Inactivation of tumor suppressor genes like p53 and p16 play a key role in tumor progression, with a high incidence of mutations existing for both genes in oral squamous cell carcinomas. Previous studies have demonstrated, (i) a correlation between the prevalence of p53 mutations and tobacco use [Brennan et al. (1995) New Engl.
View Article and Find Full Text PDFCancer Causes Control
November 1997
The importance of both the CYP1A1 exon 7 (ile:val) and GSTM1 (0/0) polymorphisms in oral cancer susceptibility was assessed by examining polymorphic prevalences in 135 patients with oral cancer and 135 noncancer controls frequency-matched by age at diagnosis (+/- 5 years), race, sex, and institute of patient recruitment. The prevalence of the GSTM1 (0/0) genotype was approximately 51% in both cases and controls. The prevalence of the CYP1A1 (ile:val) polymorphism [including both the (ile/val) and (val/val) genotypes] was significantly higher in cases as compared to controls (17.
View Article and Find Full Text PDFDNA covalently bound to an uncharged nylon membrane was used for consecutive amplifications of several different genes by PCR. Successful PCR amplifications were obtained for membrane-bound genomic and plasmid DNA. Membrane-bound genomic DNA templates were re-used at least 15 times for PCR with specific amplification of the desired gene each time.
View Article and Find Full Text PDFGreater than 55% of all lung cancers contain mutations in the p53 tumor suppressor gene, and the frequency of p53 mutations has been directly correlated with the use of tobacco and the smoking of cigarettes. To determine if environmental tobacco smoke (ETS) is associated with changes in p53 expression in human lung cancer in never-smokers, we determined the degree of p53 protein expression in ten lung tumors from never-smokers exposed to ETS. We show that 5 of 8 (62.
View Article and Find Full Text PDFBackground: Inverted papilloma (IP) of the paranasal sinus is a benign neoplastic condition that can be associated with squamous cell carcinoma (SCC). To understand the etiology of the disease better, paranasal sinus tumor specimens were examined for alterations in either p53 protein expression or genomic DNA sequence, and for infection by human papilloma virus (HPV).
Methods: Tumor specimens were categorized as follows: benign, nondysplastic IP; IP with dysplasia; SCC arising within IP; or SCC without IP.
It is well-established that a high incidence of p53 mutations exist in oral cavity squamous cell carcinomas (OCSCCs). To determine whether p53 mutations are etiologically associated with OCSCC development or are associated with exposure to specific carcinogens, we have analyzed the conserved regions of the p53 gene (exons 5-9) in 48 OCSCCs obtained from patients with varied tobacco and alcohol use histories by polymerase chain reaction/single strand conformational polymorphism (PCR/SSCP) and DNA sequencing analysis. Thirty-eight percent (18/48) of the OCSCCs exhibited a mutation in exons 5-9 of the p53 gene.
View Article and Find Full Text PDFCancer Detect Prev
November 1996
Toombak is a type of snuff used extensively in the Northern Sudan by a virtually non-smoking/nondrinking population. This Sudanese snuff contains inordinately high levels of the tobacco-specific nitrosamines (TSNAs) Nl-nitrosonornicotine (NNN) and (4-methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). These are considered to be major contributors to the induction of cancers of the aerodigestive tract in tobacco chewers, snuff dippers, and smokers.
View Article and Find Full Text PDFTo determine the incidence of p53 mutations in pre-malignant lesions of the oral cavity from individuals without prior history of tobacco use, we have analyzed the conserved regions of the p53 gene (exons 5-9) in archival oral cavity lesion specimens obtained from patients with varied tobacco use histories, by polymerase chain reaction/single strand conformational polymorphism (PCR/SSCP) and DNA sequencing analysis. Twenty-six lesions were analyzed from 14 patients, with multiple lesions obtained from 8 patients. Six of these patients used tobacco, (3 being cigarette smokers, 1 ex-cigarette smoker, 1 moderate cigar smoker and 1 snuff chewer).
View Article and Find Full Text PDFThe hypoxanthine guanine phosphoribosyltransferase (HPRT) gene is mutated by a variety of genotoxic agents in adult rat liver (ARL) epithelial cell lines. By polymerase chain reaction (PCR) amplification and DNA sequencing of rat ARL cell HPRT gene sequences with mouse- and rat-specific oligonucleotides, a large portion of the rat HPRT transcriptional promoter region was sequenced. This region exhibits approximately 60% homology with the corresponding mouse sequence, contains a similar G/C-rich region at its 3' end, and contains a similar series of 6-nucleotide (nt) GGGCGG repeats.
View Article and Find Full Text PDFCancer Lett
November 1994
Sequencing analysis of a 275-nt cDNA fragment encoding the DNA-binding region at the carboxyl terminal of the Xenopus c-jun protein product shows that this region exhibits 77-79% nucleotide homology and 93% amino acid homology with the DNA-binding region of mouse and human c-jun, and contains an intact leucine zipper motif and a basic DNA-binding region. Xenopus c-jun mRNA is induced in quiescent Xenopus A6 kidney cells by 12-O-tetradecanoylphorbol-13-acetate, PDGF and cycloheximide. This 'immediate early' response suggests that Xenopus c-jun may be similar in both structure and function to that observed for its mammalian counterpart.
View Article and Find Full Text PDFTamoxifen (TAM) is a triphenylethylene antiestrogen used for the treatment, and in clinical trials for the prevention, of breast cancer in women. In rats, TAM is a strong liver carcinogen which induces the formation of liver DNA adducts. The DNA of 24 hepatocarcinomas (HCCs) collected at necropsy from individual female Sprague-Dawley rats that were given 22.
View Article and Find Full Text PDFThe translational efficiency of chloramphenicol acetyltransferase (CAT) mRNA containing 5' untranslated region (UTR) sequences of Xenopus c-myc I mRNA was examined in the Xenopus oocyte and early embryo. In contrast to their reduced translation in the oocyte, CAT mRNAs containing 5' UTR sequences located between the c-myc I P0 and P2 promoters translate as efficiently as CAT mRNA controls when injected into early embryos. This pattern of differential regulation of c-myc I translation is similar to that observed for mouse c-myc 5' UTR-containing CAT transcripts during Xenopus oogenesis and early embryogenesis [Lazarus, P.
View Article and Find Full Text PDFIn this report we demonstrate the novel finding that aldolase A interacts with DNA sequences in mouse SEWA sarcoma cells. This interaction was initially observed through the identification of a 40 kDa protein which was eluted from a DNA affinity chromatography column consisting of the long terminal repeat (LTR) of the endogenous intracisternal A-type particle (IAP). Microsequencing analysis identified this 40 kDa protein as the glycolytic enzyme, aldolase A.
View Article and Find Full Text PDFZ Arztl Fortbild (Jena)
October 1989
The translational efficiency of chloramphenicol acetyltransferase (CAT) mRNA containing a 5' noncoding sequence derived from exon 1 of the murine c-myc gene (360CAT) has been examined at different stages of Xenopus egg development. In contrast to its reduced translation in the Xenopus oocyte, 360CAT mRNA is translated as efficiently as CAT mRNA when injected into either mature Xenopus eggs or Xenopus embryos. No significant alteration of 360CAT mRNA stability was observed up to 10 h post-fertilization in Xenopus embryos as compared to that of CAT mRNA.
View Article and Find Full Text PDFSodium cyanate is a selective in vivo inhibitor of protein synthesis in a variety of mammalian tumor cells without a corresponding effect on the normal tissues of tumor-bearing animals. The in vivo decrease of protein synthesis observed 4 h post-NaOCN i.p.
View Article and Find Full Text PDFBiochim Biophys Acta
April 1987
The transport of glycine and L-lysine into murine P388 leukemia cells has been examined. Glycine transport appears to be shared by both systems A and ASC in P388 cells. Glycine transport is Na+-dependent and is effectively blocked by alpha-(methylamino)isobutyric acid, threonine and alanine but only a marginal reduction in transport is seen with 100-fold excess cold 2-aminobicyclo[2,2,1]heptane-2-carboxylic acid.
View Article and Find Full Text PDFUnderlying literature and taking into consideration own experiences in the anticholinergic syndrome the following view is taken: Physostigmine salicylate is the remedy of choice for the treatment of the anticholinergic syndrome and altogether causes only slight side effects. While for differential-diagnostic reasons the application is recommended under hospital conditions, the pre-hospital application is to be estimated as problematical. The improvement of the clinical symptoms under the influence of physostigmine salicylate must not lead to the neglect of the control of the patient.
View Article and Find Full Text PDFThe transport of L-threonine and L-glutamine into murine P388 leukemia cells has been characterized. Threonine appears to be a specific substrate for a Na+-dependent amino acid transport system similar to system ASC of the HTC hepatoma cell. Threonine transport is uninhibited by 2-aminobicyclo[2,2,1]heptane-2-carboxylic acid and alpha-(methylamino)isobutyric acid, shows a pattern of transport similar to that seen in HTC hepatoma cells over the pH range of 5.
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