Design and validation of a multi-electrode bioimpedance system for enhancing spatial resolution of cellular impedance studies
ANALYST
Authors: Alexander, Frank A., Jr.; Celestin, Michael; Price, Dorielle T.; Nanjundan, Meera; Bhansali, Shekhar
Abstract
This paper reports the design and evaluation of a multi-electrode design that improves upon the statistical significance and spatial resolution of cellular impedance data measured using commercial electric cell-substrate impedance sensing (ECIS) systems. By evaluating cellular impedance using eight independent sensing electrodes, position-dependent impedance measurements can be recorded across the device and compare commonly used equivalent circuit and mathematical models for extraction of cell parameters. Data from the 8-electrode device was compared to data taken from commercial electric cell-substrate impedance sensing (ECIS) system by deriving a relationship between equivalent circuit and mathematically modelled parameters. The impedance systems were evaluated and compared by investigating the effects of arsenic trioxide (As2O3), a well-established chemotherapeutic agent, on ovarian cancer cells. Impedance spectroscopy, a non-destructive, label-free technique, was used to continuously measure the frequency-dependent cellular properties, without adversely affecting the cells. The importance of multiple measurements within a cell culture was demonstrated; and the data illustrated that the non-uniform response of cells within a culture required redundant measurements in order to obtain statistically significant data, especially for drug discovery applications. Also, a correlation between equivalent circuit modelling and mathematically modelled parameters was derived, allowing data to be compared across different modelling techniques.
Chromosomal localization of seven HSA3q13 -> q23 Notl linking clones on chicken microchromosomes: orthology of GGA14 and GGA15 to a gene-rich region of HSA3
CYTOGENETIC AND GENOME RESEARCH
Authors: Sazanov, AA; Sazanova, AL; Stekol'nikova, VA; Kozyreva, AA; Romanov, MN; Malewski, T; Smirnov, AF
Abstract
Double-color fluorescence in situ hybridization was performed on chicken chromosomes using seven unique clones from the human chromosome 3-specific Nod linking libraries. Six of them (NL1-097, NL2-092, NL2-230, NLM-007, NLM-118, and NLM-196) were located on the same chicken microchromosome and NL1-290 on another. Two chicken microchromosome GGA15-specific BAC clones, JE024F14 containing the IGVPS gene and JE020G17 containing the ALDH1A1 gene, were cytogenetically mapped to the same microchromosome that carried the six NotI linking clones, allowing identification of this chromosome as GGA 15. Two GGA14-specific clones, JE027C23 and JE014EO8 containing the HBA gene cluster, were co-localized on the same microchromosome as NL1-290, suggesting that this chromosome was GGA 14. The results indicated that the human chromosomal region HSA3q 13 -> q23 is likely to be orthologous to GGA15 and GGA14. The breakpoint of evolutionary conservation of human and chicken chromosomes was detected on HSA3q1 3.3 -> q23 between NL1-290, on the one hand, and six other NotI clones, on the other hand. Considering the available chicken-human comparative mapping data, another breakpoint appears to exist between the above NotI loci and four other genes, TFRC, EIF4A2, SKIL and DHX36 located on HSA3q24 -> qter and GGA9. Based on human sequences within the NotI clones, localization of the six new chicken coding sequences orthologous to the human/rodent genes was suggested to be on GGA15 and one on GGA14. Microchromosomal location of seven NotI clones from the HSA3q21 T-band region can be considered as evidence in support of our hypothesis about the functional analogy of mammalian T-bands and avian microchromosomes. Copyright (c) 2005 S. Karger AG, Basel.