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181.
182.
H Mansour M Brun-Pascaud M A Gougerot-Pocidalo J J Pocidalo 《Comptes rendus de l'Académie des sciences. Série III, Sciences de la vie》1986,302(7):247-249
Inducers of cytochrome P450-linked mono-oxygenases increase the normobaric oxygen tolerance of the adult rat. Pulmonary inducers, as 3-methylcholanthrene and beta-naphthoflavone permit the rat survival and simultaneously a decrease of pulmonary edema. Phenobarbital, an hepatic inducer had lesser effects both on survival rate and on pulmonary and lympho?d oxygen toxicity. 相似文献
183.
Fructose-1-phosphate-6-sulfate was prepared by direct sulfurylation of fructose, and selective phosphorylation of the 6-sulfuryl isomer by phosphofructokinase. The ketose derivative was used as a substrate for aldolase and fructose-1,6-diphosphatase. Kinetic studies with aldolase showed that the alternative substrate binds one third as well as fructose-1,6-P2 yet 900 fold greater than fructose-1-P. The Vm was intermediate between the two ketose phosphates. From kinetic studies with skeletal muscle fructose-1,6-diphosphatase at pH 7.5 a Km of 8 μM and a Vm approximately 6% that for fructose-1,6-P2 was obtained. 相似文献
184.
Covalent modification of sheep heart phosphofructokinase with the affinity labeling reagent p-fluorosulfonyl[14C]benzoyl-5'-adenosine caused a loss of allosteric properties. This modification appears to occur at the binding site that is specific for the allosteric activators AMP, cAMP, and ADP (Mansour, T.E., and Colman, R.F. (1978) Biochem. Biophys. Res. Commun. 81, 1370-1376). In the current study, the site of modification has been demonstrated to be a lysine residue. A nonapeptide containing a covalently bound [14C]carboxybenzenesulfonyl group attached to alysine residue has been isolated following tryptic digestion. The amino acid sequence of the peptide is Asn-Phe-Ala-Thr-Lys-Met-Gly-Ala-Lys. The fifth residue in this sequence, lysine, contained the covalently bonded reagent. 相似文献
185.
186.
187.
Mohammed A. Mansour Wafaa M. Ibrahim Eman S. Shalaan Afrah F. Salama 《Journal of biochemical and molecular toxicology》2019,33(8)
Hexokinase‐2 is overexpressed in several carcinomas including breast cancer to sustain energy for rapidly dividing cells and associates with chemoresistance. However, the impact of chemo drugs (alone or in combination) on hexokinase activity and autophagic cell death is unclear. In this report, we used an in vivo murine adenocarcinoma model to validate the effects of As2O3 and cisplatin on hexokinase activity and autophagic cancer cell death. We found that the two drugs inhibit hexokinase activity and induce autophagic marker, beclin 1 expression. Interestingly, combining As2O3 with cisplatin synergistically enhanced these effects and alleviated oxidative stress often encountered in As2O3 treatment. Altogether, our data provide direct evidence that inhibition of hexokinase activity and induction of autophagic cell death are mediating the antineoplastic effects of As2O3 and cisplatin. Our findings raise the potential of combining As2O3 with cisplatin as an approach to augment cisplatin‐induced cell death and combat cisplatin chemoresistance in cancer. 相似文献
188.
The purpose of this study was to formulate topically effective controlled release ophthalmic acetazolamide liposomal formulations.
Reverse-phase evaporation and lipid film hydration methods were used for the preparation of reversephase evaporation (REVs)
and multilamellar (MLVs) acetazolamide liposomes consisting of egg phosphatidylcholine (PC) and cholesterol (CH) in the molar
ratios of (7∶2), (7∶4), (7∶6), and (7∶7) with or without stearylamine (SA) or dicetyl phosphate (DP) as positive and negative
charge inducers, respectively. The prepared liposomes were evaluated for their entrapment efficiency and in vitro release.
Multilamellar liposomes entrapped greater amounts of drug than REVs liposomes. Drug loading was increased by increasing CH
content as well as by inclusion of SA. Drug release rate showed an order of negatively charged > neutral > positively charged
liposomes, which is the reverse of the data of drug loading efficiency. Physical stability study indicated that approximately
89%, 77%, and 69% of acetazolamide was retained in positive, negative, and neutral MLVs liposomal formulations up to a period
of 3 months at 4°C. The intraocular pressure (IOP)-lowering activity of selected acetazolamide liposomal formulations was
determined and compared with that of plain liposomes and acetazolamide solution. Multilamellar acetazolamide liposomes revealed
more prolonged effect than REVs liposomes. The positively charged and neutral liposomes exhibited greater lowering in IOP
and a more prolonged effect than the negatively charged ones. The positive multilamellar liposomes composed of PC:CH:SA (7:4:1)
molar ratio showed the maximal response, which reached a value of −7.8±1.04 mmHg after 3 hours of topical administration.
Published: January 5, 2007 相似文献
189.
Cunningham D Danley DE Geoghegan KF Griffor MC Hawkins JL Subashi TA Varghese AH Ammirati MJ Culp JS Hoth LR Mansour MN McGrath KM Seddon AP Shenolikar S Stutzman-Engwall KJ Warren LC Xia D Qiu X 《Nature structural & molecular biology》2007,14(5):413-419
Proprotein convertase subtilisin kexin type 9 (PCSK9) lowers the abundance of surface low-density lipoprotein (LDL) receptor through an undefined mechanism. The structure of human PCSK9 shows the subtilisin-like catalytic site blocked by the prodomain in a noncovalent complex and inaccessible to exogenous ligands, and that the C-terminal domain has a novel fold. Biosensor studies show that PCSK9 binds the extracellular domain of LDL receptor with K(d) = 170 nM at the neutral pH of plasma, but with a K(d) as low as 1 nM at the acidic pH of endosomes. The D374Y gain-of-function mutant, associated with hypercholesterolemia and early-onset cardiovascular disease, binds the receptor 25 times more tightly than wild-type PCSK9 at neutral pH and remains exclusively in a high-affinity complex at the acidic pH. PCSK9 may diminish LDL receptors by a mechanism that requires direct binding but not necessarily receptor proteolysis. 相似文献
190.
ERVĪNS LUKŠEVIČS PER E. AHLBERG ĢIRTS STINKULIS JEĻENA VASIĻKOVA IVARS ZUPIŅŠ 《Lethaia: An International Journal of Palaeontology and Stratigraphy》2012,45(3):356-370
Luk?evi?s, E., Ahlberg, P.E., Stinkulis, ?., Vasi?kova, J. & Zupi??, I. 2011: Frasnian vertebrate taphonomy and sedimentology of macrofossil concentrations from the Langsēde Cliff, Latvia. Lethaia, Vol. 45, pp. 356–370. The siliciclastic sequence of the Upper Devonian of Kurzeme, Western Latvia, is renowned for abundant vertebrate fossils, including the stem tetrapods Obruchevichthys gracilis and Ventastega curonica. During the first detailed taphonomic study of the vertebrate assemblage from the Ogre Formation cropping out at the Langsēde Cliff, Imula River, abundant vertebrate remains have been examined and identified as belonging to one psammosteid, two acanthodian and three sarcopterygian genera; the placoderm Bothriolepis maxima dominates the assemblage. Besides fully disarticulated placoderm and psammosteid plates, separate sarcopterygian scales and teeth, and acanthodian spines, partly articulated specimens including complete distal segments of Bothriolepis pectoral fins, Bothriolepis head shields and sarcopterygian lower jaws have been found. The size distribution of the placoderm bones demonstrates that the individuals within the assemblage are of approximately uniform age. Distinct zones have been traced within the horizontal distribution of the bones. These linear zones are almost perpendicular to the dominant dip azimuth of the cross‐beds and ripple‐laminae and most probably correspond to the depressions between subaqueous dunes. Concavity ratio varies significantly within the excavation area. The degree of fragmentation of the bones and disarticulation of the skeletons suggest that the carcasses were reworked and slightly transported before burial. Sedimentological data suggest deposition in a shallow marine environment under the influence of rapid currents. The fossiliferous bed consists of a basal bone conglomerate covered by a cross‐stratified sandstone with mud drapes, which is in turn overlain by ripple laminated sandstone, indicating the bones were buried by the gradual infilling of a tidal channel. All the Middle–Upper Devonian vertebrate bone‐beds from Latvia are associated with sandy to clayey deposits and have been formed in a sea‐coastal zone during rapid sedimentation episodes, but differ in fossil abundance and degree of preservation. □Agnathans, Devonian, facies analysis, fish, fossil assemblage, palaeoenvironment. 相似文献