Summary Extraction of unbound bilirubin by Sephadex gel filtration and measurement by a micro‐method were carried out in 45 sera from jaundiced newborns (hemolytic disease or prematures). In about half the cases some free bilirubin with values in the range 0.1 to 1 mg/100 ml was detected. Levels above 0.5 mg/100 ml were exceptional (only 2 cases). Five autopsies were performed in prematures with unbound bilirubin levels above 0.1 mg/100 ml, and one kernicterus was found. Two infants with unbound bilirubin levels of more than 0.5 mg / 100 ml had clinical symptoms of kernicterus. No symptoms of kernicterus were observed in infants with high total bilirubin together with an insignificant amount of unbound bilirubin. The main interest of this method lies in the direct assessment of a toxic element originating from varying bilirubin and albumin levels and the micro‐environment of the bilirubin‐al‐bumin binding. But other factors, such as the cell membrane permeability and/or the duration of exposure, are likely to play a prominent role.

β‐mannosidosis is a recently described inherited disorder with predominantly neurological signs and symptoms as the major manifestations of the disorder. The heterogeneous manifestations of the disease have been presented in seven previous patients. We describe a further case of European descent with an infantile onset of the disease, with the features of speech impairment as the first symptom, β‐mannosidase activity was completely deficient in the patient and a heterozygote level was found in the parents. In addition, mannosyl‐N‐acetylglucosamine was identified in the patient's urine in keeping with the diagnosis of β‐mannosidosis.

Free bilirubin (FB) and total bilirubin (TB) were determined in 154 samples of blood taken from 112 jaundiced newborns: 51 prematures without hemolysis (19 of these with RDS); 26 full terms presenting AB0 incompatibility; 35 newborns (both prematures and full terms) presenting rhesus incompatibility. Kernicterus was observed in seven cases and only three occurred in the TB group above 20 mg/100 ml; 57 cases had FB equal to or above 0.1 mg/100 ml and all kernicterus fell into this category. In the other 55 cases in which FB was less than 0.1 mg/100 ml no kernicterus was observed. In the group of healthy fullterm newborns presenting AB0 incompatibility, 15 had FB above or equal to 0.1 mg/100 ml ranging between 0.1 and 0.4 mg/100 ml; however no kernicterus was observed during the neonatal period. On the contrary, in the group of prematures a little more than half of the cases had a FB ranging from 0.1 to 0.4 mg/100 ml whereas four macroscopic kernicterus cases were observed. The difference between the two groups compels us to consider other factors than those acting on the albumin-bilirubin binding especially those acting on the blood-brain barrier and on the fixation of the pigment by the neurons. A second series of 605 consecutive autopsies, on a period of 10 years, on prematures excluding light-for-dates and cases of hemolysis, evaluates the distribution of 40 kernicterus as a function of birth weight. On this second series kernicterus appears with maximal frequency for birth weight between 1,000 and 1,250 g, with a nonnegligible frequency at 1,500 to 2,000 g and was absent between 2,000 and 2,500 g. 13 kernicterus were observed for a peak TB below 12 mg/100 ml. These results seem to justify a systematic determination of FB in the premature weighing less than 2,000 g from the 24th hour of life whether he has jaundice or not.

ExtractFibrinogen and factors V, II, and VII + X assays were performed by micromethod on days 1, 2, 3, and 10 of life in 96 premature infants ( <37 weeks gestational age). "Sick" premature infants, mainly with respiratory distress syndrome, were compared with premature infants considered to be thriving. In the thriving infants, the mean level of the studied clotting factors appears to be independent of gestational age. Fibrinogen and factor V levels are correlated in thriving as well as in sick infants; both are significantly decreased in the sick infant group. In both groups, factors //and VII + Xlevels were consistently low on the 1st day of life. They progressively increased but did not reach adult levels by the 10th day of life despite routine vitamin K x administration. Overall mortality as well as clinical hemorrhagic manifestations were closely related to blood clotting factor levels. Pathologic and biologic data indicate a relation between coagulation abnormalities in premature infants and the occurrence of disseminated . intravascular clotting. SpeculationIt can be postulated that low levels of blood clotting factors result from either diminished production (immaturity, toxicity, etc.) or increased utilization or consumption (i.e., disseminated intravascular coagulation (DIG)). Hypercoagulability and disseminated intravascular coagulation have been described in premature infants, especially in those with respiratory distress. By means of microtechnics, it is now possible to study the evolution of blood clotting factor levels in premature infants with and without respiratory distress in an attempt to better understand the relation of blood clottinglevels and the presence of DIC. Introductionlarly useful for analysis of the rapid changes in the