Enhanced translocation of single DNA molecules through α-hemolysin nanopores by manipulation of internal charge

Both protein and solid-state nanopores are under intense investigation for the analysis of nucleic acids. A crucial advantage of protein nanopores is that site-directed mutagenesis permits precise tuning of their properties. Here, by augmenting the internal positive charge within the α-hemolysin pore and varying its distribution, we increase the frequency of translocation of a 92-nt single-stranded DNA through the pore at +120 mV by ≈10-fold over the wild-type protein and dramatically lower the voltage threshold at which translocation occurs, e.g., by 50 mV for 1 event·s⁻¹·μM⁻¹. Further, events in which DNA enters the pore, but is not immediately translocated, are almost eliminated. These experiments provide a basis for improved nucleic acid analysis with protein nanopores, which might be translated to solid-state nanopores by using chemical surface modification.     

Interleukin-10 and Transforming Growth Factor-β in Early and Late Lesions of Patients with Leishmania major induced Cutaneous Leishmaniasis

Background

Cutaneous leishmaniasis is a neglected parasitic disease, which imposes massive human distress and financial costs to the endemic countries. Better understanding of host immune response to the parasite leads to helpful strategies for disease control. Interleukin (IL)-10 and transforming growth factor (TGF)-β are important immune regulatory cytokines, which appear to develop non-healing forms of leishmaniasis. However, there is little information about the function of IL-10 and TGF-β in old world cutaneous leismaniasis. The aim of this study was to analyze the role of IL-10 and TGF-β in human cutaneous leishmaniasis due to Leishmania major infection.

Methods

Biopsies were obtained from lesions of twenty proven cases of L. major induced cutaneous leishmaniasis. IL-10 and TGF-β positive cells were detected by immunofluorescence staining of frozen sections and compared between two groups of patients with early and late lesions.

Results

The mean percentage of IL-10 positive cells were significantly (P= 0.035) higher in late lesions (0.51±0.24) than early ones (0.15±0.07). Similar results were obtained for TGF-β with mean percentages of 0.16±0.05 and 0.53±0.28 in early and late lesions respectively (P= 0.008).

Conclusion

IL-10 and TGF-β are present in lesions of L. major induced cutaneous leishmaniasis and contribute to the pathogenesis of long lasting disease forms.     

Screening with monoclonal anti-Fy3 to provide blood for phenotype- matched transfusions for patients with sickle cell disease

BACKGROUND: In the United States, there is a shortage of blood group phenotype-matched red cells (RBCs) for patients with sickle cell disease (SCD). A protocol designed to supply phenotype-matched RBCs for these patients by combining the recruitment of African American blood donors and automated testing of RBCs for these patients for the presumptive Fy(a-b-) phenotype using monoclonal anti-Fy3 was evaluated. STUDY DESIGN AND METHODS: African American donors were recruited, to increase the likelihood of phenotype matches in the donor population. Samples of RBCs were tested for the presumptive Fy(a-b-) phenotype by using monoclonal anti-Fy3 and an automated blood typing analyzer. RBCs confirmed to be Fy(a-b-) were retyped for selected Rh, MNS, Kell, Duffy, and Kidd blood system antigens. The extended phenotypes were matched with those of 41 SCD patients requiring transfusions. RESULTS: Of 8323 blood donations during the study, approximately 40 percent (3329) were made by African Americans. Approximately 22 percent (737) of African Americans were identified as Fy(a-b-) by this protocol and 12 percent (410) were phenotype matches for the 41 SCD patients. CONCLUSION: Combining the recruitment of African American blood donors and automated phenotyping using monoclonal anti-Fy3 offers a practical, relatively low-cost strategy for supplying phenotype-matched RBCs for SCD patients. This protocol increases the options for addressing the shortage of phenotype-matched RBCs for SCD patients.