scholarly journals Adsorption of extracellular vesicles onto the tube walls during storage in solution

PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0243738
Author(s):  
Evgeniy G. Evtushenko ◽  
Dmitry V. Bagrov ◽  
Vassili N. Lazarev ◽  
Mikhail A. Livshits ◽  
Elena Khomyakova
Keyword(s):  
Conditioned Medium ◽  
Extracellular Vesicle ◽  
Short Term ◽  
Particle Count ◽  
Diffusion Controlled ◽  
Total Particle ◽  
The Stability ◽  
Controlled Adsorption ◽  
Term Storage ◽  
Ht 29

Short term storage of extracellular vesicle (EV) solutions at +4°C is a common practice, but the stability of EVs during this procedure has not been fully understood yet. Using nanoparticle tracking analysis, we have shown that EVs isolated from the conditioned medium of HT-29 cells exhibit a pronounced concentration decrease when stored in PBS in ordinary polypropylene tubes within the range of (0.5–2.1) × 1010 particles/ml. EV losses reach 51±3% for 0.5 ml of EVs in Eppendorf 2 ml tube at 48 hours of storage at +4°C. Around 2/3 of the observed losses have been attributed to the adsorption of vesicles onto tube walls. This result shows that the lower part (up to at least 2 × 1010 particles/ml) of the practically relevant concentration range for purified EVs is prone to adsorption losses at +4°C. Total particle losses could be reduced to 18–21% at 48 hours by using either Eppendorf Protein LoBind tubes or ordinary tubes with the surface blocked with bovine serum albumin or EVs. Reduction of losses to 15% has been shown for isolated EVs dissolved in the supernatant after 100 000 g centrifugation as a model of conditioned medium. Also, a previously unknown feature of diffusion-controlled adsorption was revealed for EVs. In addition to the decrease in particle count, this process causes the predominant losses of smaller particles.

Influence of temperature and short-term storage on the stability of norepinephrine in plasma samples

1994 ◽  
Vol 348 (10) ◽  
pp. 696-698 ◽  
Author(s):  
Manfred Volz ◽  
Gisela Gottschalk ◽  
Hussein Husseini ◽  
Veselin Mitrovic ◽  
Martin Schlepper
Keyword(s):  
Plasma Samples ◽  
Short Term ◽  
Influence Of Temperature ◽  
Short Term Storage ◽  
The Stability ◽  
Term Storage

scholarly journals REPEATED FREEZE-THAW CYCLES BUT NOT SHORT-TERM STORAGE OF FECAL EXTRACTS AT AMBIENT TEMPERATURE INFLUENCE THE STABILITY OF STEROID METABOLITE LEVELS IN CRESTED MACAQUES

2017 ◽  
Vol 11 (2) ◽  
Author(s):  
Gholib Gholib ◽  
Muhammad Agil ◽  
Bambang Purwantara ◽  
Michael Heistermann ◽  
Antje Engelhardt
Keyword(s):  
Ambient Temperature ◽  
Control Group ◽  
Short Term ◽  
Freeze Thaw ◽  
North Sulawesi ◽  
Macaca Nigra ◽  
Significant Difference ◽  
Short Term Storage ◽  
The Stability ◽  
Term Storage

The objective of this study was to examine the effects of repeated freeze-thaw cycles and short-term storage of fecal extracts at ambient temperature on the stability of fecal glucocorticoid (fGCM) and estrogen metabolite (fEM) levels from crested macaques.In total 100 aliquots of fecal extracts from fecal samples collected from female crested macaques (Macaca nigra) living at the Tangkoko-Batuangus Nature Reserve, North Sulawesi were used. We performed two different experiments: (1) An experiment to investigate if levels of fGCM and fEM measured from fecal extracts that were exposed to two, four, six and eight repeated freeze-thaw cycles (test groups) differ to control samples (i.e. fecal extracts always stored frozen); (2) An experiment to evaluate whether storing fecal extracts at ambient temperature for two, four, six, and eight days (test groups)affects the levels of fGCM and fEM compared to the control group (i.e. fecal extracts frozen immediately).Results showed that hormone levels were significantly increased (P<0.05) after four freeze-thaw cycles for fGCM and after eight freeze-thaw cycles for fEM. By contrast, there was no significant difference (P>0.05) in levels of fGCM and fEM between the test groups and the control group in fecal extracts stored at ambient temperature. In conclusion, our data show that more than two and six repeated freeze-thaw cycles should be avoided when measuring fGCM and fEM in crested macaque fecal extracts, respectively. We also demonstrate that storing fecal extracts at ambient temperature is possible for at least 8 days without taking a risk of affecting the stability of fGCM and fEM levels.

Aggregation prone regions in antibody sequences raised against Vibrio cholerae: A bioinformatic approach

2020 ◽  
Vol 15 ◽  
Author(s):  
Zakia Akter ◽  
Anamul Haque ◽  
Md. Sabir Hossain ◽  
Firoz Ahmed ◽  
Md Asiful Islam
Keyword(s):  
Vibrio Cholerae ◽  
Binding Sites ◽  
Bioinformatic Analysis ◽  
Antigen Binding ◽  
Short Term ◽  
Protein Database ◽  
The Stability ◽  
Bioinformatic Approach ◽  
Self Aggregation ◽  
Complementarity Determining Region

Background: Cholera, a diarrheal illness causes millions of deaths worldwide due to large outbreaks. Monoclonal antibody used as therapeutic purposes of cholera are prone to be unstable due to various factors including self-aggregation. Objectives: In this bioinformatic analysis, we identified the aggregation prone regions (APRs) of different immunogens of antibody sequences (i.e., CTB, ZnM-CTB, ZnP-CTB, TcpA-CT-CTB, ZnM-TcpA-CT-CTB, ZnP-TcpA-CT-CTB, ZnM-TcpA, ZnP-TcpA, TcpA-CT-TcpA, ZnM-TcpA-CT-TcpA, ZnP-TcpA-CT-TcpA, Ogawa, Inaba and ZnM-Inaba) raised against Vibrio cholerae. Methods: To determine APRs in antibody sequences that were generated after immunizing Vibrio cholerae immunogens on Mus musculus, a total of 94 sequences were downloaded as FASTA format from a protein database and the algorithms such as Tango, Waltz, PASTA 2.0, and AGGRESCAN were followed to analyze probable APRs in all of the sequences. Results: A remarkably high number of regions in the monoclonal antibodies were identified to be APRs which could explain a cause of instability/short term protection of anticholera vaccine. Conclusion: To increase the stability, it would be interesting to eliminate the APR residues from the therapeutic antibodies in a such way that the antigen binding sites or the complementarity determining region loops involved in antigen recognition are not disrupted.

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