Biomedical subjects

J Stankovich

Publications and source records attributed to J Stankovich.

3 recordsLinked to original sources

PubMed2004

Measuring environmental factors can enhance the search for disease causing genes?

The value of the concurrent measurement of environmental factors in studies aimed at the discovery of disease causing genes has been questioned on the grounds that such an approach fails to increase study power. This report discusses the issue and shows with examples from the recent literature that the examination of a gene disease association within an environmental subgroup can provide enhanced opportunities for detecting gene effects. The concurrent collection of environmental as well as genetic factors in studies of disease aetiology may enhance study informativeness and validity in several ways, including an increase in the power of the study to detect gene disease associations.

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PubMed2002

Investigation of chromosome 2q in osteoarthritis of the hand: no significant linkage in a Tasmanian population.

BACKGROUND: Previous studies have suggested a strong genetic component to osteoarthritis (OA), especially that of the hand, and three linkage studies have suggested the existence of susceptibility loci in disparate regions of chromosome 2q. OBJECTIVE: To examine for linkage to 2q in a Tasmanian population of women and men with familial hand OA. METHODS: Hand OA (distal interphalangeal, carpometacarpal, and Heberden's nodes) was assessed by a combination of hand photographs and radiographs. A non-parametric linkage (NPL) analysis was performed on chromosome 2q of 69 members in 22 families with severe distal interphalangeal joint OA using Genehunter. A quantitative trait linkage analysis of a larger group of 456 members in 68 families was also performed using SOLAR. RESULTS: The maximum non-parametric linkage score was 1.05 (p=0.15) at marker IL1R1, close to the centromere. All components of hand OA scores had significant heritability in this dataset (28%-35%, all p<0.001). Despite this, the quantitative trait analysis (after adjustment for age and, where appropriate, sex) yielded maximum LOD scores of 0.90 for Heberden's nodes (both sexes combined), and 1.19 for carpometacarpal OA score (women only). CONCLUSIONS: These results do not provide confirmation of linkage on chromosome 2q in the larger white population with hand OA. They suggest that there are regional variations in the genetic cause of hand OA and that other loci not on 2q may be important in this disease.

Adult↗

PubMed1999

Interactions between Two Spherical Particles with Nonuniform Surface Potentials: The Linearized Poisson-Boltzmann Theory.

Using the linearized Poisson-Boltzmann theory, electrical double layer interactions are calculated between two nonuniform spherical colloidal particles with mean potential zero. Most results are for the case of surface potentials modeled by a single spherical harmonic and aligned relative to each other. As previously observed for flat surfaces, interactions decay more rapidly as a function of separation between spheres with such periodic, "single-mode" potentials than between spheres with uniform potentials. The Deryaguin approximation for single-mode spheres is tested and calculations are made of the force and torque that particles in a doublet exert on one another. Many of the concepts developed from models of flat plates with periodic aligned surface potentials are shown to be useful in this more general case. Attempts to explain recent differential electrophoresis experiments on the basis of nonuniform double layers fail in that the maximum restraining torques produced under plausible assumptions about the amplitude of nonuniformity are an order of magnitude smaller than those implied by the measurements. The main reason for this is that the torques are too small at the separations characteristic of a secondary minimum. The effect of misalignment of single-mode spheres is assessed by calculating the distribution of interaction energies over a set of relative orientations generated by quasi-random sampling. Finally, a method for generating spheres with "random" surface potentials is devised and potentials of mean force are calculated for pairs of spheres with such surface potentials. Comparison with the single-mode case is kept at a qualitative level, in the absence of detailed knowledge of how realistic such "random" surfaces are. Copyright 1999 Academic Press.

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