The human P2Y6 receptor (hP2Y6) is a member of the G protein-coupled pyrimidinergic P2 receptor family that responds specifically to the extracellular nucleotide uridine diphosphate (UDP). Recently, the hP2Y6 receptor has been reported to mediate monocyte IL-8 production in response to UDP or lipopolysaccharide (LPS), but the role of hP2Y6 in regulating other pro-inflammatory cytokines or mediators is largely unknown. We demonstrate here that UDP specifically induces soluble TNF-alpha and IL-8 production in a promonocytic U937 cell line stably transfected with hP2Y6. However, we did not detect IL-1alpha, IL-1beta, IL-6, IL-10, IL-18, and PGE2 in the conditioned media from the same cell line. These results distinguish UDP/P2Y6 signaling from LPS signaling. Interestingly, UDP induces the production of IL-8, but not TNF-alpha, in human astrocytoma 1321N1 cell lines stably transfected with hP2Y6. Therefore, the immune effect of UDP/P2Y6 signaling on the production of proinflammatory cytokines is selective and dependent on cell types. We further identify that UDP can also induce the production of proinflammatory chemokines MCP-1 and IP-10 in hP2Y6 transfected promonocytic U937 cell lines, but not astrocytoma 1321N1 cell lines stably transfected with hP2Y6. From the Taqman analysis, UDP stimulation significantly upregulates the mRNA levels of IL-8, IP-10, and IL-1beta, but not TNF-alpha. Taken together, these new findings expand the pro-inflammatory biology of UDP mediated by the P2Y6 receptor.

Thread migration is established as a mechanism for achieving dynamic load sharing and data locality. However, migration has not been used with fine-grained parallelism on workstation clusters due to the relatively high overheads associated with thread and messaging packages. This paper describes a portable, high performance thread migration system, implemented with user level threads and active messages. The thread system supports an extensible event mechanism which permits an efficient interface between the thread and active message system. Migration is supported by user level primitives; applications may implement different migration policies on top of the migration interface provided. The system runs on a cluster of SMPs and the performance obtained is orders of magnitude better than other reported measurements.

Thread migration is established as a mechanism for achieving dynamic load sharing. However, fine-grained migration has not been used due to the high thread and messaging overheads. This paper describes a fine-grained thread migration system whose extensible event mechanism permits an efficient interface between threads and communications without compromising the modularity and performance of either. Migration is supported by user level primitives based on which applications may implement different migration policies. The system is portable and can be used directly or serve as a compilation target for parallel languages. The system runs on a cluster of SMPs and observed performance is orders of magnitude better than other reported measurements.

Thread migration is established as a mechanism for achieving dynamic load sharing and data lo- cality. However, migration has not been used with fine-grained parallelism due to the relatively high overheads associated with thread and messaging packages. This paper describes a high per- formance thread migration system for fine-grained parallelism, implemented with user level threads and user level messages. The thread system supports an extensible event mechanism which permits an efficient interface between the thread and messaging systems without compro- mising the modularity of either . Migration is supported by user level primitives; applications may implement different migration policies on top of the migration interface provided. The sys- tem is portable and can be used directly by application and library writers or serve as a compila- tion target for parallel programming languages. Detailed performance metrics are pr esented to evaluate the system. The system runs on a cluster of SMPs and the performance obtained is or- ders of magnitude better than other reported measurements2.

Consistency of objects in a concurrent computing environment is usually ensured by serializing all incoming method calls. However, for high performance parallel computing intra-object parallelism, i.e. concurrent execution of methods on an object, is desirable. Currently, languages supporting intra-object parallelism are based on object models that leave it to the programmer to ensure consistency. We present an object model, that ensures object consistency while supporting intra-object concurrency thereby offering both safety and efficiency. The description starts with a simple and safe, but inefficient model and gradually increases the sophistication by introducing features for expressiveness and greater efficiency while maintaining safety. Based on this model we define extensions for guarded suspension and data parallel programming. The model and the extensions are defined as a language proposal for a new version of Sather, Sather 2. The proposal is based on Sather 1.1, but replaces the parallel extensions of this version.

Abstract

This chapter discusses the methods of preparation of mitochondrial amine oxidase (Monoamine Oxidase) (Beef Liver). The enzyme is assayed by the same procedure already described for beef plasma amine oxidase. The unit of enzyme and the specific activity are also defined. For assaying the activity of the enzyme in mitochondria, the substrate kynuramine may be used. About 13-20 pounds of fresh liver are obtained at the abattoir. The membrane and veins are removed, and the liver was diced into small pieces. When the purified enzyme was rechromatographed on DEAE-cellulose, hydroxylapatite or Sephadex G-200, a single component was observed. The ultracentrifuge pattern disclosed a single component but the peak was slightly skewed, indicating a possible association-dissociation of the enzyme. The enzyme is inhibited by a large number of drugs. It is also inhibited by a number of known metal chelating agents such as cuprizone, neocuproine, 8-hydroxquinoline, sodium diethyldithiocarbamate, o-phenanthroline and α,α-bipyridyl.

By modifying a previously published purification procedure, three fractions of liver mitochondrial amine oxidase were isolated in sufficient yields to characterize them.

Beef liver mitochondrial amine oxidase components 1 and 2 contain about 28 and 86 sulfhydryl groups per mole of enzyme or 7 sulfhydryl groups per 100,000 g of protein. The rate of reaction of p-chloromercuribenzoate with the enzyme was complete in about 30 min and 8 m urea had no effect on the rate of reaction. After reaction of all the sulfhydryl groups with p-chloromercuribenzoate, the enzyme was not completely inhibited and removal of the excess sulfhydryl reagent led to reactivation of the enzyme. At higher p-chloromercuribenzoate concentrations, the enzyme was inhibited noncompetitively. Iodoacetic acid and iodoacetamide did not inhibit the enzyme appreciably even at a concentration of 1 × 10−3m. Certain heavy metal salts inhibited the enzyme noncompetitively. The sulfhydryl groups probably are required for conformational stability rather than being required for catalysis.

Consistency of objects in a concurrent computing environment is usually ensured by serializing all incom- ing method calls. However, for high performance parallel computing intra-object parallelism, i.e. concur- rent execution of methods on an object, is desirable. Currently, languages supporting intra-object parallelism are based on object models that leave it to the programmer to ensure consistency. We present an object model, that ensures object consistency while supporting intra-object concurrency thereby offering both safety and efficiency. The description starts with a simple and safe, but inefficient mod- el and gradually increases the sophistication by introducing features for expressiveness and greater efficien- cy while maintaining safety. Based on this model we define extensions for guarded suspension and data parallel programming. The mod- el and the extensions are defined as a language proposal for a new version of Sather, Sather 2. The proposal is based on Sather 1.1, but replaces the parallel extensions of this version.