Home About us Contact
|
Home About us Contact | ||
|
|
||
Single Peak (single + peak)
Selected AbstractsCharacterization of alanyl aminopeptidase from insecticide resistant and susceptible strains of Musca domestica L.ENTOMOLOGICAL RESEARCH, Issue 3 2008Sohail AHMED Abstract To investigate the high activity of intracellular proteases in insecticide resistant strains of Musca domestica L., purification by anion-exchange chromatography and gel filtration of one of the enzymes, alanyl aminopeptidase (Ala AP), in three strains of Musca domestica was carried out. The fractions collected by gel filtration of soluble homogenates of the three strains (571ab, 17bb and Cooper) showed a single peak of Ala AP activity. Partially purified Ala AP of the three strains showed high activity at pH 7.5. The presence or absence of Ca2+ in the assay medium did not produce any difference in activity of Ala AP in the 571ab and Cooper strains, but there was a significant difference in the 17bb strain. The activity of Ala AP in all three strains was essentially unaltered in the presence of inhibitors of serine (PMSF), cysteine (E-64) proteases and carboxypeptidases (pepstatin). Ala AP hydrolyzed alanine amino methylcoumarin (Ala-AMC) maximally, followed by phenyl alanine amino methylcoumarin (Phe-AMC), leucyl amino methylcoumarin (Leu-AMC) and ornithine amino methylcoumarin (Orn-AMC). Ala AP from the three strains showed differential activity towards various substrates. The comparison of alanyl aminopeptidase's activity from different sources is discussed. [source] Differences in reproductive timing among sponges sharing habitat and thermal regimeINVERTEBRATE BIOLOGY, Issue 4 2008Ana Riesgo Abstract. The reproductive cycles of four Mediterranean demosponges (Axinella damicornis, Corticium candelabrum, Raspaciona aculeata, and Chondrosia reniformis) were investigated during 2 consecutive years. Three of the species had annual gametogenic cycles characterized by a single peak of gamete production, but members of C. candelabrum showed continuous oocyte production during the 2 years. The relationship between gametogenic dynamics and seawater temperature varied substantially among species, contrary to the widespread belief that gamete production is associated with seasonal water warming. The annual temperature increase (in June) concurred with oocyte production only in C. reniformis, although maximum temperatures were simultaneous with the production of both oocytes in R. aculeata and sperm in C. reniformis. In contrast, the annual temperature decline in October was associated with both oogenesis in A. damicornis and spermatogenesis in R. aculeata. Spermatogenesis in A. damicornis started after a 5-month period of low-temperature values (December,April in 2004 and November,March in 2005). Likewise, in C. candelabrum, spermatogenesis started after a 3-month period of low-temperature values (November,February), a period concomitant with a slow increase in oocyte production. These findings reveal that sponge species that cooccur and share similar thermal regimes may differ substantially in their timing of gamete production. If we are to predict the future effects of climate change on marine benthic communities, there is an urgent need to improve our knowledge of the species-specific relationship between timing of gametogenesis and temperature, at least for those sponges that are key species in benthic communities. [source] Thermally stimulated depolarization study in polyvinylidenefluoride,polysulfone polyblend filmsJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2010Pooja Saxena Abstract Thermally stimulated depolarization currents (TSDCs) in short- and open-circuit modes in polyvinylidenefluoride (PVDF),polysulfone (PSF) polyblend have been recorded. The TSDC thermograms of PVDF and PSF in short-circuit mode show two peaks, whereas the polyblend of the two polymers shows a single peak. With the increase in PSF weight percentage in the polyblend, the magnitude of TSDC peak current increased and the peak current position shifted toward the lower temperature side. The single peak in polyblend appears at 165°C ± 10°C, which is at higher temperature than the temperature of low-temperature peak for individual polymers. This suggests that this peak may be due to dipolar polarization. Subsequently, shifting of peak toward higher temperature side with increase in polarizing temperature indicates the space charge peak. This contradiction has been explained on the basis of induced dipole theory. The behavior of short circuit TSDC could be explained in terms of the heterocharge caused by dipole orientation and ionic homocharge drift, together with the injection of charge carriers from electrodes and their subsequent localization in surface and bulk traps. However, two oppositely directed TSDC peaks observed in open-circuit mode in all the polyblend samples could be considered as the result of superposition of two overlapped and oppositely directed peaks, one caused by relaxation of dipole polarization and the other by the space charge. Thus, we have compared TSDC measured in open- and short-circuit modes to distinguish between these two relaxation processes and separate them. There is only one broad peak observed in the short-circuit mode of the polyblend, which entirely corresponds to the relaxation of dipole polarization. Insertion of a dielectric gap in the open-circuit mode does not affect the dipole current, but the space charge component flowing in the opposite direction is added to the former. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] PURIFICATION AND CHARACTERIZATION OF BACTERIOCIN FROM WEISSELLA PARAMESENTEROIDES DFR-8, AN ISOLATE FROM CUCUMBER (CUCUMIS SATIVUS)JOURNAL OF FOOD BIOCHEMISTRY, Issue 5 2010AJAY PAL ABSTRACT Bacteriocin from Weissella paramesenteroides DFR-8 isolated from cucumber (Cucumis sativus) was purified by using only two steps, viz., pH-mediated cell adsorption,desorption method and gel permeation chromatography. A single peak observed in the purity check by analytical Reverse Phase-High Performance Liquid Chromatography (Waters 600 analytical HPLC system, Milford, MA) and a single band (molecular weight,3.74 kDa) shown on SDS-PAGE analysis strongly indicated the homogeneity of the bacteriocin preparation. Treatment with proteolytic enzymes abolished the antimicrobial activity indicating the proteinaceous nature of bacteriocin. The purified bacteriocin exhibited a broad inhibitory spectrum against foodborne pathogens and spoilage microorganisms, including gram-negative bacteria such as Salmonella typhimurium, Vibrio parahaemolyticus, Aeromonas hydrophila and Listeria monocytogenes. Response surface methodology was employed to study the interactive effect of temperature and pH on bacteriocin activity, and a regression equation was developed. The bacteriocin retained full activity after storage at,20C for 90 days, while partial and complete activity loss was observed when stored at 4 and 37C, respectively. PRACTICAL APPLICATION In recent years, bacteriocins of lactic acid bacteria have gained much attention as food biopreservatives because of their origin from generally regarded as safe organisms. In spite of various bacteriocins studied worldwide, studies on bacteriocins of Weissella paramesenteroides remain rare. The present work involves the purification of bacteriocin up to absolute homogeneity from W. paramesenteroides, an isolate first time reported from cucumber (Cucumis sativus). The purified bacteriocin (molecular weight ,3.74 kDa) was found to inhibit a large number of foodborne pathogens, including Listeria monocytogenes, which is resistant to commercially available bacteriocin, i.e., nisin. The application of central composite rotatable design enabled us to design a regression equation from which the residual activity of bacteriocin can be predicted at any given conditions of temperature and pH within the experimental domain. The broad inhibitory spectrum and thermostability of bacteriocin suggest its potential application in food preservation. [source] Quantification of hepatic steatosis with MRI: The effects of accurate fat spectral modelingJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 6 2009Scott B. Reeder MD Abstract Purpose To develop a chemical-shift,based imaging method for fat quantification that accounts for the complex spectrum of fat, and to compare this method with MR spectroscopy (MRS). Quantitative noninvasive biomarkers of hepatic steatosis are urgently needed for the diagnosis and management of nonalcoholic fatty liver disease (NAFLD). Materials and Methods Hepatic steatosis was measured with "fat-fraction" images in 31 patients using a multiecho chemical-shift,based water-fat separation method at 1.5T. Fat-fraction images were reconstructed using a conventional signal model that considers fat as a single peak at ,210 Hz relative to water ("single peak" reconstruction). Fat-fraction images were also reconstructed from the same source images using two methods that account for the complex spectrum of fat; precalibrated and self-calibrated "multipeak" reconstruction. Single-voxel MRS that was coregistered with imaging was performed for comparison. Results Imaging and MRS demonstrated excellent correlation with single peak reconstruction (r2 = 0.91), precalibrated multipeak reconstruction (r2 = 0.94), and self-calibrated multipeak reconstruction (r2 = 0.91). However, precalibrated multipeak reconstruction demonstrated the best agreement with MRS, with a slope statistically equivalent to 1 (0.96 ± 0.04; P = 0.4), compared to self-calibrated multipeak reconstruction (0.83 ± 0.05, P = 0.001) and single-peak reconstruction (0.67 ± 0.04, P < 0.001). Conclusion Accurate spectral modeling is necessary for accurate quantification of hepatic steatosis with MRI. J. Magn. Reson. Imaging 2009;29:1332,1339. © 2009 Wiley-Liss, Inc. [source] Generalized k -space decomposition with chemical shift correction for non-cartesian water-fat imagingMAGNETIC RESONANCE IN MEDICINE, Issue 5 2008Ethan K. Brodsky Abstract Chemical-shift artifacts associated with non-Cartesian imaging are more complex to model and less clinically acceptable than the bulk fat shift that occurs with conventional spin-warp Cartesian imaging. A novel k -space based iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL) approach is introduced that decomposes multiple species while simultaneously correcting distortion of off-resonant species. The new signal model accounts for the additional phase accumulated by off-resonant spins at each point in the k -space acquisition trajectory. This phase can then be corrected by adjusting the decomposition matrix for each k -space point during the final IDEAL processing step with little increase in reconstruction time. The technique is demonstrated with water-fat decomposition using projection reconstruction (PR)/radial, spiral, and Cartesian spin-warp imaging of phantoms and human subjects, in each case achieving substantial correction of chemical-shift artifacts. Simulations of the point-spread-function (PSF) for off-resonant spins are examined to show the nature of the chemical-shift distortion for each acquisition. Also introduced is an approach to improve the signal model for species which have multiple resonant peaks. Many chemical species, including fat, have multiple resonant peaks, although such species are often approximated as a single peak. The improved multipeak decomposition is demonstrated with water-fat imaging, showing a substantial improvement in water-fat separation. Magn Reson Med 59:1151,1164, 2008. © 2008 Wiley-Liss, Inc. [source] Radiation and postirradiation crosslinking and structure of two unsaturated polyester resinsPOLYMER ENGINEERING & SCIENCE, Issue 9 2008Irina Puci Radiation and postirradiation crosslinking of two unsaturated polyester (UP) resins were monitored, and substantial differences in the reaction course and extents were observed. DSC thermograms of one of the resins showed double peaks and significantly lower residual reaction heats. Extraction revealed that gelation dose of the resin with double peak was twice the gelation dose of the other resin that had single peak in DSC thermograms. Although other components of the polyesters were identical, NMR spectra of the resin with a single peak revealed isophthalic units while in the polyester of the resin having double DSC peaks orthophthalic units were detected. Orthophthalate reduced the compatibility of polyester and styrene and caused the reaction-induced phase separation, influencing gel structure that was visible in scanning electron microscope micrographs. Previously, the double peaks in crosslinking thermograms of UP resins were usually attributed to initiator effects, but here no initiator was used, and, in the literature, we found that the double peaks are almost exclusively present in the thermograms of UP resins containing orthophthalates, whereas in resins with isophthalates double peaks almost never appear. Crosslinking extents were significantly higher in the resin-containing isophthalate and in both cases enhanced by postirradiation reaction that is often neglected. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers [source] Isobaric metabolite interferences and the requirement for close examination of raw data in addition to stringent chromatographic separations in liquid chromatography/tandem mass spectrometric analysis of drugs in biological matrixRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 13 2008Zhengyin Yan In addition to matrix effects, common interferences observed in liquid chromatography/tandem mass spectrometry (LC/MS/MS) analyses can be caused by the response of drug-related metabolites to the multiple reaction monitoring (MRM) channel of a given drug, as a result of in-source reactions or decomposition of either phase I or II metabolites. However, it has been largely ignored that, for some drugs, metabolism can lead to the formation of isobaric or isomeric metabolites that exhibit the same MRM transitions as parent drugs. The present study describes two examples demonstrating that interference caused by isobaric or isomeric metabolites is a practical issue in analyzing biological samples by LC/MS/MS. In the first case, two sequential metabolic reactions, demethylation followed by oxidation of a primary alcohol moiety to a carboxylic acid, produced an isobaric metabolite that exhibits a MRM transition identical to the parent drug. Because the drug compound was rapidly metabolized in rats and completely disappeared in plasma samples, the isobaric metabolite appeared as a single peak in the total ion current (TIC) trace and could easily be quantified as the drug since it was eluted at a retention time very close to that of the drug in a 12-min LC run. In the second example, metabolism via the ring-opening of a substituted isoxazole moiety led to the formation of an isomeric product that showed an almost identical collision-induced dissociation (CID) MS spectrum as the original drug. Because two components were co-eluted, the isomeric product could be mistakenly quantified and reported by data processing software as the parent drug if the TIC trace was not carefully inspected. Nowadays, all LC/MS data are processed by computer software in a highly automated fashion, and some analysts may spend much less time to visually examine raw TIC traces than they used to do. Two examples described in this article remind us that quality data require both adequate chromatographic separations and close examination of raw data in LC/MS/MS analyses of drugs in biological matrix. Copyright © 2008 John Wiley & Sons, Ltd. [source] Circadian Distribution of Paroxysmal Atrial Fibrillation in Patients with and without Structural Heart Disease in Untreated StateANNALS OF NONINVASIVE ELECTROCARDIOLOGY, Issue 3 2009Yoshiaki Deguchi M.D. Background: This study aimed to compare the circadian distribution of the onset, maintenance and termination of paroxysmal atrial fibrillation (PAF) between structural and non-structural heart diseases (SHD and NSHD, respectively) in the untreated state. Subjects and Methods: We included 217 patients with 338 PAF (79 SHD patients with 131 episodes; 138 NSHD patients with 207 episodes). The probabilities for the onset, maintenance and termination of PAF for each hour were analyzed using Holter monitoring data and harmonic models being fitted into a cosinusoidal function. Results: The SHD group had a triphasic circadian pattern at the onset with higher peaks at midnight, in the early morning and in the late afternoon (p < 0.05), whereas the NSHD group showed a single peak at midnight (p < 0.01). The probability of maintenance revealed a single peak during midnight (SHD, p < 0.0001; NHD, p < 0.01). The termination showed a peak at noon in the SHD group (p < 0.05), whereas there was a double peak at 10:00 am and 8:00 pm in the NSHD group (p = 0.06). RR intervals just after the PAF onset showed marked shortening in the daytime initiation PAF as compared to the nighttime initiation PAF in both SHD and NSHD groups (p < 0.01). Conclusion: These observations suggest that the SHD group has very complex onset hours, whereas the NSHD group shows complex termination hours. Reflexly accelerated sympathetic tone just after the PAF onset is suggested in the daytime initiation PAF. [source] Identification of [(GS)2AsSe], in rabbit bile by size-exclusion chromatography and simultaneous multielement-specific detection by inductively coupled plasma atomic emission spectroscopyAPPLIED ORGANOMETALLIC CHEMISTRY, Issue 2 2002Jürgen Gailer Abstract An arsenic,selenium metabolite that exhibited the same arsenic and selenium X-ray absorption near-edge spectra as the synthetic seleno-bis(S -glutathionyl) arsinium ion [(GS)2AsSe], was recently detected in rabbit bile within 25,min after intravenous injection of rabbits with sodium selenite and sodium arsenite. X-ray absorption spectroscopy did not (and cannot) conclusively identify the sulfur-donor in the in vivo sample. After similar treatment of rabbits, we analyzed the collected bile samples by size-exclusion chromatography (SEC) using inductively coupled plasma atomic emission spectroscopy (ICP-AES) to monitor arsenic, selenium and sulfur simultaneously. The bulk of arsenic and selenium eluted in a single peak, the intensity of which was greatly increased upon spiking of the bile samples with synthethic [(GS)2AsSe],. Hence, we identify [(GS)2AsSe], as the major metabolite in bile after exposure of rabbits to selenite and arsenite. The reported SEC,ICP-AES method is the first chromatographic procedure to identify this biochemically important metabolite in biological fluids and is thus a true alternative to X-ray absorption spectroscopy, which is not available to many chemists. Copyright © 2001 John Wiley & Sons, Ltd. [source] The accumulation of ,-Tocopherol and Retinol in the milk of water buffalo is correlated with the plasma levels of triiodothyronineBIOFACTORS, Issue 3-4 2003M. S. Spagnuolo Abstract Milk is the most important source of Retinol and ,-Tocopherol for calves. These antioxidants save the food quality and prevent lipid oxidation in the mammary gland and the calf growing tissues. In Bubalus bubalis, seasonal changes for the plasma levels of both antioxidants were not found. The levels of Retinol and ,-Tocopherol in the milk were 2 and 1.7 times higher in winter than in summer, respectively. These levels were correlated with the plasma level of triiodothyronine, and markedly increased in cows injected with triiodothyronine in summer. The cytosol from alveolar epithelial cells of mammary glands was incubated with ,-Tocopherol and 3H-Retinol and, after gel filtration chromatography, both antioxidants were found associated with proteins migrating as a single peak of 33 kD. The amount of ,-Tocopherol and Retinol binding proteins was 1.5 and 2.3 times higher in winter than in summer respectively. The Retinol binding proteins migrated as two bands (33 and 16 kD) by electrophoresis in denaturing and reducing conditions. Our data suggest that triiodothyronine enhances the transport of both liposoluble antioxidants through the blood-mammary barrier, and demonstrate that proteins of the mammary epithelial cells are involved in such a transport. [source] Cyclopentadienyl technetium (99mTc) tricarbonyl piperidine conjugates: biodistribution and imaging studiesJOURNAL OF LABELLED COMPOUNDS AND RADIOPHARMACEUTICALS, Issue 9 2001Mouldi Saidi Abstract Synthesis of organometallic complexes of 99mTc using the precursor ligands N -methylpiperidino-4[(bispentahaptocyclopentadienyl)iron] carboxylate and N -(isopropyl)-piperidino-4[(bispentahaptocyclopentadienyl)iron]carboxylate is described. The labelling method involved reaction of the ligands with 99mTcO in the presence of Mn(CO)5Br in dimethyl formamide at 150°C for 1 h in an oil bath. The purification of the complexes was carried out by preparative TLC using ethery/n -butyl methyl amine (95:5) solvent system. The purified complexes were characterized by HPLC using acetonitrile:water (80:20) solvent system in a PRP-1 column in which both the complexes were eluted as single peaks. Biodistribution studies carried out in rats showed 2.4±0.14 and 1.1±0.42% of the injected activity in the brain tissue 5 min p.i. for cytectrene I and II, respectively. The brain to blood activity ratio was >15:1 for both the complexes at 5 min p.i. Scintigraphic studies in rabbits showed significant uptake of the activity in the brain with fast clearance from blood. The complexes warrant further investigation as agents for brain imaging. Copyright © 2001 John Wiley & Sons, Ltd. [source] Injector-internal thermal desorption from edible oils performed by programmed temperature vaporizing (PTV) injectionJOURNAL OF SEPARATION SCIENCE, JSS, Issue 15 2006Anja Fankhauser-Noti Abstract Injector-internal thermal desorption is a promising technique for the analysis of a wide range of food components (e. g., flavors) or food contaminants (e. g., solvent residues, pesticides, or migrants from packaging materials) in edible oils and fats or fatty food extracts. Separation from the fatty matrix occurs during injection. Using programmed temperature vaporizing (PTV) injection, the oily sample or sample extract was deposited on a small pack of glass wool from which the components of interest were evaporated and transferred into the column in splitless mode, leaving behind the bulk of the matrix. Towards the end of the analysis, the oil was removed by heating out the injector and backflushing the precolumn. The optimization dealt with the gas supply configuration enabling backflush, the injector temperature program (sample deposition, desorption, and heating out), separation of the sample liquid from the syringe needle and positioning it on a support, deactivation of the support surface, holding the plug of fused silica wool by a steel wire, and the analytical sequence maintaining adsorptivity at the desorption site low. It was performed for a mixture of poly(vinyl chloride) (PVC) plasticizers in oil or fatty food. Using MS in SIM, the detection limit was below 0.1 mg/kg for plasticizers forming single peaks and 1 mg/kg for mixtures like diisodecyl phthalate. For plasticizers, RSDs of the concentrations were below 10%; for the slip agents, oleamide and erucamide, it was 12%. The method of incorporating PTV injection was used for about one year for determining the migration from the gaskets of lids for glass jars into oily foods. [source] Double and triple frequency oscillations observed in resonant tunneling spectroscopy through edge states around an antidotPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 8 2005K. Arai Abstract Resonant tunneling through edge states bounded around an antidot in quantum Hall (QH) regime has been investigated and we have found multiple frequency oscillations in a resonant tunneling through an antidot. We have measured resistance as a function of magnetic field and front gate voltage and found the periodic oscillation in the , = 2 to 1 transition regime. It is related that discrete energy levels are formed in the edge states around the antidot [1]. Not only single peaks but also some split peaks are seen in our data. Fourier power spectrum of the data shows double and triple frequency peak. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Protein labeling by iTRAQ: A new tool for quantitative mass spectrometry in proteome researchPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 3 2007Sebastian Wiese Abstract A novel, MS-based approach for the relative quantification of proteins, relying on the derivatization of primary amino groups in intact proteins using isobaric tag for relative and absolute quantitation (iTRAQ) is presented. Due to the isobaric mass design of the iTRAQ reagents, differentially labeled proteins do not differ in mass; accordingly, their corresponding proteolytic peptides appear as single peaks in MS scans. Because quantitative information is provided by isotope-encoded reporter ions that can only be observed in MS/MS spectra, we analyzed the fragmentation behavior of ESI and MALDI ions of peptides generated from iTRAQ-labeled proteins using a TOF/TOF and/or a QTOF instrument. We observed efficient liberation of reporter ions for singly protonated peptides at low-energy collision conditions. In contrast, increased collision energies were required to liberate the iTRAQ label from lysine side chains of doubly charged peptides and, thus, to observe reporter ions suitable for relative quantification of proteins with high accuracy. We then developed a quantitative strategy that comprises labeling of intact proteins by iTRAQ followed by gel electrophoresis and peptide MS/MS analyses. As proof of principle, mixtures of five different proteins in various concentration ratios were quantified, demonstrating the general applicability of the approach presented here to quantitative MS-based proteomics. [source] Isolation of Differentiated Squamous and Undifferentiated Spindle Carcinoma Cell Lines with Differing Metastatic Potential from a 4-Nitroquinoline N-Oxide-induced Tongue Carcinoma in a F344 RatCANCER SCIENCE, Issue 12 2000Shinichi Takeuchi One differentiated squamous cell carcinoma (SCC) cell line (RSC3-E2) and two undifferentiated tumor cell lines (RSC3-LM and RSC3-E2R) with different metastatic potential were established from a 4-nitroquinoline N-oxide (4NQO)-induced differentiated SCC in F344 rat tongue. The RSC3-E2 subline was isolated from a parental cell line (RSC3-P) by single cell cloning in vitro, whereas the RSC3-LM subline was isolated from a lung metastatic focus after subcutaneous (s.c.) injection of RSC3-P cells. The RSC3-E2R cell line was isolated from a lung metastatic focus following s.c. injection of RSC3-E2 cells after X-irradiation in vitro. The RSC3-E2 cell line is keratinpositive and grows as a keratinizing tumor in nude mice, whereas RSC3-LM and RSC3-E2R cells are keratin-negative, vimentin-positive and form undifferentiated tumors. When s.c. injected into nude mice, the RSC3-E2 cell line proved to be non-metastatic, while the RSC3-LM cell line was metastatic by both hematogenous and lymphogenous routes, and the RSC3-E2R cell line was metastatic only hematogenously. In vitro relative growth rates and in vitro invasion activity of these cell lines were in the order RSC3-LM>RSC3-E2R>RSC3-E2. Chromosome analysis revealed two peaks with modal chromosome numbers of 83 and 78 for RSC3-P cells and single peaks at 83, 78 and 56 for RSC3-LM, RSC3-E2 and RSC3-E2R cell lines, respectively. Common structural abnormalities on chromosome 11 were shared by all cell lines. Mutation analysis of the p53 gene using a yeast functional assay demonstrated RSC3-LM cell line to have a point mutation at codon 269, whereas RSC3-E2 and RSC3-E2R had double mutations at codons 106 and 170 on each allele. These results suggest that the two undifferentiated RSC3-LM and RSC3-E2R tumor cell lines with different metastatic potential were generated from differentiated SCC cells via different genetic pathways as a consequence of tumor progression in vivo and in vitro, respectively. These cell lines should provide a useful model for understanding mechanisms of hematogenous and lymphogenous metastasis, as well as tumor progression of oral SCCs. [source] | |||||||||||||||||||