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Fetal acid-base status was evaluated on 66 blood samples taken for rapid karyotyping from 58 growth-retarded fetuses. Before blood sampling, doppler blood flow studies of the umbilical artery showed end-diastolic frequencies to be absent in 32 fetuses (group 1) and present in 26 (group 2). Fetuses with chromosomal (n=4) or structural (n=8) abnormalities were excluded from subsequent analysis. Gestational age at blood sampling (27·8 [95% Cl 26·5-29·1] vs32·2 [30·4-34·1] weeks) and time from sampling to delivery (median 2 (range 0-35] vs 14 [0-77] days) were significantly lower in group 1 than group 2. There were no perinatal deaths in group 2 whereas mortality in group 1 was 65·4%. There were significant differences between the groups at blood sampling in pH, pO2, pCO2, base equivalents, and nucleated-red-cell count, but within group 1 these measurements were similar in surviving fetuses and those who died perinatally. Since acid-base determination does not predict perinatal outcome in growth-retarded fetuses, fetal blood sampling has a limited role in monitoring fetal wellbeing.

In order to establish the true incidence of spontaneous multiple conception and to evaluate the phenomenon of the 'vanishing twin', the charts of the 6341 women on whom a diagnostic ultrasound was performed at between 7 and 14 weeks gestational age at the Rotunda Hospital during 1991 were reviewed. Out of 173 twin pregnancies there were 90 cases of normal ongoing twin pregnancy, 81 cases of blighted ovum or missed abortion coincident with an ongoing singleton pregnancy, and two cases of two blighted ova. Thus the incidence of multiple gestation is higher in early pregnancy than would be expected according to Hellin's law.

The effects of dopamine, noradrenaline and 3,4-dihydroxyphenylacetic acid (DOPAC) on the release of prolactin were examined in ovariectomized ewes. Infusion of dopamine (0·5 or 1 μg/kg per min for 2 h i.v.) reduced plasma prolactin concentrations in a dose-dependent manner, whereas DOPAC (5 or 10 μg/kg per min for 2 h i.v.) had no effect. In a further series of experiments, ovariectomized hypothalamo-pituitary disconnected ewes were given dopamine or noradrenaline (each at 0·5 or 1 μg/kg per min for 2 h i.v.), and both amines reduced mean plasma concentrations of prolactin with similar potency in a dose-dependent manner. These effects were blocked by treatment with pimozide and prazosin respectively. During the infusion of dopamine, the peripheral plasma concentrations of DOPAC and 3,4-dihydroxyphenylethyleneglycol (DHPG) were increased (DOPAC, 22 ± 7 (s.e.m.) to 131 ± 11 nmol/l; DHPG, 2·9 ± 0·3 to 6·4 ± 0·2 nmol/l), but plasma concentrations of dopamine and noradrenaline did not change. Finally, administration of domperidone, a specific dopamine receptor antagonist that does not cross the blood-brain barrier, resulted in a sustained increase in plasma prolactin concentrations in ovariectomized ewes. We conclude that the secretion of prolactin from the pituitary gland is under dual inhibitory regulation by both dopamine and noradrenaline in the sheep.Journal of Endocrinology(1989) 123,393–402

The amino acids taurine and glycine are odorants that activate specific chemosensory cells in the olfactory sensilla (aesthetascs) of the spiny lobster, Panulirus argus. We show that the aesthetascs themselves contain large intracellular concentrations of taurine (≈2 mM) and glycine (≈ 85 mM); these concentrations are more than 10,000-fold greater than the response thresholds of the chemosensory cells. A net efflux of at least five amino acids occurs when the olfactory organ is immersed in amino acid-free seawater. With taurine and glycine, efflux continues until an apparent equilibrium is reached between the sensilla and the external medium; for taurine the equilibrium with seawater occurs at ≈12 to 28 nM, and for glycine at ≈100 to 500 nM. Aesthetascs may achieve these equilibria within 300 ms. Hence, even during the brief interval between consecutive flicks of the antennule, olfactory receptors are exposed to a background of odorants escaping from intracellular stores. Electrophysiological studies show that both the spontaneous and evoked activities of taurine-sensitive chemosensory cells are markedly affected by a taurine background simulating that measured in the efflux studies. Uptake systems may participate in establishing the equilibria between sensilla and seawater since (1) the net efflux of amino acids increases in sodium-free seawater; and (2) guanidinoethane sulfonate, a competitor for taurine uptake, selectively increases net taurine efflux. Effluxes from an olfactory organ may contribute noise to the chemosensory process; alternatively, background substances could contribute functionally by affecting membrane proteins.

Background: The high prevalence of clinical latex allergy and latex sensitization in children with meningomyelocele has been widely reported. It has also been noted that these same children have a higher than expected prevalence of atopic disease. It would be useful to have a safe, sensitive, and specific skin test to detect latex sensitivity and to know how well this test compares with available in vitro tests. It would likewise be helpful to know as fully as possible the characteristics of the individual and to evaluate the relative importance of factors suspected to contribute to clinical latex allergy and latex sensitization in this population. Methods: A group of 116 children and adolescents 1 to 20 years of age were recruited for the study. An extensive history of latex allergy, atopic diseases, and surgical procedures was taken on all subjects. Each subject had either a latex skin test or an in vitro study for latex-specific IgE, and 67 subjects had both tests simultaneously. Eighty-five subjects had epicutaneous skin tests to a panel of environmental allergens. Results: Overall, 25 of 116 (21.5%) subjects had a history of clinical latex allergy, and 51 of 116 (44%) were sensitized to latex. The sensitivity and specificity of skin tests for clinical latex allergy were slightly greater than for the in vitro test (100% vs 95.8% and 82.3% vs 68.9%, respectively). The positive predictive value and negative predictive value of skin testing for clinical latex allergy were also greater (67.6% vs 50% and 100% vs 98.1%, respectively). Age was found to be a significant variable for both latex allergy and latex sensitization. The number of surgical procedures undergone and the presence of positive skin test responses to environmental allergens were significantly correlated with latex sensitization but not with clinical allergy to latex. Conclusions: A sensitive, specific, and safe skin test for latex sensitivity appears superior to in vitro testing for latex allergy. Age, number of surgical procedures, and the presence of positive allergen skin test responses are significantly correlated with latex sensitization. Age alone is significantly correlated with clinical allergy to latex. (J Allergy Clin Immunol 1998;101:741-6.)

The concentrations of dopamine, noradrenaline and their respective primary neuronal metabolites 3,4-dihydroxyphenylacetic acid (DOPAC) and 3,4-dihydroxyphenylethyleneglycol (DHPG) were measured in the hypophysial portal and peripheral plasma of sheep and rats by combined gas chromatography–mass spectrometry. Hypophysial portal and jugular blood samples were taken at 5- to 10-min intervals for 3–7 h from six conscious ovariectomized ewes. Blood was also collected for 30 min under urethane anaesthesia from the cut pituitary stalk from 16 pro-oestrous female and five intact male rats.In ovariectomized ewes, noradrenaline concentrations were higher in hypophysial portal plasma than in peripheral plasma (6·6 ± 0·8 vs 2·2 ± 0·4 nmol/l). In contrast, dopamine was undetectable (<1 nmol/l) in the portal and peripheral plasma of all ewes. Plasma levels of DOPAC and DHPG in portal and jugular samples were similar. In all pro-oestrous female rats, plasma concentrations of dopamine were higher in portal blood than in jugular blood (8·0±1·4 vs 4·8± 0·6 nmol/l). Detectable concentrations of dopamine were measured in the portal plasma of two out of five male rats. Noradrenaline concentrations were higher in portal plasma than in peripheral plasma of both female (8·3 ± 1·7 vs 3·7 ± 0·6 nmol/l) and male (14·8± 2·7 vs 6·1± 1·2 nmol/l) rats.These data show that noradrenaline, but not dopamine, is secreted into the long portal vessels in sheep. The results suggest that there are species differences in the secretion of hypothalamic dopamine into hypophysial portal blood.Journal of Endocrinology(1989) 121,141–147

Cervicography was performed on 223 occasions on 211 patients undergoing colposcopy. The final diagnosis was based upon the histology of any biopsy taken or on the cytology of the cervical smear. The sensitivity and specificity of cervicography in this pilot study were encouraging. The cervigrams were very valuable for teaching and review.