{"id":{"repo_id":"u-iceland","oai_identifier":"oai:skemman.is:1946/35098"},"canonical_url":"https://search.dev.ndltd.org/etd/u-iceland/oai:skemman.is:1946/35098","repository":{"repo_id":"u-iceland","name":"University of Iceland","base_url":"https://skemman.is/oai/request"},"display":{"title":"Biomarker analysis for APRT deficiency diagnosis using UPLC-MS/MS","abstract":"Adenine phosphoribosyltransferase (APRT) deficiency is a rare genetic disorder. Since activity of the APRT enzyme is absent, adenine is oxidized and forms 2,8-dihydroxyadenine (DHA). DHA is insoluble in urine and can precipitate and form kidney stones, which can cause acute and chronic kidney failure. The disease can be treated with the drugs allopurinol and febuxostat, which prevent the conversion of adenine to DHA and thus reduce formation of kidney stones in APRT deficiency patients. UPLC-MS/MS method for simultaneous quantification of DHA, adenine and the drugs, allopurinol, oxypurinol and febuxostat in human plasma had been developed. The objective of this study was to perform full validation of the UPLC-MS/MS quantification method according to method validation guideline from Food and Drug Administration (FDA Bioanalytical Method Validation Guidance for Industry, 2018). Following full validation of the UPLC-MS/MS method, plasma samples from patients with APRT deficiency will be studied. The sample preparation procedure was optimized prior to conductance of full validation of the UPLC-MS/MS quantification method. During the validation process, the performance of the analytical column changed, shown by a deterioration of chromatographic peak shape of the analytes and increased column pressure. Therefore, investigation of different batches of analytical columns was conducted and the results indicated that column properties changed following analysis of human plasma extracts. It was concluded that further investigation of this phenomena is needed before conducting the full validation procedure. However, due to COVID-19 epidemic the laboratory was temporarily closed before the issue could be resolved and no further work could be conducted.","abstract_html":"Adenine phosphoribosyltransferase (APRT) deficiency is a rare genetic disorder. Since activity of the APRT enzyme is absent, adenine is oxidized and forms 2,8-dihydroxyadenine (DHA). DHA is insoluble in urine and can precipitate and form kidney stones, which can cause acute and chronic kidney failure. The disease can be treated with the drugs allopurinol and febuxostat, which prevent the conversion of adenine to DHA and thus reduce formation of kidney stones in APRT deficiency patients. UPLC-MS/MS method for simultaneous quantification of DHA, adenine and the drugs, allopurinol, oxypurinol and febuxostat in human plasma had been developed. The objective of this study was to perform full validation of the UPLC-MS/MS quantification method according to method validation guideline from Food and Drug Administration (FDA Bioanalytical Method Validation Guidance for Industry, 2018). Following full validation of the UPLC-MS/MS method, plasma samples from patients with APRT deficiency will be studied. The sample preparation procedure was optimized prior to conductance of full validation of the UPLC-MS/MS quantification method. During the validation process, the performance of the analytical column changed, shown by a deterioration of chromatographic peak shape of the analytes and increased column pressure. Therefore, investigation of different batches of analytical columns was conducted and the results indicated that column properties changed following analysis of human plasma extracts. It was concluded that further investigation of this phenomena is needed before conducting the full validation procedure. However, due to COVID-19 epidemic the laboratory was temporarily closed before the issue could be resolved and no further work could be conducted.","abstract_has_math":false,"creators":["Pálmi Þorgeirsson 1992-"],"institution":null,"degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":["Háskóli Íslands"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2020,"date_issued":"2020-04-27T15:46:57Z","date_published":"2020-04-27T15:46:57Z","updated_at":"2026-07-27T21:36:01Z","subjects":["Lyfjafræði","Erfðasjúkdómar","Lyfjameðferð"],"languages":["en"],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/1946/35098","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Háskóli Íslands"]},{"key":"dc:creator","label":"Author","values":["Pálmi Þorgeirsson 1992-"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2020-04-27T15:46:56Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2020-04-27T15:46:56Z"]},{"key":"dc:date.issued","label":"Date","values":["2020-04-27T15:46:57Z"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Lyfjafræði","Erfðasjúkdómar","Lyfjameðferð"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["en"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/1946/35098"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Adenine phosphoribosyltransferase (APRT) deficiency is a rare genetic disorder. Since activity of the APRT enzyme is absent, adenine is oxidized and forms 2,8-dihydroxyadenine (DHA). DHA is insoluble in urine and can precipitate and form kidney stones, which can cause acute and chronic kidney failure. The disease can be treated with the drugs allopurinol and febuxostat, which prevent the conversion of adenine to DHA and thus reduce formation of kidney stones in APRT deficiency patients. UPLC-MS/MS method for simultaneous quantification of DHA, adenine and the drugs, allopurinol, oxypurinol and febuxostat in human plasma had been developed. The objective of this study was to perform full validation of the UPLC-MS/MS quantification method according to method validation guideline from Food and Drug Administration (FDA Bioanalytical Method Validation Guidance for Industry, 2018). Following full validation of the UPLC-MS/MS method, plasma samples from patients with APRT deficiency will be studied. The sample preparation procedure was optimized prior to conductance of full validation of the UPLC-MS/MS quantification method. During the validation process, the performance of the analytical column changed, shown by a deterioration of chromatographic peak shape of the analytes and increased column pressure. Therefore, investigation of different batches of analytical columns was conducted and the results indicated that column properties changed following analysis of human plasma extracts. It was concluded that further investigation of this phenomena is needed before conducting the full validation procedure. However, due to COVID-19 epidemic the laboratory was temporarily closed before the issue could be resolved and no further work could be conducted.","Adenine phosphoribosyltransferase (APRT) skortur er sjaldgæfur erfðasjúkdómur. Þar sem virkni APRT ensímsins er ekki til staðar er adenine umbreytt í 2,8-dihydroxyadenine (DHA). DHA er torrleyst við sýrustig þvags og getur fallið út og myndað nýrnasteina, þetta getur leitt til bráðrar og krónískrar nýrnabilunar. Hægt er að meðhöndla sjúkdóminn með lyfjunum allopurinol og febuxostat, sem koma í veg fyrir myndun á DHA og draga þannig úr nýmyndun á nýrnasteinum. UPLC-MS/MS mæliaðferð fyrir samtímis magngreiningu á DHA, adenine og lyfjunum allopurinol, oxypurinol og febuxostat í blóðvökva hefur verið þróuð. Markmið verkefnisins var að framkvæma fulla gildingu á þessari mæliaðferð, þar sem stuðst verður við verklýsingar um gildingu frá Food and Drug Administration í Bandaríkjunum (FDA Bioanalytical Method Validation Guidance for Industry, 2018). Þegar að mæliaðferðin hefur verið fullgilduð þá verða blóðvökvasýni frá sjúklingum með APRT skort rannsökuð. Sýnameðhöndlunin fyrir mæliaðferðina var betrumbætt áður en hefja átti gildinguna. Tæknilegir erfileikar varðandi súluna í UPLC-MS/MS tækjabúnaðnum sem einkenndust af hækkuðum þrýstingi og minni greiningarsvörun komu upp þegar tilraunir fyrir gildingu hófust. Rannsókn á mismunandi súlum var gerð, niðurstöðurnar bentu til þess að eiginleikar súlunnar breyttust í kjölfar greiningar á blóðvökvasýnum. Það var komist að þeirri niðurstöðu að frekari rannsókn á þessu vandamáli þyrfti að framkvæma áður en full gilding á mæliaðferðinni væri framkvæmd. Vegna COVID-19 faraldursins var rannsóknarstofunni tímabundið lokað áður en hægt var að leysa vandamálið."]},{"key":"dc:title","label":"Title","values":["Biomarker analysis for APRT deficiency diagnosis using UPLC-MS/MS","UPLC-MS/MS magngreining á lífmerkjum og lyfjum fyrir APRT skort"]}]}],"canonical_facts":{"dc:contributor":["Háskóli Íslands"],"dc:creator":["Pálmi Þorgeirsson 1992-"],"dc:date.accessioned":["2020-04-27T15:46:56Z"],"dc:date.available":["2020-04-27T15:46:56Z"],"dc:date.issued":["2020-04-27T15:46:57Z"],"dc:description.abstract":["Adenine phosphoribosyltransferase (APRT) deficiency is a rare genetic disorder. Since activity of the APRT enzyme is absent, adenine is oxidized and forms 2,8-dihydroxyadenine (DHA). DHA is insoluble in urine and can precipitate and form kidney stones, which can cause acute and chronic kidney failure. The disease can be treated with the drugs allopurinol and febuxostat, which prevent the conversion of adenine to DHA and thus reduce formation of kidney stones in APRT deficiency patients. UPLC-MS/MS method for simultaneous quantification of DHA, adenine and the drugs, allopurinol, oxypurinol and febuxostat in human plasma had been developed. The objective of this study was to perform full validation of the UPLC-MS/MS quantification method according to method validation guideline from Food and Drug Administration (FDA Bioanalytical Method Validation Guidance for Industry, 2018). Following full validation of the UPLC-MS/MS method, plasma samples from patients with APRT deficiency will be studied. The sample preparation procedure was optimized prior to conductance of full validation of the UPLC-MS/MS quantification method. During the validation process, the performance of the analytical column changed, shown by a deterioration of chromatographic peak shape of the analytes and increased column pressure. Therefore, investigation of different batches of analytical columns was conducted and the results indicated that column properties changed following analysis of human plasma extracts. It was concluded that further investigation of this phenomena is needed before conducting the full validation procedure. However, due to COVID-19 epidemic the laboratory was temporarily closed before the issue could be resolved and no further work could be conducted.","Adenine phosphoribosyltransferase (APRT) skortur er sjaldgæfur erfðasjúkdómur. Þar sem virkni APRT ensímsins er ekki til staðar er adenine umbreytt í 2,8-dihydroxyadenine (DHA). DHA er torrleyst við sýrustig þvags og getur fallið út og myndað nýrnasteina, þetta getur leitt til bráðrar og krónískrar nýrnabilunar. Hægt er að meðhöndla sjúkdóminn með lyfjunum allopurinol og febuxostat, sem koma í veg fyrir myndun á DHA og draga þannig úr nýmyndun á nýrnasteinum. UPLC-MS/MS mæliaðferð fyrir samtímis magngreiningu á DHA, adenine og lyfjunum allopurinol, oxypurinol og febuxostat í blóðvökva hefur verið þróuð. Markmið verkefnisins var að framkvæma fulla gildingu á þessari mæliaðferð, þar sem stuðst verður við verklýsingar um gildingu frá Food and Drug Administration í Bandaríkjunum (FDA Bioanalytical Method Validation Guidance for Industry, 2018). Þegar að mæliaðferðin hefur verið fullgilduð þá verða blóðvökvasýni frá sjúklingum með APRT skort rannsökuð. Sýnameðhöndlunin fyrir mæliaðferðina var betrumbætt áður en hefja átti gildinguna. Tæknilegir erfileikar varðandi súluna í UPLC-MS/MS tækjabúnaðnum sem einkenndust af hækkuðum þrýstingi og minni greiningarsvörun komu upp þegar tilraunir fyrir gildingu hófust. Rannsókn á mismunandi súlum var gerð, niðurstöðurnar bentu til þess að eiginleikar súlunnar breyttust í kjölfar greiningar á blóðvökvasýnum. Það var komist að þeirri niðurstöðu að frekari rannsókn á þessu vandamáli þyrfti að framkvæma áður en full gilding á mæliaðferðinni væri framkvæmd. Vegna COVID-19 faraldursins var rannsóknarstofunni tímabundið lokað áður en hægt var að leysa vandamálið."],"dc:identifier.uri":["http://hdl.handle.net/1946/35098"],"dc:language.iso":["en"],"dc:subject":["Lyfjafræði","Erfðasjúkdómar","Lyfjameðferð"],"dc:title":["Biomarker analysis for APRT deficiency diagnosis using UPLC-MS/MS","UPLC-MS/MS magngreining á lífmerkjum og lyfjum fyrir APRT skort"],"dc:type":["Thesis"]},"updated_at":"2026-07-27T21:36:01Z"}