Non-contact micro-cantilevers detect photothermally induced vibrations that can segregate different categories of exfoliative cervical cytology

We implemented a non-contact photo-thermo-mechanical recording method whereby a silicon nitride atomic force microscopy cantilever is placed several micrometer above the surface of samples. Samples were illuminated with infrared (IR) radiation after which, cantilever mechanical vibrations were optically sensed. Following spectrometric acquisition and Fourier transformation, true IR absorption spectra were obtained. With multivariate analysis, segregation between different categories of exfoliative cervical cytology was obtained. This approach points towards the implementation of a novel near-field system that allows IR spectral analysis without probe contamination.     

Investigation of the antigen antibody reaction between anti-bovine serum albumin (a-BSA) and bovine serum albumin (BSA) using piezoresistive microcantilever based sensors

A new microsensor application based on piezoresistive microcantilever technology has been used to study the interaction of anti-bovine serum albumin (a-BSA) with bovine serum albumin (BSA). A thin layer of BSA attached to a glass slide was used as the active sensing layer for the detection of a-BSA in solution. This design produced a large, consistent cantilever deflection when exposed to the analyte. In this system, the cantilever deflection is measured as a simple resistance change in the piezoresistive channel within the cantilever. In a second set of experiments, 3:1 BSA:PEO protein/polymer blended substrates were used as the active sensing layer for the detection of a-BSA in an aerosol delivery. A distinct signature for the analyte, separate from the water vapor carrier, is obtained for this system.     

Adhesion forces measured between a calcium blocker drug and its receptor in living cells using atomic force microscope

The adhesion force between the tip of an atomic force microscope cantilever derivatized with nimodipine (a calcium blocker, from the dihydropyridine class, currently used in clinical medicine for hypertension) and living cells of Saccharomyces cerevisiae (unicellular eukaryotes which portray ultrastructural features characteristic of higher eukaryotic cells) was measured. This methodology allowed us to locate (and visualize) pores on the cell surface which may be responsible for calcium transportation in the living cells. The interaction of the cantilever derivatized with the calcium blocker and a pore, which can be a calcium channel, is more intense than a non-derivatized cantilever and the pore. Outside the pore (on the rest of cell surface), a derivatized or a non-derivatized cantilever has the same pattern of adhesion force. The information obtained with this method is very important for the design of new, more potent and less toxic drugs for pharmacological use.     

Shared epitope for monoclonal IR162 between Anisakis simplex larvae and Clonorchis sinensis and cross-reactivity between antigens

IR162 is a rat monoclonal IgE antibody (mAb). In the investigation of rat IgE production, the antigens recognized by IR162 (IR-Ags) were found to be expressed by a variety of helminthic parasites. By western blot analysis, IR162 detected bands in crude extracts of Anisakis simplex larvae, Clonorchis sinensis, Paragonimus westermani, plerocercoids of Spirometra mansoni, and Toxocara canis. Excretory-secretory material from A. simplex larvae also contained a protein recognized by IR162. IR162 mAb obtained from both Serotec and Zymed recognized identical bands of A. simplex larvae. Sandwich enzyme-linked immunosorbent assay analysis indicated that both IR-Ags of A. simplex larvae (IR-As) and C. sinensis (IR-Cs) were important antigens with respect to induction of specific IgG in human infections with these 2 organisms. Even though minimal cross-reaction between IR-As and IR-Cs was observed using sera from infected individuals, these results indicate that IR-Ags are found in the parasites examined, that IR-As and IR-Cs are the antigens that induce specific antibody in natural infection, and that the epitope that binds IR162 is shared by A. simplex larvae and C. sinensis.     

Finite element analysis of implant-supported prosthesis with pontic and cantilever in the posterior maxilla

The aim of this study was to evaluate the influence of pontic and cantilever designs (mesial and distal) on 3-unit implant-retained prosthesis at maxillary posterior region verifying stress and strain distributions on bone tissue (cortical and trabecular bones) and stress distribution in abutments, implants and fixation screws, under axial and oblique loadings, by 3D finite element analysis. Each model was composed of a bone block presenting right first premolar to the first molar, with three or two external hexagon implants (4.0 × 10 mm), supporting a 3-unit splinted dental fixed dental prosthesis with the variations: M1 – three implants supporting splinted crowns; M2 – two implants supporting prosthesis with central pontic; M3 – two implants supporting prosthesis with mesial cantilever; M4 – two implants supporting prosthesis with distal cantilever. The applied forces were 400 N axial and 200 N oblique. The von Mises criteria was used to evaluate abutments, implants and fixation screws and maximum principal stress and microstrain criteria were used to evaluate the bone tissue. The decrease of the number of implants caused an unfavorable biomechanical behavior for all structures (M2, M3, M4). For two implant-supported prostheses, the use of the central pontic (M2) showed stress and strain distributions more favorable in the analyzed structures. The use of cantilever showed unfavorable biomechanical behavior (M3 and M4), mainly for distal cantilever (M4). The use of three implants presented lower values of stress and strain on the analyzed structures. Among two implant-supported prostheses, prostheses with cantilever showed unfavorable biomechanical behavior in the analyzed structures, especially for distal cantilever.     

Interaction between chondroitin-6-sulfate and Entamoeba histolytica as revealed by force spectroscopy

We have observed by atomic force microscopy (AFM) the amoeba surface and probed the interaction force between Entamoeba histolytica and chondroitin-6-sulphate (C6S). We have used several substrates to adhere trophozoites. The best reproducibility in sample preparation was obtained with fibronectin-coated coverslips and when the cells were fixed with paraformaldehyde. The images obtained with the AFM showed that the trophozoite exhibits an irregular surface. Pseudopods and waving adhesion plaques could be observed. Force spectroscopy analysis showed that the trophozoite surface strongly interacts with C6S-functionalized tips. During cantilever retraction, attractive force peaks were observed at distances up to 1.3 microm above the trophozoite surface. Statistical analysis of the force distributions collected for five samples shown a reproducible 2.2 nN mean adhesion force. We observed a reduction of the adhesion force and of the interaction distance after addition of galactose to the buffer solution suggesting that the observed interaction is also Gal/GalNAc-lectin-mediated.     

The comparative study of the IR spectra of proteoglycans]

The IR spectra of sodium salt hyaluronic acid, chondroitin-4-sulfate, chondroitin-6-sulfate, dermatan-sulfate, protein-chondroitin-keratan-sulfate and aggregates of proteoglycans of the hyaline cartilage, heparin fractions containing 3 and 4 residues of sulfuric acid per dimer of polymer were obtained. It was shown that comparative analysis of IR spectra of the proteoglycans makes it possible to identify the 1150 cm-1, 1125 cm-1.     

牛膝多糖衍生物的几种取代度测定方法的探讨

在研究多糖的结构与功能关系时 ,多糖经化学修饰后 ,其取代基的多少和取代位置均对活性有重要的影响 ,因此对于离子型牛膝多糖衍生物和非离子型牛膝多糖衍生物 ,如何准确测定其取代度非常重要。通过运用酸碱滴定法 (ABT)、原子吸收光谱法 (AAS)、傅立叶变换红外光谱法 (FTIR)和高效液相色谱法(HPLC)相对照分别对羧甲基牛膝多糖 (CM Abps)和羟乙基牛膝多糖 (HE Abps)的取代度进行测定 ,实验结果发现在DS <1.0范围内 ,测得CM Abps的几组数值均比较接近 ,且线性关系较好 ;在DS <2 .0范围内 ,测得HE Abps的几组数值均比较接近 ,线性关系也较好。研究表明 ,运用ABT、AAS、FTIR和FTIR相对照测定CM Abps和HE Abps的取代度是切实可行的 ,而且方法快速简捷 ,精确度和重现性较好。     

应用电子散斑干涉术对单端固定桥的受载分析

本文目的是对单端固定桥的运动及其受力状态进行试验性研究。采用电子散斑干涉术这一新的光学技术分别对下颌单端固定桥修复前后进行４种垂直加载测试,观察实时显示的散斑干涉条纹图,并测量相应牙槽骨处的离面位移。     

Mid-IR microspectroscopic imaging of breast tumor tissue sections

IR microspectroscopic imaging is a relatively new approach for the examination of tissue sections. In contrast to standard light microscopy based procedures, the IR approach requires neither sample staining nor fixation. The IR spectra of breast tumor tissue sections are obtained via a microscope equipped with a focal plane array detector. This enabled the simultaneous collection of individual mid-IR spectra from thousands of different sample positions with a spatial resolution near the diffraction limit. The analysis of the IR data reveals a high sensitivity of the IR approach toward changes in tissue biochemistry and variations in breast tissue architecture. Moreover, the data demonstrate the need for collecting spectra with high spatial resolution at the level of individual cells. This minimizes problems associated with tissue microheterogeneity and is an essential prerequisite for future studies aimed at developing IR microspectroscopic imaging as a complement to present diagnostic tools for breast cancer.     

A comparison of techniques for studying oogenesis in the European eel Anguilla anguilla

A multi‐technique approach was used to study the changes occurring in European eel Anguilla anguilla ovaries during hormonally‐induced vitellogenesis. Aside from classic techniques used to monitor the vitellogenic process, such as ovary histology, fat content analysis, sodium dodecyl sulphate–polyacrylamide gel electrophoresis (SDS–PAGE) and vitellogenin enzyme linked immunosorbent assay (ELISA), a new technique, Fourier‐transform infrared (FT‐IR) microspectroscopy, was used to analyse A. anguilla ovaries. The results from the different techniques provided different ways of approaching the same process. Although it is considered a time consuming approach, of all the employed techniques, histology provided the most direct evidences about vitellogenesis. SDS–PAGE and ELISA were also useful for studying vitellogenesis, whereas fat analysis cannot be used for this purpose. The FT‐IR analysis provided a representative IR spectrum for each ovarian stage (previtellogenic stage, early vitellogenic stage, mid‐vitellogenic stage and late vitellogenic stage), demonstrating that it is a valid method able to illustrate the distribution of the oocytes within the ovary slices. The chemical maps obtained confirmed changes in lipid concentrations and revealed their distribution within the oocytes at different maturational stages. When the results and the accuracy of the FT‐IR analysis were compared with those of the traditional techniques commonly used to establish the vitellogenic stage, it became evident that FT‐IR is a useful and reliable tool, with many advantages, including the fact that it requires little biological material, the costs involved are low, analysis times are short and last but not least, the fact that it offers the possibility of simultaneously analysing various biocomponents of the same oocyte.     

Accurate determination of the structural elasticity of human hair by a small-scale bending test

This paper reports on a small-scale bending method for human hair. The test sample, which is elliptical in cross-section, is fixed to a hollow steel needle using resin to form a cantilever. A loading probe is used to subject this to a lateral load, where the load is applied parallel to either the long or short axis of the elliptical cross-section. From these tests, load-displacement relationships for the hair were obtained. From the experimental data and analysis, we found that the structural elasticity determined is independent of the direction of bending, and precise measurements of the structural elasticity of human hair with scattering of less than 5% were realized using this test scheme. Finally, changes in the structural elasticity of hair due to hair treatments were detected and the changes are discussed based on a theoretical model of the multi-layered structure.     

金针菇子实体多糖分离纯化及结构和免疫活性研究

从金针菇子实体中分离纯化多糖,并对多糖结构和体外免疫活性进行研究。采用水提醇沉法从金针菇子实体中提取粗多糖,利用DEAE-Cellulose-52及Sephacryl S-300HR柱层析纯化得到FVPⅠ-a,再利用HPLC-ELSD技术、红外及核磁共振对FVPⅠ-a进行结构解析。在体外以促RAW264.7巨噬细胞产NO、分泌细胞因子,促进小鼠淋巴细胞增殖实验,考察FVPⅠ-a增强免疫的能力。从金针菇子实体中分离纯化得到FVPⅠ-a,其为分子量81.4kDa,由葡萄糖、果糖和鼠李糖组成的β构型的吡喃型杂多糖。体外免疫实验表明,FVPⅠ-a能够促进RAW264.7巨噬细胞产生NO及分泌细胞因子（IL-1β,IL-6,TNF-α）,能单独的促进小鼠淋巴细胞增殖（P<0.05）,并能协同增强ConA和LPS对小鼠淋巴细胞的促增殖作用（P<0.01,P<0.05）。首次从金针菇子实体中获得FVPⅠ-a杂多糖,其在体外具有增强非特异性免疫反应及增强特异性免疫反应的能力。     

The protective role of postvaccinal immunity in mumps in children

The immunological study of children with infectious parotitis (IP) without complications and with such complications as pancreatitis, meningitis or orchitis in the glandular form was carried out. In accordance with the previously proposed principle, 4 types of immune response (IR) were established on the basis of differences in initial resistance and the IR profile: cell-mediated immunity (types I and III) and humoral immunity (types II and IV). The patients included nonvaccinated children, as well as children vaccinated on epidemic indications, 3-6, 7-9, 10 and more years before infection. The comparative analysis of the number of IP cases with and without complications in the groups of children, divided according to their immunization history and the type of IR, revealed that postvaccinal immunity in children vaccinated on epidemic indications (less than a month ago) or 3-6 years before infection had protective potential, sufficient for the prevention of complicated forms of IP. Immunity obtained 7-9 years ago was effective for the protection from IP complications only in cell-mediated, but not humoral IR. Postvaccinal immunity obtained more than 10 years ago did not ensure the decrease in the occurrence of complicated forms of IP (in comparison with that in nonvaccinated patients) in children with any type of IR.     

Infrared spectroscopy with multivariate analysis potentially facilitates the segregation of different types of prostate cell

The prostate gland is conventionally divided into zones or regions. This morphology is of clinical significance as prostate cancer (CaP) occurs mainly in the peripheral zone (PZ). We obtained tissue sets consisting of paraffin-embedded blocks of cancer-free transition zone (TZ) and PZ and adjacent CaP from patients (n = 6) who had undergone radical retropubic prostatectomy; a seventh tissue set of snap-frozen PZ and TZ was obtained from a CaP-free gland removed after radical cystoprostatectomy. Paraffin-embedded tissue slices were sectioned (10-mum thick) and mounted on suitable windows to facilitate infrared (IR) spectra acquisition before being dewaxed and air dried; cryosections were dessicated on BaF(2) windows. Spectra were collected employing synchrotron Fourier-transform infrared (FTIR) microspectroscopy in transmission mode or attenuated total reflection-FTIR (ATR) spectroscopy. Epithelial cell and stromal IR spectra were subjected to principal component analysis to determine whether wavenumber-absorbance relationships expressed as single points in "hyperspace" might on the basis of multivariate distance reveal biophysical differences between cells in situ in different tissue regions. After spectroscopic analysis, plotted clusters and their loadings curves highlighted marked variation in the spectral region containing DNA/RNA bands ( approximately 1490-1000 cm(-1)). By interrogating the intrinsic dimensionality of IR spectra in this small cohort sample, we found that TZ epithelial cells appeared to align more closely with those of CaP while exhibiting marked structural differences compared to PZ epithelium. IR spectra of PZ stroma also suggested that these cells are structurally more different to CaP than those located in the TZ. Because the PZ exhibits a higher occurrence of CaP, other factors (e.g., hormone exposure) may modulate the growth kinetics of initiated epithelial cells in this region. The results of this pilot study surprisingly indicate that TZ epithelial cells are more likely to exhibit what may be a susceptibility-to-adenocarcinoma spectral signature. Thus, IR spectroscopy on its own may not be sufficient to identify premalignant prostate epithelial cells most likely to progress to CaP.     

Anthracen-derivate in kalluskulturen aus Cassia angustifolia

Callus cultures from cotyledons of Cassia angustifolia were shown to contain dianthrones. Proof of their structures was obtained by co-chromatography (TLC), oxidative cleavage and UV analysis. The basic components chrysophanol, physcion, rheum emodin, aloe emodin and rhein have been isolated and identified by UV and IR analysis.     

Versatile, high-speed force transducer using a laser diode beam as an optical lever.

A force transducer with variable sensitivity and speed is described. Its moving element is a cantilever beam that projects vertically into a muscle bath. A brace constrains bending of the beam to a short, proximal "hinge." Rotation of the beam about the hinge is amplified 30-fold by an optical lever consisting of a laser diode beam reflected from a mirror on the cantilever to a photodiode pair. This design places the electrical components at a distance from the damp environment of the muscle bath. Large changes in sensitivity and speed can be obtained by substituting different cantilevers. Smaller changes can be made by varying the length of the hinge. A transducer with a 6-mm cantilever optimized for the study of single, skinned skeletal muscle fibers is described in detail. This device had a resonant frequency of 22 kHz and sensitivity such that the total root-mean-square noise in the circuit was more than 500-fold smaller than the expected maximum force. Variations of this device with orders of magnitude different sensitivities are also described.     

一种1型单纯庖疹病毒载体系统的建立

1型单纯疱疹病毒（HSV-1）作为溶瘤病毒和病毒载体的研究已有很长的历史. 本研究利用细菌人工染色体技术建立了一种HSV-1载体系统. 首先,将HSV-1内部反向重复序列（internal inverted repeat sequences, IR）两侧的片段克隆入pKO5获得穿梭质粒pKO5/BN,其电转含pHSV-BAC的大肠杆菌后筛选获得删除IR区重组DNA的 pHSVΔIR-BAC. pHSVΔIR-BAC转染Vero细胞获得删除IR区的重组病毒HSVΔIR（MH1001）.上述pKO5/BN和含pHSVΔIR BAC的大肠杆菌构成了HSV-1载体系统. 利用该系统获得了表达绿色荧光蛋白EGFP的重组病毒HSVΔIR/EGFP（MH1002）.MH1001和MH1002在感染的Vero细胞中增殖水平略低于野生型HSV-1,但无显著差异|Western印迹检测表明,重组病毒早期蛋白质ICP0、ICP4、ICP8、ICP22、ICP27在感染细胞中的表达水平下降|免疫荧光及激光共聚焦检测表明,重组病毒与野生型病毒均存在于细胞质中.以上结果表明,删除IR区的重组HSV-1保留了复制能力,能够携载并表达外源基因,建立的HSV-1载体系统可用于构建携载外源基因的复制型重组HSV-1.     

Molecular docking studies of banana flower flavonoids as insulin receptor tyrosine kinase activators as a cure for diabetes mellitus

Diabetes mellitus is a metabolic disorder caused due to insulin deficiency. Banana flower is a rich source of flavonoids that exhibit anti diabetic activity. Insulin receptor is a tetramer that belongs to a family of receptor tyrosine kinases. It contains two alpha subunits that form the extracellular domain and two beta subunits that constitute the intracellular tyrosine kinase domain. Insulin binds to the extracellular region of the receptor and causes conformational changes that lead to the activation of the tyrosine kinase. This leads to autophosphorylation, a step that is crucial in insulin signaling pathway. Hence, compounds that augment insulin receptor tyrosine kinase activity would be useful in the treatment of diabetes mellitus. The 3D structure of IR tyrosine kinase was obtained from PDB database. The list of flavonoids found in banana flower was obtained from USDA database. The structures of the flavonoids were obtained from NCBI Pubchem. Docking analysis of the flavonoids was performed using Autodock 4.0 and Autodock Vina. The results indicate that few of the flavonoids may be potential activators of IR tyrosine kinase.     

Genetic heteroduplex analysis of the R6K plasmid]

The results of genetic studies of R6K Tra1- and R6Kdelta[Sm1] mutants of R6K plasmid and those of heteroduplex analysis of DNAs have shown that DNA of this drug-resistant factor contains three loops flanked by the inverted repeats. The latter are designated as IR1, IR2 and IR3 and are of 50, 100 and 120 nucleotides in size respectively. IR1 is inserted into the loop flanked by IR2. Loops with these two repeats are located in major EcoR1 fragment, IR3 having been found in minor EcoRI fragment of the plasmid. The evidence obtained from the analysis of heteroduplex R6K/RSF2124 has shown that the loop with IR1 is corresponding to transposon Tn3. The extent of the deletion deltaSm1 indicates that IR2 may be a part of a transposon bearing the resistance to streptomycin. By comparing present data with those obtaine from the analysis of the RSF1040 factor of DNA replication initiation sites (Grosa et al., 1976), it has been suggested that the loop with IR3 represents a transposon with replicative functions (TnRep). The deletion of the mutant plasmid R6Kdelta[Sm1] (7.2 . 10(6) daltons in size) which affected one of the EcoRI sites not only confers the sensitivity to streptomycin but enhances also the efficiency of conjugational transfer and results in the loss of the R6K ability to bring about integrative suppression and to inhibit the fertility of the plasmids from IncP and IncN groups. The deletion mutant proved to have lost the property of incompatibility with the initial plasmid R6K and with itself.