Growth promoting peptides in osteoarthritis and diffuse idiopathic skeletal hyperostosis--insulin, insulin-like growth factor-I, growth hormone

OBJECTIVE: To investigate growth factors influencing bone and cartilage in patients with diffuse idiopathic skeletal hyperostosis (DISH). METHODS: Standard radioimmunoassays (INCSTAR, Stillwater, MN) quantified serum levels of insulin, insulin-like growth factor-I (IGF-I) and growth hormone (GH) in patients with DISH, in patients with osteoarthritis (OA) and in controls. Patients with DISH with comorbidity with obesity, hypertension, diabetes and coronary artery disease, also were studied. RESULTS: Patients with DISH demonstrated normal IGF-I levels; patients with OA had reduced IGF-I levels. Subjects with DISH or OA had elevated insulin and GH values. Patients with DISH with comorbidity had changes in growth factors similar to those found in patients with DISH only. There is frequent association of DISH with obesity, hypertension, coronary artery disease and diabetes mellitus suggesting that these associations are not random. CONCLUSION: Specific associations of skeletal abnormalities with clinical features in which skeletal change and clinical features combine with disturbances of insulin, IGF-I and GH exist in DISH that are distinct from OA. DISH is considered a multisystemic hormonal disorder with protean presentations.     

Remote heat sink concept for high power heat rejection

This paper addresses heat rejection concepts intended to reject 100 W (or more) from the CPU of a desktop computer or server. A high-performance, air-cooled thermo-syphon heat rejection system is described that meets the goal. This concept is believed to represent the highest performance that has been reported for an air-cooled heat rejection system. A working fluid is boiled in a small chamber mounted on the CPU, and the vapor is condensed in the tubes of the remotely located air-cooled condenser. The air-cooled heat exchanger provides much higher performance than is obtainable with conventional "round-tube" technology. The boiling design is compared with other systems that have been proposed, e.g., liquid or two-phase cooling in micro-channels, and is shown to provide better performance. The heat exchange technology may also be applied to refrigerated cooling.     

Modelling the energy cost of a fully operational wireless sensor network

Several applications have been proposed for wireless sensor networks, including habitat monitoring, structural health monitoring, pipeline monitoring, precision agriculture, active volcano monitoring, and many more. The energy consumption of these applications is a critical feasibility metric that defines the scope and usefulness of wireless sensor networks. This paper provides a comprehensive energy model for a fully functional wireless sensor network. While the model uses toxic gas detection in oil refineries as an example application, it can easily be generalized. The model provides a sufficient insight about the energy demand of the existing or proposed communication protocols.     

Software agent-based directed diffusion in wireless sensor network

In an environment where node density is massive, placement is heterogeneous and redundant sensory traffic is produced; limited network resources such as bandwidth and energy are hastily consumed by individual sensor nodes. Equipped with only a limited battery power supply, this minimizes the lifetime of these sensor nodes. At the network layer, many researchers have tackled this issue by proposing several energy efficient routing schemes. All these schemes tend to save energy by elevating redundant data traffic via in-network processing and choosing empirically good and shortest routing paths for transfer of sensory data to a central location (sink) for further, application-specific processing. Seldom has an attempt been made to reduce network traffic by moving the application-specific code to the source nodes. We unmitigated our efforts to augment the node lifetime within a sensor network by introducing mobile agents. These mobile agents can be used to greatly reduce communication costs, especially over low bandwidth links, by moving the processing function to the data rather than bringing the data to a central processor. Toward this end, we propose an agent-based directed diffusion approach to increase sensor node efficiency and we present the experimental results.     

Aromatic hydrocarbon receptor polymorphism: development of new methods to correlate genotype with phenotype

BACKGROUND: Non-steroidal anti-inflammatory drugs can reduce the risk of colorectal cancer. Reportedly, mRNA expression of cyclooxygenase-2 (COX-2) is elevated in human colorectal cancers compared with accompanying normal mucosa. The present study was undertaken to establish a simple analytical procedure to quantify COX-2 expression levels and to characterize COX-2 expression levels in human colorectal cancers, adenomas and hyperplastic polyps. METHODS: The combination of PCR using common primers designed in the highly conserved regions and fluorescence-based single-strand conformation polymorphism (F-SSCP) analysis of the products is used for quantitative determination of the proportions of COX-2 mRNA in human colorectal cancers, adenomas, hyperplastic polyps and accompanying normal mucosa. RESULTS: The present F-SSCP analysis was a simple and powerful method for quantitative determination of the proportions of COX-2 mRNA. The proportion of COX-2 mRNA was higher in cancer tissues than in accompanying normal mucosa in 46 of the 50 cancers. There was no significant correlation between the increase of the COX-2 proportion and tumor location or stages. The enhanced COX-2 expression was also observed in colorectal adenomas. On the other hand, the proportion of COX-2 mRNA in hyperplastic polyps was not significantly different from that in normal mucosa. CONCLUSIONS: The proportion of COX-2 to COX-1 expression was elevated in most human colorectal cancers and adenomas, but not in hyperplastic polyps. Therefore, the increased proportion of COX-2 expression might be an early event in the carcinogenesis of colorectal cancer.     

Hypoxic activation of nuclear factor-kappa B is mediated by a Ras and Raf signaling pathway and does not involve MAP kinase (ERK1 or ERK2)

We have previously shown that hypoxia causes the activation of nuclear factor-kappa B (NF-kappa B), and the phosphorylation of its inhibitory subunit, I kappa B alpha, on tyrosine residues. With the use of dominant negative mutants of Ha-Ras and Raf-1, we investigated some of the early signaling events leading to the activation of NF-kappa B by hypoxia. Both dominant negative alleles of Ha-Ras and Raf-1 inhibited NF-kappa B induction by hypoxia, suggesting that the hypoxia-induced pathway of NF-kappa B induction is dependent on Ras and Raf-1 kinase activity. Furthermore, although conditions of low oxygen can also activate mitogen-activated protein kinases (ERK1 and ERK2), these kinases do not appear to be involved in regulating NF-kappa B by low oxygen conditions, as dominant negative mutants of mitogen-activated protein kinase do not inhibit NF-kappa B activation by hypoxia. Since Ras and Raf-1 have been previously shown to work downstream from membrane-associated tyrosine kinases such as Src, we determined if the Src membrane-associated kinase was also activated by low oxygen conditions. We detected an increase in Src proto-oncogene activity within 15-30 min of cellular exposure to hypoxia. We postulate that Src activation by hypoxia may be one of the earliest events that precedes Ras activation in the signaling cascade which ultimately leads to the phosphorylation and dissociation of the inhibitory subunit of NF-kappa B, I kappa B alpha.