ABSTRACT
INTRODUCTION: Fetal heart rate and its variability during the course of gestation have been extensively researched. The overall reduction in heart rate and increase in fetal HRV is associated with fetal growth and the increase in neural integration. The increased complexity of the demands on the cardiovascular system leads to more variation in the temporal course of the heart rate which has been shown to be reflected in measures of complexity. The aim of this work was to investigate novel complexity measures with respect to their ability to quantify changes over gestational age in individual fetuses consistently and in a stable manner. METHODS: We examined 215 fetal magnetocardiograms (FMCG), each of 5 min duration, in 11 fetuses during the second and third trimesters (at least 10 data sets per fetus). From the FMCG we determined the fetal RR beat durations. For each 5 min time-series of RR intervals we then calculated Shannon entropy, high spectral entropy, high spectral Detrended Fluctuation Analysis, spectral Multi-Taper Method as well as the standard deviation and two commonly used complexity measures: Approximate Entropy and Sample Entropy. For each subject and HRV measure, we performed regression analysis with respect to gestational age. The coefficient of determination R² was used to estimate 'goodness-of-fit', the slope of the regression indicated the strength of the individual dependency on gestational age. RESULTS: We found that the new complexity measures do not outperform ApEn. CONCLUSION: This study has now rejected the hypothesis that the spectral complexity measures outperform those applied previously.
INTRODUÇÃO: A freqüência cardíaca fetal e da sua variabilidade durante o curso da gestação têm sido extensivamente pesquisada. A redução global da frequência cardíaca e aumento da VFC fetal está associada com o crescimento fetal e aumento da integração neural. O aumento da complexidade das exigências sobre o sistema cardiovascular conduz a uma maior variação no decurso temporal da frequência cardíaca o que foi mostrado para reflectir-se medidas de complexidade. O objetivo deste trabalho foi investigar medidas de complexidade novos em relação à sua capacidade de quantificar as mudanças ao longo da idade gestacional em fetos individuais de forma consistente e de forma estável. MÉTODO: Foram examinados 215 magnetocardiograms fetais (FMCG), cada um dos 5 min de duração, em 11 fetos durante o segundo e terceiro trimestres (pelo menos 10 conjuntos de dados por feto). A partir do grande consumo determinamos as durações RR batimento fetais. Para cada série temporal 5 min dos intervalos RR então calculada Shannon entropia, alta entropia espectral, alta espectral Destendenciada Análise Flutuação, espectral Multi-Taper Método, bem como o desvio padrão e duas medidas de complexidade comumente utilizados: aproximado Entropia e Amostra Entropia. Para cada medida assunto e HRV, foi realizada análise de regressão em relação à idade gestacional. O coeficiente de determinação R² foi usada para estimar a "o bem-of-fit", a inclinação da regressão indicou a força do indivíduo dependência da idade gestacional. RESULTADOS: Verificou-se que as novas medidas de complexidade não superar ApEn. CONCLUSÃO: Este estudo agora rejeitou a hipótese de que as medidas de complexidade espectrais superar os aplicados anteriormente.
Subject(s)
Humans , Male , Female , Cardiovascular System , Entropy , Fetal Development , Fetus , Gestational Age , Heart Rate, Fetal , PregnancyABSTRACT
OBJECTIVE: The effects of natural adjuvants on lung inflammation and tracheal responsiveness were examined in sensitized guinea pigs. METHODS: The responses of guinea pig tracheal chains and the serum levels of interleukin-4 and interferon-gamma were examined in control pigs and three other groups of guinea pigs: the sensitized group and two other sensitized groups treated with either adjuvant G2 or adjuvant G2F (n = 7 for each group). Sensitization of the animals was achieved by injection and inhalation of ovalbumin. RESULTS: The results showed that sensitized animals had increased tracheal responsiveness and increased serum levels of interleukin-4 and interferon-gamma compared to controls (p<0.05 to p<0.001). Treatments with either G2 or G2F prevented the increase in tracheal responsiveness and serum interleukin-4 (p<0.01 to p<0.001). However, the serum levels of interferon-gamma and the interleukin-4-to-interferon-gamma ratio was increased in the treated groups (p<0.001 for all cases). CONCLUSIONS: These results indicate important preventive effects of two natural adjuvants, particularly G2, on the changes in tracheal responsiveness, serum cytokines and the interleukin-4-to-interferon-gamma ratio (T helper 1/T helper 2 balance) in sensitized guinea pigs. .