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911.
Extracts ofPhellinus gilvus andPhellinus baumii inhibit pulmonary inflammation induced by lipopolysaccharide in rats 总被引:7,自引:0,他引:7
Jang BS Kim JC Bae JS Rhee MH Jang KH Song JC Kwon OD Park SC 《Biotechnology letters》2004,26(1):31-33
Compared to saline-challenged rats, rats exposed to 50 microg intratracheal lipopolysaccharide showed an increase of total white cells (from 0.3 x 10(6) to 2.4 x 10(6)), neutrophils (from 0.09 x 10(6) to 1.8 x 10(6)), the levels of tumor necrosis factor (TNF)-alpha (from 200 pg ml(-1) to 1200 pg ml(-1)), and interleukin (IL)-1beta (from 220 pg ml(-1) to 650 pg ml(-1)) in the bronchial lavage fluid. However, after pretreatment with extracts of Phellinus gilvus and Phellinus baumii, the total white cells, neutrophils, and the level of IL-1beta in lipopolysaccharide-challenged rats were similar to those in saline-challenged rats, except for TNF-alpha. The results indicate that extracts of P. gilvus and P. baumii may be useful in preventing acute pulmonary inflammation in human diseases. 相似文献
912.
Park YC Kim JB Heo Y Park DC Lee IS Chung HW Han JH Chung WG Vendeland SC Whanger PD 《Biological trace element research》2004,98(2):143-157
Intestinal metabolism of the subtoxic level of selenite in rats was investigated using a double-perfusion system, which is
an in situ, in vitro preparation in which the intestinal lumen and its vasculature are perfused simultaneously. The toxicity of sodium
selenite was determined by inhibition of 3-O-methyl glucose (3MG) absorption and by histological examination. Levels of 1.2 mM selenite were required to significantly (p<0.05) reduce 3MG intestinal absorption (58±11%, mean±SD). Cation-exchange chromatography was used to determine the chemical
forms of Se from selenite after using luminal concentrations of 1–200 μM in vascular perfusates. The chemical forms were selenite, selenodiglutathione (GS-Se-SG), mixed selenoglutathione plus cysteine
(GS-Se-CYS), selenodicysteine (CYS-Se-CYS), protein-bound Se, and unidentified selenocompounds. Selenite was the predominant
selenocompound found in vascular perfusate, but protein-bound Se was the predominant metabolite from selenite present in the
vascular effuents. There was a corresponding increase of all metabolites with increased levels of selenite with time of absorption,
but not with increased concentration of luminal selenite. 相似文献
913.
The use of animal cells such as Chinese hamster ovary (CHO) cells for recombinant gene expression provides many advantageous features such as proper folding and post-translational modification of the recombinant protein. However, recombinant genes introduced into animal cells are often expressed at low levels mainly due to position effects from the neighboring chromatin context. The tedious and time-consuming selection and amplification procedure has been the major hurdle for using animal cell line such as CHO cells. To improve mammalian cell expression systems, we screened a variety of matrix/scaffold attachment region (MAR/SAR) elements for their ability to insulate transgene expression from the position effects in CHO cells. We found that the human beta-globin MAR element is particularly effective as the frequency of beta-Gal positive colonies was increased by up to 80%. The expression levels of these colonies were also enhanced about seven-fold. These improvements appear to be related to the increased copy numbers and a higher efficiency of expression of the integrated genes. When this element was used to express soluble TGF-beta type II receptor (sTbetaRII) through the gene amplification system, the frequency of colonies expressing detectable amounts of sTbetaRII was much higher than that of the control vector. We could also generate high sTbetaRII producers with uniform growth properties by a simple two-step amplification process involving two concentrations of methotrexate. This eliminates the need to isolate individual colonies followed by multi-step treatments of methotrexate and thereby greatly simplifies this mammalian expression system. 相似文献
914.
The potential role of green tea polyphenol (GtPP) in preserving the human saphenous vein was investigated under physiological conditions. The vein segments were incubated for 1, 3, 5, 7 and 14 days, either after 4h of treatment with 1.0mg/ml GtPP or in the presence of GtPP at the same concentration. After incubation, the endothelial cell viability, endothelial nitric oxide synthase (eNOS) expression and the vein histology were evaluated. When the veins were not treated with GtPP, the viability of the endothelial cells was significantly reduced with the progress in the culture time, and none of the cells expressed eNOS after 5 days. Furthermore, severe histological changes and structural damage were observed in the non-treated veins. In contrast, incubating the veins after 4h of GtPP treatment significantly prevented these phenomena. The cellular viability of the GtPP-treated vein was approximately 64% after 7 days, and eNOS expression was maintained up to 40%, compared to that of the fresh vein. The histological observations showed that the vasculature was quite similar to that of the fresh vein. When incubated with GtPP, the vein could also be preserved for 1 week under physiological conditions retaining both its cellular viability (61%) and eNOS expression level (45%) and maintaining its venous structure without any morphological changes. These results demonstrate that GtPP treatment may be a useful method for preserving the HSV. 相似文献
915.
Safety and protective effect of a disinfectant (STEL water) for white spot syndrome viral infection in shrimp 总被引:1,自引:0,他引:1
Park JH Seok SH Cho SA Baek MW Lee HY Kim DJ Kim HY Chang SO Park JH 《Diseases of aquatic organisms》2004,60(3):253-257
The efficacy of STEL water for protection against white spot syndrome virus (WSSV) infection was evaluated using shrimp. The LC50 of residual chlorine (Cl-) in STEL water for brood-stock and 2-mo-old shrimp were 2.3 and 3.2 ppm, respectively. All 2-month-old shrimp raised in seawater containing more than 40 microl 2l(-1) of a WSSV-infected tissue homogenate died within 3 d post-exposure (dpe). Thus, a 10-fold dose of 400 microl 2 l(-1) was used in the disinfection tests. Low concentrations of STEL water effectively prevented mortality of shrimp at this challenge dose. All 2-month-old shrimp exposed to seawater with 400 microl of viral homogenate disinfected with STEL water at Cl- concentrations over 0.125 ppm for 1 and 10 min, lived until 5 dpe. With 5-mo-old shrimp, all positive control shrimps died within 3 dpe, whereas most shrimp reared in seawater disinfected with STEL water for 1 h before addition of homogenate lived until 5 dpe. Results suggested that continuous disinfection of seawater with STEL water may be effective for preventing WSSV infection in shrimp. 相似文献
916.
In order to determine if the infectious pancreatic necrosis virus isolate IPNV-Jasper (Ja-ATCC) is homogeneous or heterogeneous with respect to inhibition by normal rainbow trout serum (RTS), 50 clones were tested for sensitivity to RTS. The initial isolate was very sensitive to RTS, losing from 10(4) to 10(8) 50 % tissue culture infection dose (TCID50) ml(-1) with a 1:100 dilution of RTS. The sensitivity of the clones ranged from highly sensitive to completely resistant (0 to 10(8) TCID50 ml(-1) reduction). Eight percent of clones (4/50) were very sensitive to RTS (Ja-S) and 84% of clones (42/50) showed a mid-range of sensitivity to RTS. The final 8 % of clones (4/50) were resistant to RTS (Ja-R). Enzyme immunodot assay revealed that Ja-S clones showed a monoclonal reaction identical to the parents, Ja-ATCC; however, Ja-R clones differed by several epitopes from the parental strain. Analysis of Ja-S and Ja-R revealed that there were significant differences in their nucleic acid sequences for the capsid protein VP2. These 2 strains shared 80.7 and 86.5% identity in nucleic acid and in amino acid sequences, respectively. Ja-S had 99.7 and 91.0 % identity in nucleic acid sequences, and 99.5 and 95.9 % in amino acid sequences with Ja-ATCC and Jasper-Dobos (Ja-D), respectively, while Ja-R showed 80.6 and 79.8 % identity in nucleic acid sequences and 86.5 and 87.0 % in amino acid sequences with Ja-ATCC and Ja-D, respectively. In conclusion, the Ja-ATCC population was heterogeneous in terms of RTS sensitivity, serotype and cDNA sequences from the VP2 coding region. 相似文献
917.
Large-conductance voltage and Ca2+-activated potassium channels (BKCa) play a critical role in modulating contractile tone of smooth muscle, and neuronal processes. In most mammalian tissues, activation of β-adrenergic receptors and protein kinase A (PKAc) increases BKCa channel activity, contributing to sympathetic nervous system/hormonal regulation of membrane excitability. Here we report the requirement of an association of the β2-adrenergic receptor (β2AR) with the pore forming α subunit of BKCa and an A-kinase-anchoring protein (AKAP79/150) for β2 agonist regulation. β2AR can simultaneously interact with both BKCa and L-type Ca2+ channels (Cav1.2) in vivo, which enables the assembly of a unique, highly localized signal transduction complex to mediate Ca2+- and phosphorylation-dependent modulation of BKCa current. Our findings reveal a novel function for G protein-coupled receptors as a scaffold to couple two families of ion channels into a physical and functional signaling complex to modulate β-adrenergic regulation of membrane excitability. 相似文献
918.
Bioconversion of waste office paper to L(+)-lactic acid by the filamentous fungus Rhizopus oryzae 总被引:4,自引:0,他引:4
L(+)-lactic acid production was investigated using an enzymatic hydrolysate of waste office automation (OA) paper in a culture of the filamentous fungus Rhizopus oryzae. In 4 d culture, 82.8 g/l glucose, 7 g/l xylose, and 3.4 g/l cellobiose contained in the hydrolysate were consumed to produce 49.1 g/l of lactic acid. The lactic acid yield and production rate were only 0.59 g/g and 16.3 g/l/d, respectively, only 75% and 61% of the results from the glucose medium. The low production rate from waste OA hydrolysate was elucidated by trials using xylose as the sole carbon source; in those trials, the lactic acid production rate was 7.3 g/l/d, only 28% that of glucose or cellobiose. The low lactic acid yield from waste OA hydrolysate was clarified by trials using artificial hydrolysates comprised of 7:2:1 or 7:1:2 ratios of glucose:cellobiose:xylose. For both, the lactic acid production rate of 17.4 g/l/d matched that of waste OA paper, while the lactic acid yield was similar to that of the glucose medium. This indicates that the production rate may be inhibited by xylose derived from hemicellulose, and the yield may be inhibited by unknown compounds derived from paper pulp. 相似文献
919.
Lee SK Park EJ Lee E Min HY Kim EY Lee T Kim S 《Bioorganic & medicinal chemistry letters》2004,14(9):2105-2108
The inhibitory effects of a series of styrylheterocycles on the production of cyclooxygenase-2-mediated prostaglandin E(2) (PGE(2)) were evaluated in lipopolysaccharide-stimulated RAW264.7 murine macrophages. A new series of potential inhibitors, including 3-[2-(4-methoxy-phenyl)-vinyl]-thiophene, have been identified, thus providing novel chemical leads for the further development of potential inhibitors in this capacity. The suppression of COX-2 mRNA expression by the active styrylheterocycles, in part, was involved in the inhibitory activity against the overproduction of PGE(2). 相似文献
920.
Stearns BA Anker N Arruda JM Campbell BT Chen C Cramer M Hu T Jiang X Park K Ren KK Sablad M Santini A Schaffhauser H Urban MO Munoz B 《Bioorganic & medicinal chemistry letters》2004,14(5):1295-1298
A novel class of 6-aryl-6H-pyrrolo[3,4-d]pyridazine ligands for the alpha2delta subunit of voltage-gated calcium channels has been described. Substitutions in the aryl ring of the molecule were generally not tolerated, and resulted in diminished binding to the alpha2delta subunit. Modifications to the pyridazine ring revealed numerous permissive substitutions, and detailed SAR studies were carried out in this portion of the molecule. Replacement of the pyridazine ring methyl group with an aminomethyl functionality provided greatly improved potency over the initial lead. The initial lead compound displayed good rat pharmacokinetic properties, and was shown to be efficacious in the Chung model for neuropathic pain in rats. 相似文献