13C NMR relaxation studies of poly(vinyl alcohol) and its derivatives

Spin-lattice relaxation times (T₁) have been measured by ¹³C NMR for poly(vinyl alcohol), poly(vinyl benzoate), poly(vinyl cinnamate) and poly(vinyl acetate) in dimethyl sulfoxide as a function of temperature and concentration. As expected, T₁ increases with increasing temperature and decreases with increasing polymer concentration. The influence of the microstructure (tacticity) of the polymers on the relaxation times is negligible. T₁ for the methine carbon of the polymer main chain is observed to serve as a measure of the rigidity and/or mobility of the chain. Assuming isotropic motion of the polymer chains, the activation energies for the protonated carbons were determined using the calculated correlation times.     

Low cardiac output complicating pericardiectomy for pericardial tamponade

Neoplastic involvement of the pericardium resulting in an effusion and subsequent tamponade is an emergency requiring prompt decompression, generally safely accomplished by subxiphoid pericardiectomy. However, the current case report describes a patient with florid pericardial tamponade who underwent surgical decompression with transient hemodynamic improvement, who then rapidly developed progressive, heart failure and death. This paradoxical response to pericardial decompression, similar to that seen occasionally with pericardiectomy in constrictive pericarditis, may be more frequent than currently appreciated. Its cause may relate to the sudden removal of the chronic external ventricular support from the effusion resulting in ventricular dilatation and failure.     

Expression of Hedgehog ligand and signal transduction components in mutually distinct isocitrate dehydrogenase mutant glioma cells supports a role for paracrine signaling

DNA methylation plays an important role in cancer biology and methylation events are important prognostic and predictive markers in many tumor types. We have used methylation-specific multiplex ligation-dependent probe amplification to survey the methylation status of MGMT and 25 tumor suppressor genes in 73 glioblastoma cases. The data obtained was correlated with overall survival and response to treatment. The study revealed that methylation of promoter regions in TP73 (seven patients), THBS1 (eight patients) and PYCARD (nine patients) was associated with improved outcome, whereas GATA5 (21 patients) and WT1 (24 patients) promoter methylation were associated with poor outcome. In patients treated with temozolomide and radiation MGMT and PYCARD promoter methylation events remained associated with improved survival whereas GATA5 was associated with a poor outcome. The identification of GATA5 promoter methylation in glioblastoma has not previously been reported. Furthermore, a cumulative methylation score separated patients into survival groups better than any single methylation event. In conclusion, we have identified specific methylation events associated with patient outcome and treatment response in glioblastoma, and these may be of functional and predictive/prognostic significance. This study therefore provides novel candidates and approaches for future prospective validation.     

In vitro anti-hyperglycemia properties of the aqueous stem bark extract from Strychnos henningsii (Gilg)

Strychnos henningsii (SH) is a plant commonly used in southern African traditional medicine for the management of diabetes mellitus. Previous in vivo studies showed that a stem bark extract improves glycemic control in a diabetic animal model. Meanwhile, the mechanism of action has not been elucidated. The present study therefore investigated various in vitro models known to target glucose homeostasis and its direct complications. The plant extract was found to stimulate both basal and insulin stimulated glucose uptake in differentiated 3T3-L1 cells but not in Chang liver cells. The effect on 3T3-L1 cells appears independent of PPARγ as the extract did not stimulate adipogenesis. Although, SH extract was inhibitory toward intestinal alpha glucosidase, the physiological relevance is doubtful based on the recommended dosages. The extract strongly inhibited protein glycation which, at least in part, may be explained by the antioxidant and phenolic content of this plant. Cytotoxicity in Chang liver cells yielded an IC₅₀ value of 130.0 μg/mL raising concern that continual exposure to this herbal remedy may initiate hepatotoxicity. The finding from this study suggests that SH extract may attenuate hyperglycemia through enhanced peripheral tissue glucose utilization.     

Mitochondrial calcium uniporter regulator 1 (MCUR1) regulates the calcium threshold for the mitochondrial permeability transition

During the mitochondrial permeability transition, a large channel in the inner mitochondrial membrane opens, leading to the loss of multiple mitochondrial solutes and cell death. Key triggers include excessive reactive oxygen species and mitochondrial calcium overload, factors implicated in neuronal and cardiac pathophysiology. Examining the differential behavior of mitochondrial Ca²⁺ overload in Drosophila versus human cells allowed us to identify a gene, MCUR1, which, when expressed in Drosophila cells, conferred permeability transition sensitive to electrophoretic Ca²⁺ uptake. Conversely, inhibiting MCUR1 in mammalian cells increased the Ca²⁺ threshold for inducing permeability transition. The effect was specific to the permeability transition induced by Ca²⁺, and such resistance to overload translated into improved cell survival. Thus, MCUR1 expression regulates the Ca²⁺ threshold required for permeability transition.The mitochondrial permeability transition (MPT) pore is large, and its opening collapses the mitochondrial membrane potential (ΔΨ), depleting the matrix of solutes <1.5 kDa. The osmotic imbalance swells and disrupts mitochondria, leading to cell death. The molecular structure of the MPT pore is unknown, although cyclophilin D [peptidyl-prolyl isomerase F (PPIF)], the ADP/ATP translocase, the F1-FO-ATP synthase, and spastic paraplegia 7 are key for its function (1–5).Key triggers for the MPT include oxidative damage and Ca²⁺ overload. Reactive oxygen species attack a cysteine residue in mammalian PPIF (6, 7), but how Ca²⁺ overload activates the pore is unknown. Elimination of the known regulators typically inhibits the sensitivity of the MPT globally, not favoring any particular trigger (8–10). Because Ca²⁺ overload promotes cell death in excitable cells, targeting this pathway selectively may prove beneficial.To discover novel regulators specific to mitochondrial Ca²⁺ overload, we studied MPT in Drosophila S2R+ cells, a system where screens have identified molecules involved in Ca²⁺ transport (11–13). We found that mitochondria within these cells were resistant to Ca²⁺ overload (14) but did possess an MPT. Moreover, we identified a mammalian gene, mitochondrial calcium uniporter regulator 1 (MCUR1), with no known Drosophila homolog, which is able to alter the MPT Ca²⁺ threshold. Inhibiting this gene confers resistance from cell death mediated by mitochondrial Ca²⁺ overload.     

Efficacy of the FIFA 11+ Warm-Up Programme in Male Youth Football: A Cluster Randomised Controlled Trial

The FIFA 11+ is a structured warm-up programme specially designed to prevent injuries among football players from age 14 years and above. However, studies to prove its efficacy are generally few and it is yet to be tested in male youth footballers and among African players. The purpose of the study was to examine the efficacy of the FIFA 11+ programme in reducing the risk of injuries among male youth football players of the Lagos Junior League. A cluster randomised controlled trial was conducted. All the 20 teams (414 players aged 14 -19 years) in the Premier League division were block-randomised into either an intervention (INT) or a control (CON) group. The INT group performed the FIFA 11+ exercises as warm-up during training sessions and the CON group performed usual warm-up. Participating teams were prospectively followed through an entire league season of 6 months in which they were visited every week to assess injured players for time-loss injuries in both groups. The primary outcomes were any injury to the players, injuries by type of exposure and injuries specific to the lower extremities. The secondary outcomes were injuries reported by body location, aetiology, mechanism and severity. In total, 130 injuries were recorded affecting 104 (25%) of the 416 players. Team and player compliance with the INT was 60% and 74% respectively. Based on the primary outcome measures of the study, the FIFA 11+ programme significantly reduced the overall rate of injury in the INT group by 41% [RR = 0.59 (95% CI: 0.40 – 0.86; p = 0.006)] and all lower extremity injuries by 48% [RR = 0.52 (95% CI: 0.34 – 0.82; p = 0.004)]. However, the rate of injury reduction based on secondary outcomes mostly did not reach the level of statistical significance. The FIFA 11+ programme is effective in reducing the rates of injuries in male youth football players.

Key points

• The FIFA 11+ has only been tested in randomised controlled trials conducted on female youth football players; this study reports its efficacy in male youth football for the first time
• The FIFA 11+ programme significantly reduced the overall rate of injuries and lower extremity injuries in male youth football players
• Youth football administrators in Africa and other parts of the world should pursue the implementation of the FIFA 11+ in order to minimize the incidence of injuries among players

Key words: Injury prevention, neuromuscular training, FIFA, sports     

Does it Really Matter Where Women Live? A Multilevel Analysis of the Determinants of Postnatal Care in Nigeria

Although postnatal care is one of the major interventions recommended for the reduction of maternal and newborn deaths worldwide, almost two-third (56 %) of women in Nigeria do not receive postnatal care. Attempts to explain this situation have focused on individual and household level factors, but the role of community characteristics has received less attention.This study examines community factors associated with the receipt of postnatal care in Nigeria and the moderating effects of community factors on the association between individual factors and postnatal care. Data was drawn from the 2008 Nigeria Demographic and Health Survey, and a sample of 17,846 women aged 15–49 years was selected. We employed a multilevel logistic regression analysis to identify community factors associated with postnatal care. Our findings showed that significant variations in receiving postnatal care exist across communities. Specifically, Nigerian women’s likelihood of receiving postnatal care is a function of where they reside. Living in communities with a high proportion of educated women (OR = 2.04; 95 % CI = 1.32–3.16; p < 0.001) and a high proportion of those who have had a health facility delivery (OR = 17.86; 95 % CI = 8.34–38.24; p < 0.001) was significantly associated with an increased likelihood of receiving postnatal care. Community women’s education moderated the association between ethnic origin and postnatal care. Community variance in postnatal care was significant (τ = 10.352, p = 0.001). Community interventions aimed at improving postnatal care should take into account the community context in which women live. To close the gap in community variations in postnatal care, secondary and higher education for women, and health facility delivery should be increased in disadvantaged communities.