Induction and expression of protective T cells during Mycobacterium avium infections in mice.

Mycobacterium avium is an opportunistic pathogen that infects individuals suffering from chronic lung disease or immunocompromised patients such as AIDS patients. Here we show that a highly virulent isolate of M. avium proliferated as extensively in T cell deficient as in immunocompetent mice. T cell deficient mice allowed a progressive growth of a less virulent AIDS-derived isolate of M. avium while immunocompetent mice arrested the growth of this isolate. Adoptive transfer of T cell enriched spleen cells between congenic strains of mice differing at the Bcg/Ity/Lsh locus showed that only naturally resistant BALB/c.Bcgr (C.D2) mice infected with the highly virulent strain of M. avium or the naturally susceptible BALB/c mice infected with the lower virulence isolate developed protective T cells and that these cells only mediated protection when transferred to naturally susceptible, but not to naturally resistant, mice. Both strains of M. avium proliferated in bone marrow-derived macrophages cultured in vitro and they were both susceptible to the bacteriostatic effects induced in the macrophages by crude lymphokines produced by concanavalin A-stimulated spleen cells.     

CT evaluation of gastric wall pathology

The purpose of this study is to show the CT features of common and infrequent pathological lesions of the gastric wall. Although CT features are not often specific, familiarity with the most frequent pathological gastric findings on CT can assist in differential diagnosis.     

Multiple myeloma in an adolescent

The radiographic findings of a 15-year-old Brazilian male with diagnosis of multiple myeloma are described. He presented with claudication and recent onset of tender painful swelling of the right mid leg. Radiographs showed wide spread soap bubble lesions of the skull, long bones, spine, pelvis, ribs, shoulders, and clavicles. The diagnosis was confirmed by the presence of a plasmacytoma on tissue biopsy (femur), serum IgG gammopathy and Bence-Jones proteinuria.Supported by grants (CA-20180 and CA-21765) from the National Cancer Institute and the American Lebanese Syrian Associated Charities (ALSAC)     

Analytical validation of anti-toxoplasma IgG immunoassays

There are often discrepancies when using different methods to measure anti-Toxoplasma gondii IgG levels in patient samples. The diagnostic performance of a chemiluminescent immunoassay (CLIA) and an enzyme-linked fluorescent assay (ELFA) used as confirmatory tests for samples identified as positive or equivocal by an electrochemiluminescent immunoassay (ECLIA) were examined. Cut-off values were those stated by the manufacturer, and Western blot was used to confirm the results of all methods. All samples identified as positive by ECLIA (n = 93) were confirmed as positive by Western blot, as were 14 of the 28 samples identified as equivocal. When these 121 samples were retested, the sensitivities of CLIA and ELFA were 64.4% and 73.8%, respectively. Both methods exhibited a specificity of 100%. This study confirms that the results obtained from the different immunoassays are not comparable, and neither CLIA nor ELFA should be used to confirm ECLIA results, which should instead be confirmed by methods such as Western blot or Sabin-Feldman dye test.     

Survey of Schizophrenia and Bipolar Disorder Candidate Genes using Chromatin Immunoprecipitation and Tiled Microarrays (ChIP-chip)

It has been difficult to identify disease-causing alleles in schizophrenia (SZ) and bipolar disorder (BD) candidate genes. One reason is that responsible functional variants may exist in unidentified regulatory domains. With the advent of microarray technology and high throughput sequencing, however, it is now feasible to screen genes for such regulatory domains relatively easily by using chromatin immunoprecipitation–based methodologies, such as ChIP-chip and ChIP-seq. In ChIP-chip, regulatory sequences can be captured from chromatin immunoprecipitates prepared with antibodies against covalently modified histones that mark certain regulatory domains; DNA extracted from such immunoprecipitates can then be used as microarray probes. As a first step toward demonstrating the feasibility of this approach in psychiatric genetics, we used ChIP-chip to identify regulatory domains in several candidate genes: NRG1, DTNBP1, DISC1, DAO, DAOA, PDE4B, and COMT. Immunoprecipitates were generated with antibodies to histone H3 acetylated at lysine 9 (H3K9Ac) and histone H3 monomethylated at lysine 4 (H3K4me1), which mark promoters and some enhancers, using fetal brain chromatin as a substrate. Several novel putative regulatory elements, as well as the core and proximal promoters for each gene, were enriched in the immunoprecipitates. Genetic variants within these regions would be of interest to study as potential disease-associated alleles.     

Salience in a social landscape: electrophysiological effects of task-irrelevant and infrequent vocal change

In a dynamically changing social environment, humans have to face the challenge of prioritizing stimuli that compete for attention. In the context of social communication, the voice is the most important sound category. However, the existing studies do not directly address whether and how the salience of an unexpected vocal change in an auditory sequence influences the orientation of attention. In this study, frequent tones were interspersed with task-relevant infrequent tones and task-irrelevant infrequent vocal sounds (neutral, happy and angry vocalizations). Eighteen healthy college students were asked to count infrequent tones. A combined event-related potential (ERP) and EEG time–frequency approach was used, with the focus on the P3 component and on the early auditory evoked gamma band response, respectively. A spatial-temporal principal component analysis was used to disentangle potentially overlapping ERP components. Although no condition differences were observed in the 210–310 ms window, larger positive responses were observed for emotional than neutral vocalizations in the 310–410 ms window. Furthermore, the phase synchronization of the early auditory evoked gamma oscillation was enhanced for happy vocalizations. These findings support the idea that the brain prioritizes the processing of emotional stimuli, by devoting more attentional resources to salient social signals even when they are not task-relevant.