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Biomedical subjects

M Sawa

Publications and source records attributed to M Sawa.

At least 19 recordsLinked to original sources
PubMed1995

P element-induced mutations in Drosophila melanogaster showing high interspecific crossability between D. melanogaster females and D. simulans males.

Homozygous stocks for the second or the third chromosome of Drosophila melanogaster with a single insertional plwB element were screened for high crossability with D. simulans. Reciprocal crosses between each of these stocks and D. simulans were made, and the insemination rate at two or three days was examined. From two cycles of screening of the original 575 stocks, one stock (# 687) which showed high insemination rate was selected and was backcrossed to a w strain to substitute the background. We obtained a stock which showed 10% insemination rate with D. simulans males (control was 0%). No stocks exhibiting a high crossability with D. simulans females were acquired. Revertant strains, from which the P element had been lost, were obtained from the backcrossed # 687 stock. The insemination rates of 13 revertants to D. simulans males ranged from 1% to 33%. Seven of these 13 were not significantly different from the control line but were significantly different from the backcrossed # 687 stock. It was concluded that the mutation showing high crossability with D. simulans males was caused by the P element transposition.

Animals↗
PubMed1995

Epistatic interactions among the P element-induced high interspecific crossability strains in Drosophila melanogaster.

Five Drosophila melanogaster strains showing high interspecific crossability with D. simulans males, derived from the previous screening of a set of autosomal plwB transposants, were selected and the effect of the plwB insertion under the same genetic background (white strain) on the interspecific crossability was examined. This phenotype was recessive in the two strains but semidominant in the other three strains. Trans-heterozygotes, however, showed high interspecific crossability compared with the parental homozygotes, suggesting some epistatic interactions between them. In three strains, the effect of the plwB insertion region in different backgrounds (w1118 strain) on the crossability was also tested. Homozygotes of a strain (#687) showed high interspecific crossability comparable to the w background, while homozygotes of both #68 and #783 strains showed lower crossability than w1118. Although #783 heterozygotes showed intermediate values between #783 homozygotes and w1118, #68 heterozygotes showed a significantly higher insemination rate than w1118 and the #68 homozygotes. These results suggest that the region around the plwB insertion sites of #68 and #783 affects the interspecific crossability either positively or negatively depending on the genetic background. In all the stocks, positive correlation between interspecific crossability and the intraspecific mating speed was detected.

Animals↗
PubMed1995

[The time required topical carbonic anhydrase inhibitor (MK-507) to take effect on intraocular pressure of normal human eyes].

The effective time course of a topical carbonic anhydrase inhibitor, MK-507, on intraocular pressure (IOP) was studied in 6 normal volunteers. As a baseline study, IOP was determined and aqueous protein concentration was determined by laser flare photometry every half hour for 5 hours with the instillation of a placebo. Then, an examination with the same time course was performed on the same subjects with the instillation of 1% MK-507 or oral administration of acetazolamide at a dose of 250 mg. MK-507 lowered IOP 30 minutes after the instillation, and showed a significant reduction of IOP at 1 hour. Aqueous protein concentration increased significantly 30 minutes after the MK-507 instillation. Acetazolamide lowered IOP 30 minutes after the administration, and showed a significant reduction of IOP at one hour. Aqueous protein concentration increased significantly one hour after the acetazolamide administration. Corneal thickness, anterior chamber depth, anterior chamber volume, and serum protein concentration were not significantly changed by the drug treatment. These results suggest that the inhibition of aqueous humor production causes the rapid reduction of IOP seen in the use of MK-507 as well as acetazolamide.

Administration, Topical↗
PubMed1995

[Histological study of allergic conjunctivitis--1. Study on the adhesion molecules to allergic conjunctivitis].

We performed an immunohistochemical study on the relationship between inflammatory cells and adhesion molecules to investigate inflammatory reaction in allergic conjunctivitis. Guinea pigs were sensitized with an intraperitoneal injection of ovalbumin with hydroxyalminium. Ovalbumin was applied topically to the conjunctiva 3 weeks after the initial treatment. Then the cornea, conjunctiva and lacrymal gland were taken and processed for frozen sections. The specimens were stained with acid Giemsa for inflammatory cells and enzyme-labelled antibody for ICAM-1 and VCAM-1. Neutrophils were dominantly observed 6 hours after the challenge with the antigen, eosinophils at 12 hours, and eosinophils and lymphocytes at 24 hours, respectively. ICAM-1 and VCAM-1 were detected at 6 and 24 hours in the vascular tissue in the subconjunctival tissue and lacrymal gland. There results suggest that adhesion molecules play a role in the infiltration of inflammatory cells in allergic conjunctivitis.

Animals↗
PubMed1995

[Anterior chamber inflammation after cataract intraocular lens surgery in postvitrectomy eyes].

We determined the anterior chamber inflammation by means of laser flaremetry after cataract intraocular lens surgery for the nuclear cataract that developed after vitrectomy. Cases (38 eyes of 36 patients) were divided into the following four groups according to their pathologies indicating vitrectomy; proliferative diabetic retinopathy (PDR, 14 eyes), idiopathic posterior vitreous membrane syndrome (PVMS, 9 eyes), rhegmatogenous retinal detachment (RRD, 8 eyes), and branch retinal vein occlusion (BRVO, 7 eyes). Mean intervals between the two surgeries were 31, 23, 27 and 18 months, respectively. Phacoemulsification and aspiration through the self-sealing sclerocorneal wound and intraocular lens implantation in the bag were performed. The mean flare count was already high before the cataract surgery in all groups. Postoperative course of mean flare count was an overlap of two waves, one (P1) with a peak on day 1 followed by rapid decrease and the other (P7) with a peak on day 7 followed by slow decrease. Peak values of P1 were higher than the day 1 value after cataract surgery without fundus pathology, and higher in PDR and BRVO groups than in PVMS and RRD groups. P7 was like that observed after vitrectomy and there was close similarity among the groups.

Aged↗
PubMed1995

Circadian rhythms in aqueous protein concentration and intraocular pressure in rabbits.

Circadian rhythms in aqueous protein concentration (APC) and intraocular pressure (IOP) were examined in Dutch rabbits using the laser flare-cell meter and a pneumatonometer. The reproducibility and seasonal changes in circadian rhythm were also investigated. Rabbits were trained to a lighting cycle of 12-hour light and 12-hour darkness. The mean value of reproducibility coefficients obtained with re-examination at 2-week intervals was 21.9% in the reading of the laser flare-cell meter. APC was reduced during the dark phase, and increased rapidly and remained high during the light phase. On the other hand, IOP showed an inverse circadian rhythm which was negatively correlated with that of APC. The total average of APC throughout 24 hours was 39.1 +/- 28.3 (mean +/- SD) mg/100 ml equivalent of bovine serum albumin, which agreed with the previous data. Seasonal changes in circadian rhythm were not statistically significant either in APC or in IOP.

Animals↗
PubMed1992

Cortical area related to lens accommodation in cat.

Lens accommodation was evoked by microstimulation in the lateral suprasylvian (LS) area in cats. The accommodative response was monitored continuously with an infrared optometer. The low threshold areas related to lens accommodation were located in the lower parts of the medial banks of the middle suprasylvian sulcus from A1 to A4, and also in the fundus of the sulcus at A8 in the stereotaxic coordinates. The latency of the onset of the accommodative responses evoked by stimulating the caudal area (A1-A4) was shorter than that evoked by stimulating the rostral area (around A8). Electrical stimulation was also attempted at the subcortical area in order to study the output pathway from the LS area. It was determined that the low threshold sites in the LS cortex of A1-A4 extend rostrally along the lateral ventricle in the brainstem, then ventrally into the midbrain. These findings suggest that there are two cortical areas related to lens accommodation: caudal and rostral, and the caudal accommodation area may provide the output signal for the subcortical system.

Accommodation, Ocular↗
PubMed1992

Keratoepithelioplasty in rat: development of a model and histological study.

A model for keratoepithelioplasty (KEP) was developed using the Lewis rat, and histological studies were performed using this model. The entire corneal epithelium was removed mechanically and a 1.5-mm width of the conjunctiva including the limbus was excised. An oval corneal lamellar graft (3 x 1.5 mm) with an intact epithelium taken from another Lewis rat was transplanted on the denuded limbus. Biomicroscopic observations showed much less vascular invasion in the part of the cornea adjacent to the lenticule than in other parts of the cornea, and the cornea remained clear adjacent to the lenticule. Histologically, a few vessels were observed in the corneal stroma under the lenticule. Epithelial cells on the lenticule specimens showed histological characteristics of the corneal epithelium. These findings indicate that one of the functions of KEP is to block neovascularization in the newly developing corneal epithelium by transplanting the lenticule between the corneal epithelium and conjunctival vessels. The present study also confirmed that this model is useful in the research of the pathophysiological mechanism of KEP.

Animals↗
PubMed1992

[Histological study of a model of keratoepithelioplasty in the rat].

A model for keratoepithelioplasty (KEP) was developed using the Lewis rat, and histological studies were performed using the model. The entire corneal epithelium was removed using a spatula and a 1.5-mm-width of the conjunctiva including the limbus was excised. An oval corneal lamellar graft (3 x 1.5 mm) with an intact epithelium taken from another Lewis rat was transplanted on the denuded limbus. Biomicroscopic observation showed significantly less vascular invasion in the part of the cornea adjacent to the lenticule than in other part of cornea, and clear cornea was maintained in the cornea adjacent to the lenticule. Histologically only few vessels were recognized in the lenticule, and the epithelial cells on the lenticule showed histological characteristics of corneal epithelium. These results indicate that surgical function of KEP can be obtained because the lenticules keep distance between corneal epithelium and conjunctival vessels. And it is also confirmed that this model is useful in research on the pathophysiological mechanism of KEP.

Animals↗
PubMed1992

[A case of peripheral corneal ulcer accompanied by progressive systemic sclerosis].

A 61-year-old woman with progressive systemic sclerosis developed bilateral peripheral corneal ulcer. The corneal lesions were resistant to daily systemic treatment with 15 mg steroid and 50 mg cyclophosphamide. Corneal perforation occurred in her right eye 11 months after the onset of Raynaud's phenomenon and 3 months after the scleritis. Lamellar keratoplasty accompanied with Brown's operation was performed on both eyes. Graft melt and cicatricial corneal opacity developed postoperatively. Removed conjunctival tissue was examined immunohistochemically. HLA-DR protein positive monocytes infiltrated subepithelial tissue, demonstrating that the inflammation of the lesions was in the active stage. Not only perforin but also suppressor/cytotoxic T cell positive reactions were observed, which revealed an involvement of the T cell immune system in the present case.

Corneal Ulcer↗
PubMed1992

[Aqueous protein concentration in diabetics. Report 5. Relationship between aqueous protein concentration and pathological findings of iridial vessels].

The relationship between aqueous protein concentration (APC) and pathological changes in the iridial blood vessels was investigated in 49 eyes of 45 diabetic patients who underwent cataract surgery. APC was measured with a laser flare-cell meter before surgery. The quantification analysis method (type I, multivariate analysis) revealed that the most relevant factor to APC was the existence of nephropathy followed by, in descending order, the degree of retinopathy and changes in iridial vessels as demonstrated by electron microscopy. When data were reanalyzed after exclusion of the iridial vessels were found to be strongly relevant to APC. These results suggest that breakdown of the blood-retinal barrier contributes to the APC increase in eyes with advanced diabetic retinopathy, and that changes in iridial vessels may mainly influence APC in non- and milder-retinopathy groups.

Aged↗
PubMed1992

[Corneal endothelial cell damage in penetrating keratoplasty].

Fifty-eight corneal grafts were investigated by specular microscopy to determine the corneal endothelial damage in penetrating keratoplasty. The center of the donor corneal endothelium was examined before and after 2 weeks, 1, 3, 6 and 12 months after surgery. The cell density decreased periodically during the observation period, and the endothelial cell loss in all the cases averaged 10. 4% at 2 weeks after the operation, 16.0% at 1 month, 33.0% at 3 months, 39.4% at 6 months, and 48. 2% at 12 months. However, the cell loss in the keratoconus subgroup averaged -1.9%, 1.2%, 9.9%, 30. 6%, and 33.4% corresponding to the above period. The least cell loss among the diagnostic subgroups was in the keratoconus, followed by corneal leukoma. The cell loss in bullous keratopathy was higher than in keratoconus and corneal leukoma case. It was concluded that the cell loss in penetrating keratoplasty during the first postoperative year depends on the primary disease.

Adolescent↗
PubMed1991

Severe corneal edema after prolonged use of psychotropic agents.

A 23-year-old woman with schizophrenia who had been treated with a high dose of psychotropic agents for 6 years had bilateral corneal edema and suffered from severe visual disturbance. No signs of inflammation, infection, congenital abnormality, or corneal endotheliitis were observed. The symptoms did not respond to either topical or systemic treatments. Reduction in the dosage of psychotropic agents resulted in quick and complete disappearance of the corneal edema within 2 weeks. Specular microscopic examination after recovery revealed a marked enlargement of corneal endothelial cells, but there was no evidence of any corneal dystrophy. Blood-aqueous barrier function was not deteriorated, as demonstrated by aqueous protein concentration measured with a laser flare-cell meter. In conclusion, we suggest that corneal edema may be caused by prolonged use of psychotropic agents, particularly a major tranquilizer.

Adult↗
PubMed1991

Corneal endothelial cell damage in penetrating keratoplasty.

Fifty-eight corneal grafts were examined by specular microscopy to determine the corneal endothelial cell damage following penetrating keratoplasty. The average postoperative follow-up period was 10.1 months. The cell density decreased continuously during the observation period, and the endothelial cell loss of the central area of the cornea in all the cases averaged 10.4% at two weeks after the surgery, 16.0% at one month, 33.0% at three months, 39.4% at six months, and 48.2% at one year. However, the cell loss in the keratoconus group averaged -1.9, 1.2, 9.9, 30.6 and 33.4% for the corresponding postoperative periods. The cell loss in the bullous keratopathy eyes showed higher values compared to those in the keratoconus and the corneal leukoma eyes. It was concluded that cell loss in penetrating keratoplasty during the first postoperative year depends on the host diseases.

Adolescent↗