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Biomedical subjects

T Awata

Publications and source records attributed to T Awata.

At least 91 records · Page 5Linked to original sources
PubMed1989

The effect of long-term topical administration of commercial beta-blockers on the rat corneal endothelium.

To determine the effect of long-term topical application of commercial beta-blockers on the corneal endothelium, normal rats were randomly assigned to receive a drop of 0.5% timolol, 1% befunolol, or 2% carteolol four times daily for 8 months. Specular microscopy showed marked pleomorphism in the endothelium after three months of treatment with 1% befunolol. In contrast, the eyes treated with either 0.5% timolol or 2% carteolol demonstrated no significant change in endothelial morphology. Scanning and transmission electron microscopy at eight months after treatment revealed marked degeneration of the endothelium of the eyes treated with 1% befunolol. Similar endothelial changes were also noted in the 0.5% timolol-treated group, but to a significantly lesser extent. The eyes treated with 2% carteolol, however, showed only mild alteration of the endothelial ultrastructure. These results indicate that the corneal endothelium can be affected by long-term topical administration of commercial beta-blockers.

Administration, Topical↗
PubMed1989

Intraocular penetration of CT-112, an aldose reductase inhibitor, following topical instillation.

Intraocular penetration of 5-(3-ethoxy-4-pentyloxyphenyl)thiazolidine-2,4-dione (CT-112), an aldose reductase inhibitor, was investigated in rabbits following topical instillation. The concentration of CT-112 in corneal epithelium, stroma, endothelium, lens, and aqueous humor, was sequentially determined by high-performance liquid chromatography. CT-112 peaked in the corneal epithelium, stroma, endothelium and aqueous humor in 30 minutes following instillation, then gradually diminished time-dependently over a period of 24 hours. CT-112 remained detectable in the lens up to 24 hours, with a peak concentration at 2 hours after instillation.

Administration, Topical↗
PubMed1989

A 595 nanometer band-pass filter enhances the contrast of in situ hybridization signals on chromosome observed after biotin/avidin-alkaline phosphatase localization.

In situ hybridization with DNA probes labeled with biotin and detected by the avidin-alkaline phosphatase/5-bromo-chloroindoxyl phosphate-nitro blue tetrazolium system has been used to localize DNA sequences in chromosomes. To observe the hybridization signals, a phase contrast microscope has often been used because of the good visibility it provides. Use of a 595 nm band pass filter with the phase contrast microscope enhances signal contrast after in situ hybridization without reducing resolution.

Alkaline Phosphatase↗
PubMed1989

Differential regulation of fibronectin synthesis in three different types of corneal cells.

The production of fibronectin (FN) and its response to serum or epidermal growth factor (EGF) were investigated in three different types of rabbit corneal cells cultured in vitro. The corneal epithelial cells, stromal fibroblasts (keratocytes) and endothelial cells were separately cultured in different media: basic medium containing minimal serum (0.5%), basic medium with supplementary serum at a final concentration of 10% and basic medium with 100 ng/ml EGF, respectively. FN production by each type of cell was examined either by the immunofluorescent staining method or by the metabolic labeling method followed by immunoprecipitation of FN in the culture medium. Each type of corneal cell produced and secreted FN. FN secretion into the culture medium by keratocytes and by endothelial cells was enhanced by the addition of EGF. However, FN secretion by epithelial cells was lowered by the additional serum or EGF. Furthermore, when the epithelial cells were cultured in the basic medium, DNA synthesis was low but FN secretion was high. These results suggest that the control mechanism of FN production differs between epithelial cells and keratocytes or endothelial cells.

Animals↗
PubMed1988

HLA DR antigens in adult-onset and juvenile-onset Japanese insulin-dependent diabetic patients.

In order to discover the HLA DR antigens linked to Japanese insulin-dependent diabetes (IDDM), and to relate them to the clinical features, HLA DR antigens were examined in 75 IDDM patients including 56 adult-onset cases. Among the tested HLA DR antigens, 4, w9 and w13 were significantly more frequent in IDDM (55%, 47% and 27% respectively). The relative risk was 1.71 for DR4, 2.81 for DRw9 and 4.74 for DRw13. DR2 was significantly less frequent and the relative risk was 0.14. The distribution of DR antigens did not differ between juvenile-onset and adult-onset IDDM, males and females, or cases with and without thyroid autoantibodies. Homozygotes for DRw9 were, but those for DRw13 and DR4 were not more frequent than expected by a random combination. Heterozygotes for DR4 and w9 were less frequent while other heterozygotes for high-risk antigens were as frequent as expected. 97% of IDDM had either DR4, w9 or w13. In conclusion, HLA DR4, w9 and w13 were significantly increased in patients with both juvenile- and adult-onset IDDM. There was no surplus increase in the frequency of IDDM patients with two high-risk HLA DR antigens, more than expected from random combination of each of these DR antigens. Clinical features did not differ among IDDM patients with each of these three antigens.

Adult↗
PubMed1988

Enhancement of the sensitivity for in situ detection of alkaline phosphatase using a homopolymer of 2-acrylamide 2-methylpropanesulfonate.

In order to enhance the sensitivity of detection of alkaline phosphatase immobilized on nitrocellulose, a homopolymer of 2-acrylamide 2-methylpropanesulfonate (poly-AMPS) and agarose were added to the reaction mixture using 5-bromochloroindoxyl phosphate and nitroblue tetrazolium. By addition of the above ingredients, the amount of the reaction product deposited on the nitrocellulose filters on which alkaline phosphatase had been dot-blotted was increased, and darkening of the background (un-dot-blotted area) was prevented. Reflective densitometry revealed that the addition of poly-AMPS and agarose increased the sensitivity of the detection approximately three times higher than without the use of these compounds.

Acrylamides↗
PubMed1988

Effect of an aldose reductase inhibitor, CT-112, on healing of the corneal epithelium in galactose-fed rats.

The effect of an aldose reductase inhibitor, CT-112 (5-(3-ethoxy-4-pentyloxyphenyl)2,4-thiazolidinedione), ophthalmic solution on wound healing in the corneal epithelium of rats fed on 50% galactose diet was investigated in correlation with CT-112 concentration. Rats were divided into 6 groups and those in 5 groups were fed on 50% galactose diet and 10 microliter of 0.1, 0.25, 0.5 and 1% CT-112 ophthalmic solutions or of their vehicle were instilled into both eyes 4 times a day. The animals in the remaining one group were fed on the regular diet and no treatment was given. After 18 days, the whole corneal epithelium was scraped off and the rate of reepithelialization was investigated over a 4-day period. Reepithelialization was delayed in galactosemic rats, but the instillation of CT-112 ophthalmic solutions improved the wound healing, although no differences in efficacy was found at the concentrations used. Moreover, the appearances of the cornea at 4 days after epithelial scraping were improved dose-dependently by the instillation of CT-112.

Aldehyde Reductase↗
PubMed1988

Identification of nucleotide substitution in gene encoding [LeuA3]insulin in third Japanese family.

We previously described a new case of abnormal insulinemia in Japan. In one allele, nucleotide-sequence analysis revealed a substitution in the codon for the third position of insulin A chain (GTG----TTG), causing [LeuA3]insulin. This point mutation is the same as that found in insulin Wakayama. In this family, the mutant insulin allele cosegregated with an 850-base pair PvuII allele of the hypervariable region 5'-flanking the insulin gene.

Base Sequence↗
PubMed1987

The effects of aldose reductase inhibitor on the corneal endothelial morphology in diabetic rats.

Diabetic rats were produced by intravenous injection of streptozotocin. Of these, eleven rats were treated with topical instillation of 0.5% aldose reductase inhibitor (ARI), while ten received vehicle alone. The corneal endothelium of these diabetic rats was examined by specular microscopy and compared to age-matched nondiabetic rats (ten rats). Computerized morphometric analysis of individual cells demonstrated that the endothelium of the untreated diabetic rats had marked polymegathism (increased coefficient of variation in cell area) and pleomorphism (decreased percentage of hexagonal cells), as previously observed in diabetic patients. Similar endothelial changes were also noted in the ARI-treated diabetic rats, but to a significantly lesser extent. These results suggest that topically applied ARI can be effective in reducing morphologic changes of the diabetic endothelium, and that activation of the sorbitol pathway may be implicated in the etiology of such endothelial changes.

Aldehyde Reductase↗
PubMed1986

Effects of aldose reductase inhibitor, CT-112, on sugar alcohol accumulation in corneal epithelium of galactose-fed rats.

A study was made of inhibitory effects of an aldose reductase inhibitor, CT-112 (5-(3-ethoxy-4-pentyloxyphenyl)-2,4-thiazolidinedione) ophthalmic solution, on the accumulation of sugar alcohol (dulcitol) in the corneal epithelium of rats fed on a 50% galactose diet. The effects were correlated with the concentrations of the drug solution. The rats were divided into 6 groups. One group was fed on a regular laboratory chow and was untreated. The other 5 groups were fed on a 50% galactose diet, and 0.1, 0.25, 0.5 or 1.0% CT-112 ophthalmic solution or its vehicle was instilled in both eyes 4 times a day in each of the 5 treated groups. After 2 weeks, the corneal epithelium was scraped off in all rats and its dulcitol content was determined by gas chromatography. CT-112 ophthalmic solution was found to inhibit the accumulation of dulcitol in a dose-dependent manner, except for the 1.0% solution which had an activity comparable to the 0.25% solution.

Aldehyde Reductase↗
PubMed1985

Restriction fragment length polymorphism of the insulin gene region in Japanese diabetic and non-diabetic subjects.

A polymorphic locus flanking the 5' end of the insulin gene was studied in 154 unrelated Japanese diabetic and nondiabetic subjects. A predominance of the small allele was found with the following frequency: of 64 nondiabetic subjects, only 3 of 128 alleles were of the large class (2%); none of 78 alleles were of the large class in 39 Type 1 (insulin-dependent) diabetic subjects, and 4 of 102 alleles (4%) were of the large class in 51 Type 2 (non-insulin-dependent) diabetic subjects. The very low frequency of large allele may relate to the lower prevalence of atherosclerosis in Japanese. However, this possibility requires further examination.

Alleles↗
PubMed1984

Alteration of beta-cell function in different diabetic states.

To assess the effects of metabolic control upon beta cell function in diabetes, pro-insulin and insulin were determined following gel-filtration of plasma at two time points in each three diabetic patients, once when the metabolic state was severely deranged and again after the metabolic state had improved after therapy. Before therapy, proinsulin concentration were 30 pM (as IRI), both fasting and at 2 hours after an oral glucose load. These values did not change with treatment. Insulin concentrations were 22 pM at both time points before therapy. With treatment, plasma insulin increased 2-fold at fasting and 7-fold at 2 hours after oral glucose. These results suggest an exhaustion of the insulin pool in beta cells during severe metabolic decompensation of diabetes, a condition which may be reversed by correction of the metabolic states of the patients with proper therapy.

Acromegaly↗
PubMed1984

Growth of skeletal bones and their sexual differences in mice.

An experiment was conducted in 76 mice (3 to 9 weeks of age) to investigate the characteristics in growth of major skeletal bones and their sexual differences. The length of ulna, radius, femur and tibia attained their maximum growth rate at earlier age, and showed no sexual difference in their growth patterns. Scapula length and width, humerus length and os coxae width reached the maximum growth rate at a later age than the forearm and shank, and showed no sexual difference in their growth, although those bones presented larger adult sizes for male than female. The length of vertebrae showed significant sexual differences in their growth patterns and adult sizes, except for lumber vertebrae. A significant sex difference in body weight caused the sexual differences in relative growth of bones to body weight. According to their relative growth to the length of humerus, the skeletal bones could be well grouped into three categories. A significant sexual difference was seen in the relative growth of scapula length. In general, it seemed that the bones growing in a vertical direction grew earlier than the bones growing in a horizontal direction, especially those of the forearm and shank. The results obtained in mice were in good agreement with the findings in pigs.

Age Factors↗