PubMed Health⌕ Search

Biomedical subjects

G Lust

Publications and source records attributed to G Lust.

At least 109 records · Page 6Linked to original sources
PubMed1980

Radionuclide joint imaging: an ancillary technique in the diagnosis of canine hip dysplasia.

Radionuclide joint imaging has been adapted for use in the diagnosis of canine hip dysplasia. Studies were done on 29 growing Labrador Retriever pups between 3 months and 1.5 years of age and on two adult dogs. Initally, pelvic radiographs and joint images were done on pups 12 to 16 weeks of age and were repeated at 2-week intervals thereafter. 99mTechnetium methylene diphosphonate (99mTcMDP), an osteotrphic agent, was the radiopharmaceutical used for all imaging studies. Inteference due to 99mTcMDP accumulation in the urinary bladder was avoided by static abdominal pressure. In 19 of the 21 dogs identified as abnormal by pelvic radiography, a similar diagnosis based on joint imaging was made for a true positive ratio of 0.90. Eight of ten dogs were identified as normal by means of both procedures, for a true negative ratio of 0.80. The overall accuracy was 0.87. Joint imaging was thus shown to be of similar value as pelvic radiography in the diagnosis of hip dysplasia. Joint images, however, displayed information on bone metabolic activity that could not be determined by pelvic radiography.

Animals↗
PubMed1980

Intra-articular volume and hip joint instability in dogs with hip dysplasia.

UNLABELLED: The nature of the instability of the hip joint in dogs with dysplasia of the hip was investigated. In the experimental canine model, instability of the joint, as shown by subluxation of the femoral head on a roentgenogram, was accompanied by an increase in the volume of the synovial fluid and of the ligamentum teres and, therefore, an increase in the intra-articular volume. Injection of a buffered solution of hyaluronic acid into non-subluxated hip joints in situ increased subluxation, whereas withdrawal of synovial fluid from one joint with severe subluxation reduced the degree of subluxation. The withdrawal of varying amounts of synovial fluid from excised but intact joints resulted in a decrease in the lateral displacement of the femoral heads. Injection of the hyaluronic acid solution into excised joints resulted in increased lateral displacement of the femoral heads. The results suggest that the joint instability associated with canine hip dysplasia is related to increased intra-articular volume. CLINICAL RELEVANCE: Instability of the hip joint (abnormal laxity) is a feature of hip dysplasia in dogs and congenital dislocation of the hip in children. The canine disease can provide a valuable model in which to examine the pathogenesis of hip instability. The model may be useful to test prophylactic procedures to prevent joint instability and thus ameliorate disease.

Animals↗
PubMed1979

Accumulation of procollagen in the degenerative articular cartilage of dogs with osteoarthritis.

Collagen metabolism was studied in degenerative articular cartilage of dogs with spontaneous, early onset osteoarthritis. A fraction of collagen which represented about 1.5% of the total was extracted from cartilage samples with dilute phosphate buffer (pH 7.4) containing 0.2% sodium dodecyl sulfate. Agarose gel filtration in the presence of sodium dodecyl sulfate revealed that extracts of degenerative cartilage had about 24% procollagen whereas extracts of normal samples had only 3%. The isolated procollagen fraction was rechromatographed on agarose columns in the presence of mercaptoethanol. This resulted in the identification of a collagen species which migrated between marker beta and alpha collagen chains. The molecular weight of this collagen was estimated to be 150,000. Based on incorporation of [14C]proline, its ratio of hydroxy[14C]proline to total 14C was 0.32. Procollagen was not found after limited pepsin digestion (pH 3, 4 degrees C, 16 h) of degenerative cartilage samples. Since the total collagen content (microgram hydroxyproline/mg cartilage), hydroxy-[14C]proline/mg cartilage, specific radioactivity of hydroxyproline in the extractable collagen fraction were similar for normal and degenerative cartilage we propose that procollagen accumulated in the degenerative cartilage due to a partial defect in conversion of procollagen to collagen.

Animals↗
PubMed1978

An improved procedure for genetic selection against hip dysplasia in dogs.

Rapid weight gain can educe hip dysplasia of dogs with normal hip joints. It is proposed that progeny whose parents have "excellent genotypes" would not be susceptible to this stress and would develop normal hip joints. The method for reducing the incidence of hip dysplasia in dogs would be to use stress to identify carriers (parents) and potential carriers (progeny), and select for breeding only dogs with proved genotypic value and those progeny with the best hip joint conformation.

Animals↗
PubMed1976

A rapid, enzymatic assay for measurement of inorganic pyrophosphate in biological samples.

An enzymatic assay for measurement of inorganic pyrophosphate (PPi) in biological samples is described using the UDPG pyrophosphorylase reaction and coupling it with three other enzymes in a system of phosphorylation and double reduction to form NADPH, which is measured fluorometrically. The method is specific for PPi in the presence of inorganic orthophosphate and can be used on small volumes of deproteinized ultrafiltrates of fluids or cell extracts. The assay was used here to determine the concentration of PPi in human plasma and serum, and the intracellular content of PPi in human skin fibroblasts, chondrocytes, and red blood cells. The mean PPi concentration of plasma was found to be 2.72 +/- 0.14 muM (mumo/l +/- S.E.M.); for serum it was 6.09 +/- 0.36 muM. The range (95% confidence limits) was 2.14-3.30 muM for plasma and 4.62-7.51 muM for serum. The average intracellular PPi content (pmoles PPi per 10(6) cells +/- S.E.M.) was as follows: (a) skin fibroblasts, 332 +/- 66; (b) articular chondrocytes, 655 +/- 46; red blood cells, 1.74 +/- 0.28.

Animals↗
PubMed1975

Ultrastructure of canine articular cartilage: comparison of normal and degenerative (osteoarthritic) hip joints.

Normal canine hip cartilage was compared with cartilage from the degenerative lesions found in young dogs with canine hip dysplasia. The upper 0.5 mm of normal cartilage was characterized. Four distinct layers or zones were found: a layer of fine fibrous material covering the surface, a layer (surface layer) of small (32 nm diameter or less) collagen fibrils tightly packed in bundles and oriented parallel to the surface, a layer (upper layer) or less tightly packed collagen fibrils oriented mostly parallel to the surface with about 33% of the fibrils 64 nm or more, and a layer (intermediate layer) of randomly oriented fibrils with more than 50% of the fibrils 64 nm or larger. Fibril density was high in the surface layer and decreased with depth into the cartilage. In a moderately advanced lesion of degenerative cartilage, there was a layer of amorphous material over the surface. The tightly packed surface layer of small fibrils was absent. The surface itself was uneven and fissued. At depths from the surface comparable to the upper and the intermediate layers in normal cartilage, the proportion of large fibrils was less than in normal cartilage. The overall density of fibrils in degenerative cartilage increased with depth into the tissue. Cells flattened parallel to the surface, with relatively large nuclei, were found in the upper layer of normal cartilage. Cells in the intermediate layers were larger and round. The oblong cells of the upper layer of normal cartilage were not found in any layer of degenerative cartilage. Differences between cells in other layers of normal and degenerative cartilages were minimal. A model for the arrangement of chondrocytes and collagen fibrils for normal and degenerative cartilage was proposed. Ultrastructural changes in degenerative cartilage were prominent in the upper 0.5 mm of cartilage. These changes were changes in the number of collagen fibrils/mum-2 and a change from a characteristic pattern of collagen fibril diameters and orientation found in normal tissue.

Animals↗