The Usher Syndrome Type IIIB Histidyl-tRNA Synthetase Mutation Confers Temperature Sensitivity.

Histidyl-tRNA synthetase (HARS) is a highly conserved translation factor that plays an essential role in protein synthesis. HARS has been implicated in the human syndromes Charcot-Marie-Tooth (CMT) Type 2W and Type IIIB Usher (USH3B). The USH3B mutation, which encodes a Y454S substitution in HARS, is inherited in an autosomal recessive fashion and associated with childhood deafness, blindness, and episodic hallucinations during acute illness. The biochemical basis of the pathophysiologies linked to USH3B is currently unknown. Here, we present a detailed functional comparison of wild-type (WT) and Y454S HARS enzymes. Kinetic parameters for enzymes and canonical substrates were determined using both steady state and rapid kinetics. Enzyme stability was examined using differential scanning fluorimetry. Finally, enzyme functionality in a primary cell culture was assessed. Our results demonstrate that the Y454S substitution leaves HARS amino acid activation, aminoacylation, and tRNAHis binding functions largely intact compared with those of WT HARS, and the mutant enzyme dimerizes like the wild type does. Interestingly, during our investigation, it was revealed that the kinetics of amino acid activation differs from that of the previously characterized bacterial HisRS. Despite the similar kinetics, differential scanning fluorimetry revealed that Y454S is less thermally stable than WT HARS, and cells from Y454S patients grown at elevated temperatures demonstrate diminished levels of protein synthesis compared to those of WT cells. The thermal sensitivity associated with the Y454S mutation represents a biochemical basis for understanding USH3B.

Rapid and Efficient Stable Gene Transfer to Mesenchymal Stromal Cells Using a Modified Foamy Virus Vector.

Mesenchymal stromal cells (MSCs) hold great promise for regenerative medicine. Stable ex vivo gene transfer to MSCs could improve the outcome and scope of MSC therapy, but current vectors require multiple rounds of transduction, involve genotoxic viral promoters and/or the addition of cytotoxic cationic polymers in order to achieve efficient transduction. We describe a self-inactivating foamy virus vector (FVV), incorporating the simian macaque foamy virus envelope and using physiological promoters, which efficiently transduces murine MSCs (mMSCs) in a single-round. High and sustained expression of the transgene, whether GFP or the lysosomal enzyme, arylsulphatase A (ARSA), was achieved. Defining MSC characteristics (surface marker expression and differentiation potential), as well as long-term engraftment and distribution in the murine brain following intracerebroventricular delivery, are unaffected by FVV transduction. Similarly, greater than 95% of human MSCs (hMSCs) were stably transduced using the same vector, facilitating human application. This work describes the best stable gene transfer vector available for mMSCs and hMSCs.

Home visits and nursing home visits by early-career GPs: a cross-sectional study.

BACKGROUND: Home visits (HVs) and nursing home visits (NHVs) are accepted as core elements of general practice. There is concern regarding declining rates of HVs and an increasing demand for NHVs together with a perceived decreased willingness of younger GPs to provide these services. OBJECTIVES: To establish the prevalence and associations of recently vocationally qualified GPs ('graduates') performing HVs and NHVs. METHODS: A cross-sectional questionnaire-based study of recent (within 5 years) graduates of 3 of Australia's 17 regional general practice training programs. Outcome factors were performing, as part of current practice, HVs and NHVs. Factors associated with each outcome were assessed by logistic regression with graduate and current practice characteristics and vocational training experiences as independent variables. RESULTS: Of 230 responding graduates, 48.1% performed HVs and 40.6% performed NHVs in their current clinical GP role. Factors associated with both HVs and NHVs were participating in in-practice clinical teaching/supervision [odds ratios (ORs) 2.65 and 2.66], conducting HVs/NHVs during training (ORs 5.05 and 10.8) and working full-time (ORs for part-time work 0.20 and 0.29). Further associations with performing HVs were older GP age (compared to <36 years: ORs 3.65 for 36-40 and 2.53 for 41+), smaller practice size (OR 0.53 for larger practices), Australian undergraduate education (OR 0.31 for non-Australian) and greater number of years in their current practice as a qualified GP (OR 1.25 per year). CONCLUSIONS: Our findings of graduates' modest engagement with HVs and NHVs reinforce concerns regarding Australian general practice's capacity to accommodate the needs of an aging population.

Responding to registrars' in-consultation calls for assistance: Practical implications from the ReCeNT project.

BACKGROUND: General practice registrars in Australia are expected to identify and address their knowledge or skills gaps during consultations. The content and frequency of registrars seeking assistance and the factors that influence this have been studied for 84,723 consultations. Term 1 registrars asked their supervisor for help in 11.0% of consultations, but by term 4 this reduced to 1.2% of consultations. Assistance was most often for skin or musculoskeletal conditions, and more often about management than diagnosis. OBJECTIVE: This article discusses the implications of this information for Australian general practice training. DISCUSSION: Registrars asked their supervisors for assistance despite having ready access to electronic information. Practices can anticipate supervisor interruptions approximately every tenth registrar consultation. The greater input required by registrars from supervisors earlier in training should be acknowledged by more flexible standards and payments to practices. A priority for general practice supervisor professional development is how to teach the management of complex patients, dermatology and musculoskeletal medicine.

Maintaining capacity for in-practice teaching and supervision of students and general practice trainees: a cross-sectional study of early career general practitioners.

Objectives Expanding learner cohorts of medical students and general practitioner (GP) vocational trainees and the impending retirement of the 'baby boomer' GP cohort threaten the teaching and supervisory capacity of the Australian GP workforce. Engaging newly qualified GPs is essential to sustaining this workforce training capacity. The aim of the present study was to establish the prevalence and associations of in-practice clinical teaching and supervision in early career GPs. Methods The present study was a cross-sectional questionnaire-based study of recent (within 5 years) alumni of three of Australia's 17 regional general practice training programs. The outcome factor was whether the alumnus taught or supervised medical students, GP registrars or other learners in their current practice. Logistic regression analysis was used to establish associations of teaching and supervision with independent variables comprising alumnus demographics, current practice characteristics and vocational training experiences. Results In all, 230 alumni returned questionnaires (response rate 37.4%). Of currently practising alumni, 52.4% (95% confidence interval (CI) 45.6-59.0%) reported current teaching or supervisory activities. Factors significantly (P<0.05) associated with alumni currently undertaking in-practice clinical teaching and supervision were: Australian medical graduation (odds ratio (OR) for international graduates 0.36; 95% CI 0.14-0.92), working in a regional or remote area (OR 2.75; 95% CI 1.24-6.11) and currently undertaking nursing home visits, home visits or after-hours work (OR 2.01; CI 1.02-3.94). Conclusions Rural-urban and country-of-graduation differences in the engagement of early career GPs in practice-based apprenticeship-like teaching or training should inform strategies to maintain workforce training capacity. What is known about the topic? Projected changes in the demand for and supply of clinical teaching and supervision within Australian general practice will require greater uptake of teaching and supervision by recently qualified GPs to ensure sustainability of this teaching model. Although interest in and undertaking of teaching roles have been documented for GP or family medicine trainees, studies investigating the engagement in these clinical roles by GPs during their early post-training period are lacking. What does this paper add? This paper is the first to document the prevalence of teaching and supervision undertaken by early career GPs as part of their regular clinical practice. We also demonstrate associations of practice rurality, country of medical graduation and undertaking non-practice-based clinical roles with GPs' engagement in teaching and supervisory roles. What are the implications for practitioners? Establishing current teaching patterns of GPs enables appropriate targeting of new strategies to sustain an effective teaching and supervisory capacity within general practice. The findings of the present study suggest that exploring focused strategies to facilitate and support international medical graduates to engage in teaching during their vocational training, aided by focused supervisor support, may be of particular value.

Older patients' consultations in an apprenticeship model-based general practice training program: A cross-sectional study.

OBJECTIVE: To investigate older patients' encounters with general practice registrars (GPRs) to inform training and clinical practice. METHODS: Cross-sectional analysis of data from GPR consultations across five regional training providers in Australia. Data were analysed using simple and multiple logistic regression models. RESULTS: Our analysis included details of 118 831 consultations, 20 555 (17.6%, 95% CI 17.4-17.8) with patients aged ≥65 years. Older patient encounters had an increased likelihood of including chronic disease (OR 1.77, 95% CI 1.70, 1.86) and more problems (OR 1.24, 95% CI 1.20, 1.27). However, in-consultation information or advice was less likely to be sought (OR 0.92, 95% CI 0.88, 0.97), and consultations were briefer (OR 0.99, 95% CI 0.99, 1.00). CONCLUSION: Our results suggest relatively limited GPR exposure to older patients coupled with less complex consultations than expected. Solutions will need to be carefully constructed not only to increase caseloads, but also to address training and supervision concerns.

Factors associated with decline in physical functional health in a cohort of older women.

OBJECTIVE: To identify minimum criteria to assist the prediction of decline in physical health-related quality of life in the elderly. STUDY DESIGN AND SETTING: Participants were women from the Australian Longitudinal Study on Women's Health, who responded to three separate Surveys conducted in 1996 (when they were aged 70-75 years), 1999 and 2002. Using data from these Surveys, three categories were generated which described current physical health-related quality of life and future physical decline as measured by the physical component summary score (PCS) of the MOS SF-36 quality of life survey. RESULTS: Bivariate analyses reported a large number of variables significantly associated with physical decline (P < 0.001), including age, falls, number of diagnoses, symptoms, doctor visits and medications, days spent in hospital, body mass index, living arrangements and social support. Multivariate analyses, using decision tree analysis, identified three items which accurately predicted 76% of the women who would exhibit physical decline according to our definition. CONCLUSIONS: This study identified a number of variables that may be useful in clinical screening for vulnerability to physical decline.