Which three-year-olds attend preschool facilities?

In an epidemiological survey of a total population of three-year-old children living in a London borough, information was obtained on the behaviour, development and social characteristics of 828 children. Details were extracted from the registers of 27 preschool facilities in the borough (a residential nursery, day nurseries, play groups and nursery schools and classes) on all children attending over an 18-month period. The patterns of attendance and factors influencing attendance of about 3000 children are discussed. The comparison of children attending facilities in the original sample of 828 with the total sample shows that those children most in need are not over-represented in these preschool groups.

Altered cardiac responsiveness and regulation in the normal cardiac output type of borderlind hlpertension

Of 145 patients with borderline hypertension, 30% had increased resting cardiac index (QI), whereas the remainder had normal values. The specific aim of this study was to investigate cardiac regulation in patients who had normal resting QI. Eighty-five control subjects were used for comparison. At rest, patients with normal QI showed evidence of decreased parasympathetic inhibition; the QI after injection of atropine increased less than in control subjects. After complete cardiac autonomic blockade with propranolol and atropine, QI and stroke volume were significantly lower in patients than in control subjects. The mechanism of this low QI was further analyzed. Central blood volume, which strongly correlates with stroke volume, was used as an estimate of the cardiac venous filling. After blockade, stroke volume was decreased in patients, but central blood volume was normal. Patients also showed a decreased heart rate and QI response to infusion of isoproterenol. It is therefore postulated that two components may be responsible for the low QI in the "denervated" heart: patients exhibit a decreased responsiveness to sympathetic stimulation, and they may also be less responsive to venous filling. Behind the facade of cardiac normality in these borderline hypertensive patients with normal cardiac output, there is evidence of altered autonomic control of the heart (decreased vagal inhibition) and of changed cardiac response to sympathetic stimulation and possibly to venous filling.

Effect of high dose spironolactone and chlorthalidone in essential hypertension: relation to plasma renin activity and plasma volume

The effect on blood pressure of high (400 mg/day-S400) and moderate dose (200 mg/day-S200) spironolactone and chlorthalidone (100 mg/day-C100), given in a random double-blind manner was related to plasma renin activity and plasma volume in 38 essential hypertensives. The fall in pressure from a control of 154/103 mm Hg was essentially the same after four weeks of each drug--S400 deltaBP 24/13 mm, S200 18/9 mm, C100 17/12 mm (all P less than 0-001). Twelve of 37 patients (32%) had low initial renin, but this appeared as responsive to the chlorthalidone stimulus as that of the normal renin group. The antihypertensive effect of all regimens was unrelated to plasma renin activity. Plasma volume was significantly lowered at the end of each treatment period, but the decline could not be correlated with blood pressure effects. Patients with initially low plasma volume were more likely to respond to S400 (r = 0-545, P less than 0-001), whereas the antihypertensive effect of the S200 and C100 regimens was independent of this variable.

The helminth parasites of the sheathbill, Chionis alba (Gmelin), and the diving petrels, Pelecanoides georgicus (Murphy and Harper) and P. urinatrix (Gmelin), at Bird Island, South Georgia

Twelve sheathbills, Chionis alba, 12 South Georgian diving petrels, Pelecanoides georgicus, and 5 common diving petrels, P. urinatrix, collected at Bird Island, South Georgia, were examined for helminth parasites. These appear to be the first helminthological examinations of birds from South Georgia. Eleven of the 12 sheathbills were infected with helminth parasites and the pattern of infection of adult male and female birds was similar. Five species of helminths were found in sheathbills, namely Gymnophallus dellciosus, Notocotylus chionis, Paramonostomum signiensis, Lateriporus australis and Corynosoma hammani. Two species, namely Tetrabothrius sp. and Stegophorus heardi, were found in both Pelecanoides georgicus and P. urinatrix.

The helminth parasites of whales and seals in the Antarctic and Subantarctic have been extensively studied, while in comparison those of birds from these regions have been neglected. As far as we are aware there are no previous reports on helminth parasites from the sheathbill, Chionis alba (Gmelin), the South Georgian diving petrel, Pelecanoides georgicus (Murphy and Harper), and the common diving petrel, P. urinatrix (Gmelin), from South Georgia.

The longevity of some species of helminth parasites in naturally acquired infections of the lesser black-backed gull, Larus fuscus L., in Britain

1. Ninety-six lesser black-backed gulls, Larus fuscus L., captured at about 6 weeks of age, were kept in captivity for up to 2⅛ years. At intervals some gulls were killed and examined for helminth parasites, of which 14 species were found comprising 4 species of Trematoda, 5 species of Cestoda and 5 species of Nematoda.

2. Nine of the 14 species are commonly found in Holarctic gulls and may be regarded as characteristic members of the helminth fauna of these birds. Six species are recorded from L. fuscus for the first time.

3. The life span of different species of helminth parasites in L. fuscus varied from 2 months to 2⅛ years; few specimens lived in their host for more than one year. During captivity there was a marked decline in the variety of the helminth fauna of individual gulls, as well as a general decline in the incidence and intensity of infection with individual species of parasites. There was one exception, the tape-worm Tetrabothrius cylindraceus, which increased in incidence and maintained a fairly even intensity of infection in L. fuscus over 21 months. The results are discussed in relation to the ecology of the parasite and the host.