Biomedical subjects

Thomas Bittner

Publications and source records attributed to Thomas Bittner.

4 recordsLinked to original sources

PubMed2005

Biomedical ontologies: what part-of is and isn't.

Mereological relations such as part-of and its inverse has-part are fundamental to the description of the structure of living organisms. Whereas classical mereology focuses on individual entities, mereological relations in biomedical ontologies are generally asserted between classes of individuals. In general, this practice leaves some basic issues unanswered: type constraints of mereological relations, e.g., concerning artifacts and biological entities, the relation between parthood and time, inferred parts and wholes as well as a delimitation of parthood against spatial inclusion. Furthermore, mereological relations can be asserted not only between physical objects but also between biological processes and medical procedures. We analyze these ambiguities and make suggestions for a standardization of mereological relations in biomedical ontologies.

Anatomy↗

PubMed2005

Granularity, scale and collectivity: when size does and does not matter.

Bridging levels of "granularity" and "scale" are frequently cited as key problems for biomedical informatics. However, detailed accounts of what is meant by these terms are sparse in the literature. We argue for distinguishing two notions: "size range," which deals with physical size, and "collectivity," which deals with aggregations of individuals into collections, which have emergent properties and effects. We further distinguish these notions from "specialisation," "degree of detail," "density," and "connectivity." We argue that the notion of "collectivity"--molecules in water, cells in tissues, people in crowds, stars in galaxies--has been neglected but is a key to representing biological notions, that it is a pervasive notion across size ranges--micro, macro, cosmological, etc.--and that it provides an account of a number of troublesome issues including the most important cases of when the biomedical notion of parthood is, or is not, best represented by a transitive relation. Although examples are taken from biomedicine, we believe these notions to have wider application.

Animals↗

PubMed2005

A formal theory for spatial representation and reasoning in biomedical ontologies.

OBJECTIVE: The objective of this paper is to demonstrate how a formal spatial theory can be used as an important tool for disambiguating the spatial information embodied in biomedical ontologies and for enhancing their automatic reasoning capabilities. METHOD AND MATERIALS: This paper presents a formal theory of parthood and location relations among individuals, called Basic Inclusion Theory (BIT). Since biomedical ontologies are comprised of assertions about classes of individuals (rather than assertions about individuals), we define parthood and location relations among classes in the extended theory Basic Inclusion Theory for Classes (BIT+Cl). We then demonstrate the usefulness of this formal theory for making the logical structure of spatial information more precise in two ontologies concerned with human anatomy: the Foundational Model of Anatomy (FMA) and GALEN. RESULTS: We find that in both the FMA and GALEN, class-level spatial relations with different logical properties are not always explicitly distinguished. As a result, the spatial information included in these biomedical ontologies is often ambiguous and the possibilities for implementing consistent automatic reasoning within or across ontologies are limited. CONCLUSION: Precise formal characterizations of all spatial relations assumed by a biomedical ontology are necessary to ensure that the information embodied in the ontology can be fully and coherently utilized in a computational environment. This paper can be seen as an important beginning step toward achieving this goal, but much more work along these lines is required.

Anatomy↗

PubMed2004

New real-time PCR-based method for in vitro susceptibility testing of Anaplasma phagocytophilum against antimicrobial agents.

Up to now, only a few isolates of Anaplasma phagocytophilum have been tested for their susceptibility against a small number of antimicrobial agents. In addition, as with other fastidious or intracellular bacteria, the test methods are laborious and neither minimal inhibitory concentration (MIC) definitions, nor the test conditions and the inocula are standardised to date. A new 16S-rDNA-based real-time PCR assay has been developed and used under standardised conditions to analyse the activity of seven antimicrobial agents against two A. phagocytophilum isolates. After 72 h incubation, MICs were determined by software-assisted calculation of bacterial growth in samples and controls from semi-quantitative PCR results. In our study, the rank order of potency on a mg/l basis for the antimicrobial agents with enhanced in vitro activity against A. phagocytophilum was moxifloxacin (MIC: < or = 0.03 mg/l) > doxycycline (MIC: < or = 0.125 mg/l) > ciprofloxacin (MIC: 0.125 mg/l). Gentamicin, ampicillin, azithromycin and cethromycin showed no activity against the isolates tested in this investigation. Our new 16S-rDNA-PCR-based microdilution test system was shown to be sensitive, reproducible and reliable. The assay is capable of testing larger numbers of isolates and antimicrobial agents under standardised and very precise test conditions and may therefore offer a competent technical solution of the difficulties known to be associated with in vitro testing of other bacterial pathogens that grow intracellularly, such as chlamydia or rickettsia.

Ampicillin↗