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Biomedical subjects

K Maehara

Publications and source records attributed to K Maehara.

At least 91 records · Page 5Linked to original sources
PubMed1993

[Effects of nipradilol on the patients of angina pectoris: results from the study of the exercise electrocardiography using HR-ST loop method].

This study was performed to confirm the usefulness of 12 mg nipradilol, a beta-blocker with a vasodilator action similar to that of nitrate-type drugs, in the treatment of effort angina pectoris. It also discusses the mechanism of the action of this drug when using the exercise test heart rate-ST displacement analysis. The symptom threshold multistage graded exercise test was performed using nine patients with chronic stabilized effort angina pectoris after an observation period and an 8-week administration period and HR-ST analysis was performed simultaneously. The number of anginal attacks significantly decreased from the 2nd week, and the heart rate at rest decreased significantly in the prone position although blood pressure did not change. The maximum oxygen intake increased markedly from 13.7 +/- 1.1 ml/kg/min to 19.3 +/- 2.5 ml/kg/min, and the maximum ST decrease improved significantly from 1.72 +/- 0.45 mm to 1.17 +/- 0.19mm. In HR-ST analysis, delta ST/delta HR and delta ST/delta DP tended to improve slightly. Since monotherapy with a beta-blocker causes significant increase in delta ST/delta HR and delta ST/delta DP, it was assumed that a vasodilator action in addition to a beta-blocker action is involved in the improvement of maximum ST decrease brought about by nipradilol.

Adrenergic beta-Antagonists↗
PubMed1992

Effects of exercise stress on left ventricular end diastolic pressure-length strain relations in dogs with and without coronary stenosis.

OBJECTIVE: The aim was to elucidate the alterations of left ventricular diastolic properties, taking into account changes in unstressed length during exercise stimuli with and without coronary stenosis. METHODS: Left ventricular end diastolic pressure-length strain relations using segment length normalised to Lagrangian strain, and the rate of relaxation, were studied in seven open chest anaesthetised dogs with and without coronary stenosis on both left anterior descending and circumflex coronary arteries (approximately 30% resting flow reduction) during simulated dynamic exercise. Regional segment length was measured with ultrasonic crystals placed in the left anterior descending subendocardial region, and unstressed segment length at zero transmural pressure was obtained by occluding the vena cava. RESULTS: Peak negative dP/dt was decreased and isovolumetric left ventricular relaxation time constant increased by coronary stenoses; however neither changed significantly during simulated exercise. Left ventricular end diastolic pressure was significantly increased by coronary stenoses, from 3.1(SEM 0.8) to 7.0 (0.9) mm Hg (p < 0.05), and further increased to 15.5(1.1) mm Hg (p < 0.01) during simulated exercise, although right ventricular end diastolic pressure did not change. Unstressed length was increased in coronary stenoses from 9.03(0.08) to 9.89(0.13) mm (p < 0.01), and further increased to 10.34(0.14) mm (p < 0.01) during exercise, whereas it tended to decrease without coronary stenosis, from 9.03(0.08) to 8.79(0.11) mm during exercise. Left ventricular end diastolic pressure-length strain relations progressively shifted upward and leftward with coronary stenoses and subsequent exercise, but shifted downward and rightward during exercise without coronary stenosis. CONCLUSIONS: The increase in unstressed length or volume may contribute to exercise induced left ventricular dilatation observed in patients in effort angina. End diastolic distensibility decreases in both mild supply induced and exercise induced ischaemia, whereas in the normal heart, left ventricular end diastolic distensibility increases during exercise.

Animals↗
PubMed1992

[The effect of granulocyte elastase inhibitor (urinastatin) vaginal suppository on patients with imminent premature delivery].

Cervical maturation, dilatation and uterine contraction in imminent premature delivery are closely related to chemical mediators from activated granulocytes which infiltrate into the cervix. It is known that urinastatin (urinary trypsin inhibitor, UTI) inhibits many kinds of chemical mediators from granulocytes and macrophages such as granulocyte elastase (elastase) and interleukin 1. We examined the effect of a UTI suppository on uterine contraction and the elastase level in cervical mucus in cases of imminent premature delivery. We treated 43 cases of imminent premature delivery with tocolysis index 3 or 4 with 4 kinds of therapy: Group A (N = 12): ritodorine drop infusion therapy; Group B (N = 9): daily UTI suppository (1,000U) therapy; Group C (N = 14): daily UTI suppository + ritodorine drop infusion therapy; Group D: daily UTI suppository + ritodorine drop infusion + antibiotics (oral cepharosporine) therapy. The elastase level of cervical mucus before treatment was 0.76 +/- 0.40 micrograms/ml in group A, 0.93 +/- 0.43 micrograms/ml in group B, 0.85 +/- 0.40 micrograms/ml in group C and 0.90 +/- 0.41 micrograms/ml in group D. There was no significant difference between these groups. The elastase level in cervical mucus was 0.75 +/- 0.47 micrograms/ml in group A, 0.27 +/- 0.35 micrograms/ml in group B, 0.27 +/- 0.33 micrograms/ml in group C and 0.30 +/- 0.19 micrograms/ml in group D, respectively. The elastase level was decreased significantly in groups B, C and D. The time taken to depress uterine contraction was 65 +/- 66 min in group A, 375 +/- 336 min in group B, 70 +/- 64 min in group C and 58 +/- 53 min in group D, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Intravaginal↗
PubMed1992

[Loss of catecholaminergic neuron in the hypothalamus of multiple system atrophy].

Autonomic failure is one of the primary clinical features of multiple system atrophy (MSA); while the hypothalamus is thought to be a higher center regulating the autonomic nervous system. In the hypothalamus, catecholamine depletion had been confirmed by neurochemical studies but no marked changes had yet been demonstrated by pathological studies. Using three MSA and three control cases, we evaluated the quantitative changes of catecholamine (CA)-containing neurons in the hypothalamus. As markers of CA neurons, neuromelanin (NM)- and tyrosin hydroxylase (TH)-containing neurons were stained by Fontana-Masson and the immunohistochemical technique alternatively. Serial coronal sections, 10 microns thick, were evaluated every tenth section for NM neurons, while two sections were evaluated for TH neurons. The distributions of NM and TH neurons were almost identical; most of them were clustered in the periventricular and arcuate nuclei. The mean numbers of NM and TH neurons per slice were significantly lower in MSAs than in the controls (T test, p less than 0.01); the former were 21.0, 31.6, and 13.7 in MSAs and 78.4, 54.1, and 84.3 in the controls, while the latter were 1.5, 15.5, and 20.5 in MSAs and 48.0, 62.0, and 50.5 in the controls. The clinico-pathological correlation was suggested by the significant differences in the number of TH neurons between two MSA cases: a case with severe orthostatic hypotension and a case with a milder one. The ratio of TH and NM neurons, as obtained from the adjusted sections, was constant in all MSA cases, and there was a positive statistical correlation, but it altered in each control case.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1992

[Two cases of hemorrhagic shock and encephalopathy syndrome].

A 10-month-old male infant (case 1) and another male infant aged 1 year and 11 months (case 2) were admitted to our department because of fever, watery diarrhea and convulsion. On admission, they were unconscious and showed rigidity of the limbs. Laboratory examination revealed a marked increase in GOT and GPT, a decrease in platelet and antithrombin III and an increase in FDP. Metabolic acidosis was found by blood gas analysis. Brain CT showed an extensive area of low density in case 1, and low density centering on the cerebral basal ganglia and brainstem in case 2. Rotavirus was detected in case 2 by fecal examination. The clinical pictures in these cases closely resembled those of hemorrhagic shock and encephalopathy (HSE) reported by Levin et al. in 1983. The etiology of this disease is currently unknown, and its prognosis is poor. The relationship between this disease and rotavirus should be examined in future studies.

Brain Diseases↗
PubMed1991

[Membrane cholesterol and insulin receptor in erythrocytes].

The author studied influence of membrane cholesterol on insulin receptor behavior using human erythrocytes after modification of their membrane cholesterol contents. Insulin binding to the erythrocytes containing higher membrane cholesterol which were obtained from alcoholic liver cirrhosis (ALC) and familial lecithin: cholesterol acyl transferase (LCAT) deficiency patients was also examined. 1) Influence of modified membrane cholesterol contents on insulin binding to erythrocytes (in vitro experiments): The cholesterol content of human erythrocyte membranes was modified by incubating the cells with phosphatidylcholine/cholesterol and phosphatidylcholine vesicles. Then insulin binding to the erythrocytes was measured as a function of membrane cholesterol content. Low membrane cholesterol decreased insulin binding at 10 degrees C and 15 degrees C, but increased insulin binding at 25 degrees C and 37 degrees C. Scatchard plot analysis showed that low membrane cholesterol decreased a number of the receptor without alteration of affinity. Phosphatidylcholine spin probe showed a dual effect of cholesterol on membrane fluidity, fluidizing below but rigidifying membranes above 20 degrees C. It is suggested that membrane cholesterol affects insulin receptor behavior through alteration of membrane fluidity, depending on the phase state of the membranes. 2) Insulin binding and membrane lipid composition of erythrocytes from ALC and LCAT deficiency patients: The erythrocytes from both ALC and LCAT deficiency patients are known to have higher content of membrane cholesterol. Insulin binding and membrane lipid composition of erythrocytes in both diseases were measured to see the influence of cholesterol on insulin binding in sites. a) Erythrocytes from ALC patients: In the erythrocytes from ALC patients, cholesterol to phospholipid molar ratio was significantly increased as compared with normal subjects. In phospholipid acyl chains, contents of polyunsaturated fatty acid significantly decreased in ALC patients. Insulin binding to erythrocytes was significantly increased in the patients of ALC. Scatchard plot analysis (at 15 degrees C) showed significant increase of the receptor number in erythrocytes from the ALC patients as compared to the normal subjects, while the affinity did not differ between the groups. The increased cholesterol content in the erythrocyte membranes was suggested to be responsible for the increased receptor number and insulin binding to the erythrocytes from ALC patients. b) Erythrocytes from LCAT deficiency patients: Membrane cholesterol to phospholipid molar ratio was increased in two patients of LCAT deficiency studied. In phospholipid classes, increase of phosphatidylcholine and decreases of both phosphatidylethanolamine and sphingomyelin were observed in the erythrocytes from both patients.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1990

[A case of Becker muscular dystrophy with schizophrenic symptoms].

A 23-year-old male patient with Becker muscular dystrophy (BMD) who showed schizophrenic symptoms was reported. He tumbled easily and was poor at running since age at 8 years. He had difficulty in climbing stairs and was idle away all day long since age at 21 years. Although his premorbid personality was not schizoid, he showed auditory hallucinations and delusions without any psychogenetic moment at the age of 23. At first, he seemed to be schizophrenic, but after the treatment with antipsychotics, he always had an insight into his disease and exhibited natural emotional communication. He showed no autism and character changes. According to the Wechsler Adult Intelligence Scale (WAIS), intellectual impairment was notified (total IQ58). Neurological examinations revealed weakness and atrophy of muscles in the proximal part of his lower extremities, and pseudohypertrophy of calves. In the serum enzyme, serum creatine kinase (CK) level was elevated (700 U/L). Abnormal Q waves appeared in the leads, II, III, aVF, V5, V6 on the electrocardiogram (ECG), and the finding of the echocardiography suggested dilated cardiomyopathy. The electroencephalogram (EEG) revealed the basic rhythm of 9-10 Hz with 0 activities of 6-7 Hz which were predominant in frontparietal and central leads. The electromyogram (EMG) revealed a myopathic pattern with low voltage and short duration. A muscle biopsy from right biceps brachii disclosed the abnormal immunofluorescent staining pattern of dystrophin which is consistent with BMD patient, i.e., "patchy," discontinuous and faint immunoreaction at surface membrane of the fiber. Both molecular weight (380 kd: n = 400) and amount (30%; n = 100) of dystrophin were reduced.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Benign familial hematuria.

Fifty children had benign familial hematuria. They were from 43 families showing neither deafness, heavy proteinuria, nor chronic renal failure and had a nonprogressive course. Light microscopy of renal biopsy specimens showed little or no glomerular changes. Immunofluorescence showed no significant glomerular deposits of immunoglobulins or complement components, but deposition of C3 in the arteriolar walls was observed in 21 of the 39 patients examined. Electron microscopy demonstrated widespread attenuation of the glomerular basement membrane (GBM) in 19 patients, focal attenuation in 22, and normal GBM in nine. These observations suggest that patients with benign familial hematuria are heterogeneous and that the thin GBM may be related to hematuria.

Basement Membrane↗
PubMed1987

Mesangial changes in IgA nephropathy in children.

The mesangial changes in 92 renal biopsy specimens from 81 children with IgA nephropathy were correlated with the clinical and the other renal biopsy findings. Three types of mesangial changes were identified: mesangial hypercellularity was predominant compared with the increase in matrix in 34 biopsy specimens (type A), the degrees of mesangial hypercellularity and matrix increase were similar in 36 (type B) and matrix increase was predominant in 22 (type C). The interval between the onset of disease and biopsy was significantly shorter in biopsies with type A mesangial changes (P less than 0.01) and significantly longer in those with type C (P less than 0.01). Serial pathologic observations revealed that predominant mesangial hypercellularity was almost exclusively seen in the initial biopsy but predominant matrix increase was usually seen in the follow-up biopsy. The percentage of glomeruli showing sclerosis was significantly higher in biopsies with type C mesangial changes (P less than 0.05). At the latest follow-up, 58% of the patients showing type A and 57% showing type B lost their proteinuria, whereas only 9% showing type C lost their proteinuria (P less than 0.01). These findings suggest that predominant mesangial hypercellularity is characteristic of the early lesion of childhood IgA nephropathy, and progression of disease leads to gradual decrease of mesangial cellularity and increase of matrix with sclerosis.

Biopsy↗
PubMed1987

Macroscopic hematuria in childhood IgA nephropathy.

The clinical presentation, initial laboratory and renal biopsy findings, and subsequent clinical course in 205 children with IgA nephropathy were studied retrospectively. The findings in the 119 patients with macroscopic hematuria and those in the 86 without macroscopic hematuria were compared. There were no differences with regard to sex distribution, age at onset, initial renal function, incidence of hypertension, degree of proteinuria and degree of mesangial proliferation. At the latest follow-up, 3% of the patients with macroscopic hematuria and 8% without macroscopic hematuria had developed chronic renal failure; 8% of the patients with macroscopic hematuria and 20% without had heavy proteinuria with or without hypertension (p less than 0.01); 41% of the patients with macroscopic hematuria and 24% without macroscopic hematuria had normal urine, blood pressure and GFR (p less than 0.05). The disease appears to follow a significantly more benign course in children with macroscopic hematuria than in those without macroscopic hematuria. These observations suggest some macroscopic hematuria-related differences in the natural history of childhood IgA nephropathy.

Child↗
PubMed1986

A comparison of ST segment deviation and calculated solid angle during acute regional ischemia in the isolated canine heart at precordial, epicardial and intramyocardial lead surfaces.

Although solid angle analysis has been considered to be reasonable for explaining the distribution of ST segment deviation following ischemia, it has not been tested fully, especially for ST segment changes in various sites at different lead surfaces. Thus, we investigated the applicability of solid angle theory to the mechanism of ischemic ST segment deviation at intramyocardial, epicardial and precordial leads. We used seven isolated, coronary perfused, isovolumic contracting canine hearts in a homogeneous cylindrical volume conductor. ST segment potentials from 246 electrodes were continuously measured during left circumflex coronary artery occlusion for five minutes. The ischemic boundary was obtained from a postmortem angiography, and the solid angle subtended by the ischemic boundary was calculated at every electrode site. Despite the difference between epicardial and precordial ST segment potential distributions, there was a high correlation between measured ST segment potential and calculated solid angle at epicardial (r = 0.86 +/- 0.05, 0.77-0.93), precordial (r = 0.93 +/- 0.05, 0.84-0.99), and intramyocardial leads (r = 0.95 +/- 0.03, 0.91-0.99). We conclude that solid angle analysis can be used to approximate the distribution of ischemic ST segment deviation at different lead surfaces in acute ischemia.

Animals↗
PubMed1986

The influence of changes in the size of ischemic region on ST-segment potential distribution in isolated canine hearts.

In order to investigate how a change in the size of a ischemic region is reflected in ST-segment mapping studies, we produced two different sizes of ischemic regions by occluding proximal or distal portions of the left circumflex artery for five minutes, using ten isolated canine heart preparations. We examined the relationship between the geometry of the ischemic region and ST-segment potential distribution on the epicardial surface and that in the "precordium", in which the heart was suspended. The extent of the ischemic region was reflected differently on epicardial and "precordial" sites, in that the magnitude of epicardial ST-segment elevation decreased (p less than 0.001) while the "precordial" one increased (p less than 0.01). In the epicardium the degree of ST-segment elevation was almost uniform over the ischemic region, whereas in the "precordium" it was maximal at sites overlying the center of the ischemic region and progressively decreased approaching the periphery. However, frequent occurrence of intraventricular conduction disturbance was observed near the center of the ischemic region. As a result, the magnitude of epicardial ST-segment elevation near the center became larger than in the periphery. These results suggest that the classical solid angle theory provides a useful approximation of the ST-segment deflection in very acute ischemic phase, until development of the intraventricular conduction delay.

Animals↗