Selective disruption of oncogenic RET signaling in medullary thyroid carcinoma in vitro and in vivo is associated with loss of the neoplastic phenotype of medullary thyroid carcinoma and should be investigated further as the basis for new therapeutic approaches for this disease.

Mutant hepatitis B virus with substitutions within the coding region for HBV surface antigen (HBsAg) has been found naturally in chronic carriers. It is therefore important to clarify whether the identified substitutions within the HBsAg have impact on the antigenicity and immunogenicity of HBsAg. A total of nine mutated HBV s-genes with single representative mutations were generated by site-directed mutagenesis and subcloned into an expression vector. The binding of polyclonal and monoclonal antibodies to these mutant HBsAg (mtHBsAg) was tested by immunofluorescence (IF) staining of cells transfected with the expression vectors. The amino acid (aa) substitutions like G145R, F134S, and C147W affected the binding of anti-HBs antibodies to corresponding mtHBsAg to different extents. The impact of aa substitutions G145R and F134S on the immunogenicity was accessed by genetic immunization of mice with vectors expressing middle HBsAg with the corresponding mutations. The immunized mice developed antibodies to recombinant HBsAg containing the HBV preS region and HBsAg-specific cytotoxic T-cell. However, the development of antibody response to wild-type small HBsAg was significantly impaired by the aa substitutions in HBsAg. Based on this fact, we further investigated whether the mtHBsAg with the aa substitution G145R is able to induce mutant-specific antibody responses. Strikingly, serum samples from mice immunized with mtHBsAg with G145R recognized plasma-derived mtHBsAg. Two mouse MAbs specific to mtHBsAg were generated. One MAb recognized mtHBsAg with G145R but not wild type and other mtHBsAg. We conclude that HBsAg with aa substitutions are immunogenic but may have a changed fine specificity.

The present study shows that feces samples of 14 human volunteers and isolated gut segments of mice (small intestine, cecum, and large intestine) are able to transform metals and metalloids into volatile derivatives ex situ during anaerobic incubation at 37°C and neutral pH. (dry weight) in mouse gut samples, respectively. The upshift of the bismuth content also led to an increase of derivatives of other elements (such as arsenic, antimony, and lead in human feces or tellurium and lead in the murine large intestine). The assumption that the gut microbiota plays a dominant role for these transformation processes, as indicated by the production of volatile derivatives of various elements in feces samples, is supported by the observation that the gut segments of germfree mice are unable to transform administered bismuth to (CH 3 ) 3 Bi.The transformation of metals and metalloids [metal(loid)s] into volatile derivatives by methylation or hydridization plays an important role in spreading and cycling these elements in our natural and anthropogenetically modified environment (6, 25). These transformations are catalyzed to a large part by organisms, mainly by microorganisms growing under anaerobic conditions. Several elements such as arsenic, antimony, bismuth, selenium, tellurium, and mercury are known or thought to be susceptible to these biotransformations (2,5,9,(17)(18)(19)(20)(21)(22)25).

This study investigates the impact of ␣-CGRP on bone metabolism after implantation of polyethylene particles. ␣-CGRP knockout mice showed less osteolysis compared with wildtype mice. The local neurogenic microenvironment might be a crucial factor in particle-induced osteolysis.Introduction: Periprosthetic osteolysis is the major reason for aseptic loosening in joint arthroplasty. This study aimed to investigate the potential impact of ␣-calcitonin gene-related peptide (␣-CGRP) deficiency on bone metabolism under conditions of polyethylene particle-induced osteolysis. Materials and Methods: We used the murine calvarial osteolysis model based on polyethylene particles in 14 C57BL 6 mice and 14 ␣-CGRP-deficient mice divided into four groups of 7 mice each. Groups 1 (C57BL/J 6) and 3 (␣-CGRP knockout) received sham surgery, and groups 2 (C57BL/J 6) and 4 (␣-CGRP knockout) were treated with polyethylene particles. Qualitative and quantitative 3D analyses were performed using CT. In addition, bone resorption was measured within the midline suture by histological examination. The number of osteoclasts was determined by counting the TRACP + cells. Calvarial bone was tested for RANKL expression by RT-PCR and immunocytochemistry. Results: Bone resorption was significantly reduced in ␣-CGRP-deficient mice compared with their corresponding wildtype C57BL 6 mice as confirmed by histomorphometric data (p < 0.001) and CT (p < 0.01). Osteoclast numbers were significantly reduced in group 3 and the particle subgroup compared with group 1 (p < 0.001). We observed a >3-fold increase of basal RANKL mRNA levels within group 1 compared with group 3. Additional low RANKL immunochemistry staining was noted in groups 3 and 4. Conclusions: In conclusion, ␣-CGRP knockout mice did not show the expected extended osteolysis compared with wildtype mice expressing ␣-CGRP. One of the most reasonable explanations for the observed decrease in osteolysis could be linked to the osteoprotegerin (OPG)/RANK/RANKL system in ␣-CGRP-deficient animals. As a consequence, the fine tuning of osteoclasts mediating resorption in ␣-CGRP-null mice may be deregulated.

DNA vaccination is a useful technique to induce potent antigen-specific immune responses and possesses great potential for modification and improvement (2,8,39,42). In general, the application of plasmid DNA by intramuscular injections induces dominantly cell-mediated immune responses, termed Th1-type responses. A number of options are available to modify DNA vaccines, e.g., improvement of antigen expression, coadministration of cytokines, or choice of application routes. An interesting approach is to fuse a bioactive domain, like cytotoxic-T-lymphocyte-associated protein 4 (CTLA-4), to an antigen (1). Such fusion antigens have been shown to bind to antigen-presenting cells expressing B7 molecules on their surfaces (1,7,32,44). Immunization with plasmids expressing fusion proteins with CTLA-4 leads to antigen-specific immune responses, preferentially with an enhanced humoral branch (termed Th2-type responses), though DNA vaccination via the intramuscular route usually induces Th1-type immune responses (1). Thus, the fusion of a specific antigen to CTLA-4 provides a simple but effective modification of DNA vaccines if balanced Th1 and Th2 immune responses are desirable. Such fusion genes showed the ability to induce and modulate antigen-specific immune responses and improved protection against challenges with the respective pathogens (3,7,9). For example, the use of a fusion of CTLA-4 and influenza hemagglutinin for DNA vaccination enhanced the antigen-specific immune response and conferred better protection against influenza virus challenge in mice (7).Hepatitis B virus (HBV) infection is still one of the major infectious diseases worldwide and results in severe liver diseases, cirrhosis, and hepatocellular carcinoma (17). HBV infection in humans can be effectively controlled by vaccination with recombinant HBsAg (43). Immunizations with plasmids expressing the HBV surface antigens (HBsAg) and nucleocapsid protein (HBcAg) effectively induced specific antibody and cytotoxic-T-cell responses to the respective antigens in the mouse model (21,29,40; reviewed in reference 6). However, DNA immunizations in large animals like chimpanzees were not efficient, as plasmids expressing HBsAg had to be applied in a scale of milligrams to induce a measurable anti-HBs antibody response (6, 35). Thus, DNA vaccines against HBV need significant improvements.The woodchuck (Marmota monax) model is an informative animal model used to perform vaccination trials against HBV infection (4, 11, 12, 15, 16, 23-28, 36, 37). Woodchuck hepatitis virus (WHV) causes acute self-limiting and chronic infection, like HBV in humans (reviewed in references 25, 36, and 37). The humoral and cellular immune responses to woodchuck hepatitis surface antigen (WHsAg) and core antigen (WHcAg) in acute and chronic WHV infection are similar to HBV infection. DNA vaccinations of woodchucks with plasmids expressing WHsAg and WHcAg were able to protect against

No abstract

Gamma interferon (IFN-␥

Since the European frogs (Rana spp.) have fallen under the German endangered species regulation, Xenopus laevis (South African Clawed Frog) is being used increasingly in animal research and education. Optimal growth rates and homogeneity of groups have not necessarily been attained as little statistical analysis of growth data has been available. Following metamorphosis, an as yet not understood variability of growth is exhibited by X. laevis. In this study the effect of environmental factors on this variability was determined. Feeding, population density, background colouring, water temperature, the availability of hiding places, water level and water care were each examined separately. Development of body weight and body length were recorded. A definite correlation between the feeding programme, population density, cover and water care on the one hand and growth on the other were seen. Of lesser importance were water temperature, water level and background colouring. The observed variability of growth is assumed to also be of ethological origin.