Search PubMed⌕ Search

Biomedical subjects

M Lambert

Publications and source records attributed to M Lambert.

At least 235 records · Page 13Linked to original sources
PubMed1994

Metabolism of Pyrene by the Basidiomycete Crinipellis stipitaria and Identification of Pyrenequinones and Their Hydroxylated Precursors in Strain JK375.

The metabolism of pyrene, a polycyclic aromatic hydrocarbon, by submerged cultures of the basidiomycete Crinipellis stipitaria was studied. After incubation for 68 h at 25 degrees C in a 20-liter fermentor with complex medium and 20 mg of pyrene per liter, five metabolites were detected. The compounds were isolated by preparative high-performance liquid chromatography on RP18 and DIOL gels. By UV, infrared, and H nuclear magnetic resonance spectroscopy and mass spectrometry, 1-hydroxypyrene, 1,6-dihydroxypyrene, 1,8-dihydroxypyrene, 1,6-pyrenequinone, and 1,8-pyrenequinone were identified. 1,6- and 1,8-dihydroxypyrene were obtained from fungal cultures for the first time. The formation of these metabolites was confirmed by investigations with [4,5,9,10-C]pyrene.

Journal Article↗
PubMed1994

Calbindin-D9k gene expression in the uterus: study of the two messenger ribonucleic acid species and analysis of an imperfect estrogen-responsive element.

The calbindin D9k (CaBP9k) gene is under strict estrogen control in the rat uterus. This tissue contains two CaBP9k messenger RNA (mRNA) species. We have used primer extension analysis, reverse transcriptase associated with polymerase chain reaction, and RNase H digestion to show that these two mRNA species have the same structural features, including 5'- and 3'-ends, and poly(A) tail length. Our results suggest that the difference in electrophoretic mobilities of the two mRNA species might be due to interaction with another factor. We also analyzed the imperfect estrogen-responsive element (ERE) present on the first 5'-splice site of the rat CaBP9k gene. The oligonucleotide corresponding to the CaBP9k ERE was cloned in the plasmid pBLCAT2 (where the thymidine kinase promoter governs the expression of the chloramphenicol acetyl transferase gene) and transfected into MCF7 cells. This CaBP9k ERE was found to be a hormone-inducible enhancer that worked in an orientation-independent manner on a heterologous promoter and was functional at physiological hormone concentrations. One CaBP9k ERE conferred only weak (about 2-fold) estrogen induction, but two EREs cloned in tandem were strongly synergistic (14- to 16-fold). The CaBP9k ERE also bound to the partially purified estrogen receptor (ER) and to ER expressed in COS cells by gel shift assay. Methylation interference showed that all the guanine residues in both half-sites of the CaBP9k ERE were protected by ER binding. Thus, ER binds to the CaBP9k ERE in a way similar to other EREs. The gel shift assay results indicate that the strong synergistic effect of two EREs cloned in tandem is not due to cooperative binding between the two elements. As the CaBP9k gene is under strong estrogenic control in the uterus in vivo, the imperfect CaBP9k ERE may cooperate with another trans-acting factor to become fully efficient.

Animals↗
PubMed1994

Mutation profiles of phenylketonuria in Quebec populations: evidence of stratification and novel mutations.

Independent phenylketonuria (PKU) chromosomes (n = 109) representing 80% of a proband cohort in Quebec province carry 18 different identified mutations in 20 different mutation/haplotype combinations. The study reported here, the third in a series on Quebec populations, was done in the Montreal region and predominantly on French Canadians. It has identified three novel mutations (A309D, D338Y, and 1054/1055delG[352fs]) and one unusual mutation/RFLP haplotype combination (E280K on Hp 2). The relative frequencies and distribution of PKU mutations were then compared in three regions and population subsets (eastern Quebec, French Canadian; western Quebec, French Canadian; and Montreal, non-French Canadian). The distributions of the prevalent and rare mutations are nonrandom and provide evidence for genetic stratification. The latter and the presence of eight unusual mutation/haplotype combinations in Quebec families with European ancestries (the aforementioned four and M1V, I65T, S349P, and R408W on Hp 1) corroborate demographic and anthropologic evidence, from elsewhere, for different origins of French Canadians in eastern and western Quebec.

DNA Mutational Analysis↗
PubMed1993

Mutations of low-density-lipoprotein-receptor gene, variation in plasma cholesterol, and expression of coronary heart disease in homozygous familial hypercholesterolaemia.

Variation in plasma-cholesterol concentration and the expression of coronary heart disease in patients with homozygous familial hypercholesterolaemia (FH) is well documented, but the underlying reasons for variation are not clearly defined. Because FH is caused by mutations at the low-density-lipoprotein-gene locus, we compared plasma-cholesterol concentrations in 21 FH homozygotes with either the greater than 10 kb deletion (promoter region and exon 1) (11 subjects) or the exon 3 missense (trp66-->gly) mutation (10 subjects) of the low-density-lipoprotein gene. Subjects with the greater than 10 kb deletion had a higher mean plasma-cholesterol concentration than those with the exon 3 mutations (26.7 vs 16.1 mmol/L; p = 0.000006), and there was no overlap in individual plasma-cholesterol concentrations between subjects in the two groups. Although the frequency of coronary heart disease was similar in the two groups, age-of-onset was earlier in subjects with the greater than 10 kb deletion (p = 0.059). Also, coronary deaths were more frequent (p = 0.044) and occurred at an earlier age (p = 0.009) in subjects with the greater than 10 kb deletion. Our results provide evidence that there is less variation in plasma-cholesterol concentrations among FH homozygotes when they are subdivided into groups according to low-density-lipoprotein-receptor-gene defect. Furthermore, differences in plasma-cholesterol concentrations are reflected in the severity of coronary heart disease expression.

Adolescent↗
PubMed1993

Expression of the dystrophin gene in cultured fibroblasts.

The dystrophin whose defect is responsible for Duchenne and Becker muscular dystrophies is present in muscle, brain and cerebellum. We describe here the detection of dystrophin in human cultured skin fibroblasts, L809 cells and murine 3T6 cell line. Dystrophin transcripts initiated at the muscle specific first exon can also be amplified by cDNA-PCR from various fibroblastic cells. The expression of the dystrophin gene in fibroblasts could account for some abnormalities observed in patient's fibroblast cultures.

Animals↗
PubMed1993

Dose-effect relationship of rilmenidine after chronic administration.

The antihypertensive efficacy and acceptability of 3 doses of rilmenidine (0.5, 1 and 2 mg, once daily) and a placebo over a 4 week period have been compared in a randomised, double-blind, parallel-group trial in 60 mild to moderate hypertensive patients. Six patients dropped out: 4 in the 2 mg-group and one in the 1 mg-group because of adverse events, and one in the placebo group for personal reason. The blood pressure was significantly decreased after the 1 and 2 mg doses with the maximum antihypertensive effect already being obtained after 1 mg. A significant dose-effect relationship was shown for supine systolic blood pressure (P = 0.05) but not for the supine diastolic blood pressure. The most beneficial efficacy/acceptability ratio was achieved at the dose of 1 mg once daily, which demonstrated the maximum antihypertensive effect associated with a low incidence of adverse events.

Antihypertensive Agents↗
PubMed1993

Chronic beta-blockade does not influence muscle power output during high-intensity exercise of short-duration.

Patients receiving beta-receptor antagonists for the treatment of hypertension frequently complain of impaired exercise tolerance. To determine whether these medications impair skeletal muscle contractile function, we measured isokinetic muscle function in ten healthy male cyclists receiving nebivolol (N), atenolol (A), propranolol (P) and the calcium channel antagonist diltiazem (D). The subjects performed standardized tests of muscle power on an isokinetic cycle ergometer following subacute ingestion of N, A, P, D and placebo (PL) in a double blind crossover trial. Subjects exercised maximally for 10 s at 90, 110, 120, 130 and 150 rpm with 2-min rest between sessions. Thereafter, they performed a 30-s fatigue test at 120 rpm. Resting heart rate was decreased 13.4%, 21.9% and 14.6% by N, A and P, respectively (P < 0.05 vs PL). Resting systolic blood pressure was decreased 6.7% by A only (P < 0.05 vs PL). Peak power, average power and work done was not different among treatment groups at any crank velocity, nor was there any difference in total work done or rate of work decline in the 30-s test. We concluded from our study that peak isokinetic muscle power during maximal exercise of short duration is not affected by beta-blockade or the calcium antagonist diltiazem. Fatigue during beta-receptor antagonism would not appear therefore to be due to changes in the ability of skeletal muscle to produce peak power output during exercise of short duration.

Adrenergic beta-Antagonists↗
PubMed1993

Lymphokine gene transcription in CD4+CD8- T cells of a type III bare lymphocyte syndrome patient.

In this study we analyzed the impact of a MHC class-II-deficient environment on the differentiation of CD4+CD8- T lymphocytes into functional defined subsets of lymphokine-producing T-helper cells. To this end a CD4+CD8- T-cell line and CD4+CD8- T-cell clones, isolated from PBMCs of a type III BLS patient, were stimulated in vitro with anti-CD3 and PMA and assessed for lymphokine transcription patterns. The results of these analyses show that CD4+CD8- T cells that have matured in a MHC class-II-deficient environment display lymphokine transcription patterns that resemble those of MHC class-II-expressing family control-derived CD4+CD8- T cells.

CD4 Antigens↗
PubMed1993

Unilateral hyperhidrosis associated with intrathoracic IgD lambda myelomatous tumour.

Localized sympathetic over-activity is a rare manifestation of intrathoracic malignancy. We report the case of a 62-year-old woman who presented with a right-sided hyperhidrosis limited to the face, trunk and upper extremities; this revealed a left paraspinal intrathoracic IgD lambda myelomatous tumour. The episodes of sweating were abolished by local radiotherapy, concomitant with the disappearance of the tumour.

Female↗
PubMed1993

Lipoprotein abnormalities associated with cholesteryl ester transfer activity in cystic fibrosis patients: the role of essential fatty acid deficiency.

The purpose of this study was to elucidate the roles of lecithin:cholesterol acyltransferase (LCAT) and cholesteryl ester transfer protein (CETP) in the lipoprotein derangement of cystic fibrosis (CF) patients with respect to their essential fatty acid (EFA) status. Triglyceride enrichment and cholesteryl ester (CE) depletion were observed in the lipoproteins of 22 CF patients. The abnormal chemical composition was more severe in 12 EFA-deficient (EFAD) than in 10 EFA-sufficient (EFAS) patients. Expressed in nmol.L-1.h-1, LCAT activity was higher (P < 0.05) in both EFAS (mean +/- SE, 92.7 +/- 1.9) and EFAD (108.8 +/- 3.0) patients than in control subjects (65.2 +/- 0.9). An equal CE transfer was recorded in the lipoprotein-deficient serum, as a source of CETP activity, in all groups studied by using normal exogenous low-density lipoprotein (LDL) and high-density lipoprotein (HDL). However, in contrast to the maximal amount of CE transferred from endogenous HDL to endogenous apolipoprotein B (apo B) in control subjects, a reduction in CETP activity was seen in CF patients and more pronounced in the EFAD group. These findings indicate that impaired lipoprotein composition may have marked effects on the transfer of CE between HDL and apo B in EFAD CF patients.

Adolescent↗
PubMed1993

Surgical and metabolic aspects of liver transplantation for tyrosinemia.

Tyrosinemia is the diagnosis of a very small percentage of patients undergoing liver transplantation worldwide. Tyrosinemia is endemic within our referral area however, and fully one-third of the liver transplantations at our institution are done for this disease. Since 1986, 15 patients with tyrosinemia (TYR) and 31 patients with various other indications (non-TYR) have undergone a total of 51 liver transplantations. The 36-month actuarial survival for TYR patients is 87%, compared with 74% for non-TYR patients. Liver transplantation for hereditary tyrosinemia and other metabolic disorders without portal hypertension or previous portohepatic operations is notably easier to perform. Intraoperative blood loss was less, length of hospital stay was shorter, and incidence of infections was lower in TYR than in non-TYR patients. Less than 10% of TYR patients had foci of hepatocellular carcinoma at the time of transplantation. For this reason, and while most patients with tyrosinemia will eventually require liver transplantation, our results do not support systematic early transplantation before the age of two years.

Adolescent↗
PubMed1993

Lymphocytic gastritis: an unusual cause of hypoproteinaemia.

Lymphocytic gastritis (LG) is a disorder characterized by diffuse infiltration of the gastric epithelium by small lymphocytes. Its cause remains largely unknown, although several arguments favour an immune origin. Hypoproteinaemia induced by leakage of plasma proteins into the gastric lumen is a rare complication of LG. We report here on three cases of LG whose presenting symptom was lower limb oedema secondary to hypoproteinaemia. The diagnosis was based on radiological, endoscopic and histopathological findings. Radionuclide studies allowed confirmation of the loss of proteins in the stomach. Therapy with omeprazole or H2-receptors antagonists proved to be successful. The relationship between LG and varioliform gastritis is reviewed.

Aged↗
PubMed1993

Haematological changes and infectious complications in anorexia nervosa: a case-control study.

To determine the prevalence of haematological abnormalities in patients with anorexia nervosa (AN), and assess the relationships between these changes, the severity of AN and the propensity to infections, we retrospectively studied 67 patients who met the DSM-III-R diagnostic criteria for AN. We recorded physical findings and routine haematological data on admission, and infectious events during hospitalization. The patients were compared with 67 normal controls matched for age and sex. Mean haemoglobin (Hb) was normal but lower in AN patients than in controls (131 +/- 19 vs. 137 +/- 11 g/l, p = 0.03) and the prevalence of anaemia (Hb < 120 g/l) was higher in the AN group (27% vs. 1.5%, p < 0.0001). Patients had a lower leucocyte count (4.94 +/- 1.9 vs. 6.78 +/- 2.4 x 10(9)/l, p < 0.0001), and increased prevalence of leucopenia (< 4 x 10(9) cells/l)(36% vs. 1.5%, p < 0.0001), neutropenia (< 1500 x 10(6) cells/l)(17% vs. 0%, p = 0.0015) and thrombocytopenia (< 150 x 10(9)/l) (10% vs. 0%, p = 0.03). Only 2 patients (3%) had pancytopenia, but 9/17 patients with anaemia (53%) also had leucopenia. There was a slight but significant correlation between body-mass index (BMI) and total leucocyte, neutrophil and red blood cell counts. Severe infectious complications occurred in 9% of AN patients vs. 0% in controls (p = 0.01); they were more frequent with neutropenia (relative risk, 15.1: 95% CI, 10-20.2) or low (< 12) BMI (relative risk, 11.6: 95% CI, 6.6-16.6) on admission. Compared with controls, AN patients thus had an increased prevalence of anaemia, leucopenia and thrombocytopenia.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗