Anaesthetic Aspects of Implanting Diaphragmatic Pacing in Patients with Spinal Cord Injury

Some patients with high cervical spinal cord injury are largely or completely dependent on mechanical ventilator support. Diaphragmatic phrenic nerve pacing is a new technique that offers some patients greater independence from mechanical ventilation. In selected patients, electrodes are placed on the abdominal side of the diaphragm via laparoscopy. An external pacing box provides the pacing stimulus. We report our experience with four patients with spinal cord injury in a pilot project, presenting for laparoscopic insertion of diaphragmatic phrenic nerve pacing leads inserted. The surgery took about two hours and diaphragmatic mapping precluded muscle relaxants. We used desflurane with remifentanil for maintenance. Apart from transferring the patients to and from their usual ventilators, other anaesthesia issues were difficult venous and arterial access for lines and long-term tracheostomies with no cuff or cuffs filled with water. While hypotension was a frequent problem, one patient also developed intraoperative hypertension secondary to autonomic dysreflexia. Preoperative testing predicted pacing outcome with three of the four patients having successful pacing with tidal volumes of up to 10 ml/kg at the end of surgery. This initial Australian experience may lead to greater use of the technique.

A comparison of overall and disease-specific survivals following adjuvant radiotherapy with neo-adjuvant radiotherapy for rectal cancer

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Background: Preoperative radiotherapy is the preferred treatment for stage II-III rectal cancer. This arose following publication of the results of the German Rectal Cancer Study Group. It demonstrated a statistically significantly reduced local recurrence rate, and reduced toxicity for preoperative treatment compared with postoperative treatment. However, it failed to demonstrate improved overall survival. This study used the Surveillance, Epidemiology, and End Results (SEER) Program to compare overall and disease specific survival in rectal cancer patients treated with preoperative versus those receiving postoperative radiotherapy. Methods: 14,553 patients were identified with stage II-III rectal cancer, treated with either preoperative (5,136 patients) or postoperative radiotherapy (9,417 patients). Kaplan-Meier survival analyses and Cox multivariate analyses were used to compare 5 and 10 year overall and disease specific survival rates. Cause of death (COD) recorded as ‘Rectum and Rectosigmoid Junction’ was used to calculate rectal-specific survival. CODs recorded as ‘Colon excluding Rectum’ and ‘Rectum and Rectosigmoid Junction’ were used for colorectal-specific survival. Results: Kaplan-Meier analysis failed to demonstrate any statistical significant differences in survival figures. Cox multivariate analysis returned hazard ratios for overall survival of 1.207 (95% CI 1.122 - 1.298) and 1.180 (95% CI 1.103 - 1.263) at 5 and 10 years respectively for preoperative radiotherapy when compared with postoperative radiotherapy. For rectal-specific survival, 5 and 10 year hazard ratios of 1.381 (95% CI 1.239 - 1.539) and 1.342 (95% CI 1.210 - 1.489) respectively were obtained. Colorectal-specific survival returned 5 and 10 year hazard ratios of 1.222 (95% CI 1.124 - 1.329) and 1.193 (95% CI 1.101–1.292) respectively. Conclusions: Preoperative radiotherapy is the preferred treatment for stages II-III rectal cancer. This is because of its decreased risk of local recurrence and more optimal toxicity profile. However, this study suggests that preoperative radiotherapy is associated with poorer survival when compared with postoperative radiotherapy in the treatment of stage II-III rectal cancer.

No significant financial relationships to disclose.

Investigation of chromosome 1q reveals differential expression of members of the S100 family in clinical subgroups of intracranial paediatric ependymoma

Gain of 1q is one of the most common alterations in cancer and has been associated with adverse clinical behaviour in ependymoma. The aim of this study was to investigate this region to gain insight into the role of 1q genes in intracranial paediatric ependymoma. To address this issue we generated profiles of eleven ependymoma, including two relapse pairs and seven primary tumours, using comparative genome hybridisation and serial analysis of gene expression. Analysis of 656 SAGE tags mapping to 1q identified CHI3L1 and S100A10 as the most upregulated genes in the relapse pair with de novo 1q gain upon recurrence. Moreover, three more members of the S100 family had distinct gene expression profiles in ependymoma. Candidates (CHI3L1, S100A10, S100A4, S100A6 and S100A2) were validated using immunohistochemistry on a tissue microarray of 74 paediatric ependymoma. In necrotic cases, CHI3L1 demonstrated a distinct staining pattern in tumour cells adjacent to the areas of necrosis. S100A6 significantly correlated with supratentorial tumours (P<0.001) and S100A4 with patients under the age of 3 years at diagnosis (P=0.038). In conclusion, this study provides evidence that S100A6 and S100A4 are differentially expressed in clinically relevant subgroups, and also demonstrates a link between CHI3L1 protein expression and necrosis in intracranial paediatric ependymoma.

Phospholipase C-beta1 knockout mice exhibit endophenotypes modeling schizophrenia which are rescued by environmental enrichment and clozapine administration

Phospholipase C-beta1 (PLC-beta1) is a rate-limiting enzyme implicated in postnatal-cortical development and neuronal plasticity. PLC-beta1 transduces intracellular signals from specific muscarinic, glutamate and serotonin receptors, all of which have been implicated in the pathogenesis of schizophrenia. Here, we present data to show that PLC-beta1 knockout mice display locomotor hyperactivity, sensorimotor gating deficits as well as cognitive impairment. These changes in behavior are regarded as endophenotypes homologous to schizophrenia-like symptoms in rodents. Importantly, the locomotor hyperactivity and sensorimotor gating deficits in PLC-beta1 knockout mice are subject to beneficial modulation by environmental enrichment. Furthermore, clozapine but not haloperidol (atypical and typical antipsychotics, respectively) rescues the sensorimotor gating deficit in these animals, suggesting selective predictive validity. We also demonstrate a relationship between the beneficial effects of environmental enrichment and levels of M1/M4 muscarinic acetylcholine receptor binding in the neocortex and hippocampus. Thus we have demonstrated a novel mouse model, displaying disruption of multiple postsynaptic signals implicated in the pathogenesis of schizophrenia, a relevant behavioral phenotype and associated gene-environment interactions.

Prevalence and risk factors for common vision problems in children: data from the ALSPAC study

OBJECTIVE

To estimate the distribution and predictors of some common visual problems (strabismus, amblyopia, hypermetropia) within a population-based cohort of children at the age of 7 years.

METHODS

Children participating in a birth cohort study were examined by orthoptists who carried out cover/uncover, alternate cover, visual acuity and non-cycloplegic refraction tests. Prospectively collected data on potential risk factors were available from the study.

RESULTS

Data were available for 7825 seven-year-old children. 2.3% (95% CI 2.0% to 2.7%) had manifest strabismus, 3.6% (95% CI 3.3% to 4.1%) had past/present amblyopia, and 4.8% (95% CI 4.4% to 5.3%) were hypermetropic. Children from the lowest occupational social class background were 1.82 (95% CI 1.03% to 3.23%) times more likely to be hypermetropic than children from the highest social class. Amblyopia (p = 0.089) and convergent strabismus (p = 0.066) also tended to increase as social class decreased.

CONCLUSIONS

Although strabismus has decreased in the UK, it and amblyopia remain common problems. Children from less advantaged backgrounds were more at risk of hypermetropia and to a lesser extent of amblyopia and convergent strabismus. Children's eye-care services may need to take account of this socio-economic gradient in prevalence to avoid inequity in access to care.

Multiscale Design of Vascular Plates

Inspired by actuation mechanisms in plant structures and motivated by recent advances in electro-chemically driven micro-pumps, this paper is concerned with a novel concept for active materials based on distributed hydraulic actuation. Due to the similarity of the actuation principles seen in plants undergoing nastic motion, we refer to this class of active materials as nastic materials. We present a mechanical modeling approach for nastic materials representing the effects of pressure generation and fluid transport by incompressible eigenstrains. This model is embedded into a two-level macro/micro topology optimization procedure. On a macroscopic level, the integration of nastic material into a structural system is optimized. The placement and distribution of nastic material on a flexible substrate are optimized to generate target displacement and force distributions. On a microscopic level, the stress and strain generation is tailored to desired macroscopic material properties by optimizing the layout of vascular fluid channels embedded in an elastic matrix. For the layout optimization of vascular fluid channels, a novel topology optimization procedure is presented that models the effects of pressure along the fluid channels via an analogy with thermal conduction and convection. For this purpose an auxiliary heat transfer problem is solved. The macro-scale optimization procedure is studied for plate structures patterned by nastic materials in order to generate target bending and twist deformations. The results show the significant differences of the optimal distributions of active material depending on the strain model used for representing the actuation concept. The micro-scale vascular design methodology is verified with plane-stress examples. The results show that the layout of fluid channels can be optimized such that target strains are generated.

Proinflammatory proteases liberate a discrete high-affinity functional FPRL1 (CCR12) ligand from CCL23

Most chemokines have been found to bind to and signal through single or highly related chemokine receptors. However, a single chemokine protein, a processed form of the alternatively spliced CCL23 (CKbeta8/MPIF-1) gene product, potently engages both the "classical" chemokine receptor CCR1, as well as FPRL1, a type of pattern recognition receptor on innate immune cells. However, the mechanism by which the alternative form of CCL23 is processed is unknown. In this study, we show that proteases associated with inflammation cleave CCL23 immediately N-terminal to the 18-residue domain encoded by the alternatively spliced nucleotides, resulting in potent CCR1 and FPRL1 activity. The proteases also cleave CCL23 immediately C-terminal to the inserted domain, producing a typical CC chemokine "body" containing even further-increased CCR1 potency and a released approximately 18-aa peptide with full FPRL1 activity but no activity for CCR1. This peptide, which we term SHAAGtide, is by itself an attractant of monocytes and neutrophils in vitro, recruits leukocytes in vivo, and is 50- to 100-fold more potent than all other natural agents posited to act on FPRL1. The appearance of SHAAGtide appears to be transient, however, as the proinflammatory proteases subsequently cleave within the peptide, abolishing its activity for FPRL1. The sequential activation of a transient FPRL1 ligand and a longer-lived CCR1 ligand within a single chemokine may have important consequences for the development of inflammation or the link between innate and adaptive immunity.