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排序方式: 共有398条查询结果,搜索用时 46 毫秒
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Sara T. Elazab Nahla S. Elshater Yousreya H. Hashem Seung-Chun Park Walter H. Hsu 《Journal of veterinary pharmacology and therapeutics》2020,43(1):57-66
The pharmacokinetics of tylosin were investigated in 3 groups of ducks (n = 6). They received a single dose of tylosin (50 mg/kg) by intravenous (IV), intramuscular (IM), and oral administrations, respectively. Plasma samples were collected at various time points to 24 hr post-administration to evaluate tylosin concentration over time. Additionally, tylosin residues in tissues and its withdrawal time were assessed using 30 ducks which received tylosin orally (50 mg/kg) once daily for 5 consecutive days. After IV administration, the volume of distribution, elimination half-life, area under the plasma concentration–time curve, and the total body clearance were 7.07 ± 1.98 L/kg, 2.04 hr, 19.47 µg hr/ml, and 2.82 L hr−1 kg−1, respectively. After IM and oral administrations, the maximum plasma concentrations were 3.70 and 2.75 µg/ml achieved at 1 and 2 hr, and the bioavailability was 93.95% and 75.77%, respectively. The calculated withdrawal periods of tylosin were 13, 8, and 5 days for kidney, liver, and muscle, respectively. For the pharmacodynamic profile, the minimum inhibitory concentration for tylosin against M. anatis strain 1,340 was 1 µg/ml. The calculated optimal oral dose of tylosin against M. anatis in ducks based on the ex vivo pharmacokinetic/pharmacodynamic modeling was 61 mg kg−1 day−1. 相似文献
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Shang-Tse Ho Ying-Ning Ho Chih Lin Wei-Chen Hsu Han-Jung Lee Chia-Chi Peng Han-Tan Cheng Yu-Liang Yang 《Marine drugs》2021,19(4)
Empedopeptins—eight amino acid cyclic lipopeptides—are calcium-dependent antibiotics that act against Gram-positive bacteria such as Staphylococcus aureus by inhibiting cell wall biosynthesis. However, to date, the biosynthetic mechanism of the empedopeptins has not been well identified. Through comparative genomics and metabolomics analysis, we identified empedopeptin and its new analogs from a marine bacterium, Massilia sp. YMA4. We then unveiled the empedopeptin biosynthetic gene cluster. The core nonribosomal peptide gene null-mutant strains (ΔempC, ΔempD, and ΔempE) could not produce empedopeptin, while dioxygenase gene null-mutant strains (ΔempA and ΔempB) produced several unique empedopeptin analogs. However, the antibiotic activity of ΔempA and ΔempB was significantly reduced compared with the wild-type, demonstrating that the hydroxylated amino acid residues of empedopeptin and its analogs are important to their antibiotic activity. Furthermore, we found seven bacterial strains that could produce empedopeptin-like cyclic lipopeptides using a genome mining approach. In summary, this study demonstrated that an integrated omics strategy can facilitate the discovery of potential bioactive metabolites from microbial sources without further isolation and purification. 相似文献
86.
The effects of calcium (Ca2+), cadmium (Cd2+), and copper (Cu2+) cations on NADH‐linked electron transfer in com root plasma membrane vesicles were investigated. The reduction of both cytochrome c and ferricyanide were slightly stimulated by Ca2+ but not significantly affected by Cd2+. However, Cd2+ induced a redox‐linked increase in light scattering suggesting an increase in the size/volume of the vesicles. The presence of micromolar levels of Cu2+ decreased the reduction rates of both cytochrome c and ferricyanide. However, in contrast to ferricyanide reduction, Cu inhibition to the cytochrome c reduction was more effective, and was less sensitive to ionic strength. Copper inhibition changed the Michaelis‐Menten dependence of the ferricyanide reduction but not that of cytochrome c. These results suggest that the reduction of cytochrome c. and ferricyanide must occur at different membrane sites. 相似文献
87.
Eight new cembranoids, crassarines A-H (1-8) were isolated from the Formosan soft coral Sinularia crassa. Compounds 1-3 represent the rare cembranoids with a 1,12-oxa-bridged tetrahydrofuran ring, while 4 and 5 are the firstly discovered 1,11-oxa-bridged tetrahydropyranocembranoids. The absolute configuration of 6 was determined using the Mosher's method. Compounds 6 and 8 were found to significantly inhibit the expression of both pro-inflammatory iNOS and COX-2 proteins at 10 μM, respectively, while compounds 4-8 were found to be non-cytotoxic toward the selected human liver cancer cells. 相似文献
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Chia-Chang Lin Chao-Chiung Huang You-Liang Chen Ching-Wen Lou Chin-Mei Lin Chan-Hung Hsu Jia-Horng Lin 《Fibers and Polymers》2008,9(6):761-767
The energy of impact must decay and be transmitted after a bullet is shot through a ballistic-resistant cloth with a laminate
structure. A rigid net structure transmits the impact stress to reduce the breakage of the material in the direction perpendicular
to the fabric after the impacting of a projectile. This work combines the rigid net structure of stainless steel mesh with
two layers a needle-punched polyamide nonwoven fabric to create a sandwich-like laminate structure. A compound fabric that
is composed of a stainless steel mesh and polyamide nonwoven fabrics is placed in multi-layer Kevlar fabrics, and the buffer
effect is measured by performing a dropping weight impact test and a bullet-shooting test. The specifications of the stainless
steel mesh and the order of placement of the compound fabrics are varied to show the effect of these parameters on the energy
of fracture propagation and the buffer effect of the multi-layered Kevlar compound fabric that includes a layer of compound
fabric that is made of stainless steel mesh and polyamide nonwoven fabrics. In this study, the compound fabric replaces several
layers of Kevlar unidirectional fabric, to be used to reduce the cost of bulletproof vests without reducing ballistic resistance. 相似文献
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