SUMMARY We studied 91 offspring of ABO incompatible pregnancies and 30 controls resulting from 0-0 pregnancies to test whether cord bilirubin levels could be used to predict the severity of hyperbilirubinaemia in ABO incompatibility. Blood group, direct Coombs's test, and serum bilirubin estimations were carried out on cord blood, and bilirubin estimations at 12, 24, 36, and 48 hours of life.All newborns in whom the cord bilirubin was greater than 4 mg/100 ml (68 ,umol/l) developed severe hyperbilirubinaemia (levels >16 mg/100 ml (273 ,umol/l) at 12-36 hours) and required exchange transfusion. It is concluded that in ABO incompatibility infants with cord bilirubin level greater than 4 mg/100 ml represent a special 'high risk' category and should be placed in a centre where frequent re-evaluation and appropriate therapy are available.

Using weanling mice of two different genetic strains we demonstrated a potentiation of the toxic effects of acetaminophen by prior infection with influenza B virus. The C57BL/6N (B6) strain of mice is genetically predisposed to increased toxicity from acetaminophen when the hepatic cytochrome P-450 mixed function oxidase system is preinduced. When B6 animals are pretreated with influenza B virus and an mixed function oxidase system inducing agent before administering acetaminophen, we observed a significant incidence of atypical "fatty" liver pathology on light microscopy similar to the microvesicular steatosis seen in human Reye's syndrome. Electron microscopic changes in the liver of these animals resemble those published to date in human Reye's syndrome.

The factor in serum that modifies the cardiac-inhibitory effects of DOC appears to be associated with a protein molecule having a molecular weight of 60,000–70,000. Heating the albumin fraction destroys its activity. Dialysis of serum indicates that one or more dialyzable cofactors are required for full activity of the serum. Of a number of compounds tested for their ability to antagonize DOC, l-cysteine is the most effective while glutathione and dl-homocysteine show slight activity. A study of a number of steroids related to DOC and progesterone revealed that the 21-hydroxy configuration is necessary for cardiac stimulation while progressive reduction at C-11 increases the cardiac inhibiting property of the steroid.