Nonspecific
adsorption of biomolecules to solid surfaces, a process
called biofouling, is a major concern in many biomedical applications.
Great effort has been made in the development of antifouling polymer
coatings that are capable of repelling the nonspecific adsorption
of proteins, cells, and micro-organisms. In this respect, we herein
contribute to understanding the factors that determine which polymer
brush results in the best antifouling coating. To this end, we compared
five different monomers: two sulfobetaines, a carboxybetaine, a phosphocholine,
and a hydroxyl acrylamide. The antifouling coatings were analyzed
using our previously described bead-based method with flow cytometry
as the read-out system. This method allows for the quick and automated
analysis of thousands of beads per second, enabling fast analysis
and good statistics. We report the first direct comparison made between
a sulfobetaine with opposite charges separated by two and three methylene
groups and a carboxybetaine bearing two separating methylene groups.
It was concluded that both the distance between opposite charges and
the nature of the anionic groups have a distinct effect on the antifouling
performance. Phosphocholines and simple hydroxyl acrylamides are not
often compared with the betaines. However, here we found that they
perform equally well or even better, yielding the following overall
antifouling ranking: HPMAA ≥ PCMA-2 ≈ CBMAA-2 > SBMAA-2
> SBMAA-3 ≫ nonmodified beads (HPMAA being the best).
Childhood anemia is a major global health problem resulting from multiple causes. Iron supplementation addresses iron deficiency anemia but is undesirable for other types of anemia and may exacerbate infections. The peptide hormone hepcidin governs iron absorption; hepcidin transcription is mediated by iron, inflammation, and erythropoietic signals. However, the behavior of hepcidin in populations where anemia is prevalent is not well established. We show that hepcidin measurements in 1313 African children from The Gambia and Tanzania (samples taken in 2001 and 2008, respectively) could be used to identify iron deficiency anemia. A retrospective secondary analysis of published data from 25 Gambian children with either postmalarial or nonmalarial anemia demonstrated that hepcidin measurements identified individuals who incorporated >20% oral iron into their erythrocytes. Modeling showed that this sensitivity of hepcidin expression at the population level could potentially enable simple groupings of individuals with anemia into iron-responsive and non-iron-responsive subtypes and hence could guide iron supplementation for those who would most benefit.
BackgroundDuring the inflammatory process, chemokine CXCL8 plays a pivotal role in recruitment of human neutrophilic granulocytes. A diversity of sequences similar to CXCL8 was reported in fish, but their evolutionary relationships and functional homology with their human homolog remain unclear.Principal FindingsWe screened fish genomes to seek for sequences related to CXCL8. A first lineage was retrieved in all teleosts, while a second CXCL8 lineage was found in zebrafish and carp only. An early inflammatory function for both lineages was indicated by several lines of evidence. The induction of carp CXCL8s, CXCb, and CXC receptor-1 and -2 was analyzed after in vitro stimulation of leukocyte subpopulations and in two in vivo inflammation models. Recombinant proteins of carp CXCL8 proteins were produced and showed significant chemotactic activity for carp leukocytes.ConclusionsWhile both carp CXCL8s appear to be functional homologs of mammalian CXCL8, their different induction requirements and kinetics evoke a gene-specific sub-functionalization.
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