Sensitivity and nonspecific staining of various immunoperoxidase techniques

Summary Optimally fixed paraffin embedded tissue sections and cytocentrifuged cell smears were used to test the sensitivity and nonspecific staining with the enzyme-bridge, PAP, indirect and direct immunoperoxidase methods using human immunoglobulins and lysozyme as antigens. With the enzyme-bridge method positive staining was seen with primary antiserum dilutions up to 1:20,000. The least background staining was observed with this method. The PAP method was equally sensitive, although false-negative results with low primary antiserum dilutions were seen. Some nonspecific background staining always persisted using the PAP method even with high primary antiserum dilutions. The indirect method was not as sensitive as the enzyme-bridge method and some nonspecific staining always persisted. The direct method was too insensitive with paraffin embedded tissue sections.Supported by the Sigrid Jusélius Foundation and Finska Läkaresällskapet     

Metal trafficking: from maintaining the metal homeostasis to future drug design

The diverse proteins and enzymes involved in metal trafficking between and inside human cells form numerous transport networks which are highly specific for each essential metal ion and apoprotein. Individual players include voltage-gated ion channels, import and export proteins, intracellular metal-ion sensors, storage proteins and chaperones. In the case of calcium, iron and copper, some of the most apparent trafficking avenues are now well established in eukaryotes, while others are just emerging (e.g. for zinc, manganese and molybdenum). Chemistry provides an important contribution to many issues surrounding these transport pathways, from metal binding-constants and ion specificity to metal-ion exchange kinetics. Ultimately, a better understanding of these processes opens up opportunities for metal-ion-related therapy, which goes beyond traditional chelate-based metal ion detoxification.     

Production and validation of the pharmacokinetics of a single-chain Fv fragment of the MGR6 antibody for targeting of tumors expressing HER-2

The HER-2 antigen, which is overexpressed in many breast carcinomas, is an ideal target for monoclonal antibodies due to its low expression in normal tissue and its homogeneous distribution in the tumor mass. We have developed and characterized the murine MAb MGR6 against HER-2, which is able to inhibit proliferation of tumor cells overexpressing HER-2. On the basis of these preclinical results, phase I studies in breast carcinoma patients were conducted and radiolocalization data indicated an antibody half life which directly paralleled that of other whole antibodies and thus resulting in a limited in vivo diagnostic capacity. To obtain a smaller reagent with possibly improved in vivo properties, a single chain variable fragment (scFv) of the original MGR6-producing hybridoma was generated by phage display technology. Biologically active MGR6 scFv was purified rapidly and at high yield by metal affinity chromatography. Competition FACS and ELISA analyses identified an epitope on the HER-2 extracellular domain that was shared by the scFv and the parental MAb. BIAcore analysis indicated a K_off of 9.3 × 10⁻⁴ s⁻¹, similar to that of the intact MGR6 MAb. Distribution and elimination half-lives of MGR6 scFv, calculated from in vivo preclinical evaluations, were much faster (13 min and 6.2 h, respectively) than previously published results for the intact MAb (mean t1/2β of 46 h). This represents a theoretical improvement in pharmacokinetics with respect to the parental murine MAb and points to the potential for utilizing this fragment in redirecting therapeutic agents, such as radioisotopes, to different human carcinomas overexpressing HER-2. Received: 10 August 2000 / Accepted: 19 October 2000     

Blockade of receptor for advanced glycation endproducts: a new target for therapeutic intervention in diabetic complications and inflammatory disorders

The glycation and oxidation of proteins/lipids leads to the generation of a new class of biologically active moieties, the advanced glycation endproducts (AGEs). Recent studies have elucidated that carboxymethyllysine (CML) adducts of proteins/lipids are a highly prevalent AGE in vivo. CML-modified adducts are signal transduction ligands of the receptor for AGE (RAGE), a member of the immunoglobulin superfamily. Importantly, CML-modified adducts accumulate in diverse settings. In addition to enhanced formation in settings of high glucose, these adducts form in inflammatory milieu. Studies performed both in vitro and in vivo have suggested that the proinflammatory/tissue destructive consequences of RAGE activation in the diabetic/inflamed environment may be markedly attenuated by blockade of the ligand-RAGE axis. Here, we will summarize the known consequences of RAGE activation in the tissues and highlight novel areas for therapeutic intervention in these disease states.     

Decomposition and nitrogen dynamics of wheat residues and impact on wheat growth stages

N mineralisation and immobilisation were quantified in field conditions in the presence or in the absence of wheat residues. The incubation study was conducted in cylinders placed in microplots (no plants were grown in cylinders), and the rest of each microplot was sowed with the wheat crop (Triticum durum var. Massa). N mineralisation and immobilisation depend on the presence or the absence of wheat residues. In absence of residues, a linear model of regression was developed to follow the clear nitrogen mineralisation at different soil levels. Nitrogen mineralisation (mg kg-1), during the five months of wheat development, showed the following decreasing order: 0-15 cm (132.6) > 15-30 cm (120.6) > 30-45 cm (91.3). The mineralisation rate was 24.1, 22.9 and 18.9 mg kg-1 d-1 for 0-15, 15-30 and 30-45 cm levels, respectively. The supply of wheat residues resulted in a five months N immobilisation process. At level 0-15 cm the immobilisation (mg kg-1) showed the following decreasing order: (61.6) > (46.4) > (30.0) for the supply of wheat residues at seeding time, and 15 and 30 d before seeding respectively. At the other levels, the same decreasing order was recorded. The supply of 8 t ha-1 of wheat residues at seeding time, and 15 or 30 d before seeding, decreased the dry matter yield and N accumulation in wheat crop. In consequence, there was no synchronism between the nitrogen liberated by wheat residues decomposition and the wheat growth.     

Cutting edge: identification of novel T cell epitopes in Lol p5a by computational prediction.

Although atopic allergy affects 相似文献   

Where did the finch go? Insights from radio telemetry of the medium ground finch (Geospiza fortis)

Movement patterns and habitat selection of animals have important implications for ecology and evolution. Darwin''s finches are a classic model system for ecological and evolutionary studies, yet their spatial ecology remains poorly studied. We tagged and radio‐tracked five (three females, two males) medium ground finches (Geospiza fortis) to examine the feasibility of telemetry for understanding their movement and habitat use. Based on 143 locations collected during a 3‐week period, we analyzed for the first time home‐range size and habitat selection patterns of finches at El Garrapatero, an arid coastal ecosystem on Santa Cruz Island (Galápagos). The average 95% home range and 50% core area for G. fortis in the breeding season was 20.54 ha ± 4.04 ha SE and 4.03 ha ± 1.11 ha SE, respectively. For most of the finches, their home range covered a diverse set of habitats. Three finches positively selected the dry‐forest habitat, while the other habitats seemed to be either negatively selected or simply neglected by the finches. In addition, we noted a communal roosting behavior in an area close to the ocean, where the vegetation is greener and denser than the more inland dry‐forest vegetation. We show that telemetry on Darwin''s finches provides valuable data to understand the movement ecology of the species. Based on our results, we propose a series of questions about the ecology and evolution of Darwin''s finches that can be addressed using telemetry.