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Biomedical subjects

T Maeda

Publications and source records attributed to T Maeda.

At least 1,315 records · Page 73Linked to original sources
PubMed1983

Effect of ascorbate on the contractile response induced by DMPP in guinea-pig ileal longitudinal muscle strip.

The study concerned the effect of ascorbate on the contractile response induced by DMPP in the guinea-pig ileal longitudinal muscle. At 0.5-10 mM, sodium ascorbate shifted the dose-response curve for DMPP to the left and enhanced the maximum contraction. On the other hand, in the presence of ascorbate, the high potassium (40 mM)-induced contraction was not altered, and the contraction by acetylcholine and histamine in concentrations higher than 1 microM and 0.3 microM, respectively, was slightly reduced. Thus, ascorbate enhanced the contractile response caused by DMPP which induced acetylcholine release from nerve terminals indirectly by stimulating the ganglia of the Auerbach's plexus elements. This potentiating effect of ascorbate was studied with a dual organ bath which was partitioned into two compartments. When the oral half of the muscle strip was directly stimulated by DMPP applied to the oral compartment, a contraction of the unstimulated anal part was observed. This contraction was blocked by atropine or adenosine applied to the unstimulated part. Tetrodotoxin, applied to the stimulated part, abolished the contraction of the unstimulated part. The contraction of the unstimulated part was enhanced by ascorbate applied to the stimulated part but not to the unstimulated part. These results indicate that the contraction observed in the unstimulated part may have been caused by acetylcholine release from cholinergic nerves as a result of conduction of the oral part excitation by DMPP along cholinergic nerve fibers; ascorbate may have affected the ganglion cells in Auerbach's plexus to potentiate the action of DMPP.

Acetylcholine↗
PubMed1983

Comparative study of the glial fibrillary acidic protein in vertebrates by PAP immunohistochemistry.

Glial fibrillary acidic protein (GFA) has been visualized by direct peroxidase antiperoxidase (APA) immunohistochemistry in various vertebrates (cyclostomes, teleosts, amphibians, reptiles, birds, and several placental mammals). In this study GFA-immunoreactivity (GFA-I) was observed in all species examined except in cyclostomes and amphibians. Two types of immunoreactive elements were observed: astrocytes and long processes without visible somata. Astrocytic cells with GFA-I were first found in the snake, and more cells were in birds where the pattern of distribution was similar to that of mammals. Within mammals, few differences in the manner of localization were observed among different species, except in the corpus callosum and the ependymal and subependymal layers. Long straight processes were observed in the lower submammalians--the lamprey, carp, and turtle. They radiated through the neuropil from the ventricular wall and followed nerve fiber bundles in the white matter. An uncommon feature was observed in the turtle brain, which possessed very intense GFA-I within the ependymal layer. The presence of GFA-containing profiles in the ependyma of adult animals is discussed in relation to GFA-positive structures seen in the human brain during ontogeny or under certain pathological conditions.

Animals↗
PubMed1983

Flexural rigidity of singlet microtubules estimated from statistical analysis of their contour lengths and end-to-end distances.

Microtubules in solutions, observed under a dark-field microscope, show incessant Brownian movement such as translational, rotational and flexing motion. A large number of microtubules, spontaneously stuck to the under surface of a coverslip, were photographed and the contour lengths and end-to-end distances of their images were measured. From the statistical analysis of the contour lengths and end-to-end distances, a value for the parameter lambda representing the flexibility of singlet microtubules was estimated to be lambda = (6.8 +/- 0.8) . 10(-3) micrometers-1. From the value of lambda, the elastic modulus for bending, epsilon, and Young's modulus, Y, of singlet microtubules were computed to be epsilon = approximately 10(-16) and Y = approximately 10(9) dyne . cm-2, respectively. The microscopic elastic constant, k, of bonding between two tubulin monomers neighboring along the singlet microtubule was computed to be k = congruent to 10(2) dyne . cm-1. A singlet microtubule is an order of magnitude as strong against bending and as weak against stretching as an F-actin filament.

Animals↗
PubMed1983

Postzygotic D/D translocation homozygosity associated with recurrent abortions.

A Robertsonian translocation involving homologous D chromosomes was found in two cases with a history of recurrent abortions. In the first case the propositus was a 37-year-old phenotypically normal man who had a balanced t(14q14q) translocation. In the second case, a 27-year-old phenotypically normal woman was found to be a balanced t(15q15q) translocation carrier. The recurrent abortions in both cases were probably owing to this translocation.

Abortion, Habitual↗
PubMed1983

Subcostal 2-dimensional echocardiographic imaging of peripheral left coronary artery aneurysms in Kawasaki disease.

Our previous study provided a new 2-dimensional echocardiographic technique to detect peripheral right coronary artery aneurysms in Kawasaki disease, with use of the subcostal approach. An additional study was performed to detect peripheral left coronary artery aneurysms. Because the left anterior descending artery runs along the anterior interventricular sulcus and the left circumflex artery along the mitral valve ring, these regions were searched for coronary aneurysms by use of the subcostal imaging approach. Among 143 patients with Kawasaki disease, 44 left coronary aneurysms were visualized in 22 patients. Three aneurysms at the origin of the obtuse marginal artery and 1 in the further peripheral site of the left circumflex artery were observed in 3 patients. Two aneurysms at the origin of the second diagonal branch of the peripheral left anterior descending artery were detected. These echocardiographic studies were done prospectively, and their features coincided well in size, shape, and anatomic location with confirmatory angiographic appearances.

Aneurysm↗
PubMed1983

Dopaminergic cell differentiation in the developing chick retina.

The distribution and morphology of dopaminergic (DA) neurons in the chick retina was studied in the course of development. Fluorescent DA cells were first detected on the 13th day of incubation. They were always found in positions two or three cell rows externally from the junction between the inner plexiform layer (IPL) and inner nuclear layer (INL). On the 14th day, DA cells were found in the innermost row of the INL. Subsequently their processes extended not only bilaterally along the IPL-INL junction but also vertically into the IPL. As a result, three fiber layers were formed as laminae 1, 3 and 5 in the IPL. In the newly-hatched chick retina, a number of growth cone-like fluorescent structures with fine spikes were seen at the IPL-INL junction, indicating that DA fibers were still growing and elongating at least at hatching. On the 4th postnatal day, the ramification of dendritic processes was very prominent and they often showed a spiral configuration.

Animals↗
PubMed1983

Vocal fold polyps and nodules. A 10-year review of 1,156 patients.

We investigated the clinical records of 784 patients with vocal fold polyps and 372 patients with vocal fold nodules who were seen in our clinic during the 10 years from 1971 to 1980. Polyps were frequent in middle ages in both sexes whereas nodules were common in boys and middle-aged women. Vocal abuse was the most important etiologic factor. No regular voice therapy was available for lack of voice therapists. Surgical removal yielded the best result, but not in all the patients operated.

Adolescent↗
PubMed1983

Corticotropin-releasing factor test in normal subjects and patients with hypothalamic-pituitary-adrenal disorders.

Corticotropin-releasing factor (CRF) tests were performed in normal subjects and patients with hypothalamic-pituitary-adrenal disorders. In normal subjects, after iv administration of 500 micrograms synthetic ovine CRF, plasma ACTH rose significantly to approximately 3.6 times the basal level at 30-60 min and cortisol reached a peak of 2.3 times the basal level at 60-90 min, whereas aldosterone peaked at 1.6 times the basal level at 60 min. Injection of 100 micrograms CRF in normal subjects also caused a significant increase in plasma ACTH and cortisol levels but only a slight increase in aldosterone. However, the total hormone released and their peak levels were lower than those elicited by the 500-microgram dosage. In patients with Cushing's disease, although the basal and peak levels of plasma ACTH and cortisol induced by administration of CRF were variable, the ratios of increase for the two hormones elicited by CRF were lower than those in normal subjects, especially for cortisol. In patients with Cushing's syndrome due to an adrenal adenoma, basal levels of ACTH were markedly suppressed and plasma ACTH and cortisol did not rise after CRF. In patients with isolated ACTH deficiency or Sheehan's syndrome the basal level of plasma ACTH was less than 5 pg/ml and no change in plasma ACTH occurred after injection of CRF. In patients with Nelson's syndrome or Addison's disease the basal levels of ACTH were extremely elevated but infusion of CRF increased plasma ACTH to even higher levels.

Addison Disease↗
PubMed1983

Effect of shakuyaku-kanzoh-toh, a prescription composed of shakuyaku (Paeoniae Radix) and kanzoh (Glycyrrhizae Radix) on guinea pig ileum.

The actions of shakuyaku-kanzoh-toh (SK), a prescription of the traditional Chinese medicine, on an isolated guinea pig ileum were studied by comparing those of shakuyaku (S) (peony root, Paeoniae Radix) and kanzoh (K) (licorice root, Glycyrrhizae Radix). SK, S and K suppressed the neurogenic contractions of ileum induced by electrical stimulation and ganglionic stimulating agents such as DMPP and nicotine. Although S did not influence acetylcholine (ACh)-induced contraction of ileum, K inhibited ACh-induced contraction to the same extent as the neurogenic contraction. Also SK inhibited ACh-induced contraction but its inhibition was smaller than the inhibition of the neurogenic contraction. SK and K inhibited 40 mM KCl-induced contraction of ileum and the specific binding of 3H-QNB on muscarinic receptors in ileum, but S at 3 X 10(-4) and 10(-3) g/ml, which were enough to suppress the neurogenic contraction of ileum, did not inhibit them. These results suggest that the inhibitory actions of S and K on the neurogenic contraction are due to an inhibition of ACh release from cholinergic nerve and an inhibition of ACh action on ileum smooth muscle, respectively, and that the inhibitory actions of SK are responsible for both inhibitions by S and K. The inhibitions of ACh action by SK and K are presumed to be due to inhibitions of ACh binding on muscarinic receptors and of contractile machinery of smooth muscle.

Acetylcholine↗
PubMed1983

Oxygen consumption rate as a measurement of freeze-induced damage to chicken spermatozoa.

The present study was conducted to determine if oxygen consumption rate of postthaw spermatozoa could be used as the indicator of freeze-induced damage. Pooled semen was diluted fourfold with 5.7% glucose solution containing various levels of glycerol or N-methylformamide for freezing by the pelleting method. Sperm motility and oxygen consumption rate were determined after thawing the samples at 37 C. 1) The maximum motility and oxygen consumption rate of postthaw spermatozoa were observed at 10 and 7% glycerol, respectively. However, no significant differences existed among semen samples diluted in 7, 10, and 15% glycerol. 2) The motility and oxygen consumption rate of spermatozoa frozen with 6 to 9% of N-methylformamide were higher than those of spermatozoa frozen with 0, 3, 12, or 15%. 3) A highly significant positive correlation was observed between motility and oxygen consumption rate immediately after thawing and also after 10 min incubation at 20 C with either cryoprotectant. 4) The polarographic measurement of oxygen consumption rate of postthaw spermatozoa appeared to be a reliable method for evaluating freeze-induced damage to chicken spermatozoa.

Animals↗
PubMed1983

Absorption, distribution and excretion of 3-(sulfamoyl[14C]methyl)-1,2-benziosoxazole (AD-810) in Rats, Dogs and Monkeys and of AD-810 in Men.

Disposition of 3 - (sulfamoyl[14C]methyl) - 1,2-benzisoxazole ( [14C]AD-810) in rats, dogs and monkeys after oral administration in 20 mg/kg was studied. In preliminary human studies, healthy subjects ingested 200 mg of AD-810. [14C]AD-810 was found to be completely absorbed from digestive tracts in animals, since urinary and biliary excretion accounted for virtually total recovery of dosed radioactivity. Plasma levels reached maxima at several hours after administration in all species examined and decreased exponentially. In rats, tissue levels were virtually similar to plasma levels indicating rather even distribution in the body, and tissue radioactivity disappeared with the similar rate to plasma. Autoradiographic findings on the distribution were consistent with radiometric results. Radioactivity was evenly distributed in fetus in the pregnant rat with the similar level to maternal tissue levels. Like other sulfonamide derivatives, AD-810 was markedly taken up by erythrocytes in all species. [14C]AD-810 radioactivity was mostly excreted within 48 to 72 h after administration and its major route was urine in animals. In men, excretion of unchanged AD-810 and its metabolite in urine was found to be rather slow. No significant differences were found in absorption, distribution and excretion of radioactivity after 7 consecutive daily oral dosings of [14C]AD-810 in rats.

Animals↗
PubMed1983

[Effect of diltiazem on diastolic performance of the hypertrophied left ventricle in patients with systemic hypertension and hypertrophic cardiomyopathy].

We studied the effect of a calcium antagonist, diltiazem, on left ventricular (LV) diastolic performance of hypertrophied hearts in five patients (pts) with systemic hypertension (HHD) and 6 pts with hypertrophic cardiomyopathy (HCM) by a combined phonoechocardiographic technique. Data were analyzed before and after the oral administration of diltiazem (90-180 mg/day). In HHD, the prolonged LV isovolumic relaxation time, measured from the onset of the aortic component of the second heart sound to the beginning of the mitral valve opening, decreased significantly from 112 +/- 17 to 90 +/- 9 msec (p less than 0.01) and normalized LV peak filling rate during rapid filling phase increased in all pts without a statistic significance. This filling rate during atrial contraction phase decreased (1.61 +/- 0.59 to 0.93 +/- 0.22 sec-1, p less than 0.05). In HCM, LV isovolumic relaxation time and normalized LV peak filling rate during rapid filling phase showed no significant change, although normalized LV peak filling rate during atrial contraction phase decreased significantly (1.20 +/- 0.27 to 1.05 +/- 0.24 sec-1, p less than 0.05). In both pts groups, no significant changes were observed in R-R interval, systolic blood pressure, LV end-systolic dimension, end-diastolic dimension and fractional shortening of the LV minor axis before and after the administration of diltiazem. These data indicate that diltiazem shortens abnormally prolonged LV diastolic relaxation time and improves LV diastolic filling in pts with HHD, whereas diltiazem failes to show such effects in pts with HCM except for a decrease in the normalized LV peak filling rate during atrial contraction phase.

Administration, Oral↗