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Biomedical subjects

A Koike

Publications and source records attributed to A Koike.

At least 55 records · Page 3Linked to original sources
PubMed1996

Time- versus frequency-domain analysis in predicting cycle length of inducible ventricular tachycardia after myocardial infarction.

To determine whether time- and frequency-domain analyses differ in their ability to predict sustained ventricular tachycardia (VT) induced by programmed ventricular stimulation, 60 consecutive patients with myocardial infarction and 30 healthy control subjects were evaluated. Programmed ventricular stimulation using three extrastimuli and signal-averaged ECG recordings were performed in patients with myocardial infarction. Of the 60 patients, sustained monomorphic VT (SMVT) with cycle length (CL) > or = 250 ms (slow SMVT) was inducible in 9, and SMVT with CL < 250 ms (fast SMVT) was inducible in 9. The durations of the filtered QRS (f-QRS) at each high-pass filter (25, 40, and 80 Hz) and the low amplitude signal (LAS) at 25-Hz high-pass filtering were significantly longer in the slow SMVT group than in the fast SMVT, no VT, or normal control group. The root-mean-square voltages at 25-Hz and 80-Hz high-pass filters in the slow SMVT group were significantly lower than in the fast SMVT, no VT, or normal control group. There was no significant difference in time-domain variables among fast SMVT, no VT, and normal control groups. The CL of the induced sustained VT was significantly correlated with the durations of f-QRS and LAS. Concerning frequency-domain variables (area ratio and factor of normality), there was no significant difference between slow and fast SMVT groups. Both the slow and fast SMVT groups had a significantly higher area ratio and a significantly lower factor of normality than the group with no VT or the normal control subjects. In conclusion, there were significant correlations between time-domain variables and CL of SMVT, while there was no correlation when using frequency-domain parameters.

Cardiac Catheterization↗
PubMed1996

Preserved musical abilities following right temporal lobectomy.

It has been widely accepted that the right temporal lobe plays a major role in the processing of music. One of the main lines of evidence was derived from Milner's study, published in 1962, which reported that right temporal lobectomy led to a decline in patient scores on four of the six subtests (Tonal Memory, Timbre, Loudness, and Time subtests) of the Seashore Measures of Musical Talents. That finding had led some surgeons and patients to hesitate in choosing right temporal lobectomy as a treatment for intractable epilepsy. The authors examined performance on the Seashore Measures before and after operations in 20 patients with right temporal lobectomy and nine patients with left temporal lobectomy. No disturbances in the Seashore Measures were detected after temporal lobectomy on either side. The extent of these temporal lobectomies was smaller than that of the temporal lobectomies in Milner's study, as measured along the sylvian fissure (1.5-4 cm; mean 2.7 cm, standard deviation (SD) 0.92 cm) and the base of the temporal lobe (3.5-5.5 cm; mean 4.7 cm, SD 0.63 cm). These findings indicate that the region resected on right temporal lobectomy in the present study is not essential for basic musical processing.

Adult↗
PubMed1996

[Serum eosinophil cationic protein in infants during first wheezing episode].

We measured serum ECP levels in infants during first wheezing episode. Serum ECP in these infants are significantly higher than in control infants, although much higher in children with asthma. Serum ECP in these infants with high serum IgE and/or positive RAST score are higher than in infants with normal serum IgE and negative RAST score. In children with bronchial asthma serum ECP is correlated with peripheral eosinophil counts, but in infants during first wheezing episode serum ECP is often elevated not associated with increased peripheral eosinophil counts. These suggest that activated eosinophils could be responsible for bronchoconstriction in wheezing patients with atopic diathesis even in very early phase and that these eosinophilic inflammations could contribute to formation of increased airway reactivity and bronchial asthma.

Asthma↗
PubMed1996

[Pseudoaneurysm].

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Aneurysm, False↗
PubMed1995

Effects of nicorandil on kinetics of oxygen uptake at the onset of exercise in patients with coronary artery disease.

The beneficial effects of coronary vasodilators on exercise capacity in patients with angina pectoris are well known. However, their effects on oxygen uptake (VO2) kinetics at the onset of exercise have not been elucidated. The present study was undertaken to determine the acute effects of nicorandil, a newer coronary vasodilator, on the kinetics of VO2 at the onset of exercise in patients with ischemic heart disease. Ten patients with significant coronary stenosis performed constant mild-intensity cycle exercise (32 +/- 3 W) for 6 minutes after oral administration of 10 mg of nicorandil or an identical placebo in a double-blind, crossover manner. Nicorandil had no effect on resting heart rate, blood pressure, or VO2. However, the time constant for the increase in VO2 during constant work rate exercise was significantly shorter (the kinetics of VO2 were faster) after administration of nicorandil than after placebo (46.5 +/- 13.3 vs 51.1 +/- 11.9 seconds; p = 0.039). The increase in VO2 at 6 minutes compared with 3 minutes of constant work, which reflects the VO2 kinetics, also was reduced with nicorandil (3.8 +/- 37.9 vs 27.5 +/- 27.1 ml/min; p = 0.022). Nicorandil was found to increase the rate of VO2, increase during the onset of constant work rate exercise, probably as a result of an improved response in cardiac output. Analysis of VO2 kinetics provides new and useful parameters for the evaluation of circulatory adjustments at the onset of exercise in patients with ischemic heart disease.

Adult↗
PubMed1995

Evaluation of exercise capacity using submaximal exercise at a constant work rate in patients with cardiovascular disease.

BACKGROUND: Symptom-limited incremental exercise tests are used to estimate the severity of cardiovascular disease and the patient's daily activity. However, there is a need for objective parameters for submaximal exercise. To test the hypothesis that a decrease in maximal exercise capacity can be estimated by oxygen uptake (VO2) kinetics, we measured the time constant of VO2 both during the onset of constant work rate exercise at 50 W and during recovery from this exercise and compared it with data obtained during maximal exercise in patients with cardiovascular disease and in normal subjects. METHODS AND RESULTS: A total of 34 patients with cardiovascular disease and 14 normal subjects performed 6 minutes of 50-W constant work rate exercise and an incremental exercise test to the symptom-limited maximum on a cycle ergometer. VO2 was calculated from respiratory gas analysis on a breath-by-breath basis. The time constant of VO2 during the onset of 50-W exercise was 61.4 +/- 15.2 seconds in patients with cardiovascular disease, significantly longer (the kinetics of VO2 were slower) than that in normal subjects (48.8 +/- 10.4 seconds, P = .008). The time constant of VO2 during the onset of exercise was significantly negatively correlated with peak VO2 (r = -.67) and maximal work rate (r = -.66). The time constant during recovery, which did not differ significantly from that of exercise, was also prolonged in patients with cardiovascular disease; it showed a negative correlation with peak VO2 (r = -.63) and maximum work rate (r = -.54). CONCLUSIONS: The time constant of VO2 during and after recovery from 50 W of constant work rate exercise, which does not require the subject's maximal effort, is a useful and objective measure of exercise capacity in patients with mild to moderate cardiovascular disease.

Adult↗
PubMed1995

[Exercise testing in cardiac patients].

Symptom-limited incremental exercise tests have been used, to estimate the severity of cardiovascular disease and the patients' daily activity. However, there is a considerable amount of interest in obtaining submaximal measurements of aerobic function rather than parameters requiring maximal exercise effort. We compared the parameters obtained during the incremental exercise with those during the 6 minutes of moderate constant work rate exercise. Peak oxygen uptake (VO2) and the anaerobic threshold were significantly decreased in patients with cardiovascular disease as compared to normal subjects. The slope of the increase in carbon dioxide output (VCO2) to the increase in VO2 (delta VCO2/delta VO2) above the anaerobic threshold was significantly increased and the slope of the increase in VO2 to the increase in work rate (delta VO2/delta WR) was significantly decreased in patients with cardiovascular disease. The anaerobic threshold was found to occur at the work rate above which left ventricular function decreased during exercise in these patients. The time constant of VO2 during and following recovery from 6 minutes of 50 watts of constant work rate exercise was significantly longer (the kinetics of VO2 were slower) in patients with cardiovascular disease than in normal subjects. The time constant of VO2 was significantly negatively correlated with peak VO2 and maximum work rate obtained during the incremental exercise.(ABSTRACT TRUNCATED AT 250 WORDS)

Anaerobic Threshold↗
PubMed1994

Efficacy of immunochemotherapy as adjuvant treatment after curative resection of gastric cancer. Study Group of Immunochemotherapy with PSK for Gastric Cancer.

In Japan the standard adjuvant treatment after resection of gastric cancer is intravenous mitomycin plus oral fluorouracil. We have assessed the efficacy of protein-bound polysaccharide (PSK) in addition to standard chemotherapy in patients who had undergone curative gastrectomy at 46 institutions in central Japan. 262 patients were randomly assigned standard treatment alone or with PSK. The minimum follow-up time was 5 years (range 5-7 years). PSK improved both the 5-year disease-free rate (70.7 vs 59.4% in standard treatment group, p = 0.047) and 5-year survival (73.0 vs 60.0%, p = 0.044). The two regimens had only slight toxic effects, consisting of nausea, leucopenia, and liver function impairment, and there were no significant differences between the groups. The treatments were clinically well tolerated and compliance was good. Addition of PSK to adjuvant chemotherapy with mitomycin and fluorouracil is beneficial as treatment after curative gastrectomy.

Adjuvants, Immunologic↗
PubMed1994

Prognosis after hepatic resection in patients with hepatocellular carcinoma, estimated on the basis of the morphometric indices.

To determine whether the morphometric indices of hepatocellular carcinoma (HCC) correlated with the prognoses, the microscopic morphometric values for 84 HCC cases treated by hepatic resection were studied using an image analyzer in relation to the survival rate and the gross classification. The mean survival time (MST) was 58 months in cases with a nucleocytoplasmic area ratio (N/C) of less than 0.28; this was significantly longer than the 38-month MST in cases with an N/C of more than 0.28 (P < 0.05). In stage III disease, the MST for cases with an N/C of less than 0.28 was 63 months, which was significantly longer than the MST of 13 months for cases with an N/C of more than 0.28. After relatively noncurative hepatic resection, the MST for cases with an N/C of less than 0.28 was 49 months, and this was significantly longer than the MST of 8 months for cases with an N/C of more than 0.28. The MST was 71 months for cases with a coefficient of variance of the nuclear form factor (NCV) of less than 5.5%, which was significantly longer than the MST of 33 months for cases with an NCV of more than 5.5% (P < 0.05). In stage III disease, the MST was 69 months for cases with an NCV of less than 5.5%, and this was significantly longer than the MST of 29 months for cases with an NCV of more than 5.5% (P < 0.05). In cases with an N/C of less than 0.28, 18% had vascular invasion and 38% had intrahepatic metastases, whereas in those with an N/C of more than 0.28, 62% had vascular invasion and 67% had intrahepatic metastases (P < 0.01, P < 0.05). Based on the results of these morphometric studies on HCC cases treated by hepatic resection, N/C and NCV may be useful as prognostic factors.

Carcinoma, Hepatocellular↗
PubMed1994

Critical capillary oxygen partial pressure and lactate threshold in patients with cardiovascular disease.

OBJECTIVES: The aim of this study was to determine the relation between femoral vein oxygen partial pressure (PO2) and lactate increase during exercise in patients with cardiovascular disease. BACKGROUND: Considerable controversy surrounds the relation between the increase in lactate during exercise and the oxygen supply to the exercising muscles. We assumed that femoral vein PO2 would be a measure of end-capillary PO2 during leg-cycling exercise and that it would decrease to a "floor" level when the critical capillary PO2 (the PO2 below which the capillary-mitochondrial difference would be too low to allow oxygen consumption) was reached. At the critical capillary PO2, anaerobic metabolism should take place, and lactate should increase in the effluent blood. METHODS: Ten patients with cardiovascular disease performed two 6-min constant work rate tests (moderate and heavy intensity) and an incremental exercise test to the symptom-limited maximum on a cycle ergometer. Femoral vein blood was repeatedly sampled through a percutaneous catheter before and during each exercise test. RESULTS: The PO2 rapidly decreased toward a minimal value with increasing oxygen uptake for all three tests in all patients. After reaching its nadir (18.2 +/- 2.0 mm Hg), the PO2 remained unchanged in five patients but increased in the other five patients despite the further increase in work rate and oxygen uptake. The relation between PO2 and oxygen uptake was characteristic for each patient and independent of the protocol used for the study. Femoral vein lactate did not change appreciably until PO2 reached the minimal (critical) value. Thereafter, it dramatically increased without a further decrease in PO2. The minimal PO2 was positively correlated with the peak oxygen uptake (r = 0.70, p = 0.01). CONCLUSIONS: During leg-cycling exercise, muscle capillary PO2 reaches a minimal value in the midrange of the subjects' work capacity before lactate concentration increases in patients with cardiovascular disease. The lack of further decrease in PO2 at the oxygen uptake at which lactate starts to increase suggests that the minimal capillary PO2 is the "critical" capillary PO2.

Aged↗
PubMed1994

Oxygen uptake kinetics are determined by cardiac function at onset of exercise rather than peak exercise in patients with prior myocardial infarction.

BACKGROUND: Resting cardiac function does not necessarily affect exercise capacity. However, to determine whether it affects early dynamics of oxygen uptake (VO2) during exercise, we measured VO2 during a constant work rate and during incremental exercise testing in patients with a history of myocardial infarction. VO2 kinetics and exercise capacity were compared between patients with relatively high left ventricular ejection fractions (LVEF > or = 35%, group 1) and those with lower ejection fractions (LVEF < 35%, group 2). METHODS AND RESULTS: Forty patients with a history of prior myocardial infarction (age, 57 +/- 10 years) were monitored during 6 minutes of moderate constant work rate testing (40 +/- 8 W) and during symptom-limited incremental exercise testing with a cycle ergometer. VO2 was calculated from respired gas analysis on a breath-by-breath basis. Cardiac output determinations were made with a computerized cadmium telluride detector every 10 seconds during exercise. The VO2 time constant during constant work rate exercise was slower in group 2 (58.0 +/- 7.6 seconds) compared with group 1 (45.8 +/- 10.5 seconds, P = .0002), indicating slower kinetics in group 2. The time constant for the rise in cardiac output during exercise was also slower in patients with lower EFs (63.0 +/- 12.8 versus 50.0 +/- 12.2 seconds). However, there were no differences in exercise capacity parameters, such as the VO2 or cardiac output at peak exercise, obtained during incremental exercise testing among the two groups. CONCLUSIONS: The prolonged time constant of VO2, which is primarily determined during early parts of exercise, reflects delayed cardiac output response in patients with severely impaired LV function. The time constant of VO2 during submaximal constant work rate exercise can be used as a sensitive and discriminant measure of impaired cardiac reserve in these patients.

Adult↗
PubMed1994

Mechanism of periodic breathing in patients with cardiovascular disease.

Although periodic breathing consisting of alternating hyperpnea and hypopnea has been recognized in heart failure patients, its mechanism has not been clarified. We hypothesized that heart failure patients who have oscillations in ventilation will also be found to have oscillations in pulmonary blood flow, as reflected in left ventricular ejection fraction. To test this hypothesis, we analyzed continuously gas exchange and left ventricular ejection fraction during exercise in cardiac patients who exhibited periodic breathing. Out of 48 consecutive patients with reduced left ventricular function who performed a symptom-limited incremental exercise test using an upright cycle ergometer, we selected 5 patients who exhibited clear ventilatory oscillations during exercise. These patients repeated the same exercise test on another day for measuring gas exchange and left ventricular ejection fraction continuously. Oscillatory changes were noted both in left ventricular ejection fraction and in ventilation in these patients. These observations offer support for the hypothesis that fluctuations in pulmonary blood flow are primarily responsible for the periodic breathing seen in heart failure patients.

Aged↗