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1. The potential use of an extrinsic label to measure iron absorption from a ferric orthophosphate-fortified malted cocoa drink was examined by measuring the solubility of the FePO4 in 0·1 M-hydrochloric acid.2. The validity of using the stable isotope 58Fe as an extrinsic label was tested by comparing Fe absorption by rats from wheat flour extrinsically-labelled with 58Fe or 59Fe.3. Fe absorption from a malted cocoa drink (20 g powder made up with hot water) fortified with FePO4 (0·5 mg Fe/g powder) was measured in human subjects using 58Fe as an extrinsic label. Absorption was calculated by measuring unabsorbed 58Fe in faeces. Absorptions of Fe from the drink fortified with either FePO4 or ferrous sulphate were compared. The effect of the addition of ascorbic acid to the drink (1 mg/g powder) on Fe availability was also examined.4. The effect of fasting on Fe absorption from the drink was determined in rats by giving the drink to fasting animals or shortly after they had consumed a small meal.5. The FePO4 was totally soluble in 0·1 M-HCl and there were no differences in absorption between 58Fe- and 59Fe-labelled wheat flour. In the human experiment the proportion of Fe absorbed from the drink plus FePO4 and ascorbic acid was (mean with SE) 0·25 (0·02), from the drink plus FePO4 0·24 (0·02) and from the drink plus FeSO4 0·23 (0·03). Fasting had a significant effect on Fe availability; rats given the drink shortly after a small meal absorbed less than half as much Fe as those given the drink on a fasted stomach.6. It was concluded that the FePO4 used to fortify the malted cocoa drink was as well absorbed as FeSO4 but that the high levels of absorption were a reflection of the fasting condition of the subjects. The level of ascorbic acid was not great enough to enhance the availability of the FePO4 any further.

1 The cardiovascular effects of histamine were examined in dogs anaesthetized with pentobarbitone 2 The effect of histamine on heart rate, blood pressure, left ventricular pressure, dP/dt,,,nv, and dP/dt: IIT (integrated isometric tension) was compared in the presence and absence ofautonomic reflexes and blood pressure control. 3 In innervated animals with no attempt to control blood pressure, histamine produced dosedependent decreases in blood pressure and heart rate and either positive or negative inotropic actions. 4 When autonomic reflexes were abolished, this variability in inotropic response was reduced and histamine produced a slight positive inotropic response. There was a decrease in blood pressure and a positive chronotropic response to histamine. 5 When blood pressure was controlled and the cardiac nerves were intact, histamine produced a decrease in heart rate. However, in the denervated animals, there was a slight increase in heart rate. 6 Inotropic responses to histamine in the blood pressure controlled groups were less variable than when blood pressure was uncontrolled. In all of these animals there was an increase in contractility, the increase being more marked in the denervated group. 7 The H2-receptor agonist impromidine produced a positive inotropic action in intact animals with uncontrolled blood pressure.

Female rats were fed from weaning on diets with sucrose, starch, glucose or fructose as the carbohydrate source. Animals were killed at various stages throughout pregnancy and early lactation. Maternal plasma triglycerides (TG), cholesterol, free fatty acids, glucose, insulin and corticosteroids were measured. Lipogenic activity was assayed in the livers, adipose tissue and mammary tissue, and the results compared with those from non-pregnant rats. Insulin, corticosteroids and hepatic lipogenesis were also assayed in the embryos and in newborn pups. Dietary sucrose and fructose produced a significantly higher concentration of plasma TG in the non-pregnant, pregnant and lactating rats than did starch and glucose. All the diets led to an increase in TG concentration at the 20th day of pregnancy, which returned to the original concentration 2 days post-partum. The hypertriglyceridaemia of late pregnancy was accentuated by the feeding of sucrose and fructose. Maternal concentrations of plasma glucose were significantly reduced towards the end of pregnancy in all dietary groups. The replacement of starch by sucrose, or of glucose by fructose, enhanced hepatic lipogenesis. Fructose but not sucrose depressed fat synthesis in the adipose tissue. Hepatic fatty acid synthetase activity was increased in late pregnancy on all diets except that with starch. Late pregnancy intensified hepatic lipogenesis in rats fed sucrose or fructose. The results are discussed in relation to the metabolic changes during pregnancy and to sucrose feeding.

1 This study was designed to assess the effects of exogenous neuropeptide Y (NPY) on cardiac contractility and coronary blood flow (CBF) in anaesthetized dogs and to evaluate the effect of NPY on the responses to sympathetic and parasympathetic stimulation and to inotropic agents.2 Bolus doses of NPY (500.ug), administered via the femoral vein, increased mean arterial pressure. The pressor effect was associated with reductions in heart rate, CBF and cardiac contractility. 3 The effects of NPY (500pug) on contractility and CBF were compared with that of vasopressin (VP) (1 unit). For similar reductions in CBF, NPY and VP had similar negative inotropic effects. Thus, it is likely that the negative inotropic response to NPY is not due to a direct effect of NPY on the heart muscle but is largely due to coronary vasoconstriction. 4 In the presence of NPY (500,pg, i.v.), there was an inhibition of the positive inotropic response to stimulation of the left cardiac sympathetic nerve (2 or 5Hz, 0.05 ms). NPY also inhibited the negative inotropic response and chronotropic response to vagal stimulation (2, 3 or 5 Hz, 0.05 ms). 5 Dose-response curves were obtained for the inotropic, chronotropic and pressor responses to cumulative infusions of noradrenaline (n = 6) and dobutamine (n = 6). NPY had no effect on these dose-response curves.6 The effect of NPY on the responses to salbutamol and impromidine was assessed. NPY did not alter the positive inotropic, chronotropic or depressor responses to these agonists. 7 Our results indicate that NPY has direct, postsynaptic vasoconstrictor activity and the reduction in myocardial contractility and heart rate are due to a combination of coronary vasoconstriction, baroreceptor reflex activation and presynaptic inhibition of transmitter release from sympathetic nerves. The welldocumented inhibitory effect of NPY on the chronotropic response to parasympathetic stimulation was confirmed and similar inhibition of the inotropic response to both sympathetic and parasympathetic stimulation was demonstrated. Since there was no modulation of the inotropic effects of exogenous a-and a1-adrenoceptor or H2-receptor agonists, it is concluded that the effects of NPY on myocardial contractility are exerted presynaptically.

SummaryA survey of 565 senior schoolchildren showed that 41% took the school meal. It provided 27% of the daily recommended energy intake and 35% of the daily protein intake set by the Department of Health and Social Security. Of the children who did not take the school meal 4% had a meal which compared favourably with it, though an equal number ate no lunch at all. The remainder either brought snacks from home or bought foods which were found to be both low in protein, iron, and calcium, and high in sugar. Sweets and chips provided the main source of energy for 9% of the subjects. IntroductionThe survey was undertaken during January and February 1972 at a large comprehensive school in London. The purpose was to find the source, the nutritional value, and the cost of the midday meal of senior schoolchildren.

1 The P-adrenoceptor antagonist activity of propranolol, metoprolol, atenolol and butoxamine in anaesthetized cats has been measured and compared with the activity of four synthetic phenylethanolamine derivatives. 2 The effects of isoprenaline on four parameters in the anaesthetized cat: heart rate, blood pressure, soleus muscle contractility and airway reactance, were measured and the modification of the isoprenaline dose-response relation by each of the antagonist drugs assessed. 3 Parallel shifts in log dose-response curves for isoprenaline were caused by propranolol for all parameters, by metoprolol and atenolol for each parameter except blood pressure, and butoxamine for each except soleus muscle and heart rate. 4 Selectivity of action of the antagonists between different organs was measured by comparing DR10 values, computed from isoprenaline dose-ratios. 5 Propranolol was the most potent antagonist and showed slight selectivity of action on soleus muscle compared with heart. Atenolol and metoprolol were approximately equipotent and were cardioselective at low doses only. Butoxamine was the least potent antagonist and possessed non-0-adrenoceptor effects on the parameters measured. 6 Each of the new compounds, 4'-bromo-2'-methyoxy-N-isopropyl phenylethanolamine, the 4'-chloro-and 4'-methyl analogues, and 4'-methoxy-N-t-butyl phenylethanolamine, was a potent antagonist but did not exhibit any selectivity of action.7 The results suggest no clear separation of P-adrenoceptors into Pl-and P2-subclasses in organs of the cat. There is no apparent separation of ,B-adrenoceptor-mediated effects on skeletal muscle and airways.

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