Effects of vibration on flexibility: a meta-analysis.

Exogenous stimulation of skeletal muscle or tendon is often used to improve range of motion. Despite substantial research efforts, however, the effects of vibration on flexibility have not been clarified. In this review, we investigated the effects of acute and chronic intervention programs which used vibration to improve flexibility in young healthy individuals. Effect size was calculated using data from a total of 600 participants in 19 studies before and after the introduction of vibration-based intervention, and a total of 324 participants in 13 studies on the additive effects of vibration compared with the identical conditions without vibration. Sub-group analyses were performed based on intervention period, type of exercise, and type of vibration. Meta-analysis showed that vibration interventions had significant effects on flexibility (standardized mean difference [SMD]=-0.79, 95% confidence interval [CI]=-1.14- -0.43; p<0.001), albeit with the possibility of heterogeneity (I(2)=75%). Another meta-analysis revealed a significant additive effect of vibration on flexibility compared with the identical condition without vibration (SMD=0.25, 95%CI=0.03-0.48; P=0.03), with small heterogeneity (I(2)=0%). The risk of publication bias was low judged from Kendall's τ statistic. We concluded that the use of vibration might lead to additive improvements in flexibility.

The effects of whole-body vibration on muscle strength and power: a meta-analysis.

Exercise with whole-body vibration (WBV) is becoming popular as an alternative to conventional training or as supplementary training. However, despite increasing research efforts in this field, additive effects of WBV on muscle performance remain unclarified. In this review, we investigated the additive effects of long-term WBV on muscle strength and power. This meta-analysis was restricted to randomized controlled trials lasting for at least 5 weeks comparing exercise with and without WBV, or comparing only WBV exposure and control. Data from a total of 314 participants in 10 studies on knee extension muscle strength, and 249 participants in 7 studies on countermovement jump height were pooled using random-effect models. Meta-analysis showed significant additional effects of WBV on muscle strength (standardized mean difference [SMD]=0.76, 95% confidence interval [CI]=0.21-1.32; p=0.007) and countermovement jump (SMD=0.87, 95% CI=0.29-1.46; p=0.003). Based on these findings, we concluded that the use of WBV would lead to greater improvements in both knee extension muscle strength and countermovement jump than under identical conditions without WBV.

Effects of resistance training with whole-body vibration on muscle fitness in untrained adults.

The effects of resistance training (RT) combined with whole-body vibration (WBV) on muscle fitness, particularly muscle hypertrophy and neuromuscular performance, are not well understood. We investigated the effects of WBV in healthy, untrained participants after a 13-week RT course by performing magnetic resonance imaging and by measuring maximal isometric (with electromyography) and isokinetic knee extension strengths, isometric lumbar extension torque, countermovement-jump, knee extension endurance, and sit-ups. Thirty-two individuals (22-49 years old) were randomly assigned to RT groups with (RT-WBV, n=16) or without WBV (RT, n=16). Following the RT course, significantly higher increases in the cross-sectional areas of m. psoas major (vs baseline values) and erector spinae muscle (vs the RT group) were observed in the RT-WBV group (+10.7%, P<0.05; +8.7%, P<0.05) compared with the RT group (+3.8%, P=0.045; 0.0%). Higher increases from baseline were also observed in maximal isometric force, concentric knee extension torque, countermovement-jump, and maximal isometric lumbar extension torque in RT-WBV (+63.5%; +76.7%, +15.0%, and +51.5%, respectively; P<0.05) than in those of RT (+25.6%, P=0.001; +17.8%, P=0.18; +11.3%, P=0.001; and +26.4%, P<0.001, respectively). The WBV-induced increases in muscle hypertrophy and isometric lumbar extension torque suggest a potential benefit of incorporating WBV into slow-velocity RT programs involving exercises of long duration.

Physical activity, body weight, and pancreatic cancer mortality.

In a study of 32 687 subjects with data on physical activity and body mass index (BMI) collected serially over time, we examined associations with pancreatic cancer mortality (n=212). Despite plausible biologic mechanisms, neither physical activity (multivariate relative risks for increasing levels: 1.00, 0.98, 0.92, and 1.31, respectively) nor BMI (corresponding findings: 1.00, 0.84, 1.08, and 0.99, respectively) significantly predicted pancreatic cancer mortality.

Physical activity and all cause mortality in women: a review of the evidence.

A computer assisted literature search was performed (Medline, 1966-2000) to examine the association of physical activity with all cause mortality in women. It was concluded that, by adhering to current guidelines for physical activity and expending about 4200 kJ of energy a week, women can postpone mortality. The magnitude of benefit experienced by women is similar to that seen in men.

Fortuitously discovered persistent left superior vena cava in young competitive athletes. Clinical implications of sports physicians.

This report describes two athletes with persistent left superior vena cava (PLSVC) accidentally identified during preparticipation medical evaluation. The clinical implications of PLSVC for sports physicians are also discussed. A 16-year-old male ice hockey player and an 18-year-old male high-level field hockey player visited our institute for medical evaluation prior to participating in competition. Neither complained of palpitation, faintness or syncope, which would have suggested a possible cardiac rhythm disturbance, or had been informed of any abnormalities in previous physical examinations. Nonetheless, echocardiography revealed dilated coronary sinuses, and venography confirmed PLSVC and, in one case, showed the absence of the right superior vena cava. Electrocardiograms showed the field hockey player to have an ectopic atrial rhythm with left axis deviation of the frontal plane P-wave and the ice hockey player to have normal sinus rhythm. Symptom-limited treadmill testing revealed nothing abnormal, and after explaining the possible rhythm instability and the potential risk associated with cardiac surgery, the subjects were permitted full participation in competitive sports. Although information is scarce, available data on PLSVC suggest it is benign for competitive athletes. Nevertheless, complications arising from other cardiovascular anomalies, from potential cardiac rhythm disturbances, and from cardiac surgery necessitated by major injuries should be considered prior to participation in competitive sports.

A locus for female discrimination behavior causing sexual isolation in Drosophila.

The genetic basis of sexual isolation that contributes to speciation is one of the unsolved questions in evolutionary biology. Drosophila ananassae and Drosophila pallidosa are closely related, and postmating isolation has not developed between them. However, females of both species discriminate their mating partners, and this discrimination contributes to strong sexual isolation between them. By using surgical treatments, we demonstrate that male courtship songs play a dominant role in female mate discrimination. The absence of the song of D. pallidosa dramatically increased interspecies mating with D. ananassae females but reduced intraspecies mating with D. pallidosa females. Furthermore, genetic analysis and chromosomal introgression by repeated backcrosses to D. pallidosa males identified possible loci that control female discrimination in each species. These loci were mapped on distinct positions near the Delta locus on the middle of the left arm of the second chromosome. Because the mate discrimination we studied is well developed and is the only known mechanism that prevents gene flow between them, these loci may have played crucial roles in the evolution of reproductive isolation, and therefore, in the speciation process between these two species.

Genetic variation and correlations among responses to five insecticides within natural populations of Drosophila melanogaster (Diptera: Drosophilidae).

To investigate the genetic basis of cross-resistance to insecticides, natural populations of Drosophila melanogaster (Meigen) were first collected from four different locations in Japan. After 10-80 isofemale lines of each population had been established in a laboratory, the susceptibility of each line to each of the insecticides permethrin, malathion, fenitrothion, prothiophos, and DDT was examined. Broad ranges of continuous variation in susceptibility to all the chemicals were observed within each natural population as a whole. In addition, highly significant correlations among responses to organophosphates were observed. However, based on the coefficients of determination, about less than half of variation in responses to one insecticide could be explained by variation in responses to another insecticide, suggesting that not only a common resistance factor but also other factors could be involved in a natural population. Genetic analyses by using resistant and susceptible inbred lines from the same natural population demonstrated that resistance to organophosphates in some resistant lines could be due to a single or tightly linked factors, and that resistance in the other line may be due to more than one major factor. These observations could suggest that several resistance factors may be involved within each natural population, and that some of major factors could contribute to correlations among responses to organophosphates. These major factors could then contribute to the broad ranges of continuous variation observed at the level of the populations.

Mate choice in Drosophila melanogaster and D. sechellia: criteria and their variation depending on courtship song.

Courtship song is one of the most important male signals in Drosophila mating. A female D. melanogaster copulates more readily when given a conspecific type of courtship song. Female D. melanogaster accepted winged D. sechellia more than wingless ones in a no choice test. Copulation frequencies varied between strains and were significantly correlated with male mating propensity of D. sechellia. Females from three of five strains of D. sechellia accepted winged D. melanogaster less than wingless ones in no choice tests, suggesting that D. melanogaster songs reduce mating in D. sechellia females. Multiple choice tests showed that males prefer conspecifics. In female choice tests, D. melanogaster females copulated with winged heterospecific D. sechellia males more than with wingless conspecific D. melanogaster males in the confined condition, suggesting that song differences between D. melanogaster and D. sechellia affect D. melanogaster females less than the absence of courtship song. Copyright 2000 The Association for the Study of Animal Behaviour.

Physiological profile of middle-aged and older climbers who ascended Gasherbrum II, an 8035-m Himalayan peak.

BACKGROUND: The purpose of this study was to investigate the physiological characteristics of a group of middle-aged and older Japanese climbers who ascended Gasherbrum II, an 8035-m peak in the Karakoram Range of the Himalayas. METHODS: Body composition, cardiac structure, and respiratory gas exchange during exercise were estimated in eight climbers with differing levels of experience (seven men and one woman, aged 54 to 63 years) 6 months before their expedition. RESULTS: Using supplementary O2, the four experienced climbers ascended beyond Camp 4 (7400 m) without showing any health problems and were able to attempt the summit. In contrast, the others, who had minimal experience at extreme altitude, suffered from altitude sickness on the way to Camp 4. Body mass index values were relatively high, but their low percentage of body fat (14.9%-21.4%) was indicative of the climbers' substantial lean body weight. Cardiac structures were generally normal, although three experienced male climbers had borderline hypertension and eccentric hypertrophy of the left ventricle. Peak VO2 ranged from 30.9 to 45.6 ml/kg/min, and no significant relationship between fitness level and the success or failure of the ascent was evident. CONCLUSIONS: Even sexagenarians are capable of safely climbing 8000-m peaks with supplementary O2. An exceptionally high fitness level, as is seen in elite older athletes, does not appear to be required. What is essential, however, is moderate fitness, good health, and extensive experience.

Courtship song recognition in the Drosophila melanogaster complex: heterospecific songs make females receptive in D. melanogaster, but not in D. sechellia.

The courtship song emitted by male wing vibration has been regarded as one of the most important signals in sexual isolation in the species of the Drosophila melanogaster complex. Inter- and intraspecific crosses were observed using males whose wings were removed (mute) or females whose aristae were removed (deaf). Females of D. melanogaster, D. simulans, and D. mauritiana mated with heterospecific males in the song-present condition (cross between normal females and winged males) more often than in the no-song condition (cross between normal females and wingless males or between aristaless females and winged males) or they showed no preference between the two conditions. It is possible that in these females heterospecific courtship songs play a role as if they were conspecific. In contrast, the females of D. sechellia mated with D. melanogaster or D. simulans males in the no-song condition more often than in the song-present condition, suggesting that they reject males with heterospecific song. Female mate recognition depending on the courtship song in D. melanogaster, D. simulans, and D. mauritiana is considered to be relatively broader and that in D. sechellia narrower.

Seasonal fluctuation in susceptibility to insecticides within natural populations of Drosophila melanogaster: empirical observations of fitness costs of insecticide resistance.

To investigate genetic variation and seasonal fluctuation in susceptibility to insecticides, natural populations of Drosophila melanogaster were collected from Katsunuma in mid summer and late fall for two consecutive years. After isofemale lines of each population collected in each season had been established in a laboratory, the susceptibility of each line to five insecticides, including permethrin, malathion, prothiophos, fenitrothion, and DDT, was examined. Lines of each population exhibited the broad ranges of variation in susceptibility to all chemicals. Comparison between populations in different seasons indicated that genetic variation in susceptibility to organophosphates fluctuated in consistency with the population size, in which the susceptibility increased in fall. In addition, highly significant correlations were observed among responses to organophosphates, and the correlations also fluctuated with seasons. On the other hand, genetic variation in susceptibility to permethrin and DDT was less fluctuated. These results suggest that not only a common resistance factor for organophosphate resistance but also different resistance factor(s) for each insecticide could be involved within a natural population, and that the fluctuation observed in the susceptibility to organophosphates could be associated with fitness costs of organophosphate resistance factor(s).

Matrix metalloproteinase and tissue inhibitor of metalloproteinase in serum and lavage synovial fluid of patients with temporomandibular joint disorders.

We measured matrix metalloproteinases (MMPs) and tissue inhibitor of metalloproteinases (TIMP) in temporomandibular joint (TMJ) disorders. All patients were fully investigated, by visual analogue pain scores, plain radiographs and double-contrast arthrotomograms. The patients were grouped according to whether or not they were in pain. There were 35 patients with painful joints; 16 painless crepitating joints and 10 with chronic closed locked joints. A further group of 9 volunteers with no symptoms of TMJ abnormalities were used as controls. We found that synovial fluid concentration of MMP-3 was significantly increased (1117.2 (164.0) ng/ml) (P< 0.05) in the painful group compared with controls (436.2 (94.8) ng/ml) and with the two groups with painless TMJ (475.0 (113. 0) ng/ml/crepitation, and 516.0 (115.1) ng/ml/closed locked joints). MMP-1 and TIMP-1 were not recordable in most joints, and the serum concentrations of MMP-1, MMP-3, and TIMP-1 were similar to those in controls in all groups. There was no correlationship between MMP-3 concentration and joint morphology as shown by plain radiographs and double contrast arthrotomograms. These findings indicate that the synovia of painful joints are inflamed.

[Obesity, insulin resistance and the implication of thiazolidinediones].

The mechanism of insulin resistance in obesity is not fully understood. In muscle cells, the number of insulin receptor, the function of glucose transporter 4 and the activity of tyrosine kinase decrease. The rink of body fat accumulation and insulin resistance in muscle is thought through free fatty acid and tumor necrosis factor alpha secreted in adipose tissue. Thiazolidinediones (TZDs) are useful to reduce insulin resistance especially in obesity. TZDs seem to cause small weight gain, but to reduce visceral fat in 12-24 weeks. In longer period, it hasn't been studied very much. There are some unsolved problems. So now, targets of TZDs are obese diabetes failed in other medicines. When using TZDs, be cautious of excess eating and physical inactivity.

Dietary sodium, an independent determinant for urinary deoxypyridinoline in elderly women. A cross-sectional study on the effect of dietary factors on deoxypyridinoline excretion in 24-h urine specimens from 763 free-living healthy Japanese.

OBJECTIVE: To investigate the effect of sodium, protein and calcium in habitual diets on bone resorption. DESIGN: A cross-sectional study. SETTING: A community-based study. SUBJECTS: Healthy free-living male (n=342) and female (n=421) volunteers aged 20-79 y recruited for a health and nutrition examination survey conducted by a local government. METHODS: Bone resorption was assessed by the measurement of free deoxypyridinoline in 24 h urine. Dietary assessment was by one-day dietary record method. Sodium and urea in 24 h urine were also measured for assessment of sodium and protein intake. The relationships between deoxypyridinoline excretion and the dietary factors were examined using correlation and multiple regression statistics. RESULTS: In women aged 50-79 y, protein intake was positively associated with deoxypyridinoline excretion (P<0.05); and the urinary deoxypyridinoline/creatinine ratio was positively associated with both the urinary calcium/creatinine ratio (P<0.01) and sodium/creatinine ratio (P<0.05). In the multiple regression model, the association of the deoxypyridinoline/creatinine ratio and sodium/creatinine ratio was still significant (P<0.05) after adjustment for possible confounders, in this sex and age group. CONCLUSION: In elderly women, habitual excess sodium in diets may result in bone loss through accelerated bone resorption.

Effects of troglitazone on fat distribution in the treatment of male type 2 diabetes.

We investigated the efficacy of additional administration of 400 mg troglitazone (+T), which became available as a treatment for type 2 diabetes following the demonstration of its ability to reduce insulin resistance, in combination with diet (D + T) or sulfonylurea (S + T) therapy. Body fat area as determined by computed tomographic (CT) scanning at the umbilical level, as well as several clinical and biochemical parameters of glycemic control and lipid metabolism, were compared before and after 3 months of additional treatment with troglitazone. The body mass index (BMI) tended to increase in both groups (22.7 +/- 0.6 v 23.2 +/- 0.6 kg/m2 in D + T, nonsignificant [NS]; 22.2 +/- 0.5 v 22.3 +/- 0.5 kg/m2 in S + T, NS), while it tended to decrease in the control group (only diet therapy, 23.6 +/- 0.6 v 23.1 +/- 0.8 kg/m2, NS). Mean blood pressure ([BP] 96 +/- 3 v 89 +/- 4 mm Hg, P < .05) decreased significantly in the D + T group. Changes in the glycemic and lipid profile and leptin did not reach statistical significance. The D + T group showed a significant decline in immunoreactive insulin ([IRI] 12.4 +/- 1.2 v 8.0 +/- 1.0 microU/mL, P < .05), reflecting markedly reduced insulin resistance, as well as a significant increase in plasma insulin-like growth factor-1 ([IGF-1] 175.7 +/- 14.2 v 189.8 +/- 12.6 ng/mL, P < .05). A slight weight gain was associated with a tendency for subcutaneous fat to increase, while visceral fat decreased in both troglitazone-treated groups. The decrease in the visceral to subcutaneous fat ratio (V/S ratio) was statistically significant in the D + T group (1.09 +/- 0.11 v 0.94 +/- 0.09, P < .05), while the V/S ratio in the control group did not change. A notable finding of this study is the difference in the response to troglitazone between subcutaneous and visceral adipose tissue. It is suggested that troglitazone may exert beneficial effects by reducing visceral fat.

[Mutagenicity studies of magnesium sulfate--reverse mutation test with bacteria and chromosomal aberration test with mammalian cells in culture].

The mutagenicity potential of magnesium sulfate was re-assessed using the current procedure of the reverse mutation test with bacteria and chromosomal aberration test with mammalian cells (a Chinese hamster lung fibroblast cell line; CHL/IU) in culture. In the reverse mutation test with bacteria, Salmonella typhimurium TA100, TA98, TA1535 and TA1537 and Escherichia coli WP2 uvrA were use and the maximum dose level was set at 5000 micrograms/plate irrespective of the absence or presence of metabolic activation. Five dose levels (313-5000 micrograms/plate) were selected for all strains except for TA98 without metabolic activation and for TA1537 with metabolic activation, for which 6 dose levels (156-5000 micrograms/plate) were selected. Magnesium sulfate induced no increase in the number of colonies with reverse mutation in any of the strains irrespective of the absence of presence of metabolic activation in the dose-range-finding study or in the main study. In the chromosomal aberration test with mammalian cells, a Chinese hamster lung fibroblast cell line (CHL/IU) in culture was used and the maximum dose level was set at 5.0 mg/mL both in the direct and metabolic activation methods. Three dose levels (1.25-5.0 mg/mL) were selected. Magnesium sulfate induced no increase in the incidence of cells with chromosomal aberration or those with genome mutation (polyploidy) in any of the strains irrespective of the absence of presence of metabolic activation. Thus, it is concluded that magnesium sulfate does not have mutagenic potential under the presence experimental conditions.

Optical imaging of the spontaneous neuronal activities in the male rat major pelvic ganglion following denervation of the pelvic nerve.

Measurement of groups of neuronal activities following pelvic nerve transection to the major pelvic ganglion (MPG) of the rat was performed using voltage-sensitive dye (RH795) and an optical recording system. In control MPG, averaged neuron diameters were 32.0 +/- 0.6 x 22.6 +/- 0.4 microm. Application of KCl (10-50 mM) to the ganglia exhibited excitation which increased in a dose-dependent fashion. Fluctuating membrane potentials were not observed in control ganglion neurons. After the denervation of pelvic nerve chronically (2-6 weeks), the spontaneous neuronal activities were recorded in 91% of the experiments (n = 32). The activity was occurring somewhat periodically (2-15 s). Averaged neuron diameters were 41.3 +/- 1.3 x 24.7 +/- 0.9 microm in denervated MPG which is significantly larger than control. Since average neuron size increased 4 weeks after the denervation, the new excitatory activities could have influenced the change of the neuron size. The new activities might produce contraction of target organs in the pelvic viscera.

The loss of outer capsid protein P2 results in nontransmissibility by the insect vector of rice dwarf phytoreovirus.

A transmission-defective (TD) isolate of rice dwarf phytoreovirus lacked the ability to infect cells when derived from the virus-free insect vector Nephotettix cincticeps. Analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the purified virus showed that among six structural proteins, the P2 outer capsid protein (encoded by genome segment S2) was absent from the TD isolate, whereas all six proteins were present in the transmission-competent (TC) isolate. P2 was not detected on immunoblots of rice plants infected with the TD isolate. Genome segment S2 and its transcript were detected in both TD and TC isolates. Sequence analysis of the S2 segment of the TD isolate revealed the presence of a termination codon due to a point mutation in the open reading frame, which might explain the absence of P2 in the TD isolate. These results demonstrate that the P2 protein is one of the factors essential for infection by the virus of vector cells and, thus, influences transmissibility by vector insects.

Genetic analysis of Drosophila virilis sex pheromone: genetic mapping of the locus producing Z-(11)-pentacosene.

Z-(11)-pentacosene, Drosophila virilis sex pheromone, is predominant among the female cuticular hydrocarbons and can elicit male courtship behaviours. To evaluate the genetic basis of its production, interspecific crosses between D. novamexicana and genetically marked D. virilis were made and hydrocarbon profiles of their backcross progeny were analysed. The production of Z-(11)-pentacosene was autosomally controlled and was recessive. Of the six D. virilis chromosomes only the second and the third chromosomes showed significant contributions to sex pheromone production, and acted additively. Analysis of recombinant females indicated that the locus on the second chromosome mapped to the proximity of position 2-218.