Antenatal biochemical screening to predict low birthweight infants

Summary. Urine and plasma oestriol, plasma progesterone, human placental lactogen, α-glycoprotein and serum cystyl aminopeptidase were measured at intervals during 608 pregnancies. The predictive accuracy of low values for identification of pregnancies with low birthweight outcomes was assessed for each test at various gestations. Data were analysed to obtain 10th–90th centile values for each test from 28 weeks to delivery.
Groups with values under different centile levels were compared: those under the lower centiles had higher proportions but smaller absolute numbers of low birthweight infants than those under higher centiles. No test was superior to the others at all centiles and gestations. Biochemical screening of pregnant populations to identify high-risk groups for intensive fetal monitoring has limited potential. If screening is used, the definition of high-risk groups is best achieved by practical rather than statistical criteria. If monitoring facilities are available and well accepted by patients then higher centile'cut-offs'to define fetal risk may be used than when they are not. Combining any pair of tests with values below the 10th centile did not reduce false positive and negative predictions any more than could be achieved by movement of centiles up or down for a single test.     

Translumbar catheter redirection using a tip-deflector technique

A new technique is described for reversing the direction of the catheter tip during translumbar aortography, without the need for partial withdrawal of the catheter from the aortic lumen. The method ensures optimal delivery of contrast medium at the desired level, while avoiding the risk of retroperitoneal bleeding or dislodgement during catheter manipulation.     

Diagnostic value of a psychological test in cases of suspected child abuse

The use of the Bene-Anthony Family Relations Test is described and illustrated by three examples of child abuse. This test should be considered in the investigation of definite or suspected cases of abuse and as part of the preparation of court evidence.     

Monophasic Versus Biphasic Cardiac Stimulation: Mechanism of Decreased Energy Requirements

The purpose of the present study was to examine the effects of monophasic and biphasic stimulation under conditions of full and incomplete repolarization in an in vivo dog model and in an in vitro rabbit ventricular single cell model. Strength-interval curves were constructed with monophasic cathodal stimulation and biphasic subthreshold anodal followed by cathodal stimulation in dogs prior to and late after left anterior descending coronary artery occlusion. At the monophasic absolute refractory period plus 10 msec, less cathodal current was required for biphasic compared to monophasic stimulation (P = 0.04). Moreover, the biphasic absolute ventricular refractory period (116 +/- 8 msec) was significantly shorter than the monophasic absolute ventricular refractory period (136 +/- 15 msec) (P less than 0.02). At coupling intervals greater than 30 msec after the monophasic absolute ventricular refractory period, there was no distinction between monophasic and biphasic stimuli. Similarly enhanced excitability was observed with biphasic stimuli in infarcted hearts. Voltage clamp measurements mimicking conditions of the in vivo studies demonstrated that when repolarization is incomplete, a hyperpolarizing prepulse reactivates additional sodium current resulting in enhanced excitability. In conclusion, biphasic stimulation consisting of a hyperpolarizing anodal prepulse followed by a cathodal pulse decreases the current required for excitation compared to cathodal monophasic stimulation in a critical zone near the ventricular absolute refractory period.