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Lester Packer

Publications and source records attributed to Lester Packer.

40 records · Page 3Linked to original sources
PubMed2002

Egb 761 in the postgenomic era: new tools from molecular biology for the study of complex products such as Ginkgo biloba extract.

The decoding of the human genome has completely changed our views on medicine. Beyond sequencing, tools of the postgenomic era may lead to a better understanding of various therapies, especially those with a complex effect on numerous cellular components and functions. The development of high-density oligonucleotide microarrays led to pioneer studies on the multiple gene expression effects exhibited by Ginkgo biloba extract EGb 761, changing traditional pharmacology and medicine concepts. Instead of studying a simple gene or protein, a global investigation of all genes or proteins at once can give insights of the complexity of biological systems.

Gene Expression Regulation↗
PubMed2002

Global gene expression analysis identifies cell and tissue specific actions of Ginkgo biloba extract, EGb 761.

Clinical and pre-clinical uses of Ginkgo biloba extract encompass a broad spectrum of pathologies that include peripheral arterial disorders, cardiovascular and neuronal dysfunctions and resolution of ischemia-reperfusion injuries. Many of these pathologies develop over time and recruit multiple cell types and molecular pathways that alter the cellular a nd molecular profiles of the failing targetorgans. Transcriptional processes are important determinants of the pathogenesis of these chronic disease states. Therefore the potential therapeutic and preventive actions of a standardized Ginkgo biloba extract, EGb 761, may be affected through modulation of transcriptional processes. We have used various techniques for large-scale mRNA expression analysis, including differential display of mRNAs, cDNA arrays and high-density oligonucleotide arrays, to evaluate the actions of EGb 761 on the activities of the genomes in vitro and in vivo. The results show broad but cell specific actions of Ginkgo biloba extract that may enhance antioxidant defenses in vitro in cancer cells and modulate neuronal functions in cortex and hippocampus in brain in vivo. The large scale analysis of mRNAs in response to Ginkgo biloba extract in vitro and in vivo show that the standardized extract affects the activities of the mammalian genome. The data provide some support for the concept that the actions of EGb 761 are mediated through it effects on the process of gene transcription which plays a causative role in chronic diseases.

Animals↗
PubMedDate not supplied

Antioxidants and the response of skin to oxidative stress: vitamin E as a key indicator.

As the outermost barrier of the body, the skin is directly and frequently exposed to a prooxidative environment, including solar UVA and UVB radiation, and air pollution. The skin is equipped with an elaborate system of antioxidant substances and enzymes that includes a network of redox active antioxidants. Among these, vitamin E has been identified as the predominant antioxidant both in murine and human skin and shows a characteristic gradient with lower levels towards the outer stratum corneum layers. Skin exposure to UV and ozone alone and in combination resulted in a significant potentiation of the UV-induced vitamin E depletion. Oxidants and antioxidants play an important role in maintaining a balance between free radicals produced by metabolism or derived from environmental sources. Cellular antioxidants may change their redox state, be targeted for destruction, regulate oxidative process involved in signal transduction, affect gene expression and pathways of cell proliferation and death. Here we provide an overview of the antioxidant system with a special relevance to skin.

Animals↗