effect of reduced bacterial dilution on human amniotic membrane antibacterial activity, in vitro

The human amniotic membrane is the inner most layer of placenta and has antimicrobial effect, due to the presence of human beta-defensins and elafins. The purpose of this study is to investigate the effect of dilution reduction of 0.5 McFarland prepared from standard bacterial strains of Salmonella enterica BAA-708, Escherichia coli ATCC25922, Pseudomonas aeruginosa ATCC27853, Klebsiella pneumoniae ATCC7881, and Enterococcus faecalis ATCC29212 on antibacterial effect of human amniotic membranes in vitro. Amniotic membranes were obtained from the bank of organ transplantation in Imam Khomeini hospital, of women with elective cesarean section whose HIV, HBV, HCV and VDRL serological tests were negative. They were cut to 1.5x1.5 cm pieces. Then 0.5 McFarland suspensions of 1.5x10[8], 0.5x10[7] and 1.5x10[6] dilutions were prepared from bacteria which then were spread on Mueller Hinton medium agar and a piece of membrane was put in the center of each plate. After 24 hours incubation at 37[degree]C, the results were observed. In 0.5 McFarland standard dilution an inhibition zone was created in three standard strains of Pseudomonas aeruginosa, Escherichia coli, and Salmonella enterica unlike the other two strains. There was no change in the above results with two other dilutions and inhibition zone of sensitive strains was not created. Dilution reduction of microbial strains does not affect the antibacterial impact of amniotic membrane and dilution reduction does not yield to a false positive response and the conversion of resistant to sensitive strains

[Determination of genotype variation of Escherichia coli in well water of Tehran's parks by multiplex PCR]

Background and Aim: Water plays a major role in public health and the contaminated water has direct effect on human health. E.coli is an indicator of water pollution; different strains of E.coli such as ETEC, EHEC, EIEC and EPEC can cause diarrhea in children. The aim of this study is to investigate the contamination rate of well water of Tehran's parks, and pathotyping E.coli strains which cause diarrhea

Materials and Methods: 156 well water samples from five different geographical parts of Tehran [north, south, east, west, and the centre] were collected aseptically. The collected samples were transferred to the laboratory in microbiology section, School of Public Health, for membrane filtrations and patotyping

Results: 90 out of 156 samples [54/5%] were contaminated with E.coli. The samples from south part were more contaminated compared to others. Out of 90 isolated E.coli only 67 were DEC, in which 42 [62.7%] were detected as EPEC, 12 [17.9%] as STEC or ETEC, 9 [13.4%] as EIEC and 4 [6%] as ETEC by PCR method

Conclusion: Presence of different biotypes of E.coli in well water of parks can be dangerous, especially for children; thus, placing warning signs and educating people in this regard should be taken seriously

[Determination of gamma-globin induction levels by different concentrations of hydroxyurea in K 562 cell lines for beta thalassemia treatment

Hydroxyurea [HU] is currently used for beta thalassemia treatment through induction of fetal gamma-globin, In this study, effects of different concentrations of hydroxyurea on induction of gamma-globin gene in K562 cells, and inhibitory effect of siRNA against candidate gene which may be involved in HU mediated gamma-globin induction were assessed. In this eperimantal study, K562 cells were treated by different concentrations of HU [0, 50, 100 and 200 microM]. siRNA against candidate gene in HU mediated gamma-globin gene induction was transfected to K562 cells using lipofectamine 2000. The level of gammal-globin gene induction and inhibition were determined by quantitavie real-time PCR. There were 1.75-, 2.45- and 2.55- fold inductions in gamma-globin gene using 50, 100 and 200 microM HU, respectively. There has been 79.5% down regulation on candidate gene in siRNA transfected K562 cells. This study showed that gamma-globin induction in 100 microM HU is similar to 200 micro M HU treated K562 cells. There was also efficient inhibitory effect on candidate gene which may be involved in HU mediated gamma-globin induction

[Assessing the levels of cAMP response element binding protein 1 [CREB1] after siRNA mediated knockdown in K562 cells]

CREB1 is an important downstream protein for many signaling pathways. By designing efficient siRNAs against CREB1, it may be possible to assess the role of molecules involved in signaling pathways in different cell types. In this research the efficiency of CREB1 knockdown by two different siRNAs in K562 cells has been studied. siRNAs have been designed according to the criteria suggested by Reynolds et al. K562 cells were transfected by siRNA using Lipofectamine 2000. The efficiency of CREB knockdown has been assessed by quantitative relative Real-time PCR. Our results have shown that only one of the siRNAs has a high level of inhibitory effect on CREB1 gene expression. The expression of CREB1 by this siRNA was knocked-down by 87% in K562 cells. In this research, although two siRNAs were designed according to the Reynolds et al. criteria, only one showed an inhibitory effect. Reasons other than the aforementioned criteria may be involved in effectiveness of siRNAs