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Biomedical subjects

K Takei

Publications and source records attributed to K Takei.

At least 145 records · Page 8Linked to original sources
PubMed1989

Putative receptor for inositol 1,4,5-trisphosphate similar to ryanodine receptor.

Inositol 1,4,5-trisphosphate (Ins(1,4,5)P3) serves as an intracellular second messenger for several neurotransmitters, hormones and growth factors by initiating calcium release from intracellular stores. A cerebellar Ins(1,4,5)P3 receptor has been characterized biochemically and shown by immunocytochemistry to be present in intracellular membranes in Purkinje cells. We show that a previously described Purkinje-cell messenger RNA encodes a protein of relative molecular mass 260,000 (260 K) with the same properties as the cerebellar Ins(1,4,5)P3 receptor. Its sequence is partially homologous to the skeletal muscle ryanodine receptor. By immunocytochemistry and electron microscopy the protein is shown to be present in all parts of the endoplasmic reticulum, including those that extend into axon terminals and dendritic spines. Our results indicate that gated calcium release from intracellular stores in muscle and Purkinje cells uses similar calcium-channel proteins localized in analogous intracellular compartments. This implies that the intracellular calcium stores in the endoplasmic reticulum of neurons extend into presynaptic terminals and dendritic spines where they may play a direct role in regulating the efficacy of neurotransmission.

Amino Acid Sequence↗
PubMed1989

Synapsins: mosaics of shared and individual domains in a family of synaptic vesicle phosphoproteins.

Synapsins are neuronal phosphoproteins that coat synaptic vesicles, bind to the cytoskeleton, and are believed to function in the regulation of neurotransmitter release. Molecular cloning reveals that the synapsins comprise a family of four homologous proteins whose messenger RNA's are generated by differential splicing of transcripts from two genes. Each synapsin is a mosaic composed of homologous amino-terminal domains common to all synapsins and different combinations of distinct carboxyl-terminal domains. Immunocytochemical studies demonstrate that all four synapsins are widely distributed in nerve terminals, but that their relative amounts vary among different kinds of synapses. The structural diversity and differential distribution of the four synapsins suggest common and different roles of each in the integration of distinct signal transduction pathways that modulate neurotransmitter release in various types of neurons.

Amino Acid Sequence↗
PubMed1989

Mosaic reconstruction of blood vessels in mouse neocortical tissue transplanted into the third ventricle of rat brain.

Newborn mouse neocortical tissue was transplanted into the third ventricle of rat brain and the reconstruction and the origin of the blood vessels were investigated by using a monoclonal antibody against mouse endothelial surface antigen-1 (MESA-1). It was clearly demonstrated that some of the blood vessels in the graft originated in the donor mouse neocortical tissue. An India ink perfusion experiment revealed that the blood was supplied to the MESA-1-positive blood vessels. Furthermore, electron microscopic immunohistochemical studies demonstrated the existence of a mosaic reconstruction of blood vessels which consisted of mouse- and rat-derived vascular endothelial cells. It was concluded that the blood vessels originating in the donor tissue and those originating in the host tissue inoculate with each other in the grafted tissue.

Animals↗
PubMed1989

Expression of Ia antigen on vascular endothelial cells in mouse cerebral tissue grafted into the third ventricle of rat brain.

The mechanisms of the immunological rejection after xenogeneic neural transplantation were investigated with special reference to the expression of class II major histocompatibility complex (MHC) antigen (Ia antigen) on the grafted tissue. Tissue from a newborn mouse cerebral cortex was transplanted into the third ventricle of a 4-week-old rat brain. Infiltration of cytotoxic T-cells into the grafted tissue was investigated immunohistochemically by using a monoclonal antibody (OX-8). The infiltration began 8 days after transplantation and continued until about 4 weeks when the tissue was completely rejected. The expression of Ia antigen was also investigated immunohistochemically. The Ia antigen was first detected in the grafted tissue at 6 days after transplantation. The Ia antigen was considered to be expressed on the vascular endothelial cells judging from the staining patterns and the location of India ink which was perfused from the host's left cardiac ventricle. The perfusion experiments with India ink also revealed that blood was supplied to the grafted tissue from 5 days after transplantation. These results suggest that the expression of Ia antigen on the vascular endothelial cells renders the grafted tissues competent to initiate and participate in the immune reaction. The results also raise a possibility that the expression of Ia antigen is triggered by blood supplied from the host brain. In addition, the results indicate that the Ia-positive blood vessels do not originate in the host brain but are intrinsic to the grafted tissue.

Animals↗
PubMed1989

[A case of Ehlers-Danlos syndrome].

Ehlers-Danlos syndrome, an inherited connective tissue disorder, is characterized by skin hyperextensibility, joint hypermobility and skin fragility. The disease is at least classified into 10 types, I to X, based on clinical features, biochemical abnormalities of the connective tissue and the mode of inheritance. A case is reported of a 6-year, 8-month-old girl who showed the features of the Ehlers-Danlos syndrome type VII. The findings were as follows: 1) Soft and velvety touch skin, characteristic joint hypermobility, talipes varus, and ventricular septal defects were present. 2) Widely set eyes, slight stabismus, epicanthal folds of the eyes, antimonogoloid slanted eyes, a broad bridge to the nose and low set ears were observed. 3) Gingival bleeding following toothbrushing, Enamel hypoplasia, high arched palate and laxity of the temporomandibular joint were present. 4) In the findings of the maxillary and mandibular dental arches, there was no tendency towards conical teeth in the deciduous dentition, and the width and length of the dental arches were remarkably narrow and short. 5) The roentogenographic findings revealed that there were no minor root deformities, pulpstones and calcification of the pulp. 6) The measurement of the width, length, and depth of the palate through moiré topography revealed that the palate was narrow and deep compared with the control. 7) As a result of cephalometric diagnosis, the nasion appeared to be protruded, therefore maxillary and mandibular seemed to be relatively retracted, and the gonial angle was obtuse. The dental management of patients with Ehlers-Danlos syndrome was discussed and reviewed.

Child↗
PubMed1989

[A statistical study of autopsies performed on cases of oral cancer: with reference to distant metastasis in tongue cancer].

1. A statistical survey of oral-cancer (tongue, maxilla, and mandible) patients on which autopsies were performed by the 2nd. Department of Pathology of Tokyo Dental College from 1964 to 1987 was carried out. Of a total of 18 autopsies in cases in which death resulted from tongue carcinoma, 11 subjects were male and 7 female. Average age was 63.4 years. This cancer occurred most frequently in individuals in the age group of 60 to 69 years. The lung was the most common (50%) site of distant organic metastasis; the next most common sites were the liver, the thyroid gland, and the diaphragm (11.1% each). Submandibular and cervical lymph nodes were the most common sites of lymphatic metastasis in cases of tongue cancer. These data were similar to those in previous reports. 2. An autopsy on a 57-year-old man who died of tongue cancer revealed a number of distant metastases in both organs and lymph nodes were reported. 3. The report includes a review of literature on distant metastasis in cases of tongue cancer.

Aged↗
PubMed1989

[Analysis of the components of the electrically evoked response (EER) of the visual system by topography and dipole-tracing].

In order to examine the possibility of the clinical application of the electrically evoked response (EER) of the visual system, we analyzed the significance of the various components of the EER by means of topography and dipole-tracing. By applying a constant electric current of 1.0mA (duration 5msec) to each eye, three rhythmical waves were recorded within 200msec from the stimulation. The peaks of these waves were named N1, P1, N2, P2, N3, P3. Among those components of EER, we found P2 to be localized in the visual cortex, though the other components did not show any specific localization. The results indicated the significance of analyzing P2 in order to further investigate the possible clinical applications of EER.

Adult↗
PubMed1987

Horseradish peroxidase study of the localization of motoneurons in the accessory nucleus (XI) of the Japanese toad.

It has been conventionally accepted that the anuran accessory nerve (nXI) only innervates the musculus cucullaris (C). However, we have found that the nXI of the Japanese toad innervated the musculus interscapularis (IS) in addition to the C. The motoneurons innervating these muscles were labelled by the intramuscular injection of horseradish peroxidase (HRP). In the accessory nucleus (XI), the motoneurons were somatotopically organized: the C motoneurons were localized more rostrally, while the IS motoneurons more caudally.

Accessory Nerve↗
PubMed1987

Distribution of motoneurons involved in the prey-catching behavior in the Japanese toad, Bufo japonicus.

Coordinated activities of several muscles in the head region underlie the prey-catching behavior of anuran amphibians. As a step in elucidating the neural mechanisms generating these activity patterns in the Japanese toad, we labelled the motoneurons innervating 8 behaviorally relevant muscles using intramuscular (i.m.) injection technique of horseradish peroxidase (HRP), and examined their localization within the motor nuclei whose boundaries were determined by HRP application to the nerve trunk. All the motoneurons innervating the two jaw closer muscles (m. masseter major, m. temporalis) and m. submentalis were localized within the rostral subdivision of the trigeminal motor nucleus. The motoneurons innervating the only mouth opener muscle (m. depressor mandibulae) were scattered throughout the facial motor nucleus. The motoneurons innervating tongue (m. hypoglossus, m. genioglossus) and hyoid muscles (m. sternohyoideus, m. geniohyoideus) appeared within the hypoglossal nucleus with distribution patterns characteristic of the target muscles. Thus, we have revealed the neuroanatomical organization of the motoneurons relevant to the prey-catching behavior.

Animals↗
PubMed1987

Ex vivo comparison of radiological and histological evaluation of early metastatic lesions of pelvic lymph nodes from carcinoma of the bladder or prostate.

To study the limitations of lymphangiography in the detection of early lymphatic spread of pelvic malignancies, we evaluated 587 lymph nodes from 23 patients with stages pN0 to 2 carcinoma of the bladder or prostate. Pelvic lymphadenectomy was performed 5 to 10 days after bipedal lymphangiography. Excised lymph nodes were separated one by one and an x-ray of each node was taken (lymphnodegram). The individual lymphnodegram was compared to the histological findings. Interpretations of lymphnodegrams from all 17 nodes with metastases were positive in 5, suspicious in 1, negative in 9 and radiolucent in 2. False negative judgments occurred chiefly because metastatic foci were microscopic. Two lymph nodes without metastasis were interpreted as positive for disease because of fat replacement of the nodes. These results indicated that lymphangiography is not suitable for the detection of early lymphatic metastases of carcinoma of the bladder or prostate.

Humans↗