Biomedical subjects

Takeshi Ogawa

Publications and source records attributed to Takeshi Ogawa.

11 recordsLinked to original sources

PubMed2006

Metabolic response during intermittent graded sprint running in moderate hypobaric hypoxia in competitive middle-distance runners.

The purpose of this study was to determine whether the metabolic response and running performance during intermittent graded sprint running were affected by moderate hypobaric hypoxia (H; 2,500 m above sea level) in competitive middle-distance runners. Nine male runners performed intermittent graded sprint running until exhaustion, to evaluate the metabolic response and running performance in H and normobaric normoxia (N). The test constructed of incremental (25 m min(-1)) 20 s running bouts (4 degrees inclination) interspaced with 100 s recovery periods. Maximal running speed was not different between conditions [453 (7) m min(-1) vs. 458 (4) m min(-1) in N vs. H]. V(O2) at each speed was lower in H than N (ANOVA; P < 0.05). Although, oxygen deficit (D(O2)) at each speed was not different between N and H (ANOVA; P = 0.1), total accumulated D(O2) in all bouts was significantly higher in H than N [165 (10) ml kg(-1) in N and 173 (10) ml kg(-1) in H]. The ratio of D(O2).V(O2)(-1) was similar in all bouts, but higher in H than N. These results suggest that intermittent graded sprint running performance is not affected by moderate hypobaria despite a reduction in the energy supplied by aerobic metabolism due to a compensatory increase in the energy supplied by the anaerobic metabolism in competitive middle-distance runners.

Adult↗

PubMed2005

Relationship between ventilatory response and body temperature during prolonged submaximal exercise.

We examined whether an increase in skin temperature or the rate of increase in core body temperature influences the relationship between minute ventilation (Ve) and core temperature during prolonged exercise in the heat. Thirteen subjects exercised for 60 min on a cycle ergometer at 50% of peak oxygen uptake while wearing a suit perfused with water at 10 degrees C (T10), 35 degrees C (T35), or 45 degrees C (T45). During the exercise, esophageal temperature (Tes), skin temperature, heart rate (HR), Ve, tidal volume, respiratory frequency (f), respiratory gases, blood pressure (BP), and blood lactate were all measured. We found that oxygen uptake, carbon dioxide output, BP, and blood lactate did not differ among the sessions. Tes, HR, Ve, and f remained nearly constant from minute 10 onward in the T10 session, but all of these parameters progressively increased in the T35 and T45 sessions, and significantly higher levels were seen in the T45 than the T35 session. For all but two subjects in the T35 and T45 sessions, plotting Ve as a function of Tes revealed no threshold for hyperventilation; instead, increases in Ve were linearly related to Tes, and there were no significant differences in the slopes or intercepts between the T35 and T45 sessions. Thus, during prolonged submaximal exercise in the heat, Ve increases with core temperature, and the influences of skin temperature and the rate of increase in Tes on the relationship between Ve and Tes are apparently small.

Adult↗

PubMed2005

Intermittent short-term graded running performance in middle-distance runners in hypobaric hypoxia.

This study investigated whether in trained middle-distance runners, intermittent short-term graded running performance is affected by a hypobaric hypoxic environment (simulated 2,500 m) (H). Seven male middle-distance runners performed an aerobic performance test and an intermittent short-term graded anaerobic running-performance test (MART) both in H and in a normobaric normoxic environment (N). VO(2max) and OBLA were markedly lower (by 18.1% and 8.7%, respectively) in H than in N. In MART, neither maximal running velocity (V(max)) nor exhaustion-time was different between N and H (454 (7) m min(-1) vs. 451 (6) m min(-1), respectively, and 208.7 (5.2) s vs. 205.7 (4.2) s, respectively). The blood lactate concentration at sub-maximal running speed (425 m min(-1)) was significantly greater in H than in N (paired t-test: P<0.05). These results suggest that, in trained middle-distance runners, intermittent short-term graded running performance is not affected by H, despite a considerable decrease in aerobic power in H during the aerobic performance test.

Adult↗

PubMed2005

Alteration of gene expression in intervertebral disc degeneration of passive cigarette- smoking rats: separate quantitation in separated nucleus pulposus and annulus fibrosus.

OBJECTIVE: We constructed a passive cigarette-smoking model with rats to investigate the molecular mechanism of intervertebral disc degeneration, and found by gene expression analysis that passive cigarette smoking stimulated the stress-responsive signal pathway and inhibited the apoptotic pathway. In this study, to clarify that these changes were derived from either nucleus pulposus (NP) or annulus fibrosus (AF), we separately collected NP and AF and quantitatively analyzed gene expression. METHODS: Total RNA was extracted from NP and AF of the lumbar intervertebral discs from rats which were kept in a smoking box for 4 and 8 weeks. Gene expression was measured by real-time PCR of cDNA synthesized from the total RNA. RESULTS: Stress-responsive protein, heat shock protein 70, was expressed similarly in NP and AF, and was upregulated to the same degree after 8 weeks of passive cigarette smoking. The protein tyrosine phosphatase gene was expressed more strongly in AF than in NP, and was upregulated after 8 weeks of smoking in both tissue parts. The type II collagen and aggrecan genes were predominantly expressed in AF and NP, respectively. CONCLUSION: These results indicate that passive cigarette smoking stimulates both NP and AF, and induces the stress-responsible genes such as heat shock protein 70 and protein tyrosine phosphatase in both.

Aggrecans↗

PubMed2004

Effects of brief leg cooling after moderate exercise on cardiorespiratory responses to subsequent exercise in the heat.

We investigated the effects of brief leg cooling after moderate exercise on the cardiorespiratory responses to subsequent exercise in the heat. Following 40 min of ergometer cycling [65% peak oxygen uptake (VO(2peak))] at 35 degrees C (Ex. 1), seven male subjects [21.9 (1.1) years of age; 170.9 (1.9) cm height; 66.0 (2.0) kg body mass; 46.7 (2.0) ml kg(-1) min(-1) VO(2peak)] immersed their legs in 35 degrees C (control condition, CONT) or 20 degrees C (cooling condition, COOL) water for 5 min and then repeated the cycling (as before, but for 10 min) (Ex. 2). Just before Ex. 2, esophageal temperature ( T(es)) was lower in COOL than in CONT [36.9 (0.2) vs 37.5 (0.1) degrees C] ( P<0.01), as also were both mean skin temperature [33.9 (0.2) vs 35.2 (0.2) degrees C] ( P<0.01), and heart rate (HR) [93.2 (6.0) vs 102.7 (4.9) beats min(-1)] ( P<0.05). During Ex. 2, no differences between CONT and COOL were observed in oxygen uptake, arterial blood pressure, blood lactate concentration, or ratings of perceived exertion; however, T(es), skin temperature, and HR were lower in COOL than in CONT. Further, during the first 5 min of Ex. 2, minute ventilation was significantly lower in COOL than in CONT [50.3 (2.0) vs 53.4 (2.6) l min(-1)] ( P<0.01). These results suggest that brief leg cooling during the recovery period may be effective at reducing thermal and cardiorespiratory strain during subsequent exercise in the heat.

Adult↗

PubMed2004

Relationship among prevalence of patients with Itai-itai disease, prevalence of abnormal urinary findings, and cadmium concentrations in rice of individual hamlets in the Jinzu River basin, Toyama prefecture of Japan.

This study investigated the associations among prevalence of patients with Itai-itai disease, and prevalence of abnormal urinary findings and cadmium (Cd) concentrations in rice in individual hamlets of the Jinzu River basin. From the 13,183 participants of the 1967 and 1968 health examinations, we selected 3,094 subjects as the target population who had resided in the current hamlet for a total of 30 years or longer and aged >/=50 years, and in the hamlet both the Cd concentration in rice and prevalence of patients with Itai-itai disease were known. When the inhabitants were divided into four groups according to the Cd concentration in rice or prevalence of abnormal urinary findings, significant relationships among three factors (Cd concentration in rice, prevalence of abnormal urinary findings and prevalence of patients with Itai-itai disease) were demonstrated clearly using the Cochran-Armitage test. Correlation coefficients among the three factors in 55 hamlets showed that the prevalence of the patients with Itai-itai disease increased according to increases in the mean Cd concentration in rice and increasing prevalence of urinary findings. This study demonstrated that Itai-itai disease is induced by exposure to environmental Cd and that renal dysfunction plays an important role in its development.

Aged↗

PubMed2004

Modulation of control of muscle sympathetic nerve activity during orthostatic stress in humans.

We tested the hypothesis that orthostatic stress would modulate the arterial baroreflex (ABR)-mediated beat-by-beat control of muscle sympathetic nerve activity (MSNA) in humans. In 12 healthy subjects, ABR control of MSNA (burst incidence, burst strength, and total activity) was evaluated by analysis of the relation between beat-by-beat spontaneous variations in diastolic blood pressure (DAP) and MSNA during supine rest (CON) and at two levels of lower body negative pressure (LBNP: -15 and -35 mmHg). At -15 mmHg LBNP, the relation between burst incidence (bursts per 100 heartbeats) and DAP showed an upward shift from that observed during CON, but the further shift seen at -35 mmHg LBNP was only marginal. The relation between burst strength and DAP was shifted upward at -15 mmHg LBNP (vs. CON) and further shifted upward at -35 mmHg LBNP. At -15 mmHg LBNP, the relation between total activity and DAP was shifted upward from that obtained during CON and further shifted upward at -35 mmHg LBNP. These results suggest that ABR control of MSNA is modulated during orthostatic stress and that the modulation is different between a mild (nonhypotensive) and a moderate (hypotensive) level of orthostatic stress.

Adult↗

PubMed2004

Ongoing myocardial damage in chronic heart failure is related to activated tumor necrosis factor and Fas/Fas ligand system.

BACKGROUND: Elevated concentrations of cardiac troponin T and heart-type fatty acid-binding protein (H-FABP) identify patients with chronic heart failure (CHF) and ongoing myocardial damage (OMD) who are at increased risk for future cardiac events. Cardiomyocyte necrosis and/or apoptosis via activated tumor necrosis factor (TNF) and the Fas/Fas ligand (FasL) system may be related to the development of OMD. METHODS AND RESULTS: The serum concentrations of H-FABP, a sensitive marker of membrane damage of cardiomyocytes, soluble Fas (sFas) and TNF-alpha were measured in 38 patients with CHF. The concentrations of H-FABP, TNF-alpha and s-Fas in patients with New York Heart Association (NYHA) III + IV were all significantly higher than in those patients in NYHA II (H-FABP; III + IV 9.3+/-5.9 vs II 5.1+/-1.8 ng/ml, p=0.003, TNF-alpha; III + IV 10.5+/-3.8 vs II 8.0+/-2.7 pg/ml, p=0.02, sFas; III + IV 3.36+/-1.37 vs II 2.58 +/-0.84 ng/ml, p=0.03). Increased concentrations of H-FABP significantly correlated with the concentrations of TNF- alpha (r=0.57, p=0.0001) and sFas (r=0.69, p<0.0001), independent of renal function. CONCLUSION: OMD detected by H-FABP, a marker of membrane damage, is related to activated TNF and the Fas/FasL system, which suggests a pathophysiological role of cardiomyocyte necrosis and/or apoptosis in patients with worsening heart failure.

Aged↗

PubMed2003

Superior mesenteric arterial embolism: treatment by trans-catheter thrombo-aspiration.

A 57-year-old woman with hypertension, mixed mitral valve disease, and atrial fibrillation was admitted to our hospital because of abdominal pain continuing for several hours. On the following day, colonoscopy was performed, and diffuse yellow-white pseudomembranous changes were seen in the right hemicolon, but there were no abnormal findings in the left hemicolon; 24 h after onset, a diagnosis of superior mesenteric arterial embolism was made on the computed tomography (CT) scan findings. Abdominal angiography was performed and showed complete occlusion of the superior mesenteric artery (SMA). Then conservative treatment, using per-catheteric thrombus aspiration, was done, followed by intraarterial injection of tissue type plasminogen activator. After the thrombo-aspiration, the filling deficit of the main artery had disappeared, and the branches on the right side were clearly delineated. After the treatment, the symptoms such as abdominal pain and diarrhea improved accordingly. She was discharged from the hospital 27 days later. Our case suggests that trans-catheter thrombo-aspiration is a possible alternative to open embolectomy for some cases of SMA embolism more than 10 h post-onset.

Catheterization↗

PubMed2002

Use of cytosolic and myofibril markers in the detection of ongoing myocardial damage in patients with chronic heart failure.

PURPOSE: Measurement of serum levels of cytosolic and myofibril components of cardiac tissue could indicate ongoing myocardial damage in patients with chronic heart failure. METHODS: We correlated serum levels of a cytosolic marker (heart-type fatty acid-binding protein) and a myofibril marker (troponin T) with the severity of symptoms (based on the New York Heart Association [NYHA] class), neurohumoral derangement, and subsequent cardiac events in 56 patients with chronic heart failure. RESULTS: Mean (+/- SD) levels of heart-type fatty acid-binding protein were greater in patients with NYHA class III or IV heart failure (9.9 +/- 5.2 ng/mL) than in those with NYHA class II (4.9 +/- 1.9 ng/mL, P <0.0001). Detection of troponin T (> or =0.02 ng/mL) was also more common in patients with worse heart failure (81% [13/16] in class III or IV vs. 43% [17/40] in class II, P = 0.02). Significant correlations were found between heart-type fatty acid-binding protein levels and plasma levels of A-type natriuretic peptide (r = 0.45, P = 0.0004), B-type natriuretic peptide (r = 0.66, P <0.0001), and norepinephrine (r = 0.36, P = 0.006). Male sex (hazard ratio [HR] = 5.0; 95% confidence interval [CI]: 1.3 to 19), detectable troponin T levels (HR = 7.0; 95% CI: 1.1 to 44), heart-type fatty acid-binding protein (HR = 2.6 per 3.9-ng/mL increase; 95% CI: 1.1 to 6.5), and left ventricular ejection fraction (HR = 3.6 per 15% decrease; 95% CI: 1.2 to 11) were independently associated with subsequent cardiac events (8 deaths or 10 readmissions because of worsening heart failure). CONCLUSION: Heart-type fatty acid-binding protein and troponin T are markers of ongoing myocardial damage, and are associated with subsequent cardiac events in patients with chronic heart failure.

Aged↗

PubMed2001

Cavernous Pancreatic Ductal Ectasia with Smooth Muscle Proliferation Causing Recurrent Acute Pancreatitis.

Pancreatic cystic lesions have various etiologies,including pseudocyst (inflammatory cyst), retentioncyst, congenital cyst, and neoplastic cyst (1).Recently, we experienced a case with a uniquepancreatic cyst-like lesion causing recurrent acutepancreatitis. This patient had multiple cystic dilatations of branch pancreatic ducts surrounded by proliferationof smooth muscle tissue, with neither neoplastic nor inflammatory changes. To our knowledge, there are no previous reports of such a case.

Journal Article↗