Characteristics of lower limb muscle activity during upper limb elevation in badminton players.

[Purpose] To clarify the characteristics of postural control in badminton players by examining their lower-limb muscle activity during upper-limb elevation. [Subjects and Methods] Fourteen badminton players and 14 non-players were studied. The subjects were instructed to perform an upper-limb elevation task in order to measure the activities of the biceps femoris and biceps brachii. [Results] When elevating the dominant hand, the mean biceps femoris integrated electromyogram showed markedly higher values in the player group, for the contralateral compared with the ipsilateral leg. Similarly, when elevating the dominant hand, the difference in the maximum integrated electromyogram response time between the ipsilateral and contralateral legs was significantly smaller in the players compared with non-players. [Conclusion] It may be possible to reduce the time needed to elevate the dominant hand by shifting lower-limb activity from the ipsilateral to the contralateral leg more quickly, while increasing the rate of rise in contralateral leg muscle activity.

Differences between the Sexes in the Relationship between Chronic Pain, Fatigue, and QuickDASH among Community-Dwelling Elderly People in Japan.

Chronic pain and fatigue have negative effects on the health, ADL, work, and hobbies of the elderly. As the proportion of people 65 years of age and older in the population increases, chronic pain and disability research regarding this group is receiving more consideration. However, little empirical evidence of the association between chronic pain, fatigue, and physical disability between the sexes is available. This study investigated the association between chronic pain, fatigue, and instrumental activities of daily living among community-dwelling elderly people by sex in Japan. Concerning the presence of chronic pain, 61% of males and 78% of females reported chronic pain, indicating that many elderly people living in the community suffer from chronic pain and fatigue on a daily basis. The number of sites of chronic pain was higher in females than in males (p = 0.016), with more chronic pain in the knees (p < 0.001) and upper arms (p = 0.014). Regarding chronic pain, males showed a higher correlation with QuickDASH-DS (rs = 0.433, p = 0.017) and QuickDASH-SM (rs = 0.643, p = 0.018) than females. Furthermore, fatigue also showed a higher correlation with QuickDASH-W (rs = 0.531, p = 0.003) in males than in females. These results indicate that the association between chronic pain, fatigue, and QuickDASH differed between the sexes among community-dwelling elderly people in Japan. A better understanding of the risk factors for elderly chronic pain and fatigue among sexes will facilitate the development of elderly healthcare welfare and policies.

High-throughput solid-phase extraction of metal ions using an iminodiacetate chelating porous disk prepared by graft polymerization.

A chelating porous sheet for use in solid-phase extraction was prepared by radiation-induced graft polymerization and subsequent chemical modifications. An epoxy-group-containing vinyl monomer was graft-polymerized onto a porous sheet made of polyethylene. The produced epoxy group of the graft chain was converted into an iminodiacetate group. The chelating porous sheet with a density of the iminodiacetate group of 2.1 mol/kg was cut into disks 13 mm in diameter to fit an empty cylindrical cartridge with a capacity of 6 mL. Breakthrough curves using the chelating-porous-disk-packed cartridge overlapped irrespective of the flow rate of the solution ranging up to 1500 mL/h because of negligible diffusional mass-transfer resistance of the copper ions to the iminodiacetate group of the graft chain.

Sweet taste threshold for sucrose inversely correlates with depression symptoms in female college students in the luteal phase.

Influences of depression symptoms on the sweet taste threshold were investigated in healthy college students (30 males and 40 females). Depression symptoms were scored by SDS (Self-Rating Depression Scale), and anxiety levels by STAI (State- and Trait-Anxiety Inventory). Recognition thresholds for sucrose were determined. In female students, the menstrual phase on the day of the experiment was self-reported. Depression symptoms, anxiety levels, and the recognition threshold for sucrose were not different among the 3 groups, i.e. males, females in the follicular phase, and females in the luteal phase. Depression symptoms were positively correlated with state and trait anxiety in all groups. The sweet taste threshold was inversely correlated with depression symptoms (r=-0.472, p=0.031) and trait anxiety (r=-0.506, p=0.019) in females in the luteal phase. In males as well as females in the follicular phase, however, no correlation between sweet taste threshold and depression was found. The results show that the recognition threshold for sucrose reduces with increased depression in females with a higher anxiety trait, but only in the luteal phase. It is hypothesized that brain regions, which spatially overlap and are responsible for both aversive emotions and gustatory processing, are susceptible to periodic changes in gonadal hormones due to the menstrual cycle.

The effect of anxiety on postural control in humans depends on visual information processing.

To examine the possibility that anxiety affects the control of postural balance, state anxiety, and body sway during orthostatic standing were measured twice in college students with an interval of 1 month. Correlations between the changes in state anxiety and the parameters of body sway were examined by Pearson's correlation analysis. The changes in the enveloped area of body sway and in the maximum length of the antero-posterior body sway showed a positive correlation with the changes in state anxiety (r = 0.543 and 0.659, respectively). The data showed that an increase in anxiety caused instability in the control of postural balance. These correlations were abolished when the eyes were closed. In conclusion, anxiety affects the processing of visual input and influences the net performance of postural control.

Effects of lumbar skin warming on gastric motility and blood pressure in humans.

We examined the possibility that lumbar skin warming can increase gastrointestinal motility by investigating the electrogastrogram (EGG), blood pressure, and heart rate with psychometric ratings in healthy humans. Scores of mood state profiles showed that lumbar skin warming (42 degrees C, 20 min) decreased tension-anxiety, depression, anger-hostility, fatigue, and confusion of the participants. A multiple bandpass filter analysis of EGGs showed that a postural transition from orthostatic to supine for measurement caused an increase in dominant frequency of 25-29% towards the frequencies of the normal interdigestive migrating motor complex (IMC). The spectral power of the IMC band, 2.55-3.05 cycles/min, was increased by 20 min-warming, reflecting the increase in gastric contractility. No increase in the spectral power was observed in the time-matched control group without skin warming. Therefore, an increase in contractility is a characteristic of lumbar skin warming. The systolic blood pressure increased by 15% during warm stimulation. Interbeat intervals were not influenced by warm stimulation. An analysis of interbeat intervals by a fast Fourier transform method showed that the cardiac sympathetic and parasympathetic nerves did not play a major role in raising the blood pressure. Vasoconstriction of the mesenteric artery was therefore considered to cause a blood pressure increase during warming. It is hypothesized that vasoconstriction of the visceral arteries by lumbar skin warming increases the blood pressure and gastrointestinal contractility.

The size of motoneurons of the gastrocnemius muscle in rats with diabetes.

Alterations in the number and size of motoneurons were studied in the medial gastrocnemius (MG) motor nucleus of diabetic rats (12 or 22 weeks after injection of storeptozotocin) and age-matched controls. Each group contained 6 animals. MG motoneurons were retrogradely labeled by dextran-fluorescein and the number and size of cell bodies were examined. Significantly fewer labeled MG motoneurons were found in the 22-week diabetic rats as compared with age-matched control animals. The mean soma diameter of MG motoneurons was significantly smaller in the 12- and 22-week diabetic animals. Furthermore the soma size for 22-week diabetic animals was smaller than for 12-week diabetic animals. The distribution of average soma diameters in the MG nucleus of control animals was bimodal; cells with larger average diameter were presumed to be alpha-motoneurons and those with smaller diameters were presumed to be gamma. Compared to control animals, the number of smaller MG motoneurons was reduced in 12 week diabetic animals. By 22 weeks, diabetic animals had no small MG motoneurons and the size distribution became unimodal. We conclude that there is a significant decrease in the absolute number and size of MG motoneurons in diabetic rats, with the possibility that the decrease occurred predominantly among the smaller gamma-motoneurons.

Effects of anticipatory anxiety and visual input on postural sway in an aversive situation.

We have previously reported that state anxiety scores were positively correlated with postural sway while standing upright and gazing at a visual target (Ohno et al., 2004 [16]). The present study examines the effect of anticipatory anxiety and visual input on postural control in healthy individuals. An unpredictable aversive sound (100dB SPL) was delivered in order to induce anticipatory anxiety. Participants were asked to stand upright on a force plate with their eyes open and closed, and their center of pressure (COP) was measured. Analysis of the postural parameters revealed that the path lengths of the COP and the enveloped areas were greater in the anticipatory situation with the aversive sound than in the silent situation. Fast Fourier transform analysis showed that the frequency component related to vestibular inputs (0.1-1.0Hz) was increased during the anticipatory situation. The lower frequency (<0.1Hz) component was decreased in the medio-lateral axis during anticipation with the eyes closed due to shifting mean power frequencies to high frequency. The results suggest that anticipatory anxiety in healthy participants amplified the sway regardless of whether the eyes were open or closed, and that the vestibular inputs greatly influenced the amplification of postural sway.

Characteristics of the control of standing posture during pregnancy.

During pregnancy, the physical and mental states greatly change. We investigated the influences of pregnancy and anxiety on postural control in pregnant women (P) standing upright in the late trimester. An analysis of posturograms revealed that the area of body sway and length of antero-posterior body sway were greater in P than those in non-pregnant controls (NP). No difference was found in the medio-lateral body sway between P and NP. Fast Fourier transform analysis of body sway showed that the percentile power of the 1.0-10.0Hz band in the medio-lateral axis was smaller in P than in NP irrespective of whether the eyes were open or closed. P were divided into a high (HA) and low (LA) anxiety group on the basis of state anxiety scored by Spielberger's State- and Trait-Anxiety Inventory. A positive correlation was identified between state anxiety and the area of body sway in HA standing with eyes open. This correlation was diminished when the eyes were closed. Body sway of over 1Hz is generally stabilized by somatosensory input, therefore, the results show that body sway in the medio-lateral axis is stabilized in P by increasing the sensitivity to somatosensory cues. High anxiety during pregnancy destabilizes the standing posture when the eyes are open. The correlation between anxiety and body sway revealed by our previous studies in college students was also confirmed in P, suggesting that humans with high anxiety abstract visual cues differently from those with low anxiety.

Pentavalent vanadium at concentration of the underground water level enhances the sweet taste sense to glucose in college students.

Underground water in volcanic areas contains vanadium when the basalt layer exists among igneous rocks. The concentration of vanadium in drinking water sometimes exceeds 0.8 microM in these areas, however, the physiological effects of vanadium, especially non-toxic effects, at concentrations lower than 1 microM are unknown. In the present experiments, we examined the effect of pentavalent vanadium and tetravalent vanadium at 0.8 and 8.0 microM concentrations on the recognition threshold to taste substances in healthy college students. Pentavalent vanadium, ammonium vanadate, lowered the sweet taste threshold to glucose at 0.8 and 8.0 microM as well. Tetravalent vanadium, vanadium sulfate, did not alter the threshold to glucose either at 8.0 microM or at 0.8 microM. Ammonium vanadate also decreased the sweet taste threshold to L-proline at 8.0 microM. Ammonium vanadate did not influence the sour taste threshold to hydrogen chloride. Neither ammonium sulfate nor ammonium bicarbonate altered the sweet taste threshold to glucose. Therefore, the effect of ammonium vanadate on the sweet taste threshold is attained by vanadium but not by ammonium. It was concluded that pentavalent vanadium at 0.8 microM intensifies the sweet taste sense to glucose rather specifically. We have first shown the physiological effect of vanadium at the concentration of the underground water level.

Occult fractures of articular eminence and glenoid fossa presenting as temporomandibular disorder: a case report.

We report an unusual case of occult fractures of the articular eminence and glenoid fossa due to a previous traffic accident presenting as a temporomandibular disorder. A 24-year-old Japanese man was referred for trismus and pain in the right temporomandibular joint, and was suspected of having temporomandibular disorder. Although the magnetic resonance image did not show displacement of the articular disk, T2-weighted images revealed disruption of the cortical low-intensity line of the right articular eminence. On a computerized tomography (CT) scan, an isolated bone fragment of the right articular eminence was clearly seen, and fractures of the right glenoid fossa and articular eminence were noted. The patient was treated by instructing him not to open his mouth widely and to remain on a soft diet for 4 weeks. A CT examination performed 1 year after the treatment showed complete healing of the fracture in the right articular eminence and glenoid fossa.