A physiologic role of Bcl-xL induced in activated macrophages

Activated macrophages produce nitric oxide (NO) that is an important effector molecule for their antimicrobial and antitumor activities. Since this NO is also toxic for themselves, they have self-defense mechanisms. To elucidate the mechanisms in a physiologic condition, expression of bcl-2 family genes were examined in peritoneal macrophages and RAW264 macrophage cell line activated with IFN-gamma and LPS. Bcl-xL, but not bcl-2 and bax mRNA, was highly inducible within 3 h after stimulation. The induction required new protein synthesis, but was independent of effects of synthesized NO. Since activated RAW264 were more resistant to NO-induced apoptosis mediated by the exposure to S-nitroso-N-acetyl-penicillamine (SNAP) than nonactivated RAW264, the inducible Bcl-xL may play a role in the protection from NO toxicity. To confirm the protective function, RAW264 were stably transfected with bcl-xL. Those transfectants activated with IFN-gamma and LPS appeared highly resistant to NO-induced cell death detected within 24 h after stimulation, although their NO production was similar to those of parental RAW264 and neomycin control-transfected cells. Furthermore, bcl-xL transfectants displayed substantial protection from SNAP-induced apoptosis. These results establish a link between self-defense to the synthesized NO and the induction of Bcl-xL in activated macrophages.     

Relationship between morphological diversity and AgNORs or cathepsin B expression in colorectal cancers

The biological characteristics associated with the morphological diversity of colorectal cancers were investigated to elucidate the causes of this diversity. We examined the proliferative and infiltrating activity of tumor cells, indicated by the mean number of Ag nucleolar organizer region associated proteins (NORs) per nucleus (MNA) and the immunohistochemical response to cathepsin B(CB), in various morphological types of early and advanced colorectal cancers. We examined 73 colorectal cancers obtained by endoscopic and surgical resection. MNA values for sessile and flat-elevated cancers were greater than the values for pedunculate, subpedunculate, and flat-or-depressed early cancers (sessile, P < 0.05). In advanced cancers invading the muscularis propria, protruding cancers showed significantly higher MNA values than small ulcerative cancers (P < 0.01). CB expression increased significantly with the progression of colorectal cancers (P < 0.01), but was not related to morphological diversity in early and advanced cancers. In both sessile and flat cancers, CB expression was higher in moderately differentiated than in well differentiated adenocarcinomas. These results indicate that, in colorectal cancers, protruding early cancers without stalks and protruding advanced cancers have higher proliferative activity than pedunculate or flat early cancers and small ulcerative advanced cancers, respectively, and that CB expression is not associated with morphological diversity, but with depth of invasion and histological differentiation.     

Identification of interaction site of pseudoazurin with its redox partner, copper-containing nitrite reductase from Alcaligenes faecalis S-6

Pseudoazurin, a low molecular weight protein containing a singletype I copper, functions as an electron donor to a copper-containingnitrite reductase (NIR) in a denitrifying bacterium Alcaligenesfaecalis S-6. To elucidate the proteinprotein interaction betweenthese two copper-containing proteins, each of nine out of 13lysine residues on the surface of pseudoazurin were independentlyreplaced by alanine or aspartate, and the effects of the mutationson the interaction with NIR, as well as the physicochemicalproperties of pseudoazurin, were analyzed. All of the mutatedpseudoazurins showed optical spectra and oxidation-reductionpotentials almost identical to those of wildtype pseudoazurin,suggesting that none of the replacements of these lysine residuesaffected the environment around the type I copper site. Kineticanalysis of electron transfer between mutated pseudoazurinsand NIR reveals that the lysine mutations have very little effecton the rate of electron transfer to NIR, but substitution atresidues 10, 38, 57 and 77, all close to the copper site, substantiallydecreases the affinity of pseudoazurin for NIR. This suggeststhat pseudoazurin interacts with NIR through the region closeto the type I copper site. The refined X-ray structures of Lys38Aspand Lys10Asp/Lys38Asp show that the molecular structure hasindeed changed little. A new space group is observed for theLys109Ala mutant crystal. Crystal packing interactions changefor the Lys10Asp/Lys38Asp mutant but remain the same for Lys38Aspand Lys59Ala mutants.     

Optical coupling between coated fibers in a compact fiber ribbon

Optical coupling between coated optical fibers in a fiber ribbon for use in compact and high-density optical cable is described. By means of a measurement system having a sensitivity of -70 dB. optical coupling of -40 dB due to a small radius fiber bend is measured for an actual fiber ribbon coated with UV-curable resin. The optical coupling mechanism is discussed using analysis models of a coated optical fiber bend. Theoretical analyses and experimental results confirm that optical coupling occurs only when the refractive indices of coating materials satisfy the condition of radiating light traveling from a fiber core to a ribbon coat.     

The partial oxidation of ethane to acetaldehyde

The mixed oxide (B---P---O) prepared from H₃BO₃ and P₂O₅ was modified to a selective catalyst (B---P---O(S)) to the formation of CH₃CHO after prolonged treatment in a gas mixture of reactants. The contribution of gas-phase chain reactionsto the catalytic oxidations of C₂H₆ on the B---P---O(S) could be neglected. The catalytic active species on the B---P---O(S) was suggested to be a highly dispersed boron oxide supported on BPO₄ crystals. The mixed oxide prepared from BPO₄, H₃BO₃(7atom%), and P₂O₅(3atom%) showed the highest yield of CH₃CHO.     

Differential roles of Glu318 and Thr319 in cytochrome P450 1A2 catalysis supported by NADPH-cytochrome P450 reductase and tert-butyl hydroperoxide

The kinetic values for 7-ethoxycoumarin (7-EC) hydroxylation have been obtained in both the NADPH-cytochrome P450 reductase- and tert-butyl hydroperoxide (TBHP)-supported systems for several Glu318 and Thr319 mutants of cytochrome P450 1A2. The results with the reductase-supported system suggest that Glu318 is important for both substrate binding and catalysis, whereas Thr319 is critical for neither, although the size of the residue at position 319 influences catalytic activity. In contrast, neither Glu318 nor Thr319 appears to be important for catalytic turnover in the TBHP-supported system despite the fact that the size of the amino acid at position 319 affects the binding of TBHP and 7-EC in opposite manners. The roles of these two distal amino acids in the cytochrome P450 1A2-catalyzed oxidation of 7-EC therefore differ for the reactions supported by cytochrome P450 reductase and TBHP.     

Volatile anaesthetics attenuate hypocapnia-induced constriction in isolated dog cerebral arteries

The aim was to determine serum levels of prolactin (PRL) and dehydroepiandrosterone sulphate (DHEAS), and to demonstrate a link between PRL or DHEAS and soluble immune mediators in patients with systemic sclerosis (SSc) with different degrees of disease-induced organ involvement. Thirty-one patients with SSc were studied to evaluate 18 possible disease manifestations. In the serum, PRL, DHEAS and soluble immune mediators were determined by ELISA. Compared to SSc with <9 disease manifestations, patients with > or =9 disease manifestations had higher PRL (P = 0.044), higher soluble interleukin 2 receptor (sIL-2R, P = 0.004) and vascular cell adhesion molecule (sVCAM, P = 0.044), and lower DHEAS (P = 0.029). PRL (R(Rank) = 0.490, P = 0.003) and DHEAS (R(Rank) = -0.399, P = 0.013) were significantly correlated with the number of disease manifestations. The inverse correlation between PRL and DHEAS showed a trend (P = 0.059). PRL correlated with sIL-2R (R(Rank) = 0.553, P = 0.001) and sVCAM (R(Rank) = 0.520, P = 0.002). The number of disease manifestations and sIL-2R correlated significantly (R(Rank) = 0.463, P = 0.006). Psychometric variables to examine the presence of depression were not measured, but from the general aspect, the patients were not suffering from major depression which may have influenced our results. In conclusion, this study demonstrates the close association between DHEAS and, particularly, PRL and SSc severity and T-lymphocyte mechanisms.