EGSnrc calculation of activity calibration factors for the Vinten ionization chamber

The National Physical Laboratory Vinten 671 chamber was selected as a proving ground for a new radionuclide source model in the EGSnrc software. The computational Vinten model is validated against measurements of radionuclide artifacts whose activities were determined by absolute methods. The response of the Vinten chamber is first calculated as a function of gamma energy, but more strikingly, an explicit simulation of radionuclide decay was implemented and now permits the direct determination of a calibration factor, including additional effects due to all decay paths of the radionuclide. The Monte Carlo and experimental calibration factors are found to agree at the percent level, in absolute terms.

Agreement between survey data and Régie de l'assurance maladie du Québec (RAMQ) data with respect to the diagnosis of asthma and medical services use for asthma in children

Introduction

The goal of this study was to assess the agreement between the results of a respiratory health survey conducted in Montréal on children aged 6 months to 12 years and the Régie de l'assurance maladie du Québec (RAMQ, Quebec health insurance board) database in terms of the diagnosis of asthma and medical services use. A secondary aim was to evaluate the effect of the survey method used (Internet-based survey or telephone survey).

Methods

We assessed whether a diagnosis of asthma was made for 7922 children. In addition, we compared the use of medical services for asthma (emergency department visits and hospitalizations) in the 12 months preceding the survey for the 402 children considered to have asthma, using 2 groups of respiratory diagnoses and 2 data linkage periods. The agreement between the 2 data sources was evaluated using the kappa statistic (κ) and sensitivity and specificity, as well as percentages of agreement, overreporting and under-reporting with respect to health services use.

Results

Moderate agreement was found between the 2 data sources (survey and RAMQ data) in terms of the diagnosis of asthma (κ = 0.54 and κ = 0.60 depending on the definition used). Specificity was high (93% and 96%), but sensitivity varied (50% and 65%). Respondents over-reported health services use, resulting in moderate kappa values (0.49 for emergency department visits and 0.48 for hospitalizations). However, when more diagnoses were included in the definition and when the linkage period was extended (15 rather than 12 months), the kappa values increased (0.59 for emergency department visits and 0.64 for hospitalizations) and sensitivity and specificity were high. Slightly higher agreement was obtained for the Internet-based survey relative to the telephone survey.

Conclusion

The findings validate the use of survey data with respect to the diagnosis of pediatric asthma and major health services use for this disease.

Agreement between survey data and Régie de l'assurance maladie du Québec (RAMQ) data with respect to the diagnosis of asthma and medical services use for asthma in children

INTRODUCTION

The goal of this study was to assess the agreement between the results of a respiratory health survey conducted in Montréal on children aged 6 months to 12 years and the Régie de l'assurance maladie du Québec (RAMQ, Quebec health insurance board) database in terms of the diagnosis of asthma and medical services use. A secondary aim was to evaluate the effect of the survey method used (Internet-based survey or telephone survey).

METHODS

We assessed whether a diagnosis of asthma was made for 7922 children. In addition, we compared the use of medical services for asthma (emergency department visits and hospitalizations) in the 12 months preceding the survey for the 402 children considered to have asthma, using 2 groups of respiratory diagnoses and 2 data linkage periods. The agreement between the 2 data sources was evaluated using the kappa statistic (κ) and sensitivity and specificity, as well as percentages of agreement, overreporting and under-reporting with respect to health services use.

RESULTS

Moderate agreement was found between the 2 data sources (survey and RAMQ data) in terms of the diagnosis of asthma (κ = 0.54 and κ = 0.60 depending on the definition used). Specificity was high (93% and 96%), but sensitivity varied (50% and 65%). Respondents over-reported health services use, resulting in moderate kappa values (0.49 for emergency department visits and 0.48 for hospitalizations). However, when more diagnoses were included in the definition and when the linkage period was extended (15 rather than 12 months), the kappa values increased (0.59 for emergency department visits and 0.64 for hospitalizations) and sensitivity and specificity were high. Slightly higher agreement was obtained for the Internet-based survey relative to the telephone survey.

CONCLUSION

The findings validate the use of survey data with respect to the diagnosis of pediatric asthma and major health services use for this disease.

A flavonoid fraction purified from Rutaceae aurantiae (Daflon(R)) inhibiting AGE formation, reduces urinary albumin clearance and corrects hypoalbuminemia in normotensive and hypertensive diabetic rats

AIM

Advanced glycation endproducts (AGEs) have been shown to contribute to alteration of glomerular permselectivity to proteins in diabetes. Oxidative stress is required for AGE formation. Therefore we studied the effect of an antioxidant micronized purified flavonoid fraction (MPFF, Daflon(R) 500 mg), on urinary albumin clearance in diabetic rats.

METHODS

Hyperglycaemia was induced by streptozotocin 55 mg/kg IM at days 0 and 7 in normotensive Wistar rats (NWR, diabetes duration 5 months) or hypertensive Wistar Kyoto rats (SHR, diabetes duration 2 months). MPFF was administered at 300 mg/kg/day, from day -2 until sacrifice.

RESULTS

After 5 months of diabetes in NWR, MPFF reduced albumin clearance from 729±92 to 392±60 nl/min/kg, p<0.01, and restored albuminemia from 20.4±0.9 to 24.0±1 g/l, p<0.05; albumin fractional clearance was significantly diminished in the flavonoid-treated diabetic rats (0.360±0.037‰ versus 1.335±0.430‰ in the diabetic controls, p<0.001); MPFF did not significantly modify blood glucose and plasma fructosamine levels. After 2 months of diabetes in SHR, MPFF reduced albumin clearance from 243±121 to 101±47 nl/min/kg, p<0.05, and restored albuminemia from 21.1±1.6 to 26.7±2.2 g/l (p<0.05); MPFF also decreased plasma fluorescence characteristic of AGEs (p<0.02). Besides hesperetin, a main metabolite of MPFF recovered in plasma, inhibited in vitro the formation of the crosslinking AGE pentosidine in collagen incubated with high glucose (p<0.001).

CONCLUSION

Our results confirm the role of glycoxidative stress in diabetic nephropathy. MPFF might be useful as complementary treatment for preventing diabetic microangiopathy.

Preparation and Characterization of New Molybdenum Nitride or Oxynitride Phases

Several methods of synthesizing molybdenum nitride or oxynitride fine powders are presented.

We have prepared a γ-Mo2N type oxynitride phase by reacting ammonia with MoO3. The surface area and morphology of the oxynitride powders depend on the synthesis conditions. Characterization of the solids by elemental analysis, X-ray and neutron diffraction, and thermogravimetric analysis shows dramatic modification of the stoichiometry of conventional Mo2N nitride. Aging at room temperature under air results in decreasing the material surface area. The initial surface area can be recovered be fine tuning of experimental conditions. MoCl5 and Ca3N2 are reacted in a molten CaCl2 medium leading to a new Mo2N structure type.

The reaction between molybdenum sulfide and NH3 produces two different phases depending on the reaction conditions. They are structurally related to δ-MoN.

An exactly solvable Ogston model of gel electrophoresis: VIII. Nonconducting gel fibers, curved field lines, and the Nernst-Einstein relation

In this article, we examine the low-field electrophoretic migration of infinitely small analytes in dilute sieving media made of nonconducting gel fibers. Using an Ogston obstruction model, we show that the electrophoretic mobility is not affected by the presence of curved field lines. In other words, the Nernst-Einstein relation between the mobility and the diffusion coefficient is valid regardless of the electrical properties of the gel fibers. Although this finding may greatly simplify the development of obstruction models of electrophoretic sieving, it also represents a critical test for any analytical or computational approach.

Associations of age, smoking habits and diabetes with plasma vitamin C of elderly of the POLA study

The objective of this study was to determine the associations of age and sex with plasma vitamin C (vit C) concentration taking into account smoking habits and the presence of age-related pathologies, such as diabetes. The POLA study is a population-based study on age-related eye diseases and their risk factors, and plasma Vitamin C evaluation is part of the biological parameters measured in the 1987 volunteer subjects living in Sète (South of France) and aged more than 60 years. Men had lower average plasma vit C levels than women (31.6 microM.L-1 versus 40.3 microM.L-1, p = 0.001). Plasma vit C was stable as a function of age in women but decreased in men (p = 0.02), enhancing the difference in vit C concentration between men and women with advancing age. Smoking more than 10 cigarettes a day was associated to a lower plasma vit C concentration in men (p = 0.001) but not in women, and diabetic subjects tended to have lower vit C concentrations, the difference being significant only in women (p = 0.003). We conclude that there is a clear influence of sex on plasma vit C. This difference may be due to dietary habits, or metabolism, but may also be due to different sensitivity of age, smoking and to some pathologies.

Theory of DNA electrophoresis: a look at some current challenges

Although electrophoresis is one of the basic methods of the modern molecular biology laboratory, new ideas are being suggested at an accelerated rate, in large part because of the pressing demands of the biomedical community. Although we now have, at least for some methods, a fairly good theoretical understanding of the physical mechanisms that lead to the observed peak spacings, widths and shapes, this knowledge is often too qualitative to be used to guide further technical developments and improvements. In this article, we review some selected elements of the current state of our theoretical ignorance, focusing mostly on DNA electrophoresis, and we offer several suggestions for further theoretical investigations.

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.

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.

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.

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.

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.

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.

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.

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.

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.

[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.

[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.

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.

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.

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.

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.

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.

Expression of the hepatic insulin receptor gene in the rat during postnatal development

Changes in the expression of the liver insulin receptor are known to occur in the rat during postnatal development. To assess whether such changes occur at the level of gene expression, steady-state levels of insulin receptor mRNA and transcription rates of the receptor gene have been measured in livers of rats from birth (1 day) to adulthood (60 days). Northern blot analysis of liver RNA revealed two major insulin receptor mRNA species of 9.5 and 7.5 kb. When normalized to beta actin mRNA, insulin receptor mRNA levels increased 4-fold between 1 and 15 days, remained stable between 15 and 30 days, and decreased 2-fold between 30 and 60 days. These changes were fully suppressed by in vivo treatment with actinomycin D, an inhibitor of gene transcription. In vitro nuclear transcription assays showed that the rate of transcription of the insulin receptor gene increased 2-fold between 1 and 30 days. Insulin receptor concentration in liver membrane fractions did not exactly parallel insulin receptor mRNA levels since it increased by 20-30% from 1 to 10 days and decreased 2-fold from 10 to 60 days. During the suckling-weaning transition, insulin receptor mRNA level decreased 2-fold in rats weaned onto a high carbohydrate diet but remained unchanged in rats weaned onto a high fat diet. Throughout postnatal life, an inverse relationship was observed between liver insulin receptor mRNA and plasma insulin levels. These results show that transcriptional changes in insulin receptor gene expression occur postnatally and suggest that such changes may be insulin-related.

Selenium and training effects on the glutathione system and aerobic performance

Changes in blood glutathione antioxidant system in response to exercise and training, and aerobic performance, were investigated. Selenium (Se) supplementation effects on these changes were evaluated. The study was double blind. Both groups selenium (Sel, N = 12) and placebo (Pla, N = 12), followed a 10-wk endurance training program, with a prolonged exhaustive exercise bout performed (Cap Max), before (Pre) and after (Post) training. Blood was sampled before (Bef) and after (Aft) Cap Max. The oxidation of blood glutathione after Cap Max exercise showed a reactive oxygen species production. Training developed maximal aerobic power and capacity, significantly increased (P < 0.001) plasma and erythrocyte glutathione peroxidase (GPx) activity, and decreased (P < 0.001) erythrocyte glutathione reductase activity. The Se supplementation caused an increase in the basal plasma GPx level (P < 0.05). There was also a correlation (r = 0.66, P < 0.05) between the variation in VO2max and that of erythrocyte GPx only in supplemented subjects. Our results confirm that blood glutathione remains a sensitive marker of oxidative stress induced by exhausting submaximal exercise and that the antioxidant potential of GPx can be developed by endurance training. Se supplementation at the dose used had no effect on physical performance.

Muscle GSH-Px activity after prolonged exercise, training, and selenium supplementation

A double-blind study of the effects of supplementing with selenium vs. placebo on the physiological responses to acute and chronic exercise was conducted in 24 healthy, nonsmoking males, mean age 22.9 +/- 2.1 yr, randomly divided into two groups of 12 (Pla/Sel). After a controlled period in the absence of training, all subjects were put on an individualized endurance training program with the same rules of progression and overload (3 sessions/wk x 10 wk). Supplementation, either real (240 micrograms of organic selenium/d in Sel group) or imaginary (Pla group) was administered during the same period. In each of the conditions Pre- and Post- (training +/- sel supplementation), muscle, plasma, and systemic parameters were determined before (BF) and after (AF) acute exercise, involving the repetition of muscle work cycles separated by 5-min recovery periods, combining 20 min at 65% and a maximal duration of 100% VO2 max of running on a treadmill, leading the subjects to exhaustion between 2 h 40 min and 3 h 30 min. Changes in parameters as a function of three independent variables: 1. Acute exercise (E); 2. Chronic exercise (T); and 3. Selenium supplementing (S) were tested with ANOVA and the Student's t-test on paired series. Among the variables examined, muscle glutathione peroxidase (GPx) presented a remarkable behavior.(ABSTRACT TRUNCATED AT 250 WORDS)

[Rheumatoid polyarthritis, Gougerot-Sjögren syndrome and chronic myeloid leukemia. Apropos of 2 cases]

Two cases of rheumatoid arthritis with Sjögren's syndrome are reported which developed chronic myelocytic leukemia. The relationships between these illnesses, rheumatoid arthritis and Sjögren's syndrome on the one hand, and a myeloproliferative disorder on the other hand, are discussed, as well as the possible role of the treatment regimens (synoviorthesis with radio-isotopes in case number 1). The possibility that this association came about by pure coincidence can not be excluded due to the exceptional character of these illnesses.

[Determination of fetal infectious risk by bacteriological examination of the amniotic fluid after premature rupture of the membranes]

Amniotic fluid was obtained per vagina from 228 mothers with premature rupture of the membranes and examined bacteriologically. The aim was to assess the importance of amniotic fluid contamination and the risk of foetal infection in the absence of systematic antibiotic therapy in the mothers. The incidence of amniotic fluid contamination was apparently greater in those mothers who had received antibiotics although the proportion of neonates with a true infection (3%) was almost identical. The absence of selection of resistant organisms is indicated by the marked preponderance of streptococci and the scarcity of Gram negative enterobacteriacae. Thus it is reasonable not to give systemic antibiotics but to culture the amniotic fluid. Infection can then be anticipated and in affected neonates the appropriate therapy started immediately.

[Spontaneous bacteriological course of prolonged rupture of the fetal membranes (author's transl)]

Bacteriologic study of amniotic fluid was undertaken in 300 cases of prolonged rupture of the membranes to evaluate the risk of infection without systematic administration of prophylactic antibiotics to the mother. The rate of amniotic contamination was 8.3 per cent within the first 12 hours following rupture of the membranes, it increased with time to reach 52 per cent, after 48 hours. In 90 per cent of the cases, contamination was caused by streptococci and anaerobes, Streptococcus B alone being responsible for 50% of the contaminations. Antibiotics administered to the mother were effective, but they needed a 6 hour-minimum delay to sterilize a contaminated amniotic fluid. Although the overall percentage of contamination was 23 per cent, infection occurred in only 4 per cent of the infants. The outcome was satisfactory in every case. Those results do not seem to discredit the suppression of prophylactic cover antibiotic therapy following the premature rupture of the membranes.

[Risk of neonatal Streptococcus B infection]

23 cases of contamination with streptococcus group B have been seen after premature rupture of the membranes. Mothers and fetuses have been affected. The systematic study of swabs or liquor or cervical discharge carried out on the mother since the time her membranes had ruptured show that in 74 per cent of cases studied contamination existed within the first 24 hours. Giving antibiotics to the mother before delivery gave very variable results. These multiple tests, before and around the time of birth, made it possible to detect the children at risk of infection and to start antibiotic therapy with a narrow spectrum antibiotic of the type Penicillin G. The clinical progress of these children, which is usually favourable, gives no reason for postponing prophylactic cover antibiotic treatment when the membranes have ruptured prematurely.

[Infections during malignant blood diseases. Value of the carbenicillin-gentamicin combination]

The association of carbenicillin and gentamicin was used as a routine in the early treatment of 48 attacks of fever, in 38 patients who mostly had acute leukemia and marrow aplasia. The attacks of infection may be classified as follows: 30% septicemia, 30% local infections, 40% no bacteria were identified. Among the septicemias, we noted 5 septicemias due to pyocyaneus, 4 due to klebsiella. On the whole, in the attacks of fever, the association of carbenicillin and gentamicin proved effective in 70% of cases, but a cure was obtained in only 56% of cases. In vitro, the association carbenicillin-gentamicin proved justified in 70% of cases. There was no special intolerance, apart from a few cases of hypokalemic alkalosis. The association carbenicillin-gentamicin, by its broad spectrum and especially in view of its elective effect on the pyocyaneus is an excellent initial form of antibiotic therapy, when faced with infection in a patient with malignant blood disease. However, it should be recognised that the efficacy of this association depends on the number of circulating polynuclear cells and that some bacteria, such as the klebsiella, are clear cells and that some bacteria, such as the klebsiella, are often resistant to this antibiotic association.