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Biomedical subjects

John McMullen

Publications and source records attributed to John McMullen.

4 recordsLinked to original sources

Spurious leptomeningeal enhancement on immediate post-operative MRI for paediatric brain tumours.

Immediate post-operative MRI has been recommended as an accurate and robust method to assess residual brain tumour. Early enhancement at the resection margin and in the dura is well recognized, but we describe two cases of enhancement in the basal cisterns on immediate post-operative MRI that resolved on follow-up. The underlying cause of the enhancement remains to be elucidated, but it should be recognized that leptomeningeal enhancement may occur after surgery and that this does not necessarily imply tumour spread.

Biopsy↗

The effect of captivity and diet on KLH isoform ratios in Megathura crenulata.

Aquaculture of the giant keyhole limpet, Megathura crenulata, may provide a reliable long-term supply of keyhole limpet hemocyanin (KLH) for many promising biomedical applications. However, previous studies have reported a complete loss of the KLH1 isoform under certain cultivation conditions. We examined whether captivity per se and diet caused a significant change in the isoform profile of M. crenulata. Although there was a trend toward a decreasing percentage of KLH1 in some animals, in general isoform profiles were not significantly affected by captivity or dietary limitations. Further, the percentage of KLH1 significantly increased for limpets with previously low levels of KLH1 when fed a supplemental mixed diet. Our results indicate that normal isoform profiles can be maintained in limpets held in captivity even when fed insufficient diets, and that these conditions do not cause a complete loss of either KLH isoform. Notably, the enhancement of abnormally low levels of KLH1 suggests that variability in isoform profiles could potentially be minimized through diet. While there is a need for further research on the factors responsible for the variability of KLH, overall, these results support the premise that culture of M. crenulata may provide a sustainable source of this biomedically important product.

Animals↗

Qualitative clinical evaluation of scapular dysfunction: a reliability study.

The purpose of this study was to determine the intrarater and interrater reliability of a clinical evaluation system for scapular dysfunction. No commonly accepted terminology presently exists for describing the abnormal dynamic scapular movement patterns that are commonly associated with shoulder injury. A method of observation was devised for clinical evaluation of scapular dysfunction. Blinded evaluators (2 physicians and 2 physical therapists) were familiarized with the evaluation method of scapular movement patterns before viewing a videotape of 26 subjects with and without scapular dysfunction. Each evaluator was asked to categorize the predominant scapular movement pattern observed during bilateral humeral scaption and abduction motions. Reliability was assessed by a kappa coefficient. Intertester reliability (kappa = 0.4) was found to be slightly lower than intratester reliability (kappa = 0.5). These results indicate that, with refinement, this qualitative evaluation method may allow clinicians to standardize the categorization of dynamic scapular dysfunction patterns.

Adult↗

Scapular dyskinesis and its relation to shoulder pain.

Scapular dyskinesis is an alteration in the normal position or motion of the scapula during coupled scapulohumeral movements. It occurs in a large number of injuries involving the shoulder joint and often is caused by injuries that result in the inhibition or disorganization of activation patterns in scapular stabilizing muscles. It may increase the functional deficit associated with shoulder injury by altering the normal scapular role during coupled scapulohumeral motions. Scapular dyskinesis appears to be a nonspecific response to shoulder dysfunction because no specific pattern of dyskinesis is associated with a specific shoulder diagnosis. It should be suspected in patients with shoulder injury and can be identified and classified by specific physical examination. Treatment of scapular dyskinesis is directed at managing underlying causes and restoring normal scapular muscle activation patterns by kinetic chain-based rehabilitation protocols.

Athletic Injuries↗