[Association study between candidate genes on transforming growth factor-ß signaling pathway and the risk of non-syndromic cleft lip with or without cleft palate in Chinese populations].

OBJECTIVE: To explore the association between 10 candidate genes on transforming growth factor-ß (TGFB) signaling pathway and non-syndromic cleft lip with or without cleft palate (NSCL/P) among Chinese populations, and to study the gene-environment interaction. METHODS: A total of 806 Chinese Han NSCL/P trios were ascertained from an international consortium, which conducted a genome-wide association study using a case-parent trio design to investigate the genes affecting risk to NSCL/P. The transmission disequilibrium test (TDT) was used to test for effects of 343 single nucleotide polymorphisms (SNPs) in 10 genes on TGFB signaling pathway including DCN, TGFB1, TGFB2, TGFB3, TGFBR1, TGFBR2, BAMBI, SMAD2, SMAD3 and SMAD4. The conditional regression models were used to test for gene-environment interaction. RESULTS: For TDT, although 19 SNPs showed nominal significant association with NSCL/P, no significant evidence of association was seen for all SNPs in 806 NSCL/P trios after Bonferroni correction. The interactions between genes and maternal smoking, environmental tobacco smoke, alcohol consumption and multi-vitamin supplementation during pregnancy did not attain statistical significance after correction for multiple comparisons. CONCLUSION: No evidence for SNP effect of genes on TGFB signaling pathway and significant gene-environment interaction was seen in our data.

[The relationship between central corneal thickness and Perkins applanation tonometry in rabbits].

OBJECTIVE: To investigate the relationship between central corneal thickness (CCT) and Perkins applanation tonometry and establish a mathematic model of correlation between true intraocular pressure (IOP), CCT and Perkins applanation tonometry. METHODS: The study included thirty-two new Zealand rabbits. One eye received excimer laser photorefractive keratectomy (PRK), the other eye was used as control. The eye selected randomly according to stochastic digital chart received PRK to thin the central cornea and to generate different central corneal thickness. The Perkins applanation tonometry, CCT, corneal curvature (CC) were measured by Perkins applanation tonometer, ultrasonic pachymetry and keratometer pre- and post-PRK. Direct intracameral IOP readings was measured by IOP transducer. Statistical analyses were performed with the Pearson correlation coefficient and stepwise regression analysis. RESULTS: There is no difference in the measurement of Perkins applanation tonometry, CCT and CC between experimental and controls. A significant correlation was found between IOP and CCT pre- and post-PRK (r = 0.761, P < 0.05; r = 0.829 P < 0.05). There is correlation between IOP and CC, (r = 0.098, P > 0.05; r = 0.260, P > 0.05). The slope of CCT was 0.066 mm Hg/micron pre-PRK and 0.053 mm Hg/micron post-PRK. However, the change of IOP correlated with CCT. Regression equation for direct intracameral IOP Y = 12.107 + 1.254X(1) - 0.033X(2) (X(1) = Perkins applanation tonometry, X(2) = CCT). CONCLUSIONS: CCT is an important variable in the evaluation of applanation IOP and should be considered when the Perkins applanation tonometry was taken.