Early versus delayed decompression for traumatic cervical spinal cord injury: results of the Surgical Timing in Acute Spinal Cord Injury Study (STASCIS)

Background

There is convincing preclinical evidence that early decompression in the setting of spinal cord injury (SCI) improves neurologic outcomes. However, the effect of early surgical decompression in patients with acute SCI remains uncertain. Our objective was to evaluate the relative effectiveness of early (<24 hours after injury) versus late (≥24 hours after injury) decompressive surgery after traumatic cervical SCI.

Methods

We performed a multicenter, international, prospective cohort study (Surgical Timing in Acute Spinal Cord Injury Study: STASCIS) in adults aged 16–80 with cervical SCI. Enrolment occurred between 2002 and 2009 at 6 North American centers. The primary outcome was ordinal change in ASIA Impairment Scale (AIS) grade at 6 months follow-up. Secondary outcomes included assessments of complications rates and mortality.

Findings

A total of 313 patients with acute cervical SCI were enrolled. Of these, 182 underwent early surgery, at a mean of 14.2(±5.4) hours, with the remaining 131 having late surgery, at a mean of 48.3(±29.3) hours. Of the 222 patients with follow-up available at 6 months post injury, 19.8% of patients undergoing early surgery showed a ≥2 grade improvement in AIS compared to 8.8% in the late decompression group (OR = 2.57, 95% CI:1.11,5.97). In the multivariate analysis, adjusted for preoperative neurological status and steroid administration, the odds of at least a 2 grade AIS improvement were 2.8 times higher amongst those who underwent early surgery as compared to those who underwent late surgery (OR = 2.83, 95% CI:1.10,7.28). During the 30 day post injury period, there was 1 mortality in both of the surgical groups. Complications occurred in 24.2% of early surgery patients and 30.5% of late surgery patients (p = 0.21).

Conclusion

Decompression prior to 24 hours after SCI can be performed safely and is associated with improved neurologic outcome, defined as at least a 2 grade AIS improvement at 6 months follow-up.     

Electric Field and Mobility Dependent First‐Order Recombination Losses in Organic Solar Cells

The origin of photocurrent losses in the power‐generating regime of organic solar cells (OSCs) remains a controversial topic, although recent literature suggests that the competition between bimolecular recombination and charge extraction determines the bias dependence of the photocurrent. Here the steady‐state recombination dynamics is studied in bulk‐heterojunction OSCs with different hole mobilities from short‐circuit to maximum power point. It is shown that in this regime, in contrast to previous transient extracted charge and absorption spectroscopy studies, first‐order recombination outweighs bimolecular recombination of photogenerated charge carriers. This study demonstrates that the first‐order losses increase with decreasing slower carrier mobility, and attributes them to either mobilization of charges trapped at the donor:acceptor interface through the Poole–Frenkel effect, and/or recombination of photogenerated and injected charges. The dependence of both first‐order and higher‐order losses on the slower carrier mobility explains why the field dependence of OSC efficiencies has historically been attributed to charge‐extraction losses.     

The influence of arsenic chemical form and concentration on Spartina patens and Spartina alterniflora growth and tissue arsenic concentration

Arsenic (As) uptake by two perennial coastal marsh grasses growing in hydroponic conditions was studied in relation to the chemical form and concentration of As added to nutrient solution. A 4×3×2 factorial experiment was conducted with treatments consisting of four As chemical forms [arsenite, As(III); arsenate, As(V); monomethyl arsonic acid, MMAA; and dimethyl arsinic acid, DMAA], three As concentrations (0.2, 0.8, and 2.0 mg As L^-1) and two plant species (Spartina patens and Spartina alterniflora). Arsenic phytoavailability and phytotoxicity were primarily determined by the As chemical form present in the nutrient solution, though As concentration also influenced both As availability and toxicity. Application of As(V) increased root, shoot and total dry matter production; this positive plant growth response may be linked with P nutrition. Organic arsenicals and As(III) were the most phytotoxic species to both marsh grasses when plant growth was considered. Arsenic uptake and transport in plant were species-specific. Phytoavailability of As followed the trend DMAA MMAA As(V) < As(III). Root and shoot As concentrations significantly increased with increasing As application rates to the rooting medium, regardless of the As chemical form. Upon absorption, inorganic arsenicals and MMAA were mainly accumulated in the root system, while DMAA was readily translocated to the shoot.     

Nonfullerene Acceptors: A Renaissance in Organic Photovoltaics?

Efficient, low‐cost, and low‐embodied energy photovoltaics are key enablers of the global decarbonization agenda. In addition to the market‐leading crystalline silicon technology, several other promising candidates are under active investigation with the perovskites leading the way with single‐junction efficiencies exceeding 25% at the lab‐scale. So‐called organic photovoltaics (solar cells based upon organic semiconductors), particularly those that can be solution processed, have long promised the Nirvana of ultralow cost and very short energy payback times. However, relatively low efficiencies, poor long‐term stability, and issues with manufacturing at scale have so far prevented truly meaningful commercialization of the technology. The recent emergence of the so‐called nonfullerene electron acceptors is potentially about to shift this dynamic—they have delivered a step change in performance in a relatively short period of time. In this Essay, the basic properties of these new materials, their pros and cons, what we know and what we do not know are explored.     

Ischemic insult to cerebellar Purkinje cells causes diminished GABAA receptor function and allopregnanolone neuroprotection is associated with GABAA receptor stabilization

Cerebellar Purkinje cells (PC) are particularly vulnerable to ischemic injury and excitotoxicity, although the molecular basis of this sensitivity remains unclear. We tested the hypothesis that ischemia causes rapid down-regulation of GABA(A) receptors in cerebellar PC, thereby increasing susceptibility to excitotoxicity. Oxygen-glucose deprivation (OGD) caused a decline in functional GABA(A) receptors, within the first hour of re-oxygenation. Decreased amplitude of miniature inhibitory post-synaptic potentials confirmed that OGD caused a significant decrease in functional synaptic GABA(A) receptors and quantitative Western blot analysis demonstrated the loss of GABA(A) receptor current was associated with a decline in total receptor protein. Interestingly, the potent neuroprotectant allopregnanolone (ALLO) prevented the decline in GABA(A) receptor current and protein. Consistent with our in vitro data, global ischemia in mice caused a significant decline in total cerebellar GABA(A) receptor protein and PC specific immunoreactivity. Moreover, ALLO provided strong protection of PC and prevented ischemia-induced decline in GABA(A) receptor protein. Our findings indicate that ischemia causes a rapid and sustained loss of GABA(A) receptors in PC, whereas ALLO prevents the decline in GABA(A) receptors and protects against ischemia-induced damage. Thus, interventions which prevent ischemia-induced decline in GABA(A) receptors may represent a novel neuroprotective strategy.     

Association of physical activity and the metabolic syndrome in children and adolescents: CASPIAN Study

BACKGROUND/AIM: To determine the association of physical activity and the metabolic syndrome in a large national-representative sample of children. METHODS: This study was performed in 2003-2004 on 4,811 school students aged 6-18 years, selected by multi-stage random cluster sampling from six provinces in Iran. We assessed the level of physical activity using a standardized questionnaire, and categorized it to the tertiles. The metabolic syndrome was defined based on criteria analogous to those of the Adult Treatment Panel III. RESULTS: The participants comprised 2,248 boys and 2,563 girls with a mean age of 12.07 +/- 3.2 years. In all age groups, boys were more physically active than girls. The metabolic syndrome was detected in 14.1% of participants, and its prevalence was higher in those subjects in the 1st, 2nd and 3rd tertiles of physical activity, respectively (15.1 vs.14.2 and 13.1%, respectively, p <0.05). This difference was seen in boys, while no difference was found between girls in the 2nd and 3rd tertiles of physical activity. Physical activity was linked to a cluster of factors consisting of high-density lipoprotein-cholesterol and waist circumference, followed by triglycerides in boys, and of triglycerides, waist circumference and blood pressure in girls. In both genders, before and after adjustment for age and body mass index, low levels of physical activity significantly increased the risk of having the metabolic syndrome [in boys: OR: 1.8, 95% CI: 1.1, 2.1; and in girls, OR: 1.6 (1.1, 1.9)]. CONCLUSION: We found an association between physical activity and the metabolic syndrome, which was independent of body mass index and age. Children should be encouraged to have greater physical activity.