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Biomedical subjects

H Ando

Publications and source records attributed to H Ando.

At least 379 records · Page 21Linked to original sources
PubMed1984

Studies on the off-response of the rod photoreceptors in the isolated frog retina.

Transretinal potential changes induced by a 30 sec exposure to 503 nm light were studied in the dark-adapted frog isolated retina. The retina was treated with aspartate and 0.5 mM Ba2+ to suppress the PII and slow PIII components of the electroretinogram, and therefore the response to the light stimulus consisted of the on-response (fast PIII response) and the off-response. The amplitude of the off-response was proportional to that of the on-response when the stimulus intensity was weak. The amplitude ratio of the off-response to the on-response was unaffected by partial bleachings of rhodopsin. In the presence of 700 nm background illumination, the amplitude of the on-response was decreased, whereas that of the off-response was increased. The amplitude of the off-response increased to about four-fold that of the original response at 3 hr after turning on the background illumination, but the effects of 480 nm background light were less remarkable. Both the on- and off-response, however, had a peak spectral sensitivity at about 500 nm, regardless of the presence of background light. From these findings, it was suggested that the red rods contribute to the development of the off-response, but the cones would also contribute through small focal gap junctions between the cones and the red rods.

Action Potentials↗
PubMed1984

Teratogenicity of thiabendazole in ICR mice.

Thiabendazole (TBZ) was tested for teratogenicity using Jcl:ICR mice. TBZ suspended in olive oil was given orally to pregnant mice at different stages of organogenesis. All foetuses were removed from the uterus on day 18 of gestation, and were examined for external and skeletal anomalies. In mice given 700, 1300 or 2400 mg TBZ/kg body weight/day on days 7-15 of gestation, dose-dependent external and skeletal anomalies, especially cleft palate and fusion of vertebrae, were observed. In mice given a single dose of TBZ (2400 mg/kg) on any one of days 6-13, an increased number of malformations was observed. Various types of malformation occurred, especially in the mice treated on day 9. Reduction deformity of limbs was found in mice given TBZ on days 9-12, a change that has not previously been observed to occur spontaneously in normal ICR mice in our laboratory. In order to determine a dose-response relationship, groups of mice were given one of 17 doses of TBZ (30-2400 mg/kg) on day 9 of gestation. The number of litters having foetuses with reduction deformity of limbs and of those having foetuses with skeletal fusion increased in proportion to the dose of TBZ. The regression lines of Y (probit response) on X (log dose) for reduction deformity of limbs and for skeletal fusion were Y = 2.47X - 3.65 and Y = 1.54X + 0.48, respectively. The effective doses (ED1) for the two malformations were 362.0 and 26.4 mg/kg, respectively.

Animals↗
PubMed1984

Congenital dilatation of the common bile duct in children.--The etiologic significance of the narrow segment distal to the dilated common bile duct.

Radiographic studies of 26 choledochal cyst patients were evaluated. Abnormal junction of the pancreatico-biliary system (PBS) was demonstrated in all patients. The transverse diameter of dilated common bile ducts was closely related to the length of the narrow segment of the distal common bile duct. Common bile ducts had not dilated despite the anomalous junction of PBS during the follow-up period, ranging from 2 to 12 years after choledochocysto -jejunostomy in 7 patients. The present studies indicate that no abnormal junction of PBS but stenosis of the distal common bile duct may be etiologically responsible for the choledochal cyst.

Age Factors↗
PubMed1984

Modified hepatic portal enterostomy for biliary atresia.

Macroscopic and microscopic studies of the portal tract in liver specimens obtained at autopsy from 5 noncorrectable biliary atresia patients were performed. The studies disclosed that major intrahepatic bile ducts had disappeared for variable distances in noncorrectable biliary atresia patients. However, the topographic relationship between intrahepatic bile ducts and blood vessels was just the same as in normal livers. On the basis of these studies, we preformed more extensive portal exploration in order to get closer to the obstructed ends of major intrahepatic bile ducts. Hepatic portal enterostomy was also modified to avoid obstruction of the explored area by the jejunal wall to be anastomosed The results of 7 patients who received the new operation were encouraging with complete loss of jaundice in 6 of 7 patients.

Bile↗
PubMed1984

An electron microscopic study of acute promyelocytic leukemia with chloroma.

Tumor forming acute promyelocytic leukemia (APL) is rare and only three cases have been documented. However, there are no reports on either the chloromatous character or electron microscopical analysis. The present paper dealt with a light, electron microscopic and histochemical study of the tumor of APL in a 55-year-old Japanese male. The tumors found in the anterior mediastinum and right lower extremity. He died from respiratory disturbance and hydrothorax due to obstruction of the pulmonary truncus by the mediastinal tumor. In electron microscopy, the tumor cells showed dilatation, colloracious pattern and honey-comb-like structure of rough endoplasmic reticula (RER) and parallel array-arrangement of smooth endoplasmic reticula (SER). These abnormalities of ER are the same as those recently recognized in leukemic cells in APL. Furthermore, the intercellular junctions composed of opposing dense patches of the cytoplasmic plasmalemma were frequently found between the more immature tumor cell of the mediastinum.

Endoplasmic Reticulum↗
PubMed1984

Studies on the metabolism of diltiazem in man.

The human urinary metabolites of diltiazem were analyzed by thin-layer chromatography (TLC) and gas chromatography-mass spectrometry. Diltiazem was metabolized by deacetylation, N-demethylation, O-demethylation and conjugation. Metabolite MA, N- monodemethyl -diltiazem, was identified as a new major metabolite in human urine, and four metabolites were identified as deacetyl-diltiazem (M1), deacetyl-N- monodemethyl -diltiazem (M2), deacetyl-O-demethyl-diltiazem (M4), deacetyl-N,O-demethyl-diltiazem (M6) which were known as rat urinary metabolites. Metabolite M2, M4 and M6 were converted in part to glucuronides and/or sulfates. Unchanged diltiazem and metabolite MA were determined in human plasma and urine by TLC-densitometry. Diltiazem and metabolite MA excreted in 24-h urine were 44.4 and 48.5% of the total unconjugated form, respectively. The mean plasma level of metabolite MA was approximately one-third of diltiazem level. On the basis of these findings, a probable metabolic pathway of diltiazem in man is presented.

Adult↗
PubMed1984

Relationship between the inotropy speeds in guinea-pig myocardium and lipophilic character of cardenolides and ericaceous toxins.

Interrelation between lipophilic characters and speeds of positive inotropic effect (PIE) of cardenolides and ericaceous toxins was studied by determining both parameters of lipophilicity and inotropy speeds. The lipophilic characters of 8 kinds of cardenolides, evaluated from Rm or log k' values by means of thin layer chromatography (Rf) or high performance liquid chromatography (retention time), increased in the order of ouabain, digoxin, digitoxigenin, digitoxigenin-monodigitoxoside, digitoxigenin-bis-digitoxoside, digitoxin, alpha-acetyl-digitoxin, triacetyl-digitoxin. Lipophilic character, evaluated from Rm values of 6 kinds of ericaceous toxins, was in decreasing order of 10S-grayanotoxin II, 6-acetyl grayanotoxin I, asebotoxin I, grayanotoxin I, asebotoxin III, asebotoxin X. The speed with which PIE developed was evaluated from the time to half maximum PIE (T50) of cardenolides and ericaceous toxins at a pD2 concentration. The speed of positive inotropy of cardenolides was independent of their concentration tested in the range from half to twice the concentration of pD2, while the speeds of PIE of ericaceous toxins depended on their concentration in the same range used in case of cardenolides. Inotropy speed of these two classes of cardiotoxins correlated well with the lipophilic character: a) In the case of cardenolides, a positive and close correlation (r = 0.98) was observed between T50 and Rm. The more lipophilic the cardenolides, the more time was required to reach the fully development of PIE. b) In contrast, a negative correlation (r = -0.82, between Rm and T50) was obtained in the case of ericaceous toxins; Toxins with more lipophilic nature caused faster development of PIE. The present results can be interpreted to mean that the PIE receptor for cardenolides in myocardial cells is located on the outer surface of the sarcolemma, while that for ericaceous toxins is located on the inside of the myocardial cell.

Animals↗
PubMed1984

Serum somatomedin A in Perthes' disease.

Serum somatomedin A, determined by radioreceptor assay in 47 children with Perthes' disease, was significantly reduced as compared to normal children of the same age. Nine children underwent the 1-Dopa tolerance tests to evoke growth hormone release; a normal response was found in eight. Patients with Perthes' disease tend to be short in stature with "disproportionate skeletal growth" of the limbs; growth is less in the distal than in the proximal extremities. The low serum levels of somatomedin A suggest some growth disturbance during the development of Perthes' disease.

Adolescent↗
PubMed1984

Positive inotropic effect of 3,4-dihydro-6-[4-(3,4-dimethoxybenzoyl)-1 -piperazinyl]-2(1H)-quinolinone (OPC-8212) and mechanism of action in guinea pig ventricular myocardium.

Effects of 3,4-dihydro-6-[4-(3,4- dimethoxybenzoyl )-1-piperazinyl]-2(1H)- qu inolinone ( OPC -8212) on the isolated guinea-pig ventricular myocardium was studied measuring the force of contraction and action potential under various experimental conditions. The positive inotropic effect (PIE) of OPC -8212 was observed at a concentration higher than 10(-5) mol/l. The following circumstantial evidence led to the conclusion that OPC -8212 caused an elevated cyclic AMP level in myocardial cells thereby producing the positive inotropic effect. The positive inotropic effect of OPC -8212 was unaffected by reserpinization, propranolol and cimetidine treatments. OPC -8212 strengthened the slow response of partially depolarized papillary muscle. This suggested an increased calcium influx across myocardial cell membrane. Carbachol inhibited the positive inotropic effect of OPC -8212 on ventricular myocardium. Concentration-effect curves for isoprenaline (isoproterenol) and histamine were shifted to the left but that for dihydro-ouabain was not affected at all by OPC -8212. Rested-state contraction of guinea-pig papillary muscle was strengthened by OPC -8212 the same as dibutyryl cyclic AMP and beta-agonists.

Animals↗