Lone star tick-infecting borreliae are most closely related to the agent of bovine borreliosis

Although Borrelia theileri, the agent of bovine borreliosis, was described at the turn of the century (in 1903), its relationship with borreliae causing Lyme disease or relapsing fever remains undescribed. We tested the previously published hypothesis that spirochetes infecting Lone Star ticks (Amblyomma americanum) may comprise B. theileri by analyzing the 16S ribosomal DNAs (rDNAs) and flagellin genes of these spirochetes. B. theileri, the Amblyomma agent, and B. miyamotoi formed a natural group or clade distinct from but most closely related to that of the relapsing fever spirochetes. B. theileri and the Amblyomma agent were 97 and 98% similar at the nucleotide level within the analyzed portions of the 16S rDNA and the flagellin gene respectively, suggesting a recent divergence. The agent of bovine borreliosis might be explored as a surrogate antigen for the as-yet-uncultivatable Amblyomma agent in studies designed to explore the etiology of a Lyme disease-like infection associated with Lone Star ticks.     

High rates of clustering of strains causing tuberculosis in Harare, Zimbabwe: a molecular epidemiological study

We examined the pattern of tuberculosis (TB) transmission (i.e., reactivation versus recent transmission) and the impact of human immunodeficiency virus (HIV) infection in Harare, Zimbabwe. Consecutive adult smear-positive pulmonary TB patients presenting to an urban hospital in Harare were enrolled. A detailed epidemiological questionnaire was completed, and tests for HIV type 1 and CD4 cell counts were performed for each patient. Molecular fingerprinting of the genomic DNA recovered from cultures of sputum was performed by two molecular typing methods: spacer oligonucleotide typing (spoligotyping) and analysis of variable number of tandem DNA repeats (VNTRs). A cluster was defined as isolates from two or more patients that shared the same spoligotype pattern or the same VNTR pattern, or both. DNA suitable for typing was recovered from 224 patients. The prevalence of HIV infection was 79%. Of 187 patient isolates (78.6%) typed by both spoligotyping and analysis of VNTRs, 147 were identified as part of a cluster by both methods. By spoligotyping alone, 84.1% of patient isolates were grouped into 20 clusters. The cluster size was generally <8 patient isolates, although three large clusters comprised 68, 25, and 23 patient isolates. A total of 89.4% of the patient isolates grouped into 12 clusters defined by analysis of VNTRs, with 2 large clusters consisting of 127 and 13 patient isolates, respectively. Thirty-six percent of patient isolates with a shared spoligotype and 17% with a shared VNTR pattern were geographically linked within Harare, but they were not linked on the basis of the patient's home district. In a multivariate analysis, there were no independent predictors of clustering, including HIV infection status. Comparison with the International Spoligotype database (Pasteur Institute, Pointe a Pitre, Guadeloupe) demonstrated that our three largest spoligotype clusters are well recognized and ubiquitous in Africa. In this epidemiologically well characterized urban population with a high prevalence of HIV infection, we identified a very high level of strain clustering, indicating substantial ongoing recent TB transmission. Geographic linkage could be detected in a proportion of these clusters. A small group of actively circulating strains accounted for most of the cases of TB transmission.     

Physiological response and childhood anxiety: association with symptoms of anxiety disorders and cognitive bias.

This study examined the physiological response (skin conductance and heart rate [HR]) of youth exposed to a mildly phobic stimulus (video of a large dog) and its relation to child- and parent-reported anxiety symptoms and cognitive bias in a community-recruited sample of youth (n = 49). The results of this study indicated that HR and skin-conductance response were associated with youth report but not parent report of their child's symptoms of anxiety disorders and that HR response was more strongly associated with anxiety symptoms than skin-conductance response. Physiological response was uniquely associated with youth-reported symptoms of anxiety rather than youth-reported depression. Finally, HR response interacted with cognitive bias in predicting childhood anxiety disorder symptoms in a manner consistent with theories of the etiology of anxiety disorders.     

Differences in mouse interferons according to cell source and mode of induction.

Mouse interferon induced by ultraviolet-irradiated Newcastle disease virus or polyriboinosinic-polyribocytidylic acid in T lymphocytes, B lymphocytes, macrophages, and primary mouse embryonic cell culture was studied. Irrespective of the inducer, interferons produced by T or B lymphocytes were relatively heat stable and of low antigenicity when reacted with antiserum against L-cell interferon (ALI), whereas interferons produced by macrophages and mouse embryo cells were heat labile and of high antigenicity against ALI. Mouse interferons induced by ultraviolet-irradiated Newcastle disease virus were separated into three components by chromatography on CH-Sepharose 4B. Interferons produced by T and B lymphocytes consisted primarily of component 1 (unbound fraction), whereas interferons produced by macrophages or mouse embryo cells consisted primarily of component 3 (eluted by 0.5 M NaCl). Component 1 was heat stable and of low antigenicity against ALI, properties characteristic of T- and B-cell interferon. Components 2 and 3 were heat labile and of high antigenicity against ALI, properties characteristic of macrophage and mouse embryo cell interferon. In contrast, interferon induced in mice sensitized with BCG differed from these interferons induced in B cells, T cells, macrophages, and fibroblasts in being extremely acid labile and nonreactive against ALI.     

Fc receptors on the surface of Toxoplasma gondii trophozoites: a confounding factor in testing for anti-Toxoplasma antibodies by indirect immunofluorescence.

Negative sera often produce false-positive polar patterns of fluorescence in indirect immunofluorescence tests for serum anti-Toxoplasma gondii antibodies, representing a confounding factor in the diagnosis of toxoplasmosis. In this work, we studied whether T. gondii trophozoites, the antigenic material used in the immunofluorescence tests, expressed surface Fc receptors that could cause the binding of normal immunoglobulins, thus producing false-positive results. We report here that T. gondii trophozoites indeed have Fc receptors on their surface. This was shown by the direct binding of purified human Fc to the parasite, evidenced by the subsequent binding of fluorescein-labeled Fab specific for human Fc. In addition, pretreatment of the parasite with excess purified Fc to saturate the surface Fc-binding sites abrogated the formation of polar fluorescence. The trophozoites appeared to express Fc receptors with different degrees of affinity for the specific ligand, since a diffuse fluorescence pattern was observed following incubation with 1 mg of Fc per ml (10 micrograms per well), whereas with 0.2 mg (0.2 micrograms per well), a majority of parasites showed polar fluorescence. This observation suggests that the Fc receptors accumulated at the polar cap are those with higher affinity. The present findings raise intriguing questions regarding the possible biological role(s) of the Fc receptors on T. gondii but, more immediately, indicated that pretreatment of the antigenic material with Fc, a commercially available reagent, constitutes a practical, simple way to avoid false-positive immunofluorescence test results due to the binding of nonspecific immunoglobulin to the parasite.     

Association of DLG5 R30Q variant with inflammatory bowel disease

Crohn's disease (CD) and ulcerative colitis (UC) are chronic inflammatory diseases of the gastrointestinal system known as the inflammatory bowel diseases (IBD). Recently, Stoll and colleagues reported a novel finding of genetic variation in the DLG5 gene that is associated with IBD (CD and UC combined). We present here a study of the genetic variation described in that report in two well-powered, independent case-control cohorts and one family-based collection, and confirm the proposed association between IBD and the R30Q variant of DLG5 in two of the three studies. We are, however, unable to replicate the other proposed association to the common haplotype described in Stoll et al and suggest that this other finding could conceivably have been partially a statistical fluctuation and partially a result of LD with the replicated R30Q association. This study provides support for the hypothesis that DLG5 constitutes a true IBD risk factor of modest effect.     

Choline acetyltransferase immunoreactivity in neuritic plaques of Alzheimer brain

We have observed dystrophic choline acetyltransferase (ChAT)-positive processes surrounding the amyloid core of neuritic plaques in human neocortex, amygdala and hippocampus, using a polyclonal anti-human ChAT antiserum. These data, and those from studies of the aged monkey by other investigators, provide a morphologic counterpart for the biochemical abnormality of the cholinergic system in Alzheimer's disease and senile dementia of the Alzheimer type.     

Cystic fibrosis: Synthesis of ciliary inhibitor by amniotic cells

The presence of a ciliary inhibitor in media of cultured amniotic cells obtained from a fetus heterozygous for cystic fibrosis has been observed by the oyster gill cilia assay. The chromatographic fraction containing the inhibitor corresponded to eluted fractions chromatographed from cystic fibrosis fibroblast media and serum. An analogous chromatographic fraction from media of cultured amniotic cells from two proportedly normal fetuses did not inhibit cilia. The chromatographic fraction from media of cultured amniotic cells of a fetus at high risk for cystic fibrosis did not inhibit ciliary activity. Serum was collected from this baby seven weeks after birth and also did not inhibit ciliary action, indicating a homozygous normal genotype. These observations may lead to the development of an antenatal test for cystic fibrosis.