Single Conducting Polymer Nanowire Based Sequence‐Specific,Base‐Pair‐Length Dependant Label‐free DNA Sensor

We have fabricated a highly sensitive, simple and label‐free single polypyrrole (Ppy) nanowire based conductometric/chemiresistive DNA sensor. The fabrication was optimized in terms of probe DNA sequence immobilization using a linker molecule and using gold‐thiol interaction. Two resultant sensor designs working on two different sensing mechanisms (gating effect and work function based sensors) were tested to establish reliable sensor architecture with higher sensitivity and device‐to‐device reproducibility. The utility of the work function based configuration was demonstrated by detecting 19 base pair (bp) long breast cancer gene sequence with single nucleotide polymorphism (SNP) discrimination with high sensitivity, lower detection limit of ∼10⁻¹⁶ M and wide dynamic range (∼10⁻¹⁶ to 10⁻¹¹ M) in a small sample volume (30 µL). To further demonstrate the utility of the DNA sensor for detection of target sequences with different number of bases, targets with 21 and 36 bases were detected. These sequences have implications in environmental sample analysis or metagenomics. Sensor response showed increase with the number of bases in the target sequence. For long sequence (with 36 bases), effect of DNA alignment on sensor performance was studied.     

Direct Determination of Mn in Breast Milk by GF AAS After Multivariate Optimization

Abstract

The procedure proposed in this work includes a 50% v/v dilution of breast milk with TRIS (hidroximetilaminometano 80% v/v) or MEA (monoetanolamina 20% v/v) solutions and the introduction of 20 µL samples or analytical solutions in a graphite furnace. The optimization of the instrumental conditions was made using multivariate tools (fractional factorial and central composite design planning). The accuracy was tested with certified reference material (Infant Formulat NIST® 1846) using the optimized conditions for each diluent. The accuracy has only been acceptable when TRIS was used. The method used to determine Mn in breast milk with a limit of detection of 0.28 µg L^?1 and a characteristic mass of 1.9 pg.     

Development and Analytical Validation of a BT-474 Anti-Proliferation Assay Targeting HER2

Human Epidermal Growth Factor Receptor 2 (HER2) is an ideal target for anti-tumor drug development especially for breast cancer. Based on this target, either for new drug, bio-better, bio-similar screening at discovery level, or for drug substance and drug product release at QC or industry level, a reliable and robust biological potency assay is urgently needed. In this study, a BT-474 cell based anti-proliferation biological potency assay targeting HER2 was developed after an optimization of some key aspects, including cell line, seeded cell density, incubation time, and usable method for viable cell staining. Following optimization, the assay was validated to identify its specificity, precision, accuracy, linearity, range, and robustness. It was proven a highly accurate assay with good fit (R² > 0.98), low RSD (even <5%) of replicates, and broad range (50%–150%) and could be used for drug candidates screening and quality control. This study also provides a good example for cell-based biological potency assay development aimed at other targets.     

Gas Liquid Chromatographic Determination of Caffeine in Breast Milk and Blood Plasma

Abstract

An improved procedure for the determination of caffeine in the presence of bupivicaine (internal standard) using gas liquid chromatography with nitrogen phosphorous detection is described. The method is based on the extraction of caffeine from plasma with a mixture of chloroform and isopropanol (95:5). The chloroform and isopropanol mixture is evaporated to dryness and the residue dissolved in 500 μl of ethyl acetate. One to 2 μl samples are injected directly into the gas chromatograph. This extraction process doesn't give rise to troublesome interfering peaks in the chromatogram. The recovery of caffeine from plasma and breast milk is approximately 99.7% and 94.1% respectively. The coefficient variation of the assay from plasma and breast milk is 2.90% and 1.18% respectively. The limit of quantitation is 0.05 mcg/ml of plasma or breast milk. Data are presented to illustrate the practicality of the method for bioavailability and pharmacokinetic evaluation of caffeine plasma and breast milk levels after oral administration of 100 mg of caffeine to lactating mothers.     

用多元分析方法研究乳腺癌血清的表面增强拉曼光谱

借用两种化学计量学分析方法——主成分分析方法(PCA)和判别分析方法(LDA),进行联合运用,分析了乳腺癌血清的表面增强拉曼光谱(SERS)。首先从分子角度上讨论了蛋白质主侧链在乳腺癌血清中变化,结果发现:主链空间结构遭到破坏。侧链的有序性下降、糖质环境也发生了改变;其次采用上述两种计量学的多元分析方法对18例临床确诊为乳腺癌患者和20例健康人的血清样本进行了表面增强拉曼光谱分析。发现主成分分析方法对于样本区分未能达到80%,进而再用判别分析法,准确率达到100%,所得结果令人满意。     

Apoptosis of T-47D Cells Induced by Cinobufacini via a Caspase-3-dependent Manner

To investigate the mechanism of the anti-tumor activity of cinobufacini on the breast cancer cell line T-47D,the inhibitory effect of cinobufacini on the proliferation of T-47D was detected via MTT assay and the morphological changes of T-47D and HBL-100 cells caused by cinobufacini were observed with an inverted microscope.Cell apoptosis and cell cycle stages were detected by flow cytometry analysis.The effects of cinobufacini on the expression of active-form and pro-form of caspase-3 were assessed by Western blot analysis.Cinobufacini dramatically inhibited T-47D proliferation in a dose-and time-dependent manner.We found that more than 20％ of T-47D cells were killed after treatment with 20 mg/mL cinobufacini for 24 h in vitro.After 6 d of treatment with 20 mg/mL cinobufacini,the cell survival rate decreased by more than 40％.Flow cytometric analysis demonstrated that cinobufacini induced significant apoptosis and changes of the cell cycle distribution of T-47D cells.We used breast cell line HBL-100 as the control,the above experiments except cell cycle analysis showed that cinobufacini more obviously induced the apoptosis of T-47D cells than that of HBL-100 cells.Western blot analysis confirmed the protein expression of active caspase-3 increased with increasing the dose of cinobufacini.These results indicate that cinobufacini induces the apoptosis of T-47D cells via the up-regulation of caspase-3.     

Preliminary attempt on maximum likelihood tomosynthesis reconstruction of DEI data

Tomosynthesis is a three-dimension reconstruction method that can remove the effect of superim- position with limited angle projections. It is especially promising in mammography where radiation dose is concerned. In this paper, we propose a maximum likelihood tomosynthesis reconstruction algorithm （ML-TS） on the apparent absorption data of diffraction enhanced imaging （DEI）. The motivation of this contribution is to develop a tomosynthesis algorithm in low-dose or noisy circumstances and make DEI get closer to clinic application. The theoretical statistical models of DEI data in physics are analyzed and the proposed algorithm is validated with the experimental data at the Beijing Synchrotron Radiation Facility （BSRF）. The results of ML-TS have better contrast compared with the well known ＇shift-and-add＇ algorithm and FBP algorithm.     

乳腺组织中核酸的FTIR光谱分析

在物理因素和化学因素的影响下 ,乳腺组织中DNA分子结构发生改变而出现损伤 ,导致碱基结构的诱发变异。研究表明 ,FTIR光谱能够灵敏地反应这种结构变化。通过比较不同类型乳腺疾病组织的FTIR光谱、去卷积光谱和数据分析 ,可以看出正常组织、良性组织以及癌组织在蛋白质、核酸和糖含量方面的差异。通过对不同类型乳腺组织中核酸的提取 ,经FTIR光谱和去卷积光谱分析 ,进一步研究了核酸中碱基结构和含量 ,磷酸盐结构和含量之间的差异。结果表明 :癌变组织中胶原蛋白和核酸含量有明显增加 ,糖蛋白含量逐渐减少 (除粘液癌外 )。提取核酸后的光谱和光谱数据显示 :癌变组织中碱基环鸟嘌呤的氢键化程度增强 ;在自由基·OH攻击下 ,癌组织中碱基环腺嘌呤大多数是以氧化的 8 OH Ade形式而存在 ,由于CN振动增强 ,峰位移向高波数 ,磷酸盐含量增加 ,去卷积后 ,A1 0 80 A1 0 50 数据显示 ,从正常、良性到癌组织 ,PO-2 相对于C—O含量增大。从分子生物学、分子医学角度 ,为研究癌变机理提供重要依据     

人乳腺癌组织的显微拉曼光谱研究

研究了人类正常与癌变乳腺组织的显微拉曼光谱特性。与正常乳腺组织相比,癌变组织的核酸骨架磷酸离子vs(PO^-2)特征谱线由1082移到1097cm^-1、强度加强,位于817cm^-1的RNA主链vs(O-P-O)的谱线强度增加;蛋白质酰胺Ⅰ和酰胺Ⅲ两个特征谱带从1657,1273cm^-1分别位移到1662和1264cm^-1,其中1264cm^-1谱线的宽度和强度均增加,某些氨基酸残基的C—O谱线向高波数位移,色氨酸特征峰1368cm^-1在癌变组织中几乎观察不到;脂类特征谱线减少。上述谱线变化表明,癌变组织中核酸的相对含量增加、主链结构发生变化;蛋白质结构同时呈现α-螺旋、无规卷曲、卢．折叠以及β-回折4种构象特征,其分子间的氢键近乎断裂,蛋白质变得松散和无序,色氨酸残基的吲哚环呈现“暴露式”;脂类含量减少。研究表明,显微拉曼光谱可以为乳腺癌变的生化机理研究以及活体诊断提供有力的实验依据。     

Exact quantification of time signals from magnetic resonance spectroscopy by the fast Padé transform with applications to breast cancer diagnostics

Mathematical modeling via the fast Padé transform (FPT) is applied according to experimental NMR data encoded from (a) normal, non-infiltrated breast tissue, (b) benign pathology (fibroadenoma) and (c) malignant breast tissue. At a partial signal length N _P  = 1500, the FPT provided exact reconstruction of all the input spectral parameters for the time signals corresponding to the normal, benign as well as to the malignant lesions. The converged parametric results remained stable at longer signal lengths. The Padé absorption spectra yielded unequivocal resolution of all the extracted physical metabolites, even of those that were nearly completely overlapping (phosphocholine and phosphoethanolamine at 3.22 ppm). The capacity of the FPT to resolve and precisely quantify the physical resonances as encountered in normal versus benign versus malignant breast is demonstrated. In particular, the FPT unambiguously delineated and quantified diagnostically important metabolites such as lactate, as well as choline, phosphocholine and glycerophosphocholine that are very closely overlapping and may represent MR-retrievable molecular markers of breast cancer. This was achieved by the FPT without any fitting or numerical integration of peak areas. We conclude that these advantages of the FPT could be of definite benefit for breast cancer diagnostics via NMR and that this line of investigation should continue with encoded data from benign and malignant breast tissue, in vitro and in vivo. We anticipate that Padé-optimized MRS will reduce the false positive rates of MR-based modalities and further improve their sensitivity. Once this is achieved, and given that MR entails no ionizing radiation, new possibilities for screening/early detection open up, especially for risk groups, e.g. Padé-optimized MRS could be used with greater surveillance frequency among younger women with high breast cancer risk.