Biomedical subjects

T Yanagawa

Publications and source records attributed to T Yanagawa.

206 records · Page 12Linked to original sources

PubMedDate not supplied

Adaptation of a resin composite in vivo.

OBJECTIVE: The adaptation of experimental dentine bonding systems has been evaluated in vivo. METHODS: A cylindrical cavity which extended into dentine was prepared in the facial surface of vital teeth that were to be extracted for orthodontic reasons. The preparations were restored with a commercial light-activated resin composite that was mediated by experimental dentine bonding systems. The restored teeth were extracted as soon as possible following polymerization of the composite. The marginal and internal adaptation of the resin composite restoration was observed under a light microscope in both horizontal and longitudinal sections of the teeth immediately after extraction. RESULTS: Of the experimental dentine bonding systems investigated, those including a primer of glyceryl methacrylate showed complete adaptation whereas those with primers of 2-HEMA showed a contraction gap in three out of 10 specimens.

Bisphenol A-Glycidyl Methacrylate↗

PubMedDate not supplied

Aqueous vascular endothelial growth factor and basic fibroblast growth factor decrease during regression of rabbit pupillary membrane.

We studied the roles of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) in the aqueous during regression of the pupillary membrane in rabbits. Aqueous samples were obtained using a 30-gauge needle passed through the limbus in newborn rabbits. The VEGF and bFGF levels were measured by a quantitative sandwich enzyme-linked immunosorbent assay. The aqueous VEGF levels at 60 days of age (29.0-351.9 with a median of 190.5 pg/mL) decreased significantly compared with those at 12 and 20 days of age (356.7-1148.3 with a median of 752.5 pg/mL at 12 days of age and 193.5-657.7 with a median of 425.6 pg/mL at 20 days of age, Mann-Whitney U Test, P < 0.0001 and P = 0.002, respectively). The aqueous bFGF levels at 60 days of age (0.0-126.2 with a median of 63.1 pg/mL) decreased significantly compared with those at 12 days of age (33.4-301.3 with a median of 167.4 pg/mL, P < 0.0001). Light microscopically, the pupillary membrane at 12 days of age was rich with capillaries that were subsequently closed at 20 days of age, and the membrane itself disappeared at 60 days of age. The aqueous VEGF and bFGF levels decreased in the process of regression of the pupillary membrane, suggesting that VEGF or bFGF played a role in eye development such as maintenance of the pupillary membrane.

Animals↗

PubMedDate not supplied

TIMP-1 and TIMP-2 levels in vitreous and subretinal fluid.

To understand the role of tissue inhibitors of metalloproteinase-1 and -2 (TIMP-1 and TIMP-2) in intraocular diseases, levels of TIMP-1 and TIMP-2 were measured by enzyme immunoassay in 47 patients with various ocular diseases: in subretinal fluid of 7 patients with rhegmatogenous retinal detachment and in vitreous of 12 patients with proliferative diabetic retinopathy, 4 with proliferative vitreoretinopathy, 2 with vitreous hemorrhage due to branch retinal vein occlusion, 12 with idiopathic macular hole, 3 with retinal detachment due to high-myopic macular hole, 4 with macular epiretinal membrane, and 3 with choroidal neovascular membrane due to age-related macular degeneration. TIMP-1 levels were significantly higher in subretinal fluid than in vitreous fluid with any diseases (P < 0.0001, Mann-Whitney U test). TIMP-1 levels in vitreous fluid of the eyes with proliferative diabetic retinopathy and proliferative vitreoretinopathy were higher than those in vitreous with other diseases (P < 0.0001). In contrast, TIMP-2 levels were not elevated in the subretinal fluid and vitreous. TIMP-1, but not TIMP-2, was secreted into the subretinal space in rhegmatogenous retinal detachment, and also into the vitreous in eyes with proliferative disease, suggesting that TIMP-1 would play a specific role in the process of these diseases.

Biomarkers↗

PubMedDate not supplied

Postnatal exposure to chlorinated dioxins and related chemicals on lymphocyte subsets in Japanese breast-fed infants.

Effects of postnatal exposure to polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and coplanar polychlorinated biphenyls (Co-PCBs) on lymphocyte subpopulations were investigated in the peripheral blood of 36 breast-fed Japanese babies. As a result, estimated total intakes of these chemicals in toxic equivalent quantity (TEQ) converted into 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) equivalents from the breast milk positively and negatively correlated with the respective percentages of CD4+ and CD8+ lymphocytes in the blood of breast-fed babies. Consequently, the ratios of CD4+ to CD8+ T cells showed significant increasing tendency with the estimated total TEQ intakes. Therefore, our study suggests that exposure to background levels of the highly toxic organochlorine compounds through the breast milk influences the human neonatal immune system.

Adult↗

PubMedDate not supplied

Postnatal exposure to chlorinated dioxins and related chemicals on thyroid hormone status in Japanese breast-fed infants.

Effects of postnatal exposure to polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and coplanar polychlorinated biphenyls (Co-PCBs) on thyroid hormone status were studied in the peripheral blood of 36 breast-fed Japanese infants. Estimated total intakes of these chemicals in toxic equivalent quantity (TEQ) converted into 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) from the breast milk significantly and negatively correlated with the levels of triiodothyronine (T3) and thyroxine (T4) in the blood of breast-fed babies. Therefore, exposure to background levels of the highly toxic organochlorine chemicals through the breast milk may cause some effects on thyroid hormone status in Japanese infants.

Adult↗

PubMedDate not supplied

Presence of dopamine DA-1 receptors in human decidua.

To evaluate the role of dopamine in human parturition, we studied the presence of dopamine receptors in human decidua obtained immediately after delivery, using a radiolabelled receptor assay. [3H]SCH23390, a dopamine DA-1 receptor ligand was used to identify and characterize the DA-1 receptor. Scatchard analysis of our saturation experiments revealed one class of high-affinity binding sites. The equilibrium dissociation constant (Kd) for binding of [3H]SCH23390 to decidual DA-1 receptors was 1.87 +/- 0.16 nM (mean +/- s.d. n = 3) at 30 degrees C. The maximum binding capacity (Bmax) was 79.0 +/- 15.4 fmol/mg protein at 30 degrees C. The specificity of DA-1 receptor binding was inhibited by SCH23390 (a DA-1 antagonist), SKF38393 (a DA-1 agonist) and dopamine with the inhibitory constants (Ki) of 5.82 +/- 2.27 nM (mean +/- s.d., n = 3), 45.6 +/- 30.5 nM (mean +/- s.d. n = 3) and 2.86 +/- 1.02 microM (mean +/- s.d., n = 3) respectively. However, (+/-)-sulpiride (a DA-2 antagonist) and (-)-propranolol (a beta-adrenergic antagonist) were without effect. The specific binding of [3H]spiperone (a DA-2 receptor ligand) was not detected. We previously reported that in vitro the human decidual tissues produce significant amounts of prostaglandins in the presence of dopamine. We postulate that dopamine regulates the production of prostaglandin in human decidua via DA-1 receptors.

Benzazepines↗

PubMedDate not supplied

Acute transverse myelitis caused by Coxsackie virus B5 infection.

A 6-year-old boy developed symptoms of rapidly progressive paraplegia, associated with bowel and urinary dysfunction, but without sensory loss. Magnetic resonance imaging (MRI) examination showed diffuse swelling of the lower spinal cord on T1-weighted images. Based on the clinical presentation and MRI findings, a diagnosis of acute transverse myelitis was made. The serum titer of neutralizing antibody against Coxsackie virus B5 rose from 1/4 on admission to 1/256 1 month later and Coxsackie virus B5 was isolated from stool samples. This case serves as a reminder that acute transverse myelitis can be a rare clinical manifestation of Coxsackie virus B5 infection.

Antibodies, Viral↗

PubMedDate not supplied

Advantage of in vivo chemosensitivity assay to detect vincristine-resistance in a human epidermoid carcinoma xenograft.

We examined both in vitro and in vivo chemosensitivity of the human epidermoid carcinoma xenograft xeKB3-1-R which shows overexpression of the multidrug resistance gene (MDR1). XeKB3-1-R was sensitive to vincristine (VCR, 6%) and doxorubicin (DOX, 9%) in the adhesive tumor cell culture system in vitro. However, this xenograft showed decreased sensitivity to VCR (65%) and DOX (42%) in an in vivo chemosensitivity assay. The in vivo resistance of xeKB3-1-R to both VCR and DOX was reversed by coadministration of cyclosporin A (VCR 22%, DOX 11%). The xenograft xeKB3-1-R expressed significantly higher levels of MDR1 than xeKB3-1. The results confirmed that multidrug resistance in xeKB3-1-R was related to enhanced MDR1 expression in vivo. The observed discrepancies between in vitro and in vivo chemosensitivities suggest that the in vivo sensitivity assay more accurately reflects drug resistance as a result of low-level MDR1 overexpression in solid tumors.

Animals↗