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Aim: Rapid detection of biological agents in biodefense is critical for operational, tactical and strategic levels as well as for medical countermeasures. Yersinia pestis, Francisella tularensis, and Bacillus anthracis are high priority agents of biological warfare or bioterrorism and many response forces use lateral flow assays (LFAs) for their detection. Several companies produce these assays, which offer results in short time and are easy to use. Despite their importance, only few publications on the limits of detection (LOD) for LFAs are available. Most of these studies used inactivated bacteria or risk group‐2 strains. As the inactivation process in previous studies might have affected the tests' performances, it was our aim in this study to determine and compare the LOD of several commercially available LFAs using viable risk group‐3 strains. Methods and Results: Lateral flow assays from four different companies for the detection of following bacteria were evaluated: Y. pestis, F. tularensis and B. anthracis spores. Two independent quantification methods for each target organism were applied, in order to ensure high quantification accuracy. LODs varied greatly between tests and organisms and ranged between 104 for Y. pestis‐tests and as high as >109 for one B. anthracis‐test. Conclusion: This work precisely determined the LODs of LFAs from four commercial suppliers. The herein determined LODs differed from results of previous studies. This illustrates the need for using accurately quantified viable risk group 3‐strains for determining such LODs. Significance and Impact of the Study: Our work bridges an important knowledge gap with regard to LFA LOD. The LODs determined in this study will facilitate better assessment of LFA‐results. They illustrate that a negative LFA result is not suited to exclude the presence of the respective agent in the analyzed sample. [ABSTRACT FROM AUTHOR]

Bispecific antibodies (bsAb) are considered as promising tools for the elimination of disseminated tumour cells in a minimal residual disease situation. The bsAb-mediated recruitment of an immune effector cell in close vicinity of a tumour cell is thought to induce an antitumoural immune response. However, classical bispecific molecules activate only a single class of immune effector cell that may not yield optimal immune responses. We therefore constructed an intact bispecific antibody, BiUII (anti-CD3 × anti-EpCAM), that not only recognizes tumour cells and T lymphocytes with its two binding arms, but also binds and activates Fcγ-receptor positive accessory cells through its Fc-region. We have demonstrated recently that activated accessory cells contribute to the bsAb-induced antitumoural activity. We now analyse this stimulation in more detail and demonstrate here the BiUll-induced upregulation of activation markers like CD83 and CD95 on accessory cells and the induction of neopterin and biopterin synthesis. Experiments with pure cell subpopulations revealed binding of BiUll to CD64+ accessory cells and CD16+ NK cells, but not to CD32+ B lymphocytes. We provide further evidence for the importance of the Fc-region in that this bispecific molecule stimulates Fcγ-R-positive accessory cells to eliminate tumour cells in vitro by direct phagocytosis. [ABSTRACT FROM AUTHOR]

Bone marrow aplasia was induced by fractionated whole body irradiation with 3000 R and restitution was started by autologous bone marrow transplantation. During the period of aplasia the amount of buffy coat biopterin clearly followed the decline of leukocytes and, vice versa, during reconstitution it largely paralleled their increase in number. The amount of red cell biopterin closely correlated with the number of reticulocytes rather than with the fairly constant values for hematocrit or of erythrocytic protein. Thereby it clearly followed the various periods of red cell recovery. The amount of cellular biopterin, its concentration with respect to cell number or to unit of protein and the percentage distribution of biopterin among the cell fractions are presented as characteristics of the activity of hemopoietic cell proliferation. [ABSTRACT FROM AUTHOR]

Using the Crithidia assay 3.0 ng biopterin/ml blood was found, of which one third was present in the plasma. The erythrocyte fraction comprised 1.7 ng and the buffy coat 0.33 ng. After Ficoll separation 0.050 ng were found in the lymphocyte layer of 1 ml blood. During blast crisis of chronic myelocytic leukemias increased amounts of biopterin were found in the erythrocyte fraction and in the buffy coat. The high biopterin concentration per unit of protein in the white cell fraction indicated the presence of blasts. In Polycythemia vera increased amounts of biopterin in both the red cell fraction and in the buffy coat were also found but the percentage distribution within total cellular biopterin was markedly shifted toward the erythrocyte fraction. In cases of chronic and acute lymphocytic leukemias the low amounts of biopterin in the red cell fraction agreed with the current view of partial extinction of the erythropoietic line. The isolated lymphoblasts were characterized by high biopterin concentrations per unit of protein. During remission the biopterin patterns approached normal levels. [ABSTRACT FROM AUTHOR]

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Irradiation of fully developed green leaves as well as irradiation of isolated chloroplasts causes a rapid, reversible increase in the activity of NADP-linked phosphoglyceraldehyde dehydrogenase. This increase is closely connected with the functioning of the non-cyclic electron flow of photosynthesis. It is accompanied by a decrease in the activity of the NAD-linked enzyme. The experiments presented here show that it is not the kinase but the dehydrogenase which is the rate limiting factor in the over-all reaction measured up to date. The activation of the ‘dark-enzyme’ (= basic enzyme) resulting in the ‘light-enzyme’ (= activated enzyme) is not due to an unspecific reduction of S-S-groups in the reactive center. Dithiothreitol only restores the activity lost during the isolation procedure of the chloroplasts. NADPH rather than dithiothreitol causes a specific activation of the basic enzyme. How- ever the basic enzyme must be present in the completely reduced form to undergo maximal activation. Incubation with dithiothreitol and NADPH thus results in an activation rate as high as that caused by light in vivo. Activation of the NADP-linked dehydrogenase could also be attained by NADPH after its partial purification by ammonium sulfate fractionation. The activation rate by incubation with different concentrations of NADPH shows a sigmoidal type of curve. There are characteristic differences in sensitivity between the activity of the basic enzyme and its ability to be activated at different temperatures between 52°–60°. The results indicate that the action of NADPH may be an anosteric one, causing a transition from a NAD- (or possibly a NAD + NADP)-dependent to a NADP-dependent form of the enzyme. A diagram for a feed-forward activation of the NADP-linked dehydrogenase which possibly takes part in regulation of C02-fixation is presented. [ABSTRACT FROM AUTHOR]