scholarly journals Stability of Glucose Concentrations in Frozen Plasma

2020 ◽  
pp. 193229682096365
Author(s):  
Stefan Pleus ◽  
Guido Freckmann ◽  
Annette Baumstark ◽  
Cornelia Haug
Keyword(s):  
Venous Blood ◽  
Relative Difference ◽  
Plasma Samples ◽  
Conflicting Information ◽  
Long Term Storage ◽  
The Stability ◽  
Relative Differences ◽  
Frozen Plasma ◽  
Laboratory Analyzer

Background: Conflicting information is available regarding the stability of glucose concentrations in frozen plasma samples. Clinical trials could benefit from such long-term storage because it would allow usage of a central laboratory with higher-quality laboratory analyzers in contrast to mobile analyzers in a decentralized setting. Methods: In this study, venous blood samples were collected in lithium-heparin gel tubes. Plasma was separated immediately after blood was drawn, and from each of the 21 plasma samples, 6 aliquots were prepared for measurement at 6 time points: immediately and after 2, 4, 6, 8, and 12 weeks. Between sampling and measurement, aliquots were stored at less than −20°C. Transport on dry ice was simulated by placing aliquots in a −80°C freezer for 5 days between weeks 8 and 12. Measurements were performed on a hexokinase-based laboratory analyzer. Average relative differences and corresponding 99% confidence intervals (CIs) were calculated between the stored aliquots’ and the immediately measured aliquots’ glucose concentrations. Glucose concentrations were deemed stable as long as average relative differences were ≤±2.5%. Results: Over the whole 12-weeks duration, the largest average relative difference was −1.82% (99% CI: –2.25% to −1.39%). Shorter storage durations tended to lead to less bias. Conclusion: In this study, the stability of glucose concentrations in frozen plasma samples obtained with lithium-heparin gel tubes could be shown for up to 12 weeks. Future studies should be performed to assess whether this is independent of the glucose analyzer and the type of sampling tube used.

scholarly journals Long-Term Storage Effects on Stability of Aβ1–40, Aβ1–42, and Total Tau Proteins in Human Plasma Samples Measured with Immunomagnetic Reduction Assays

2019 ◽  
Vol 9 (1) ◽  
pp. 77-86 ◽  
Author(s):  
Ming-Jang Chiu ◽  
Lih-Fen Lue ◽  
Marwan N. Sabbagh ◽  
Ta-Fu Chen ◽  
H.H. Chen ◽  
...  
Keyword(s):  
Human Plasma ◽  
Plasma Levels ◽  
Plasma Samples ◽  
Total Tau ◽  
Long Term Storage ◽  
Human Plasma Samples ◽  
The Stability ◽  
T Tau ◽  
Term Storage

Background: The stability of Alzheimer’s disease (AD) biomarkers in plasma, measured by immunomagnetic reduction (IMR) after long-term storage at –80°C, has not been established before. Method: Ninety-nine human plasma samples from 53 normal controls (NCs), 5 patients with amnestic mild cognitive impairment (aMCI), and 41 AD patients were collected. Each plasma sample was aliquoted and stored as single-use aliquots at –80°C. The baseline measurements for Aβ1–40, Aβ1–42, and total Tau protein (T-Tau) concentrations for each sample were done within 3 months of blood draw by IMR. They are referred to as baseline concentrations. A separate aliquot from each sample was assayed with IMR to assess the stability of the measured analytes during storage at –80°C between 1.1 and 5.4 years. This is referred to as a repeated result. Results: IMR shows that plasma levels of Aβ1–40 and Aβ1–42 exhibit stability over 5-year storage at –80°C and that plasma levels of T-Tau are less stable (approximately 1.5 years). Conclusion: Although the measured concentrations of T-Tau in human plasma may alter during storage, the diagnostic utility of the results are only slightly affected when the product of Aβ1–42 and T-Tau concentrations are used. The results show that the overall agreement between baseline and repeated measurements in the ability of discriminating NCs from aMCI/AD patients is higher than 80%.

Stability of 5-fluorouracil in whole blood and plasma.

1987 ◽  
Vol 33 (12) ◽  
pp. 2299-2300 ◽  
Author(s):  
R F Murphy ◽  
F M Balis ◽  
D G Poplack
Keyword(s):  
Whole Blood ◽  
Enzymatic Degradation ◽  
Room Temperature ◽  
Parent Drug ◽  
Plasma Samples ◽  
Blood Specimens ◽  
The Stability ◽  
Frozen Plasma

Abstract We studied the stability of 5-fluorouracil (5-FU) in plasma and whole blood kept at room temperature and on ice for 1 to 24 h. At room temperature, there was a steady loss of 94% of the parent drug over 24 h in whole blood and 52% in plasma. In the presence of an excess of uracil, 5-FU was stable for 24 h, suggesting that the loss of 5-FU is the result of enzymatic degradation. 5-FU is more stable in whole blood and plasma when samples are kept cold. For blood and plasma samples maintained on ice, the loss was only 30% and 10% of the parent drug in the respective samples over 24 h. Frozen plasma samples (-20 degrees C) were stable for five weeks. Blood specimens collected for quantifying 5-FU should be immediately placed on ice, and the plasma should be separated and frozen as promptly as possible.

Stability and epimerisation behaviour of ergot alkaloids in various solvents

2008 ◽  
Vol 1 (1) ◽  
pp. 67-78 ◽  
Author(s):  
M. Hafner ◽  
M. Sulyok ◽  
R. Schuhmacher ◽  
C. Crews ◽  
R. Krska
Keyword(s):  
Degradation Products ◽  
Ergot Alkaloids ◽  
Carbonate Buffer ◽  
Long Term Storage ◽  
No Formation ◽  
Temperature Levels ◽  
The Stability ◽  
Extraction Mixture ◽  
Term Storage

In this paper the stability and degree of epimerisation of six major ergot alkaloids at three different temperature levels (-20 °C, +4 °C and +20 °C) over periods of 18 hours and six weeks is reported for the first time. The behaviour of ergometrine, ergocornine, ergocristine, α-ergocryptine, ergosine and ergotamine was thoroughly studied in seven solvents which are employed for the preparation of calibrants and extraction mixtures, respectively. Moreover, the stability of the ergot alkaloids was tested in different cereal extracts (rye, wheat, barley, oats) for 1, 2 and 6 days. Of the toxins tested, the ergopeptide-type toxins ergosine, ergotamine, ergocornine, α-ergocryptine and ergocristine showed similar behaviour patterns. The simple lysergic acid derivative ergometrine was more stable and showed hardly any epimerisation to ergometrinine, with the sum of both epimers remaining constant in all seven solvents. The ergopeptides tested show variable epimerisation tendencies, and were also less stable during six weeks at 20 °C. Ergosine showed the highest degree of epimerisation (43% after 6 weeks at 20 °C). In general, the order of epimerisation promotion was methanol/dichloromethane > acetonitrile/buffer > extraction mix > stabilising solution > acetonitrile >> chloroform. Long-term storage at room temperature can only be carried out in chloroform, which showed no epimerisation for all toxins even at 20 °C and also kept the sum of R and S forms constant, which indicates no formation of aci-epimers or other degradation products. Long-term storage of ergot alkaloids in acetonitrile, the most convenient solvent with respect to HPLC analysis, should be carried out at temperatures of -20 °C or below. The constant epimer ratio of all ergot alkaloids in the extraction mixture acetonitrile/ammonium carbonate buffer (200 mg/l; 92:8, v/v) during an HPLC run (18 hours) demonstrates the stability of the toxins in this extraction mixture.

scholarly journals ACTIVITIES OF COAGULATION FACTORS IN FRESH FROZEN PLASMA AFTER LONG-TERM STORAGE

2016 ◽  
Vol 62 (4) ◽  
pp. 545-551
Author(s):  
Akihiro Fuchizaki ◽  
Jumpei Mori ◽  
Akira Iwama ◽  
Masayuki Shiba ◽  
Yu Naito ◽  
...  
Keyword(s):  
Coagulation Factors ◽  
Fresh Frozen Plasma ◽  
Long Term Storage ◽  
Fresh Frozen ◽  
Term Storage ◽  
Frozen Plasma

The Carbonate-Hardening Lime Construction Material Properties Formation during their Long-Term Storage and Use under Normal Conditions

2019 ◽  
Vol 974 ◽  
pp. 187-194 ◽  
Author(s):  
Nikolay V. Lyubomirskiy ◽  
Tamara A. Bakhtina ◽  
Alexander S. Bakhtin ◽  
Sergey I. Fedorkin
Keyword(s):  
Construction Material ◽  
Construction Materials ◽  
Materials Properties ◽  
Long Term Storage ◽  
Efficiency Assessment ◽  
The Stability ◽  
Term Storage ◽  
Long Storage ◽  
Quality Construction

This paper presents the lime binding forced carbonate-hardening materials properties formation study and determins the stability of these properties during long-term storage and use under normal conditions. The tests showed these materials stability properties over time, confirming the strength and density growth of the test samples after long storage due to the calcium hydroxide recrystallization completion into calcium carbonate processes. Also, the results of the samples carbonate hardening study under natural conditions during 18 months are presented. An efficiency assessment of forced carbonate hardening as one of the methods of recycling technogenic CO2 in order to reduce its emissions in the atmosphere, and, in the result, to obtain high-quality construction materials has been made.

scholarly journals HMGB1 concentration measurements in trauma patients: assessment of pre-analytical conditions and sample material

2019 ◽  
Vol 26 (1) ◽  
Author(s):  
William Ottestad ◽  
Ingrid N. Rognes ◽  
Erlend Skaga ◽  
Cassandra Frisvoll ◽  
Guttorm Haraldsen ◽  
...  
Keyword(s):  
Western Blot ◽  
Room Temperature ◽  
Trauma Patients ◽  
Plasma Samples ◽  
Sample Material ◽  
Limits Of Agreement ◽  
Freeze Thaw ◽  
Long Term Storage ◽  
Term Storage

Abstract Background HMGB1 is a mediator of systemic inflammation in sepsis and trauma, and a promising biomarker in many diseases. There is currently no standard operating procedure for pre-analytical handling of HMGB1 samples, despite that pre-analytical conditions account for a substantial part of the overall error rate in laboratory testing. We hypothesized that the considerable variations in reported HMGB1 concentrations and kinetics in trauma patients could be partly explained by differences in pre-analytical conditions and choice of sample material. Methods Trauma patients (n = 21) admitted to a Norwegian Level I trauma center were prospectively included. Blood was drawn in K2EDTA coated tubes and serum tubes. The effects of delayed centrifugation were evaluated in samples stored at room temperature for 15 min, 3, 6, 12, and 24 h respectively. Plasma samples subjected to long-term storage in − 80 °C and to repeated freeze/thaw cycles were compared with previously analyzed samples. HMGB1 concentrations in simultaneously acquired arterial and venous samples were also compared. HMGB1 was assessed by standard ELISA technique, additionally we investigated the suitability of western blot in both serum and plasma samples. Results Arterial HMGB1 concentrations were consistently lower than venous concentrations in simultaneously obtained samples (arterial = 0.60 x venous; 95% CI 0.30–0.90). Concentrations in plasma and serum showed a strong linear correlation, however wide limits of agreement. Storage of blood samples at room temperature prior to centrifugation resulted in an exponential increase in plasma concentrations after ≈6 h. HMGB1 concentrations were fairly stable in centrifuged plasma samples subjected to long-term storage and freeze/thaw cycles. We were not able to detect HMGB1 in either serum or plasma from our trauma patients using western blotting. Conclusions Arterial and venous HMGB1 concentrations cannot be directly compared, and concentration values in plasma and serum must be compared with caution due to wide limits of agreement. Although HMGB1 levels in clinical samples from trauma patients are fairly stable, strict adherence to a pre-analytical protocol is advisable in order to protect sample integrity. Surprisingly, we were unable to detect HMGB1 utilizing standard western blot analysis.

Synthesis Optimization of Guanidinium Dinitramide (GDN)

2020 ◽  
Vol 20 (11) ◽  
pp. 6855-6861
Author(s):  
Wooram Kim ◽  
Mijeong Park ◽  
Jong-Ki Jeon ◽  
Youngmin Jo
Keyword(s):  
Maximum Yield ◽  
Resonance Structure ◽  
Kcal Mole ◽  
Additional Advantage ◽  
Long Term Storage ◽  
Ft Ir ◽  
The Stability ◽  
Infrared Frequencies ◽  
Term Storage

Dinitramide anion [−N(NO2)2] salt composed of resonance structure is a plausible oxidizing agents, as efficient propellant. Among them, guanidinium dinitramide (GDN) is an organic compound improving the stability against moisture, as well long term storage. An additional advantage composed guanidinium ion is the reaction efficient via the decomposed by-product during pyrognostics, maximum yield of 99%. The types of GDN (GDN-I, II, III, IV, V) were synthesized using several starting material such as guanidine acetate, chloride, carbonate, nitrate and sulfate under hydrodeprivation. In this work, the intermediates formed in these processes were closely identified and their thermal properties, and chemical structure were examined. The absorption peaks by Fourier transform infrared (FT-IR) were found guanidinium infrared frequencies (3452, 3402, 3354, 3278, 1642 cm−1) and dinitramide infrared frequencies (3208, 1570, 1492, 1416, 1337, 1179, 1000 cm−1). The activation energy of GDN samples were obtained Ea = 53.26 Kcal/mole (GDN-I), 50.94 Kcal/mole (GDN-II), 52.34 Kcal/mole (GDN-III), 62.19 Kcal/mole (GDN-IV), 55.32 Kcal/mole (GDN-V) from exothermic at over 153°C.

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