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Biomedical subjects

S Higashi

Publications and source records attributed to S Higashi.

At least 253 records · Page 14Linked to original sources
PubMed1982

Formation of tight junctions in differentiating and secretory ameloblasts of rat molar tooth germs.

Forty newborn rats were perfused with Karnovsky fixative and the tight junctions in differentiating and secretory ameloblasts were examined by conventional electron microscopy and freeze-fracture replications. Pre-ameloblasts were divided into types I, II and III based on morphology. Initial indications of tight-junction formation appeared as linear aggregations of particles in type II. The apparent tight junctional strands were observed in type III and in secretory ameloblasts. Though the junctional strands were numerous and long, no complete barrier between pre-ameloblasts at their distal ends was present. Complete zonular tight junctions were first observed at the distal ends of secretory ameloblasts; at this stage, proximal tight junctions incompletely sealed the paracellular spaces around the ameloblasts. Throughout their formative processes, the tight junctional strands were engaged in forming gap junctions. The structural features of tight junctions were considered to be closely associated with the cytodifferentiation of ameloblasts and permeability in the ameloblast layer.

Ameloblasts↗
PubMed1982

Ultrastructure of odontoblasts in kitten tooth germs as revealed by freeze-fracture.

Fifteen kittens were perfused with 2.5 per cent glutaraldehyde or modified Karnovsky fixative. Distribution and structural features of the three kinds of intercellular junctions; gap junctions, macular tight junctions and desmosome-like junctions were clarified by correlated observations using thin sections and freeze-fracture replicas. Distal junctional complexes of the odontoblasts were composed of both gap and macular tight junctions and sealed extracellular spaces incompletely, because of the poor sealing capacities of macular tight junctions. Therefore, there was no predentine-pulp barrier in the odontoblast layer. Except for the junctional complex, no tight junction was observed in the odontoblasts. Gap junctions and desmosome-like junctions were found between adjacent odontoblasts and between odontoblasts and neighbouring pulp cells. Gap junctions were similar to those of many other tissues but the desmosome-like junctions were different from mature desmosomes in the epithelial cells and showed immature features. Each intercellular junction of odontoblasts is considered to form a site of intercellular communication and cell-to-cell attachment.

Animals↗
PubMed1982

Detection of human osteosarcoma-associated antigen(s) by monoclonal antibodies.

Hybrid cell lines have been derived from a fusion between mouse myeloma cells, NS1, and spleen cells from mice immunized with freshly resected osteosarcoma cells from an untreated patient. Of the 276 hybrids obtained, five secreted antibodies which bound to osteosarcoma tissues but not to autologous skin fibroblasts. The antibodies from three of these five hybrids, OST6, OST7, and OST15, reacted with all of five osteosarcoma tissues and with one chondrosarcoma tissue but not with other malignant or benign tumors. Tests of various normal tissues were negative, except for weak binding to a subpopulation of chondrocytes in articular cartilage. The reciprocal binding inhibition test showed that OST6, OST7, and OST15 antibodies were directed against different antigenic determinants.

Animals↗
PubMed1981

Adsorption of 14C-labeled gramicidin S on cell of bacteria.

Gramicidin S (GS) containing 14C-labeled proline was synthesized by a solid-phase method, and the labeled GS dihydrochloride was obtained as crystals. The labeled GS exhibited same antibacterial activity as natural GS. Strains sensitive to GS (B. subtilis and S. aureus) and an insensitive strain (E. coli) were treated with the labeled GS, and the amount of the labeled GS adsorbed on the cells was measured. GS was adsorbed rapidly on the cells of the sensitive strains; the amount adsorbed increased linearly with GS concentration up to 1-1.5 microgram/ml, and at a lower rate at above 1.5 microgram/ml. GS molecules covered most of the cell surface at the minimum inhibitory concentration of 1.5 microgram/ml; the number of molecules adsorbed per cell was 1.3-1.4 x 10(6). No GS was adsorbed by the insensitive strain.

Adsorption↗
PubMed1981

[Clinical findings of cefoxitin in the treatment of serious infections and the prevention of postoperative infections (author's transl)].

UNLABELLED: This clinical trial was designed to evaluate the efficacy, safety and patient tolerance of cefoxitin in 23 patients who were admitted to the hospital from March 1980 to November 1980. The daily dose of cefoxitin for 21 adult patients (ages ranged from 26 to 74 years old) were 6 g for the treatment of infections, and 2 to 6 g for the prevention of infections by either direct or intermittent intravenous infusions. Two children were given 100 mg/kg of cefoxitin either by direct or intermittent intravenous infusions 2 to 3 times a day in divided doses. SUMMARY OF FINDINGS: I. Treatment of intracranial infections 1. A 60-year-old man with a brain abscess was admitted to the hospital after the unsuccessful treatment with a cephalothin for 9 days. After, the initiation of therapy with cefoxitin, given 6 g a day for 3 days, the abscess was surgically removed. On the second day of treatment with cefoxitin following the operation, his highest temperature was 37.0 degrees C and was normal on the third day of treatment. He was discharged after 12 days after the surgical procedure. 2. A 56-year-old woman with cerebrospinal rhinorrhea and meningitis after the transsphenoidal removal of pituitary microadenoma responded satisfactorily to therapy with cefoxitin, given 6 g a day for 14 days after the unsuccessful treatment with a cephalothin. II. The prevention of infections following surgical operation of the central nervous system 1. Seventeen patients undergoing surgical procedures were treated with cefoxitin for the prevention of postoperative infections. None of the 17 patients developed postoperative infections. 2. A 53-year-old man undergoing repair of cerebrospinal rhinorrhea in the possibly contaminated area was successfully treated with cefoxitin, given intravenous 2 g every 8 hours for 10 days without meningitis having developed. III. The treatment and prevention of complications 1. A 74-year-old comatose male with a brain stem concussion, who was expectorating insufficiently and had difficulty swallowing and developed into pneumonia as a complication. He was successfully treated with cefoxitin, given intravenous 6 g a day for 2 weeks. 2. A 26-year-old male with a brain stem concussion complicated by pneumonia and a urinary tract infection was successfully treated with the same dose regimen of cefoxitin as the previous patient. 3. The prevention of complications A 58-year-old male with pontine glioma undergoing a tracheotomy was administered cefoxitin for the prevention of pulmonary complication. He died of pontine glioma after the three-month treatment. IV. Side effects Results of skin sensitivity tests given prior to the administration of cefoxitin were negative in all of the 23 patients. Neither anaphylaxis nor other allergic reactions or thrombophlebitis occurred with the intravenous administration of cefoxitin. No abnormalities in blood, hepatic function or renal function were observed. Anorexia occurred in 1 patient who was given cefoxitin, 6 g a day.

Adult↗
PubMed1980

Promotion of infection thread formation by substances from Rhizobium.

An extrinsic substance (ES-6000) was isolated from the periplasmic space of Rhizobium trifolii (strain 4S) cells by osmotic shock, using a high-density sucrose solution. This substance promoted infection thread formation in root hairs of white clover when inoculated together with the infectious strain (4S). However, ES-6000 obtained from another rhizobial species and from strain A1, which is a noninfectious mutant strain obtained from strain 4S, did not have this effect. The promoter in the ES-6000 from strain 4S is a relatively small molecule since it passed through a hollow-fiber membrane (molecular weight, 6,000). This substance was also recognized as an R(f) 0.1 fraction by paper chromatography. Sucrose was effective in promoting nodulation and root elongation.

Journal Article↗
PubMed1980

Scanning Electron Microscopy of Rhizobium trifolii Infection Sites on Root Hairs of White Clover.

White clover root hairs which were inoculated with Rhizobium trifolii 4S (infectious strain) contained infection threads which were observed by light microscopy and scanning electron microscopy. Three morphological types of root hairs retaining infection threads were recognized. The bacteria were strongly attached between the surfaces of two plant cell walls as follows: between surfaces of a root hair tip curled back on itself, between a protuberance from a root hair and its cell surface, or between two root hair tips clinging together. An anatomical analysis documented the attachment site of the infection thread sheath from the inside of the root hair cell.

Journal Article↗