Search PubMed⌕ Search

Biomedical subjects

T Kawata

Publications and source records attributed to T Kawata.

At least 199 records · Page 11Linked to original sources
PubMed1990

Role of the harderian gland in immunoglobulin A production in chicken lacrimal fluid.

The role of the Harderian gland (HG) in the production of immunoglobulin, especially IgA, was investigated. Lacrimal immunoglobulin almost disappeared after surgical removal of the HG and immunoglobulin produced by HG cells was detected in saliva but not in the trachea. Immunoglobulin production occurred in HG cell culture in vitro and it consisted mostly of IgA; the production of IgM and IgG was very low. These findings indicate that lacrimal IgA is produced locally in the HG and lacrimal IgG and IgM are mostly transported from the blood.

Animals↗
PubMed1990

[Psychological study of questionnaire relating to dentition and orthodontic treatment].

Concern of patients for dentition and receptivity of orthodontic treatment was studied by a general population questionnaire. Subjects (general population) consisted of elder elementary school boys and girls (157), junior high school (274) and high school students (90) and adults (45) in Tokushima, Kagawa and Kouchi prefectures. Twenty-three questions, previously selected from forty-seven using the Quantification III for orthodontic patients. Furthermore, ten questions were selected from these twenty-three using the same method and categorized into two groups. Each category was given a meaning. Five answers in each category were given marks: a positive answer was 'point one' and a negative one was 'point zero'. Mean points in each category were compared with eight groups according to age and sex. AIC (Akaike Information Criterion) was used for statistical analysis. The following results were obtained. 1. Two categories were independently identified. One had meaning in relation to concern for dentition and other had meaning in relation to receptivity of orthodontic treatment. 2. Orthodontic patients showed significantly higher points than general population for concern and receptivity. 3. Females in each group showed higher points for concern of dentition in general population, but males showed higher points for receptivity of orthodontic treatment. 4. Junior high school and high school students showed significantly lower points in two categories, in addition, males in this group showed lower points in these categories. 5. There were no significant differences between subjects in three prefectures. It is possible for general population to evaluate instructions or education methods for promoting interest in dentition by this study. Orthodontic patients will also be encouraged by the present study to receive orthodontic treatment.

Adolescent↗
PubMed1990

[An attempt of experimental study to clarify the rearrangement mechanisms of transseptal fibers during mechanical retention periods].

The present investigation has been attempted to clarify the remodeling mechanisms of transseptal fibers during mechanical retention periods. Orthodontic forces of 25 gm and 150 gm were respectively applied to upper molars of rats for 10 days and retained mechanically. Retention periods were 10, 30 and 60 days. The trend of transseptal fibers after these retention periods was observed by the methods of histology and histochemistry. Histological study was observed rearrangement of fibrous tissue by light and electron microscopy and histochemical one was observed acid phosphatase activity. The following results were obtained: 1. Very little was observed about the rearrangement of transseptal fibers by the orthodontic force applied for 10 days. 2. The mechanical retention was kept longer, stretched transseptal fibers were slowly restored to original shape. This means transseptal fibers were gradually rearranged. 3. The collagen containing fibroblast and fibroblast characterized by abundant rough endoplasmic reticulum and Golgi complex were ultrastructurally observed. 4. The reaction of ACPase activity in some fibroblasts can be observed. These results suggest that transseptal fibers were rearranged during mechanical retention periods and that fibroblasts were engaged in this remodeling by synthesizing and degrading collagen fibers.

Animals↗
PubMed1990

[A study to establish the model of transseptal fibers in vitro by human gingival fibroblast].

The present study was attempted to establish the model of transseptal fibers in vitro to clarify the remodeling mechanisms of the fibers during orthodontic treatment. Human premolars were transversally cut. The thickness of films was 150 microns and a pair of dental rings was placed at intermediate of 500 microns in tissue culture dishes. Human gingival fibroblasts were seeded in these dishes and cultured. Culturing of these cells were changed at 1, 5, 10 and 20 days and used to histological observation. The following results were obtained: 1. It was observed that human gingival fibroblasts and fibrillar materials oriented approximately the surfaces of sliced teeth and extended the process of cells along the direction from sliced teeth to another one. The bridges of cells and fibers between two sliced teeth were completed after 10 days culturing. 2. The fibrillar materials were examined by TEM and bundles constructed from banded fibrils which each band was 60 nm in diameter. The red fibers were stained with Van Gieson's stain method and so many red fibers filled in the space between the two sliced teeth. This suggests that the most of fibrillar materials were collagen fibers formed from human gingival fibroblasts. The structural materials were assumed to be resembled to transseptal fibers in vivo. This culture system is usefull to study the remodeling mechanisms of transseptal fibers in tooth movement.

Bicuspid↗
PubMed1990

[Finite element analysis on physiological mobility of individual teeth].

The initial movement of the tooth was investigated by the finite element method. The mechanical properties of the periodontal membrane were estimated from the results of the simulation. The analysis was made by using an 8 point isoparametric finite element method. The upper central incisor with an axial directional load was simulated. The concept of the apparent elastic modulus was introduced to the stress-strain relation of the soft tissue, that is, soft tissue such as the periodontal membrane and the gingiva was considered to have stress dependent elastic moduli. At the first stage of the simulation, the stress and strain distributions in the paradentium were calculated by the conventional method. From the next stage, the apparent elastic moduli for the soft tissue were introduced to the calculation, that is, the elastic moduli for the soft tissue were computed from the calculated equivalent stresses of the previous stage. The calculations were repeated until the displacement values converged. The initial displacement of the tooth was not proportional to the applied load but showed a non-linear relationship. The relationship between load and displacement was approxiated by the n-th power equation. These results were in agreement with the clinical experimental results. The periodontal membrane is built up of different elastic moduli. The elastic moduli were low at the alveolar edge and the root apex. The equivalent stresses of the periodontal membrane were marked low in the alveolar edge and the root apex. In conclusion, the concept of the apparent elastic modulus is useful to investigate the initial movement of the tooth and estimate the mechanical properties of the periodontal membrane.

Computer Simulation↗
PubMed1990

[Clinical results, graft patency and flow reserve capacity of multiple coronary artery bypass with bilateral or sequential internal thoracic artery grafts].

Multiple coronary artery bypass grafting (CABG) was performed utilizing the internal thoracic arteries (ITA) in 87 patients ranging in age from 3 to 76 years. Bilateral ITAs were used in 67, sequential grafting was performed in 16, and the combination of both techniques was applied in 4 patients. Twelve patients had coronary arterial obstructions due to Kawasaki disease (mean age 9.7 +/- 3.3 years) and the remaining 75 patients had atherosclerotic coronary artery disease (mean age 53 +/- 10 years). Triple vessel disease and left main trunk disease occupied 85% of the patients. The number of grafts was 2 to 5 per patient with an average of 3.2 +/- 0.7 per patient. In bilateral ITA grafting, the combination of the RITA to LAD and LITA to LCX was most frequently used, and in sequential grafting, the LITA-diagonal artery-LAD was the most common use. There were no early or late mortalities in the present series. The patency rates for the RITA and LITA were 93% and 96%, respectively, and those of sequential grafting were 100% in both the proximal and distal anastomoses. The clinical outcome of multiple CABG with ITAs was quite satisfactory, and the bilateral ITAs could be used in the very wide range of patient's age from 3 to 76 years. In addition, blood flow reserve provided by bilateral ITAs was equivalent to that of the SVG alone or SVG plus ITA on the basis of the result of coronary sinus flow (CSF) measurements during exercise, and thus complete revascularization of the left ventricle could be accomplished by multiple CABG with ITAs.

Adult↗
PubMed1990

[Percutaneous balloon valvuloplasty of a stenosed bioprosthesis (Carpentier-Edwards xenograft) in the tricuspid valve position].

Two patients with increasing stenosis of a bioprosthesis in the tricuspid valve position were treated by percutaneous balloon valvuloplasty (PBV). Tricuspid valve replacement with a Carpentier-Edwards xenograft and mitral valve replacement with a Duromedics mechanical valve had been performed in both of them 2 to 3 years prior to PBV. Echocardiographic studies revealed tricuspid bioprosthetic stenosis with a prolonged pressure half time. After PBV, the calculated valve area and cardiac index increased and the pressure half time was shortened, although improvement of clinical symptoms was not apparent. Complications related to the procedure did not occur. Further studies are required to determine the indications and to see the long term results of PBV on stenosed bioprosthesis in the tricuspid valve position, but for the moment, we consider PBV be tried with caution for a stenosed bioprosthesis in the tricuspid valve position before the decision for re-replacement of the prosthesis.

Bioprosthesis↗
PubMed1989

A comparison of competitive enzyme immunoassay and precipitin inhibition tests in the analysis of polysaccharide antigenic determinants of oral streptococci.

A rapid and convenient method of competitive enzyme immunoassay (EIA) was explored for the immunological analysis by MAbs of polysaccharide antigens prepared from the mutans group of streptococci, and optimal conditions for it were established. These included the concentrations of antigen, monoclonal antibodies (MAbs) and labelled antibody, temperature, pH and reaction time. The results were compared with those obtained by precipitin inhibition tests using the classical quantitative precipitin reaction, and they were found to be consistent with the latter method. It was concluded that the EIA system can be extended to the immunological study of polysaccharide antigens of oral streptococci using MAbs which perform poorly in precipitation reactions.

Animals↗
PubMed1989

Function of the hexameric sequence in the cauliflower mosaic virus 35S RNA promoter region.

The hexameric sequence ACGTCA functions in transcriptional regulation of wheat histone genes. The cauliflower mosaic virus (CaMV) 35S RNA promoter has the same hexameric sequence, and mutation analyses confirmed that the hexamer contributed greatly to transcription from the 35S promoter when a test gene with this promoter was introduced into sunflower cells. Electrophoretic mobility shift assays revealed the existence of a nuclear protein(s) in sunflower cells which is homologous to the HBP-1b that has been identified as binding to the 35S promoter in wheat. These results provide evidence of the involvement of the hexameric sequence and the HBP-1b-like DNA binding protein(s) in transcription from the 35S promoter.

Base Sequence↗
PubMed1989

A protein that binds to a cis-acting element of wheat histone genes has a leucine zipper motif.

The structure and function of transcription factors of higher plants was studied by isolating cDNA clones encoding a wheat sequence-specific DNA binding protein. A hexameric nucleotide motif, ACGTCA, is located upstream from the TATA box of several plant histone genes. It has been suggested that this motif is essential for efficient transcription of the wheat histone H3 gene. A wheat nuclear protein, HBP-1 (histone DNA binding protein-1), which specifically binds to the hexameric motif, has previously been identified as a putative transcription factor. A cDNA clone encoding HBP-1 has been isolated on the basis of specific binding of HBP-1 to the hexameric motif. The deduced amino acid sequence indicates that HBP-1 contains the leucine zipper motif, which represents a characteristic property of several eukaryotic transcription factors.

Amino Acid Sequence↗
PubMed1989

Fatty acid cyclooxygenase activity stimulated by transforming growth factor-beta in mouse osteoblastic cells (MC3T3-E1).

Prostaglandin (PG)E2, a bone-resorption factor, was released essentially as the sole arachidonate metabolite by an osteogenic cell line cloned from mouse calvaria (MC3T3-E1). Transforming growth factor (TGF)-beta (1 ng/ml) or epidermal growth factor (EGF) (10 ng/ml) markedly stimulated the endogenous PGE2 synthesis in the presence of 5% newborn bovine serum. The serum could not be omitted even if both TGF-beta and EGF were added simultaneously. The PGE2 synthesis started after a 1-h lag phase, and reached a maximum at about 3 h after the addition of TGF-beta. The presence of TGF-beta enhanced the cyclooxygenase activity (arachidonic acid----PGH2) assayed with the microsomes or the immunoprecipitate from the solubilized enzyme. The TGF-beta-stimulated PGE2 synthesis was blocked by translation and transcription inhibitors. Furthermore, Western blot analysis using anti-cyclooxygenase antibody demonstrated a higher level of cyclooxygenase in the TGF-beta-treated cells than in the nontreated cells. These experimental results suggested an induction of cyclooxygenase by TGF-beta as previously reported for EGF (K. Yokota et al. (1986) J. Biol. Chem. 261, 15,410-15,415).

Animals↗
PubMed1989

Nucleotide sequences of the 5.8S rRNA gene and internal transcribed spacer regions in carrot and broad bean ribosomal DNA.

Nucleotide sequences of the first and second internal transcribed spacers (ITS1 and ITS2, respectively) of ribosomal DNA (rDNA) from two dicot plants, carrot and broad bean, were determined. These sequences were compared with those of rice, a monocot plant, and other eukaryotic organisms. Both types of ITS region in some species of Angiospermae were the shortest among all eukaryotes so far examined and showed a wide range of variation in their G+C content, in contrast to a general trend toward very high G+C content in animals. Phylogenetic relationships of plants with animals and lower eukaryotes were considered using the nucleotide sequences of carrot and broad bean 5.8S rDNA that were determined in the present study, together with that of wheat 5.8S rRNA, which has been reported previously.

Animal Population Groups↗
PubMed1989

Comparative characterization of spirosomes isolated from Lactobacillus brevis, Lactobacillus fermentum, and Lactobacillus buchneri.

Spirosomes, cytoplasmic fine spirals, were isolated and purified from Lactobacillus brevis ATCC 8287, L. fermentum F-1, and L. buchneri ATCC 4005, and their morphological, biochemical, and immunological properties were investigated. The spirosomes of these lactobacilli were morphologically indistinguishable from one another, and they had the same buoyant density of 1.320 g/cm3 in CsCl. All of the spirosomes were composed of a single protein, spirosin, with an apparent molecular weight of about 95,000 for L. brevis and L. fermentum and of about 96,000 for L. buchneri as estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The spirosins from the three lactobacilli were compared by peptide mapping on SDS-PAGE after cleavage with N-chlorosuccinimide and limited proteolysis with Staphylococcus aureus V8 protease. The peptide map of the L. brevis spirosin was identical with that of the L. fermentum spirosin, whereas it was markedly different from the L. buchneri spirosin. The amino acid composition of the L. brevis spirosin was almost similar to that of the L. fermentum spirosin, while it differed appreciably from the L. buchneri spirosin. Using antiserum against the L. brevis spirosin, immunodiffusion test revealed that the antigenicity of the spirosomes from L. brevis was identical with that from L. fermentum, whereas it was partially different from that from L. buchneri.

Amino Acids↗
PubMed1989

Characterization and reassembly of a regular array in the cell wall of Clostridium difficile GAI 4131.

The cell wall of Clostridium difficile GAI 4131 was revealed by electron microscopy to have an outer layer composed of a nearly square array and contained the two major proteins with molecular weights of 38 kDa and 42 kDa. The properties and reassembly of the two major proteins into the regular array were investigated. When the isolated cell walls were treated with hydrophobic bond-disrupting agents or a chelating agent specific for Ca2+, the two major proteins were effectively removed and the regularly arranged outer layer disappeared. The amino acid composition of the two major proteins differed from each other. The two major proteins also gave different peptide maps from each other upon proteolysis with Staphylococcus aureus V8 protease. The major proteins solubilized from the isolated cell walls with 8 M urea or 4 M guanidine hydrochloride could be reassembled into open-ended cylinders possessing the native regular pattern by dialysis against neutral buffer containing 5 mM CaCl2. The reassembled cylinders purified by centrifugation on a Percoll density gradient were composed of almost equal amounts of the 38 kDa and 42 kDa proteins and freed from the other proteins. These results suggest that the regular array in the outer cell wall layer is constructed from the two major cell wall proteins and requires Ca2+ for its assembly.

Amino Acids↗
PubMed1989

Isolation and characterization of cytoplasmic fibrils from treponemes.

Electron microscopy of Triton X-100-treated whole cells of an oral treponeme, Treponema sp. strain E-21, revealed that six cytoplasmic fibrils (CFs) helically wound as a bundle in the cytoplasm. The CFs were isolated and purified by disruption and solubilization of the cells followed by CsCl density gradient centrifugation. The purified CF preparation contained mostly fibrils of about 9 nm in width and very small amounts of thinner strands of about 3 nm in diameter. The CFs were apparently seen to be a tubular structure, but the isolated CFs had narrowed sites of about 4-5 nm in width lacking lumen-like images, possibly representing twisted sites. Thus, the CF did not seem to be a tubular structure. The purified CFs were composed of one major 82 kDa protein and a few minor proteins. The CFs were destructed by treatment with proteases, 8 M urea or 4 M guanidine hydrochloride. Very low tyrosine content (0.76 mol %) and lack of methionine were characteristic features for the 82 kDa protein. The CF preparations from the other five treponemes including Treponema phagedenis and T. denticola also had 82 kDa proteins as a major component, and the 82 kDa proteins of all of the treponemes had a common antigen when examined by using antiserum against the 82 kDa protein from Treponema sp. strain E-21. Furthermore, the 82 kDa protein was demonstrated to be a principal component of the CFs of all the treponemes by immunoelectron microscopy.

Amino Acids↗
PubMed1989

Effect of vitamin B12 deficiency on S-adenosylmethionine metabolism in rats.

The effect of vitamin B12 (B12) deficiency on the levels of S-adenosylmethionine (SAM) in tissues and the activities of hepatic methionine synthase, methionine adenosyltransferase and glycine N-methyltransferase were investigated. The striking depression of methionine synthase activity was observed in all rats fed the B12-deficient diets with or without methionine supplementation for 150 days. The SAM level in liver was decreased by B12 deficiency. However, brain SAM level was not affected. The activities of hepatic methionine adenosyltransferase isozymes, alpha-form and beta-form, were decreased by B12 deficiency. Hepatic glycine N-methyltransferase activity in rats fed the low methionine-B12-deficient diet showed a tendency to lower, although the change the activity was not statistically significant, compared with B12-supplemented rats. It is proposed that the fall in the activity of hepatic methionine adenosyltransferase may be one of the causes of the decreased hepatic SAM level in B12-deficient rats.

5-Methyltetrahydrofolate-Homocysteine S-Methyltran↗
PubMed1989

Effect of vitamin B12-deficiency on the activity of hepatic cystathionine beta-synthase in rats.

The effect of vitamin B12(B12)-deficiency on the activities of hepatic methionine synthase, homocysteine methyltransferase, and cystathionine beta-synthase was investigated in rats. The rats bred from B12-deficient dams were fed the B12-deficient diets for 150 days after weaning. Growth retardation of the B12-deficient rats was already observed on day 30 and continued through 150 days. But dietary supplementation of 0.5% DL-methionine slightly improved the growth retardation. Urinary excretion of methylmalonic acid increased to about 15 mg/mg creatinine and hepatic B12 concentration declined to about 2 ng/g liver after a 150-day feeding of the B12-deficient diets. Hepatic methionine synthase activity in rats fed the B12-deficient diets supplemented with or without methionine decreased to about 5% of B12-supplemented controls. Hepatic betaine-homocysteine methyltransferase activity showed no significant change caused by B12-deficiency. Hepatic cystathionine beta-synthase activity in rats fed the B12-deficient diets supplemented with or without methionine decreased to about 61% and 27% of their B12-supplemented controls, respectively, but the decrease was partially improved by methionine supplementation. In conclusion, the rats bred from B12-deficient dams showed a severe B12-deficiency after a 150-day feeding of the B12-deficient diets. The decrease of hepatic cystathionine beta-synthase activity was supposed to be due to the adaptation by the defect of methionine resynthesis.

5-Methyltetrahydrofolate-Homocysteine S-Methyltran↗