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Biomedical subjects

D Balasubramanian

Publications and source records attributed to D Balasubramanian.

77 records · Page 5Linked to original sources
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Photodynamics of cataract: an update on endogenous chromophores and antioxidants.

Cataract of the eye lens is characterized by (1) progressive opacification or loss of transparency; (2) accumulation of molecules that absorb in the UV-visible range of the spectrum; and (3) formation of fluid-filled vacuoles, particularly in diabetics when sugar levels in the lens are high. Of the various causative factors for cataract, light is an important one. Because the level of light below 320 nm reaching the lens is quite low, photodynamic effects of endogenous compounds absorbing in the UV-A-visible region become important in this connection. In this update we summarize a list of accumulant chromophores that have been identified in aging and cataract human lenses and their roles as potential sensitizers, antioxidants or as benign filters. Because such photodynamic cataractogenesis is oxidative in nature, we also cite examples where administration of antioxidants could help delay cataract progression.

Aging↗
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Technique of cultivating limbal derived corneal epithelium on human amniotic membrane for clinical transplantation.

BACKGROUND: The technique of transplantation of cultivated limbal epithelium rather than direct limbal tissue isa novel method of "cell therapy" involved in reconstructing the ocular surface in severe limbal stem cell deficiency [LSCD], caused by chemical burns. AIM: To describe a simple feeder-cell free technique of cultivating limbal epithelium on human amniotic membrane[HAM]. MATERIALS AND METHODS: The limbal tissues (2 mm) were harvested from patients with LSCD. These tissues were proliferated in vitro on HAM supplemented by human corneal epithelial cell medium and autologous serum. Cultures covering more > or = 50% area of 2.5 x 5 cm HAM were considered adequate for clinical use. The cultured epithelium was characterized by histopathology and immunophenotyping. RESULTS: A total of 542 cultures out of 250 limbal tissues were cultivated in the laboratory from January 2001 through July 2005. The culture explants showed that clusters of cells emerging from the edge of the explants in one-three days formed a complete monolayer within 10-14 days. In 86% of cultures (464 of 542), the growth was observed within one-two days. Successful explant cultures were observed in 98.5% (534 of 542 cultures) with 91% explant cultures showing an area of > or = 6.25 cm2 (6.25 - 12.5 cm2 range). The cultivated epithelium was terminated between 10-14 days for clinical transplantation. The problems encountered were inadequate growth (2 of 542) and contamination (2 of 542). CONCLUSIONS: We demonstrate a simple technique of generating a sheet of corneal epithelium from a limbal biopsy. This new technique could pave the way for a novel form of cell therapy.

Amnion↗