Variation and Variability in Skeletal Ossification of the Gray Short-tailed Opossum, Monodelphis domestica.

By reconstructing and comparing the sequence of ontogenetic (embryonic development and post-natal growth) events across species, developmental biologists have gained unique insights into the key processes underlying the evolution of modern lineages and their extinct relatives. However, despite the importance of intraspecific variation to evolutionary transformation and lineage divergence, variation in the sequence of developmental events is seldom acknowledged. Thus, how much variation or variability should be expected during ontogeny remains poorly understood and it is an open question to what extent it impacts interspecific comparisons of developmental patterns. To address this crucial question, we studied the skeletal development of the important biomedical and developmental model organism, Monodelphis domestica. We investigated cranial, forelimb, and hindlimb elements using ontogenetic sequence analysis (OSA) to quantify and assess the full range of variation and variability in the sequence of ossification. Our study documented that previously unrecognized variation exists during M. domestica ontogeny-with over 5000 sequences for the full 92 event analysis. Further, OSA revealed unexpectedly high variability (i.e., the propensity to express variation) in the sequence of ossification for the skull and across the entire skeleton. Reconstructed modal sequences were generally in agreement with previously recognized patterns, including earlier ossification of the facial skeleton and a slight offset between forelimb and hindlimb development. However, the full range of variation shows that the majority of specimens in our analysis followed developmental trajectories distinct from those recovered by prior studies. This level of variation is quite remarkable and demonstrates the importance of assessing intraspecific ontogenetic variation. By quantifying sequence polymorphism and studying how developmental variation and variability differ among species, we can clarify more precisely how developmental patterns differ among species and gain insights into how ontogeny itself evolves.

Antibody landscape of C57BL/6 mice cured of B78 melanoma via immunotherapy.

Hoefges et al. utilized a whole-proteome peptide array approach to show that C57BL/6 mice develop a large repertoire of antibodies against linear peptide sequences of their melanoma after receiving a curative immunotherapy regimen consisting of radiation and an immunocytokine. Antibodies can play an important role in innate and adaptive immune responses against cancer, and in preventing infectious disease. Flow cytometry analysis of sera of immune mice that were previously cured of their melanoma through a combined immunotherapy regimen with long-term memory showed strong antibody-binding against melanoma tumor cell lines. Using a high-density whole-proteome peptide array, we assessed potential protein-targets for antibodies found in immune sera. Sera from 6 of these cured mice were analyzed with this high-density, whole-proteome peptide array to determine specific antibody-binding sites and their linear peptide sequence. We identified thousands of peptides that were targeted by 2 or more of these 6 mice and exhibited strong antibody binding only by immune, not naive sera. Confirmatory studies were done to validate these results using 2 separate ELISA-based systems. To the best of our knowledge, this is the first study of the "immunome" of protein-based epitopes that are recognized by immune sera from mice cured of cancer via immunotherapy.

Cardiopulmonary exercise test indices of respiratory buffering before and after aerobic exercise training in women with pulmonary hypertension: Differentiation by magnitudes of change in six-minute walk test performance.

While aerobic exercise training (AET) has generally been shown to improve 6-min walk test (6MWT) distance (6MWD) in patients with pulmonary hypertension (PH), a substantial number of patients appear to adapt differently, with minimal or even negative changes in 6MWT distance being reported. PURPOSE: To compare post-aerobic exercise training adaptations in cardiorespiratory functional capacity across three groups of patients with PH: those with high (HI), low (LI) and negative (NEG) post-training increases in 6MWD. METHODS: Participants were 25 females (age 54 ± 11 years; BMI 31 ± 7 kg/m2) who completed a vigorous, 10-week, thrice weekly, supervised treadmill walking exercise program. Cardiopulmonary exercise tests (CPET) and 6MWT were completed before and after training. Ten of the 25 participants were classified as HI (range = 47-143 m), 11 were classified as LI (range = 4-37 m) and 4 were classified as NEG (range = -17 to -53 m). RESULTS: Peak CPET duration, WR and time to anaerobic threshold (AT) were significantly higher (p < 0.05) after training in both the LI and HI groups but not in the NEG group. There was a significant improvement in VE/VCO2 (p = 0.042), PETCO2 (p = 0.011) and TV (p = 0.050) in the HI group after training, but not in the NEG or LI group. CONCLUSION: These findings suggest that sustained ventilatory inefficiency and restricted respiratory buffering may mediate exercise intolerance and impede the ability to adapt to exercise training in some patients with PH.

CRASH-2 (Clinical Randomisation of an Antifibrinolytic in Significant Haemorrhage) intracranial bleeding study: the effect of tranexamic acid in traumatic brain injury--a nested randomised, placebo-controlled trial.

BACKGROUND: Tranexamic acid (TXA) has been shown to reduce blood loss in surgical patients and the risk of death in patients with traumatic bleeding, with no apparent increase in vascular occlusive events. These findings raise the possibility that it might also be effective in traumatic brain injury (TBI). OBJECTIVE: The Clinical Randomisation of an Antifibrinolytic in Significant Haemorrhage Intracranial Bleeding Study (CRASH-2 IBS) was conducted to quantify the effect of an early short course of TXA on intracranial haemorrhage and new focal cerebral ischaemic lesions in patients with TBI. DESIGN: CRASH-2 IBS was a prospective randomised controlled trial nested within the CRASH-2 trial. Randomisation was balanced by centre, with an allocation sequence based on a block size of eight. We used a local pack system that selected the lowest numbered treatment pack from a box containing eight numbered packs. Apart from the pack number, the treatment packs were identical. The pack number was recorded on the entry form, which was sent to the international trial co-ordinating centre in London, UK. Once the treatment pack number was recorded, the patient was included in the trial whether or not the treatment pack was opened or the allocated treatment started. All site investigators and trial co-ordinating centre staff were masked to treatment allocation. SETTING: Ten hospitals: (India) Aditya Neuroscience Centre, Sanjivani Hospital, CARE Hospital, Christian Medical College, Medical Trust Hospital, Jeevan Jyoti Hospital and (Colombia) Hospital Universitario San Vicente de Paul, Hospital Pablo Tobón Uribe, Hospital Universitario San José de Popayán and Fundación Valle del Lili. PARTICIPANTS: The trial was conducted in a subset of 270 CRASH-2 trial participants. Patients eligible for inclusion in the CRASH-2 IBS fulfilled the inclusion criteria for the CRASH-2 trial, and also had TBI [Glasgow Coma Scale score of ≤ 14 and a brain computerised tomography (CT) scan compatible with TBI]. Pregnant women and patients for whom a second brain CT scan was not possible were excluded. INTERVENTIONS: Participants were randomly allocated to receive either a loading dose of 1 g of TXA infused over 10 minutes followed by an intravenous infusion of 1 g over 8 hours or matching placebo. MAIN OUTCOME MEASURE: The primary outcome was the increase in size of intracranial haemorrhage growth between a CT scan at hospital admission and a second scan 24-48 hours later. RESULTS: One hundred and thirty-three patients were allocated to TXA and 137 to placebo, of whom information on the primary (imaging) outcome was available for 123 (92%) and 126 (92%) respectively. The analysis suggested that TXA was likely to be associated with a reduction in haemorrhage growth [adjusted difference -3.8 ml, 95% credibility interval (CrI) -11.5 ml to 3.9 ml], fewer focal ischaemic lesions [adjusted odds ratio (OR) 0.54, 95% CrI 0.20 to 1.46] and fewer deaths (adjusted OR 0.49, 95% CrI 0.22 to 1.06). CONCLUSIONS: This was the first randomised controlled study to evaluate the effect of TXA in TBI patients and it found that neither moderate benefits nor moderate harmful effects can be excluded. However, although uncertainty remains, our analyses suggest that TXA administration might improve outcome in TBI patients and provide grounds for evaluating this hypothesis in future research. TRIAL REGISTRATION: Current Controlled Trials ISRCTN86750102. SOURCE OF FUNDING: This project was funded by the NIHR Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 16, No. 13. See the HTA programme website for further project information.

A grid overlay framework for analysis of medical images and its application to the measurement of stroke lesions.

OBJECTIVES: To create and evaluate an interactive software tool for measuring imaging data in situations where hand-drawn region-of-interest measurements are unfeasible, for example, when the structure of interest is patchy with ill-defined boundaries. METHODS: An interactive grid overlay software tool was implemented that enabled coding of voxels dependent on their imaging appearance with a series of user-defined classes. The Grid Analysis Tool (GAT) was designed to automatically extract quantitative imaging data, grouping the results by tissue class. Inter- and intra-observer reproducibility was evaluated by six observers of various backgrounds in a study of acute stroke patients. RESULTS: The software tool enabled a more detailed classification of the stroke lesion than would be possible with a region-of-interest approach. However, inter-observer coefficients of variation (CVs) were relatively high, reaching 70% in "possibly abnormal" tissue and around 15-20% in normal appearing tissues, while intra-observer CVs were no more than 13% in "possibly abnormal" tissue and generally less than 1% in normal-appearing tissues. CONCLUSIONS: The grid-overlay method overcomes some of the limitations of conventional Region Of Interest (ROI) approaches, providing a viable alternative for segmenting patchy lesions with ill-defined boundaries, but care is required to ensure acceptable reproducibility if the method is applied by multiple observers. KEY POINTS: Computer software developed to overcome limitations of conventional regions of interest measurements • This software is suitable for patchy lesions with ill-defined borders • Allows a more detailed assessment of imaging data.

Recommendations for improving the assessment of postgraduate dental education.

This paper makes recommendations for the improvement of assessment in postgraduate dental education. The recommendations are based on a twelve-month study conducted in 1998/99 which evaluated the strengths and weaknesses of the existing assessment systems. Evidence was taken from examination syllabi, assessments and records. Semi-structured interviews were conducted with representatives from national bodies and with trainers and trainees in the West Midlands. Strengths in parts of the system include: commitment and professional experience; commissioned work; opportunity to share experience; a monitoring framework; procedures for maintaining standards and examples of broadbased assessments. Weaknesses include: lack of assessment of quality; existence of some forms of unregulated assessment; lack of transparency and lack of clarity between training and assessment. Development is recommended in three broad areas: a competence-based model of assessment; distinguishing assessment from the analysis of educational needs and quality assurance. The introduction of a competence-based model is the most significant and is addressed in some detail. Specific proposals for consideration by national regulatory bodies and education providers include: strengthening the management of assessment; national leadership in the development of a competence model of assessment; widening the assessment base; clearer criteria for inspection; revisions to how vocational training, HO/SHO training and general professional training are assessed and training for trainers.

The benefits and costs of continuing professional development (CPD) for general dental practice: a discussion.

This paper sets out the benefits and costs of continuing professional development (CPD) for general dental practice. These considerations are important in evaluating CPD yet they are rarely formally assessed. This paper draws on literature specifically on dentistry but also from across the medical profession and the economics of education and training. First, the costs of CPD are itemised with some suggestions as to how costs may be reduced. Second, the benefits are identified and the (limited) evidence on the value of CPD is surveyed. Finally, reasons why some GDPs might not undertake sufficient or appropriate CPD are explored and the need for guidance for dental practitioners is identified.

Assessment in postgraduate dental education: an evaluation of strengths and weaknesses.

UNLABELLED: This paper describes a study designed to evaluate assessment in postgraduate dental education in England, identifying strengths and weaknesses and focusing specifically on its relevance, consistency and cost-effectiveness. METHODS: A four-phase qualitative method was used: a mapping of current career paths, assessment policy, and issues (phase 1); more detailed studies of the practice of assessment for a range of courses, and the systemic/management perspective of assessment (i.e. quality assurance) (phases 2 and 3), and analysis and reporting (phase 4). Data were analysed from documents, interviews, group consultations and observations. RESULTS AND DISCUSSION: Five key issues may be distilled from the findings: (i) lack of formal assessment of general professional training; (ii) trainer variation in assessment; (iii) the extent to which assessments are appropriate indicators of later success; (iv) the relationship between assessment and patient care, and (v) data to assess the costs of assessment. CONCLUSION: Current assessment procedures might be improved if consideration is given to: assessment which supports an integrated period of general professional training; training for trainers and inspection procedures to address variation; more authentic assessments, based directly on clinical work and grading cases and posts, and better data on allocation of resources, in particular clinicians' time given to assessment.

A role for clinical audit and peer review in the identification of continuing professional development needs for general dental practitioners: a discussion.

The purpose of this paper is to discuss how the role of peer review and clinical audit may be used in the identification of the continuing professional development (CPD) needs of general dental practitioners (GDPs). Clinical audit and peer review are intrinsically valuable in terms of the continued professional development of GDPs. Collaborative clinical audit, in particular, can provide a framework for short course input and there are particular benefits to this combination of activities which might usefully be more widely encouraged. If open to analysis in a way which retains individual anonymity, peer review and clinical audit resumes, these could be used to inform the provision of CPD and, linked to the knowledge of audit facilitators, short courses might more closely match the CPD needs of local dentists.

A framework for the evaluation of continuing education short courses in dentistry.

The objective of this paper is to propose an evaluation framework for short courses in continuing education for general dental practitioners (GDPs) (so called, Section 63 courses). Existing monitoring and evaluation procedures in the West Midlands deanery were examined and an improved evaluation framework was then devised, piloted and revised. A 5 phase method was used incorporating the examination of existing practice (Phases 1 and 2), development of a new framework (Phase 3), piloting (Phase 4) and revision of the evaluation framework in the light of the pilot. This approach will be implemented in the West Midlands and may be adapted for national use (Phase 5). It was found that existing monitoring and evaluation was inconsistent in prevalence and scope. Those involved in short courses were in favour of a more consistent and visible evaluation, including some assessment of impact-on-practice and cost-effectiveness. In conclusion, meaningful evaluation needs to include four key processes: data gathering; data analysis; dissemination and, action planning (reviewing provision in the light of the data analysis). Thus, this evaluation framework feeds into a quality development cycle designed to ensure high quality and relevant short course provision for general dental practitioners.

Dextran as a radioactive microsphere suspending agent: severe hypotensive effect in rat.

The effects of different commercially available radioactive microsphere suspending solutions were studied on the cardiovascular hemodynamics of male, Sprague-Dawley rats. Single left ventricular injections of carbonized radioactive microspheres (15 +/- 5 micron diam) totaling 850,000 spheres, suspended in 10% dextran (mol wt, 73,000) solution with Tween, caused reductions in arterial pressure (control, 101; postinjection, 74 mmHg; P less than 0.001), with no change in heart rate. Identical injections made with isotonic saline solution plus Tween had no effect on either heart rate or arterial pressure. Independent studies were conducted to examine the effects of 1-ml injections of four suspending solutions without microspheres on the cardiovascular hemodynamics of rats. Isotonic saline had no hemodynamic effect, and isotonic saline plus Tween decreased only heart rate. Ten percent dextran soluton with Tween decreased arterial pressure, heart rate, peak left ventricular systolic pressure, and left ventricular end-diastolic pressure. Similar changes occurred when dextran solution without Tween was administered. These data demonstrate that 10% dextran solution used as a microsphere suspending agent induces a severe hypotensive response in rats. Furthermore, injections of up to 850,000 microspheres in isotonic saline solution do not alter arterial pressure in the rat.