An analysis was made of the various possible activators of single-chain urokinase-type plasminogen activator (scu-PA) in the dextran sulphate euglobulin fraction (DEF) of human plasma. scu-PA activators were detected in an assay system in which the substrate scu-PA, in physiological concentration (50 pM), was immuno-immobilized. After activation of the immobilized scu-PA for a certain period of time the activity of the generated amount of immuno-immobilized two-chain u-PA was determined with plasminogen and the chromogenic substrate S-2251. The scu-PA activator activity (scuPA-AA) in the DEF of plasmas deficient in factor XII or prekallikrein was about half of that in the DEF of normal plasma. Separation of scuPA-AA in the DEF by gel chromatography showed to major peaks, one eluting with an apparent Mr of 500,000 and the other around Mr 100,000. The former peak, which coincided with the activity peak of the kallikrein-kininogen complex, was absent in the DEF of plasma depleted of prekallikrein and therefore was identified as kallikrein. The latter peak was still present in the depleted plasma and most likely represents plasmin, because its scuPA-AA coincided with the activity peak of plasmin and could be fully inhibited by antibodies raised against human plasminogen. It is concluded that plasmin and the contact-activation factor kallikrein each contribute for about 50% to the scuPA-AA in the DEF. Compared on a molar basis, however, plasmin was found to be almost 1,000 times more effective than kallikrein, and we conclude, therefore, that in vivo plasmin is the primary activator of scu-PA and the role of the contact system is of secondary importance.
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Stimulating physical activity behaviour in persons with a physical disability is important, especially after discharge from rehabilitation. A tailored counselling programme covering both the period of the rehabilitation treatment and the first months at home seems on the average effective. However, a considerable variation in response is observed in the sense that some patients show a relevant beneficial response while others show no or only a small response on physical activity behaviour. The Rehabilitation, Sports and Active lifestyle (ReSpAct) study aims to estimate the associations of patient and programme characteristics with patients' physical activity behaviour after their participation in a tailored counselling programme. METHODS AND ANALYSIS: A questionnaire-based nationwide longitudinal prospective cohort study is conducted. Participants are recruited from 18 rehabilitation centres and hospitals in The Netherlands. 2000 participants with a physical disability or chronic disease will be followed during and after their participation in a tailored counselling programme. Programme outcomes on physical activity behaviour and patient as well as programme characteristics that may be associated with differences in physical activity behaviour after programme completion are being assessed. Data collection takes place at baseline and 14, 33 and 52 weeks after discharge from rehabilitation. ETHICS AND DISSEMINATION: The study protocol has been approved by the Medical Ethics Committee of the University Medical Centre Groningen and at individual participating institutions. All participants give written informed consent. The study results will provide new insights into factors that may help explain the differences in physical activity behaviour of patients with a physical disability after they have participated in the same physical activity and sports stimulation programme. Thereby, it will support healthcare professionals to tailor their guidance and care to individual patients in order to stimulate physical activity after discharge in a more efficient and effective way.
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The present study examined whether performance characteristics discriminated between selected and deselected players in talent development programmes. This examination was carried out in talented soccer players, aged 16-18 years using objective measurement instruments. Four domains of multidimensional performance characteristics (physiological, technical, tactical and psychological) were assessed by using a test battery consisting of soccer-specific field tests and questionnaires. Multivariate analyses of covariance revealed that the physiological characteristics peak and repeated shuttle sprint, the technical characteristics of peak and repeated shuttle dribble and the tactical characteristic of 'positioning and deciding', significantly differed between the selected (n=76) and deselected players (n=37), with selected players performing better (P<0.05). Discriminant function analysis showed that the combination of the technical characteristic 'peak dribbling', the tactical characteristic 'positioning and deciding' and the physiological characteristic of 'peak sprinting' classified 69% of talented players correctly. In conclusion, the decisions made by the investigated clubs to either select or deselect players in their talent development programme, whom were aged 16-18 years, were mostly discriminated by aspects of the players' technical, tactical and physiological skill performances. Sports research can play an essential role in investigating the club's perception of important performance characteristics in talented players.
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