PubMed Health⌕ Search

Biomedical subjects

H Gotoh

Publications and source records attributed to H Gotoh.

At least 127 records · Page 7Linked to original sources
PubMed1984

Simulation of axoplasmic transport.

We have analysed a kinetic model of axonal transport by simulating experimental tracer profiles. The existence of three phases of axoplasmic transport is assumed: fast anterograde, slow anterograde and retrograde. Each phase has its characteristic velocity. Transported materials are postulated to shift between these phases. Also catabolism and sequestration of material is allowed for in our model. Thus, we have set up equations which contain axonal transport, diffusion and cross-over terms. The rate constants of material shifts were determined by computer fitting to experimental data. Best-fitted values of the rate constants for transfer of material between the fast and slow phases were both 2 X 10(-5) sec-1, while the rate constants for transfer between the fast and retrograde phases were both 1 X 10(-5) sec-1. The rate constant of material loss from the slow phase to the extracellular space was 1 X 10(-6) sec-1. The material shift between the slow and retrograde phases was negligibly small. These data show that there is exchange of material between the fast and slow phases and between the fast and retrograde phases. However, there is no significant exchange between the slow and retrograde phases. Diffusion was found to have only a minor effect on the profiles. The velocity of the fast anterograde track in cold-blooded animals was predicted to be around 200 mm/day, or, in other words, to be close to experimentally observed values of the fast anterograde component of axonal transport.

Animals↗
PubMed1984

[Cell kinetic study of human gastric cancers--using an in vitro 3H-thymidine labeling method].

For the purpose of investigating cell the kinetics of human gastric carcinoma, the distribution of 3H-thymidine labeled cells and the labeling index were evaluated in biopsy specimens obtained from 52 patients with gastric cancer, using an in vitro labeling technique. Adenocarcinomas were scattered with labeled cells, while in carcinoid speciners labeled cells were confined to the periphery of tumor cell nests. Characteristically, small-sized cells were exclusively labeled with 3H-thymidine in signet-ring cell carcinomas but signet-ring cells bearing a large amount of mucin were not. Thus signet-ring cells could be regarded as cells in a differentiated condition which have lost their prolife-rating capability. The labeling index of gastric cancers ranged from 10 to 20% in most cases although it varied greatly from case to case (2.2-40.8%). The values of the labeling index were correlated with neither the degree of histological differentiation, macrascopic appearance nor the depth of mural invasion of carcinomas.

Adenocarcinoma↗
PubMed1983

The fibrillar network in the cytoplasm of squid giant axon extracted with saponin.

Skinned nerve fiber was prepared by treating a giant axon of squid with saponin. Filamentous networks and membranous organelles such as vacuoles, smooth membranes and mitochondria were present after the extraction. Ruthenium red staining of the extracted tissue showed dense fibrillar networks in the cytoplasm that correspond to the "microtrabeculae" or "cytoskeleton" reported by other investigators. Our method of preparation, thus, gives further evidence that these structures are not the result of artifactual condensation or precipitation. The present results also indicated that the networks are composed of acid mucopolysaccharides and/or mucoproteins. The density of microtubules was not changed by the extraction per se, but the number of microtubules remaining after extraction decreased by alteration of environmental conditions such as low temperature (4 degrees C), or the presence of Ca++ (1 mM), Mg++ free medium or colchicine (1 mM). These conditions are known to inhibit axonal transport. The usefulness of our extracted cytoplasm as a model of microtubule-related physiological functions is discussed.

Animals↗
PubMed1983

Experimental hyperlipidemia and atherosclerosis induced by cholesterol diet in SPF Japanese white rabbits.

Experimental hyperlipidemia and atherosclerosis induced by a cholesterol diet in SPF male and female rabbits (JW/KBL) were investigated by the determination of the lipid contents of the plasma, liver and thoracic aorta; determination of morphological changes of the aortic arch by head angiography; and computer tomography of the brain. Rabbits were fed the diet that contained 1% cholesterol for eight weeks. The plasma lipid levels began to rise from two weeks after the cholesterol diet was started, reached the peak four to six weeks later, and then fell in both males and females at eight weeks. The cholesterol of the high density lipoprotein in male rabbit plasma was slightly increased by the cholesterol diet, but not in female rabbits. An increase in the total cholesterol (TC) and triglyceride contents of the liver and an increase in the TC and phospholipid contents of the thoracic aorta were observed at the eighth week. Histological examination of the aortic arch showed marked lipid vacuoles under the endothelial cells, noticeable lipid inclusions in the smooth muscle cells of the intima and granular prominences on the internal surface of the aorta. Head angiography of rabbits fed the cholesterol diet revealed a constriction of the lumina of several arteries due to the lipid depositions. These results suggest that hyperlipidemia and atherosclerosis can be produced at the eighth week using SPF rabbits fed on a cholesterol diet.

Animal Feed↗
PubMed1983

[Effect of trapidil on experimental hyperlipemia and atherosclerosis induced by cholesterol diet in SPF Japanese white rabbits].

The effect of trapidil on experimental hyperlipemia and atherosclerosis induced by 1% cholesterol diet in SPF male rabbits (JW/KBL) was investigated by the determination of the lipid contents of the plasma and thoracic aorta and examination of morphological changes in the aorta. Trapidil inhibited the increase of total lipid (TL), total cholesterol (TC), free cholesterol (FC) and phospholipid (PL) by the cholesterol diet in all groups. The level of cholesterol (HDL-C) and phospholipid (HDL-PL) in high density lipoprotein (HDL) remained unchanged after the cholesterol diet and trapidil administration. The atherogenic index (TC-HDL-C/HDL-C, PL-HDL-PL/HDL-PL) was improved by the inhibition of TC and PL by the administration of trapidil. A morphological study of the aorta showed that trapidil inhibited lipid deposition. A microscopic observation of the intima by Sudan III stain showed that inhibition of lipid deposition corresponded with the quantity of trapidil administration. An observation of aorta using transmission electron microscopy (TEM) showed that trapidil inhibited the presence of form cells due to HCD. This inhibition corresponded with the quantity of trapidil administration; and no form cells were seen in the 50 mg/kg-administered group. An observation of intima using scanning electron microscopy (SEM) showed that trapidil inhibited the irregularly elevated regions by HCD. The structure of intima in the 50 mg/kg-administered group was similar to that of the control groups. The observation of the head angiogram showed that trapidil improved the stenosis in the lingual and temporal arteries which was caused by HCD.

Animals↗
PubMed1982

Specificity of axonal transport in C2, a histaminergic neuron of Aplysia californica.

Several labeled neurotransmitter substances or precursors ( [3H]histamine, [3H]serotonin, and [3H]choline) were injected with pressure into the cell body of C2, an identified putative histaminergic neuron in the cerebral ganglion of Aplysia in order to study the selectivity of axonal transport. We examined transport of these substances along the posterior lip nerve which contains one of the 3 extraganglionic axons of C2. The distribution of radioactivity along this axon indicated that some of the [3H]histamine is moved by fast transport, and some by diffusion. The velocity at which [3H]histamine moved along the axon was estimated at approximately 50 mm per day at 23 degrees C. The movement was slower at lower temperatures, and was partially inhibited by colchicine. Transport was selective: 6 h after injection of [3H]histamine into the cell body of C2, most of the radioactivity that appeared in axons was in the form of histamine. In contrast, equal amounts of the labeled amine and its metabolite, gamma-glutamylhistamine, were found in the cell body. Fast transport was not observed when [3H]serotonin or [3H]choline were injected. Subcellular fractionation experiments after injection showed that [3H]histamine was enriched in particulate fractions; [3H]gamma-glutamylhistamine was recovered only in the soluble fraction. Packaging of [3H]histamine in C2 was not affected by treatment with reserpine; in contrast, subcellular fractionation experiments indicated that reserpine blocks the uptake of [3H]histamine into vesicles in the giant cerebral neuron, an identified serotonergic Aplysia cell.

Animals↗
PubMed1982

Diminution of chemically induced lung neoplasia in mice by phenobarbital pre-treatment.

Pre-treatment of 21-day-old ICR/Jcl mice with 75 micrograms/g of phenobarbital significantly reduced the yields of lung tumors induced by 4-nitroquinoline-1-oxide (4NQO) and furylfuramide. Dimethylbenz[a]anthracene (DMBA)- and urethane-induced lung tumorigenesis was also reduced, but was not significantly different from that in mice receiving only the carcinogen. However, 6 consecutive treatments with phenobarbital (40 micrograms/g) in adult mice greatly reduced urethane-induced lung tumorigenesis. Post-treatment with an equal dose of phenobarbital showed neither diminution nor enhancement of tumorigenesis.

4-Nitroquinoline-1-oxide↗
PubMed1982

Hydrophobic-ionic chromatography: its application to microbial glucose oxidase, hyaluronidase, cholesterol oxidase, and cholesterol esterase.

Glucose oxidase from Aspergillus niger, hyaluronidase from Streptomyces hyalurolyticus, and cholesterol oxidase and cholesterol esterase from Pseudomonas fluorescens were effectively adsorbed on an Amberlite CG-50 column, when the cell-free cultured medium or the cultured medium with cell extract and without cell debris was applied without desalting but at pH less than or equal to 4.5. At the acidic pH, all the ion-exchange groups (-COOH) exist in the protonated form; the adsorption is not due to electrostatic attraction, but to hydrophobic interaction. The enzymes thus adsorbed were effectively eluted by increasing pH, at which the ion-exchange groups became dissociated. This type of adsorption-elution is called hydrophobic-ionic chromatography. By a single run of chromatography, glucose oxidase, hyaluronidase, cholesterol oxidase, and cholesterol esterase were purified 30-fold, 12-fold, 45-fold, and 20-fold with yields of 82%, 83%, 80%, and 90%, respectively. This indicates that hydrophobic-ionic chromatography on an Amberlite CG-50 column is effective for the purification of various enzymes, provided that they are stable at the acidic pH.

Aspergillus niger↗
PubMed1981

Vascular architecture and intestinal hematopoietic nests of two cyclostomes, Eptatretus burgeri and ammoncoetes of Entosphenus reissneri: a comparative morphological study.

Vascular architecture and the structure of the intestinal hematopoietic centers of two cyclostomes, the hagfish Eptatretus burgeri and the ammocoetes larva of Entosphenus reissneri, are compared. Blood cells of the hagfish are generated in hematopoietic nests that develop around intestinal veins established primarily for transport of absorbed nutrients. In ammocoetes, on the other hand, blood cells are generated in hematopoietic nests of the typhlosole, closely associated with venous sinusoids developing around the longitudinally oriented mesenteric artery of the typhlosole. A collateral vein of the mesenteric artery is completed in the typhlosole after metamorphosis. Since the spleen of higher vertebrates develops in relation to establishment of the collateral vein of the largest foregut artery, the intestinal hematopoietic nests of ammocoetes may be regarded as a model of the primitive form of the spleen of higher vertebrates. Hematopoiesis in the hagfish intestine is not related to establishment of a collateral vein; hence "primitive spleen" or "intestinal spleen" may be improper terms in reference to the intestinal hematopoietic tissue of the hagfish. Morphological characteristics of the hematopoietic nests of the two cyclostomes are essentially the same. Blood cells of these nests are generated in the intervenous tissue, supported by interstitial connective tissue cells and reticulin fibers. Granulated cells are the most common type in the primitive hematopoietic nests. No definitive erythrothrombocytopoiesis has been identified. Lymphocytes have not been observed in the hagfish; however, small lymphocytes have been observed in the vascular lumen of sinusoids around the hematopoietic nests of ammocoetes. These lymphocytes probably originate outside of the typhlosole.

Animals↗
PubMed1980

Hemodialysis-associated asthma in a renal failure patient.

In a renal failure patient, asthma developed after 1 year hemodialytic treatment. The attack was exclusively associated with each hemodialysis. Skin test to the usual allergen such as house dusts or pollens was negative. The provocation test by inhaling acetate solution or oral intake of acetic acid was positive resulting in an increase in the pulmonary resistance, or asthmatic attack. This asthma disappeared completely after substitution of acetate in the hemodialysis by the use of a bicarbonate dialysate. Acetate might therefore precipitate the attack of asthma.

Acetates↗
PubMed1979

Staining and relative determination of elemental contents by the laser microprobe.

An improved laser microprobe procedure is developed and applied to the measurement of calcium content in microareas of right and left subepicardial muscles. The staining of canine cardiac muscles by Methylene Blue solution (1% w/v) was found to improve sampling efficiency. Elemental content is proportional to T-1/gamma, where T is the transmittance of the characteristic emission line of the element of the photographic plate and gamma is its contrast. In the present system, the calcium content is analyzed using T-3.2. We find that the staining of samples and the determination of T-1/gamma are useful procedures in the application of laser microprobe to the study of elemental content in biologic microareas.

Animals↗
PubMed1979

Hydrophobic-ionic chromatography. Its application to purification of porcine pancreas enzymes.

1. All the porcine pancreas enzymes tested, regardless of their pI's were adsorbed on Amberlite CG-50 (a weakly acidic cation exchange resin) at pH 4, where the ion-exchange group (carboxyl group) is not dissociated. The adsorption is hardly influenced by ionic strength. 2. At pH 4, the adsorbed enzymes were partially eluted by organic solvents such as 50% propanol. 3. The adsorbed enzymes were effectively eluted by increasing the pH from 4 to 6. Trypsin (pI 10.5) was eluted before carboxypeptidase A (pI 4.5 AND 5.3) WITH 0.5 M acetate buffer, whereas the former enzyme was eluted after the latter enzyme with 0.2 M 3,3-dimethyl glutarate buffer. However, with either buffer, the elution order of enzymes was not always the same as the order of the pI's. 4. By a single Amberlite CG-50 column chromatography of porcine pancreas extracts, kallikrein, carboxypeptidase B, deoxyribonuclease, carboxypeptidase A, and trypsin were purified 100-fold, 16-fmately 13%. The purification procedures included treatment with protamine, ammonium sulfate fractionation, treatment with acid, DE-32 cellulose column chromatography, gel filtration on Sephadex G-100, preparative polyacrylamide gel electrophoresis, and affinity chromatography on 5' AMP-Sepharose 4B. The last procedure, affinity chromatography on 5' AMP-Sepharose 4B, was useful for the removal of other dehydrogenases. The enzyme which was homogeneous, as shown by polyacrylamide gel electrophoresis, had a molecular weight of about 92,000. The optimum pH was at 10.0 and isoelectric point at 5.2. The enzyme accepted both L-fucose and D-arabinose as substrate, but was specific for NAD+ as coenzyme. Km values were 0.15 mM, 1.4 mM, and 0.07 mM for L-fucose, D-arabinose, and NAD+, respectively. A single enzyme catalyzed the oxidation of L-fucose and D-arabinose, which had the same configurations of hydroxyl groups from C-2 to C-4. The reaction products obtained with L-fucose as substrate were L-fucono-lactone and L-fuconic acid. The L-fucono-lactone was an immediate product of oxidation and was hydrolyzed to L-fuconic acid spontaneously. This reaction was irreversible. Therefore, it is likely that L-fucose dehydrogenase is involved in the initial step of the catabolic pathway of L-fucose in rabbit liver.

Amylases↗
PubMed1979

Cerebral hemodynamic changes during plateau waves in brain-tumor patients.

The plateau wave, one of the wave forms observed in patients with increased intracranial pressure, has previously been extensively investigated, but its pathophysiological aspect is as yet unclear. The authors undertook a study of cerebral hemodynamic changes while the plateau waves were observed in five brain-tumor patients. Although the number of cases studied was small, a remarkable decrease in cerebrovascular resistance was seen in all patients during the plateau waves. It is suggested that the plateau waves are caused by a marked cerebral vasodilatation. The present results support the thesis that cerebral blood volume is increased during the plateau waves. The plateau waves are closely related to the intrinsic vasomotor control of cerebral circulation, and can occur as long as cerebral vasodilating ability is maintained, irrespective of the existence of cerebral autoregulation.

Adult↗