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Metabolic Utilization (metabolic + utilization)
Selected AbstractsNitrogen retention as an indicator of metabolic utilization of nitrogen in three months old ostrich chicks (Struthio camelus massaicus)AFRICAN JOURNAL OF ECOLOGY, Issue 4 2002C. O. Orenge No abstract is available for this article. [source] Inhibition of Alcohol-Associated Colonic Hyperregeneration by ,-Tocopherol in the RatALCOHOLISM, Issue 1 2003P. Vincon Background: Chronic alcohol consumption results in colorectal mucosal hyperregeneration, a condition associated with an increased risk for colorectal cancer. Possible mechanisms may involve the effects of acetaldehyde and/or free radicals generated during alcohol metabolism. Vitamin E is part of the antioxidative defense system, and its concentration is decreased or its metabolic utilization increased in various tissues after chronic alcohol consumption. We wondered whether ,-tocopherol supplementation may prevent ethanol-induced colorectal cell cycle behavior and whether these changes were related to alterations in protein synthesis. Methods: Five groups of male Wistar rats, each consisting of 14 animals, received liquid diets as follows: group 1, alcohol; group 2, alcohol +,-tocopherol; group 3, control (i.e., isocaloric glucose); group 4; control (i.e., isocaloric glucose) +,-tocopherol. Group 5 was fed a solid chow diet ad libitum. After 4 weeks of feeding, immunohistology was performed with anti-proliferating cell nuclear antigen (PCNA) or anti-BCL2 antibodies. Fractional (ks) and absolute (Vs) rates of protein synthesis and rates of protein synthesis relative to RNA (kRNA) and DNA (kDNA) were measured with a flooding dose of L-[4- 3H] phenylalanine with complementary analysis of protein and nucleic acid composition. Results: The PCNA index was increased significantly in the colon after ethanol administration compared with controls (ethanol, 10.3 ± 2.3 vs. control, 6.51 ± 1.6% PCNA positive cells, p < 0.05), although neither the protein, RNA, and DNA concentrations nor ks, kRNA, kDNA, and Vs were affected. This increase in PCNA index was significantly diminished by coadministration of ,-tocopherol (ethanol +, - tocopherol, 7.86 ± 1.71% PCNA positive cells, p < 0.05) without significant alterations in protein synthetic parameters. A similar result was obtained for the PCNA index in the rectal mucosa (ethanol, 14.6 ± 4.4 vs. control, 12.1 ± 4.2% PCNA positive cell), although this did not reach statistical significance. Neither ethanol nor , - tocopherol feeding had any significant effect on BCL-2 expression in the colorectal mucosa. As with the colon, protein synthetic parameters in the mucosa were not affected by alcohol feeding at 4 weeks. These effects on colonic cell turnover without corresponding changes in protein synthesis thus represent a specific localized phenomenon rather than a general increase in anabolic processes in the tissue and reaffirm the hyperregenerative properties of chronic alcohol consumption. Conclusions: Alcohol-associated hyperproliferation could be prevented, at least in part, by supplementation with ,-tocopherol. This may support the hypothesis that free radicals are involved in the pathogenesis of alcohol-associated colorectal hyperproliferation. [source] Prospects for the use of differentiation-modulating agents as adjuvant of photodynamic therapy for proliferative dermatosesTHE JOURNAL OF DERMATOLOGY, Issue 4 2008Oleg E. AKILOV ABSTRACT Current interest in photodynamic therapy (PDT) in dermatology stems from its recognized success in dermatological oncology, straightforward approach, easy accessibility and low cost. PDT is a photochemistry-based modality in which a light-activated photosensitizer (PS) destroys tissue through oxygen-dependent and -independent mechanisms. Although PDT has been used in dermatology for several decades, its application has still not extended significantly into the routine management of neoplastic and proliferative dermatoses because of continuing issues with the selectivity of the PS for affected tissues. This review analyzes prospects for optimization of PDT for the management of dermatoses with defects in keratinocyte proliferation/differentiation, and discusses the use of differentiating agents that redirect metabolic utilization within cells and lead to high levels of PS accumulation. [source] Growth performance and metabolic utilization of diets with different protein:carbohydrate ratios by white sea bream (Diplodus sargus, L.) juvenilesAQUACULTURE RESEARCH, Issue 1 2007R Sá First page of article [source] | ||||||||||