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Biomedical subjects

N Bernard

Publications and source records attributed to N Bernard.

At least 73 records · Page 4Linked to original sources
PubMed1995

D175 discriminates between NADH and NADPH in the coenzyme binding site of Lactobacillus delbrueckii subsp. bulgaricus D-lactate dehydrogenase.

The NAD-dependent D-(-)-lactate dehydrogenase (D-LDH) from Lactobacillus delbrueckii subsp. bulgaricus (in short, L. bulgaricus) has been modified at position 175 by site-directed mutagenesis, changing a conserved aspartate residue into an alanine. The D175A mutant enzyme displays a 40-fold shift in coenzyme preference from NADH to NADPH. This demonstrates that D175 truly belongs to the amino acid consensus GXGXXGX(17)D (where X represents any residue) which is the signature of the coenzyme binding site of most NAD-dependent dehydrogenases.

Alanine↗
PubMed1995

[Effect of primary prevention of Pneumocystis carinii pneumonia on the inaugural clinical and biological presentation of AIDS: 624 cases (Aquitaine Cohort, 1985-1994)].

In a cohort of HIV-infected patients, this study compares the clinical and immunological features at the time of AIDS diagnosis of patients who either received primary Pneumocystis carinii prophylaxis (P+; n = 335) or who did not (P-; n = 289). Frequency of P carinii pneumonia was lower in P+ than in P- patients (14.9% vs 26.0%; p < 0.001). Conversely, toxoplasmic encephalitis, esophageal candidiasis, cytomegalovirus disease and M avium complex disease were more frequent in P+ patients. CD4+ count (median/mm3) at the time of AIDS diagnosis was lower in P+ than in P- patients: 22 vs 97 (p < 0.001); this suggests that early intervention delays the onset of AIDS for about one year. While searching for new prevention strategies against other opportunistic infections, efforts should be expanded to improve prophylaxis of P carinii pneumonia which remains in France the most frequent first AIDS-related illness.

AIDS-Related Opportunistic Infections↗
PubMed1995

Pharmacokinetics of piroximone after oral and intravenous administration to patients with renal insufficiency.

The pharmacokinetics of piroximone (PI) were determined in patients with renal failure (inulin clearance less than 50 ml min-1 per 1.73 m2) using two protocols: (a) 10 patients received a single i.v. infusion of 0.5 mg kg-1 PI and the data were compared with those from seven healthy subjects receiving the same regimen; (b), a single oral dose of either 25 or 50 mg PI was given to 20 patients. PI concentrations were assayed by h.p.l.c. in plasma and urine over 48 h. After i.v. administration to healthy subjects PI was distributed rapidly and eliminated with a mean half-life of 1.3 +/- 0.2 h. The urinary recovery of unchanged PI was 64% of the dose. In the patients the extent of renal elimination of PI was decreased (-78%) in relation to the degree of renal insufficiency as assessed by inulin clearance (r = 0.97, P < 0.0001). Mean Cmax, AUC and t1/2,z values after i.v. infusion were increased by 47%, 127% and 77%, respectively, in comparison with healthy subjects. Similar results were obtained after oral administration. Until chronic dosing studies are undertaken, PI dosage should be adapted in relation to renal function.

Administration, Oral↗
PubMed1995

Comparative studies on check-bite and central-bearing-point method for the remounting of complete dentures.

Thirty-six complete dentures were remounted both with check-bite as well as central-bearing-point (CBP) registration. The mandibular or denture position was registered in the condylar area three times with each method. Two independent operators carried out the registrations. One half of patients had their occlusion equilibrated according to the check-bite registration, the other half in the central-bearing-point position. After individual determination of the hinge axis the upper dentures were mounted by a face-bow transfer into a Dentatus articulator. A total of six registrations was performed and repeatedly compared in the condylar area in three dimensions using a computer supported measuring device. The reproducibility of the check-bite registration was 0.37 +/- 0.33 mm, with a maximum of 1.77 mm. For the central-bearing-point method this was 0.29 +/- 0.26 mm with a maximum of 1.56 mm. The mean difference in condylar position between both methods was 0.66 +/- 0.55 mm with a maximum of 4.02 mm. A third independent operator re-examined 30 of the patients 2-3 weeks after the remounting and evaluated the adaptation to the new dentures. Those patients whose dentures were equilibrated with the central-bearing-point method tended to cope better with their dentures and suffered on average from fewer pressure spots.

Adaptation, Physiological↗
PubMed1995

Cloning, nucleotide sequence, and transcriptional analysis of the Pediococcus acidilactici L-(+)-lactate dehydrogenase gene.

Recombinant plasmids containing the Pediococcus acidilactici L-(+)-lactate dehydrogenase gene (ldhL) were isolated by complementing for growth under anaerobiosis of an Escherichia coli lactate dehydrogenase-pyruvate formate lyase double mutant. The nucleotide sequence of the ldhL gene predicted a protein of 323 amino acids showing significant similarity with other bacterial L-(+)-lactate dehydrogenases and especially with that of Lactobacillus plantarum. The ldhL transcription start points in P. acidilactici were defined by primer extension, and the promoter sequence was identified as TCAAT-(17 bp)-TATAAT. This sequence is closely related to the consensus sequence of vegetative promoters from gram-positive bacteria as well as from E. coli. Northern analysis of P. acidilactici RNA showed a 1.1-kb ldhL transcript whose abundance is growth rate regulated. These data, together with the presence of a putative rho-independent transcriptional terminator, suggest that ldhL is expressed as a monocistronic transcript in P. acidilactici.

Amino Acid Sequence↗
PubMed1995

Pediococcus acidilactici ldhD gene: cloning, nucleotide sequence, and transcriptional analysis.

The gene encoding D-lactate dehydrogenase was isolated on a 2.9-kb insert from a library of Pediococcus acidilactici DNA by complementation for growth under anaerobiosis of an Escherichia coli lactate dehydrogenase and pyruvate-formate lyase double mutant. The nucleotide sequence of ldhD encodes a protein of 331 amino acids (predicted molecular mass of 37,210 Da) which shows similarity to the family of D-2-hydroxyacid dehydrogenases. The enzyme encoded by the cloned fragment is equally active on pyruvate and hydroxypyruvate, indicating that the enzyme has both D-lactate and D-glycerate dehydrogenase activities. Three other open reading frames were found in the 2.9-kb insert, one of which (rpsB) is highly similar to bacterial genes coding for ribosomal protein S2. Northern (RNA) blotting analyses indicated the presence of a 2-kb dicistronic transcript of ldhD (a metabolic gene) and rpsB (a putative ribosomal protein gene) together with a 1-kb monocistronic rpsB mRNA. These transcripts are abundant in the early phase of exponential growth but steadily fade away to disappear in the stationary phase. Primer extension analysis identified two distinct promoters driving either cotranscription of ldhD and rpsB or transcription of rpsB alone.

Amino Acid Sequence↗
PubMed1995

[The intraoral determination of the sagittal condyle path inclination during face-bow recording].

In a clinical trial involving 40 fully dentate persons, three different intraoral procedures to determine the sagittal condyle path inclination were checked for accuracy. In each test person the condyle path inclination was determined three times, i.e. by the central bearing point method, the protrusive check-bite method and by a protrusive bite record integrated in the bite fork. At 5 mm of protrusion the reproducibility of the results obtained with the central bearing point method (mean value 2.1 +/- 2.0 degrees) were far better than that with either of the two other methods; the difference was statistically significant. The protrusive check-bite records and the protrusive bite fork records did not differ from each other as far as their accuracy was concerned (mean values 3.6 +/- 2.1 degrees and 3.4 +/- 1.6 degrees, respectively). The mean value of the condyle path inclination to the hinge axis infra-orbital plane in the sample was about 50 +/- 8 degrees regardless of the method used. Thus, protrusion records can be integrated in the face bow transfer.

Adult↗
PubMed1994

NAD(+)-dependent D-2-hydroxyisocaproate dehydrogenase of Lactobacillus delbrueckii subsp. bulgaricus. Gene cloning and enzyme characterization.

A genomic library from Lactobacillus delbrueckii subsp. bulgaricus was used to complement an Escherichia coli mutant strain deficient for both lactate dehydrogenase and pyruvate formate lyase, and thus unable to grow anaerobically. One recombinant clone was found to display a broad specificity NAD(+)-dependent D-2-hydroxyacid dehydrogenase activity. The corresponding gene (named hdhD) was subcloned and sequenced. The deduced amino acid sequence of the encoded enzyme indicates a 333-residue protein closely related to D-2-hydroxyisocaproate (i.e. 2-hydroxy-4-methyl-pentanoate) dehydrogenase (D-HO-HxoDH) of Lactobacillus casei and other NAD(+)-dependent D-lactate dehydrogenases (D-LDH) from several other bacterial species. The hdhD gene was overexpressed under the control of the lambda phage PL promoter and the enzyme was purified with a two-step method. The L. delbrueckii subsp. bulgaricus enzyme, like that of L. casei, was shown to be active on a wide variety of 2-oxoacid substrates except those having a branched beta-carbon.

Alcohol Oxidoreductases↗
PubMed1994

Pharmacokinetics of ganciclovir in a patient undergoing chronic haemodialysis.

The pharmacokinetics of ganciclovir was evaluated in a 73-year old anuric, haemodialyzed patient given 1.25 mg.kg-1 at the end of each haemodialysis session, three times per week. A biexponential decrease in plasma ganciclovir was observed, with a peak concentration of 3.7 mg.l-1 followed by a steady state value of 2.6 mg.l-1 for almost 40 h. The total plasma clearance was 0.05 ml.min-1.kg-1, the volume of distribution at steady state was 0.6 l.kg-1, the elimination half life was 132 h, the area under curve was 372 micrograms.h.ml-1, the mean residence time was 190 h, and the percentage of ganciclovir cleared from plasma after a 5 h haemodialysis session was 52.1%. The simulated pharmacokinetics over one month, following the same scheme of administration, did not suggest marked accumulation of ganciclovir. These results were obtained after a reduction of 58% in the recommended dose in patients with impaired renal function.

Aged↗
PubMed1994

Two dimensional gel electrophoresis identifies minor differences in immunologically cross-reactive 64 KDa autoantigens in the thyroid and eye muscle.

Among the candidate eye muscle autoantigens proposed as being relevant to the pathogenesis of thyroid-associated ophthalmopathy (TAO), a 64 kDa membrane autoantigen appears to be most closely associated with the eye disorder. We have examined the tissue localization and some of the physicochemical properties of this molecule in 3 human tissues, namely thyroid (THY), eye muscle (EM) and skeletal muscle (SKE), and in pig eye muscle (PEM), by two-dimensional (2-D) [isoelectric focusing (IEF)/sodium dodecyl polyacrylamide gel electrophoresis (SDS-PAGE)] gel electrophoresis followed by Western blotting. Antibody probes used were whole sera from patients with TAO and antibodies affinity purified from TAO sera by binding to, and elution from, a sepharose-4B column conjugated with D1, a 98 amino acid peptide fragment of a recombinant 64 kDa thyroid autoantigen. Soluble membrane proteins eluted from a slice of SDS-PAGE gel containing 60-70 kDa material was prepared from the four tissues and used as antigen for 2-D gel separation. The presence of a 64 kDa antigen in THY and EM recognized by sera from patients with TAO, but only rarely by those from normal individuals, was confirmed. Pretreatment of the eluted 60-70 kDa material with N-Glycosidase F to eliminate charge heterogeneity resulting from glycosylation differences, changed the pI and MW of molecules recognized by TAO sera, in THY and EM. This suggests that the 64 kDa molecule(s) in EM and THY targeted by sera from patients with TAO are glycoproteins and that they are different in the two tissues.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Cross-reactive antibodies in the serum of balb/c mice immunized with thyroid or eye muscle membranes.

During the course of immunizing balb/c mice with eye muscle (EM) or thyroid (THY) membranes for monoclonal antibody (MCAB) production their sera frequently contain antibodies which react against both EM and THY membranes in enzyme-linked immunosorbent assay (ELISA) and SDS-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blotting. In order to further study this phenomenon we have analyzed sera from 27 balb/c mice, including 10 that were studied serially, and their tissues examined histologically at sacrifice. Following immunization serum and, in some cases, the corresponding MCAB produced by fusion of the mouse spleen cells with a mouse myeloma cell line, were tested for EM and THY cross-reactivity in an ELISA and by immunoblotting. The number of antibodies demonstrated in Western blotting identified as bands of reactivity, and ELISA levels, expressed as optical density--increased with time, each peaking at around 10-12 weeks. THY and EM antibody cross-reactivity was demonstrated in the majority of mice, serum from mice immunized with THY membranes reacting with these membranes as well as with pig EM membranes in both ELISA and immunoblotting and, conversely, sera from mice immunized with pig EM membranes also reacting with THY membranes in the two tests. In Western blotting a variety of THY and EM-reactive antibodies were demonstrated including those directed against a 64 kDa protein, shown to be an important autoantigen in thyroid-associated ophthalmopathy. There was also some cross-reactivity with brain membranes, used as control antigen in both tests and in immunization, although to a lesser degree, but very little to liver and orbital connective tissue membrane.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

[Hyperthyroidism and hypersecretion of chorionic gonadotropin in gastric adenocarcinoma].

We report a case of hyperthyroidism complicating and revealing a metastatized adenocarcinoma of the stomach with high circulating levels of human chorionic gonadotropin and its beta component. To our knowledge, this is the first reported case of a non-trophoblastic tumor with hyperthyroidism and secreting quantities of these hormones. High circulating levels of beta component in such patients have been considered to be a sign of malignancy. The mechanisms of thyroid stimulation could be related to the biological activity of certain forms of the human chorionic gonadotropin.

Adenocarcinoma↗
PubMed1994

Influence of hepatic impairment on the pharmacokinetics of nefazodone and two of its metabolites after single and multiple oral doses.

The pharmacokinetics of nefazodone, a new antidepressant, and two of its active metabolites, hydroxy-nefazodone and m-chlorophenylpiperazine, were determined after single and repeated oral escalating doses of 50, 100 and 200 mg, in healthy volunteers (n = 13) and patients with mild (n = 13) or severe (n = 6) hepatic impairment. All subjects were classified according to their dextromethorphan oxidation capacity. In healthy volunteers, nefazodone was rapidly absorbed after which the plasma concentrations declined with an apparent elimination half-life ranging from 2.7 +/- 1.7 h to 10.2 +/- 4.4 h according to the dosage. Hydroxy-nefazodone appeared rapidly in plasma and its time-course (half-life ranging 1.4 +/- 0.9 h to 6.5 +/- 1.6 h) paralleled that of nefazodone, while mCPP showed low and variable concentrations. The disproportionately longer half-life and more markedly increased Cmax and AUC0-48 which was observed with dosage and treatment duration, and moreover AUC0-12 at steady state significantly higher (P < 0.05) than AUC0-infinity after single dose demonstrated the non-linearity of the pharmacokinetics of nefazodone and hydroxy-nefazodone. The constant molar AUC0-48 hydroxy-nefazodone/nefazodone ratio (0.32 +/- 0.04) and the close correlation (r2 = 0.95) between kinetic parameters of nefazodone and hydroxy-nefazodone suggest that nefazodone hydroxylation is not a saturable process. The kinetics of nefazodone and metabolites were significantly affected by severe but not by mild liver insufficiency. As a consequence, on a pharmacokinetic basis nefazodone should be used with caution in severely hepatic impaired patients.

Adolescent↗
PubMed1994

Use of homologous expression-secretion signals and vector-free stable chromosomal integration in engineering of Lactobacillus plantarum for alpha-amylase and levanase expression.

The genuine alpha-amylase gene from Bacillus licheniformis (amyL) is not expressed in Lactobacillus plantarum, but replacement of the amyL promoter by a strong L. plantarum promoter leads to efficient expression of the gene and secretion of more than 90% of the alpha-amylase into the culture supernatant. A series of L. plantarum genetic cassettes (transcription and translation with or without secretion) were cloned by translation fusion of random DNA fragments to the silent amyL coding frame in the pGIP212 probe vector (P. Hols, A. Baulard, D. Garmyn, B. Delplace, S. Hogan, and J. Delcour, Gene 118:21-30, 1992). Five different cassettes were sequenced and found to harbor genetic signals similar to those of other gram-positive bacteria. The functions of the cloned cassettes and the cassettes isolated previously from Enterococcus faecalis were compared in E. faecalis and L. plantarum, respectively. All signals were well recognized in L. plantarum, but cassettes isolated from L. plantarum led to a low level of amylase production in E. faecalis, suggesting that the L. plantarum signals are more species specific. Six transcriptional or translational fusions were constructed to express the Bacillus subtilis levanase gene (sacC) in L. plantarum. All of these constructions were capable of inducing levanase production and secretion in the culture supernatant, and, furthermore, L. plantarum strains harboring the most efficient fusions could grow in MRS medium containing inulin as the major carbon source. Finally, a two-step chromosomal integration procedure was used to achieve efficient stabilization of an amylase construction without any residual resistance marker or vector sequence.

Amino Acid Sequence↗