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Therapeutic nuclear medicine is rapidly developing as an additional treatment modality in oncology. Its unique characteristics are the systemic, yet selective delivery of radiation doses in target tissues, its non-invasiveness, the relative lack of immediate and late side effects, and the advantage that uptake and retention in the tumor can be pre-assessed by tracer studies. Many different tumor seeking radiopharmaceuticals are being used for therapy by different routes and a variety of targeting mechanisms. The current clinical role of radionuclide therapy is briefly reviewed, as well as more general aspects and considerations, such as mechanisms for tumor targeting, the choice of radionuclide labels, radiopharmacy, drug delivery, radiation protection, dosimetry and toxicity. 相似文献
764.
Developing autoreactive B cells edit their B cell antigen receptor (BCR) in the bone marrow and are clonally deleted when they fail to reexpress an innocent BCR. Here, inducible Cre-loxP-mediated gene inversion is used to change the specificity of the BCR on mature IgM+ IgD+ B cells in vivo to address the fate of lymphocytes encountering self-antigens at this developmental stage. Expression of an autoreactive BCR on mature B cells leads to their rapid elimination from the periphery, a process that is inhibited by constitutive bcl-2 transgene expression in an antigen dose-dependent manner. Thus, selection of mature B cells into the long-lived peripheral pool does not prevent their deletion upon encounter of self-antigens. 相似文献
765.
JR Allport LE Donnelly BP Hayes S Murray NB Rendell KP Ray J MacDermot 《Canadian Metallurgical Quarterly》1996,118(5):1111-1118
1. Chemotaxis of human neutrophils is mediated by numerous agents [e.g. N-formyl-methionyl-leucyl-phenylalanine (FMLP) and platelet activating factor (PAF)] whose receptors are coupled to phospholipase C. However, the subsequent transduction pathway mediating cell movement remains obscure. We now propose involvement of mono(ADP-ribosyl)transferase activity in receptor-dependent chemotaxis. 2. Human neutrophils were isolated from whole blood and measurements were made of FMLP or PAF-dependent actin polymerization and chemotaxis. The activity of cell surface Arg-specific mono(ADP-ribosyl)transferase was also measured. Each of these activities was inhibited by vitamin K3 and similar IC50 values obtained (4.67 +/- 1.46 microM, 2.0 +/- 0.1 microM and 4.7 +/- 0.1 microM respectively). 3. There were similar close correlations between inhibition of (a) enzyme activity and (b) actin polymerization or chemotaxis by other known inhibitors of mono(ADP-ribosyl)transferase, namely vitamin K1, novobiocin, nicotinamide and the efficient pseudosubstrate, diethylamino(benzylidineamino)guanidine (DEA-BAG). 4. Intracellular Ca2+ was measured by laser scanning confocal microscopy with two fluorescent dyes (Fluo-3 and Fura-Red). Exposure of human neutrophils to FMLP or PAF was followed by transient increases in intracellular Ca2+ concentration, but the inhibitors of mono(ADP-ribosyl)transferase listed above had no effect on the magnitude of the response. 5. A panel of selective inhibitors of protein kinase C, tyrosine kinase, protein kinases A and G or phosphatases 1 and 2A showed no consistent inhibition of FMLP-dependent polymerization of actin. 6. We conclude that eukaryotic Arg-specific mono(ADP-ribosyl)transferase activity may be implicated in the transduction pathway mediating chemotaxis of human neutrophils, with involvement in the assembly of actin-containing cytoskeletal microfilaments. 相似文献
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A breeding place of immature stages of Aedes albopictus in bromeliads is described. The epidemiological role of bromeliaceae as natural or artificial containers, is discussed. The ability of the mosquito to expand its habitat calls for attention especially as regards its adaptability as an invading species. 相似文献
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KP Ebmeier DH Blackwood C Murray V Souza M Walker N Dougall AP Moffoot RE O'Carroll GM Goodwin 《Canadian Metallurgical Quarterly》1993,33(7):487-495
We examined 20 actively psychotic unmedicated schizophrenic patients and 20 matched control subjects by using single-photon emission, computed tomography (SPECT) with 99mtechnetium-exametazime. Patients showed a hyperfrontal pattern of tracer uptake with significant relative increases in superior prefrontal cortex. This abnormality was less pronounced in patients with higher symptom scores for psychomotor poverty. In addition, patients showed associations between certain schizophrenic syndrome scores, such as psychomotor poverty, disorganization, and reality distortion, and tracer uptake to a number of cortical and subcortical brain regions. This syndrome-related pattern of tracer uptake was, at least in part, consistent with similar associations previously reported in chronically medicated schizophrenic patients. SPECT therefore provides a readily available method to examine the relationship between symptom pattern and regional brain metabolism in psychotic patients. Any observed patterns of association will depend on the current mental and medication status of the patients examined. 相似文献