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Biomedical subjects

K Shirai

Publications and source records attributed to K Shirai.

At least 19 recordsLinked to original sources
PubMed2002

Improved filler-matrix coupling in resin composites.

Ineffective silane coupling between filler and matrix within dental composites is prone to accelerated in vivo degradation. In this study, we examined to what degree a procedure involving chemical decontamination of filler prior to silanization could improve the filler-matrix bonding, and thus the physico-mechanical properties, of composites. X-ray photoelectron spectroscopy revealed that filler-matrix coupling largely depended upon siloxane bridge (Si-O-Si) formation between the silica surface and the silane molecule, rather than on intermolecular bonding between adjacent silane molecules. Pre-silanization decontamination based upon boiling silica in 0.05-5% sodium peroxodisulfate, followed by ultrasonic rinsing in acetone, most effectively decontaminated filler. Consequently, it significantly improved the bonding of silane molecules to silanol groups at the silica surface. Experimental composites produced following pre-silanization decontamination of filler revealed a diametral tensile strength that was resistant to degradation by thermocycling.

Composite Resins↗
PubMed2001

Effect of initial glucose concentration and inoculation level of lactic acid bacteria in shrimp waste ensilation.

Fermentation conditions and microorganisms were determined, based on acid production, glucose concentration as carbohydrate source. Inoculation levels to obtain a stable shrimp waste silage were also determined. Shrimp waste ensilation was an efficient method of preservation, allowing the recovery of chitin and another added-value products such as pigments, proteins and enzymes. From the various lactic acid bacteria tested, Lactobacillus pentosus and Lactobacillus sp. (B2) were the best lactic acid producers, although small quantities of acetic acid were detected in samples inoculated with Lactobacillus pentosus. Therefore B2 was chosen for the analysis of glucose consumption as well as for the determination of optimum inoculation levels. The best results were obtained at 10% (w/w wet basis) and 5% (v/w wet basis) respectively. Presence of starters and initial glucose concentration were critical factors in the fermentation of shrimp waste. High initial glucose and starter concentrations reduced the time and increased the amount of lactic acid produced. The fermentation pattern changed during ensilation from hetero to homofermentative. Shrimp waste ensilation prevented the growth of spoilage microorganisms keeping their microbial counts steady and pH values within the acid region.

Journal Article↗
PubMed2001

Expression of transcription factor AP-1 in rat lens epithelial cells during wound repair.

We examined the spatial and temporal expression patterns of proteins and mRNAs of the components of transcription factor activator protein 1 (AP-1) to examine the activation pattern of lens epithelial cells during lens wound repair following an anterior capsular injury. One eye of adult Wistar rats (n = 106) were used. After making a lens anterior capsule incision with a hypodermic needle, the affected eye was enucleated 0 and 30 min, 1, 3, 5, 8, 10, 15, 20, 24 hr after injury. Forty six globes were processed for in situ hybridization with oligonucleotide probes for c-fos, fosB, c-jun, junB and junD mRNAs, and 60 globes were immunohistochemically analysed using anti-c-Fos and anti-c-Jun antibodies. Normal lens epithelial cells expressed mRNA signals for junD, but not for c-fos, fosB, c-jun, and junB. mRNAs for c-fos, fosB, c-jun, and junB were detected in the whole lens epithelium from the vicinity to the wound to the equator from 30 min to 8 hr post-injury with their peaks after 30 min to 1 hr, but were no longer detected at 10 hr or later. Expression of c-fos mRNA in the equatorial lens cells was more marked than that of c-jun mRNA. Immunohistochemistry showed that c-Fos protein was expressed in the lens epithelial cells in both the anterior and equatorial regions of the injured lens from 1 to 10 hr after injury, and was no longer detected at 12 hr. C-Jun protein was detected only in the equatorial lens cells from 1 to 5 hr after injury, and was no longer detected at 8 hr. Lens epithelial cells except those in the equatorial region did not express c-Jun protein. These findings indicate that transcriptional activation of lens epithelial cells is initiated in the very early phase after the lens injury, i.e. 30 min post-injury, suggesting that AP-1 may play important roles in regulating lens cell behavior during lens wound repair in rats.

Animals↗
PubMed2001

Accumulation of latent transforming growth factor-beta binding protein-1 and TGF beta 1 in extracellular matrix of filtering bleb and of cultured human subconjunctival fibroblasts.

PURPOSE: To examine immunohistochemically whether extracellular matrix (ECM) of the filtering bleb and of cultured human subconjunctival fibroblasts contains latent TGF beta binding protein-1 (LTBP-1) and TGF beta. METHODS: An enucleated human eye that had undergone trabeculectomy and cultured human subconjunctival fibroblasts were processed for light microscopic immunohistochemistry. Antibodies against LTBP-1, collagen types, fibrillin-1 and TGF beta s were used. TGF beta 1 was located by detecting beta 1-latency associated peptide (LAP). RESULTS: LTBP-1, beta 1-LAP and fibrillin-1 were all located in the subepithelial ECM as well as in the basal epithelial cells of the conjunctiva over the filtering bleb. TGF beta 2 and beta 3 were immunolocated to epithelium and/or fibroblasts/keratocytes. ECM deposited in confluent fibroblast cultures was positive for beta 1-LAP, LTBP-1 and fibrillin-1, whereas sparse cells were negative. CONCLUSIONS: LTBP-1, beta 1-LAP and fibrillin-1 are co-localized to the ECM of the filtering bleb and of cultured conjunctival fibroblasts. Both conjunctival epithelium and fibroblasts are considered to be the source of TGF beta in healing bleb. ECM secreted by in vivo and in vitro subconjunctival fibroblasts may works as a scavenger or repository of TGF beta.

Carrier Proteins↗
PubMed2001

Alcohol consumption and severity of angiographically determined coronary artery disease in Japanese men and women.

The relation of alcohol consumption to the severity of coronary atherosclerosis was examined among 323 men and 220 women who underwent coronary arteriography. Severity of coronary atherosclerosis was assessed by the number of vessels obstructed > or =75% in diameter and Gensini's severity score. Alcohol consumption was divided into 5 categories in men (never, past, 1-24, 25-49, and > or =50 ml per day) and 3 categories in women (never, past, and current). Among men, odds ratios of severe stenosis (multiple-vessel disease or Gensini's score >15) decreased substantially and significantly in all current drinking categories but without dose-response effect. There was a weak, inverse association of current alcohol consumption with one-vessel disease, but not with moderate stenosis in terms of Gensini's score (< or =15). Past drinkers showed a fairly large, but statistically nonsignificant, decrease in the odds ratios of not only severe stenosis but also of moderate stenosis. Among women, current drinkers showed a small, statistically nonsignificant decrease in the risk of severe stenosis in terms of Gensini's score. These associations with alcohol use did not change after adjustment for known coronary risk factors. The present findings add to evidence that alcohol drinking confers protection against coronary atherosclerosis.

Adult↗
PubMed2001

Comparison of Scheimpflug images of posterior capsule opacification and histological findings in rabbits and humans.

PURPOSE: To compare the posterior capsule opacification in Scheimpflug photographic images produced by an electronic anterior eye segment analysis system with the histopathological findings in rabbits and humans. SETTING: Department of Ophthalmology, Wakayama Medical College, Japan. METHODS: Opacified posterior capsules were photographed using the EAS-1000 system (Nidek) and were then extracted during vitreous surgery for proliferative diabetic retinopathy or proliferative vitreoretinopathy in 2 patients. In rabbits, phacoemulsification and aspiration (PEA) with intraocular lens (IOL) implantation was performed. The IOL was implanted in the bag or in the sulcus. After intervals of healing, the posterior capsule was photographed with the EAS-1000 and the animals were then killed. In both clinical and experimental specimens, the posterior capsule was processed for light microscopic histology and immunohistochemistry. RESULTS: Opacified human capsules were well imaged by the EAS-1000. Histology showed that lens epithelial cells proliferated with and without an accumulation of extracellular matrix. Details such as rolling of the capsulotomy edge were seen well. Regenerated lens fibers of Soemmering's ring were seen as a mass within the capsule. In the rabbit model, Scheimpflug images accurately represented the capsules as they appeared histologically. CONCLUSION: The EAS-1000 system provided faithful, relatively high-resolution images that corresponded to the histologic findings in the posterior capsules after PEA-IOL surgery in humans and rabbits.

Aged↗
PubMed2001

Detection of porphyrin using a short peptide immobilized on a surface plasmon resonance sensor chip.

In this paper the development and feasibility of a novel detection system for a low molecular weight chemical, in which a peptide was utilized as a binding molecule, are described. Surface plasmon resonance (SPR) apparatus was used as a transducer. The porphyrin binding peptide, PSP2, was used as a model peptide ligand, while a porphyrin derivative, H(2)TMpyP, was used as a model low-molecular-weight chemical. PSP2 was covalently immobilized onto the SPR sensor chip and SPR measurement using the PSP2-immobilized chip for various concentrations of porphyrin was carried out. H(2)TMpyP was detectable in the range from 100 ng ml(-1) to 10 microg ml(-1) with a linear correlation and good precision and the PSP2-immobilized chip could be regenerated within 1 min after measurement in this system. From comparison of the detection manners of three porphyrin derivatives, the ability of a short peptide to discriminate between differences in molecular structure was demonstrated. Moreover, the self-assembled monolayer (SAM) of PSP2 was successfully prepared on the gold substrate and H(2)TMpyP could be detected using the PSP2-SAM chip.

Amino Acid Sequence↗
PubMed2001

Effect of transglutaminase on reconstruction and physicochemical properties of collagen gel from shark type I collagen.

The effects of microbial transglutaminase (MTGase) on type I collagen self-assembly and properties of reconstructed collagen fibrils from shark were investigated. Collagen self-assembly was accelerated with the addition of MTGase in dependence on that concentration. The relative amount of reconstructed collagen slightly decreased with MTGase. The diffusion coefficient of collagen gel was reduced by treatment with MTGase, and that suggested the reduction of mobility of the whole collagen network. At a high temperature, used to denature the collagen, MTGase-treated collagen gel remained as aggregates. By differential scanning calorimetry, the denaturation temperature of MTGase-treated collagen gel was about 2 degrees C higher than that of nontreated collagen gel. Treatment with MTGase yielded thermally stable cross-links in collagen molecules.

Animals↗
PubMed2001

Obesity, body fat distribution and coronary atherosclerosis among Japanese men and women.

OBJECTIVE: To investigate the relation of the obesity and body-fat distribution with angiographically defined coronary atherosclerosis. DESIGN: Cross-sectional study in a clinical setting. SUBJECTS: Three hundred and twenty men (median age, 59 y) and 212 women (median age, 67 y) who underwent coronary angiography for suspected or known coronary heart disease at 5 cardiology departments between September 1996 and August 1997. Patients with disease duration >1 y were excluded. MEASUREMENTS: The body mass index (BMI) and the waist to hip circumference ratio (WHR) were used as main exposure variables, and either the presence of significant coronary stenosis or the Gensini's score (> or =10 vs<10) as an outcome variable, in a sex-specific multiple logistic regression analysis controlling for age, hospital, and other coronary risk factors. RESULTS: Among male patients, BMI was progressively higher with an increasing number of vessels involved (P trend=0.05); the adjusted odds ratios for the presence of significant stenosis across quartiles of BMI were 1.0 (reference), 1.1, 1.9 and 2.5 (P trend=0.02), and the positive association was more pronounced for younger patients. Among females, however, such associations were not evident. Employing the Gensini's score as an outcome gave similar results. WHR was not significantly associated with either outcome regardless of sex. CONCLUSION: These results suggested that BMI was predictive of coronary stenosis among male patients, but not among female patients. Unlike most previous studies, this study failed to detect a positive association with WHR.

Adipose Tissue↗
PubMed2001

Clinical significance of preheparin serum lipoprotein lipase mass in coronary vasospasm.

The present study investigated the clinical significance of preheparin serum lipoprotein lipase (LPL) mass in coronary vasospasm by examining its relationship with the acetylcholine-induced coronary artery response in patients without angiographically demonstrable atherosclerotic coronary artery disease (CAD). The subjects were 39 men who had suspected CAD and who underwent coronary angiography. Coronary vasospasm was defined as a marked luminal narrowing or total occlusion provoked by the intracoronary administration of acetylcholine. Preheparin LPL mass was lower (p<0.05) in 25 subjects in whom vasospasm was induced by the acetylcholine provocation test than in the 14 subjects with a negative response. As regards preheparin LPL mass, the subjects with multiple vessel spasm had significantly low concentrations (p<0.05) compared with single vessel spasm, although serum lipid levels were not significantly different. Multiple regression analysis revealed only preheparin LPL mass had a significant absolute t-value (2.016) among the coronary risk factors. Low preheparin LPL mass is interpreted as reflecting an impaired acetylcholine-induced coronary relaxation in coronary vasospasm and preheparin LPL mass may be useful as a marker of early stage coronary atherosclerosis that is not detectable by angiography.

Acetylcholine↗
PubMed2001

Role of hypertension, dyslipidemia and diabetes mellitus in the development of coronary atherosclerosis in Japan.

The present study evaluated the effect of hypertension (HT), dyslipidemia and diabetes mellitus (DM) on the development of coronary atherosclerosis in the Japanese population, using a cross-sectional study of 433 patients (254 men and 179 women) aged 30 years or older who underwent coronary angiography for suspected or known coronary heart disease angina at 5 cardiology departments in the Fukuoka area between September 1996 and August 1997. Patients with a disease duration of 6 months or more were excluded. The main outcome measure was angiographically defined coronary artery stenosis and was found to a significant degree in 146 patients (33.7%). HT, DM, low levels of high-density lipoprotein cholesterol (HDL-C) and hypertriglyceridemia remained as significant coronary artery disease (CAD) risk factors even after controlling for age, sex, hospital, smoking, alcohol use, body mass index and leisure time physical activity. However, hypercholesterolemia was not a significant risk factor after adjusting for these variables. After controlling for these variables, DM, low HDL-C and hypertriglyceridemia were significant CAD risk factors for men, but only DM was a significant CAD risk factor in women. These results indicate that in Japan DM, low HDL-C and hypertriglyceridemia may be more important CAD risk factors than hypercholesterolemia.

Adult↗
PubMed2001

Improvement of shark type I collagen with microbial transglutaminase in urea.

In the presence of urea, type I collagen could form a gel with crosslinks with microbial transglutaminase (MTGase). Collagen self-assembly was accelerated with the addition of MTGase. The proportion of reconstructed collagen fibrils was raised with the addition of MTGase. MTGase-treated collagen gel remained gelled at high temperatures at which collagen denatured. By treatment with MTGase, collagen could form the gel under impossible condition to collagen self-assembly, and that denaturation temperature was raised.

Animals↗
PubMed2001

[The effect of celiprolol hydrochloride for lipid metabolism--especially for the low density lipoprotein particle size].

Recently, much attention has been paid to small sized low density lipoprotein (LDL) as a risk factor for ischemic heart disease. We investigated the effect of celiprolol hydrochloride (CH), which is a beta 1 selective beta-blocker with high intrinsic sympathomimetic activity (ISA), on the LDL particle size. We treated 41 hypertensive patients with CH and studied the change in LDL particle size according to the score of fast beta lipoprotein and LDL relative mobility value (LDL-Rm) measured by lipoprotein polyacrylamide gel disc electrophoresis (PAGE). We also studied changes in blood pressure, total cholesterol (TC), trygiyceride (TG), high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C) and midband on PAGE. Systolic and dyastolic blood pressure and pulse significantly decreased during treatment. TC levels were significantly decreased at 8 weeks in all subjects and at 4, 8 and 12 weeks in patients with a TC value of over 220 mg/dl. TG levels were significantly decreased at 4 and 8 weeks in patients with initial levels of over 150 mg/dl, and significantly increased at 4 and 8 weeks in those with initial levels of under 150 mg/dl of TG. HDL-C levels did not significantly change during treatment. LDL-C levels were significantly decreased at 4, 8 and 12 weeks in patients with initial levels of over 150 mg/dl. Apo AI, AII, B, CII, CIII and E levels did not significantly change during treatment. Fast beta lipoprotein scores did not significantly change overall during treatment, but were significantly decreased at 4 and 8 weeks in patients initial TG levels of over 150 mg/dl and at 4 and 12 weeks in those with initial levels of over 220 mg/dl of TC. LDL-Rm scores did not significantly change during treatment. Midband scores were significantly reduced overall at 8 weeks, and after 4 and 8 weeks in patients with initial TG levels of over 150 mg/dl and at 4, 8 and 12 weeks in those with initial TC levels of over 220 mg/dl. These results indicated that CH did not change LDL particle size. It was suggested that CH might be a beneficial beta-blocker from the standpoint of prevention for atherosclerosis.

Aged↗
PubMed2001

Effect of temocapril hydrochloride on serum lipid levels in patients with hypertensive type 2 diabetes mellitus.

The effect of angiotensin converting enzyme inhibitor, temocapril hydrochloride on the serum lipoproteins, and especially on the size of low density lipoproteins (LDL) of hypertensive diabetic patients, were studied. Temocapril hydrochloride (5 mg/day) was administered to 32 hypertensive type 2 diabetes patients for 16 weeks. During treatment, systolic and diastolic blood pressures decreased significantly from 162/95 mmHg to 138/76 mmHg at 16 weeks (p<0.001), and serum levels of total cholesterol (TC) and low density lipoprotein cholesterol (LDL-C) showed significant reduction, but those of HbA1c, triglycerides (TG) and high density lipoprotein cholesterol (HDL-C) showed no significant changes. LDL particle size evaluated by polyacrylamide gel disc electrophoresis was normalized from small size. It is concluded that temocapril hydrochloride favorably affects the serum lipoprotein metabolism of hypertensive type 2 dependent diabetes mellitus patients.

Antihypertensive Agents↗
PubMed2001

[Evaluation of obesity and diagnostic criteria of obesity as a disease for Japanese].

Obesity causes many undesirable health disorders such as diabetes mellitus, hyperlipidemia, hypertension and so on. Recently, those life style-affecting diseases is increasing, especially the increment of diabetes mellitus is prominent. In 2000, Japan obesity society issued the new standard of the evaluation of obesity and new diagnostic criteria of obesity as a disease for Japanese. According to this issue, obesity was evaluated by body mass index(BMI). And, 18.5 < BMI < 25 is normal, 25 < BMI < 30 is obese 1, 30 < BMI < 35 is obese 2, 35 < BMI < 40 is obese 3, and 40 < is obese 4. Obesity as a disease is defined by two cases. The first category is composed of two items; one is BMI > 25, and the other is having one disease worsen by obesity, such as diabetes mellitus, hyperlipidemia, hypertension, hyperuricemia, coronary heart disease, cerebral infarction, sleep apnea syndrome, fatty liver, deformative arthritis. The second category is the visceral type of obesity with BMI > 25, which was diagnosed by west size, over 85 cm for men, and over 90 cm for women, and by visceral fat area over 100 cm2 in abdominal CT.

Asian People↗
PubMed2001

[HMG-CoA synthase].

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Coenzyme A Ligases↗