Prediction of acute renal failure after birth asphyxia.

Twenty-one babies of 34-41 weeks' gestational age with birth asphyxia (5 minute Apgar score less than or equal to 5 or umbilical artery pH less than or equal to 7.2) were studied during the first two days of life to find out whether the urinary excretion of tubular markers of renal function is of value in the early diagnosis of acute renal failure. Urinary retinol binding protein, myoglobin, and N-acetyl-beta-D-glucosaminidase (NAG), expressed as a ratio with urinary creatinine, were measured and excretion profiles repeated at 3-6 days in 15 infants and at 7-14 days in 11 infants. Plasma creatinine concentration, creatinine clearance, plasma myoglobin concentration, and fractional sodium excretion were measured where possible in asphyxiated infants. Control data were obtained from 50 healthy infants: 28 gave urine samples alone, 17 urine and blood, and five blood alone. Normal urinary values were derived from 17, 25, and three infants, respectively, for the three time periods. The number of control samples was limited for ethical reasons. Four asphyxiated infants had acute renal failure (group 1), four had tubular dysfunction without glomerular disturbance (group 2) and 13 had normal renal function (group 3). Group 1 were clearly identified by greatly increased urinary retinol binding protein (greater than 27,000 micrograms/mmol creatinine) and myoglobin (greater than 1500 micrograms/mmol creatinine) excretion measured in the first two days of life. In control infants the range of excretion of retinol binding protein within the same time period was 3 to 967 micrograms/mmol creatinine and urinary myoglobin was undetectable. Excretion of NAG failed to discriminate between groups 1 and 2. Acute renal failure occurred only in infants who had heavy myoglobinaemia. Tubular dysfunction in group 2 was transient and not accompanied by plasma electrolyte disturbances. We conclude that measurement of urinary excretion of retinol binding protein or myoglobin after birth is helpful in the early diagnosis of acute renal failure.

Intestinal permeability and lactose hydrolysis in human rotaviral gastroenteritis assessed simultaneously by non-invasive differential sugar permeation.

Changes in intestinal permeability and lactose hydrolysis have been investigated in three adults and fifteen infants with acute rotaviral gastroenteritis by differential sugar absorption. The method involves chromatographic measurement of urinary lactose, lactulose and L-rhamnose excretion following combined ingestion in an iso-osmolar test solution. All patients had abnormal intestinal permeability indicated by raised urine lactulose/L-rhamnose excretion, ratio of percentages recovered in 5 h, of 0.462 (0.100-1.227) mean and range, compared with 0.027 (0.008-0.052) for healthy controls (P less than 0.001). Ten patients also had urinary lactose/lactulose excretion ratios raised above the normal range (0.014-0.41, mean 0.258) during their acute illness, indicating impaired intestinal lactose hydrolysis. Both indices had become normal 4 weeks after the acute illness, serial investigation of five patients showing that improvement was complete much earlier. Except for the short duration these changes are similar to those associated with villous atrophy in coeliac disease. The test procedure was verified with respect to intestinal lactose hydrolysis by demonstrating a linear relationship between lactose/lactulose excretion and log jejunal mucosal lactase activity by in vitro assay (R2 = 0.95) in a further group of subjects. Differential lactose/lactulose/L-rhamnose absorption provides a non-invasive and sensitive index of small intestinal integrity of value for the interpretation of prolonged or otherwise complicated enteritis and the distinction of primary secondary intestinal lactase deficiency.

Development of an air displacement method for whole body volume measurement of infants.

An infant enclosed in a rigid-walled chamber displaces a volume of air equal to its own volume. The volume of air displaced can be estimated by the change in pressure produced by a standard reduction in the chamber's volume according to Boyle's law. An instrument embodying this principle has been developed in which the differential pressure between two identical chambers is measured during equal sinusoidally imposed volume changes in the two. Problems arising from variable departure of conditions of pressure cycling, from isothermal towards adiabatic, have been dealt with by empirically derived corrections. Data are presented on the use of the method for low birth-weight infants.

Peripheral blood leucocyte zinc depletion in babies with intrauterine growth retardation.

The zinc content of peripheral blood leucocytes from the cord blood of 63 normal and 20 preterm babies, and of 27 babies with evidence of idiopathic intrauterine growth retardation (IUGR) was measured. Leucocyte zinc depletion was present in babies with acute IUGR (IUGR babies compared with controls, mean 47.8 v 51.5 ng zinc/mg dry weight), but was especially severe in those with prolonged IUGR (mean 43.2 ng zinc/mg dry weight), while preterm babies were normal (mean 51.9 ng zinc/mg dry weight). We suggest that this fetal tissue zinc depletion is caused by maternal zinc depletion, and may reflect a reduction of whole body zinc status.

Gastrointestinal permeability changes in the preterm neonate.

The lactulose/L-rhamnose urinary excretion ratio during continued infusion of milks containing both sugars was used as an index of the permeability of the neonatal bowel to large and small molecules. Healthy infants of gestational age 31-36 weeks proved to have a period of enhanced permeability to lactulose during the first week of life, the lactulose/L-rhamnose excretion ratio being significantly higher on day 2 than on days 9 or 16 when a mature pattern of permeability could be seen. In infants traumatised by asphyxia or sepsis this change was much less pronounced. Healthy preterm infants of gestational age 26-29 weeks showed a 'mature' pattern of permeability at birth, followed by a temporary period of enhanced permeability after 3-4 weeks of life. It is proposed that enhanced permeability to larger molecules is a specific temporary condition of the neonatal bowel in man as in other mammals, but the immunological implications in man remain to be established.

Idiopathic hypoglycaemia in sibs with morphological evidence of nesidioblastosis of the pancreas.

Two sibs who sustained severe hypoglycaemia in the neonatal period are reported. In spite of treatment with frequent feeds intravenous glucose, glucagon, hydrocortisone, and diazoxide, hypoglycaemia persisted, and both infants eventually required subtotal pancreatectomy. Tests for leucine toleranct were normal though the second case showed some protein sensitivity. Histological and immunohistochemical studies indicated nesidioblastosis in both specimens of pancreata. The children are presently performing at mildly retarded levels, and required diazoxide and anticonvulsant medication for some time postoperatively. Because both sexes are represetned, an autosomal recessive inheritance pattern is suggested. The theory of a gut hormone stimulating insulin production is briefly discussed.