PubMed Health⌕ Search

Biomedical subjects

R Kazusa

Publications and source records attributed to R Kazusa.

8 recordsLinked to original sources
PubMed1992

Localization of collagen (I) and collagenase mRNA by in situ hybridization during corneal wound healing after epikeratophakia or alkali-burn.

The expression and localization of type I collagen and collagenase gene were studied by in situ hybridization using rabbit cornea during wound healing following epikeratophakia or alkali-burn. In corneas 24 days after epikeratophakia, alpha 1(I) collagen mRNA was detected in keratocytes which had migrated from the host cornea into the keratolens. In contrast, collagenase mRNA was detected in cells which seemed to be inflammatory cells around the suture between the host stroma and the keratolens. The increase of alpha 1(I) collagen mRNA in keratocytes was observed in corneas 94 days after epikeratophakia and in alkali-burned corneas 1-2 months after the burn. These results provide evidence that keratocytes synthesize collagen and that this synthesizing activity lasts for a long period during corneal wound healing.

Alkalies↗
PubMed1991

Keratocyte activity in wound healing after epikeratophakia in rabbits.

Epikeratophakia is a refractive surgical procedure for the correction of aphakia, high myopia, or keratoconus. To solve clinical problems associated with epikeratophakia, a basic knowledge of its postoperative healing process is needed. The authors investigated keratocyte activities, particularly cell proliferation and collagen synthesis, during wound healing after epikeratophakia in rabbits. Epikeratophakia was done on rabbit corneas with a homologous cryolathed keratolens. Ten, 16, 28, 45, 63, 90, 254, and 360 days after the operation, the corneas were excised, labeled with either 3H-thymidine (10 microCi/ml) or 3H-proline (10 microCi/ml) for 4 hr and examined histologically and by autoradiography. Keratocytes in keratolenses were killed during the freezing process. On postoperative day 10, a few keratocytes migrated to the edge of the keratolens from the host stroma. On days 16 and 28, keratocytes in the keratolens and host stroma near the junction between the host and the keratolens incorporated 3H-thymidine, suggesting active proliferation. The proliferating activity was no longer seen after day 45. The repopulation of keratocytes was almost complete on day 90 and gradually returned to normal through day 360. Keratocytes in the keratolens and host stroma beneath the keratolens showed a higher 3H-proline incorporation than the control from days 16-254 with the highest activity at around 4-9 weeks after surgery. These results suggest that remodeling of collagen fibers continues for a long postoperative period after epikeratophakia.

Animals↗
PubMed1990

[The ultrastructural changes in the corneal lens stroma of wound healing process following epikeratophakia in rabbits].

We investigated the ultrastructural change of corneal lens+ stroma histologically following epikeratophakia in rabbits. Epikeratophakia was performed on rabbit corneas using cryolathed corneal lens+. At days 10, 16, 45, 63 and 90 after the operation, pachymetry was performed, and corneas were excised and analyzed histologically using an electron microscope. At days 16 to 63, collagen fibril density (CFD) in corneal lens+ stroma decreased 57 to 63% of that in the control cornea, but returned to 78% at day 90. The results of pachymetry revealed that postoperative increase of corneal thickness was greater than the expected value at days 10 and 16. However, after that the corneal thickness decreased gradually and became thinner than the expected value after 45 days postoperatively. At days 45 to 90, many activated keratocytes with dilated and well developed rough endoplasmic reticulum, suggestive of active collagen production, were observed in corneal lens+ stroma. Furthermore, at day 90, keratocytes with extended pseudopoidia that suggested phagocytic activity were also observed, especially in the subepithelial zone. These findings indicated that collagen fibrils in the corneal lens+ stroma were damaged under the influence of the cryolathing process and partially exfoliated postoperatively, however, collagen-producing activity increased gradually and the reconstruction of corneal lens+ stroma continued through day 90 after the operation.

Animals↗
PubMed1989

[Keratocyte activity in wound healing process following epikeratophakia in rabbits].

Epikeratophakia is a refractive surgery for the correction of aphakia, high myopia and keratoconus. Although many clinical studies of epikeratophakia have been performed, its wound healing process is not well understood. In the present study, we investigated keratocyte activities, particularly cell proliferation and collagen synthesis activity, during wound healing following epikeratophakia in rabbit corneas. Ten, 16, 28, 45, 63 and 90 days after the operation, corneas were excised, labeled with either 3H-thymidine (10 microCi/ml) or 3H-proline (10 microCi/ml) in DME for 4 hours and examined histologically, and by autoradiography. Ten days after the operation, almost no cells were seen in the keratolens except for a few keratocytes which had migrated to the edge of the keratolens. At days 16 and 28, keratocytes in the keratolens and in the host stroma near the junction between the host and the keratolens incorporated 3H-thymidine, suggesting active proliferation. The proliferating activity was no longer seen at days 45, 63 and 90. At day 90, almost complete repopulation with keratocytes was observed. Keratocytes in the keratolens and in the host stroma beneath the keratolens showed higher activity of 3H-proline incorporation than those in the control from day 16 through day 90 with the highest activity at day 28.

Animals↗
PubMed1989

[Reepithelialization of keratolens in the wound healing process following epikeratophakia in rabbits].

Most of the complications of epikeratophakia are minor and can be treated successfully. However, approximately 5 to 10% of cases of epikeratophakia result in removal of keratolenses mainly because of the failure to reepithelialize or chronic epithelial defects. In this study, in order to solve this problem we investigated the process of reepithelialization of epikeratophakia in rabbits. Epikeratophakia was performed on rabbit corneas using cryolathed keratolens. Ten, 16, 45, 63 and 90 days after the operation, corneas were excised, labeled with 3H-thymidine and examined histologically using light and electron microscope and autoradiography. 10 to 16 days after the operation, keratolenses were reepithelialized with a very thin epithelium of one or two layers. Epithelium thickened gradually, but was still thinner than normal controls at day 90. At days 10 and 16, basal cells of the epithelium showed high activity of 3H-thymidine incorporation, suggesting active proliferation. After that the proliferating activity decreased gradually and was no longer seen at day 90. Electron microscopic examination revealed no desmosomes or interdigitation between epithelial cells and poorly developed hemidesmosomes between basal cells and basement membrane at day 10, immediately after reepithelialization. At day 90, the epithelium over the keratolens showed areas where the basement membrane was irregular and extensively interrupted. These results indicated that in epikeratophakia, reepithelialization, recovery of epithelial thickness, formation of differentiated desmosomes or hemidesmosomes and normalization of ultrastructural abnormalities took longer than reepithelialization of usual epithelial defects. These results may explain the reason for of clinical problems of chronic epithelial defects or failure of reepithelialization in epikeratophakia. It was suggested that one of the factors causing delayed reepithelialization in epikeratophakia might be the cryolathing process of the keratolenses.

Animals↗