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Objective. To determine the tissue specificity of a porcine 127-kd nucleotide pyrophosphohydrolase (NTPPHase) found in vesicles derived from hyaline articular cartilage (ACV).Methods. Homogenates of porcine brain, lung, liver, kidney, urinary bladder, pancreas, spleen, skin, vena cava, marrow, bone (cells), tendon (Achilles), ligament (anterior cruciate), elastic cartilage, meniscus, and hyaline cartilage were analyzed for NTPPHase activity (thymidine monophosphate paranitrophenyl ester substrate) and by Western blot using polyclonal antibodies against 127-kd NTPPHase and against recombinant PC-1, another ecto-NTPPHase.Results. All tissues contained NTPPHase activity; the highest specific activity was found in hyaline articular cartilage, the lowest in brain. ACV-associated 127-kd NTPPHase was expressed in cartilage, ligament, and tendon. PC-1 was also expressed in those tissues and in skin, kidney, bone cells, and (probably) in liver and muscle.Conclusion. The 127-kd NTPPHase appears to be highly specific for articular tissues.Successful pharmacologic control of inorganic pyrophosphate (PPi) production by articular tissues could prevent calcium pyrophosphate dihydrate (CPPD) crystal deposition and its biologic consequences of acute inflammatory attacks and accelerated joint tissue degeneration. This goal has stimulated _.

Objectives-To determine (a) the influence of HIV in developing osteoarticular infections in intravenous drug abusers (IVDAs) and (b) the differences between the clinical features of osteoarticular infections in IVDAs and a control group of non-IVDAs. Methods-A comparative study of the clinical features of osteoarticular infections in all HIV positive and HIV negative IVDAs admitted to the departments of rheumatology and internal medicine during a 10 year period was carried out.

Objective. To characterize the nucleotide pyrophosphohydrolase (NTPPHase) in human serum.Methods. NTPPHase activity and kinetic analysis were performed using thymidine monophosphate paranitrophenyl ester (TMPNP) or "Py-labeled ATP as substrate. Sera were chromatographed (dye column), and peak fractions were analyzed kinetically and by immunoblot using antibodies to 127-kd articular cartilage vesicle (ACV) NTPPHase as well as to PC-1 and to 58 kd, two plasma membrane ecto-NTPPHases. Enzyme activity was measured before and after sample ultracentrifugation.Results. NTPPHase activity was found in all sera tested (2 normal subjects, 9 arthritis patients). Specific activity was increased 9-32-fold after chromatography; 60430% of total activity was recovered in a single peak containing an -100-kd soluble peptide related to the 127-kd ACV enzyme. The apparent K,,, of this peptide (TMPNP) was virtually identical to that of the porcine ACV 127-kd enzyme. No immunoreactivity against PC-1 or 58kd NTPPHase was found.Conclusion. Human serum NTPPHase is derived from 127-kd ACV-related enzyme.

An indirect fluorescent antibody (IFA) technique has been developed for detection of anti-Dermatophilus antibodies in sheep. Sera from 25 bacteriologically confirmed clinically affected sheep and from 10 negative non affected lambs were used. Whole cell antigen from brain heart infusion cultures of D. congolensis was used and all sera were tested in the same way for cross-reactivity against antigens obtained from cultures of Actinomyces viscosus, Micrococcus luteus, Nocardia asteroides, and Corynebacterium pseudotuberculosis. Sera from Dermatophilus-infected sheep gave positive results with D. congolensis antigen and negative results with the antigens from other bacteria. The whole cell antigens employed were simple to prepare and easy to recognise by microscopy. Cross-reactivity was further tested using the D. congolensis culture whole cell antigen and 3 sera from sheep with bacteriologically confirmed natural infections due to Corynebacterium pseudotuberculosis, Actinomyces pyogenes and Nocardia asteroides. None of these sera showed positive reactions. The authors recommend this technique for serological surveys and research on dermatophilosis.