Autoimmune hemolytic anemia associated with anti-Sc1

A case of autoimmune hemolytic anemia (AIHA) in a young child is described. The hemolysis was resistant to steroid therapy but responded to splenectomy and intravenous immunoglobulin. The autoantibody was shown to be anti-Sc1 by both serologic and immunoblotting techniques. This seems to be the first report of an autoanti-Sc1 detected by immunoblotting and the first example of AIHA in a child caused by autoanti-Sc1.     

Noninfiltrating angiolipoma of the mediastinum

A case of mediastinal angiolipoma in a 63-year-old man is described. A computed tomographic scan of the thorax demonstrated a large encapsulated mass with fatty and soft-tissue components near the esophagus. This appearance was considered suggestive of a liposarcoma. However, at surgery a benign noninfiltrating angiolipoma was found and removed. To the authors' knowledge, angiolipomas have not previously been reported to occur within the mediastinum.     

Influence of diuretics on brachial artery diameter and distensibility in hypertensive patients

Blood pressure, brachial artery diameter and pulse wave velocity were determined before and after diuretic treatment in 2 groups of hypertensive patients treated either by indapamide (2.5 mg per d) or by canreonate (50 mg per d). Brachial artery diameter, measured from pulsed Doppler flowmetry, and pulse wave velocity, evaluated from mechanography, did not alter significantly despite a significant blood pressure reduction. The study indicates that, in hypertensive patients of middle age, diuretics did not change brachial artery diameter and distensibility, whether the drug caused an increase or a decrease in plasma potassium levels.     

Identification of functional domains on von Willebrand factor by binding of tryptic fragments to collagen and to platelets in the presence of ristocetin

With the use of monoclonal antibodies that inhibit the ristocetin- induced binding of von Willebrand factor (VWF) to platelets and the binding to collagen, we have previously identified two distinct tryptic fragments. To prove that these fragments contain the platelet binding or the collagen binding domain, we investigated the direct binding of tryptic fragments of 125I-VWF to platelets in the presence of ristocetin and to collagen fibrils. During the course of the tryptic digestion, there was a rapid and parallel decrease in binding to platelets and collagen. In the first ten minutes, binding decreased greater than 50%; a further decrease to 19% and 29%, respectively, was noted at 90 minutes, but no further decrease was observed thereafter. The bound fragments were eluted from platelets and collagen and analyzed on polyacrylamide gradient gels. The fragments bound to the platelets appeared to be reduced, probably by endogenous reducing substances from the platelets. This was prevented by addition of N- ethylmaleimide during the incubation. After 24 hours of digestion, platelets predominantly bound fragments of 116 kd and collagen bound a single fragment of 48 kd. These fragments are similar to those previously identified with the monoclonal antibodies.     

Childhood Ki-1 lymphoma presenting with skin lesions and peripheral lymphadenopathy

We describe a large-cell lymphoma of activated lymphoid cells in six children and adolescents. The presenting clinical features of regressing skin lesions and peripheral lymphadenopathy, sinus infiltration of lymph nodes, and infrequent tumor cell erythrophagocytosis resulted in initial diagnoses of malignant or regressing atypical histiocytosis in five cases. Binucleate and multinucleate tumor cells, sometimes with prominent eosinophilic nucleoli, resembled Reed-Sternberg (RS) cells and occasionally were found in a cytoarchitectural milieu that was consistent with a diagnosis of Hodgkin's disease (HD). The tumor cells did in fact express the HD-associated antigen Ki-1, but unlike most types of HD, the RS-like cells expressed common leukocyte antigen and were negative for Leu-M1. A T cell origin for the malignant cells was demonstrated with monoclonal antibodies in two cases, by focal staining for nonspecific esterase in one case, and by rearrangement of the beta- chain genes for the T cell receptor in a fourth case. These studies provide further evidence that some cases previously interpreted as malignant or regressing atypical histiocytosis and some types of HD are actually T cell disorders.