The Distribution of S³⁵-Labeled Bovine Serum Albumin in Newborn and Immunologically Tolerant Adult Rabbits

The fate of injected S³⁵-labeled sulfanilic acid-azoalbumin in the serum, various organs, and liver fractions was compared in the newborn and adult rabbit and in specifically unresponsive and normal adult rabbits. Exponential decay of the injected antigen without the usual immune phase of elimination was observed in newborn and unresponsive adult animals. Comparison of organ distribution of radioactivity in adults and animals injected at birth and 21 days of age showed persistence in the liver at least as long as 3 weeks in all groups (which was the time chosen for observation). The slight differences in spleen and thymus concentrations with age are of undetermined significance. Comparison of the organ distribution of antigen in unresponsive adult rabbits and in normal ones showed slight differences which were similar to those predicted from previous immunization of adults which gave low grade antibody response. There was a slight selective accumulation of antigen in the nuclear fraction of liver homogenates of unresponsive animals, but no other differences were observed

Platelet dysfunction and coagulopathy in intraventricular hemorrhage in the premature infant

We investigated platelet count, bleeding time, platelet aggregation, prothrombin time, activated partial thromboplastin time, and fibrinogen level in 58 very low-birth-weight infants during the first postnatal day to determine the relationship between hemostatic disorders and intraventricular hemorrhage. Thirty-two of the 58 infants (55%) were found to have periventricular-intraventricular hemorrhage by computerized tomography or autopsy. Nine patients (16%) had subarachnoid hemorrhage only and 17 (29%) had no evidence of intracranial hemorrhage. Infants with IVH had a significantly lower mean platelet count than did infants with no SAH/IVH. However, only five patients with IVH had initial thrombocytopenia. The IVH group had a mean bleeding time which was significantly prolonged compared to that of the group without SAH/IVH. Similarly, patients with IVH had a mean platelet aggregation response which was significantly diminished in comparison to that of patients with no SAH/IVH. Infants with IVH had a significantly longer mean PT than did infants with no SAH/IVH. In addition, babies with IVH had a significantly longer mean APTT compared to that of babies without SAH/IVH. The groups did not differ significantly with respect to fibrinogen levels. Three infants with IVH had disseminated-intravascular coagulation in the early neonatal period. These data suggest that disorders of platelet-capillary interaction and defects in the intrinsic and extrinsic coagulation pathways may play important roles in intraventricular hemorrhage in the premature infant