Leading the rebirth of the rural obstetrician.

OBJECTIVES: To understand the factors influencing the decisions of rural general practitioners and GP registrars to practise obstetrics, and to understand the impact on these decisions of an innovative obstetric training and support program in the Gippsland region of Victoria. DESIGN, SETTING AND PARTICIPANTS: Qualitative approach using semistructured interviews conducted in July and August 2013 and inductive content analysis. Participants were identified from training records over the previous 5 years for the Gippsland GP obstetric training and support program. Two questions were posed during interviews: What challenges face rural GPs in practising obstetrics? What impact has the Gippsland GP obstetric program had on GP obstetric career decisions? RESULTS: Of 60 people invited to participate, 22 agreed. Interviews ranged in duration from 40 to 90 minutes. The major themes that emerged on the challenges facing rural GPs in practising obstetrics were isolation, work-life balance and safety. The major themes that emerged on the impact of the Gippsland GP obstetric program were professional support, structured training and effective leadership. CONCLUSION: Rural GP obstetricians are challenged by isolation, the impact of their job on work-life balance, and safety. The support, training and leadership offered by the Gippsland expanded obstetric training program helped doctors to deal with these challenges. The Gippsland model of training offers a template for GP obstetric procedural training programs for other rural settings.

Comparison of multislice and single-slice acquisitions for pulsed arterial spin labeling measurements of cerebral perfusion.

Multislice Q2TIPS is a widely used pulsed arterial spin labeling (PASL) technique for efficient and accurate quantification of cerebral blood flow (CBF). Slices are typically acquired inferior to superior from a tagging plane. Superior slices show signal loss greater than the loss expected from blood T1 decay. In order to assess the reasons for this additional signal loss, three single-slice acquisition studies were compared to multislice acquisition (six slices) in healthy volunteers. In Study 1 (n=8), the tagging plane was fixed in location, and the inversion time (TI2) was 1500 ms for each slice. For Study 2 (n=12), the tagging plane was fixed as in Study 1; however, TI2 increased as slices were acquired further from the tagging plane. In Study 3 (n=9), the tagging plane was kept adjacent to the imaging slice, and TI2 was 1500 ms for every slice. Gray matter (GM) and white matter (WM) signal-to-noise ratio (SNR) and CBF were measured per slice. GM SNR from single-slice acquisitions was significantly higher at slices 4-6 in Study 2 and at slices 2-6 in Study 3 compared to multislice acquisitions. Signal loss in distal slices of multislice acquisitions can be attributed to the destruction of tagged bolus in addition to blood T1 decay. If limited brain coverage is acceptable, perfusion images with greater SNR are achievable with limited slices and placement of the tagging region immediately adjacent to the site of interest.

Crystal structure of a new class of glutathione transferase from the model human hookworm nematode Heligmosomoides polygyrus.

The crystal structure of GST Nu2-2 (HpolGSTN2-2) from the model hookworm nematode Heligmosomoides polygyrus has been solved by the molecular replacement method and refined to a resolution of 1.71 A, providing the first structural data from a class of nematode-specific GSTs. By structural alignment with two Sigma class GSTs, glutathione could be rationally docked into the G-site of the enzyme. By comparing with all mammalian GST classes, a novel, long, and deep cleft was identified at the H-site, providing a potential site for ligand binding. This new GST class may support the establishment of infection parasitic nematodes by passively neutralizing chemical toxins derived from host environment. The structure serves as a starting point for structure-based drug/inhibitor design that would aim to selectively disrupt nematode chemical defenses.

Dynamic MRI (dMRI) as a guide to therapy in children and adolescents with persistent full thickness rectal prolapse: a single centre review.

INTRODUCTION: Full thickness rectal prolapse (FTRP) tends to be self-limiting in children and is usually managed expectantly. However, it may persist and therefore requires surgical correction. There is no consensus upon operative management, and no one procedure has uniformly good outcomes. The aim of this study was to determine whether pre-operative diagnostic dMRI findings might help identify the operative approach best suited to the anatomical abnormality of the individual child. METHODS: A retrospective review of ten children with persistent FTRP who had been evaluated pre-operatively with dMRI between 2002 and 2010 was performed. In this preliminary work, MRI findings were not used to direct surgical management. Data collected included: age at presentation, underlying medical conditions, timing and findings of dMRI (specifically, descent of rectum from pubococcygeal (PC) line on straining), timing and type of surgery, surgical outcomes, and length of follow-up. RESULTS: Ten children (two female) with a median age of 11 years 2 months (range 8-15 years) with FTRP refractory to conservative treatment underwent diagnostic pre-operative dMRI. Median perineal descent from PC line on straining during dMRI was 3.5 cm (range 1-4 cm). Three of the seven children with severe descent initially underwent a Delorme's procedure, and all required surgical revision. Five with severe descent and one with moderate descent achieved a cure following rectopexy. Two patients with mild descent underwent a Delorme's procedure. One achieved a cure, and the other developed recurrence. Of the ten patients, seven had no prolapse at the last clinic review, and three have persisting symptoms. Median follow-up was 3.5 years (range 1-6). CONCLUSION: The findings from this small study favour rectal suspension techniques for surgical management of moderate to severe perineal descent on dMRI. Delorme's procedure should only be applied to those with mild descent. Pre-operative dMRI assessment may have a potential role in guiding surgical intervention for children. However, future prospective studies will be required to confirm this assertion.

Lack of organ specific commitment of vagal neural crest cell derivatives as shown by back-transplantation of GFP chicken tissues.

Neural crest cells (NCC) are multipotent progenitors that migrate extensively throughout the developing embryo and generate a diverse range of cell types. Vagal NCC migrate from the hindbrain into the foregut and from there along the gastrointestinal tract to form the enteric nervous system (ENS), the intrinsic innervation of the gut, and into the developing lung buds to form the intrinsic innervation of the lungs. The aim of this study was to determine the developmental potential of vagal NCC that had already colonised the gut or the lungs. We used transgenic chicken embryos that ubiquitously express green fluorescent protein (GFP) to permanently mark and fate-map vagal NCC using intraspecies grafting. This was combined with back-transplantation of gut and lung segments, containing GFP-positive NCC, into the vagal region of a second recipient embryo to determine, using immunohistochemical staining, whether gut or lung NCC are competent of re-colonising both these organs, or whether their fate is restricted. Chick(GFP)-chick intraspecies grafting efficiently labelled NCC within the gut and lung of chick embryos. When segments of embryonic day (E)5.5 pre-umbilical midgut containing GFP-positive NCC were back-transplanted into the vagal region of E1.5 host embryos, the GFP-positive NCC remigrated to colonise both the gut and lungs and differentiated into neurons in stereotypical locations. However, GFP-positive lung NCC did not remigrate when back-transplanted. Our studies suggest that gut NCC are not restricted to colonising only this organ, since upon back-transplantation GFP-positive gut NCC colonised both the gut and the lung.

Heme transport and detoxification in nematodes: subproteomics evidence of differential role of glutathione transferases.

In contrast to their mammalian hosts, parasitic nematodes are heme auxotrophs and require pathways for the uptake and transport of exogenous heme for incorporation into hemoproteins. Phase II detoxification Nu-class glutathione transferase (GST) proteins have a proposed role as heme-binding ligandins in parasitic nematodes. The genome-verified free-living nematode Caenorhabditis elegans also cannot synthesize heme and is an ideal functional genomics model to delineate the role of individual nematode GSTs in heme trafficking and heme detoxification. In this study, C. elegans was exposed to externally controlled heme concentrations ranging from 20-fold suboptimal growth levels to 10-fold supra-optimal growth levels to mimic fluctuations in blood- and tissue-feeding parasitic cousins from the same nematode group. A new heme-responsive GST (GST-19) was identified by subproteomics approaches. Functional characterization of this and two other C. elegans GSTs revealed that they all have high affinity for heme compounds similar to mammalian soluble heme carrier proteins such as HBP23 ( K d approximately 10 (-8) M). In the genomics-predicted absence of orthologous mammalian soluble heme-binding proteins in nematodes, we propose that Nu-class GSTs are candidates in the cellular processing of heme compounds. Toxic heme binding may be coupled to enzymatic protection from its breakdown as several GSTs possess glutathione peroxidase activity.

Pulsed arterial spin labeling parameter optimization for an elderly population.

PURPOSE: To optimize pulsed arterial spin labeling (PASL) parameters for the elderly to take into account possible perfusion changes that occur in the brain with age. MATERIALS AND METHODS: Healthy young (N = 14, age range = 21-27 years) and elderly (N = 12, age range = 61-67 years) subjects were scanned using Q2TIPS (QUIPSS II with thin-slice TI, periodic saturation) with varying inversion times (TI(2)) at 1.5T. The difference signal (DeltaM), transit time (deltat), and cerebral blood flow (CBF) were calculated in segmented gray matter (GM). RESULTS: The young displayed more perfusion-weighted signal difference than the elderly at all TI(2)'s. The peak DeltaM occurred at TI(2) approximately 1300 msec and 1500 msec in the young and elderly groups, respectively. Qualitatively, intravascular signal was minimal in the younger group by TI(2) = 1500 msec, whereas a longer TI(2) of 1800 msec was needed to minimize this signal in the elderly. The transit time was approximately 100 msec longer in the elderly, and CBF was in the range of literature values. CONCLUSION: For acquiring perfusion-weighted images with minimal intravascular signal and adequate tissue signal for PASL studies of cerebral perfusion in the elderly, a longer inversion time is advantageous.

Evidence of glutathione transferase complexing and signaling in the model nematode Caenorhabditis elegans using a pull-down proteomic assay.

Phage display techniques using random peptide interactions have supported the role of mammalian glutathione transferase (GST) as part of a signalling pathway for both oxidative stress and an apoptosis pathway. Little is known about the interaction of nonmammalian GST with other proteins. GSTs have been implicated in the development of chronic nematode infections by neutralising cytotoxic products arising from host immune initiated reactive oxygen species (ROS) assault. In this study we attached one of the key GSTs expressed in the model nematode Caenorhabditis elegans to an affinity support matrix and directly identified major interacting proteins by two-dimensional electrophoresis and peptide mass fingerprinting before and following oxidative stress. Nematode GST does not appear to be a stand-alone enzyme and interacts with many types of proteins in both normal and ROS stress conditions. Pull-down proteomic presents a flexible, label free, rapid and economical assay without specialised ligand fishing equipment to identify protein binding partners.