bluuebunny/crossref_metadata_2025_split huggingface dataset:
The isolation of specific chicken macrochromosomes by zonal centrifugation and flow sorting
Authors: Stubblefield Elton , Oro James 
Published: June 2010

AbstractThe nine largest macrochromosomes of the chicken, comprising about 80% of the genome, have each been isolated in yields of about 2 × 106 chromosomes and approximately 80% purity, except for chromosome 4, which is only about 55% pure because it is heavily contaminated with sex chromosome Z. The chromosomes were first separated roughly according to size by zonal centrifugation on a sucrose gradient. Aliquots of the gradient fractions were then stained with ethidium bromide and analyzed by a flow cytometer‐sorter. Electrostatic drop deflection was used to sort the desired chromosomes from chosen zonal gradient fractions. Each fraction was reexamined by flow analysis and by fluorescence microscopy. The DNA from these purified chromosomes has been used for gene mapping by molecular probe analysis.
Isolation of mouse X‐chromosome specific DNA from an X‐enriched lambda phage library derived from flow sorted chromosomes
Authors: Disteche C. M. , Kunkel L. M. , Lojewski A. , Orkin S. H. , Eisenhard M. , Sahar E. , Travis B. , Latt S. A. 
Published: June 2010

AbstractA lambda phage library enriched in X(7) chromosomal material has been constructed from flow sorted chromosomes isolated from mice carrying the Cattanach translocation T(X;7)1Ct. The flow sorted fraction that was cloned contained 40% X(7) chromosomes, so that the resulting lambda phage library should be more than 10‐fold enriched for X chromosomal DNA. Approximately 100,000 lambda phage clones were obtained; of these, at least 80% were recombinant. Three quarters of recombinants were positive for mouse repetitive DNA as detected either by phage plaque filter hybridization or by Southern blotting. Recombinant DNA inserts were prepared from some of the remaining nonrepetitive phage fraction.The X‐chromosome specificity of cloned DNA inserts was tested by hybridization to DNA from mouse‐hamster somatic cell hybrids that had retained all or most of the mouse X as the only mouse chromosome and by comparison of the extent of hybridization to DNA from male and female mice. Out of nine cloned unique sequence segments successfully examined thus far, two were presumably derived from the X. Possession of a phage library highly enriched for mouse X DNA should facilitate molecular studies of the control of X chromosome gene expression.
Flow cytometric characterization of the response of Fanconi's anemia cells to mitomycin C treatment
Authors: Kaiser T. N. , Lojewski A. , Dougherty C. , Juergens L. , Sahar E. , Latt S. A. 
Published: June 2010

AbstractDNA flow histogram analysis, using 33342 Hoechst as a stain, has been used to detect the effect of the potentially bifunctional alkylating agent, mitomycin C (MMC) on dermal fibroblasts from patients with Fanconi's anemia (FA), a hereditary human disease characterized by pancytopenia, hypersensitivity to DNA‐crosslinking agents, congenital abnormalities, and a predisposition for neoplasia. At 24 or 48 hr after a 2‐hr exposure to 0.05 or 0.10 μg/ml MMC, 3HdT incorporation was reduced to a greater extent in FA cells than in normal cells. Cells sorted from the last half of S phase showed a slightly greater inhibition of 3HdT incorporation than did those sorted from the first half of S.Fanconi's anemia cells exhibited a marked accumulation in the G2 + M peak of flow histograms following exposure to MMC. Twenty‐four hr after treatment with 0.05 μg/ml MMC, the G2 + M fraction of FA cells (eight lines) increased to more than 0.5 from a control value of approximately 0.2. Both normals (six lines) and heterozygotes (eight lines) showed, on the average, much less of a G2 + M increment than did FA cells, even after exposure to 0.1 μg/ml MMC. Examination of cells sorted from the G2 + M peak revealed that MMC‐treated FA cells were blocked prior to mitosis.To determine whether the response of FA cells was specific for a bifunctional alkylating agent, cells were also treated with ethylmethanesulfonate, a monofunctional agent. Twenty‐four hours after exposure to 0.25 or 0.5 mg/ml ethylmethanesulfonate, FA and normal cells showed similar, small increases in the G2 + M peak. The results suggest the utility of flow cytometry in the diagnostic evaluation of fibroblasts from patients suspected of having Fanconi's anemia.
Comparative uptake of adriamycin and daunorubicin in sensitive and resistant friend leukemia cells measured by flow cytometry
Authors: Tapiero H. , Fourcade A. , Vaigot P. , Farhi J. J. 
Published: June 2010

AbstractBased on the fluorescence properties of adriamycin (ADM) and daunorubicin (DNR), uptake in sensitive and resistant Friend leukemia cells (FLC) was studied with the aid of the fluorescence activated cell sorter (FACS II). A quantitative cell by cell fluorescence intensity analysis showed a differential affinity of FLC to ADM and DNR. The cellular uptake of these two drugs was temperature dependent and was not hindered by sodium azide treatment; incorporation into isolated nuclei was not temperature dependent, nor hindered by sodium azide. Friend leukemia cell variants resistant to adriamycin (ADM‐RFLC) and to daunorubicin (DNR‐RFLC) were developed. The rate of uptake of ADM and DNR across the plasma membrane of these two cell variants was lower than in sensitive cells. Although these cells were crossresistant to both ADM and DNR, the drug‐induced fluorescence intensity was distributed differently in the corresponding resistant cell variants. We suggest therefore that resistance is the consequence of changes induced in the plasma membrane components. These changes may differ according to which drug is used.
Cytometric evidence of cytogenetic and proliferative heterogeneity of human solid tumors
Authors: Nervi Carlo , Badaracco Gianna , Maisto Anna , Mauro Francesco , Tirindelli‐Danesi Donatella , Starace Giuseppe 
Published: June 2010

AbstractFlow cytometry is a widely recognized method of rapidly assessing the ploidy and proliferative status of experimental and solid tumors. In the present work, a variety of human cancers from various sites (lung, head and neck, etc.), of traditional interest in our laboratory, have been analyzed. In agreement with a number of recent reports, a general heterogeneity of human solid tumors can be evidenced. In particular: (a) solid tumors are characterized by a variable degree of aneuploidy; (b) the internal structure of solid tumors is highly heterogeneous especially with respect to the fraction of aneuploid malignant cells and their distribution through the cycle phases; and (c) some solid tumors are also characterized by the presence, to a variable extent, in the tumor of mass of multiple cell clones. Static fluorimetry of Feulgen‐stained (mitotic) single cells offers a way to confirm this kind of observations.
A standardized differential stain for hematology
Authors: Lapen Daniel 
Published: June 2010

AbstractA stain composed of purified Azure B and Eosin Y has been developed for use in conjunction with an automated stainer. This system provides the consistency in chromatic properties required for automated blood‐cell analysis by pattern recognition systems. The stain represents a marked improvement in stability over those presently used with differential analyzers, but it is also an important advance toward a standardized stain for general hematological use. The purity of the component dyes, the stability of the final stain and the dependence of staining intensity on the stain/buffer ratio and dye concentration are discussed.
Discrimination of G1, S, and G2 cells using high‐resolution TV‐scanning and multivariate analysis methods
Authors: Abmayr W. , Giaretti W. , Gais P. , Dörmer P. 
Published: June 2010

AbstractImages of exponentially growing mouse L fibroblasts were used to test whether G1, S, and G2 cells could be discriminated by means of densitometric, geometric, textural and chromatin features. The cells were preincubated with FUdR and labeled with 3H‐TdR. The definition of G1, S, and G2 was based on autoradiography used to define labeled S cells, and DNA content used to define unlabeled 2c (G1) and 4c (G2) cells.The methanol‐fixed Feulgen‐stained nuclei were scanned with a TV Plumbicon camera equipped with an array‐processor system. Thirty‐one nuclear features were calculated and stored together with the precise coordinates of each cell for later relocation and correlation with the autoradiographic data. The features were geometric, densitometric, textural and chromatin parameters of the Feulgen stained images. Feature evaluation and supervised learning were performed. When DNA content was excluded 14 textural and chromatin features were selected. By using these a correct classification of about 80% was achieved. Inclusion of DNA content and its correlates caused degeneration of performance, yielding 75% correct classification. DNA content alone gave 69% correct classification.
Correlated analysis of cellular DNA, membrane antigens and light scatter of human lymphoid cells
Authors: Braylan Raul C. , Benson Neal A. , Nourse Virginia , Kruth Howard S. 
Published: June 2010

AbstractFlow cytometric correlated analysis of membrane antigens, DNA, and light scatter was performed on human lymphoid cells using fluorescein (FITC)‐conjugated antibodies to label B‐ and T‐cell antigens and propidium iodide (PI) to stain DNA after ethanol fixation and RNase treatment. A FACS II flow cytometer was modified to obtain digitized measurements of two color fluorescence and light scatter emissions, simultaneously. Software was written to allow single parameter analysis or correlated analysis of any two of the three parameters acquired. Ethanol fixation preserved FITC surface labeling for at least 15 weeks, but produced marked changes in light scatter. No changes in FITC distributions were observed after RNase treatment and PI staining, and the presence of FITC labeling did not affect DNA distributions. Within heterogeneous cell populations, the DNA distribution of cell subpopulations identified by a membrane antigen was clearly demonstrated.
Caution on the use of lymphocytes as standards in the flow cytometric analysis of cultured cells
Authors: Wolley Robert C. , Herz Fritz , Koss Leopold G. 
Published: June 2010

AbstractFlow cytometry was used to compare the fluorescence intensity of the G0/G1 peak of a diploid (WI‐38), a hypodiploid (C4I) and a heteroploid (KB) human cell line with that of nonstimulated human lymphocytes. With all three cultured cells the fluorescence intensity was substantially higher than that of lymphocytes. These results, obtained with three different DNA‐intercalating fluorochromes, suggest that lymphocytes may not be the standard of choice for flow cytometric studies of the DNA distribution in human cell cultures and that diploid cells such as WI‐38 may be more appropriate for this purpose.
Selection of optical filters for laser flow cytometry using fluorescent conjugates
Authors: Martin C. Leon , Rolland Jennifer M. , Nairn Richard C. , Muller H. Konrad 
Published: June 2010

AbstractHigh performance optical filters improve sensitivity of detection and resolution of fluorescence in flow cytofluorimetry. Optimal optical barrier filters for laser‐illuminated flow cytofluorimeters differ from those for fluorescence microscopes with wide spectrum illumination. Filters for laser excitation must stop intense illumination at particular wavelengths while transmitting fluorescence emission maximally.Using a Becton, Dickinson Fluorescence Activated Cell Sorter (FACS II) (Becton, Dickinson and Co., Sunnyvale, CA) a range of optical filters were compared for transmission characteristics and performance in fluorescence analysis of cells stained with fluorescein‐ or rhodamine‐labeled antibodies and of green and red fluorescent beads. Interference filters were generally superior to dyed glass filters: the Ortho 528 nm band pass (BP) filter (Ortho Instruments, Westwood, MA) (originally a Schott and Genossen product) was excellent for fluorescein analysis using the 488 nm laser line. In the absence of satisfactory interference filters, a Schott and Genossen 550 nm long pass (LP) filter (Schott America, NY) (dyed epoxy between two glass plates) was best for rhodamine analysis using the 514.5 nm line. Intrinsic fluorescence of some dyed glass filters rendered them unsuitable unless used in a prefiltered light path. Simultaneous analysis using two fluorochromes with overlapping excitation and emission spectra, e.g. fluorescein and rhodamine, will be suboptimal even with electronic dual fluorescence compensation; optimal analysis requires dual laser excitation with geometric separation of the light paths. For single laser systems, sensitivity and resolution are improved by using fluorochromes with fullyseparated emission spectra.
A microsample collection device for electrostatically sorted cells or particles and its preparative use for biochemical analysis
Authors: Hinson W. G. , Pipkin J. L. , Hudson J. L. , Anson J. F. , Tyrer H. 
Published: June 2010

AbstractBiochemical analysis of proteins extracted from mammalian cell nuclei which were sorted according to DNA content was greatly simplified using a special collection device to recover sorted nuclei. The device was developed for use with a sorting flow cytometer to provide sufficient numbers of particles to achieve adequate sensitivity and resolution while minimizing sample degradation and loss. The design, evaluation and application of the collection device were described with emphasis on sample preparation.Nuclear populations G0 + G1, S, and G2 + M, were sorted from regenerating rat liver tissue preparations and collected separately in the special chambers. Nuclear proteins were extracted and analyzed by polyacrylamide gel isoelectric focusing or capillary isotachophoresis.
Rapid isolation of cloned isotype switch variants using fluorescence activated cell sorting
Authors: Dangl Jeffery L. , Parks David R. , Oi Vernon T. , Herzenberg Leonard A. 
Published: June 2010

AbstractWe have used highly specific, directly fluorescein‐conjugated heterologous (conventional) and monoclonal antibodies directed against mouse immunoglobulin isotypes in conjunction with the fluorescence activated cell sorter (FACS) to enrich and clone hybridoma cells producing new immunoglobulin heavy chain constant regions. Each variant retains the parental heavy chain variable region and the parental immunoglobulin light chain; thereby each variant binds the same dansyl (DNS) hapten. These isotype switch variants occur at frequencies of approximately 10−5 to 10−6. We were able to isolate the variants by first sorting for an approximate 1000‐fold enrichment of the desired immunoglobulin‐producing cells, growing these cells for five to nine days, followed by a second 1000‐fold enrichment and direct cell cloning into 96 well culture trays. Clones were screened only 3–5 weeks after the original selection for secretion of dansyl‐binding immunoglobulin of the selected isotype. Judicious combination of existing methods permits improved analytical techniques using the cell sorter. These include: first, “red” fluorescence staining of dead cells with ethidium bromide or propidium iodide and using the red fluorescence measurement to exclude dead cells from the green fluorescence selection; and second, the use logarithmic amplification of fluorescence signals, allowing for more succinct selection of fluorescence parameters for sorting.
Cell cycle and 5′‐nucleotide phosphodiesterase activities in rat liver
Authors: Lo K. W. , Tsou K. C. 
Published: June 2010

AbstractThe postnatal developments of liver and serum 5′‐nucleotide phosphodiesterase (5′‐NPD) in Fischer 344 rats were studied. The liver enzyme activities were found to correlate well with the growth of the liver as measured by the wet weight and percentages of liver cells in the G2/M phases of the cell cycle as determined by flow cytofluorometry. Therefore, this enzyme may be intimately related to the growth of the liver.Although the specific activities of the serum enzyme are three orders of magnitude less than that of the liver enzyme, very good correlation was obtained between the total serum and liver enzyme activities. This finding, therefore, suggests that the main origin of the serum enzyme is from liver. Multiple isozymes were detected in both liver and serum 5′‐nucleotide phosphodiesterase after polyacrylamide gel electrophoresis.
Cell cycle analysis in a human cell line (EUE cells)
Authors: Zippel R. , Martegani E. , Vanoni M. , Mazzini G. , Alberghina L. 
Published: June 2010

AbstractA new procedure to determine the durations of cell cycle phases is based on the autoradiography of labeled nuclei and a standard chemical determination of DNA content per cell. It has been used to study the cell cycle timing of a human established cell line, EUE cells, so far poorly characterized in its kinetic aspects. The cycle phase durations obtained with this method are compared with the DNA frequency profiles determined by flow cytometry and found to agree closely. The relevance of the growth conditions of the exponentially growing cultures for a correct estimation of the cycle phase duration is indicated. Cell size distribution has been shown to vary according to growth condition.
Early stimulation, parental behavior, and the temperature of infant mice
Authors: Barnett S. A. , Walker K. Z. 
Published: June 2010

AbstractThe effects of early conditions of rearing on parental attention and on the heat exchanges of infant mice were examined: (1) Inbred migce 6 days old were exposed at 7.5 °C and returned to the nest. Mice which were rewarmed before return recieved more parental attention then cold mice or handled Controls. (2) Outbred mice 6 days old with injured ears were licked more by there mothers then uninjured litter mates. (3) Liking of genitalia alos occured but was unrelated to ear injury. (4) surface temperature of 6‐day old inbred mice declined at after artifical “licking” with a wet brush. (5) Surfarce temperature of inbred mice exposed at 22–28 °C for 2.5 min. declined at age 0–11 days and increased at age 15–20 days. Exposure at 15°C led to a declined in surface temperature at all ages. (6) Wild or laboratory mice 4 or 6 satge old were observe in their nests. Surface temperature decreased after parental licking or loss of contact with the litter and increased on contact with mother. Temperatures also increased rapidly if the mouse was held on the experimentor's hand.in work on the effects of early conditions of rearing, attention should be paid to the minute details of parental attention and the heat exchanges of the toung animals.
Inorganic Analogues of Graphene
Authors: Rao C. N. R. , Nag Angshuman 
Published: June 2010

AbstractThe discovery of graphene has aroused great interest in the properties and phenomena exhibited by two‐dimensional inorganic materials, especially when they comprise only a single, two or a few layers. Graphene‐like MoS2 and WS2 have been prepared by chemical methods, and the materials have been characterized by electron microscopy, atomic force microscopy (AFM) and other methods. Boron nitride analogues of graphene have been obtained by a simple chemical procedure starting with boric acid and urea and have been characterized by various techniques that include surface area measurements. A new layered material with the composition BCN possessing a few layers and a large surface area discovered recently exhibits a large uptake of CO2.
Platinum‐Catalyzed Regioselective Formation of β‐Alkoxy Ketones from Internal Alkynes
Authors: Yang Daxin , Huang Jianfeng , Liu Bo 
Published: June 2010

AbstractA catalytic amount of Zeise's dimer and 15‐crown‐5 were combined to effectively promote the regioselective formation of β‐alkoxy ketones from 2‐(homopropargyloxy)ethanols in dimethoxyethane. The desired products were obtained in 59–98 % yields with up to 17:1 exo/endo regioselectivity. The methodology allows access to β‐hydroxy ketones as an aldol reaction alternative.
Analyses of sulfonamide antibiotics by a successive anion‐ and cation‐selective injection coupled to microemulsion electrokinetic chromatography
Authors: Lin Yun‐Ta , Liu Yu‐Wei , Cheng Yi‐Jie , Huang Hsi‐Ya 
Published: June 2010

AbstractIn this study, an MEEKC was used to detect and analyze nine sulfonamide antibiotics. Owing to an insufficient sensitivity of on‐column UV detection, a field‐amplified sample injection, successive anion‐ and cation‐selective injection, was used for the on‐line concentration of the nine antibiotics. In the successive anion‐ and cation‐selective injection mode, a leading water plug was introduced prior to anion injection, and then an acidic plug followed by a terminal water plug had to be used before subsequent cation injection. The results indicated some sulfonamides (sulfamonomethoxine, sulfamethazine, sulfamerazine and sulfadiazine) were determined as split signals in pairs, and this was likely due to the use of a longer acid plug (360 s) which caused the sulfonamide anions and cations to be stacked in two distinct zones of the leading water and acid plugs. Meanwhile, all the sulfonamides that were introduced either by anion or cation injection were stacked within the leading water plug when a shorter acid plug (210 s) was used. As a result, the nine sulfonamides were determined as single and symmetrical peaks with low LODs (0.9–4.2 μg/L). Furthermore, the MEEKC method was successfully applied for the detection of trace sulfonamide residues in several food and water samples.
DNA cross‐link induced by trans‐4‐hydroxynonenal
Authors: Huang Hai , Kozekov Ivan D. , Kozekova Albena , Wang Hao , Lloyd R. Stephen , Rizzo Carmelo J. , Stone Michael P. 
Published: June 2010

AbstractTrans−4‐Hydroxynonenal (HNE) is a peroxidation product of ω−6 polyunsaturated fatty acids. Michael addition of HNE to deoxyguanosine yields four diastereomeric 1,N2‐dG adducts. The adduct of (6S,8R,11S) stereochemistry forms interstrand N2‐dG:N2‐dG cross‐links in the 5′‐CpG‐3′ sequence. It has been compared with the (6R,8S,11R) adduct, incorporated into 5′‐d(GCTAGCXAGTCC)‐3' · 5'‐d(GGACTCGCTAGC)‐3′, containing the 5′‐CpG‐3′ sequence (X = HNE‐dG). Both adducts rearrange in DNA to N2‐dG aldehydes. These aldehydes exist in equilibrium with diastereomeric cyclic hemiacetals, in which the latter predominate at equilibrium. These cyclic hemiacetals mask the aldehydes, explaining why DNA cross‐linking is slow compared to related 1,N2‐dG adducts formed by acrolein and crotonaldehyde. Both the (6S,8R,11S) and (6R,8S,11R) cyclic hemiacetals are located within the minor groove. However, the (6S,8R,11S) cyclic hemiacetal orients in the 5′‐direction, while the (6R,8S,11R) cyclic hemiacetal orients in the 3′‐direction. The conformations of the diastereomeric N2‐dG aldehydes, which are the reactive species involved in DNA cross‐link formation, have been calculated using molecular mechanics methods. The (6S,8R,11S) aldehyde orients in the 5′‐direction, while the (6R,8S,11R) aldehyde orients in the 3′‐direction. This suggests a kinetic basis to explain, in part, why the (6S,8R,11S) HNE adduct forms interchain cross‐links in the 5′‐CpG‐3′ sequence, whereas (6R,8S,11R) HNE adduct does not. The presence of these cross‐links in vivo is anticipated to interfere with DNA replication and transcription, thereby contributing to the etiology of human disease. Environ. Mol. Mutagen., 2010. © 2010 Wiley‐Liss, Inc.