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Yoon-Seong Cho's Jazz Korea: A Cross-cultural Musical Excursion

Description: This thesis examines Yoon-Seong Cho's critically acclaimed recording Jazz Korea, in which Cho unites Korean folk music and American jazz into a single form of expression. By reinterpreting Korean folk music through jazz, Cho stimulated interest in the Korean jazz scene and a renewed interest in Korean traditional folk songs. The goal of the thesis, the first musicological essay about Yoon-Seong Cho, is to understand how Cho's diasporic experiences affected his music by leading to a process of self-discovery that allowed Cho to interpret his own identity. Through musical analysis, the study proposes a cultural interpretation of two of Cho's pieces that have achieved popularity not only among Koreans but also internationally: "Arirang" and Han-O-Baek-Nyun.
Date: May 2008
Creator: Joo, Hwajoon
Partner: UNT Libraries

The Products of the Thermal Decomposition of CH3CHO

Description: We have used a heated 2 cm x 1 mm SiC microtubular (mu tubular) reactor to decompose acetaldehyde: CH3CHO + DELTA --> products. Thermal decomposition is followed at pressures of 75 - 150 Torr and at temperatures up to 1700 K, conditions that correspond to residence times of roughly 50 - 100 mu sec in the mu tubular reactor. The acetaldehyde decomposition products are identified by two independent techniques: VUV photoionization mass spectroscopy (PIMS) and infrared (IR) absorption spectroscopy after isolation in a cryogenic matrix. Besides CH3CHO, we have studied three isotopologues, CH3CDO, CD3CHO, and CD3CDO. We have identified the thermal decomposition products CH3(PIMS), CO (IR, PIMS), H (PIMS), H2 (PIMS), CH2CO (IR, PIMS), CH2=CHOH (IR, PIMS), H2O (IR, PIMS), and HC=CH (IR, PIMS). Plausible evidence has been found to support the idea that there are at least three different thermal decomposition pathways for CH3CHO: Radical decomposition: CH3CHO + DELTA --> CH3 + [HCO] --> CH3 + H + CO Elimination: CH3CHO + DELTA --> H2 + CH2=C=O. Isomerization/elimination: CH3CHO + DELTA --> [CH2=CH-OH] --> HC=CH + H2O. Both PIMS and IR spectroscopy show compelling evidence for the participation of vinylidene, CH2=C:, as an intermediate in the decomposition of vinyl alchohol: CH2=CH-OH + DELTA --> [CH2=C:] + H2O --> HC=CH + H2O.
Date: April 6, 2011
Creator: Vasiliou, AnGayle; Piech, Krzysztof M.; Zhang, Xu; Nimlos, Mark R.; Ahmed, Musahid; Golan, Amir et al.
Partner: UNT Libraries Government Documents Department

Disparate requirements for the Walker A and B ATPase motifs ofhuman RAD51D in homologous recombination

Description: In vertebrates, homologous recombinational repair (HRR) requires RAD51 and five RAD51 paralogs (XRCC2, XRCC3, RAD51B, RAD51C, and RAD51D) that all contain conserved Walker A and B ATPase motifs. In human RAD51D we examined the requirement for these motifs in interactions with XRCC2 and RAD51C, and for survival of cells in response to DNA interstrand crosslinks. Ectopic expression of wild type human RAD51D or mutants having a non-functional A or B motif was used to test for complementation of a rad51d knockout hamster CHO cell line. Although A-motif mutants complement very efficiently, B-motif mutants do not. Consistent with these results, experiments using the yeast two- and three-hybrid systems show that the interactions between RAD51D and its XRCC2 and RAD51C partners also require a functional RAD51D B motif, but not motif A. Similarly, hamster Xrcc2 is unable to bind to the non-complementing human RAD51D B-motif mutants in co-immunoprecipitation assays. We conclude that a functional Walker B motif, but not A motif, is necessary for RAD51D's interactions with other paralogs and for efficient HRR. We present a model in which ATPase sites are formed in a bipartite manner between RAD51D and other RAD51 paralogs.
Date: April 21, 2006
Creator: Wiese, Claudia; Hinz, John M.; Tebbs, Robert S.; Nham, Peter B.; Urbin, Salustra S.; Collins, David W. et al.
Partner: UNT Libraries Government Documents Department

Characterization of the mammalian DNA polymerase gene(s) and enzyme(s). Annual progress report

Description: Two Genes for DNA polymerase delta were identified from the wild type Chinese hamster ovary cells. These genes were cloned via RT-PCR from mRNA prepared the Chinese hamster ovary cells using primers specific to conserved sequences of the DNA polymerase {delta} gene. The first gene encodes a PCNA dependent DNA polymerase {delta} gene whereas the second gene encodes a PCNA independent DNA polymerase {delta} gene. Methods were developed to clone these genes in expression vector and host systems. The role of the two genes in DNA replication and repair was determined.
Date: January 1, 1995
Creator: Mishra, N.C.
Partner: UNT Libraries Government Documents Department


Description: The cytotoxic clastogenic and mutagenic effects of the arsenic containing vesicant, Lewisite (L) [dichloro(2-chlorovinyl) arsine], have been investigated using Chinese hamster ovary cells. One hour exposures to Lewisite were cytotoxic in uM amounts. The cell survival response yields a D37 of 0.6 uM and an extrapolation number of 2.5. The mutagenic response at the hypoxantnine-guanine phosporibosyl transferase (HGPRT) locus was sporadic and not significantly greater than control values when cells were exposed over a range of 0.125 to2.0 uM. Sister chromatid exchange (SCE) induction, a measure of chromosomal rearrangement, was weakly positive over a range of 0.25 to 1.0 uM but the values were not significantly greater than the control response. Chromosomal aberrations were induced at 0.75 and 1.0 UMin one experiment and 0.5 and 0.75 uM in another experiment. The Induced values were significantly greater than the control values. Lewisite appears to be cytotoxic and clastogenic in our investigations but SCE and mutation at the HGPRT locus are not significantly greater than control values. Lewisita toxicity was in some ways similar to radiomimetic chemicals such as bleomycin.
Date: May 31, 1989
Creator: Jostes,R.F. Jr.; Sasser, LB & Rausch, R.J.
Partner: UNT Libraries Government Documents Department

LET dependence of DNA-protein cross-links

Description: We have preliminary data indicating a fluence-dependent yield of particle-induced protein cross-links (DPC`s) with a dependency on LET and particle residual energy. Our data indicate that the DPC yield for hamster fibroblasts in vitro irradiated at 32 keV/{mu}m is similar to that reported for hamster cells irradiated with cobalt-60 gamma rays. At 100-120 keV/{mu}m there is some evidence for an enhanced DPC yield with increasing particle fluence, but there are differences in the yields that are dependent on particle track structure.
Date: August 1, 1995
Creator: Blakely, E.A.; Chang, P.Y. & Bjornstad, K.A.
Partner: UNT Libraries Government Documents Department

Characterization of the mammalian DNA polymerase gene and protein. Annual progress report

Description: Methods were developed to purify the DNA polymerases of the {alpha}-family from Chinese hamster cells and their mutants selected as resistant to aphidicolin or specific inhibitor of DNA polymerases of the {alpha}-family. The wild type and mutant DNA polymerases were characterized with respect to their biochemical properties. A methodology was also developed to identify the replication intermediates and aphidicolin was found to inhibit a replication intermediate of the 24Kb size indicating the fact that aphidicolin inhibits the elongation process during DNA replication. This is the first demonstration of such role of aphidicolin in the eukaryotic DNA replication.
Date: January 1, 1993
Creator: Mishra, N.C.
Partner: UNT Libraries Government Documents Department

Characterization of the mammalian DNA polymerase gene(s) and enzyme(s). Annual progress report

Description: Consistent with the long term goal of our research to understand the nature of the key enzymes in eukaryotic DNA replication we have characterized the properties of the wild type DNA polymerases of the {alpha}-family and their mutants. We have also provided evidence for the role of aphidicolin in the elongation process of the in vivo DNA replication in eukaryotic cells. We also developed a technology for planned prep from a large numbers of clones for direct screening by size or restriction digestion in order to facilitate our goals to clone the DNA polymerase gene.
Date: January 1, 1994
Creator: Mishra, N.C.
Partner: UNT Libraries Government Documents Department

Genetically modified CHO cells for studying the genotoxicity of heterocyclic amines from cooked foods

Description: We have developed metabolically competent CHO cells to evaluate the genotoxicity associated with heterocyclic amines, such as those that are present in cooked foods. Into repair-deficient UV5 cells we introduced cDNAs for expressing cytochrome P450IA2 and acetyltransferases. We then genetically reverted these transformed lines to obtain matched metabolically competent repair-deficient/proficient lines. For a high mutagenic response, we find a requirement for acetyltransferase with IQ but not with PhIP. This system allows for both quantifying mutagenesis and analyzing the mutational spectra produced by heterocyclic amines.
Date: July 1, 1995
Creator: Thompson, L.H.; Wu, R.W. & Felton, J.S.
Partner: UNT Libraries Government Documents Department

[Portrait of Dr. Gene Cho]

Description: Photograph of Dr. Gene Cho, Professor of Music Theory & Ethnomusicology. Professor Cho has presented lectures, clinics and workshops in theory, conducting and composition in six countries outside the U.S. In addition, he teaches a sequence of courses in music and culture of China and Japan and directs field study programs to Asia.
Date: 19uu
Partner: UNT Libraries Special Collections

Suppression of mutagenesis by Rad51D-mediated homologous recombination

Description: Homologous recombinational repair (HRR) restores chromatid breaks arising during DNA replication and prevents chromosomal rearrangements that can occur from the misrepair of such breaks. In vertebrates, five Rad51 paralogs are identified that contribute in a nonessential but critical manner to HRR efficiency. We constructed and characterized a Rad51D knockout cell line in widely studied CHO cells. The rad51d mutant (51D1) displays sensitivity to a wide spectrum of induced DNA damage, indicating the broad relevance of HRR to genotoxicity. Untreated 51D1 cells exhibit {approx}5-fold elevated chromosomal breaks, a 12-fold increased rate of hprt mutation, and 4- to 10-fold increased rates of gene amplification at the dhfr and CAD loci, respectively. These results explicitly show the quantitative importance of HHR in preventing these types genetic alterations, which are associated with carcinogenesis. Thus, HRR copes in an error-free manner with spontaneous DNA damage encountered during DNA replication, and Rad51D is essential for this fidelity.
Date: November 15, 2005
Creator: Hinz, J M; Tebbs, R S; Wilson, P F; Nham, P B; Salazar, E P; Nagasawa, H et al.
Partner: UNT Libraries Government Documents Department

The inhibition of radiation-induced mutagenesis by the combined effects of selenium and the aminothiol WR-1065

Description: In order to evaluate the anti-mutagenic effects of the potential chemoprotective compounds selenium and S-2-(3-aminopropylamino)ethylphosphorothioic acid (WR-1065), CHO AA8 cells were exposed to both compounds either individually or in combination prior to irradiation. Mutation frequency following exposure to 8 Gy was evaluated by quantitation of the mutations detected at the hprt locus of these cells. Protection against radiation-induced mutation was observed for both 30 nM sodium selenite or 4 mM WR-1065. In addition, the protection against mutation induction provided by the combination of these agents appeared additive. In contrast, sodium selenite did not provide protection against radiation toxicity when provided either alone or in conjunction with WR-1065. In order to evaluate the possible mechanisms of the anti-mutagenic effects observed in these cells, glutathione peroxidase (GPx) activity was evaluated following exposure to the chemopreventative compounds. The addition of sodium selenite to the culture media resulted in a 5-fold increase in GPX activity, which was unaltered by the presence of the WR-1065. Northern analysis of RNA derived from these cells indicated that selenium supplementation resulted in a marginal increase in the mRNA for the cytosolic GPx (GSHPx-1) which was insufficient to account for the stimulation of GPx activity observed in cellular extracts. These results suggest that selenium and WR-1065 offer protection via independent mechanisms and that GPX stimulation remains a possible mechanism of the anti-mutagenic effect of selenium.
Date: August 1, 1997
Creator: Diamond, A.M.; Murray, J.L. & Dale, P.
Partner: UNT Libraries Government Documents Department

Increased inosine 5{prime}-monophosphate dehydrogenase gene expression in replicating cells: A response to growth factors, not to changes in cell cycle parameters

Description: The authors have analyzed levels of inosine 5{prime}-monophosphate dehydrogenase (IMPDH; E.C. type II mRNA levels in a human melanoma cell line, SK-MEL-131, and a Chinese hamster ovary cell line synchronously progressing through the cell cycle following treatment with aphidicolin. Following release from the aphidicolin block at the G{sub 1}-S phase boundary, the type II IMPDH gene was found to be constitutively expressed at a similar level during all stages of the cell cycle. To analyze growth regulation, as opposed to cell cycle regulation, stable SK-MEL-131 transfectants that express a type II IMPDH-promoted heterologous construct were assayed following deprivation of serum growth factors and after restimulation with fresh serum. Serum deprivation resulted in down-regulation of both steady state type II IMPDH mRNA levels and promoter activity, while restimulation with serum resulted in up-regulation of these parameters. These findings support the conclusion that the increase in IMPDH type II gene expression in replicating cells is mainly due to growth factor regulation rather than changes in cell cycle parameters and that this regulation is mediated primarily by a transcriptional mechanism. The increased level of IMPDH expression and activity found in many tumors may therefore also be due to a transcriptionally mediated response to growth factors.
Date: July 1, 1997
Creator: Tsutani, Hiroshi; Collart, F.R.; Glesne, D.A. & Huberman, E.
Partner: UNT Libraries Government Documents Department

DNA and chromosome breaks induced by {sup 123}I-estrogen in CHO cells

Description: The effects of the Auger electron-emitting isotope I-123, covalently bound to estrogen, on DNA single- and double-strand breakage and on chromosome breakage was determined in estrogen positive Chinese hamster ovary (CHO-ER) cells. Exposure to the {sup 123}I-estrogen induced both single- and double-strand breaks with a ratio of single- to double-strand breaks of 2.2. The corresponding ratio with {sup 60}Co gamma rays was 15.6. The dose-response was biphasic suggesting that either receptor sites are saturated at high does, or that there is a nonrandom distribution of breaks induced by the {sup 123}I-estrogen. The {sup 123}I-estrogen treatment induced chromosome aberrations with an efficiency of about 1 aberration for each 1,000 disintegrations per cell. This corresponds to the mean lethal dose of {sup 123}I-estrogen for these cells suggesting that the lethal event induced by the Auger electron emitter bound to estrogen is a chromosome aberration. Most of the chromosome-type aberrations were dicentrics and rings, suggesting that {sup 123}I-estrogen-induced chromosome breaks are rejoined. The F-ratio, the ratio of dicentrics to centric rings, was 5.8 {plus_minus} 1.7, which is similar to that seen with high LET radiations. Their results suggest that I-123 bound to estrogen is an efficient clastogenic agent, that the cytotoxic damage produced by I-123 bound to estrogen is very like high LET-induced damage, and the I-123 in the estrogen-receptor-DNA complex is probably in close proximity to the sugar-phosphate backbone of the DNA.
Date: July 1, 1997
Creator: Schwartz, J.L.; Mustafi, R.; Hughes, A. & DeSombre, E.R.
Partner: UNT Libraries Government Documents Department

Changes in gene expression associated with radiation exposure

Description: Current research from our group has demonstrated differences in gene induction patterns for high- and low-linear energy transfer radiations; some genes are induced selectively following neutron exposure, others selectively following {gamma}-ray exposure, and others induced following exposure to either. These genes are associated with a broad array of different functions including apoptosis, cytoskeletal function, and gene regulation (dd-RT-PCR) technology to identify genes induced following exposure to different qualities of radiation and following exposure to radiation in the presence of radioprotectors.
Date: December 1995
Creator: Woloschak, G. E.; Paunesku, T.; Chang-Liu, C. M. & Grdina, D. J.
Partner: UNT Libraries Government Documents Department

Women Chief Housing Officers at State Universities in the Northwest United States

Description: Hyatt, Jennifer Leigh. Women Chief Housing Officers at State Universities in the Northwest United States. Doctor of Education (Higher Education), December 2016, 89 pp., 1 table, 3 figures, 48 references, titles. This qualitative study explored the experiences of women chief housing officers (CHOs) at state universities within the northwest region of the United States. The study used narrative inquiry methodology with a thematic analysis approach to investigate how seven female CHOs experience and make meaning of their professional career progression and journey toward becoming and remaining a CHO. Five core themes emerged from the study: (a) understanding housing operations, (b) self-efficacy, (c) gender inequities, (d) relationships with staff, and (e) mentorship. The theme of gender identity suggests that gender does influence how these female CHOs make meaning of their professional experience. The overall results suggest that although the perception of many is that the field of student affairs is wide open to women, in some senior-level positions, such as CHO, gender inequity is prevalent. A factor that may contribute to this inequity is the privatization of housing which calls for a greater understanding of business and housing operations, areas dominated by males. An implication from this study is that an increase in the number of women in the CHO position may only occur when university housing personnel expand professional preparation for mid-level housing positions to include more business-related practices. The mid-level position could then be seen as a step toward desired CHO competencies and toward making the position of CHO more inclusive.
Date: December 2016
Creator: Hyatt, Jennifer
Partner: UNT Libraries

Multagenicity of radon and radon daughters. Final technical report, January 1, 1993--December 31, 1996

Description: The objective of this research was to investigate the dose-response relationship with regard to the lethal and mutagenic effects of exposure of cells to radon and its decay products. Dose-rate dependence was studied, as well as the nature of the DNA lesions. The effect of DNA repair on the lethal and mutagenic effects of exposure and on the character of the DNA lesions was investigated by comparing the response of L5178Y strains that differ in their ability to rejoin X radiation-induced DNA double strand breaks. The nature of radon/radon daughter-induced mutational lesions in human lymphoblasts was also investigated.
Date: June 1, 1997
Creator: Evans, H.H.
Partner: UNT Libraries Government Documents Department

Resolution of heterogeneous fluorescence emission signals and decay lifetime measurement on fluorochrome-labeled cells by phase-sensitive FCM

Description: A phase-sensitive flow cytometer has been developed to resolve signals from heterogeneous fluorescence emission spectra and quantify fluorescence decay times on cells labeled with fluorescent dyes. This instrument combines flow cytometry (FCM) and fluorescence spectroscopy measurement principles to provide unique capabilities for making phase-resolved measurements on single cells in flow, while preserving conventional FCM measurement capabilities. Stained cells are analyzed as they pass through an intensity-modulated (sinusoid) laser excitation beam. Fluorescence is measured orthogonally using a s barrier filter to block scattered laser excitation light, and a photomultiplier tube detector output signals, which are shifted in phase from a reference signal and amplitude demodulated, are processed by phase-sensitive detection electronics to resolve signals from heterogeneous emissions and quantify decay lifetimes directly. The output signals are displayed as frequency distribution histograms and bivariate diagrams using a computer-based data acquisition system. Results have demonstrated signal phase shift, amplitude demodulation, and average measurement of fluorescence lifetimes on stained cells; a detection limit threshold of 300 to 500 fluorescein isothiocyanate (FITC); fluorescence measurement precision of 1.3% on alignment fluorospheres and 3.4% on propidium iodide (PI)-stained cells; the resolution of PI and FITC signals from cells stainedin combination with PI and FITC, based on differences in their decay lifetimes; and the ability to measure single decay nines by the two-phase, phase comparator, method.
Date: January 1, 1993
Creator: Steinkamp, J.A. & Crissman, H.A.
Partner: UNT Libraries Government Documents Department

Chromatin structural changes precede replication in initiated replicons during inhibition of DNA elongation

Description: Partial inhibition of replicative DNA synthesis by hydroxyurea or other agents produces changes in the composition and structure of bulk chromatin. We have begun to investigate the structural changes in specific regions of the genome using synchronized cells and cloned genomic probes. Current results indicate changes in chromatin structure occur preferentially in initiated replicons and can precede the replication fork during inhibition of DNA elongation. 4 refs., 2 figs.
Date: January 1, 1988
Creator: D'Anna, J.A.; Grady, D.L. & Tobey, R.A.
Partner: UNT Libraries Government Documents Department

Molecular and cellular mechanisms of cadmium resistance in cultured cells

Description: Heavy metal induction of the synthesis of metallothioneins (MTs) provides an ideal model system for basic mechanistic studies of gene expression. Cell lines varying in their resistance to heavy metals have been isolated through a regime of exposure to serially increasing levels of Cd followed by clonal isolation. These cell lines have been used to examine the role of methylation and amplification in the Cd-resistant (Cd/sup r/) phenotype. It is suggested that regulation of expression of the MT genes in Cd/sup r/ Chinese hamster cells is modulated at both the transcriptional and translational levels. An analysis of the MT2 gene sequence has uncovered a potential alternative splice site in the first intron. Usage of this site would insert 3 or 12 additional amino acids between amino acids 9 and 10. Analysis of the splicing pattern of the MT2 gene transcript in cultured cells has indicated that the second intron is preferentially removed prior to first intron excision. 34 refs., 2 figs., 1 tab.
Date: January 1, 1985
Creator: Grady, D.L.; Moyzis, R.K. & Hildebrand, C.E.
Partner: UNT Libraries Government Documents Department

Field-flow fractionation of chromosomes

Description: The first topic of this project involved the preparation, fractionation by sedimentation/steric Field Flow Fractionation (FFF), and modeling of metaphase chromosomes. After numerous unsuccessful attempts to prepare chromosomes, we have implemented a procedure (in collaboration with Los Alamos National Laboratory) to prepare metaphase chromosomes from Chinese hamster cells. Extensive experimentation was necessary to identify a suitable FFF channel surface to minimize chromosome adsorption and a carrier liquid to stabilize and disperse the chromosomes. Under suitable operating conditions, the Chinese hamster chromosomes were purified from cell debris and partially fractionated. The purified, preenriched chromosomes that can be prepared by sedimentation/steric FFF or produced continuously by continuous SPLITT fractionation provide an enriched feed material for subsequent flow cytometry. In the second project component, flow FFF permitted successful separations of single- from double-stranded circular DNA, double-stranded circular DNAs of various sizes, and linear double-stranded DNA fragments of various lengths. Diffusion coefficients extracted from retention data agreed well with literature data as well as predictions of major polymer theories. The capacity of FFF separations was evaluated to examine potential applications to long DNA chains.
Date: April 1, 1993
Creator: Giddings, J.C.
Partner: UNT Libraries Government Documents Department

Recent progress with the DNA repair mutants of Chinese hamster ovary cells

Description: Repair deficient mutants of Chinese hamster ovary (CHO) cells are being used to identify human genes that correct the repair defects and to study mechanisms of DNA repair and mutagenesis. Five independent tertiary DNA transformants were obtained from the EM9 mutant. In these clones a human DNA sequence was identified that correlated with the resistance of the cells to CldUrd. After Eco RI digestion, Southern transfer, and hybridization of transformant DNAs with the BLUR-8 Alu family sequence, a common fragment of 25 to 30 kb was present. 37 refs., 4 figs., 3 tabs.
Date: April 2, 1986
Creator: Thompson, L.H.; Salazar, E.P.; Brookman, K.W.; Collins, C.C.; Stewart, S.A.; Busch, D.B. et al.
Partner: UNT Libraries Government Documents Department

Somatic cell and molecular genetics approach to DNA repair and mutagenesis

Description: In the CHO cell line, UV-sensitive mutants representing five genetic complementation groups have been identified. Mutants from each of these groups were shown to be defective in performing the incision step of repair after exposure to UV. The large number of complementation groups of xeroderma pigmentosa mutations has raised the question whether these groups all correspond to single gene loci. The same issue applies to the 5 groups of UV-sensitive CHO mutants. One approach toward answering this question is to localize in the human karyotype the genes that complement the defects in the CHO mutants. Thus, by making CHO/human cell hybrids under the appropriate selective conditions, we have begun to map each of the complementing human genes. The mutation in strain UV20 (Group 2) was complemented by human chromosome 19. Preliminary evidence suggests that UV5 may also be complemented by human chromosome 19 while each of the other 3 groups involves a different human chromosome. Somewhat surprisingly, mutant EM9 is also complemented by a gene on chromosome 19.
Date: June 14, 1985
Creator: Thompson, L.H.
Partner: UNT Libraries Government Documents Department

Genotoxicity of complex mixtures: CHO cell mutagenicity assay

Description: A Chinese hamster ovary (CHO) mammalian cell assay was used to evaluate the genotoxicity of complex mixtures (synthetic fuels). The genotoxicity (mutagenic potency) of the mixtures increased as the temperature of their boiling range increased. Most of the genotoxicity in the 750/sup 0/F+ boiling-range materials was associated with the neutral polycyclic aromatic hydrocarbon (PAH) fractions. Chemical analysis data indicate that the PAH fractions of high-boiling coal liquids contain a number of known chemical carcinogens, including five- and six-ring polyaromatics (e.g., benzo(a)pyrene) as well as four- and five-ring alkyl-substituted PAH (e.g., methylchrysene and dimethylbenzanthracenes); concentrations are a function of boiling point (bp). In vitro genotoxicity was also detected in fractions of nitrogen-containing polyaromatic compounds, as well as in those with aliphatics of hydroxy-containing PAH. Mutagenic activity of some fractions was detectable in the CHO assay in the absence of an exogenous metabolic activation system; in some instances, addition of exogenous enzymes and cofactors inhibited expression of the direct-acting mutagenic potential of the fraction. These data indicate that the organic matrix of the chemical fraction determines whether, and to what degree, various mutagens are expressed in the CHO assay. Therefore, the results of biological assays of these mixtures must be correlated with chemical analyses for proper interpretation of these data. 29 references, 16 figures, 4 tables.
Date: February 1, 1985
Creator: Frazier, M.E. & Samuel, J.E.
Partner: UNT Libraries Government Documents Department