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Biomedical subjects

A Claessens

Publications and source records attributed to A Claessens.

12 recordsLinked to original sources
PubMed2001

Tracking of physical fitness during adolescence: a panel study in boys.

PURPOSE: To investigate the tracking in physical fitness (PF) viewed as a whole, a multidimensional trait of the subject, and to establish the stability of each factor of PF in adolescence from the perspective of a panel study using the structural equation modeling approach. METHODS: From a sample of 454 boys followed from 12 to 18 yr of age of the Leuven Growth Study, we considered only three consecutive measurement occasions with a mean age of 12.76, 14.69, and 17.73 yr. Physical fitness was evaluated by means of a battery composed of the following tests: plate tapping, sit and reach, vertical jump, arm pull, leg lifts, bent arm hang, and shuttle run. Structural equation models were fitted to the data, namely autoregressive models with latent variables. These models were used to quantify the tracking of PF as a whole and also of the individual marker variables of fitness. RESULTS: Stability estimates of PF as a whole are rather high, beta21 = 0.86 and beta32 = 0.68, with an explained variance of 74% and 73%, respectively. Tracking coefficients represented by disattenuated autocorrelations among the fitness factor gave high results: r1,2 = 0.86; r1,3 = 0.78; and r2,3 = 0.85. CONCLUSIONS: Physical fitness as a whole is highly stable in adolescent years and very predictable from early years. The same is observed for each factor of fitness. Moreover, autoregressive models within the context of structural equation modeling are better suited than simple Pearson or Spearman autocorrelations to study the tracking problem of PF.

Adolescent↗
PubMed2001

Bone mass and lifetime physical activity in Flemish males: a 27-year follow-up study.

PURPOSE: The present population study is conducted to examine the extent to which lifetime physical activity and lifestyle parameters contribute to bone mass. METHODS: The design of the project is a 27-yr prospective follow-up study. Subjects are 126 males gathered from the Leuven Longitudinal Study on Lifestyle, Physical Fitness and Health, and aged 13 yr at the onset of the study and 40 at the end of the follow-up. Physical activity and lifestyle parameters are obtained with questionnaires. Bone mass is measured by means of dual-energy x-ray absorptiometry (DXA). RESULTS: Results from correlation and regression analyses show that the body mass index (BMI) is the most important parameter in relation to cortical and trabecular bone mass at every examination period. Longitudinally, static arm strength, running speed, and upper muscular endurance contribute significantly to the prediction of adult bone mass. The parameter "change in motor fitness" between 18 and 13 yr old was used to control for hereditary influences. The score for static arm strength and trunk muscle strength demonstrates a significant correlation with adult total bone mineral content (BMC) and lumbar bone mineral density (BMD), respectively. At the age of 40, the Baecke sports index is almost equally important as BMI in explaining the variance in BMD, and static arm strength is the most important parameter (after BMI) for BMC. CONCLUSION: Lifetime physical activity, physical fitness, and BMI all contribute to adult bone mass. The clinical relevance of these findings is emphasized by the fact that the observed patterns of physical activity and motor fitness pertain to customary lifestyle and are thus feasible targets.

Adolescent↗
PubMed1997

A prospective follow-up study of 5669 users of lansoprazole in daily practice.

BACKGROUND: Immediately after the introduction of the proton pump inhibitor lansoprazole, a 2-year follow-up study was started to evaluate patterns of use, safety and effectiveness of this drug in naturally occurring groups of patients in the Netherlands. Medical data were recorded by participating physicians while medication listing were provided by pharmacists. METHODS: The study was designed according to the Safety Assessment of Marketed Medicines guidelines. The only inclusion criterion was the use of lansoprazole prior to entry into the study. RESULTS: A total of 5669 lansoprazole users was included by 374 general practitioners and 117 specialists. Lansoprazole was mostly prescribed in patients with reflux oesophagitis (55.1%), 'gastritis' (26.8%) and duodenal ulcers (11.4%), sometimes as part of a Helicobacter pylori eradication therapy (8.5%). For their complaints most patients (91.1%) had previously used acid-related drugs. Improvement or disappearance of complaints was achieved in 88.9% and 90.5% of patients after 4 and 8 weeks of treatment, respectively. Diarrhoea (4.1%), headache (2.9%) and nausea (2.6%) were the most frequently reported adverse events. CONCLUSION: The patterns of use of lansoprazole in daily practice deviated from the recommendations in the information leaflet. Nevertheless, lansoprazole was found to be safe in this naturally occurring group of users. Effectiveness appeared to be comparable to results found in clinical trials of the registered indications for lansoprazole.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed1996

Soluble form of Lamp II in purified rat liver lysosomes.

Lamp II (for lysosomal associated membrane protein II) is an integral type I glycoprotein. It consists of a very large and heavily glycosylated luminal domain, a single transmembrane segment, and a short cytoplasmic tail. We show that in highly purified lysosomes from rat liver, Lamp II, immunodetected with a monoclonal antibody on Western blots, it surprisingly distributed between a membrane bound form and a "soluble" form. The partition of the protein between the membrane and the content of lysosomes is strongly pH dependent. The soluble Lamp II population is sensitive to pH dependent aggregation as it is for many lysosomal content enzymes.

Animals↗
PubMed1993

Gymnast wrist.

Excessive or repetitive loading of an immature joint can lead to premature closure of the growth plate. In gymnastics this event is known as the gymnast wrist, or the Madelung-like deformity. Six new cases are presented. All had an ulnar-plus variance and an increased sagittal angle of the distal radial epiphysis. Five of them preferred to stop their sports career one was successfully treated with an arthroscopic debridement of the TFCC.

Adolescent↗
PubMedDate not supplied

Skeletal maturity and socio-economic status in Portuguese children and youths: the Madeira growth study.

BACKGROUND: Skeletal maturity is used to evaluate biological maturity status. Information about the association between socio-economic status (SES) and skeletal maturity is limited in Portugal. AIMS: The aim of this study is to document the skeletal maturity of youths in Madeira and to evaluate variation in maturity associated with SES. SUBJECTS AND METHODS: The study involved 507 subjects (256 boys and 251 girls) from the Madeira Growth Study, a mixed-longitudinal study of five cohorts (8, 10, 12, 14 and 16 years of age) followed at yearly intervals over 3 years (1996-1998). A total of 1493 observations were made. Skeletal age was estimated from radiographs of the hand and wrist using the Tanner-Whitehouse 2 method (TW2). Social class rankings were based on method. Five social rankings were subsequently grouped into three SES categories: high, average and low. RESULTS: Median for the radius, ulna and short finger bones (RUS scores) in the total sample of boys and girls increased curvilinearly across age whereas median for the 7 (without pisiform) carpal bones (Carpal scores) increased almost linearly. The 20-bone maturity scores demonstrated distinctive trends by gender: the medians for boys increased almost linearly while the medians for girls increased curvilinearly. SES differences were minimal. Only among children aged 10-11 years were high SES boys and girls advanced in skeletal maturity. Madeira adolescents were advanced in skeletal maturity compared with Belgian reference values. CONCLUSION: The data suggests population variation in TW2 estimates of skeletal maturation. Skeletal maturity was not related to SES in youths from Madeira.

Adolescent↗
PubMedDate not supplied

Stability of anthroposcopic and anthropometric estimates of physique in Belgian boys followed longitudinally from 13 to 18 years of age.

The stability of physique determined by the anthroposcopic 'Atlas' technique and the anthropometric Health-Carter method was examined in a sample of 210 healthy Belgian schoolboys studied longitudinally at yearly intervals from 13 to 18 years of age. The two rating systems were also compared. Results indicate that components of the same type in the two methods do not measure the same underlying factors, particularly for mesomorphy (anthroposcopic technique) and the second component (Health-Carter method). The methods cannot be considered as equivalent. The stability analysis reveals that the 'athletic' component tends to be less stable than the other two components, especially in the anthroposcopic Sheldon technique. In general, however, the constancy of the three somatotype components is fairly high during the growth period considered.

Adolescent↗
PubMedDate not supplied

Skeletal maturity and body size of teenage Belgian track and field athletes.

Attained skeletal maturity (TW2 RUS method), skeletal maturity relative to chronological age, and body size of national-level Belgian track and field athletes 15 to 18 years of age were considered. Among the 47 male athletes, 29 (62%) were skeletally mature, while 15 (52%) of the 29 female athletes were skeletally mature. There appeared to be a predominance of skeletally mature individuals among male sprinters and jumpers, while a majority of female sprinters were not skeletally mature. Both skeletally mature and immature individuals were rather evenly represented in the other track and field categories, with the exception of female throwers, who were skeletally mature. Mean statures and weights of skeletally mature and immature 16-, 17-and 18-year-old male athletes did not differ significantly, though the skeletally mature tended to be heavier. In contrast, the skeletally mature female athletes, on the average, were taller and heavier than the skeletally immature, although the differences among the small groups were not statistically significant.

Adolescent↗
PubMedDate not supplied

Motor performance during adolescence and age thirty as related to age at peak height velocity.

Relationships between motor performance, as measured by various fitness tests, and age at peak height velocity have been studied in a sample of 173 Flemish boys, measured yearly between +/- 13 and +/- 18 years and again as adults at 30 years of age. In addition to correlation studies, comparisons were made between boys with an early, average and late age at peak height velocity. To summarize the successive measurements during adolescence, a longitudinal principal component analysis was carried out. The first component can be interpreted as an average percentile level component. During adolescence, three performance tasks, namely speed of limb movement, explosive strength and static strength, are negatively related to age at peak height velocity; thus early maturers performed significantly better than late maturers. However, between late adolescence and adulthood, a cross-over of the average distance curves between 18 and 30 years of age was noted for almost all motor tasks. The late maturers not only caught up the early maturers, but there were significant differences for explosive strength and functional strength in favour of late maturers. In order to predict performance in adulthood from measures during adolescence, the following hypothesis is suggested: the best results at adulthood are obtained by those men who were already good performers during adolescence and who were late maturers, while the worst results are obtained by poor performers during adolescence who were early maturers.

Adolescent↗
PubMedDate not supplied

Gymnast wrist: an epidemiologic survey of ulnar variance and stress changes of the radial physis in elite female gymnasts.

The ulnar variance in female gymnasts attending the World Championship Artistic Gymnastics Rotterdam 1987 was measured. There was a marked increase in the ulnar length in adult as well as immature gymnast compared with nonathletes. The changes in relative ulnar length were correlated to weight, height, and skeletal age of the athletes. In 10% of the gymnasts' wrists we noted so-called "stress-related changes" of the distal physis of the radius. Repetitive injury and compression of the wrist leads to a premature closure of the distal radial growth plate resulting in secondary ulnar overgrowth.

Adolescent↗