Birth outcomes in women exposed to diagnostic radiology procedures during first trimester of pregnancy: a prospective cohort study

INTRODUCTION

Exposure of the embryo or fetus to ionizing radiations is a potential danger since it may induce clinically relevant fetal and/or neonatal damages. The aim of the present study was to examine fetal and neonatal outcomes after maternal exposure to radio-diagnostic procedures during first trimester of pregnancy, and to evaluate whether these effects might be related to the fetal absorbed dose of ionizing radiations.

METHODS

A 10-year prospective cohort study was performed on 1979 pregnant women who underwent a radio-diagnostic procedure within the first trimester of pregnancy. Women were divided into two groups: those exposed to abdominal or lumbar radio-diagnostic procedure (Cohort A, n = 130), and those exposed to radio-diagnostic procedures in any other body regions (Cohort B, n = 415). Health physicists performed tailored fetal radiation dose calculation. Multivariate logistic regression model was used to estimate the risk of adverse pregnancy outcomes.

RESULTS

The tailored fetal radiation dose was calculated for a total of 97 women (range 0.05-92 mSv). Major congenital malformations were detected in four infants in Cohort A, six infants in Cohort B, and 24 infants in controls (p = 0.445). Multivariate analysis confirmed the negative association between age and adverse pregnancy outcomes (OR 1.08 [1.06-1.11]), and the protective role of folic acid. A higher rate of small for gestational age seems to be present in women who underwent radio-diagnostic procedures that involve maternal thyroid.

CONCLUSION

Despite several limitations, our study confirms that exposure to radio-diagnostic procedures that may involve uterus at doses below 100 mSv does not increase the risk of embryo-fetal toxicity. The relationship between maternal thyroid irradiation and small for gestational age needs to be further investigated.

Nonlinear diffusion and thermo-electric coupling in a two-variable model of cardiac action potential

This work reports the results of the theoretical investigation of nonlinear dynamics and spiral wave breakup in a generalized two-variable model of cardiac action potential accounting for thermo-electric coupling and diffusion nonlinearities. As customary in excitable media, the common Q₁₀ and Moore factors are used to describe thermo-electric feedback in a 10° range. Motivated by the porous nature of the cardiac tissue, in this study we also propose a nonlinear Fickian flux formulated by Taylor expanding the voltage dependent diffusion coefficient up to quadratic terms. A fine tuning of the diffusive parameters is performed a priori to match the conduction velocity of the equivalent cable model. The resulting combined effects are then studied by numerically simulating different stimulation protocols on a one-dimensional cable. Model features are compared in terms of action potential morphology, restitution curves, frequency spectra, and spatio-temporal phase differences. Two-dimensional long-run simulations are finally performed to characterize spiral breakup during sustained fibrillation at different thermal states. Temperature and nonlinear diffusion effects are found to impact the repolarization phase of the action potential wave with non-monotone patterns and to increase the propensity of arrhythmogenesis.

Effect of taurine supplementation on fat and energy absorption in cystic fibrosis

In 10 children with cystic fibrosis and persisting steatorrhoea, supplementation with taurine (30-40 mg/kg/day) was given for two months as an adjunct to the usual pancreatic enzyme treatment. A three day fat and energy balance was performed in patients with cystic fibrosis, before and after the supplementation, and in seven healthy controls who did not receive taurine. Faecal fat was measured by a gravimetric method and stool energy was determined using a bomb calorimeter. Patients with cystic fibrosis, before and after taurine, and healthy controls received the same fat and energy intake (calculated by a dietitian). In patients with cystic fibrosis taurine did not produce any improvement of steatorrhoea (mean (SD) faecal fat 8.7 (3.3) v 11.2 (7.0) g/day, respectively before and after the supplementation), of faecal energy loss (0.978 (0.468) v 1.133 (0.539) MJ/day), of faecal fat expressed as percent of fat intake (13.4 (5.6) v 15.1 (9.8)%), and of faecal energy expressed as percent of energy intake (9.9 (3.6) v 11.2 (5.7)%). Healthy controls had significant lower fat (3.5 (2.3) g/day) and energy 0.576 (0.355) MJ/day faecal losses. In conclusion, taurine failed to decrease significantly fat and energy losses. Our study does not support the use of taurine supplementation in the nutritional management of cystic fibrosis.