BT之后是电驴——网际快车3．0电驴功能实测

我们知道,BT下载的优点是下载速度快、资源分布广、对服务器造成的负担较小,但缺点是每一个BT资源都有时效性.例如:两个月前的BT资源,现在多半是无效的,也就是通常说的"没种子了".而电驴(eMule)则不然,它的特点就是可使用多个途径搜索下载的资料源.由ED2K、来源交换、Kad共同组成一个可靠的网络结构.虽然速度上可能不及BT,但可以搜索得到更多的资源(包括一些N年前的东东).快车在其3.0版中加入对电驴的支持,无疑又将其可用性提高了一大截.至此,快车下载软件可以支持BT、eMule、FTP、HTTP等绝大部分下载方式.     

Immunization of bovines with an aspartic proteinase precursor isolated from Boophilus microplus eggs

The capacity of the Boophilus Yolk pro-Cathepsin (BYC) to induce a protective immune response in cattle against Boophilus microplus infestation was tested by vaccination experiments and by inoculation of monoclonal antibody (MAb) against BYC into fully engorged tick females. In immunization experiments the measurement of various biological parameters demonstrated a partial protection against B. microplus. A continuous decrease in the levels of specific antibodies was observed over 11 months when six bovines were maintained in field conditions. The inoculation of the MAb into tick females produced a dose-dependent decrease in oviposition and survival of the ectoparasite compared to the control.     

Isolation of a bioactive Ca(2+)-mobilizing complex lipid from bovine vitreous body

We have been undertaking the gene therapy for a 6 year-old boy with ADA deficiency and performed 11 cycles of the infusion of the peripheral T cells transduced with retroviral vector LASN since August 8th 1995. The percentage of the peripheral blood lymphocytes carrying the transduced ADA gene has remained stable at 10% to 20% since the 4th infusion. ADA enzyme activity in his circulating T cells increased to levels comparable to 1/3 of a heterozygous carrier individual and was associated with increased T lymphocytes counts and improvement in both humoral and cellular immune function. The results obtained in this clinical study support the usefulness of T lymphocyte-directed gene transfer in the treatment of ADA deficiency.     

Toxicity of inhaled 91YCl3 in dogs

Few systematic studies have been devoted to investigating the role of Ca2+ as an intracellular messenger in prokaryotes. Here we report an investigation on the potential involvement of Ca2+ in signalling in Bacillus subtilis, a Gram-positive bacterium. Using aequorin, it is shown that B. subtilis cells tightly regulate intracellular Ca2+ levels. This homeostasis can be changed by an external stimulus such as hydrogen peroxide, pointing to a relationship between oxidative stress and Ca2+ signalling. Also, B. subtilis growth appears to be intimately linked to the presence of Ca2+, as normal growth can be immediately restored by adding Ca2+ to an almost non-growing culture in EGTA containing Luria broth medium. Addition of Fe2+ or Mn2+ also restores growth, but with 5-6 h delay, whereas Mg2+ did not have any effect. In addition, the expression of alkyl hydroperoxide reductase C (AhpC), which is strongly enhanced in bacteria grown in the presence of EGTA, also appears to be regulated by Ca2+. Finally, using 45Ca2+ overlay on membrane electrotransferred two-dimensional gels of B. subtilis, four putative Ca2+ binding proteins were found, including AhpC. Our results provide strong evidence for a regulatory role for Ca2+ in bacterial cells.     

Oleic acid blocks EGF-induced [Ca2+]i release without altering cellular metabolism in fibroblast EGFR T17

EGFR-T17 cells were pretreated with oleic acid and 5-10 minutes later stimulated with EGF, to study if early ionic signals are instrumental in inducing metabolic cellular response. Oleic acid blocks EGF-induced [Ca2+]i rise and Ca2+ influx without altering 2-deoxyglucose and 2-aminobutiryc acid uptake nor acute, nor chronically. Oleic acid it is shown, in the first minutes favors the entrance of both molecules to modify the physico-chemical membrane state. On the other hand, oleic acid is unable to block protein synthesis. The results suggest that EGF-induced Ins(1,4,5)P3/Ca2+ pathway does not seem to be decisive in the control of cellular metabolic activity.     

Metabolism of 2-amino-alpha-carboline. A food-borne heterocyclic amine mutagen and carcinogen by human and rodent liver microsomes and by human cytochrome P4501A2

In the present study, the responsive properties of afferent units in caudal nerve of streptozotocin (STZ) induced diabetic rats were investigated. It was found that some of the C and A delta units spontaneously discharged and their mechanical threshold was decreased significantly in diabetic rats. The response of the C units of diabetic and control rats to a 1 min sustained mechanical stimulus of threshold strength was similar, whereas, discharge frequencies during sustained suprathreshold mechanical stimulus were significantly greater in the C units of diabetic rats. After removal of threshold or suprathreshold mechanical stimulus, after discharges were also greater in C units of diabetic rats. Conduction velocity of C units, A delta units and A beta mechanical receptive units were also decreased in diabetic rats. However, there was no significant difference in the subunits of all kinds of receptive units between diabetic and control rats. The present data suggested that the C and A delta units with lowered mechanical threshold contribute to the decrease of the behavioral nociceptive threshold of diabetic rats and abnormal discharge of the C and A delta units may be a peripheral factor in hypersensitivity to painful stimuli and paresthesia of diabetic rats.     

Human neutrophils employ the myeloperoxidase-hydrogen peroxide-chloride system to oxidize alpha-amino acids to a family of reactive aldehydes. Mechanistic studies identifying labile intermediates along the reaction pathway

We have recently demonstrated that neutrophils oxidize nearly all of the amino acids commonly found in plasma to a corresponding family of aldehydes in high yield. The reaction is mediated by hypochlorous acid (HOCl), the major oxidant generated by the myeloperoxidase-H2O2-Cl- system of phagocytes. We now present evidence for the underlying mechanism of this reaction, including the structural requirements and reaction intermediates formed. Utilizing mass spectrometry and isotopically labeled amino acids, we rule out hydrogen atom abstraction from the alpha-carbon as the initial event in aldehyde formation during amino acid oxidation, a pathway known to occur with ionizing radiation. Aldehyde generation from amino acids required the presence of an alpha-amino moiety; beta- and epsilon-amino acids did not form aldehydes upon oxidation by either the myeloperoxidase system or HOCl, generating stable monochloramines instead. UV difference spectroscopy, high pressure liquid chromatography, and multinuclear (1H,15N) NMR spectroscopy established that the conversion of alpha-amino acids into aldehydes begins with generation of an unstable alpha-monochloramine, which subsequently decomposes to yield an aldehyde. Precursor product relationships between alpha-amino acid and alpha-monochloramine, and alpha-monochloramine and aldehyde were confirmed by high pressure liquid chromatography purification of the reaction intermediate and subsequent 1H and 15N NMR spectroscopy. Collectively, these results detail the chemical mechanism and reaction intermediates generated during conversion of amino acids into aldehydes by myeloperoxidase-generated HOCl.