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Phenobarbitone can induce thyroid tumors through a non-genotoxic mechanism. However, this does not mean that this is the only mechanism through which phenobarbitone can mediate its effects. It has long been known that cancer is a multifactorial disease and a single chemical can induce tumors through diverse routes. Although the non-genotoxic mechanism mediated by phenobarbitone is an important route, it is recognized that it is not the single operating mechanism.

Objectives: To assess the effect of propofol on the change in airway pressure produced by diaphragmatic contraction. Design and Setting: Prospective, controlled study in patients anaesthetised with propofol in a university hospital. Patients and Methods: We stimulated the phrenic nerves before and immediately after induction of anaesthesia in 11 subjects, using a pair of 43-mm mean diameter double magnetic coils and measured the change in airway pressure at the mouth (TwPmo) produced by the resulting diaphragmatic contraction. Supramaximality of stimulation was confirmed with electromyogram and pressure measurements. We recorded the change in Resting End Expiratory Position (REEP) using a spirometer. We applied an approximate correction for the effect of lung volume on the amplitude of twitch pressure produced by diaphragmatic contraction. Intervention: Following the initial stimulations, the patients were anaesthetised with a propofol infusion. Once stable, repeat measurements were made. Measurements and Results: Following induction, REEP fell by mean 0.3 l standard deviation (SD) 0.2 l. TwPmo fell by mean 14.2% SD 14.0% ( P = 0.01), mean 22.3% SD 11.7% corrected ( P < 0.001). Twitch transdiaphragmatic pressure fell by 18.1% and 20.0% (25.8% and 27.7% corrected) in two further subjects studied with oesophageal and gastric balloon catheters. Conclusion: Propofol does reduce the effectiveness with which diaphragmatic contraction produces changes of pressure in the airway. [ABSTRACT FROM AUTHOR]

Examines the increase use of combined spinal-epidural analgesia technique during labor in Great Britain. Reduction of the intensity of the motor block; Efficacy of the technique; Discussion of the possible causes of complications.

Abstract: Objectives: This study aims to determine whether the environmental pollutant and thyroid mimic, tetrabromobisphenol A (TBBPA), interferes with thyroid hormone measurement by immunoassays. Design & methods: Hormone-relevant concentrations of TBBPA were added to thyroid hormone-stripped human serum and subjected to 6 different thyroid hormone immunoassays. Results: TBBPA was negative in all of the thyroid hormone immunoassays tested except at very high concentration (above that expected in serum of TBBPA-exposed workers) where it gave a marginally positive result in one immunoassay (in house T4 radioimmunoassay (RIA)). Conclusions: Serum TBBPA present as a result of workplace exposure or its use as a fabric flame retardant is very unlikely to give false positive results in thyroid hormone immunoassays. [Copyright &y& Elsevier]