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Biomedical subjects

Y Hara

Publications and source records attributed to Y Hara.

874 records · Page 49Linked to original sources
PubMedDate not supplied

Retina tomography after vitrectomy for macular edema of central retinal vein occlusion.

PURPOSE AND OBJECTIVE: To report retina tomography after vitrectomy for macular edema in central retinal vein occlusion (CRVO). PATIENTS AND METHODS: Five patients with macular edema caused by CRVO were examined using optical coherence tomography (OCT) through their clinical courses. RESULTS: The retinal thickness through the fixation was reduced in all 5 eyes. Preoperatively, the retina thickness at the foveola was more than 500 microm in three eyes and more than 1000 microm in 2 eyes. The retina thickness was reduced to 311+80 microm within two weeks on average. Visual acuity was improved by two or more lines in 3 of 5 eyes. CONCLUSION: Vitrectomy is worthy of consideration when macular edemas are prolonged in patients of CRVO. OCT is a useful instrument for management and treatment of macular edema.

Aged↗
PubMedDate not supplied

Electrophysiological and clinical assessment of a simple wrist-hand splint for patients with chronic spastic hemiparesis secondary to stroke.

PURPOSE: The aim of this study is to assess the effect of a simple wrist-hand splint, made of mesh materials, on the spastic paretic hand. METHODS: The participants were 15 patients with hemiparetic stroke. Time from stroke onset was over 120 days. We assessed integrated EMG of flexor digitorum sublimus (FDS), extensor indicis proprius (EIP), flexor carpi radialis (FCR), extensor carpi radialis (ECR), brachioradialis (BR) and triceps brachii (Tri) during active finger extension and shoulder flexion, without and with the wrist-hand splint. H reflexes and M waves were obtained on FCR by stimulating the median nerve, and H/M ratio was calculated. In another 5 patients who used the splint for 8 weeks, its long-term effects were assessed with clinical measures (active range of motion and muscle tone). RESULTS: With the splint, muscle activities of FCR and BR were reduced during shoulder flexion, and those of FDS, FCR and BR decreased during finger Attaching the splint also reduced the H/M ratio of FCR. In five patients who had worn the wrist-hand splint during daytime for 8 weeks, significant increase in the active range of shoulder flexion and finger extension and decrease in muscle tone were demonstrated. The splint reduced co-activation of antagonists not only in wrist but also in finger and elbow muscles. CONCLUSION: It is suggested that the wrist-hand splint is beneficial to improve upper limb motor function in patients with spastic hemiparesis.

Chronic Disease↗
PubMedDate not supplied

Stimulation by epigallocatechin gallate of interleukin-1 production by human peripheral blood mononuclear cells.

(-) Epigallocatechin gallate (EGCg) potently stimulated the production of interleukin-1 (IL-1) and tumor necrosis factor by human peripheral blood mononuclear cells. The intracellular amounts of IL-1 beta and especially IL-1 alpha induced by EGCg, were significantly higher than their extracellular counterparts. ECCg stimulated the production of adherent cells, with IL-1 producing capacity (per cell basis) that was significantly higher than nonadherent cells. Although IL-1 alpha mRNA synthesis (assessed by Reverse Transcriptase-Polymerase Chain Reaction) was slightly enhanced, IL-1 beta mRNA synthesis was not significantly enhanced by EGCg treatment. Lipopolysaccharide (LPS) also stimulated the production of IL-1 alpha and IL-1 beta production, but failed to induce the adherent cells. These data suggest that EGCg and LPS stimulate mononuclear cells by different mechanisms.

Antineoplastic Agents↗
PubMedDate not supplied

Design concept and construction of a hybrid lamellar keratoprosthesis.

A novel hybrid lamellar keratoprosthesis composed of epithelium and stroma was developed. Artificial extracellular matrices were constituted of photocrosslinkable copolymers of N,N-dimethylacrylamide and 2-(7-coumaroxy)ethyl methacrylate; a copolymer with a high content of coumarin (A) was used as a basement membrane (BM) for the epithelium, and a copolymer with a low content (B) was used for entrapment of keratocytes. The lamellar keratoprosthesis was constructed as follows: First, a viscous buffer solution containing water-soluble copolymer (B), collagen, and keratocytes derived from rabbit was prepared. Then, a cast film of copolymer (A) was tightly placed onto the mixed solution. Ultraviolet light irradiation leading to intermolecular dimerization of coumarin groups resulted in the formation of a transparent keratocyte-entrapped hydrogel that was layered with an artificial BM. Epithelial cells were seeded on the BM. Further culturing produced the lamellar keratoprosthesis, within which both kinds of cells proliferated well. The preliminary study on two week implantation of the lamellar keratoprosthesis in rabbits provided quite promising results; adverse tissue reactions, such as corneal opacity and neovascularization, were not observed.

Animals↗
PubMedDate not supplied

Inhibition of xanthine oxidase by catechins from tea (Camellia sinensis).

Some epidemiological studies have associated tea drinking with several health benefits, while other such studies have been inconclusive. The liver enzyme, xanthine oxidase (XO) produces uric acid and reactive oxygen species (ROS) during the catabolism of purines. Excess of the former can lead to gout and of the latter to increased oxidative stress, mutagenesis and possibly cancer. Polyphenols are antioxidants, and it has been suggested that they can reduce oxidative stress by their antioxidant properties. We report here on the inhibition of XO by five tea catechins and two flavones. The Ki values (microM) and types of inhibition were catechin (C) (Ki = 303.95, uncompetitive), epicatechin (EC) (Ki = 20.48, mixed), epigallocatechin (EGC) (Ki = 10.66, mixed), epicatechin gallate (ECg) (Ki = 2.86, mixed) and epigallocatechin gallate (EGCg) (Ki = 0.76, competitive). The Ki of EGCg was similar to that of allopurinol (Ki = 0.30, mixed), the drug of choice for inhibition of XO in gout patients. Thus, tea catechins may act at.an earlier stage than has previously been suspected, by inhibiting ROS production, rather than only neutralizing the already formed ROS. This suggests a new mechanism whereby tea drinking may prevent oxidative stress related diseases, e.g. atherosclerosis and cancer.

Antineoplastic Agents↗
PubMedDate not supplied

Effects of tamoxifen on mammary tumors and bone in 7,12-dimethylbenz-(a)anthracene-treated rats.

We investigated the effects of tamoxifen on the growth of 7,12-dimethylbenz(a)anthracene induced rat mammary tumors, the activity of thymidylate synthetase and thymidine kinase (key enzymes involved in de novo and salvage pathways for pyrimidine nucleotide synthesis), and also their gene expression. The effects on immunohistochemistry using bromodeoxyuridine in the tumors and bone mineral density of the femur in rats were also studied. Chronic administration of tamoxifen markedly reduced the expression of thymidylate synthetase mRNA, followed by a reduction in enzyme activity and S-phase cells in the mammary tumors, and significantly enhanced the bone mineral density. Tamoxifen not only attenuated bone loss in aging but also enhanced bone volume in mammary tumor-bearing rats in which tumor growth was suppressed via both the de novo and salvage pathways for pyrimidine nucleotide synthesis.

9,10-Dimethyl-1,2-benzanthracene↗
PubMedDate not supplied

Muscle fiber conduction velocity (MFCV) after fatigue in elderly subjects.

The changes in muscle fiber conduction velocity (MFCV) and median frequency (MDF) during and after muscle fatigue were investigated in 9 younger (mean age: 29.3) and 7 elderly (mean age: 72.0) healthy subjects to determine if age has any effect on them. The surface EMG of the abductor digiti minimi muscle was examined at 50% of maximal voluntary contraction (MVC) during a prefatigue session. The subjects were instructed to continue applying maximal force until the force declined to 50% MVC. EMG signals were measured during brief subsequent contractions at 50% MVC until 60 minutes after fatigue as a postfatigue session. The decrement in MFCV and MDF at 50% MVC before and after fatigue was 73.4%, 67.3% in the younger and 71.2%, 66.7% in the elderly subjects, respectively. MFCV and MDF recovered to initial value after fatigue more slowly in the elderly subjects (recovery time: elderly: MFCV 6.0 min., MDF 6.0 min.; younger: MFCV 2.77 min., MDF 3.00 min.) (P < 0.05, Mann-Whitney test). The over-shooting recovery phase was recognized in both age groups, but the elderly subjects had a smaller and shorter one. The slower recovery in the elderly suggested that they possibly had less potential to recovery the membrane potential propagation, metabolic capacity and more type 1 fiber composition. The smaller and shorter overshooting in the elderly might be due to less increase of muscle swelling and/or less membrane hyperpolarization.

Adult↗