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Biomedical subjects

T Toyonaga

Publications and source records attributed to T Toyonaga.

26 records · Page 2Linked to original sources
PubMed1992

Prevention of autoimmune insulitis in nonobese diabetic mice by expression of major histocompatibility complex class I Ld molecules.

Nonobese diabetic (NOD) mice spontaneously develop a T-cell-mediated autoimmune disease that is similar in many respects to insulin-dependent diabetes mellitus in humans. NOD mice were shown to express major histocompatibility complex class I Kd and Db antigens. To examine the possible involvement of major histocompatibility complex class I molecules in the development of autoimmune insulitis, we attempted to express a different type of class I molecule in NOD mice by crossing C57BL/6 mice transgenic for the class I Ld gene with NOD mice. The backcross progeny expressed the Ld antigen on the peripheral blood lymphocytes at a level comparable with that of the BALB/c mice. The cell surface expression of endogenous class I and class II antigens on the peripheral blood lymphocytes was not affected. Analysis of these mice revealed that the expression of the class I Ld antigen significantly reduced the incidence of insulitis at 20 weeks of age. In situ hybridization of a biotinylated probe on mouse chromosomes showed that the Ld transgene was located in the E area of chromosome 6 with which no genetic linkage to insulin-dependent diabetes mellitus was demonstrated. These results suggest that the NOD-type class I molecules are involved in the development of insulitis in NOD mice.

Animals↗
PubMed1992

Role of the upstream region containing an intrinsic DNA curvature in the negative regulation of the phospholipase C gene of Clostridium perfringens.

The phospholipase C (alpha-toxin) gene (plc) of Clostridium perfringens was cloned into pUC19 and the effects of the upstream regions on expression of the plc gene were examined in Escherichia coli JM109. When the 0.7-kb region just upstream of the putative -35 site of the gene was deleted, production of phospholipase C increased approximately 10-fold. Northern blot hybridization analysis of the plc transcript showed that the upstream region inhibited transcription from the plc promoter. Nucleotide sequencing of this upstream region revealed that there are three periodically repeated (dA)5-6 tracts between positions -66 and -40 of the plc gene. A fragment containing this sequence showed anomalously slow electrophoretic mobility at low temperature, indicating that the region immediately upstream of the plc promoter is a locus of sequence directed DNA-bending. Nested deletions of the upstream region were created from its 5' end by exonuclease III and the effects of deletions on the expression of the plc gene were examined. When the 77-bp fragment containing the two (dA)5-6 tracts were deleted, phospholipase C production increased markedly. These results indicate that the intrinsic DNA curvature upstream of the plc promoter is involved in the negative regulation of the plc gene transcription.

Bacterial Toxins↗
PubMed1992

[Importance of lipoprotein(a) in patients with ischemic heart disease].

Elevated levels of lipoprotein(a) [Lp(a)] have been associated with an increased risk of ischemic heart disease (IHD), and higher levels of Lp(a) are associated with lesions of significantly greater severity. We have examined Lp(a), total cholesterol (TC) and high density lipoprotein-cholesterol (HDL-C) levels in patients with IHD including those with normal coronary arteries with vasospastic angina. The study population consisted of 206 patients (166 males and 40 females) who underwent diagnostic coronary angiography for known IHD. Twenty-eight patients had effort angina, 36 rest angina, 8 unstable angina and 134 old myocardial infarction. IHD patients were categorized as zero vessel disease (0VD), single vessel disease (SVD) and multi-vessel disease (MVD). To investigate the relationship between atherosclerosis and IHD, these patients were further divided into 3 groups based on angiographic findings. Eighteen patients had entirely normal coronary arteries (normal group), 24 discretely diseased coronary arteries (discrete group) and 80 diffusely diseased coronaries (diffuse group). The results were compared with those obtained from 50 healthy individuals. Lp(a) levels for IHD patients (12.4 mg/dl) were significantly higher than those of controls (7.1 mg/dl, p < 0.05). However, there were no statistical differences between 0VD (13.1 mg/dl) and MVD (12.8 mg/dl). Similarly, no statistical differences of Lp(a) values were found among the normal group (13.3 mg/dl), discrete group (12.0 mg/dl) and diffuse group (12.9 mg/dl). Mean levels of HDL-C in 0VD (51.3 +/- 13.5 mg/dl) were significantly higher than those of SVD (42.9 +/- 11.5 mg/dl, p < 0.05). However, no significant differences were observed between controls (59.5 +/- 15.3 mg/dl) and 0VD (51.3 +/- 13.5 mg/dl).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1992

Chondromalacic changes of the patella in rabbits.

Malalignments of the patellofemoral joints were artificially made in eleven rabbits using four different methods in order to generate chondromalacia of the patella. Chondromalacic changes and the location similar to the chondromalacia of the human body were generated in one joint of the patching group. According to the results of our investigation, the most reasonable etiological factor of the chondromalacia is thought to be the expansion of the medial retinaculum and capsule of the knee joint, and chondromalacia patellae may not be a precursor of osteoarthritic changes.

Animals↗
PubMed1992

The measurement of muscle strength in the hip joint expressed by the octagonal diagram.

For grasping hip joint function objectively and planning an adequate program for individual use in rehabilitation during and after the treatment for hip joint impairments, the octagonal diagram of the correct distribution of the hip joint muscle strength will be useful. The muscle strength was measured in the eight directions using the Cybex-II on the U.B.X.T. table not only on the peak torque but also on the maximum work and the maximum work/sec in eighty healthy subjects, forty of each male and female. No difference of the muscle strength between the dominant and the non-dominant legs of both male and female has shown. In the percentage of the values of the muscle strength, there are differences between the peak torque, the maximum work value and the maximum work/sec. The data obtained from this investigation will be available to judge the degree of hip joint impairment, and to make a better therapeutic program for the patients.

Female↗
PubMed1983

Substitute meniscus of Teflon-net for the knee joint of dogs.

Investigations conducted in 20 joints of 17 dogs suggest that a Teflon-net substitute meniscus preserves knee joint functions more effectively than a regenerated or absent meniscus. Teflon-net is an ideal material for meniscal replacement because it is easily obtainable, has flexibility and histo-compatibility, and is rapidly infiltrated with cells. A comparative study should be undertaken of knee joint functions with the substitute meniscus and the remains of the meniscus after partial meniscectomy before clinical use of the Teflon-net is feasible. The adhesion between the substitute meniscus and the popliteal muscle also requires further laboratory investigation.

Animals↗