BackgroundSaturated brines are extreme environments of low diversity. Salinibacter ruber is the only bacterium that inhabits this environment in significant numbers. In order to establish the extent of genetic diversity in natural populations of this microbe, the genomic sequence of reference strain DSM 13855 was compared to metagenomic fragments recovered from climax saltern crystallizers and obtained with 454 sequencing technology. This kind of analysis reveals the presence of metagenomic islands, i.e. highly variable regions among the different lineages in the population.ResultsThree regions of the sequenced isolate were scarcely represented in the metagenome thus appearing to vary among co-occurring S. ruber cells. These metagenomic islands showed evidence of extensive genomic corruption with atypically low GC content, low coding density, high numbers of pseudogenes and short hypothetical proteins. A detailed analysis of island gene content showed that the genes in metagenomic island 1 code for cell surface polysaccharides. The strain-specific genes of metagenomic island 2 were found to be involved in biosynthesis of cell wall polysaccharide components. Finally, metagenomic island 3 was rich in DNA related enzymes.ConclusionThe genomic organisation of S. ruber variable genomic regions showed a number of convergences with genomic islands of marine microbes studied, being largely involved in variable cell surface traits. This variation at the level of cell envelopes in an environment devoid of grazing pressure probably reflects a global strategy of bacteria to escape phage predation.

We have created a structure-selectivity database (AMPad) of frog-derived, helical antimicrobial peptides (AMPs), in which the selectivity was determined as a therapeutic index (TI), and then used the novel concept of sequence moments to study the lengthwise asymmetry of physicochemical peptide properties. We found that the cosine of the angle between two sequence moments obtained with different hydrophobicity scales, defined as the D-descriptor, identifies highly selective peptide antibiotics. We could then use this descriptor to predict TI changes after point mutations in known AMPs, and to aid the prediction of TI for de novo designed AMPs. In combination with an amino acid selectivity index, a motif regularity index and other statistical rules extracted from AMPad, the D-descriptor enabled construction of the AMP-Designer algorithm. A 23 residue, glycine-rich, peptide suggested by the algorithm was synthesized and the activity and selectivity tested. This peptide, adepantin 1, is less than 50% identical to any other AMP, has a potent antibacterial activity against the reference organism, E. coli, and has a significantly greater selectivity (TI > 200) than the best AMP present in the AMPad database (TI = 125).

Number of hemodialysis patients each day is increasing. The quality of their lives is largely determined by the quality of hemodialysis treatment. One of the most important factors is the type of applied blood approach. The type of blood approach in the most case is artery venous fistula, permanent, temporary catheters, grafts. Any complications of blood strand approach inevitably leads to lower quality of hemodialysis treatment which is connected with not adequate dialysis and poorer general state of patients. Our research was carried out as a prospective study, for the period of 36 months. In the study were included 31 patients, which are on chronic haemodialysis treatment. During this study, we are followed all complications, which occurred at temporary, and permanent tunneled haemodialysis catheters. Complications have occurred in terms of thrombotic problems, low blood flow, occurrence of infection. All patients are divided in two groups, 16 patients with permanent and 15 patients with temporary catheters. In the course of the study was analyzed blood flow and dialysis adequacy (Kt/Vdp) as well as complications and results was compared with randomly selected 16 patients who haemodialysis treatment performed by artery venous fistula (AVF). Two patients were lost to further follow-up to the end of the study. 26 patients at the end of the study had functional catheters, while in the case of 3 patients the catheter was removed. Infection was found in 10 patients while thrombotic complications were observed in 27 cases regardless of catheter type. Mean blood flow in patients with permanent catheter was significantly higher (296,9+/-28,45 cm3/min) compared to patients with temporary catheter (226,3+/-39,8 cm3/min) (p<0,001). Kt/Vdp delivered was 1,22+/-0,15 on patients with permanent catheter and 1,30+/-0,18 for artery venous fistula (AVF) access respectively. The loss of dialysis efficacy using catheters was estimated at 6%. However, in all cases Kt/Vdp values remained above the recommended values (Kt/Vdp > or = 1,2).

UNLABELLED Delayed kidney graft function and acute rejection in the early post-transplant period affect both short and long-term allograft survival. Allograft rejection, as an inflammatory state, results in increased erythropoietin resistance, which leads to decreased haemoglobin (Hb) level. We conducted this study to evaluate whether inflammation in the early post-transplant period could predict later anemia.This is a retrospective cohort study based on the analysis of 64 existing clinical records. PREDICTOR White blood cells (WBC) count obtained by the end of the first week post-transplant (W1). Covariates: Donor's age, recipient's age and sex. OUTCOME Anemia identified at 12 months (M12) post engraftment. Median WBC count at W1 was 9,5 x103/microL (5th - 95th percentile 5,2 x103/microL -17,8 x103/microL). Mean Hb values at M12 were 129,9 +/- 20,3 g/L, in males 136,2 +/- 20,1 g/L and in females 119,4 +/- 16,2 g/L. The significant correlation was found between WBC at W1 and Hb at M12. Pearson coefficient of correlation r was -0,26, and 95% confidence interval (CI) for r was -0,47 to -0,015 (p=0,03). Univariate logistic regression showed significant association between WBC at W1 and Hb at M12 (OR 1,20; 95% CI 1,04 to 1,39, p=0,01). After the adjustment for donor's and recipient's age by transplantation and recipient's sex, multiple regression showed that WBC count remained predictive of anemia at M12 (OR 1,17; 95% CI 1,01 to 1,36, p=0,03). Early post-transplant inflammatory response predicts later anemia in kidney transplant recipients. An increase in WBC count in the first week post-transplant by 109/L increases the risk for anemia after twelve months by 17%.

Abstract 887 CLL B-cells depend on various signals from the microenvironment for survival and proliferation. Among these, antigenic stimuli that are propagated through the B-cell receptor (BCR) are considered particularly important for the development and progression of CLL, suggesting that the BCR signaling pathway could be an important target for therapeutic intervention. We have previously characterized some of the critical components of the signaling pathway downstream of the BCR in CLL B cells and identified the protein tyrosine kinase Syk as a promising therapeutic target. In a recent study we showed that CLL B-cells frequently have increased basal/constitutive Syk activity and are moderately sensitive to the cytotoxic effect of the selective Syk inhibitor R406 [Gobessi et al , Leukemia 2009]. More importantly, the survival signal induced by sustained BCR engagement was completely abolished by R406, suggesting that this compound may exert an even greater effect in vivo by inhibiting antigen-dependent Syk activation. We have now tested this possibility in the Eμ-TCL1 transgenic mouse model of CLL. Aged Eμ-TCL1 mice develop CD5+ B-cell leukemias that, similar to aggressive human CLL, show features of an antigen-driven process, including expression of stereotyped BCRs and reactivity with common autoantigens and microbial agents [Yan et al , Proc Natl Acad Sci USA 2006]. For our experiments we used a TCL1 leukemia (TCL1-002) that does not grow in vitro , but can be propagated in syngeneic recipients in vivo . TCL1-002 cells express an unmutated stereotyped BCR encoded by the VH12/VK4 combination, which reacts with phosphatidylcholine, an autoantigen exposed on the surface of senescent erythrocytes. In vitro experiments showed that R406 is not cytotoxic for TCL1-002 cells, although it completely inhibited both the basal and BCR-induced activation of signaling pathways downstream of Syk. The absence of a direct cytotoxic effect provided a unique opportunity to investigate whether inhibition of BCR signaling will affect leukemia growth in vivo . For this purpose, 1×10 7 TCL1-002 cells were injected intraperitoneally in 18 syngeneic mouse recipients. Three days later treatment was started in 8 mice with R788, which is the water-soluble prodrug of R406, at a daily dose of 80mg/kg during 18 consecutive days. Because of the rapid clearance of the drug (serum half-life 6 /ml, range 12-300×10 6 /ml), whereas all R788-treated mice showed normal WBC numbers (median 6×10 6 /ml, range 3-8×10 6 /ml, P 50×10 6 /ml). Whereas all mice from the control group (n=9) died between 6 and 18 days from the beginning of therapy, 4 out of 9 mice from the R788 group survived for more than 33 days. The mechanism of R788 activity was primarily related to inhibition of leukemic cell proliferation, as evidenced by a substantial decrease in the percentage of Ki67-positive cells after 7 days of treatment (30% before, 5% after therapy, P To investigate whether R788 will also be effective against other TCL1 tumors we treated five TCL1 mice with preleukemic mono- or oligoclonal B-cell expansions during a four week period. R788 reduced the percentage of CD5+/B220+ cells in 2 cases, whereas in 2 other cases the percentage increased. Interestingly, the pattern of clonal Ig gene rearrangements changed during therapy, suggesting that only certain TCL1 clones are sensitive to R788 treatment. In summary, this study shows that R788 can effectively inhibit the growth of certain TCL1 tumors and provides the first in vivo experimental evidence suggesting that inhibition of antigen-dependent BCR signaling could be an effective therapeutic approach in CLL. Disclosures: No relevant conflicts of interest to declare.

Due to heightened risk for thromboembolic complications, nonvalvular atrial fibrillation (NVAF) presents an absolute indication for long-term oral anticoagulation therapy. This was an observational, analytical, randomised, one-year clinical study, conducted in the Blood Transfusion Institute Sarajevo, Bosnia & Herzegovina. The aim of this study was to present the oral anticoagulation treatment in terms of International normalised ratio (INR) monitoring and warfarin/acenocoumarol dose titration in 117 patients with NVAF. INR values, the doses of warfarin and acenocoumarol, as well as the tendency and adequacy of their changes were monitored. Percentages of the therapeutic INR values were 51,77% and 53,62%, subtherapeutic 42,84% and 35,86%, and supratherapeutic 5,39% and 10,53% for the warfarin and acenocoumarol treatment, respectively. The average total weekly doses (TWD) which most frequently achieved the therapeutic INR values were 27,89+/-12,34 mg and 20,44+/-9,94 mg, for warfarin and acenocoumarol, respectively. The dose changes with the INR values 1,7 or lower/3,3 or higher were omitted in 13,46% and 15,63%, and with the INR values 1,8-3,2 were noted in 8,62% and 13,48% of all the check-up visits in the warfarin and acenocoumarol group, respectively. The annual dose changes were noted in 24,65% and 31,41%, and the daily dose changes in 74,43% and 73,36% of all the check-up visits of warfarin and acenocoumarol group, respectively. We can conclude that the management of the oral anticoagulation treatment in our country is in accordance with the relevant recommendations, but with the present tendency toward underdosing and unnecessary frequent dose changing.