The Influence of Gestational Age on the Loss of Maternal Measles Antibodies in Newborn Infants in North-Eastern Nigeria: A Call for a Review of Measles Immunization Schedule

Background: Maternal measles antibodies (MMA) are actively transferred in mother-infant pairs during third trimester of pregnancy. Gestational age (GA) affects the levels of MMA such that longer GA may result in infants starting out with high levels of MMA.Objective: To determine the influence of GA on the loss of MMA in newborn infants in North-Eastern Nigeria.Method: A prospective study was conducted on newborn infants at Maiduguri; sera were collected at birth and at six months of age. Enzyme linked immunosorbent assay (ELISA) was used to measure MMA while GA was determined using the last menstrual period, ultrasound scan reports and the Dubowitz criteria.Results: Seventy eight newborn infants were enrolled. Seventeen (89.5 %) preterm, 43 (95.6 %) term and 14 (100 %) postterm had protective levels of MMA at birth. Two (10.5 %) preterm, nine (20.0%) term and two (14.3 %) postterm had protective MMA at six months of age. Comparison of mean MMA at birth and at six months of age was significant (p = 0.005), however, it was independent of GA of the newborn infants.Conclusion: Significant decline of mean MMA levels was seen in these infants at six months of age, which was independent of their GA. These infants may be prone to measles at an earlier age (less than six months). Therefore, the current recommendation of measles immunization to infants at nine months of age may require reconsideration

Mapping recent information behavior research: an analysis of co-authorship and cocitation networks

There has been an increase in research published on information behavior in recent years, and this has been accompanied by an increase in its diversity and interaction with other fields, particularly information retrieval (HR). The aims of this study are to determine which researchers have contributed to producing the current body of knowledge on this subject, and to describe its intellectual basis. A bibliometric and network analysis was applied to authorship and co-authorship as well as citation and co-citation. According to these analyses, there is a small number of authors who can be considered to be the most productive and who publish regularly, and a large number of transient ones. Other findings reveal a marked predominance of theoretical works, some examples of qualitative methodology that originate in other areas of social science, and a high incidence of research focused on the user interaction with information retrieval systems and the information behavior of doctors

RNA Interference Screen Identifies Abl Kinase and PDGFR Signaling in Chlamydia trachomatis Entry

To elucidate the mechanisms involved in early events in Chlamydia trachomatis infection, we conducted a large scale unbiased RNA interference screen in Drosophila melanogaster S2 cells. This allowed identification of candidate host factors in a simple non-redundant, genetically tractable system. From a library of 7,216 double stranded RNAs (dsRNA), we identified,226 host genes, including two tyrosine kinases, Abelson (Abl) kinase and PDGF- and VEGF-receptor related (Pvr), a homolog of the Platelet-derived growth factor receptor (PDGFR). We further examined the role of these two kinases in C. trachomatis binding and internalization into mammalian cells. Both kinases are phosphorylated upon infection and recruited to the site of bacterial attachment, but their roles in the infectious process are distinct. We provide evidence that PDGFRb may function as a receptor, as inhibition of PDGFRb by RNA interference or by PDGFRb neutralizing antibodies significantly reduces bacterial binding, whereas depletion of Abl kinase has no effect on binding. Bacterial internalization can occur through activation of PDGFRb or through independent activation of Abl kinase, culminating in phosphorylation of the Rac guanine nucleotide exchange factor (GEF), Vav2, and two actin nucleators, WAVE2 and Cortactin. Finally, we show that TARP, a bacterial type III secreted actin nucleator implicated in entry, is a target of Abl kinase. Together, our results demonstrate that PDGFRb and Abl kinases function redundantly to promote efficient uptake of this obligate intracellula