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Background and purpose: Ëmbryonic stem cells (ËSÇ) can be produced by culturing blastocytes inner cell mass in a proper condition. ËSÇ are used as research tool in producing transgenic animals and in the study of embryo deyelopment. Produced blastocytes can be vitrified and used in appropriate time. Âim of this study was to determine the mean number and survival rate of vitrified ÏÇM, in order to use vitrified embryos in production of stem cells.
Materials and methods : Âfter in vitro maturation and fertilization of immature bovine oocytes, embryos were co-cultured in Hams’F10 medium over Vero cells for 7 or 8 days at 30oc and 5% ÇÔ2. 500 blastocytes were selected and divided into two groups case and control. The blastocytes of the case group were vitrified (Ëthylene glycol 40%, Ficoll 18% and 0.3M sucrose). Âfter thawing, embryos were cultured for 24hr and the expanded embryos, along with the blastocytes in the control group were isolated by immunosurgery method. Çell survivals were assessed by trypan blue staining.
Results : The survival rate of ÏÇM cells at the day 7 blastocytes in the control and vitrified groups were 96% and 83% repectively, and the average number of ÏÇM cells were 17.4 ± 3 and 14 ± 2 respectively. The survival rate of ÏÇM cells from day 8th blastocytes in control and vitrified groups were 95% and 82% respectively. Mean number of ÏÇM cells were 18.6±3.
Çonclusion : Survival rate and number of blastocyte inner cell mass in the control and vitrified groups on the day 7 and 8 were significantly different. Ïn vitrified condition the survival rate and number of the cells declines significantly. Therefore it is not recommended to use vitrified blastocytes for production of the embryonic stern cells.

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 Background and purpose: Burn wounds are a good host for infections. Acinetobacter baumannii is an opportunistic bacterium in patients with burn infections. Toxin-antitoxin systems (TA_S) are genetic elements that are essential for antibiotic resistance and biofilm formation in bacteria, including higBA and relBE TA systems. The present study aimed to investigate the frequency of higBA and relBE genes in A. baumannii strains isolated from burn wound infection as well as the association between genetic elements and antibiotic resistance and biofilm formation.
Materials and methods: In this descriptive cross-sectional study, 139 A. baumannii isolates were collected from burn wounds of patients hospitalized in a burn center in Isfahan, Iran. The isolates were identified and confirmed through biochemical and molecular tests. Antibiotic susceptibility testing was performed via disk diffusion method and biofilm production was detected by microtiter plate assay. Presence of higBA and relBE TA system genes was investigated by PCR.
Results: Out of 139 A. baumannii isolates, 114 were multi-drug resistant (MDR) and able to form biofilm. relBE and higBA genes were observed in 94.73% and 8.77% of the isolates, respectively. Significant correlations were found between the presence of relBE and higBA genes and resistance to imipenem and levofloxacin (P<0.05). There were no significant correlations between presence of relBE and higBA genes and biofilm formation (P>0.05).
Conclusion: In this study, the number of MDR A. baumanni strains was significantly higher compared to previous studies and most species had the ability to form biofilms. According to the association between TA genes and antibiotic resistance, further studies are needed on the TA systems.