Study on droplet microfluidic chips for drug screening against Candida albicans / 药学学报

A droplet microfluidic chip system was developed for drug screening against Candida albicans. The microfluidic chip was designed and prepared for the formation of droplets. Alamar blue was selected as an indicator for its characteristic of fluorescence mission in live cells. Four antifungal drugs (amphotericin B, caspofungin, 5-fluorocytosine, terbinafine) and a new drug (iodiconazole) were selected as model drugs to test the microfluidic chip approach. At the same time, 96-well microplate method was performed to verify the applicability of the chip method. The results showed that the developed droplet microfluidic chip platform was able to complete the antifungal susceptibility test within 2 h. In comparison with the 96-well microplate method, the microfluidic chip method showed a consistence of 100% with regard to the minimum inhibition concentrations and less reagent consumption. The new droplet microfluidic chip method is simple, rapid and suitable for rapid screening of antifungal drugs.

Assessment of the Activity of Selected Indian Medicinal Plants against Mycobacterium tuberculosis: A Preliminary Screening Using the Microplate Alamar Blue Assay.

Aim: Identification of anti-Mycobacterium tuberculosis agents of plant origin, against sensitive and multidrug resistant (MDR) strains. Study Design: Assessing anti-M. tuberculosis activity of five Indian medicinal plants, which have been reported in traditional literature for various uses including respiratory ailments. Place and Duration of Study: Mumbai, India; May 2009 – December 2011. Methodology of Study: The reference strain (H37Rv), three susceptible and three MDR clinical isolates of M. tuberculosis were used. Acetone, ethanol and aqueous extracts (prepared sequentially) of Acorus calamus L. (rhizome), Andrographis paniculata Nees. (leaf), Ocimum sanctum L. (leaf), Piper nigrum L. (seed) and Pueraria tuberosa DC. (tuber) were tested at 1, 10 and 100 μg/ml using the Microplate Alamar Blue Assay. The active extracts were assessed for cytotoxicity on the human lung epithelial cell line (A549) using the neutral red assay and a phytochemical analysis was made using High Performance Thin Layer Chromatography (HPTLC). Results: Among the plants tested, the acetone extract of P. nigrum appears promising. It was effective against H37Rv, all susceptible isolates and one MDR isolate at 100 μg/ml. The ethanol extract caused some inhibition of growth, though less than the cut-off of 99%. A combination of acetone and ethanol extracts at 50 μg/ml each was effective against all isolates tested. The known active phytoconstituent of P. nigrum, piperine (also an efflux pump inhibitor), was effective against H37Rv in the presence of suboptimal concentration of Rifampicin, but not against the clinical isolates tested. Presence of piperine in the acetone and ethanol extracts was confirmed by HPTLC. Extracts of P. nigrum and piperine were not cytotoxic to the A549 cell line. Conclusion: Amongst the five plants tested, P. nigrum was active. The acetone extract may have active components in addition to piperine. It is possible that the class and expression of efflux pumps in H37Rv is different from that in the clinical isolates, and hence piperine did not inhibit these isolates. Thus, it is necessary to screen clinical isolates in addition to reference strains. The observation of the increased efficacy of the combination of acetone and ethanol extracts is interesting.

Comparison of the activities of amphotericin B, itraconazole, and voriconazole against clinical and environmental isolates of Aspergillus species.

Background: Invasive fungal infections are a significant cause of morbidity and mortality in immunocompromised populations. Aims: To evaluate the susceptibility pattern of our isolates against amphotericin B, itraconazole, and voriconazole and to compare the antifungal activities of these agents with each other against the Aspergillus species tested. Settings and Design: A prospective study was designed to include clinical and environmental isolates of Aspergillus species. Materials and Methods: 420 sputum samples, 70 bronchoalveolar lavage fluids, 160 oral washings, and 47 environmental samples were collected. Direct microscopy by potassium hydroxide and lactophenol cotton blue mounts followed by culture on Sabourad`s dextrose agar (SDA) was done. Susceptibility testing was performed by the broth microdilution technique as per Clinical Laboratory Standards Institute standards (M-38A). Additionally, all the isolates were also tested by the colorimetric microdilution technique using Alamar Blue dye. Statistical Analysis: It was done by the Chi-square test and Z-test using SPSS statistical software version 12.0. Results and Conclusion: Twenty-seven isolates (47.3%) were recovered from patients with chronic bronchial asthma followed by fibrocavitary pulmonary tuberculosis in 9 (15.7%), allergic bronchopulmonary aspergillosis (ABPA) in 6 cases (10.5%), bronchiectasis in 3 (5.2%), bronchogenic carcinoma in 5 (8.7%) and those receiving radiotherapy for head and neck cancer 7 (12.2%). Thirteen environmental isolates were also included in the study. The most common isolate was A. fumigatus 28 (40%), followed by A. niger 22 (31%), A. flavus 13 (19%), and A. terreus 7(10%). All isolates were susceptible to amphotericin B, itraconazole, and voriconazole. Among the three agents tested, voriconazole exhibited lowest MICs (≤1 μg/ml) against all Aspergillus species.

In Vitro Cytotoxicity of Polyphosphoester as a Novel Injectable Alveolar Replacement Material / 华中科技大学学报（医学）（英德文版）

Summary: The aim of this study was to investigate the in vitro cytotoxieity of polyphosphoester polymer used as a novel injectable alveolar bone substitutes for controlled delivery of tetracycline. Cell culture medium was exposed to the polymer (0.01-10 mg/mL) for 24h. The L-929 mouse fibroblasts were then exposed to the treated cell culture medium for 24h. Finally, cell viability and growth were assessed by using MTT assay and Alamar Blue assay. No significant cytotoxicity of the polyphosphoester against L-929 mouse fibroblasts was observed at a concentration up to 10 mg/mL (P0.05). The two evaluation methods showed no significant differences (P0.05). This study suggests that polyphosphoester does not demonstrate any significant toxic effects to cells in vitro and has the potential to be used both as a medical device and as scaffolds in tissue engineering applications.