Modulation of resistance to Salmonella typhimurium infection in mice by mouse hepatitis virus (MHV)

Prior infection of mice with a field strain of mouse hepatitis virus (MHV) increased the early resistance of euthymic mice to virulent Salmonella typhimurium strain SR-11 infections (as defined by significantly fewer salmonella colony-forming units (cfu) present in spleens and livers 4 days after salmonella infection). This increase in salmonella resistance was observed when the interval between MHV and salmonella infections was 6 days, but not at 3, 10, or 14 day intervals. The mouse Ity locus, which controls the number of intracellular salmonella, had a significant effect on the ability of MHV to induce resistance to salmonella. MHV caused an increase in resistance to salmonella in Itys (salmonella susceptible) mice at all doses of salmonella tested (100 to 10,000 cfu). In the Ityr (salmonella resistant) mice tested the beneficial effect of MHV on salmonella resistance was small and when observed, was only present at salmonella doses of 10,000 cfu or greater. Neither the Lpsd nor Xid mutations affected the ability of MHV to increase resistance to salmonella infection. In contrast to euthymic mice, MHV infection greatly decreased the resistance of athymic (nude) mice to salmonella infection. Since the Nu locus does not affect the resistance of mice to salmonella (at 4 days post salmonella infection), these results indicate that MHV infection and the nude phenotype interact to increase susceptibility to salmonella. These findings re-emphasize the importance of keeping laboratory mice used in research free of MHV and other immunomodulatory pathogens.     

The effect of automated landmark identification on morphometric analyses

Morphometric analysis of anatomical landmarks allows researchers to identify specific morphological differences between natural populations or experimental groups, but manually identifying landmarks is time‐consuming. We compare manually and automatically generated adult mouse skull landmarks and subsequent morphometric analyses to elucidate how switching from manual to automated landmarking will impact morphometric analysis results for large mouse (Mus musculus) samples (n = 1205) that represent a wide range of ‘normal’ phenotypic variation (62 genotypes). Other studies have suggested that the use of automated landmarking methods is feasible, but this study is the first to compare the utility of current automated approaches to manual landmarking for a large dataset that allows the quantification of intra‐ and inter‐strain variation. With this unique sample, we investigated how switching to a non‐linear image registration‐based automated landmarking method impacts estimated differences in genotype mean shape and shape variance‐covariance structure. In addition, we tested whether an initial registration of specimen images to genotype‐specific averages improves automatic landmark identification accuracy. Our results indicated that automated landmark placement was significantly different than manual landmark placement but that estimated skull shape covariation was correlated across methods. The addition of a preliminary genotype‐specific registration step as part of a two‐level procedure did not substantially improve on the accuracy of one‐level automatic landmark placement. The landmarks with the lowest automatic landmark accuracy are found in locations with poor image registration alignment. The most serious outliers within morphometric analysis of automated landmarks displayed instances of stochastic image registration error that are likely representative of errors common when applying image registration methods to micro‐computed tomography datasets that were initially collected with manual landmarking in mind. Additional efforts during specimen preparation and image acquisition can help reduce the number of registration errors and improve registration results. A reduction in skull shape variance estimates were noted for automated landmarking methods compared with manual landmarking. This partially reflects an underestimation of more extreme genotype shapes and loss of biological signal, but largely represents the fact that automated methods do not suffer from intra‐observer landmarking error. For appropriate samples and research questions, our image registration‐based automated landmarking method can eliminate the time required for manual landmarking and have a similar power to identify shape differences between inbred mouse genotypes.     

Suppressed Cell-Mediated Immunity and Monocyte and Natural Killer Cell Activity Following Allogeneic Immunization of Women with Spontaneous Recurrent Abortion

Spontaneous recurrent abortion (SRA) has been treated by means of immunization with paternal or third-party white blood cells, yet the immunological basis for SRA and for the role of immunization protocols in pregnancy outcome remains controversial. To elucidate this question, nine women with SRA were immunized with paternal mononuclear cells and studied before and 2 weeks after immunization. Seven women who became pregnant gave birth to live newborns. Secretion of the T helper 1 cytokines IL-2 and interferon- by patients' mononuclear cells decreased, while production of IL-10 increased. The levels of natural killer and lymphokine-activated killer cell-mediated cytotoxicity were markedly decreased. Monocyte functions such as secretion of IL-l, tumor necrosis factor a, IL-6, and cytotoxic activity decreased concurrently with elevations in IL-10 and transforming growth factor secretion. Production of IL-12, a pivotal regulatory cytokine, decreased. Furthermore, B7/1 expression on patients' mononuclear cells was downregulated. This resulted in a decrease in monocyte costimulatory activity of purified T cells with soluble anti-CD3, paralleled by a decline in allogeneic proliferative responses. These results suggest that the improved pregnancy success rate in women with SRA following immunization may be partly related to suppression of cell-mediated immunity and monocyte and natural killer cell activity.     

The functional anatomy of the human anterior talofibular ligament in relation to ankle sprains

The anterior talofibular ligament is the most commonly injured ligament in the ankle. Despite considerable interest in the clinical outcome of treatment protocols, we do not know whether the distinctive pattern of localization of the injuries relates to regional differences in the structure and molecular composition of the ligament. To address this issue, ligaments were examined by histology and immunohistochemistry. Differences in the structure of its two attachments (i.e. entheses) were evaluated with quantitative, morphometric techniques, and regional differences in the distribution of collagens, glycosaminoglycans and proteoglycans were determined qualitatively by immunolabelling. Morphometric analyses showed that bone density was less at the fibular attachment, but that enthesis fibrocartilage was more prominent. Immunohistochemistry revealed the presence of a fibrocartilage (containing type II collagen and aggrecan) at the site where the ligament wraps around the lateral talar articular cartilage in a plantarflexed and inverted foot: the fibrocartilage is regarded as an adaptation to resisting compression. We propose that avulsion fractures are less common at the talar end of the ligament because (1) bone density is greater here than at the fibular enthesis, and (2) stress is dissipated away from the talar enthesis by the 'wrap-around' fibrocartilaginous character of the ligament near the talar articular facet.     

Monoclonal antibodies to bovine serum albumin: affinity and specificity determinations

A panel of 12 monoclonal antibodies (MAb) to bovine serum albumin (BSA) was developed and characterized as to their physiochemical and immunological properties. Affinity constants of the MAb varied over a wide range from 10(5) to 10(8) M-1. MAb were assembled into several groups of non- or minimally interacting antibodies by analysis of competitive binding experiments, and BSA domain and subdomain specificities of the MAb were assigned by analysis of results of MAb binding to purified BSA fragments. Further fine specificity delineation was accomplished by examination of cross-reactivity patterns to several mammalian albumins. The data suggest that some of the low affinity MAb recognize sites on different portions of the BSA molecule, indicating that similar epitopes exist on different domains of the BSA molecule.     

Evaluation of the single radial haemolysis (SRH) technique for rubella antibody measurement.

Sera from 1258 individuals have been tested by four laboratories for rubella antibody by both the haemagglutination-inhibition and single radial haemolysis techniques. There was good agreement between the results obtained by the two methods. Although sheep red blood cells were used in the single radial haemolysis plates, no problems were encountered with sera from patients with infectious mononucleosis. The single haemolysis technique was found to be simple, convenient, and reliable, and suited to the rapid screening of large numbers of sera to assess susceptibility to rubella in the context of a vaccination campaign. However, since the technique does not detect anti-rubella IgM, it should not be used as the only test to investigate suspected recent infection.