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Intermediate Metabolites (intermediate + metabolite)

Distribution by Scientific Domains

Medical Sciences	60%

Selected Abstracts

The role of colonic metabolism in lactose intolerance

EUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 8 2008
T. He
ABSTRACT Lactose maldigestion and intolerance affect a large part of the world population. The underlying factors of lactose intolerance are not fully understood. In this review, the role of colonic metabolism is discussed, i.e. fermentation of lactose by the colonic microbiota, colonic processing of the fermentation metabolites and how these processes would play a role in the pathophysiology of lactose intolerance. We suggest that the balance between the removal and production rate of osmotic,active components (lactose, and intermediate metabolites, e.g. lactate, succinate, etc.) in the colon is a key factor in the development of symptoms. The involvement of the colon may provide the basis for designing new targeted strategies for dietary and clinical management of lactose intolerance. [source]

Cytotoxic effects of ,, T cells expanded ex vivo by a third generation bisphosphonate for cancer immunotherapy

INTERNATIONAL JOURNAL OF CANCER, Issue 1 2005
Kiyoshi Sato
Abstract Nitrogen containing-bisphosphonates (N-BPs), widely used to treat bone diseases, have direct antitumor effects via the inactivation of Ras proteins. In addition to the direct antitumor activities, N-BPs expand gd,,T cells, which exhibit major histocompatibility complex-unrestricted lytic activity. BPs accumulate intermediate metabolites which may be tumor antigens in target cells. The purpose of our study was to clarify the cytotoxicity of gd,, T cells expanded ex vivo by the most potent N-BP, zoledronate (ZOL). Especially, we focused on the importance of pretreatment against target cells also with ZOL; 1 m,M ZOL plus IL-2 increased the absolute number of gd,,T cells 298,768 fold for 14 days incubation. The small cell lung cancer and fibrosarcoma cell lines pretreated with 5 m,M ZOL showed a marked increase in sensitivity to lysis by gd,,T cells. While, untreated cell lines were much less sensitive to lysis by gdT cells. Video microscopy clearly demonstrated that gd,,T cells killed target cells pre-treated with ZOL within 3 hr. Pretreatment with 80 m,g/kg ZOL also significantly enhanced the antitumor activity of gd,,T cells in mice xenografted with SBC-5 cells. These findings show that ZOL significantly stimulated the proliferation of gd,,T cells and that gd,,T cells required pre-treatment with ZOL for cytotoxic activity against target cells. © 2005 Wiley-Liss, Inc. [source]

Methionine gamma-lyase: The unique reaction mechanism, physiological roles, and therapeutic applications against infectious diseases and cancers

IUBMB LIFE, Issue 11 2009
Dan Sato
Abstract Sulfur-containing amino acids (SAAs) are essential components in many biological processes and ubiquitously distributed to all organisms. Both biosynthetic and catabolic pathways of SAAs are heterogeneous among organisms and between developmental stages, and regulated by the environmental changes. Limited lineage of organisms ranging from archaea to plants, but not human, possess a unique enzyme methionine gamma-lyase (MGL, EC 4.4.1.11) to directly degrade SAA to ,-keto acids, ammonia, and volatile thiols. The reaction mechanisms and the physiological roles of this enzyme are partially demonstrated by the enzymological analyzes, structure determination, isotopic labeling of the intermediate metabolites, and functional analyzes of deficient mutants. MGL has been exploited as a drug target for the infectious diseases caused by parasitic protozoa and anaerobic periodontal bacteria. In addition, MGL has been utilized to develop therapeutic interventions of various cancers, by introducing recombinant proteins to deplete methionine essential for the growth of cancer cells. In this review, we discuss the current understanding of enzymological properties, putative physiological roles, and therapeutic applications of MGL. © 2009 IUBMB IUBMB Life, 61(11): 1019,1028, 2009 [source]

Mitochondrial A, A potential cause of metabolic dysfunction in Alzheimer's disease

IUBMB LIFE, Issue 12 2006
Xi Chen
Abstract Deficits in mitochondrial function are a characteristic finding in Alzheimer's disease (AD), though the mechanism remains to be clarified. Recent studies revealed that amyloid , peptide (A,) gains access into mitochondrial matrix, which was much more pronounced in both AD brain and transgenic mutant APP mice than in normal controls. A, progressively accumulates in mitochondria and mediates mitochondrial toxicity. Interaction of mitochondrial A, with mitochondrial enzymes such as amyloid , binding alcohol dehydrogenase (ABAD) exaggerates mitochondrial stress by inhibiting the enzyme activity, releasing reactive oxygen species (ROS), and affecting glycolytic, Krebs cycle and/or the respiratory chain pathways through the accumulation of deleterious intermediate metabolites. The pathways proposed may play a key role in the pathogenesis of this devastating neurodegenerative disorder, Alzheimer's disease. iubmb Life, 58: 686-694, 2006 [source]

Xenobiotic metabolism, genetic polymorphisms and male infertility

ANDROLOGIA, Issue 4-5 2000
H.-C. Schuppe
Male reproductive function may be impaired by various occupational and environmental chemical agents. The majority of these xenobiotics, however, require metabolic activation in order to exert adverse effects via covalent interactions between intermediate metabolites and cellular macromolecules such as DNA or protein. In addition, metabolization may alter endocrine-disrupting properties of xenobiotics. Thus tissue-specific expression and regulation of multiple xenobiotic-metabolizing enzymes are likely to play an important role in chemically induced disorders of male reproductive organs. Recent studies suggest that genetic polymorphisms underlying inter-individual and inter-ethnic variability of xenobiotic metabolism modulate susceptibility to male reproductive disorders. For cytochrome P450 1A1 (CYP1A1), a key enzyme in extra-hepatic metabolic activation of lipophilic xenobiotics, increased frequencies of two genetically linked polymorphisms have been found among infertile men. [source]