RESUMO
A new support for solid-phase combinatorial organic synthesis has been developed, which we term a regio-reactive resin (R(3)-resin). The resin is based on a unique hydroxyl-functionalized cross-linker readily synthesized in two steps starting from 4-hydroxybenzaldehyde. The cross-linker's ease of synthesis and high purity enables the preparation of gel-type resins with regio-reactive orthogonal loading sites. The resin's swelling properties were investigated, and its potential utility was demonstrated via orthogonal reactivity of the pendant and cross-linker sites.
Assuntos
Resinas Vegetais/síntese química , Absorção , Álcoois/química , Reagentes de Ligações Cruzadas/química , Poliestirenos/química , Resinas Vegetais/química , ÁguaRESUMO
Mesylates or tosylates of delta-hydroxy-L-norvaline esters spontaneously afford L-proline esters upon exposure to aqueous buffer in near quantitative yield. This novel reaction has led to the development of a simple route to optically active proline esters.
Assuntos
Compostos de Benzil/síntese química , Prolina/análogos & derivados , Alcanossulfonatos/química , Sulfonatos de Arila/química , Mesilatos/química , Prolina/síntese química , Valina/análogos & derivados , Valina/químicaRESUMO
A retrospective study was performed at the Queens Medical Centre, Nottingham, UK to evaluate the potential value of PR interval analysis of the FECG compared to conventional intrapartum assessment with fetal heart rate monitoring. Two-hundred sixty-five labours were selected for monitoring. Outcome was assessed by the number of fetal scalp blood samples (FBS) performed and the associated incidence of acidosis in the first stage of labour, the mode of delivery and whether or not this was expedited for fetal heart abnormality or an abnormal scalp pH. The condition of the fetus at delivery was assessed by arterial and venous blood acid-base status, Apgar score and the need for admission to the neonatal intensive care unit. Conventional electronic fetal heart rate monitoring (EFM) was used in all labours. The addition of PR interval assessment would potentially reduce the numbers of normal FBSs being carried out from 85.5% to 26.8% and the proportion of cases of missed acidosis at delivery from 8.5% to 4.5%. These results highlight the potential benefit of PR interval analysis in improving interpretation of the intrapartum cardiotocograph and need to be tested by prospective randomised controlled study.
Assuntos
Eletrocardiografia , Monitorização Fetal , Trabalho de Parto , Feminino , Sangue Fetal , Frequência Cardíaca Fetal , Humanos , Concentração de Íons de Hidrogênio , Masculino , Gravidez , Estudos RetrospectivosRESUMO
OBJECTIVE: To study the effect of sampling rate on the accuracy of fetal heart rate recording in labour. DESIGN: Prospective observational study. METHODS AND SUBJECTS: The fetal heart rate was obtained from 153 fetuses in labour. The heart rate data was sampled at a rate of 0.5 Hz (every 2 s) and the means and standard deviations of 5-min segments compared against the mean and standard deviation for all beats in the same time interval. RESULTS: There was a highly significant correlation between the means (r = 0.994, p < 0.001) and standard deviations (r = 0.957, p < 0.001) of FHR sampled on successive beats compared with 2 s sampling. CONCLUSION: Two second sampling of the fetal heart rate in labour will allow a highly complex analytical algorithm to process the signal in near real time for objective analysis.
Assuntos
Cardiotocografia/métodos , Monitorização Fetal/métodos , Frequência Cardíaca Fetal/fisiologia , Trabalho de Parto/fisiologia , Processamento de Sinais Assistido por Computador , Algoritmos , Cardiotocografia/normas , Feminino , Monitorização Fetal/normas , Feto/fisiologia , Humanos , Gravidez , Estudos Prospectivos , Análise de Regressão , Estudos de Amostragem , Fatores de TempoRESUMO
Electrocardiograms (ECG) was examined in 15 fetuses during fetal heart rate decelerations in labour. Sinus bradycardia was demonstrated in six cases and in two cases inversion of the P wave was seen. In seven cases there was complete dissociation of the P wave from the QRS complex, indicating complete atrioventricular heart block. Many decelerations are vagally mediated, but such cases associated with complete atrioventricular heart block may be due to the effect of hypoxia on the bundle of His.
Assuntos
Eletrocardiografia , Bloqueio Cardíaco/fisiopatologia , Frequência Cardíaca Fetal/fisiologia , Bradicardia/fisiopatologia , Feminino , Monitorização Fetal , Humanos , Gravidez , Estudos RetrospectivosRESUMO
Previous studies have shown that the relationship between P-R interval of the fetal electrocardiogram (FECG) and the fetal heart rate (FHR) varies according to the acid-base status of the fetus. In the normal fetus there is a negative correlation between these two parameters. However, as acidosis develops, the relationship becomes positive. In order to express this relationship in a quantitative form, an index known as the ratio index (RI) has been derived. This index provides a cumulative time based description of the relationship between the P-R interval and FHR for the whole labour. The aim of this study was to evaluate this derived index and compare it with fetal hypoxia. The FECG was recorded from 132 fetuses during labour using a fetal scalp electrode, and analysed using the Nottingham FECG system. Changes in the nature of this relationship between the P-R interval and heart rate were compared against biochemical markers of asphyxia, namely umbilical artery pH, lactate and umbilical venous norepinephrine and hypoxanthine. Significant correlations were demonstrated between the RI and umbilical arterial pH (r = -0.38, P < 0.01), lactate (r = 0.36, P < 0.01), log10norepinephrine (r = 0.37, P < 0.01), and hypoxanthine (r = 0.28, P < 0.01). The measurement of the ratio index during labour may be a useful method of determining fetal hypoxia during labour.
