Biomedical subjects

M Philippe

Publications and source records attributed to M Philippe.

At least 19 recordsLinked to original sources

PubMed2004

Nonsense mutations in the essential gene SUP35 of Saccharomyces cerevisiae are non-lethal.

In the present work we have characterized for the first time non-lethal nonsense mutations in the essential gene SUP35, which codes for the translation termination factor eRF3 in Saccharomyces cerevisiae. The screen used was based on selection for simultaneous suppression of two auxotrophic nonsense mutations. Among 48 mutants obtained, sixteen were distinguished by the production of a reduced amount of eRF3, suggesting the appearance of nonsense mutations. Fifteen of the total mutants were sequenced, and the presence of nonsense mutations was confirmed for nine of them. Thus a substantial fraction of the sup35 mutations recovered are nonsense mutations located in different regions of SUP35, and such mutants are easily identified by the fact that they express reduced amounts of eRF3. Nonsense mutations in the SUP35 gene do not lead to a decrease in levels of SUP35 mRNA and do not influence the steady-state level of eRF1. The ability of these mutations to complement SUP35 gene disruption mutations in different genetic backgrounds and in the absence of any tRNA suppressor mutation was demonstrated. The missense mutations studied, unlike nonsense mutations, do not decrease steady-state amounts of eRF3.

Base Sequence↗

PubMed2004

[Characterization of missense mutations in the SUP45 gene of Saccharomyces cerevisiae encoding translation termination factor eRF1].

Collection of missense mutations in the SUP45 gene of Saccharomyces cerevisiae encoding translation termination factor eRF1 has been obtained by different approaches. It has been shown that most of isolated mutations cause amino acid substitutions in the N-terminal part of eRF1 and do not decrease the eRF1 amount. Most of mutations studied do not abolish eRF1-eRF3 interaction. The role of the N-terminal part of eRF1 in stop codon recognition is discussed.

Amino Acid Sequence↗

PubMed2003

Localization of crustacean hyperglycemic and vitellogenesis-inhibiting hormones in separate cell types in the protocerebrum of the woodlouse Armadillidium vulgare (Crustacea, Isopoda).

We gave an accurate immunolocalization of CHH (crustacean hyperglycemic hormone) and VIH (vitellogenesis-inhibiting hormone) in the brain and the sinus gland of the woodlouse Armadillidium vulgare. The two immune sera have been respectively raised against HPLC-purified CHH and against a small peptide derived from the N-terminus of VIH. By immunocytochemistry, we showed that CHH and VIH were synthesized in different perikarya and stored in different axon endings of the sinus gland. As in other crustacean species studied to date, CHH was located in the axon endings filled with the biggest granules. Immunoblotting confirmed that VIH was stored in the sinus glands of both the female and the male. These clear localizations of CHH- and VIH-antigens do not preclude that only one peptide is released from a given type of SG endings and do not rule out that each peptide can be involved in the control of different physiological processes.

Animals↗

PubMed2001

Potentiation of urinary atrial natriuretic peptide interferes with macula densa function.

OBJECTIVES: Neutral endopeptidase (NEP) inhibition potentiated the renal action of Atrial Natriuretic Peptide (ANP) and was associated with appearance of the peptide in the urine, providing evidence of protection of the filtrated peptide along the course of the nephron. The macula densa, composed of epithelial cells, receives ionic information from the urinary compartment via Na-K-2Cl cotransport and influences renin secretion by the myoepithelioïd cells in the afferent arteriole. bNOS constitutively expressed in the epithelial cells of the macula densa is involved in this feed-back. NEP inhibition was associated with the absence of any increase in renin secretion. The hypothesis is that potentiation of urinary ANP by NEP inhibition could limit renin secretion by directly or indirectly targeting the macula densa in vivo. METHODS AND RESULTS: We tested the interaction between NEP inhibition (candoxatril) and Na-K-2Cl inhibition (bumetanide) on electrolyte and ANP urinary excretion, renin secretion, macula densa activity (NADPH diaphorase activity and bNOS mRNA) and TSC-1 mRNA expression in the renal cortex and BSC-1 in the renal medulla of rats treated for 5 days. Bumetanide increased urinary electrolyte excretion whereas candoxatril did not. Candoxatril increased urinary ANP and cyclic GMP excretion. Bumetanide increased renin and aldosterone secretion whereas candoxatril decreased renin secretion. This effect on renin release was associated with an increase in macula densa NADPH diaphorase activity in the bumetanide-treated group which was blunted by candoxatril. Lastly, bumetanide increased TSC-1 mRNA expression in the cortex and this effect was blunted by candoxatril. CONCLUSION: These results suggest that potentiation of ANP by NEP inhibition could interfere with tubular function at different levels and limit renin secretion by a urinary pathway involving macula densa activity.

Animals↗

PubMed2001

Jurassic-Early Cretaceous Gondwanan homoxylous woods: a nomenclatural revision of the genera with taxonomic notes.

The homoxylous fossil woods occurring in the Gondwanan continents of South America, Australia, Africa, India and Antarctica during the Jurassic and Early Cretaceous period are considered here. Original descriptions of the genera and wherever possible, the type material, have been consulted. Applying the rules of the International Code of Botanical Nomenclature, the generic names of the homoxylous woods have been revised from a nomenclatural point of view. According to this review, out of 31 generic names used for woods from the given time interval and area, 6 are illegitimate later nomenclatural synonyms, 1 is a later homonym, and 5 can be considered as taxonomical synonyms. Moreover, 9 genera have been used erroneously. We propose one new generic name (Protaxodioxylon n. gen.) and elsewhere we will propose for conservation, with a conserved type one of the illegitimate names and one of the taxonomic synonyms. As a result, we consider that there are only eighteen generic names correctly quoted for the Jurassic-Early Cretaceous of Gondwana, and we provide a taxonomic key for the corresponding genera. This revision is the first step in systematically comparing northern and southern hemisphere woods.

Journal Article↗

PubMed2001

Uridine uptake inhibition as a cytotoxicity test for a human hepatoma cell line (HepG2 cells): comparison with the neutral red assay.

This study describes a sensitive microassay for measuring cytotoxicity based on the degree of inhibition of RNA synthesis in HepG2 cells. RNA synthesis is measured by the kinetic uptake of radiolabeled uridine. A large number of compounds were tested in a wide range of concentrations. The concentration required to induce 50% inhibition of HepG2 uridine uptake rates (IC(50)) was determined for each compound and used to rank its potency. These IC(50)s were compared with IC(50)s measured with the neutral red assay. 2-acetylaminofluorene, benzo[a]pyrene and methylnitrosourea were not cytotoxic in the neutral red assay. Uridine uptake was always inhibited at lower concentrations than those required in the neutral red assay, suggesting that the uridine uptake assay is a more sensitive indicator of toxic action than the neutral red inclusion. Uridine uptake assay provides a rapid and quantitative method for assessing toxicity in a human cell line. Application of this method to bottled spring waters are described. Due to its high sensitivity and reproducibility, this method provides a suitable tool for screening a great number of samples and will be a helpful test for evaluating food safety and controlling the recycling process of wrapping materials.

2-Acetylaminofluorene↗

PubMed2001

Ancient DNA analysis reveals divergence of the cave bear, Ursus spelaeus, and brown bear, Ursus arctos, lineages.

The cave bear, Ursus spelaeus, represents one of the most frequently found paleontological remains from the Pleistocene in Europe. The species has always been confined to Europe and was contemporary with the brown bear, Ursus arctos. Relationships between the cave bear and the two lineages of brown bears defined in Europe, as well as the origins of the two species, remain controversial, mainly due to the wide morphological diversity of the fossil remains, which makes interpretation difficult [1, 2]. Sequence analysis of ancient DNA is a useful tool for resolving such problems because it provides an independent source of data [3]. We previously amplified a short DNA fragment of the mitochondrial DNA control region (mt control region) of a 40,000-year-old Ursus spelaeus sample [4]. In this paper, we describe the DNA analysis of two mtDNA regions, the control region and the cytochrome b gene. Control region sequences were obtained from ten samples of cave bears ranging from 130,000 to 20,000 years BP, and one particularly well-conserved sample gave a complete cyt b sequence. Our data demonstrate that cave bears split largely before the lineages of brown bears around 1.2 million years ago. Given its abundance, its wide distribution in space and time, and its large morphological diversity, the cave bear is a promising model for direct observation of the evolution of sequences throughout time, extinction periods, and the differentiation of populations shaped by climatic fluctuations during the Pleistocene.

Animals↗

PubMed2001

Pulmonary endothelinergic system in experimental congestive heart failure.

OBJECTIVES: Endothelin-1 (ET-1), plays an important role in the pathophysiology of CHF and the pulmonary endothelium is an early hemodynamic target in diastolic left ventricular dysfunction. Therefore we hypothesized that the lung is a main source of humoral endothelin in CHF and that its secretion is proportional to the degree of heart failure. METHODS AND RESULTS: We used rats with coronary artery ligation as an experimental model of either compensated or decompensated heart failure, depending on infarct size. Reverse transcriptase polymerase chain reaction (RT-PCR) revealed that in the lung, the expression of preproET-1 mRNA was higher in decompensated HF than in control and compensated HF rats (P<0.001). Run-on assay demonstrated that ET-1 overexpression is regulated at a transcriptional level (P<0.01). In contrast, there was no change in ET-1 mRNA expression in aortae, left ventricular myocardium and skeletal muscle. The expression of endothelin-converting enzyme (ECE)-1 mRNA was not modified and the expression of ET(B) receptor mRNA in the congestive lung was significantly lower than in control and compensated HF rats (P<0.0001), while the expression of ET(A) receptor mRNA did not differ between groups. The lung and plasma ET-1 peptide levels were respectively 4.2 and 9 fold higher in the rats with decompensated HF than in control rats (P<0.05; P<0.0001). Organoculture experiments showed that the lung ET-1 peptide secretion level in rats with decompensated HF was higher than that in control rats (P<0.01). In contrast, there was no change in ET-1 peptide secretion by the left ventricular myocardium and skeletal muscle. In plasma of rats with decompensated HF, the rate of bigET-1 conversion to ET-1 was 22%. ET-1 peptide was also present in the pleural effusion of decompensated heart failure. Plasma ET-1 concentration was significantly correlated with upstream markers of left ventricular diastolic dysfunction, with the expression of preproET-1 mRNA in the lung, with lung and pleural ET-1 concentration and with the expression ratio of ET-1/ET(B) receptor mRNA. CONCLUSION: Taken together, these data suggest that overexpression of ET-1 and down-regulation of ET(B) receptors in the lung are determinants of circulating endothelin in CHF. As a corollary, increased plasma endothelin may provide evidence of pulmonary endothelial dysfunction in CHF.

Analysis of Variance↗

PubMed2001

The S. pombe aurora-related kinase Ark1 associates with mitotic structures in a stage dependent manner and is required for chromosome segregation.

Metazoans contain three aurora-related kinases. Aurora A is required for spindle formation while aurora B is required for chromosome condensation and cytokinesis. Less is known about the function of aurora C. S. pombe contains a single aurora-related kinase, Ark1. Although Ark1 protein levels remained constant as cells progressed through the mitotic cell cycle, its distribution altered during mitosis and meiosis. Throughout G2 Ark1 was concentrated in one to three nuclear foci that were not associated with the spindle pole body/centromere complex. Following commitment to mitosis Ark1 associated with chromatin and was particularly concentrated at several sites including kinetochores/centromeres. Kinetochore/centromere association diminished during anaphase A, after which it was distributed along the spindle. The protein became restricted to a small central zone that transiently enlarged as the spindle extended. As in many other systems mitotic fission yeast cells exhibit a much greater degree of phosphorylation of serine 10 of histone H3 than interphase cells. A number of studies have linked this modification with chromosome condensation. Ark1 immuno-precipitates phosphorylated serine 10 of histone H3 in vitro. This activity was highest in mitotic extracts. The absence of the histone H3 phospho-serine 10 epitope from mitotic cells in which the ark1(+) gene had been deleted (ark1.Delta1); the inability of these cells to resolve their chromosomes during anaphase and the co-localisation of this phospho-epitope with Ark1 early in mitosis, all suggest that Ark1 phosphorylates serine 10 of histone H3 in vivo. ark1.Delta1 cells also exhibited a reduction in kinetochore activity and a minor defect in spindle formation. Thus the enzyme activity, localisation and phenotype arising from our manipulations of this single fission yeast aurora kinase family member suggest that this single kinase is executing functions that are separately implemented by distinct aurora A and aurora B kinases in higher systems.

Anaphase↗

PubMed2000

Anterior mandibular osteotomy for tumor extirpation: a critical evaluation.

BACKGROUND: Anterior mandibular osteotomy gives excellent access to the oropharynx for oncologic resections. Although rigid internal fixation has improved results in stability and bone healing, side effects and complications of the surgical procedure must be considered. METHODS: Between 1991 and 1997, 64 patients underwent a transmandibular approach for benign or malignant tumors of the head and neck. Sixty-one of them were included in a 6-month follow-up study. Final results and major and minor complications were recorded. RESULTS: Three (5%) cases of non-union and infection of the osteotomy site required plate removal, curettage, and reosteosynthesis. Occlusal disturbances and local periodontal disease occurred in 2 (3%) patients. Thirty-two (52%) patients complained of sensitivity disturbances, 18 (30%) of temporomandibular joint pain, and 44 (72%) of a limitation in opening the mouth. Six patients (10%) had a cosmetic complaint. CONCLUSION: Dental condition and periodontal care in the vicinity of the osteotomy are important factors in reducing the risk of major complications. Trismus, limitation of joint motion, and pain cannot be directly related to the technique; they depend on the extent of tumor resection and postoperative radiotherapy.

Adolescent↗

PubMed2000

Role of aortic nitric oxide synthase 3 (eNOS) in the systemic vasodilation of portal hypertension.

BACKGROUND & AIMS: In portal hypertension, the mechanisms responsible for nitric oxide (NO) overproduction and vasodilation have not yet been clearly identified. One hypothesis is that NO synthase (NOS) 3 is overactivated because of shear stress in endothelial cells caused by hyperkinetic circulation. The aim of this study was to evaluate aortic NOS3 after a reduction of blood flow by long-time beta-adrenoceptor antagonist administration. METHODS: Propranolol or atenolol was administered by gavage in portal vein-stenosed and sham-operated rats. The vascular reactivity of thoracic aortic rings to phenylephrine, total aortic NOS activity, and aortic NOS3 messenger RNA and protein expressions were studied. RESULTS: After propranolol or atenolol administration, the aortic hyporesponse returned to normal in portal vein-stenosed rats. Total aortic NOS activity was higher in portal vein-stenosed aortas and significantly decreased after beta-blocker administration. Aortic NOS3 expressions were more marked in portal vein-stenosed aortas than in controls, but NOS3 expressions were reduced after propranolol administration. CONCLUSIONS: In portal hypertension, aortic NOS3 activity and expressions are enhanced but return to normal after beta-blocker administration. These results suggest that in portal hypertension, increased shear stress, related to high blood flow, induces enhanced aortic NOS3.

Adrenergic beta-Antagonists↗

PubMed2000

Thrombin induces endothelin expression in arterial smooth muscle cells.

Thrombin has been shown to stimulate endothelin release by endothelial cells, but the ability of thrombin to induce endothelin in nonendothelial cells is less well-known. Incubation of rat aortic smooth muscle cells with thrombin resulted in a stimulation of preproendothelin-1 (preproET-1) mRNA expression. This induction of preproET-1 mRNA expression by thrombin was accompanied by the release of immunoreactive peptide ET-1 into the extracellular medium. The synthetic thrombin receptor activator peptide (TRAP) confirmed ligand-specific receptor action to induce preproET-1 mRNA. Nuclear run-on analysis revealed that the transcriptional rate of preproET-1 mRNA increases twofold after 1 h of incubation with thrombin. In cells treated with thrombin, the half-life of preproET-1 mRNA was identical to that in untreated control cells. These results demonstrated that thrombin regulates endothelin synthesis at a transcriptional level but does not influence mRNA stability. Inhibition of protein kinase C (PKC) with selective inhibitors (chelerythrine and bisindolylmaleimide I) before thrombin stimulation failed to significantly inhibit preproET-1 gene expression. Inhibition of mitogen-activated protein (MAP) kinase kinase and protein tyrosine kinase decreased preproET-1 mRNA expression in thrombin-stimulated smooth muscle cells. Furthermore, addition of an activator of peroxisome proliferator-activated receptors-alpha (PPARalpha), fenofibrate, prevented the preproET-1 gene induction in response to thrombin. These results demonstrated that thrombin-induced endothelin gene transcription involved MAP kinase kinase rather than the PKC cascade in smooth muscle cells, which was repressed by PPARalpha stimulation.

Animals↗

PubMed2000

Molecular plasticity of vascular wall during N(G)-nitro-L-arginine methyl ester-induced hypertension: modulation of proinflammatory signals.

It has previously been reported that hypertension induced by the chronic blockade of NO production is characterized by a proinflammatory phenotype of the arterial wall associated with a periarterial accumulation of inflammatory cells. In the present study, the cellular and molecular mechanisms involved in the luminal and perivascular accumulation of inflammatory cells were evaluated in the aortas of N(G)-nitro-L-arginine methyl ester (L-NAME)-treated rats. Because the medial layer remains intact, putative markers of the resistance of the vascular wall to cell migration and to oxidative stress were also explored. For this purpose, monocyte adhesion, cytokine expression, superoxide anion production, and nuclear factor-kappa B (NF-kappa B) activation were assessed in the aortas of L-NAME-treated rats. Expressions of tissue inhibitor of metalloproteinases-1 (TIMP-1) and heme oxygenase-1 (HO-1) in the aortic wall were also studied as possible markers of such resistance. Chronic blockade of NO production increased ex vivo monocyte adhesion to the endothelium, increased the production of superoxide anions, and activated the NF-kappa B system. In concert with this modification of the redox state of the vascular wall in L-NAME-treated rats, the expression of proinflammatory cytokines interleukin-6, monocyte chemoattractant protein-1, and macrophage colony-stimulating factor was increased. In parallel, expressions of both TIMP-1 and HO-1 were increased. All these changes were prevented by treatment with an angiotensin-converting enzyme inhibitor (Zofenopril). Hypertension associated with a proinflammatory phenotype of the vascular wall induced by blockade of NO production could be due to an increase in oxidative stress, which, in turn, activates the NF-kappa B system and increases gene expression. In parallel, the arterial wall overexpresses factors such as TIMP-1 and HO-1, which could participate in the resistance to cell migration and oxidative stress.

Angiotensin-Converting Enzyme Inhibitors↗

PubMed2000

[Osteolysis after total knee prosthesis].

PURPOSE OF THE STUDY: The aim of our work was to study X-rays showing osteolysis after 5 years and more in 122 prosthesis and to try and assess such complication, often described in the United States but seldom in Europ. MATERIAL: We are dealing here with 122 retaining posterior cruciate ligament, mostly cementless prothesis implanted between 1985 and 1992 84 chromium-cobalt prosthesis (PCA and Themis) implanted in 34 males and 88 females with an average age of 67 (45-81), 87,7 p. 100 had femoral cementless components and 70 p. 100 tibial cementless components. METHODS: All patients were examined and had X-rays at an average of 6,9 years. Specially considered were X-rays showing a possible osteolysis. We looked for possible complication (external laxity, anterior femoral dislocation and polyethylene wear), assessment of the mechanical axis and for clinical results (Hungerford score) RESULTS: Revisions: 19 arthroplasties were revised for PE wear tibial loosening metallosis or patella problems The postoperative score according to Hungerford was 84,5 p. 100 for PCA prosthese and 87 p.100 for the Themis. On the X-rays were only few osteolysis to be found: 9 cases (7,3 p. 100). For the PCA series: 3 femoral osteolysis, 1 tibial at 12 years, and one patellar osteolysis. For the Themis series: no femoral osteolysis, 3 tibial and one patellar osteolysis. Osteolysis are apparent on X-rays in profile for the femur and the patella, and in both profile and frontal X-rays for the tibia. Clinicaly 4 osteolysis really asymptomatic were not re-operated. 5 were revised: one 11 years later for femoral and tibial loosening, two for a patellar loosening, the other two patients had to be reoperated on for metallism (titanium's femoral component) and for those two instances osteolysis were discovered during the complication. DISCUSSION: Osteolysis after TKA appears unusual in our experience without bearing on frequency finded by american authors with a lesser follow-up (Engh 11,1 p. 100 after 4,5y, Peters 16 p. 100 after 2,9 y, Robinson 9,18 p. 100 after 4,6 y). American litteratur analysis shows that the important number of osteolysis is due to: - either to dual-metal using (Co-Cr component with Titanium screws for exemple), - or bad quality of polyethylene (compressed), - or a bad design of former prosthesis. CONCLUSION: Interface illness, linked to the production of wear debris, osteolysis after total knee arthroplasty is rarer than after a hip one, probably because size of debris is different, larger in knee than in hip. It is likely that the improvement of PE quality, design of prosthesis, as well as a better knowledge of osteolysis mechanism will allow to delay this complication wich is in a long term ineluctable.

Aged↗

PubMed2000

S.P.I.C. pedagogical simulator for gynecologic laparoscopy.

Laparoscopic surgery has numerous advantages, but this technique is difficult and requires specific training. This paper presents a simulator for gynecologic laparoscopic surgery called S.P.I.C. (Pedagogical Simulator for Gynecologic Laparoscopic Surgery), specifically designed for teaching. It includes a rail with 3 trocars already in place, and a computer monitor. Training using the simulator is divided into tasks and steps in order of increasing difficulty. Each step consists of training exercises and evaluations. Learning with the simulator is guided by software that allows instructors to personalize their lessons. This prototype has allowed us to put into place training for spatial localization and manipulation of surgical instruments in the abdominal cavity. An evaluation at a clinical site has allowed us to determine the improvements to be made on this prototype. Training with a simulator is part of a resident's regular curriculum and is not meant to replace on site hospital experience. Some imperfections in imaging still exist, due to inevitable technical limitations. Our initial choice was to emphasize realism and "real time", rather than the "aesthetic quality" of the images. Furthermore, by limiting our graphic expectations, we have been able to create a simulator at a reasonable overall price. The S.P.I.C. training tool remains experimental and is still in the process of being developed.

Computer Simulation↗

PubMed1999

Molecular expression of PSMA mRNA and protein in primary renal tumors.

Human prostate-specific membrane antigen (PSMA), a 100-kDa integral transmembrane glycoprotein, is considered to be a highly specific marker of the prostate gland, and has successfully been used as a marker of circulating prostatic epithelial cells. Extended PSMA homology has been demonstrated with a cDNA found in rat cerebral and renal tissues. In this study, we aimed to evaluate the expression of PSMA mRNA in a variety of human renal cancer tissues (n = 20) and cell lines (n = 12). Using reverse transcriptase-polymerase chain reaction, DNA sequencing, blottings, and specific anti-PSMA labelling with CYT 351 antibody, we identified PSMA mRNA and protein in normal and in neoplastic renal tissue. The sequence of the polymerase-chain-reaction products is identical to that of PSMA cDNA derived from prostate tissue. Immunological staining with the CYT 351 reveals that PSMA is expressed mainly in tubular cells. Since PSMA does not appear to be restricted to prostatic tissue, this novel biomarker may prove useful in the staging of renal cancer and in the search for the hematogenous spread of renal cells.

Adenocarcinoma↗

PubMed1999

Estradiol increases rat aorta endothelium-derived relaxing factor (EDRF) activity without changes in endothelial NO synthase gene expression: possible role of decreased endothelium-derived superoxide anion production.

OBJECTIVES: Estradiol is known to exert a protective effect against atherosclerosis, but the mechanism(s) whereby this protection is mediated is/are unclear. However, estradiol-treated castrated animals exhibit increased activity of endothelium-derived relaxing factor (EDRF), which could contribute to vasculoprotection. In the present work, we investigated the molecular mechanism(s) of the enhancement of EDRF activity in the thoracic aorta of oophorectomized female rats given 17 beta-estradiol (E2, 2 or 40 micrograms/kg/day) compared to those given a placebo. METHODS AND RESULTS: The abundance in the thoracic aorta of NO synthase I, II and III mRNA (using RT-PCR) and of NO synthase I, II and III immunoreactive protein (using Western blotting) was unaltered by E2. NO synthase activity (based on arginine/citrulline conversion) in thoracic aorta homogenates did not differ significantly among the three groups, suggesting that NO production was not enhanced by E2. In contrast, lucigenin-enhanced chemiluminescence of aorta from the E2 group was decreased compared to that of the placebo group. Desendothelialization and exogenously added superoxide dismutase suggested that this difference was due to a decrease in extracellular endothelium-derived production of superoxide anion (O2-.). Experiments in cultured bovine aortic endothelial cells confirmed a decreased extracellular production of O2-. in response to ethinylestradiol (1 nM) using both lucigenin-enhanced chemiluminescence and ESR spectroscopy. Luminol-enhanced chemiluminescence revealed that ethinylestradioltreated cultured endothelial cells generated less peroxynitrite (the byproduct of NO-. and O2-. interaction) than control cells. CONCLUSION: Estradiol increases rat aorta EDRF activity in the absence of changes in endothelial NO synthase gene expression. The decreased endothelium-derived generation of O2-. in response to estrogens could account for enhanced EDRF-NO bioactivity and decreased peroxynitrite release. All of these effects could contribute to the vascular protective properties of estrogens.

Animals↗

PubMed1999

Molecular characterization of femA from Staphylococcus hominis and Staphylococcus saprophyticus, and femA-based discrimination of staphylococcal species.

The femA gene encodes a protein precursor which plays a role in peptidoglycan biosynthesis in Staphylococcus aureus and is also considered as a factor influencing the level of methicillin resistance. A femA homologous gene was recently characterized in S. epidermidis, entailing the possibility of femA phylogenetic conservation in staphylococcal species. Accordingly, we assessed the presence of femA homologous genes in S. hominis and S. saprophyticus. Strategy for identification relied upon alignment of S. aureus and D. epidermidis femA sequences and upon identification of potentially conserved regions. Amplifications of portions of the femA genes were performed under permissive annealing conditions, by using several sets of primers designed to match the consensus regions. DNA sequencing of overlapping PCR fragments led to the characterization of the entire femA genes of S. hominis and S. saprophyticus, and provided more precise information on the femA start codon for all five species. The genomic organization of all these femA genes appeared highly conserved, with alternance of homologous and variable regions. On this basis, a consensus sequence of the femA gene was defined and interspecies variations were exploited to design strategies for staphylococci species-specific identification, including multiplex PCR amplification and a reverse hybridization assay.

Amino Acid Sequence↗