Familial essential thrombocythemia.

Primary or essential thrombocythemia is rarely observed in childhood, and familial occurrence has been reported only once. In this study, essential thrombocythemia is documented in five members of both sexes from two to 62 years of age in three successive generations. The propositus had a persistent elevation of the platelet count, splenomegaly, a normal hemoglobin level, a normal white blood cell count, and abnormal platelet aggregation. Platelet arachidonic acid metabolites assayed by high-performance liquid chromatography and serum thrombopoietin levels were normal. Megakaryocytes were increased in number and size. Both mature and early immature megakaryocytes, but no atypical megakaryocytes, were identified by surface immunofluorescence. Bone marrow cultures showed normal myeloid and erythroid colony formation, and chromosome studies revealed a normal female karyotype. These findings support the concept that familial essential thrombocythemia is a myeloproliferative disorder that is transmitted by an autosomal dominant mode of inheritance, and that untreated young women and children with essential thrombocythemia have long survival.

Liposome-encapsulated gentamicin treatment of Mycobacterium avium-Mycobacterium intracellulare complex bacteremia in AIDS patients.

TLC G-65, a liposome-encapsulated gentamicin, was given intravenously twice weekly for 4 weeks to AIDS patients with Mycobacterium avium-M. intracellulare complex (MAC) bacteremia at 1.7 mg of gentamicin per kg of body weight per infusion (4 patients), 3.4 mg/kg (10 patients), and 5.1 mg/kg (7 patients). MAC colony counts in blood fell by 75% or more in all three groups (P < 0.005). Drug resistance did not emerge during the study period. Transient renal insufficiency developed in one patient; no other adverse effects were detected. Liposome-encapsulated gentamicin is a potential therapy for MAC infections in AIDS patients.

A phase I escalating-dose safety, dosimetry and efficacy study of radiolabeled monoclonal antibody LYM-1.

Thirteen patients with relapsed or refractory Non-Hodgkin's Lymphoma were treated with 131I-Lym-1 during the course of a dose escalation trial. Principal aims were to establish the maximum tolerated single dose (MTD), as well as to assess clinical and dosimetric effects of the MTD. Patients were eligible if > 25% of tumor cells bound Lym-1 on immunohistochemistry, stain intensity was +2/4 or greater and human anti-mouse antibody (HAMA) assay was negative. Radioimmunotherapy was performed with escalating doses at levels of 50 mCi, 65 mCi/m2 and 80 mCi/m2 (50-139 mCi total). Patients were eligible for retreatment after 6-10 weeks if there was no severe toxicity, their disease was at least stable and HAMA remained negative. Three were retreated. Four have achieved partial responses which lasted 11, 11, 18 and 22 weeks. Acute toxicities included rigors (69%), fever (62%), nausea (46%), vomiting (46%), pruritus (23%), urticaria (23%), chest pain (23%) and bronchospasm (15%). HAMA developed in 3 patients. Myelosuppression, manifested as thrombocytopenia and neutropenia, was dose-limiting and defined the single dose MTD at 65 mCi/m2. Plasma radioactivity clearance was biphasic, with a 0.9 hr alpha-T1/2 and a 19.8 hr beta-T1/2. At completion of Lym-1 infusion, a mean of 45% of the injected dose was recoverable in the circulation. Images obtained within the first 2 hours indicated mean hepatic and splenic uptake was 29% and 11%, respectively. Radiation absorbed doses to tumor ranged from 18-61 rads; mean doses to whole body ranged from 17 to 71 rads.