Thomas O'Brien

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Recent in vitro studies have shown that the periventricular subependymal zone (SEZ) of the rodent brain is capable of de novo generation of neurons and glia. There is less information available on neurogenesis in the adult human brain, and no study has shown the clonal generation of neurons and glia from in vitro-generated "neurospheres." Here we describe(More)
Desmoglein 2 (Dsg2), a component of the desmosomal cell-cell adhesion structure, has been linked to invasion and metastasis in squamous cell carcinomas. However, it is unknown whether--and if so how--Dsg2 contributes to the malignant phenotype of keratinocytes. In this study, we addressed the consequences of Dsg2 overexpression under control of the(More)
OBJECTIVE To describe the neuropathologic findings in four cases of meningeal melanocytoma, a rare benign melanocytic tumor of the central nervous system. DESIGN Retrospective analysis of surgical pathology and autopsy material. RESULTS Grossly, all four tumors were well-circumscribed pigmented lesions, and three of four were attached to dura.(More)
The global problem of antimicrobial resistance is particularly pressing in developing countries, where the infectious disease burden is high and cost constraints prevent the widespread application of newer, more expensive agents. Gastrointestinal, respiratory, sexually transmitted, and nosocomial infections are leading causes of disease and death in the(More)
This paper focuses on transient boundaries of glia and glycoconjugates during development of the mouse central nervous system (CNS). Lectin-bound glycoconjugates, glial fibrillary acidic protein, and the J1/tenascin glycoprotein are distributed coextensively within boundaries around developing substructural arrangements (e.g., developing nuclei, and at a(More)
BACKGROUND AND METHODS The healthy members of a community represent its largest reservoir of bacteria resistant to antimicrobial agents. We compared the resistance to eight agents of Escherichia coli in stool samples from untreated, healthy children in cities on three continents. RESULTS When screened by a selective method that detected 1 resistant colony(More)
The growing threat from resistant organisms calls for concerted action to prevent the emergence of new resistant strains and the spread of existing ones. Developing countries have experienced unfavourable trends in resistance-as detailed in part I, published last month--and implementation of many of the containment strategies recommended by WHO is(More)
Deoxyribonucleic acid of cells undergoing apoptosis is cleaved by a calcium-dependent endonuclease into oligonucleosomal-sized fragments. These fragments can be labeled using the enzyme terminal deoxynucleotidyl transferase so that the cells can be visualized immunohistochemically. Few investigators have evaluated this method in disease processes of the(More)
Tenascin is an extracellular matrix glycoprotein expressed during both normal development and neoplastic growth in both neural and nonneural tissues. During development of the central nervous system (CNS), tenascin is synthesized by glial cells, in particular by immature astrocytes, and is concentrated in transient boundaries around emerging groups of(More)