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Biomedical subjects

Y Takeuchi

Publications and source records attributed to Y Takeuchi.

At least 1,027 records · Page 57Linked to original sources

Immunohistochemical demonstration of serotonin-containing nerve fibers in the cerebellum.

The localization of serotonin (5-HT)-immunoreactive nerve fibers in the cerebellum of the rat and cat was investigated by means of the peroxidase-anti-peroxidase (PAP) method using highly specific antibodies to 5-HT. Serotonin-containing nerve fibers were distributed throughout the entire cerebellum including the deep cerebellar nuclei, while 5-HT-positive neuronal somata were not detected in the cerebellum of either species. A different pattern of 5-HT innervation was found among the three layers of the cerebellar cortex. There were also interspecific differences in the pattern of distribution of 5-HT. In the rat, the pool of 5-HT nerve fibers mainly consisted of tangential elements, which were predominant in the molecular layer, while in the cat only a few 5-HT fibers were found in the molecular layer of the cerebellar cortex; dense networks of 5-HT nerve fibers were present in the granular layer. Some differences are evident in the pattern of distribution of 5-HT fibers in cerebellar regions classified on an anatomical and functional basis.

Animals↗

Neurotoxicity of petroleum benzine compared with n-hexane.

Petroleum benzine is one of the mixtures of organic solvents containing n-hexane. The occurrence of polyneuropathy in the workers using petroleum benzines is attributed mainly to n-hexane, though other hydrocarbons present are also suspected of having some neurotoxicity or some potential which could modify the neurotoxicity of n-hexane. The present experiment was performed in order to clarify the toxicity of petroleum benzine to the peripheral nerve and compare it with that of n-hexane. Forty rats were randomly divided into five groups. The groups were exposed to 200 ppm n-hexane, 500 ppm n-hexane, and petroleum benzine vapor containing 200 ppm n-hexane or 500 ppm n-hexane, together with aliphatic and aromatic hydrocarbons for 12 h a day for 24 weeks. The body weight, motor nerve conduction velocity, motor distal latency, and mixed nerve conduction velocities were measured before exposure and every 4 weeks of exposure. A rat from each exposed group was histopathologically examined after 24 weeks' exposure. The function of the peripheral nerve was conspicuously impaired by 500 ppm n-hexane, slightly impaired by 200 ppm n-hexane and petroleum benzine containing 500 ppm n-hexane, and even less impaired by petroleum benzine containing 200 ppm n-hexane. Degenerations of the myelin sheaths and axons were demonstrated in all exposed groups upon examination of the revealed tail nerves. Thus, the experiment revealed that petroleum benzine could impair the peripheral nerves, while some components of petroleum benzine were considered to inhibit the neurotoxicity of n-hexane.

Alkanes↗

Immunohistochemical demonstration of EC cells in rat gastrointestinal tract.

Selective immunohistochemical demonstration of enterochromaffin (EC) cells in the rat gastrointestinal tract has been carried out, using a highly specific rabbit antiserotonin (5-HT) serum and the unlabeled peroxidase-antiperoxidase complex (PAP) technique. The daily profile of the EC cell density was also studied using this method. No significant change was recorded.

Animals↗

Immunohistochemical demonstration of serotonin nerve fibers in the cat neurohypophysis.

Distribution of the serotonin nerve fibers in the neurohypophysis of adult cats was demonstrated using the peroxidase-antiperoxidase method. The serotonin nerve fibers were distributed in the internal and external layers of the infundibulum, terminating on the wall of the capillary loops and the outer surface of the external layer. A small number of the fibers scattered about in the posterior lobe penetrated the intercellular spaces in the intermediate lobe.

Animals↗

Immunohistochemical studies on the serotonergic innervation of the pia mater.

The direct innervation of the pial blood vessels by serotonin neurons has been demonstrated with a modified peroxidase-antiperoxidase technique in the mammalian central nervous system. The pia mater covering the ventrolateral surface of the medulla oblongata is innervated by numerous varicose serotonin fibers originating from the serotonin neurons of the lower brainstem. Scattered serotonin fibers were observed in the pia mater in every part of the brain and spinal cord.

Animals↗

Immunohistochemical demonstration of serotonin nerve fibers in the olfactory bulb of the rat, cat and monkey.

The distribution of serotonin (5-HT) positive fibers in the olfactory bulb of the rat, cat and monkey was studied using the peroxidase-anti-peroxidase (PAP) immunohistochemical method and highly specific antibodies to 5-HT. In general, 5-HT fibers were present throughout all layers in the olfactory bulb of these species except for the olfactory nerve layer and different as well as restricted laminar patterns of 5-HT distribution were observed. There were also species-related differences in the pattern of 5-HT distribution, in each layer. The most notable species difference was apparent in the glomerular layer of the main olfactory bulb. In case of the rat and cat, a very dense plexus of 5-HT fibers was observed to be diffuse in the glomerulus, while in the monkey, the distribution of 5-HT fibers was scanty and partial, as was seen in the accessory olfactory bulb of the rat.

Animals↗

Determination of microscopic ionization constants and microscopic stacking equilibrium quotients of adenylyl(3' --> 5')adenosine.

Using the basic ionization constants for a pair of isomers, m1ApA and Apm1A, and the measured values for the overlapping pK values of ApA, the microscopic ionization constants and intramolecular stacking quotients for the monoprotonated ApA were estimated. The results indicate that, in contrast to the case of GpG, ApA did not exhibit preferential protonation on either site of 3'- and 5'-linked nucleoside bases and neither enhanced nor diminished stacking was observed for ApA and ApA as compared to ApA.

Journal Article↗

His-bundle electrogram in the convalescent stage of inferior myocardial infarction complicated with complete A-V block.

Twelve patients with inferior wall myocardial infarction complicated with complete atrioventricular block during the acute stage were studied. The His-bundle electrogram was studied in the convalescent stage at an average of 6 months after the acute attack. The age of the patients was 62 +/- 16 years. The width of the QRS complex was within the normal range and the PR interval was less than 200 msec. AH time was 74 +/- 18 msec (mean +/- SD). No split H activity was observed. HV time however, was significantly prolonged in the 12 patients; 54 +/- 12 msec vs. 42 +/- 9 msec in the control group (p less than 0.02). Five patients had HV time equal to or more than 60 msec. Intra-His block was suggested to exist in a high frequency in the patients who had previous complete AV block during the acute stage of myocardial infarction of the inferior wall.

Blood Pressure↗