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Biomedical subjects

K Kuramoto

Publications and source records attributed to K Kuramoto.

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

[Postprandial hypotension in the elderly with and without hypertension].

To clarify the mechanism of postprandial hypotension in the elderly, blood pressure and humoral factors were measured before and after meal, water, and glucose ingestion in 20 healthy elderly. The elderly patients were divided into 10 normotensive and 10 hypertensive cases. A reduction in systolic BP after meals in the hypertensive group was significantly larger than that in the normotensive group (-12.0 +/- 4.1 vs. 4.0 +/- 3.2 mmHg, p < 0.05). Systolic BP in hypertensive group significantly decreased at 30, 45 and 60 minutes after meals compared to the value before meals. However, no significant reduction in systolic BP was observed in the normotensive group. A change in systolic BP after meal significantly correlated with that after glucose, but not with that after water ingestion, suggesting that glucose intake mainly contributes to the postprandial hypotension in the elderly. An increase in plasma renin activity and plasma catecholamine were observed after meals in the normotensive group, but not in the hypertensive group. An increase in systolic BP significantly correlated with an increase in PRA. It was suggested that an impairment of the sympathetic nervous system in the elderly with hypertension was involved in the mechanism of postprandial hypotension.

Aged↗
PubMed1992

[A study on 24-hour ambulatory blood pressure in normotensive elderly, living in a local home for the aged].

Ambulatory blood pressure (BP) was non-invasively monitored in 124 normotensive elderly, living in an old people's home at the annual health examination. Cases were divided into 41 cases < 75 years (group A, mean age 70.6) and 83 cases > or = 75 years (group B, 82.7) for analysis of the office BP and 24-hour BP. Whole-day systolic BP in group B was significantly higher than those in the group A (p < 0.02) although no significant differences were observed in diastolic BP and pulse rate. Separated analysis of whole-day BP into daytime and nighttime revealed that the nighttime systolic BP in the group B was significantly higher than those in group A (132.2 +/- 17.4% vs. 123.8 +/- 18.6 mmHg, p < 0.02) whereas no significant difference was observed in day-time systolic BP between two groups (136.6 +/- 14.9 vs. 132.1 +/- 14.4 mmHg, n.s.). The day-night difference in systolic BP tended to be less in group B than in group A (4.5 +/- 11.6 vs. 8.2 +/- 12.2 mmHg, p < 0.10). The prevalence of non-dippers, who had a higher nighttime systolic BP than daytime systolic BP were 24.4% of the group A and 30.1% of the group B. It was concluded that systolic BP during the nighttime increased with the ageing process after age 60, although that during daytime did not change.

Aged↗
PubMed1992

[Changes in blood pressure and pulse rate during visit to a doctor's office].

Changes in blood pressure (BP) and pulse rate were measured during visits to a doctor's office by means of an non-invasive ambulatory BP monitoring device in 47 elderly hypertensive patients (mean age 73.0 years). Systolic BP increased from 140.5/85.4 mmHg to 157.9/85.7 mmHg immediately after entering the doctor's office and tended to return to the previous level at 5 minutes after entering although diastolic BP did not change during the visit. Pulse rate also increased slightly, but significantly on entering the office. The difference in BP between 25 minute before and just after entering an office was +17.4 mmHg in systolic. -0.1 mmHg in diastolic. If an increment in systolic BP more than 10 mmHg was defined as positive for white coat effect, they were observed in 59.6%. The frequency of white coat hypertension was 46.7% in the age of sixties, 65.2% in seventies and 66.7% in eighties but there was no significant difference among 3 groups. There was a tendency for white coat hypertensions to be more frequent in men compared than in women (p = 0.07).

Aged↗
PubMed1992

[Gianturco expandable metallic stents in the treatment of superior vena cava syndrome caused by lung cancer].

Treatment of superior vena cava syndrome (SVCS) caused by advanced lung cancer is still controversial. We inserted Gianturco expandable metallic stents (GEMS) in 5 patients with SVCS due to the extension of lung cancer. GEMSs were introduced intravenously through the catheter after intraluminal balloon dilation of the stenotic sites. SVCS was successfully and easily relieved by this method without any significant complication. GEMS placement seems to be a useful alternative to bypass grafting procedure for the treatment of SVCS.

Adult↗
PubMed1992

[Evaluation of postoperative pulmonary complications and remaining pulmonary arterial flow of lobectomized lung cancer patients using pulmonary digital subtraction angiography].

Postoperative pulmonary complications cause the decrease of the flow of remaining pulmonary circulation. We examined the effects of the difference of resected lobes on the postoperative course and remaining pulmonary circulation of the lobectomized lung cancer patients using a pulmonary digital subtraction angiography. In all cases with preoperative pulmonary complications, circulatory flow of the remaining lung on the operated side significantly decreased. In the cases without preoperative pulmonary complications, only the cases performed left upper lobectomy developed the decrease of the circulatory flow on the operated side. This seemed to be chiefly caused by a postoperative continual atelectasis of the remaining lower lobe due to kinking of the bronchus. On the other hand, the postoperative decrease of the residual pulmonary circulatory flow on the operated side was not developed in the cases undergoing a segmentectomy, even with pulmonary complications. Therefore, for any case requiring a left upper lobectomy or the case with an impaired lung requiring any type of lobectomy, contralateral pulmonary function should be exactly evaluated preoperatively.

Aged↗
PubMed1991

Effect of nifedipine tablets on ambulatory blood pressure in patients aged less than 60 and greater than 65 years with systemic hypertension.

To evaluate the effect of age on the pattern of circadian blood pressure after nifedipine tablets, ambulatory blood pressure after administration of low and high doses of nifedipine, taken twice daily, was measured over a 24-hour period in 10 elderly and 8 young hypertensive patients. After a 2-week control period without antihypertensive drug, 10 mg of nifedipine was administered twice daily for 2 weeks (low-dose period), followed by 2 weeks of 20 mg (high-dose period). At the end of each period, ambulatory BP monitoring was conducted every 30 minutes for 24 hours, using an ABPM 630 (Nippon-Colin, Komaki, Japan). In both groups, averages of systolic and diastolic BP for the entire day decreased significantly from the control to the low-dose periods. However, after the high-dose period, only the elderly group had further significant reduction of systolic BP, whereas no further reduction was seen in the young group. Separate analysis of whole-day data into daytime and nighttime values revealed that a further decrease in systolic BP after the high-dose period in the elderly group was a reflection of nighttime decline. It was suggested that circadian BP patterns after administration of nifedipine tablets in the elderly differed from those in young hypertensive patients, especially after administration of the high-dose.

Aged↗
PubMed1991

Receptor types mediating the rise in the cytosolic free calcium concentration by L-aspartate and L-glutamate in immature cerebellar neurons with N-methyl-D-aspartate receptors.

L-Aspartate (Asp) and L-glutamate (Glu) increased the cytosolic free calcium concentration ([Ca]in) in medium-sized cerebellar neurons having N-methyl-D-aspartate (NMDA) receptors. The sustained rise in [Ca]in induced by Asp, but not by Glu, was reduced by the addition of NMDA antagonists, which consistently suppressed the rise in [Ca]in induced by a low concentration of Asp or Glu in combination with glycine. The results suggest that Asp is a more preferential agonist of NMDA receptors than Glu, although Glu can also be an agonist in the presence of glycine.

2-Amino-5-phosphonovalerate↗
PubMed1991

GABA inhibits the rise in cytosolic free calcium concentration in depolarized immature cerebellar Purkinje cells.

gamma-Aminobutyric acid (GABA) reduced the peak rise or slowed the rate of rise in cytosolic free calcium concentration ([Ca]in) induced by quisqualate, kainate, or high KCl in immature cerebellar Purkinje cell bodies. The sustained rise or repeated transient of [Ca]in induced by tetraethylammonium, veratridine, or Bay-K-8644 was lowered to the basal level by adding GABA, although the inhibition by GABA of Bay-K-8644-induced rise in [Ca]in was only slight and transient in some cells. These findings indicate that GABA inhibits the rise in [Ca]in by hyperpolarizing the membrane potentials at Purkinje cell bodies.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed1991

Prevalence of antibody to hepatitis C virus in a blood donor population.

Blood samples from 2000 accepted blood donors and 343 deferred donors with antibody to hepatitis B core antigen (anti-HBc) and/or an alanine aminotransferase (ALT) elevation were evaluated for antibody to hepatitis C virus (anti-HCV). Sixteen (0.8%) of the 2000 sera initially reacted on enzyme-linked immunosorbent assay (ELISA); 12 (0.6%) were repeatably reactive. One repeatably reactive sample had an elevated ALT; two reacted on anti-HBc testing and had ALT elevations. When the repeatably reactive ELISA samples were tested by an immunoblot assay, four reacted, three were indeterminate, and five did not react. Among the 343 deferred donors, HCV antibodies were detected in 8 (3.8%) of 210 anti-HBc-reactive samples, 12 (11.8%) of 104 elevated-ALT samples, and 15 (52%) of 29 combined elevated-ALT and anti-HBc-reactive samples; 25 of 28 reacted on immunoblot. The anti-HBc-reactive sera were subdivided into groups according to strength of anti-HBc reactivity (weak or strong) and antibody to hepatitis B surface antigen status and then were compared for anti-HCV reactivity rates. The group of samples showing the greatest frequency of anti-HCV had strong anti-HBc reactivity. For blood donors, the anti-HCV test correlates with the surrogate tests for non-A, non-B hepatitis (anti-HBc and ALT); however, most anti-HCV-reactive units remain undetected by surrogate tests, so that implementation of anti-HCV screening should further reduce the transmission of HCV via transfusion.

Alanine Transaminase↗
PubMed1991

Analysis of advancing age on the response to nicardipine among 467 adult hypertensive patients.

The antihypertensive response to nicardipine was analyzed in 467 hypertensive patients who had participated in four similarly designed double-blind clinical studies in which the effectiveness of nicardipine was evaluated. This population was divided into five age groups. The difference in response rates between the youngest (less than or equal to 39 years) and oldest group (greater than or equal to 70 years) of patients was less than 5%. After 12 weeks of treatment with nicardipine, the rate of response for each decade ranged from 65% to 77%. The per cent decrease in blood pressure was not age dependent, but did correlate with the pretreatment systolic and diastolic blood pressure (P less than 0.001). No age-related trend in side effects was observed. The incidence of side effects ranged between 0% among the oldest patients to 17.3% in patients 50-59 years of age. No adverse metabolic effects were found in any age groups. These results indicate that nicardipine, a calcium entry-blocker, is effective and useful in adult hypertensive patients of all ages.

Aging↗
PubMed1991

Cardiac performance in elderly hypertensive patients with left ventricular hypertrophy: responses to isometric exercise and beta-agonists.

To assess the cardiac functional reserve of elderly hypertensive patients with left ventricular hypertrophy (LVH) we studied cardiac function after isometric exercise and beta-adrenergic stimulation. Forty-five elderly hypertensive and 16 normotensive patients (NC group) were recruited for the study. The hypertensive patients were divided into two groups: those with LVH (n = 17) mass index (LV mass index greater than 130 g/m2; H1 group) and those without LVH (n = 28) (H2 group). Echocardiographic studies were performed before and after isometric exercise (handgrip) and isoproterenol (ISP) administration. We measured the LV mass index, fractional shortening (FS), isovolumic relaxation time (IRT), and the ratio of late and early diastolic transmitral flow velocity (A/E). The FS at rest in the H1 group was significantly higher than those in the H2 and NC groups. In the H1 group, the IRT was elongated and A/E was greater than in the NC group, which indicated the impaired diastolic function in the H1 group. After the HG stress, the FS in the H1 group significantly decreased whereas it did not change in the H2 or NC groups. The FS increased in all three groups after the infusion of ISP, although the increment of FS was smaller in the H1 group. In conclusion, (a) diastolic function was impaired whereas systolic function was supranormal at rest in the hypertrophied heart of the elderly hypertensive patients and (b) when exercise or pharmacological stress was loaded, the systolic function deteriorated, suggesting the impairment of cardiac reserve in those patients.

Aged↗
PubMed1991

Does the variability of casual blood pressure contribute to progressive subcortical vascular encephalopathy of Binswanger's type?

Our hypothesis was that progressive subcortical vascular encephalopathy of Binswanger's type (PSVE) in the elderly can be induced by repeated hypotension or greater variability of blood pressure in hypertensives, regardless of antihypertensive therapy. We retrospectively studied PSVE blood pressure, and compared them with those in atherothrombotic cerebral infarction (ACI) or in hypertensive cerebral hemorrhage (HCH). During the last seven years prior to death, neither the annual variability nor the annual mean value of systolic or mean arterial blood pressures in PSVE was different from that in ACI or in HCH. The present study did not support our hypothesis.

Aged↗
PubMed1991

Effects of aging on the cardiopulmonary receptor reflex in hypertensive patients.

In order to evaluate the effects of aging on cardiopulmonary receptor function in hypertensive patients, hemodynamic responses after unloading were studied in middle aged and older hypertensive patients. Twenty-one hypertensive patients were divided into 2 groups according to age. The younger group consisted of 9 patients less than 65 years old (mean age: 57.2 years) and the older group contained 12 patients more than 65 years old (77.2 years). Following 10 min rest, deactivation of cardiopulmonary receptors was obtained by reducing central venous pressure through the application of graded negative pressures of -10, -20, and -40 mmHg to the lower body. Blood pressure, pulse rate, and forearm blood flow were measured at baseline and at each level of negative pressure. Furthermore, plasma norepinephrine and plasma renin activity levels were measured at baseline and at -40 mmHg. Forearm blood flow was measured by venous occlusive plethysmography using a Silastic strain gauge applied around the forearm. Forearm peripheral vascular resistance was calculated by dividing the mean arterial pressure by the forearm blood flow. Baseline mean blood pressure, pulse rate, and peripheral vascular resistance were similar in both age groups. Following lower body negative pressure (LBNP), mean blood pressure and pulse rate did not change, suggesting the selective deactivation of cardiopulmonary receptors. The increase in peripheral vascular resistance at LBNP of -40 mmHg in the older group (20.0 +/- 6.2) was significantly lower than that in the younger group (15.5 +/- 8.9, p less than 0.05). Furthermore, the increase in peripheral vascular resistance after LBNP was inversely related to age (Y = -0.32X + 38.8, r = -0.43, p less than 0.05). Increases in plasma norepinephrine and plasma renin activity in the older group were not different from those in the younger group. It is concluded that the sensitivity of cardiopulmonary baroreceptor function in hypertensive patients deteriorates with increasing age.

Aged↗
PubMed1991

[Cholesterol, atherosclerosis and cerebro-cardiovascular complications in 3,236 elderly autopsy cases].

The effect of serum cholesterol on aortic, cerebral, coronary and femoral atherosclerosis as well as on the incidence of cerebral and myocardial infarctions were analyzed in 3,236 consecutive autopsies in the elderly. Serum cholesterol levels declined over the age of 80 in both genders. The cholesterol levels of females were significantly higher than that of males in each age group from the sixties through the nineties. The increase in serum cholesterol was correlated with the progression of coronary atherosclerosis in both genders, but not with cerebral or femoral atherosclerosis. Slight progression of aortic atherosclerosis was observed when serum cholesterol was over 160 mg/dl. Cholesterol induced progression of coronary atherosclerosis was found in cases with hypertension, but not in the normotensive group. In accordance with the progression of coronary atherosclerosis, the incidence of myocardial infarction increased with an elevation of serum cholesterol levels, and this relationship between myocardial infarction and cholesterol levels was found only in patients with hypertension. No correlation was found between the incidence of cerebral infarction and serum cholesterol levels. It was concluded that hypercholesterolemia in the elderly is a risk factor of myocardial infarction in cases with hypertension, but is not a risk factor of cerebral infarction.

Aged↗
PubMed1991

[Myocardial infarction beginning with cerebral symptoms in 30 cases of cardio-cerebral apoplexy].

A clinicopathological analysis of myocardial infarction with an onset of stroke-like symptoms was carried out on 30 autopsy cases at the Tokyo Metropolitan Geriatric Hospital. The cases were classified into four groups according to the types of brain lesions, I: embolism (n = 17), II: thrombosis (n = 9), III: bleeding (n = 2), and IV: no remarkable focal lesion (n = 2). Classification was made based on clinical findings, and pathological features. The characteristic clinical findings were conciousness disturbance, no elevation of blood pressure at the onset of stroke, hemiplegia and shock. However, the typical anginal chest pain was found in only 17% of cases. The underlying diseases and complications were hypertension, atrial fibrillation (Af), disseminated intravascular coagulation (DIC), renal failure, malignant neoplasma, and diabetes mellitus. The incidences of Af, DIC, mural thrombus, non-bacterial thrombotic endocarditis (NBTE) were significantly higher in the group with cerebral embolism than in the group with cerebral thrombosis. The coronary stenotic index was also smaller in the group with cerebral embolism. Therefore, the major etiology of cardio-cerebral apoplexy was a simultaneous embolism to the brain and heart due to Af, NBTE or, DIC.

Aged↗
PubMed1991

[Systolic anterior motion of the anterior mitral leaflet and/or the chordae tendinae in the elderly].

Systolic anterior motion of the anterior mitral leaflet and asymmetric septal hypertrophy (ASH) are characteristic features of hypertrophic obstructive cardiomyopathy (HOCM) on an echocardiogram. Among 9,670 patients over 60 years old examined by echocardiography from January, 1984 to October, 1990, 55 patients showed systolic anterior motion of the anterior mitral leaflet and/or the chordae tendinae (SAM). We investigated clinical features and morphological features of the left ventricle on an echocardiogram in the 55 patients with SAM. They were classified into three groups according to the degree of SAM. Thirty eight cases (group I) had no mitral and/or chordal-septal contact, 10 (group II) had brief contact (less than 30% on the echocardiographic systole) and 7 (group III) had prolonged contact (greater than or equal to 30%). Ages ranged from 60 to 99 with a mean age of 78.2 years. There were 19 males and 36 females and there was a predominance of females in each group. Thirty five cases had hypertension and 34 left ventricular hypertrophy on electrocardiograms. One case of group I, 3 of group II and 7 of group III had a clinical diagnosis of HOCM. In comparison with each group, the incidence of LVH (SV1 + RV5 greater than or equal to 35 mm) was 52% in group I, 90% in group II and 83% in group III and that of LVH (SV1 + RV5 greater than or equal to 70 mm) was 29%, 20% and 67%, respectively. On echocardiographic examination, the diastolic descent rate of the anterior mitral leaflet in the 3 groups was 36.1 +/- 13.1 mm/sec, 19.4 +/- 13.1 mm/sec and 10.7 +/- 11.8 mm/sec (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1990

Subtypes and proportions of cerebrovascular disease in an autopsy series in a Japanese geriatric hospital.

Of 1721 consecutive autopsies performed on patients over 60 years of age in Tokyo Metropolitan Geriatric Hospital, 550 (32% of all autopsied cases) revealed symptomatic cerebrovascular lesions. Among the 550 patients, intracranial hemorrhage was found in 19%, cerebral infarction in 75%, and coexisting cerebral hemorrhage and cerebral infarction in 6%. Twenty-eight percent of the cerebral infarctions were embolic infarctions of cardiac origin, half of which were caused by nonvalvular atrial fibrillation, and 69% were non-embolic infarctions of cardiac origin. Progressive subcortical vascular encephalopathy accounted for 15% of the cerebral infarctions. Two-thirds of all lobar cerebral hemorrhages were amyloid angiopathy-related. Nonvalvular atrial fibrillation is the most important cardiac source of embolic stroke. Progressive subcortical vascular encephalopathy is one of the characteristic features of ischemic lesions, and cerebral amyloid angiopathy is an important cause of lobar cerebral hemorrhage in the aged.

Age Factors↗