1
|
Kaizer B, Weissman L, Perry A, Zchut T, Fishman I, Rodnizki J, Eizenshtat M, Farber E. High power high voltage bias-T for half wave resonators and radio frequency quadrupole couplers. Rev Sci Instrum 2022; 93:053304. [PMID: 35649795 DOI: 10.1063/5.0086965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 05/03/2022] [Indexed: 06/15/2023]
Abstract
High power high voltage bias-T units capable of delivering up to 100 kW CW RF power at 176 MHz and up to 4 kV DC were developed at the Soreq Nuclear Research Center for the Soreq Applied Research Accelerator Facility linac. Two separate bias-T units with different requirements were designed for the radio frequency quadrupole couplers and the half wave resonator couplers. The purpose of this bias-T is to prevent multipacting phenomena by application of a high voltage DC bias to inner conductors of RF couplers. Underlying design principles, indigenous development, and successful off-line and on-line tests results are presented.
Collapse
Affiliation(s)
- B Kaizer
- Soreq Nuclear Research Center, Yavne, Israel
| | - L Weissman
- Soreq Nuclear Research Center, Yavne, Israel
| | - A Perry
- Soreq Nuclear Research Center, Yavne, Israel
| | - T Zchut
- Soreq Nuclear Research Center, Yavne, Israel
| | - I Fishman
- Soreq Nuclear Research Center, Yavne, Israel
| | - J Rodnizki
- Soreq Nuclear Research Center, Yavne, Israel
| | | | - E Farber
- Department of Electrical and Electronic Engineering and Department of Physics, Ariel University, Ariel, Israel
| |
Collapse
|
2
|
Beauchamp G, Rosentel J, Farber E, Levi J, Laubach L, Crowley L, MacKenzie R, Richardson D, Greenberg M. 332 Feasibility of Implementation of an Emergency Department Discharge Opioid Taper Protocol. Ann Emerg Med 2019. [DOI: 10.1016/j.annemergmed.2019.08.291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
3
|
Xu H, Huang X, Riserus U, Cederholm T, Lindholm B, Arnlov J, Carrero JJ, Leiba A, Vivante A, Bulednikov Y, Golan E, Skorecki K, Shohat T, Mjoen G, Zannad F, Jardine A, Schmieder R, Fellstrom B, Holdaas H, Zager P, Miskulin D, Gassman J, Kendrick C, Ploth D, Jhamb M, Jankowski V, Schulz A, Mischak H, Zidek W, Jankowski J, Lee YK, Cho A, Kim JK, Choi MJ, Kim SJ, Yoon JW, Koo JR, Kim HJ, Noh JW, Itano S, Satoh M, Kidokoro K, Sasaki T, Kashihara N, Koutroumpas G, Sarafidis P, Georgianos P, Karpetas A, Protogerou A, Syrganis C, Malindretos P, Raptopoulou K, Panagoutsos S, Pasadakis P, Zager P, Miskulin D, Gassman J, Kendrick C, Jhamb M, Ploth D, Vink EE, De Boer A, Verloop WL, Spiering W, Voskuil M, Vonken EJ, Hoogduin JM, Leiner T, Bots ML, Blankestijn PJ, Sarafidis PA, Karpetas AV, Georgianos PI, Bikos A, Sklavenitis-Pistofidis R, Tzimou R, Raptis V, Vakianis P, Tersi M, Liakopoulos V, Lasaridis AN, Protogerou A, Ribeiro S, Fernandes J, Garrido P, Sereno J, Vala H, Bronze Da Rocha E, Belo L, Costa E, Reis F, Santos-Silva A, Kalaitzidis R, Skapinakis P, Karathanos V, Karasavvidou D, Katatsis G, Pappas K, Hatzidakis S, Siamopoulos K, Margulis F, Sabbatiello R, Castro C, Ramallo S, Martinez M, Schiavelli R, Ganem D, Nakhoul F, Roth A, Farber E, Kim CS, Kim HY, Kang YU, Choi JS, Bae EH, Ma SK, Kim SW, Koutroumpas G, Sarafidis P, Georgianos P, Karpetas A, Protogerou A, Malindretos P, Syrganis C, Tzanis G, Panagoutsos S, Pasadakis P, Jankowski M, Kasztan M, Kowalski R, Piwkowska A, Rogacka D, Szczepa Ska-Konkel M, Angielski S, Evangelou D, Naka K, Kalaitzidis R, Lakkas L, Bechlioulis A, Gkirdis I, Nakas G, Zarzoulas F, Kotsia A, Balafa O, Tzeltzes G, Pappas K, Katsouras C, Dounousi E, Michalis L, Siamopoulos K, Maciorkowska D, Zbroch E, Koc-Zorawska E, Malyszko J, Karabay Bayazit A, Yuksekkaya I, Aynaci S, Anarat A, Nakai K, Fujii H, Ishida R, Utaka C, Awata R, Goto S, Ito J, Nishi S, Elsurer R, Afsar B, Lepar Z, Radulescu D, David C, Peride I, Niculae A, Checherita IA, Ciocalteu A, Sungur CI, Kanbay M, Siriopol D, Nistor I, Elcioglu OC, Telci O, Johnson R, Covic A, Vettoretti S, Gallazzi E, Meazza R, Gagliardi V, Villarini A, Alfieri CM, Floreani R, Messa P, Vettoretti S, Alfieri CM, Gallazzi E, Gagliardi V, Villarini A, Meazza R, Floreani R, Messa P, Kotovskaya Y, Villevalde S, Kobalava Z, Circiumaru A, Rusu E, Zilisteanu D, Atasie T, Cirstea F, Ecobici M, Voiculescu M, Rosca M, Tanase C, Baoti I, Vidjak V, Prka in I, Bulum T, Arslan E, Sarlak H, Cakar M, Demirbas S, Akhan M, Kurt O, Balta S, Yesilkaya S, Bulucu F, Chan CK, Lin YH, Wu VC, Wu KD, De Beus E, Bots ML, Van Zuilen AD, Wetzels JF, Blankestijn PJ, Mohaupt M, Straessle K, Baumann M, Raio L, Sirbek D, Nascimento MA, Mouro MG, Punaro GR, Mello MT, Tufik S, Higa EMS. HYPERTENSION. Nephrol Dial Transplant 2014. [DOI: 10.1093/ndt/gfu142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
|
4
|
Chance S, Bakeman R, Kaslow N, Farber E, Burge-Callaway K. Core conflictual relationship themes in patients diagnosed with borderline personality disorder who attempted, or who did not attempt, suicide. Psychother Res 2010. [DOI: 10.1093/ptr/10.3.337] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
5
|
Abstract
Changes in enzyme activity due to induction by chemicals is an important property that can determine the type of response seen in tissues exposed to environmental chemicals. Two major types of response, acute irreversible liver cell injury or death (necrosis) and long-term cancer induction, are discussed in terms of their modulation by enzyme induction. Most commonly, enzyme induction leads to a more severe toxic response by the liver, and to more cell death. However, inducers may have a protective effect, especially in carcinogenesis, when they most frequently protect against cancer induction if used early in the process. There is a discrepancy between this observation and the increase in mutagenic activity of liver preparations observed after induction. However, when enzyme induction occurs at a later stage, after initiation, it often accelerates or promotes cancer induction. Also, new cell populations constantly observed during liver carcinogenesis are composed of very hypertrophic hepatocytes containing a large amount of smooth endoplasmic reticulum. This is associated with a radical change in enzyme activities in the reticulum, which may account in part for the characteristic resistance exhibited by initiated cells to hepatotoxins and carcinogens. The resistance is considered to be an important property that may play a key role in the development of cancer under some circumstances.
Collapse
|
6
|
Abstract
Glow discharge plasma, derived from direct-current gas breakdown, is investigated in order to realize an inexpensive terahertz (THz) room-temperature detector. Preliminary results for THz radiation show that glow discharge indicator lamps as room-temperature detectors yield good responsivity and noise-equivalent power. Development of a focal plane array (FPA) using such devices as detectors is advantageous since the cost of a glow discharge detector is approximately $0.2-$0.5 per lamp, and the FPA images will be diffraction limited. The detection mechanism of the glow discharge detector is found to be the enhanced diffusion current, which causes the glow discharge detector bias current to decrease when exposed to THz radiation.
Collapse
Affiliation(s)
- A Abramovich
- Department of Electrical and Electronic Engineering, Ariel University Center of Samaria, Ariel, Israel.
| | | | | | | |
Collapse
|
7
|
Kanduc D, Mittelman A, Serpico R, Sinigaglia E, Sinha A, Natale C, Santacroce R, Di Corcia M, Lucchese A, Dini L, Pani P, Santacroce S, Simone S, Bucci R, Farber E. Cell death: Apoptosis versus necrosis (Review). Int J Oncol 2002. [DOI: 10.3892/ijo.21.1.165] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
|
8
|
Abstract
Phenotypic resistance, acquired early in carcinogenesis, has an established role in the pathogenesis of cancer in well-characterised experimental systems, and possibly also has a role in the origin of human cancer. It has been suggested that sunlight, an established risk factor for human skin carcinogenesis, is able to induce rare altered cells resistant to toxicity and to favour their clonal expansion via toxic effects exerted on normal keratinocytes. Other major risk factors for human neoplasia, including smoking and ageing, may also act partly through imposition of a constrained growth environment in the target organ to favour the emergence of altered resistant cells. Strategies aimed at counteracting this constrained environment could be effective in attenuating the force that sustains clonal expansion of altered cells.
Collapse
Affiliation(s)
- E Laconi
- Department of Medical Sciences and Biotechnology, University of Cagliari, Italy.
| | | | | |
Collapse
|
9
|
Abstract
Our overall understanding of mechanisms of toxicology in relation to human disease, with prevention of disease as a major objective, depends in part on the development of an adequate number of ways to assess risks, both short term and long term. Despite the cost, the long duration of the test, and some pitfalls, the long-term animal tests remain, to date, the only reliable assay for possible carcinogens. Recent work has concentrated increasingly on the development of short-term tests to replace the long-term tests. Such a development would be most welcome from several points of view. To date, a variety of approaches have been or are being used. These include (1) activation to an alkylating agent with DNA as the most important target, generating possible mutations in DNA and DNA damage with or without repair, (2) induction of cell proliferation, at least a few cycles, with DNA synthesis as the major target, again favoring mutations, and (3) decrease in cell-to-cell communication (gap-junctional intercellular communication) as a supposed test for promotion. None of these proposed assays are reliable indices for possible carcinogenic effects of chemicals or other agents; the scientific basis for this negative conclusion is discussed.
Collapse
Affiliation(s)
- E Farber
- Department of Pathology and Cell Biology, University of South Carolina Medical School, Columbia 29209, USA
| |
Collapse
|
10
|
Nagai MK, Farber E. The slow induction of resistant hepatocytes during initiation of hepatocarcinogenesis by the nongenotoxic carcinogen clofibrate. Exp Mol Pathol 1999; 67:144-9. [PMID: 10600397 DOI: 10.1006/exmp.1999.2258] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This study was designed to explore whether a well-known nongenotoxic liver carcinogen, clofibrate, would induce rare resistant hepatocytes similar to those seen during initiation of hepatocarcinogenesis with many genotoxic carcinogens. Male young adult F344 rats were exposed to a control diet containing 0.5% (w/w) clofibrate for 3, 6, or 10 months. After 1 month on a diet free of clofibrate, the animals were assayed for resistant hepatocytes by a standardized selection procedure using 2-acetylaminofluorene as the inhibitor and partial hepatectomy as a strong stimulus for cell proliferation. No resistant hepatocytes were found in the animals exposed to clofibrate for 3 months or in any of a series of control animals. However, animals on the clofibrate for 6 and 10 months contained resistant hepatocytes that were clonally expanded to produce hepatocyte nodules. These nodules were indistinguishable on gross and microscopic examination from hepatocyte nodules seen in animals in which nodules are induced with one of many different genotoxic carcinogens. Also, like those nodules, the nodules seen in the animals exposed to clofibrate stained positively for glutathione S-transferase 1-1 and gamma-glutamyl transpeptidase and negatively for ATPase. The evidence from this study indicates that the nongenotoxic carcinogen, clofibrate, induces early cellular changes in the liver that are very similar to those induced by many different genotoxic carcinogens. These changes are manifest as a resistance phenotype in a few scattered hepatocytes that now can be clonally expanded selectively to form hepatocyte nodules. However, the resistant hepatocytes are induced by clofibrate much more slowly. Whether this basic similarity pertains to the later steps in the hepatocarcinogenic process remains to be studied.
Collapse
Affiliation(s)
- M K Nagai
- Department of Pathology and Department of Biochemistry, University of Toronto School of Medicine, Medical Science Building, Toronto, Ontario, M5S 1A8, Canada
| | | |
Collapse
|
11
|
Kanduc D, Bannasch P, Farber E. A critical perspective in cancer research (Review). Int J Oncol 1999; 15:1213-20. [PMID: 10568830 DOI: 10.3892/ijo.15.6.1213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Over the past few decades, there has been a tremendous increase in cancer biology data and treatment. Cancer research has opened exciting new areas of cellular and molecular biology. Month by month, new genes which regulate the carcinogenesis process are being discovered. The result is an incredible knowledge of cancer: what makes a cancer cell a cancer cell, what cancer cells need to develop, and how cancer cells behave, interact, overgrow and die. In parallel, gene manipulation within cells lets us foresee future possibilities of new cancer treatments. On the other hand, this combination of increased knowledge and powerful new techniques has provided no effective cancer therapy. As it has been quoted during the <Update and Intensive Review of Internal Medicine> meeting held in New York, August 1999: <. The success in treating Hodgkin's disease means that patients now live enough to develop complications related to the treatment>. Thus, after dedicated decades of excellent research, cancer remains a significant human, clinical, and economical burden. The purpose of this review is 2-fold. First, to analyze areas of basic cancer research that still await adequate scientific explanations. Second, to stress that, for its continuing advancement, cancer research is dependent upon close relationships among many disciplines; an intimate alignment of oncologists with biochemists, geneticists, immunologists, experimental pathologists, and pharmacologists is needed. In light of the great success registered at the basic science level but lack of effective therapies, it would be wise to establish human and economical resources addressed to a multidisciplinary collaborative effort in cancer research.
Collapse
Affiliation(s)
- D Kanduc
- Department of Biochemistry and Molecular Biology, University of Bari, I-70126 Bari, Italy
| | | | | |
Collapse
|
12
|
Jacobson MF, Farber E, Clapp R. Re: Long-term feeding of sodium saccharin to nonhuman primates: implications for urinary tract cancer. J Natl Cancer Inst 1998; 90:934-6. [PMID: 9637144 DOI: 10.1093/jnci/90.12.934] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
|
13
|
Affiliation(s)
- E Farber
- Thomas Jefferson University, Jefferson Medical College, Department of Pathology, Anatomy, and Cell Biology, Philadelphia, Pennsylvania 19107, USA
| |
Collapse
|
14
|
Farber E. Investigative toxicologic pathology in safety assessment--a commentary. Toxicol Pathol 1997; 25:660-1. [PMID: 9437817 DOI: 10.1177/019262339702500628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
|
15
|
Abstract
1. Premalignant rat liver nodules produced in the resistant hepatocyte model, by exposure to carcinogenic chemicals (diethyl nitrosamine and 2-acetamidofluorene), and partial hepatectomy, exhibit decreased xenobiotic hydroxylase activities and increased conjugase activities, which are considered responsible for increased resistance to xenobiotic toxicity. 2. However, premalignant rat liver nodules generated by feeding the hypolipidaemic, peroxisomal proliferating drug, ciprofibrate, in a hypolipidaemic model, exhibit decreased hydroxylase activities but decreased conjugase activities also. 3. It is considered that reactive oxygen species (ROS) are generated in both the resistant hepatocyte model and in the hypolipidaemic model, resulting in lipid peroxidation, loss of haem, cytochromes and hydroxylase activities. 4. However, whereas there is a rebounding compensation of conjugase enzymes in the resistant hepatocyte model, this does not occur with the hypolipidaemic model, as peroxidation is probably persistent and the conjugases are continuously destroyed.
Collapse
Affiliation(s)
- M W Roomi
- Department of Pathology, University of Toronto, Canada
| | | | | |
Collapse
|
16
|
Abstract
BACKGROUND Chordomas are tumors of notochordal origin that account for approximately 1%-4% of all primary malignant bone tumors. The majority of patients with chordomas have a poor surgical prognosis due to extent of disease at diagnosis. These lesions have been previously classified based solely on their location. METHODS We describe here a case report of a posterior epidural C5-T1 chordoma that was discovered in a young patient who presented with weakness and paresthesia in all four extremities. This lesion was notable for its extraosseous and extradural characteristics. RESULTS C5-T1 laminectomy with gross total resection of the mass led to complete resolution of all symptoms. There has been no evidence of tumor recurrence to date. CONCLUSIONS We propose here a new classification system for chordomas that emphasizes the difference in resectability of these lesions depending on the space they occupy and the presence or absence of an osseous connection.
Collapse
Affiliation(s)
- J Jallo
- Temple University School of Medicine, Philadelphia, Pennsylvania 19146, USA
| | | | | | | |
Collapse
|
17
|
Farber E. Monoclonal and polyclonal development of digestive tract tumors in chimeric mice. Jpn J Cancer Res 1997; 88:inside front cover. [PMID: 9119735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Affiliation(s)
- E Farber
- Department of Pathology, Anatomy & Cell Biology, Thomas Jefferson University, Philadelphia, PA, USA
| |
Collapse
|
18
|
Farber E. Cell proliferation is not a major risk factor for cancer. Mod Pathol 1996; 9:606. [PMID: 8782195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
|
19
|
Farber E. Alcohol and other chemicals in the development of hepatocellular carcinoma. Clin Lab Med 1996; 16:377-94. [PMID: 8792078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
A positive association between the incidence of hepatocellular carcinoma and the consumption of alcoholic beverages has been reported from some countries. The possible mechanistic nature of the association remains unclear, however. The effects of alcohol, as ethanol and as ethanol in various complex mixtures in the many different alcoholic beverages, were compared with the effects of well-known genotoxic and nongenotoxic or epigenetic carcinogens in carcinogenesis. There is no convincing evidence that alcohol can initiate the long multistep process of development of hepatocellular carcinoma. Thus, it appears that alcohol cannot be considered as a complete carcinogen. The effects of alcohol were also compared with known promoting agents for liver cancer. Although the available data are less clear, nevertheless it appears that alcohol cannot be considered as a bona fide promoting agent for liver cancer development. The most likely roles of alcohol in the genesis of liver cancer are: (1) to induce a well-known precancerous liver lesion, cirrhosis, and (2) to modulate, in an as yet ill-defined manner, the process of cancer development with known human carcinogenic influences such as hepatitis due to hepatitis B and hepatitis C viruses. Alcohol is well known to induce several enzymes in the liver and, thus, could theoretically modulate one or more steps in the carcinogenic process. Because alcohol has been found to alter cell membranes in well-defined ways and cell membrane changes, especially in the liver endoplastic reticulum, appear to be common in the later steps in liver cancer development, it is suggested that one site of alcohol action might be in the modulation of the biophysical composition of the liver endoplasmic reticulum and plasma membrane, favoring the cellular evolution to neoplasia.
Collapse
Affiliation(s)
- E Farber
- Department of Pathology, Anatomy, and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| |
Collapse
|
20
|
Kanduc D, Pagano G, Farber E. Changes in tRNA pattern in ethionine-induced rat putative preneoplastic hepatocyte nodules. Biochem Mol Biol Int 1996; 38:1191-7. [PMID: 8739041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
As part of a study to explore further the biochemical pathology of chemical hepatocarcinogenesis, cytoplasmic tRNA patterns have been studied in ethionine-induced rat putative preneoplastic nodules in comparison to surrounding non-nodular liver and control liver. A new h.p.l.c. methodology, able to resolve contemporaneously the numerous components in a tRNA population, has been used. The results obtained indicate the presence of marked differences in the chromatographic profiles of hepatocyte nodules, non-nodular surrounding liver and control liver. The differences are both quantitative and qualitative, with some chromatographic peaks showing increases and some decreases or absences. Also, new peaks are seen reproducibly in the nodules. The data show major changes in the tRNA population during hepatocarcinogenesis that might have mechanistic implications.
Collapse
Affiliation(s)
- D Kanduc
- Dept. of Biochemistry and Molecular Biology, University of Bari, Italy
| | | | | |
Collapse
|
21
|
Affiliation(s)
- E Farber
- Department of Pathology, Anatomy & Cell Biology, Thomas Jefferson, University, Philadelphia, Pennsylvania 19107, USA
| |
Collapse
|
22
|
Draper HH, Agarwal S, Nelson DE, Wee JJ, Ghoshal AK, Farber E. Effects of peroxidative stress and age on the concentration of a deoxyguanosine-malondialdehyde adduct in rat DNA. Lipids 1995; 30:959-61. [PMID: 8538385 DOI: 10.1007/bf02537489] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The effect of age and peroxidative stress on the concentration of a deoxyguanosine malondialdehyde adduct (dG-MDA) in rat tissues was investigated. Vitamin E deficiency had no effect on the dG-MDA content of liver DNA in rats fed a diet containing 10% corn oil. When 2% cod liver oil was added to this diet, the dG-MDA content of liver DNA doubled in the positive controls fed a high level of vitamin E (100 ppm dl-alpha-tocopherol), and there was a further increase when vitamin E was deleted. Neither iron nitrilotriacetate administration nor choline deficiency had any effect on the dG-MDA content of liver DNA. Carbon tetrachloride had a lowering effect. The failure of iron or carbon tetrachloride administration and of vitamin E deficiency to increase liver dG-MDA is consistent with their failure in previous experiments to affect the urinary excretion of dG-MDA. In contrast, these forms of peroxidative stress produce large increments in the urinary excretion of MDA adducts with lysine, reflecting increased formation and degradation of MDA-modified proteins. DNA appears to be protected from modification by MDA produced at extranuclear sites. The frequency of dG-MDA in different tissues of 4-month-old rats varied markedly: brain >> liver > kidneys and testes. Higher concentrations of dG-MDA were found in the liver and kidneys, but not the testes, of 25-month-old rats. The determinants of the concentration of dG-MDA in DNA merit further investigation.
Collapse
Affiliation(s)
- H H Draper
- Department of Nutritional Sciences, University of Guelph, Ontario, Canada
| | | | | | | | | | | |
Collapse
|
23
|
Farber E. Cell proliferation as a major risk factor for cancer: a concept of doubtful validity. Cancer Res 1995; 55:3759-62. [PMID: 7641190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- E Farber
- Department of Pathology, University of Toronto, Ontario, Canada
| |
Collapse
|
24
|
Ghoshal AK, Farber E. Liver biochemical pathology of choline deficiency and of methyl group deficiency: a new orientation and assessment. Histol Histopathol 1995; 10:457-62. [PMID: 7599441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
New information on the pathologic effects of a choline deficient diet in the rat, in relation to the biochemical events, has led to a new understanding and orientation of the pathogenesis of both acute and chronic consequences in the liver. The biochemical pathology of choline deficiency is quite different than that of methyl group (lipotrope) deficiency. These studies in our laboratory and elsewhere are generating new insights and hypotheses concerning the genesis of hepatocyte necrosis and hepatocellular carcinoma in the rat fed a choline deficient diet.
Collapse
Affiliation(s)
- A K Ghoshal
- Department of Pathology, University of Toronto, Ontario, Canada
| | | |
Collapse
|
25
|
Gindi T, Ghazarian DM, Deitch D, Farber E. An origin of presumptive preneoplastic foci and nodules from hepatocytes in chemical carcinogenesis in rat liver. Cancer Lett 1994; 83:75-80. [PMID: 8062236 DOI: 10.1016/0304-3835(94)90301-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The sites and times of appearance of preneoplastic foci in rat liver acinus during the first 11 days after initiation with diethylnitrosamine and promotion with 2-acetylaminofluorene plus partial hepatectomy was observed in three separate experiments. Foci appeared as alterations of hepatocytes followed by focal proliferation in each of the three zones before any ductular epithelial cell ('oval cell') proliferation. The dissociation between foci and 'oval cell proliferation' is strong evidence against a role of the latter in generating preneoplastic hepatocytes in hepatocellular carcinogenesis.
Collapse
Affiliation(s)
- T Gindi
- Department of Pathology, University of Toronto, Ontario, Canada
| | | | | | | |
Collapse
|
26
|
Abstract
Changes in the degree of methylation of cytosine in DNA are considered to be mechanistically important in modulating gene expression. To gain a better understanding of the relationship(s) linking onco-proliferative processes and enzymatic DNA methylation, a study has been carried out on the hepatic DNA methylation pattern during DNA replication following partial hepatectomy (PH), mitogen treatment and N-methyl-N-nitrosourea (MNU) administration in rats. The following results were obtained: (i) DNA hypomethylation was seen during DNA synthesis, with each of the 3 stimuli, namely MNU administration, partial hepatectomy, and hepatomitogen treatment; (ii) the level of DNA hypomethylation was not quantificatively related to the extent of DNA replication as measured by incorporation of [3H]thymidine into hepatic DNA; (iii) MNU administration under conditions conducive to carcinogenic development, i.e. during the S phase of compensatory cell proliferation, caused hypermethylation of replicating hepatic DNA, as shown by HpaII and MspI restriction patterns.
Collapse
Affiliation(s)
- D Kanduc
- Department of Biochemistry and Molecular Biology, Faculty of Sciences, University of Bari, Italy
| | | | | |
Collapse
|
27
|
Farber E. Programmed cell death: necrosis versus apoptosis. Mod Pathol 1994; 7:605-9. [PMID: 7937727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Cell death remains poorly understood, despite its obvious importance in every organ and tissue in a wide variety of biological processes, including, of course, the many pathological. The past few years have seen an amazing expansion of interest in cell death in normal development and maturation, in the pathogenesis of many acute and chronic diseases, and in the therapy of some diseases, especially malignant neoplastic diseases and some hyperplastic diseases such as psoriasis. This expansion has included an unusual interest in a supposedly new form of cell death, a "programmed cell death," designated "apoptosis." This is proposed as a hitherto undescribed form of cell death in contrast to the classical cell death, necrosis. Apoptosis is considered by some, especially by nonpathologists, to represent quite a different type of cell death. A review of the literature on on apoptosis, programmed cell death, necrosis, etc. indicates that there is no field of basic cell biology and cell pathology that is more confusing and more unintelligible than the area of apoptosis versus necrosis. If any degree of clarity is to develop in our understanding of the fundamental principles underlying cell death of any type, it is incumbent upon us to rethink "from square one" the scientific analysis of how cells die and how can we assess cell death in a reasonably rational manner.
Collapse
Affiliation(s)
- E Farber
- Department of Pathology, University of Toronto, Ontario, Canada
| |
Collapse
|
28
|
Koo P, Nagai MK, Farber E. Multiple sites of control of glutathione S-transferase P1-1 in rat liver. J Biol Chem 1994; 269:14601-6. [PMID: 8182066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Glutathione transferase P1-1, normally very low in adult rat liver, is induced by a single intravenous dose of lead nitrate. In this transient induction, there are at least three sites of regulation or control. These are transcription, post-transcription, and post-translation. The increase in transcription is evident both by nuclear run-off analysis and by measurement of mRNA levels. The other two sites of control were seen in actinomycin D-treated animals in which RNA synthesis was inhibited by over 80%. Treatment with actinomycin D increases the stability of the mRNA and also somehow inhibits the conversion of a glutathione transferase protein to an enzymatically active form. These three sites offer possibilities for the study of mechanisms of control for this interesting enzyme that may play a role in chemical carcinogenesis and in drug resistance.
Collapse
Affiliation(s)
- P Koo
- Department of Pathology, University of Toronto, Ontario, Canada
| | | | | |
Collapse
|
29
|
|
30
|
Habib SL, Srikanth NS, Scappaticci FA, Faletto MB, Maccubbin A, Farber E, Ghoshal AK, Gurtoo HL. Altered expression of cytochrome P450 mRNA during chemical-induced hepatocarcinogenesis and following partial hepatectomy. Toxicol Appl Pharmacol 1994; 124:139-48. [PMID: 8291055 DOI: 10.1006/taap.1994.1017] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Levels of various cytochrome P450 proteins have been reported to be decreased to varying degrees in chemically induced hepatocyte nodules and following partial hepatectomy (PH). By screening a rat liver lambda ZAP cDNA expression library with antibodies raised against a partially purified preparation of cytochrome P450 isolated from untreated male Fischer 344 rats, we have isolated a 1.1-kb cDNA. This cDNA was sequenced for 139 bases from the 5' end of the sense strand and comparison of the resulting sequence with the sequences in Gene Man DNA data bank revealed 95% homology of the sequenced portion with male-specific rat cytochrome P450 (M-1, CYP IIC11). The 32P-labeled cDNA was used as a hybridization probe on RNA blots (Northern blots) prepared with total RNA from rat livers obtained post PH, from aflatoxin B1(AFB1)-induced rat liver tumors and from rat liver nodules induced with a combination of diethylnitrosamine/acetylaminofluorene/PH (DEN/AFF/PH). At 36 and 72 hr post PH, the mRNA level was decreased by > 93%. Relative to the corresponding control livers, the mRNA level was also decreased by 97% in the liver nodules and by 57% in AFB1-induced liver tumors. The RNA blots derived from the liver nodules and AFB1-induced liver tumors were also probed with a cDNA probe (R17) that recognizes other cytochromes P450 (CYP IIB1/CYP IIB2). The mRNA corresponding to CYP IIB1/CYP IIB2 was also depressed 92% in the nodules and 65% in the tumors. These results clearly indicate that the depression of both CYP IIC11 and IIB1/IIB2 in the hepatic nodules and the tumors is related to the inhibition of transcription and/or enhanced degradation of the mRNA.
Collapse
Affiliation(s)
- S L Habib
- Grace Cancer Drug Center, Roswell Park Cancer Institute, Buffalo, New York 14263
| | | | | | | | | | | | | | | |
Collapse
|
31
|
|
32
|
Abstract
BACKGROUND Small hepatocellular carcinomas frequently were found incidentally during routine pathologic examinations of adult livers removed at liver transplant. METHODS Sixty-nine carcinomas of all sizes were found in 25 patients; 39 of the tumors were smaller than 1 cm in diameter, and 18 of the carcinomas in five patients were not clinically suspected. These small incidental carcinomas lend themselves to analysis of the morphologic basis of human hepatocellular carcinogenesis. RESULTS All of these tumors arose in cirrhotic livers. Most of the small carcinomas were multilobulated and subdivided by pre-existing fibrous septa. The surrounding capsule usually was not a true capsule. They were all well differentiated, most formed bile, Mallory bodies, or showed alpha-1-antitrypsin (A1AT) positivity. Transition from cirrhotic nodular parenchyma to areas of hyperplasia or atypical hyperplasia to well-differentiated carcinoma were common. Large cell dysplasia also was common. CONCLUSIONS These morphologic transitions closely parallel changes seen in experimental chemical carcinogenesis. They also strongly suggest a multicentric origin of the tumors. In addition, in every instance, the lesions were multiple in the liver and involved both lobes. This latter finding has possible implications for recurrence after local surgical excision of small hepatocellular carcinomas.
Collapse
Affiliation(s)
- R G Cameron
- Department of Pathology, Toronto Hospital, Ontario, Canada
| | | | | | | | | | | | | |
Collapse
|
33
|
Kanduc D, Farber E, Ghoshal A, Nagai M. Sequential alterations in tRNA population of 2-acetylaminofluorene-induced hepatocyte nodules. Biochem Biophys Res Commun 1993; 195:1309-13. [PMID: 8216263 DOI: 10.1006/bbrc.1993.2186] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
In order to investigate the possible mechanisms by which cellular alterations can start an altered onco-developmental gene expression, we studied tRNA distribution profiles during the early steps of 2-acetylaminofluorene-induced hepatocarcinogenesis. The finding of progressive and sequential alterations appears to support the hypothesis of a causal connection between tRNA changes and nodular cell proliferation, possibly through the disruption of the mechanism which regulates tRNA functional adaptation.
Collapse
Affiliation(s)
- D Kanduc
- Dept. Pathology, University of Toronto, Ontario, Canada
| | | | | | | |
Collapse
|
34
|
Ghoshal AK, Farber E. Choline deficiency, lipotrope deficiency and the development of liver disease including liver cancer: a new perspective. J Transl Med 1993; 68:255-60. [PMID: 7680728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Thus, the pathologic consequences of feeding a CD diet are fatty liver, liver cell death, liver cell proliferation, and liver cell cancer. The fatty liver with CD is similar to that with other types of fatty liver in that the most attractive current hypothesis is based on some interference with the production and output of VLDL by the liver. The induction of cell death appears to be consistent with quite a different hypothesis, genesis and/or increase in liver free radicals leading to both acute necrosis and initiation of carcinogenesis. Especially noteworthy is the low incidence of liver cirrhosis, even after 2 years of exposure to the CD diet. The feeding of the CD diet reproducibly induces severe and persistent fatty liver coupled with extensive cell death, a combination that is frequently considered to be appropriate for the induction of "micronodular" (fatty) cirrhosis in humans. The findings with the LD diet, the high incidence of cirrhosis, with severe persistent fatty liver without significant cell death, together with the low incidence of cirrhosis with the CD diet, stand out as unpredictable and strange, according to current concepts of the pathogenesis of human cirrhosis. The CD model offers an unusual opportunity to explore in increasing detail the possible roles of free radicals in two important problems in pathology and medicine-acute cell injury and neoplasia. The challenges include mechanistic studies on how the free radicals are generated and how they relate to the biological consequences. The relatively slow sequential changes in the induction of cell injury and neoplasia makes the CD model one of the best for mechanistic studies relating to free radicals.
Collapse
Affiliation(s)
- A K Ghoshal
- Department of Pathology, University of Toronto, Ontario, Canada
| | | |
Collapse
|
35
|
Abstract
The dominant dogma concerning the essential cellular changes during preneoplasia and precancer considers these as abnormal or foreign that evoke a basic "host-parasite" response. An alternative view of how cancer develops, here briefly outlined, views the early and intermediate cellular changes as essentially physiologic and adaptive. This different concept introduces clonal adaptation as a basic response to many genotoxic carcinogenic stimuli including chemicals, radiations, and some viruses. The evidence in support of this new view of the carcinogenic process is summarized.
Collapse
Affiliation(s)
- E Farber
- Department of Pathology, University of Toronto, Ontario, Canada
| |
Collapse
|
36
|
Kanduc D, Aresta A, Quagliariello E, Farber E. Effect of MNU on the methylation pattern of hepatic DNA during compensatory cell proliferation. Biochem Biophys Res Commun 1992; 184:107-11. [PMID: 1567416 DOI: 10.1016/0006-291x(92)91164-l] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
We have used the initiation-promotion model of MNU-induced hepatocarcinogenesis to test the hypothesis that alteration of the methylation status of DNA cytosines could be involved in the initiation of carcinogenesis. In fact cell proliferation plays a fundamental role in the initiation of liver carcinogenesis and hepatocytes in the S phase are more sensitive towards MNU initiation than at other times in the cycle. The molecular mechanisms involved in these processes, however, are still poorly understood and it seemed of value to monitor the DNA methylation status in this system. The results obtained indicate that MNU hepatocarcinogenic action might consist also of the inhibition of DNA hypomethylation biologically associated with cell proliferation.
Collapse
Affiliation(s)
- D Kanduc
- Dept. of Biochemistry and Molecular Biology, Faculty of Science, University of Bari, Italy
| | | | | | | |
Collapse
|
37
|
Abstract
The cancer-initiating potential of the fumonisin B (FB) mycotoxins produced by Fusarium moniliforme was screened in rat liver for their ability to induce rare hepatocytes with an acquired resistance to the mitoinhibitory effect of 2-acetyl-aminofluorene (2-AAF). Two different initiating protocols were used: a feeding regimen during which FB1 was fed at a dietary level of 0.1% for 26 days, and another where single or multiple doses of FB1 and FB2 (varying from 200 to 50 mg/kg) were administered (by gavage) to hepatectomized rats. In both cases promotion was effected by a 2-acetylamino-fluorene/carbontetrachloride treatment. Cancer initiation was only obtained after the prolonged feeding regimen, indicating that the fumonisins are poor cancer initiators. FB1 and FB2 also lack genotoxic effects in the in vivo and in vitro DNA repair assays in primary hepatocytes. Although FB1 primarily affects the liver, it is not very cytotoxic to primary hepatocytes when compared to aflatoxin B1.
Collapse
Affiliation(s)
- W C Gelderblom
- Research Institute for Nutritional Diseases, Tygerberg, Republic of South Africa
| | | | | | | |
Collapse
|
38
|
Abstract
Male F-344 rats were fed a choline-free (CF) diet, and changes in phospholipid content, phospholipid fatty acids and phospholipase A2 activity in liver nuclei and microsomes were examined during the first 72 hr. Both nuclei and microsomes showed a decrease in phosphatidylcholine (PC) content. Microsomes showed an increase in PC arachidonate while nuclei showed a decrease. Also, microsomes showed increased activity of phospholipase A2 (PLA2) while nuclei did not. These observations are consistent with the hypothesis that the absence of diene conjugates in liver microsomes in the rats on the CF diet may reflect the increased rate of removal of peroxidized fatty acids by phospholipase A2.
Collapse
Affiliation(s)
- R Kapoor
- Department of Pathology, University of Toronto, Ontario, Canada
| | | | | |
Collapse
|
39
|
Farber E. Clonal adaptation as an important phase of hepatocarcinogenesis. Cancer Biochem Biophys 1991; 12:157-65. [PMID: 1844908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- E Farber
- Department of Pathology, University of Toronto, Ontario, Canada
| |
Collapse
|
40
|
Abstract
Cell proliferation is the most central and key phenotypic property of cancer including hepatocellular carcinoma. Hepatocyte proliferation is central not only at the late steps in carcinogenesis, the cancer, but at the earliest known step, initiation. Compensatory or regenerative hepatocyte proliferation is essential to initiation with chemical carcinogens but primary hyperplasia is ineffective. During promotion, hepatocyte proliferation is the major change seen as clonal proliferation to generate nodules occurs. During progression, autonomous hepatocyte proliferation balanced by cell loss makes its appearance. This continues in a balanced fashion with only a slight excess of proliferation over loss until the earlier steps in malignancy at which time the balance is disrupted.
Collapse
Affiliation(s)
- E Farber
- Department of Pathology, University of Toronto, Ontario, Canada
| |
Collapse
|
41
|
Farber E, Rubin H. Cellular adaptation in the origin and development of cancer. Cancer Res 1991; 51:2751-61. [PMID: 2032214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- E Farber
- Department of Pathology, University of Toronto, Ontario, Canada
| | | |
Collapse
|
42
|
Golosovsky M, Davidov D, Farber E, Tsach T, Schieber M. Microwave transmission and harmonic generation in granular high-Tc superconducting films: Evidence for viscous flux motion and weak links. Phys Rev B Condens Matter 1991; 43:10390-10398. [PMID: 9996760 DOI: 10.1103/physrevb.43.10390] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
43
|
Kanduc D, Rossiello MR, Aresta A, Cavazza C, Quagliariello E, Farber E. Transitory DNA hypomethylation during liver cell proliferation induced by a single dose of lead nitrate. Arch Biochem Biophys 1991; 286:212-6. [PMID: 1897949 DOI: 10.1016/0003-9861(91)90030-m] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
In the present study we have examined the effect of a single dose of the mitogen lead nitrate (75 mumols/kg body wt) on the methylation status of hepatic DNA in male Wistar rats. It was found that extensive hypomethylation of hepatic DNA occurs in mitogen-treated rat liver. This effect could be seen as early as 12 h after metal treatment and parallels the changes in liver weight. Probing with the methylation-sensitive enzymes HpaII, MspI, and HaeIII confirmed HPLC analyses and showed that methylation at these sites was affected by lead treatment. DNA hypomethylation has already been found in regenerating rat liver and in hepatic (pre)malignant lesions when compared to normal nondividing liver. Thus the lowering of the DNA 5-methylcytosine content appears to be a property characteristic of cellular proliferation, regardless of whether it is caused by partial hepatectomy, carcinogen treatments, or mitogen administration.
Collapse
Affiliation(s)
- D Kanduc
- Department of Biochemistry and Molecular Biology, Faculty of Science, University of Bari, Italy
| | | | | | | | | | | |
Collapse
|
44
|
Wollenberg GK, LaMarre J, Semple E, Farber E, Gauldie J, Hayes MA. Counteracting effects of dexamethasone and alpha 2-macroglobulin on inhibition of proliferation of normal and neoplastic rat hepatocytes by transforming growth factors-beta type 1 and type 2. Int J Cancer 1991; 47:311-6. [PMID: 1703130 DOI: 10.1002/ijc.2910470223] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Primary cultures of hepatocytes isolated from normal F-344 rats or from F-344 rats with hepatocellular carcinomas generated by a 2-step model of chemical carcinogenesis were used to determine if dexamethasone (DEX) or alpha 2-macroglobulin (alpha 2M) modify the ability of transforming growth factors-beta type I (TGF-beta I) and type 2 (TGF-beta 2) to inhibit labelling index of hepatocytes cultured continuously with or without epidermal growth factor (EGF). Both TGF-beta 1 and beta 2 were equivalently potent inhibitors of S-phase DNA synthesis in normal and neoplastic hepatocytes as determined by 3H-thymidine autoradiography. Both DEX (1 to 100 microM) and alpha 2M (50-200 microM) partially counteracted the mito-inhibitory effect of both TGF-betas on the proliferation of normal and surrounding hepatocytes. In contrast, neoplastic hepatocytes cultured with DEX released much less immunoreactive alpha 2M and were less able to overcome the inhibitory effect of TGF-beta than normal or surrounding hepatocytes. Purified bovine alpha 2M partially counteracted the inhibition of TGF-beta 1 or beta 2 of both surrounding and neoplastic hepatocytes. Both DEX and alpha 2M were more effective against the mito-inhibitory activity of TGF-beta 2. Our data suggest that alpha 2M released by DEX-treated normal hepatocytes contributes to the counteraction of the TGF-beta effect by DEX. Our results support the hypothesis that glucocorticoids and growth-factor-binding proteins may have important roles in modulating the effects of TGF-beta on normal hepatocyte proliferation and suggest that under some conditions hepatocellular neoplasms can be more sensitive than normal hepatocytes to inhibition of proliferation by TGF-beta.
Collapse
Affiliation(s)
- G K Wollenberg
- Department of Pathology, University of Guelph, Ontario, Canada
| | | | | | | | | | | |
Collapse
|
45
|
Quinn BA, Crane TL, Kocal TE, Best SJ, Cameron RG, Rushmore TH, Farber E, Hayes MA. Protective activity of different hepatic cytosolic glutathione S-transferases against DNA-binding metabolites of aflatoxin B1. Toxicol Appl Pharmacol 1990; 105:351-63. [PMID: 2173169 DOI: 10.1016/0041-008x(90)90139-l] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
To evaluate the role of glutathione S-transferase (GST) isoenzymes in induced resistance of hepatocytes to aflatoxin B1 (AFB1), we compared DNA protective activities of different hepatic cytosol preparations and purified GSTs from normal rats, rats exposed to different polychlorinated biphenyls (PCBs), and rats with carcinogen-induced hepatocellular neoplasms, with cytosols or purified GSTs from mouse, rainbow trout, and human livers. These comparisons were performed in an in vitro assay for [3H]AFB1-DNA binding after activation by rat liver microsomes. Cytosol and S-hexylglutathione-affinity-purified GST preparations from livers of mice consistently had strong protective activity against AFB1-DNA binding. The majority of this activity was dependent on the presence of reduced glutathione (GSH) but some GSH-independent protection was observed in mouse hepatic cytosol, but not in purified GST preparations. We found that all of the GSH-dependent DNA-protective activity in mouse liver eluted as a single GST isoenzyme by hydroxyapatite chromatography. Preparations of cytosol and purified GSTs from normal rat liver, rainbow trout liver, and human liver had much less AFB1-specific DNA protective activity than GSTs found in mouse liver preparations. Cytosol from rats with carcinogen-generated liver neoplasms and livers induced with 3,3',4,4'-tetrachlorobiphenyl and 2,2',4,4',5,5'-hexachlorobiphenyl had more GST activity toward CDNB than cytosol from normal rat liver. When equivalent units of GST activity (CDNB) were compared, there was little difference observed between the DNA-protective activities of PCB-induced and normal rat liver cytosols, yet cytosol from rat liver neoplasms was more protective. Purified GST-P (7-7), the GST isoenzyme most induced in carcinogen-generated rat liver neoplasms, was not protective when added at protein concentrations found to be protective for total GSTs isolated from these neoplasms. These studies demonstrate that the resistance of mouse liver to AFB1 can be explained primarily by a single constitutive GST isoenzyme (YaYa or 4-4) with a relatively high activity toward DNA-binding metabolites of AFB1. GST isoenzymes with such high specific DNA protective activity against AFB1 metabolites were not evident in human, rat, or rainbow trout liver or in PCB-induced or neoplastic rat liver preparations.
Collapse
Affiliation(s)
- B A Quinn
- Department of Pathology, University of Guelph, Ontario, Canada
| | | | | | | | | | | | | | | |
Collapse
|
46
|
Affiliation(s)
- E Farber
- Department of Pathology, University of Toronto, Ontario, Canada
| |
Collapse
|
47
|
Abstract
This study was designed to explore the possible preventive effects of a novel radicophile, N-p-methoxyphenylacetyl-dehydroalanine (AD5) and three other antioxidants, N,N'-diphenyl-p-phenylenediamine (DPPD), butylated hydroxyanisole (BHA) and a water-soluble analogue of vitamin E, trolox C, on the acute effects of the liver of feeding a choline-deficient (CD) diet. It has been suggested that some of the acute effects of a CD diet are related to free radicals, the generation or metabolism of which is disturbed in this acute dietary model. AD5 was found to be very effective in preventing nuclear lipid peroxidation, DNA damage and cell death induced by a CD diet but to have little effect on triglyceride accumulation ("fatty liver"). DPPD, BHA, and trolox C were ineffective. These results add strength to the hypothesis that oxygen free radicals might be an important component in the early events during carcinogenesis induced by feeding a CD diet.
Collapse
Affiliation(s)
- A K Ghoshal
- Department of Pathology, University of Toronto, Ontario, Canada
| | | | | | | | | |
Collapse
|
48
|
Harris L, Morris LE, Farber E. Protective value of a liver initiation-promotion regimen against the lethal effect of carbon tetrachloride in rats. J Transl Med 1989; 61:467-70. [PMID: 2796292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
This study was designed as one test of the hypothesis that an early sequence of steps in hepatocarcinogenesis in the rat, with the production of hepatocyte nodules, may be a special form of adaptive response that has survival value for the host. Fischer 344 rats were initiated with a single dose of diethylnitrosamine. Hepatocyte nodules were rapidly generated by selecting for resistant hepatocytes by a brief exposure to 2-acetylaminofluorene coupled with partial hepatectomy, a procedure that leads to liver cancer without any further treatment. Most animals with hepatocyte nodules were completely resistant to single doses of CCl4 that induced 100% mortality in control animals. The demonstration of this protective effect is consistent with the proposed hypothesis.
Collapse
Affiliation(s)
- L Harris
- Department of Pathology, University of Toronto, Ontario, Canada
| | | | | |
Collapse
|
49
|
Mohammad F, Farber E. In situ detection of DNA-binding proteins in herpes simplex virus type 1-infected cells. Acta Virol 1989; 33:401-9. [PMID: 2576580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
An in situ assay for detecting DNA-binding proteins in herpes simplex virus type 1 (HSV-1)-infected cells is described. Seventeen HSV-induced DNA-binding species were visible with nicked, double-stranded DNA as a substrate, while fourteen virus-induced DNA-binding fractions were present in gels containing nuclease-treated, single-stranded DNA. The effects of HSV on cellular DNA-binding protein expression could also be seen. The resolution of DNA-binding fractions was dependent upon the type of DNA substrate utilized, high salt extraction of DNA-binding components and their physical separation from infected cell DNAs, dialysis of the high salt and the length of DNase treatment of gels following electrophoresis.
Collapse
Affiliation(s)
- F Mohammad
- Department of Microbiology, University of New Hampshire, Durham 03824
| | | |
Collapse
|
50
|
Eriksson LC, Rinaudo JA, Farber E. Kinetics of interaction of 2-acetylaminofluorene with normal liver and carcinogen-induced hepatocyte nodules in vivo and in vitro. J Transl Med 1989; 60:409-17. [PMID: 2927080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
This study examines the initial uptake and subcellular distribution of the carcinogen [14C]-2-acetylaminofluorene in liver nodules and normal liver. The route of administration of the carcinogen was intravenously through a peripheral branch of the superior mesenteric vein, intragastrically or intraperitoneally. Tissue distribution was initially dependent on blood flow, but the retention after 5 minutes varied between different tissues according to tissue affinity, high in liver, fat and muscle, low in kidney and brain. The major fraction was retained in the liver. In vitro experiments demonstrated that total levels of [14C]-2-acetylaminofluorene were 8-fold lower in hepatocytes from liver nodules compared with normal liver. The 2-acetylaminofluorene was bound more avidly to 12 to 15 kilodalton cytosolic proteins than to 40 to 50 kilodalton proteins in normal liver and this binding was much less in hepatocyte nodules. The subcellular distribution indicated that the microsomal fractions had a greater specificity than mitochondria, homogenate, or cytosol. This specificity was not due to the lipid content of the fractions. Microsomal fractions from liver nodules had 2-fold less [14C]-2-acetylaminofluorene bound than from normal liver. The carcinogen was bound in cytosolic proteins with a peak 90 minutes after intravenous injection, as compared with a peak for microsomes at 10 minutes. These results lend further support for the concept that the biochemical properties in liver nodules minimize the metabolism of xenobiotics in vivo.
Collapse
Affiliation(s)
- L C Eriksson
- Department of Pathology, Karolinska Institutet, Huddinge University Hospital, Sweden
| | | | | |
Collapse
|