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31.
Pei-Li Yao Meng-Feng Tsai Yi-Chen Lin Chien-Hsun Wang Wei-Yu Liao Jeremy JW Chen Pan-Chyr Yang 《Respiratory research》2005,6(1):89
Background
Theophylline has been used widely as a bronchodilator for the treatment of bronchial asthma and has been suggested to modulate immune response. While the importance of macrophages in asthma has been reappraised and emphasized, their significance has not been well investigated. We conducted a genome-wide profiling of the gene expressions of macrophages in response to theophylline.Methods
Microarray technology was used to profile the gene expression patterns of macrophages modulated by theophylline. Northern blot and real-time quantitative RT-PCR were also used to validate the microarray data, while Western blot and ELISA were used to measure the levels of IL-13 and LTC4.Results
We identified dozens of genes in macrophages that were dose-dependently down- or up-regulated by theophylline. These included genes related to inflammation, cytokines, signaling transduction, cell adhesion and motility, cell cycle regulators, and metabolism. We observed that IL-13, a central mediator of airway inflammation, was dramatically suppressed by theophylline. Real-time quantitative RT-PCR and ELISA analyses also confirmed these results, without respect to PMA-treated THP-1 cells or isolated human alveolar macrophages. Theophylline, rolipram, etazolate, db-cAMP and forskolin suppressed both IL-13 mRNA expression (~25%, 2.73%, 8.12%, 5.28%, and 18.41%, respectively) and protein secretion (<10% production) in macrophages. These agents also effectively suppressed LTC4 expression.Conclusion
Our results suggest that the suppression of IL-13 by theophylline may be through cAMP mediation and may decrease LTC4 production. This study supports the role of theophylline as a signal regulator of inflammation, and that down regulation of IL-13 by theophylline may have beneficial effects in inflammatory airway diseases. 相似文献32.
J W Wimpenny 《Journal of general microbiology》1967,47(3):379-388
33.
Aldair JW Pinto Maria M Figueiredo Fabiana L Silva Trycia Martins Marilene SM Michalick Washington L Tafuri Wagner L Tafuri 《Acta veterinaria Scandinavica》2011,53(1):1-8
Background
A nationwide survey on the microbial etiology of cases of subclinical mastitis in dairy cows was carried out on dairy farms in Sweden. The aim was to investigate the microbial panorama and the occurrence of antimicrobial resistance. Moreover, differences between newly infected cows and chronically infected cows were investigated.Methods
In total, 583 quarter milk samples were collected from 583 dairy cows at 226 dairy farms from February 2008 to February 2009. The quarter milk samples were bacteriological investigated and scored using the California Mastitis Test. Staphylococci were tested for betalactamase production and presence of resistance was evaluated in all specific udder pathogens. Differences between newly infected cows and chronically infected cows were statistically investigated using logistic regression analysis.Results
The most common isolates of 590 bacteriological diagnoses were Staphylococcus (S) aureus (19%) and coagulase-negative staphylococci (CNS; 16%) followed by Streptococcus (Str) dysgalactiae (9%), Str. uberis (8%), Escherichia (E.) coli (2.9%), and Streptococcus spp. (1.9%). Samples with no growth or contamination constituted 22% and 18% of the diagnoses, respectively. The distribution of the most commonly isolated bacteria considering only bacteriological positive samples were: S. aureus - 31%, CNS - 27%, Str. dysgalactiae - 15%, Str. uberis - 14%, E. coli - 4.8%, and Streptococcus spp. - 3.1%. There was an increased risk of finding S. aureus, Str. uberis or Str. dysgalactiae in milk samples from chronically infected cows compared to findings in milk samples from newly infected cows. Four percent of the S. aureus isolates and 35% of the CNS isolates were resistant to penicillin G. Overall, resistance to other antimicrobials than penicillin G was uncommon.Conclusions
Staphylococcus aureus and CNS were the most frequently isolated pathogens and resistance to antimicrobials was rare. 相似文献34.
One approach to developing a mathematical model that predicts osteoactivity both in bio-scaffolds, as well as the in bone tissue in vivo, is based on a bio-cybernetic vision of basic multicellular unit (BMU) action. In the case of the model presented in this paper, some of the loops of regulation have been modified to reflect the range of allosteric control mechanisms: Michaelis-Menten, Hill, Adair, Koshland-Nemethy-Filmer (KNF), Monod-Wyman-Changeux (MWC). This approach has resulted in a four-dimensional system that shows steady cyclic behaviour using a range of constants with clear biological meaning. The initial findings suggesting that a steady state appears as a cycle in multidimensional phase space and this is discussed in this paper. The existence of this cycle in the osteoclasts-osteoblasts-osteocytes-bone subspace indicates that there is a conservative value along steady trajectories for this dynamic system. Biophysical interpretation of this conservative value has been proposed as a kind of substrate-energy regenerative potential of the bone remodelling system with a similarity to the classical physical value-energy. Such a recovery "potential" is directed against both mechanical and biomechanical damage to the bone. The current model has credibility when compared to the normal bone remodelling process. In the framework of widely recognised Michaelis-Menten mechanisms of allosteric regulation the cyclic attractor, described formerly for a pure cellular model, prevails for different forms of feedback control. This finding demonstrates the viability of the suggestion of the subsistence of conservative value (analogous to energy) that characterises the recovery potential of the bone remodelling cycle. The results indicate that the robust behaviour of the model is maintained from the simple cellular level to the molecular biochemical level of regulation. 相似文献
35.
36.
Premelting at the surface of ice crystals is caused by factors such as temperature, radius of curvature, and solute composition. When polycrystalline ice samples are warmed from well below the equilibrium melting point, surface melting may begin at temperatures as low as -15 degrees C. However, it has been reported (. Biophys. J. 65:1853-1865) that when polycrystalline ice was warmed in a differential scanning calorimetry (DSC) pan, melting began at about -50 degrees C, this extreme behavior being attributed to short-range forces. We show that there is no driving force for such premelting, and that for pure water samples in DSC pans curvature effects will cause premelting typically at just a few degrees below the equilibrium melting point. We also show that the rate of warming affects the slope of the DSC baseline and that this might be incorrectly interpreted as an endotherm. The work has consequences for DSC operators who use water as a standard in systems where subfreezing runs are important. 相似文献
37.
38.
Method for Investigation of Competition between Bacteria as a Function of Three Environmental Factors Varied Simultaneously 总被引:1,自引:1,他引:0 下载免费PDF全文
Competition between microorganisms as affected by temperature, pH, and the sodium chloride (NaCl) concentration was investigated by selective replication from gradient plates. Salmonella typhimurium was inhibited by Pseudomonas putida at 20 and 23°C but not 30 and 35°C. P. putida no longer grew at the extremes of pH and NaCl concentration, particularly at 30 and 35°C. 相似文献
39.
Positions of multiple insertions in SSU rDNA of lichen-forming fungi 总被引:11,自引:3,他引:8
Lichen-forming fungi, in symbiotic associations with algae, frequently have
nuclear small subunit ribosomal DNA (SSU rDNA) longer than the 1,800
nucleotides typical for eukaryotes. The lichen-forming ascomycetous fungus
Lecanora dispersa contains insertions at eight distinct positions of its
SSU rDNA; the lichen-forming fungi Calicium tricolor and Porpidia
crustulata each contain one insertion. Insertions are not limited to fungi
that form lichens; the lichen ally Mycocalicium albonigrum also contains
two insertions. Of the 11 insertion positions now reported for
lichen-forming fungi and this ally, 6 positions are known only from
lichen-forming fungi. Including the 4 newly reported in this study,
insertions are now known from at least 17 positions among all reported SSU
rDNA sequences. Insertions, most of which are Group I introns, are reported
in fungal and protistan lineages and occur at corresponding positions in
genomes as phylogenetically distant as the nuclei of fungi, green algae,
and red algae. Many of these positions are exposed in the mature rRNA
tertiary structure and may be subject to independent insertion of introns.
Insertion of introns, accompanied by their sporadic loss, accounts for the
scattered distribution of insertions observed within the SSU rDNA of these
diverse organisms.
相似文献
40.
The extent of polylactosamine glycosylation of MDCK LAMP-2 is determined by its Golgi residence time 总被引:2,自引:1,他引:1
The increased polylactosamine glycosylation of LAMP-2 in MDCK cells
cultured for 1 day relative to cells cultured for 3 days has been
correlated with its slower rate of Golgi transit (Nabi and Rodriguez-
Boulan, 1993, Mol. Biol. Cell., 4, 627-635). To determine if the
differential polylactosamine glycosylation of LAMP-2 is a consequence of
glycosyltransferase expression levels, the activities of beta1- 6GlcNAc-TV,
beta1-3GlcNAc-T(i), beta1-2GlcNAc-TI, beta1, 4Gal-T, alpha2- 6sialyl-T, and
alpha2-3sialyl-T were assayed and no significant differences in the
activities of these enzymes in 1 and 3 day cell extracts were detected.
During MDCK epithelial polarization, the Golgi apparatus undergoes
morphological changes and apiconuclear Golgi networks were more evident in
3 day cells. Treatment with nocodazole disrupted Golgi networks and
generated numerous Golgi clusters in both 1 day and 3 day cells. In the
presence of nocodazole the differential migration of LAMP-2 in 1 and 3 day
MDCK cells was maintained and could be eliminated by treatment with
endo-beta-galactosidase, indicating that gross Golgi morphology did not
influence the extent of LAMP-2 polylactosamine glycosylation. Nocodazole
treatment did, however, result in the faster migration of LAMP-2 which was
not due to modification of core N-glycans as the precursor form of the
glycoprotein migrated with an identical molecular size. Following
incubation at 20 degrees C, which prevents the exit of proteins from the
trans-Golgi network, the molecular size of LAMP-2 increased to a similar
extent in both 1 and 3 day MDCK cells. Extending the time of incubation at
20 degrees C did not influence the size of LAMP-2, demonstrating that its
glycosylation is modified not by its retention within the Golgi but rather
by its equivalent slower Golgi passage at the lower temperature in both 1
and 3 day cells. An identical effect was observed in nocodazole treated
cells, demonstrating that Golgi residence time determines the extent of
LAMP-2 polylactosamine glycosylation, even in isolated Golgi clusters.
相似文献