3D analysis of CROMER (DAF) and a new antigen CRAG.

BACKGROUND: Cromer antigens are carried on decay accelerating factor (DAF, CD55), for which the crystal structure is available. We investigated two samples with an unidentified antibody to a high prevalence antigen and evaluate the location and characteristics of amino acids associated with antigens on the CD55 by 3D modelling. MATERIALS AND METHODS: Antigen typing and antibody identification were by standard methods. CD55 was sequenced, and Cromer variants were generated using the protein's crystal structure (1OK3, chain A). Antigen-associated residues and intraprotein interactions were investigated in 3D (Naccess, Protein Interactions Calculator). RESULTS: The antibody in the sample from a woman of Kashmiri descent was identified as anti-IFC (anti-CROM7). Her RBCs were negative for high-prevalence Cromer antigens including IFC. CD55 sequencing revealed a silent c.147G>A (p.Leu49=) and c.148G>T (p.Glu50Ter) changes, designated CROM*01N.05. The antibody in the sample from a woman of Greek ancestry was only compatible with IFC- RBCs but her RBCs were positive for known high-prevalence Cromer antigens. CD55 sequencing found she was homozygous for c.173A>G (p.Asp58Gly). The high prevalence antigen was named CRAG (ISBT CROM18 or 021018) and the allele designated CROM*01.-18. By 3D analysis, all known antigen-associated residues, including the new CRAG antigen, were exposed at the protein surface. Interactions between antigen-associated residues within the same CD55 domains were identified. DISCUSSION: Identification of antibodies to high prevalence Cromer antigens can be challenging. The surface exposure of antigen-associated residues likely accounts for their immunogenicity. 3D analysis of CD55 provides insight into previous serologic observations regarding the influence of some Cromer antigens on the expression of others.

Using videoed simulated clinical interaction to promote communication skills and reflective practice for overseas-born medical students.

This paper describes a teaching intervention designed to promote the clinical communications skills of overseas-born medical students through critical reflection on the practice of others. Using a staged process and a video recording of a simulated medical interaction it investigated the extent to which the participants were able to anticipate, identify and resolve the targeted communication issues, and demonstrate selected skills in a simulated interaction. Data comprised worksheet notes, transcriptions (group discussions) and completed questionnaires (ratings and comments). Analysis was thematic (worksheet notes, transcription, questionnaire feedback) and quantitative (questionnaire ratings). The results suggest the notion of reflective practice could be productively extended to take account of current developments in pedagogy and learning. This includes providing opportunities for students to share ideas, resolve differences and ambiguities, and address gaps in their communication skills as well as to apply learned concepts and receive targeted feedback. While the intervention specifically targeted overseas-born medical students, the approach described in the paper has potential for developing the communication skills of 'local' medical students and healthcare professionals more generally.

International medical students and migration: the missing dimension in Australian workforce planning?

OBJECTIVE: To investigate the potential contribution of international medical students at Australian universities to the Australian medical workforce. DESIGN, SETTING AND PARTICIPANTS: A prospective survey in 2006-2007 of 619 international medical students in their final 2 years of undergraduate- and graduate-entry medical courses across eight Australian universities, followed by a 2009 survey of 88 international medical graduates of the University of Melbourne (most of whom were respondents of the earlier survey), assessing the correlation between students' intended place of internship and their actual place of internship. MAIN OUTCOME MEASURES: The survey respondents' preferred internship location; the proportion of respondents who intended to remain in practice in Australia long term; and correlation between respondents' intended internship locations and actual placements in their first postgraduate year. RESULTS: Of the 619 international medical students surveyed in 2006, 358 (58%) responded. Most planned to undertake Australian internships and seek permanent-resident status, although a third were undecided about their long-term plans. Nationality was a highly significant variable. Most preferred city rather than regional or rural training locations and expressed interest in migrating to Australia. The 2009 survey of the University of Melbourne's 2008 medical graduates showed a high correlation between students' plans in their last two years of study and outcomes in their first postgraduate year, with 73% accepting Victorian internships for 2009. CONCLUSION: International medical students studying at Australian universities represent a substantial and highly acceptable medical workforce resource for Australia. Their requirement for internships needs to be considered in, and should influence, infrastructure planning.

A comparison of peritoneal equilibration tests performed 1 and 4 weeks after PD commencement.

OBJECTIVE: The aim of this study was to prospectively evaluate the ability of a peritoneal equilibration test (PET) performed in the first week of peritoneal dialysis (PD) to predict subsequent transport status, as determined by a PET at 4 weeks and >1 year after PD commencement. DESIGN: Prospective observational study of an incident PD cohort at a single center. SETTING: Tertiary-care institutional dialysis center. PARTICIPANTS: The study included 50 consecutive patients commencing PD at the Princess Alexandra Hospital between 25/2/2001 and 14/5/2003 (mean age 60.9 +/- 12.2 years, 54% male, 92% Caucasian, 38% diabetic). All patients were initially prescribed continuous ambulatory PD. MAIN MEASUREMENTS: Measurements performed during paired PETs included dialysate-to-plasma ratios of urea (D/P urea) and creatinine (D/P creatinine) at 4 hours, the ratio of dialysate glucose concentrations at 0 and 4 hours (D/D0 glucose), and drain volumes at 4 hours. RESULTS: When paired 1-week and 1-month PET data were analyzed, significant changes were observed in measured D/P urea (0.91 +/- 0.07 vs 0.94 +/- 0.07 respectively; p < 0.05), D/P creatinine (0.55 +/- 0.12 vs 0.66 +/- 0.11, p < 0.001), and D/D0 glucose (0.38 +/- 0.08 vs 0.36 +/- 0.10, p < 0.05). Using Bland-Altman analysis, the repeatability coefficients were 0.17, 0.20, and 0.13, respectively. Agreement between 1-week and 1-month PET measurements with respect to peritoneal transport category was moderate for D/D0 glucose (weighted kappa 0.52), but poor for D/P urea (0.30), D/P creatinine (0.35), and drain volumes (0.20). The PET measurements performed more than 1 year following PD commencement (n = 28) generally agreed closely with 1-month measurements, and poorly with 1-week measurements. CONCLUSIONS: Peritoneal transport characteristics change significantly within the first month of PD. PETs carried out during this time should be considered preliminary and should be confirmed by a PET 4 weeks later. Nevertheless, performing an early D/D0 glucose measurement at 1 week predicted ultimate transport status sufficiently well to facilitate early clinical decision-making about optimal PD modality while patients were still receiving PD training. On the other hand, the widespread practice of using measured drain volumes in the first week to predict ultimate transport category is highly inaccurate and not recommended.

Increases in peritoneal small solute transport in the first month of peritoneal dialysis predict technique survival.

BACKGROUND: Peritoneal transport of small solutes generally increases during the first month of peritoneal dialysis (PD). The aim of this study was to prospectively evaluate the ability of the peritoneal equilibration test (PET), carried out 1 and 4 weeks after the commencement of PD, to predict subsequent technique survival. METHODS: Fifty consecutive patients commencing PD at the Princess Alexandra Hospital between 1 February 2001 and 31 May 2003 participated in the study. Paired 1 week and 1 month PET data were collated and correlated with subsequent technique survival. RESULTS: A significant increase was observed in the dialysate : plasma creatinine ratio at 4 h (D/P Cr) between 1 and 4 weeks after the onset of PD (0.55 +/- 0.12 vs 0.66 +/- 0.11, P <0.001). Mean death-censored technique survival was superior in patients who experienced > or =20% rise in D/P Cr during the first month of PD compared with those who did not (2.3 +/- 0.2 vs 1.6 +/- 0.2 years, P <0.05). Using a multivariate Cox proportional hazards model analysis, the significant independent predictors of death-censored technique survival were an increase in D/P Cr of greater than 20% during the first month (adjusted hazard ratio [HR] 0.20, 95% CI 0.05-0.75), the absence of diabetes mellitus, the absence of ischaemic heart disease, body mass index and baseline peritoneal creatinine clearance. CONCLUSIONS: A 20% or greater rise in D/P Cr during the first month of commencing PD is independently predictive of PD technique survival. Further investigations of the mechanisms underlying this phenomenon are warranted.