Human subcortical brain asymmetries in 15,847 people worldwide reveal effects of age and sex

The two hemispheres of the human brain differ functionally and structurally. Despite over a century of research, the extent to which brain asymmetry is influenced by sex, handedness, age, and genetic factors is still controversial. Here we present the largest ever analysis of subcortical brain asymmetries, in a harmonized multi-site study using meta-analysis methods. Volumetric asymmetry of seven subcortical structures was assessed in 15,847 MRI scans from 52 datasets worldwide. There were sex differences in the asymmetry of the globus pallidus and putamen. Heritability estimates, derived from 1170 subjects belonging to 71 extended pedigrees, revealed that additive genetic factors influenced the asymmetry of these two structures and that of the hippocampus and thalamus. Handedness had no detectable effect on subcortical asymmetries, even in this unprecedented sample size, but the asymmetry of the putamen varied with age. Genetic drivers of asymmetry in the hippocampus, thalamus and basal ganglia may affect variability in human cognition, including susceptibility to psychiatric disorders

Antimicrobial efficacy of Hibiscus Fuscus garcke aqueous and ethanol extracts on tooth root canal microorganisms

Objective: To determine the antimicrobial efficacy of Hibiscus fucus extracts against six root canal microorganisms. Design: In-vitro analytical study. Setting: Department of Medical Microbiology, University of Nairobi. Material and Methods: Hibiscus fuscus twigs were collected, dried and ground into coarse powder which was macerated in sterile distilled water and 80% ethanol. The aqueous filtrates were lipolyzed, while the ethanol filtrates were reduced, and oven dried into powder. Tenfold liquid microdilution of 50 mg/ml Hibiscus fuscus extracts against pure strains of Enterococcus faecalis, Streptococcus mutans, Staphylococcus aureus, Fusobacterium nucleatum, Lactobacillus acidophilus and Candida albicans were incubated for 24 and 48 hours. Sodium hypochlorite 5.25% and 2% Chlorhexidine gluconate were the controls. Outcome measures: Percentage growth inhibition measured by changes in growth of microorganism cultures exposed to Hibiscus fuscus extracts. One-way analysis of variance and Tukey’s HSD test were used to test for any differences. Results: Fifty mg/ml Hibiscus fuscus aqueous extracts attained 122.01% ± 22.89, at 95% CI [108.79, 135] and (105.73% ± 7.64, at 95% CI [101.32,110.14] growth inhibition against Enterococcus faecalis and Fusobacterium nucleatum for 24 hours incubation similar to those obtained with 5.25% Sodium hypochlorite, and 2% Chlorhexidine gluconate at p=0.899947 (Tukey’s HSD). Other bacteria tested and Candida albicans showed resistance Conclusion: Fifty mg/ml Hibiscus fuscus aqueous extract showed bactericidal efficacy against E. faecalis (ATCC® 29212 ™), and F. nucleatum (ATCC® 25586™) comparable to 5.25% Sodium hypochlorite and 2% Chlorhexidine gluconate. Investigation to test pure Hibiscus fuscus extracts as a potential source of root canal irrigant is needed

Constraints on Neighbourhood Activism: Experiences with Services Upgrading in Nakuru, Kenya

This paper tries to explain why community action and partnering in services upgrading in Nakuru, Kenya, has only produced very modest results. Although inhabitants feel connected to their neighbourhood, they do not automatically translate their attachment into concrete action to improve liveability. This is due to a range of reasons, including competing loyalties of citizens, antagonism between local leaders, pervasive influence of patronage and cronyism, chronic weaknesses of local government and tendencies of CBOs to become more exclusionary. These findings somewhat temper the general optimism in the Habitat literature about the potentials of communities in spurring local development processes. Nakuru is a good place to investigate this issue since it is often portrayed as an example of best practice in local-government—community interaction, especially because of its commitment to the LA-21 process

Annual cyclicity in high-resolution stable carbon and oxygen isotope ratios in the wood of the mangrove tree Rhizophora mucronata

In the present study, the high-resolution stable carbon (13C/12C) and oxygen (18O/16O) isotope ratio profiles in the wood of the mangrove Rhizophora mucronata Lam., a tropical tree species lacking distinct growth rings, were investigated. Variations of both isotope ratios revealed a remarkable annual cyclicity with lowest values occurring at the latewood/earlywood boundary (April–May) and highest values during the transition from earlywood to latewood (October–November). Based on the current knowledge of the physiology of this mangrove species, as well as on the current literature available on high-resolution profiles of stable isotope ratios in tree rings, possible driving forces responsible for this seasonal pattern are discussed. The annual cyclicity, together with a conspicuous isotope pattern appearing in the El-Niño year 1997, promises great potential for tropical dendrochronology

Human subcortical brain asymmetries in 15,847 people worldwide reveal effects of age and sex

The two hemispheres of the human brain differ functionally and structurally. Despite over a century of research, the extent to which brain asymmetry is influenced by sex, handedness, age, and genetic factors is still controversial. Here we present the largest ever analysis of subcortical brain asymmetries, in a harmonized multi-site study using meta-analysis methods. Volumetric asymmetry of seven subcortical structures was assessed in 15,847 MRI scans from 52 dataset worldwide. There were sex differences in the asymmetry of the globus pallidus and putamen. Heritability estimates, derived from 1170 subjects belonging to 71 extended pedigrees, revealed that additive genetic factors influenced the asymmetry of these two structures and that of the hippocampus and thalamus. Handedness had no detectable effect on subcortical asymmetries, even in this unprecedented sample size, but the asymmetry of the putamen varied with age. Genetic drivers of asymmetry in the hippocampus, thalamus and basal ganglia may affect variability in human cognition, including susceptibility to psychiatric disorders

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

The past 2 years, during which waves of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants swept the globe, have starkly highlighted health disparities across nations. Tegally et al. show how the coordinated efforts of talented African scientists have in a short time made great contributions to pandemic surveillance and data gathering. Their efforts and initiatives have provided early warning that has likely benefited wealthier countries more than their own. Genomic surveillance identified the emergence of the highly transmissible Beta and Omicron variants and now the appearance of Omicron sublineages in Africa. However, it is imperative that technology transfer for diagnostics and vaccines, as well the logistic wherewithal to produce and deploy them, match the data-gathering effort

Human subcortical brain asymmetries in 15,847 people worldwide reveal effects of age and sex

The online version of this article (doi:10.1007/s11682-016-9629-z) contains supplementary material, which is available to authorized users