Study on the effect of mouth-guards on muscle strength

最近スポーツ外傷の予防効果に加えて,マウスガードの筋力発揮増強効果について関心が高まってきている.本研究では市販マウスガード(FMG)とカスタムメイドのマウスガード(CMG)の2タイプのマウスガードを用いて,マウスガードが握力,背筋力,等速性膝関節伸展筋力,等速性膝関節屈曲筋力,最大ペダリングパワーに及ぼす効果について検討した.結果は次の通りである.1.FMG およびCMG のいずれのマウスガードにも握力,背筋力に対する筋力増強の効果はみられなかった.2.CMG には等速性膝関節伸展筋力に対して有意な増強効果が認められた.しかしFMG およびCMG のいずれのマウスガードにも等速性膝関節屈曲筋力に及ぼす効果は認められなかった.3.CMG には最大ペダリングパワーに対する有意な増強効果が認められたが,FMG には認められなかった.4.以上の結果から,CMG にはゆっくりした速度の等速性運動において筋力発揮に効果のあることが示唆された.As well as for their protective effect against sports injuries, interest is increasing in the value of mouth-guards for augmenting muscle strength. In this study the influence of two types of mouth-guards -commercial mouth-guards (FMG) and custom-made mouth-guards (CMG) - on grip power, back strength,peak torque in isokinetic knee extension, peak torque in isokinetic knee flexion and peak pedaling powerin rugby players are examined. The results are as follows. 1. No augmentation effect for grip power or back strength were noted in either of FMG and CMG. 2. A significant augmentation effect for peak torque in isokinetic knee extension was observed in CMG.However, neither FMG and CMG showed any affect on peak torque in isokinetic knee flexion. 3. A maximal pedaling power augmentation effect was noted in CMG but not in FMG.4. From the above-mentioned results, it was concluded that CMG had an augmentation effect on themuscle strength displayed in slow speed isokinetic exercises

Determinants of the daily rhythm of blood fluidity

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Production of Interleukin 2 in Human Peripheral Blood Lymphocytes: Optimal Condition for its Culture

For the assay of the production of Interleukin 2 (IL-2) in human peripheral blood lymphocytes (human PBL), a study was made on the optimal condition for its culture. 1) The optimal condition for the production of IL-2 was considered to be incubation time of 24 hr, number of PBL of 1 x 106 cells/ml, and phytohemagglutinin-M (PHA-M) concentration of 1 — 5% 2) By one way mixed lymphocyte reaction (one way MLR), IL-2 activity similar in level to that by PHA-M stimulation could also be obtained. It was maximal at the 4th day of culture. 3) By PHA-P (0.06%) stimulation, IL-2 could also be produced similar to that by PHAM stimulation but it decreased in the order of Con A, PWM and PPD and hardly any production of IL-2 could be observed by LPS

Interleukin-2 Production and Lymphocyte Proliferation in Aged and Young Humans

A study was made on the effect of aging on the production of Interleukin-2 (IL-2) and lymphocyte proliferation of human peripheral blood lymphocytes. 1) In comparison with young individuals, IL-2 production tended to decrease in aged individuals, while lymphocyte proliferation showed a significant decrease. 2) A significant correlation was observed between IL-2 production and lymphocyte proliferation in both the aged and young human populations. 3) IL-2 production showed a negative correlation with Leu-2a positive rate and a positive correlation with Leu-3a/Leu-2a ratio in aged individuals

Detection of Lymphocyte Subsets by Monoclonal Antibodies in Aged and Young Humans

With the use of Leu-series monoclonal antibodies, peripheral blood lymphocyte subsets in aged and young humans were determined. 1) In comparison with young individuals, Leu-1+ cells and Leu-2a+ cells were decreased, whereas Leu-7+ cells and Leu-3a/Leu-2a were increased in aged individuals. 2) No sex difference could be observed in lymphocyte subsets. 3) PHA response of lymphocytes showed a negative correlation with Leu-2a+ cells and a positive correlation with Leu-3a/Leu-2a in aged individuals

Immune Functions of Former Poison Gas Workers I. Mitogenic response of lymphocytes and serum factors

The relation of depressed immune function to carcinogenesis has been estimated in the living body. The authors have measured the immunological parameters in former poison gas workers, a group having a high risk of carcinogenesis, for comparison with age matched normal controls and the following results were obtained. 1) With regard to serum factors, no significant difference could be demonstrated between normal controls and poison gas workers in such immunoglobulins as IgG, IgA, and IgM, in acute phase reactants such as α1-AT, α1-AG, α2-HS and C3 and in such tumor markers as CEA, ferritin, and β2-microglobulin. Furthermore, no difference could be observed in the positive rate of immune complex and in complement activity. 2) No difference could be observed between the two groups with regard to tuberculin skin reaction and number of lymphocytes, but the longer the duration of work at the poison gas factory, the more significant was the increase in those who showed negative tuberculin skin reaction. 3) In comparison with normal controls, mitogenic response to PHA showed a significant decrease in poison gas workers, but no significant difference could be seen in mitogenic response to Con A and PPD and in mixed lymphocyte reaction. 4) No significant difference could be demonstrated between the two groups in the inhibitory effects of serum on mitogenic response to PHA and Con A and on mixed lymphocyte reaction

Vastus lateralis oxygenation during prolonged cycling in healthy males

This study examined the relationship between the acute cardiorespiratory and muscleoxygenation/blood volume changes during prolonged exercise. Eight healthy male volunteers (mean VO2max = 41.6 ± 2.4 ml/kg/min) performed 60 minutes submaximal cycling at 500f VO2max. Oxygen uptake (VO2) was measured by indirect spirometry, cardiac output (CO) was estimated via Portapres, and right vastus lateralis oxyhemoglobin/myoglobin (OxyHb/Mb), deoxyhemoglobin/myoglobin (DeoxyHb/Mb) and total hemoglobin/myoglobin (Total Hb/Mb) were recorded using near infrared spectroscopy. After 40 minutes of exercise, there was a significant increase in VO2 due to a significantly higher (a – v)O2diff. After 30 mins of exercise CO was unchanged, but there was a significant decrease in stroke volume and a proportionate increase in heart rate indicating the occurrence of cardiovascular drift. During the first few minutes of exercise, there was a decline in OxyHb/Mb and Total Hb/Mb while DeoxyHb/Mb remained unchanged. Thereafter OxyHb/Mb and Total Hb/Mb increased systematically until the termination of exercise while DeoxyHb/Mb declined. After 40 minutes of exercise, these changes were significantly different from the baselines values. There were no significant correlations between the changes in the NIRS variables and systemic VO2 or mixed (a – v)O2diff during exercise. These results suggest that factors other than localized changes in muscle oxygenation and blood volume account for the increased VO2 during prolonged submaximal exercise

加令によるヒトリンパ球の mitogen による lgG 産生の増強 : 特に T 細胞の効果について

When in vitro IgG production by mitogen-stimulated peripheral lymphocytes from healthy aged (70-93 year old) and young (20-29 year old) subjects was compared, it was found that the level of IgG production was elevated in the aged subjects. Co-culture studies were performed to determine whether the increase was clue to changes in T or non-T cells. IgG production was significantly higher when reference non-T cells from normal young adults were mixed with T cells from aged subjects than with T cells from young adults. In contrast, no significant difference in IgG production was observed when reference T cells from normal young adults were mixed with non-T cells from either young or aged subjects. The suppressor activity of Tγ cells and helper activity of non-Tγ T cells of young and aged subjects were then determined. The results revealed that the suppressor activity of Tγ cells of aged individuals was significantly lower than that of young adults, but the helper activity of non-Tγ T cells of young and aged subjects was comparable. These results indicate that the increase in production of IgG by the peripheral lymphocytes of aged individuals is due in part to changes in the T cells which are related to a decrease in suppressor activity of Tγ cells

Effects of exercise intensity on salivary level of secretory immunoglobulin A in patients with chronic obstructive pulmonary disease

外来通院中の慢性閉塞性肺疾患(COPD)患者5名を対象に, 運動負荷強度の違いが唾液中分泌型免疫グロブリンA(唾液中SIgA)に与える影響について検討した. 運動負荷は, 漸増シャトルウォーキングテスト(ISWT)を実施し, 最大歩行速度の40%および80%に相当する運動強度を算出し, 20分間のトレッドミル歩行をそれぞれ実施した(40% ISWT, 80% ISWT). 各運動負荷の実施前後に唾液採取を行い, 酵素標識免疫測定法を用いて, 唾液中SIgA濃度を測定し, 唾液中SIgA分泌速度を算出した. その結果, 40% ISWT後には5例中3例において唾液中SIgA分泌速度が低下し, 残りの2例において増加した. 一方, 80% ISWT後には5例中4例において唾液中SIgA分泌速度が低下し, 残りの1例において増加した. 健常者でも免疫機能が低下することが報告されている高強度の運動負荷に加え, COPD患者では低強度の運動負荷後でも免疫機能が低下する可能性が示唆された.The present study was designed to examine the effects of exercise intensity on local immunity of the upper respiratory tract. We measured salivary levels of secretory immunoglobulin A (SIgA) in five outpatients with chronic obstructive pulmonary disease (COPD). Maximum walking speed for each subject was determined by incremental shuttle walking test (ISWT). Exercise was 20 min walking on a treadmill at speeds of 40% or 80% of ISWT (40% or 80% ISWT). Saliva samples were collected before and after exercise. Salivary SIgA concentrations were measured by enzyme-linked immunosorbent assay and secretion rates (μg/min) were calculated by multiplying the salivary SIgA concentration by saliva flow rate (ml/min) for each subject. After 40% ISWT, the salivary SIgA secretion rate of three patients decreased but that of the other two increased. After 80% ISWT, the salivary SIgA secretion rate of four patients decreased while that of the remaining one increased. It was suggested that in addition to the decline in local immunity after high intensity exercise like that seen in a normal healthy subject, the local immunity of the upper respiratory tract for COPD patients deceased after even low intensity exercise