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ABSTRACT

The effects of human serum and ethylenediaminetetraacetate (EDTA) on the precipitation stage of a double-antibody immunoassay for insulin have been studied. Human serum consistently reduced the rate of precipitation of bound insulin by rabbit antiserum and the results obtained with modified human serum suggested that this effect was due to complement. Under certain conditions, EDTA was found to accelerate the precipitation of antibody-bound insulin and some implications of this finding to the double-antibody method of assay are considered.

ABSTRACT

Pregnancy sera, cord sera and placental homogenates were applied to Sephadex G-100 and the human chorionic somatomammotrophin (HCS) concentrations in the eluates were estimated by radioimmunoassay. Two HCS peaks were obtained when maternal serum or placental homogenates were used. The minor component, representing 0.5% – 3.0% of the total HCS recovered, appeared to have a molecular weight of about 45 000 and the major component a molecular weight of 21 500. The two HCS components were found under a variety of conditions and it appears that a small proportion of serum HCS may be in a dimeric form.

Abstract

This paper reviews the outcome in 12 children with hyperinsulinaemic hypoglycaemia who first developed symptoms between the ages of 2 and 8 months and who were treated with diazoxide (5 - 20 mg/kg/day) for 2-13 years. Two cases required subtotal pancreatectomy at the ages of 5 and 10 years because of recurrent hypoglycaemia and one girl with severe retardation died at the age of 6 years while still on diazoxide therapy. Two patients aged 3.5 and 9 years are still on treatment and in 7 cases diazoxide was discontinued between the ages of 2.5 and 14 years, indicating that spontaneous remission can be expected in a high proportion of children with post-neonatal hyperinsulinaemic hypoglycaemia. Of the 9 children who started diazoxide within 3 months of the onset of symptoms, 5 are of normal intelligence and 4 are moderately retarded (IQs 63-71). In 3 children diazoxide was started 8 months to 3 years after the onset of symptoms; two are retarded (IQs 60-70) and the third was severely retarded and died aged 6 years.

Abstract. The value of a 7-h water deprivation test incorporating urinary osmolality and urinary arginine vasopressin (AVP) measurements was investigated in 20 children with suspected anterior or posterior pituitary dysfunction (group A) and 11 presenting with polyuria and polydipsia (group B). A control group of 16 healthy children was also studied. Urinary osmolalities in the control subjects after 7 h of water deprivation were 827–1136 mosmol/kg and urinary AVP 114–320 pmol/l. Of the group A patients, 5 had symptomatic diabetes insipidus with urinary osmolalities < 300 mosmol/kg, and urinary AVP concentrations of < 10 pmol/l, and 5 had normal urinary concentrating ability. The other 10 patients had varying degrees of partial diabetes insipidus (urinary AVP 6–53 pmol/l) although in 3 urinary concentrating ability was well maintained (osmolality 650–747 mosmol/kg). In group B, a diagnosis of compulsive water drinking was made in 9 patients, 1 had nephrogenic diabetes insipidus (urinary osmolality 68 mosmol/kg, AVP 782 pmol/l), and the final patient had transient diabetes insipidus. The test described was easy to perform and well tolerated even in young children. Using this test alone, it was possible to identify patients with partial defects of posterior pituitary function even when urinary concentrating ability was maintained, as well as those with complete cranial diabetes insipidus, nephrogenic diabetes insipidus, and compulsive water drinking.