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Reproducible Technique (reproducible + technique)
Selected AbstractsVolatile compounds of original African black and white shea butter from Tchad and CameroonEUROPEAN JOURNAL OF LIPID SCIENCE AND TECHNOLOGY, Issue 7 2006Sabine Krist Abstract Shea butter is used as an edible vegetable fat in many African countries. It can be utilized as a substitute or complete replacement for cocoa butter in various applications and plays an important role in traditional African medicinal practice. Although detection of volatile compounds by solid-phase micro-extraction gas-chromatography mass-spectroscopy (SPME-GC-MS) is a very reliable and reproducible technique, which can be used as an important part of authenticity checking, production monitoring and contamination detection, no published data about volatile compounds of shea butter are available so far. In this investigation, the characteristic volatiles in the headspace of original African shea butter samples were identified by using SPME-capillary-GC coupled to a mass selective detector. Almost 100,different volatile components were identified, e.g. fatty acids, saturated and unsaturated aldehydes and ketones, terpenes, and typical Maillard reaction products such as methylfuranes and pyrazines. Furthermore, the samples have been olfactorily evaluated by a panel of professional flavorists and trained analytical chemists. It can be stated that variations in processing conditions of shea butter result in considerable differences in the composition of headspace volatiles, detected by SPME-GC-MS and human olfaction. [source] Intraspecific variation and population structure of the German cockroach, Blattella germanica, revealed with RFLP analysis of the non-transcribed spacer region of ribosomal DNAMEDICAL AND VETERINARY ENTOMOLOGY, Issue 2 2007D. V. MUKHA Abstract Little information is available on genetic variation within and between populations of pest cockroaches. In this study, intraspecific HindIII polymorphism was investigated in the German cockroach, Blattella germanica (Linnaeus) (Dictyoptera, Blattaria: Blattellidae), using restriction fragment length polymorphisms (RFLP) of the non-transcribed spacer (NTS) region of ribosomal DNA (rDNA). Individual male insects were collected from infestations at three different pig farms. Each population was characterized by HindIII restriction fragment frequencies and haplotype (a particular X-chromosome pattern) frequencies. The inheritance of the X-chromosome HindIII rDNA patterns over 12 generations (3 years) follows Mendelian patterns, and the stability of this polymorphic marker indicates infrequent genetic recombination of variable sites. Although pairwise genetic distance measures were uncorrelated with geographical distance, the pattern of genetic differentiation of the three cockroach populations suggests that human-mediated transport of cockroaches is an important force in shaping the population genetic structure of cockroach infestations, at least at the regional scale of 10,100 km. Sequence variation in the ribosomal NTS is a useful marker, and RFLP of rDNA is a simple, robust and reproducible technique for differentiating recently diverged cockroach populations. [source] Morphometric characterization of murine articular cartilage,Novel application of confocal laser scanning microscopyMICROSCOPY RESEARCH AND TECHNIQUE, Issue 9 2009Kathryn S. Stok Abstract A new technique for characterization of the three-dimensional morphology of murine articular cartilage is proposed. The technique consists of a novel application of confocal laser scanning microscopy (CLSM), where the objective was to develop and validate it for cartilage measurements in murine joints. Murine models are used in arthritis research, because they are well-described for manipulating the disease pathophysiology, facilitating our understanding of the disease, and identifying new targets for therapy. A calibration and reproducibility study was carried out to provide a consistent testing methodology for quantification of murine joints. The proximal tibial condyles from male C57BL/6 mice were scanned using a CLS microscope with an isotropic voxel size of 5.8 ,m. Measurements and analyses were repeated three times on different days, and in a second step the analysis was repeated three times for a single measurement. Calculation of precision errors (coefficient of variation) for cartilage thickness and volume was made. The bias of the system was estimated through comparison with histology. This technique showed good precision, with errors in the repeated analysis ranging from 0.63% (lateral thickness) to 3.48% (medial volume). The repeated analysis alone was robust, with intraclass correlations for the different compartments between 0.918 and 0.991. Measurement bias was corrected by scaling the confocal images to 32% of their width to match histology. CLSM provided a fast and reproducible technique for gathering 3D image data of murine cartilage and will be a valuable tool in understanding the efficacy of arthritis treatments in murine models. Microsc. Res. Tech. 2009. © 2009 Wiley-Liss, Inc. [source] A population analysis of VEGF transgene expression and secretionBIOTECHNOLOGY & BIOENGINEERING, Issue 5 2008Golnaz Karoubi Abstract The induction of therapeutic angiogenesis with gene therapy approaches has received considerable interest and some limited clinical success. A major drawback to this approach is a lack of understanding of the pharmacokinetics of therapeutic protein delivery. This has become increasingly more relevant as recent studies have illustrated a defined therapeutic window for angiogenic protein secretion into the local microenvironment. For cell based gene therapies, with cells widely distributed throughout the tissue, this implies that any individual cell must attain a specific secretion rate to produce a local angiogenic response. Here we report a reproducible technique enabling the study of growth factor secretion from individual cells following transient plasmid transfection. We demonstrate significant variability in single cell vascular endothelial growth factor (VEGF) secretion with the majority of total protein secretion arising from a small subpopulation of transfected cells. We demonstrate that VEGF secretion is linearly correlated to intracellular plasmid copy number and protein secretion does not appear to reach saturation within the cell population. The selection of gene therapy approaches that optimize individual cell secretion profiles may be essential for the development of effective gene therapies. Biotechnol. Bioeng. © 2008 Wiley Periodicals, Inc. [source] | ||||||||||