Lubricating agents differ in their protection of cultured human epithelial cells against desiccation.

BACKGROUND: In dry eye, as a disease of the ocular surface, the instillation of artificial tears should compensate for the deficit in wetting and protect the mucosa against drying. MATERIAL/METHODS: The desiccation protection of different pharmacological substances was tested using the conjunctival epithelial cell line Chang 1-5c-4 (series 1) and the corneal cell line 2.040 pRSV-T (series 2). On confluent cell growth the cultures were wetted for 20 min with various preservative-free preparations of artificial tears The cell cultures were exposed to a constant air flow for 0, 15, 30 and 45 minutes. Cells were incubated with the vital dye Alamar Blue and subsequently absorption of the oxidised form of the dye was measured using an ELISA-Reader. RESULTS: Cell survival rates in series 1 after 0, 15, 30, 45 min were (1.02;0.81;0.35;0.32) for Artelac EDO, (0.82;0.69; 0.63;0.54) for Vidisic EDO, (0.77;0.80;0.67;0.70) for Vidisic Fluid EDO, (0.76;0.70;0.36; 0.34) for Acuolens, (0.97;0.46;0.35;0.33) for Viscofresh, (0.88;0.85;0.37; 0.33) for Hyal Drops SDU, (0.71;0.44;0.34;0.33) for PBS and in series 2 (1.03;0.84;-0.21;-0.20) for Artelac EDO, (0.89;0.92;0.93;0.86) for Vidisic EDO, (0.96;0.88;0.85;0.85) for Vidisic Fluid EDO, (1.01;0.75;-0.02;-0.03) for Acuolens, (0.98;0.17;-0.22;-0.20) for Viscofresh, (0.97;0.83;0.03;-0.21) for Hyal Drops SDU and (0.96;0.26;-0.24;-0.21) for PBS. Vidisic Fluid EDO and Vidisic EDO showed a significantly better protective effect after a drying period of 30 and 45 min. CONCLUSIONS: The protection capability of pharmacological substances against desiccation can be studied in a standardised cell culture system of human epithelial cell lines. Whether these in vitro results are conferrable to the efficacy of artificial tear drops in vivo has to be evaluated in clinical trials.

Secondary palatal closure in rats in association with relative maternofetal levels of folic acid, vitamin B12, and homocysteine.

Animal experiments are used in embryological and teratological studies of matters relevant to humans. In gravid rats, a decrease in the levels of folic acid and vitamin B12 was observed in maternal blood and in amniotic fluid. At the time of secondary palatal closure (14th day of pregnancy), the folic acid level of the amniotic fluid was 73% lower than that of the maternal blood. A drop in vitamin B12 in conjunction with an increase in amniotic homocysteine levels is seen as a risk factor for malformation of the palate. The understanding of causes of cleft generation could lead to a prophylactic treatment approach.