Effect of filamentation and mode of growth on antifungal susceptibility of Candida albicans

Biofilm formation involving profuse hyphal growth is a major characteristic of Candida spp. and confers higher antifungal resistance than its planktonic mode of growth. We investigated the antifungal susceptibility of Candida albicans and its hyphal mutants (Δefg1/efg1, Δcph1/cph1 and ΔΔcph1/cph1 efg1/efg1) to commonly used antifungals during planktonic, adhesion and biofilm modes of growth. The minimum inhibitory concentration (MIC) of each antifungal agent was determined for a lower inoculum (1 × 10³ cells/mL) and higher inoculum (1 × 10⁷ cells/mL) of planktonic Candida. Furthermore, MICs of C. albicans biofilms and adhesion modes of growth were determined with a standard XTT assay. Candida albicans in adhesion and biofilm modes of growth, but not in planktonic mode, were resistant to all five antifungal agents tested. Although Δefg1/efg1 and ΔΔcph1/cph1 efg1/efg1 mutants formed less biofilm than wild-type C. albicans SC5314, they were similarly resistant to caspofungin. However, these mutants were more sensitive to amphotericin B and nystatin than the wild-type. Adhesion per se confers increased resistance to antifungal agents, which is further pronounced in the biofilm mode of Candida. Filamentation does not appear to be a major determinant of the antifungal resistance in Candida biofilms.     

Metronidazole and clarithromycin resistance amongst Helicobacter pylori isolates from a large metropolitan hospital in the United States

Background: Metronidazole and clarithromycin-based therapies are among the most efficacious treatment regimens for H. pylori infection. Resistance to metronidazole or clarithromycin is associated with impaired therapy with these agents. We conducted a retrospective review of susceptibility data to determine the frequency of primary metronidazole and clarithromycin resistance among H. pylori isolates from a single metropolitan hospital in the United States. The database comprised 933 patients who presented at the Digestive Diseases Clinic at the Veterans Affairs Medical Center in Houston between September 1988 and January 1997 with complaints of dyspepsia, abdominal pain and peptic ulcer disease. One hundred and seventy-nine of these patients had both pharmaceutical records available for evaluation and culture and antimicrobial susceptibility data for analysis. The MICs were determined by both E-test and broth microdilution tests. The frequency of primary metronidazole resistance was 37.4% (67/179). The level of primary clarithromycin resistance was 6.1%. Dual metronidazole and clarithromycin resistance was present in approx. 3%. The high level of primary metronidazole and clarithromycin resistance in H. pylori isolates from this metropolitan hospital is such that antimicrobial susceptibility data should be available so that informed choice can be made for specific eradication therapies, especially in patients who fail treatment.     

15个产地玄参中哈巴苷与哈巴俄苷含量测定

目的 建立HPLC法同时测定玄参中哈巴苷、哈巴俄苷的含量.方法 采用HPLC-PDA法测定,固定相采用Eclipse Plus C18色谱柱,以乙腈–0.03％磷酸水溶液为流动相,梯度洗脱;体积流量1.0 ml/min;检测波长210、280 nm.结果 哈巴苷、哈巴俄苷分别在0.1020～0.5100 mg/ml(r...     

In vitro susceptibility of Burkholderia pseudomallei to antimicrobial peptides

Burkholderia pseudomallei, the causative agent of melioidosis, is intrinsically resistant to many antibiotics, resulting in high mortality rates of 19% in Australia and even 50% in Thailand. Antimicrobial peptides (AMPs) possess potent broad-spectrum bactericidal activities and are regarded as promising therapeutic alternatives in the fight against resistant microorganisms. Moreover, these peptides may also affect inflammation, immune activation and wound healing. In this study, the in vitro activities of 10 AMPs, including histatin 5 and histatin variants, human cathelicidin peptide LL-37 and lactoferrin peptides, against 24 isolates of B. pseudomallei were investigated. The results showed that the antibacterial activities of the individual peptides depended on peptide dose and bacterial isolate. Among the 10 peptides tested, LL-37 exhibited the most effective killing activity. The smooth type A lipopolysaccharide (LPS) phenotype B. pseudomallei appeared to be more susceptible than those expressing the smooth type B LPS and the rough type LPS. Four isolates of B. pseudomallei shown to be resistant to ceftazidime and trimethoprim/sulfamethoxazole were also highly susceptible to LL-37. These data indicate that LL-37 possesses antimicrobial activity against all isolates independent of the LPS phenotype and is therefore a promising peptide to combat B. pseudomallei infections.     

In vitro antimicrobial activity of a chitooligosaccharide mixture against Actinobacillus actinomycetemcomitans and Streptococcus mutans

The purpose of this study was to evaluate the in vitro antibacterial activity of a chitooligosaccharide mixture (MW 2000–30 000 Da) with a deacetylation degree of 91.5% against two representative oral pathogens, Actinobacillus actinomycetemcomitans and Streptococcus mutans. A 0.1% concentration of the chitooligosaccharides (derived from the exoskeletons of marine crustaceans) was used to estimate antibacterial activity. Approximately 2 log colony forming units (CFU)/ml of A. actinomycetemcomitans were inactivated by 0.1% chitosan after 30 min, while 120 min exposure inactivated about 4.5 log CFU/ml of this organism. In contrast, the level of inactivation against S. mutans was less than 0.5 log CFU/ml after an exposure of up to 120 min. Electron microscopy showed that the exposure of A. actinomycetemcomitans to the chitooligosaccharides resulted in the disruption of cell membranes and that it could be considered for the treatment of periodontal diseases associated with A. actinomycetemcomitans.     

大黄、枳实、厚朴不同炮制品对小承气汤中药效组分的影响

目的研究大黄、枳实、厚朴饮片变化对小承气汤药效组分的影响,以期为临床的合理应用和饮片的质量标准提供参考。方法采用HPLC法分别测定各类成分。大黄游离蒽醌类(芦荟大黄素、大黄酸、大黄素、大黄酚、大黄素甲醚):Syncronis C_(18)色谱柱(250 mm×4.6 mm,5μm);流动相:甲醇–0.1%磷酸;梯度洗脱;体积流量0.8 m L/min;柱温30℃;进样量10μL;检测波长254 nm。大黄结合蒽醌类(番泻苷B、番泻苷A):Syncronis C_(18)色谱柱(250 mm×4.6 mm,5μm);流动相:乙腈–0.05%磷酸;梯度洗脱;柱温30℃;进样量10μL;检测波长340 nm。枳实黄酮苷类(芸香柚皮苷、柚皮苷、橙皮苷、新橙皮苷):Syncronis C_(18)色谱柱(250 mm×4.6 mm,5μm);流动相:乙腈–水;梯度洗脱;体积流量0.7 m L/min;柱温40℃;进样量10μL;检测波长283 nm。厚朴木脂素类成分(和厚朴酚、厚朴酚):Syncronis C_(18)色谱柱(250 mm×4.6mm,5μm);流动相:乙腈–0.05%磷酸;梯度洗脱;体积流量0.7 m L/min;柱温30℃;进样量10μL;检测波长294 nm。结果小承气汤配伍剂量(大黄12 g–炒枳实9 g–姜厚朴6 g)不变,大黄、枳实、厚朴饮片改变时,小承气汤药效组分总量变化规律为:大黄–枳实–姜厚朴酒大黄–炒枳实–姜厚朴熟大黄–炒枳实–姜厚朴大黄炭–炒枳实–姜厚朴≈小承气汤大黄–炒枳实–厚朴,变化率分别为酒大黄组(6.561%)、熟大黄组(4.222%)、大黄炭组(0.118%)、枳实组(30.186%)、厚朴组(-11.218%)。除大黄炭组外,其余组的药效组分总量皆明显变化,其中枳实组变化最明显。结论同一味药材的不同炮制品在小承气汤处方中药效组分不同,对其他药味的影响亦不同,在小承气汤处方配伍中不可随意替代。     

UPLC同时测定不同产地三叶青不同部位中的7种活性成分

目的 建立UPLC同时测定不同产地三叶青不同部位中7种活性成分含量。方法 采用UPLC分离检测,色谱柱为BEH Shield RP18(150 mm×2.1 mm,1.7 μm);柱温35 ℃;进样量2 μL;流动相：乙腈(A)-0.1%磷酸水溶液(B),梯度洗脱;流速0.3 mL·min^-1;检测波长为360 nm和280 nm,采用外标法测定7种活性成分的含量。结果 儿茶素、原花青素B1、芦丁、异槲皮素、山奈酚-3-O-芸香糖苷、紫云英苷、芹菜素分别在1.02~40.8,1.43~57.0,1.16~46.2,1.09~43.6,1.12~44.6,1.18~47.2,0.30~11.8 μg·mL^–1呈良好的线性关系。不同产地三叶青和不同部位三叶青中各成分含量均有一定差异。结论 采用UPLC同时测定三叶青中7种活性成分准确可行,为三叶青药材的质量控制提供了参考。     

Another look at differences in the susceptibility of Escherichia coli and Klebsiella pneumoniae to cephalothin and cefazolin

The significance of in vitro susceptibility tests on Enterobacteriaceae to cephalothin and cefazolin has not been exactly defined in the guidelines of the National Committee for Clinical Laboratory Standards. In the hope of clarifying this confusion, we provide additional information from an ancillary study of the Taiwan Surveillance of Antimicrobial Resistance 1998 (TSAR I). There were 505 Escherichia coli and 227 Klebsiella pneumoniae isolates susceptible to cephalothin, reported by 42 participating hospitals. The susceptibility of these isolates were re-tested at the Microbial Infections Reference Laboratory using cefazolin, with the result that 72% of the 252 cephalothin-resistant E. coli isolates and 24% of the 41 cephalothin-resistant K. pneumoniae isolates were found to be susceptible to cefazolin. We further surveyed the availability of cephalothin and cefazolin in Pharmacy Departments; all of the TSAR I hospitals had cefazolin available in their pharmacies. The resistance rate of E. coli was significantly lower for 12 hospitals that had cefazolin in both pharmacy and laboratory compared with 11 hospitals that had cefazolin available in pharmacy but cephalothin in laboratory. In addition, for all the hospitals that had cephalothin available for clinical use, the resistance rate was twice as low in two hospitals reporting cefazolin susceptibility as in the seven hospitals reporting cephalothin susceptibility. Our findings suggest that inappropriate selection of cephalothin and cefazolin for susceptibility testing contribute to inaccurate indications of in vivo activity for first generation cephalosporins in the treatment of E. coli infections.     

生川乌瓜蒌不同配伍中乌头类生物碱在大鼠体内的药动学研究

目的考察生川乌瓜蒌不同配伍比例醇提液中乌头类生物碱在大鼠体内的药动学研究,比较瓜蒌对其药动学行为的影响。方法建立灵敏、专属、快速的测定大鼠血浆中6种乌头类生物碱的液相色谱-串联质谱方法。大鼠随机分为3组,分别ig生川乌与瓜蒌1∶0、6∶1、1∶6配伍醇提液,在不同的时间点采血分析,经DAS 2.0软件计算主要药动学参数。结果乌头碱、次乌头碱、新乌头碱的药动学参数tmax和t1/2发生了显著变化,且变化趋势基本一致,在生川乌与瓜蒌6∶1配伍组tmax显著减小(P0.05),生川乌与瓜蒌1∶6配伍组tmax显著增加(P0.01、0.001),且t_(1/2)显著降低(P0.05、0.01),提示生川乌与瓜蒌不同配伍比例影响了3种生物碱的吸收和消除过程。结论生川乌与瓜蒌配伍影响了乌头类生物碱的药动学过程,配伍比例是其配伍禁忌的重要条件。     

不同地区市售全蝎氯化钠含量的测定

目的 对全国不同地区市售全蝎中氯化钠的含量进行测定.方法 收集了30个省份的138批次全蝎样品.采用建立的振荡提取和滴定法测定全蝎中氯化钠的含量.结果 应用所建立的方法对样品进行定量分析,结果氯化钠溶液浓度在0.204 8~6.404 6 mg·mL-1范围之间呈良好的线性关系.氯化钠的平均加样回收率为100.4%,RSD为0.78%.138批次样品中氯化钠含量在2.55%~39.86%之间.结论 所建立的氯化钠测定方法操作简便,重现性好,结果准确可靠,可用于全蝎中氯化钠含量的快速检测.市售全蝎中氯化钠含量差异较大,存在超量掺盐问题,有必要加强全蝎的市场监管,以保证临床用药的安全性.     

Detection of lfrA and tap efflux pump genes among clinical isolates of non-pigmented rapidly growing mycobacteria

This study was performed to detect LfrA and Tap efflux pumps among clinical isolates of non-pigmented rapidly growing mycobacteria (NPRGM). Gene detection was performed using polymerase chain reaction (PCR) with specific primers designed for each gene. Susceptibility of the strains to doxycycline, tigecycline and ciprofloxacin was analysed using the broth microdilution reference technique. In total, 166 clinical isolates were included in the study. The lfrA gene was detected in four strains (2.4%), comprising two strains of Mycobacterium chelonae (6.7% of this species), one Mycobacterium fortuitum (1.1%) and one Mycobacterium mucogenicum (14.3%). The tap gene was detected in 109 strains (65.7%), comprising 3 Mycobacterium abscessus (33.3%), 12 M. chelonae (40%), 75 M. fortuitum (84.3%), 2 Mycobacterium mageritense (40%), 15 Mycobacterium peregrinum (68.2%), 1 Mycobacterium alvei and 1 Mycobacterium porcinum; no strains of M. mucogenicum were tap-positive. No differences between tap-positive and -negative strains were observed for resistance to doxycycline (Fisher's exact test, P = 0.055). lfrA is rare among clinical isolates of NPRGM, whilst tap is found more commonly. No correlation was detected between the presence of the efflux pumps and resistance to quinolones or tetracyclines.     

不同来源西洋参药材及产品皂苷成分评价研究

目的 建立测定不同产地西洋参药材及其产品中10 种皂苷成分含量的方法,比较不同来源西洋参中总皂苷及单体皂苷的含量差异,评价品质优劣。方法 采用高效液相色谱法,色谱条件为Thermo Scientific Syncronis C₁₈ 色谱柱(100 mm×2.1mm,1.7 μm),流动相为乙腈-水,二元梯度洗脱,体积流量为0.2 mL/min,检测波长为203 nm,柱温为35 ℃。结果 人参皂苷Rg₁、Re、Rb₁、Rc、Rb₂、Rd、F₁、R₀、F₂、Rk₁ 分别在线性范围内存在良好的线性关系,48 h 内稳定性试验RSD 值均小于5%,平均加样回收率为96%～102%,RSD 值均< 2.21%。结论 该方法准确、快速、灵敏,重复性好,可用于西洋参药材、饮片及相关产品中皂苷的定量分析。不同来源西洋参及其产品中皂苷成分的种类相似,但单体皂苷的含量差异显著,所测样品均不含有人参皂苷Rf,排除掺假。     

Toxicity and gastric tolerance of essential oils from Cymbopogon citratus, Ocimum gratissimum and Ocimum basilicum in Wistar rats

Oils of Cymbopogon citratus, Ocimum gratissimum and Ocimum basilicum are widely used for their medicinal properties, and as food flavours and perfumes. Recently in a study in West Africa, these oils have been recommended to combat Fusarium verticillioides and subsequent fumonisin contamination in stored maize, but their toxicological profile was not investigated. The current study was undertaken to provide data on acute and subacute toxicity as well as on gastric tolerance of these oils in rat. For this purpose, the oils were given by gavage to Wistar rats for 14 consecutive days. The animals were observed daily for their general behaviour and survival, and their visceral organs such as stomach and liver were taken after sacrifice for histological analyses. A dose-dependent effect of the tested oils was observed during the study. Applied at doses generally higher than 1500 mg/kg body weight, the oils caused significant functional damages to stomach and liver of rat. Unlike the other oils, administration of O. gratissimum oil did not result in adverse effects in rat liver at the tested doses. The no observed adverse effect level (NOAEL) of the tested oils has been established. The three tested oils can be considered as safe to human when applied on stored maize at recommended concentrations.     

不同产地细辛中挥发油GC-MS指纹图谱的建立及其化学模式识别研究

目的 建立不同产地细辛药材挥发油的气相色谱-质谱联用(GC-MS)指纹图谱,并结合化学模式识别进行评价。方法 采用GC-MS法建立细辛挥发油的指纹图谱,进行相似度评价,并通过聚类分析(CA)、主成分分析(PCA)、正交偏最小二乘法(OPLS-DA)判别分析不同产地细辛挥发油的质量差异。结果 建立了细辛挥发油的GC-MS指纹图谱,确认24个共有峰,并指认了其中10个共有峰。不同批次细辛挥发油样品相似度在0.908以上。CA、PCA和OPLS-DA结果显示细辛挥发油存在一定的质量差异,以变量投影重要度(VIP)值>1.0为标准,筛选出8个差异性标志成分。结论 GC-MS指纹图谱结合化学模式识别可以全面、系统地评价细辛挥发油的质量特征,为细辛药材的质量评价提供参考。     

梅花鹿鹿茸和马鹿鹿茸中5种核苷类成分的含量比较

目的 建立HPLC测定梅花鹿鹿茸和马鹿鹿茸药材中尿嘧啶、次黄嘌呤、尿苷、鸟苷和肌苷5种核苷成分含量的方法,并比较不同批次的梅花鹿鹿茸和马鹿鹿茸药材中5种核苷类成分含量的差异。方法 采用HPLC对15批梅花鹿鹿茸药材和15批马鹿鹿茸药材进行测定,并对测定结果进行聚类分析。结果 测定了梅花鹿鹿茸和马鹿鹿茸药材中5种核苷类成分的含量,二者中核苷类成分含量差异显著;不同产地不同养殖户的鹿茸药材中,5种核苷成分含量也存在明显差异。采用聚类分析能将不同产地的15批梅花鹿鹿茸和15批马鹿鹿茸药材分为2类。结论 不同产地梅花鹿鹿茸和马鹿鹿茸药材核苷成分的组成存在显著性差异,鹿茸药材的质量受鹿的品种、自然环境、养殖技术等因素的影响。该方法适用于梅花鹿鹿茸和马鹿鹿茸中核苷类成分的含量测定,为二者质量控制提供保证。     

不同产地桑白皮HPLC的指纹图谱的研究

目的 建立简单可行的桑白皮药材指纹图谱方法.方法 采用高效液相色谱法,Agilent Extend-C18(4.6 mm×250 mm,5μm)色谱柱,流动相:以乙腈-0.2%甲酸进行梯度洗脱,流速:1 mL·min-1,柱温:30℃,检测波长:280 nm,进样量为10μL.结果 用梯度洗脱得到的色谱图中各色谱峰分离较好,达到指纹图谱分析的效果.结论 该方法重复性好、检测方法简便,可为桑白皮指纹图谱的质量控制提供依据.     

UPLC-MS/MS法测定不同产地延胡索中原阿片碱、盐酸巴马汀、脱氢紫堇碱、延胡索乙素和延胡索甲素

目的 建立UPLC-MS/MS法同时测定不同产地延胡索药材中原阿片碱、盐酸巴马汀、脱氢紫堇碱、延胡索乙素和延胡索甲素。方法 采用Waters UPLC HSS T3 C18色谱柱（100 mm×2.1 mm,1.7μm）,以乙腈–0.1%醋酸铵为流动相,梯度洗脱,体积流量0.3 mL/min,柱温40℃,进样量5μL。ESI正离子模式采集,采集模式：MRM（多反应检测）,离子源温度150℃,毛细管电压3.0 kV,锥孔电压50 V,脱溶剂气流量800 L/h,脱溶剂气温度400℃。结果 原阿片碱、盐酸巴马汀、脱氢紫堇碱、延胡索乙素和延胡索甲素分别在0.20～10.12、0.25～12.58、1.02～51.20、0.85～42.64、0.39～19.44 ng线性关系良好;平均回收率分别为97.48%、100.16%、101.61%、96.05%、104.17%,RSD值分别为1.70%、2.05%、2.55%、0.74%、3.24%。不同产地的延胡索药材中5种生物碱的含量有明显差异,浙江产地延胡索药材中5种生物碱的含量相对其他产地较高,5种生物碱中脱氢紫堇碱的含量最高。结论 UPLC...     

栝楼不同药用部位多糖成分研究进展

中药多糖具有抗氧化、抗病毒、抗肿瘤、抗衰老、降血糖、降血脂、增强免疫等多种药理作用,是中药发挥临床疗效的重要组分之一。栝楼多个部位可供药用,如其果实为瓜蒌、果皮为瓜蒌皮、种子为瓜蒌子、根为天花粉,临床应用广泛。栝楼各部位多糖成分含量丰富,但由于药用部位不同,多糖的提取方法有所差异,再者不同部位所含多糖结构及药理作用也不尽相同。故此文针对瓜蒌多糖、瓜蒌皮多糖、瓜蒌子多糖和天花粉多糖的提取方法、结构特征及药理作用进行综述,以期为栝楼各药用部位多糖成分的开发与利用提供参考。