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191.
Marek Sanak Anna GieliczKrzysztof Nagraba Marek KaszubaJagoda Kumik Andrew Szczeklik 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2010,878(21):1796-1800
Background
Exhaled breath condensate collection is a non-invasive method of sampling the respiratory tract that can be repeated several times in a wide range of clinical settings. Quantitation of non-volatile compounds in the condensate requires highly sensitive analytical methods, e.g. mass spectrometry.Objective
To validate cross-platform measurements of eicosanoids using high performance liquid chromatography or gas chromatography coupled with mass spectrometry in exhaled breath condensate sampled from 58 healthy individuals.Methods
Twenty different eicosanoid compounds, representing major arachidonic acid lipoxygenation and cyclooxygenation pathways were measured using a stable isotope dilution method. We applied a free palmitic acid concentration as a surrogate marker for the condensate dilution factor.Results
Eicosanoids concentrations in the condensates were consistent with their content in other biological fluids. Prostaglandin E2 was the most abundant mediator, represented by its stable metabolite tetranor-PGEM. Prostaglandin D2 products were at low concentration, while hydroxyacids derived from lipoxygenation were abundant. 5-HETE was elevated in current tobacco smokers. Leukotriene B4 has the highest concentration of all 5-LO products. 15-LO analogues of cysteinyl leukotrienes–eoxins were detectable and metabolized to eoxin E4. Two main vascular prostanoids: prostacyclin and thromboxane B2 were present as metabolites. A marker for non-enzymatic lipid peroxidation, 8-iso-PGF2α isoprostane was increased in smokers.Conclusion
Presented targeted lipidomics analysis of exhaled breath condensate in healthy subjects justifies its application to investigation of inflammatory lung diseases. Measurements of non-volatile mediators of inflammation in the condensates might characterize disease-specific pathological mechanisms and responses to treatment. 相似文献192.
Martin Hucík Marek Bučko Peter Gemeiner Vladimír Štefuca Alica Vikartovská Marko D. Mihovilovič Florian Rudroff Naseem Iqbal Dušan ChorvátJr. Igor Lacík 《Biotechnology letters》2010,32(5):675-680
Recombinant Escherichia coli cells, over-expressing cyclopentanone monooxygenase activity, were immobilized in polyelectrolyte complex capsules, made
of sodium alginate, cellulose sulfate, poly(methylene-co-guanidine), CaCl2 and NaCl. More than 90% of the cell viability was preserved during the encapsulation process. Moreover, the initial enzyme
activity was fully maintained within encapsulated cells while it halved in free cells. Both encapsulated and free cells reached
the end point of the Baeyer–Villiger biooxidation of 8-oxabicyclo[3.2.1]oct-6-en-3-one to 4,9-dioxabicyclo[4.2.1]non-7-en-3-one
at the same time (48 h). Similarly, the enantiomeric excess above 94% was identical for encapsulated and free cells. 相似文献
193.
Hana Nůsková Marek Vrbacký Zdeněk Drahota Josef Houštěk 《Journal of bioenergetics and biomembranes》2010,42(5):395-403
The mechanism of cyanide’s inhibitory effect on the mitochondrial cytochrome c oxidase (COX) as well as the conditions for its recovery have not yet been fully explained. We investigated three parameters
of COX function, namely electron transport (oxygen consumption), proton transport (mitochondrial membrane potential Δψ
m) and the enzyme affinity to oxygen (p
50
value) with regard to the inhibition by KCN and its reversal by pyruvate. 250 μM KCN completely inhibited both the electron
and proton transport function of COX. The inhibition was reversible as demonstrated by washing of mitochondria. The addition
of 60 mM pyruvate induced the maximal recovery of both parameters to 60–80% of the original values. When using low KCN concentrations
of up to 5 μM, we observed a profound, 30-fold decrease of COX affinity for oxygen. Again, this decrease was completely reversed
by washing mitochondria while pyruvate induced only a partial, yet significant recovery of oxygen affinity. Our results demonstrate
that the inhibition of COX by cyanide is reversible and that the potential of pyruvate as a cyanide poisoning antidote is
limited. Importantly, we also showed that the COX affinity for oxygen is the most sensitive indicator of cyanide toxic effects. 相似文献
194.
Gregory Engel Todd M. O'Hara Tamara Cardona‐Marek John Heidrich Mukesh K. Chalise Randall Kyes Lisa Jones‐Engel 《American journal of physical anthropology》2010,142(3):453-460
Macaques are similar to humans both physiologically and behaviorally. In South and Southeast Asia they are also synanthropic, ecologically associated with humans. Synanthropy with humans raises the possibility that macaques come into contact with anthropogenic toxicants, such as lead and mercury, and might be appropriate sentinels for human exposures to certain toxic materials. We measured lead (Pb) and mercury (Hg) levels and characterized the stable isotopic compositions of δ15N and δ13C in hair from three groups of free‐ranging macaques at the Swoyambhu temple in Kathmandhu, Nepal, an urban population that has abundant contact with humans. Hair lead levels were significantly higher among young macaques and differed among the three groups of macaques that were sampled. Hair Hg levels were low. No statistical association was found between stable isotopic compositions (δ15N and δ13C) and Pb and Hg levels. Our data did not find evidence that lead levels were associated with diet. We conclude that, in this population of macaques, behavioral and/or physiologic factors may play a significant role in determining exposure to lead. Chemical analysis of hair is a promising, noninvasive technique for determining exposure to toxic elements in free‐ranging nonhuman primates. Am J Phys Anthropol, 2010. © 2009 Wiley‐Liss, Inc. 相似文献
195.
Piekarska K Zacharczuk K Bareja E Olak M Szych J Jagielski M Wardak S Gierczyński R 《Medycyna do?wiadczalna i mikrobiologia》2010,62(3):201-209
Resistance to gentamicin, amikacin and kanamycin was screened in 270 clinical isolates of Enterobacteriaceae originated from April 19 to May 19, 2010 in a regular hospital in Warsaw, Poland. Most of the isolated bacteria were considered pathogenic. Nineteen isolates (7%) were simultaneously resistant to two or three of the tested aminoglycosides. MICs of the three aminoglycosides ranged form 128 to 1024 mcg/ml for six isolates. These isolates were suspected to produce 16S rRNA methylase. Genes encoding for three methylases reported in Europe: ArmA, RmtB and RmtC were searched by PCR. The armA gene was detected in all of the six isolates. This group encompassed Enterobacter cloacae (n=4), Klebsiella pneumoniae (n=1) and Proteus mirabilis (n=1). Five isolates of this group carried the bla(CAX-M) gene for CTX-M type ESBL. The remaining isolate E. cloacae DM0340 was ESBL negative and lacked bla(CRX-M) that may suggest an altered genetic environment of the armA gene in this isolate. Our results showed that 2.2% of the tested isolates produced 16S rRNA methylase ArmA. This finding may argue for a high incidence of ArmA producing Enterobacteriaceae in Poland when compared to reports from other European countries. 相似文献
196.
Christian Tanislav Manfred Kaps Marek Jauss Erwin Stolz Wolfgang Pabst Max Nedelmann Mathias Grebe Frank Reichenberger Jens Allendoerfer 《BMC neurology》2010,10(1):123
Background
In patients with patent foramen ovale (PFO) there is evidence supporting the hypothesis of a change in right-to-left shunt (RLS) over time. Proven, this could have implications for the care of patients with PFO and a history of stroke. The following study addressed this hypothesis in a cohort of patients with stroke and PFO. 相似文献197.
198.
Jan Zouhar Jitka Vvodov Jaromír Marek Jií Damborský Xiao-Dong Su Betislav Brzobohatý 《Plant physiology》2001,127(3):973-985
The maize (Zea mays) beta-glucosidase Zm-p60.1 has been implicated in regulation of plant development by the targeted release of free cytokinins from cytokinin-O-glucosides, their inactive storage forms. The crystal structure of the wild-type enzyme was solved at 2.05-A resolution, allowing molecular docking analysis to be conducted. This indicated that the enzyme specificity toward substrates with aryl aglycones is determined by aglycone aromatic system stacking with W373, and interactions with edges of F193, F200, and F461 located opposite W373 in a slot-like aglycone-binding site. These aglycone-active site interactions recently were hypothesized to determine substrate specificity in inactive enzyme substrate complexes of ZM-Glu1, an allozyme of Zm-p60.1. Here, we test this hypothesis by kinetic analysis of F193I/Y/W mutants. The decreased K(m) of all mutants confirmed the involvement of F193 in determining enzyme affinity toward substrates with an aromatic aglycone. It was unexpected that a 30-fold decrease in k(cat) was found in F193I mutant compared with the wild type. Kinetic analysis and computer modeling demonstrated that the F193-aglycone-W373 interaction not only contributes to aglycone recognition as hypothesized previously but also codetermines catalytic rate by fixing the glucosidic bond in an orientation favorable for attack by the catalytic pair, E186 and E401. The catalytic pair, assigned initially by their location in the structure, was confirmed by kinetic analysis of E186D/Q and E401D/Q mutants. It was unexpected that the E401D as well as C205S and C211S mutations dramatically impaired the assembly of a catalysis-competent homodimer, suggesting novel links between the active site structure and dimer formation. 相似文献
199.
Marian Pavelka Manuel Acosta Michal V. Marek Werner Kutsch Dalibor Janous 《Plant and Soil》2007,292(1-2):171-179
The parameter Q10 is commonly used to express the relationship between soil CO2 efflux and soil temperature. One advantage of this parameter is its application in a model expression of respiration losses
of different ecosystems. Correct specification of Q10 in these models is indispensable. Soil surface CO2 efflux and soil temperature at different depths were measured in a 21-year-old Norway spruce stand and a mountain grassland
site located at the Experimental Ecological Study Site Bily Kriz, Beskydy Mts. (NE Czech Republic), using automated gasometric
systems. A time-delay and goodness-of-fit between soil CO2 efflux and soil temperature at different measuring depths were determined. Wide ranges of values for the time-delay of CO2 efflux in response to temperature, Q10 and the determination coefficient (R2) between CO2 efflux and temperature were obtained at the both sites. The values of Q10 and the CO2 time-delay increased with depth, while the R2 of the CO2-temperature relationship significantly decreased. Soil temperature records obtained close to the soil surface showed the
highest values of R2 and the lowest value of the time-delay at both sites. Measurement of soil temperature at very shallow soil layer, preferably
at the soil surface, is highly recommended to determine useable values of Q10. We present a new procedure to normalize Q10 values for soil temperatures measured at different depths that would facilitate comparison of different sites. 相似文献