Publications by authors named "Lyndon L. Larcom"

Concern has been expressed about the fact that cows' milk contains estrogens and could stimulate the growth of hormone-sensitive tumors. In this study, organic cows' milk and two commercial substitutes were digested in vitro and tested for their effects on the growth of cultures of prostate and breast cancer cells. Cows' milk stimulated the growth of LNCaP prostate cancer cells in each of 14 separate experiments, producing an average increase in growth rate of over 30%.

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To delineate the complexity of the response of cells to nanoparticles we have performed a study on HT-29 human colon carcinoma cells exposed first to a fullerene derivative C(60)(OH)(20) and then to physiological copper ions. Our cell viability, proliferation, and intracellular reactive oxygen species (ROS) production assays clearly indicated that C(60)(OH)(20) suppressed cell damage as well as ROS production induced by copper, probably through neutralization of the metal ions by C(60)(OH)(20) in the extracellular space, as well as by adsorption and uptake of the nanoparticles surface-modified by the biomolecular species in the cell medium. This double-exposure study provides new data on the effects of nanoparticles on cell metabolism and may aid the treatment of oxidant-mediated diseases using nanomedicine.

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Berries and berry extracts possess properties that make them important in the prevention of cancer. The high antioxidant levels of these extracts play a role, but components of the berries can have other effects on cell replication and survival. We chose to test the hypothesis that (i) although the antioxidant capacity of raspberry extracts is important for inhibiting the proliferation of tumor cells, other characteristics of the berry extracts are responsible for a major part of their antiproliferative activity, and that (ii) the relative importance of the antioxidant effect can depend on the cell type being studied.

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The initiating event in carcinogenesis is a somatic mutation. During progression of the disease, additional mutations accumulate as the transformed cells develop the ability to proliferate and metastasize. These mutations can be produced by reactive oxygen species (ROS) generated through metabolism, or environmental insult.

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Density gradient centrifugation is a high-resolution technique for the separation and characterization of large molecules and stable complexes. We have analyzed various nanotube structures by preparative centrifugation in sodium metatungstate-water solutions. Bundled, isolated and acid-treated single-walled nanotubes (SWNTs) and multiwall nanotubes (MWNTs) formed sharp bands at well-defined densities.

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The increase in reproductive cancers and developmental problems over the past 70 years has led researchers to suspect environmental influences as a root cause. Evidence from wildlife and laboratory studies suggests that exposure to endocrine disruptors (EnDs) may be the cause. An EnD is a foreign substance or mixture that alters the function of the endocrine system.

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Plants are proven sources of useful anti-tumor and chemopreventative compounds. Hence, identification of phytochemicals useful in dietary prevention and intervention of cancer is of paramount importance. The initial step in the formation of cancer is damage to the genome of a somatic cell producing a mutation in an oncogene or a tumor-suppressor gene.

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While the metalloproteinase enzymes are essential for development and remodeling of tissues, aberrant over expression of these enzymes contributes to several pathologic conditions. In particular, metalloproteinase over expression in cancer plays a significant role in metastasis by providing a mechanism for invasion and spread. The data presented here indicate that water extracts of raspberries, blackberries and muscadine grapes inhibit the activities of metalloproteinases 2 and 9.

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Freeze-dried fruits of two strawberry cultivars, Sweet Charlie and Carlsbad, and two blueberry cultivars, Tifblue and Premier were sequentially extracted with hexane, 50% hexane/ethyl acetate, ethyl acetate, ethanol, and 70% acetone/water at ambient temperature. Each extract was tested separately for in vitro anticancer activity on cervical and breast cancer cell lines. Ethanol extracts from all four fruits strongly inhibited CaSki and SiHa cervical cancer cell lines and MCF-7 and T47-D breast cancer cell lines.

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