The effects of a freeze-thaw cycle and pre-analytical storage temperature on the stability of insulin-like growth factor-I and pro-collagen type III N-terminal propeptide concentrations: Implications for the detection of growth hormone misuse in athletes

2012 ◽  
Vol 4 (6) ◽  
pp. 455-459 ◽  
Author(s):  
Nishan Guha ◽  
Ioulietta Erotokritou-Mulligan ◽  
Christiaan Bartlett ◽  
David A. Cowan ◽  
E. Eryl Bassett ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Growth Factor ◽  
Collagen Type ◽  
Storage Temperature ◽  
Collagen Type Iii ◽  
Freeze Thaw ◽  
Factor I ◽  
Thaw Cycle ◽  
Freeze Thaw Cycle ◽  
The Stability

The Effect of Freeze/Thaw Cycles on the Stability of Compounds in DMSO

2003 ◽  
Vol 8 (2) ◽  
pp. 210-215 ◽  
Author(s):  
Barbara A. Kozikowski ◽  
Thomas M. Burt ◽  
Debra A. Tirey ◽  
Lisa E. Williams ◽  
Barbara R. Kuzmak ◽  
...  
Keyword(s):  
High Throughput Screening ◽  
High Performance ◽  
Atmospheric Conditions ◽  
Freeze Thaw ◽  
Thaw Cycle ◽  
Time Period ◽  
Freeze Thaw Cycle ◽  
Low Humidity ◽  
The Stability ◽  
Short Time

A diverse set of 320 compounds from the Procter & Gamble Pharmaceuticals organic compound repository was prepared as 20-mM DMSO solutions and stored at 4°C under argon in pressurized canisters to simulate a low-humidity environment. The plates were subjected to 25 freeze/thaw cycles while being exposed to ambient atmospheric conditions after each thaw to simulate the time and manner by which compound plates are exposed to the atmosphere during typical liquid-handling and high-throughput screening processes. High-performance liquid chromatography–mass spectrometry with evaporative light-scattering detection was used to quantitate the amount of compound remaining after every 5th freeze/thaw cycle. Control plates were stored either at room temperature under argon or at 4°C under argon without freeze/thaw cycling and were evaluated at the midpoint and the endpoint of the study. The study was conducted over a short time period (i.e., 7 weeks) to minimize the effect of compound degradation over time due to the exposure of the compounds to DMSO.The results from this study will be used to determine the maximum number of freeze/thaw cycles that can be achieved while maintaining acceptable compound integrity.(Journal of Biomolecular Screening 2003:210-215)

scholarly journals Effects of Serum Stored at Various Temperature and FreezeThaw Cycles on Selected Biochemical Parameters

2016 ◽  
Vol 15 (1) ◽  
Author(s):  
Nor Zamzila Abdullah ◽  
Norlelawati A. Talib ◽  
Nor Sidah Ku Zaifah ◽  
Abdul Hadi Mohamed ◽  
Naznin Muhammad ◽  
...  
Keyword(s):  
Biochemical Parameters ◽  
Large Scale ◽  
Storage Temperature ◽  
Density Lipoprotein ◽  
Storage Conditions ◽  
Freeze Thaw ◽  
Thaw Cycle ◽  
Freeze Thaw Cycle ◽  
Extended Duration ◽  
Positive Correlations

Introduction: Preanalytical variation as a result of sample storage conditions are common issues in a large scale study since the sample has to be kept for an extended duration at ultra low temperature (-70ºC) before analysis. However, ultra low freezers may not be available in some laboratories. Sometimes, the laboratory test may need to be repeated on the previously frozen and thawed samples. The aim of this research was to study the effect of storage temperature and freeze-thaw cycles on some biochemical parameters in our laboratory. Methods: An experimental study was carried out on 50 volunteers. Serum were aliquoted and stored at 4ºC, -30ºC and -70ºC. The serum was analyzed for total cholesterol (TC), triglycerides (TG), high density-lipoprotein (HDL-C) and glucose after 3 months of storage. The effects of freeze-thaw cycles were also recorded. Results: No significant differences (p>0.05) were seen in the level of the biochemical parameters between the samples stored at -70ºC and at -30ºC. The levels of selected parameters were higher after second freeze-thaw cycles as compared to the first thaw. All parameters showed significant positive correlations between the samples stored at -70ºC and the samples stored at -30ºC and 4ºC as well as between the first and second freeze-thaw cycles in samples kept at both -70ºC and -30ºC. Conclusions: Our finding suggested that the level of TC, TG and glucose in sample stored for 3 months at -70ºC are comparable with the samples stored at -30ºC. Only one freeze-thaw cycle is acceptable.

scholarly journals Stability of Plasma Amyloid-β 1–40, Amyloid-β 1–42, and Total Tau Protein over Repeated Freeze/Thaw Cycles

2020 ◽  
Vol 10 (1) ◽  
pp. 46-55
Author(s):  
Huei-Chun Liu ◽  
Ming-Jang Chiu ◽  
Chin-Hsien Lin ◽  
Shieh-Yueh Yang
Keyword(s):  
Tau Protein ◽  
Statistical Significance ◽  
Amyloid Β ◽  
Freeze Thaw ◽  
Total Tau ◽  
Thaw Cycle ◽  
Freeze Thaw Cycle ◽  
Fresh Plasma ◽  
The Stability ◽  
T Tau

Introduction: Blood biomarkers of Alzheimer’s disease (AD) have attracted much attention of researchers in recent years. In clinical studies, repeated freeze/thaw cycles often occur and may influence the stability of biomarkers. This study aims to investigate the stability of amyloid-β 1–40 (Aβ1–40), amyloid-β 1–42 (Aβ1–42), and total tau protein (T-tau) in plasma over freeze/thaw cycles. Methods: Plasma samples from healthy controls (n = 2), AD patients (AD, n =3) and Parkinson’s disease patients (PD, n = 3) were collected by standardized procedure and immediately frozen at –80°C. Samples underwent 5 freeze/thaw (–80°C/room temperature) cycles. The concentrations of Aβ1–40, Aβ1–42, and T-tau were monitored during the freeze/thaw tests using an immunomagnetic reduction (IMR) assay. The relative percentage of concentrations after every freeze/thaw cycle was calculated for each biomarker. Results: A tendency of decrease in the averaged relative percentages over samples through the freeze and thaw cycles for Aβ1–40 (100 to 97.11%), Aβ1–42 (100 to 94.99%), and T-tau (100 to 95.65%) was found. However, the decreases were less than 6%. For all three biomarkers, no statistical significance was found between the levels of fresh plasma and those of the plasma experiencing 5 freeze/thaw cycles (p > 0.1). Conclusions: Plasma Aβ1–40, Aβ1–42, and T-tau are stable through 5 freeze/thaw cycles measured with IMR.

scholarly journals Effects of Processing and Storage Conditions on Amyloid β (1–42) and Tau Concentrations in Cerebrospinal Fluid: Implications for Use in Clinical Practice

2005 ◽  
Vol 51 (1) ◽  
pp. 189-195 ◽  
Author(s):  
Niki SM Schoonenboom ◽  
Cees Mulder ◽  
Hugo Vanderstichele ◽  
Evert-Jan Van Elk ◽  
Astrid Kok ◽  
...  
Keyword(s):  
Cerebrospinal Fluid ◽  
Storage Temperature ◽  
Amyloid Β ◽  
Quantitative Result ◽  
Storage Conditions ◽  
Freeze Thaw ◽  
Thaw Cycle ◽  
Freeze Thaw Cycle ◽  
Processing And Storage ◽  
And Storage

Abstract Background: Reported concentrations of amyloid β (1–42) (Aβ42) and tau in cerebrospinal fluid (CSF) differ among reports. We investigated the effects of storage temperature, repeated freeze/thaw cycles, and centrifugation on the concentrations of Aβ42 and tau in CSF. Methods: Stability of samples stored at −80 °C was determined by use of an accelerated stability testing protocol according to the Arrhenius equation. Aβ42 and tau concentrations were measured in CSF samples stored at 4, 18, 37, and −80 °C. Relative CSF concentrations (%) of the biomarkers after one freeze/thaw cycle were compared with those after two, three, four, five, and six freeze/thaw cycles. In addition, relative Aβ42 and tau concentrations in samples not centrifuged were compared with samples centrifuged after 1, 4, 48, and 72 h. Results: Aβ42 and tau concentrations were stable in CSF when stored for a long period at −80 °C. CSF Aβ42 decreased by 20% during the first 2 days at 4, 18, and 37 °C compared with −80 °C. CSF tau decreased after storage for 12 days at 37 °C. After three freeze/thaw cycles, CSF Aβ42 decreased 20%. CSF tau was stable during six freeze/thaw cycles. Centrifugation did not influence the biomarker concentrations. Conclusions: Repeated freeze/thaw cycles and storage at 4, 18, and 37 °C influence the quantitative result of the Aβ42 test. Preferably, samples should be stored at −80 °C immediately after collection.

scholarly journals The Effects of a Single Freeze-Thaw Cycle on Concentrations of Nutritional, Noncommunicable Disease, and Inflammatory Biomarkers in Serum Samples

2021 ◽  
Author(s):  
Ransi Ann Abraham ◽  
Garima Rana ◽  
Praween K. Agrawal ◽  
Robert Johnston ◽  
Avina Sarna ◽  
...  
Keyword(s):  
Large Scale ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Noncommunicable Disease ◽  
Noncommunicable Diseases ◽  
Serum Samples ◽  
Freeze Thaw ◽  
Thaw Cycle ◽  
Freeze Thaw Cycle ◽  
The Stability

Abstract Background The stability of biological samples is vital for reliable measurements of biomarkers in large-scale survey settings, which may be affected by freeze-thaw procedures. We examined the effect of a single freeze-thaw cycle on 13 nutritional, noncommunicable diseases (NCD), and inflammatory bioanalytes in serum samples. Method Blood samples were collected from 70 subjects centrifuged after 30 minutes and aliquoted immediately. After a baseline analysis of the analytes, the samples were stored at − 70°C for 1 month and reanalyzed for all the parameters. Mean percentage differences between baseline (fresh blood) and freeze-thaw concentrations were calculated using paired sample t-tests and evaluated according to total allowable error (TEa) limits (desirable bias). Results Freeze-thaw concentrations differed significantly (p < 0.05) from baseline concentrations for soluble transferrin receptor (sTfR) (− 5.49%), vitamin D (− 12.51%), vitamin B12 (− 3.74%), plasma glucose (1.93%), C-reactive protein (CRP) (3.45%), high-density lipoprotein (HDL) (7.98%), and cholesterol (9.76%), but they were within respective TEa limits. Low-density lipoprotein (LDL) (− 0.67%), creatinine (0.94%), albumin (0.87%), total protein (1.00%), ferritin (− 0.58%), and triglycerides (TAG) (2.82%) concentrations remained stable following the freeze-thaw cycle. In conclusion, single freeze-thaw cycle of the biomarkers in serum/plasma samples after storage at − 70°C for 1 month had minimal effect on stability of the studied analytes, and the changes in concentration were within acceptable limit for all analytes.

Phenotyping of Hyperlipoproteinemias

1970 ◽  
Vol 16 (6) ◽  
pp. 507-511 ◽  
Author(s):  
James Winkelman ◽  
Donald R Wybenga ◽  
Frank A Ibbott
Keyword(s):  
Cellulose Acetate ◽  
Room Temperature ◽  
Cellulose Acetate Electrophoresis ◽  
Freeze Thaw ◽  
Thaw Cycle ◽  
Freeze Thaw Cycle ◽  
The Stability

Abstract The stability of serum specimens collected for cellulose acetate electrophoresis of lipoproteins has been studied for each of the hyperlipoproteinemia phenotypes. In general, samples kept at room temperature for three days are still suitable for analysis. On longer standing, artifacts can cause misinterpretation of strips, or render them completely unreadable. If specimens are stored at refrigerator or freezer temperatures, deterioration is retarded but the period of stability after they are returned to room temperature is unaltered. A second freeze-thaw cycle makes specimens unsuitable for analysis. Samples can be stored at refrigerator temperatures for at least 28 days and at freezer temperatures for at least 14 days if one freeze-thaw cycle is used.

scholarly journals The Influence of Regional Freeze–Thaw Cycles on Loess Landslides: Analysis of Strength Deterioration of Loess with Changes in Pore Structure

Water ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 3047
Author(s):  
Zuyong Li ◽  
Gengshe Yang ◽  
Hui Liu
Keyword(s):  
Pore Structure ◽  
Triaxial Compression ◽  
Strength Loss ◽  
Loess Landslide ◽  
Strength Deterioration ◽  
Freeze Thaw ◽  
Thaw Cycle ◽  
Freeze Thaw Cycle ◽  
Loess Landslides ◽  
The Stability

The loess landslide in Gaoling District of Xi’an, Shaanxi in China is closely related to the seasonal freeze–thaw cycle, which is manifested by the destruction of pore structure and strength deterioration of the loess body under freeze–thaw conditions. In order to study the relationship between macro-strength damage and pore structure deterioration of saturated loess under freeze–thaw conditions and its influence on the stability of landslides, this paper explores the effect of freeze–thaw cycles on the strength of saturated undisturbed loess through triaxial compression test, and explores the micro-microstructure changes of saturated undisturbed loess through scanning electron microscopy (SEM) and nuclear magnetic resonance (NMR). This is to analyze the evolution of the pore structure and strength loss evolution of saturated loess during the freeze–thaw process, and to describe the freeze–thaw damage of saturated undisturbed loess through the change of porosity and strength deterioration. Then, the internal correlation expression between the porosity change and the strength degradation is established to realize the verification analysis of the test data based on the correlation model. The research results show that: (1) As the number of freeze–thaw cycles increases, the peak strength loss rate gradually increases, and the strength deterioration of saturated loess becomes more and more obvious. (2) The freeze–thaw cycle will lead to the development of pores and cracks in the sample, accompanied by the generation of new cracks, which will cause the deterioration of the pore structure of the sample as a whole. (3) The response of strength damage and porosity deterioration of saturated undisturbed loess is roughly similar under the freeze–thaw cycle. The change in porosity can be measured to better reflect the strength deterioration of saturated loess. Therefore, the change of pore structure of undisturbed loess under freeze–thaw cycle conditions is tested by field sampling and indoor tests to reflect the phenomenon of strength deterioration, thereby analyzing the stability of loess slopes.

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