Search PubMed⌕ Search

Biomedical subjects

T Katsumura

Publications and source records attributed to T Katsumura.

At least 19 recordsLinked to original sources
PubMed2002

Quantitative effects of respiration on venous return during single knee extension-flexion.

Respiration and the muscle pump play major roles in increasing venous return. However, the relative contribution of each of these factors remains unclear. The present study investigates the quantitative effects of interaction between respiration and the muscle pump on femoral venous blood flow (FVBF) during a single voluntary knee extension-flexion (KEF) using duplex-Doppler ultrasound. During various respiration modes, which consisted of arrested respiration, normal respiration and deep respiration (inspiration or expiration), eight subjects performed a supine one-legged voluntary KEF. FVBF was measured during respiration only (Protocol A) and during KEF synchronized with respiration (Protocol B). The difference between FVBF values obtained in Protocol B and Protocol A was defined as DeltaFVBF. When KEF was synchronized with normal or deep respiration, FVBF with inspiration was significantly lower than that with expiration. However, DeltaFVBF was significantly higher with inspiration than with expiration during deep respiration but was not significant during normal respiration. Furthermore, DeltaFVBF was significantly higher at both normal and deep respiration than at arrested respiration. The effects upon the venous return during KEF differed between inspiration and expiration. The present findings indicate that during a single supine KEF, respiration might promote venous return to a range of 1.5- to 2.3-fold DeltaFVBF during arrested respiration.

Adult↗
PubMed2001

Validity of NIR spectroscopy for quantitatively measuring muscle oxidative metabolic rate in exercise.

The purpose of this study was to examine the validity of the quantitative measurement of muscle oxidative metabolism in exercise by near-infrared continuous-wave spectroscopy (NIRcws). Twelve male subjects performed two bouts of dynamic handgrip exercise, once for the NIRcws measurement and once for the (31)P-magnetic resonance spectroscopy (MRS) measurement as a standard measure. The resting muscle metabolic rate (RMRmus) was independently measured by (31)P-MRS during 15 min of arterial occlusion at rest. During the first exercise bout, the quantitative value of muscle oxidative metabolic rate at 30 s postexercise was evaluated from the ratio of the rate of oxyhemoglobin/myoglobin decline measured by NIRcws during arterial occlusion 30 s after exercise and the rate at rest. Therefore, the absolute values of muscle oxidative metabolic rate at 30 s after exercise [VO(2NIR(30))] was calculated from this ratio multiplied by RMRmus. During the second exercise bout, creatine phosphate (PCr) resynthesis rate was measured by (31)P-MRS at 30 s postexercise [Q((30))] under the same conditions but without arterial occlusion postexercise. To determine the validity of NIRcws, VO(2NIR(30)) was compared with Q((30)). There was a significant correlation between VO(2NIR(30)), which ranged between 0.018 and 0. 187 mM ATP/s, and Q((30)), which ranged between 0.041 and 0.209 mM ATP/s (r = 0.965, P < 0.001). This result supports the application of NIRcws to quantitatively evaluate muscle oxidative metabolic rate in exercise.

Adenosine Triphosphate↗
PubMed2000

Comparison of muscle oxygen consumption measured by near infrared continuous wave spectroscopy during supramaximal and intermittent pedalling exercise.

The two purposes of the present study were 1) to determine the oxygen consumption in working skeletal muscle from the oxygenation measured by near-infrared continuous-wave spectroscopy (NIRcws) with the arterial occlusion method during the resting condition, INT(VT), and INT(MAX) and 2) to examine whether the decline rate of oxygenation is related to maximal oxygen uptake. Eight healthy males (aged 19.8 +/- 0.4 yr, height 166.9 +/- 17.4 cm, weight 62.1 +/- 2.5 kg, and maximal oxygen uptake [VO2max] 55.9 +/- 1.9 ml/kg x min(-1)) took part in this study. The oxygenation was measured by NIRcws during the Wingate anaerobic test (WAnT) and two intermittent pedalling exercises of VT (INT(VT)) and maximal (INT(MAX)) work intensity. The decline rates of oxygenation obtained during the resting condition, INT(VT), and INT(MAX) with arterial occlusion were 0.43 +/- 0.05%/sec, 4.94 +/- 0.31%/sec, and 8.16 +/- 0.38%/sec, respectively, and that during the WAnT without arterial occlusion was 8.73 +/- 0.49%/sec. The decline rate of oxygenation during the WAnTwas significantly (p < 0.0001) related to maximal oxygen uptake (VO2max). These findings indicate that O2 is utilized from the early phase, even during a supramaximal pedalling exercise, and that the oxidative metabolic capacity may be a factor contributing to supramaximal exercises. Therefore the arterial occlusion method with NIRcws is suitable for the evaluation of the muscle O2 consumption during exercise noninvasively.

Adult↗
PubMed2000

Effects of epinephrine and lactate on the increase in oxygen consumption of nonexercising skeletal muscle after aerobic exercise.

The purpose of this study was to measure O2 consumption of nonexercising skeletal muscles (VO2nonex) at rest and after aerobic exercise and to investigate the stimulant factors of O2 consumption. In experiment 1, we measured the resting metabolic rate of the finger flexor muscles in seven healthy males by 31P-magnetic resonance spectroscopy during a 15 min arterial occlusion. In experiment 2, the VO2nonex of the finger flexor muscles was measured using near infrared continuous wave spectroscopy at rest, immediate postexercise, and 3, 5, 10, 15, and 20 min following a cycling exercise at a workload corresponding to 50% of peak pulmonary O2 uptake for 20 min. We also monitored deep tissue temperature in the VO2nonex measurement area and determined catecholamines and lactate concentrations in the blood at rest and immediate postexercise. VO2nonex at rest was 1.1 +/- 0.1 microM O2/S (mean +/- standard error) and VO2nonex after exercise increased 59.6 +/- 7.2% (p < 0.001) from the resting values. There were significant correlations between the increase in VO2nonex and the increase in epinephrine concentration (p < 0.01), and between the increase in VO2nonex and the increase in lactate concentration (p < 0.05). These results suggest that epinephrine and lactate concentrations are important VO2nonex stimulant factors.

Adult↗
PubMed2000

Quantification of ischemic muscle deoxygenation by near infrared time-resolved spectroscopy.

The purpose of this study was to quantify muscle deoxygenation in human skeletal muscles using near infrared time-resolved spectroscopy (NIRTRS) and compare NIRTRS indicators and blood saturation. The forearm muscles of five healthy males (aged 27-32 yrs.) were monitored for changes in hemoglobin saturation (SO2) during 12 min of arterial occlusion and recovery. SO2 was determined by measuring the temporal profile of photon diffusion at 780 and 830 nm using NIRTRS, and was defined as SO2-TRS. Venous blood samples were also obtained for measurements of SvO2, and PvO2. Interstitial PO2(PintO2) was monitored by placing an O2 electrode directly into the muscle tissue. Upon the initiation of occlusion, all parameters fell progressively until reaching a plateau in the latter half of occlusion. It was observed at the end of occlusion that SO2-TRS (24.1 +/- 5.6%) agreed with SvO2 (26.2 +/- 6.4) and that PintO2 (14.7 +/- 1.0 Torr) agreed with PvO2 (17.3 +/- 2.2 Torr). The resting O2 store (oxygenated hemoglobin) and O2 consumption rate were 290 microM and 0.82 microM s-1, respectively, values which reasonably agree with the reported results. These results indicate that there was no O2 gradient between vessels and interstisium at the end of occlusion.

Adult↗
PubMed2000

Vitamin E level changes in serum and red blood cells due to acute exhaustive exercise in collegiate women.

The purpose of this study was to investigate the change in vitamin E level in both serum and red blood cells (RBC) during exercise and to clarify the effect of vitamin E supplementation. Ten young sedentary female subjects received 200 mg D-alpha-tocopherol acetate daily for 1 wk after the initial exercise bout. After 1 wk of vitamin E supplementation, the same subjects repeated the same exercise. Before vitamin E supplementation, the alpha-tocopherol level in the serum (serum-alpha-tocopherol) did not change after exercise, but a significant decrease in the alpha-tocopherol level in RBC (RBC-alpha-tocopherol) was observed after exercise (p < 0.05). On the other hand, after vitamin E supplementation, the serum-alpha-tocopherol level decreased significantly after exercise (p < 0.05), while the RBC-alpha-tocopherol level was maintained after exercise. Furthermore, a negative correlation between the changes in serum- and RBC-alpha-tocopherol levels was observed only after vitamin E supplementation (r = 0.667, p < 0.05). The present results suggest that as RBC suffers oxidative stress, vitamin E in RBC is consumed to protect RBC from oxidative damage during exercise. These results also suggest that when there is a sufficient amount of vitamin E in the serum, vitamin E is shifted from the serum to RBC, resulting in a steady RBC-alpha-tocopherol level and a decrease in the serum-alpha-tocopherol level under oxidative stress such as exercise.

Adult↗
PubMed1999

Reduced blood flow in abdominal viscera measured by Doppler ultrasound during one-legged knee extension.

The redistribution of blood flow (BF) in the abdominal viscera during right-legged knee extension-flexion exercise at very low intensity [peak heart rate (HR), 76 beats/min] was examined by using Doppler ultrasound. While sitting, subjects performed a right-legged knee extension-flexion exercise every 6 s for 20 min. BF was measured in the upper abdominal aorta (Ao), right common femoral artery (RCFA), and left common femoral artery (LCFA). Visceral BF (BFVis) was determined by the equation [BFAo - (BFRCFA + BFLCFA)]. A comparison with the change in BF (DeltaBF) preexercise showed a greater increase in DeltaBFRCFA than in DeltaBFAo during exercise. This resulted in a reduction of BFVis to 56% of its preexercise value or a decrease in flow by 1,147 +/- 293 (+/-SE) ml/min at the peak workload. Oxygen consumption correlated positively with DeltaBFAo, DeltaBFRCFA, and DeltaBFLCFA but inversely with DeltaBFVis during exercise and recovery. Furthermore, BFVis (% of preexercise value) correlated inversely with both an increase in HR (r = -0.89), and percent peak oxygen consumption (r = -0.99). This study demonstrated that, even during very-low-intensity exercise (HR <90 beats/min), there was a significant shift in BF from the viscera to the exercising muscles.

Adult↗
PubMed1998

Viscous property and osteogenesis induction of hydroxyapatite thermal decomposition product mixed with gelatin implanted into rabbit femurs.

The viscosity of hydroxyapatite thermal decomposition product mixed with gelatin (HATDP-G) and the osteogenesis induced by this mixture were investigated. To determine the viscosity of HATDP-G, we measured the average diameter of a slumped mass of HATDP-G (0.5 ml) according to the American Dental Association Specification No. 8, with some modifications, and compared it with that of an equal mass of HATDP and of polymethylmethacrylate (PMMA) bone cement. The mean diameter of 10 samples each of HATDP-G, HATDP, and PMMA bone cement was 26.8+/-0.9 mm, 19.6+/-0.2 mm and 29.2+/-0.3 mm, respectively, 2 min after the mixing procedure. HATDP-G was injected into the bone marrow of the right femurs of 25 rabbits. As the control, gelatin with saline solution was injected into the left femurs. New bone formation was observed in all 20 femurs from three weeks after injection. No new bone formation was observed in the control femurs. The affinity index, a parameter of osteogenesis, was 19.8+/-6.1%, 27.5+/-2.6%, 52.9+/-9.5%, and 76.3+/-1.9% at 3, 6, 12 and 24 weeks after the injection, respectively. Significant increases in the affinity index were found between weeks 6 and 12, and weeks 12 and 24 (p < 0.05). Our findings indicated that HATDP-G might be successfully used as a bioactive bone cement.

Animals↗
PubMed1996

Non-penetrating traumatic tricuspid regurgitation after mitral valve replacement.

A case of traumatic rupture of the tricuspid chordae tendineae with severe regurgitation in a patient who previously had mitral valve replacement is presented. In this case, it is strongly suggested that a firm pericardial adhesion of the anterior right ventricular wall became a factor of the disruption of the tricuspid valve under a slight precordial blow.

Adult↗
PubMed1996

Relationships between exhaustive mood state and changes in stress hormones following an ultraendurance race.

To investigate how the pituitary-adrenal and sympathetic nervous hormones change in psychologically exhaustive states following an ultraendurance race, the Profile of Mood States (POMS), plasma ACTH, beta-endorphin, adrenaline, noradrenaline, and serum cortisol were measured in 29 male athletes two days before, immediately after, and one day after a triathlon. Psychological exhaustion was defined as possessing low POMS vigour and high fatigue immediately post-race. Eleven subjects met the criteria for the exhaustive group, and another ten were placed in the vigour group, which possessed high vigour regardless of fatigue score and the remaining eight subjects were excluded from analysis because they did not satisfy experimental protocol. Student's t-tests revealed no significant group differences in age, race time, pre-race POMS and hormone values. Immediately post-race, serum cortisol and plasma adrenaline did not differ between groups. However, significantly lower levels of plasma beta-endorphin (p = 0.03) and noradrenaline (p = 0.05), and relatively lower levels of plasma ACTH (P = 0.08) immediately post-race were observed in the exhaustive group when compared with the vigour group. We conclude that pituitary and sympathetic nervous hormone reactivity is attenuated following ultraendurance race in athletes showing psychological exhaustion and this is independent of race performance.

Adrenocorticotropic Hormone↗
PubMed1996

In vitro and in vivo testing of an implantable motor-driven left ventricular assist device.

A totally implantable motor-driven left ventricular assist device (LVAD) has been developed and tested. The performance of this LVAD was tested in a mock circulatory system. This pump provided 8 L/min of output against a mean afterload of 120 mm Hg with a filling pressure of 20 mm Hg when the pump was operated in the fill/empty mode. The right and left pumps were tested in a mock loop. The right pump afterload was kept in the range from 23-32 mm Hg. With increase in the left pump afterload, the pump power output varied from 1.64 to 2.37 W. The instantaneous motor power input varied from 22.6 to 30.6 W with the total system efficiency ranging from 6.7 to 9.4%. To date, 4 in vivo studies have been conducted for up to 12 h. Two animals survived 12 and 10 h, respectively. Termination was due to bleeding in 1 animal, vent tube obstruction in 1, and respiratory failure in 2. All animals died of technical failure. Another experiment is to be undertaken, and a newly designed cannula is now being manufactured.

Abdominal Muscles↗
PubMed1996

Noninvasive measures of oxidative metabolism on working human muscles by near-infrared spectroscopy.

The purpose of this study was to determine whether the initial rate of hemoglobin and myoglobin deoxygenation during immediate postexercise ischemia, a reflection of muscle O2 consumption (VO2mus), can be a quantitative measure of muscle oxidative metabolism. The finger flexor muscles of five healthy men (aged 25-31 yr) were monitored by 31P-magnetic resonance spectroscopy for changes in phosphocreatine (PCr), Pi, and pH. Tests were conducted during 15 min of cuff ischemia and during 5 min of submaximal isotonic grip exercise at 10, 20, 30, and 40% of maximal voluntary contraction, one contraction every 4 s. The VO2mus changes were also monitored by near-infrared spectroscopy with continuous wave. The VO2mus during exercise was expressed relative to the resting value. The resting metabolic rate, calculated from the PCr breakdown rate after complete O2 depletion, was 0.0010 (SD) mM ATP/s. During submaximal exercise (pH > 6.9), the VO2mus increased with a rise in intensity (0.036 +/- 0.011, 0.054 +/- 0.016, 0.062 +/- 0.012, and 0.067 +/- 0.020 mM ATP/s during 10, 20, 30, and 40% maximal voluntary contraction, respectively) and showed significant correlation with changes in both calculated ADP and PCr values (r2 = 0.98 and r2 = 0.99, respectively). In conclusion, because of the significant correlation with regulatory metabolites (ADP and PCr) of oxidative phosphorylation, O2 decline rate in immediate postexercise ischemia determined by near-infrared spectroscopy with continuous wave can be utilized for the quantitative evaluation of localized muscle oxidative metabolism.

Adult↗
PubMed1996

[Surgical correction of total anomalous pulmonary venous drainage: an adult case of successful repair].

Total anomalous pulmonary venous drainage (TAPVD) is a rare congenital cardiac anomaly. It occurs in only 1.5% of children born with congenital heart defects. But, it is one of the most common lesions necessitating intracardiac operation in the neonatal period. We have experienced a 33-year-old man with supracardiac type TAPVD who was operated upon successfully. Cardiac catheterization showed 0.35 in Pp/Ps, 3.33 in Qp/Qs and 0.11 in Rp/Rs. The left to right shunt ratio was 77%, while the right to left shunt ratio was 23%. The operation was composed of anastomosis between the left atrium and the common pulmonary vein, patch closure of the atrial septal defect, ligation of the vertical vein and tricuspid annuloplasty. The posterior approach was adopted in anastomosis between the left atrium and the common pulmonary vein. The association of a normal pulmonary vascular resistance, a large interatrial communication and absence of a pulmonary venous obstruction was considered as factors of a favorable result.

Adult↗
PubMed1995

[A case of primary mediastinal germ cell tumor, successfully treated with chemotherapy and curative resection].

A 20-year-old man was admitted to our hospital because of an abnormal shadow on chest X-ray Laboratory data revealed a high serum alpha-fetoprotein (AFP) and LDH level. Percutaneous needle biopsy of the tumor suggested primary mediastinal germ cell tumor. Curative resection was performed after three courses of combination chemotherapy (cis-platinum, VP-16, bleomycin and adriamycin). A post-operative histological examination of the mass revealed total necrosis. Post-operative course was uneventful, and he has been free of recurrence for the last six months.

Adult↗
PubMed1995

[A case of thymic squamous cell carcinoma successfully treated with curative resection].

A case of rare thymic squamous cell carcinoma was reported. A 46-year-old female was admitted to our hospital because of an abnormal shadow on chest X-ray. Chest CT showed anterior mediastinal tumor and histological diagnosis of squamous cell carcinoma was made by needle biopsy under CT guide. Esophagus and lung were no abnormal findings, we thought the primary region was thymus. On mid-sternotomy, anterior mediastinal tumor was resected with thymus, right phrenic nerve and pericardium, however it was not direct invasion to heart, great vessels, lung and chest wall. Resection of peripheral fatty tissue and dissection of mediastinal lymph nodes as much as possible, it was not capsular invasion and mediastinal lymph nodes metastasis and complete curative resection was able to perform. Additional radiation therapy was done, post-operative course was uneventful.

Carcinoma, Squamous Cell↗
PubMed1994

[Clinical study of aortitis syndrome].

Aortitis syndrome (Takayasu arteritis) is found frequently in Japan and it affects often young female. It was reported first by Takayasu in 1908 and thereafter many studies were performed about this disease. Consequently, it became clear that this is chronic inflammatory disease of unknown origin and it affects thoracic aorta, abdominal aorta, its branches and pulmonary artery, the lesion of which may show occlusion or dilatation. It shows many various symptoms and physical findings, which are pulselessness and vascular bruit at lesion etc., serum inflammatory reaction and angiography are important for its diagnosis. Medical control for inflammation at active phase and necessary surgical treatment at stable phase are the principle for its treatment.

Female↗
PubMed1994

[Reoperation after open mitral commissurotomy for mitral stenosis].

Between 1975 and 1993, 16 of 95 patients who received open mitral commissurotomy for mitral stenosis required reoperation for recurrent mitral lesions with a mean duration of 11 years after the initial operation at Kawasaki Medical School Hospital. The mitral lesions necessitating reoperation involved restenosis in eight, stenoinsufficiency in six and regurgitation in two. In 13 patients, mitral commissure was well separated, and the mitral restenosis and regurgitation were caused by progressions of valvular and subvalvular lesions. Significant tricuspid valve regurgitation was also seen in nine patients, and in seven out of eight patients who were in NYHA functional class III or IV, tricuspid regurgitation of grade 3 was observed. The combined tricuspid regurgitation aggravated the patient's symptoms and became a major risk factor of the reoperation after open mitral commissurotomy.

Catheterization↗