No abstract

Intravenous infusions of one liter of low molecular weight and standard clinical dextran in normal adult subjects resulted in a significant alteration of platelet function as characterized by marked depression of platelet factor 3 (PF 3) activity. Disruption of the abnormal platelets by sonic oscillation corrected the defect, indicating that dextran coating of the platelets inhibited the release of PF 3 activity. These findings were confirmed by in vitro studies. Infusions of serum albumin failed to produce a significant alteration in PF 3 activity. The PF 3 depression could not be related to hemodilution or the total platelet count. Clot retraction, platelet adhesiveness, and the platelet thromboplastin test were normal. Serum prothrombin time was abnormal in some subjects. The platelet abnormality was related to the plasma dextran concentration and the retention of large dextran molecules in the circulation. Clinical dextran had a more deleterious effect on PF 3 activity than low molecular weight dextran. Since the majority of subjects had normal bleeding times associated with their reduced levels of PF 3 activity, the clinical significance of these studies is not clear. Nevertheless, the results of these experiments indicate that dextran coating of platelets interferes with the release of PF 3 activity, and suggest that alteration of the platelet surface may modify other platelet functions involved in maintaining a normal bleeding time.

No abstract

No abstract

Summary Serum complement activity in newborn infants is approximately half that of normal adults and mothers at term; when related as units of complement activity per gram in globulin in the paired sera the activity is equal. The complement titers of infants with Rh hemolytic disease are significantly higher than those of normal controls. In AB hemolytic disease complement levels do not vary from the normal. The complement titer of newborns with hemolytic disease bears no constant relationship to antibody titer, bilirubin, hemoglobin or the severity of the disease process. Résumé L'activité du complément sérique chez les nouveaux‐nés est environ la moitié de celle des adultes et des mères au terme de leur grossesse; en valeur relative, cette activité, calculée par unité d'activité du complément par gramme de globuline est égale à celle des adultes. Le titre du complément chez les enfants atteints de maladie hémolytique Rhésus est nettement plus haut que celui des contrôles normaux. Dans les maladies hémolytiques A, B, O, le taux du complément ne varie pas par rapport à la normale. Le titre du complément de la maladie hémolytique Rhésus ne présente aucun rapport constant avec le titre des anticorps, le taux de bilirubine et d'hémoglobine et la gravité de l'affection. Zusammenfassung Die Komplementaktivität des Serums Neugeborener entspricht ungefähr der Hälfte derjenigen von gesunden Erwachsenen und Mütter am Geburtstermin; wird die Einheit der Komplementaktivität mit der Gewichtsmenge der in diesen Seren enthaltenen Globuline in Beziehung gebracht, ist kein Unterschied zwischen den Neugeborenen und den Erwachsenen zu bezeichnen. Die Komplementtiter sind bei Neugeborenen mit Rh Morbus haemolyticus signifikant höher als bei normalen Neugeborenen. Beim AB Morbus haemolyticus neonatorum weichen hingegen die Komplementtiter von der Norm nicht ab. Die Komplementtiter von Neugeborenen mit Morbus haemolyticus weisen keine konstante Beziehung zum Antikörpertiter, zum Bilirubin‐ und Hämoglobin‐Spiegel, sowie zum Schweregrad der Krankheit auf.