Development of a PCR-based tool for detecting immunologically relevant Alt a 1 and Alt a 1 homologue coding sequences

Alt a 1 has been recognized as the most important allergen produced by the Pleosporaceae family and is a risk factor for asthma development and/or exacerbation. The aim of this study was to develop a detection tool that is highly specific for species that produced airborne Alt a 1. Based on the highly conserved internal nucleotide region of the several Alt a 1 sequences that are available in GenBank, a pair of primers (Alta1CF/Alta1CR) was designed. A set of primers used by other authors for the production of recombinant Alt a 1 (A21F/A21R) was also tested. The molecular analyses were based on the polymerase chain reaction (PCR) amplification and sequencing of the cDNA that was obtained from thirteen common fungal species. The PCR system that utilized Alta1CF/Alta1CR was highly specific, sensitive, and was able to detect an amplicon of approximately 180 bp from Alt a 1 and Alt a 1-like encoding genes from A. alternata, A. tenuissima, A. infectoria, U. botrytis, and S. botryosum. In contrast, the A21F/A21R primers were specific for the very close taxonomically related species A. alternata and A. tenuissima. Thus, this rapid, sensitive, and specific detection tool can be used to assess Alt a 1 exposure levels and to inform the implementation of the appropriate public health measures.

Crystallization and preliminary crystallographic analysis of the measles virus hemagglutinin in complex with the CD46 receptor

The measles virus (MV) hemagglutinin (MV-H) mediates the attachment of MV particles to cell-surface receptors for entry into host cells. MV uses two receptors for attachment to host cells: the complement-control protein CD46 and the signalling lymphocyte activation molecule (SLAM). The MV-H glycoprotein from an Edmonston MV variant and the MV-binding fragment of the CD46 receptor were overproduced in mammalian cells and used to crystallize an MV-H-CD46 complex. Well diffracting crystals containing two complexes in the asymmetric unit were obtained and the structure of the complex was solved by the molecular-replacement method.

Sociodemographic predictors and temporal trends of extrapulmonary tuberculosis as an AIDS-defining disease in Spain

OBJECTIVE

To identify the factors associated with the presentation of extrapulmonary tuberculosis (EPTB) in AIDS diagnosis and to analyse its temporal trend.

DESIGN

Analysis of AIDS surveillance data.

METHODS

The study was based on AIDS cases diagnosed in Spain between 1988 and 1993, and reported up to September 1994. The proportion of patients presenting with EPTB at AIDS diagnosis was analysed by sociodemographic characteristics and year of diagnosis.

RESULTS

Of the 22,445 AIDS cases diagnosed in Spain from 1988 to 1993, 6526 patients (29.1%; 95% confidence interval, 28.5-29.7) presented with EPTB at diagnosis, making it the most frequent AIDS-defining disease. The highest proportions of EPTB reported at AIDS diagnosis were observed for injecting drug users (IDU; 35.4%) and the heterosexual transmission category (23.5%). The proportion of EPTB was lower in women [relative risk (RR), 0.85; P < 0.001], and higher in 15-29-year-olds (34.2%) and patients with a prison record (44.3 versus 25.4%; RR, 1.75; P < 0.001). AIDS patients resident in provinces with high respiratory TB mortality rates among the general population exhibited a higher proportion of EPTB (RR, 1.45; P < 0.001). The effect of any one variable was maintained by controlling for all others. The proportion of patients with EPTB at AIDS diagnosis revealed a downward trend from 1988 to 1993 (P = 0.007), which was observed in IDU and heterosexuals but not in homosexual/bisexual men (P = 0.421).

CONCLUSIONS

Factors such as injecting drug use, prison record or residence in high TB-endemic areas are associated with a greater frequency of EPTB at AIDS diagnosis. These factors must be considered for specific prophylaxis to be efficiently applied.