Dennis F. Lawler

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The domestic dog exhibits greater diversity in body size than any other terrestrial vertebrate. We used a strategy that exploits the breed structure of dogs to investigate the genetic basis of size. First, through a genome-wide scan, we identified a major quantitative trait locus (QTL) on chromosome 15 influencing size variation within a single breed.(More)
Long-term restriction of energy intake without malnutrition is a robust intervention that has been shown to prolong life and delay age-related morbidity. A 1H NMR-based metabonomic strategy was used to monitor urinary metabolic profiles throughout the lifetimes of control-fed and diet-restricted dogs. Urinary metabolic trajectories were constructed for each(More)
OBJECTIVE To evaluate the effects of 25% diet restriction on life span of dogs and on markers of aging. DESIGN Paired feeding study. ANIMALS 48 Labrador Retrievers. PROCEDURES Dogs were paired, and 1 dog in each pair was fed 25% less food than its pair-mate from 8 weeks of age until death. Serum biochemical analyses were performed, body condition was(More)
OBJECTIVE To determine prevalence of radiographic evidence of osteoarthritis in 4 diarthrodial joints of dogs with restricted feed intake, compared with dogs without restricted feed intake. DESIGN Paired feeding study. ANIMALS 48 Labrador Retrievers. PROCEDURE Dogs in litters from 7 dams and 2 sires were paired by sex and weight within litters and(More)
In dogs hip joint laxity that can lead to degenerative joint disease (DJD) is frequent and heritable, providing a genetic model for some aspects of the human disease. We have used Portuguese water dogs (PWDs) to identify Quantitative trait loci (QTLs) that regulate laxity in the hip joint. A population of 286 PWDs, each characterized by ca. 500 molecular(More)
While aging studies employing a cross-sectional design have been informative in documenting many age-related alterations in immune function between different age cohorts within a population, longitudinal studies are invaluable for verifying changes at the level of the individual and for defining the precise periods of life during which particular changes(More)
OBJECTIVE To determine the chronology of radiographic signs of canine hip dysplasia (CHD), specifically joint laxity and secondary osteoarthritis (OA). STUDY DESIGN Longitudinal cohort study. ANIMALS Paired littermates, 48 Labrador retrievers. METHODS Conventional, ventrodorsal, hip-extended (HE) radiographs were evaluated yearly for CHD according to(More)
Recent evidence indicates that the cells of the immune system and their large network of secretory products, or cytokines, play an active role in the ovary throughout the oestrous cycle. In the present study, immune cell populations (T and B lymphocytes, macrophages, granulocytes and eosinophils) and expression of major histocompatibility complex (MHC)(More)
OBJECTIVE To describe effects of lifetime food restriction on causes of death and the association between body-mass characteristics and time of death in dogs. DESIGN Paired-feeding study. ANIMALS 48 dogs from 7 litters. PROCEDURES Dogs were paired, and 1 dog in each pair was fed 25% less food than its pair mate from 8 weeks of age until death.(More)