Search PubMed⌕ Search

Biomedical subjects

F Morel

Publications and source records attributed to F Morel.

At least 271 records · Page 15Linked to original sources
PubMedDate not supplied

Both cytochromes P450 2E1 and 1A1 are involved in the metabolism of chlorzoxazone.

Chlorzoxazone, a centrally acting muscle relaxant, was previously shown to be hydroxylated on carbon 6 specifically by cytochrome P450 2E1. Accordingly, this drug has been proposed as a potential noninvasive in-vivo probe for screening the hepatic P450 2E1 activity. This study was carried out to test the specificity of such a substrate when first experiments conducted by using human hepatocyte cultures showed that the chlorzoxazone 6-hydroxylation activity increased after 3-methylcholanthrene treatment of cells. Indeed, the ability of both rat and human hepatocytes to metabolize chlorzoxazone significantly increased after treatments by 3-methylcholanthrene alone or plus ethanol, suggesting the involvement of P450 1A enzymes in this oxidative reaction. Identical results were obtained by in-vivo treatment of rats with four inducers of P450 1A enzymes, namely, beta-naphthoflavone, isosafrole, Arochlor 1254, and 3-methylcholanthrene. Furthermore, the chlorzoxazone 6-hydroxylation activity was inhibited by both alpha-naphthoflavone and dimethyl sulfoxide, both known to inhibit P450 1A and P450 2E1 activities, respectively. Finally, the use of yeasts genetically engineered for expression of human P450 1A1, 1A2, 2C9, and 3A4 demonstrated that P450 1A1 was significantly involved in this catalytic activity. In conclusion, these results taken together suggest that chlorzoxazone should be used with precaution as in-vivo tool for evaluating P450 2E1. However, the relative Km of P450 1A1 and 2E1 for chlorzoxazone and, on the other hand, the relative levels of these two enzymes in the human liver suggest that P450 2E1 would generally be the major form metabolizing chlorzoxazone in-vivo.

Adult↗
PubMedDate not supplied

Sex chromosome aneuploidies in sperm of 47,XYY men.

The sex chromosomal equipment in 26,675 sperm of 47,XYY males was analyzed. A total of 5.78% of the nuclei exhibited sex chromosome hyperhaploidy. Six studies have analyzed the sperm of 10 XYY patients and, although these studies indicated some degree of elimination of the extra Y chromosome during spermatogenesis, a certain percentage of XYY germinal cells may also be able to achieve meiosis and produce sperm with gonosomal disomies. All these studies show an increased incidence of gonosomal aneuploidies in sperm, but there are significant discrepancies concerning the extent of these abnormalities. The global frequencies of sperm with an abnormal number of sex chromosomes ranged from 0.578 to 13.91%, depending on the patients. There are several explanations for these discrepancies: differences attributed to fluorescence in situ hybridization methodology, the use of dual or multicolor FISH, recruitment, interindividual variations, and intraindividual variations. This study reports an additional series obtained from another XYY individual and compares and discusses the data on gonosomal hyperhaploidies in sperm of 47 XYY males using in situ hybridization analyses.

Adult↗
PubMedDate not supplied

Production of urea from arginine in pars recta and collecting duct of the rat kidney.

Urea production from arginine was studied in vitro in the kidney of normal rats in tubule suspensions of the four different renal zones (cortex, outer and inner stripe of outer medulla, and inner medulla), and in individual microdissected nephron segments. Tissue was incubated with L-[guanido-14C]-arginine to measure cellular arginase activity. Addition of urease to the incubate freed 14CO2 from the 14C-urea formed by arginase and released from the cells. CO2 was trapped in KOH and counted. These experiments revealed that significant amounts of urea are produced in the outer stripe and in the inner medulla. This intrarenal urea generation takes place mainly in the proximal straight tubule and in the collecting duct, with increasing activity in these two structures from superficial to deep regions of the kidney. Urea is known to play a critical role in the urinary concentrating process. The fact that some urea can be produced in the mammalian kidney, and that the two structures showing this capacity are straight portions of the renal tubular system descending along the corticopapillary axis suggest that this urea production might play a role in the formation and/or maintenance of the medullary urea concentration gradient.

Animals↗
PubMedDate not supplied

Mitochondrial biochemical activities and heteroplasmy evolution in established D. subobscura cell line.

A mutant strain of drosophila (D. subobscura) has two types of mitochondrial genomes: a small population (20%) identical to that of the wild strain (15.9 kb) and a predominant population (80%) which has undergone a 5-kb deletion affecting more than 30% of the coding zone. Two cell lines were established from homogenates of embryos from mutant and wild strains. The activities of the respiratory complexes measured in the different cell lines are much lower than in the flies, indicating a glycolytic metabolism. Various modifications of the medium composition did not change this metabolic pathway. The mutant cell line has two types of populations of mitochondrial genomes and the heteroplasmy is equivalent to that measured in the mutant strain. However, the biochemical characteristics differ from those observed in the flies (i.e., the decrease of complex I and III activities), and the various systems of compensation for the consequences of the deletion that are showed in the mutant strain are no longer observed. Furthermore, in contrast with observations made on mutant flies, the heteroplasmy appears unstable in the mutant cell lines: after 60 or so generations, it progressively decreases until it disappears completely. The limited importance of mitochondrial energy metabolism in cells may explain the low impact of the mutation on the established cell line, in contrast to what is seen in the mutant strain.

Animals↗
PubMedDate not supplied

[Herpes labialis and genitalis in general medicine].

OBJECTIVE: The purpose of this study was to determine the respective importance of herpes labialis and genitalis in patients consulting general practitioners and ascertain their knowledge and opinions concerning herpes labialis and genitalis in order to analyze patient behavior in case of flare-ups. PATIENTS AND METHOD: A questionnaire was proposed to a representative sample of patients aged 15 years and older seen at consultation by 49 general practitioners participating in the General Medicine Observatory of the French Society of General Practitioners. RESULTS: Among the 4,403 patients who responded, a known history of herpes labialis was reported by 39. 9 p.100 and of herpes genitalis by 2.5 p.100. Their answers to the questions demonstrated insufficient knowledge of avoidable risks of herpes as a sexually transmitted disease, with very significant misunderstanding by men. Among the 1,711 patients who had experienced herpes labialis, 62.9 p.100 initiated self-medication, 29 p.100 preferred to wait and see and 7.5 p.100 sought medical assistance. Among the 108 patients who had experienced herpes genitalis, at the last flare-up 40 p.100 initiated self-medication, 7.5 p.100 preferred to wait and see and 52 p.100 sought medical assistance. The general practitioner was the first physician consulted for both types of herpes. DISCUSSION: This study illustrates the importance of herpes infections in the general medicine patients. It also confirms that new interventional strategies are needed both for health care and for health education.

Adolescent↗
PubMedDate not supplied

Interleukine-6 (IL-6) synthesis and gp130 expression by human pericardium.

Growing evidence shows that cytokines of the IL-6 family play an important regulatory role in heart physiology such as inducing cardiomyocyte hypertrophy. The purpose of this study was to see if IL-6 and its soluble receptors (sIL-6R and sgp130) could be detected in pericardial fluids, and to see if they are produced by the pericardium. We report that human pericardial fluid from patients with coronary pathologies contained IL-6, sIL-6R, and sgp130. However, the levels present in sera and pericardial fluid did not correlate, which suggests local production. This observation was confirmed by in vitro studies demonstrating massive IL-6 production by cultured pericardial samples, which could be strongly inhibited by methylprednisolone. RT-PCR studies revealed that IL-6 was weakly expressed in fresh tissues and strongly induced after culture. In situ hybridisation and immunohistochemical analysis showed that IL-6 and gp130 were mainly present in mesothelial cells. sIL-6R and sgp130 were also produced by pericardium in vitro, and their synthesis was upregulated by methylprednisolone. Taken together, these results demonstrate that IL-6 is present in pericardial fluid and that its presence could be due to synthesis by pericardial tissue. In vitro studies suggest that IL-6 production by this tissue could be strongly induced and regulated. A potential paracrine role of these factors in cardiomyocyte functions in normal or pathological conditions is discussed.

Antigens, CD↗
PubMedDate not supplied

Identification of the B cell derived T cell colony promoting activity to soluble CD23.

We previously reported that supernatants of phytohemagglutinin (PHA)-stimulated normal human B cells (NBCsup) contain a T cell colony promoting activity. NBCsup were able to (a) increase the number of secondary colonies generated under PHA and interleukin-2 (IL-2) stimulation by peripheral blood-derived primary T colony cells, (b) enhance the ability of CD4+ but not CD8+ peripheral blood T cells to form agar colonies in the presence of PHA and IL-2 and (c) support in vitro differentiation of CD2-3-4-8- prothymocytes into CD2+3+4+ T cells. This activity was therefore refered to as Prothymocyte Differentiating Activity (PTDA). Subsequent studies pointed to striking biochemical and cell source homologies between this B cell derived factor and the 25-kDa soluble CD23 (sCD23). sCD23 has been recently found to display prothymocyte differentiating activity.

B-Lymphocytes↗
PubMedDate not supplied

[Full band impressions].

Complete impression with rings achieves the same definition than complete impressions alone and gives a final quality similar to unitary guided impressions. The required steps are the following: 1st clinical: adjustment of the unitary rings, laboratory: elaboration of metallic resin boxing and individual tray, 2nd clinical: complete impression with rings. This method is of a particular interest because of its facility and its possible adaptations to various impression pastes or clinical situations. No gingival conditioning is required to the impression, and increased indications of the method can thus be seen when esthetics or periodontal conditions are a priority.

Alginates↗