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  • 1
    Electronic Resource
    Electronic Resource
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 50 (1992), S. 33-38 
    ISSN: 0730-2312
    Keywords: chemoprevention ; field cancerization ; intermediate biomarker ; premalignant lesions ; upper aerodigestive tract cancer ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Chemoprevention trials in lung and upper aerodigestive tract (UADT) cancer are guided by the field cancerization hypothesis. Inhaled carcinogens place the entire epithelial lining at risk for the development of cancer. The hypothesis is supported by the occurrence of premalignant lesions, such as leukoplakia or squamous metaplasia, and multiple primary tumors within the field. The concept of carcinogenesis as a multistep process suggests the possibility of blocking or reversing the progression to invasive cancer with systemic treatment. A series of ongoing clinical trials will determine the efficacy of retinoid chemoprevention and will attempt to develop intermediate biomarkers. Biomarkers which reliably reflect progression towards cancer could be used to dramatically improve the efficiency of chemoprevention trials and also would aid in screening potential chemoprevention agents. Genomic biomarkers include non-specific estimates of ongoing DNA injury, such as micronuclei, as well as development of aneuploidy and alterations in oncogenes. A class of biomarkers of increasing importance assess proliferation and growth regulation, and include proliferating cell nuclear antigen (PCNA), TGF-β, EGFR and retinoid receptors. Other markers, such as the blood group antigens, reflect differentiation and may be associated with the development of premalignant lesions. Preliminary data from several of these markers has suggested and association with carcinogenic exposures and premalignant lesions, but none of these markers either alone or in panels have yet been validated as a reliable surrogate for the development of invasive cancer. © 1992 Wiley-Liss, Inc.
    Additional Material: 1 Tab.
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  • 2
    Electronic Resource
    Electronic Resource
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 53 (1993), S. 250-254 
    ISSN: 0730-2312
    Keywords: chemoprevention ; intermediate markers ; micronuclei ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Because they may be used as a quantifiable estimate of the extent of recent DNA injury, micronuclei, extrachromosomal fragments of DNA, are among the most studied potential intermediate markers of cancer chemoprevention. Serial measurements of micronuclei frequency may be easily performed on scrapings from the oral cavity or on bronchial brushings. Assessment of micronuclei frequency and its response to chemopreventive agents has been incorporated into studies of upper aerodigestive tract and lung cancer chemoprevention. These studies have helped define the characteristics of micronuclei and have suggested a role for this test in future chemoprevention studies. Micronuclei frequency has been shown to be increased in the oral and bronchial mucosa of individuals with known carcinogen exposure and is higher at the site of the greatest carcinogen exposure, such as the site where tobacco quids are held, than in grossly normal-appearing mucosa. Treatment with chemopreventive agents leads to a reduction in micronuclei frequency. In oral leukoplakia studies, this effect followed treatment with β-carotene, retinol, α-tocopherol, and 13-cis-retinoic acid. The multistep process of epithelial carcinogenesis results from DNA damage and specific genetic events. That micronuclei reflect ongoing DNA injury suggests the hypothesis that long term suppression of cellular genotoxicity, as reflected by a reduction in micronuclei frequency, ultimately leads to a reduction in cancer incidence.
    Additional Material: 1 Tab.
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  • 3
    Electronic Resource
    Electronic Resource
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 63 (1996), S. 57-62 
    ISSN: 0730-2312
    Keywords: cancer risk ; genetic instability ; in situ hybridization ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Many human tumors are thought to develop along a multistep pathway in tissues that have encountered long periods of carcinogen exposure and thus have accumulated genetic hits in functional targets relevant to tumor evolution. The cumulative degree of genetic change is dependent on both exogenous (e.g., degree of carcinogen exposure) and endogenous factors (e.g., metabolism of procarcinogens, repair or misrepair capacity, proliferation properties of the tissue, capability of damaged cells to survive). Thus one approach to risk estimation is to measure the accumulated amount of genetic damage in a target tissue at risk for tumor development. Since one cannot predict the exact site of the future tumor, the risk assay must detect a generalized ongoing process of genetic instability from small, random biopsies. The technique of chromosome in situ hybridization involves the use of chromosome- or region-specific probes and provides an ability to directly visualize genetic change (e.g., random or clonal chromosome polysomy and monosomy) on thin tissue sections (where tissue architecture is maintained) or exfoliated cells. Analyses of normal and premalignant lesions adjacent to tumors (e.g., head and neck, lung, bladder, cervix, breast) have demonstrated that chromosome instability can be detected in the field of the tumor (i.e., in normal and premalignant cells in a tissue at 100% risk of tumor development) and the degree of chromosome instability increases with the degree of histologic progression toward cancer. Analyses of premalignant lesions (e.g., oral leukoplakia and erythroplakia from individuals at risk for aerodigestive tract cancer) by chromosome in situ hybridization have uncovered varying degrees of chromosome instability. However, approximately half of those individuals who showed a high degree of chromosome instability in biopsies subsequently developed aerodigestive tract cancer. Of interest, half of these tumors have developed away from the biopsied site, suggesting that the detection of a chromosome instability process in one aspect of the tissue might yield risk information for the total tissue field. These studies also suggest that chromosome in situ hybridization might be useful for identifying individuals with high tumor risk who might benefit from chemopreventive intervention. J. Cell. Biochem. 25S:57-62. © 1997 Wiley-Liss, Inc.
    Additional Material: 2 Ill.
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  • 4
    Electronic Resource
    Electronic Resource
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 59 (1995), S. 1-10 
    ISSN: 0730-2312
    Keywords: Breast cancer ; carcinogenesis ; cervical cancer ; chemoprevention ; head and neck cancer ; lung cancer ; skin cancer ; retinoids ; retinoid receptors ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Retinoids, which include natural vitamin A (retinol) and its esters and synthetic analogues, are the best-studied class of agents in chemoprevention. There are more than 4,000 different retinoids which have a wide spectrum of preclinical activities, structures, pharmacological profiles, tissue distributions, receptor specificities, and toxicities. A number of retinoids have significant activity in many in vivo experimental systems including skin, bladder, lung, breast and oral carcinogenesis. In clinical trials, several retinoids have achieved significant activity in the reversal of head and neck, skin, and cervical premalignancy, and in the prevention of second primary tumors associated with head and neck, skin, and non-small cell lung cancer. Since 1984, our group has conducted a series of clinical trials to explore the chemopreventive potential of 13-cis-retinoic acid (13cRA) in the aerodigestive tract. We have conducted two consecutive randomized studies in subjects with premalignant lesions of the oral cavity. These studies showed that high-dose 13cRA alone can achieve significant short-term reversal of oral premalignancy, and that high-dose followed by low-dose 13cRA can maintain suppression of oral carcinogenesis. Three other randomized trials have confirmed significant retinoid activity in this human carcinogenic system. We also developed a randomized, placebo-controlled trial of adjuvant high-dose 13cRA in patients with head and neck cancer. Second primary tumor development was significantly decreased in the 13cRA group, but 13cRA had no impact on primary disease recurrence or survival. This presentation will update the current status of clinical trials and correlative laboratory studies of potential intermediate endpoint biomarkers in retinoid chemoprevention of aerodigestive tract carcinogenesis.
    Additional Material: 2 Ill.
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  • 5
    ISSN: 0897-3806
    Keywords: open heart surgery ; venous collateralization ; myocardial protection ; Life and Medical Sciences ; Miscellaneous Medical
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Fifteen consecutive patients having open heart surgery using retrograde cardioplegia were studied to demonstrate that important venous collateralization exists between the coronary sinus (CS) and its left ventricular branches and the right ventricle (RV). The venous collateralization makes possible RV myocardial protection during retrograde cardioplegia. Right ventricular venous drainage principally occurs via anterior cardiac veins, which drain into the right atrium, and thebesian veins, which drain into both the RV and the atrium, generally without connection to the CS. Retrograde cardioplegia used during open heart surgery should, therefore, give inadequate myocardial protection to the RV. Two RV temperature probes used as markers for RV perfusion were monitored continuously during cardiac arrest. Systemic temperature while on cardiopulmonary bypass was 25°C, and the retrograde perfusate solution temperature was 4°C. Coronary sinus pressure during the bypass procedure was maintained between 20 torr and 50 torr. Mean temperatures at the two probe sites were 16.1°C and 14.5°C. We conclude that a complex network of venous collaterals between the coronary sinus and left ventricle and the right ventricle allow excellent myocardial protection during retrograde cardioplegia. © 1994 Wiley-Liss, Inc.
    Additional Material: 4 Ill.
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  • 6
    Electronic Resource
    Electronic Resource
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 36 (1988), S. 275-287 
    ISSN: 0730-2312
    Keywords: cytochrome oxidase ; subunit Va ; in vitro mutagenesis ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: In order to facilitate studies on protein localization to and sorting within yeast mitochondria, we have designed an experimental system that utilizes a new vector and a functional assay. The vector, which we call an LPS plasmid (for leader peptide substitution), employs a yeast COX5a gene (the structural gene for subunit Va of the inner membrane protein complex cytochrome c oxidase) as a convenient reporter for correct mitochondrial localization. Using in vitro mutagenesis, we have modified COX5a so that the DNA sequences encoding the wild-type subunit Va leader peptide can be precisely deleted and replaced with a given test sequence. The substituted leader peptide can then be analyzed for its ability to direct subunit Va to the inner mitochondrial membrane (to target and sort) by complementation or other in vivo assays. In this study we have tested the ability of several heterologous sequences to function in this system. The results of these experiments indicate that a functional leader peptide is required to target subunit Va to mitochondria. In addition, leader peptides, or portions thereof, derived from proteins located in other mitochondrial compartments can also be used to properly localize this polypeptide. The results presented here also indicate that the information necessary to sort subunit Va to the inner mitochondrial membrane does not reside in the leader peptide but rather in the mature subunit Va sequence.
    Additional Material: 5 Ill.
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 138 (1989), S. 61-69 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Changes in the packing of phospholipids in the plasma membrane of lymphocytes occur during differentiation within primary and secondary lymphoid organs. As they differentiate, lymphocytes interact with a variety of reticuloendothelial cells, including macrophages. To investigate a possible relation between these two phenomena, the strength of the interactions between lymphocytes and macrophages was measured in vitro as a function of the tightness of packing of phospholipids on the lymphocyte surface. Strength of adherence was measured by the ability of lymphocytes to remain adherent to macrophages when subjected to increasing centrifugal forces. Phospholipid packing was assessed using the fluorescent lipophilic probe merocyanine 540 (MC540), which preferentially binds to bilayers in which the lipids are more loosely packed. Three subpopulations of murine thymocytes were resolved with respect to strength of adherence to peritoneal or thymic macrophages. To determine whether these subpopulations corresponded with the three classes of cells distinguishable by MC540 fluorescence, populations enriched for staining or non-staining cells, and cells sorted on the basis of MC540 fluorescence intensity, were examined. The least fluorescent cells were the least strongly adherent; the most fluorescent cells were the most strongly adherent; and cells of intermediate fluorescence had intermediate adherence. When splenic lymphocytes were examined with respect to adherence to peritoneal or splenic macrophages, similar patterns of fluorescence and adherence were seen. These results suggest that the organization of the plasma membrane lipid bilayer of lymphocytes may be involved in their interactions with macrophages during primary and secondary differentiation. The adherence signal for lymphocytes thus may be similar to that proposed for other blood cells.
    Additional Material: 8 Ill.
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Yeast 13 (1997), S. 119-125 
    ISSN: 0749-503X
    Keywords: Saccharomyces cerevisiae ; glycolysis ; metabolism ; glucose ; trehalose ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Intracellular metabolic flux has been investigated in two strains of Saccharomyces cerevisiae grown into stationary phase under both glucose-repressed and glucose-derepressed conditions. By employing a variety of simple methodologies (manometry, enzymatic analysis and colorimetric analysis) we have been able to identify and quantitate carbon flow from glucose without the need for isotopically labelled substrate. We can account for 88-98% (depending on strain and growth conditions) of the carbon products of glucose metabolism under both glycolytic and oxidative conditions as ethanol (27-40%), carbon dioxide (15-26%), acetate (2-3%), glycerol (5-11%), glycogen (5-13%) and trehalose (9-39%).©1997 John Wiley & Sons, Ltd.
    Additional Material: 1 Ill.
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  • 9
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    BioEssays 15 (1993), S. 741-748 
    ISSN: 0265-9247
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Recent progress in the study of short-distance (cell-to-cell) movement of plant virus, facilitated by ‘movement proteins’, has led to a resurgence of interest in long-distance virus transport in the phloem. Relatively little is known about phloem-specific barriers to virus movement or about the form in which virus enters, travels within and exits this tissue. Progress in understanding virus and photoassimilate transport is limited by a paucity of information on the substructure and properties of plasmodesmata at specific interfaces. The direction of virus movement, once it has entered the phloem, can be understood by following photoassimilate translocation, a complex and dynamic process influenced by plant growth, development and vascular topology.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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