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P Blot

Publications and source records attributed to P Blot.

At least 19 recordsLinked to original sources
PubMed1992

Vitamin B12 among parturients and their newborns and its relationship with birthweight.

Vitamin B12 (Cobalamin) is an essential nutrient in the diet of humans, particularly during pregnancy, nevertheless very few epidemiological studies have been reported, particularly concerning variation factors. The purpose of this study is to assess the role of vitamin B12 on birthweight after taking into account potential confounders, such as obstetrical, socioeconomic, and biological factors which will be identified. This study was conducted on 188 single births occurring during a 5-month period in an obstetrical care unit in Paris. Vitamin B12 plasma levels and folate plasma levels of mothers and cords along with haematological parameters were measured. Social and obstetrical features of the mothers as well as their tobacco exposure and alcohol consumption were recorded. Cord blood vitamin B12 levels were highly correlated with maternal levels (r = 0.63, P less than 0.001) and were 2-3-fold higher. Three variation factors of vitamin B12 were identified: maternal age, ethnicity and tobacco exposure. Negative correlations between birthweight and vitamin B12 levels were observed only among the smoker group (r mothers = -0.46, P less than 0.05 and r cords = -0.42, P less than 0.05). After adjustment for ethnicity and parity, birthweight remained negatively linked to vitamin B12 in smokers. This relationship could suggest that the availability of vitamin B12 for fetal development depends on certain biological factors present only in mothers who smoked. We hypothesized this relationship could be explained, in part, by lipid metabolism, particular to smokers.

Adult↗
PubMed1992

Placental aryl hydrocarbon hydroxylase activity and placental calcifications.

Induction of aryl hydrocarbon hydroxylase (AHH) activity in the placenta as a result of maternal exposure to polycyclic aromatic hydrocarbons contained in cigarette smoke has been well documented. Furthermore, calcifications are more prevalent in the placentas of pregnant smokers than in those of non-smokers. The present study examines whether this latter relationship could be explained by the induction of AHH activity in the placenta. AHH levels were determined at birth in 141 unselected pregnant women admitted for delivery. Macroscopic placental examination was performed for vascular lesions, abnormalities of placental shape, of the cord and parameters of placental maturity such as basal and parenchymatous calcifications. Significant increases in the prevalence of calcifications of the placental basal plates and parenchyma with the induction of placental AHH were found. A similar significant association between smoking and AHH activation was also observed. These findings remained unchanged when controlling for smoking status assessed both by questionnaire and presence of cotinine in mother's urine. Moreover, the apparent association between smoking 'factor' and calcifications disappeared when controlling for AHH induction. Therefore, the association between smoking and placental calcifications previously related could be mediated by the AHH induction.

Aryl Hydrocarbon Hydroxylases↗
PubMed1992

Clinical and pharmacologic study of fetal supraventricular tachyarrhythmias.

The purpose of this study was to evaluate the efficacy of maternal digoxin administration in 16 cases of fetal supraventricular tachyarrhythmia diagnosed by fetal echocardiography; cardiac anatomy was normal in all cases. The retrospective analysis included nine mothers who received digoxin orally in most cases, with control of the arrhythmia in two fetuses. The addition of amiodarone (five cases) and propranolol (two cases) yielded two successes with amiodarone. The therapeutic regimen of digoxin was then modified on the basis of poor response to orally administered digoxin. In the prospective study, digoxin was administered intravenously to seven mothers according to a standard protocol; high doses (1 to 2 mg intravenously) were prescribed for the first 24 hours and intravenous digoxin therapy was maintained for at least 5 days, depending on the fetal response. Digoxin pharmacokinetic studies of four mothers showed an increased plasma clearance and reduced elimination half-life. Digoxin controlled the five supraventricular tachycardias (with hydrops in four cases). Maternal flecainide therapy restored sinus rhythm in two cases of atrial flutter. Our prospective study emphasizes the efficacy and safety for the fetus and the mother of intravenously administered digoxin as a first-choice drug in the treatment of supraventricular tachyarrhythmias. Flecainide may be a promising second-choice drug but requires further clinical investigation. Amiodarone and propranolol seem to be ineffective.

Digoxin↗
PubMed1992

Mother-to-infant vertical transmission and cross-colonization of Streptococcus pyogenes confirmed by DNA restriction fragment length polymorphism analysis.

Restriction fragment length polymorphism (RFLP) analysis of total DNA and of ribosomal DNA (rDNA) regions (ribotyping) were used to document Streptococcus pyogenes vertical mother-to-infant transmission and to investigate the spread of S. pyogenes in an obstetric unit. Two isolates from a newborn, two isolates from his mother (patient 1), and two isolates from two other mothers (patients 2 and 3) were studied. RFLP of total DNA, both after HindIII and PvuII digestions and ethidium bromide staining, gave indistinguishable patterns for the strains isolated from the neonate, his mother, and patient 2. Strains from patient 3 and six unrelated strains studied for comparison showed different patterns. In our system, ribotyping was less discriminative than total DNA RFLP analysis. DNA RFLP analysis therefore provides a valuable molecular tool for studying S. pyogenes epidemiology.

Adult↗
PubMed1992

The Wolf-Hirschhorn syndrome in fetuses.

Wolf-Hirschhorn syndrome (WHS) with partial deletion of the short arm of chromosome 4 has been exceptionally diagnosed in fetuses. We report prenatal diagnosis of five cases of monosomy 4p. The fetuses were karyotyped for severe intrauterine growth retardation (IUGR) diagnosed on routine ultrasound (US). In addition, cleft-lip and palate and diaphragmatic hernia respectively were found in two cases. The quantity of amniotic fluid was normal in all cases. At autopsy, the fetuses showed the typical craniofacial dysmorphy but without microcephaly. Major renal hypoplasia was the only constant visceral anomaly. Midline fusion defects were observed in all the fetuses, ranging from minor abnormalities such as scalp defect, hypertelorism, pulmonary isomerism, common mesentery, hypospadias and sacral dimple, to cleft palate, corpus callosum agenesis, ventricular septal defect, and diaphragmatic hernia. On post-mortem X-rays, a delayed bone age was always observed. All the placentae were hypotrophic, and two exhibited vascular lesions, although there was no maternal hypertension. Chromosomal studies showed that the breakpoints were within the 4p16 band in three cases, the 4p15 band in one case, and the 4p14 band in one case. The deletion was de novo in four cases, and resulted from a paternal translocation in one case. This study emphasizes the importance of karyotyping all fetuses with IUGR, especially when the quantity of amniotic fluid is normal, and suggests the possibility of recognizing on US the particular phenotype of WHS in utero.

Abnormalities, Multiple↗
PubMed1992

Comparison of T cell functional changes during childhood with the ontogeny of CDw29 and CD45RA expression on CD4+ T cells.

The ontogeny of the peripheral blood mononuclear cells' responsiveness to various activators during childhood was studied and compared to the expression of CDw29 and CD45RA molecules at the surface of CD4+ T cells. The results show that newborn peripheral blood mononuclear cells are characterized by a responsiveness to mitogens that is higher than that observed in adults, at least shortly after stimulation. This contrasts with a clear decreased response to CD2 and CD3 MAb at any time after stimulation. These functional characteristics correlate with a low density of CDw29 antigen on virtually all CD4+ T cells and a high density of CD45RA antigen on most CD4+ T cells at birth. These patterns of reactivity and phenotype are similar to those found among naive adult T cells. When ageing, the response to mitogens becomes rapidly similar to the adult's values, whereas the responses to CD2 or CD3 MAb are more gradually acquired. This slow rate of functional changes grossly parallels the increase of CDw29+ CD4+ and the decrease of CD45RA+ CD4+ T cell subsets. These changes finally lead to the immunophenotypic and functional characteristics that are typical of adult memory T cells. These results suggest that iterative antigenic stimulations both induce memory T cells and create the conditions to improve the overall immune competence.

Adolescent↗
PubMed1991

Unusual evolution of a pericardial mass diagnosed by fetal echocardiography.

An intrapericardial mass with a pericardial effusion was diagnosed by ultrasound examination in the fetus of a 29-year-old gravida 1 para 0 woman at 32 weeks' gestation. Serial in utero examinations showed disappearance of the pericardial effusion at 35.5 weeks' gestation, while the mass remained unchanged. Vaginal delivery ensued at 39 weeks. Clinical and echocardiographic examination of the newborn revealed normal cardiac anatomy with no abnormal mass or pericardial effusion. Follow-up examinations confirmed these normal data.

Adult↗
PubMed1990

Placental transfer of tetanus antibodies and protection of the newborn.

The aim of the study was to compare the placental transfer of tetanus toxoid antibodies (TTAB) and total IgG in Africa, where we had previously demonstrated a lack of transmission from mother to the newborn of measles antibodies. Two series of mother-child pairs, 45 in Paris and 134 in Libreville, Gabon, Central Africa, were measured after full-term pregnancies and normal deliveries. Means of ratios of cord/mother concentrations for TT AB and IgG were, respectively, 2.52 and 1.28 in Paris and 0.98 and 0.82 in Gabon. In 11 pairs from Libreville no TT AB were found in mother and cord blood, but in four other African newborns (3 per cent), the mother transmitted TT AB which were lower than protective level against tetanus. Other data (negative correlation between mother IgG and cord/mother ratio of corresponding TT AB concentrations, and better transmission of TT AB in the low range of maternal IgG) indicate that the limitation of active placental transfer of antibodies is related to the high maternal IgG level common in Africa.

Adolescent↗
PubMed1990

[Placental transfer of tetanus antibodies and protection of newborn infants].

Total IgG and tetanus antibodies were evaluated in 2 series of mother-child pairs: 50 in Paris and 134 in Africa. All pregnancies had been normal and birth weights greater than 3 kg. Cord blood mothers tetanus antibodies ratios were 1.5 in Paris and 0.98 in Libreville (p less than 0.01) respectively. Some African children were not protected, either due to the lack of response of their mothers to immunization (2.2%) or to an insufficient antibodies transplacental transport (2.9%), or to the lack of immunization of mothers (5.9%). On the contrary, all European children were protected, in spite of low maternal antibody levels. Likewise, in Paris cord blood IgG level was 12.24 g/l vs 9.42 in mothers (cord blood/mother ratio: 1.34) and in Africa 18.4 g/l in cord blood and 22.3 g/l in mothers (cord blood/mother ratio: 0.88; p less than 0.01). The correlations between maternal IgG levels and placental transfer rates indicate that the transplacental active transfer is limited by common high IgG levels in Africa, thus contributing to a decrease in protection of neonates, especially against tetanus in which humoral responses predominate.

Adolescent↗