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Biomedical subjects

A Koike

Publications and source records attributed to A Koike.

At least 91 records · Page 5Linked to original sources
PubMed1992

Is the anaerobic threshold truly anaerobic?

This study was done to address the question as to whether there was an exercise metabolic rate below which the O2 supply to the muscles was adequate to meet the O2 requirement and above which the O2 supply was inadequate, ie, an anaerobic threshold (AT). The question was addressed using 2 approaches: (1) The arterial lactate/pyruvate ratio was measured to see if it increased at an O2 uptake (VO2) threshold or continuously as a log function over the entire range of exercise work rates. (2) Anticipating that the VO2 would be affected by reducing O2 supply only for work rates above the AT, the effect of reducing O2 delivery on VO2 for work rates over the entire range of the subject's work capacity was determined. Lactate (L) and pyruvate (P) were measured in arterial blood in 10 normal subjects. The L/P ratio was found not to increase until a threshold work rate was reached, the VO2 being that identified as the AT. Above that VO2, the L/P ratio climbed steeply. Arterial L/P ratio measurements fit a threshold model considerably better than a continuous model, supporting the concept that exercise done at low and moderate work rates can be performed without a change in cell redox state; but redox state does change rapidly in relation to the work rate increase above the AT. In the second study, the cardiorespiratory responses to various levels of exercise were studied in 10 normal subjects before and after carboxyhemoglobin (COHb) was increased to 10% and 20%. The lactic acidosis threshold and VO2 kinetics were examined. Blood lactate concentration increased only above the AT. The AT was systematically decreased by the percent of COHb increase. Importantly, VO2 was reduced and VO2 kinetics were slowed in response to exercise only for the metabolic rates above the AT. These studies demonstrate that lactate increase in response to exercise is O2 flow sensitive, and there is a threshold work rate above which this sensitivity becomes manifest.

Acidosis, Lactic↗
PubMed1992

[A family of Marchesani syndrome with mitral valve prolapse and anuloaortic ectasia].

Marchesani syndrome consists of short statue, small spherical lens, glaucoma and brachydactyly, which are manifestations of hyperplastic connective tissue disease in systemic organs of mesodermal origin (Marchesani 1939). Among nearly 200 cases of Marchesani syndrome reported in the ophthalmology field, none has shown cardiac manifestations which typically characterize Marfan syndrome caused by hypoplastic connective tissue disorders. We experienced 2 cases which met the diagnosis of Marchesani syndrome and yet showed annuloaortic ectasia and mitral valve prolapse. A 30-year-old man and a 26-year-old woman who are siblings suffered from manifested brachydactyly, spherophakia, glaucoma and cardiac involvements. Their parents are in consanguinity. These unprecedented cases with mixed manifestations provide the evidence of possible gene-crossing between these 2 dystrophic mesodermal disorders.

Adult↗
PubMed1992

[Extrapleural approach for patent ductus arteriosus and coarctation of the aorta].

During the period of 1989 to 1990, 6 consecutive children with patent ductus arteriosus or coarctation of the aorta underwent operative therapy. Ligation or division of patent ductus arteriosus or subclavian flap angioplasty for coarctation of the aorta were performed by extrapleural approach with axillary or posterolateral incision. Patients' ages ranged from 9 days to 8 years. Weights ranged from 3 to 30 kg. It was very easy to have better operative field and beneficial to protect the lung against mechanical injury. Extrapleural approach was not so easy in an 8-year-old patient with firm connective tissue. Therefore, this procedure is considered to be suitable for younger children.

Aortic Coarctation↗
PubMed1992

Effect of acute reduction in oxygen transport on parameters of aerobic function during exercise.

The binding of haemoglobin by carbon monoxide reversibly decreases the blood O2 carrying capacity, providing a useful model of impaired circulatory O2 transport. We evaluated noninvasive parameters of aerobic function during exercise to detect small changes in O2 transport, using carbon monoxide. Ten normal subjects performed both symptom-limited incremental and two levels of constant work rate on a cycle ergometer while breathing air and air with added carbon monoxide to cause carboxyhaemoglobin (COHb) to be approximately 11% (level of heavy cigarette smoker) and 20%. Maximal O2 uptake (VO2 max), the anaerobic threshold (AT) determined from the plot of CO2 output as a function VO2 (V-slope, the ratio of increase in VO2 to work rate increment (delta VO2/delta WR) and the upper slope of the V-slope analysis were measured while progressively increasing work rate. These changed in approximately the same percent as the increase in COHb. For the constant work rate tests, the time constant of VO2 and the difference in VO2 at six minutes as compared to three minutes of exercise (delta VO2 (6-3)) were significantly increased when COHb was increased. These noninvasive parameters of aerobic function, determined from the cardiopulmonary response to incremental and constant work rate exercise, particularly when used in combination, proved to be sufficiently sensitive to objectively detect small changes in O2 transport to the working muscles during exercise.

Adolescent↗
PubMed1992

[Carpentier's procedure for Ebstein's anomaly: successful and failed cases].

Two adult cases of Ebstein's anomaly underwent Carpentier's procedure. In the first case longitudinal plication limited to free wall of atrialized ventricle was performed and postoperative course was uneventful. In the second case preoperative echocardiography showed apparently restricted movement of anterior leaflet of the tricuspid valve which was compatible with intraoperative findings. That is, inferior edge of anterior leaflet was partly adherent to ventricular wall and systolic bulging of leaflet was significantly impaired which was left untouched but should be repaired by additional procedure. Six days after operation the tricuspid valve replacement was required for persistent right heart failure due to residual tricuspid regurgitation. In the same case longitudinal plication of atrialized ventricle reported by Carpentier and colleagues resulted in excessively small annulus. Therefore we had to reduce the plication and did not perform following atrial plication to avoid direct injury to conduction system or disturbing coronary venous return. In conclusion exact preoperative evaluation of anterior leaflet of the tricuspid valve especially subvalvular anatomy is essential to Carpentier's procedure, as Carpentier and colleagues emphasized, and conservative longitudinal plication of the atrialized ventricle limited to free wall is favorable when excessively small annulus might be concerned.

Cardiac Surgical Procedures↗
PubMed1991

Effects of enoximone on exercise tolerance in patients with mild to moderate heart failure.

To evaluate the efficacy of enoximone on exercise tolerance in patients with mild to moderate heart failure, 33 patients underwent cardiopulmonary exercise tests before and 3 hours after placebo or after receiving 25 or 100 mg of enoximone administered randomly in a double-blind manner. The electrocardiogram was monitored and blood pressure measured every minute throughout cycle ergometer exercise testing with a ramp protocol in which the work rate increased 1 W every 6 seconds after a 4-minute 20-W warm-up. Minute ventilation, oxygen uptake (VO2), and carbon dioxide output were measured every 10 seconds in order to determine anaerobic threshold (AT) and peak VO2. Five patients were excluded from evaluation before breaking the double-blind key because of insufficient data. Heart rate increased and systolic blood pressure decreased throughout the testing only in the group taking 100 mg (n = 10). Significant increases in AT (14.4 to 16.2 ml/min/kg) and peak VO2 (20.8 to 22.9 ml/min/kg) were observed in the group taking 100 mg. The increases in AT showed a dose response, namely +0.7% in the placebo (n = 9), +6.9% in the 25-mg (n = 9) and 12.5% in the 100-mg group. The work rates at the AT point increased in the 25- and 100-mg groups. These results indicate that a single oral administration of enoximone improves exercise tolerance in patients with mild to moderate heart failure.

Aged↗
PubMed1991

Malignant "triton" tumor in the thyroid--a case report.

This report presents a very rare case of a malignant "Triton" tumor developing in the thyroid. Although malignant "Triton" tumors have often been known to develop in cases of neurofibromatosis, Von Recklinghausen's disease, this patient showed no clinical evidence of that disease. Total thyroidectomy including left standard radical neck dissection was followed by postoperative irradiation to the neck. Despite this, local and distant metastases developed four months after treatment and the recurrent foci did not respond to chemotherapy or irradiation. The clinical course of this case mimicked that of anaplastic carcinoma of the thyroid and interestingly, a minimal lesion of papillary adenocarcinoma was found to exist concurrently in the thyroid gland of this patient.

Adenocarcinoma, Papillary↗
PubMed1991

The work-rate-dependent effect of carbon monoxide on ventilatory control during exercise.

The effect of low levels of carbon monoxide (CO) was studied during exercise in order to determine the work-rate dependent effect of CO breathing on exercise ventilation (VE). Ten normal subjects (aged 32.8 +/- 7.1 years) were studied during air breathing and air with added CO to bring carboxyhemoglobin (COHb) to approximately 11% and 20%. During the incremental exercise test, VE was not affected by CO breathing at work rates below the lactic acidosis threshold (LAT), defined as the O2 uptake above which CO2 is excreted by the lungs consequent to buffering of metabolic acid (not hyperventilation) (Beaver et al. (1986) J. Appl. Physiol. 60: 2020-2027). However, VE was increased above the LAT as work rate and COHb saturation were increased. At the end of constant work rate exercise, the increase in VE caused by increased COHb was positively correlated (r = 0.83, P less than 0.0001) with the increase in venous lactate sampled 2 min into recovery. This was complemented by a decrease in end-tidal PCO2 versus lactate (r = 0.76, P less than 0.0001). We conclude that the increase in exercise VE resulting from COHb levels up to 20%, is restricted to work rates above the LAT, and is proportionately higher, the greater the lactic acidosis.

Adolescent↗
PubMed1991

[Radical surgery with pubectomy for primary male posterior urethral cancer--a case report].

A 38-year-old male patient with the past history of polioencephalopathy was admitted with urinary retention and high grade fever. Although he was able to walk he had the intelligence of a 3-year-old child and his spine, thorax, fingers were deformed remarkably. Immediately after the admission, cystostomy was carried out and 600 ml of stinky and cloudy urine was noted. Although intensive antibiotic therapy was performed, high grade fever with leucocytosis (greater than 15,000/mm2) persisted for more than 10 days. Retrograde urethrogram showed stricture in the anterior urethra as well as irregular filling defect in the bulbomembranous urethra. After urethral dilation using urethral dilators, 18Fr nephrostomy balloon catheter was indwelled and the patient was discharged. However, the urethral irregular filling defect was unchanged and cytological examination of urine and urethral secretions revealed class V. After the readmission, endoscopic examination revealed papillary tumor lesions occupying the whole posterior urethra were found. With the diagnosis of invasive posterior urethral cancer, anterior exenteration by en bloc pubectomy, pelvic lymphadenectomy and ileal conduit urinary diversion were carried out. On the surgical specimen, the tumor occupied the bulbomembranous and prostatic urethra. Histopathological diagnosis was TCC G3 greater than SCC, stage B. Since the tumor invaded the serosa of the membranous urethra, we thought it could not be removed completely without the pubctomy.

Adult↗
PubMed1991

[A case of cardiac lipoma in the ventricular septum].

A 45-year-old man was admitted because of systolic murmur after routine medical checking. Echocardiography and cardiac catheterization revealed a large mass in the ventricular septum which bulged into right ventricular cavity with pressure gradient of 29 mmHg. The diagnosis of cardiac lipoma was made by CT scanning which showed the mass with attenuation values of -94 Hounsfield units. MR imaging demonstrated the mass with high signal intensity which corresponded to that of subcutaneous fatty tissue. The tumor was resected through the right ventricular incision with the use of cardiopulmonary bypass. It was yellow, elastic soft, sized 6.5 x 4.3 x 3.5 cm, and weighed 44.7 g. On histological examination, the tumor was composed of mature fatty tissues contained with myocardial fibers. After operation, he had split of the ventricular septum, which was closed primarily after removal of the lipoma, and left-to-right shunt. Patch reinforcement was performed at the right ventricular side of the septum on the postoperative 18th day. Postoperative electrocardiogram showed left axis deviation and complete right bundle branch block. This finding seems to be resulted from injury to the anterior branch of left bundle. The postoperative course was uneventful. This patient is the second case of removal of cardiac lipoma in the ventricular septum on review of the literature in Japan.

Heart Neoplasms↗
PubMed1991

[Intelligence and language of individuals who incurred left hemisphere injury at no later than 3 years of age].

It is generally considered that damage to the brain during infancy and young childhood results in milder or different syndromes than does brain injury incurred during adulthood. However, only several past studies employed CT scans to confirm that lesions are confined to one of the two cerebral hemispheres. We examined intelligence and language skills of 5 cases, which sustained nonprogressive damage exclusively to the left cerebral hemisphere before 1 year of age, and 1 case, which incurred nonprogressive left hemisphere injury at 3 years of age. These cases were tested at 9 to 25 years of age, or 8 to 22 years after inflicting injuries. The following scales and tests, all of which are Japanese versions, were employed: the Wechsler Intelligence Scale for Children-Revised (WISC-R) to measure intelligence of 3 cases at 15 years of age or younger, the Wechsler Adult Intelligence Scale (WAIS) for 3 cases older than 15 years of age, the Western Aphasia Bettery (WAB) to measure language skills, and the shortened version of the Token Test to assess auditory comprehension skills. Upon administration of the tests, we obtained the following results: 1) Although 1 case had a large lesion in the left hemisphere, she exhibited a high IQ of 111, and was adapted well as a college student. The result suggested that large lesions, if incurred at no later than 1 year of age, may affect intelligence to only a little or negligible extent. 2) Verbal IQ generally declines from left hemisphere damage in adults. In all of our subjects, however, verbal IQ was similar to performance IQ.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

[Analysis of factors influencing early patency of saphenous vein grafts].

To determine factors affecting early patency of saphenous vein grafts, 140 grafts in 65 patients were studied angiographically within 2 months after operation. Twenty of the 140 grafts were occluded. Sixteen variables were extracted from the angiographic findings, intraoperative measurements, clinical characteristics, and biochemical data. The univariate and multivariate analyses were performed to assess their predictive value. Of 16 variables, 3 (coronary artery internal diameter, graft flow, and coronary artery resistance) correlated significantly with graft patency in the univariate analysis. The multivariate analysis selected coronary artery resistance, coronary artery internal diameter, and degree of proximal stenosis as predictors of early graft patency. Of these 3 factors, the coronary artery resistance influenced graft patency mostly. Therefore, the coronary artery resistance was considered to be the most reliable predictor of early graft patency.

Adult↗
PubMed1991

[A case of completely unroofed coronary sinus with persistent left superior vena cava].

A 34-year-old female presented with exertional dyspnea. Investigation by echocardiography and cardiac catheterization showed completely unroofed coronary sinus with persistent left superior vena cava (PLSVC) (coronary sinus atrial septal defect, absence of the coronary sinus, and PLSVC-left atrium connection) combined with tricuspid valve regurgitation. Angiocardiography made by injection into the PLSVC demonstrated that the PLSVC was connected to the hemiazygos vein before it drained into the left atrium and the left innominate vein was absent. Although jugular vein pressure rose up to 18 mmHg when the PLSVC was temporarily occluded, it remained unchanged. Therefore, simple ligation of the PLSVC was selected for therapy. Patch closure of the atrial septal defect, tricuspid valve repair, and ligation of the PLSVC was performed successfully.

Adult↗
PubMed1990

Evidence supporting the existence of an exercise anaerobic threshold.

In this paper, we provided evidence to support the concept that work above the anaerobic threshold, measured by the V-slope method, is, in fact, performed partially anaerobically. In contrast, work performed below the anaerobic threshold is totally aerobic (Figure 2, 4 and 5). The VO2 at the transition from aerobic to partial anaerobic metabolism must depend on cardiovascular performance since it regulates the capillary PO2 level needed for O2 diffusion transport into the mitochondria (Figure 1). At high work rates, the capillary PO2 needed for the oxygen requirement might not be met by the cardiovascular oxygen supply. This would result in the oxygen consumed being less than the oxygen required by the working tissue (Figure 2), with the oxygen equivalent difference necessarily coming from anaerobic metabolism. The consequences are increased lactate formation and metabolic acidosis, and the physiological and biochemical disturbances which result from the latter.

Adolescent↗
PubMed1990

Beat-to-beat evaluation of cardiac function during recovery from upright bicycle exercise in patients with coronary artery disease.

The purpose of this study was to evaluate the time course of cardiac function during recovery from upright bicycle exercise in patients with coronary artery disease. Twelve patients with coronary artery disease performed a symptom-limited exercise test on a cycle ergometer. Left ventricular function was continuously monitored during exercise and recovery with a computerized cadmium telluride detector following the intravenous injection of technetium-labeled red blood cells. Although the end-diastolic volume (153.4 +/- 76.1 ml) and end-systolic volume (100.5 +/- 67.3 ml) at the end of exercise were significantly higher than the respective resting values, stroke volume (52.8 +/- 16.1 ml) and ejection fraction (38.0 +/- 12.2%) were not different from the respective resting values. The recovery of cardiac output was relatively slow compared with that of heart rate, because stroke volume rose sharply early in recovery. The rise in stroke volume was chiefly a result of a significant decrease in end-systolic volume between 1 and 4 minutes of recovery. These changes may result from an immediate afterload reduction coupled with a relatively slow decrease in sympathetic stimulation. The time course of cardiac function during recovery from exercise in cardiac patients is substantially different from that of normal subjects and may be a sensitive way to evaluate the peripheral vascular function and deteriorated cardiac function in cardiac patients.

Adult↗