Failure to confirm XMRV/MLVs in the blood of patients with chronic fatigue syndrome: a multi-laboratory study

Murine leukemia viruses (MLVs), including xenotropic-MLV-related virus (XMRV), have been controversially linked to chronic fatigue syndrome (CFS). To explore this issue in greater depth, we compiled coded replicate samples of blood from 15 subjects previously reported to be XMRV/MLV-positive (14 with CFS) and from 15 healthy donors previously determined to be negative for the viruses. These samples were distributed in a blinded fashion to nine laboratories, which performed assays designed to detect XMRV/MLV nucleic acid, virus replication, and antibody. Only two laboratories reported evidence of XMRV/MLVs; however, replicate sample results showed disagreement, and reactivity was similar among CFS subjects and negative controls. These results indicate that current assays do not reproducibly detect XMRV/MLV in blood samples and that blood donor screening is not warranted.     

Sustainable agriculture and free market economics: Finding common ground in Adam Smith

There are two competing approaches to sustainability in agriculture. One stresses a strict economic approach in which market forces should guide the activities of agricultural producers. The other advocates the need to balance economic with environmental and social objectives, even to the point of reducing profitability. The writings of the eighteenth century moral philosopher Adam Smith could bridge the debate. Smith certainly promoted profit-seeking, private property, and free market exchange consistent with the strict economic perspective. However, his writings are also consistent with many aspects of sustainable agriculture. For example, Smith argued that people ought to exercise restraint in their pursuit of self-interest, and he believed in balancing economic with environmental and social considerations. If both sides of the debate more fully regard the work of Adam Smith, then proponents of the strict economic perspective might be more appreciative of the concerns raised within the sustainable agriculture community, while advocates of sustainability might be more effective in achieving the objective of a sustainable agriculture. Harvey S. James Jr., PhD is an Associate Professor in the Division of Applied Social Sciences at the University of Missouri-Columbia. His research interests are in the economic determinants of trust and ethical behavior. He recently completed studies on trust in biotechnology institutions and the ethical attitudes of farmers.     

Scanning Single-Electron Transistor Microscopy: Imaging Individual Charges

A single-electron transistor scanning electrometer (SETSE)-a scanned probe microscope capable of mapping static electric fields and charges with 100-nanometer spatial resolution and a charge sensitivity of a small fraction of an electron-has been developed. The active sensing element of the SETSE, a single-electron transistor fabricated at the end of a sharp glass tip, is scanned in close proximity across the sample surface. Images of the surface electric fields of a GaAs/AlxGa1-xAs heterostructure sample show individual photo-ionized charge sites and fluctuations in the dopant and surface-charge distribution on a length scale of 100 nanometers. The SETSE has been used to image and measure depleted regions, local capacitance, band bending, and contact potentials at submicrometer length scales on the surface of this semiconductor sample.     

A Relationship between Photoperiod and Cold-Storage Treatment in the Spruce Budworm

Exposure of diapausing second-instar larvae of Choristoneura fumiferana to continuous light at 21 degrees C, after only 6 weeks' storage at 0 degrees C, induces emergence of larvae that will not emerge in photoperiods of 15 or 18 hours. Following the normal storage period (20 weeks) there is no such effect. Complete dark or 12-hour photoperiods inhibit emergence after storage periods of all lengths.     

Heat inhibition of tuber development in potato (Solanum tuberosum L.): effects on microtuber formation in vitro

Summary Microtuber formation by single node stem segments of in vitro grown potato plantlets was used as a model system for investigation of heat inhibition of tuber development. The stem segments were incubated in darkness at 20°C or 26°C on a tuberisation medium containing benzyl aminopurine (140 μg 1⁻¹) and sucrose (80 g 1⁻¹). Continuous incubation at 26°C strongly inhibited tuberisation and exposure to 26°C for only 1 week before transfer to 20°C significantly reduced microtuber fresh weight. Inclusion of a gibberellin synthesis inhibitor, paclobutrazol (10⁻⁵ M), in the tuberisation medium counteracted the heat inhibition of tuber initiation but not the reduction of microtuber fresh weight. Thus, consistent with previous reports, inhibition of tuber initiation appears attributable to increased endogenous levels of gibberellins. Possible causes of the reduction in microtuber fresh weight are discussed.     

Hematology of healthy Florida manatees (Trichechus manatus)

Background: Hematologic analysis is an important tool in evaluating the general health status of free‐ranging manatees and in the diagnosis and monitoring of rehabilitating animals. Objectives: The purpose of this study was to evaluate diagnostically important hematologic analytes in healthy manatees (Trichechus manatus) and to assess variations with respect to location (free ranging vs captive), age class (small calves, large calves, subadults, and adults), and gender. Methods: Blood was collected from 55 free‐ranging and 63 captive healthy manatees. Most analytes were measured using a CELL‐DYN 3500R; automated reticulocytes were measured with an ADVIA 120. Standard manual methods were used for differential leukocyte counts, reticulocyte and Heinz body counts, and plasma protein and fibrinogen concentrations. Results: Rouleaux, slight polychromasia, stomatocytosis, and low numbers of schistocytes and nucleated RBCs (NRBCs) were seen often in stained blood films. Manual reticulocyte counts were higher than automated reticulocyte counts. Heinz bodies were present in erythrocytes of most manatees. Compared with free‐ranging manatees, captive animals had slightly lower MCV, MCH, and eosinophil counts and slightly higher heterophil and NRBC counts, and fibrinogen concentration. Total leukocyte, heterophil, and monocyte counts tended to be lower in adults than in younger animals. Small calves tended to have higher reticulocyte counts and NRBC counts than older animals. Conclusions: Hematologic findings were generally similar between captive and free‐ranging manatees. Higher manual reticulocyte counts suggest the ADVIA detects only reticulocytes containing large amounts of RNA. Higher reticulocyte and NRBC counts in young calves probably reflect an increased rate of erythropoiesis compared with older animals.