Rethinking the dispersal of Homo sapiens out of Africa

Current fossil, genetic, and archeological data indicate that Homo sapiens originated in Africa in the late Middle Pleistocene. By the end of the Late Pleistocene, our species was distributed across every continent except Antarctica, setting the foundations for the subsequent demographic and cultural changes of the Holocene. The intervening processes remain intensely debated and a key theme in hominin evolutionary studies. We review archeological, fossil, environmental, and genetic data to evaluate the current state of knowledge on the dispersal of Homo sapiens out of Africa. The emerging picture of the dispersal process suggests dynamic behavioral variability, complex interactions between populations, and an intricate genetic and cultural legacy. This evolutionary and historical complexity challenges simple narratives and suggests that hybrid models and the testing of explicit hypotheses are required to understand the expansion of Homo sapiens into Eurasia.     

Predominance of distal skin temperature changes at sleep onset across menstrual and circadian phases

Menstrual cycle-associated changes in reproductive hormones affect body temperature in women. We aimed to characterize the interaction between the menstrual, circadian, and scheduled sleep-wake cycles on body temperature regulation. Eight females entered the laboratory during the midfollicular (MF) and midluteal (ML) phases of their menstrual cycle for an ultradian sleep-wake cycle procedure, consisting of 36 cycles of 60-minute wake episodes alternating with 60-minute nap opportunities, in constant bed-rest conditions. Core body temperature (CBT) and distal skin temperature (DT) were recorded and used to calculate a distal-core gradient (DCG). Melatonin, sleep, and subjective sleepiness were also recorded. The circadian variation of DT and DCG was not affected by menstrual phase. DT and DCG showed rapid, large nap episode-dependent increases, whereas CBT showed slower, smaller nap episode-dependent decreases. DCG values were significantly reduced for most of the wake episode in an overall 60-minute wake/60-minute nap cycle during ML compared to MF, but these differences were eliminated at the wake-to-nap lights-out transition. Nap episode-dependent decreases in CBT were further modulated as a function of both circadian and menstrual factors, with nap episode-dependent deceases occurring more prominently during the late afternoon/evening in ML, whereas nap episode-dependent DT and DCG increases were not significantly affected by menstrual phase but only circadian phase. Circadian rhythms of melatonin secretion, DT, and DCG were significantly phase-advanced relative to CBT and sleep propensity rhythms. This study explored how the thermoregulatory system is influenced by an interaction between circadian phase and vigilance state and how this is further modulated by the menstrual cycle. Current results agree with the thermophysiological cascade model of sleep and indicate that despite increased CBT during ML, heat loss mechanisms are maintained at a similar level during nap episodes, which may allow for comparable circadian sleep propensity rhythms between menstrual phases.     

Role of permissive neuraminidase mutations in influenza A/Brisbane/59/2007-like (H1N1) viruses

Neuraminidase (NA) mutations conferring resistance to NA inhibitors were believed to compromise influenza virus fitness. Unexpectedly, an oseltamivir-resistant A/Brisbane/59/2007 (Bris07)-like H1N1 H275Y NA variant emerged in 2007 and completely replaced the wild-type (WT) strain in 2008-2009. The NA of such variant contained additional NA changes (R222Q, V234M and D344N) that potentially counteracted the detrimental effect of the H275Y mutation on viral fitness. Here, we rescued a recombinant Bris07-like WT virus and 4 NA mutants/revertants (H275Y, H275Y/Q222R, H275Y/M234V and H275Y/N344D) and characterized them in vitro and in ferrets. A fluorometric-based NA assay was used to determine Vmax and Km values. Replicative capacities were evaluated by yield assays in ST6Gal1-MDCK cells. Recombinant NA proteins were expressed in 293T cells and surface NA activity was determined. Infectivity and contact transmission experiments were evaluated for the WT, H275Y and H275Y/Q222R recombinants in ferrets. The H275Y mutation did not significantly alter Km and Vmax values compared to WT. The H275Y/N344D mutant had a reduced affinity (Km of 50 vs 12 μM) whereas the H275Y/M234V mutant had a reduced activity (22 vs 28 U/sec). In contrast, the H275Y/Q222R mutant showed a significant decrease of both affinity (40 μM) and activity (7 U/sec). The WT, H275Y, H275Y/M234V and H275Y/N344D recombinants had comparable replicative capacities contrasting with H275Y/Q222R mutant whose viral titers were significantly reduced. All studied mutations reduced the cell surface NA activity compared to WT with the maximum reduction being obtained for the H275Y/Q222R mutant. Comparable infectivity and transmissibility were seen between the WT and the H275Y mutant in ferrets whereas the H275Y/Q222R mutant was associated with significantly lower lung viral titers. In conclusion, the Q222R reversion mutation compromised Bris07-like H1N1 virus in vitro and in vivo. Thus, the R222Q NA mutation present in the WT virus may have facilitated the emergence of NAI-resistant Bris07 variants.     

Transient alteration of cellular redox buffering before irradiation triggers apoptosis in head and neck carcinoma stem and non-stem cells

Background

Head and neck squamous cell carcinoma (HNSCC) is an aggressive and recurrent malignancy owing to intrinsic radioresistance and lack of induction of apoptosis. The major focus of this work was to design a transient glutathione depleting strategy during the course of irradiation of HNSCC in order to overcome their radioresistance associated with redox adaptation.

Methodology/Principal Findings

Treatment of SQ20B cells with dimethylfumarate (DMF), a GSH-depleting agent, and L-Buthionine sulfoximine (BSO), an inhibitor of GSH biosynthesis 4 h before a 10 Gy irradiation led to the lowering of the endogenous GSH content to less than 10% of that in control cells and to the triggering of radiation-induced apoptotic cell death. The sequence of biochemical events after GSH depletion and irradiation included ASK-1 followed by JNK activation which resulted in the triggering of the intrinsic apoptotic pathway through Bax translocation to mitochondria.

Conclusions

This transient GSH depletion also triggered radiation-induced cell death in SQ20B stem cells, a key event to overcome locoregional recurrence of HNSCC. Finally, our in vivo data highlight the relevance for further clinical trials of endogenous redox modulation to enhance the cytotoxic effects of radiotherapy.     

Immunogenicity is not improved by increased antigen dose or booster dosing of seasonal influenza vaccine in a randomized trial of HIV infected adults

Introduction

The risk of poor vaccine immunogenicity and more severe influenza disease in HIV necessitate strategies to improve vaccine efficacy.

Methods

A randomized, multi-centered, controlled, vaccine trial with three parallel groups was conducted at 12 CIHR Canadian HIV Trials Network sites. Three dosing strategies were used in HIV infected adults (18 to 60 years): two standard doses over 28 days, two double doses over 28 days and a single standard dose of influenza vaccine, administered prior to the 2008 influenza season. A trivalent killed split non-adjuvanted influenza vaccine (Fluviral™) was used. Serum hemagglutinin inhibition (HAI) activity for the three influenza strains in the vaccine was measured to assess immunogenicity.

Results

297 of 298 participants received at least one injection. Baseline CD4 (median 470 cells/µL) and HIV RNA (76% of patients with viral load <50 copies/mL) were similar between groups. 89% were on HAART. The overall immunogenicity of influenza vaccine across time points and the three influenza strains assessed was poor (Range HAI ≥40 = 31–58%). Double dose plus double dose booster slightly increased the proportion achieving HAI titre doubling from baseline for A/Brisbane and B/Florida at weeks 4, 8 and 20 compared to standard vaccine dose. Increased immunogenicity with increased antigen dose and booster dosing was most apparent in participants with unsuppressed HIV RNA at baseline. None of 8 serious adverse events were thought to be immunization-related.

Conclusion

Even with increased antigen dose and booster dosing, non-adjuvanted influenza vaccine immunogenicity is poor in HIV infected individuals. Alternative influenza vaccines are required in this hyporesponsive population.

Trial Registration

ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT00764998","term_id":"NCT00764998"}}NCT00764998     

Target for improvement: a cluster randomised trial of public involvement in quality-indicator prioritisation (intervention development and study protocol)

Background

Violence against women (VAW) is a major public health problem. Translation of VAW research to policy and practice is an area that remains understudied, but provides the opportunity to examine knowledge translation and exchange (KTE) processes in a complex, multi-stakeholder context. In a series of studies including two randomized trials, the McMaster University VAW Research Program studied one key research gap: evidence about the effectiveness of screening women for exposure to intimate partner violence. This project developed and evaluated KTE strategies to share research findings with policymakers, health and community service providers, and women's advocates.

Methods

A longitudinal cross-sectional design, applying concurrent mixed data collection methods (surveys, interviews, and focus groups), was used to evaluate the utility of specific KTE strategies, including a series of workshops and a day-long Family Violence Knowledge Exchange Forum, on research sharing, uptake, and use.

Results

Participants valued the opportunity to meet with researchers, provide feedback on key messages, and make personal connections with other stakeholders. A number of factors specific to the knowledge itself, stakeholders' contexts, and the nature of the knowledge gap being addressed influenced the uptake, sharing, and use of the research. The types of knowledge use changed across time, and were specifically related to both the types of decisions being made, and to stage of decision making; most reported use was conceptual or symbolic, with few examples of instrumental use. Participants did report actively sharing the research findings with their own networks. Further examination of these second-order knowledge-sharing processes is required, including development of appropriate methods and measures for its assessment. Some participants reported that they would not use the research evidence in their decision making when it contradicted professional experiences, while others used it to support apparently contradictory positions. The online wiki-based 'community of interest' requested by participants was not used.

Conclusions

Mobilizing knowledge in the area of VAW practice and policy is complex and resource-intensive, and must acknowledge and respect the values of identified knowledge users, while balancing the objectivity of the research and researchers. This paper provides important lessons learned about these processes, including attending to the potential unintended consequences of knowledge sharing.     

Cardiac-specific blockade of NF-kappaB in cardiac pathophysiology: differences between acute and chronic stimuli in vivo

The role of NF-kappaB in cardiac physiology and pathophysiology has been difficult to delineate due to the inability to specifically block NF-kappaB signaling in the heart. Cardiac-specific transgenic models have recently been developed that repress NF-kappaB activation by preventing phosphorylation at specific serine residues of the inhibitory kappaB (IkappaB) protein isoform IkappaBalpha. However, these models are unable to completely block NF-kappaB because of a second signaling pathway that regulates NF-kappaB function via Tyr42 phosphorylation of IkappaBalpha. We report the development of transgenic (3M) mouse lines that express the mutant IkappaBalpha(S32A,S36A,Y42F) in a cardiac-specific manner. NF-kappaB activation in cardiomyopathic TNF-1.6 mice is completely blocked by the 3M transgene but only partially blocked (70-80%) by the previously described double-mutant 2M [IkappaBalpha(S32A,S36A)] transgene, which demonstrates the action of two proximal pathways for NF-kappaB activation in TNF-alpha-induced cardiomyopathy. In contrast, after acute stimuli including administration of TNF-alpha and ischemia-reperfusion (I/R), NF-kappaB activation is blocked in both 2M and 3M transgenic mice. This result suggests that phosphorylation of the regulatory Ser32 and Ser36 predominantly mediates NF-kappaB activation in these situations. We show that infarct size after I/R is reduced by 70% in 3M transgenic mice, which conclusively demonstrates that NF-kappaB is involved in I/R injury. In summary, we have engineered novel transgenic mice that allow us to distinguish two major proximal pathways for NF-kappaB activation. Our results demonstrate that the serine and tyrosine phosphorylation pathways are differentially activated during different pathophysiological processes (cardiomyopathy and I/R injury) and that NF-kappaB contributes to infarct development after I/R.     

Pathogenesis of human metapneumovirus lung infection in BALB/c mice and cotton rats

Human metapneumovirus (hMPV) is a newly described member of the Paramyxoviridae family causing acute respiratory tract infections, especially in young children. We studied the pathogenesis of this viral infection in two experimental small animal models (BALB/c mice and cotton rats). Significant viral replication in the lungs of both animals was found following an intranasal challenge of 10(8) 50% tissue culture infectious doses (TCID50) and persisted for <2 and <3 weeks in the case of cotton rats and mice, respectively. Peak viral loads were found on day 5 postinfection in both mice (mean of 1.92 x 10(7) TCID50/g lung) and cotton rats (mean of 1.03 x 10(5) TCID50/g). Clinical symptoms consisting of breathing difficulties, ruffled fur, and weight loss were noted in mice only around the time of peak viral replication. Most significant pulmonary inflammatory changes and peak expression of macrophage inflammatory protein 1alpha, gamma interferon, and RANTES occurred at the time of maximal viral replication (day 5) in both models. Cellular infiltration occurred predominantly around and within alveoli and persisted for at least 21 days in mice, whereas it was more limited in time with more peribronchiolitis in cotton rats. Both animal models would be of great value in evaluating different therapeutic agents, as well as vaccine candidates against hMPV.     

Identification of a binding domain of the endothelin-B receptor using a selective IRL-1620-derived photoprobe

On the basis of the structure of IRL-1620, a specific agonist of the endothelin-B receptor subtype (ET(B)), a few photosensitive analogues were developed to investigate the binding domain of the receptor. Among those, a derivative containing the photoreactive amino acid, p-benzoyl-l-phenylalanine in position 5 showed, as assessed with endothelin-A (ET(A)) and ET(B) receptor paradigms, pharmacological properties very similar to those of IRL-1620. The binding capacity of the probe was also evaluated on transfected Chinese hamster ovary (CHO) cells overexpressing the human ET(B) receptor. Data showed that binding of the radiolabeled peptide was inhibited by ET-1 and IRL-1620. Therefore, this photolabile probe was used to label the ET(B) receptor found in CHO cells. Photolabeling produced a ligand-protein complex appearing on SDS-PAGE at around 49 kDa. An excess of ET-1 or IRL-1620 completely abolished the formation of the complex, showing the selectivity of the photoprobe. Digestions of the [Bpa(5),Tyr((125)I)(6)]IRL-1620-ET(B) complex were carried out, and receptor fragments were analyzed to define the region of the receptor where the ligand interacts. Results showed that Endo Lys-C digestion gave a 3.8-kDa fragment corresponding to the Asp(274)-Lys(303) segment, whereas migration after V8 digestion revealed a fragment of 4.6 kDa. Because the fragments of these two digestions must overlap, the latter would be the Trp(275)-Asp(313) stretch. A cleavage with CNBr confirmed the identity of the binding domain by giving a fragment of 3.6 kDa, corresponding to Gln(267)-Met(296). Thus, the combined cleavage data strongly suggested that the agonist binding domain of ET(B) includes a portion of the fifth transmembrane domain, between residues Trp(275) and Met(296).