76
|
Kerry PJ, Evans JG, Pearson EC, Coleman H. Identification of a spontaneous pleomorphic rhabdomyosarcoma in the thoracic and abdominal cavities of a female Wistar rat. Vet Pathol 1995; 32:76-8. [PMID: 7725603 DOI: 10.1177/030098589503200114] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
|
77
|
Pedrick MS, Rumsby PC, Wright V, Phillimore HE, Butler WH, Evans JG. Growth characteristics and Ha-ras mutations of cell cultures isolated from chemically induced mouse liver tumours. Carcinogenesis 1994; 15:1847-52. [PMID: 7522981 DOI: 10.1093/carcin/15.9.1847] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Cells have been isolated from liver tumours that have arisen in control C3H/He mice, in mice given 10 micrograms diethylnitrosamine (DEN) during the neonatal period or in mice given a diet containing phenobarbitone (PB) to allow a daily intake of 85 mg/kg/day. The cells were grown to the 8 degrees subculture when their growth characteristics were investigated in monolayer culture and following suspension in soft agar and on transplantation into nude mice. In addition, DNA was isolated from the cultures and from tumours that grew in nude mice and analysed for mutations at codon 61 of the Ha-ras oncogene. All cells derived from DEN-induced hepatocellular carcinomas (HCC) demonstrated a lack of density inhibition of growth in monolayer culture, grew in soft agar and formed tumours in nude mice with an average mean latency of 29 days. Three of the seven lines showed mutations in Ha-ras: two were CAA-->AAA transversions and one showed a CAA-->CTA transversion. In contrast, cells isolated from eosinophilic nodules in mice given PB showed inhibition of growth at confluence, did not grow in soft agar and only four of eight formed tumours in nude mice with a mean average latent period of 181 days. Cells grown from HCC in mice given PB showed a lack of density inhibition of growth, however, they did not grow in soft agar nor did they form tumours in nude mice. A single spontaneous HCC from a control mouse showed a similar growth pattern to HCC cells isolated from mice given PB. Cells from a basophilic nodule, taken from a control untreated mouse grew vigorously in culture and in soft agar and formed tumours in nude mice with a latency of 6 days. None of the cells isolated from control mice or from mice given PB showed evidence of mutations at codon 61 of Ha-ras. These data confirm that there are fundamental differences in the biology of cells grown from tumours that develop in mice under different treatment regimes. These studies also demonstrate the utility of cell culture and molecular biology in addressing the fundamental mechanism of mouse hepatic neoplasia.
Collapse
|
78
|
Bulpitt CJ, Fletcher AE, Amery A, Coope J, Evans JG, Lightowlers S, O'Malley K, Palmer A, Potter J, Sever P. The Hypertension in the Very Elderly Trial (HYVET). Rationale, methodology and comparison with previous trials. Drugs Aging 1994; 5:171-83. [PMID: 7803945 DOI: 10.2165/00002512-199405030-00003] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The Hypertension in the Very Elderly Trial (HYVET) is a multicentre, open, randomised, controlled trial. The aim of this trial is to investigate the effect of active treatment on stroke incidence in hypertensive patients over the age of 80 years. Secondary end-points include total cardiovascular mortality and morbidity. Entry criteria include a sustained sitting systolic blood pressure of 160 to 219mm Hg plus a sustained sitting diastolic pressure of 95 to 109mm Hg. Also required is a standing systolic blood pressure of at least 140mm Hg. Patients must give their informed consent, and be free of congestive heart failure requiring treatment, gout, renal failure or a recent cerebral haemorrhage. Patients are to be randomised to 3 groups-(i) no treatment; (ii) treatment with a diuretic [bendroflumethiazide (bendrofluazide)]; or (iii) treatment with an angiotensin converting enzyme (ACE) inhibitor (lisinopril). Starting dosage for bendroflumethiazide and lisinopril is 2.5 mg/day. In order to achieve goal sitting systolic and diastolic blood pressures (< 150/80 mm Hg), a doubling of the dosage is allowed. Furthermore, slow release diltiazem (120 mg/day increasing to 240 mg/day if required) may be added to the medication of the actively treated groups. These drugs have been chosen as inexpensive and appropriate representatives of their therapeutic classes. 700 patients in each group (a total of 2100) will be sufficient to detect a 40% difference in cerebrovascular events between no treatment and active treatment (alpha = 0.01, 1-beta = 0.90). These numbers will also detect a difference in total mortality of 25% and in cardiovascular mortality of 35%. The pilot phase of the trial has been started with support from the British Heart Foundation. Centres which are interested in taking part should contact C.J. Bulpitt or any of the other authors.
Collapse
|
79
|
Evans JG. The art of writing successful research abstracts. Neonatal Netw 1994; 13:49-52. [PMID: 7854262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Successful dissemination of your research requires planning. Your abstract is a succinct presentation of a portion of your research specifically designed to capture the attention of the audience you have chosen. The art of writing a successful abstract involves planning, like any other work of art, and is accomplished in stages. This article provides pointers for dissemination of research, describes the stages involved in writing competitive abstracts, and suggests alternative approaches to writing abstracts.
Collapse
|
80
|
Lake BG, Evans JG, Lewis DF, Price RJ. Comparison of the hepatic effects of coumarin, 3,4-dimethylcoumarin, dihydrocoumarin and 6-methylcoumarin in the rat. Food Chem Toxicol 1994; 32:743-51. [PMID: 8070739 DOI: 10.1016/s0278-6915(09)80007-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The mechanism of coumarin-induced hepatotoxicity in the rat has been investigated by comparing the effects of coumarin with those of three coumarin derivatives, namely 3,4-dihydrocoumarin (DHC), 3,4-dimethylcoumarin (3,4-DMC) and 6-methylcoumarin (6-MC). Male Sprague-Dawley rats were fed either control diet or diets containing 0.5 or 0.75% coumarin, 0.76% DHC, 0.6 or 0.9% 3,4-DMC or 0.82% 6-MC for 13 wk. The dietary levels of 0.5% coumarin and 0.6% 3,4-DMC, were equimolar (3.43 mmol/100 g diet), as were the dietary levels of 0.75% coumarin, 0.76% DHC, 0.9% 3,4-DMC and 0.82% 6-MC (5.14 mmol/100 g diet). All treatments resulted in an increase in relative liver weight, but only coumarin increased plasma alanine aminotransferase and aspartate aminotransferase activities. Morphological examination of liver sections from coumarin treated rats revealed vacuolation of centrilobular hepatocytes and bile duct hyperplasia. Cholangiofibrosis was also observed, particularly in rats given 0.75% coumarin. Treatment with DHC produced no abnormalities, whereas a slight hypertrophy of centrilobular hepatocytes was observed in some 3,4-DMC treated animals and a slight vacuolation of individual hepatocytes was noted in some 6-MC treated rats. DHC, 6-MC and particularly 3,4-DMC treatment resulted in an induction of cytochrome P-450 dependent mixed function oxidase enzyme activities. All treatments induced hepatic GSHS-transferase and gamma-glutamyltransferase activities, induction being most marked in rats given coumarin and 6-MC. These results provide further evidence that coumarin-induced hepatotoxicity in the rat is due to the formation of a 3,4-epoxide intermediate.
Collapse
|
81
|
Bulpitt CJ, Fletcher AE, Amery A, Coope J, Evans JG, Lightowlers S, O'Malley K, Palmer A, Potter J, Sever P. The Hypertension in the Very Elderly Trial (HYVET). J Hum Hypertens 1994; 8:631-2. [PMID: 7990098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
|
82
|
|
83
|
|
84
|
Stähelin HB, Beregi E, Duursma SA, Evans JG, Michel JP, Ruiz-Torres A, Steen B. Teaching medical gerontology in Europe. Group of European Professors in Medical Gerontology (GEPMG). Age Ageing 1994; 23:179-81. [PMID: 8085499 DOI: 10.1093/ageing/23.3.179] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
|
85
|
Lake BG, Evans JG, Lewis DF, Price RJ. Studies on the acute effects of coumarin and some coumarin derivatives in the rat. Food Chem Toxicol 1994; 32:357-63. [PMID: 8206431 DOI: 10.1016/0278-6915(94)90074-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The mechanism of acute coumarin-induced hepatotoxicity in the rat has been investigated by comparing the effects of coumarin with those of a number of methyl-substituted coumarin derivatives. Male Sprague-Dawley rats were given single ip doses of corn oil (control), coumarin (0.86 and 1.71 mmol/kg body weight), 3,4-dimethylcoumarin (3,4-DMC, 1.71 and 2.57 mmol/kg), 3-, 4- and 6-methylcoumarins (3-MC, 4-MC and 6-MC, 1.71 mmol/kg) and 3- and 4-methyloctahydrocoumarins (3-MOHC and 4-MOHC, 2.57 mmol/kg) and hepatotoxicity assessed after 24 hr. Coumarin administration produced dose-related hepatic necrosis and a marked elevation of plasma alanine aminotransferase and aspartate aminotransferase activities. In contrast, none of the coumarin derivatives examined produced either hepatic necrosis or elevated plasma transaminase activities. Treatment with coumarin reduced hepatic microsomal ethylmorphine N-demethylase and 7-ethoxycoumarin O-deethylase activities, whereas one or both mixed-function oxidases appeared to be induced by treatment with 3,4-DMC, 4-MC, 3-MOHC and 4-MOHC. These results provide further evidence that acute coumarin-induced hepatotoxicity in the rat is due to the formation of a coumarin 3,4-epoxide intermediate. That 3- and/or 4-methyl substitution (i.e. 3-MC, 4-MC and 3,4-DMC) leads to a reduction in coumarin-induced hepatotoxicity, due to diminished formation of 3,4-epoxide intermediates, was confirmed by the results of molecular orbital calculations.
Collapse
|
86
|
|
87
|
Rumsby PC, Davies MJ, Evans JG. Screening for p53 mutations in C3H/He mouse liver tumors derived spontaneously or induced with diethylnitrosamine or phenobarbitone. Mol Carcinog 1994; 9:71-5. [PMID: 8142011 DOI: 10.1002/mc.2940090204] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Distinct differences have been described in the development of C3H/He mouse liver tumors induced by the genotoxic carcinogen diethylnitrosamine (DEN) and by the nongenotoxic agent phenobarbitone (PB) in terms of pathology and the frequency of mutation at codon 61 of the Ha-ras oncogene. To further define the mechanisms involved, we screened the tumor suppressor gene p53 for mutations in exons 5, 7, and 8 using polymerase chain reaction (PCR)-single-strand conformation polymorphism (SSCP) analysis. Nearly all the mutations so far described have been found within these three exons. In this study a total of six spontaneous tumors, eight tumors induced by PB, 14 tumors induced by DEN, and five samples of normal liver tissue were screened, and no mutations were found in any of the tumors examined. The positive control, the plasmid LTRp53cG (val), had a point mutation in exon 5 that was detected by PCR-SSCP. Since many of the tumors were late-stage hepatocellular carcinomas, we concluded that mutations in exons 5, 7, and 8 of the p53 gene do not play an important role in the development of chemically induced liver tumors in the C3H/He mouse.
Collapse
|
88
|
Evans JG. The role of the physician in geriatric medicine in the ageing society. In epidemiology. Age Ageing 1994; 23 Suppl 3:S12-4. [PMID: 9233440 DOI: 10.1093/ageing/23.suppl_3.s12] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
|
89
|
Evans JG. High hopes ...for geriatrics. A view from the top. JOURNAL OF THE ROYAL COLLEGE OF PHYSICIANS OF LONDON 1994; 28:392-3. [PMID: 7807422 PMCID: PMC5401013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
|
90
|
Lake BG, Evans JG. Effect of pretreatment with some mixed-function oxidase enzyme inducers on the acute hepatotoxicity of coumarin in the rat. Food Chem Toxicol 1993; 31:963-70. [PMID: 8282280 DOI: 10.1016/0278-6915(93)90005-j] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Male Sprague-Dawley rats were pretreated with saline, corn oil, sodium phenobarbitone (PB) (100 mg/kg body weight/day), 20-methylcholanthrene (20 MC) (20 mg/kg body weight/day) or Aroclor 1254 (ARO) (100 mg/kg body weight/day) by daily ip injections for 5 days. Animals were then given single oral doses of either 250 or 500 mg coumarin/kg body weight and hepatotoxicity was assessed after 24 hr. Coumarin produced hepatotoxicity, which comprised hepatocyte necrosis and elevation of plasma alanine aminotransferase and aspartate aminotransferase activities, in all pretreated groups. Hepatic microsomal cytochrome P-450 levels were reduced after coumarin administration. In rats pretreated with saline, corn oil or PB, coumarin produced centrilobular hepatic necrosis, whereas in rats pretreated with 20 MC or ARO, coumarin produced periportal hepatic necrosis. These results demonstrate that mixed-function oxidase enzyme inducers can modulate acute coumarin-induced hepatotoxicity in the rat. As coumarin is known to be bioactivated by cytochrome P-450-dependent enzymes, the change in the lobular distribution of toxicity after pretreatment with 20 MC or ARO is presumably due to the induction of particular cytochrome P-450 isoenzymes in periportal hepatocytes.
Collapse
|
91
|
Lake BG, Evans JG, Cunninghame ME, Price RJ. Comparison of the hepatic effects of nafenopin and WY-14,643 on peroxisome proliferation and cell replication in the rat and Syrian hamster. ENVIRONMENTAL HEALTH PERSPECTIVES 1993; 101 Suppl 5:241-247. [PMID: 8013414 PMCID: PMC1519442 DOI: 10.1289/ehp.93101s5241] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Male Sprague-Dawley rats were fed control diet or diet containing 0.05% nafenopin (NAF) or 0.025% WY-14,643 (WY) and male Syrian hamsters were fed control diet or diet containing 0.25% NAF or 0.025% WY for periods of 1, 15, 40, and 60 weeks. Both NAF and WY produced a sustained increase in liver weight and induction of peroxisomal fatty acid beta-oxidation in the rat and Syrian hamster. Replicative DNA synthesis was studied by implanting osmotic pumps containing [3H] thymidine during weeks 0-1, 14-15, 39-40, and 59-60. Cell replication, determined either as the hepatocyte labelling index or by incorporation of radioactivity into liver whole homogenate DNA, was increased in rats given NAF and WY for 1 week. However, only WY produced a sustained increased in cell replication after 15-60 weeks. After 40 weeks, liver nodules and tumors were present in WY-treated rats, and these lesions were observed in all WY-treated and some NAF-treated rats after 60 weeks. In contrast to the rat, no marked effect on replicative DNA synthesis and no liver nodules and tumors were observed in Syrian hamsters given NAF and WY for up to 60 weeks. The rat study demonstrates that liver tumors are produced more rapidly by doses of peroxisome proliferators that produce a sustained stimulation of cell replication, whereas the hamster study suggests that species differences may exist in both peroxisome proliferator-induced cell replication and liver tumor formation.
Collapse
|
92
|
Evans JG. Clinical geratology. JOURNAL OF THE ROYAL COLLEGE OF PHYSICIANS OF LONDON 1993; 27:339-40. [PMID: 8377177 PMCID: PMC5396777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
|
93
|
Evans JG. Hypothesis: Healthy Active Life Expectancy (HALE) as an index of effectiveness of health and social services for elderly people. Age Ageing 1993; 22:297-301. [PMID: 8213338 DOI: 10.1093/ageing/22.4.297] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
|
94
|
Winner SJ, Evans JG. Guillain-Barré syndrome in Oxfordshire: clinical features in relation to age. Age Ageing 1993; 22:164-70. [PMID: 8503311 DOI: 10.1093/ageing/22.3.164] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
We have examined the clinical features of Guillain-Barré syndrome (GBS) in a UK series with a valid epidemiological base, studying cases from a geographically-defined population using enhanced data from the Oxford record linkage study and applying standard diagnostic criteria. Clinical features in patients aged > or = 60 years were compared with those aged 20-59 years. Cranial nerve involvement was found less often in old than in young adults (6/21 vs 27/41, chi 2 p < 0.02). Old patients more frequently had other diagnoses accompanying GBS (10/21 vs 3/41, p < 0.001). There were no significant differences between old and young in: occurrence or type of preceding illness; site of symptoms at onset; severity of maximal neurological impairment; sphincter dysfunction or any autonomic involvement; requirement for artificial ventilation; case fatality rate; proportion of patients with no residual disability at or before 12 months from onset; mean duration from onset to maximal neurological impairment, from onset to first signs of recovery, and from maximal neurological impairment to recovery ('plateau time'). The variety and severity of clinical features of Guillain-Barré syndrome are similar in old and young adults.
Collapse
|
95
|
Kerry PJ, Wakefield ID, Evans JG. Ocular changes induced in the beagle dog by intravenous infusion of a novel dopaminergic compound, FPL 65447. Toxicol Pathol 1993; 21:274-82. [PMID: 7902612 DOI: 10.1177/019262339302100302] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
FPL 65447, a selective D1 receptor agonist with a potential for the acute treatment of renal and cardiac failure and of sepsis and septic shock, was administered to beagle dogs by continuous intravenous infusion for a maximum of 14 days. Ophthalmoscopical examination revealed dose-related changes in the eye and associated structures, consisting of foci of retinal discolouration, corneal changes including oedema, keratitis, opacities and neovascularisation, and inflammation of the iris, periorbital tissues, and adnexa. Microscopical examination confirmed the presence of inflammatory lesions in the eye. These were predominantly histiocytic and were mainly focal circumscribed lesions. More diffuse inflammation with a granulocytic and lymphocytic component was also encountered in the limbus and uveal tract. A predominantly interstitial histiocytic adenitis involving various glandular structures associated with the eye and adnexa was also identified. Possible mechanisms to account for the histiocytic changes are discussed.
Collapse
|
96
|
|
97
|
|
98
|
Price RJ, Evans JG, Lake BG. Comparison of the effects of nafenopin on hepatic peroxisome proliferation and replicative DNA synthesis in the rat and Syrian hamster. Food Chem Toxicol 1992; 30:937-44. [PMID: 1473786 DOI: 10.1016/0278-6915(92)90178-n] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Male Sprague-Dawley rats were fed control or 0.1% nafenopin diet and male Syrian hamsters were fed control or 0.25% nafenopin diet for periods of 7 and 54 days. Nafenopin treatment produced a sustained increase in liver weight and induction of hepatic peroxisomal and microsomal fatty acid-oxidizing enzyme activities, with a greater effect being observed in the rat. Replicative DNA synthesis was studied by implanting osmotic pumps containing [3H]thymidine during study days 0-7 and 47-54. Cell replication, determined either as the hepatocyte labelling index or by incorporation of radioactivity into liver whole homogenate DNA, was increased in rats given nafenopin for 7 and 54 days. In contrast to the rat, no significant effect on replicative DNA synthesis was observed in the Syrian hamster. These results provide further evidence for species differences in hepatic peroxisome proliferation, with the Syrian hamster being less responsive than the rat. Furthermore, while peroxisome proliferators produce hyperplasia in rat and mouse liver, these data suggest that they may not have any marked effect on hepatic replicative DNA synthesis in the Syrian hamster.
Collapse
|
99
|
Evans JG, Collins MA, Lake BG, Butler WH. The histology and development of hepatic nodules and carcinoma in C3H/He and C57BL/6 mice following chronic phenobarbitone administration. Toxicol Pathol 1992; 20:585-94. [PMID: 1308624 DOI: 10.1177/019262339202000405] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Male C3H/He and C57BL/6 mice were given diets containing sodium phenobarbitone (PB) to allow a daily intake of 85 mg/kg. Control and treated animals were killed at 5, 30, 40, 60, and 80 wk. Other mice were killed in extremis or at the end of the respective experiments: 91 wk for C3H/He and 100 wk for the C57BL/6 animals. A basophilic nodule was found in 1/5 control C3H/He mice at 30 wk; these nodules increased in number with time so that nodules of this type were found in approximately 70% of animals by 91 wk. Nodules were not found in control C57BL/6 mice until 80 wk, when they were found in 4% of mice. PB treatment markedly increased the number of hepatic nodules in both strains of mice. The additional nodule burden was due to the development of a second nodule type formed of large cells with a predominantly eosinophilic cytoplasm. C3H/He animals given PB for 60 wk and then returned to a control diet bore fewer nodules at 91 wk than treated mice killed at 60 or 91 wk. The cumulative incidence of carcinoma in control C3H/He and C57BL/6 mice was 28 and 4%, respectively. The incidence of carcinoma was not increased by PB treatment in either strain. It is concluded that both strains of mice behave in a qualitively similar way to PB administration, although they show considerable quantitative differences in terms of the time and number of nodules that develop. Furthermore, the increased nodule numbers associated with PB treatment were not accompanied by an increase in the number of carcinomas.
Collapse
|
100
|
Rumsby PC, Evans JG, Phillimore HE, Carthew P, Smith AG. Search for Ha-ras codon 61 mutations in liver tumours caused by hexachlorobenzene and Aroclor 1254 in C57BL/10ScSn mice with iron overload. Carcinogenesis 1992; 13:1917-20. [PMID: 1423854 DOI: 10.1093/carcin/13.10.1917] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
C57BL/10ScSn mice administered iron--dextran and fed the environmental pollutants hexachlorobenzene (HCB) and polychlorinated biphenyls (PCBs) develop hepatic nodules and carcinomas within 18 months. A range of lesions from the livers were analysed for the presence of mutations in the Ha-ras proto-oncogene at codon 61 using the polymerase chain reaction to amplify DNA from formalin-fixed sections, followed by oligonucleotide hybridization. Only two mutations from 23 preneoplastic and neoplastic lesions induced by HCB were detected (a focus of altered cells and a trabecular cell carcinoma). With Aroclor 1254 no mutations were detected in 28 areas at various stages of carcinogenesis analysed. Sequencing of the two mutations generated by HCB showed a C-->T transversion at the first base of codon 61 (carcinoma) and an A-->T transversion at the second base (proliferative focus). Thus, in marked contrast to some other systems of mouse liver tumour induction, hepatocarcinogenesis caused by HCB and PCBs in C57BL/10ScSn mice is an example of carcinogenesis which does not involve a high frequency of Ha-ras gene mutation at codon 61.
Collapse
|