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Biomedical subjects

J Carl Barrett

Publications and source records attributed to J Carl Barrett.

112 records · Page 7Linked to original sources
PubMed2001

Calorie restriction, aging, and cancer prevention: mechanisms of action and applicability to humans.

Calorie restriction (CR) is the most effective and reproducible intervention for increasing lifespan in a variety of animal species, including mammals. CR is also the most potent, broadly acting cancer-prevention regimen in experimental carcinogenesis models. Translation of the knowledge gained from CR research to human chronic disease prevention and the promotion of healthy aging is critical, especially because obesity, which is an important risk factor for several chronic diseases, including many cancers, is alarmingly increasing in the Western world. This review synthesizes the key biological mechanisms underlying many of the beneficial effects of CR, with a particular focus on the insulin-like growth factor-1 pathway. We also describe some of the opportunities now available for investigations, including gene expression profiling studies, the development of pharmacological mimetics of CR, and the integration of CR regimens with targeted, mechanism-based interventions. These approaches will facilitate the translation of CR research into strategies for effective human chronic disease prevention.

Aging↗
PubMedDate not supplied

Tumor spectrum in the p53 heterozygous zeta globin-promoted Tg.AC (v-Ha-ras) bitransgenic mouse model.

The use of a bitransgenic mouse model for cancer is an effective approach for studying the impact of specific carcinogens and the occurrence of tissue-specific lesions. We studied the novel p53 heterozygous zeta globin-promoted Tg.AC (v-Ha-ras) mouse model because these mice contain a carcinogen-inducible ras oncogene and one functional p53 tumor suppressor allele, both of which occur frequently in human cancers. Our aim was to characterize the short-term control and chemically induced tumor spectrum in this novel model. Mice were placed on basal semipurified diet containing 20% soy protein for 2 weeks prior to random allocation to groups. Subsequently, 15 male and 15 female mice were administered corn oil vehicle alone or containing benzo(a)pyrene (20 mg/kg body weight) via oral gavage 2 times per week for 10 weeks with subsequent observation for 18 weeks. Mice exhibited lesions characteristic of FVB/N, p53 heterozygous and Tg.AC mouse models. However, an array of unique, novel lesions were observed including uterine leiomyosarcomas, mammary gland carcinomas, mammary squamous cell carcinomas, and parotid salivary gland carcinomas suggesting tissue-specific interactions of the 2 genotypes. Thus, this bitransgenic model may provide further insight into the mechanistic interaction of 2 genes commonly mutated in neoplasia.

Alleles↗
PubMedDate not supplied

Phenotypic effects of calorie restriction and insulin-like growth factor-1 treatment on body composition and bone mineral density of C57BL/6 mice: implications for cancer prevention.

BACKGROUND: Calorie restriction (CR) inhibits carcinogenesis and delays aging. Some anti-carcinogenic effects of CR are mediated by decreased circulating insulin-like growth factor-1 (IGF-1); however, IGF-1 also plays an important role in regulating growth and bone density. MATERIALS AND METHODS: We quantified tradeoffs involving the CR/IGF-1 axis in C57BL/6 mice by examining body composition and bone characteristics in ad libitum fed, 20, 30 or 40% CR mice that received placebo or recombinant murine IGF-1 delivered with a time-release pellet. After 26 days, carcasses were scanned with a PIXImus II dual-energy X-ray absorptiometer. RESULTS: CR reduced body weight and percent body fat and had non-linear effects on bone density. IGF-1 restored bone density to control levels or greater in the CR mice. CONCLUSION: Cancer prevention efforts based on CR and down-regulation of the IGF-1 pathway will require consideration of deleterious effects on bone.

Absorptiometry, Photon↗