Presynaptic T-Type Ca²⁺ Channels Modulate Dendrodendritic Mitral–Mitral and Mitral–Periglomerular Connections in Mouse Olfactory Bulb

Mitral cells express low-voltage activated Cav3.3 channels on their distal apical tuft dendrites (McKay et al., 2006; Johnston and Delaney, 2010). They also discharge Na -dependent dendritic action potentials and release glutamate from these dendrites. Around resting membrane potentials, between 65 and 50 mV, Cav3.x channels are a primary determinant of cytoplasmic [Ca 2 ]. In this study using C57 mice, we present evidence that subthreshold Cav3.x-mediated Ca 2 influx modulates action potential evoked transmitter release and directly drives asynchronous release from distal tuft dendrites. Presynaptic hyperpolarization and selective block of Cav3.x channels with Z941 (Tringham et al., 2012) reduce mitral-to-mitral EPSP amplitude, increase the coefficient of variation of EPSPs, and increase paired-pulse ratios, consistent with a reduced probability of transmitter release. Both hyperpolarization and Cav3.x channel blockade reduce steady-state cytoplasmic [Ca 2 ] in the tuft dendrite without reducing action potential evoked Ca 2 influx, suggesting that background [Ca 2 ] modulates evoked release. We demonstrate that Cav3.x-mediated Ca 2 influx from even one mitral cell at membrane potentials between 65 and 50 mV is sufficient to produce feedback inhibition from periglomerular neurons. Deinactivation of Cav3.x channels by hyperpolarization increases T-type Ca 2 influx upon repolarization and increases feedback inhibition to produce subthreshold modulation of the mitral-periglomerular reciprocal circuit

Measuring the health impact of human rights violations related to Australian asylum policies and practices: A mixed methods study

This article has been made available through the Brunel Open Access Publishing Fund - Copyright @ 2009 Johnston et al.BACKGROUND: Human rights violations have adverse consequences for health. However, to date, there remains little empirical evidence documenting this association, beyond the obvious physical and psychological effects of torture. The primary aim of this study was to investigate whether Australian asylum policies and practices, which arguably violate human rights, are associated with adverse health outcomes. METHODS: We designed a mixed methods study to address the study aim. A cross-sectional survey was conducted with 71 Iraqi Temporary Protection Visa (TPV) refugees and 60 Iraqi Permanent Humanitarian Visa (PHV) refugees, residing in Melbourne, Australia. Prior to a recent policy amendment, TPV refugees were only given temporary residency status and had restricted access to a range of government funded benefits and services that permanent refugees are automatically entitled to. The quantitative results were triangulated with semi-structured interviews with TPV refugees and service providers. The main outcome measures were self-reported physical and psychological health. Standardised self-report instruments, validated in an Arabic population, were used to measure health and wellbeing outcomes. RESULTS: Forty-six percent of TPV refugees compared with 25% of PHV refugees reported symptoms consistent with a diagnosis of clinical depression (p = 0.003). After controlling for the effects of age, gender and marital status, TPV status made a statistically significant contribution to psychological distress (B = 0.5, 95% CI 0.3 to 0.71, p </= 0.001) amongst Iraqi refugees. Qualitative data revealed that TPV refugees generally felt socially isolated and lacking in control over their life circumstances, because of their experiences in detention and on a temporary visa. This sense of powerlessness and, for some, an implicit awareness they were being denied basic human rights, culminated in a strong sense of injustice. CONCLUSION: Government asylum policies and practices violating human rights norms are associated with demonstrable psychological health impacts. This link between policy, rights violations and health outcomes offers a framework for addressing the impact of socio-political structures on health.This research was supported by an Australian National and Medical Research Council PhD Scholarship (N. 251782) and a Victorian Health Promotion Foundation research grant (No. 2002-0280)

No imminent quantum supremacy by boson sampling

It is predicted that quantum computers will dramatically outperform their conventional counterparts. However, large-scale universal quantum computers are yet to be built. Boson sampling is a rudimentary quantum algorithm tailored to the platform of photons in linear optics, which has sparked interest as a rapid way to demonstrate this quantum supremacy. Photon statistics are governed by intractable matrix functions known as permanents, which suggests that sampling from the distribution obtained by injecting photons into a linear-optical network could be solved more quickly by a photonic experiment than by a classical computer. The contrast between the apparently awesome challenge faced by any classical sampling algorithm and the apparently near-term experimental resources required for a large boson sampling experiment has raised expectations that quantum supremacy by boson sampling is on the horizon. Here we present classical boson sampling algorithms and theoretical analyses of prospects for scaling boson sampling experiments, showing that near-term quantum supremacy via boson sampling is unlikely. While the largest boson sampling experiments reported so far are with 5 photons, our classical algorithm, based on Metropolised independence sampling (MIS), allowed the boson sampling problem to be solved for 30 photons with standard computing hardware. We argue that the impact of experimental photon losses means that demonstrating quantum supremacy by boson sampling would require a step change in technology.Comment: 25 pages, 9 figures. Comments welcom

Phase transitions in biological membranes

Native membranes of biological cells display melting transitions of their lipids at a temperature of 10-20 degrees below body temperature. Such transitions can be observed in various bacterial cells, in nerves, in cancer cells, but also in lung surfactant. It seems as if the presence of transitions slightly below physiological temperature is a generic property of most cells. They are important because they influence many physical properties of the membranes. At the transition temperature, membranes display a larger permeability that is accompanied by ion-channel-like phenomena even in the complete absence of proteins. Membranes are softer, which implies that phenomena such as endocytosis and exocytosis are facilitated. Mechanical signal propagation phenomena related to nerve pulses are strongly enhanced. The position of transitions can be affected by changes in temperature, pressure, pH and salt concentration or by the presence of anesthetics. Thus, even at physiological temperature, these transitions are of relevance. There position and thereby the physical properties of the membrane can be controlled by changes in the intensive thermodynamic variables. Here, we review some of the experimental findings and the thermodynamics that describes the control of the membrane function.Comment: 23 pages, 15 figure

What are we measuring? A critique of range of motion methods currently in use for Dupuytren's disease and recommendations for practice

Background: Range of motion is the most frequently reported measure used in practice to evaluate outcomes. A goniometer is the most reliable tool to assess range of motion yet, the lack of consistency in reporting prevents comparison between studies. The aim of this study is to identify how range of motion is currently assessed and reported in Dupuytren’s disease literature. Following analysis recommendations for practice will be made to enable consistency in future studies for comparability. This paper highlights the variation in range of motion reporting in Dupuytren’s disease. Methods: A Participants, Intervention, Comparison, Outcomes and Study design format was used for the search strategy and search terms. Surgery, needle fasciotomy or collagenase injection for primary or recurrent Dupuytren’s disease in adults were included if outcomes were monitored using range of motion to record change. A literature search was performed in May 2013 using subject heading and free-text terms to also capture electronic publications ahead of print. In total 638 publications were identified and following screening 90 articles met the inclusion criteria. Data was extracted and entered onto a spreadsheet for analysis. A thematic analysis was carried out to establish any duplication, resulting in the final range of motion measures identified. Results: Range of motion measurement lacked clarity, with goniometry reportedly used in only 43 of the 90 studies, 16 stated the use of a range of motion protocol. A total of 24 different descriptors were identified describing range of motion in the 90 studies. While some studies reported active range of motion, others reported passive or were unclear. Eight of the 24 categories were identified through thematic analysis as possibly describing the same measure, ‘lack of joint extension’ and accounted for the most frequently used. Conclusions: Published studies lacked clarity in reporting range of motion, preventing data comparison and meta-analysis. Percentage change lacks context and without access to raw data, does not allow direct comparison of baseline characteristics. A clear description of what is being measured within each study was required. It is recommended that range of motion measuring and reporting for Dupuytren’s disease requires consistency to address issues that fall into 3 main categories:- Definition of terms Protocol statement Outcome reportin

Apicotomy: a root apical fracture for surgical treatment of impacted upper canines

Impacted canines, due to systemic or local factors, represent a frequent problem in most populations. Surgical intervention usually involves exposure for spontaneous eruption, exposure for orthodontic traction or extraction. The author presents the apicotomy technique, which has been successfully used during the past twenty years for conservative intervention in cases of impacted upper canines with dilaceration or apical root-ankylosis. This original method involves surgical fracture of the root apex, followed by orthodontic traction of the corono-radicular region

Optimal functional outcome measures for assessing treatment for Dupuytren's disease: A systematic review and recommendations for future practice

This article is available through the Brunel Open Access Publishing Fund. Copyright © 2013 Ball et al.; licensee BioMed Central Ltd.Background: Dupuytren's disease of the hand is a common condition affecting the palmar fascia, resulting in progressive flexion deformities of the digits and hence limitation of hand function. The optimal treatment remains unclear as outcomes studies have used a variety of measures for assessment. Methods: A literature search was performed for all publications describing surgical treatment, percutaneous needle aponeurotomy or collagenase injection for primary or recurrent Dupuytren’s disease where outcomes had been monitored using functional measures. Results: Ninety-one studies met the inclusion criteria. Twenty-two studies reported outcomes using patient reported outcome measures (PROMs) ranging from validated questionnaires to self-reported measures for return to work and self-rated disability. The Disability of Arm, Shoulder and Hand (DASH) score was the most utilised patient-reported function measure (n=11). Patient satisfaction was reported by eighteen studies but no single method was used consistently. Range of movement was the most frequent physical measure and was reported in all 91 studies. However, the methods of measurement and reporting varied, with seventeen different techniques being used. Other physical measures included grip and pinch strength and sensibility, again with variations in measurement protocols. The mean follow-up time ranged from 2 weeks to 17 years. Conclusions: There is little consistency in the reporting of outcomes for interventions in patients with Dupuytren’s disease, making it impossible to compare the efficacy of different treatment modalities. Although there are limitations to the existing generic patient reported outcomes measures, a combination of these together with a disease-specific questionnaire, and physical measures of active and passive individual joint Range of movement (ROM), grip and sensibility using standardised protocols should be used for future outcomes studies. As Dupuytren’s disease tends to recur following treatment as well as extend to involve other areas of the hand, follow-up times should be standardised and designed to capture both short and long term outcomes

Evaluation of the current knowledge limitations in breast cancer research: a gap analysis

BACKGROUND A gap analysis was conducted to determine which areas of breast cancer research, if targeted by researchers and funding bodies, could produce the greatest impact on patients. METHODS Fifty-six Breast Cancer Campaign grant holders and prominent UK breast cancer researchers participated in a gap analysis of current breast cancer research. Before, during and following the meeting, groups in seven key research areas participated in cycles of presentation, literature review and discussion. Summary papers were prepared by each group and collated into this position paper highlighting the research gaps, with recommendations for action. RESULTS Gaps were identified in all seven themes. General barriers to progress were lack of financial and practical resources, and poor collaboration between disciplines. Critical gaps in each theme included: (1) genetics (knowledge of genetic changes, their effects and interactions); (2) initiation of breast cancer (how developmental signalling pathways cause ductal elongation and branching at the cellular level and influence stem cell dynamics, and how their disruption initiates tumour formation); (3) progression of breast cancer (deciphering the intracellular and extracellular regulators of early progression, tumour growth, angiogenesis and metastasis); (4) therapies and targets (understanding who develops advanced disease); (5) disease markers (incorporating intelligent trial design into all studies to ensure new treatments are tested in patient groups stratified using biomarkers); (6) prevention (strategies to prevent oestrogen-receptor negative tumours and the long-term effects of chemoprevention for oestrogen-receptor positive tumours); (7) psychosocial aspects of cancer (the use of appropriate psychosocial interventions, and the personal impact of all stages of the disease among patients from a range of ethnic and demographic backgrounds). CONCLUSION Through recommendations to address these gaps with future research, the long-term benefits to patients will include: better estimation of risk in families with breast cancer and strategies to reduce risk; better prediction of drug response and patient prognosis; improved tailoring of treatments to patient subgroups and development of new therapeutic approaches; earlier initiation of treatment; more effective use of resources for screening populations; and an enhanced experience for people with or at risk of breast cancer and their families. The challenge to funding bodies and researchers in all disciplines is to focus on these gaps and to drive advances in knowledge into improvements in patient care