Benthic Carbon Mineralization and Nutrient Turnover in a Scottish Sea Loch: An Integrative In Situ Study.

Based on in situ microprofiles, chamber incubations and eddy covariance measurements, we investigated the benthic carbon mineralization and nutrient regeneration in a ~65-m-deep sedimentation basin of Loch Etive, UK. The sediment hosted a considerable amount of infauna that was dominated by the brittle star A. filiformis. The numerous burrows were intensively irrigated enhancing the benthic in situ O2 uptake by ~50 %, and inducing highly variable redox conditions and O2 distribution in the surface sediment as also documented by complementary laboratory-based planar optode measurements. The average benthic O2 exchange as derived by chamber incubations and the eddy covariance approach were similar (14.9 ± 2.5 and 13.1 ± 9.0 mmol m-2 day-1) providing confidence in the two measuring approaches. Moreover, the non-invasive eddy approach revealed a flow-dependent benthic O2 flux that was partly ascribed to enhanced ventilation of infauna burrows during periods of elevated flow rates. The ratio in exchange rates of ΣCO2 and O2 was close to unity, confirming that the O2 uptake was a good proxy for the benthic carbon mineralization in this setting. The infauna activity resulted in highly dynamic redox conditions that presumably facilitated an efficient degradation of both terrestrial and marine-derived organic material. The complex O2 dynamics of the burrow environment also concurrently stimulated nitrification and coupled denitrification rates making the sediment an efficient sink for bioavailable nitrogen. Furthermore, bioturbation mediated a high efflux of dissolved phosphorus and silicate. The study documents a high spatial and temporal variation in benthic solute exchange with important implications for benthic turnover of organic carbon and nutrients. However, more long-term in situ investigations with like approaches are required to fully understand how environmental events and spatio-temporal variations interrelate to the overall biogeochemical functioning of coastal sediments.

A novel approach to induction and rehabilitation of deficits in forelimb function in a rat model of ischemic stroke.

AIM: Constraint-induced movement therapy (CIMT), which forces use of the impaired arm following unilateral stroke, promotes functional recovery in the clinic but animal models of CIMT have yielded mixed results. The aim of this study is to develop a refined endothelin-1 (ET-1) model of focal ischemic injury in rats that resulted in reproducible, well-defined lesions and reliable upper extremity impairments, and to determine if an appetitively motivated form of rehabilitation (voluntary forced use movement therapy; FUMT) would accelerate post-ischemic motor recovery. METHODS: Male Sprague Dawley rats (3 months old) were given multiple intracerebral microinjections of ET-1 into the sensorimotor cortex and dorsolateral striatum. Sham-operated rats received the same surgical procedure up to but not including the drill holes on the skull. Functional deficits were assessed using two tests of forelimb placing, a forelimb postural reflex test, a forelimb asymmetry test, and a horizontal ladder test. In a separate experiment ET-1 stroke rats were subjected to daily rehabilitation with FUMT or with a control therapy beginning on post-surgery d 5. Performance and post-mortem analysis of lesion volume and regional BDNF expression were measured. RESULTS: Following microinjections of ET-1 animals exhibited significant deficits in contralateral forelimb function on a variety of tests compared with the sham group. These deficits persisted for up to 20 d with no mortality and were associated with consistent lesion volumes. FUMT therapy resulted in a modest but significantly accelerated recovery in the forelimb function as compared with the control therapy, but did not affect lesion size or BDNF expression in the ipsilesional hemisphere. CONCLUSION: We conclude that refined ET-1 microinjection protocols and forcing use of the impaired forelimb in an appetitively motivated paradigm may prove useful in developing strategies to study post-ischemic rehabilitation and neuroplasticity.

The convergent procedure: a multidisciplinary atrial fibrillation treatment.

BACKGROUND: Persistent atrial fibrillation (AF) and long-standing persistent AF (LSPAF) are difficult to treat. Epicardial surgical and percutaneous catheter ablations have lower success rates in these patients. The convergent procedure, an endoscopic transdiaphragmatic ablation procedure with conventional percutaneous endocardial ablation, is examined. METHODS: Twenty-eight patients with persistent AF or LSPAF underwent the convergent procedure. All underwent combined surgical epicardial radiofrequency ablation and electrophysiological transseptal endocardial ablation to electrically isolate the 4 pulmonary veins, to exclude the posterior left atrium, to ablate the coronary sinus, and to confirm block at the cavotricuspid isthmus. Follow-up was with 24-hour Holter monitoring at 3 months, and 24-hour or 7-day monitoring at 6 and 12 months. RESULTS: The mean duration of the procedure was 187 minutes (102 surgical ablation minutes; 85 endocardial ablation minutes). The mean total fluoroscopy time was 35.1 minutes. Two patients developed symptomatic pericardial effusions requiring percutaneous drainage, and 1 patient has demonstrated phrenic nerve paresis. There were no deaths. At 3 months, 87% were in sinus rhythm, and 43% were free of AF and antiarrhythmic medications (AADs). At 6 months, 76% were free from AF and AADs. CONCLUSION: The convergent procedure effectively combines surgical and electrophysiological AF expertise to provide a viable treatment option to patients with persistent AF or LSPAF. Long-term follow-up is under way.

Endothelin-1-Induced Ischemic Damage and Functional Impairment Is Mediated Primarily by NR2B-Containing NMDA Receptors.

Ischemic stroke accounts for 70-80% of stroke cases worldwide and survivors are frequently left with compromising sensorimotor deficits localized to one or more body regions. Most animal models of stroke involve transient or permanent occlusion of one or more major vessels such as the middle cerebral artery and are characterized by widespread damage to cortical and subcortical structures that result in deficits that can confound studies of neuroprotection and neurorehabilitation. Localized microinjections of the vasoconstricting peptide endothelin-1 (ET-1) into specific brain regions are becoming increasingly popular for such studies, but the pharmacology of endothelin-induced ischemic damage is poorly understood. To test the hypothesis that NMDA receptors, and particularly those containing the NR2B subunit, are involved in ET-1-mediated excitotoxicity and functional impairment, male CD1 rats (N = 32) were pre-treated with either the non-competitive NMDA antagonist MK-801 or the NR2B-selective antagonist Ro25-6981 (or vehicle) prior to unilateral microinjections of endothelin-1 into the somatosensory cortex and striatum. Rats were then tested using 4 established tests of sensory and/or motor function over 14 days. Lesion volumes were quantified post-mortem using standard histology and image analysis. Results confirmed reproducible lesions and significant deficits in all tests in vehicle-treated rats that were significantly reduced in both drug groups but were not different between drugs, providing evidence that endothelin-induced ischemic damage is mediated almost exclusively by NR2B-containing NMDA receptors.

Remote school gardens: exploring a cost-effective and novel way to engage Australian Indigenous students in nutrition and health.

OBJECTIVE: This pilot study aimed to determine the feasibility of a novel, low-cost program to get remote schools started in gardening and nutrition activities, for a lower cost than existing models, and without on-the-ground horticultural support. METHODS: A multi-site, mixed methods case study was undertaken, in which four remote schools were shipped gardening materials and a nutrition and cooking resource, and provided with horticultural support by phone and email. A support register and teacher surveys were used for four months of evaluation. RESULTS: The study demonstrated that the program is feasible, and may be associated with an increase from baseline in student's time spent cooking, gardening and on related classroom activities. CONCLUSIONS: The program was delivered economically without the need for on-the-ground staff, in a manner that was acceptable to teachers. IMPLICATIONS: This model may have application in remote schools throughout Australia, where there is a need to alter health impacting behaviours in high-risk populations. Lengthier program evaluation times and further resource development may be worth investigating in the future.

"We need our own food, to grow our own veggies " Remote Aboriginal food gardens in the Top End of Australia's Northern Territory.

OBJECTIVE: Remote Aboriginal community gardens (gardens) frequently operate below their full potential. A set of gardening sustainability principles may improve their planning, operation and long-term sustainability. This paper aims to document the principles of sustainability of non-profit remote Aboriginal community gardens in the Top End of the Northern Territory. METHODS: Throughout 2011, gardens in the Top End of the Northern Territory were visited. Interviews and observational data were used to explore the principles of garden sustainability with participants. Subsequent iterative thematic analysis informed development of a set of gardening sustainability principles. RESULTS: Principles of sustainability included effective garden planning; community autonomy, consultation and engagement; growing community vetted crops; employing long-term, effective, culturally sensitive managers; long-term, transparent funding organisations and cycles; garden integration into existing food supply chains; culturally appropriate employment arrangements; and physical aspects of successful gardening. CONCLUSIONS: This work uniquely consults gardeners, managers and Aboriginal and non-Aboriginal people of both genders in the largest reported study of its type, resulting in new and expanded findings, particularly including new social factors for gardening success. IMPLICATIONS: Expanding the understanding of what makes gardens work to include the important social factors identified here may have merit.

WITHDRAWN: Hybrid Procedure (Endo/Epicardial) Versus Standard Manual Ablation in Patients Undergoing Ablation of Longstanding Persistent Atrial Fibrillation: Results from a Single Center.

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