Effect of intravitreal anti-vascular endothelial growth factor on corneal endothelial cell count and central corneal thickness in Indian population.

PURPOSE: To evaluate the effect of intravitreal anti-VEGF on corneal endothelial cell count and central corneal thickness as well as to compare these in phakic and pseudophakic eyes. MATERIAL AND METHODS: The study was conducted in 102 eyes selected, as per selection criteria, over a time period of 18 months. At first patient visit, examination included: 1. Fundus examination. 2. Specular microscopy was done to look for endothelial cell count and Central corneal thickness. At second visit, Injection 0.5 mg/0.05 ml of ranibizumab was administered. Visits at day 1, day 7 and 1 month were done for Endothelial cell density and central corneal thickness was measured by specular microscope. RESULTS: The mean CCT value in pseudophakic group was 502.08 ± 19.91, 501.9 ± 20.31, and 501.72 ± 21.55 on day 1, 7 and 30, respectively. The mean CCT value in phakic group was 506.53 ± 22.61, 505.96 ± 20.12, 505.92 ± 20.3 and 505.69 ± 21.47. The mean value of ECD in pseudophakic eyes on day 1, 7, and 30 were 2284.24 ± 299.86, 2281.39 ± 289.46 and 2284.06 ± 312.65 cells/mm2, respectively. The mean value of ECD in phakic eyes on day 1, 7, and 30 were 2314.51 ± 212.08, 2313.92 ± 212.7 and 2313.63 ± 216.86 cells/mm2, respectively. CONCLUSION: There is no significant change in endothelial cell density, central corneal thickness, coefficient of variation and intraocular pressure before and after intravitreal injection over one month of follow-up. The results are similar between phakic and pseudophakic eyes.

Expression of Wnt signalling pathway genes during tooth development.

We have carried out comparative in situ hybridisation analysis of six Wnt genes Wnts-3, -4, -5a, -6, -7b, and 10b together with Wnt receptor MFz6 and receptor agonist/antagonists MFrzb1 and Mfrp2 during murine odontogenesis from the earliest formation of the epithelial thickening to the early bell stage. Expression of Wnt-4, Wnt-6, and one Wnt receptor MFz6 was observed in the facial, oral and dental epithelium. Wnt10b was localised specifically to the presumptive dental epithelium. Wnts-3 and -7b were expressed in oral epithelium but showed no expression in the presumptive dental epithelium. Wnt-3 also showed no expression in the epithelial cells of the molar bud stage tooth germs, but showed restricted expression in the enamel knots which are signalling centres believed to be involved in regulating tooth shape. Wnts -6, -10b and MFz6 were also detected in the primary and secondary enamel knots. Wnt-5a and agonist/antagonists MFrzb1 and Mfrp2 were expressed in a graded proximo-distal (P-D) manner in mesenchymal cells during the early stages of tooth development with no overlying expression in the oral or dental epithelium. Wnt-5a and MFrzb1 show strong expression in the dental papilla mesenchyme.

Inhibition of Wnt signaling by exogenous Mfrzb1 protein affects molar tooth size.

Wnt extracellular signaling molecules have essential roles as regulators of cell proliferation, migration, differentiation, and in epithelial-mesenchymal interactions involved in tissue morphogenesis. Frizzled integral membrane proteins have been shown to function as receptors for Wnt signaling molecules. Vertebrates also produce secreted proteins related to Frizzled receptors, Frizzled-related proteins (FRPs), which contain the cysteine-rich domain of Frizzleds and appear to function as Wnt antagonists. Tooth development is regulated by a reciprocal series of epithelial-mesenchymal interactions, and many Wnt signaling pathway genes are expressed in the developing tooth at these sites. Here we report the expression of one FRP gene, Mfrzb1, in the rostral mesenchyme of the mandibular primordium. Using explant cultures, we show that expression of Mfrzb1 in the mandibular mesenchyme is under the control of signals derived from the overlying epithelium. Bead implantation experiments in vitro show that FGF8 induces Mfrzb1 expression, whereas BMP4 and SHH proteins have no effect. We studied the effect of ectopic MFrzb1 protein on the developing tooth germs by transplanting explants treated with Mfrzb1 protein into renal capsules, and found it to retard tooth development. This suggests that Wnt signaling is required early in tooth germ formation and that interference with signaling via addition of an antagonist results in retarded development and formation of smaller teeth.

Effects of heat stress on mouse testicular cells and sperm chromatin structure.

Scrotal regions of mice were exposed to a 38.0, 40.0, or 42.0 degrees C (+/-0.1) H2O bath for 60 minutes to determine the effects of elevated temperatures on testicular cells and sperm chromatin structure. Mice were killed on various days after exposure, and ratios of acridine orange-stained testicular cell populations were determined by flow cytometry. Testicular weights of mice exposed to 42.0 degrees C decreased significantly day 1 (P < 0.01) through 35 (P < 0.001). Also, a significant relative decrease in testicular haploid cells was seen on days 3-35 (P < 0.001) with a corresponding increase in the diploid population (P < 0.001). Testicular analyses of mice exposed to 38.0 degrees C were not significantly different from control values. Testis weights of mice exposed to 40.0 degrees C were not affected, but a relative decrease in percent haploid cells occurred on days 11 and 14 (P < 0.001). The sperm chromatin structure assay (SCSA) was used to measure the susceptibility of cauda epididymal sperm DNA to in situ denaturation at low pH. Caudal epididymides of mice exposed to 42.0 degrees C had no sperm. Caudal epididymal sperm from mice exposed to 40.0 degrees C were most susceptible to acid-induced DNA denaturation on days 3 (P < 0.05), 7, 11, and 14 (all P < 0.001). The 38.0 degrees C exposed mice showed some minor sperm chromatin abnormalities at later time points (days 11-35). When compared to sperm head morphology measurements, SCSA parameters were more sensitive indicators of heat-induced sperm abnormalities. These results show that mouse spermatogenesis is disrupted by scrotal exposure to environmental temperatures several degrees over normal physiological temperature and, of more biological interest, that some thermal ranges above normal allowed production of sperm with compromised nuclear chromatin structure.

Antithiamine factor in cotton seed (Bombex malabericum)--its isolation and characterization.

1. The antithiamine factor isolated from cotton seed (Bombex malabericum) was a light yellow amophous substance. 2. 1 mg of this antithiamine factor inactivated 20.5 mug of thiamine hydrochloride. 3. The antithiamine factor was characterized as 3,5-dimethoxy salicylic acid.

Nutritional studies of 3,5-dimethyoxy salicylic acid (antithiamine) on rat as well as on the growth of S. aureus.

1. The growth of rats treated with 3,5-dimethyoxy salicylic acid was retarded in comparison to that of normal rats. 2. The free cholesterol level of plasma of rats treated with 3,5-dimethoxy salicylic acid diminished while the pyruvate level of erythrocyte under the same condition increased in comparison with their normal levels; but on administration of thiamine both the cholesterol and pyruvate levels became normal. 3. The growth of a thiamine dependent strain of S. aureus was retarded when the organism was incubated in the medium containing 3,5-dimethoxy salicylic acid and this growth can be restored with the supplementation of thiamine in the medium.

Wnt/Shh interactions regulate ectodermal boundary formation during mammalian tooth development.

Interactions between the Wnt (wingless) and hedgehog signaling pathways were first described as playing a role in establishing boundaries between ectodermal cells in Drosophila segmentation. During the initiation of mammalian tooth development, boundaries that distinguish oral from dental ectoderm must be formed to correctly position the sites of tooth formation. We describe a reciprocal relationship between the expression of Wnt-7b in presumptive oral ectoderm and Shh in presumptive dental ectoderm in mouse embryos that mark boundaries between these cells with different developmental fates. By using a murine retrovirus to ectopically express Wnt-7b in presumptive dental ectoderm in mandibular arch explants, we show that Shh expression in the ectoderm and Ptc expression in the underlying ectomesenchyme are down-regulated, and tooth development is subsequently arrested. This suggests that Wnt-7b acts to repress Shh expression in oral ectoderm, thus maintaining the boundaries between oral and dental ectodermal cells. Implantation of beads soaked in Shh protein into Wnt-7b-infected explants resulted in complete rescue of tooth development, confirming that the repressive action of Wnt-7b specifically affects Shh signaling.