A STUDY OF THE STORAGE STABILITY OF VIRAL ANTISERA

1965 ◽  
Vol 11 (3) ◽  
pp. 503-507 ◽  
Author(s):  
F. P. Nagler ◽  
J. R. Polley
Keyword(s):  
Antibody Titer ◽  
Diagnostic Tests ◽  
Storage Stability ◽  
High Titer ◽  
Bovine Albumin ◽  
The Stability

Antisera prepared against certain viruses contained antibodies of particularly high titer and it seemed desirable to dilute them before distribution for use in diagnostic tests. A study was made of the stability of viral antisera stored undiluted and diluted under various conditions. It was found that, in general, the sera could be diluted, lyophilized, and stored, even at 37 °C for a year, with little or no loss of antibody titer if the diluent was 5% peptone or 10% bovine albumin rather than saline.

scholarly journals The influence of sugar–protein complexes on the thermostability of C-reactive protein (CRP)

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Andreea Lorena Mateescu ◽  
Nicolae-Bogdan Mincu ◽  
Silvana Vasilca ◽  
Roxana Apetrei ◽  
Diana Stan ◽  
...  
Keyword(s):  
Diagnostic Tests ◽  
Protein Complexes ◽  
C Reactive Protein ◽  
Time Resolved Fluorescence ◽  
Time Resolved ◽  
Reactive Protein ◽  
In Vitro Diagnostic ◽  
The Stability ◽  
Positive Controls

AbstractThe purpose of the present study was to evaluate de influence of protein–sugar complexation on the stability and functionality of C-reactive protein, after exposure to constant high temperatures, in order to develop highly stable positive controls for in-vitro diagnostic tests. C-reactive protein is a plasmatic protein used as a biomarker for the diagnosis of a series of health problems such as ulcerative colitis, cardiovascular diseases, metabolic syndrome, due to its essential role in the evolution of chronic inflammation. The sugar–protein interaction was investigated using steady state and time resolved fluorescence. The results revealed that there are more than two classes of tryptophan, with different degree of accessibility for the quencher molecule. Our study also revealed that sugar–protein complexes have superior thermostability, especially after gamma irradiation at 2 kGy, the protein being stable and functional even after 22 days exposure to 40 °C.

scholarly journals Spectral Characteristic, Storage Stability and Antioxidant Properties of Anthocyanin Extracts from Flowers of Butterfly Pea (Clitoria Ternatea L.)

Molecules ◽  
2021 ◽  
Vol 26 (22) ◽  
pp. 7000
Author(s):  
Xueying Fu ◽  
Qiang Wu ◽  
Jian Wang ◽  
Yanli Chen ◽  
Guopeng Zhu ◽  
...  
Keyword(s):  
Food Processing ◽  
Storage Stability ◽  
Ph Value ◽  
Antioxidant Properties ◽  
Radical Scavenging ◽  
Nutritional Values ◽  
Clitoria Ternatea ◽  
Alkaline Conditions ◽  
Butterfly Pea ◽  
The Stability

Anthocyanins from flowers of the butterfly pea (Clitoria ternatea L.) are promising edible blue food colorants. Food processing often faces extreme pHs and temperatures, which greatly affects the color and nutritional values of anthocyanins. This study explored the color, spectra, storage stability, and antioxidant properties of C. ternatea anthocyanin extract (CTAE) at different pHs. The color and absorption spectra of CTAEs at a pH of 0.5–13 were shown, with their underlying structures analyzed. Then, the storage stability of CTAEs were explored under a combination of pHs and temperatures. The stability of CTAE declines with the increase in temperature, and it can be stored stably for months at 4 °C. CTAEs also bear much resistance to acidic and alkaline conditions but exhibit higher thermal stability at pH 7 (blue) than at pH 0.5 (magenta) or pH 10 (blue-green), which is a great advantage in food making. Antioxidant abilities for flower extracts from the butterfly pea were high at pH 4–7, as assessed by DPPH free radical scavenging assays, and decreased sharply when the pH value exceeded 7. The above results provide a theoretical basis for the application of butterfly pea flowers and imply their great prospect in the food industry.

scholarly journals Investigation and Validation of Detection of Storage Stability of Difenoconazole Residue in Mango

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Fangfang Zhao ◽  
Jingkun Liu ◽  
Bingjun Han ◽  
Jinhui Luo
Keyword(s):  
Food Safety ◽  
Pesticide Residue ◽  
Storage Stability ◽  
Sample Solution ◽  
Sample Storage ◽  
Fruit Samples ◽  
Different Temperatures ◽  
The Stability ◽  
Food Safety And Quality ◽  
Accuracy And Stability

To investigate the stability of the pesticide residue in storage samples is a part of detection, which is also an improvement to the accuracy of analytical results. In this work, the UPLC-MS/MS method with perfect accuracy and stability was established for determining residues of difenoconazole in mango. The stability of the residue under different temperatures (4°C and −20°C) and media (fruit samples and pretreated sample solution) was investigated. At 0.1 mg/kg, the residue degraded in 6 months by 12% when at −20°C, while in a week by only 12.2% at 4°C. However, when pretreated and preserved in the solution, the residue remained more than 90% for 6–8 weeks. The results indicated that the main causes of degradation are biochemical factors, and the factors are affected by temperature. The findings also provided appropriate conditions for sample storage. This investigation promotes the accuracy in detection and hence guarantees food safety and quality.

Use of purified lyophilized human lactate dehydrogenase isoenzyme 5 in a study of measuring lactate dehydrogenase activity.

1989 ◽  
Vol 35 (8) ◽  
pp. 1774-1776 ◽  
Author(s):  
D A Smith ◽  
G C Moses ◽  
A R Henderson
Keyword(s):  
Lactate Dehydrogenase ◽  
Half Life ◽  
Specific Activity ◽  
Lactate Dehydrogenase Activity ◽  
Bovine Albumin ◽  
First Order ◽  
First Order Kinetics ◽  
The Stability ◽  
Lactate Dehydrogenase Isoenzymes ◽  
Excellent Stability

Abstract We examined the stability of human lactate dehydrogenase (EC 1.1.1.27) isoenzyme 5--purified to a specific activity of about 400 kU/g--when lyophilized in a buffered, stabilized matrix of bovine albumin. This isoenzyme was prepared with a final activity of about 500 U/L and stored at -20, 4, 20, 37, and 56 degrees C for as long as six months. This isoenzyme decayed with approximate first-order kinetics, with an estimated half-life at -20 degrees C of about 475 years. Stability of reconstituted samples stored at 20 or 4 degrees C was poor, suggesting that the reconstituted material should be used without delay; material stored at -20 degrees C showed excellent stability for 15 days. We propose that such preparations might be further investigated as standards for use in electrophoresis of lactate dehydrogenase isoenzymes.

Decreased storage stability of creatine kinase in a cardiac reperfusion solution

1990 ◽  
Vol 36 (5) ◽  
pp. 778-780 ◽  
Author(s):  
G Dunphy ◽  
D Ely
Keyword(s):  
Creatine Kinase ◽  
Low Temperatures ◽  
Storage Stability ◽  
Frozen Storage ◽  
Cellular Damage ◽  
Prolonged Storage ◽  
Cold Preservation ◽  
Rat Hearts ◽  
The Stability ◽  
Storage Temperatures

Abstract Creatine kinase (CK; EC 2.7.3.2) has been used as an indicator of myocardial cellular damage. In this study we used a Krebs-Henseleit (KH) solution to reperfuse isolated rat hearts after 24 h of cold preservation and collected the KH reperfusate for assay of CK to assess cellular damage. We wanted to determine the stability of CK in the KH solution at different cold-storage temperatures and albumin concentrations. CK activity (mean +/- SEM) after one week of refrigeration (5 degrees C) was 93% +/- 1% of control values, whereas CK activity in nitrogen-frozen (-200 degrees C) samples was only 1.6% +/- 1% of control values, and that in samples frozen at moderately low temperatures (-10 degrees C) was 63% +/- 1% of control values. To enhance stability, we added albumin at several concentrations (49, 25, 12, and 6 g/L) to reperfusion collections in which CK had been previously determined. Specimens were frozen (-10 degrees C), then re-analyzed for CK weekly for three weeks. CK activity was maintained (100% +/- 5%) only in samples containing 25 g/L or more albumin. These data suggest that refrigeration (5 degrees C) for one week maintains normal CK activity in KH solution; however, if prolonged storage is necessary, a stabilizer such as albumin (greater than or equal to 25 g/L) will maintain analyte stability in frozen storage (-10 degrees C) for at least three weeks.

scholarly journals Black Bean Anthocyanin-Rich Extract from Supercritical and Pressurized Extraction Increased In Vitro Antidiabetic Potential, While Having Similar Storage Stability

Foods ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 655 ◽  
Author(s):  
Ming Hsieh-Lo ◽  
Gustavo Castillo-Herrera ◽  
Luis Mojica
Keyword(s):  
Phenolic Compounds ◽  
Storage Stability ◽  
Ultra Performance Liquid Chromatography ◽  
Syringic Acid ◽  
Total Phenolic ◽  
Black Bean ◽  
Flight Mass Spectrometry ◽  
Biological Potential ◽  
The Stability

Black bean is a source of anthocyanins and other phenolic compounds that are associated with health benefits. This work aimed to optimize the extraction and determine the stability and biological potential of black bean anthocyanin-rich extracts recovered by supercritical fluid extraction (SFE) and pressurized liquid extraction (PLE). The highest concentration of anthocyanins and total phenolic compounds were recovered with SFE using 300 bar, 60 °C and co-solvent ethanol/distilled water (50/50, v/v). Eleven non-colored phenolic compounds were identified in SFE extract using Ultra performance liquid chromatography - Electrospray ionization–Quadrupole -Time of flight - Mass spectrometry (UPLC-ESI-QToF-MS/MS). Myricetin, syringic acid, rutin hydrate and chlorogenic acid presented the highest relative area among identified compounds. Compared to leaching extraction, SFE extracts showed a similar storage stability at 4, 25 and 32 °C (p < 0.05), but with a higher antioxidant potential (2,2-diphenyl-1-picryl-hydrazil (DPPH) IC50: 0.078 ± 0.01; 2,2’-azino-bis(3-ethylbenzothiazoline)-6-sulfonic acid (ABTS) IC50: 0.161 ± 0.03) and antidiabetic potential (α-amylase IC50: 124.76 ± 12.97; α-glucosidase IC50: 31.30 ± 0.84; dipeptidyl peptidase-IV IC50: 0.195 ± 0.01). SFE extraction is an efficient method to obtain anthocyanins and other phenolic compounds with exceptional biological potential.

Reduction of Anti-FVIII Inhibitor Titers in Hemophilic Mice Infused with Syngeneic Apoptotic Cells Expressing a Human FVIII Transgene.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 216-216
Author(s):  
Rui-Jun Su ◽  
Laura Stewart ◽  
Steven W. Pipe ◽  
Neil C. Josephson
Keyword(s):  
Cell Proliferation ◽  
T Cell ◽  
Antibody Titer ◽  
Immune Tolerance ◽  
Hemophilia A ◽  
Apoptotic Cell ◽  
High Titer ◽  
T Cell Proliferation ◽  
Apoptotic Cells ◽  
Proliferation Assays

Abstract Approximately 30% of patients with severe hemophilia A develop neutralizing antibodies (inhibitors) to factor VIII (FVIII). Frequently, the inhibitors that develop are persistent and of sufficiently high titer that infusion of FVIII concentrates are ineffective for the control of bleeding episodes. At present the only method for elimination of high titer inhibitors is Immune Tolerance Induction (ITI) by exposing patients to repeated FVIII doses. However, it is extremely expensive and takes many months to complete. There is a need to develop quicker, cheaper, and more reliable protocols for inducing tolerance in patients with high titer FVIII inhibitors, and of preventing their occurrence in patients at high risk. In a non-inflammatory environment, autologous apoptotic cells are processed by immature, non-activated dendritic cells (DCs) capable of initiating peripheral immune tolerance through the stimulation of different classes of regulatory T cells. Furthermore, it has been demonstrated that antigen specific tolerance can be induced by delivery of a foreign protein within dying syngeneic cells (Liu et al, J Exp Med196: 1091, 2002). We hypothesize that immune tolerance to FVIII can be induced by the infusion of apoptotic autologous cells engineered to carry a FVIII expression vector. We generated a fibroblast cell line from a tail snip of a 129Sv-FVIIIKO mouse and transduced the cells with a foamy virus vector expressing a B-domain deleted human FVIII construct. Expression of human FVIII was detected by ELISA in the supernatant of cultured transduced fibroblasts. These transduced cells were induced to apoptosis by serum starvation for 24–30 hr prior to infusion into 129Sv-FVIIIKO mice. Treated mice received two weekly doses of 1x107 serum starved transduced fibroblasts. Control mice were infused with culture media alone. Ten days after the final infusion, experimental and control mice were challenged with 4 weekly intravenous doses of 0.2 μg albumin free recombinant human FVIII (ADVATE). Ten days after the final dose of ADVATE blood samples were collected and evaluated for inhibitor titer by Bethesda assay and for total anti-FVIII antibody titer by ELISA. Three weeks later, T cell proliferation assays were performed on samples from mice in each group. The mice that received apoptotic cells had lower inhibitor titers than controls, 156.7 ± 82.7 BU/ml (n = 6) versus 331.3 ± 183.9 BU/ml (n = 11) (p = 0.017, Welch’s t-test). However, total antibody titer levels determined by ELISA were not significantly different between the two groups. T-cell proliferation assays also showed a reduced T cell response in the apoptotic cell treated mice with a stimulation index that was half that seen in the controls. Our data show that inhibitor titers and T cell responses in hemophilia A mice challenged by albumin free recombinant FVIIII can be reduced by the prior infusion of apoptotic syngeneic cells transduced with a human FVIII expressing vector. Future work will focus on optimizing apoptotic cell delivery protocols to maximally suppress the immune response to FVIII and on elucidating the mechanisms responsible for our findings. Figure Figure

scholarly journals Application of Chimeric Feline Foamy Virus-Based Retroviral Vectors for the Induction of Antiviral Immunity in Cats

2003 ◽  
Vol 77 (14) ◽  
pp. 7830-7842 ◽  
Author(s):  
Astrid Schwantes ◽  
Uwe Truyen ◽  
Joachim Weikel ◽  
Christian Weiss ◽  
Martin Löchelt
Keyword(s):  
Cell Cultures ◽  
High Titer ◽  
Foamy Virus ◽  
Retroviral Vectors ◽  
Partial Protection ◽  
Humoral Immune ◽  
The Stability ◽  
Bet Protein ◽  
Hybrid Fusion

ABSTRACT In order to define the potential and applicability of replication-competent foamy virus-based vaccine vectors, recombinant feline foamy virus (FFV) vectors encoding defined segments of the feline calicivirus (FCV) capsid protein E domain were constructed. In cell cultures, these FFV-FCV vectors efficiently transduced and expressed a hybrid fusion protein consisting of the essential FFV Bet protein and the attached FCV E domains. The stability of the vectors in vitro was inversely correlated to the size of the heterologous insert. The deletion of a part of the FFV U3 sequence in these FFV-FCV vectors did not interfere with replication and titer in cell cultures but increased the genetic stability of the hybrid vectors. Selected chimeric vectors were injected into immunocompetent cats and persisted in the transduced host concomitant with a strong and specific humoral immune response against vector components. In a substantial number of cats, antibodies directed against the FCV E domain were induced by the FFV-FCV vectors, but no FCV-neutralizing activities were detectable in vitro. When the vaccinated cats were challenged with a high-titer FCV dose, sterile immunity was not induced by any of the hybrid FFV-FCV vectors. However, the FFV-FCV vector with a truncated U3 region of the long terminal repeat promoter significantly reduced the duration of FCV shedding after challenge and suppressed the appearance of FCV-specific ulcers. Possible mechanisms contributing to the partial protection will be discussed.

STUDIES ON BACTERIAL AGGLUTINATION BY USE OF THE ANTIGLOBULIN (COOMBS) TECHNIQUE

1956 ◽  
Vol 2 (7) ◽  
pp. 657-664 ◽  
Author(s):  
Arthur C. Ford ◽  
Ralph J. DeFalco
Keyword(s):  
Antibody Titer ◽  
Human Albumin ◽  
Bacterial Cells ◽  
Specific Test ◽  
Bovine Albumin ◽  
Cell Antigen ◽  
Antiglobulin Test ◽  
Bacterial Agglutination

The Coombs antiglobulin test has been successfully applied to bacterial cells in agglutination reactions. The test is a test for attached antibody globulin. Titers obtained by this method are shown to be from one to three tubes higher than those obtained by routine agglutination tests. Polyvinylpyrrolidone (PVP), bovine albumin, and human albumin have also been shown to hasten and strengthen bacterial agglutinations. The incomplete albumin reacting antibody titer of antisera seems to be higher than that of the saline reacting, or complete antibodies. The Coombs reaction is a specific test for antibody globulin attached to sensitized cells. There is no reaction where there is no combination between antibody globulin and the cell antigen, as shown by heterologous tests.

scholarly journals Copan eNAT Transport System to Address Challenges in COVID-19 Diagnostics in Regions with Limited Testing Access

2021 ◽  
Author(s):  
Melissa Richard-Greenblatt ◽  
Courtney E. Comar ◽  
Laurence Flevaud ◽  
Marina Berti ◽  
Rebecca M. Harris ◽  
...  
Keyword(s):  
Transport System ◽  
Rural Areas ◽  
Storage Temperature ◽  
Point Of Care ◽  
High Titer ◽  
Healthcare Access ◽  
Cold Chain ◽  
Specimen Handling ◽  
Outreach Services ◽  
The Stability

Community-based healthcare clinics and hospital outreach services have the potential to expand coronavirus disease 2019 (COVID-19) diagnostics to rural areas. However, reduced specimen stability during extended transport, the absence of cold chain to centralized laboratories, and biosafety concerns surrounding specimen handling has limited this expansion. In the following study, we evaluated eNAT (Copan Italia, Brescia, Italy) as an alternative transport system to address the biosafety and stability challenges associated with expanding COVID-19 diagnostics to rural and remote regions. In this study, we demonstrated that high titer severe acute respiratory virus syndrome coronavirus 2 (SARS-CoV-2) lysate placed into eNAT medium cannot be propagated in cell culture, supporting viral inactivation. To account for off-site testing in these settings, we assessed the stability of contrived nasopharyngeal (NP) specimens stored for up to 14 days in various transport medium (eNAT, eSwab, viral transport media [VTM], saline and phosphate-buffered saline [PBS]) at 4°C, 22-25°C, and 35°C. Molecular detection of SARS-CoV-2 was unaffected by sample storage temperature over the 2 weeks when stored in eNAT or PBS (change in cycle threshold [ΔCT] ≤ 1). In contrast, variable stability was observed across test conditions for other transport media. As eNAT can inactivate SARS-CoV-2, it may support COVID-19 diagnostics at the point-of-care (POC). Evaluation of compatibility of eNAT with Cepheid Xpert Xpress SARS-CoV-2 assay demonstrated equivalent diagnostic accuracy and sensitivity compared to VTM. Taken together, these findings suggest that the implementation of eNAT as a collection device has the potential to expand COVID-19 testing to areas with limited healthcare access.

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