BMIT facility at the Canadian Light Source: Advances in X-ray phase-sensitive imaging

The BioMedical Imaging and Therapy (BMIT) facility [1,2] located at the Canadian Light Source, provides synchrotron-specific imaging and radiation therapy capabilities. There are two separate beamlines used for experiments: the bending magnet (05B1-1) and the insertion device (05ID-2) beamline. The bending magnet beamline provides access to monochromatic beam spanning a spectral range of 15-40keV, and the beam is 240mm wide in the POE-2 experimental hutch. Users can also perform experiments with polychromatic (pink) beam. The insertion device beamline was officially opened for general user program in 2015. The source for the ID beamline is a multi-pole, superconducting 4.3T wiggler. The high field gives a critical energy over 20keV. The optics hutches prepare a beam that is 220mm wide in the last experimental hutch SOE-1. The monochromatic spectral range spans 25-150+keV. Several different X-ray detectors are available for both beamlines, with resolutions ranging from 2μm to 200μm. BMIT provides a number of imaging techniques including standard absorption X-ray imaging, K-edge subtraction imaging (KES), in-line phase contrast imaging (also known as propagation based imaging, PBI) and Diffraction Enhanced Imaging/Analyzer Based Imaging (DEI/ABI), all in either projection or CT mode. PBI and DEI/ABI are particularly important tools for BMIT users since these techniques enable visualization of soft tissue and allow for low dose imaging.

Development of an estuarine assessment scheme for the management of a highly urbanised catchment/estuary system, Sydney estuary, Australia

As coastal populations increase, considerable pressures are exerted on estuarine environments. Recently, there has been a trend towards the development and use of estuarine assessment schemes as a decision support tool in the management of these environments. These schemes offer a method by which complex environmental data is converted into a readily understandable and communicable format for informed decision making and effective distribution of limited management resources. Reliability and effectiveness of these schemes are often limited due to a complex assessment framework, poor data management and use of ineffective environmental indicators. The current scheme aims to improve reliability in the reporting of estuarine condition by including a concise assessment framework, employing high-value indicators and, in a unique approach, employing fuzzy logic in indicator evaluation. Using Sydney estuary as a case study, each of the 15 sub-catchment/sub-estuary systems were assessed using the current scheme. Results identified that poor sediment quality was a significant issue in Blackwattle/Rozelle Bay, Iron Cove and Hen and Chicken Bay while poor water quality was of particular concern in Duck River, Homebush Bay and the Parramatta River. Overall results of the assessment scheme were used to prioritise the management of each sub-catchment/sub-estuary assessed with Blackwattle/Rozelle Bay, Homebush Bay, Iron Cove and Duck River considered to be in need of a high priority management response. A report card format, using letter grades, was employed to convey the results of the assessment in a readily understood manner to estuarine managers and members of the public. Letter grades also provide benchmarking and performance monitoring ability, allowing estuarine managers to set improvement targets and assesses the effectiveness of management strategies. The current assessment scheme provides an effective, integrated and consistent assessment of estuarine health and provides an effective decision support tool to maximise the efficient distribution of limited management resources.

Impact of hypothermic preservation on tissue yield and viability in pig pancreata

INTRODUCTION

Chronic shortage of quality human cadaveric pancreata limits islet transplantation. Porcine islet xenotransplantation is being explored to increase the donor pool. For clinical-ready islets, centralized animal husbandry, Current Good Manufacturing Practice-regulated processing facilities, and organ transportation support are required. Amount of cold ischemia time (CIT) before isolation significantly affects transplantation. The goal of this study was to determine the maximum safe CIT of whole pancreata before islet isolation.

MATERIALS AND METHODS

Pancreata were rapidly removed from Yorkshire pigs (age, 14-22 days) and stored in modified University of Wisconsin solution or in EuroCollins solution at 4(°)C. Pancreata were processed with <1 hour CIT (control) or stored for 4 or 12 hours before isolation. Islet yield and percent purity and viability were determined after 7 days of in vitro tissue culture and maturation. Samples from nonprocessed pancreata were collected and snap-frozen in liquid nitrogen at 0, 3, 6, 9, 12, 15, and 24 hours of preservation, then analyzed for adenosine diphosphate/adenosine triphosphate ratio as a measure of tissue energetics.

RESULTS

Up to 12 hours in cold storage had no significant impact on overall islet yield after 7 days of in vitro culture compared with controls; islet yield at the end of the maturation process was 28,700 ± 500 islet equivalents per pancreas (mean ± SEM control yield, 30,300 ± 900 islet equivalents per pancreas); islet purity was 75 ± 5% compared with 74 ± 5% in controls. Islet viability was significantly reduced at 12 hours compared with controls (80 ± 6% vs 96 ± 5%; P < .05). The tissue adenosine diphosphate/adenosine triphosphate ratio was maintained within the first 6 hours (1.6 ± 0.1 to 1.8 ± 0.2; P = NS) but was markedly increased during the 24-hour study (3.3 ± 0.1 at 24 hours), indicating a progressive loss of adenosine triphosphate tissue stores.

CONCLUSIONS

Young pig pancreata can be hypothermically stored for up to 12 hours without affecting islet yield and purity; however, islet viability is reduced. These data highlight the need for uniform shipping parameters to standardize islet quality, ideally with CIT <6 hours.

A Descriptive Physical Profile of Western Australian Male Paramedics

Introduction The purpose of this investigation was to evaluate the physical characteristics of a group of West Australian male paramedics. Methods Data was collected from conventional (CO) (n=18) and special operations (SO) (n=11) officers undergoing occupational performance evaluations as contracted by St. John Ambulance Australia to an external independent third party. Using a series of field-based physical conditioning tests, aerobic capacity (multistage shuttle run test), body composition (skinfolds), flexibility (sit-and-reach test), muscular strength (5 stage abdominal and grip strength), muscular endurance (sit-ups, push-ups and chin-ups in 60 seconds (s)), power (vertical jump height), and anaerobic capacity/agility using the Bangsbo agility test were examined. Results The average predicted aerobic capacity of all officers was 45.8±5.2 ml·kg·min-1 (mean ± SD). Mean rating of abdominal strength was 4±1 and mean grip strength was 52±9 kg. The maximum number of sit-ups, push-ups and chin-ups performed in 60 s was 21±11, 40±12 and 7±5, respectively. Significantly more push-ups were completed for SO than for CO. Percentage body fat was significantly lower for SO than for CO. Fatigue index score (Bangsbo test) were significantly lower for SO than for CO. Conclusion The physical fitness profile of our sample indicated above normal levels of aerobic capacity, local muscle endurance and muscle strength, which likely contributes to workplace performance competency. However the fitness profile highlighted a potential deficiency in anaerobic capacity. Paramedics may benefit from a physical conditioning program with emphasis on their ability to operate at a greater functional capacity for higher repeated near maximal efforts.

Safety and tolerability of collagenase Clostridium histolyticum and fasciectomy for Dupuytren's contracture

Safety was evaluated for collagenase Clostridium histolyticum (CCH) based on 11 clinical trials (N = 1082) and compared with fasciectomy data in a structured literature review of 48 European studies (N = 7727) for treatment of Dupuytren's contracture. Incidence of adverse events was numerically lower with CCH vs. equivalent complications from fasciectomy (median [range] incidence), including nerve injury (0% vs. 3.8% [0%-50+%]), neurapraxia (4.4% vs. 9.4% [0%-51.3%]), complex regional pain syndrome (0.1% vs. 4.5% [1.3%-18.5%]) and arterial injury (0% vs. 5.5% [0.8%-16.5%]). Tendon injury (0.3% vs. 0.1% [0%-0.2%]), skin injury (16.2% vs. 2.8% [0%-25.9%]) and haematoma (77.7% vs. 2.0% [0%-25%]) occurred at a numerically higher incidence with CCH than surgery. Adverse events in CCH trials not reported after fasciectomy included peripheral oedema; extremity pain; injection site pain, haemorrhage and swelling; tenderness; pruritus and lymphadenopathy. CCH-related adverse events were reported as predominantly injection-related and transient. These results may support clinical decision-making for treatment of Dupuytren's contracture.

Effect of maraviroc on non-R5 tropic HIV-1: refined analysis of subjects from the phase IIb study A4001029

We characterized maraviroc susceptibility of dual/mixed tropic viruses from subjects enrolled onto phase IIb study A4001029. Maraviroc baseline plasma samples from 13 multidrug-experienced subjects were sequenced and the HIV-1-env gene cloned into pNL4.3Δenv to obtain recombinant viruses. The V3 region was sequenced by the Sanger method and ultradeep sequencing. By analysing subjects having a weighted optimized background therapy susceptibility (wOBT) score of <1, 3/7 subjects were characterized by good in vivo and in vitro response to maraviroc therapy. Molecular docking simulations allowed us to rationalize the maraviroc susceptibility of dual/mixed tropic viruses. A subset of subjects with dual/mixed tropic viruses responded to maraviroc. Further investigations are warranted of CCR5 antagonists in subjects carrying dual/mixed tropic virus that explore the feasible use of maraviroc in subjects that is potentially larger than those infected with a pure R5 virus.

Function and viability of human islets encapsulated in alginate sheets: in vitro and in vivo culture

Islet encapsulation offers an immune system barrier for islet transplantation, and encapsulation within an alginate sheetlike structure offers the ability to be retrievable after transplanted. This study aims to show that human islets encapsulated into islet sheets remain functional and viable after 8 weeks in culture or when transplanted into the subcutaneous space of rats. Human islets were isolated from cadaveric organs. Dissociation and purification were done using enzymatic digestion and a continuous Ficoll-UWD gradient. Purified human islets were encapsulated in alginate sheets. Human Islet sheets were either kept in culture, at 37°C and 5% CO(2), or transplanted subcutaneously into Lewis rats. After 1, 2, 4, and 8 weeks, the human islet sheets were retrieved from the rats and assessed. The viability of the sheets was measured using fluorescein diacetate (FDA)/propidium iodide (PI), and function was measured through glucose-stimulated insulin release, in which the sheets were incubated for an hour in low-glucose concentration (2.8 mmol/L) and then high (28 mmol/L), then high (28 mmol/L) plus 3-isobutyl-1-methylxanthine (50 μm). Human islet sheets remained both viable, above 70%, and functional, with a stimulation index (insulin secretion in high glucose divided by insulin secretion in low glucose) above 1.5, over 8 weeks of culture or subcutaneous transplantation. Islet transplantation continues to make advances in the treatment of type 1 diabetes. These preliminary results suggest that encapsulated islets sheets can survive and maintain islet viability and function in vivo, within the subcutaneous region.

Studies of the conductance changes induced in bimolecular lipid membranes by alamethicin

The addition of alamethicin to lecithin bilayers results in both voltage-dependent and voltage-independent conductance changes. In the voltage-dependent region, the slope of the conductance-voltage curve varies with the charge of the cation present in the aqueous phase. It may be shown that these effects may be accounted for by a kinetic model which incorporates the following suppositions: (1) alamethicin molecules are adsorbed at the membrane-water interface; (2) the effect of the potential is to redistribute alamethicin-cation complexes between the two surfaces of the bilayer; (3) conduction through the bilayer follows the surface interaction of approximately six alamethicin molecules; and (4) there is an assymetry in the rate constants for corresponding transitions on opposite sides of the bilayer.The effects of alamethicin are found to be approximately the same at neutral and low pH and are unchanged when bilayers are formed from phosphatidyl serine rather than lecithin. These findings are discussed in relation to current hypotheses of the molecular nature of the conduction mechanism.

Quantitative performance measurements of bent crystal Laue analyzers for X-ray fluorescence spectroscopy

Third-generation synchrotron radiation sources pose difficult challenges for energy-dispersive detectors for XAFS because of their count rate limitations. One solution to this problem is the bent crystal Laue analyzer (BCLA), which removes most of the undesired scatter and fluorescence before it reaches the detector, effectively eliminating detector saturation due to background. In this paper experimental measurements of BCLA performance in conjunction with a 13-element germanium detector, and a quantitative analysis of the signal-to-noise improvement of BCLAs are presented. The performance of BCLAs are compared with filters and slits.

Genetic mixed-stock analysis of Atlantic sturgeon Acipenser oxyrinchus oxyrinchus in a heavily exploited marine habitat indicates the need for routine genetic monitoring

Although a previous genetic mixed-stock analysis (gMSA) conducted in the early 1990s showed that marine-captured New York Bight Atlantic sturgeon Acipenser oxyrinchus oxyrinchus almost exclusively originated from the Hudson River, fish from southern U.S. rivers were well represented within this contemporary sample (n = 364 fish), at least during the autumn. Widely distributed spawning stocks are therefore exposed to heavy fishing activity and habitat degradation in this relatively small area, illustrating the need for spatial management across multiple management jurisdictions and routine gMSA to account for temporal change.