Search PubMed⌕ Search

Biomedical subjects

S Masumi

Publications and source records attributed to S Masumi.

At least 55 records · Page 3Linked to original sources
PubMed1990

[Morphological characteristics of the alveolar ridge of edentulous jaws].

Impression taking is essential step in prosthetic clinical work and a tray of an appropriate size and form must be selected to obtain accurate impressions. In taking impressions of edentulous jaws, in particular, the morphology of the alveolar ridge must be grasped precisely. Length and width of the alveolar crest therefore were measured and their correlation was examined. 1. The coefficients of correlation of the maximal length of the alveolar crest with width between the posterior margins of the alveolar crest, with the width between the alveolar crest at the first molars, and with the width between alveolar crest at the canines were r = 0.20, 0.43, 0.38, respectively, for the upper jaws, and r = 0.14, 0.01, 0.02, respectively, for the lower jaws. No significant correlation was found. 2. Significant correlation was found between the posterior margins of the alveolar crest and the width between the alveolar crest at the first molars and the width between the alveolar crest at the canines (r = 0.66, 0.70) for the upper jaws. 3. Significant correlation was found between the posterior margins of the alveolar crest with the width between the alveolar crest at the first molars (r = 0.76) for the lower jaws.

Alveolar Process↗
PubMed1990

Subclasses of IgG H chain expressed in the rheumatoid synovium.

A complementary DNA (cDNA) library was constructed from a 72 year-old patient's synovium removed at surgery of the left knee replacement. The number of independent clones was found to be 1.1 x 10(6). Eighty-seven (0.3%) positive plaques were obtained from 30,000 plaques of this library using a genomic probe containing a constant region of IgG1. In these positive plaques, ten independent clones were purified and the subclasses were identified by DNA sequences near the "Hinge" region. Seven clones were identified as gamma 2, two clones as gamma 1 and one clone as gamma 4 respectively. Measurement of the serum IgG subclasses in this patient indicated increased IgG2. We conclude that some patients of rheumatoid arthritis exhibit an increased level of a unique IgG subclass.

Aged↗
PubMed1989

Analysis of abutment tooth movement utilizing mandibular kinesiography (MKG). Part 2. Effects of clasp design in unilateral free-end denture.

The three-dimensional dynamic movement of the abutment tooth was successfully analyzed on a simulation model utilizing the mandibular kinesiography. When the unilateral free-end denture retained by the RPA, RPI or Aker's clasp was subjected to various directions of loads, the abutment tooth was inclined mainly by the sliding displacement of the denture over the alveolar ridge and the lever action around the denture. The Aker's clasp assembly induced the largest tooth movement. The RPA clasp generally exhibited similar tendencies to the Aker's clasp, showing a larger tooth inclination in the disto-buccal direction. The RPI clasp seemed to be preferable for protecting the periodontal tissues from damage associated with unfavorable tooth movements since it induced less distal tooth inclination.

Dental Abutments↗
PubMed1989

Ultrastructural study of articular cartilage in experimental pyogenic arthritis.

Ultrastructural changes of the articular cartilage at the early stage of experimental pyogenic arthritis were studied by electron microscopy. The superficial zone of the cartilage at the site of the cartilage-synovium junction demonstrated far more changes than those at the site of the free surface of the articular cartilage. Changes were observed at the cartilage-synovium junction as early as four hours after the intraarticular injection of the infecting organism. The most interesting finding was migration of erythrocytes and polymorphonuclear leucocytes into the superficial zone of the cartilage at the early stage. The pericellular matrix in the middle zone became so loose in some areas that collagen fibrils were partially exposed after three days. The naked collagen fibrils were tapered, nicked and irregular in size after seven days.

Animals↗
PubMed1989

Bipolar hip arthroplasty in rheumatoid arthritis.

Bipolar hip arthroplasty with bone grafting was performed on 25 joints with rheumatoid arthritis from 1981 to 1985. The results and roentgenographical progress of the grafted bone were followed for a minimum of two years, the longest follow-up examination occurring six years after the operation. The clinical score was assessed by the hip rating score of the Japanese Orthopaedic Association, which assigns a maximum of 100 points. The preoperative clinical score ranged from 22 to 59 points (mean, 42.6). The postoperative score improved to a range of 65-92 points (mean, 72.8). Of 24 hips examined, 21 (87.5%) were painless. As measured serially from the roentgenograms made immediately after the operation, the overall distance of central migration in 24 hips was 0-8.5 mm (average, 2.7 mm). The overall distance of superior migration in 24 hips was 0-10 mm (average, 3.7 mm). A single massive bone graft using extracted femoral head was considered to be better than bone fragments as the procedure for acetabular reconstruction during bipolar hip arthroplasty in rheumatoid arthritis.

Adult↗
PubMed1989

The lateral approach compared with the volar approach for exposure of the hook of the hamate.

Two cases of delayed union of the hook of the hamate were satisfactorily treated by excisional surgery. The volar surgical approach through the palm is common, but to expose the hook some hypothenar muscles and cardinal ligaments must be divided. Care must be taken to avoid injury of the motor and sensory branches of the ulnar nerve that occur close to the hook. The lateral approach between the abductor digiti minimi muscle and the fifth metacarpal bone is easier and less traumatic. This approach is also safer for the ulnar neurovascular bundle, which is protected by volar retraction and the hypothenar muscles. The lateral approach is advantageous unless the injury is complicated by ulnar nerve palsy or flexor tendon injury.

Carpal Bones↗
PubMed1988

Effect of norepinephrine on consumption of oxygen in perfused skeletal muscle from cold-exposed rats.

The effect of norepinephrine on the consumption of O2 was studied in the skeletal muscle in the perfused hindlimbs of rats that had been kept at 4 degrees C for 5-25 days. 1) Basal rates of consumption of O2 and release of lactate were not affected by exposure to cold. 2) The stimulation of consumption of O2 by norepinephrine increased in the perfused hindlimbs of rats exposed to cold for 10-25 days, with a maximum stimulation at 20 days. The response to norepinephrine decreased markedly in hindlimbs perfused with propranolol or phentolamine. Phenylephrine, in the presence of 0.5 nM isoproterenol, stimulated the consumption of O2 at concentrations as low as 0.5 microM, with a maximum at 5 microM, in hindlimbs from the group exposed to cold for 20 days. 3) Ouabain inhibited the stimulation of consumption of O2 by norepinephrine. Norepinephrine caused a net release of K+ in control muscle but a net uptake of K+ by muscle from the group exposed to cold for 20 days. The results suggest that the calorigenic responsiveness to norepinephrine increases in skeletal muscle during acclimation of the rat to the cold, both alpha- and beta-adrenergic actions are involved in the calorigenic effects of norepinephrine, and the increased activity of the Na+-K+ ATPase under the influence of norepinephrine may be involved in the calorigenic action of norepinephrine on the skeletal muscle of cold-acclimated rats.

Acclimatization↗
PubMed1987

Effect of 5-azacytidine on malignant transformation of a mutant derived from the mouse BALB/c 3T3 cell line resistant to transformation by chemical carcinogens.

BALB/c 3T3 and its derivative MO-5, isolated as a monensin-resistant clone, showed a very low rate of spontaneous malignant transformation. Treatment of BALB/c 3T3 cells with benzo(alpha)pyrene, 4-nitroquinoline-N-oxide, N-methyl-N'-nitro-N-nitrosoguanidine, N-methyl-N-nitrosourea, or UV light irradiation significantly enhanced the rate of transformation, whereas the treatment of MO-5 cells with these carcinogens had only a slight if any effect. Exposure of MO-5 as well as BALB/c 3T3 to 5 or 10 microM 5-azacytidine for 3 to 7 days significantly increased the number of transformation foci. The Luria-Delbrück fluctuation test showed that spontaneous mutation frequency (mutants/cell/generation) was 1.2 X 10(-6) for BALB/c 3T3 and 7.1 X 10(-7) for MO-5, respectively, when appearance of cadmium-resistant clones was tested. N-Methyl-N'-nitro-N-nitrosoguanidine enhanced induced mutation frequency of ouabain-resistant and cadmium-resistant mutants of BALB/3T3 but it only slightly enhanced that of MO-5. Methylation status of DNA of MO-5 was compared with that of BALB/c 3T3 by comparing the cleavage patterns generated by the isoschizomeric restriction enzymes HpaII and MspI. DNA of MO-5 was found to be more methylated than that of BALB/c 3T3 in the vicinity of c-myc as well as the metallothionein-I gene. Aberrant DNA methylation in MO-5 and the cellular sensitivity to transformation by chemical carcinogens or 5-azacytidine are discussed.

4-Nitroquinoline-1-oxide↗
PubMed1983

Spondyloepiphyseal dysplasia tarda with progressive arthropathy.

The clinical and roentgenographic manifestations of six cases suffering from spondyloepiphyseal dysplasia tarda with progressive arthropathy are presented. The roentgenographic features consist of generalized platyspondyly and varying degrees of epiphyseal involvement with conspicuous enlargement of both ends of the short tubular bones of the hands. This disorder appears at an earlier age, and is more crippling than the usual form of spondyloepiphyseal dysplasia tarda. It is suggested that orthopaedic measures are essential for all patients with this disorder, as profound disability may be expected by progressive involvement of the major joints.

Adolescent↗
PubMed1983

Utilization of the extensor retinaculum in the radiocarpal joint of rheumatoid wrists.

Synovectomy and debridement were combined with use of pedicled flaps of the extensor retinaculum as interposition material in the radiocarpal joint to cover the eroded articular surfaces of the radius and ulna in rheumatoid wrists. The technique was devised for the purpose of preventing postoperative osseous ankylosis of the radiocarpal joint. Results were satisfactory in 13 of 17 wrists operated on during the period from 1974 to 1979 and followed up for 38 to 84 months (average, 61 months).

Adult↗