bluuebunny/crossref_metadata_2025 huggingface dataset:
Preferential primary‐response gene expression in promotion‐resistant versus promotion‐sensitive JB6 cells
Authors: Cmarik Joan L. , Herschman Harvey , Colburn Nancy H.
Published: February 2007

The 12‐O‐tetradecanoylphorbol‐13‐acetate (TPA)‐inducible sequence (TIS) genes are a set of primary response genes induced in Swiss 3T3 cells by TPA. They include three transcription factors, a prostaglandin synthase, and three proteins of unknown function. To ascertain which, if any TIS genes might be involved in tumor promotion, we examined the expression of these genes in response to tumor promoters in transformation promotion‐sensitive (P+) and ‐resistant (P‐) JB6 murine epidermal cells, a model used to identify events relevant to promotion. A subset of TIS genes (TIS1,TIS21), TIS10, and TIS21) was preferentially induced by TPA in P‐cells. In addition, TIS1 and TIS21 mRNAs were preferentially induced in P‐cells by epidermal growth factor, another transformation promoter that distinguishes P+ from P‐ cells. TIS1 and TIS21 protein levels were also greater in TPA‐treated P‐ cells than P+ cells. Forskolin, a cAMP‐elevating anti‐promoter, increased TPA‐induced levels of TIS1, TIS10, and TIS21 mRNAs in P+ cells, ruling in potential roles for these genes in modulating tumor promotion. The anti‐promoters fluocinolone acetonide, retinoic acid, and superoxide dismutase did not enhance TPA‐induced levels of TIS1 and TIS21 mRNAs in P+ cells, suggesting that these inhibitors may act on other promotion‐relevant genes. TIS1 encodes a member of the steroid receptor superfamily. TIS21 encodes a protein of unknown function with strong sequence similarity to BTG1, a proposed “anti‐proliferative gene” (Rouault JP, Rimokh R, Tessa C, et al., EMBO J 11:1663–1670, 1992). Preferential induction by multiple promoters of these TIS genes in P‐ cells and enhancement of their induction in P+ cells by the anti‐promoter forskolin make TIS1 and TIS21 candidates for promotion suppressor genes. ©1994 Wiley‐Liss, Inc.
Polyamine‐dependent expression of the matrix metalloproteinase matrilysin in a human colon cancer—derived cell line
Authors: Wallon U. Margaretha , Shassetz L. Richard , Cress Anne E. , Bowden G. Tim , Gerner Eugene W.
Published: February 2007

Matrilysin, which is a member of the matrix metalloproteinase family and is implicated in colon cancer invasion, is expressed in human colon adenocarcinoma—derived SW1116 cells. We investigated the effect of α‐difluoromethylornithine (DFMO) on matrilysin expression in this cell line because others have shown that DFMO can inhibit invasion and carcinogenesis in epithelial tissues, including the colon, in experimental models. DFMO reduced extracellular levels of matrilysin protein after 4 d of treatment. Intracellular levels of matrilysin protein were minimally affected by DFMO treatment. The decrease in extracellular matrilysin protein levels caused by DFMO was not a consequence of lowered steady‐state levels of matrilysin mRNA. After 4 d of exposure, the amount of this transcript was higher in DFMO‐treated cells than in untreated cultures, whereas the mRNA stabilities were similar. These data show that polyamine depletion by DFMO can suppress the expression of matrilysin, a gene product thought to be involved in tumor invasion. The decrease in extracellular matrilysin protein caused by DFMO treatment appears to be due to a posttranscriptional mechanism, although transcription of this gene also seems to be affected by polyamines in SW1116 cells. ©1994 Wiley‐Liss, Inc.
Induction of activating mutations in the human c‐Ha‐ras‐1 proto‐oncogene by oxygen free radicals
Authors: Du Ming‐Qing , Carmichael Paul L. , Phillips David H.
Published: February 2007

The mutagenicity of oxygen free radicals was studied in a forward mutation system. pEC plasmid containing the human c‐Ha‐ras‐1 proto‐oncogene was reacted with oxygen free radicals generated by Cu2+ and H2O2 and was then transfected into NIH/3T3 cells. Transformed foci were observed with oxygen free radical—modified DNA but not with unmodified DNA. The mutations responsible for the Ha‐ras‐1 gene activation in 11 transformed foci were characterized. G→T mutations at the second base of codon 12 were found in two transformed foci, A→T transversions at the second base of codon 61 in five foci, and G→T mutations at the third position of codon 61 in four transformed foci. These observed mutations are identical to those commonly found in human skin carcinomas, suggesting that reactive oxygen species may play an important role in the carcinogenesis of these tumors. Interestingly, a significant proportion of mutations was found at the second and third base of codon 61 (CAG). In a previous study, the same oxygen free radical—generating system was found to cause an intrastrand cross‐link between adjacent purine nucleotides at AG sites in DNA (Carmichael et al., Carcinogenesis 13:1127–1135, 1992). These data demonstrate that oxygen radicals can induce DNA damage that can result in a specific activation of a human proto‐oncogene. ©1994 Wiley‐Liss, Inc.
Differential expression of prostaglandin h synthase isozymes during multistage carcinogenesis in mouse epidermis
Authors: Müller‐Decker Karin , Scholz Kirsten , Marks Friedrich , Fürstenberger Gerhard
Published: February 2007

An anti–tumor‐promoting effect of indomethacin and related nonsteroidal anti‐inflammatory drugs (NSAIDs) as well as the ability of the tumor promoter 12‐O‐tetradecanoylphorbol‐13‐acetate (TPA) to increase the level of prostaglandins in murine keratinocytes and mouse epidermis in vivo has been repeatedly documented. Here, the expression of prostaglandin H synthase (PGHS) isozymes, which are major targets of NSAIDs, was investigated in different stages of tumor development in mouse skin. Mouse epidermis in vivo constitutively expressed PGHS‐1. PGHS‐1 steady‐state levels remained unchanged upon induction of acute or chronic epidermal hyperplasia by TPA and in papillomas and carcinomas generated by the initiation‐promotion procedure, with 7,12‐dimethylbenz[a]anthracene as initiator and TPA as promoter. Thus, the elevated prostaglandin level in the acute hyperplastic epidermis was very likely due to PGHS‐2 induction. Repeated applications of TPA resulted in stationary hyperplasia and downregulation of PGHS‐2 expression and prostaglandin levels, suggesting that the epidermis had adapted to the TPA stimulus. In papillomas and carcinomas, however, constitutive overexpression of PGHS‐2 was found, with a large amount of prostaglandin E2 and prostaglandin F2α. Keratinocyte cell lines corresponding to different stages of tumor development also constitutively over‐expressed PGHS‐2. Considered with inhibitor studies, these data suggest that PGHS‐2 has a critical role in skin carcinogenesis. The anti–tumor‐promoting effect of the PGHS inhibitor indomethacin is specifically reversed by prostaglandin F2α, indicating that this prostaglandin type has a significant role in tumor development. © 1995 Wiley‐Liss Inc.
Hyperpigmentation and melanocytic hyperplasia in transgenic mice expressing the human T24 HA‐ras gene regulated by a mouse tyrosinase promoter
Authors: Powell Marianne Broome , Hyman Paul , Bell O. Dianna , Balmain Allan , Brown Ken , Alberts Dave , Bowden G. Tim
Published: February 2007

The tyrosinase promoter has been used to target expression of the mutated human T24 Ha‐ras oncogene in pigment‐producing cells of transgenic mice. Two independent founder mice carrying the transgene survived and showed the same distinct phenotype of muted coat color, deeply pigmented skin with multiple nevi, and twirling behavior. The offspring of one of these founders were developed into a line that stably expressed the same phenotype. Histopathological analysis of the tissues revealed hyperpigmentation and/or melanocytic hyperplasia in the skin, eyes, inner ear, and meningeal membranes in the brain. Reverse transcriptase‐polymerase chain reaction analysis revealed expression of the transgene in skin, brain, and spleen. We propose that these transgenic mice will be a model for studying the process of multistage melanoma carcinogenesis and a system for evaluating potential chemopreventive agents. © 1995 Wiley‐Liss Inc.
The p53 and mdm‐2 genes in human testicular germ‐cell tumors
Authors: Riou Guy , Barrois Michel , Prost Sandrine , Terrier Marie Josée , Theodore Christine , Levine Arnold J.
Published: February 2007

Mutations in the p53 gene are common in many cancers. They have been documented to occur in about 55% of all cancers of 51 different cell and tissue types. These mutations are accompanied by overexpression of the p53 protein in the nucleus of the cell, and this protein has lost its tumor suppressor function. In this study, 25 testicular germ‐cell (TGC) tumors were tested for p53 mutations and the level of p53 protein expression. While 67% of the tumors overproduced the p53 protein in the nucleus of 10‐60% of their cells, in all cases the DNA sequence of exons 4‐9 of the p53 gene was wild type. In this tumor type, there was apparently no selection pressure for p53 mutations. The mdm‐2 gene resides on chromosome 12 (12q13‐q14), a chromosome often altered in TGC tumors. mdm‐2 gene amplification (2.5‐ to 10‐fold) was detected in three (12%) of these TGC tumors. These three tumors, and eight additional TGC tumors, overexpressed mdm‐2 mRNA. There was a good correlation between overexpression of p53 protein and overexpression of mdm‐2 mRNA (P = 0.01). This may well result from the fact that the level of mdm‐2 mRNA is regulated by the p53 level. These studies demonstrate that TGC tumors fail to be selected for p53 mutations but nonetheless frequently expressed high levels of wild‐type p53 protein in the cell nucleus. Perhpas this produces the excellent response to radiation and chemotherapy of these tumors, which generally have a good prognosis. Wild‐type p53 may mediate apoptosis in these cells in response to the DNA damage. © 1995 Wiley‐Liss Inc.
Regulatory elements in the first intron of the mouse ha‐ras gene
Authors: Telliez Jean‐Baptiste , Plumb Mark , Balmain Allan , Bailleul Bernard
Published: February 2007

The Ha‐ras gene is one of the three oncogenes (Ha‐ras, Ki‐ras, and N‐ras) of the ras superfamily of small G proteins. The p21ras proteins encoded by the ras genes are key proteins involved in the transduction of signals from membrane receptor‐tyrosine kinases to downstream targets. The ras genes seem to play a ubiquitous role in the control of cell proliferation and cell differentiation. At the same time, ras genes may perform specific differentiated functions in certain cell types. Little is known about the regulation of expression of the Ha‐ras gene. The first intron of the Ha‐ras gene has been reported to be highly conserved between human and rodent. We investigated the role that this intron may play in the regulation of expression of Ha‐ras. The promoter region of the Ha‐ras gene exhibits characteristics of a housekeeping gene. Deletion analysis shows the existence of an enhancer‐type element in the 5′ region of the first intron (intron 0). DNase I footprinting experiments reveal five sites that interact with nuclear proteins from fibroblast and epithelial cell lines. Deletion and site‐directed mutagenesis of three of these sites show that two are involved in a positive effect and one in a negative effect on the regulation of expression of the mouse Ha‐ras gene. © 1995 Wiley‐Liss Inc.
c‐jun and multistage carcinogenesis: Association of overexpression of introduced c‐jun with progression toward a neoplastic endpoint in mouse JB6 cells sensitive to tumor promoter‐induced transformation
Authors: Watts Rebecca G. , Ben‐Ari Elia T. , Bernstein Lori R. , Birrer Michael J. , Winterstein Dolores , Wendel Edmund , Colburn Nancy H.
Published: February 2007

Tumor promoters such as 12‐O‐tetradecanoylphorbol‐13‐acetate (TPA) and epidermal growth factor (EGF) induce neoplastic transformation, elevated c‐jun protein expression, and activator protein‐1 (AP‐1)‐dependent gene expression in JB6 mouse epidermal cells sensitive to tumor promoters (clone 415a P+ cells). In contrast, JB6 cells resistant to tumor promoter‐induced transformation (clone 307b P‐ cells) exhibit a greatly reduced TPA or EGF inducible c‐jun expression and AP‐1 activity. We have recently shown that induced AP‐1 is necessary for tumor promoter‐induced transformation of P+ cells because introduction of a dominant negative c‐jun mutant into P+ cells inhibits both AP‐1 dependent transactivation and the transformation response to tumor promoter. The intent of the investigation presented here was to test the hypothesis that elevation of AP‐1 activity is sufficient to cause progression to the P+ phenotype in P‐cells or to the transformed phenotype in P+ cells. Clonally derived P+ and P‐ recipient cells transfected with a human c‐jun expression construct and overexpressing c‐jun protein were tested for progression by assaying for constitutive or inducible anchorage independent phenotype and nude‐mouse tumorigenicity. Overexpression of c‐jun did not produce progression in P‐ cells but did increase the probability of progression in P+ cells (two of five transfectant cell lines progressed to the tumor phenotype). In addition, c‐jun overexpression did not increase AP‐1 activity in any of the P‐/c‐jun transfectants or in the two of five P+/c‐jun transfectants that acquired the transformed phenotype. The P+/c‐jun transfectants that showed elevated AP‐1 activity did not progress to the tumor phenotype, demonstrating that an increase in AP‐1 activity is insufficient for this progression. Since P+‐to‐tumor phenotype progression occurred in cells overexpressing c‐jun but not AP‐1, we propose that P+‐to‐transformed phenotype progression is c‐jun dependent and AP‐1 independent. © 1995 Wiley‐Liss, Inc.
Transcriptional repression of smooth‐muscle α‐actin gene associated with human papillomavirus type 16 E7 expression
Authors: Nishida Makoto , Miyamoto Shingo , Kato Hidenori , Miwa Takeshi , Imamura Toshiro , Miwa Katsuhiro , Yasumoto Shigeru , Barrett J. Carl , Wake Norio
Published: February 2007

To explore the role of the E7 viral oncogene from human papillomavirus type 16 (HPV16) in the regulation of cytoskeletal organization, we investigated alterations in particular cytoskeletal components in rat embryonal fibroblasts and three transformants of rat embryonal fibroblast cells produced by transfertions with HPV16 E7 alone (TF1), HPV16 E7 plus adenovirus type 5 E1B (TF3), and HPV16 E7 plus activated Ha‐ras (TF4). Marked reductions in smooth‐muscle (SM) a‐actin content and disrupted organization of stress fibers detected by anti—SM α‐actin antibody were evident in all the transformants. These cytoskeletal manifestations were associated with a significant reduction in the mRNAs in these cells. Transcriptional repression by the E7 gene was observed after transient transfection of a chloramphenicol acetyltransferase reporter gene with SM α‐actin gene promoter. Nucleotides —123 to —39 of the SM α‐actin gene promoter were required for the HPV16 E7 transcriptional repression as shown by the chloramphenicol acetyltransferase assay. The downregulation of this actin isoform mediated by the E7 oncoprotein may play an important role in cell transformation by HPV16. © 1995 Wiley‐Liss, Inc.
p53 mutations in matched primary and metastatic human tumors
Authors: Peller Shoshana , Halevy Ariel , Slutzki Sam , Kopilova Yulia , Rotter Varda
Published: February 2007

Mutations in thep53 tumor suppressor gene have been found to be the most frequent genetic alterations in human malignancies. To further examine the idea that neoplastic progression is associated with mutations in the p53 gene, we analyzed matched primary and metastatic tumor samples. The samples included 15 pairs of breast cancer and metastases to lymph nodes, four pairs of gastrointestinal adenocarcinomas and metastases to liver, one colon adenocarcinoma and metastasis to a lymph node, and one lung carcinoma and metastasis in the pleura. Genomic DNA or cDNA from each tumor sample was amplified by the polymerase chain reaction and labeled by using one biotinylated primer. The DNA strands were separated with magnetic streptavidin beads and sequenced directly. p53 mutations were detected in 11 of 21 patients (52%) in either primary tumors, metastases, or both. In six of these patients the primary tumor and matched metastasis shared the same single mutation. In the other patients an additional mutation in the primary tumor only or a mutation in the metastasis only was observed. Our data suggest that tumor development and progression toward metastasis involves structural alterations in the ps3 gene that occur early in carcinogenesis. In some cases, genetic changes in metastatic spreading may also include the appearance of a mutation in a metastasis derived from a primary tumor expressing wild‐type p53, a selection of metastatic cells with a single mutation from a primary tumor expressing two different mutations, or loss of heterozygosity. © 1995 Wiley‐Liss, Inc.
How are potent bulky carcinogens able to induce such a diverse array of mutations?
Authors: Loechler Edward L.
Published: February 2007

Mutations induced by activated benzo[a]pyrene ((+)‐anti‐B[a]PDE) in Escherichia coli are being investigated, by using both random and adduct‐site–specific mutagenesis approaches. A working hypothesis was proposed that the major adduct of (+)‐anti‐B[a]PDE (formed at N2‐Gua) is able to induce different base‐substitution mutations (e.g., GC→TA vs. GC→AT) depending upon its conformation in DNA, which can be influenced by various factors, notably DNA sequence context. Frameshift mutations are also common with (+)‐anti‐B[a]PDE, and other work suggested that the frameshift and base‐substitution mutagenesis pathways are coupled. The simplest hypothesis to rationalize this interrelationship is that a single (+)‐anti‐BEa[a]PDE adduct in a single conformation can be bypassed via either a frameshift or a base‐substitution pathway. This counterintuitive notion can be reconciled if there are two different kinds of conformations on the pathway to mutagenesis: a class I conformation, which is the initial conformation of a DNA adduct in double‐stranded DNA before its encounter with a DNA polymerase, and a class II conformation, which is the conformation that forms at a single‐strand/double‐strand DNA junction during replication by a DNA polymerase. Thus, GC→TA and GC→AT mutations may be induced by different class I conformations, whereas base substitution and frameshift mutations may be induced by the same class I conformation but by different class II conformations. The pathway of mutagenesis would be dictated by the relevant class I and II conformations, which in turn would be controlled by various factors, notably DNA sequence context. © 1995 Wiley‐Liss, Inc.
Investigation of the cooperative effects of transforming growth factor α and c‐myc overexpression in rat liver epithelial cells
Authors: Presnell Sharon Collins , Thompson Melissa T. , Strom Stephen C.
Published: February 2007

Overexpression of both transforming growth factor (TGF)‐α and c‐myc is consistently reported in hepatic tumors. We transfected rat liver epithelial cells (RLECs) with expression vectors for TGF‐α, c‐myc, or both and analyzed the morphology, biological properties, and tumorigenicity of clones that overexpressed these genes. The transfectants were morphologically indistinguishable from the parental RLECs, but the overexpression of TGF‐α resulted in changes in growth properties and an enhanced response to the mitogenic effects of hepatocyte growth factor. The concomitant overexpression of c‐myc decreased growth factor requirements of the TGF‐α/c‐myc clones compared with RLEC and TGF‐α clones. The TGF‐α and TGF‐α/c‐myc clones were tumorigenic in nude mice at frequencies of 27% and 53%, respectively, indicating that the genes cooperate in malignant transformation. However, the untransformed nature and low tumorigenicity of the transfectants suggest that transformation depends on other cellular events in addition to the overexpression of TGF‐α or c‐myc. Characterization of tumor cell lines showed that in contrast to the transfectants, the tumor clones were morphologically transformed, capable of autonomous growth and anchorage‐independent growth, and aggressively tumorigenic with a frequency of 100%. Clearly, the tumor cells differed from the transfectants and had undergone biological or genetic alterations (or both) as a consequence of the overexpression of TGF‐α or c‐myc. Our data suggest that the overexpression of TGF‐α leads to enhanced responsiveness to hepatocyte growth factor, whereas the concomitant overexpression of c‐myc confers growth‐factor independence, providing a potential explanation of the mechanisms by which the overexpression of these genes results in transformation. © 1995 Wiley‐Liss, Inc.
Allelic loss at the tuberous sclerosis 2 locus in spontaneous tumors in the Eker rat
Authors: Yeung Raymond S. , Xiao Guang‐Hui , Everitt Jeffery I. , Jin Fang , Walker Cheryl L
Published: February 2007

Somatic events leading to the inactivation of tumor suppressor genes often involve chromosomal alterations that can be detected as loss of heterozygosity(a). In the Eker rat, spontaneous tumors of the kidney, uterus, and spleen develop as a result of a germline mutation of the tuberous sclerosis 2(Tsc2) gene. We examined the pattern and frequency of LOH at the predisposing locus in 77 primary tumors and cell lines to gain an understanding of the role of Tsc2 allelic loss in the pathogenesis of Eker‐derived tumors. Although most renal and uterine tumors(primary and cell lines) displayed LOH, splenic hemangiosarcomas did not. Although the presence of normal tissue may account for some of this difference, the possibility exists that an alternative mechanism, such as subtle mutation or gene dosage effects, may be involved during splenic tumorigenesis. Northern analysis confirmed that LOH resulted in loss of the wild‐type transcripts for the Tsc2 gene. Thus, the inactivation of both alleles plays an important role in renal and uterine tumor development, in keeping with Knudson's two‐hit hypothesis. In addition, renal tumors that retained the wild‐type allele also did not express the normal transcript, suggesting that the remaining Tsc2alleles had acquired subtle mutations resulting in loss of gene function.© 1995 Wiley‐Liss, Inc
Genetic mapping and expression analysis of the murine DNA ligase I gene
Authors: Gariboldi Manuela , Montecucco Alessandra , Columbano Amedeo , Ledda‐Columbano Giovanna M. , Savini Elena , Manenti Giacomo , Pierotti Marco A. , Dragani Tommaso A.
Published: February 2007

We mapped the murine DNA ligase I gene (Lig1) in the mouse genome by using a mapping panel from an interspecific cross. Lig1 mapped to a centromeric part of chromosome 7, a region homologous to human chromosome 19q, where the human homologue LIG1 was localized. In addition, Lig1 expression was analyzed during the course of mouse liver‐cell regeneration induced by partial hepatectomy, necrogenic doses of carbon tetrachloride, or the mitogen 1,4–bis[2–(3,5—dichloropyridyloxy)]benzene. The results demonstrate that Lig1 is expressed in the liver during active cell proliferation. ©1995 Wiley‐Liss, Inc.
LAR‐PTPase cDNA transfection suppression of tumor growth of neu oncogene‐transformed human breast carcinoma cells
Authors: Zhai Yifan , Wirth Julia , Kang Sanmao , Welsch Clifford W. , Esselman Walter J.
Published: February 2007

The incidence of amplification of neu oncogene‐encoded protein tyrosine kinase in human breast cancer strongly supports the concept that protein tyrosine phosphorylation and dephosphorylation are key regulatory mechanisms in the proliferation, differentiation, and neoplastic transformation of breast epithelial cells. We examined the potential regulatory role of protein tyrosine phosphatases (a) in the maintenance of cellular tyrosine phosphorylation by the introduction of leukocyte common‐antigen‐related PTPase (LAR‐PTPase) cDNA into a tumorigenic human breast carcinoma cell line that overexpressed p185neu protein tyrosine kinase. The transfected human breast carcinoma cells expressed elevated levels of LAR‐PTPase as assessed by reverse transcription‐polymerase chain reaction and by analysis of LAR‐PTPase protein. The LAR‐PTPase‐transfected human breast carcinoma cells had a significantly (P<0.01) slower proliferation rate in vitro than control‐trans‐fected cells. When LAR‐PTPase‐transfected cells were inoculated into athymic nude mice, a consistent and significant (P<0.05) suppression of tumor growth was observed. These results provide evidence that a specific PTPase, LAR‐PTPase, can play a suppressive regulatory role in the tumor growth of human breast carcinoma cells that overexpress p185neu protein tyrosine kinase. ©1995 Wiley‐Liss, Inc.
Cytochrome P450 2a of nasal epithelium: Regulation and role in carcinogen metabolism
Authors: Béréziat Jean‐Claude , Raffalli Francoise , Schmezer Peter , Frei Eva , Geneste Olivier , Lang Matti A.
Published: February 2007

In this study, we found that rat nasal coumarin‐7–hydroxylase (a) activity was two orders of magnitude higher than rat hepatic COH activity and could be induced by adding coumarin to the rats' drinking water. In western blot analysis, an anti‐cytochrome P450 (a) 2a‐5 (mouse liver COH) antibody recognized a sharp band in the microsomal fraction of rat nasal epithelium but not of the liver; the band comigrated with Cyp2a‐5. The intensity of the band was increased by the coumarin treatment. Similarly, in northern blot analysis, a cDNA probe specific for Cyp2a‐5 recognized an mRNA in the nasal epithelium having the same size as mouse liver Cyp2a‐5 mRNA; however, no hybridizable mRNA was recognized in liver preparations. Unlike the protein level, the level of the mRNA was not increased by coumarin. When northern blot analyses were performed with two oligoprobes specific for rat lung CYP2A3, an mRNA of similar size to Cyp2a‐5 mRNA was recognized. In immunoinhibition analysis, anti‐Cyp2a‐5 antibody inhibited rat nasal COH activity and aflatoxin B1 (AFB1) metabolism completely. It inhibited N‐nitrosodiethylamine (a) and 4‐ (a) ‐1‐(3‐pyridyl)‐1‐butanone (a) metabolism by 80–90%. In contrast, the hepatic metabolism of the four compounds was not affected by the antibody. When coumarin instead of anti‐Cyp2a‐5 antibody was used, a strong but variable inhibition of the nasal metabolism of AFB1, NDEA, and NNK was seen. The results suggest that an enzyme or enzymes similar to mouse liver Cyp2a‐5, one of which may be CYP2A3, is expressed at high levels in rat nasal epithelium but not in the liver and that its expression is increased by coumarin, an odorant and a substrate of Cyp2a‐5. The increase probably occurs by protein stabilization or stimulation of translation. The results also show that the enzyme has a key role in the nasal metabolism of three well‐known carcinogens, AFB1, NDEA, and NNK and may therefore be an important contributing factor in nasal carcinogenesis.©1995 Wiley‐Liss, Inc.
Identification of protein kinase C ζ isozyme in hamster pancreas and pancreatic carcinoma cell lines
Authors: Nair Satish C. , Pour Parvis M. , Lawson Terence , Kolar Carol , Vaughn Rick , Birt Diane F.
Published: February 2007

Cellular differentiation and proliferation are dependent upon phosphorylation by endogenous protein kinase C (a) isozymes in many cell types. Western blotting with a C‐terminally directed rabbit polyclonal anti‐PKC ζ antibody detected a doublet of approximately 81 kDa in normal hamster pancreatic tissue and hamster pancreatic carcinoma (PC‐1) and human pancreatic carcinoma (PANC‐1) cells, Preabsorption of the antibody with the specific peptide blocked the appearance of the 81–kDa band, indicating that the band was specifically recognized by the PKC ζ antibody. In contrast, antibodies for PKC α, β, γ, δ, and ϵ failed to show specific immunoreactivity for normal pancreatic tissue or PANC‐1 or PC‐1 cells. Immunocytochemical analysis identified PKC ζ in the cytoplasm of ductules and large ducts, to a lesser extent in the islets of the hamster pancreas, and in the normal cultured pancreatic duct epithelial cells and pancreatic carcinoma (PANC‐1 and PC‐1) cell lines. Specific reactivity was seen by electron microscopy in the ductal cells of the normal pancreatic tissue. In normal pancreatic ductal tissue and primary pancreatic ductal hyperplasia and carcinoma, the proportional labeling of PKC ζ in nuclei and cytoplasm was similar. Our results demonstrating the presence of PKC ζ isozyme in the normal pancreas, cultured normal pancreatic duct epithelial cells, and pancreatic carcinoma cells or carcinoma tissue suggests a role for this isozyme in the normal physiology of the pancreas and perhaps in pancreatic carcinoma. © 1995 Wiley‐ Liss, Inc.
A unique spectrum of p53 mutations in B‐cell chronic lymphocytic leukemia distinct from that of other lymphoid malignancies
Authors: Newcomb Elizabeth W. , Rouby Soumaya El , Thomas Anju
Published: February 2007

The spectrum and pattern of p53 mutations detected in 42 cases of B‐cell chronic lymphocytic leukemia (B‐CLL) were analyzed, and several interesting features were noted. Codon 209 in the p53 gene may be a new hot‐spot for p53 mutation in B‐CLL disease. Four of the 42 (10%) reported B‐CLL p53 mutations occurred at codon 209 versus none in 214 cases of other lymphoid malignancies screened for p53 mutations (P = 0.0006). Transversion mutations predominated at codon 273 rather than the transition mutations that are known to occur at this CpG site. Four of six (67%) B‐CLL cases had transversions at codon 273 compared with two of 17 (12%) of all other lymphoid tumors examined (P = 0.02). In addition, over 65% of the p53 mutations detected in B‐CLL showed a strand bias for p53 mutations on the untranscribed DNA strand. This feature of DNA strand bias is notable in cancers of the lung, esophagus, and head and neck, which may result from high exposure to carcinogens. This spectrum of p53 mutations in B‐CLL together with the high frequency of transversion mutations and DNA strand bias may implicate environmental carcinogens associated with p53 gene damage in some B‐CLL patients. © 1995 Wiley‐ Liss, Inc.
Mutational specificity of 1‐(2‐chloroethyl)‐3‐cyclohexyl‐1‐nitrosourea in the Escherichia coli lacl gene of O6‐alkylguanine‐DNA alkyltransferase‐proficient and ‐deficient strains
Authors: Jurado Juan , Ferrezuelo Francisco , Pueyo Carmen
Published: February 2007

Forward mutations induced by 1‐(2‐chloroethyl)‐3‐cyclohexyl‐1‐nitrosourea (a) in the lacl gene of Escherichia coli were recovered from bacteria proficient (Ogt+ Ada+) and deficient (Ogt− Ada−) in O6‐alkylguanine‐DNA alkyltransferase activity. A CCNU dose of 1 mM was selected for DNA sequence analysis. A total of 245 induced mutations were characterized. The mutations were almost exclusively (95%) GC→AT transitions, indicating that CCNU‐induced mutations arose in bacteria primarily from misreplication of O6‐chloroethylguanine, in total agreement with results obtained for monofunctional alkylating agents. The distribution of CCNU‐induced GC→AT mutations was significantly altered by the presence of DNA alkyltransferase activity (P = 0.01). In the Ogt+ Ada+ mutational spectrum, guanines flanked on both sides by A:T base‐pairs were on average 2.8 times more likely to mutate than those flanked by G:C base‐pairs on at least one side. This bias disappeared in the Ogt− Ada− genetic background, thereby providing evidence that O6‐chloroethylated guanines adjacent to G:C base‐pairs are better targets for bacterial alkyltransferase than those not adjacent to G:C base‐pairs. We recently reported a similar bias for ethyl methanesulfonate, strengthening the idea that CCNU is acting as a simple ethylating compound. In summary, this paper presents for the first time evidence that DNA repair by O6‐alkylguanine‐DNA alkyltransferases plays a major role in removing lesions responsible for GC→AT transitions induced by CCNU, influencing their ultimate distribution with respect to sequence Context. © 1995 Wiley‐ Liss, Inc.
Use of wild‐type p53 to achieve complete treatment sensitization of tumor cells expressing endogenous mutant p53
Authors: Gjerset Ruth A. , Turla Sally T. , Sobol Robert E. , Scalise Jason J. , Mercola Dan , Collins Heli , Hopkins Penelope J.
Published: February 2007

It is known that transfer of the wild‐type p53 gene into p53‐negative cells from transgenic mice increases their sensitivity to drug and radiation‐induced apoptosis. However, unlike many human tumors, these transgenic cells do not express mutant p53, and it is not known from these earlier studies whether wild‐type p53 dominates the effects of mutant p53 with respect to drug and radiation sensitivity. We addressed this question in glioblastoma, a disease characterized by an unusually high level of intrinsic resistance to therapy and poor prognosis: mean survival time from diagnosis is only about 1 yr. We introduced the gene for wild‐type p53 into human T98G glioblastoma cells, which express endogenous mutant p53 but not wild‐type p53. Stable transfectants that co‐expressed mutant and wild‐type p53 had enhanced sensitivity to cisplatin and gamma radiation, compared with parental cells, control vector‐transduced cells, and transduced cells that had lost expression of wild‐type p53. Transient wild‐type p53 expression after high‐efficiency gene transfer by a p53 adenovirus also sensitized the cells to cisplatin and correlated with the induction of apoptosis. The sensitization effect was also observed in p53 adenovirus‐infected H23 small cell lung carcinoma cells, which express endogenous mutant p53. Therefore, wild‐type p53 gene transfer has dominant effects over mutant p53 in sensitizing tumor cells to therapy, which supports the potential of p53 gene therapy to enhance the efficacy of traditional therapy. © 1995 Wiley‐ Liss, Inc.
High frequency of ki‐ras amplification and p53 gene mutations in adenocarcinomas of the human esophagus
Authors: Galiana Corinne , Lozano Jean‐Claude , Bancel Brigitte , Nakazawa Hisayoshi , Yamasaki Hiroshi
Published: February 2007

Mutated ras genes have been found to be conspicuously absent from primary tumors of the esophagus, although high expression of ras p21 oncoprotein in some esophageal squamous cell carcinomas and mutations of the Ki‐ and Ha‐ras genes in esophageal carcinoma cell lines have been reported. In this study, we found amplification of the Ki‐ras gene in four of 10 esophageal adenocarcinomas (40%). No such amplification was observed among 61 squamous cell carcinomas, one pseudosarcomatous carcinoma, and eight esophageal cell lines, nor in six adenocarcinomas of the stomach. In two samples on which immunohistochemical analysis could be performed, we found overexpression of Ki‐ras proteins when compared with normal samples. This Ki‐ras amplification in esophageal tumors did not correlate with any pathological feature of the tumors, with the survival of the patients, or with the presence of other genetic alterations. These findings provide the first evidence for amplification of the Ki‐ras gene in human esophageal cancer, which is restricted to adenocarcinomas. We also found that six of eight adenocarcinomas had point mutations in the p53 gene; this is a considerably higher prevalence than that reported for esophageal squamous cell carcinomas. These results strongly suggest that esophageal adenocarcinomas differ from squamous cell carcinomas in their molecular genetic characteristics. © 1995 Wiley‐ Liss, Inc.
Induction of karyotype instability in a murine tumor cell line by quercetin, 2‐amino‐1‐methyl‐6 phenylimidazo[4,5‐ b]pyridine, and okadaic acid, as revealed by transmission distortion of the inactive X chromosome
Authors: Kuwabara Katsuhiro , Odani Sumiko , Takahashi Yoshiaki , Arakawa Masaaki , Takagi Nobuo , Nagao Minako , Kominami Ryo
Published: February 2007

Quercetin, 2‐amino‐1‐methyl‐6‐phenylimidazo[4,5‐b]pyridine (a), and okadaic acid are found in various foods and have been shown to have mutagenic or promoter‐like activity. The effects of these three compounds on the transmission of the inactive × chromosome were examined in MST‐C6 murine tumor cells, which were derived from hybrid F1 mice from matings between C57BL/6 and MSM mice. Polymerase chain reaction analysis using polymorphic markers on the × chromosome detected transmission distortion of the inactive × chromosome due to nondisjunction as a copy‐number imbalance in allelic bands. The cells exposed to all three chemicals (but not untreated cells) exhibited such imbalances at high frequencies under exposure conditions similar to those in previous experiments in which tumor progression and recombination were observed. The cells also showed increased frequencies of tumor formation when subcutaneously injected. These results suggest that the three chemicals are capable of inducing transmission distortion of the inactive × chromosome and that such activity may be a causative factor in promoting the tumorigenicity of MST‐C6 cells. © 1995 Wiley‐ Liss, Inc.
Reference urodynamic values for stress incontinent women
Authors: Nager C.W. , Albo M.E. , FitzGerald M.P. , McDermott S. , Wruck L. , Kraus S. , Howden N. , Norton P. , Sirls L. , Varner E. , Zimmern P. ,   for the Urinary Incontinence Treatment Network
Published: February 2007

Objective

To determine reference urodynamic values for preoperative urodynamic studies in women undergoing surgery for pure or predominant stress urinary incontinence (SUI).

Materials and Methods

Six hundred fifty‐five women with pure or predominant SUI were enrolled in a multicenter surgical trial and were randomized to undergo a Burch or autologous fascia sling procedure as part of the Urinary Incontinence Treatment Network (UITN) Stress Incontinence Surgical Treatment Efficacy Trial (SISTEr). Preoperative free uroflowmetry, filling cystometry, and pressure flow studies were performed in all women using a standardized research protocol and standardized urodynamic interpretation guidelines. We define the normal range of urodynamic values in this population as the values that encompass 95% of the results.

Results

In 655 women undergoing filling cystometry in the standing position, baseline vesical and abdominal pressures were between 12 and 60 cm H2O. The upper limit of detrusor pressure increase during bladder filling to maximum cystometric capacity was 16 cm H2O. Ten percent of women who qualified for stress incontinence surgery with a positive cough stress test on physical exam did not demonstrate urodynamic stress incontinence (USI) and less than 10% of subjects in this study demonstrated detrusor overactivity.

Conclusions

Results from a large cohort of women with SUI are now available for quantitative plausibility assessments or as reference values when interpreting urodynamic studies. Neurourol. Urodynam. 26:333–340, 2007. © 2007 Wiley‐Liss, Inc.
Current status of functional MRI on small animals: application to physiology, pathophysiology, and cognition
Authors: Van der Linden Annemie , Van Camp Nadja , Ramos‐Cabrer Pedro , Hoehn Mathias
Published: February 2007

This review aims to make the reader aware of the potential of functional MRI (fMRI) in brain activation studies in small animal models. As small animals generally require anaesthesia for immobilization during MRI protocols, this is believed to be a serious limitation to the type of question that can be addressed with fMRI. We intend to introduce a fresh view with an in‐depth overview of the surprising number of fMRI applications in a wide range of important research domains in neuroscience. These include the pathophysiology of brain functioning, the basic science of activity, and functional connectivity of different sensory circuits, including sensory brain mapping, the challenges when studying the hypothalamus as the major control centre in the central nervous system, and the limbic system as neural substrate for emotions and reward. Finally the contribution of small animal fMRI research to cognitive neuroscience is outlined. This review avoids focusing exclusively on traditional small laboratory animals such as rodents, but rather aims to broaden the scope by introducing alternative lissencephalic animal models such as songbirds and fish, as these are not yet well recognized as neuroimaging study subjects. These models are well established in many other neuroscience disciplines, and this review will show that their investigation with in vivo imaging tools will open new doors to cognitive neuroscience and the study of the autonomous nervous system in experimental animals. Copyright © 2007 John Wiley & Sons, Ltd.
Scapular development from the neonatal period to skeletal maturity: A preliminary study
Authors: Rissech C. , Black S.
Published: February 2007

An understanding of the basic growth rates and patterns of development for each element of the human skeleton is important for a thorough understanding and interpretation of data in all areas of skeletal research. Yet surprisingly little is known about the detailed ontogenetic development of many bones, including the scapula. With the intention of describing the changes that accompany postnatal ontogeny in the scapula and algorithms to predict sub‐adult age at death, this communication examines the development of the scapula through nine measurements (3 from the glenoidal area, 4 from the body and 2 related to the spinous process) by polynomial regression. Data were collected from 31 of the individuals that comprise the Scheuer Collection, which is housed at the University of Dundee (Scotland).

Four of the derived mathematical curves (scapular length, infra‐ and suprascapular height and spine length) displayed linear growth, whilst three (maximum length of the glenoid mass, acromial width and scapular width) were best expressed by a second‐degree polynomial and two (maximum and middle diameter of the glenoidal surface) by a third‐degree polynomial. All single measurements proved useful in the prediction of age at death, although derived indices proved to be of limited value. In particular, scapular width, suprascapular height and acromial width showed reliable levels of age prediction until late adolescent years. Copyright © 2007 John Wiley & Sons, Ltd.
Sexing cattle horn‐cores: problems and progress
Authors: Sykes N. , Symmons R.
Published: February 2007

It has long been recognised that cattle horn‐cores are sexually dimorphic, and many methods have been developed using archaeological material for differentiating between specimens belonging to cows, bulls and oxen. Whilst these techniques have been adopted widely by zooarchaeologists, in particular those studying medieval and post‐medieval tannery and horn‐working assemblages, they are highly subjective and their reliability has never been tested using material from cattle of known sex. This paper seeks to redress the balance. It presents the results of a study of 19th and 20th century cattle horn‐cores, from animals of known age, sex and breed, which were examined and measured in order to test the validity of traditional horn‐core sexing techniques. Previously claimed traits of sexual variation are here refuted, and a new metrical threshold for separating the males and females of ‘medium‐horned’ and ‘long‐horned’ types are presented. Copyright © 2007 John Wiley & Sons, Ltd.
Medieval whiplash? A case study
Authors: Holck P.
Published: February 2007

Many people believe that so‐called whiplash injury or disease is something new, a highly disputed mixture of muscular pain and nervous symptoms in the head, neck and upper limbs caused by vehicular accidents. However, the term ‘whiplash’ is only a description of the mechanism—the quick extensive movement of the head caused by the acceleration of the body—for example, by a rear‐end car crash. Of course, there are many possible ways to achieve the same injury in the ligaments of the neck: for example, by falling from a horse or being knocked out in a fight. A male skeleton from the Middle Ages displays typical changes which lead us to believe that the person may have suffered from severe neck trauma years before his death. Copyright © 2007 John Wiley & Sons, Ltd.
Molekularpharmakologie und medizinische Chemie der Fibrate. Wirkstoffe zur Senkung des Triglyceridspiegels
Authors: Steinhilber D. , Schubert‐Zsilavecz Manfred
Published: February 2007

Kardiovaskuläre Erkrankungen stellen weltweit die häufigste Todesursache dar. Störungen des Lipidstoffwechsels wie Hypertriglyceridämien und Hypercholesterolämien sind Risikofaktoren für die Ausbildung dieser Erkrankungen. Während hohe Triglyceridspiegel als alleiniger Marker für das Atheroskleroserisiko umstritten sind, scheint der Parameter bei der Assoziation mit niedrigen HDL‐Cholesterolspiegeln, Adipositas, Diabetes usw. ein signifikanter Marker darzustellen. Fibrate sind Fettsäuremimetika, welche den Triglyceridspiegel durch Aktivierung des nuklären Rezeptors PPARα senken. Die PPARα‐Aktivierung erhöht im Organismus den Abbau Triglycerid‐reicher Partikel, steigert die Hydrolyse von Triglyceriden, den Fettsäureabbau und senkt die Triglyceridsynthese. Diese Effekte kommen durch die PPARα‐vermittelte Modulation der Expression zahlreicher Gene des Lipidstoffwechsels zustande.
Fibrate bei Lipidstoffwechselstörungen: Klinischer Stellenwert
Authors: Kostner Karam M. , Kostner Gerhard M.
Published: February 2007

Fibrate sind seit über 35 Jahren im klinischen Einsatz. Ihre Wirkung auf molekularer und zellulärer Ebene ergibt sich aus der Aktivierung von PPAR‐α, einem nukleären Rezeptor mit ausgeprägter Wirkung auf Gene des Lipid‐Stoffwechsels. Die drei am häufigsten im klinischen Einsatz befindlichen Fibrate Bezafibrat, Fenofibrat und Gemfibrocil unterscheiden sich in ihrem Wirkungsspektrum und sollten daher differenziert eingesetzt werden. Fibrate werden heute vornehmlich bei isolierten Hypertriglyceridämien, erniedrigten HDL‐Werten und als Zusatztherapie zu anderen Lipidsenkern verwendet.
Nikotinsäure bei Fettstoffwechselstörungen: Molekularer Mechanismus und klinischer Stellenwert
Authors: Ahmed Kashan , Offermanns Stefan
Published: February 2007

Pharmakologische Dosen von Nikotinsäure führen zu einer anhaltenden Veränderung des Lipid‐ und Lipoproteinprofils im Plasma. Insbesondere die Fähigkeit von Nikotinsäure, die Konzentration von HDL‐Cholesterin deutlich zu erhöhen, hat in den letzten Jahren zu einem gesteigerten Interesse an dem pharmakologischen Potenzial der Nikotinsäure geführt. Eingeschränkt wird der klinische Einsatz von Nikotinsäure durch meist harmlose, aber unangenehme unerwünschte Wirkungen, insbesondere durch das nach oraler Nikotinsäuregabe auftretende Flush‐Phänomen. Mit der Entdeckung des Nikotinsäure‐Rezeptors ist es gelungen, die Mechanismen der metabolischen und vaskulären Effekte der Nikotinsäure besser zu verstehen. Gegenwärtig werden verschiedene Strategien entwickelt und validiert, mit deren Hilfe das pharmakologische Potenzial von Nikotinsäure besser ausgeschöpft werden kann. Durch neuartige Komedikationen sowie durch die Entwicklung neuer Wirkstoffe, die als Agonisten am Nikotinsäurerezeptor wirken, werden in Zukunft möglicherweise neue Therapieoptionen auf der Basis der pharmakologischen Nikotinsäurewirkungen zur Verfügung stehen.
Der Einsatz von Fischöl bei Fettstoffwechselstörungen. Lipidsenkung ohne Medikamente
Authors: Wächtershäuser Astrid , Stein Jürgen
Published: February 2007

ω3‐Fettsäuren eignen sich hervorragend in der Therapie von Hypertriglyceridämien. Je nach genetischer Disposition können möglicherweise allein durch die Ernährungsumstellung die Triglyceride in den Normbereich gesenkt und eine medikamentöse Therapie umgangen werden. Daher sollte der diätetische Ansatz immer erste Therapieoption sein. Gegebenenfalls können auch Fischölkapseln zum Einsatz kommen. Bei Hypercholesterinämien können aufgrund widersprüchlicher Daten derzeit noch keine Empfehlung zum Einsatz von Fischöl gegeben werden.
Neue Targets und Wirkstoffe zur Behandlung von Fettstoffwechselstörungen: Arzneistoffe in der Pipeline
Authors: Rau Oliver , Zettl Heiko , Popescu Laura Nicoleta , Steinhilber Dieter , Schubert‐Zsilavecz Manfred
Published: February 2007

Die präventive Wirkung einer LDL‐Cholesterol‐Senkung mit Statinen bei Patienten mit Koronarerkrankung ist durch mehrere große Studien belegt und gilt als evidenzbasiert. Pathophysiologisch ebenso schlüssig erscheint das Konzept einer Steigerung von HDL‐Cholesterol zum Schutz gegen Atherosklerose.