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Biomedical subjects

J C Nicolas

Publications and source records attributed to J C Nicolas.

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

[Bronchiolitis caused by respiratory syncytial virus in very young infants and transmitted maternal antibodies].

The study with an Enzyme Linked Immunosorbent Assay of the sera of 57 infants aged less than 9 weeks and developing a bronchiolitis, argues for the absence of a protective role for the maternally transmitted anti-respiratory syncytial virus (RSV) IgG and for the existence of a positive relationship between these antibodies levels - which are not neutralizing - and the severity of RSV bronchiolitis.

Antibodies, Viral↗
PubMed1987

Bioluminescent enzyme immunoassay for progesterone using monoclonal antibodies and glucose-6-phosphate dehydrogenase labels.

Bacterial luciferase, NAD(P): FMN oxidoreductase and anti-mouse immunoglobulin were co-immobilized on Sepharose 4B. This reagent together with a progesterone glucose-6-phosphate dehydrogenase conjugate and various anti-progesterone monoclonal antibodies was used to develop a non-separation bioluminescent immunoassay for progesterone. This monoclonal antibody based assay was sensitive and reliable and using the tracer progesterone-11-acetate-glucose-6-phosphate dehydrogenase, the majority of the monoclonal antibodies give a better sensitivity with this enzymatic tracer than that obtained with an iodinated tracer. In a second assay design progesterone-glutathione was co-immobilized with bacterial luciferase and NAD(P): FMN oxidoreductase on Sepharose 4B and three monoclonal antibodies were labelled with glucose-6-phosphate dehydrogenase. With aqueous progesterone standards, this assay gave comparable sensitivity to the bioluminescent enzyme immunoassay using the second antibody immunoadsorbent and to an RIA but was unsuitable for plasma samples.

Antibodies, Monoclonal↗
PubMed1987

Bioluminescence: an improvement in the enzymatic assay of dehydroepiandrosterone sulfate in biological fluids.

Dehydroepiandrosterone sulfate (DHEAS) determination in biological fluids was carried out by enzymatic hydrolysis and conversion into estrogens [estrone (E1) and estradiol (E2)] by the multienzyme system of human placental microsomes. The enzymatic complex consists of sulfatase, 3 beta-hydroxysteroid oxido reductase and 5en----4en isomerase which converts DHEAS into androstenedione (A); the latter component is further converted into estrogens by the aromatase. The resulting estrogens were determined from the NADH formed by the transhydrogenation reactions of human placental dehydrogenase. NADH was measured by bioluminescence. As little as 4 pg was assayable by this rapid enzymatic method, with a coefficient of variation of 8%. The results are in good agreement with radioimmunoassay and the method is suitable for routine use.

Dehydroepiandrosterone↗
PubMed1987

Evaluation of three assays on alveolar lavage fluid in the diagnosis of cytomegalovirus pneumonitis after bone marrow transplantation.

Cytologic examination, immunofluorescence assays, and cultures for virus were compared prospectively in the detection of cytomegalovirus (CMV) in cells obtained by 41 bronchoalveolar lavages (BALs) from 30 bone marrow transplant recipients with pneumonia. No evidence of CMV was found in 21 BALs. Viral inclusions, positive immunologic assays, and positive cultures were found in 14, 15, and 18 BALs, respectively. Cytological and immunologic results were closely related except in one BAL. In five BALs, a positive culture for virus was the sole criterion noted for diagnosis of CMV. The patients with both cytologically and immunologically positive results were more likely to die with or from respiratory failure (P less than .05), diffuse interstitial patterns (P less than .01), and severe acute graft-vs.-host disease (P less than .02) than were the patients without any criterion for diagnosis of CMV. The discrepancies with the previously reported data, the interpretation of the three diagnostic procedures, and the ability of BAL to diagnose CMV pneumonia are discussed.

Adolescent↗
PubMed1987

Mapping of the gene coding for Epstein-Barr virus-determined nuclear antigen EBNA3 and its transient overexpression in a human cell line by using an adenovirus expression vector.

The open reading frame which lies within the Epstein-Barr virus (EBV) T2 cDNA isolated by Bodescot et al. (M. Bodescot, O. Brison, and M. Perricaudet, Nucleic Acids Res. 14:2611-2620, 1986) was inserted into a eucaryotic expression vector containing a strong adenovirus promoter. The T2 cDNA contains viral genomic sequences from the short BLRF3 open reading frame fused to the adjacent BERF1 long open reading frame. After transfection of human cells, the recombinant plasmid directed the expression of a 140-kilodalton protein. The expressed protein had the same molecular weight, subcellular localization, and immunological characteristics as the EBV-determined nuclear antigen EBNA3, which is made in lymphocytes latently infected with EBV. Immunoprecipitation of extracts of transfected cells labeled with [32P]phosphoric acid showed that the EBNA3 protein is phosphorylated.

Adenoviruses, Human↗
PubMed1986

Antibody response to the rubella virus structural proteins in infants with the congenital rubella syndrome.

Forty-five serum samples from 31 newborns and infants with the congenital rubella syndrome (CRS) were tested by immunoprecipitation to determine their antibody spectra to each of the structural proteins of rubella virus. Most sera (37/45) contained little or no E2 protein-specific antibody, but some (6/45) precipitated a greater amount of the E2 glycoprotein than the E1 glycoprotein. The relative E1/E2 ratio was found to decrease with time when serial serum samples from the same patient were tested. No correlation between the IgG class hemagglutination inhibition antibody titers and the E1/E2 ratio could be demonstrated. However, in some serum specimens relatively high neutralizing antibody titers were correlated with immunoprecipitation of the E2 glycopolypeptide. None of the CRS sera reacted well with the C protein. The immunoprecipitation patterns found in CRS sera were qualitatively different from those observed in a series of 25 sera from young adults with conventional serologic evidence of rubella immunity following natural infection. All of the natural immune sera recognized each of the three structural polypeptides of rubella virus.

Age Factors↗
PubMed1986

Epidemiologic and genomic study of rotavirus strains infecting young children and calves in the same rural environment.

The epidemiological profile of rotavirus infection in young calves and young children form the same rural environment in France was studied during autumn-winter 1983-1984. Viruses were isolated from calves on each farm and were identified by their electropherotype for 8 out of the 9 farms under study. Among 13 children regularly checked on 9 farms for 25 weeks, 7 were found to be rotavirus positive. Nevertheless, no transfer of virus between child and bovine was documented by the electropherotype migration. In the case of the calves, the predominance of the Ib IIa IIIe IVa electropherotype at 5 of the 9 farms is similar to the epidemiological situation observed among newborn in some maternity wards.

Animals↗
PubMed1986

Effect of steroid hormones on the regulation of uterine contractility.

The kinetics of myosin light chain (LC20) phosphorylation has been studied during in vitro contraction and relaxation of rat uteri. Phosphorylation preceded contraction and continued during tetanus induced by KCl; the degree of phosphorylation was proportional to the percentage of contraction. On the other hand, during relaxation induced by isoproterenol, the level of phosphorylation did not change in the seconds following relaxation. A rapid change in cAMP did not appear to trigger a rapid change in LC20 phosphorylation. In cyclic rats, progesterone decreased the extent of LC20 phosphorylation: 50%-60% of the LC20 was phosphorylated in untreated animals or estrogen treated animals. This value fell to 30% after progesterone treatment of cyclic rats. In ovariectomized rats, steroid hormones did not affect the phosphorylation reaction. Under the same conditions, the level of cAMP-dependent protein kinases did not change during the cycle, or after estradiol-treatment, but in cyclic rats it doubled after progesterone treatment. Hence, the decrease in the level of LC20 phosphorylation observed in cyclic rats treated by progesterone could be due to a decrease in myosin light chain kinase (MLCK) activity, resulting from a higher proportion of the phosphorylated form of this enzyme. The concomitant increase in the proportion of activatable cAMP-dependent protein kinases could favor the maintenance of a higher level of phosphorylated MLCK for longer periods of time.

Animals↗
PubMed1986

Selective retention of organic phosphate esters and phosphonates on aluminium oxide.

Compounds containing the -PO3H2 function, such as monoesters of phosphoric acid and phosphonic acids, specifically bind to aluminium oxide in aqueous solution under experimental conditions where non-phosphorylated compounds are completely desorbed. The bound organic phosphate can be specifically displaced by aqueous solution of inorganic phosphates thus allowing their separation or detection by a technique similar to that of affinity chromatography. The consequences of this finding for phosphate compound biochemistry are discussed.

Aluminum↗
PubMed1986

Ultrasonographic anatomy and diagnosis of fetal uropathies affecting the upper urinary tract. II. Nonobstructive uropathies.

The authors describe the ultrasonographic anatomy and semiology of allowing detection of the main types of fetal non-obstructive uropathies. The results of the author's personal experience in this domain are compared to data from the literature. Differential features of the uropathies are given and the limitations and practical significance of prenatal and postnatal ultrasonography are discussed.

Female↗
PubMed1986

Bioluminescent immunosorbent for rapid immunoassays.

We describe a bioluminescent immunoassay procedure which does not require a separation step to remove excess free label. A luminescent immunosorbent constituted of bacterial luciferase, FMN oxidoreductase, and an antibody coimmobilized on Sepharose is used to determine specifically the label enzyme (glucose-6-phosphate dehydrogenase, coupled to an antigen) bound by a specific antibody. The immunosorbent confines the bioluminescent reaction in a small volume, and the bound label produces NADH, which is directly used by the nearby luciferase FMN oxidoreductase enzyme system. On the contrary NADH produced by dehydrogenases in solution is directly oxidized without emitting light. Dehydrogenases contained in the biological sample do not interfere with the assay, which can be performed directly on 25 microliter of serum. In this paper we describe the general procedure and we analyze the different parameters that must be optimized.

Animals↗
PubMed1986

Bioluminescent immunoassays of progesterone: a comparative study of three different procedures.

Three bioluminescent immunoassay procedures for the determination of serum progesterone are compared. The sensitivity of the three procedures is similar to the sensitivity of radioimmunoassay (10 pg per tube). The use of a bioluminescent immunosorbent is particularly attractive since it has the simpler protocol. No separation step is required to remove the excess of free label (glucose-6-phosphate dehydrogenase coupled to progesterone). The free enzyme activity is not determined since the bioluminescent reaction occurs in the immunosorbent. The intensity of the signal is greater than with other procedures, and biological components contained in ethyl ether extract do not affect the quality of the assay. A good correlation with a radioimmunoassay using tritiated progesterone is obtained (r2 = 0.96) and coefficients of variation of bioluminescent assays are similar (4 to 12%) to those obtained with commercial radioimmunoassays.

Chemical Precipitation↗
PubMed1986

Bioluminescent immunoassay for alpha-fetoprotein.

A bioluminescent immunoassay of alpha-fetoprotein is described. It uses monoclonal antibodies labeled with glucose-6-phosphate dehydrogenase and polyclonal antibodies coimmobilized on Sepharose with bioluminescent enzymes from marine bacteria. The bioluminescent reaction which occurs in the immunosorbent is proportional to the amount of alpha-fetoprotein in the assay. The protocol is simple and rapid, and no separation step is required to remove the excess labeled antibodies. The assay can be performed directly on 25 microliters serum and it is as sensitive as other immunometric assays.

Animals↗