SummarySeventy-five children aged 3 weeks to 12 years and found on investigation of symptomatic urinary infection to have vesicoureteric reflux were managed conservatively with continuous low-dose prophylaxis. Serial cystographic and renal growth studies were performed during seven to 15 years' follow-up.Reflux disappeared spontaneously in 53 children (71 %) and from 79% of the affected ureters. This occurred at any age and not only in infancy or at puberty. The initial severity of reflux was the most important factor affecting the outcome. Reflux disappeared from 85% of ureters of normal calibre but from only 41 % of dilated ureters. Gross reflux associated with existing severe renal scarring was least likely to disappear. Nevertheless, reflux stopped in 12 of the 19 initially scarred renal units (63%). Reflux was as likely to disappear in children who had a recurrence of urinary infection as in those who had no further infection. Renal growth appeared to be normal in 93% of kidneys and fresh or extending scarring was seen in only two children.Management programmes for children with vesicoureteric reflux should take into account the self-limiting nature of three-quarters of the reflux found on investigating uncomplicated urinary tract infection.

In a study of the factors surrounding the development of renal scars clinical data and serial radiographs were analysed in 74 infants and children (66 girls and eight boys) without duplex kidney or obstruction. The development of new scars was seen radiologically in 87 kidneys (74 previously normal and 13 previously scarred). New scarring was extensive in 16 kidneys. Thirty four children were aged 5 or over when scarring occurred.

Infection of the urinary tract is a common condition in childhood and one which is often overlooked. In a recent large survey significant bacteriuria was found in 1% of a schoolgirl population, many of these children being symptomless (Kunin et al., 1962). De Luca et al. (1963 found an average delay in diagnosis of 18 months, and only 28% of Burke's (1961) Necropsy information is available in one infant dying at 6 weeks. In 12 children, nine of them newborn, investigation was not carried out either because permission was refused or they were lost to follow-up soon after the initial illness.

SUMMARY1. Two sets of experiments were performed on intact foetal lambs exteriorized at Caesarean section; in one set radioactively labelled test substances (inulin, sucrose, mannitol, erythritol, urea) were injected I.V. either singly or in pairs and then followed in plasma, lung lymph and alveolar liquid; in the other set labelled test substances (inulin, sucrose, mannitol, erythritol, D-serine, L-serine, D-a-alanine, urea, water, thiourea, N-ethylthiourea) were introduced singly, in pairs, or sequentially into alveolar liquid and their concentration followed in alveolar liquid and plasma.2. Inulin was found to cross lung capillary walls but not alveolar walls. Measurements of its concentration following injection into alveolar liquid were used to determine the volume of foetal alveolar liquid (mean = 30 ml./kg) and its rate of formation (mean = 0-036 ml./min. kg). The volume of the lung interstitial space was determined from previous experiments in which [1251]PVP had been injected I.v. then measured after 2 hr in lung tissue and lung lymph (mean = 10 4 % foetal lung weight after withdrawal of liquid; . 20 % wet lung tissue weight).3. Transfer constants (min-') for lung capillaries (Kc) and alveoli (KO) were obtained from the experimental results by compartmental analysis. Permeability constants (PC and Po, cm/sec) were derived from them using estimates for capillary and alveolar areas. For lipid insoluble molecules Pc and PO both increased with decreasing molecular radius, the effect being much greater for PO than Pc. Po was also shown to increase with lipid solubility of the test molecule even though molecular size increased with lipid solubility in the series tested (urea, thiourea, N-ethylthiourea).

1. Lymph from the lungs of lambs and sheep was found to enter both the right lymph duct and the thoracic duct. Right lymph duct flow was collected by constructing a venous sac, the venous tributaries of which were ligated but which the right lymph duct entered; thoracic duct flow was collected by cannulating the duct. Lymph from sites other than the lungs was excluded from the collections.2. Measurements were made of the surface tension characteristics of lung extracts and of the liquid present in foetal lungs. These values were used together with gestational age and crown-rump length to designate the foetal lambs into mature and immature groups.3. Lymph flow from the lungs averaged 0.99 ml./kg body wt./hr in immature foetal lambs, and 1.81 ml./kg/hr in mature foetal lambs before the start of ventilation. Lymph flow from the lungs of spontaneously delivered new-born lambs (mean age 51 hr) averaged 0.86 ml./kg/hr. In adult ewes right lymph duct flow averaged 0.11 ml./kg/hr and total lung lymph flow was estimated indirectly to be 0.33 ml./kg/hr. Calculated rates of protein flow in lung lymph (flow x protein concentration) were greater in foetal lambs than in adult sheep.4. Total thoracic duct flow averaged 2.48 ml./kg/hr in immature foetal lambs, 5.30 ml./kg/hr in mature foetal lambs, 3.65 ml./kg/hr in new-born lambs, and 2.92 ml./kg/hr in adult ewes.5. At the start of ventilation there was an increase in lymph flow from the lungs, which at 15-30 min reached a mean of 6.4 ml./kg/hr in mature lambs and 2.6 ml./kg/hr in immature lambs. At the same time the protein concentration of lymph decreased but the calculated protein flow increased.6. The lungs of foetal lambs weighed more than the lungs of spontaneously delivered new-born lambs, and the difference could be accounted for by liquid which could be aspirated through the trachea of the foetal lamb. On ventilation of the lungs for 2 hr, without first allowing the escape of any lung liquid, lung weight measurements indicated that about 66% of the lung liquid had been taken up in mature lambs and about 50% in immature lambs.7. It was concluded that the rate at which lymph is formed in the lungs is greater per kilogram body weight in foetal than in new-born lambs and greater in them than in ewes. The increase in lymph flow at the start of ventilation could account for the removal of about 40% of the liquid present in the lungs of the mature foetus and about 25% of the liquid in the lungs of the immature foetus.