Further Development and Application of an LC/MS Analysis of Plasma Oxysterol
Başlık:
Further Development and Application of an LC/MS Analysis of Plasma Oxysterol
Yazar:
Bhattacharya, Sonia Bholanath, author.
ISBN:
9780438047846
Yazar Ek Girişi:
Fiziksel Tanımlama:
1 electronic resource (74 pages)
Genel Not:
Source: Masters Abstracts International, Volume: 57-06M(E).
Advisors: Richard W. Browne Committee members: Paul J. Kostyniak; Murali Ramanathan.
Özet:
Importance: Oxysterols are biologically active derivatives of cholesterol of recent interest that encompass roles in signaling, regulation, immunity and disease biomarker amongst others. We examined the liquid chromatography-mass spectrometry (LC-MS) analysis of 6 clinically relevant oxysterols in order to improve the quantitation, chromatographic resolution and assay throughput. We also explore the use oxysterols as biomarkers in diagnosing and delineating clinical phenotypes of multiple sclerosis.
Method: We evaluated the effect of column temperature, mobile phase solvent [acetonitrile (ACN) or methanol] and stationary phase chemistries [alkyl-silica (C18 and C8), biphenyl and aqueous (polar) C18] on chromatographic resolution and run-time of underivatized oxysterols. We applied the optimized method to a prospective, longitudinal study including 139 subjects [39 healthy controls, 61 relapsing-remitting MS (RR-MS), 39 progressive MS (P-MS)] to measure oxysterol levels at baseline and 5-year follow-up.
Results: Traditional C18 (ODS) exhibited the greatest selectivity among the stationary phases tested. Colder column temperatures improve resolution for all stationary phases. Increased ACN enhanced resolution and shortened analytical runtime but decreased MS detector signal. Levels of 24-HC (p = 0.004), 25-HC (p = 0.029) and 27-HC (p = 0.026) were increased in P-MS patients while levels of 7-KC (p = 0.047) and 7a-HC (p = 0.001) were decreased in RR-MS patients with no changes in healthy controls, all over the period of 5-years.
Conclusion: Direct analysis of underivatized oxysterols is favored by colder column temperature using a C18 stationary phases and methanol based solvent gradient. The oxysterol network seems to be disrupted in MS patients compared to healthy control.
Notlar:
School code: 0656
Tüzel Kişi Ek Girişi:
Mevcut:*
Yer Numarası | Demirbaş Numarası | Shelf Location | Lokasyon / Statüsü / İade Tarihi |
---|---|---|---|
XX(692806.1) | 692806-1001 | Proquest E-Tez Koleksiyonu | Arıyor... |
On Order
Liste seç
Bunu varsayılan liste yap.
Öğeler başarıyla eklendi
Öğeler eklenirken hata oldu. Lütfen tekrar deneyiniz.
:
Select An Item
Data usage warning: You will receive one text message for each title you selected.
Standard text messaging rates apply.