scholarly journals The proteome of the human endolymphatic sac endolymph

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Christine Ölander ◽  
Jesper Edvardsson Rasmussen ◽  
Per Olof Eriksson ◽  
Göran Laurell ◽  
Helge Rask-Andersen ◽  
...  
Keyword(s):  
Inner Ear ◽  
Solid Phase ◽  
Sampling Technique ◽  
Endolymphatic Sac ◽  
Molecular Function ◽  
Chromatography Tandem Mass Spectrometry ◽  
Liquid Chromatography Tandem Mass ◽  
Nano Liquid Chromatography

AbstractThe endolymphatic sac (ES) is the third part of the inner ear, along with the cochlea and vestibular apparatus. A refined sampling technique was developed to analyse the proteomics of ES endolymph. With a tailored solid phase micro-extraction probe, five ES endolymph samples were collected, and six sac tissue biopsies were obtained in patients undergoing trans-labyrinthine surgery for sporadic vestibular schwannoma. The samples were analysed using nano-liquid chromatography-tandem mass spectrometry (nLC-MS/MS) to identify the total number of proteins. Pathway identification regarding molecular function and protein class was presented. A total of 1656 non-redundant proteins were identified, with 1211 proteins detected in the ES endolymph. A total of 110 proteins were unique to the ES endolymph. The results from the study both validate a strategy for in vivo and in situ human sampling during surgery and may also form a platform for further investigations to better understand the function of this intriguing part of the inner ear.

scholarly journals An online solid-phase extraction–liquid chromatography–tandem mass spectrometry method to study the presence of thyronamines in plasma and tissue and their putative conversion from 13C6-thyroxine

2010 ◽  
Vol 206 (3) ◽  
pp. 327-334 ◽  
Author(s):  
M T Ackermans ◽  
L P Klieverik ◽  
P Ringeling ◽  
E Endert ◽  
A Kalsbeek ◽  
...  
Keyword(s):  
Solid Phase ◽  
Thyroid Tissue ◽  
Spectrometry Method ◽  
Tissue Samples ◽  
Chromatography Tandem Mass Spectrometry ◽  
Online Solid Phase Extraction ◽  
Liquid Chromatography Tandem Mass ◽  
Negative Findings ◽  
Insufficient Sensitivity

Thyronamines are exciting new players at the crossroads of thyroidology and metabolism. Here, we report the development of a method to measure 3-iodothyronamine (T1AM) and thyronamine (T0AM) in plasma and tissue samples. The detection limit of the method was 0.25 nmol/l in plasma and 0.30 pmol/g in tissue both for T1AM and for T0AM. Using this method, we were able to demonstrate T1AM and T0AM in plasma and liver from rats treated with synthetic thyronamines. Although we demonstrated the in vivo conversion of 13C6-thyroxine (13C6-T4) to 13C6-3,5,3′-triiodothyronine, we did not detect 13C6-T1AM in plasma or brain samples of rats treated with 13C6-T4. Surprisingly, our method did not detect any endogenous T1AM or T0AM in plasma from vehicle-treated rats, nor in human plasma or thyroid tissue. Although we are cautious to draw general conclusions from these negative findings and in spite of the fact that insufficient sensitivity of the method related to extractability and stability of T0AM cannot be completely excluded at this point, our findings raise questions on the biosynthetic pathways and concentrations of endogenous T1AM and T0AM.

scholarly journals Magnetic Solid-Phase Extraction and in Situ Derivatization for Determining Phytohormones and in Oilseeds by Ultra-Performance Liquid Chromatography-tandem Mass Spectrometry

2020 ◽  
Author(s):  
Zhoufei Luo ◽  
Mengwei Xu ◽  
Ruozhong Wang ◽  
Xiubing Liu ◽  
Langtao Xiao
Keyword(s):  
Solid Phase Extraction ◽  
Solid Phase ◽  
Magnetic Solid Phase Extraction ◽  
Ultra Performance Liquid Chromatography ◽  
Phase Extraction ◽  
Chromatography Tandem Mass Spectrometry ◽  
Liquid Chromatography Tandem Mass ◽  
Magnetic Solid

Abstract Background: Phytohormones are a group of naturally occurring signaling molecules which influence physiological processes of oil crops. Simultaneous determination of multiple phytohormones in oilseeds is still a challenge due to their trace concentrations, species diversity, and lipid interference. Therefore, a simple and selective method for the simultaneous determination of multiple phytohormones in oilseeds is urgently needed.Results: In this study, the Fe3O4@Ti3C2@β-CD nanoparticles were successfully synthesized and used for the first time as an adsorbent for the magnetic dispersive solid-phase extraction of phytohormones from oilseeds. The magnetic dispersive solid-phase extraction and in situ derivation by the addition of N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide (EDC) were ingeniously combined. This efficient pre-treatment method integrated the extraction, purification, and derivatization processes into one single step. Several parameters affecting the efficiency of extraction and derivatization were evaluated. Under the optimized analysis conditions, satisfactory methodological performance was achieved. High linearities (R2 > 0.9928) at three spiked levels, as well as the low matrix effect (ranged from ­16.63 % to 17.06 %) and limits of detection (0.89-13.62 pg/mL) were also obtained. The intra and inter-day relative standard deviations (RSDs) were less than 13.7 % and 11.6 %, respectively. The recoveries were ranged from 80.4 % to 115.1 %. This method was successfully employed for analyzing 12 phytohormones in different oilseeds samples.Conclusion: A simple and sensitive method based on the magnetic solid phase extraction integrated with in situ derivations for the profiling of 12 phytohormones, including 9 gibberellins (GAs), indole-3-acetic acid (IAA), abscisic acid (ABA), and jasmonic acid (JA) in a single rapeseed seed was developed by using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS).

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