Biomechanical correlates of running performance in active children.

OBJECTIVES: Examine the running kinematics in healthy, physically active prepubescent children and to determine if specific biomechanical factors correlate with running performance. DESIGN: Cross-sectional study. METHODS: Fifteen children (age 9years, ±11months) completed a 1km time trial before undergoing three-dimensional running motion analysis. RESULTS: A strong positive correlation was observed between the biomechanical variables of stride length (p<.01), contact time (p<.01) and ankle dorsiflexion angle (p=.04) with time trial performance. Between variable analyses revealed a strong positive correlation between peak angles of hip adduction and knee flexion. There was no correlation between hip adduction and knee flexion peak angles or the vertical displacement of centre of mass with trial performance. CONCLUSIONS: The results of this study show that children with a better time trial performance display longer stride length, shorter contact time and mid or forefoot strike pattern. These findings have implications for targeted technique intervention in children's running training to improve running performance.

Nitrite and nitroglycerin induce rapid release of the vasodilator ATP from erythrocytes: Relevance to the chemical physiology of local vasodilation.

Extracellular ATP released from circulating erythrocytes induces vasodilation by stimulating receptor-mediated endothelium NO/EDRF (endothelium-derived relaxing factor) production. We report that pre-stimulation of freshly isolated human erythrocytes with physiological nitrite (100 nM NO(2)(-)) or pharmacological nitroglycerin (10microM) concentrations resulted in >200% spike in ATP release, which was detected on resuspending the cells in fresh medium. The observed response was instantaneous following NO(2)(-) pre-stimulation but a delay of approximately 20 s followed nitroglycerin pre-stimulation, reflecting the time required for prodrug activation within the erythrocyte to its vasoactive metabolites, NO(2)(-) and NO. The data provided here are consistent with ATP being a conveyor of a NO-induced vasodilatory signal from the erythrocyte to the endothelium. Extended erythrocyte pre-stimulation with the NO donors resulted in a dose-dependent decrease in extracellular ATP, which would attenuate the signal in intact vessels to prevent excessive vasodilation. Importantly, our study constitutes the first report of enhanced vasodilator (ATP) release following human erythrocyte pre-stimulation by an endogenous (NO(2)(-)) or pharmacological (nitroglycerin) NO donor. The relevance of our findings to the therapeutic effects of nitroglycerin as well as to nitrate tolerance is discussed.

Thymoma: a review of the clinical and pathological findings in 65 cases.

INTRODUCTION: Although rare, thymoma is the most common tumour of the anterior mediastinum. In an effort to assess the clinical and pathologic characteristics of this tumour and to determine whether clinicopathologic stage or histopathologic classification correlates with clinical outcome, in the Department of Pathology and the Department of Surgery at the University of Saskatchewan we reviewed all cases of thymoma registered in the province of Saskatchewan using the database of the Saskatchewan Cancer Centre. METHODS: In 65 patients with a diagnosis of thymoma or thymic carcinoma identified from the Saskatchewan Cancer Centre database between Jan. 1, 1960, and Dec. 31, 2000, we studied the presentation, diagnostic investigations, therapeutic interventions, tumour size, postoperative course, clinical stage, histopathologic classification, disease recurrence and mortality. RESULTS: Of the 65 patients, 17 (26%) were asymptomatic and 11 (17%) had symptoms consistent with myasthenia gravis. Surgical resection is most commonly performed through a median sternotomy and frequently requires en bloc resection of one or more adjacent structures. The overall survival of patients with thymomawas found to correlate with the clinical stage as described by Masaoka and colleagues and with complete tumour resection. A trend to clinicopathologic correlation was observed when applying the histologic classification systems of Suster and Moran and the World Health Organisation, but this trend was not statistically significant. CONCLUSIONS: Thymoma is a rare tumour with a variable clinical presentation. Clinical outcome correlates with clinical stage and the ability to achieve complete tumour resection.

Nontraumatic massive hemoperitoneum from melanoma metastatic to the uterus.

We have reported a case of nontraumatic massive hemoperitoneum caused by melanoma metastatic to the uterus that was readily managed with surgery. We believe this strategy provided effective palliation, improved quality of life and potentially prolonged survival for this patient.

Heart-lung or lung transplantation for Eisenmenger syndrome.

BACKGROUND: The optimal therapy for end-stage Eisenmenger syndrome (ES) is unknown. We analyzed the United Network for Organ Sharing/International Society for Heart and Lung Transplantation Joint Thoracic Registry to determine predictors of survival. METHODS: Univariate analysis was performed using Kaplan-Meier survival curves. Groups were compared using the log-rank test. Multivariate analysis was performed using a proportional hazards model. RESULTS: There were 605 transplants performed between 1988 and 1998. The causes of ES included atrial septal defect (ASD) in 171, ventricular septal defect (VSD) in 164, multiple congenital anomalies (MCA) in 68 and patent ductus arteriosus (PDA) in 32. Procedures included 430 heart-lung (HLT), 106 bilateral lung, and 69 single lung transplants (LT). Survival after HLT was better than after LT on univariate analysis (p = 0.002). For HLT, survival at 30 days and 1 year was 80.7% and 70.1% compared with 68% and 55.2% for LT. Diagnosis was also a significant predictor of survival (p = 0.011), being best for VSD and MCA (1-year survival 71.4% and 77.6%). There was a highly significant benefit of HLT over LT for VSD patients (p = 0.0001). Diagnosis, the combination of diagnosis and procedure, recipient age, recipient gender, donor age, ischemic time and recipient status were significant in a multivariate model. Multivariate analysis confirmed the superior prognosis of patients with VSD or MCA (p = 0.007 and p = 0.022, respectively) and suggested that the adverse effect of LT was predominately in patients with VSD (risk ratio 1.817, p = 0.035). CONCLUSIONS: This analysis suggests that ES recipients are not a homogeneous group. Patients with VSD and MCA have the best prognosis. HLT appears to offer a survival benefit for patients with ES secondary to VSD and should be re-considered as the operation of choice.