Hydrodynamic Mechanism for Clumping along the Equatorial Rings of SN1987A and Other Stars.

An explanation for the origin and number of clumps along the equatorial ring of Supernova 1987A has eluded decades of research. Our linear analysis and hydrodynamic simulations of the expanding ring prior to the supernova reveal that it is subject to the Crow instability between vortex cores. The dominant wave number is remarkably consistent with the number of clumps, suggesting that the Crow instability stimulates clump formation. Although the present analysis focuses on linear fluid flow, future nonlinear analysis and the incorporation of additional stellar physics may further elucidate the remnant structure and the evolution of the progenitor and other stars.

A systematic review of the complications of contemporary total elbow arthroplasty.

BACKGROUND: Total elbow arthroplasty is a low volume procedure. We aimed to evaluate complication rates and cumulative percentages associated with the most frequently used contemporary implants and for the commonest indications. METHODS: A systematic literature search of all studies reporting complications following total elbow arthroplasty with 12-month minimum follow-up was undertaken. Quality of studies was assessed with the Methodological-Index-for-Non-Randomised-studies criteria. British NJR data identified the most common UK prostheses and indications. The complication rates for all undesirable events contributing to patient outcome were extracted and cumulative percentages were calculated. RESULTS: One hundred seventeen studies were screened, 12 studies included, totalling 815 procedures. Mean follow-up was 3.8 years. The overall complication cumulative percentage was 60.7%, significantly higher than that seen in other joint arthroplasty, including a 6.5% deep infection rate. Nerve injury was comparable between implants at around 4.1%. Radiographic loosening had a cumulative rate of 17.2%. Revision for symptomatic aseptic loosening was 6.3%. CONCLUSIONS: This is the largest systematic review of the complications of total elbow arthroplasty. Surgeons should be aware of differing complications related to their implant of choice, each having its own specific complication. Trauma as an indication appears to have an increased complication rates compared to inflammatory arthropathy. There is a lack of literature regarding the independent results of osteoarthritis as a specific indication for total elbow arthroplasty.

Arthroscopy of the symptomatic shoulder arthroplasty.

BACKGROUND: Assessment of a painful or stiff shoulder arthroplasty can be challenging. The cause of pain can sometimes be easily identified. However, some patients have normal levels of inflammatory markers, normal plain films, and no clinical signs to indicate a diagnosis. Indolent organisms may not raise blood marker levels or result in obvious radiologic findings such as loosening. We report the utility of performing arthroscopy in these patients for a diagnostic advantage. METHODS: We retrospectively reviewed the health records of all patients who underwent diagnostic shoulder arthroscopy over a 3-year period. Patients were included if they were aged 18 years or older, had undergone previous arthroplasty surgery, and had symptoms of shoulder pain or stiffness. Patients were excluded if they had any traditional symptoms of infection or had a raised serum white cell count or C-reactive protein level prior to diagnostic arthroscopy. RESULTS: Fourteen patients met the initial inclusion criteria. The mean interval between index surgery and arthroscopic evaluation was 65.4 months (standard deviation, 58 months; range, 17-192 months). Arthroscopic biopsy specimens returned positive culture results in 3 patients (21%). Rotator cuff tears were noted in 8 patients (57%). Capsular contraction requiring release was noted in 2 patients (10%). In all patients, the diagnostic arthroscopy directed the next stage of management. CONCLUSIONS: Diagnostic arthroscopy allows a full assessment of implants, the rotator cuff, the native articular surfaces, and scar tissue, as well as biopsy specimens to be obtained for indolent infection, in patients considering revision arthroplasty surgery. This allows a more informative consent process for patients, directs surgical management, and on occasion, allows for therapeutic intervention in a painful or stiff shoulder arthroplasty.

Roles of the International Council for Laboratory Animal Science (ICLAS) and International Association of Colleges of Laboratory Animal Medicine (IACLAM) in the Global Organization and Support of 3Rs Advances in Laboratory Animal Science.

Practical implementation of the 3Rs at national and regional levels around the world requires long-term commitment, backing, and coordinated efforts by international associations for laboratory animal medicine and science, including the International Association of Colleges of Laboratory Animal Medicine (IACLAM) and the International Council for Laboratory Animal Science (ICLAS). Together these organizations support the efforts of regional organization and communities of laboratory animal science professionals as well as the development of local associations and professional colleges that promote the training and continuing education of research facility personnel and veterinary specialists. The recent formation of a World Organization for Animal Health (OIE) Collaborating Center for Laboratory Animal Science and Welfare emphasizes the need for research into initiatives promoting laboratory animal welfare, particularly in emerging economies and regions with nascent associations of laboratory animal science.

Principles of rodent surgery for the new surgeon.

For both scientific and animal welfare reasons, training in basic surgical concepts and techniques should be undertaken before ever seeking to perform surgery on a rodent. Students, post-doctoral scholars, and others interested in performing surgery on rodents as part of a research protocol may not have had formal surgical training as part of their required coursework. Surgery itself is a technical skill, and one that will improve with practice. The principles of aseptic technique, however, often remain unexplained or untaught. For most new surgeons, this vital information is presented in piecemeal fashion or learned on the job, neither of which is ideal. It may also make learning how to perform a particular surgery difficult, as the new surgeon is learning both a surgical technique and the principles of asepsis at the same time. This article summarizes and makes recommendations for basic surgical skills and techniques necessary for successful rodent surgery. This article is designed to supplement hands-on training by the user's institution.

Reflections on improved health status of rodents bred for research: contributions to the reduction and refinement of animal use.

Reductions and refinements in the use of animals have steadily occurred over the last century. The need for improved health status has been a catalyst for much of this effort. This has also driven improvements in the housing and husbandry techniques required to maintain the health status of animals produced or used for biomedical research. This has decreased the number of animals used in biomedical research studies, contributed to refinements in animal care and use, and has resulted in better science as well as better animal welfare.

Large-scale rodent production methods make vendor barrier rooms unlikely to have persistent low-prevalence parvoviral infections.

A recent article in Contemporary Topics in Laboratory Animal Science by Pullium and colleagues expressed the opinion that because no other source could be found for a parvoviral contamination detected in sentinel mice prior to deployment, the infection apparently came from the unspecified vendor, even though no antibodies were ever detected in mice within 3 weeks of arrival. As this opinion may be shared by others and expresses some of the deep frustration in trying to detect the source of parvoviral infection in facilities using cage-level bioexclusion housing, Charles River Laboratories (CRL) feels it important to contribute to scientific dialogue by claiming to be the unnamed vendor in the Pullium article and discussing why a parvoviral contamination in a CRL barrier room would be detected rapidly. We show that viral infections in CRL barrier rooms rapidly reach high prevalence and that such contaminations historically have been detected quickly, and we describe why we feel enhancements in current monitoring methods provide for even more rapid detection of parvoviruses. Furthermore, we present substantial evidence that the barrier rooms that served as the source of the customer-suspect sentinel mice remain free of all parvoviruses, in light of monitoring of hundreds of mice by all available techniques. Therefore, although an initial list of all possible sources of contamination prudently should include vendors, the evidence is overwhelming that this vendor was not the source of the parvoviral contamination discussed in the Pullium paper.