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Biomedical subjects

F Tessier

Publications and source records attributed to F Tessier.

At least 19 recordsLinked to original sources
PubMed2000

Risk factors for cortical, nuclear, and posterior subcapsular cataracts: the POLA study. Pathologies Oculaires Liées à l'Age.

The POLA (Pathologies Oculaires Liées à L'Age) Study is a population-based study of cataract and age-related macular degeneration and their risk factors being carried out among 2,584 residents of Sète, southern France, aged 60-95 years. Recruitment took place between June 1995 and July 1997. Cataract classification was based on a standardized lens examination by slit lamp, according to Lens Opacities Classification System III. This paper presents results obtained from cross-sectional analysis of the first phase of the study. In polytomous logistic regression analyses, an increased risk of cataract was found for female sex (cataract surgery: odds ratio (OR) = 3.03; cortical cataract: OR = 1.67), brown irises (cortical, nuclear, and mixed cataracts: OR = 1.61), smoking (cataract surgery: OR = 2.34 for current smokers and OR = 3.75 for former smokers), known diabetes of 10 or more years' duration (posterior subcapsular, cortical, and mixed cataracts and cataract surgery: OR = 2.72), use of oral corticosteroids for at least 5 years (posterior subcapsular cataract: OR = 3.25), asthma or chronic bronchitis (cataract surgery: OR = 2.04), cancer (posterior subcapsular cataract: OR = 1.92), and cardiovascular disease (cortical cataract: OR = 1.96). Decreased risk of cataract was found with higher education (all types of cataract and cataract surgery: OR = 0.59), hypertension (cataract surgery: OR = 0.57), and high plasma retinol levels (nuclear and mixed cataracts and cataract surgery: OR = 0.75 for a 1-standard-deviation increase). Most of the risk factors identified in this study confirm the findings of other studies. The association of cataract with plasma retinol level requires further investigation.

Adrenal Cortex Hormones↗
PubMed1999

Structure and mechanism of formation of human lens fluorophore LM-1. Relationship to vesperlysine A and the advanced Maillard reaction in aging, diabetes, and cataractogenesis.

Human lens crystallins become progressively yellow-brown pigmented with age. Both fluorescent and non-fluorescent protein adducts and cross-links are formed, many of which result from the advanced Maillard reaction. One of them, LM-1, is a blue fluorophore that was earlier tentatively identified as a cross-link involving lysine residues (1). A two-step chromatographic system was used to unequivocally identify and quantitatively prepare a synthetic fluorescent cross-link with lysine residues that had identical UV, fluorescent, and chromatographic properties with both acetylated and non-acetylated LM-1. Proton, (13)C NMR, and molecular mass of the synthetic compound were identical with vesperlysine A, a fluorescent cross-link discovered by Nakamura et al. (2). The fragmentation patterns of vesperlysine A and LM-1 were identical as determined by NMR/mass spectrometry. Lenticular levels of vesperlysine A increase curvilinearly with age and reach 20 pmol/mg at 90 years. Levels correlate with degree of lens crystallin pigmentation and fluorescence and are increased in diabetes, in contrast to N(epsilon)-(carboxymethyl)lysine and pentosidine. Ascorbate, D-pentoses, and D-threose, but neither D-glucose under oxidative conditions, DL-glyceraldehyde, methylglyoxal, glyoxal, nor glycolaldehyde, are precursors. However, addition of C-2 compounds greatly catalyzes vesperlysine A formation from ribose. Thus, vesperlysine A/LM-1 is a novel product of the advanced Maillard reaction in vivo and a specific marker of a diabetic process in the lens that is different from glyco- and lipoxidation.

Adolescent↗
PubMed1999

Age-related macular degeneration and antioxidant status in the POLA study. POLA Study Group. Pathologies Oculaires Liées à l'Age.

OBJECTIVE: To give the levels of antioxidant nutrients in relation to age-related macular degeneration (AMD). METHODS: Pathologies Oculaires Liees a l'Age is a population-based study on cataract and AMD and their risk factors, carried out on 2584 inhabitants of Sete, France. Age-related macular degeneration was defined by findings from fundus photographs according to an international classification. Biological measurements were taken from fasting blood samples. RESULTS: After multivariate adjustment, plasma alpha-to-copherol levels showed a weak negative association with late AMD (P = .07). Lipid-standardized plasma alpha-tocopherol levels showed a significant negative association with late AMD (P= .003): the risk of late AMD was reduced by 82% in the highest quintile compared with the lowest. Similarly, lipid-standardized plasma alpha-tocopherol levels were inversely associated with early signs of AMD (odds ratio, 0.72 [95% confidence interval, 0.53-0.98]; P=.04). No associations were found with plasma retinol and ascorbic acid levels or with red blood cell glutathione values. COMMENT: These results suggest that vitamin E may provide protection against AMD. Only randomized interventional studies could prove the protective effect of vitamin E on AMD.

Aged↗
PubMed1999

Outcome of fetuses diagnosed with atrioventricular septal defect.

OBJECTIVE: To quantify the association of prenatally diagnosed atrioventricular septal defect with Down syndrome and to evaluate its impact on obstetric and neonatal outcomes. METHODS: Charts of 42 cases of atrioventricular septal defect diagnosed by fetal echocardiography from July 1985 to July 1997 were reviewed for prenatal history and outcome data (pregnancy outcome, pathologic confirmation, postnatal echocardiographic findings, and neonatal outcome). Statistical analysis was done using Fisher exact test and odds ratios. RESULTS: The mean gestational age at diagnosis was 26 weeks. Four cases could not be confirmed antenatally on repeat echocardiograms and were excluded. Reasons for referral of the remaining 38 fetuses included an abnormal four-chamber view in 76%. Twenty-two fetuses (58%) had abnormal karyotypes: 19 trisomy 21, one trisomy 18, one trisomy 13, and one mosaicism. The cardiac lesions were isolated in 20 fetuses (53%). After excluding cases of termination, ten of 12 fetuses (83%) with Down syndrome survived, compared with seven of 13 (54%) with normal karyotypes (P = .125). The odds of trisomy 21 were 16 times higher (95% confidence interval 3.0, 85.3) in fetuses with isolated cardiac lesions compared with those with associated cardiac anomalies. CONCLUSION: Prenatal diagnosis of atrioventricular septal defect was associated with a 58% risk of aneuploidy (mainly trisomy 21). Down syndrome fetuses with this cardiac anomaly appeared to have a better survival rate than fetuses with normal karyotypes. Our sample did not have enough power to show a statistically significant difference. When an isolated atrioventricular septal defect was diagnosed prenatally, the odds of trisomy 21 were significantly higher than when other associated cardiac lesions were diagnosed. This information should be considered in prenatal counseling for atrioventricular septal defect.

Adult↗
PubMed1999

Presence of mefA and mefE genes in Streptococcus agalactiae.

Eighteen unrelated clinical isolates of Streptococcus agalactiae with the M phenotype harbored an mef gene. DNA sequencing showed that one of nine strains contained mefA (producing one amino acid substitution), whereas the remaining eight carried mefE (identity, 100%). Restriction analysis of PCR products indicated that the nine other strains also contained mefE.

Bacterial Proteins↗
PubMed1999

Muscle enzyme release does not predict muscle function impairment after triathlon.

BACKGROUND: We sought to determine the effects of a long distance triathlon (4 km swim, 120 km bike-ride, and 30 km run) on the four-day kinetics of the biochemical markers of muscle damage, and whether they were quantitatively linked with muscle function impairment and soreness. METHODS EXPERIMENTAL DESIGN: Data were collected from 2 days before until 4 days after the completion of the race. PARTICIPANTS: Twelve triathletes performed the triathlon and five did not. MEASURES: Maximal voluntary contraction (MVC), muscle soreness (DOMS) and total serum CK, CK-MB, LDH, AST and ALT activities were assessed. RESULTS: Significant changes after triathlon completion were found for all muscle damage indirect markers over time (p < 0.0001). MVC of the knee extensor and flexor muscles decreased over time (p < 0.05). There is disparity in the time point at which peak values where reached for DOMS, MVC and enzyme leakage. There is no correlation between serum enzyme leakage, DOMS and MVC impairment which occur after triathlon. CONCLUSIONS: Long distance triathlon race caused muscle damage, but extent, as well as muscle recovery cannot be evaluated by the magnitude of changes in serum enzyme activities. Muscle enzyme release cannot be used to predict the magnitude of the muscle function impairment caused by muscle damage.

Adult↗
PubMed1998

Effect of pH, phosphate and copper on the interaction of glucose with albumin.

Protein glycation is believed to play an important role in the development of long-term disorders associated with diabetes. Previous studies have shown that copper could activate this process; however, these experiments were performed under non-physiological conditions. In this study, in vitro experiments were carried out at near-physiological conditions to examine the catalytic activity of copper on the interaction of albumin with glucose. Changes in pH and phosphate buffering capacity were shown to affect albumin glycation. Under stable pH conditions, copper activates albumin glycation only at low protein concentrations (< 30 g l(-1)). Copper had no effect on albumin glycation at higher protein concentrations probably because the metal is chelated by the protein.

Buffers↗
PubMed1998

Molecular characterization of a TEM-21 beta-lactamase in a clinical isolate of Morganella morganii.

A clinical isolate of Morganella morganii, with reduced susceptibility to expanded-spectrum cephalosporins and aztreonam, was found to produce an extended-spectrum beta-lactamase with a pI of 6.4. The nucleotide sequence of the encoding gene was that of the gene encoding TEM-21. This is the first molecular characterization of an extended-spectrum beta-lactamase in M. morganii.

Base Sequence↗
PubMed1998

Decrease in vitamin C concentration in human lenses during cataract progression.

Cataract formation is believed to result from an oxidative insult which decreases the antioxidant defense of the lens, particularly the vitamin C concentration. Upon oxidation, vitamin C contributes with glucose to protein glycation. It also favours tryptophan oxidation, resulting in fluorescent peptide cross-links and protein insolubilisation. The relationship between cataract and lenticular vitamin C was analysed in 48 cataractous lens nuclei classified into four severity grades, considering the sum of the colour and opacity. Ascorbic and dehydroascorbic acids were quantified by HPLC-fluorescence. The Amadori product was measured by means of furosine, advanced glycation end products by their fluorescence and tryptophan concentration by HPLC-UV. The lens vitamin C concentration significantly decreased with cataract severity, but mostly in severe brown cataracts (around 88 mumol/100 g lens in mild cataracts, and 50 mumol/100 g in dark brown lenses). The dehydroascorbic acid concentration was always low and stable (1.9 +/- 0.9 mumol/100 g), as was the furosine concentration (0.4 +/- 0.1 mumol/g). The fluorescence of insoluble advanced glycated end products was significantly higher in severe cataracts than in milder ones. The peptide tryptophan content was stable but the tryptophan to tyrosine ratio decreased and was highly correlated to the ascorbic acid concentration. Vitamin C content appears to be a good indicator of cataract severity, suggesting that oxidation could take part in cataract progression.

Ascorbic Acid↗
PubMed1997

In vitro activity of fosfomycin combined with ceftazidime, imipenem, amikacin, and ciprofloxacin against Pseudomonas aeruginosa.

The in vitro activity of fosfomycin in combination with ceftazidime, imipenem, amikacin, or ciprofloxacin was studied by an agar plate checkerboard method against 40 clinical isolates of Pseudomonas aeruginosa with various antibiotic resistance profiles. Fosfomycin/ciprofloxacin appeared to be the most effective combination (synergy 15%, addition 80%, indifference 5%), followed by fosfomycin/amikacin (synergy 7.5%, addition 52.5%, indifference 40%), fosfomycin/imipenem (addition 37%, indifference 63%), and fosfomycin/ceftazidime (addition 20%, indifference 80%). The effects of the combinations were not significantly influenced by the antibiotic susceptibility patterns of the strains.

Amikacin↗
PubMed1997

Effects of endurance training on skeletal muscle oxidative capacities with and without selenium supplementation.

The purpose of this study was to examine the changes induced by endurance training, with or without selenium (Se) supplementation on: 1) mitochondrial activity of succinate dehydrogenase (SDH) and cytochrome c oxidase (Cyt Ox),2) the myosin heavy chain (MHC) expression in muscle fibers and 3) their association with aerobic performance. Twenty-four male students volunteered to participate in this double blind study: selenium (Sel, N = 12) vs placebo (Pla, N = 12). During a 10-wk endurance training program, the Sel group received a daily Se supplementation containing 180 micrograms of organic selenium (selenomethionine), while the Pla group received a placebo. Before (Pre) and after (Post) the program (3 sessions wk-1) an endurance exercise (Capmax) was performed in order to determine the aerobic endurance capacity assessed by the total oxygen uptake during the running test (VO2tot). All parameters of aerobic performance were increased in both groups, concomitantly to a rise in mitochondrial Cyt Ox activity. Two positive relationships were found: 1) between type I MHC and VO2tot increments (r = 0.65, P < 0.05), 2) between training volumes and VO2tot increments (r = 0.53, P < 0.05; N = 23). The training program produced an 8.2% significant increase in type I MHC (P < 0.05) while type II MHC decrease was not significant (-4.4%). Although they were almost non-existent before the program, muscle fibers which co-expressed type I and II MHC displayed a marked increase afterwards (4.9 +/- 5.7 vs 1.1 +/- 2.1%, P < 0.05). Muscle GSH-Px activity, at rest, did not respond to endurance training or Se supplementation. The results suggest that the neuromuscular system is still in an evolutive state after 10 weeks of endurance training, and that selenium supplementation has no effect on endurance training-induced adaptations.

Adult↗
PubMed1997

No evidence of oxidative stress after a triathlon race in highly trained competitors.

Long distance triathlons, due to the large amounts of oxygen uptake they cause, may lead to the generation of reactive oxygen species, and consequently to oxidative stress and damage. We sought to verify this hypothesis. Twelve of the 18 male triathletes who participated in the study took part in a long distance triathlon, the others did not. The prerace blood samples were drawn 48 h before the race and repeatedly until the fourth day of recovery. The myoglobin concentrations increased immediately after the race. The concentrations of methemoglobin, disulfide glutathione (GSSG), and thiobarbituric reactive substances did not significantly change after the race. Although the race induced an inflammatory response, evidenced by the variations in neopterin concentrations and leukocyte counts, there was no consecutive oxidative stress. The basal GSH values were correlated significantly with cycling training volume (r = 0.55) and VO2max (r = 0.53). Muscle damage can occur without evidence of oxidative stress or oxidative damage. We conclude that the magnitude of the antioxidant defense system enhancement depends on training loads. Because of their training status, the triathletes did not suffer from oxidative damage after they finished the long distance triathlon race.

Adult↗
PubMed1997

[Comparative in vitro activity of cefepime: multicenter study in Aquitaine].

Over a 6 month-period (1st January to 30th June 1995), the results of antibiotic susceptibility testing routinely performed for beta-lactams against enterobacteria, Pseudomonas aeruginosa, and Acinetobacter in 7 laboratory hospitals of Aquitaine, have been collected and divided in susceptibility profiles. A total of 9269 strains (7323 enterobacteria, 1667 P. aeruginosa, 279 Acinetobacter) have been examined. On the whole, cefepime (91,5%) and ceftazidime (91,7%) were the most active cephalosporins, followed by cefpirome (87,9%) and cefotaxime (80,4%); imipenem was the most active beta-lactam agent (97,4%). When the strains were divided according to their susceptibility profiles, the advantage of cefepime was shown to be related to its excellent activity against enterobacteria: all strains susceptible to cefotaxime and ceftazidime (CTX/CAZ-S) were susceptible to cefepime, as were most of the strains with an intermediate susceptibility or resistant to these drugs (CTX/CAZ-I/R, approximately 5% of the enterobacteria). The latter strains exhibited a phenotype corresponding either to the overproduction of their chromosomal cephalosporinase (approximately 20% of the species belonging to group 3) or to the synthesis of an extended spectrum beta-lactamase (19% of the strains of Klebsiella pneumoniae). Cefepime was active against 93% of the derepressed mutants of enterobacteria, including 3 imipenem resistant isolates of Enterobacter. CAZ-S strains of P. aeruginosa (84%) were usually susceptible to cefepime (80%), as were 6% of the CAZ-I/R strains. CAZ-S strains of A. baumannii (16.3%) were generally susceptible to cefepime (83%), as were 3.2% of the CAZ-I/R strains.

Acinetobacter↗
PubMed1997

[Vaccines available in France as of 1 January 1997].

The vaccines available in France as of January 1, 1997 are listed. For each one, the nature of the vaccine, indications, efficacy, safety, contraindications, vaccinal calendar have been detailed.

Clinical Protocols↗
PubMed1996

Effects of strenuous exercise on serum myosin heavy chain fragments in male triathletes.

During the Nice Triathlon (June 26, 1994), the serum levels of type I myosin heavy chain (MHC) fragments and creatine kinase (CK and CK-MB) activities were assessed in 12 athletes in order to evaluate the exercise-induced muscle damage. Blood samples (BS) were taken 2 days before the event (baseline), on arrival, 6 and 24 h later, and 2 and 4 days later. The mean results (and SD) were respectively: MHC (microU.I-1): 142 (69), 156 (116), 242 (144), 1183 (574), 2603 (1405), 1002 (523); CK (U.I-1): 109 (27), 626 (267), 1188 (562), 1159 (442), 633 (385), 224 (119). The CK peak occurred at BS-6h for 8 subjects, and at BS-24h for the other ones. The MHC peak occurred at BS-48h in all the subjects. The CK-MB/CK ratios exhibited a profile similar to those described previously. Serum MHC peak values were correlated with CK ones (r = 0.67; p < 0.05). After a four-day recovery period, as the CK values had decreased, the MHC levels were still elevated. The main result of the study is the MHC peak occurrence at BS-48h in all the subjects.

Adult↗
PubMed1996

Validation of a micromethod for determining oxidized and reduced vitamin C in plasma by HPLC-fluorescence.

An HPLC micro-method with fluorescence detection has been developed to determine total vitamin C (vit C) and dehydroascorbic acid (DHA) concentrations in human plasma samples. This method is based on the rapid, specific reaction of DHA with dimethyl-o-phenylenediamine (DMPD) to form a fluorescent quinoxaline derivative that is quantified by HPLC in less than 5 minutes. The method was assessed with reference to the direct 2,4-dinitrophenylhydrazine (DNPH) colorimetric method. They were well correlated (r3 = 0.879), but the DMPD-HPLC method had the limit of detection 6 times lower than the standard method and the relative error for a vitamin standard was 10 times better than that of the standard method. The plasma DHA to total vit C ratio varied from 10 to 60%, depending on sample processing. Plasma that were immediately analysed contained 10% DHA whatever the subject's age; frozen deproteinized samples kept 1 week (-67 degrees C) had 20%, and blood samples kept for one hour at room temperature before treatment had up to 60% DHA. The ratio in capillary samples taken from the finger was 11-42%. This rapid, specific and very sensitive micro-method is well suited to routine measurements of plasma vit C.

Adult↗
PubMed1995

Mitochondria changes in human muscle after prolonged exercise, endurance training and selenium supplementation.

The functional and structural responses to acute exercise (E) and training, (T) with or without selenium supplementation (Sel), were investigated in a double-blind study on 24 young male subjects. The Sel or the placebo were given over 10 weeks of an endurance training programme. Prior to the programme and on its conclusion muscle biopsies were taken from the vastus lateralis muscle before and after an exhausting treadmill test of maximal endurance capacity (Capmax). The muscle samples were examined by electron microscopy to make a quantitative analysis of the mitochondria population in the muscle fibres. The number of mitochondria per area (QA) and the relative surface occupied by the total mitochondria profile area (AA) were estimated. The mean area per mitochondrion (â) was obtained by the quotient AA/QA. The effects of the isolated or combined independent variables T, E and Sel were analysed by nonparametric tests. Training induced significant increases in both QA (30%, P < 0.001) and AA (52%, P < 0.001), without changing â; T + Sel produced a slight rise of AA (27%, P < 0.001), which resulted in larger (24%, P < 0.001) â. The E produced an enlargement of â resembling swelling. This phenomenon was also found for the combinations E + T and E + T + Sel, but it was then far more pronounced in E + T. The training effects observed are in agreement with previous descriptions. In contrast, the changes observed after acute exercise seem to indicate a remarkable short-term plasticity of muscle mitochondria. The results in Sel would seem to suggest a dampening effect of the selenium on the mitochondria changes, both in chronic and acute exercise. The mechanism of this action on mitochondrial turnover is uncertain, but might be related to a higher efficiency of the selenium-dependent enzyme glutathione peroxidase.

Adult↗