Non-Proteinogenic Amino Acids最新文献

{"title":"How Homocysteine Modulates the Function of Osteoblasts and Osteocytes","authors":"Vijith Vijayan, Sarika Gupta","doi":"10.5772/INTECHOPEN.76398","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.76398","url":null,"abstract":"Over the years, numerous mechanisms have been identified through which homocys - teine affects osteoblast functioning. These include alterations in collagen structure, epi genetic modifications and changes in RANKL-OPG production by osteoblasts. These mechanisms are reviewed in this chapter. We have also herein discussed how homocys teine affects osteocyte behavior. With onset of hyperhomocysteinemia induction of osteo - cyte specific genes particularly the mineralization genes like Dmp1 and Sost is facilitated producing untoward mineralization, osteocyte apoptosis, deviations from regular bone remodeling process and onset of targeted remodeling in bone. These modifications have immense effect on the overall mechanical stability of bone. Homocysteine thus represents an independent risk factor for bone fragility. parathyroid hormone, growth hormone, thyroid hormones, glucocorti -coids, bone morphogenetic proteins, prostaglandins, sex hormones, various cytokines and the molecular triad comprising of OPG (osteoprotegerin), receptor activator of nuclear factor-κB ligand (RANKL) and receptor activator of nuclear factor-κB (RANK). The cells involved in the process are osteoblasts, osteoclasts, osteocytes, immune cells, megakaryocytes and osteomacs. suggested a 3 levels) homocysteine levels. conclusions that cbs is a primary 1,25(OH) 2 D 3 target gene which renders homocysteine metabolism responsive to 1,25(OH) 2","PeriodicalId":367830,"journal":{"name":"Non-Proteinogenic Amino Acids","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130903448","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Is Homocysteine a Marker or a Risk Factor: A Question Still Waits for an Answer","authors":"Cristiana Filip, Elena Albu, Hurjui Ion, Catalina Filip, Cuciureanu Magda, Radu Florin Popa, Demetra Gabriela Socolov, Ovidiu Alexa and Alexandru Filip","doi":"10.5772/INTECHOPEN.81799","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.81799","url":null,"abstract":"Homocysteine, a non-proteinogenic sulfur-containing amino acid, was discovered in 1932, and 30 years passed until, in 1969, for the first time, its involvement in pathology was reported. It was only in the last two decades that homocysteine has become a subject of scientific interest and has begun to be intensively studied. A large number of scien tists consider homocysteine as an independent risk factor particularly for cardiovascular disease, while others indicate homocysteine as a marker of this disease. Both sides bring scientific arguments for their opinions, yet the dilemma of homocysteine characterization still persists. Although the reported studies do not lead to a unique answer, it is generally accepted that homocysteine is associated with vascular dysfunction. Numerous scien- tific data show that the link between homocysteine and inflammation is achieved via the reactive oxygen species (ROS) pathway. The latest data indicate hydrogen peroxide as a possible messenger in cellular signaling in physiological or pathological processes and present the consequences of disturbing the oxidation-reducing balance . In this chapter, we present the latest scientific evidences gathered from the literature for both hypotheses regarding homocysteine involvement in pathology, and we propose a possible mecha- nism of action for homocysteine, based on our preliminary (yet unpublished) work. to the activity of reactive species, and recent data indicate protein-tyrosine phosphatases as key factors in regulating intracellular signaling pathways. These proteins allow regulation because they can undergo reversible oxidation phenomena due to the presence in their structure of cysteine residues bearing SH groups. The structural similarity of Cys with homocysteine draws attention to the possibility that Hcy may interfere with cysteine functions. In conclu sion, the recent association of Hcy with both inflammation and the reactive species involved in cellular signaling indicates that homocysteine remains a topic of interest and attention in current research. It is obvious that HHcy is an issue of interest in contemporary medicine.","PeriodicalId":367830,"journal":{"name":"Non-Proteinogenic Amino Acids","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125182183","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Introductory Chapter: General Aspects Regarding Homocysteine","authors":"Nina Filip, C. Iancu","doi":"10.5772/INTECHOPEN.81306","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.81306","url":null,"abstract":"The first description of homocysteine (Hcy), a non-proteinogenic amino acid, was introduced within a case study in 1932. The first patient was an 8-year-old child with a mental retardation disorder who died of a myocardial infarction. Meanwhile, research continued; in 1969, Dr. Kilmer McCully was the first to describe the vascular pathology in patients with homocystinuria associated with hemodynamic changes, progressive arterial stenosis, and proliferation of smooth muscle cells. He also noted that homocysteine may have a causal role in any metabolic abnormality. This idea is the basis of his theory that a moderately elevated level of homocysteine is an important risk factor for cardiovascular disease. His theory was sustained only in 1976 through a clinical trial demonstrating an increase in coronary artery disease in people with hyperhomocysteinemia. Since then, a particular interest has been given to studying this relationship.","PeriodicalId":367830,"journal":{"name":"Non-Proteinogenic Amino Acids","volume":"138 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132579161","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"HPLC Analysis of Homocysteine and Related Compounds","authors":"M. Wada, Shinichi Nakamura, K. Nakashima","doi":"10.5772/INTECHOPEN.75030","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.75030","url":null,"abstract":"Homocysteine (Hcy), a sulfur-containing amino acid, is a representative intermediate metabolite of methionine (Met) to cysteine (Cys) via several intermediates. An elevated level of Hcy in plasma plays an important role in diseases such as neural tube defects and Down syndrome. Homocystinuria is the most common inborn error of sulfur metabolism and is caused by mutations in the metabolic enzymes of Hcy. These errors can be caused by abnormal levels of Met metabolites and classified on the basis of plasma Met levels. Additionally, Hcy and related compounds such as glutathione play an important role in maintaining homeostasis. Therefore, the simultaneous determination of Hcy and/or related compounds is required for appropriate clinical management of several diseases. The sulfur-containing amino acids and their derivatives in biological samples are quantified sensitively using high-performance liquid chromatography methods coupled with various detection methods such as UV/Vis, fluorescence, chemiluminescence, electrochemical, mass spectrometry, and tandem mass spectrometry. In this chapter, we review recent advances in these analytical methods and their applications.","PeriodicalId":367830,"journal":{"name":"Non-Proteinogenic Amino Acids","volume":"162 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122396495","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}