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Biomedical subjects

M Akai

Publications and source records attributed to M Akai.

At least 91 records · Page 5Linked to original sources
PubMed1986

Distribution of enkephalin-like immunoreactivity in the feline heart; its interrelation with substance P- and vasoactive intestinal polypeptide-like immunoreactive nerve fibers.

Distribution of enkephalin (Enk)-like immunoreactivity in the feline heart was investigated by indirect immunofluorescence method. Enk-like immunoreactive (Enk-IR) nerve fibers and cells predominated in the atria but were rare in the ventricles. Enk-IR cells were mainly distributed near sinoatrial (SA) node and between aorta and pulmonary artery. These cells were usually grouped in clusters near blood vessels or cardiac ganglia. Some Enk-IR cells appeared to extend their processes to other Enk-IR cells, cardiac ganglia, blood vessels and rarely cardiac muscles in the atria. Furthermore, substance P (SP)- and vasoactive intestinal polypeptide (VIP)-IR nerve fibers were closely associated with some Enk-IR cells. Moreover, the distribution and morphological profiles of Enk-IR cells were very similar to those of catecholamine (CA)-containing cells.

Animals↗
PubMed1985

Immunohistochemical observation on substance P in regenerating taste buds of the rat.

The present study was performed to investigate the relationship between substance P-positive (SP-positive) nerve fibers and regeneration of taste buds in the foliate papillae of the rat by means of immunohistochemistry. It was confirmed by neurotomy that taste buds in the foliate papillae of the rat were innervated mostly (90%) by the glossopharyngeal (IXth) nerve and partly (10%) by the chorda tympani. In this experiment, the IXth nerve was sectioned distal to the petrosal ganglion. The rats were sacrificed at various intervals from 20 days to 80 days after the operation. In the course of degeneration and disappearance of taste buds, both SP-positive fibers and taste buds disappeared completely from the posterior folds of the foliate papillae 7 days after the operation. Within 22 days, regenerated SP-positive fibers began to appear in the lamina propria, and following the penetration of the fibers into the epithelium, taste bud anlagen reappeared at the bottom of the trench, and in the posterior folds at 24 days. The process of new taste bud formation extended toward the apex of the trench and to the anterior folds, which seemed to follow the regeneration in the nerve trunk. Quantitative data showed a gradual increase in the number of taste buds and taste buds containing SP-positive fibers. These findings indicate that SP might have a role in regeneration of taste buds.

Animals↗
PubMed1985

The distribution and origin of substance P-like immunoreactivity in the rat molar pulp and periodontal tissues.

Rat mandibles were fixed in Zamboni fixative and demineralized in a mixture of EDTA and fixative. Substance P-like immunoreactivity was demonstrated by indirect immunofluorescence in molar pulp, periodontal ligament and gingiva. Substance P (SP) containing nerve fibres with varicosities were observed in the pulp horn and root pulp in general located around blood vessels. Some SP-containing fibres penetrated into the predentine and dentine. In the periodontal ligament, SP fibres were localized along the blood vessels in the middle and apical regions. Many SP-containing fibres were associated with the blood vessels in the lamina propria of gingiva. After inferior alveolar nerve section, SP-positive nerve fibres in the pulp and periodontal ligament disappeared completely. In gingiva the number of SP fibres decreased but not all fibres disappeared. Removal of the superior cervical ganglion did not affect the distribution of SP-containing nerve fibres.

Animals↗
PubMed1984

Substance P-like immunoreactivity in the pulp-dentine zone of human molar teeth demonstrated by indirect immunofluorescence.

Freshly-extracted human third molars were fixed in Zamboni fixative, demineralized with the mixture of EDTA and the fixative; substance P-like immunoreactivity (SPLI) was revealed by the indirect immunofluorescence technique of Coons. Substance P (SP) was observed in the pulp-dentine zone and the dental pulp. Some of SP-containing fibres ended at the odontoblast layer and did not reach the predentine; others terminated at the predentine surface or penetrated into the predentine. In the predentine, some of SP fibres accompanied odontoblast processes and ended near the mineralized dentine; others changed course transversely at various levels.

Dental Pulp↗
PubMed1984

Ultrastructure of granular materials in rat incisor enamel organ at early maturation stage.

With scanning electron microscopy, globules were seen in inter-cellular spaces between ameloblasts with ruffled borders and papillary cells at early maturation stage. Numerous globules were located on longitudinal folds between parallel ridges on the sides of ameloblasts, but only a few in the papillary layer. In previously-scanned specimens sectioned for transmission electron microscopy, the globules were composed of finely granular material. Vacuoles containing material identical to extra-cellular granules were observed in intra-cellular portions of the ameloblasts and papillary cells.

Ameloblasts↗
PubMed1984

Mechanical properties of the electrically stimulated callus. An experiment with constant direct current in rabbit fibulae.

The investigation of the effect of direct current on the mechanical properties of experimental fractures was conducted by applying 7-10 microA of constant current to the osseous defect of the rabbits' fibulae. The fibulae were tested mechanically with the combined methods of nondestructive technique and breaking-strength measurement. The result was analyzed in relation to the volume of the newly formed callus, which was estimated by roentgenographic appearance and calculation. There is no accurate proof that an electrically stimulated callus is superior in mechanical strength. A more massive callus in a relatively earlier stage suggests that the stimulated callus may have some advantages over the nonstimulated callus.

Animals↗
PubMed1983

Scanning electron microscopy of the papillary layer of the rat-incisor enamel organ.

The enamel organ isolated from the maturation zone was treated with hydrochloric acid to remove such extracellular materials as collagen fibrils and basal lamina covering the papillary layer. Two types of the ridges were classified on the basis of their morphology and distribution: (1) globular and irregularly arranged ridges at the periphery of the early maturation zone, (2) elliptical and parallel ridges in the central part of this zone and over the whole of the late maturation zone. The fine surface structures of the ridges were characterized by numerous interdigitating cell processes.

Animals↗
PubMed1983

[Clinical features and treatment of pulmonary metastasis in osteosarcoma].

Ninety-seven pulmonary metastatic cases in 141 osteosarcoma from 1960 to 1981 were analysed. The overall cumulative 5-year survival rate of the cases was 38.1%, whereas that of the recent 41 cases with systemic chemotherapy was 56.2%. Eighty percent of pulmonary metastases were found within one year since their first visit to our clinic. It was revealed that there were positive relationship between the doubling time of the pulmonary metastases and the post-metastatic survival (p less than 0.001), and between the period from their first visit to our clinic to metastases and the post-metastatic survival (p less than 0.001). The favorable effects of the systemic chemotherapy using adriamycin, vincristine, methotrexate and cis-platinum were recognized. The thoracotomy revealed effective and five cases are living without disease for average 80.8 months after surgery.

Antineoplastic Agents↗
PubMed1983

[Determination of malignancy of cartilaginous tumors (2). Determination of malignancy by nuclear DNA contents and their distribution patterns in cartilaginous tumors].

In 40 different types of cartilaginous tumors, the number of binuclear cells was calculated and DNA content was examined using fluorescent Feulgen cytophotometric technique. In 7 enchondromas and 1 synovial chondromatosis, the DNA content was diploid in 7 and hypotetraploid in 1, and showed a unimodal normal distribution. The number of binuclear cells was 0.1-0.45%, and the mean DNA content was below 4. These cases showed no evidence of disease after curettage and bone graft. The follow-up period was from 4 years 6 months to 7 years 1 month, averaging 6 years 2 months. In 2 enchondromatoses and 2 benign chondroblastomas, the DNA content was diploid and showed a unimodal normal distribution. One chondromyxoid fibroma showed a broad-unimodal tetraploid distribution, and one benign chondroblastoma showed a broad-aneuploid distribution. The nuclear DNA content was sometimes histologically similar to that of chondrosarcoma in some benign cartilaginous tumors. In 5 secondary chondrosarcomas, the DNA content was hypo- or hypertetraploid, hexaploid, and showed broad-unimodal or broad-bimodal distribution. The number of binuclear cells was from 13% to 23%. Although the size of the nucleus was small, the number of binuclear cells was evidently numerous. The preferred treatment for secondary chondrosarcoma is principally wide resection, but amputation is sometimes indicated in cases of recurrence and large tumor size. The follow-up period was from 2 years 2 months to 18 years 11 months, averaging 9 years 11 months. All 5 patients were surviving at the time of follow-up. The DNA content in chondrosarcoma was mostly hypo- or hypertetraploid, hexaploid, or octaploid and showed broad-unimodal, broad-bimodal or broad-aneuploid distribution. The number of binuclear cells was 0.55-3.5%. The mean DNA content was proportional to the number of binuclear cells, the positive correlation between the mean DNA content and the number of binuclear cells was found (p less than 1%).

Adolescent↗
PubMed1982

Nature and distribution of mucosubstances in human mature enamel identified by enzyme electron microscopy.

Longitudinal slices of 12 freshly extracted human third molars fixed in 10 per cent neutral formalin were demineralized with 1M lactic acid. Ultrathin sections of slices were stained with ruthenium red or silver methenamine. The reaction products were mainly found in the prism sheath regions. To identify the mucosubstances, the digestion tests with chondroitinase ABC, AC, hyaluronidase and neuraminidase were performed. It was concluded that the major component of the organic matrix of inner human dental enamel is chondroitin 4-sulphate or chondroitin 6-sulphate localized in prism sheath regions and inter-crystalline spaces.

Chondroitin Sulfates↗