Injury incidence in hip hop dance.

Hip hop dance has rapidly become a popular international art form. There is limited information on injury patterns in this population. The purpose of this study was to determine injury incidence and patterns among three groups of hip hop dancers. Three hundred and twelve intermediate, advanced, and expert hip hop dancers were recruited at battles, dance conferences, clubs, and on dance related web sites within the United States and internationally. A Web-based survey was conducted over a 6-month period. Inclusion criteria included intermediate and advanced level dancers over the age of 13. Dancers were divided into three main categories: Breakers, Popper/Lockers, and New Schoolers. Separate analysis of variances were used to compare injury pattern differences between groups. Two hundred and thirty-two dancers reported a total of 738 injuries. Five hundred and six of these (sustained by 205 dancers) were time-loss (TL) injuries. Annual injury incidence was 237% (162% involving TL). Lower extremity injuries were 52% and upper extremity injuries 32% of total injuries. Breakers had a higher injury incidence compared with Popper/Lockers, and New Schoolers. Hip hop dancers report injury rates that are higher than other dance forms but similar to gymnastics. These dancers should be educated concerning injury prevention, biomechanics, and use of protective equipment.

Reliability and validity of a new ankle electrogoniometer.

OBJECTIVES: To establish reliability, accuracy and concurrent validity of a new electrogoniometer (SG110A, Biometrics) for measuring ankle movement. METHODS: The new electrogoniometer, placed at the lateral malleolus (A-perp), was compared to a customary electrogoniometer (SG110, Biometrics), placed along the Achilles tendon (A-para). Concurrent recordings were made with motion analysis. Common dance movements were performed by 17 dancers on two days. Intraclass correlation coefficients (ICC) and standard error of measurement (SEM) were calculated for sagittal angular displacements. RESULTS: Instrument and intra-tester reliability of A-perp was high (r >or= 0.985, r >or= 0.979, respectively). Criterion and concurrent validity were also high (r >or= 0.954, r >or= 0.937). SEM ranged from 1.43 degrees to 6.99 degrees. CONCLUSIONS: The high ICC values establish acceptable reliability and validity. Subjects found A-perp more comfortable. Although both electrogoniometers are acceptable (comparable SEM) to measure extreme ankle motions, the greater comfort and durability of the new A-perp sensor is advantageous.

Reliability and validity of electrogoniometry measurement of lower extremity movement.

OBJECTIVES: To establish the reliability, accuracy and concurrent validity of electrogoniometers for measuring extreme lower extremity movements. STUDY DESIGN: Reliability, accuracy and validity study. METHODS: This project employed two experiments. Investigation I determined electrogoniometer accuracy compared to a digital protractor. Investigation II compared electrogoniometers to a criterion measure, motion analysis, in sagittal plane dance movements in 17 dancers. Intraclass correlation coefficients (ICC) and standard error of measurement (SEM) were calculated for hip, knee, and ankle sagittal plane angular displacements. RESULTS: In Investigation I, electrogoniometer to protractor correlations were high (r > or = 0.998, SEM < or =3.65 degrees ). In Investigation II, instrument and intra-rater reliability correlations were high (r > or = 0.983 and r > or = 0.972, SEM < or = 3.49 degrees and < or =4.48 degrees ), as were concurrent validity correlations (r > or = 0.949, SEM < or =6.80 degrees ) to motion analysis. CONCLUSIONS: This error may be acceptable for lower extremity studies with extreme movements when motion capture is unavailable.

Sexually dimorphic expression of oxytocin binding sites in forebrain and spinal cord of the rat.

The central actions of oxytocin on reproduction-related functions and behaviors are strongly steroid-dependent and gender specific. This study characterizes sexual differences in the oxytocin binding site expression in forebrain and spinal cord of the rat. Using film autoradiography, we quantified the density of oxytocin binding sites in the ventromedial hypothalamic nucleus, the medial and central nuclei of the amygdala, the medial bed nucleus of the stria terminalis and the spinal cord dorsal horns both in adult male and female rats, and during development. In addition, neonatal castrated males and intact neonatal females treated with a single injection of testosterone (1 mg) were examined. Data showed a sexual dimorphism in the expression of oxytocin binding sites in the spinal cord dorsal horns and in restricted areas of the forebrain that are sensitive to gonadal steroids such as the ventromedial hypothalamic nucleus, but not in gonadal steroid insensitive sites such as the central nucleus of the amygdala. Adult males had higher oxytocin binding site densities in the ventromedial hypothalamic nucleus and dorsal horns than females. In the forebrain, but not in the dorsal horn, this sexual difference required a perinatal exposure to testosterone. Neonatal castration only abolished the sexual difference in the ventromedial hypothalamic nucleus of adults, but not in the dorsal horn. Furthermore, females that received a single injection of testosterone 1 day after birth showed significant increases in the density of oxytocin binding sites in the ventromedial hypothalamic nucleus, medial nucleus of the amygdala and medial bed nucleus of the stria terminalis. In addition, the findings suggest that the sexual difference in the ventromedial hypothalamic nucleus also requires gonadal hormones in adulthood. Our data support the hypothesis that sexually dimorphic oxytocin binding sites may contribute to the regulatory central actions of oxytocin in gender specific functions and behaviors such as nociception and reproduction.

Ex vivo 12 h bactericidal activity of oral co-amoxiclav (1.125 g) against beta-lactamase-producing Haemophilus influenzae.

The aim of the study was to evaluate the in vitro/ex vivo bactericidal activity of a new coamoxiclav single-dose sachet formulation (1 g amoxicillin + 0.125 g clavulanic acid) against a beta-lactamase-producing strain of Haemophilus influenzae. The evaluation covered the 12 h period after antibiotic administration. Serum specimens from the 12 healthy volunteers included in the pharmacokinetic study were pooled by time point and in equal volumes. Eight of 12 pharmacokinetic sampling time points were included in the study. At time points 0.5, 0.75, 1, 1.5, 2.5, 5, 8 and 12 h post-dosing, the kinetics of bactericidal activity were determined for each of the serial dilutions. Each specimen was serially diluted from 1:2 to 1:256. The index of surviving bacteria (ISB) was subsequently determined for each pharmacokinetic time point. For all the serum samples, bactericidal activity was fast (3-6 h), marked (3-6 log(10) reduction in the initial inoculum) and sustained over the 12 h between-dosing interval. The results obtained also confirmed that the potency of the amoxicillin plus clavulanic acid combination was time dependent against the species under study and that the time interval over which the concentrations were greater than the MIC (t > MIC) was 100% for the strain under study. The data thus generated constitute an interesting prerequisite with a view to using co-amoxiclav 1.125 g in a bd oral regimen.

[Chronic experimental bacteremia in Yucatan micropigs]. / Bactériémie chronique expérimentale du microporc Yucatan.

The Yucatan micropig has been used to develop an experimental model of chronic bacteremia. This animal exhibits clinical and biological characteristics that are close to those in humans, and the pharmacokinetic behaviours of many classes of drugs in this model are similar to those in man. Six adult female were intravenously inoculated with a mean Escherichia coli inoculum of 5.1 x 10(9) bacteria. During five days of spontaneous evolution, the medical follow-up includes biological, clinical and bacteriological parameters. A systemic inflammatory syndrome, a sepsis, an organ insufficiency and positive blood cultures mimic the human disease. In all animals there is an adynamia, a lack of motor coordination, an anorexia, a tachypnea, a fever, a leuconeutropenia followed by an hyperleucocytosis, an anemia, a thrombopenia, an acute tubulonephritis and an elevated sedimentation rate. In some cases, there is an increase of the C reactive protein, in others, an increase of IL-6 and IL-8. At day five, all animals are alive, and five micropigs have positive blood cultures. This chronic, reproducible model is thus suitable for further antibacterial treatments evaluations.

Variable expressions of Staphylococcus aureus bicomponent leucotoxins semiquantified by competitive reverse transcription-PCR.

A competitive reverse transcription-PCR method was developed for the semiquantitation of the expression of genes encoding bicomponent leucotoxins of Staphylococcus aureus, e.g., Panton-Valentine leucocidin (lukPV), gamma-hemolysin (hlgA and hlgCB), and LukE-LukD (lukED). The optimization procedure included RNA preparation; reverse transcription; the use of various amounts of enzymes, antisense primer, and RNA; and the final amplification chain reaction. Reproducible results were obtained, with sensitivity for detection of cDNA within the range of 1 mRNA/10(4) CFU to 10(2) mRNA/CFU, depending on the gene. Both specific mRNAs were more significantly expressed at the late-exponential phase of growth. Expression was about 100-fold higher in yeast extract-Casamino Acids-pyruvate medium than in heart infusion medium. Expression of the widely distributed gamma-hemolysin locus in the NTCC 8178 strain was around 10-fold diminished compared with that in the ATCC 49775 strain. Because of the lower level of hlgA expression, the corresponding protein, which is generally not abundant in culture supernatant, should be investigated for its contribution to the leucotoxin-associated virulence. The agr, sar, and agr sar mutant strains revealed a great dependence with regard to leucotoxin expression on the global regulatory system in S. aureus, except that expression of hlgA was not affected in the agr mutant.

[Bacterial growth delay in E. coli: demonstration and evaluation of the beta-lactamase post-inhibitor effect on 6 strains with different resistance phenotypes]. / Retard de recroissance bactérienne chez E. coli: mise en évidence et évaluation d'un effet postinhibiteur de beta-lactamases sur six souches de phénotypes de résistance différents.

Six E. coli, whose phenotypes of resistance were different, were tested in vitro in order to evaluate a regrowth delay, the post beta-lactamases inhibitor effect (PLIE). This PLIE was investigated after a brief incubation in contact with clavulanic acid (CA) alone or associated with amoxicillin (AMX). After removal of the drugs used during the pre-exposure phase, the bacteria were incubated with AMX at different concentrations. The PLIE was shown not to be in association with any other regrowth delay (post-antibiotic effect or effect inherent to the technical procedures used). A PLIE was evaluated on the five intermediary or high-level beta-lactamases-producing strains. Generally, the duration of the PLIE was prolonged after the CA alone pre-exposure phase and could reach values up to 22 hours. The concentrations of AMX added in cultures previously exposed to sufficient CA concentrations were related to an extended PLIE.

Patella fractures associated with accelerated ACL rehabilitation in patients with autogenous patella tendon reconstructions.

Patella fracture is a recognized complication of ACL reconstruction with an autogenous patella tendon graft. Typically, fracture occurs as a result of a fall. The incidence of fracture is approximately 0.5%. Accelerated rehabilitation protocols can place stress on the patella, especially in the initial stages of recovery. Therapists are reminded to observe constraints placed on patients by biological tissues, recovering neuromuscular status, and previous level of conditioning. Rehabilitation protocols should be revised according to these factors.

Profile of dance injuries in a Broadway show: a discussion of issues in dance medicine epidemiology.

A description of dance injuries in a Broadway show using ballet technique is reported for the first time. Presentation of this material is used as a vehicle to discuss issues in dance epidemiology and etiology. As interest and research in dance medicine increases, standardization of reporting methods and definitions becomes critical in discussions of epidemiology and etiology. Borrowing from sports medicine classifications, which define sports injury as "time lost from play," we suggest dance injury be defined as "time lost from performing". The overall injury rate was 40.0%, which was low compared with those of classical ballet companies. The majority of injuries involved the foot and ankle, similar to previous reports of classical ballet companies. Reasons for the low injury rates and types of injuries are discussed. The information necessary to facilitate comparison of data with other studies is outlined. We hope this article will contribute to further discussion regarding adoption of universal language and details necessary for reporting injury. Additional areas of research are suggested.

Differential expression of transcripts encoding retinoid binding proteins and retinoic acid receptors during placentation of the mouse.

We report the distribution of transcripts from genes encoding the retinol binding protein (RBP), the cellular retinol binding proteins (CRBP I, II) and retinoic acid binding proteins (CRABP I, II), the retinaldehyde dehydrogenase type 2 (RALDH-2), the retinoic acid receptors (RARs), and the retinoid X receptors (RXRs) in mouse placental tissues from 6.5 to 19.5 days postcoitum (dpc). During early placentation, RBP and RALDH-2 gene expression are restricted to the endoderm of the visceral yolk sac and the outer uterine epithelium, respectively, whereas CRBP I transcripts are detected in the visceral yolk sac and in the presumptive chorioallantoic placenta. By 15.5 dpc, CRBP I expression is down-regulated in the yolk sac where CRBP II becomes strongly expressed. Expression of CRBP II is also detected in the trophoblastic giant cells. Throughout placentation, the expression patterns of the CRABP I and II genes partly overlap in the decidual tissue and the vacuolar zones of the decidua, suggesting a role for these binding proteins in sequestering free retinoic acid from maternal blood, thus regulating its availability to the embryo. RAR alpha is ubiquitously expressed in all placental tissues, except in trophoblastic giant cells, at all stages studied. During early placentation, RAR beta and RAR gamma are co-expressed in the decidua but differentially expressed in the chorionic region (RAR beta, 10.5 to 12.5 dpc) and the presumptive labyrinth (RAR gamma, 7.5 to 12.5 dpc). During the same stages, RXR alpha is strongly expressed in the presumptive placenta. RAR gamma remains weakly expressed in the labyrinth until 15.5 dpc, whereas RXR alpha exhibits a strong expression in this zone until birth, suggesting a role for these receptors in the development and function of the definitive placenta.

Characterization of a premeiotic germ cell-specific cytoplasmic protein encoded by Stra8, a novel retinoic acid-responsive gene.

The full-length cDNA corresponding to Stra8, a novel gene inducible by retinoic acid (RA) in P19 embryonal carcinoma cells, has been isolated and shown to encode a 45-kD protein. Both Stra8 mRNA and protein were induced in cells treated by all-trans and 9-cis retinoic acids. Two-dimensional gel analysis and dephosphorylation experiments revealed that the two stereoisomers of RA differentially regulate the phosphorylation status of the Stra8 protein, which was shown to exist in differently phosphorylated forms. Subcellular fractionation and immunocytochemistry studies showed that the Stra8 protein is cytoplasmic. During mouse embryogenesis, Stra8 expression was restricted to the male developing gonads, and in adult mice, the expression of Stra8 was restricted to the premeiotic germ cells. Thus, Stra8 protein may play a role in the premeiotic phase of spermatogenesis.

A new mouse member of the Wnt gene family, mWnt-8, is expressed during early embryogenesis and is ectopically induced by retinoic acid.

We have identified a novel mouse Wnt genc using a cDNA differential screening procedure for retinoic-acid-induced transcripts in P19 embryonal carcinoma cells. Sequence analysis showed that this gene represents the first murine Wnt-8 (mWnt-8) gene reported to date. The expression of the mWnt-8 gene, which is rapidly induced by retinoic acid in P19 and embryonic stem cells, appears to be restricted to early stages of mouse embryogenesis. mWnt-8 transcripts are first detected in the posterior region of the epiblast of early primitive streak-stage embryos. As gastrulation proceeds, mWnt-8 expression spreads into the embryonic ectoderm up to a sharp rostral boundary at the base of the developing headfolds. mWnt-8 is also transiently expressed in the newly formed mesoderm. mWnt-8 expression is rapidly down-regulated during early somitogenesis, the latest detectable expression domains corresponding to the presumptive fourth rhombomere and the caudal region of the neural plate. The expression pattern of mWnt-8 is clearly distinct from those of other murine Wnt genes expressed during gastrulation, but shows striking similarities with that of the chicken Cwnt-8C gene. We also show that mWnt-8 expression is ectopically induced in the rostral neural plate in response to RA exposure of presumitic (7-7.5 days post coitum) cultured mouse embryos.

Transcripts from opposite strands of gamma satellite DNA are differentially expressed during mouse development.

Using in vitro immuno-selected retinoic acid response elements, we have isolated mouse genomic clones containing major (gamma) satellite DNA repeats that are considered as typical of chromosome centromeres. Several cDNA clones were then isolated from a F9 cell cDNA library and were found to harbor variants of the 234-base pair consensus gamma satellite monomer. In Northern analysis, these satellite DNA sequences hybridized predominantly to an approximately 1.8-kb RNA species in polyadenylated RNA from P19 cells. These transcripts were strongly repressed by retinoic acid, and nuclear run-on assays revealed that this repression was, at least in part, mediated at the transcriptional level. Satellite transcripts were also detected in HeLa cells, where they were similarly down-regulated by retinoids. Heterogeneously sized satellite transcripts were detected in RNA from specific mouse tissues, such as fetuses (but not placenta), adult liver, and testis. In situ hybridization analysis revealed that satellite transcripts are generated from opposite DNA strands and are differentially expressed in cells of the developing central nervous system as well as in adult liver and testis. These data may have implications on retinoic acid-mediated transcriptional regulation and centromere function.

Psychosocial stress and NK cells among members of a communal settlement.

The aim of the present study was to assess the effect of daily psychosocial stress on the human immune system. We tested 38 couples living in a communal settlement (kibbutz) under similar economic and social conditions, sharing similar housing, nutrition and health care. They were tested repeatedly over a two year period for a number of psychosocial parameters including demoralization, social support, family cohesion, adaptational hardiness and hostility. In parallel, the natural killer "NK" cell system was analysed for distinctive markers and for cytotoxic activity. The proportion of CD16+ lymphocytes was found to correlate with cytotoxic NK activity in both men and women. In contrast, the proportion of CD57+ cells correlated with that of CD16+ cells only in women while in men only the CD57+CD8-lymphocytes subset correlated with CD16+ cells. For each individual tested, the values of NK activity and NK markers obtained in tests carried out more than a year apart showed a striking correlation. In males, NK cytotoxicity correlated with hostility but was negatively correlated with family cohesion, adaptability and hardiness. The level of CD16+ and CD57+ cells correlated positively with demoralization in males only. Changes in the level of NK activity and in the level of CD16+ cells occurring in husbands during the observation period correlated positively with changes in demoralization and negatively with changes in family cohesion and adaptability. The results indicate that daily psychological stress and low family function may enhance the NK system, and that this response may differ between the sexes.

Determinants of physical ability in 7th grade schoolchildren.

The aim of the study was to determine factors associated with running time in children aged 12 years, according to sex and sexual maturation of girls. The physical ability was measured, using a 1000 meter run in a group of 942 boys and girls aged 12. In addition, data was collected on family sports activities and the children's sports activities, using questionnaires for parents and children. Before the 1000 meter run, physical examination was carried out. Nutrition habits of the family in the home and outside were self-reported in a questionnaire. The mean time for run in boys was shorter by 40 seconds than that for girls. Premenarche girls ran significantly faster than postmenarche girls (p less than 0.05). The best predictors for short running time were triceps skinfold thickness and sport motivation of the children. Weaker correlation was observed between food variables, family characteristics and running time. The highest prediction of running time by the measured variables was found for postmenarche girls, explained by the high correlation of running time with the behavioral variables. In boys and premenarche girls, the best predictors for running time were the physical and physiological characteristics of the children.

The influence of a physical ability intervention program on improved running time and increased sport motivation among Jerusalem schoolchildren.

Several studies have demonstrated an inverse relationship between physical activity and coronary heart disease (CHD). Other studies have reported a negative correlation between aerobic capacity and obesity and CHD risk factors among adolescents. In this study, the possibility of modifying physical ability in adolescents aged 13 has been examined through a physical ability intervention program. During 1984-1985, all eligible eighth graders from five Jerusalem public schools participated in the program. Physical ability was defined in the biological dimension by the running time for 1000 meters, and in the psychological dimension by sport motivation. The intervention program involved a periodic and progressive increase of physical effort of children in 16 gym lessons during the regular curriculum. The major findings were that the test group improved their running time and had better sport motivation than did the control group, and there were differences between boys and girls and an influence of sexual maturation on running time in girls.

Determinants of blood pressure in 7th grade Jerusalem school children.

The determinants of blood pressure level were analyzed in a group of 1154 Jerusalem school children aged 12. After controlling for age, significant differences in blood pressure measurements were found between three groups: boys, pre-menarche girls and post-menarche girls. A comparison of the means of selected biological variables showed that girls who have reached menarche have levels of systolic blood pressure, weight, height and Quetelet's index higher than boys and pre-menarche girls. However, levels of triceps skinfold thickness and pulse rate were similar in the two groups of girls and higher than in boys. Using multiple regression analysis, we found that much of the variance (boys 29%, post-menarche girls 21% and pre-menarche girls 15%) of systolic blood pressure could be explained by a combination of biological variables (Quetelet, pulse rate, triceps skinfold thickness and height) while these variables explained a much smaller proportion (boys 12%, post-menarche girls 17% and pre-menarche 9%) of diastolic blood pressure variance. The predictive power of systolic blood pressure by the measured biological variables was higher in boys than in girls. However, diastolic blood pressure was better predicted by the biological variables in the group of girls with menarche than in other groups. Elevated blood pressure was observed in 3.2% of the examined children. High values for Quetelet's index were observed in 6.4%. The prevalence of elevated measurements of blood pressure and Quetelet's index were significantly higher in girls with menarche. Among children aged 12, the association between sociodemographic characteristics and blood pressure level was weak, as measured in multiple regression analysis.