The mannose receptor mediates uptake of pathogenic and nonpathogenic mycobacteria and bypasses bactericidal responses in human macrophages

The mannose receptor (MR) is involved in the phagocytosis of pathogenic microorganisms. Here we investigated its role in the bactericidal functions of human monocyte-derived macrophages (MDMs), using (i) trimannoside-bovine serum albumin (BSA)-coated latex beads and zymosan as particulate ligands of the MR, and (ii) mannan and mannose-BSA as soluble ligands. We show that phagocytosis of mannosylated latex beads did not elicit the production of O2-. Zymosan, which is composed of alpha-mannan and beta-glucan, was internalized by the MR and a beta-glucan receptor, but the production of O2- was triggered only by phagocytosis through the beta-glucan receptor. Activation and translocation of Hck, a Src family tyrosine kinase located on lysosomes, has previously been used as a marker of fusion between lysosomes and phagosomes in human neutrophils. In MDMs, Hck was activated and recruited to phagosomes containing zymosan later than LAMP-1 and CD63. Phagosomes containing mannosylated latex beads fused with LAMP-1 and CD63 vesicles but not with the Hck compartment, and the kinase was not activated. We also demonstrate that the MR was unable to distinguish between nonpathogenic and pathogenic mycobacteria, as they were internalized at similar rates by this receptor, indicating that this route of entry cannot be considered as a differential determinant of the intracellular fate of mycobacteria. In conclusion, MR-dependent phagocytosis is coupled neither to the activation of NADPH oxidase nor to the maturation of phagosomes until fusion with the Hck compartment and therefore constitutes a safe portal of entry for microorganisms.     

Armed conflict and children's rights

Comments on the article by V. Murphy-Berman and V. Weisz (1996) in which some of the significant challenges and issues in implementing the United Nations Convention on the Rights of the Child (CRC) are discussed. The author believes that though the article was insightful, it overlooked the impact of armed conflict, one of the most profound sources of abuse of children's human rights worldwide. Some of the points made in an article by G. Machel (1996) are restated including the number of children soldiers and the physical, emotional, and psychological abuse they endure. The author goes on to mention other issues including parentless refugees, the dangers of land mines during and after the war, and the effects of sanctions on children. The author believes that intercultural differences and political issues may also hamper the implementation of the CRC. The article concludes with ways in which psychologists can help and the need to ratify the CRC. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Singularity in Green's function and its numerical evaluation

The free-space scalar Green's functionghas anR^{-1}singularity, whereRis the distance between the source and observation points. The second derivatives ofghaveR^{-3}singularities, which are not generally integrable over a volume. The derivatives ofgare treated as generalized functions in the manner described by Gel'fand and Shilov, and a new formula is derived that regularizes a divergent convolution integral involving the second derivatives ofg. When the formula is used in the dyadic Green's function formulation for calculating theEfield, all previous results are recovered as special cases. Furthermore, it is demonstrated that the formula is particularly suitable for the numerical evaluation of the field at a source point, because it allows the exclusion of an arbitrary finite region around the singular point from the integration volume. This feature is not shared by any of the previous results on the dyadic Green's function.     

APIC position paper: hepatitis C exposure in the health care setting. Association for Professionals in Infection Control and Epidemiology, Inc

The Association for Professionals in Infection Control and Epidemiology, Inc (APIC), is a multidisciplinary, voluntary, international organization of professionals who practice infection control and the application of epidemiology in all health settings. APIC is an international leader in prevention and control of infection transmission.