Sheng li xue bao : [Acta physiologica Sinica]
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The aim of this study is to develop backpropagation neural networks (BPNN) for better prediction of ventilatory function in children and adolescents. Nine hundred and ninety-nine healthy children and adolescents (500 males and 499 females) aged 10-18 years, all of the Han Nationality, were selected from Inner Mongolia Autonomous Region, and their heights, weights, and ventilatory functions were measured respectively by means of physical examination and spirometric test. Using the approaches of BPNN and stepwise multiple regression, the prediction models and equations for forced vital capacity (FVC), forced expiratory volume in one second (FEV1), peak expiratory flow (PEF), forced expiratory flow at 25% of forced vital capacity (FEF25%), forced expiratory flow at 50% of forced vital capacity (FEF50%), maximal mid-expiratory flow (MMEF) and forced expiratory flow at 75% of forced vital capacity (FEF75%) were established. ⋯ The coefficients of variance (CV) for FEF50%, MMEF and FEF75% were higher than those of the other ventilatory function parameters, and their increasing percentages of R values (ΔR, relative to R values by LR's equation) derived by BPNN were correspondingly higher than those of the other indexes. In sum, BPNN approach for ventilatory function prediction outperforms the traditional regression methods. When CV of a certain ventilatory function parameter is higher, the superiority of BPNN would be more significant compared with traditional regression methods.
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The aim of the present study was to investigate the changes of lymphatic contraction after hemorrhagic shock in vitro and the underlying role of nitric oxide (NO). Rat thoracic duct segments were isolated at 0, 0.5, 1, 2 and 3 h after hemorrhagic shock. Using Pressure Myograph System, we determined contraction frequency (CF), end systolic diameter (ESD), end diastolic diameter (EDD) and passive diameter (PD) of isolated rat lymphatics under different transmural pressures (1, 3, 5, 7 and 9 cmH(2)O), then calculated contraction amplitude (CA), tonic index (TI) and fractional pump flow (FPF) of lymphatics. ⋯ Moreover, NOS inhibitor L-NAME elevated the CF, TI and FPF of 2 h shock lymphatics to the control levels, while phosphodiesterase inhibitor aminophylline (AP) suppressed the effect of L-NAME. These results suggest that the lymphatic contractile activity exhibits a biphasic change during hemorrhagic shock, increasing in early phase and declining in later stage. And NO plays a major regulating role in the biphasic change of lymphatic contraction in hemorrhagic shock rats via cGMP pathway.