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Biomedical subjects

N Lambert

Publications and source records attributed to N Lambert.

At least 55 records · Page 3Linked to original sources
PubMed1989

[Current bacteriologic status and therapeutic results in acute otitis media in children aged over 3 months].

355 children, 3 months to 15 years old, presenting with acute otitis media, underwent a bacteriological study of otitis exsudate. From November 1985 to September 1987, 162 myringotomy and 149 acute otitis media spontaneously discharging were studied in Paris. From October 1981 to September 1987, 62 myringotomy and 46 spontaneously discharging acute otitis were studied in Valognes. There was none pathogenic bacterium in respectively 20 and 14% of the samples. Two or more pathogenic bacterium were isolated in 24 and 7% of the samples. In Paris as in Valognes, 3 pathogens were predominants: Haemophilus (17% were beta-lactamase producers), S. pneumoniae and Staphylococcus. There was only 5 and 3% Streptococcus pyogenes, 2% Branhamella catarrhalis in Paris, none in Valognes. Pseudomonas was present only in case of spontaneous otorrhea, even if recent. For the moment, the combination of amoxicillin with clavulanic acid is not our first treatment in case of acute otitis media in children. Actually we prescribe amoxicillin alone, 50 to 100 mg/kg/day. If the child is allergic to beta lactamin, we give him the combination of trimethoprime and sulfamethoxazole.

Acute Disease↗
PubMed1989

[Staphylococcal toxic shock in children].

Toxic shock syndrome (TSS) is reported in 2 children. TSS occurred 10 days after an accidental injury of the fore foot in one case and 5 days following surgery for severe uretero-vesical reflux in the other. The clinical illness was defined by the case definition formulated for epidemiologic studies (CDC, 1982). The diagnosis was confirmed by isolation of a Staphylococcus aureus strain producing TSST, at the infected site. Toxin-induced mediators such as interleukin I and Tumor Necrosis Factor have been incriminated in septic shock with multivisceral involvement. As in our 2 cases, the syndrome may be delayed or even absent.

Adolescent↗
PubMed1988

Isolation and expression of a pea vicilin cDNA in the yeast Saccharomyces cerevisiae.

A cDNA clone containing the complete coding sequence for vicilin from pea (Pisum sativum L.) was isolated. It specifies a 50,000-Mr protein that in pea is neither post-translationally processed nor glycosylated. The cDNA clone was expressed in yeast from a 2 micron plasmid by using the yeast phosphoglycerate kinase promoter and initiator codon. The resultant fusion protein, which contains the first 16 amino acid residues of phosphoglycerate kinase in addition to the vicilin sequence, was purified and subsequently characterized. It has slightly slower mobility on SDS/polyacrylamide-gel electrophoresis than standard pea vicilin and forms a mixture of multimers, some of which resemble the native protein.

Amino Acid Sequence↗
PubMed1987

Application of high-performance liquid chromatography to the assessment of subunit heterogeneity in plant 11S storage globulins.

Plant 11S storage proteins from a wide range of species have been resolved into their component subunits by ion-exchange fast protein liquid chromatography under denaturing conditions. The complex profiles obtained were reproducible and characteristic for each plant species analysed. The technique is shown to have distinct advantages over the more conventional electrophoretic approaches used to assess 11S subunit heterogeneity. The potential for the fast protein liquid chromatographic method as a simple screening system is discussed.

Chromatography, High Pressure Liquid↗
PubMed1987

Resolution of pea legumin subunits by high-performance liquid chromatography.

Pea legumin was dissociated into its component subunits by 6 M urea: these were subsequently fractionated by FPLC using a combination of Mono P, Mono Q, and Mono S columns. The resolution and speed of separation were greatly improved in comparison with previous fractionations. Twelve discrete fractions were obtained and analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Six "normal" legumin subunits (Mr 60,000) were identified as well as some "large" (Mr 66,000) and "small" (Mr 44,000) subunits. A few polypeptides of unknown origin were also observed. Four subunits were purified to homogeneity as adjudged by electrophoresis and HPLC and in sufficient yields to permit further studies. Anomalous electrophoretic behavior of the legumin subunits was also observed.

Chromatography, High Pressure Liquid↗
PubMed1985

The latency of rat liver microsomal protein disulphide-isomerase.

Protein disulphide-isomerase (PDI) activity was not detectable in freshly prepared rat liver microsomes (microsomal fraction), but became detectable after treatments that damage membrane integrity, e.g. sonication, detergent treatment or freezing and thawing. Maximum activity was detectable after sonication. Identical latency was observed in microsomes prepared by gel filtration and in those prepared by high-speed centrifugation. PDI activity was latent in all particulate subcellular fractions, but not latent in the high-speed supernatant. When all fractions were sonicated to expose total PDI activity, PDI was found at highest specific activity in the microsomal fraction and co-distributed with marker enzymes of the endoplasmic reticulum. Washing of microsomes under various conditions that removed peripheral proteins and, in some cases, bound ribosomes did not remove significant quantities of PDI, nor did it affect the latency of PDI activity. Treatment of microsomes with proteinases, under conditions where the permeability barrier of the microsomal vesicles was maintained intact, did not inactivate PDI significantly or affect its latency. PDI was very readily solubilized from microsomal vesicles by low concentrations of detergents, which removed only a fraction of the total microsomal protein. In all these respects, PDI resembled nucleoside diphosphatase, a marker peripheral protein of the luminal surface of the endoplasmic reticulum, and differed from NADPH: cytochrome c reductase, a marker integral protein exposed at the cytoplasmic surface of the membrane. The data are compatible with a model in which PDI is loosely associated with the luminal surface of the endoplasmic reticulum, a location consistent with the proposed physiological role of the enzyme as catalyst of formation of native disulphide bonds in nascent and newly synthesized secretory proteins.

Animals↗
PubMed1983

Immunological identity between bovine preparations of thiol:protein-disulphide oxidoreductase, glutathione-insulin transhydrogenase and protein-disulphide isomerase.

Five preparations of bovine thiol:protein-disulphide oxidoreductase/glutathione-insulin transhydrogenase (EC 1.8.4.2) and one preparation of bovine liver protein-disulphide isomerase (EC 5.3.4.1) from four different laboratories showed immunological identity in double immunodiffusion and rocket-line immunoelectrophoresis. Consequently, thiol:protein-disulphide oxidoreductase/glutathione-insulin transhydrogenase and protein-disulphide isomerase, formerly classified as two separate enzymes, should be considered as alternative activities of the same enzyme.

Animals↗
PubMed1983

Structural properties of homogeneous protein disulphide-isomerase from bovine liver purified by a rapid high-yielding procedure.

Protein disulphide-isomerase from bovine liver was purified to homogeneity as judged by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis, two-dimensional electrophoresis and N-terminal amino acid analysis. The preparative procedure, a modification of that of Carmichael, Morin & Dixon [(1977) J. Biol. Chem. 252, 7163-7167], is much faster and higher-yielding than previous procedures, and the final purified material is of higher specific activity. The enzyme has Mr 57 000 as determined by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis, both in the presence and in the absence of thiol compounds. Gel-filtration studies on Sephadex G-200 indicate an Mr of 107 000, suggesting that the native enzyme is a homodimer with no interchain disulphide bonds. Ultracentrifugation studies give a sedimentation coefficient of 3.5S, implying that the enzyme sediments as the monomer. The isoelectric point, in the presence of 8 M-urea, is 4.2, and some microheterogeneity is detectable. The amino acid composition is comparable with previous analyses of this enzyme from bovine liver and of other preparations of thiol:protein disulphide oxidoreductases whose relation to protein disulphide-isomerase has been controversial. The enzyme contains a very high proportion of Glx + Asx residues (27%). The N-terminal residue is His. The pure enzyme has a very small carbohydrate content, determined as 0.5-1.0% by the phenol/H2SO4 assay. Unless specific steps are taken to remove it, the purified enzyme contains a small amount (5 mol/mol of enzyme) of Triton X-100 carried through the purification.

Amino Acids↗
PubMed1983

Kinetics and specificity of homogeneous protein disulphide-isomerase in protein disulphide isomerization and in thiol-protein-disulphide oxidoreduction.

The protein disulphide-bond isomerization activity of highly active homogeneous protein disulphide-isomerase (measured by re-activation of 'scrambled' ribonuclease) is enhanced by EDTA and by phosphate buffers. As shown for previous less-active preparations, the enzyme has a narrow pH optimum around pH 7.8 and requires the presence of either a dithiol or a thiol. The dithiol dithiothreitol is effective at concentrations 100-fold lower than the monothiols reduced glutathione and cysteamine. The enzyme follows Michaelis-Menten kinetics with respect to these substrates; Km values are 4,620 and 380 microM respectively. The enzyme shows apparent inhibition by high concentrations of thiol or dithiol compounds (greater than 10 X Km), but the effect is mainly on the extent of reaction, not the initial rate. This is interpreted as indicating the formation of significant amounts of reduced ribonuclease in these more reducing conditions. The purified enzyme will also catalyse net reduction of insulin disulphide bonds by reduced glutathione (i.e. it has thiol:protein-disulphide oxidoreductase or glutathione:insulin transhydrogenase activity), but this requires considerably higher concentrations of enzyme and reduced glutathione than does the disulphide-isomerization activity. The Km for reduced glutathione in this reaction is an order of magnitude greater than that for the disulphide-isomerization activity, and the turnover number is considerably lower than that of other enzymes that can catalyse thiol-disulphide oxidoreduction. Conventional two-substrate steady-state analysis of the thiol:protein-disulphide oxidoreductase activity indicates that it follows a ternary-complex mechanism. The protein disulphide-isomerase and thiol:protein-disulphide oxidoreductase activities co-purify quantitatively through the final stages of purification, implying that a single protein species is responsible for both activities. It is concluded that previous preparations, from various sources, that have been referred to as protein disulphide-isomerase, disulphide-interchange enzyme, thiol:protein-disulphide oxidoreductase or glutathione:insulin transhydrogenase are identical or homologous proteins. The assay, nomenclature and physiological role of this enzyme are discussed.

Animals↗
PubMed1983

Identification of protein disulphide-isomerase as a major acidic polypeptide in rat liver microsomal membranes.

Protein disulphide-isomerase was purified to homogeneity from rat liver by a rapid high-yielding procedure. Structural properties of the pure enzyme were very similar to those of the bovine liver enzyme purified by the same method. The purified rat liver enzyme was subjected to two-dimensional gel electrophoresis in the presence and in the absence of microsomal membranes, and shown to co-electrophorese with a major acidic polypeptide clearly identifiable in the two-dimensional electrophoretic profile of microsomal membranes. This identification was confirmed by peptide 'mapping' of the pure enzyme and of the defined spot from a two-dimensional electrophoresis gel.

Animals↗
PubMedDate not supplied

Purification of a cytosolic enzyme from human liver with phospholipid hydroperoxide glutathione peroxidase activity.

Phospholipid hydroperoxide glutathione peroxidase (PHGPx) is a selenoprotein which inhibits peroxidation of microsomes. The human enzyme, which may play an important role in protecting the cell from oxidative damage, has not been purified or characterized. PHGPx was isolated from human liver using ammonium sulphate fractionation, affinity chromatography on bromosulphophthalein-glutathione-agarose, gel filtration on Sephadex G-50, anion exchange chromatography on Mono Q resin and high resolution gel filtration on Superdex 75. The protein was purified about 112,000-fold, and 12 micrograms was obtained from 140 g of human liver with a 9% yield. PHGPx was active on hydrogen peroxide, cumene hydroperoxide, linoleic acid hydroperoxide and phosphatidylcholine hydroperoxide. The molecular weight, as estimated from non-denaturing gel filtration, was 16,100. The turnover number (37 degrees C, pH 7.6) on (beta-(13-hydroperoxy-cis-9, trans-11-octadecadienoyl)-gamma-palmitoyl)-L-alpha-phosphatidylcho line was 91 mol mol-1 s-1. As reported for pig PHGPx, activity of the enzyme from human liver on cumene hydroperoxide and on linoleic acid hydroperoxide was inhibited by deoxycholate. In the presence of glutathione, the enzyme was a potent inhibitor of ascorbate/Fe induced lipid peroxidation in microsomes derived from human B lymphoblastic AHH-1 TK +/- CHol cells but not from human liver microsomes. Human cell line microsomes contained no detectable PHGPx activity. However, microsomes prepared from human liver contained 0.009 U/mg of endogenous PHGPx activity, which is 4-5 times the activity required for maximum inhibition of lipid peroxidation when pure PHGPx was added back to human lymphoblastic cell microsomes.(ABSTRACT TRUNCATED AT 250 WORDS)

Cells, Cultured↗
PubMedDate not supplied

A dynamic planning framework for nursing homes.

The application of market opportunity analysis offers an extensive information base as well as important implications for market need assessment and cost containment for nursing homes and other organizations. The adaptation of MOA is concerned with alerting the institution to the size and potential of the market, better understanding of the market characteristics, and means for more efficient provision of nursing care and other services. Organized, ongoing information acquisition should enable nursing home administrators to plan and act with foresight rather than react retrospectively (or not at all) to market demands. With systematic planning and adoption of a service user orientation, nursing homes need not be overburdened or ill prepared to meet the diverse and changing needs of the growing segment of the aging.

Health Facility Planning↗
PubMedDate not supplied

[Toxoplasmosis serodiagnosis: comparison of Access Toxo IgM II assay compared to Axsym Toxo IgM and Vidas Toxo IgM assays].

The Access Toxo IgM II test (Beckman Coulter Inc) was evaluated on 1,190 samples from toxoplasmosis serology requests, documented seroconversions, umbilical cord blood or venous blood from healthy newborn, and from newborns with congenital toxoplasmosis. Results were compared to those obtained with Vidas (bioMérieux) and Axsym (Abbott) assays, with Isaga as confirmatory technique. Results obtained with the Access test well correlate those with the Vidas (98.3%) and the Axsym (97.6%) assays. Less "bordeline" results are also observed with the Access test (0.22% versus 0.56% and 1.24% with Vidas and Axsym assays respectively). Results obtained from seroconverted patients prove that the Access assay is more sensitive than Vidas and Axsym assays, with respectively 2 and 4 samples detected earlier for 28 cases studied (recently seroconverted patients). Results obtained using prospective samples and with sequential sera obtained from patients with seroconversion clearly demonstrate that Access Toxo IgM II assay is perfectly adapted to toxoplasmosis diagnosis.

Adult↗