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Biomedical subjects

M Saitoh

Publications and source records attributed to M Saitoh.

At least 325 records · Page 18Linked to original sources
PubMed1989

[Occlusal pattern factors influencing masticatory efficiency].

The purpose of this study was to investigate the relationship between occlusal pattern factors and masticatory efficiency. 50 subjects with normal dentition were tested to obtain the occlusal pattern standard. The simplified particle counting method, which was previously reported by Imaoka et al., was used to determine the masticatory efficiency. Measurements included 5 factors of the occlusal pattern of the habitual chewing side, including the canine of each subject: the number of occlusal contact areas, the size of each area, the number of occlusal facets of the projected area, the size of the factors of the projected area and the inclination of the occlusal facets. The correlation between the 5 factors of the occlusal pattern and the masticatory efficiency were analyzed to obtain a standard for the restoration of occlusal patterns. The results were as follows: 1. The number of occlusal contacts and the number and inclination of occlusal facet were the main factors which to influenced the masticatory efficiency. 2. The standard number of occlusal contacts and occlusal facets were 15 and 25 respectively. 3. Although the inclination of the occlusal facets of premolars was slightly bigger than those of molars, the standard inclination of the occlusal facets was 25-30 degrees. 4. There was no significant correlation between the masticatory efficiency and the projected area of the occlusal contacts and facets. 5. The classification of occlusal facets should be considered, because of the inclination of the occlusal facets which appear at the same areas of the cusp point, the fossa and the marginal ridge was 10-15 degrees, and the inclination of the other areas of occlusal pattern was bigger.

Dental Occlusion↗
PubMed1989

Differences in urate metabolism between normouricemia and hyperuricemia in coronary heart disease in man.

We examined hyperuricemia in patients with coronary heart disease. In 85 patients with coronary sclerosis confirmed by coronary angiography, the serum urate level (6.08 +/- 1.60 mg/dL) was not different from that in subjects with normal coronary arteries (6.47 +/- 1.69 mg/dL). The incidence of hyperuricemia in patients with coronary sclerosis was 26%, and was significantly correlated with diuretics, obesity and hypertriglyceridemia, but not with hypertension or hypercholesterolemia. To elucidate the mechanism of urate metabolism in coronary sclerosis, we separated coronary sclerosis patients without complicating factors into hyperuricemics and normouricemics, and studied urate metabolism in comparison with subjects with normal coronary arteries. We found that normouricemics with coronary sclerosis had decreases in the filtered urate load and urate clearance with a normal urate-creatinine clearance ratio. Hyperuricemics with coronary sclerosis had decreases in urate clearance and urate-creatinine clearance ratios, but the filtered urate load was similar to that in normouricemics. It is suggested that in coronary sclerosis patients, normouricemics had a low glomerular filtration of urate with normal tubular urate transport, whereas hyperuricemics had enhanced tubular reabsorption of urate without any difference of urate filtration from normouricemics.

Coronary Disease↗
PubMed1989

[Evaluation of masticatory efficiency and the analysis of occlusal pattern factors using computer image processing method].

The purpose of this study was to evaluate the newly developed computer-assisted image processing method. We applied this method for the evaluation of masticatory efficiency and the analysis of occlusal pattern factors: the number and the size of occlusal contact areas, the number of and the size of the projected facets. We compared this new method with our conventional one which is the simplified particle counting method using a sieve and measuring the occlusal pattern factors with a planimeter. The results were as follows: 1. It is possible to count the number of particles within an optional range of size with the new method. 2. The new method may be used with minimum error for the measurement of occlusal pattern factors. We believe that this newly developed computer-assisted image processing method can be put to practical use for clinical evaluation of masticatory efficiency and analysis of occlusal pattern factors.

Dental Occlusion↗
PubMed1989

[Survey on oral and maxillofacial injuries in contact sports and diffusion of mouthguards].

Recent reports have shown an increase of oral and maxillofacial injuries caused by sports activities. In European and American countries, mouthguards are the popular measure against these injuries. The purpose of this study was to survey the rate of incidence of oral and maxillofacial injuries caused by contact sports, the diffusion and the evaluation of mouthguards and the interest in mouthguards in Japan. Questionnaires were sent to 244 Rugby football teams in Aichi prefecture and 27 American football teams in the Tokai area. We received replies from 153 Rugby football teams and 17 American football teams, and the results were as follows: 1) The rate of incidence of oral and maxillofacial injuries was 239 players out of 4721 players, which means 5.1% in Rugby football and 22 players out of 428 players, which means 5.1% in American football. 2) The diffusion of mouthguards was 20 out of 153 teams in Rugby football and 16 out of 17 teams in American football. And most of them are using commercially available mouthguards. 3) Almost all teams were not satisfied with their mouthguards and complained of speaking difficulties, discomfort and easy dislocation. 4) Almost all teams desire the improvement of mouthguards. 5) Teams with no experience of mouthguards were very much interested in the use of mouthguards but they do not have enough information about mouthguards. 6) We have to enlighten players and their instructors about mouthguards and diffuse the use of mouthguards more positively to contact sports players.

Adolescent↗
PubMed1989

[A case of bronchogenic cyst of the esophagus].

A case of bronchogenic cyst in the lower end of the mediastinal esophagus was reported. A 46 years old man had an abnormal mass shadow at the right cardiophrenic angle revealed by the annual X-ray examination. A 5.5 X 4.5 X 5 cm sized intramurally located tumor was successfully removed. As it was a monolocular cyst that microscopically lined with ciliated columnar epithelium and contained cartilage in the wall, but that was not covered by two muscle layers, the cyst was diagnosed as bronchogenic. The post-operative course was uneventful. The authors discussed the differential diagnosis of this lesion, especially about cysts which were situated in the esophagus. To avoid confusion, a certain diagnostic criteria based on the histological findings was suggested.

Bronchogenic Cyst↗
PubMed1989

[Effect of thermotherapy on human esophageal carcinoma in culture and clinical cases].

Multidisciplinary treatment for advanced esophageal carcinoma, which is not resectable in many cases, has become an important subject to study. We have reported the effectiveness of thermotherapy in treatment of esophageal carcinoma by basic experiments using three cell strains of human esophageal carcinoma designated as SGF-3,4,5. Based on the results of the basic experiments, we have performed thermotherapy combined with radiotherapy, chemotherapy and immunotherapy on cases of advanced esophageal carcinoma since October 1985. As for the basic experiment, proliferation of SGF-3 was inhibited at more than 40 degrees C, SGF-4 at more than 41 degrees C and SGF-5 at more than 42 degrees C. We did not observe the recovery of the growth of SGF-3 after heating at 41 degrees C for 72 hours and 42 degrees C for more than 24 hours. And the growth of SGF-4 after heating at 42 degrees C for more than 48 hours did not recover either. No recovery of the growth of SGF-5 after heating at 42 degrees C for 72 hours was noted. Based on the data, combined therapy was performed in 12 patients with advanced esophageal carcinoma. The evaluation of the local response to the combined thermotherapy revealed CR in five cases, PR in five and NC in two.

Aged↗
PubMed1989

[Report of a case of intracranial metastases from malignant spinal cord astrocytoma].

A 22-year-old female with intracranial metastases after partial removal of malignant spinal cord astrocytoma followed with radiation therapy was reported. 20 cases of spinal cord astrocytoma with intracranial metastases were reviewed. Almost all cases were malignant. Malignant spinal cord astrocytoma seems to have much tendency to metastasize to the brain.

Adult↗
PubMed1989

[A case of right intermediate bronchial stenosis due to an injury eighteen years before].

A 20 year-old man was admitted to our hospital suffering from fever and cough due to bronchiectasis. He had been injured in automobile accident 18 years before. The subsequent bronchography revealed a marked stricture of the right intermediate bronchus with post-stenotic bronchiectasis. Right middle and lower lobectomy was performed. Postoperatively, pneumonia improved, and pulmonary function was preserved. There is no agreement on criteria indicating the need for bronchial reconstruction in cases like this, because evaluation is difficult whether inflammatory changes in the lobes intending to the reimplant may be reversible. In our case, we considered that recurrent pneumonia and bronchiectatic changes of the right lower lobe were contra-indications to bronchial reconstruction.

Adult↗
PubMed1988

Evidence against in vivo presence of 2-(2-furoyl)-4(5)-(2-furanyl)-1H-imidazole, a major fluorescent advanced end product generated by nonenzymatic glycosylation.

The reaction of protein amino groups with glucose leads to the formation of a stable Amadori product via a Schiff base adduct, which is further converted to advanced glycosylation end products (AGE) with color and unique fluorescence characteristics. 2-(2-Furoyl)-4(5)-(2-furanyl)-1H-imidazole (FFI) was recently identified as a major fluorescent compound (Ponger, S., Ulrich, P.C., Bencsath, F.A., and Cerami, A. (1984) Proc. Natl. Acad. Sci. U.S.A. 81, 2684-2688). Its in vivo and in situ presence was further demonstrated by radioimmunoassays (Chang, J.C.F., Ulrich, P.C., Bucala, R., and Cerami, A. (1985) J. Biol. Chem. 260, 7970-7974). In the present study the occurrence of FFI in AGE-proteins was reassessed. The radioimmunoassay using anti-FFI antibody and high performance liquid chromatography failed to detect FFI in AGE samples obtained from bovine serum albumin, poly-L-lysine, oligo-L-lysine, and L-lysine. Even after acid hydrolysis or proteinase K digestion, FFI was undetectable. To our surprise, however, the addition of ammonia to these acid hydrolysate led to the production of FFI, suggesting the importance of acid hydrolysis and subsequent reaction with ammonia for the generation of FFI. This observation was fully supported by model experiments using AGE-samples prepared by incubating glucose with monoaminocarboxylic acids such as beta-alanine, gamma-aminobutyric acid, and epsilon-aminocaproic acid. Thus, a nonfluorescent FFI precursor is produced by acid hydrolysis, and its conversion to fluorescent FFI occurs upon subsequent reaction with ammonia, the evidence against the presence of FFI in AGE-proteins.

Ammonia↗
PubMed1988

Endocytic uptake of nonenzymatically glycosylated proteins is mediated by a scavenger receptor for aldehyde-modified proteins.

Long term incubation of proteins with glucose, named the Maillard reaction (Maillard, L. C. (1912) C. R. Acad. Sci. (Paris) 154, 66-68), gives rise to advanced glycosylation end product (AGE) with fluorescence, color, as well as cross-linked properties. The receptor-mediated endocytosis of AGE-proteins by macrophages was reported (Vlassara, H., Brownlee, M., and Cerami, A. (1985) Proc. Natl. Acad. Sci. U.S.A. 82, 5588-5592). The present study on the binding of AGE-bovine serum albumin (BSA) to rat peritoneal macrophages and sinusoidal liver cells demonstrated the presence of a saturable, high affinity receptor for AGE-BSA with Kd = 2.4 x 10(-7) M (macrophages) and 2.1 x 10(-7) M (sinusoidal cells). The cellular binding of AGE-BSA and its endocytic uptake by these cells were competitively inhibited by BSA preparations modified with aliphatic aldehydes such as formaldehyde or glycolaldehyde, ligands known to be specific for a scavenger receptor for aldehyde-modified proteins (Horiuchi, S., Murakami, M., Takata, K., and Morino, Y. (1986). J. Biol. Chem. 261, 4962-4966). These ligands also had a profound in vivo effect on the plasma clearance of 125I-AGE-BSA as well as its hepatic uptake. Thus, endocytic uptake of AGE-proteins by macrophages appeared to be mediated by a scavenger receptor for aldehyde-modified proteins. This provides evidence for the biological importance of the scavenger receptor in eliminating senescent macromolecules from the circulation.

Animals↗
PubMed1988

Inhibition of human platelet secretion and of Ca2+, calmodulin-dependent protein phosphorylation by the antiallergic agent GMCHA.

Calcium ion-dependent interaction with purified calmodulin (CaM), of a potent inhibitor of histamine release from mast cells, trans-4-guanidinomethylcyclohexanecarboxylic acid p-tertbutylphenylester (GMCHA), was investigated using 5-(dimethylamino)-1-naphthalenesulfonyl-calmodulin (dansyl-CaM). GMCHA undergoes a fluorescence increase with the Ca2+-dansyl-CaM complex but there is no significant change in the dansyl-CaM fluorescence with GMCHA, up to a 10 microM in the absence of calcium ion. This suggests that binding of GMCHA to CaM is Ca2+-dependent on the apparent Kd is approximately 1 microM. GMCHA suppressed the fluorescence of the hydrophobic probe 8-anilino-1-naphthalenesulfonate (ANS), in the presence of the Ca2+-CaM complex, with an IC50 value of 3 microM. [3H]N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide (W-7) bound to the purified CaM was displaced, in a concentration dependent manner by GMCHA, the Ki value of GMCHA against the binding of W-7 to CaM was 2.3 microM, and there was a selective inhibition of the Ca2+-CaM induced activation of enzymes such as myosin light chain kinase. Increasing the CaM concentration in the presence of Ca2+ overcame the GMCHA-induced inhibition of myosin light chain kinase activation, with a Ki value of 2.7 microM. GMCHA at these concentrations is effective in inhibiting the release of histamine from mast cells. Moreover, this compound suppresses platelet secretion and relaxes vascular strips, at concentrations similar to those seen with the CaM interacting action and characteristic of CaM antagonists such as W-7. GMCHA also inhibits the Ca2+, CaM-dependent myosin light chain phosphorylation of human platelets. These results suggest that GMCHA, a potent inhibitor of histamine release from mast cells, suppresses platelet secretion, relaxes vascular smooth muscle and inhibits Ca2+, CaM-dependent protein phosphorylation, all at similar concentrations.

Adenosine Triphosphate↗
PubMed1988

Structure of the rat renin gene.

We have isolated the renin gene from a Sprague-Dawley rat genomic library and determined its complete nucleotide sequence. The single rat renin gene is approximately 11,000 bases in length and consists of nine exons and eight introns. The amino acid sequence predicted from the genomic sequence indicates that the rat renin precursor consists of 402 amino acid residues, and shows 85%, 82% and 68% homology to the mouse Ren-1 and Ren-2, and human renins, respectively. The canonical promoter "TATA" boxes, TATAAA and TAATAA, are found 27 and 57 base-pairs upstream from the putative cap site, respectively. Several attractive regulatory sequences analogous to glucocorticoid, estrogen receptor-binding sites, cAMP-responsive element and SV40 enhancer core sequences were noted in the 5'-flanking region of the gene. In the first intron, segments with an average size of 38 base-pairs containing a NcoI site are present at 46 tandem repeats within 1710 base-pairs. A "CA" element consisting of (CA)27 was identified in intron 3. Furthermore, intron 8 contains a sequence that shows about 93% homology to that of the neuronal identifier sequence.

Amino Acid Sequence↗
PubMed1988

Selective inhibition of cyclic AMP phosphodiesterase from various human tissues by milrinone, a potent cardiac bipyridine.

We observed the effects of milrinone, an inotropic agent prescribed to treat congestive heart failure, on cyclic nucleotide messenger systems in various human tissues in vivo. Cyclic nucleotide phosphodiesterases (PDEs) from the human heart were separated into three isoforms, FI, FII and FIII, by DEAE-cellulose chromatography. Milrinone proved to be a potent and selective inhibitor of human cardiac FIII PDE, a "low Km" enzyme for cyclic AMP (cAMP-PDE). The IC50 value for the inhibition of FIII PDE was 0.42 microM, while those of FI and FII PDEs, "high Km" enzymes, were 38 and 19 microM, respectively. Kinetic studies showed that milrinone inhibited the activity of FIII PDE, competitively with respect to cAMP, and the Ki was 0.15 microM. Milrinone in doses to 100 microM had no effect on human cardiac cAMP-dependent protein kinase and adenylate cyclase. The activity of cAMP-PDEs from human platelets and the aorta, as well as that from heart, were potently inhibited by milrinone, with much the same IC50 values. Cyclic AMP-PDEs from human kidney, liver and lung were not readily inhibited by milrinone, and the IC50 values of cAMP-PDEs from these tissues were about 7-30-fold higher than that from heart. On the other hand, papaverine had a relatively lesser selectivity for any of the cAMP-PDEs. All these results suggest that milrinone exerts inotropic effects by inhibiting cAMP-PDE selectively in the human heart tissues and that this compound can be used to evaluate different forms of cAMP-PDEs present in human tissues.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1988

Two phosphorylated forms of myosin in thrombin-stimulated platelets.

Three forms of 20-kDa myosin light chain (MLC), unphosphorylated, monophosphorylated, and diphosphorylated MLC (designated 20K, 20K-P, and 20K-PP) were demonstrated in thrombin-stimulated human platelets by two different gel electrophoretic methods: in the presence of glycerol urea or in two dimensions (isoelectric and sodium dodecyl sulfate). The diphosphorylation of platelet 20-kDa MLC increased, dose dependently, up to 0.4 U/ml thrombin and reached 25% of platelet 20-kDa MLC. After mono- or diphosphorylated 20-kDa MLC from thrombin-stimulated platelets was digested with trypsin, the analysis using two-dimensional peptide mapping demonstrated that two different sites were phosphorylated by MLC kinase and protein kinase C, as noted in the case of 12-O-tetradecanoylphorbol-13-acetate-stimulated platelets (M. Naka, et al. (1983) Nature (London) 306, 490-492). The more rapid monophosphorylation was catalyzed preferentially by MLC kinase while the slower and additional phosphorylation was catalyzed mainly by protein kinase C. These results suggest the importance of distinguishing multiple site phosphorylation of 20-kDa MLC in thrombin-activated human platelets.

Binding Sites↗
PubMed1988

Antiarrhythmic effects of alpha-adrenoceptor antagonists in guinea pig ventricular myocardium.

Antiarrhythmic effects of alpha-adrenoceptor antagonists were assessed in the reserpinized guinea pig ventricular myocardium. Both bunazosin (1 to 3 x 10(-7) M), a new alpha 1-adrenoceptor antagonist, and yohimbine (1 to 3 x 10(-7) M), another adrenoceptor antagonist, suppressed the transient depolarization and triggered activity induced by a train of rapid stimuli in the solution containing low potassium ion (K+), high calcium ion (Ca2+) and strophanthidin (1 to 5 x 10(-7) M). Bunazosin (3 x 10(-6) M) abolished the facilitatory effect of hypoxia on beta-adrenoceptor mediated abnormal automaticity. To clarify the mechanisms underlying the antiarrhythmic properties of alpha-adrenoceptor antagonists, their electrophysiologic effects on the fast and slow action potentials were investigated. Alpha-adrenoceptor antagonists (bunazosin, yohimbine and phentolamine) suppressed the slow response in a dose-related manner. The voltage-dependent block and use-dependent block of the maximal rate of rise (Vmax) of action potentials by bunazosin (10(-5) to 10(-4) M) and yohimbine (10(-6) to 10(-5) M) were studied. The analysis of the onset and recovery kinetics from the use-dependent block of drugs showed that both bunazosin and yohimbine act as slow kinetic drugs. It is concluded that alpha-adrenoceptor antagonists seem to have an antiarrhythmic effect through the inhibition of fast sodium ion (Na+) and slow Ca2+ currents of the cell membrane independently of blockade of myocardial alpha-adrenoceptors.

Action Potentials↗