Effect of chronic stress on ENU-induced tumors

Sotelo, Julio; Palencia, Guadalupe; Rosas, Norma; Perez, Rodolfo

doi:10.1016/0006-3223(89)90103-0

Cited by 9 publications

(3 citation statements)

References 20 publications

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“…A number of studies have investigated the possibility of acceleration (promotion) of ENUinduced tumors by known promoters like TPA [Kokunai et al, 1986[Kokunai et al, , 1987, phenobarbital [Walker and Swenberg, 1989], X-irradiation [Kalter et al, 1980], methylazoxymethanol [Kalter et al, 1982], hexachlorophane [Purves and Dayan, 1992] and chronic stress [Sotelo et al, 1989]. With the exception of Kokunai's reports, all investigators reported a lack of promoting effect on the rat brain tumors induced by ENU.…”

Section: Discussionmentioning

confidence: 99%

Evaluation of the potential promoting effect of 60 Hz magnetic fields on N-ethyl-N-nitrosourea induced neurogenic tumors in female F344 rats

Mandeville¹,

Franco²,

Sidrac-Ghali³

et al. 2000

Bioelectromagnetics

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The present study investigated the possible effect of 60 Hz magnetic fields (MFs) as promoters of neurogenic tumors initiated transplacentally by a chemical carcinogen, N-ethyl-N-nitrosourea (ENU). In a preliminary study, 5 mg of ENU was shown to induce 30 to 40% neurogenic tumors in F344 rats offspring after 420 days of observation. In the present study, 400 female rats were divided into eight different groups (50 animals/group) and exposed in utero (on day 18 of gestation) to a single intravenous dose of either Saline (Group I), or ENU, 5 mg/kg (Group II to VIII). Dams in group II were given no further treatment while dams in Groups III to VII were exposed to 5 different intensities of MFs forty eight hours later. Animals in group III were sham exposed (<0.02 microT) while groups IV to VII were exposed to 2, 20, 200, and 2000 microT, respectively. Dams in Group VIII were injected intraperitoneally with 12-O-tetradecanoylphrobol-13-acetate (TPA; 10 micrograms/kg) from day 19 until delivery, and then their female offspring continued to be injected every 15 days, starting at day 14 after birth until sacrifice (positive controls). Accordingly, this study included three different types of controls: Internal controls (Groups II and III) and positive control (Group VIII). Body weight, mortality and clinical observations were evaluated in all groups of animals during in-life exposure. Necropsy was performed on all exposed and control animals that died, were found moribund or sacrificed at termination of the study. Histopathological evaluation was done for all brains, spinal cords, cranial nerves, major organs (lungs, liver, spleen, kidneys, pituitary, thyroid and adrenals) and all gross lesions observed during necropsy. All clinical observations and pathological evaluations were conducted under "blinded" conditions. The findings from this ENU/MFs promotion study clearly demonstrate that, under our defined experimental conditions, exposure to 60 Hz linear (single axis) sinusoidal, continuous wave MFs had no effect on the survival of female F344 rats or on the number of animals bearing neurogenic tumors. These results suggest that MFs have no promoting effect on neurogenic tumors in the female F344 rats exposed transplacentally to ENU.

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Section: Discussionmentioning

confidence: 99%

Evaluation of the potential promoting effect of 60 Hz magnetic fields on N-ethyl-N-nitrosourea induced neurogenic tumors in female F344 rats

Mandeville¹,

Franco²,

Sidrac-Ghali³

et al. 2000

Bioelectromagnetics

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“…ENU was intravenously injected at a single dose of 50 mg/kg of body weight to ten pregnant Wistar rats on the 19th day of gestation (Duckrey et al 1966;Sotelo et al 1989). The progeny were weaned at 6 weeks of age and randomly separated into two groups: controls (n=44) and the ASA treated group (n=43).…”

Section: Induction Of Cns Tumors By Enu and Asa Treatmentmentioning

confidence: 99%

Paradoxical effect of aspirin on the growth of C6 rat glioma and on time of development of ENU-induced tumors of the nervous system

Arrieta

Guevara

Reyes

et al. 2001

J Cancer Res Clin Oncol

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The growth-promoting effects of high doses of ASA found in the present study in both transplanted and chemically-induced brain tumors, might be due to the blockage of autocrine inhibitory factors dependent on the cyclooxygenase pathway or by increased vascular permeability and blood supply to the tumor due to inhibition of platelet aggregation. In contrast, the inhibition of tumor growth obtained with low ASA doses in transplanted glioma might be due to different mechanisms such as the induction of apoptosis.

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“…The effectiveness of the nitrosoureas, particularly MNU (184), which has been associated with enhancement of some forms of cancer, and phenobarbital (185) were not observed to increase the incidence of transplacental ENU-induced brain tumors in rats.…”

Section: Animal Models Ofhuman Leukemiamentioning

confidence: 99%

Testing Electromagnetic Fields for Potential Carcinogenic Activity: A Critical Review of Animal Models

McCann¹,

Kavet²,

Rafferty³

1997

Environmental Health Perspectives

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Effect of chronic stress on ENU-induced tumors

Cited by 9 publications

References 20 publications

Evaluation of the potential promoting effect of 60 Hz magnetic fields on N-ethyl-N-nitrosourea induced neurogenic tumors in female F344 rats

Evaluation of the potential promoting effect of 60 Hz magnetic fields on N-ethyl-N-nitrosourea induced neurogenic tumors in female F344 rats

Paradoxical effect of aspirin on the growth of C6 rat glioma and on time of development of ENU-induced tumors of the nervous system

Testing Electromagnetic Fields for Potential Carcinogenic Activity: A Critical Review of Animal Models

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