ObjectiveTo quantify the platelet concentration in the blood of SHR rats, by means of different centrifugation protocols, and to evaluate what the most effective method for obtaining platelets is.MethodsWe used 40 male rats of the isogenic SHR lineage. The animals were divided into three groups: control, using whole blood without centrifugation; single centrifugation, using whole blood subjected to a single centrifugation at 200 × g and 400 × g; and double centrifugation, using whole blood subjected one centrifugation at different rotations, followed by collection of whole plasma subjected to another centrifugation at different rotations: 200 × g + 200 × g; 200 × g + 400 × g; 200 × g + 800 × g; 400 × g + 400 × g; 400 × g + 800 × g. Samples of 3 ml of blood were drawn from each animal by means of cardiac puncture. The blood was stored in Vacutainer collection tubes containing 3.2% sodium citrate. The blood from the control group animals was analyzed without being subjected to centrifugation. After the blood from the other groups of animals had been subjected to centrifugation, the whole plasma was collected and subjected to platelet counting in the lower third of the sample.ResultsWe obtained greatest platelet enrichment in the subgroup with two centrifugations comprising 400 × g for 10 min + 400 × g for 10 min, in which the mean platelet concentration was 11.30 times higher than that of the control group.ConclusionIt was possible to obtain a high platelet concentration using viable simple techniques, by means of centrifugation of whole blood and use of commonly used materials. The most effective method for obtaining platelet concentrate was found in samples subjected to two centrifugations.
Background
Magnetic resonance imaging (MRI) is the gold standard in diagnosing rotator cuff pathology; however, there is a lack of studies investigating the reliability agreement for supraspinatus partial-thickness tears among orthopaedic surgeons and musculoskeletal (MSK) radiologists.
Methods
Sixty digital MRI scans (1.5 Tesla) were reviewed by two orthopaedic shoulder surgeons, two MSK radiologists, two fellowship-trained shoulder surgeons, and two fellowship-trained orthopaedic surgeons at two distinct times. Thirty-two scans of partial-thickness tears and twenty-eight scans of the supraspinatus tendon with no tears were included. Supraspinatus tendonosis and tears, long head of the biceps pathology, acromial morphology, acromioclavicular joint pathology and muscle fatty infiltration were assessed and interpreted according to the Goutallier system. After a four-week interval, the evaluators were asked to review the same scans in a different random order. The statistical analyses for the intra- and interobserver agreement results were calculated using the kappa value and 95% confidence intervals.
Results
The intraobserver agreement for supraspinatus tears was moderate among the MSK radiologists (k = 0.589; 95% CI, 0.446–0.732) and the orthopaedic shoulder surgeons (k = 0.509; 95% CI, 0.324–0.694) and was fair among the fellowship-trained shoulder surgeons (k = 0.27; 95% CI, 0.048–0.492) and the fellowship-trained orthopaedic surgeons (k = 0.372; 95% CI, 0.152–0.592). The overall intraobserver agreement was good (k = 0.627; 95% CI, 0.576–0.678). The intraobserver agreement was moderate for biceps tendonosis (k = 0.491), acromial morphology (k = 0.526), acromioclavicular joint arthrosis (k = 0.491) and muscle fatty infiltration (k = 0.505). The interobserver agreement results for supraspinatus tears were fair and poor among the evaluators: the MSK radiologists and the orthopaedic shoulder surgeons had the highest agreement (k = 0.245; 95% CI, 0.055–0.435).
Conclusions
In this sample of digital MRI scans, there was an overall good intraobserver agreement for supraspinatus partial tears; however, there were also poor and fair interobserver agreement results. The evaluators with higher levels of experience (the orthopaedic shoulder surgeons and the MSK radiologists) demonstrated better results than evaluators with lower levels of experience.
Electronic supplementary material
The online version of this article (10.1186/s12891-019-2760-4) contains supplementary material, which is available to authorized users.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.