Dental pathologies in ten free-ranging chimpanzees from Gombe National Park, Tanzania

The dental remains of ten adult chimpanzees from Gombe National Park, Tanzania, were examined for enamel attrition, caries, abscesses, periodontal disease, and tooth loss. Age was the underlying factor in the development of dental pathology, in that enamel wear was present to some extent in all ten but was uniformly severe only in the three for whom estimated age at death was 39-43 years. In turn, enamel wear appears to have been the direct cause of abscess development, periodontal disease, and tooth loss. Periodontal disease was commonly expressed as alveolar resorption, particularly around the premolars and molars. This involvement was variable in all except the two youngest. Some interesting wear patterns were evident in the form of deep grooves in the upper incisors and dramatic notching of the lower canines. These patterns, and enamel attrition in general, were attributed to normal mastication and to various stripping activities. Only one carious lesion was observed, in a male with an estimated age of 26 years. An accurate assessment of the actual prevalence of caries was obscured by enamel wear and tooth loss in the older individuals.     

CCN2 promotes keratinocyte adhesion and migration via integrin α5β1

Background

CCN2, (a.k.a. connective tissue growth factor and CTGF) has emerged as a regulator of cell migration. While the importance of CCN2 for the fibrotic process in wound healing has been well studied, the effect of CCN2 on keratinocyte function is not well understood. In this study, we investigated the mechanism behind CCN2-driven keratinocyte adhesion and migration.Materials and methods: Adhesion assays were performed by coating wells with 10 μg/ml fibronectin (FN) or phosphate-buffered saline (PBS). Keratinocytes were seeded in the presence or absence of 200 ng/ml CCN2, 5 mmol/l ethylenediaminetetraacetic acid, 10 mmol/l cations, 500 μl arginine–glycine–aspartic acid (RGD), 500 μM arginine–glycine–glutamate–serine (RGES), and 10 μg/ml anti-integrin blocking antibodies. Migration studies were performed using a modified Boyden chamber assay. Quantitative PCR was used to study the effect of CCN2 on integrin subunit mRNA expression. To block intracellular pathways, keratinocytes were pretreated with 20 μM PD98059 (MEK-1 inhibitor) or 20 μM PF573228 (FAK inhibitor) for 60 min prior the addition of CCN2. Western blot was used to measure CCN2, p-ERK1/2, and ERK1/2.Results: CCN2 enhanced keratinocyte adhesion to fibronectin via integrin α5β1. The addition of anti-integrin α5β1 antibodies reduced CCN2-mediated keratinocyte migration. In addition, CCN2 regulated mRNA and protein expression of integrin subunits α5 and β1. CCN2 activated the FAK-MAPK signaling pathway, and pretreatment with MEK1-specific inhibitor PD98059 markedly reduced CCN2-induced keratinocyte migration.Conclusions: Our results demonstrate that CCN2 enhances keratinocyte adhesion and migration through integrin α5β1 and activation of the FAK-MAPK signaling cascade.     

Diversity of Rotavirus Strains Causing Diarrhea in <5 Years Old Chinese Children: A Systematic Review

Background

We conducted a systematic review of the diversity and fluctuation of group A rotavirus strains circulating in China.

Methods and Findings

Studies of rotavirus-based diarrhea among children less than 5 years, published in English or Chinese between 1994 and 2012, were searched in PubMed, SinoMed, and CNKI and reviewed by applying standardized algorithms. The temporal and spatial trends of genotyping and serotyping were analyzed using a random-effects model. Ninety-three studies met the inclusion/exclusion criteria and were included in the meta-analysis. Overall, 22,112 and 10,660 rotavirus samples had been examined for G and P types, respectively. The most common G types were G1 (39·5%), G3 (35·6%), G2 (1·3%), and G9 (0·1%). Among P types, P[8] (54·6%) was the predominant type, followed by P[4] (11·1%) and P6 (0·1%). The most common G-P combinations were G3P[8] (32·1%) and G1P[8] (24·5%), followed by G2P[6] (13·2%) and G2P[4] (10·1%). Before 2000, serotype G1 was the predominant strain and accounted for 74·3% of all rotavirus infections; however, since 2000, G3 (45·2%) has been the predominant strain. Rotavirus P types showed little variation over the study period.

Conclusion

Despite the variation of serotypes observed in China, the G1, G2, G3, and G4 serotypes accounted for most rotavirus strains in recent decades. These results suggest that Chinese children will be adequately protected with currently available or forthcoming rotavirus vaccines.     

Deconstructing Ixodes ricinus: a partial matrix model allowing mapping of tick development,mortality and activity rates

A stage‐structured Leslie matrix model of a partial, discrete population of Ixodes ricinus (Linnaeus) (Ixodida: Ixodidae) ticks was developed to elucidate the impact of climate trends on the distribution and phenology of this species in the western Palaearctic. The model calculates development and mortality rates for each instar and evaluates recruitment rates based on the development of the tick population. The model captures the changes in development and mortality rates, providing a coherent index of performance correlated with the tick's geographic range. Maximum development rates are recorded for latitudes south of 36 °N and are spatially correlated with sites of maximum temperature, highest saturation deficit and highest mortality. The maximum available developmental time (the total annual time during which temperature allows development) for I. ricinus in the western Palaearctic is < 45% of the total year. North of 60 °N, available developmental time decreases sharply to only 15% of the year. The latitudinal boundary at which survival rates sharply drop is 43–46 °N, clearly delimiting the classically recognized extent of the main tick populations. The pattern of activity for larval–nymphal synchrony shows a clear west–east pattern. The model demonstrates the impact of climate according to tick stage and geographic location, and provides a practical framework for testing how the tick's lifecycle is affected by climate change.     

Energy Efficient Neural Stimulation: Coupling Circuit Design and Membrane Biophysics

The delivery of therapeutic levels of electrical current to neural tissue is a well-established treatment for numerous indications such as Parkinson’s disease and chronic pain. While the neuromodulation medical device industry has experienced steady clinical growth over the last two decades, much of the core technology underlying implanted pulse generators remain unchanged. In this study we propose some new methods for achieving increased energy-efficiency during neural stimulation. The first method exploits the biophysical features of excitable tissue through the use of a centered-triangular stimulation waveform. Neural activation with this waveform is achieved with a statistically significant reduction in energy compared to traditional rectangular waveforms. The second method demonstrates energy savings that could be achieved by advanced circuitry design. We show that the traditional practice of using a fixed compliance voltage for constant-current stimulation results in substantial energy loss. A portion of this energy can be recuperated by adjusting the compliance voltage to real-time requirements. Lastly, we demonstrate the potential impact of axon fiber diameter on defining the energy-optimal pulse-width for stimulation. When designing implantable pulse generators for energy efficiency, we propose that the future combination of a variable compliance system, a centered-triangular stimulus waveform, and an axon diameter specific stimulation pulse-width has great potential to reduce energy consumption and prolong battery life in neuromodulation devices.