Sweet's syndrome associated with trans-retinoic acid treatment in acute promyelocytic leukaemia.

A case of acute promyelocytic leukaemia is reported in which Sweet's syndrome developed at the time of an improvement in white blood cell count due to transretinoic acid. Acute febrile neutrophilic dermatosis (Sweet's syndrome) is a disorder characterized by acute onset of inflammatory skin nodules associated with systemic features which include malaise, fever and neutrophilia. Many triggers and associated disorders have been identified since the syndrome was described, the most important being the association with haematological diseases including leukaemias and other myeloproliferative disorders. We describe a case apparently provoked by drug therapy.

Comparative serum stability of radiochelates for antibody radiopharmaceuticals.

Serum incubation of monoclonal antibodies chelate labeled by DTPA, benzyl-EDTA and benzyl-TETA with 111In, 57Co, and 67Cu demonstrated marked differences in their stability. In serum, 111In-benzyl-EDTA-antibody was more stable than 111In-DTPA-antibody. Cobalt-57 or 67Cu chelated antibody were less stable than either 111In chelated antibody; 67Cu was only firmly attached to the antibody as 67Cu-benzyl-TETA-antibody. The relative stability of the radiometal chelated antibodies was paralleled by the relative stability in serum of the radiometal chelates themselves. These in vitro studies suggest that in vivo behavior of metal chelates exposed to a complex protein environment cannot be predicted by classical equilibrium constants.

Preparation and evaluation of a hydrous tin(IV) oxide 82Sr/82Rb medical generator system for continuous elution.

Hydrous tin(IV) dioxide in the Na+-form appears to be the most efficient inorganic exchanger for a reliable and versatile clinical 82Rb generator. Continuous elution with a commercial physiological NaCl solution yields 82Rb ranging between 10 and 40% at a flow rate as low as 3 to 10 mL/min respectively. At the same time the Sr breakthrough is less than 1.6 10(-6)%/mL. A clinical generator loaded with 100 mCi 82Sr (150 mCi 85Sr) and continuously eluted for 3 min at a typical flow rate of 5 mL/min yields 40 mCi of 82Rb, 8 nCi of 82Sr and 11 nCi of 85Sr. The total absorbed radiation dose for 40 mCi 82Rb administered is primarily due to 82Rb and has been estimated for the three principal target organs as 760 mrad for the kidneys, 520 mrad for the heartwalls and 276 mrad for the lungs. The 82,85Sr contribution to the dosimetry has been shown to be negligible. The absence of radiolysis with generators loaded with high level of 82Sr was demonstrated by the excellent reproductibility of continuous elution properties of the generator during its practical shelf-life estimated to 5-6 weeks of clinical use which would require more than 30 L of eluent.

Character of transient ischemia in angina pectoris.

There is growing interest in the possible therapeutic and prognostic significance of silent myocardial ischemia in coronary artery disease (CAD) and its detection by ambulatory electrocardiographic (ECG) monitoring. In 100 apparently healthy normal subjects (20 with angiographically normal coronary arteries), Holter monitoring revealed significant ST-segment depression in only 2 (both over 40 years, one with positive treadmill test, the other with risk factor for CAD). No significant ECG changes were found in those with normal coronary vessels. In 30 patients with documented CAD, significant ST-segment depression during 1,934 episodes over 446 days of monitoring over 18 months was found. Only 24% of the episodes were associated with angina. Asymptomatic and symptomatic episodes were associated with comparable changes in perfusion detected by positron emission tomography. Heart rate increases greater than 10 beats/min preceding the onset of the ST-segment changes occurred in only 23% of the episodes. There was considerable variability in the ST-segment changes in the same patient monitored serially over long periods of time. The data indicate that it is extremely uncommon for patients without CAD to exhibit silent myocardial ischemia, whereas patients with stable angina exhibit frequent, variable and often asymptomatic ECG evidence of myocardial ischemia rarely triggered by increases in heart rate. These findings are likely to be of therapeutic and prognostic significance.

Serum stability of 67Cu chelates: comparison with 111In and 57Co.

Simple chelates and chelate conjugated monoclonal antibodies labeled with 111In, 57Co and 67Cu demonstrate marked differences in stability when exposed to a serum environment. Among these radiometals, on DTPA, the order of stability is 111In greater than 57Co much greater than 67Cu. On benzyl-EDTA, the order of stability is 111In congruent to 57Co much greater than 67Cu. Among those investigated, the only serum stable 67Cu chelate found was 67Cu-TETA. The order of stability observed for 57Co vs 67Cu is contrary to published equilibrium constants. These in vitro studies suggest that the in vivo behavior of metal chelates exposed to a complex molecular environment may not be predicted by classically determined equilibrium constants.

Transport and intracellular distribution of copper in a human hepatoblastoma cell line, HepG2.

The uptake of radiocopper by HepG2 cells is a saturable, temperature-dependent and cellular energy-independent process with a Vmax of 7.1 +/- 0.2 pmoles min-1 mg protein-1 and an estimated Km of 3.3 +/- 0.5 microM. The rate of copper uptake is reduced at an equimolar concentration of albumin and is unaffected by zinc at a 10-fold molar excess. Approximately 70% of the newly incorporated radiocopper binds to membranes and organelles, while 30% is recovered in the cytosol. The soluble fraction can be resolved into two copper-binding protein peaks. Incubation of HepG2 with nonisotopic copper results in displacement of radiocopper associated with the proteins contained in the lower molecular weight peak. Exposure of the cells to cycloheximide inhibits the incorporation of the isotope into this fraction.

Transfer of copper from metallothionein to nonmetallothionein proteins in cultured cells.

Copper uptake and distribution with time among cytoplasmic proteins were followed in cultured cells under several conditions: (1) CHO cells, which cannot synthesize metallothioneins, were labeled with(67)Cu in the presence of 100 µM ZnCl2; (2) Cd(r)30F9 cells, which contain some constitutive metallothionein (MT), were labeled in the absence of additional ZnCl2 and; (3) Cd(r)30F9 cells were labeled in the presence of ZnCl2, under which conditions they synthesized additional metallothioneins. The exogenous(67)Cu and ZnCl2, where present, were then removed, and the distributions of(67)Cu among size fractions of the cellular proteins were observed at intervals for 16 h. In addition, a culture identical to condition (3) above was also treated with 100 µM ZnCl2 during the redistribution period. The(67)Cu was initially resolved into three peaks by Sephadex G-75 chromatography: high molecular weight, intermediate molecular weight, and MT. The(67)Cu in the MT fraction decreased with at 1/2 of 10-12 h. In contrast to this, generally, in cells with a higher initial(67)Cu bound to metallothionein, there was a progressive increase in the amount of(67)Cu eluting with the high- and intermediate-molecular-weight fractions. Since no other source of(67)Cu was available, these experiments suggest that copper stored in MT can be transferred to other proteins in these cells.

A short-term assay of myeloid precursor cells in man.

An assessment of the numbers of myeloid precursor cells in human bone marrow, obtainable earlier than with conventional colony assays, would be useful for many reasons. Recently an isotopic assay for murine-colony-stimulating activity has been devised and we have modified this technique for use in man. Bone marrow mononuclear cells are incubated in microtitre plates in the presence of optimal amounts of placental-conditioned medium, pulsed with 3H-galactose for 24 h and the isotope incorporation measured. Isotope uptake by normal bone marrow was found to be proportional to both the number of cells cultured and the amount of conditioned medium added. The cells responsible for isotope incorporation have been characterized partially and found to be nonadherent immature myeloid cells and have a density of less than 1.077. This short-term isotopic assay was also compared to the GM-CFC assay in ten normals and in 24 patients with either neutropenia (of different etiology), myeloid leukemias, or neutrophil leukocytosis. There was good correlation between the two assays in all the patients studied. Thus, our observations suggest that the cell incorporating 3H-galactose in response to conditioned medium has many of the properties of the GM-CFC and its immediate progeny. Although assay specificity has yet to be proven, our early results indicate that it may have use as a rapid, but indirect, assessment of human myeloid precursor cells and thus prove to be a useful adjunct to the standard hematological methods of assessment of certain patients.

High colony stimulating activity in a patient with disseminated carcinoma and neutrophil leucocytosis.

The case of a man with widespread bronchogenic carcinoma associated with pronounced neutrophil leucocytosis is presented. There was no evidence of infection or metastatic bone marrow infiltration. Increased levels of colony stimulating activity were shown in the patient's serum using three methods. Findings in this patient suggest that the leukaemoid blood picture was related to inappropriate tumour associated production of colony stimulating factors.

Characterization of human mast cells in long-term culture.

Recent studies in rodents have demonstrated that mast cells derived from lymphoid tissues can be grown in longterm culture, provided that supportive growth factors or stromal fibroblasts are added; such findings have not been reported in man. Furthermore, although a hemopoietic origin for mast cells is supported by transplantation studies in mice, the exact origin of the human mast cell or its relationship to the circulating basophil and other hemopoietic cell lineages is unknown. We have investigated the requirements for in vitro growth of human mast cells derived from the infiltrated bone marrow of a patient with systemic mastocytosis, and have characterized both the mast cells proliferating in these cultures and those obtained from splenic infiltrates. Our data approached two questions: (1) Is there any evidence for the origin of mast cells from a bone-marrow-derived stem cell, and, if so, (2) what lineage relationship is there between mast cells and granulopoietic cells, including basophils? First, we have shown the expression of hemopoietic tissue-specific antigens by mast cells, strongly supporting a bone marrow origin for the mast cell in man (at least for those mast cells analyzed here). Second, the complete lack of granulocyte-monocyte markers contrasts with the phenotype of the basophil and suggests that mast cells diverge considerably from other granulopoietic cells during the acquisition of their differentiated specialized functions.

Granulopoiesis in the neutropenia of negroes.

A number of reports have shown that the peripheral blood neutrophil count in many negroes is considerably lower than in white populations. This neutropenia has been ascribed previously to both genetic and nutritional causes. We have studied bone marrow reserve function and myelopoiesis in 3 negroes with neutropenia, and found these to be normal.

Myocardial perfusion with rubidium-82. I. Measurement of extraction fraction and flow with external detectors.

Accurate measurement of the regional extraction of a diffusible radiopharmaceutical is essential for the quantifying of regional blood flow, and may also provide an important physiologic or diagnostic indicator of the cellular viability of an organ in man through external detection by positron emission tomography. However, extraction fraction of a diffusible tracer usually decreases as flow increases, and thus noninvasive methods for measuring flow are nonlinear unless the extraction fraction can be measured independently. This report describes the theoretical basis and documents the applicability of this theory for determining, with external detectors, the first-pass regional extraction fraction of rubidium-82 by the heart, following a single intravenous bolus injection of the tracer. Measurement of extraction fraction was found to be independent of flow, thereby making it possible to determine accurately with a single intravenous bolus injection of rubidium-82, the regional blood flow in the myocardium at up to five times normal resting flow.

Myocardial perfusion with rubidium-82. II. Effects of metabolic and pharmacologic interventions.

In order to validate a new method for quantifying coronary blood flow, we injected intravenously a bolus of rubidium-82 (Rb-82) into 28 open-chested dogs under a wide range of flow and physiologic conditions, using beta probes to monitor myocardial radioactivity. Extraction fraction and perfusion were measured using a functional model that separates the data into the free and trapped myocardial rubidium. Extraction and uptake of rubidium were lower during acidosis than during alkalosis and were unchanged by glucose-insulin, digoxin, or propranolol. Myocardial flow, as indicated by rubidium, correlated linearly with simultaneous measurements of flow by microspheres in the same sample volume over a wide range of flow (r = 0.97, n = 106, range 0.02-7.76 ml/min/g). Regional myocardial blood flow can be accurately determined using generator-produced Rb-82. Studies using current state-of-the-art, fast positron-emission tomographic cameras are required to determine the utility of this approach in man.

Further analysis of the Ly-6 genetic region: isolation and characterization of cell lines with altered expression of Ly-6 antigens.

The identity, or close linkage, or a series of murine alloantigens encoded by the Ly-6 genetic region has been well documented. We have investigated the relationship between two component antigens, Ly-6.2 and H9/25, by generating and characterizing a number of variant cell lines which have altered antigen expression, isolated by chemical mutagenesis and immunoselection of BW5147 lymphoid cells. Cloned cell lines, selected by either antiserum, show loss of both antigens and also fail to express Thy-1, a further genetically linked, but unrelated determinant. The relevance of these findings to furthering understanding of the structure of the Ly-6 region and regulation of antigen expression is discussed.

Relation between regional myocardial uptake of rubidium-82 and perfusion: absolute reduction of cation uptake in ischemia.

Experiments were undertaken using rubidium-82 and position tomography to examine the relation between myocardial perfusion and cation uptake during acute ischemia. Rubidium-82 was repeatedly eluted from a strontium-82-rubidium-82 generator. In six dogs emission tomograms were used to measure the delivered arterial and myocardial concentrations at rest and after coronary stenosis, stress and ischemia. There was a poor overall relation between regional myocardial uptake and flow measured by microspheres and a large individual variability. Extraction of rubidium-82 was inversely related to flow. Significant regional reduction of cation uptake was detected in the tomograms when regional flow decreased by more than 35 percent. This reduction was significantly greater when ischemia was present. A small but significantly greater when ischemia was present. A small but significant decrease (33.0 +/- 9.1 percent, mean +/- standard deviation) in the myocardial uptake of rubidium-82 was detected only when flow was increased by more than 120 percent in relation to a control area after administration of dypiridamole. The technique using rubidum-82 and tomography was applied in five volunteers and five patients with angina pectoris and coronary artery disease. Myocardial tomograms recorded at rest and after exercise in the volunteers showed homogeneous uptake of cation in reproducible and repeatable scans. In contrast, the patients with coronary artery disease showed an absolute mean decrease of 36 +/- 14 percent in regional myocardial uptake of rubidium-82 after exercise. These abnormalities persisted in serial tomograms for more than 20 minutes after the symptoms and electrocardiographic signs of ischemia.

Brain tumor evaluation using Rb-82 and positron emission tomography.

Positron emission tomography of the brain with 75-sec rubidium-82 obtained from a portable generator (25-day Sr-82 leads to Rb-82) was used to evaluate the integrity of the blood-brain barrier (BBB) in patients with brain tumors. Rubidium is normally excluded from the central nervous system by the intact BBB, but when the BBB is disrupted by a tumor. Rb enters and pools in the extravascular spaces of the central nervous system. Since Rb is also rapidly cleared from the blood, a high tissue-to-blood ratio of the Rb-82 tracer is achieved in regions of BBB disruption after intravenous injection. With dynamic positron emission tomographic imaging, the extravasation of the Rb tracer can be evaluated independent of the intravascular Rb concentration, and very small changes in the BBB permeability can be detected. The results of our studies in eight patients show that this technique is a promising method for evaluation of the BBB integrity in brain-tumor patients.U