Biomedical subjects

Gema Lorenzo

Publications and source records attributed to Gema Lorenzo.

4 recordsLinked to original sources

PubMed2006

Complex clonal features in an mycobacterium tuberculosis infection in a two-year-old child.

The focus of this report is to describe the highly complex clonal features of the Mycobacterium tuberculosis (MTB) isolates cultured from a 2-year-old child with no risk factors for tuberculosis. Molecular analysis showed that she was coinfected by 2 MTB isolates. The coinfecting isolates showed only subtle genetic differences and shared equivalent infectivity in vitro; however, they were infecting independent anatomic sites (compartmentalized infection). One of the MTB isolates was cultured only from respiratory specimens, whereas the other was isolated from extrarespiratory site (central nervous system).

Bacterial Typing Techniques↗

PubMed2005

Association between the infectivity of Mycobacterium tuberculosis strains and their efficiency for extrarespiratory infection.

Extrarespiratory tuberculosis is determined mainly by impaired immunity of the host. The additional role played by bacterial factors in determining whether an infection by Mycobacterium tuberculosis disseminates to extrarespiratory sites has not been analyzed in depth. In the present study, we selected patients who were dually infected with 2 M. tuberculosis strains but in whom only one of the strains infected extrarespiratory sites, whereas the other strain remained at the respiratory site. We compared the infectivity of respiratory and extrarespiratory strains in a newly designed ex vivo competitive macrophage coinfection assay and in the murine aerosol-infection model. The extrarespiratory strains infected macrophages more efficiently than did the respiratory strains, and a representative extrarespiratory strain also showed higher infectivity in vivo. Our data indicate that, in addition to host immune status, a bacterial factor--the infectivity of a M. tuberculosis strain--should be considered in determining the likelihood of extrarespiratory dissemination.

Animals↗

PubMed2003

Evolution of complement as an effector system in innate and adaptive immunity.

For a long time, the complement system in mammals has been regarded as a biological system that plays an essential role in innate immunity. More recently, it has been recognized that the complement system contributes heavily to the generation and development of an acquired immune response. In fact, this ancient mechanism of defense has evolved from a primitive mechanism of innate immune recognition in invertebrate species to that of an effector system that bridges the innate with the adaptive immune response in vertebrate species. When and how did complement evolve into a shared effector system between innate and adaptive immunity? To answer this question, our group is interested in understanding the role of complement in innate and adaptive immune responses in an evolutionary relevant species: the teleost fish. The attractiveness of this species as an animal model is based on two important facts. First, teleost fish are one of the oldest animal species to have developed an adaptive immune response. Second, the complement system of teleost fish offers a unique feature, which is the structural and functional diversity of its main effector protein, C3, the third component of the complement system.

Animals↗

PubMed2000

Sequence of the Small Subunit Ribosomal RNA Gene of Perkinsus atlanticus-like Isolated from Carpet Shell Clam in Galicia, Spain.

Parasites identified as Perkinsus atlanticus have been reported infecting carpet shell clams in Galicia (northwest Spain). We have sequenced the 18S ribosomal RNA gene of in vitro cultured Perkinsus atlanticus-like or hypnospores from diseased clams, and compared it with the same genomic region from P. marinus and Perkinsus sp. We have also compared the sequence of internal transcribed spacer (ITS) 1, ITS 2, and 5.8S rRNA from our isolate with the P. atlanticus GenBank sequence. The phylogenetic analysis of our cultured parasite based on the 18S gene led us to conclude that this isolate is not related to the genus Perkinsus but to the protists Anurofeca, Ichthyophonus, and Psorospermium, located near the animal-fungal divergence. These last two genera have been included, together with Dermocystidium, in the newly described DRIPs (Dermocystidium, rossete agent, Ichthyophonus, and Psorospermium) clade, recently named Mesomycetozoa.

Journal Article↗