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Biomedical subjects

K Masumoto

Publications and source records attributed to K Masumoto.

At least 55 records · Page 3Linked to original sources
PubMed1996

Permeability, morphologic and temperature changes of canal dentine walls induced by Nd: YAG, CO2 and argon lasers.

The permeability, temperature and morphologic changes of the wall of the root canal induced by Nd:YAG, CO2 and argon lasers were studied. The changes were evaluated according to the presence or absence of a smear layer. Root canals of 140 human single-rooted teeth were enlarged using a step-back technique. Permeability was evaluated by the extent of methylene blue dye penetration into the tubules. Temperature changes were measured using a thermovision system, and morphological changes were evaluated by scanning electron microscopy. Laser energy was delivered into the canal by means of a flexible optical fibre or metal tip. There were statistically significant differences in permeability between lased groups with and without a smear layer in the cervical third of the root canal following lasing. In the middle third of the root canal, all three laser types induced permeability increases in groups with a smear layer. In the apical third, statistically significantly decreases in permeability were observed among CO2 laser and Nd:YAG compared with control group (P < 0.01). Rises in temperature ranged from a minimum of +10.1 degrees C (CO2 laser) to a maximum of +54.8 degrees C (argon laser). All three laser devices appeared capable of producing a glazed-like surface and craters.

Analysis of Variance↗
PubMed1995

[Studies of novel 1,4-dihydropyridine Ca antagonist CS-905. I. Measurement of partition coefficient (log P) by high performance liquid chromatography (HPLC)].

A new 1,4-dihydropyridine derivative, CS-905, currently under development as a Ca antagonist, showed a gradual onset and long duration in its antihypertensive effect upon single oral administration. The partition coefficient for CS-905 was measured along with 11 known dihydropyridine Ca antagonists by the HPLC method to clarify its mode of action. The log PHPLC for CS-905 was, 5.18, almost the same as that of manidipine and this value is the highest among the measured drugs. Its pharmacokinetic profile in SHR was also discussed.

Animals↗
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↗
PubMed1988

Harderian gland dependency of immunoglobulin A production in the lacrimal fluid of chicken.

Involvement of the Harderian gland (HG) in the production of lacrimal immunoglobulin (especially IgA) was investigated. The lacrimal concentration of each immunoglobulin class was not affected by surgical bursectomy but was reduced by cyclophosphamide (CY) and testosterone (TP) treatments. Surgical removal of the Harderian gland caused a remarkable reduction of both the lacrimal concentration of each immunoglobulin class and the specific antibody titre, and and IgA was almost undetectable. The lacrimal concentration of each immunoglobulin class, as well as the specific antibody titre, was not affected by surgical removal of the Lacrimal gland (LG). The route of antigen administration produced no difference in the class of lacrimal immunoglobulin produced. The results indicate that the production of immunoglobulin in chicken tears may be dependent on the HG and that lacrimal immunoglobulin may be synthesized and secreted locally in the HG. Lymphocytes of the HG are of bursa of Fabricius origin and are seeded into the HG prior to hatching and its lymphocytes do not appear to be involved in systemic immunity.

Aging↗
PubMed1986

Simultaneous determination of codeine and chlorpheniramine in human plasma by capillary column gas chromatography.

A specific and highly sensitive capillary column gas chromatographic method was developed for the simultaneous determination of codeine and chlorpheniramine in human plasma. The method involves a solvent extraction and analysis by capillary column gas chromatography on a cross-linked 50% phenylmethyl silicone fused-silica capillary column with flame thermionic detection. A 10% solution of n-butanol in toluene was used as extraction medium and pyrilamine was used as internal standard. Reproducibility, linearity of calibration curves and specificity were all satisfactory with both drugs. The plasma concentration of codeine and chlorpheniramine could be measured at levels down to 0.9 ng/ml as codeine phosphate and 0.4 ng/ml as chlorpheniramine maleate, respectively. The method was applied to plasma samples from normal volunteers, and was confirmed to be adequate for biopharmaceutical and pharmacokinetic studies.

Adult↗
PubMed1981

Hexosamine metabolism during spherule formation in Physarum polycephalum.

Hexosamine metabolism in relation to the spherule-wall synthesis in Physarum polycephalum was studied by the incorporation of labeled sugar into the wall and intermediary compounds in the biosynthesis of wall polysaccharide. The incorporation of [14C]galactosamine into the wall material occurred after a lag period of about 10 h in an induction medium. Nucleotides and sugar phosphates in the acid-soluble fraction of spherulating plasmodia were analyzed by column chromatography on Dowex 1-X8 (formate). The primary labeled products formed in the spherulating plasmodia after incubation with [14C]galactosamine were galactosamine 1-phosphate, UDP-galactosamine, N-acetylhexosamine 6-phosphate and UDP-N-acetylhexosamine. Spherulation was insensitive to polyoxin D, while it was completely blocked by cycloheximide. The activity of galactokinase and galactose-1-phosphate uridyltransferase increased 4--5-fold during the spherulation.

Anti-Bacterial Agents↗
PubMedDate not supplied

The effect of a valine-rich diet on intestinal adaptation to massive small bowel resection in the rat.

BACKGROUND/PURPOSE: Recently, valine, which is one of the branched chain amino acids, has been reported to enhance liver regeneration after hepatectomy in the rat. The aim of this study was to investigate the effect of enteral valine supplementation on intestinal adaptation. MATERIALS/METHODS: Seven-week-old male Lewis rats underwent a 90% small bowel resection. The rats were randomly divided into two groups: group V (valine-rich diet) and group S (standard rat chow), according to the diet. The rats were sacrificed at the operation day and on postoperative days (POD) 7, 14, 30, and 60. The metrics were body weight (BW), blood amino acids, urine organic acids, and morphology of the residual small intestine. RESULTS: The BW and the intestinal wet weight, jejunal crypt depth, and proliferating cell nuclear antigen-positive cells in group V at POD 7 were significantly higher than those values in group S, while those in group V at POD 30 and 60 were smaller than those in group S. The urine methylmalonic acid (MMA) level in group V at POD 30 and 60 was much higher than in group S. CONCLUSION: Valine enhanced intestinal adaptation after massive small bowel resection in the acute phase. However, the long-term supplementation disturbed intestinal adaptation, which might be due to the high production of MMA.

Animals↗
PubMedDate not supplied

Outcome of fetal cystic hygroma and experience of intrauterine treatment.

OBJECTIVE: To review our cases of fetal cystic hygroma and to examine the prognostic factors with the goal of establishing criteria for the intrauterine treatment for cystic hygroma. PATIENTS AND METHODS: Thirty-one cases of fetal cystic hygroma were managed by us from January 1988 to December 1997, and 21 cases were available for analysis. Three prognostic factors, namely chromosomal abnormality, structural anomaly and hydrops fetalis, were evaluated. We treated 2 cases of cystic hygroma associated with hydrops fetalis in utero using OK-432 injection under ultrasound guidance. RESULTS: The fetuses without any of the prognostic factors listed above showed a good prognosis throughout the fetal and neonatal periods. However, in this group, 2 infants with large tumors died of hemorrhage from the tumor at 6 months and 3 years of age, respectively. Cases with hydrops fetalis without chromosomal abnormalities or structural anomalies (5 cases) resulted in either intrauterine fetal death (IUFD, 2 cases) or early perinatal neonatal death (early PND, 3 cases). The cause of early PND was circulatory failure. Most of the hydrops cases with either a chromosomal abnormality or structural anomaly resulted in IUFD before 22 weeks of gestation. The size of the cyst decreased in 1 of 2 cases treated in utero. CONCLUSIONS: The fetal cases of cystic hygroma showing hydrops fetalis without chromosomal abnormalities or structural anomalies are considered to be possible candidates for intrauterine therapy. Those with very large cystic hygroma without any of the three prognostic factors are also thought to be candidates for fetal treatment. Based on our clinical experience, sclerotherapy using OK-432 is considered to be a treatment option in selected cases with fetal cystic hygroma.

Chromosome Aberrations↗