1,721,136 research outputs found
Antigen-coated latex particles as a model system for probing monocyte responses in leprosy
No full textTo study responses to Mycobacterium leprae antigens, we developed an in vitro model system in which latex particles coated with M. leprae sonic extract (MLSON) antigen were presented to monocytes. Uptake and oxidative response as measured by superoxide production to these antigens were investigated. Phagocytosis of MLSON-coated particles was greater than that of control particles in monocytes from both leprosy patients and controls from leprosy-endemic areas; uptake of MLSON-coated particles was higher in monocytes from lepromatous leprosy patients than in cells from tuberculoid leprosy patients and controls. In both patients and controls, uptake of latex particles coated with leprosy antigens triggered very little reduction of nitroblue tetrazolium although the cells were capable of mounting a respiratory burst. Antigen-coated latex particles can therefore be used as a tool to investigate monocyte responses to M. leprae and individual recombinant antigens.Peer reviewedfinal article publishe
Detection of high titres of Toxoplasma gondii antibodies in sera of patients with leprosy in Pakistan
No full textUntreated and treated leprosy patients and their household contacts were screened for antibody to Toxoplasma gondii using antigen-coated latex particles. A significantly high level of seroprevalence (29·6%) was observed in the untreated leprosy patients compared to endemic controls (P < 0·01) with a mean reciprocal antibody titre of 20 007 ± 3580 (n = 98) in seropositive patients. In treated patients seroprevalence dropped to 13·5%. Seroprevalence in a group of household contacts of leprosy patients was similar to that of control subjects from an endemic area but not exposed to leprosy (7·8% and 6·1% respectively), indicating that the increased seroprevalence in leprosy patients was not merely due to increased exposure related to socioeconomic factors. Antigenic cross-reactivity between T. gondii and Mycobacterium leprae antigens was ruled out by cross inhibition experiments carried out with soluble antigens from each of the organisms. We believe these antibodies may be induced by an increase in T. gondii load in leprosy due to a transient reactivation of latent T. gondii infections, as the antibodies in these leprosy patients were not associated with any sign of eye or lymphatic pathology related to toxoplasmosis.Peer reviewedfinal article publishe
Quantitation of IgM antibodies to the M. leprae synthetic dissacharide can predict early bacterial multiplication in leprosy
No full textQuantitative enzyme-linked immunosorbent assays detecting IgM to the soluble Mycobacterium leprae crude sonicate (CD75) and the synthetic disaccharide antigen coupled to bovine serum albumin (ND-BSA) were assessed for their ability to determine early infection in families/household contacts of leprosy patients and employees of a leprosy center working in close contact with leprosy patients. Although IgM to both antigens (CD75 and ND-BSA) correlated with the bacterial index (BI) assessed histologically on skin-biopsy samples, the level of IgM antibodies to ND-BSA was a much more sensitive indicator of low bacterial loads. A 4.4-fold difference in antibody levels was observed between the mean group levels of endemic controls (N = 116) and tuberculoid leprosy patients with a BI of 0 (N = 88), increasing to sevenfold in tuberculoid leprosy patients with a BI of 1 (N = 20). Using a statistical cut off with endemic controls (mean + 2 S.D.), household/family contacts showed 30% seropositivity (N = 180) as compared to staff contacts who showed 17% seropositivity (N = 55). Percent seropositivity in family contacts was not related to the type of leprosy of the index case (lepromatous vs. tuberculoid) or the duration of treatment of the index case. Age of the individual in the family contact group had a significant influence on seropositivity. These results support the hypothesis that, in this community, factors other than the viable bacterial load of the index case, such as genetic susceptibility, may be influencing the high rate of seropositivity in family contacts. IgM ND-BSA antibodies seem to provide a good indicator of low antigenic loads and could prove to be useful in detecting subclinical infection before the onset of dis-ease. Follow-up studies of these seropositive individuals are in progress to understand the relationship between seropositivity and the progress of clinical disease.Peer reviewedfinal article publishe
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Towards new TB vaccines: What are the challenges?
No full textNew and effective tuberculosis (TB) vaccines are urgently needed to control pulmonary TB, and in particular to prevent the spread of drug-resistant strains of Mycobacterium tuberculosis. These drug-resistant strains can range from those resistant to first-line drugs to those that are almost impossible to treat. To develop new and effective vaccines for HIV and malaria has been difficult and it is proving to be just as challenging for TB. TB is a complicated disease with a spectrum from apparently controlled latent infection to active clinical disease and so different types of preventive or post-exposure vaccine may be needed. Identifying the most promising vaccine candidates to move into clinical trials is difficult, as we lack biomarker signatures that can predict protective efficacy. There is a risk that the failure of the MVA-85A vaccine to show efficacy when given to previously BCG-vaccinated South African infants will impact on the resources available for the development and trials of other candidate TB vaccines. Continued support for the development of new TB vaccines should remain a priority as an effective vaccine would bring huge public health benefits
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
- …
