Effects of the garlic components diallyl sulfide and diallyl disulfide on arylamine N-acetyltransferase activity in human colon tumour cells

Diallyl sulfide (DAS) and diallyl disulfide (DADS), major components of garlic, were used to determine inhibition of arylamine N-acetyltransferase (NAT) activity in a human colon tumour (adenocarcinoma) cell line. Two assay systems were performed, one with cellular cytosols (9000g supernatant), the other with intact bacterial cell suspensions. The NAT activity in a human colon tumour cell line was inhibited by DAS and DADS in a dose-dependent manner in both system: that is, the greater the concentration of DAS and DADS in the reaction, the greater the inhibition of NAT activities in both systems. The data also indicated that DAS and DADS decrease the apparent values of Km and Vmax of NAT enzymes from human colon tumour cells in both systems examined. This is the first report to demonstrate that garlic components do affect human colon tumour cell NAT activity.     

Reliability analysis of a k-out-of-N:G redundant system in the presence of chance with multiple critical errors

A reliability analysis of a k-out-of-N: G redundant system with multiple critical errors and r repair facilities in the presence of chance, is dealt with in this paper. The system is in a failed state when k units have failed or one of any multiple critical errors has occurred. Failed system repair times are arbitrarily distributed. The formulae for reliability function in terms of a Laplace transform, steady-state availability and mean time to failure are derived.     

Induction of T-cell hyporesponsiveness by intrahepatic modulation of donor antigen-presenting cells

In this study, we examined the ability of varying populations of donor cells from B6 mice to induce hyporesponsiveness in T lymphocytes from C3H mice in vitro and in vivo. Small, resting B lymphocytes were inefficient stimulators of T-lymphocyte proliferation compared to splenic mononuclear cells (SMNC) and lipopolysaccharide (LPS)-induced B-cell blasts in vitro (P < 0.05). Pretreatment of SMNC with anti-B7-1 or anti-intracellular adhesion molecule-1 (ICAM-1) monoclonal antibodies (mAb) similarly resulted in inefficient stimulation of T-cell proliferation in vitro (P < 0.05). However, in vivo, only intrahepatic, but not intravenous, injection of donor cells into C3H mice resulted in decreased T-lymphocyte proliferation in response to restimulation by alloantigen. This effect was most pronounced following intrahepatic injection of resting B lymphocytes or SMNC pretreated with anti-ICAM-1 mAb compared to uninjected or intravenously injected mice (P < 0.05). The hyporesponsiveness was associated with an increased production of interleukin-4 (IL-4) by the responder T lymphocytes and correlated with enhanced skin allograft survival. These data demonstrate that intrahepatic injection of donor-derived cells induces T-lymphocyte hyporesponsiveness. The mechanism appears to be modulated by an ICAM-1-mediated signal resulting in expansion of an IL-4-producing T-lymphocyte population.     

Identification and characterization of a novel human aldose reductase-like gene

We have identified a novel human protein that is highly homologous to aldose reductase (AR). This protein, which we called ARL-1, consists of 316 amino acids, the same size as AR, and its amino acid sequence is 71% identical to that of AR. It is more closely related to the AR-like proteins such as mouse vas deferens protein, fibroblast growth factor-regulated protein, and Chinese hamster ovary reductase, with 81, 82, and 83%, respectively, of its amino acid sequence identical to the amino acid sequence of these proteins. The cDNA of ARL-1 was expressed in Escherichia coli to obtain recombinant protein for characterization of its enzymatic activities. For comparison, the cDNA of human AR was also expressed in E. coli and analyzed in parallel. These two enzymes differ in their pH optima and salt requirement, but they act on a similar spectrum of substrates. Similar to AR, ARL-1 can efficiently reduce aliphatic and aromatic aldehydes, and it is less active on hexoses. While AR mRNA is found in most tissues studied, ARL-1 is primarily expressed in the small intestines and in the colon, with a low level of its mRNA in the liver. The ability of ARL-1 to reduce various aldehydes and the locations of expression of this gene suggest that it may be responsible for detoxification of reactive aldehydes in the digested food before the nutrients are passed on to other organs. Interestingly, ARL-1 and AR are overexpressed in some liver cancers, but it is not clear if they contribute to the pathogenesis of this disease.     

Managing the US Navy's first OO digital mapping project

In the late 1980s the Defense Mapping Agency began converting their paper maps into digital format. A military standard known as Vector Product Format emerged as the format for storing digital vector data. The VPF relational data model, however, has problems representing complex spatial data. In 1991, the US Navy, a DMA database user, began investigating how object technology could improve its digital maps. This research led to the development of the Object Vector Product Format, an object-oriented approach to viewing and editing digital maps and charts. By combining multiple relational databases into a single OO database, OVPF offers users such key advantages as the ability to immediately update and modify the content of the original data. Over the course of developing OVPF we have also learned some valuable lessons about managing OO projects. Our experiences have given us insight into some important risk-management techniques, including how to manage the expectations of decision-makers and sponsors and how to implement effective training methods. Managing the OVPF project was much more rewarding than most due to the greatly increased productivity offered by an OO approach     

Microstructure and properties of Cu-C pseudoalloy films prepared by sputter deposition

The microstructure and properties of Cu-C pseudoalloy films prepared by R.F. magnetron sputtering have been investigated. As Cu and C are mutually immiscible, nonequilibrium supersaturated solid solutions of C in Cu with nanocrystalline microstructures were observed in as-deposited films. Upon heating of the films, three major transition events took place. Recovery occurred at ∼280 to 300 °C, while at ∼400 °C, crystallites started to growth and coalescence, due to the release of strain energies stored during deposition. Annealing at above 600 °C led to the occurrence of grain growth and altered the microstructure considerably. Although attempts have been made in this study, a possible annealing-induced phase separation could not be unambiguously identified. Yet, the fact of low twin densities and fine grain structures observed in the annealed films suggests that the extensive grain growth was impeded by the presence of carbon. Resistivity and hardness properties correlated well with the film microstructure and were governed by the impurity effect of carbon. Low-carbon Cu-C films yielded relatively low resistivity, attributable to the improved film microstructure. Hardness results indicated the strengthening of films was mainly due to fine structure, presence of carbon, and grain refinement by annealing twins.     

Antimicrobial susceptibilities of Porphyromonas gingivalis, Prevotella intermedia, and Prevotella nigrescens spp. isolated in Spain

The susceptibilities of 143 Porphyromonas gingivalis, Prevotella intermedia, and Prevotella nigrescens isolates to 18 antimicrobial agents were tested. All P. gingivalis isolates were susceptible. In contrast, some Prevotella spp. (17%) were resistant to beta-lactams, erythromycin, clindamycin, or tetracycline and carried resistance genes, ermF or tetQ, or beta-lactamases.     

Coded 64-CAP ADSL in an impulse-noise environment-modeling ofimpulse noise and first simulation results

This paper presents the performance of various coding schemes for the asymmetrical digital subscriber line (ADSL) in an impulse-noise environment. Impulse noise is considered to be one of the most damaging impairments in the ADSL, in which compressed video signals are delivered to residential customers. The impulse noise used in this study was measured and collected in German telephone networks. Based on this measurement and the corresponding statistical modeling, a simulation model for impulse noise is proposed and its properties are outlined. The coding schemes considered here utilize burst-error correcting Reed-Solomon codes and/or random error correcting trellis codes as well as symbol interleaving between the two codes. It has been found through computer simulations that a proper concatenation of the two codes could increase the immunity against impulse noise compared to an uncoded scheme. Specifically, a concatenated code, using a 2-dimensional 8-state trellis code and a 4-error-correcting Reed-Solomon code with an interleaving depth of 18 symbols, was able to eliminate all the errors caused by the impulse noise used in the study. It has also been found that the trellis codes are not very effective against impulse noise, unless they are used in conjunction with Reed-Solomon codes and a proper symbol interleaving. Performance results of other coding configurations using Reed-Solomon codes with different error-correcting capabilities are also presented. In addition, we also show the performance results when simple array codes are used instead of the Reed-Solomon codes