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Biomedical subjects

Beatriz López

Publications and source records attributed to Beatriz López.

6 recordsLinked to original sources
PubMed2005

In-house phage amplification assay is a sound alternative for detecting rifampin-resistant Mycobacterium tuberculosis in low-resource settings.

An in-house mycobacteriophage amplification assay for detecting rifampin-resistant Mycobacterium tuberculosis showed 100% sensitivity, 97.7% specificity, and 95.2% predictive value for resistance in a test of 129 isolates from a hot spot area of multidrug-resistant M. tuberculosis. The applicability of the test was demonstrated in the routine work flow of a low-resource reference laboratory.

Antibiotics, Antitubercular↗
PubMed2004

Multicenter evaluation of mycobacteria identification by PCR restriction enzyme analysis in laboratories from Latin America and the Caribbean.

The identification of mycobacterial species in clinical isolates is essential for making patient care decisions. Polymerase chain reaction (PCR) restriction enzyme analysis (PRA) is a simple and rapid identification method, based on amplification of 441 bp of the hsp65 gene and restriction with BstEII and HaeIII. As a contribution to the validation of PRA, a multicenter study was performed in eight laboratories located in Argentina, Brazil, Colombia, Chile, and Guadeloupe. Each laboratory received 18 coded isolates from the collection of the Institute of Tropical Medicine (Antwerp, Belgium), representing duplicates of nine laboratory strains: Mycobacterium terrae CIPT 140320001, Mycobacterium scrofulaceum CIPT 140220031, Mycobacterium flavescens ATCC 14474, Mycobacterium triviale ATCC 23292, Mycobacterium nonchromogenicum ATCC 19530, Mycobacterium chitae ATCC 19627, Mycobacterium abscessus ATCC 19977, Mycobacterium kansasii ATCC 12478, and Mycobacterium peregrinum ATCC 14467. A detailed protocol including amplification, enzymatic digestion, and gel preparation was provided to each laboratory. Two laboratories identified correctly all 18 (100%) isolates, one identified correctly 17 (94.5%), two identified 14 (77.7%), one identified 11 (61%), and two identified 8 (44.4%) isolates. Errors detected in laboratories with more than 77% accuracy were associated with electrophoresis running conditions and an unspecific amplicon produced by a single strain. Lower accuracy was mainly related to inappropriate use of DNA markers and insufficient training in interpretation of patterns. In conclusion, the PRA method was readily implemented in some Latin American and Caribbean laboratories of mycobacteria, but improvements in critical points, as gel running conditions and training in interpretiation of patterns, are needed in order to improve accuracy. In others, improvement in critical points is still necessary.

Bacterial Proteins↗
PubMed2003

Do children with autism fail to process information in context?

BACKGROUND: This research investigated the proposal that children with autism are impaired in processing information in its context. To date, this proposal rests almost exclusively on evidence from verbal tasks. Given evidence of visuo-spatial proficiency in autism in other areas of functioning, it is possible that the ability to use context is spared in the visual domain but impaired in the verbal domain. METHOD: Fifteen children with autism and 16 age and IQ-matched typically developing children were tested on their ability to take account of visual context information (Experiment 1) and verbal context information (Experiment 2) using an adaptation of Palmer's (1975) visual context task. They were also given an adaptation of Tager-Flusberg's (1991) visual and verbal semantic memory task (Experiment 3) and Frith and Snowling's (1983) homograph task (Experiment 4). RESULTS: Experiment 1 showed that children with autism were facilitated by the provision of visual context information. Experiments 2 and 3 showed that the same children were also able to use both verbal context information when identifying words and semantic category information in a verbal task when naming and recalling words. However, in Experiment 4 these children had difficulties with a sentence-processing task when using sentence context to disambiguate homographs. CONCLUSIONS: These findings demonstrate that children with autism do not have a general difficulty in connecting context information and item information as predicted by weak central coherence theory. Instead the results suggest that there is specific difficulty with complex verbal stimuli and in particular with using sentence context to disambiguate meaning.

Autistic Disorder↗
PubMed2003

Confirmed detection of Cyclospora cayetanesis, Encephalitozoon intestinalis and Cryptosporidium parvum in water used for drinking.

Human enteropathogenic microsporidia (HEM), Cryptosporidium parvum, Cyclospora cayetanesis, and Giardia lamblia are associated with gastrointestinal disease in humans. To date, the mode of transmission and environmental occurrence of HEM (Encephalitozoon intestinalis and Enterocytozoon bieneusi) and Cyclospora cayetanesis have not been fully elucidated due to lack of sensitive and specific environmental screening methods. The present study was undertaken with recently developed methods, to screen various water sources used for public consumption in rural areas around the city of Guatemala. Water concentrates collected in these areas were subjected to community DNA extraction followed by PCR amplification, PCR sequencing and computer database homology comparison (CDHC). All water samples screened in this study had been previously confirmed positive for Giardia spp. by immunofluorescent assay (IFA). Of the 12 water concentrates screened, 6 showed amplification of microsporidial SSU-rDNA and were subsequently confirmed to be Encephalitozoon intestinalis. Five of the samples allowed for amplification of Cyclospora 18S-rDNA; three of these were confirmed to be Cyclospora cayetanesis while two could not be identified because of inadequate sequence information. Thus, this study represents the first confirmed identification of Cyclospora cayetanesis and Encephalitozoon intestinalis in source water used for consumption. The fact that the waters tested may be used for human consumption indicates that these emerging protozoa may be transmitted by ingestion of contaminated water.

Animals↗