Dual gene activation and knockout screen reveals directional dependencies in genetic networks.

Understanding the direction of information flow is essential for characterizing how genetic networks affect phenotypes. However, methods to find genetic interactions largely fail to reveal directional dependencies. We combine two orthogonal Cas9 proteins from Streptococcus pyogenes and Staphylococcus aureus to carry out a dual screen in which one gene is activated while a second gene is deleted in the same cell. We analyze the quantitative effects of activation and knockout to calculate genetic interaction and directionality scores for each gene pair. Based on the results from over 100,000 perturbed gene pairs, we reconstruct a directional dependency network for human K562 leukemia cells and demonstrate how our approach allows the determination of directionality in activating genetic interactions. Our interaction network connects previously uncharacterized genes to well-studied pathways and identifies targets relevant for therapeutic intervention

Defining operational strengths and gaps relevant to post licensure Group B Streptococcus vaccine effectiveness studies: an expert stakeholder evaluation of the United Kingdom and Uganda

A future Group B Streptococcal (GBS) vaccine for pregnant women to protect neonates is likely to be licensed based on evidence of vaccine induced protective antibody levels. Post licensure surveillance to monitor the impact of any future vaccine on GBS disease therefore needs to be clearly defined (in both high and low income settings). A priority research gap is understanding health system preparedness for a GBS vaccine evaluation This expert stakeholder evaluation aimed to describe the UK and Uganda's operational strengths and gaps relevant to post-licensure GBS vaccine studies

Effects of different leukocyte subpopulations and flow conditions on leukocyte accumulation during reperfusion

Background/Aims: The study examined the interdependent effects of shear stress and different leukocyte subpopulations on endothelial cell activation and cell interactions during low flow and reperfusion. Methods: Human umbilical venous endothelial cells were perfused with either neutrophils or monocytes at different shear stress (2-0.25 dyn/cm 2) and adhesion was quantified by microscopy. Effects of adherent neutrophils and monocytes on endothelial cell adhesion molecule expression were analyzed by flow cytometry after 4-hour static coincubation. After coincubation, the cocultures were reperfused with labeled neutrophils at 2 dyn/cm 2 and their adhesion was quantified selectively. For the control, endothelium monocultures with and without lipopolysaccharide activation were used. Results: At 2 dyn/cm 2, adhesion did not exceed baseline levels on nonactivated endothelium. Decreasing shear stress to 0.25 dyn/cm 2 largely increased the adhesion of both leukocyte subpopulations, similar to the effect of lipopolysaccharide at 2 dyn/cm 2. However, only adherent monocytes increased adhesion molecule expression, whereas neutrophils had no effect. As a functional consequence, adherent monocytes largely increased neutrophil adhesion during reperfusion, whereas adherent neutrophils did not. Conclusion: Compromised shear stress is an autonomous trigger of leukocyte adhesion even in the absence of additional activators. Exceeding this immediate effect, adherent monocytes induce further endothelial activation and enhance further neutrophil adhesion during reperfusion. Copyrigh

Recall and decay of consent information among parents of infants participating in a randomized controlled clinical trial using an audio-visual tool in The Gambia.

Communicating essential research information to low literacy research participants in Africa is highly challenging, since this population is vulnerable to poor comprehension of consent information. Several supportive materials have been developed to aid participant comprehension in these settings. Within the framework of a pneumococcal vaccine trial in The Gambia, we evaluated the recall and decay of consent information during the trial which used an audio-visual tool called 'Speaking Book', to foster comprehension among parents of participating infants. The Speaking Book was developed in the 2 most widely spoken local languages. Four-hundred and 9 parents of trial infants gave consent to participate in this nested study and were included in the baseline assessment of their knowledge about trial participation. An additional assessment was conducted approximately 90 d later, following completion of the clinical trial protocol. All parents received a Speaking Book at the start of the trial. Trial knowledge was already high at the baseline assessment with no differences related to socio-economic status or education. Knowledge of key trial information was retained at the completion of the study follow-up. The Speaking Book (SB) was well received by the study participants. We hypothesize that the SB may have contributed to the retention of information over the trial follow-up. Further studies evaluating the impact of this innovative tool are thus warranted

The burden of viral respiratory infections in young children in low-resource settings.

No abstract availble

Serological Protection 5-6 Years Post Vaccination Against Yellow Fever in African Infants Vaccinated in Routine Programmes.

Introduction: Although effective live attenuated yellow fever (YF) vaccines have been available for over 9 decades sporadic outbreaks continue to occur in endemic regions. These may be linked to several factors including epidemiological factors such as vector and intermediate host distribution or vaccine coverage and efficacy. The World Health Organization's research priorities include gathering systematic evidence around the potential need for booster vaccination with YF vaccine whether this follows full or fractional doses in children. Knowledge on the longevity of response to YF vaccine and the implications of this response needs to be consolidated to guide future vaccination policy. Methods: We measured anti-YF IgG by microneutralization assay in a group of 481 African infants who had received YF vaccine as part of routine EPI programmes, to explore serological protection from YF 5-6 years post YF vaccination, as well as the effect of co variates. Findings: Notably, 22.2% of the cohort had undetectable antibody concentrations, with another 7.5% revealing concentrations below the threshold of seropositivity of 0.5 IU/mL. Sex, season, country and time since vaccination did not affect the longevity of antibody concentration or having antibody concentrations above a defined threshold. Conclusion: Roughly 30% of children in this cohort did not demonstrate anti-yellow fever antibody concentrations above the defined threshold of protection, with 20% having no demonstrable antibody. Knowledge on the longevity of response to YF vaccine and the implications needs to be consolidated to guide future vaccination policy

Autism in the Faroe Islands: diagnostic stability from childhood to early adult life

Childhood autism or autism spectrum disorder (ASD) has been regarded as one of the most stable diagnostic categories applied to young children with psychiatric/developmental disorders. The stability over time of a diagnosis of ASD is theoretically interesting and important for various diagnostic and clinical reasons. We studied the diagnostic stability of ASD from childhood to early adulthood in the Faroe Islands: a total school age population sample (8–17-year-olds) was screened and diagnostically assessed for AD in 2002 and 2009. This paper compares both independent clinical diagnosis and Diagnostic Interview for Social and Communication Disorders (DISCO) algorithm diagnosis at two time points, separated by seven years. The stability of clinical ASD diagnosis was perfect for AD, good for “atypical autism”/PDD-NOS, and less than perfect for Asperger syndrome (AS). Stability of the DISCO algorithm subcategory diagnoses was more variable but still good for AD. Both systems showed excellent stability over the seven-year period for “any ASD” diagnosis, although a number of clear cases had been missed at the original screening in 2002. The findings support the notion that subcategories of ASD should be collapsed into one overarching diagnostic entity with subgrouping achieved on other “non-autism” variables, such as IQ and language levels and overall adaptive functioning

Immunogenic Mycobacterium africanum Strains Associated with Ongoing Transmission in The Gambia

In West Africa, Mycobacterium tuberculosis strains co-circulate with M. africanum, and both pathogens cause pulmonary tuberculosis in humans. Given recent findings that M. tuberculosis T-cell epitopes are hyperconserved, we hypothesized that more immunogenic strains have increased capacity to spread within the human host population. We investigated the relationship between the composition of the mycobacterial population in The Gambia, as measured by spoligotype analysis, and the immunogenicity of these strains as measured by purified protein derivative-induced interferon-γ release in ELISPOT assays of peripheral blood mononuclear cells. We found a positive correlation between strains with superior spreading capacity and their relative immunogenicity. Although our observation is true for M. tuberculosis and M. africanum strains, the association was especially pronounced in 1 M. africanum sublineage, characterized by spoligotype shared international type 181, which is responsible for 20% of all tuberculosis cases in the region and therefore poses a major public health threat in The Gambia

Considerations for post-licensure group B streptococcus vaccine effectiveness studies.

Post-licensure studies of a Group B streptococcal vaccines for pregnant women in low and middle-income countries will require investment in electronic health records