Isolation of functionally different human monocytes by counterflow centrifugation elutriation

Human peripheral blood monocytes were isolated by counterflow centrifugation elutriation (CCE). This technique was modified in such a way that various monocyte fractions (viability greater than 99%) could be elutriated by increasing the density of the CCE-medium in steps of 0.0027 g/ml. All monocytes showed the same size distributions as determined by electronic sizing, which indicated that they differed in their density only. Both cytoplasmic esterase and peroxidase activity increased with the density of the cells. Furthermore, the monocytes with the highest density were 2.3-4 times more active in an antibody- dependent cellular cytotoxicity (ADCC) assay than those with the lowest density. In contrast, the monocyte with the highest density were less capable to induce the proliferation of lymphocytes in mixed leukocyte cultures (MLC) than those with the lowest density. This observation could not be attributed to differences in the expression of HLA-DR determinants, since a monoclonal antibody directed against HLA-DR antigens reacted equally well with the monocytes in different fractions. These results provide evidence for the existence of functionally different subsets of monocytes or different states of differentiation or maturation.     

Defective delivery of iron to the developing red cell of the Belgrade laboratory rat

Erythroid cell iron and transferrin uptake and release was studied in the anemia of the Belgrade laboratory rat (gene symbol, b), an autosomal recessive trait characterized by hypochromia and hyperferrinemia. When reticulocyte-rich red cells were incubated in vitro with doubly (59Fe, 125I) labeled transferrin, b/b cells demonstrated a significantly higher uptake of transferrin (164% of control at 60 min), and a significantly lower uptake of iron (21% of control at 60 min) than control cells. These findings with b/b cells were simulated by sodium-fluoride-treated control cells, but not by trypsin-treated control cells. When reticulocytes exposed to doubly labeled transferrin were incubated in normal rat plasma, there was a substantial loss of 125I from both the b/b cells (mean 71%) and control cells (mean 49%), but only a loss of 59Fe from the b/b cells (mean 21%). These findings suggest a defect in the delivery of iron to the b/b reticulocyte, which is distal to the binding of transferrin to its cell surface receptor.     

Use of medical radiographs: extent of variation and associated active bone marrow doses

An analysis of radiologic practice in five areas of Maine was undertaken for three purposes: to identify those radiologic examinations associated with the highest variation in use so that guidelines can be instituted to correct for excess use; to identify the major contributors to absorbed dose to the active bone marrow; and to estimate annual and cumulative dose to the active bone marrow as a function of age. Our data indicate that variation in radiologic use is no larger, on average, than is variation in the use of surgical procedures and that the largest variations are found in mammograms and films of the skull and lumbar spine. For all patient age groups, four types of examinations contribute 75%-85% of the annual dose to the active bone marrow: examinations of the stomach and intestines using barium contrast material, intravenous urograms, studies of the biliary tract, and lumbar spine films. Over 80% of the total dose to the active bone marrow from diagnostic radiology in patients occurs after age 40 and nearly 60% after age 55; this suggests that the potential number of induced leukemias from diagnostic radiology may be lower than previously estimated.     

Assessment of regional wall motion and perfusion by multigated myocardial scintigraphy after intracoronary Tl-201

Fourteen patients undergoing intracoronary thrombolysis for acute myocardial infarction had intracoronary injection of thallium-201 to assess myocardial salvage after reperfusion. Scintigrams of the perfused myocardium were gated and compared with both ungated scans and radionuclide ventriculograms (multigated blood pool scintigrams) to determine the value of gated perfusion images for studies of both perfusion and regional wall motion. Multigated and ungated thallium images provided comparable information about regional myocardial perfusion. Correlation between multigated thallium images of regional wall motion and radionuclide ventriculograms was poor (tau = 0.44). Assessment of wall motion was most accurate in well-perfused segments and least accurate in partially perfused segments.     

Bone marrow transplantation for the treatment of acute nonlymphoblastic leukemia in children aged less than 2 years

Eleven children with acute nonlymphoblastic leukemia in first remission who were less than 2 years of age at diagnosis were treated with 120 mg/kg of cyclophosphamide, 12-Gy fractionated total-body irradiation, and marrow transplantation. Seven patients remain in complete remission from 3.5 to 13.8 years posttransplant, four for more than 6.75 years. The immediate posttransplant course was relatively uncomplicated in surviving patients. No child developed severe graft-v-host disease. The major long-term side effect has been a slowing in growth. Although the prognosis for such children with conventional chemotherapy remains poor, intensive cytotoxic therapy and marrow transplantation offers an alternative therapy with a chance for cure.     

Detection of eastern equine encephalomyelitis virus and Highlands J virus antigens within mosquito pools by enzyme immunoassay (EIA). II. Retrospective field test of the EIA

Enzyme immunoassays (EIAs) for eastern equine encephalomyelitis (EEE) and Highlands J (HJ) virus antigens were compared in a retrospective study with standard virus isolation procedures (VIP) for detection of alpha virus-infected mosquito pools. The original VIP was a plaque assay in chick embryo cell culture, and was performed in the years from 1979 to 1981. Using the original VIP as the reference standard, the sensitivity rate of the EIA was 0.7674 and the false negative rate was 0.2326. However, when the storage age and the initial virus titer of the sample were considered, the sensitivity rate increased. For samples containing greater than 1,500 plaque-forming units (PFU) per ml of virus during the original VIP, the sensitivity rate of the EIA was 0.97; but the rate declined to 0.14 for those originally containing less than 500 PFU per ml. Most of the false negatives (68%) occurred with samples containing less than 500 PFU per ml. Presumably the low quantities of virus in these 50 pools were lost during storage and handling; virus was obtained from only 16% (8/50) during reisolation attempts using BHK-21 cells. Specificity of the EIA was excellent; no false positive results were obtained and serological identification was identical to that determined by plaque reduction neutralization in greater than 98% of the pools examined. Characteristics of the pools, such as pool size, species of mosquitoes, or gravidity did not affect the EIA results. These studies support the use of EIAs in surveillance programs attempting to determine infection rates of known arboviruses in vector populations.