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SummaryA Japanese boy, who had combined congenital defects - a hemorrhagic disorder due to abnormal platelet function and incomplete albinism, was described. His parents were first cousins. Platelet aggregation by collagen and epinephrine was markedly defective. A rapid disaggregation was observed in ADP-induced aggregation. Platelet factor 3 availability and in vitro adhesiveness were subnormal, while platelet factor 3 activity was normal. Defective ADP release was associated with impaired aggregation by collagen. Before aggregation, labeled adenine nucleotide pattern in patient’s platelets was not different from that in normal platelets. The increase of intermediates of platelet ATP breakdown, such as AMP and IMP, was less in patient’s platelets after collagen-induced aggregation. The release of labeled ATP and ADP in patient’s plasma was less than that in normal plasma.

Three cases of thrombocytopathic purpura with partial platelet dysfunction are reported. The platelets were defective in clot retraction, but normal in prothrombin conversion.

SummaryCharacteristic electrophoretic patterns have been observed in all 5 cases of hemophilia and in all 8 cases of idiopathic thrombocytopenic purpura. These patterns show the following characteristics: (a) appearance of an unusual peak in the group of the α-globulins (αx), and (b) disappearance of the usual α2- and α3-globulin peaks. The same anomaly has been observed in some cases of secondary thrombocytopenia, “anaphylactoid” type of vascular purpura, and hemolytic anemia with evidence of platelet dysfunction.

A spectrum or continuum of conditions including hemophilia and von Willebrand's disease is illustrated by reports from the literature and patients seen at the University of Minnesota over a four year period. These included inherited disorders with low levels of factors VIII and/or IX and/or platelet dysfunction of the von Willebrand type. These disorders form an extremely heterogeneous group. The individual patient should be simply classified insofar as possible on functional, biochemical, and therapeutic bases. New name classifications for each variant should be avoided.

Although platelet defects have been documented in newborn (NB) infants, the mechanism of this abnormality is not clear. In this study we have obtained data showing adenosine diphosphate (ADP) release in NB platelets is impaired because of a lack of sensitivity to external stimuli. % aggregation to strong collagen (SC), weak collagen (WC), and epinephrine (E) was less in NB platelet-rich plasma than paired maternal (M) samples (57 ± 5% vs. 74 ± 4%, p 0.4). Whereas M responded equally well to WC; NB did not (p

To the Editor.— It is encouraging to note that my observation 1 of 1966 that aspirin increased the bleeding time and my efforts to alert the medical profession to its potential danger, especially in bleeders, 2 are slowly gaining recognition and support. Particularly interesting is the report ( 213: 2049, 1970) on "Studies on the Detection of Adverse Drug Reactions in the Newborn: I. The Effects of Prenatal Aspirin on Newborn Hemostasis." Unfortunately, the adverse effects observed clinically are explained by a unilateral approach based on the uncritical concept that defective hemostasis is primarily brought about by either a platelet or a coagulation defect, and then neglecting to study either adequately. The prothrombin consumption time test was not employed and, yet, without this test, neither coagulation nor platelet dysfunction can be accurately evaluated. The bleeding time, which is one of the few reliable procedures for studying the vascular response in hemostasis

Excerpt The modified template Ivy bleeding time was evaluated as a test of in vivo platelet function in 79 selected patients with acquired and genetic platelet dysfunction. The bleeding time in 100...