Biomedical subjects
D Orhan
Publications and source records attributed to D Orhan.
The pharmacokinetics and effects of diltiazem in rabbits.
PURPOSE: To investigate the effect of diltiazem on wound healing after the creation of conjunctival flaps in rabbit eyes. Also, to investigate the pharmacokinetics of diltiazem in rabbits after subconjunctival and topical administration. METHODS: For the histopathological study, a limbal-based flap was prepared and diltiazem was injected subconjunctivally for five days after the surgery. The rabbits were euthanised 20 days after surgery. The effectiveness of diltiazem on wound healing was evaluated by histopathological examination and measurement of the thickness of subconjunctival fibrous tissue. For the pharmacokinetic study, diltiazem was applied topically or injected subconjunctivally. Aqueous paracenteses were performed 0.5, 1, 2, 4 hours thereafter. RESULTS: The histopathological study found no difference in thickness of the subconjunctival fibrous tissue in control and diltiazem-treated eyes. No significant toxicity was observed in eyes treated with diltiazem. The peak aqueous concentration was 3.8 +/- 0.4 microg/ml after topical application and 15.3 +/- 1.1 microg/ml after subconjunctival injection. The peak aqueous concentration was achieved 1/2 hours after administration in both cases. CONCLUSIONS: Diltiazem did not appear to affect wound healing at the dose tested. Topical and subconjunctival diltiazem successfully penetrated the aqueous humor of rabbit eyes.
Lacrimal sac dacryolith: a study wit atomic absorption spectrophotometry and scanning electron microscopy.
Dacryoliths are uncommon causes of partial or complete obstruction of the nasolacrimal drainage apparatus. We report our findings of a dacryolith that we studied by culture, light microscopy, atomic absorption spectrophotometry, and scanning electron microscopy. Although no fungi were recovered by culturing, hyphae-like structures were observed. No inorganic material was detected by atomic absorption spectrophotometry. Scanning electron microscopy of ultrastructure showed the stone was composed of lobes and lobules built on an amorphous core material.
Expression of p53 protein in pterygium.
PURPOSE: The pathogenesis of pterygium is still not completely understood and many environmental factors, including ultraviolet (UV) radiation, play an important role in its etiology. Chronic exposure to UV radiation causes mutations in the p53 tumor suppressor gene, eventually leading to tumor formation. We analyzed the immunohistochemical expression of p53 proteins in pterygial tissues to determine the role of the p53 tumor suppressor gene in the development of pterygium. METHODS: Pterygial specimens were studied immunohistochemically using antibodies against p53 protein. RESULTS: Out of 38 specimens studied, 35 (92.1%) had conjunctival epithelial cells without p53 specific nuclear staining. Only three specimens (7.9%) had a few p53 stained cells. The role of UV radiation in the pathogenesis of pterygium is supported by epidemiological, geographical and microscopic findings. However, our results are not consistent with these data on a genetic basis. CONCLUSIONS: We conclude that defective p53 tumor suppressor gene function seems to have no role in the pathogenesis of pterygium.
Dry eye syndrome associated with Urbach-Wiethe disease.
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