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171.
Graeme R Zosky Tibor Z Janosi Agnes Adamicza Elizabeth M Bozanich Vincenzo Cannizzaro Alexander N Larcombe Debra J Turner Peter D Sly Zoltán Hantos 《Journal of applied physiology》2008,105(2):685-692
The double sigmoidal nature of the mouse pressure-volume (PV) curve is well recognized but largely ignored. This study systematically examined the effect of inflating the mouse lung to 40 cm H2O transrespiratory pressure (Prs) in vivo. Adult BALB/c mice were anesthetized, tracheostomized, and mechanically ventilated. Thoracic gas volume was calculated using plethysmography and electrical stimulation of the intercostal muscles. Lung mechanics were tracked during inflation-deflation maneuvers using a modification of the forced oscillation technique. Inflation beyond 20 cm H2O caused a shift in subsequent PV curves with an increase in slope of the inflation limb and an increase in lung volume at 20 cm H2O. There was an overall decrease in tissue elastance and a fundamental change in its volume dependence. This apparent "softening" of the lung could be recovered by partial degassing of the lung or applying a negative transrespiratory pressure such that lung volume decreased below functional residual capacity. Allowing the lung to spontaneously recover revealed that the lung required approximately 1 h of mechanical ventilation to return to the original state. We propose a number of possible mechanisms for these observations and suggest that they are most likely explained by the unfolding of alveolar septa and the subsequent redistribution of the fluid lining the alveoli at high transrespiratory pressure. 相似文献
172.
Biró E Németh AS Sisak C Feczkó T Gyenis J 《Journal of biochemical and biophysical methods》2008,70(6):1240-1246
Macro-, micro- and nanosized chitosan particles suitable as immobilization carriers were prepared by precipitation, emulsion cross-linking and ionic gelation methods, respectively. Effects of particle preparation parameters on particle size were investigated. Activities of β-galactosidase covalently attached to differently sized particles have been evaluated and compared. The highest activity was shown by the biocatalyst immobilized on nanoparticles obtained by means of the ionotropic gelation method with sodium sulphate as gelation agent. β-Galactosidase fixed on macro- and microspheres exhibited excellent storage stability in aqueous solution, with no more than 5% loss of activity after 3 weeks storage at 4 °C and pH 7.0. 相似文献
173.
174.
Eden Ephraim Agnes Odenyo Mogessie Ashenafi 《World journal of microbiology & biotechnology》2005,21(6-7):803-809
Summary Tannins limit the use of fodder trees as feed for ruminants. Removal of the effects of tannins would thus improve the nutritional
quality of these trees. This prompted the study to evaluate the effect of rumen or faecal mixed cultures from different animals
on tannin degradation. Tannin extracts, tannic acid and gallic acid were used to enrich media to assess if rumen or faecal
mixed cultures could degrade the phenolic compounds. Rumen fluid of Acacia-adapted sheep, sheep fed on wheat bran, bush duikers (Sylvicapra grimmia) and goats fed on Leucaena pallida and Sesbania goetzei were separately inoculated into Growth Study Medium (GSM) and incubated for 5-15 days. Faecal samples from dikdik (Madoqua guentheri), camel (Camelus dromedarius), zebra (Equus quagga), Grant’s gazelle (Gazella granti) and hartebeest (Alcelaphus buselaphus) were also separately inoculated into GSM media and incubated from 3-5 days. TLC results showed that mixed cultures from
rumen fluids of Acacia-adapted sheep, sheep on wheat bran, goats on Leucaena pallida and Sesbania goetzei partially hydrolysed tannic acid to pyrogallol. Complete degradation of the heterocyclic ring in tannic acid and gallic acid
was achieved by the mixed cultures from the faecal samples of dikdik and this was confirmed by HPLC. Mixed cultures from faecal
samples of camel hydrolysed gallic acid to phloroglucinol. This study has demonstrated that faecal microorganisms of Ethiopian
dikdik could completely degrade hydrolysable tannin. 相似文献
175.
A comparison of cDNA, oligonucleotide, and Affymetrix GeneChip gene expression microarray platforms.
Yong Woo Jason Affourtit Sandra Daigle Agnes Viale Kevin Johnson Jurgen Naggert Gary Churchill 《Journal of biomolecular techniques》2004,15(4):276-284
We have conducted a study to compare the variability in measured gene expression levels associated with three types of microarray platforms. Total RNA samples were obtained from liver tissue of four male mice, two each from inbred strains A/J and C57BL/6J. The same four samples were assayed on Affymetrix Mouse Genome Expression Set 430 GeneChips (MOE430A and MOE430B), spotted cDNA microarrays, and spotted oligonucleotide microarrays using eight arrays of each type. Variances associated with measurement error were observed to be comparable across all microarray platforms. The MOE430A GeneChips and cDNA arrays had higher precision across technical replicates than the MOE430B GeneChips and oligonucleotide arrays. The Affymetrix platform showed the greatest range in the magnitude of expression levels followed by the oligonucleotide arrays. We observed good concordance in both estimated expression level and statistical significance of common genes between the Affymetrix MOE430A GeneChip and the oligonucleotide arrays. Despite their apparently high precision, cDNA arrays showed poor concordance with other platforms. 相似文献
176.
177.
Gabor A. Balint Marta Galfi Anna Juhasz Ferenc A. Laszl Agnes Rimanczy 《Journal of Physiology》2001,95(1-6):173-175
Homozygous Brattleboro rats were investigated and compared to normal (physiological) Wistar strain rats regarding their gastric mucosal endogenous prostacyclin (PG-I(2)) level. It seems that the Brattleboro animals have a significantly lower level of this important protective material. Wistar rats having an artificial pituitary stalk lesion (which is the artificial equivalent of homozygous Brattleboro animals) showed no differences in endogenous mucosal prostacyclin level compared to normal Wistar rats. Therefore, we concluded that this hitherto unknown property of the homozygous Brattleboro rats is genetically determined. 相似文献
178.
179.
Cheuk Y. Lee Agnes S.K. Lee Shin C. Chiu 《Biochimica et Biophysica Acta (BBA)/General Subjects》1977,499(3):443-446
Phosphofructokinase activity in rat testis is elevated by treatment in vitro with human chorionic gonadotropin or N6, O2′-dibutyryladenosine 3′,5′-monophosphate. Puronycin or actinomycin D suppresses the effect of the gonadotropin but does not affect the enzyme increase induced by the cyclic nucleotide. The possible cause for the divergent action of the two stimulatory agents are discussed. 相似文献
180.
Agnes Savill 《BMJ (Clinical research ed.)》1917,1(2924):65-66