Biomedical subjects

Helen C Wainwright

Publications and source records attributed to Helen C Wainwright.

3 recordsLinked to original sources

PubMed2006

A multidrug-resistant, acr1-deficient clinical isolate of Mycobacterium tuberculosis is unimpaired for replication in macrophages.

Multidrug-resistant tuberculosis (MDR-TB) poses a serious threat to global public health. The mutations responsible for drug resistance in Mycobacterium tuberculosis have been identified, but what impact these mutations have on bacterial fitness is controversial. We analyzed 3 MDR strains of M. tuberculosis obtained from human immunodeficiency virus-negative patients with chronic pulmonary TB. One of these strains harbored a chromosomal deletion encompassing 15 open reading frames. Genes deleted in this strain included acr1, which encodes the virulence factor alpha-crystallin (Acr) 1, a protein that has been reported to be essential for M. tuberculosis replication in macrophages. We found that all 3 MDR isolates, including the acr1-deficient strain, replicated in cultured murine and human macrophages with the same kinetics as H37Rv, a virulent laboratory strain. These observations challenge the prevailing view that MDR bacteria are less fit than drug-susceptible bacteria and indicate that Acr1 is dispensable for bacterial growth in the human lung.

Animals↗

PubMed2003

Differential expression of iron-, carbon-, and oxygen-responsive mycobacterial genes in the lungs of chronically infected mice and tuberculosis patients.

Pathogenetic processes that facilitate the entry, replication, and persistence of Mycobacterium tuberculosis (MTB) in the mammalian host likely include the regulated expression of specific sets of genes at different stages of infection. Identification of genes that are differentially expressed in vivo would provide insights into host-pathogen interactions in tuberculosis (TB); this approach might be particularly valuable for the study of human TB, where experimental opportunities are limited. In this study, the levels of selected MTB mRNAs were quantified in vitro in axenic culture, in vivo in the lungs of mice, and in lung specimens obtained from TB patients with active disease. We report the differential expression of MTB mRNAs associated with iron limitation, alternative carbon metabolism, and cellular hypoxia, conditions that are thought to exist within the granulomatous lesions of TB, in the lungs of wild-type C57BL/6 mice as compared with bacteria grown in vitro. Analysis of the same set of mRNAs in lung specimens obtained from TB patients revealed differences in MTB gene expression in humans as compared with mice.

Animals↗

PubMedDate not supplied

Facio-auriculo-vertebral sequence in association with DiGeorge sequence, Rokitansky sequence, and Dandy-Walker malformation: case report.

Extreme variability of expression is characteristic of the facio-auriculo-vertebral sequence. Sporadic and familial cases have been reported with obvious etiologic heterogeneity. Most reports in the literature are of clinical cases. The purpose of this paper is to present a fetal autopsy case report of the facio-auriculo-vertebral sequence in association with DiGeorge sequence, Rokitansky sequence, and Dandy-Walker malformation. A standard neonatal autopsy was performed on a macerated female fetus, gestational age 29 wk. External examination of the fetus revealed hypoplastic right face, low-set microtic right ear, and macrostomia. Internal examination showed hypoplastic thymus and lungs, a type I truncus arteriosus, and ventricular septal defect. Both kidneys showed evidence of pelvi-ureteric junction obstruction. The ovaries and fallopian tubes were present with an absent uterus and vagina (Rokitansky sequence). In addition, Dandy-Walker malformation was identified. Microscopically, a single hypoplastic parathyroid gland was noted and there was cystic renal dysplasia. We report the sixth case of the facio-auriculo-vertebral sequence in association with Rokitansky sequence and the first case of this sequence in association with Dandy-Walker malformation. In addition, features of DiGeorge sequence were present.

Abnormalities, Multiple↗