RESUMO
For researchers seeking to collect spinal cord samples from mice and rats while avoiding acid decalcification, few options are available. Laminectomy is the standard method which yields high quality samples, yet is time consuming and technically difficult. Ejection of the cord from the vertebral column is another technique commonly used; however, the literature suggests that this method can damage the spinal tissues and is typically avoided when histology of samples is the desired endpoint. Here, we describe an optimized method for ejection of spinal cords from rats and mice, and compare histological quality of these samples with those collected via laminectomy. Our results show that ejection can yield high quality spinal cord samples and may be suitable for use as an alternative to laminectomy.
RESUMO
BACKGROUND: In the implantable cardiac device (CD) population, not only can clinically silent atrial tachyarrythmias (AT) be detected, but an associated AT burden can be documented. There are two methods of determining stroke risk: CHADS2 and CHA2DS2-VASc. Recommendations for initiating anticoagulation based on stroke risk profiles and/or AT burden remain unclear for device-detected AT. OBJECTIVE: Aims of this study were to reveal the AT burden among CD patients, determine CHADS2 and CHA2DS2-VASc scores among patients with an AT burden, and evaluate current practices for anticoagulation. METHODS: Records were reviewed from patients undergoing a new CD implant within the last three years from two device clinics. Continuous variables were expressed as mean with standard deviation (SD) and categorical variables were stated as numbers and percentages. The categorical variables were compared using the Chi2 Square test and the continuous variables were compared using the independent 2-sided t-test. RESULTS: There were 275 CD patients enrolled. Eighty-seven had an AT burden and 188 patients did not have an AT burden. CD patients with AT burden were older than those without AT burden [69 (11), p=0.007]. Patients with AT burden had more hypertension and previous history of stroke (p=0.038, p=0.005) compared to those without AT burden. Both the CHADS2 and CHA2DS2-VASc mean scores were higher in patients with an AT burden (p=0.018 and p=0.041). Thirty patients with a previous history of AT were on anticoagulation (p=<0.001) prior to implant. Forty-eight patients had a new diagnosis of AT (NDAT) and 46% (n=22) were started on anticoagulation. CONCLUSIONS: An AT burden was detected in 32% of patients with at least 75% falling within a high-risk category using both scores. However, less than half of NDAT patients were started on anticoagulation. The use of oral anticoagulation in practice remains inconsistent and further randomized trials are recommended.
RESUMO
To collect complete rodent spinal cord samples for histological analysis, researchers typically use a method that involves fixation of the carcass, followed by decapitation and removal of the vertebrae and the spinal cord. Researchers then decalcify, process and embed the spinal column in paraffin. When this method is used, the spinal cord retains its natural curvature, which may be undesirable to some investigators. The authors describe a methodology by which the entire spinal cord, with the brain attached, can be removed from a mouse or rat, set against a rigid support material and fixed perfectly straight. This allows for more precise sectioning and simplified histological analysis. Researchers can even create block preparations, each of which contains multiple spinal cord sections, so that they can compare anatomically matched sections. This procedure can also be used to obtain fresh spinal cord samples that are free of bone and can be frozen in optimal cutting temperature medium.