a. masoudi

Heat stress, or hyperthermia, can have a serious effect on chicken performance in poultry industry in many parts of the world. Both genetics and environment play key role in the performance of a chicken and, therefore, it is important to consider both factors in addressing heat stress. On genetics level, genome-wide association studies have become a popular method for studying heat stress in recent years. A population of 202 F2 chickens was reared for 84 days to find genes and genomic regions affecting growth traits and immune system. But, due to unexpected acute increase in temperature at day 83, 182 birds died (case) and 20 birds remained alive (control). At the age of 70 days, blood sample of all birds was collected to extract their DNA, using modified salting out method. All samples were genotyped by a 60 K Single Nucleotide Polymorphism (SNP) chip. Genome-wide association study was carried out by GCTA to identify gene and genomic regions associated with heat stress tolerance. Results indicated a close relationship between 28 SNPs, located on chromosomes 2, 3, 5, 6, 7, 12, 19, 20, and 21 and heat stress tolerance at the level of suggestive significance. Two suggestively significant markers on chromosome 5, namely, GGaluGA273356 and Gga_rs16479429, were located within and 52 Kb downstream of two genes, including MAPKBP1and SPON1, respectively. Gene ontology analysis indicated that the resistance of chickens to acute increase of temperature might be linked to the function of MAPKBP1 and SPON1 genes and their biological pathways. These results will be useful for understanding the molecular mechanisms of SNPs and candidate genes for heat stress tolerance in chickens and provide a basis for increasing genetic resistance in breeding programs.

To evaluate the histopathological changes of the cornea in rabbit corneas after accelerated collagen cross-linking.

Right eyes of 7 adult New Zealand albino rabbits weighing 1.5 to 2.0 kg were studied. Right eyes of all animals were in the treatment group and left eyes were in the control group. The epithelium of all right eyes was removed and was crossed-linked with riboflavin 0.1% solution (10 mg riboflavin-5-phosphate in 10ml 20% dextran-T-500) applied every 3 minutes for 30 minutes, and exposed to UVA (360 nm, 3 mW/cm2) for 10 minutes. All rabbits were humanely euthanized and examined histologically. Apoptosis was evaluated using TUNEL staining.

There was a significant difference in the mean percent of apoptotic cells in the treated and control groups. In both keratocyte and endothelial cells of the treated cornea, the number of apoptotic cells was significantly higher than the control group. In the evaluation of cornea totally (endothelial and keratocyte), the mean percent and standard deviation of apoptotic cells were 18.29 ± 3.2 in right eyes and 6.29 ± 1.7 in left eyes. In the evaluation of apoptosis in keratocytes separately, the mean percent and SD in right eyes were 15.29±2.56 that was significantly higher in comparison with the left eyes 5.71±1.5. The mean and SD of apoptotic endothelial cells in right and left eyes were 2.86±1.07, 0.53±0.43, respectively, that were statically significant (P= 0.026).

Although CXL is a safe procedure to arrest progression in keratoconus disease, due to endothelial cell damage in our study and others, there are some risks for endothelial cell damage and related complications; so, it needs for more studies.

To compare donor lenticule thickness reported by the eye bank with lenticule thickness measured at 6 months after Descemet stripping automated endothelial keratoplasty (DSAEK). This prospective, interventional case series enrolled 30 eyes of 30 patients, who underwent DSAEK, using precut eye bank tissue. Preoperative thickness measurements of the donor lenticules were taken centrally and at pericentral and peripheral graft areas using an anterior segment optical coherence tomography system. The same measurements were repeated 6 months postoperatively. The preoperative and postoperative values were compared, and the relationships between these measurements were investigated, using Pearson correlation coefficients. The mean donor age was 47.7±10.7 years old. The mean preoperative endothelial cell density was 3016.8±361.4 cells/mm2, which decreased to 1644.9±482.0 cells/mm2 postoperatively (P<0.001). The graft thickness of the precut tissue, as reported by the eye bank, was 136.8±24.9 μm at the center, 149.4±27.3 μm at the pericentral area, and 198.4±32.8 μm at the periphery. The corresponding postoperative values were 119.2±29.8 μm (P=0.004), 124.5±34.6 μm (P=0.002), and 156.3±45.4 μm (P<0.001), respectively. The graft thickness measured by the eye bank was significantly associated with that measured in vivo at 6 months at the central (r=0.63; P=0.001) and pericentral (r=0.5; P=0.009) graft area. However, the correlation between preoperative and postoperative peripheral graft thickness was insignificant (P= 0.14). Compared to preoperative values, central, pericentral, and peripheral graft thicknesses were reduced by 10.4%, 14.2%, and 18.4%, respectively, 6 months after DSAEK. Postoperative graft thinning was greater at the periphery compared with the central and pericentral area.

To investigate the rate and agents of contamination in bandage soft contact lenses fitted for the management of persistent corneal epithelial defects and to evaluate potential variables that could influence contamination risk. This prospective comparative case series enrolled 57 consecutive eyes fitted with bandage contact lenses for the treatment of persistent corneal epithelial defects. The lenses were collected at the time of epithelial closure or when it was necessary to exchange contact lenses and were immediately placed in sterile tubes containing an enriched thioglycolate liquid medium. When contamination of the contact lens was detected, the microorganism was cultured in different media and identified based on various tests. All isolates were tested for susceptibility to various antibiotics. Univariate analyses were used to evaluate the influence of different variables on bandage contact lens contamination. Seventeen of the contact lenses (29.8%) were contaminated. The most commonly isolated pathogen was Staphylococcus epidermidis (n=10), followed by Enterobacter cloacae (n=3), Staphylococcus aureus (n=1), Streptococcus viridans (n=1), and Alcaligenes spp. (n=1). One contact lens yielded a mixed infection with Enterobacter cloacae and Candida spp. Infectious keratitis was not observed in any eyes. Correlations between contact lens contamination and investigated variables were statistically non-significant. A significant number of bandage contact lenses used for the management of persistent corneal epithelial defects yielded positive cultures for aerobic bacteria. However, no cases of infectious keratitis were observed. Contamination was independent of different investigated variables, including the duration of contact lens use.