The Chalones

Iversen, Olav Hilmar

doi:10.1007/978-3-642-67986-5_17

Cited by 34 publications

(14 citation statements)

References 201 publications

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“…The maximum depression was achieved when the extract was given 2 h before the isotope, which is in accord with the findings of Rytomaa and Kiviniemi [1968] who showed that 3H-TdR incorporation into DNA is evanescent, peaking at 2 h in short term assay. It also supports other evidence that chalones are short lived [Iversen, 1976].…”

Section: Discussionsupporting

confidence: 77%

Granulocyte Chalone Assayed <i>in vivo </i>in the Mouse

Perrins¹,

Wiernik²,

Jones³

1980

Acta Haematol

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An in vivo system has been developed for estimating the inhibitory activities of granulocyte chalone which overcomes the objection to the use of mixed proliferating target cells. It depends on the identification of labelled mature granulocytes in the peripheral blood of mice that received a radioactive precursor of DNA synthesis, with and without granulocyte extracts, several days previously. Two extracts of bovine granulocytes were tested. The first demonstrated that maximum inhibition was achieved when it was given 2 h before the isotope, suggesting that its activity was short lived. It also failed to depress the labelling index of peripheral lymphocytes, thereby demonstrating tissue specificity. The second was used to show that the dose-response relationship was exponential.

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Section: Discussionsupporting

confidence: 77%

Granulocyte Chalone Assayed <i>in vivo </i>in the Mouse

Perrins¹,

Wiernik²,

Jones³

1980

Acta Haematol

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“…Most studies that have been conducted with chemicals known to cause promotion of carcinogenesis have concentrated on the tumorpromoting ability without evaluating other toxic effects. Normal adult differentiated tissues produce specific inhibitors of proliferation, the so-called chalones (Iverson, 1981). Van Potter (1983) has suggested that promoters of liver tumors may diminish the ability of normal adult hepatocytes to inhibit the growth of initiated cells.…”

Section: Discussionmentioning

confidence: 99%

Stunted growth, increased mortality, and liver tumors in offspring of polybrominated biphenyl (PBB) dosed Sherman rats

Groce

Kimbrough

1984

Journal of Toxicology and Environmental Health

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Firemaster FF-1, a polybrominated biphenyl (PBB) mixture, was dissolved in corn oil and given as a dose of 200 mg/kg body weight to Sherman rats on d 7 and 14 of pregnancy. Control rats received equivalent doses of corn oil alone. Selected pups and all dams were killed 1 mo after pups were weaned. A total of 50 male and 50 female offspring per group were followed until they were 2 yr old. The livers of offspring killed at the ages of 2 mo and 2 yr had PBB levels of 2,4 (SD 1.2) and 0.8 (SD 0.65) mg/kg for females and 3.0 (SD 1.6) and 0.6 (SD 0.37) mg/kg for males, respectively. The incidence of hepatocellular carcinomas was 3/51 (5.9%) and 4/41 (9.6%) after 2 yr in females and males, respectively. Hepatocellular carcinomas were not observed among the controls. Neoplastic (hyperplastic) nodules of the liver were present in 9/51 (17.6%) and 2/41 (4.9%) of exposed females and males, respectively, whereas only 2/48 (4.2%) of control females and no control males had neoplastic (hyperplastic) nodules. Body weights were lower in PBB-exposed rats at ages 1, 6, 12, and 24 mo. Survival rates from birth to weaning were lower in PBB-exposed pups (89%) than in controls (98%). Mortality was two times higher in PBB-exposed males (64%) than in control males (32%) after 2 yr. Transplacental PBB exposure and exposure through milk resulted in PBB body burdens in the offspring still measurable at the end of their lifespan. These offspring had increased mortality rates and lower body weights than controls, and they developed hepatocellular carcinomas.

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“…The control of the cell population in epidermis was extensively investigated with much attention to the role of locally acting cell growth inhibitors known as 'chalones' (6). Following the introduction of radioactive DNA precursor techniques, an extensive literature appeared in which the dynamics of the epidermis was investigated, including the concept of 'epidermal proliferative units' (7).…”

Section: Cell Loss From Normal Tissuesmentioning

confidence: 99%

The Case Against Apoptosis

Steel

2001

Acta Oncologica

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Apoptosis is not as dominant a process in cell loss from normal tissues and tumours as has sometimes been claimed. The term 'programmed cell death', which many authors regard as synonymous with apoptosis, is an unsatisfactory term that is best avoided. In studies on the response of tumours to drug and radiation treatment, the use of apoptosis assays concentrates attention on the first decade of cell killing (0-90%), whereas the outcome of treatment depends on multi-log cell kill; an assay of clonogenic cell survival is the appropriate method for this purpose. Loss of colony-forming ability is the key event in treated tumour cells, and the appearance of morphological and molecular evidence of apoptosis is probably downstream from this event. Published studies that have compared apoptosis and cell survival responses in tumour cells have generally failed to find a causal relationship.

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The Chalones

Cited by 34 publications

References 201 publications

Granulocyte Chalone Assayed <i>in vivo </i>in the Mouse

Granulocyte Chalone Assayed <i>in vivo </i>in the Mouse

Stunted growth, increased mortality, and liver tumors in offspring of polybrominated biphenyl (PBB) dosed Sherman rats

The Case Against Apoptosis

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