Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Masaru Ohtani is active.

Publication


Featured researches published by Masaru Ohtani.


Bioscience, Biotechnology, and Biochemistry | 2009

Effects of Oral Supplementation with Cystine and Theanine on the Immune Function of Athletes in Endurance Exercise: Randomized, Double-Blind, Placebo-Controlled Trial

Shigeki Murakami; Shigekazu Kurihara; Natsue Koikawa; Akira Nakamura; Kazuhiro Aoki; Hiroshi Yosigi; Keisuke Sawaki; Masaru Ohtani

Athletes become increasingly susceptible to infection with intense training that results in immune suppression. The immune state was investigated after administering cystine/theanine (CT), which has been reported to have an immune reinforcement effect, to athletes before training involving a prolonged period of intense exercise. Fifteen long-distance runners were each allocated to the CT or placebo group, and the test food was ingested for 10 d prior to the start of training. Clinical examinations were performed before and after the training. The results indicate a significant increase in the high-sensitivity C-reactive protein (hs-CRP) and neutrophil count in the blood, as well as a decreasing tendency for lymphocytes in the placebo group, but not the CT group. These observations suggest that the ingestion of CT contributed to suppressing the change in inflammatory response, prevented a decrease in the immune function, and prevented infection and reduced symptoms when infected associated with continuous intense exercise.


Journal of The International Society of Sports Nutrition | 2010

Suppression of exercise-induced neutrophilia and lymphopenia in athletes by cystine/theanine intake: a randomized, double-blind, placebo-controlled trial.

Shigeki Murakami; Shigekazu Kurihara; C Alan Titchenal; Masaru Ohtani

BackgroundIntense exercise induces increased blood neutrophil counts and decreased lymphocyte counts, and leads to inflammation and immunosuppression. It was previously reported that cystine and theanine (CT) supplementation by long-distance runners before a training camp suppressed the changes of these blood parameters observed in un-supplemented control subjects after the camp. The purpose of the present study was to determine the effects of CT supplementation on the inflammatory response and immune state before and after intense endurance exercise in long-distance runners at a training camp.MethodsSixteen long-distance runners were allocated to one of two groups given CT supplements (700 mg cystine + 280 mg theanine daily) or placebo (8 in each group) for 7 days prior to and during a 9-day training camp. Daily run training averaged 19.9 km/day prior to the camp and 28.6 km/day during the camp. On the initial and final days of the camp, blood samples were collected before and after 15 km morning interval running workouts (1000 m × 15 times) and analyzed for neutrophil and lymphocyte counts and myoglobin.ResultsThe relative change in exercise-induced blood neutrophil count (% of pre-exercise values) was significantly lower in the CT group than in the placebo group (163.3 ± 43.2% vs. 200.4 ± 19.6%, p = 0.044) on the initial day of camp, but not on the last day. The decline in lymphocyte count (% of pre-exercise values) was significantly less in the CT group than in the placebo group (60.2 ± 19.2% vs. 36.2 ± 12.0%, p = 0.010) on the initial day of camp, but not on the last day. In blood myoglobin, there was a trend toward lower % of pre-exercise values in the CT group (p < 0.09) on both measurement days.ConclusionCT supplementation significantly attenuated the increase in neutrophil count and the reduction in lymphocyte count induced by intense endurance exercise. These results suggest that CT supplementation may suppress the exercise-induced fluctuation of the blood immunocompetent cells and may help to reduce the alteration of the immune state.


Bioscience, Biotechnology, and Biochemistry | 2003

Effect of a selected amino acid mixture on the recovery from muscle fatigue during and after eccentric contraction exercise training.

Masaaki Sugita; Masaru Ohtani; Naokata Ishii; Kimiaki Maruyama; Kando Kobayashi

The effect of an amino acid mixture on the recovery from muscle fatigue after eccentric exercise (ECEX) training was examined in twenty-two male college students. The administration of 5.6 g of the amino acid mixture twice daily resulted faster recovery of muscle strength than that with a placebo. The oral administration of the amino acid mixture was proved to effective for muscle strength recovery after the eccentric exercise.


Bioscience, Biotechnology, and Biochemistry | 2001

Changes in Hematological Parameters of Athletes after Receiving Daily Dose of a Mixture of 12 Amino Acids for One Month during the Middle- and Long-distance Running Training

Masaru Ohtani; Kimiaki Maruyama; Shihoko Suzuki; Masaaki Sugita; Kando Kobayashi

Previous studies have shown that a mixture of amino acids, consisting of 9 essential amino acids and 3 non-essential amino acids was effective in facilitating muscle recovery from athletic activities. In this study, the objective was to determine whether this amino acid mixture improved the physical condition and associated blood parameters of athletes in training when administered for a prolonged period. Thirteen college middle- and long-distance runners were placed in a 6-month experiment and received the amino acid mixture at the dose of 2.2 g/day for one month, 4.4 g/day for one month, and 6.6 g/day for one month with washout periods between test periods. The physical condition was scored and blood samples were collected before and after each test period. When the subjects received 2.2 g of the amino acid mixture three times a day, the physical condition was significantly improved along with increases in red blood cell count, hemoglobin, hematocrit, serum albumin, and fasting glucose, and a decrease in creatine phophokinase (p<0.05), suggesting increased hematopoiesis and glycogenesis, and rapid alleviation of muscle inflammation by the amino acid mixture.


Journal of Strength and Conditioning Research | 2010

Cystine and Theanine Supplementation Restores High-Intensity Resistance Exercise-Induced Attenuation of Natural Killer Cell Activity in Well-Trained Men

Shigeo Kawada; Kando Kobayashi; Masaru Ohtani; Chiho Fukusaki

Kawada, S, Kobayashi, K, Ohtani, M, and Fukusaki, C. Cystine and theanine supplementation restores high-intensity resistance exercise-induced attenuation of natural killer cell activity in well-trained men. J Strength Cond Res 24(3): 846-851, 2010-We investigated the effects of supplementation with cystine, a dipeptide of cysteine, and theanine (CT), a precursor of glutamate, on immune variables during high-intensity resistance exercise. Cysteine and glutamate are involved in the formation of glutathione, which modulates the activity of natural killer (NK) cells. In this double-blinded clinical trial, 15 well-trained men (aged 22.8 ± 4.0 years) were divided into 2 groups: placebo (n = 7) and CT (n = 8). The placebo group was administered a powder containing cellulose (950 mg) and glutamate (30 mg), whereas the CT group was administered a powder containing cystine (700 mg) and theanine (280 mg), once daily for 2 weeks. The subjects trained according to their normal schedule (3 times per week) in the first week and trained at double the frequency (6 times per week) in the second week. Concentrations of immunoglobulin (Ig)M, interleukin (IL)-6, IL-8, and salivary IgA and the leukocyte count did not change significantly in either group. There was a significant decrease (p ≤ 0.05) in the NK cell activity (NKCA) in the placebo group after the second week compared with that in the CT group (placebo: 69.2 ± 16.1% vs. CT: 101.7 ± 38.7%). Phytohemagglutinin-induced lymphocyte blastoid transformation did not change significantly in either group. These results suggest that NKCA is not affected in a normal training schedule with or without CT supplementation. However, high-intensity and high-frequency resistance exercises cause attenuation of NKCA, which CT supplementation appears to restore. Therefore, in practical application, CT supplementation would be useful for athletes to restore the attenuation of NKCA during high-intensity and high-frequency training.


American Journal of Physiology-regulatory Integrative and Comparative Physiology | 2010

Increased oxygen tension attenuates acute ultraviolet-B-induced skin angiogenesis and wrinkle formation

Shigeo Kawada; Masaru Ohtani; Naokata Ishii

Acute ultraviolet (UV)-B irradiation causes skin wrinkle formation associated with hyperplasia of cutaneous blood vessels. This study reports that increased dermal oxygen tension attenuates acute UVB-induced angiogenesis and wrinkle formation. Twenty-four hairless mice (HOS:HR-1) were assigned to 3 groups: 1) control group, 2) UVB-irradiated (UVB) group, and 3) UVB-irradiated and hyperoxia-exposed (UVB+HO) group. The backs of the mice were exposed to UVB irradiation 3 times per week for a 5-wk period. To increase dermal oxygen tension, the mice were exposed to hyperoxia (90% oxygen) for 2 h immediately after each UVB irradiation. Hyperoxic exposure increased dermal oxygen tension by about 10 times compared with the control level. Degree of wrinkle formation and epidermal thickness increased significantly after a 5-wk UVB-irradiation period, whereas hyperoxic exposure attenuated these increases. Tissue adenosine triphosphate concentration and angiogenesis increased significantly only in the UVB group compared with the control group. Although the expression of hypoxia inducible factor-1alpha mRNA, a key molecule for angiogenesis, increased significantly in the UVB and UVB+HO groups compared with the control group, the protein level increased significantly only in the UVB group. The activity of matrix metalloproteinase-2 and -9, critical molecules for angiogenesis, did not increase in the UVB and UVB+HO groups compared with the control group. Active type 1 collagenase activity and soluble collagen content in all of the groups were roughly similar. These results suggest that increased dermal oxygen tension attenuates angiogenesis and wrinkle formation following acute UVB irradiation.


Journal of Strength and Conditioning Research | 2008

Effects of pre-exposure to hyperbaric hyperoxia on high-intensity exercise performance

Shigeo Kawada; Kohei Fukaya; Masaru Ohtani; Kando Kobayashi; Chiho Fukusaki

This study comprised 2 main experiments: one was to determine the oxidative DNA damage under hyperbaric hyperoxia (HBO), and the other was to evaluate the effects of pre-exposure to HBO on high-intensity exercise performance. Healthy subjects (n = 8) inspired 100% O2 in an experimental chamber at a pressure of 1.3 atmospheres absolute (ATA) for 50 minutes once per week for 2 weeks. Urinary 8-hydroxy-2′-deoxyguanosine (8-OHdG) was measured as a marker of DNA oxidative damage on day 0 and on days 1, 3, and 5 after each HBO exposure. To investigate the effects of pre-exposure to HBO on high-intensity exercise performance, subjects (n = 6) performed maximal isometric knee extensor exercise (30 repetitions × 2 sets) with and without HBO pre-exposure (100% O2 at 1.3 ATA for 50 minutes). Urinary 8-OHdG did not show any significant change after HBO exposure. Isometric knee extensor torque was significantly lower during the first half of the first set of exercises after HBO pre-exposure compared with the normobaric normoxia (NBO) trial. The decreased torque was associated with the lower integrated electromyography with respect to time. Changes in the degree of ischemia-reperfusion in the vastus lateralis muscle during exercise were larger in the HBO pre-exposure trial than in the NBO trial. Muscle fatigue index, serum lactate concentration, heart rate, and systolic blood pressure showed no differences between the 2 trials. These results indicated that HBO exposure was harmless to DNA, and HBO pre-exposure did not enhance high-intensity exercise performance. As a practical application, athletes who require maximal muscle strength should not inspire high-concentration of O2 just before their competitions because it might, as the case may be, impair their performance.


Journal of Clinical Biochemistry and Nutrition | 2012

Amino acid and vitamin supplementation improved health conditions in elderly participants.

Masaru Ohtani; Shigeo Kawada; Taizo Seki; Yasuyuki Okamoto

The purpose of this study was to investigate the effects of supplementation with amino acids and vitamins on health conditions in unhealthy older people. One bedridden inpatient group (n = 10; mean age, 79.8 ± 8.5 y) and one outpatient group (n = 9; mean age, 72.9 ± 12.2 y) participated in this study. A mixture supplementation with amino acids containing arginine (500 mg/day), glutamine (600 mg/day), and leucine (1200 mg/day), and 11 kinds of vitamins was daily administrated for 8 weeks. In both groups, general blood biomarkers such as white blood cell count, natural killer cell activity, and C-reactive protein levels were measured. All measurements were taken before (baseline), at 4 weeks (mid-point), and after each trial (post-point). At mid-point, natural killer cell activity in the outpatient group increased significantly compared to baseline. At post-point, natural killer cell activity in the outpatient and inpatient groups increased significantly compared to baseline. The other blood biomarkers did not show any significant change throughout the trial. This pilot study suggested that a mixture of arginine, glutamine, leucine, and vitamins is useful to support innate immunity in unhealthy older people, even if their diseases, symptoms, and prescribed medicines are different.


Acta Physiologica Hungarica | 2013

Resistance exercise combined with essential amino acid supplementation improved walking ability in elderly people.

Shigeo Kawada; Yasuyuki Okamoto; K. Ogasahara; S. Yanagisawa; Masaru Ohtani; Kando Kobayashi

We investigated the effects of resistance exercise combined with essential amino acid supplementation on psoas major muscle (PMM) hypertrophy and walking ability in elderly individuals. Twenty-nine healthy elderly individuals were assigned to 3 groups: (1) E (exercise), (2) A3 (exercise combined with 3.0 g of essential amino acid supplementation), and (3) A6 (exercise combined with 6.0 g of essential amino acid supplementation). To evaluate walking ability, the participants underwent the following 3 types of tests: the (1) 10-meter walk (10-W), (2) 10-meter walk involving crossing of obstacles (10-W + O), and (3) 6-minute walk (6M-W) tests. The 6-month training program resulted in significant PMM hypertrophy in all groups independent of amino acid supplementation. The extent of hypertrophy in the participants who took amino acids was dose-dependent, although the differences were not significant. Groups A3 and A6 demonstrated improvements in the 10-W and 10-W + O tests, whereas no improvement was observed in group E, regardless of PMM hypertrophy. Furthermore, group A6 showed an improvement in the 6M-W test. These results suggest that our training program causes PMM hypertrophy, whereas the training program combined with essential amino acid supplementation improves walking ability.


Medicine and Science in Sports and Exercise | 2001

AMINO ACID SUPPLEMENTATION AFFECTS HEMATOLOGICAL AND BIOCHEMICAL PARAMETERS IN ELITE RUGBY PLAYERS

Masaru Ohtani; Kimiaki Maruyama; C A. Titchenal; Kando Kobayashi

Individual amino acid supplementation affects various types of athletic performance. However, little information on combinations of amino acids is currently available. This study evaluated an amino acid mixture containing L-leucine, L-isoleucine, L-valine, L-arginine, and L-glutamine to 3.6 g of total amino acids per dose. Twenty-three rugby players were given 3.6 g, twice, daily of the amino acid mixture for 90 days (June-August 1994) and blood samples were collected for analyses in September 1993, March 1994, September 1994, and September 1995. After 90 days of supplementation, almost all of the athletes reported improvement in vigor and earlier recovery from fatigue. Significant increases (P<0.05) were observed in hemoglobin, RBC count, hematocrit, and serum iron by amino acid supplementation. Significant increases (P<0.05) were also noted in total cholesterol and low-density lipoprotein along with decreased (P<0.05) alkaline phosphatase. All values reverted to original levels when measured after one year of continued training without supplementation.

Collaboration


Dive into the Masaru Ohtani's collaboration.

Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Researchain Logo
Decentralizing Knowledge