Search PubMed⌕ Search

Biomedical subjects

A Koike

Publications and source records attributed to A Koike.

At least 109 records · Page 6Linked to original sources

Evidence that the metabolic acidosis threshold is the anaerobic threshold.

We evaluated maximal O2 uptake (VO2max), the metabolic acidosis threshold determined by the V-slope analysis [plot of CO2 output (VCO2) as a function of oxygen uptake (VO2)], the ratio of increase in VO2 to work rate increment (delta VO2/delta WR), the upper slope (S2) of the V-slope analysis, and the VO2 for work below and above the metabolic acidosis threshold to determine whether the changes in O2 transport caused by increased carboxyhemoglobin (HbCO) affected these parameters and variables. Ten normal subjects (aged 32.8 +/- 7.1 yr) performed symptom-limited incremental exercise tests in a ramp pattern on a cycle ergometer while breathing air and air with added carbon monoxide to cause HbCO to be approximately 11% and 20%. VO2max decreased by 11.6 and 19.3%, the metabolic acidosis threshold decreased by 11.9 and 19.6%, delta VO2/delta WR decreased by 8.9 and 14.0%, and S2 increased by 13.6 and 21.8% when HbCO was increased to 11 and 20%, respectively. Most importantly, VO2 was unchanged related to work rate below the metabolic acidosis threshold during the tests with increased HbCO but was reduced at the work rates above the metabolic acidosis threshold. These findings are consistent with the concept that the metabolic acidosis threshold is synonymous with an anaerobic threshold, i.e., the latter demarcating the VO2 above which the contracting muscles are not adequately supplied with O2 but below which they are.

Acidosis↗

Evidence that diffusion limitation determines oxygen uptake kinetics during exercise in humans.

To determine the role of arterial O2 content on the mechanism of muscle O2 utilization, we studied the effect of 2, 11, and 20% carboxyhemoglobin (COHb) on O2 uptake (VO2), and CO2 output (VCO2) kinetics in response to 6 min of constant moderate- and heavy-intensity cycle exercise in 10 subjects. Increased COHb did not affect resting heart rate, VO2 or VCO2. Also, the COHb did not affect the asymptotic VO2 in response to exercise. However, VO2 and VCO2 kinetics were affected differently. The time constant (TC) of VO2 significantly increased with increased COHb for both moderate and heavy work intensities. VO2 TC was positively correlated with blood lactate. In contrast, VCO2 TC was negatively correlated with increased COHb for the moderate but unchanged for the heavy work intensity. The gas exchange ratio reflected a smaller increase in CO2 stores and faster VCO2 kinetics relative to VO2 with increased COHb. These changes can be explained by compensatory cardiac output (heart rate) increase in response to reduced arterial O2 content. The selective slowing of VO2 kinetics, with decreased blood O2 content and increased cardiac output, suggests that O2 is diffusion limited at the levels of exercise studied.

Adolescent↗

Effects of isosorbide dinitrate on exercise capacity in cardiac patients--relationship between oxygen uptake responses and hemodynamic effects.

Acute effects of oral isosorbide dinitrate on exercise capacity were evaluated in 14 patients with chronic heart disease measuring the anaerobic threshold and left ventricular function during exercise. A symptom-limited exercise test was performed on a bicycle ergometer with work rates increased by 1W every 6 seconds. Left ventricular function was continuously monitored with a computerized cadmium telluride detector following the intravenous injection of technetium-labeled red blood cells. Thirty minutes after the control exercise test, patients were given isosorbide dinitrate, 5 mg orally. The second exercise test was performed 30 min later. Isosorbide dinitrate improved the anaerobic threshold from 715.4 +/- 172.9 to 774.9 +/- 173.5 ml/min (p less than 0.01) and ejection fraction at peak exercise from 36.7 +/- 11.6 to 39.9 +/- 12.3% (p less than 0.05). However, there was no significant change in maximum work rate or peak oxygen uptake. Those patients for whom isosorbide dinitrate resulted in a 10% or greater improvement in the anaerobic threshold had both higher pre-treatment ejection fractions and greater increases in peak exercise ejection fraction following isosorbide dinitrate. Measurements of the anaerobic threshold and left ventricular function during exercise may be useful in the evaluation of the efficacy of vasodilators in cardiac patients.

Anaerobiosis↗

[A case of ruptured azygos vein and diaphragmatic hernia due to blunt chest trauma].

A 47-year-old female was admitted to the emergency room following an automobile accident. She was shocked complaining of respiratory difficulty and chest pain. A chest X-ray showed right hemothorax which drained 2.5 liters of blood on insertion of chest tube. Emergency operation revealed rupture of azygos vein. The bleeding was controlled by the ligation of the azygos vein. Postoperative chest X-ray showed obscuration of the left diaphragma, and herniated stomach was identified by the gastrography. Second operation was performed and ruptured diaphragma was repaired. Her postoperative recovery was good. She was discharged from hospital at 7th week.

Azygos Vein↗

[Application of an extended aortic arch anastomosis for staged repair of type A interruption: a case report of a 13-day-old neonate].

A 2-day-old girl was found to have a type A interruption of aortic arch, ventricular septal defect and patent ductus arteriosus with severe metabolic acidosis. Following aggressive medical treatment with Prostaglandin E1 and inotropic agents, she underwent arch reconstruction by extended aortic arch anastomosis and pulmonary arterial banding on her 13th day. Six months after first stage repair, a subarterial infundibular VSD was closed transpulmonary and reconstruction of pulmonary artery was done by end-to-end anastomosis. She shows normal development, strong femoral pulse and no neurologic sequelae after 8 months postoperatively.

Aorta, Thoracic↗

Evaluation of severity of heart failure using ventilatory gas analysis.

To evaluate the severity of heart failure, cardiopulmonary exercise testing was performed in 99 normal subjects and in 382 patients with cardiac disease. Anaerobic threshold, peak oxygen uptake, and the ratio of increase in oxygen uptake to work-rate increment were determined by ventilatory and gas exchange measurements as indexes for assessing the severity of heart failure. Anaerobic threshold and peak oxygen uptake declined with age, and males showed higher values than females in both indexes. Anaerobic threshold, as the percentage of predicted value for age, sex, and body weight, decreased as New York Heart Association (NYHA) class increased as follows: 90.2 +/- 15.4% in class I, 76.9 +/- 13.8% in class II, and 59.7 +/- 11.9% in class III (mean +/- SD). Although the ratio of increase in oxygen uptake to work-rate increment was not influenced by age or sex, it decreased as the severity of heart disease progressed. These results suggest that indexes from cardiopulmonary exercise testing are closely related to the pathophysiology of heart failure. We conclude that these indexes can be used as objective and reliable parameters for evaluation of the severity of heart failure in terms of functional capacity.

Anaerobic Threshold↗

[Efficacy of a 48-hour infusion of 5-fluorouracil in patients with stage IV gastric cancer after palliative gastrectomy].

Efficacy of a 48-hour infusion of 5-FU in patients with stage IV gastric cancer was investigated. A one-cycle regimen consisted of a 48-hour infusion of 5-FU (30 mg/kg/24 hours) every week for 6 weeks. Fourteen patients with stage IV gastric cancer who underwent absolutely non-curative gastrectomy, received 5-FU infusion postoperatively. Ten of the 14 received more than 2 cycles. Survival rates in these patients (group I) were evaluated by Kaplan-Meier method and compared with those of matched pair controls (group II) who received other anticancer agents. Side effects were generally mild. Nausea during infusion was observed in only 3 cases. The 50% survival period was 393 days in group I and 135 days in group II, respectively. The survival curve in group I was significantly higher than in group II (p = 0.05). From these results, this treatment is considered to be very effective.

Aged↗

[Case report of a saccular aneurysm of the thoracic aorta in childhood].

A five-year-old boy with a large saccular aneurysm of the thoracic descending aorta extending rightward in the mediastinum underwent operation. Through a left thoracotomy descending aorta was clamped during partial femoro-femoral bypass and a examination of somatosensory evoked potential of the spinal cord. Placing a vertical incision on the aorta, a orifice of the aneurysm was closed with a xenograft pericardial patch. The aneurysm was left untouched. Nine months after operation the aneurysm was not recognized on chest X-ray and computed tomography. Etiology was unknown.

Aorta, Thoracic↗

Clear cell carcinoma of the thyroid. A case report.

A rare case of clear cell carcinoma of the thyroid is presented herein. A 31-year-old male had a large soft tumor in the right lobe of the thyroid which showed a hot nodule on scintigram with 99mTc. A right hemithyroidectomy was thus performed after the preoperative diagnosis of a functioning tumor had been made. At surgery, a tiny nodule behind the tumor was found and the histopathological diagnoses of the large tumor and the tiny nodule were clear cell carcinoma and papillary carcinoma, respectively. The thyroglobulin stain was positive in the cytoplasm of many clear cells and scattered colloid. This patient has been well without any evidence of recurrence over the past five years following surgery. The biological characteristics of clear cell carcinoma of the thyroid are discussed in this report.

Adenocarcinoma↗

Detecting abnormalities in left ventricular function during exercise by respiratory measurement.

The degree of exercise-induced cardiac dysfunction and its relation to the anaerobic threshold were evaluated in 23 patients with chronic heart disease. A symptom-limited exercise test was performed with a cycle ergometer with work rate increased by 1 W every 6 seconds. Left ventricular function, as reflected by ejection fraction, was continuously monitored with a computerized cadmium telluride detector after the intravenous injection of technetium-labeled red blood cells. The anaerobic threshold (mean, 727 +/- 166 ml/min) was determined by the noninvasive measurement of respiratory gas exchange. As work rate rose, the left ventricular ejection fraction increased but reached a peak value at the anaerobic threshold and then fell below resting levels. Ejection fraction at rest, anaerobic threshold, and peak exercise were 41.4 +/- 11.3%, 46.5 +/- 12.0%, and 37.2 +/- 11.0%, respectively. Stroke volume also increased from rest (54.6 +/- 17.0 ml/beat) to the point of the anaerobic threshold (65.0 +/- 21.2 ml/beat) and then decreased at peak exercise (52.4 +/- 18.7 ml/beat). The slope of the plot of cardiac output versus work rate decreased above the anaerobic threshold. The anaerobic threshold occurred at the work rate above which left ventricular function decreased during exercise. Accurate determination of the anaerobic threshold provides an objective, noninvasive measure of the oxygen uptake above which exercise-induced deterioration in left ventricular function occurs in patients with chronic heart disease.

Anaerobic Threshold↗

Severity and pathophysiology of heart failure on the basis of anaerobic threshold (AT) and related parameters.

Cardio-pulmonary exercise testing was performed in 99 normal subjects and 382 patients with cardiac disease in order to evaluate anaerobic threshold (AT) and related parameters as indices for assessing the severity of heart failure. AT could be determined easily during ergometer exercise testing with ramp protocol by monitoring minute ventilation (VE), oxygen uptake (VO2) and carbon dioxide output (VCO2). Peak VO2 and the ratio of VO2 rising to work rate increment (delta VO2/delta WR) were also determined. There was good correlation between the AT determined by respiratory measurement and that determined by arterial lactic acid concentration (r = 0.93, n = 15). The reproducibility of AT was excellent between 2 testings with a 3-hour interval. AT (ml/min/kg) and peak VO2 (ml/min/kg) declined with age, and males showed higher values than females in both indices. %AT, determined by the predicted AT values of each age and sex, decreased as NYHA class progressed as follows: 90.2 +/- 15.4% in class I, 76.9 +/- 13.8% in class II, and 59.7 +/- 11.9% in class III. Although delta VO2/delta WR was not influenced by age or sex, it also decreased as the severity of heart disease progressed. These results suggest that indices from cardiopulmonary exercise testing, especially AT, are closely related to the pathophysiology of heart failure, so that they are objective and reliable parameters for evaluation of the severity of heart failure and are sensitive enough to detect the efficacy of therapeutic intervention for heart failure.

Adolescent↗

[Refractory anemia with ringed sideroblasts complicated with delta beta-thalassemia-like hemoglobinopathy].

A 73 year-old man suffering from marked anemia for several years admitted in our hospital. Diagnosis was immediately made of refractory anemia with ringed sideroblasts by the existence of ringed sideroblasts. Hemoglobin analysis revealed a high fetal hemoglobin, a low hemoglobin A2, a decreased beta/alpha synthetic ratio, and a decreased G gamma/A gamma synthetic ratio. This acquired hemoglobinopathy resembled delta beta-thalassemia. His anemia was remarkably improved because of the responsiveness to anabolic steroid hormone, and this abnormal globin synthetic pattern was identical as those of the normal adult. We consider this hemoglobinopathy may due to an abnormal expression of globin mRNA.

Aged↗

[Vasodilator therapy utilizing nitroprusside and nitroglycerin after coronary artery surgery].

The hemodynamic effects of combined therapy utilizing sodium nitroprusside (SNP) and nitroglycerin (TNG) were compared with those of TNG therapy in patients who underwent coronary artery bypass grafting (CABG). Of 58 patients who received catecholamine infusion to maintain hemodynamics after CABG, 17 had perioperative myocardial infarction (PMI (+) cases) and the other 41 had not PMI (PMI (-) cases). 26 of 41 patients (PMI (-) cases) received nitroglycerin therapy (NTG group) and the other 15 patients received combined therapy (SNP + NTG group). 11 of 17 patients (PMI (+) cases) received NTG therapy and the other 6 patients received combined therapy. The hemodynamic valuables, which were studied, were as follows; cardiac index, stroke volume index, left ventricular stroke work index, systemic vascular resistance index, pulmonary vascular resistance index, and deep core temperature. SNP + TNG group revealed significantly lower systemic vascular resistance index and pulmonary vascular resistance index than TNG group in PMI (-) cases. In PMI (+) cases, SNP + TNG group revealed significantly higher cardiac index, stroke volume index, left ventricular stroke work index, and significantly lower pulmonary vascular resistance index than TNG group. These findings demonstrate that combined therapy can obtain more secure vasodilation than TNG therapy.

Cardiac Output, Low↗

[An effect of adjuvant immunochemotherapy using krestin and 5-FU on gastric cancer patients with radical surgery (first report)--a randomized controlled trial by the cooperative study group. Study Group of Immuno-chemotherapy with PSK for Gastric Cancer].

To evaluate the efficacy of PSK for adjuvant immuno-chemotherapy in patients who had undergone radical gastrectomy, a randomized controlled trial has been in progress in collaboration with 46 institutions in the Chubu district of Japan. A total of 262 patients were registered for this trial during the two years from July 1985 to June 1987 with a centralized registration system, and were allocated into the 5-FU+PSK group (Group P) and 5-FU alone group (Group C) by the minimization method following the random permuted blocks method. Between the two groups, the parameters of sex, age, serosal invasion (S), lymph-node metastasis (N), and the combination of S . N factor levels were distributed without significant differences. An induction treatment with MMC 6 mg/m2 was given to all patients following curative gastrectomy and on the 7th post-operative day. Two weeks after surgery, Group P received alternately PSK 3 g/day for 4 week and 5-FU 150 mg/day for 4 weeks as one course, and 10 courses were given. Group C received 5-FU alone for 4 weeks using alternate rest interval for 4 weeks. Since both experimental and clinical studies suggested that alternate treatments using PSK and anticancer agents were effective, treatment in this trial alternated PSK and 5-FU. A final follow-up study will be completed in June 1992, when all patients shall have survived more than 5 years after surgery. The administration of 5-FU was completed by January. 1989, but PSK has been administered to group P. The period from 18 to 42 months after surgery was reached in all eligible patients (253) at the end of December 1988. The disease-free survival curves and overall survival curves of group P were significantly (p = 0.018 and p = 0.045,) better than those of group C.

Adjuvants, Immunologic↗

[Result of surgical treatment to benign thyroid tumor].

Surgical results of 81 cases with various benign thyroid tumors were reviewed. All had undergone mainly hemi-lobectomy including isthmectomy and had been followed up for more than 2 years. Sixty-eight (84%) have been well without any complaint. However, 5 of 15 cases with adenomatous goiter (AG) again developed nodule(s) in the remnant thyroid and 1 of 37 cases with adenoma developed cancer in the remnant. In order to prevent recurrence in the cases with AG, total thyroidectomy may be required with the meticulous selection of the case. For the cases with AG which undergone hemilobectomy or lumpectomy, TSH suppression treatment may be also required after surgery. It is of caution that the nodule developed in the thyroid after surgery may be not always the same nodule as primary one.

Adult↗

[A case report of successful repair for ruptured aneurysm of sinus of Valsalva (I VSD) with aortic regurgitation].

A nineteen-year-old female who had history of infectious endocarditis underwent surgical repair for ruptured aneurysm of sinus of Valsalva with aortic regurgitation. Through aortotomy mild degree of prolapse of right coronary cusp and perforation of left coronary cusp sized 6 mm in diameter were recognized and the latter was thought to be the dominant lesion resulting in severe aortic regurgitation. Following direct closure of ruptured aneurysm and patch closure of ventricular septal defect, perforated left coronary cusp was repaired with autologous pericardium. Post operative course was uneventful and she is now doing well.

Adult↗