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Biomedical subjects

F Forestier

Publications and source records attributed to F Forestier.

At least 109 records · Page 6Linked to original sources
PubMed1988

Early prenatal diagnosis of congenital toxoplasmosis using amniotic fluid samples and tissue culture.

The presence of Toxoplasma gondii in amniotic fluid was demonstrated using tissue culture in four of nine cases of congenital toxoplasmosis, whereas Toxoplasma gondii antigen was undetectable using a sensitive enzyme immunoassay technique. Parasites were identified in monolayers four days after inoculation using an indirect immunofluorescence assay. Since tissue culture may provide evidence of infection within a few days, this method is proposed for early prenatal diagnosis of congenital toxoplasmosis.

Amniotic Fluid↗
PubMed1988

Prenatal diagnosis and management of bleeding disorders with fetal blood sampling.

The technique of fetal blood sampling for prenatal diagnosis has been shown to be both feasible and safe. The availability of fetal blood for direct evaluation has changed our attitude about the problems of both hereditary and acquired immune fetal bleeding disorders. We can continue with the classic approach and use fetal blood sampling for those conditions in which termination may be recommended, but we can also investigate less severe disorders in which the diagnosis allows us to plan the management of the pregnancy and minimize intrapartum and neonatal complications. We report our experience in prenatal diagnosis and management of 103 cases of hereditary and 18 cases of acquired immune bleeding disorders. We have developed specific management plans depending on the disorder under investigation, the severity of the condition in the fetus, and parental wishes. We have performed in utero transfusions of platelets and factor concentrate where appropriate. Efficacy of maternal therapy for fetal conditions can be directly assessed during gestation. Mode of delivery is determined by obstetric conditions and fetal status, directly assessed after appropriate therapy. Closer surveillance of the fetus by fetal blood sampling gives precise information on which to base clinical decisions to provide optimal maternal and fetal outcome.

Bleeding Time↗
PubMed1988

The assessment of fetal blood samples.

Fetal blood sampling under ultrasound control is rapidly expanding the study of human fetal biology. Pure fetal blood is required for prenatal diagnosis, establishment of reference ranges for biologic measurements, and assessment of fetal welfare. We present here the methods that we have developed to detect contamination in more than 1500 samples. These include hematologic indexes, blood smear, erythrocyte antigens, beta-human chorionic gonadotropin, and coagulation factor assays. The tests are relatively simple, inexpensive, and widely available. No single test is reliable in all situations, and it is necessary to perform all the tests on each sample of fetal blood. In the clinical setting where irrevocable action may be taken as a consequence of our results, we require absolute assurance of the purity of the sample.

Blood Cell Count↗
PubMed1988

Physiology and management of intrauterine growth retardation: a biologic approach with fetal blood sampling.

Intrauterine growth retardation is a major contributor to perinatal mortality and morbidity. The most important obstetric problem is to determine which fetuses are well in utero and which are at risk of irreversible damage or severe and prolonged neonatal morbidity. The optimal timing of delivery is at present made by subjective assessment of clinical variables. We present hematologic and biochemical values obtained by fetal blood sampling of 24 idiopathic fetuses with intrauterine growth retardation to give objective information on which to base clinical management. The results show that there is stimulation of erythropoiesis as well as evidence of red blood cell destruction and liver damage. In many cases there is acute decompensation with acid base abnormalities in a setting of chronic hematologic and biochemical changes.

Blood Cell Count↗
PubMed1988

Plasma corticosteroid patterns in the fetus.

In umbilical vein blood samples collected in 137 fetuses between 19 and 31 weeks of gestation, cortisol (F), cortisone (E), 17-hydroxyprogesterone (17-OHP) and 11-deoxycortisol (S) were radioimmunoassayed after column chromatography on Sephadex LH-20 of plasma extracts. While F levels plateaued throughout the period considered those of E displayed an increasing pattern which appeared to be comparable with that of unbound F in pregnant women. The declining pattern of S and more particularly of 17-OHP would suggest an increasing utilization and metabolization of these F precursors by the maturing fetus. E was not correlated with either 17-OHP or S but showed a significant correlation with F. S and 17-OHP were correlated with each other and with F. The significance of these correlations was discussed according to the different origin of these steroids and to their metabolic relationships. The application of this method for the prenatal diagnosis of inborn errors of steroid biogenesis is suggested.

17-alpha-Hydroxyprogesterone↗
PubMed1988

Prenatal and postnatal production of IgM and IgA antibodies to rubella virus studied by antibody capture immunoassay.

Rubella virus-specific IgM and IgA antibodies were quantitated by antibody capture immunoassay in adults after primary infection and after experimentally induced reinfection. Antibodies to rubella virus were also detected in fetuses whose mothers had rubella before week 18 of pregnancy. IgM and IgA concentrations in fetal blood were determined by radial immunodiffusion and enzyme immunoassay, respectively. In primary postnatal infection, IgM antibodies were consistently found until week 8 after onset of the disease, and after week 14 these antibodies were usually no longer detected. The time of disappearance of rubella virus-specific IgA varied with each individual. After vaccination of previously immune volunteers, no change was noted in level of IgA antibody, and no IgM antibody was detected. In infected fetuses, total IgM and IgA concentrations rose significantly, and rubella virus-specific IgM and IgA antibodies were detected as early as week 22 of pregnancy.

Antibodies, Viral↗
PubMed1988

Assessment of fetal blood volume for computer-assisted management of in utero transfusion.

We performed 41 intravascular ultrasound-guided fetal transfusions in a total of 20 pregnancies with erythroblastosis fetalis or alloimmune thrombocytopenia. On the basis of this experience, we developed a computer-assisted procedure for determining the volume to be transfused, which provides an adequate final concentration. Fetal weight was estimated using ultrasound measurements. Fetoplacental blood volume was estimated from the regression line: fetoplacental volume (ml) = 1.046 + fetal weight (g) X 0.14. The volume to be transfused was calculated using the simple dilution formula: Vtransfused = Vfetoplacental.(Cfinal - Cinitial)/Ctransfused where C is the hematocrit or platelet count. The entire procedure is computerized, simple and rapid, and avoids resorting to repeated intermediate sampling. The dilution formula used appears to be more reliable than a formula taking into account the volume added, even in erythroblastosis fetalis where relatively large volumes are injected. This suggests rapid plasma loss during the procedure.

Blood Physiological Phenomena↗
PubMed1988

Management of alloimmune thrombocytopenia: antenatal diagnosis and in utero transfusion of maternal platelets.

Neonatal alloimmune thrombocytopenia (NAIT) can cause severe bleeding in the central nervous system (CNS) and death or severe neurologic sequelae. The expression of the PLA1 antigen is detectable as early as 19 weeks of gestation. Alloimmunization can therefore lead to fetal thrombocytopenia very early in pregnancy. Until recently, we have had no means of detecting and assessing the severity of fetal thrombocytopenia during pregnancy. The level of the maternal antibody is not of a predictable value since 20% of the mothers had no circulating antibodies in our series. An alternative approach is to carry out investigations on fetal blood samplings. This management leads to an exact knowledge of the fetal status and antenatal diagnosis is feasible as early as the 21st week of gestation. Early diagnosis facilitates appropriate management and makes possible such therapeutic options as in utero maternal platelet transfusions. We report our experience in the antenatal diagnosis and management of nine cases with in utero transfusion in the six cases with severe thrombocytopenia. All neonates did well, with no signs of bleeding at birth. No side effects of therapy were noted after a period ranging from 6 months to 3 years.

Antigens, Human Platelet↗
PubMed1988

[Anhydrotic ectodermal dysplasia. Apropos of a case with severe ocular complications].

The anhydrotic ectodermal dysplasia are malformative syndromes involving the ectodermal components of the organism. They may be associated with very varied ocular manifestations. We described one sporadic case of anhydrotic ectodermal dysplasia in a twenty-four year-old man, involving the following ocular manifestations: severe and bilateral keratopathy corneal hypoesthesia involvement of the lacrymal system horizontal nystagmus and a high rate of antilens antibodies not yet reported a far as we know in the literature.

Adult↗
PubMed1987

Measurement of low molecular weight heparin ex vivo activities in clinical laboratories using various anti-Xa assays: interlaboratory variability and requirement for an agreed low molecular weight heparin standard.

The only sensitive and convenient assay to assess the biological activity of low molecular weight heparins (LMWHs) is based on the potentiation of activated factor Xa inhibition. Several procedures for measuring the socalled anti Xa activity have been proposed. In this collaborative study including eight laboratories, we have used four different assays (three amidolytic and one clotting based methods) for measuring the anti Xa activity of ex vivo samples obtained after injecting three different LMWHs. The dispersion of the results obtained by calibration against standard heparin could be reduced by using any of the three LMWHs for calibration. A coefficient of variation less than 0.20 between values obtained in different laboratories using a variety of methods seems acceptable. However it is necessary to refer to a common international standard for expressing the results in units and to define, for each of the three products, the therapeutic range.

Factor Xa↗
PubMed1987

Prenatal diagnosis of hereditary elliptocytosis with molecular defect of spectrin.

Hereditary elliptocytosis (HE) is, in the heterozygous state, a common mild congenital hemolytic disease. In contrast, homozygous elliptocytosis is a severe transfusion-dependent hemolytic anemia. The major determinant of red cell membrane shape and stability is a two-dimensional proteinaceous meshwork named membrane skeleton. Spectrin, the most important protein of the membrane skeleton, is basically a heterodimer composed of alpha and beta chains. Within the membrane, spectrin dimers self-associate to form tetramers. In type I HE spectrin dimer self-association is defective and an excess of spectrin dimer is present in the patient's red cell membranes. The defective self-association is often correlated with an abnormality of the spectrin alpha chain which is depicted by limited tryptic digest of spectrin. In a family previously studied by us (Dhermy et al., 1984), the search for a spectrin defect in the red cells of the fetus of the pregnant mother was indicated for the following reasons: the diagnosis of heterozygous type I HE with the same spectrin variant had been made in the mother as well as in the father. Moreover, homozygous HE had been recognized in one of the children born two years previously with a persistent and severe transfusion dependent hemolytic anemia. Preliminary studies of normal fetal erythrocytes at twenty weeks gestation have shown that fetal and adult spectrin molecules are identical. The results obtained in the fetus at risk allowed us to diagnose type I HE (though elliptocytes were not present in the blood) for the following reasons: (i) erythrocyte deformability was decreased (ii) spectrin self-association was defective with an excess of dimer species in the membrane (iii) limited tryptic digest of spectrin showed the same abnormal pattern as seen in the heterozygous mother, with a decrease in the 80,000-dalton peptide and a concomitant increase in the 74,000-dalton peptide. The heterozygous state, strongly suspected on the tryptic digest pattern of fetal spectrin, was confirmed when the mother gave birth to a baby who did not have hemolytic anemia during the first 18 months of life.

Elliptocytosis, Hereditary↗