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Objective@#To investigate the determinants affecting the heart rate deceleration capacity (DC) in patients with dilated cardiomyopathy (DCM).@*Methods@#One hundred patients with DCM (DCM group) and 202 healthy subjects (control group) were respectively enrolled. Echocardiography and 24 hours electrocardiogram were performed in all subjects. DC value was compared between the two groups. Multiple regression analysis was made to evaluate the related determinants of DC ((age, sex, echocardiographic parameters including the left atrial diameter (LAD) and left ventricular ejection fraction (LVEF)).@*Results@#(1) DC value was significantly lower in DCM group than in control group( (4.40±2.03) ms vs. (7.30±1.81) ms, P<0.01), prevalence of DC value≤4.5 ms was significantly higher in DCM group than in control group (62% vs. 6%, P<0.01). (2) DC value in the DCM group decreased in proportion to increasing LAD dimension, DC value was (5.60±2.04) ms, (4.50±2.07) ms and (3.60±1.62) ms (P<0.05) in DCM patients with LAD≤40 mm, 40 mm<LAD≤50 mm and LAD>50 mm, respectively. (3) DC value in the DCM group was negatively related to the LAD (r=-0.366, P<0.01), positively related to the LVEF (r= 0.241, P<0.01), but not related with age and sex. Multiple factors regression analysis showed that increased LAD was related to the reduced DC values independtly.@*Conclusion@#DC value of the patients in the DCM group is decreased, which indicate the decrease of the vagus nerve tension, and increased LAD is related to the reduced DC value independtly in DCM patients.
ABSTRACT
Objective To study the antibacterial mechanisms of berberine and try to understand the reasons why bacteria cells difficultly resisted to it. Methods Detecting the minimal inhibitory concentration (MIC) of bacterial cultures incubated under sub-MIC concentration of berberine, Huanglian, and Neomycin for more than 200 generations, in order to analyze the bacteria resistance. Detecting the binding kinetics of berberine to DNA, RNA, and proteins. Observing the changes in bacterial cell surface structure with scanning electron microscopy. Detecting the Ca2+ and K.+ released from berberine-treated bacterial cells with atomic absorption spectrum. Detection the absorption of methyl-3H-thymine (3H-dT), 3H-uridine (3H-U), and 3H-tyrosine (3H-Tyr) into berberine-treated bacterial cells. Results MICs of bacterial cultures, growing more than 200 generations in MH medium with 1/2 MIC of berberine (BA200) or Huanglian (HA200), did not increase compared to the control, while remarkably increased in MH medium with 1/2 MIC of Neomycin (NA200). In addition, from the culture NA200 it was easy to isolate resistant mutant strains which could grow in MH medium with more than four times MIC Neomycin, but from the culture BA200 and HA200 it was difficult to isolate berberine or Huanglian mutant strains could grow in MH medium with more than four times MIC berberine or Huanglian. The binding kinetics of berberine to DNA, RNA, and proteins illustrated that berberine could easily and tightly bind to DNA and RNA, and hardly dis-bind from DNA- and RNA-berberine complexes. Berberine could easily bind to protein too, but also easily dis-bind from berberine-protein complex. The bacterial cells treated with berberine sharply decreased the absorption of 3H-dT, 3H-U, and 3H-Tyr, as the radioactive precursors of DNA, RNA, and protein biosynthesis. Berberine could damage bacterial cell surface structure, especially for Gram-negative bacteria. Ca2+ and K+ released from berberine-treated cells increased significantly compared to the control. Conclusion All of above results indicate that bacterial cells could not easily become resistant mutants to berberine. The mechanisms for the bactericidal effect of berberine include: inhibiting DNA duplication, RNA transcription, and protein biosynthesis; influencing or inhibiting enzyme activities; destructing the bacterial cell surface structure and resulting in Ca2+ and K+ released from cells. All of the berberine bactericidal mechanisms are the most essential physiological functions for a live cell, if influenced any one such function, the mutation would be lethal mutation, so that it is difficult to get berberine resistant cells. The results in this paper also prefigure that berberine and its related Chinese medicines would provide a feasible way to control antibiotic resistance problem.
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Aim To assay the mutagenicity of Enphorbia lunulata(EL) decoction and to modify the Ames test for evaluation the mutagenicity of herbal medicine samples.Method The mutagenicity of EL decoction was assayed by standard Ames test; the teratogenicity was done by mammalian bone marrow chromosomal aberration test. In modified Ames test system,the influence of histidine EL decoction was excluded by additional negative control, in which the test media was supplied with histidine (histidine amount equaled to the histidine in different concentration of EL decoction).Result The mutagenicity of EL decoction was positive in the standard Ames test. The teratogenicity of EL decoction was negative in mammalian bone marrow chromosomal aberration test. By the modified Ames tests,the mutagenicity of EL decoction was negative.Conclusion The standard Ames test is not suitable for evaluating the mutagenicity of EL decoction, but the modified Ames test is. The mutagenicity in vitro and the teratogenicity in vivo of EL decoction are all negative.
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AIM Objective By comparing E.coli's resistance to antibiotics and Chinese medical herbs before and after incubated in LB containing Neomycin or Chinese medical herbs, we try to understand the difference in their mechanism of resistance. METHODS We incubated E.coli cells under the culturing media with low concentration of Neomycin and Chinese medicine herbs respectively; lately, the culturing process were continued under the media with no Neomycin or Chinese medicine herbs. We tested the minimal inhibitory concentrations(MIC)of Neomycin(Kanamycin, Gentamicin, Tetracyclin etc) and Chinese medical herbs to culture cells. Result The experimental data indicated that increased resistance of population cells in the broth including Neomycin happened easily, as well as multi resistance simultaneously. As for the Chinese medical herbs, the case is different. After growing in the LB containing one of Huang Lian (rhizoma coptidis), Berberine or San-Huang-Tang of low concentrations, population cells did not increase their resistance either to antibiotics or to Chinese medical herbs. Removing the pressure of Neomycin, E.coli population cells resistance came back to the initial level. CONCLUSION The increased antibiotic resistance of population cells is unstable, and alternative using of different antibiotics maybe contribute to the alleviation of antibiotics resistance.