First ladies in laying the foundation of neuroendocrinology.

Although women were welcomed into medical practice in increasing numbers by the close of the nineteenth century, it was not until the second quarter of the twentieth century that they were recognised as valuable collaborators and contributors in the nascent field of neuroendocrinology, wherein they soon made advances that have stood the test of time. Mary Pickford at Edinburgh measured the action of acetyl choline in the supraoptic nucleus of the hypothalamus and helped to establish that vasopressin and oxytocin are formed in separate and distinct neurons. Berta Scharrer, like her future husband Ernest Scharrer, was born in Munich. Their great contribution was the proof that the posterior pituitary is not a gland, but the location of the release into the circulation of vasopressin and oxytocin from fibres in the hypothalamico-hypophysial tract. Their work succeeded in establishing against high-powered, vehement opposition the value of histological evidence in elucidating synthesis, storage and release of secretion from neuro-endocrine cells. A Rockefeller travelling fellowship allowed Marthe Vogt to move from Berlin in 1932 to London and then to Cambridge. The relations between the cortex and medulla of the suprarenal gland and the control of adrenocorticotropin were her main concerns. Dora Jacobsohn emigrated to Sweden after graduating in Berlin in 1934. She investigated control of the anterior pituitary gland by the hypothalamus, and co-operated with Geoffrey Harris in establishing the role of the hypothalamico-hypophysial portal venous system that conveys the releasing factors that preside over anterior pituitary cells. Laboratory discoveries do not constitute the whole of science, for the interpretation of evidence and recognition of general principles deserve attention. Dorothy Price, from Aurora, Illinois, received her BS in 1922 at the University of Chicago, and was glad to find employment as a histology technician in the zoology laboratory, where she was quietly appropriated by Carl Moore (1892-1955), an investigator seeking the key to hormonal control of gonadal function. The burning question was the part played by what was (then) called hormone antagonism in the biology of the testis. Price recognised that the common factor in explaining the deleterious effects of oestrin and testosterone on the testes could be traced to the anterior pituitary: the pituitary controlled testicular secretion, and the male hormone in turn controlled gonadotropin release in the pituitary. This seesaw balance explained the problem, and was the first of many regulatory systems to be recognised as ensuring stability--and later became known as negative feedback. The contributions of these five women helped place neuro-endocrinology on a firm foundation for its later expansion.

William Wilde and the early records of consumption in Ireland.

Absence of documentary or bony evidence before the seventeenth century in Ireland is not conclusive evidence of freedom from tuberculosis. Clear records begin with Bills of Mortality kept in Dublin, the city at the centre of English administration of Ireland, and they show that the basis for an epidemic was firmly established therein before 1700. In the middle of the nineteenth century the cataclysmic Famine opened the floodgates of poverty and urban overcrowding that resulted in an alarming death rate that continued to increase until the early years of the twentieth century. It is to William Wilde (1815-1876) we owe the nuanced investigation of the earliest numerical records of consumption and related disorders in Ireland.

Glucocorticoid treatment reduces exhaled nitric oxide in cystic fibrosis patients.

In cystic fibrosis (CF), low concentrations of exhaled nitric oxide (NO) and reduced expression of inducible nitric oxide synthase (iNOS) in airway epithelium have been reported. However, abundant iNOS expression has been found in the subepithelial tissues and elevated concentrations of NO metabolites in breath condensate and sputum. These conflicting results may be explained by increased scavenging of NO by superoxide radicals, resulting in rapid conversion to peroxynitrite, so that only a small proportion of the NO produced in the lung tissue reaches the airway lumen. If iNOS were active in the CF lung, exhaled NO would be further reduced by glucocorticoid treatment. CF patients (n = 13) were recruited to a double-blind, placebo-controlled study with crossover. Treatment comprised prednisolone or placebo for 5 days with a 9 day washout. After each treatment, exhaled NO was measured, spirometry performed and blood collected for measurement of serum nitrogen dioxide/nitrous oxide (NO2/NO3). Ten patients (8 male) completed the study. Following prednisolone treatment (mean +/- SD) exhaled NO concentration (3.1 +/- 1.6 parts per billion (ppb)) was significantly reduced versus placebo treatment (4.9 +/- 4.2 ppb; p<0.05, Wilcoxon signed-rank test). Spirometric indices and serum NO2/NO3 concentration were unchanged. These findings support the hypothesis that glucocorticoids suppress nitric oxide production in cystic fibrosis airways by reducing inducible nitric oxide synthase expression or by inhibiting recruitment of neutrophils, cells which express inducible nitric oxide synthase.

Changes in male:female ratio among newborn infants in Ireland.

Trends in the male proportion of live births in Ireland were examined by extracting the numbers of male and female live births from Registrar General's Reports (1864-1952) and Department of Health Annual Reviews (1953-1996), and subjecting them to statistical analysis. Except for 10 years (1947-1956) the proportion of male births has risen, significantly so since 1957. The global fall in male proportion of live births in recent decades has not been seen in Ireland, even though the country has undergone progressive industrialisation. It would be prudent not to assume that the same environmental factors alter sex ratio and cause pathological changes in male reproductive organs.

Total sputum nitrate plus nitrite is raised during acute pulmonary infection in cystic fibrosis.

Nitric oxide (NO) can be detected in exhaled gas in human subjects. It is produced by nitric oxide synthase (NOS) and is rapidly metabolized to nitrite and nitrate (NO2/NO3). Exhaled NO is reported to be elevated in patients with asthma, bronchiectasis, or upper respiratory tract infection. Recent reports have shown no increase of exhaled NO in stable cystic fibrosis (CF). We hypothesized that NOS activity is increased in patients with acute pulmonary exacerbation of CF. We therefore measured exhaled NO and sputum NO2/NO3 in three subject categories: patients with acute pulmonary exacerbation of CF, patients with stable CF, and healthy control subjects. Mean +/- SD exhaled NO was significantly higher in control subjects (8.8 +/- 4.9 ppb) than in both acute (3.8 +/- 3.9 ppb) and stable (5.0 +/- 2.5 ppb) patients. Sputum NO2/NO3 was significantly higher in acute patients (774 +/- 307 micromol/L) when compared with both stable patients (387 +/- 203 micromol/L) and control (421 +/- 261 micromol/L) subjects. Sputum NO2/NO3 did not return to normal in a subgroup of patients assessed after 2 wk of intensive antibiotic and glucocorticoid treatment. These results confirm that exhaled NO is not a useful measure of airway inflammation in CF. Elevated levels of sputum NO2/NO3 suggest that NOS is activated during acute pulmonary exacerbations of CF.

Gentle exercise with a previously inactive muscle group hastens the decline of blood lactate concentration after strenuous exercise.

The aim of this study was to elucidate the mechanism by which the disappearance of blood lactate following severe exercise is enhanced during active recovery in comparison with recovery at rest. Rates of decline of arterialised venous blood lactate concentrations in man after maximal one-leg exercise were compared during four different modes of recovery: passive (PR), exercise of the muscles involved in the initial exercise (SL), exercise of the corresponding muscles in the hitherto-inactive leg (OL), or exercise of one arm (RA). Recovery exercise workloads were each 40% of the onset of blood lactate accumulation (OBLA) for the limb used. In comparison with PR, SL and OL accelerated the fall in blood lactate to similar extents whereas RA was without effect. The first-order rate constant (min-1) for decline of arterialised venous blood lactate concentration after the intense exercise was 0.027 (0.003) in PR, 0.058 (0.025) in SL, 0.034 (0.002) in OL, and in RA was 0.028 (0.002) [mean (SEM), n = 6 subjects]. Preliminary studies had shown that RA in isolation elevated blood lactate whereas SL and OL did not. Thus, with appropriate workloads, exercise of either hitherto active or passive muscles enhanced blood lactate decline during recovery from intense exercise. This suggests that the effect resulted principally from the uptake and utilisation of lactate in the circulation by those exercising muscles rather than from increased transport of lactate to other sites of clearance by sustained high blood flow through the previously active muscles.

Acetazolamide-insensitive carbonic anhydrase activities in liver and tonic skeletal muscle of adult male rats with streptozotocin-induced diabetes mellitus.

One of the four discrete isoenzymes of carbonic anhydrase hitherto characterized, CA III, has the lowest turnover rate and the greatest resistance to inhibition by sulphonamides. Streptozotocin-induced diabetes mellitus resulted in a reduction in acetazolamide-resistant activity of carbonic anhydrase in the liver, but not in tonic skeletal muscle, of adult male rats. The hepatic activity declined with apparent first-order kinetics [calculated rate constant (k) 0.089 day-1] to a minimum of approx. 6% of control values; the reduction in activity was moderated by administration of insulin.

Carbonic anhydrase activity in mammalian skeletal and cardiac muscle.

1. The presence of extravascular carbonic anhydrase activity in skeletal muscle, and its absence from cardiac muscle, were demonstrated in the rat. 2. The activity in skeletal muscle is approximately correlated with the proportion of dark fibres present in the middle fibre bundles.

Relationship between maturity and isoenzymes of erythrocytic carbonic anhydrase in newborn infants.

The present study was carried out to assess the activities of all three principal isoenzymes of human erythrocytic carbonic anhydrase (HCA) in newborn infants in relation to their estimated gestational ages. Blood samples were collected at parturition from the umbilical cords of 45 normal healthy infants. Among the samples taken before day 290 of gestation, the activity ratio (isoenzyme B: isoenzyme C) was correlated significantly with estimated gestational age. After day 290, the range of B:C activity ratios was similar to that observed in adults. Isoenzyme A represented a relatively constant proportion (mean +/- SEM) at 7.2 +/- 0.2% of total HCA activity. The B:C activity ratio appears to be a more reliable and sensitive index of maturity than either the total HCA activity or the ratio of total HCA activity to the total hemoglobin concentration in cord blood.