Is pregnancy the best treatment for hyperprolactinaemia?

This paper reports the changes in prolactin levels after 12 spontaneous and 52 induced pregnancies in 54 women with unambiguous hyperprolactinaemia (median plasma prolactin levels 67.5 ng/ml, range 40-400). Twenty-three of the patients showed radiological evidence of prolactinoma. The pregnancies were induced in 37 patients by bromocriptine, in nine by metergoline, in two by lisuride and in four by other treatments. Of the 64 pregnancies, 16 ended in spontaneous abortion, while 48 went to term. Follow-up was continued for at least 6 months after delivery or until the end of lactation. In a control group of 32 hyperprolactinaemic women (median prolactin 70 ng/ml, range 40-400) not wishing to become pregnant, prolactin changes were similarly registered over a mean period of 15 months without any treatment (range 6-38 months). After pregnancy, a significant downward trend of plasma prolactin was observed in the puerperal women with a 'normalization' rate of 17%. No changes were observed in the 32 controls who did not become pregnant.     

Relation between electromyogram and torque of isometric reflex contractions in man

Human subjects maintained isometric plantar or dorsal flexions of the ankle in a matching task. H-reflexes of different sizes were superimposed on the steady activity. The peak-to-peak amplitude of the reflexes was measured on the electromyogram (EMG) of the soleus muscle. The size of the corresponding muscle contractions was determined on the isometric torque signal in relation to the maintained flexion force. The EMG-torque relation which was defined as the reflex muscle contraction as a function of the EMG reflex signal approximated a square root function for a given steady contraction level. It was not modulated by steady dorsal flexions, but it decreased continuously with stronger plantar steady torques. This dependence was caused by the silent period following the reflex discharge. Since the reflex discharge and the silent period were near in time to the duration of the contraction, the silent period had a direct effect on the reflex contraction amplitude.     

Value of continuous monitoring of the electrocardiogram in asymptomatic subjects

The authors analysed the prevalence of atrioventricular conduction defects and sinus node dysfunction by Holter monitoring in three population groups with similar clinical characteristics: 50 controls (Group I), 17 physically fit subjects with an atrioventricular conduction defect on the resting ECG which was usually asymptomatic (Group II), and 48 professional pilots who were also physically fit but who had no conduction defects on resting ECG (Group III). The 24 hour recordings showed: --a similar incidence of sinus dysrhythmias and atrioventricular conduction defects in the three groups although the frequency of low degree block was a little higher in sportsmen; --a preponderance of the association of first degree block and nocturnal Luciani-Wenckebach periods, sometimes with episodes of Mobitz II block; --the absence of progression to high-degree atrioventricular block. Holter monitoring would therefore seem to be a good method of detecting and following up abnormalities of sinus node function and atrioventricular conduction defects in asymptomatic patients. In addition, it gives a qualitative and quantitative assessment of the recorded changes and provides a means of monitoring their evolution.     

Effect of estrogen on calcium homeostasis and pituitary hormones in the growing chick

An experiment was carried out to investigate the effect of a range of estradiol (E2) doses (0.1-6.5 micrograms/g body wt/day) on vitamin D metabolism and the plasma levels of growth hormone (GH) and prolactin (PRL) in the growing chick. Doses of 0.5-0.7 microgram/g E2, which are insufficient to raise the plasma calcium level, did induce an increase in growth rate, an increase in 25-hydroxyvitamin D 1 alpha-hydroxylase (1-hydroxylase) and 24-hydroxylase activities, and an increase in plasma GH level. These parameters leveled off or fell over the dose range 1-2 micrograms/g E2 but there was evidence of a second peak in 1-hydroxylase activity at 6 micrograms/g E2. At this high dose rate, the plasma Ca level rose to 8 mM, as it does in the laying hen; 24-hydroxylase activity, growth rate, and plasma GH and plasma PRL levels all decreased. It was concluded that the dose response to estrogen in the growing chick is not linear and, in the case of 1-hydroxylase activity, may even be biphasic.     

Antibacterial activities of the leaf extracts of Eugenia uniflora Linn. (Synonym Stenocalyx michelli Linn.) Myrtaceae

The aqueous, organic, and volatile oil extracts of leaves of Eugenia uniflora Linn. Family Myrtaceae were investigated for antibacterial properties using agar dilution techniques. The aqueous extract was the most active against the organisms compared to the organic and volatile oil extracts. The extracts were found to inhibit Gram positive Staphylococcus aureus and Bacillus subtilis and Gram negative Escherichia coli and Shigella dysentcriae. Pseudomonas aeruginosa, Klebsiella pneumoniac, and Salmonella typhi were not inhibited.     

The complex nature of the mechanism of toxicity of antibiotic dithiacyclohexadiene polyines (thiarubrines) from the asteraceae

Thiarubrine A, a dithiacyclohexadiene polyine from the roots of Chaenactis douglasii, and a related dithiacyclohexadiene from Rudbeckia hirta exhibit strong light-independent antibacterial and antifungal activity. This activity is enhanced by exposure to visible light. Visible light also converts the compounds to the corresponding thiophenes. These are antibiotic only when irradiated with UV-A. Dithiacyclohexadienes are the first polyines to exhibit such complex mechanisms of toxicity towards microorganisms.