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Biomedical subjects

C C Harris

Publications and source records attributed to C C Harris.

At least 253 records · Page 14Linked to original sources
PubMed1988

Effects of palytoxin or ouabain on growth and squamous differentiation of human bronchial epithelial cells in vitro.

The effects of the non-12-O-tetradecanoylphorbol-13-acetate type tumor promoter palytoxin on human bronchial epithelial cells was studied in an in vitro serum-free culture system. Unlike the results of previous studies with another tumor promoter, 12-O-tetradecanoylphorbol-13-acetate, palytoxin did not induce squamous differentiation of normal bronchial epithelial cells and was equally cytotoxic for normal human bronchial epithelial cells, a human lung tumor cell line, and human bronchial epithelial cells immortalized by infection with adenovirus 12-SV40 hybrid virus (BEAS-2B cells). Palytoxin did not induce a change in free cytosolic Ca2+ concentration of BEAS-2B cells. The effect of palytoxin on the c-myc mRNA steady state level in BEAS-2B cells was studied: 1 pM palytoxin increased the steady-state level at 12 and 18 h. Furthermore, the induction was accompanied by an increase in [3H]thymidine uptake. Because palytoxin binds to (Na+ + K+)ATPase, the effects of ouabain were compared to the effects of palytoxin. A ouabain-resistant cell line was as sensitive to the growth inhibitory effect of palytoxin as the parent ouabain-sensitive cell line, suggesting different binding sites to the (Na+ + K+)-ATPase for palytoxin and ouabain. Ouabain also increased the steady-state level of c-myc gene expression, but earlier than palytoxin, and the increase in the level of c-myc mRNA was accompanied by a drop in DNA synthesis. These results suggest that palytoxin does not act by growth stimulation, differential cytotoxicity or terminal differentiation of normal versus neoplastic cells which are proposed mechanisms of tumor promotion.

Acrylamides↗
PubMed1988

Interlaboratory comparison of antisera and immunoassays for benzo[a]pyrene-diol-epoxide-I-modified DNA.

An interlaboratory comparison of immunoassays using antisera elicited against benzo[a]pyrene-diol-epoxide-modified DNA (BPDE-I-DNA) was carried out resulting in standardization of antisera, competitors and assay conditions. The assays used included competitive enzyme-linked immunosorbent assays (ELISA) with color and fluorescence endpoint detection and an ultrasensitive enzyme radioimmunoassay (USERIA) with a radioactive endpoint. Three different antisera were compared, two of which were obtained from different rabbits immunized with the same BPDE-I-DNA and a third from an animal immunized with another BPDE-I-DNA sample. Samples of standardized BPDE-I-DNA with high (36 pmol adduct/microgram DNA; 1.2 adducts/10(2) nucleotides) and low (4.5 fmol/microgram DNA; 1.5 adducts/10(6) nucleotides) modification levels were prepared and used in each laboratory. The antisera were all elicited against DNAs modified to a high extent, and it was therefore not surprising that they detected adducts in a slightly modified DNA sample with lower efficiency than those in highly modified DNA samples. The discrepancy of antibody recognition between the highly and slightly modified samples varied between 1.4- and 11.2-fold depending on the antiserum and assay. To ascertain the quantitative capability of the immunoassays, the modification level of DNA isolated from mouse keratinocytes treated with [3H]benzo[a]pyrene was determined by radioactivity and immunoassay. These results indicated that when a biological sample is assayed against a BPDE-I-DNA standard modified in the same range as the biological samples (4.5 fmol/microgram), quantitative recovery of adducts is achieved by immunoassay. These studies resulted in the realization that interlaboratory differences in immunoassay procedure can have significant consequences for data comparison and that where possible it is preferable for laboratories to use the same antisera and modified DNA standards.

7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide↗
PubMed1988

Stimulation of DNA synthesis in cultured primary human mesothelial cells by specific growth factors.

Monolayer cultures of human mesothelial cells made quiescent by serum deprivation are induced to undergo one round of DNA synthesis by platelet-derived growth factor (PDGF), epidermal growth factor (EGF), or transforming growth factor type beta 1 (TGF-beta 1). This one-time stimulation is independent of other serum components. The kinetics for induction of DNA synthesis observed for PDGF, EGF, and TGF-beta 1 are all similar to one another, with a peak of DNA synthesis occurring 24-36 h after the addition of the growth factors. Repetitive rounds of DNA synthesis and cell division do not ensue after addition of PDGF, EGF, or TGF-beta 1 alone or in combination; however, in media supplemented with chemically denatured serum, each of these factors is capable of sustaining continuous replication of mesothelial cells. Stimulation of growth by PDGF and TGF-beta 1 is unusual for an epithelial cell type, and indicates that mesothelial cells have growth regulatory properties similar to connective tissue cells.

Cells, Cultured↗
PubMed1988

Human bronchial epithelial cells with integrated SV40 virus T antigen genes retain the ability to undergo squamous differentiation.

Human bronchial epithelial cells transformed by either DNA virus infection (SV40 or Adenovirus 12-SV40 hybrid virus) or transfection with the SV40 large T antigen gene were studied for their ability to undergo squamous differentiation when exposed to 12-O-tetradecanoylphorbol-13 acetate (TPA), transforming growth factor-beta 1 (TGF-beta 1), or fetal bovine serum (FBS), agents that induce the squamous differentiation of normal human bronchial epithelial cells. Squamous differentiation occurred in all ten T-antigen-positive cell cultures when they were exposed to either FBS or TGF-beta 1, but none differentiated when exposed to TPA. From one cell line, designated BEAS-2B, two subclones were isolated, one of which was induced to undergo squamous differentiation by FBS, and a second that failed to undergo squamous differentiation and was mitogenically stimulated when exposed to serum. These phenotypically different subclones provide a new in vitro cellular system for delineating the mechanism(s) of human bronchial epithelial cell squamous differentiation in response to FBS or TGF-beta 1.

Antigens, Viral↗
PubMed1988

Comparison of [125I]HIPDm and [125I]iodoantipyrine in quantifying regional cerebral blood flow in rats.

We determined regional cerebral blood flow (rCBF) using [125I]HIPDm [N,N,N'-trimethyl-N'-(2-hydroxy-3-methyl-5-iodobenzyl)-1,3-propanediamin e] and [125I]iodoantipyrine autoradiography under control and pathologic conditions (hypercapnia [acidosis], hypocapnia [alkalosis], and disrupted blood-brain barrier) conditions in 35 rats. In control rats, HIPDm rCBF (indicator fractionation method, n = 5) was lower than the corresponding IAP rCBF (diffusible indicator method, n = 4), most notably in the infratentorial regions and subcortical nuclei. In hypercapnia, rCBF increased by 100% and 37% in the HIPDm (n = 5) and IAP (n = 5) groups, respectively. In hypocapnia, IAP rCBF (n = 4) decreased 34% but HIPDm rCBF (n = 4) did not change. Following disruption of the blood-brain barrier by intracarotid infusion of mannitol in eight rats, both radiotracers (HIPDm n = 4, IAP n = 4) showed decreased rCBF to regions of disruption as defined by trypan blue extravasation. Our work indicates that modeling HIPDm uptake to quantify rCBF using the indicator fractionation method will underestimate blood flow and that HIPDm kinetics are influenced by compartmental pH dynamics that will limit the accuracy of this method in quantifying rCBF in pathologic conditions.

Acidosis, Respiratory↗
PubMed1988

Detection and characterization of human serum antibodies to polycyclic aromatic hydrocarbon diol-epoxide DNA adducts.

The presence of serum antibodies to the diol-epoxide DNA adducts of representative polycyclic aromatic hydrocarbons (PAH), chrysene, benz[a]anthracene and benzo[a]pyrene, was determined by ELISA using serum samples obtained from normal healthy individuals. Antibodies that reacted against PAH adducted-DNA, but not against PAH-adducted protein, were found in the serum of approximately 40% of the test individuals. Specificity analysis of the antibodies demonstrated that serological cross-reactions between the benzo[a]pyrene and the chrysene diol-epoxide adducts were present. Similar cross-reactivity between the benz[a]anthracene and the chrysene adducts was observed. Sera containing antibodies that were apparently specific for each of the three PAH-DNA adducts were also identified. The presence of antibodies to PAH-DNA adducts indicates both past exposure to these carcinogenic PAH and their metabolic activation to the DNA damaging metabolites. These antibodies may prove to be useful in both retrospective and prospective epidemiological studies of various diseases associated with PAH exposure.

Adult↗
PubMed1988

DNA restriction fragment length polymorphism analysis of human bronchogenic carcinoma.

DNA restriction fragment length polymorphism (RFLP) analysis has been successfully applied both to evaluate possible human susceptibility factors as well as to identify genes involved in malignant transformation of human cells. In this report we review previous applications of RFLP analysis to evaluation of human malignancies and discuss our RFLP studies of human bronchogenic carcinoma, which are in progress. Preliminary results of our analysis of the RFLP associated with the cHa ras variable tandem repeat (VTR) indicate that rare alleles of this VTR are more frequent in patients with bronchogenic carcinoma than in controls.

Carcinoma, Bronchogenic↗
PubMed1988

Human bronchial epithelial cells neoplastically transformed by v-Ki-ras: altered response to inducers of terminal squamous differentiation.

Many human bronchial adenocarcinomas have been shown to contain an activated Ki-ras oncogene (Rodenhuis et al., N. Engl. J. Med. 317 929-935, 1987). To test the hypothesis that activated Ki-ras may be causally related to human bronchial carcinogenesis, v-Ki-ras oncogene was transferred into an established human bronchial epithelial cell line, BEAS-2B, by infection with Kirsten murine sarcoma virus (Ki-MSV) or by transfection with a plasmid containing the transforming region of Ki-MSV. These cells formed poorly differentiated adenocarcinomas in athymic nude mice. Cell lines established from these tumors expressed v-Ki-ras p21 protein and were highly tumorigenic. Whereas serum or transforming growth factor beta 1 induced the BEAS-2B cells at clonal density to undergo growth arrest and squamous differentiation, BEAS-2B cells containing activated ras genes were unaffected by transforming growth factor beta 1 and were mitogenically stimulated by serum.

Animals↗
PubMed1988

Synchronous fluorescence spectrophotometry of benzo[a]pyrene diol epoxide-DNA adducts: a tool for detection of in-vitro and in-vivo DNA damage by exposure to benzo[a]pyrene.

We have applied synchronous fluorescence spectrophotometry (SFS) to study benzo[a]pyrene diol epoxide (BPDE)-DNA adducts in biological samples. Adducts are measured as benzo[a]pyrene (BP) tetrols after acid hydrolysis, and give a peak at 374 nm of emission with a 34-nm wavelength difference. In vitro and in animal studies, there is a positive correlation between the amount of adducts and the BP dose. In cell culture studies, the amount of adducts is increased by increasing both the dose of BP and the time of culture with BP. In preliminary human studies, BPDE-DNA has been found by SFS in placental DNA from some but not all smoking mothers and in blood cell DNA from some individuals in occupationally exposed groups.

7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide↗
PubMed1987

Comparison of production of transforming growth factor-beta and platelet-derived growth factor by normal human mesothelial cells and mesothelioma cell lines.

Steady state mRNA levels for transforming growth factor beta, platelet-derived growth factor (PDGF) A-chain, and PDGF B-chain were measured in normal human mesothelial cells, SV40 large T-antigen expressing human mesothelial cells, and human mesothelioma cell lines. The mRNA expression level for transforming growth factor beta was similar in all three types of culture while normal human mesothelial cells secrete more transforming growth factor beta than do mesothelioma cell lines or T-antigen expressing mesothelial cells. In contrast, both PDGF A- and B-chain mRNAs are expressed at higher levels in mesothelioma cell lines than in normal human mesothelial cells. PDGF-like mitogenic activity was readily detectable in medium conditioned by a mesothelioma cell line and was undetectable in conditioned medium from normal cells. These results suggest the hypothesis that PDGF may be an autocrine growth factor in mesothelioma.

Cell Line↗
PubMed1987

Biochemical and morphological effects of cigarette smoke condensate and its fractions on normal human bronchial epithelial cells in vitro.

We investigated the effect of cigarette smoke condensate (CSC), two basic fractions (BIa and BIb) of CSC, the ethanol-extracted weakly acidic fraction (WAe), and the methanol-extracted neutral fraction (Nmeoh) on the clonal growth rate, plasminogen activator (PA) activity, cross-linked envelope (CLE) formation, and ornithine decarboxylase activity, epidermal growth factor (EGF) binding, thiol levels, and DNA single strand breaks in cultured human bronchial cells. Neither CSC nor any of the fractions were mitogenic over the range 0.01-100 micrograms/ml. All were growth inhibitory at higher concentrations. The 40% growth inhibitory concentrations for CSC, BIa, BIb, WAe, and Nmeoh were 10, 10, 10, 3, and 1 micrograms/ml, respectively. Effects on CLE formation, morphology, PA, and ornithine decarboxylase activities, EGF binding, and thiol levels were evaluated using 40% growth inhibitory concentrations. We found that CSC and all fractions caused an increased formation of CLEs, from a baseline of 0.5% in the untreated cells to a maximum increase of 25% induced by Nmeoh. A squamous morphological change was observed within 1 h after exposure to Nmeoh, WAe, and CSC. The BIa and BIb fractions had little effect. Only Nmeoh increased PA significantly, from 2.5 +/- 0.4 to 5.1 +/- 0.3 units/mg cellular protein. CSC and the WAe and Nmeoh (Nmeoh greater than WAe greater than CSC) fractions caused a decrease in EGF binding, in each case reaching a maximum effect after a 10-12-h incubation. This effect on EGF binding was further characterized in the case of Nmeoh. In untreated normal human bronchial epithelial cells, by Scatchard analysis the kd was 2.0 nM and there were 1.2 X 10(5) receptors/cell. In cells incubated in medium containing Nmeoh (3 micrograms/ml) the kd was 3.2 nM and there were 1.1 X 10(5) receptors/cell. Thus, inhibition of EGF binding by Nmeoh was due primarily to a decrease in the affinity. At the 40% growth inhibitory concentrations neither CSC nor any of the fractions significantly affected intracellular thiol levels. While a 3-h incubation in medium containing CSC caused significant DNA single strand breaks only at a concentration of 100 micrograms/ml, Nmeoh caused a marked effect at 5 micrograms/ml. Neither CSC nor any of the fractions had an effect on ornithine decarboxylase activity. Due to the effects of the Nmeoh fraction on growth, morphology, EGF binding, PA activity, and formation of single strand breaks we consider it to be the most likely portion of CSC to contain compounds with actions similar to those of the phorbol ester, indole alkaloid, and polyacetate tumor promoters.

Bronchi↗
PubMed1987

Preneoplastic and neoplastic growth of xenotransplanted lung-derived human cell lines using deepithelialized rat tracheas.

The human lung tumor-derived cell lines A549, Calu-1, Calu-3, HuT292, and SW900 and the transformed human bronchial epithelial cell line TBE-1, that was transfected with the v-Harvey-ras oncogene, were inoculated into deepithelialized Fisher 344 rat tracheas (5 X 10(5) cells/trachea). After the ends of the tracheas were sealed, the tracheas were transplanted into s.c. tissues of nude mice. In a parallel experiment, 1 X 10(6) cells from each of these cell lines were injected s.c. Histological examination of the tracheal transplants 2, 4, 8, 12, and 16 weeks after cell inoculation proved to be of greater usefulness than either clinical or histological observation of the s.c. injection sites. A549, Calu-1, and TBE-1 produced intratracheal neoplastic nodules as early as 2 weeks after cell inoculation. Calu-3, HuT292, and SW900 grew relatively slowly in the tracheas, and simple or stratified epithelia with slight or moderate atypia (preneoplastic lesions) were seen at 2 weeks. After the 4th week, they produced tumor nodules in the tracheal transplants, whereas no tumor cells could be seen at the s.c. injection sites. The human derivation of the cells was confirmed by in situ hybridization using human-specific DNA probes. The intratracheal inoculation and xenotransplantation of human-derived cell lines offers a time-saving alternative to the s.c. inoculation assay for tumorigenicity and is at the same time a potentially valuable approach to studying preneoplastic and neoplastic progression with human cell subpopulations.

Animals↗