weeks gestation in one woman and in 8 others pregnancy was continued with Fansidar. All infants were born live with infraclinic disease. Two fetal deaths related to biopsy technique occurred (0.95%) and one pregnancy was terminated before the results had been obtained. Only 21.3% of the patients were delivered in our unit. A total of 197 infants were delivered with a negative antenatal diagnosis: 93 were healthy, 5 had congenital toxoplasmosis, 1 died at 3 months and 98 had no or incomplete follow-up. CONCLUSION: Incomplete post-natal follow-up is in contradiction with the excellent performance of antenatal diagnosis of congenital toxoplasmosis. Greater care is needed, especially since now only an amniocentisis is required to detect the parasite genome with polymerase chain reaction.

Adolescent↗
PubMed1996

Early neonatal diagnosis of congenital toxoplasmosis: value of comparative enzyme-linked immunofiltration assay immunological profiles and anti-Toxoplasma gondii immunoglobulin M (IgM) or IgA immunocapture and implications for postnatal therapeutic strategies.

Diagnostic strategies for congenital toxoplasmosis have changed profoundly in recent years. Immunological diagnostic methods, long considered disappointing, can now be used at a very early stage. Over a 3-year period, 1,050 infants at risk of congenital toxoplasmosis (born to 1,048 mothers infected during pregnancy) were monitored for a minimum of 12 months and a maximum of 7 years. More than 6,000 serum specimens were analyzed by comparative mother-infant immunological profiles (CIPs) based on an enzyme-linked immunofiltration assay (ELIFA) and an immunocapture method for the detection of specific immunoglobulin M (IgM) and IgA. IgG antibodies were also titrated. One hundred three cases of congenital toxoplasmosis were demonstrated. The CIP-ELIFA method had a better diagnostic yield (sensitivity, 90%) than specific IgM and/or IgA detection by immunocapture assay (sensitivity, 77%). By using a combination of these tests, congenital infection was diagnosed in the first month and the first 3 months of life in 90 and 94% of infants with toxoplasmosis, respectively, with a specificity of 99.8% and a positive predictive value of 99% at 8 months of age. This dual diagnostic approach (ELIFA and IgM-IgA immunocapture) is highly efficient and has important implications for therapy. Indeed, early postnatal diagnosis based on objective evidence enables therapy with pyrimethamine-sulfadoxine to be started immediately for 24 months, while spiramycin (which used to be given preventively for 9 to 12 months to all infants at risk) can be stopped after the first 3 months of life.

Animals↗
PubMed1995

[Tuberculosis and pregnancy].

The authors report a case of pulmonary tuberculosis during pregnancy. They point out that the pregnancy does not change the natural course of the disease, congenital tuberculosis is rare but with a high rate of mortality, and the three most important antituberculosis (isoniazid, ethambutol and rifampicin) are safety during pregnancy.

Adult↗
PubMed1992

Gastroschisis: what part can the obstetrician play?

In order to assess the contribution of antenatal diagnosis to the management of gastroschisis, the antenatal and postnatal data from 24 cases of gastroschisis observed between 1974 and 1990 were re-examined. The frequency of antenatal diagnosis (29%), polyhydramnios (21%), atresia of the small intestine (29%), length of pregnancy (36.6 +/- 2 weeks of amenorrhea), proportion of cesarean sections (21%), birth weight (2230 +/- 430 g) and the Apgar score after 5 min (9.0 +/- 1.5) were comparable to findings reported elsewhere. The overall mortality rate for the period studied was high (41%), and was not influenced by any antenatal parameter or by the mode of delivery; its recent fall (P = 0.01) is explained by the development of therapeutic methods. These results are consistent with other recent studies and suggest that antenatal diagnosis does not enable an accurate assessment of the prognosis to be made and has no major influence on the mortality rate in gastroschisis.

Abdominal Muscles↗
PubMed1992

Effects of brief early exposure to partially hydrolyzed and whole cow milk proteins.

Clinical experience ("the dangerous bottle") and experimental evidence indicate that the early life of an infant is particularly important for the development of the immune responses to food antigens. However, the clinical and immunologic consequences of a brief exposure to, or avoidance of, food antigens during the neonatal period in human infants are poorly understood and documented. We present the preliminary results of a prospective controlled study of 256 normal breast-fed infants randomly assigned to receive (blind) either an adapted formula (Nidina) or a partially hydrolyzed formula (Nidal HA) as a supplement to breast-feeding for a few days when necessary, and to be examined at days 5, 90, 150, and 365. The results indicated that (1) the prevalence of clinical symptoms and of total and specific IgE responses was not statistically different in the two groups of infants and (2) infants fed a hydrolyzed formula had median titers of specific IgG lower than those fed an adapted formula; the difference was significant for alpha-lactalbumin at day 90 (p < 0.005) and for alpha-lactalbumin (p < 0.05), casein (p < 0.05), and hydrolyzed formula (p < 0.01) at day 150. Humoral immune responses of breast-fed infants to food antigens thus appear to be modulated by early, short-term exposure to them.

Breast Feeding↗
PubMed1992

[The risks of pyrimethamine-sulfadoxine combination in the prenatal treatment of toxoplasmosis].

Some of the alternative treatments to avoid termination of pregnancy in cases where the fetus is affected by toxoplasmosis is to treat it as soon as the diagnosis has been made. The authors who already have experience of using pyrimethamine with sulfadoxoine (Fansidar) in the post-natal treatment of congenital infection, thought after reviewing the literature that this association of drugs would be harmless if applied during pregnancy. The principal risk that arises in the fetus is the teratogenicity of each of the components of pyrimethamine and sulfadoxine and also their associations. In animals pyrimethamine can increase the frequency of cleft palates probably because of its antifolinic action but there is no formal proof that it is teratogenic in human beings. Furthermore, the theoretical risk of karnicerus in the new born using the Sulfonamide has not been demonstrated. In the mother the main but rare risk (1 in 75,000) seems to be for the production of severe skin lesions such as Lyell and Stevens-Johnson which could be brought about by sulfonamides, but not particularly sulfadoxine.

Antimalarials↗
PubMed1991

Regulation of the maize rab17 gene promoter in transgenic heterologous systems.

The maize rab17 gene is expressed in different plant parts in response to ABA and osmotic stress (J. Vilardell et al., Plant Mol Biol 14 (1990) 423-432). Here we demonstrate that 5' upstream sequences of the rab17 gene confer the appropriate patterns of expression on the chloramphenicol acetyl transferase (CAT) reporter gene in transgenic tobacco plants, as well as in protoplasts derived from cultured rice cells. Specifically, a CAT construct containing a large 5' upstream fragment of rab17 (-1330/+29) results in high levels of CAT activity in embryos, leaves and roots of transgenic plants subjected to water stress or ABA treatment. Transient expression assays in rice protoplasts transfected with CAT genes fused to rab17 promoter deletions indicate that a 300 bp DNA fragment (-351/-102) is sufficient to confer ABA responsiveness upon the reporter gene. Furthermore, a 100 bp sequence (-219/-102) is capable of conferring ABA responsiveness upon a minimal promoter derived from the 35S CaMV promoter. Gel retardation experiments indicate that maize nuclear proteins bind to this fragment. This region of 100 bp contains a sequence (ACGTGGC) which has been identified as an abscisic acid response element in studies of other ABA-responsive plant genes.

Cell Nucleus↗
PubMed1990

[Should immunologic monitoring of toxoplasmosis seronegative pregnant women stop at delivery?].

The authors report 2 cases of congenital toxoplasmosis fortuitously diagnosed in 2 newborn infants aged 12 and 35 days respectively whose mothers had no anti-Toxoplasma antibodies detectable at the time of birth. These cases prompted us to carry out, over an 18 months' period, a systematic postnatal control of all pregnant women who were still seronegative at the time of delivery. This enabled us to detect 4 cases of perinatal maternal infection with Toxoplasma contamination in 2 neonates. In view of these results, and in order not to miss any maternal infection at the very end of pregnancy, it seems advisable to complete the control of seronegative women by taking a last blood sample about 30 days after they have given birth.

Adult↗
PubMed1989

Isotypic characterization of anti-Toxoplasma gondii antibodies in 18 cases of congenital toxoplasmic chorioretinitis.

A serological study was carried out by ELIFA (Enzyme Linked Immuno-Filtration Assay) for 50 children with congenital toxoplasmosis diagnosed by several parasitological and serological methods showing that the fetus had been infected by the parasite and had developed it's own specific immune response. At birth, anti-Toxoplasma gondii IgE antibodies were detected in the sera of 66% of the 18 children who had retinochoroiditis and in 32% of the 32 children without this complication. During the 4 months before or at the time of diagnosis of retinochoroiditis, specific IgE antibodies were detected in 70% of the 20 cases (2 children with 2 successive lesions); but during the 4 months following the discovery of ocular lesions, anti-Toxoplasma IgE antibodies were only detected in 30% of the 20 cases. Among all the 50 children, the prolonged detection of specific IgM + IgE association (for at least 4 months) was followed in 46% of cases by the appearance of chorioretinitis (predictive value).

Animals↗
PubMed1987

[Early diagnosis and surveillance of congenital toxoplasmosis. The comparative immunological profiles method].

More than 8000 samples (sera, cord blood, CSF, etc.) from patients who had, or were likely to have, toxoplasmosis were studied by the CIP-ELIFA technique. The first stage in this technique is immunoelectrodiffusion on a microporous cellulose acetate membrane. In the second stage, immunodetection and isotypic characterization of the precipitating systems are rapidly carried out by immunofiltration with anti-IgG, IgM, IgA or IgE-labelled antibodies (enzyme-linked immunofiltration assay or ELIFA). Several samples are jointly laid out on the same membrane for compared immunological profiles (CIP). When applied to the mother-foetus relationship in toxoplasmosis, this procedure provides an early diagnosis of congenital infestation in 85% of the cases. Positive criteria are based on evidence of specific IgM, IgE or IgA in the child, but also on the detection of foetal or neonatal antitoxoplasmosis IgG which can be distinguished from the IgG transmitted by the mother. Polyisotypic supervision is of considerable value for assessment of prognosis and of therapeutic effectiveness at the end of treatment. Satisfactory isotypic characterization can only be achieved by using particular functional antigens.

Antibodies↗
PubMed1987

Characterization of the virA locus of Agrobacterium tumefaciens: a transcriptional regulator and host range determinant.

The virulence (vir) region of Agrobacterium tumefaciens mediates the transfer of a defined segment of plasmid DNA (the T-DNA) into the plant genome. The vir genes are specifically induced by molecules produced by wounded plant cells, and virA is required for this induction. We have determined the nucleotide sequence of virA loci from limited (pTiAg162) and wide (pTiA6) host range tumor-inducing (Ti) plasmids, each of which encodes a single protein of 92,000 daltons. Using antibody directed against the virA gene product, we have localized the VirA protein to the bacterial inner membrane. VirA is homologous to at least four bacterial proteins which play a role in the transcriptional regulation of diverse families of genes. Based on its role in vir gene induction, homology to transcriptional regulators and membrane localization, we propose that VirA acts as an environmental sensor of plant-derived inducer molecules and transmits this information to the level of vir gene expression. The pTiAg162 virA locus was shown to be ineffective at directing vir gene induction, suggesting that this may in part contribute to the narrow host range conferred by this plasmid.

Bacterial Proteins↗
PubMed1987

Processing of the T-DNA of Agrobacterium tumefaciens generates border nicks and linear, single-stranded T-DNA.

Transfer and integration of a defined region (T-DNA) of the tumor-inducing (Ti) plasmid of Agrobacterium tumefaciens is essential for tumor formation. We used a physical assay to study structural changes induced in Agrobacterium T-DNA by cocultivation with plant cells. We show that nicks are introduced at unique, identical locations in each of the 24-base-pair imperfect direct repeats which flank the T-DNA and present evidence that a linear, single-stranded molecule is generated. We propose that these changes result from processing of the T-DNA for transfer and that they occur by a mechanism similar to DNA processing during conjugative DNA transfer between bacteria.

Cell Line↗
PubMed1985

[Laurence-Moon-Bardet-Biedl syndrome, chronic diffuse tubulo-interstitial nephritis and liver involvement].

The authors report the case of a 6-year-old girl with Laurence-Moon-Bardet-Biedl syndrome and chronic tubulo-interstitial nephritis with glomerulosclerosis requiring chronic peritoneal dialysis, then haemodialysis. One year later, minimal hepatic involvement occurs, leading to portal hypertension. The liver biopsy reveals periportal fibrosis with many small bile ducts.

Bile Ducts, Intrahepatic↗