In-vitro stability of human alpha-fetoprotein.

1985 ◽  
Vol 31 (10) ◽  
pp. 1692-1697 ◽  
Author(s):  
J T Wu ◽  
J A Knight
Keyword(s):  
Incubation Temperature ◽  
Enzyme Inhibitor ◽  
Alpha Fetoprotein ◽  
Proteolytic Enzyme Inhibitor ◽  
Different Temperatures ◽  
Normal Human ◽  
The Stability ◽  
Phosphate Buffered Saline ◽  
In Vitro Stability

Abstract We assessed the stability of alpha-fetoprotein (AFP) in clinical specimens in the presence and absence of serum and albumin, at different temperatures and concentrations. We find it depends on both AFP concentration and incubation temperature. Dilution of most specimens with either phosphate buffer or phosphate-buffered saline or by immunoelectrodiffusion resulted in some loss of AFP. Attempts to stabilize AFP during either sample dilution or incubation by use of albumin in concentrations up to 1 g/L did not protect it from inactivation unless normal human serum was also included. Frozen AFP solutions were less stable than solutions stored at 4 degrees C. AFP was most stable when lyophilized and stored desiccated. The AFP-inactivation curves were usually nonlinear. Apparently both polymerization and degradation occur simultaneously as AFP loses its activity. Proteolytic enzyme inhibitor and sulfhydryl reagent not only failed to protect it from inactivation, they appeared to speed it.

Ability of Inactivated Yeast Powder To Adsorb Patulin from Apple Juice

2012 ◽  
Vol 75 (3) ◽  
pp. 585-590 ◽  
Author(s):  
CAIXIA GUO ◽  
TIANLI YUE ◽  
SHAIMAA HATAB ◽  
YAHONG YUAN
Keyword(s):  
Incubation Time ◽  
Apple Juice ◽  
Incubation Temperature ◽  
Absolute Ethyl Alcohol ◽  
Initial Concentration ◽  
Different Temperatures ◽  
Yeast Powder ◽  
Commercial Yeast ◽  
The Stability ◽  
Phosphate Buffered Saline

This study aimed to investigate the adsorption of patulin from apple juice, using two types of inactivated yeast powder: laboratory-prepared yeast powder (LYP) and commercial yeast powder (CYP). The effects of incubation time, pH, incubation temperature, adsorbent amount, and initial concentration of patulin and the stability of the yeast-mycotoxin complex were assessed. The results showed that the efficiencies of the two yeast types in adsorbing patulin were similar. The ability of the powders to remove patulin increased with longer incubation times, and patulin concentration was below detectable levels with LYP and CYP at approximately 36 and 30 h, respectively. The highest removal of patulin was achieved at pH 5.0 for both powder types, and there were no significant differences in patulin decrease at different temperatures (4, 29, and 37°C). Additionally, the adsorption percentage of patulin increased significantly with the increase of absorbent amount and decrease of initial concentration of patulin. Stability of the yeast-patulin complex was assessed, and patulin was more stable when washed in phosphate-buffered saline (pH 4.0) than in absolute ethyl alcohol. These results suggest that inactivated yeast powder has potential as a novel and promising adsorbent to bind patulin effectively.

Kinetics of Various 99mTc-Sn-Pyrophosphate Compounds in the Rat

1977 ◽  
Vol 16 (04) ◽  
pp. 157-162 ◽  
Author(s):  
C. Schümichen ◽  
B. Mackenbrock ◽  
G. Hoffmann
Keyword(s):  
Normal Saline ◽  
Half Life ◽  
Compound A ◽  
Short Half Life ◽  
Low Concentrations ◽  
The Stability ◽  
Kinetics Of ◽  
In Vitro Stability

SummaryThe bone-seeking 99mTc-Sn-pyrophosphate compound (compound A) was diluted both in vitro and in vivo and proved to be unstable both in vitro and in vivo. However, stability was much better in vivo than in vitro and thus the in vitro stability of compound A after dilution in various mediums could be followed up by a consecutive evaluation of the in vivo distribution in the rat. After dilution in neutral normal saline compound A is metastable and after a short half-life it is transformed into the other 99mTc-Sn-pyrophosphate compound A is metastable and after a short half-life in bone but in the kidneys. After dilution in normal saline of low pH and in buffering solutions the stability of compound A is increased. In human plasma compound A is relatively stable but not in plasma water. When compound B is formed in a buffering solution, uptake in the kidneys and excretion in urine is lowered and blood concentration increased.It is assumed that the association of protons to compound A will increase its stability at low concentrations while that to compound B will lead to a strong protein bond in plasma. It is concluded that compound A will not be stable in vivo because of a lack of stability in the extravascular space, and that the protein bond in plasma will be a measure of its in vivo stability.

scholarly journals Effect of temperature, CO2 and O2 on motility and mobility of Anisakidae larvae

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Aiyan Guan ◽  
Inge Van Damme ◽  
Frank Devlieghere ◽  
Sarah Gabriël
Keyword(s):  
Enzymatic Digestion ◽  
Infected Fish ◽  
Effect Of Temperature ◽  
Video Recordings ◽  
Different Temperatures ◽  
Semi Solid ◽  
Zoonotic Parasites ◽  
The Impact ◽  
Phosphate Buffered Saline

AbstractAnisakidae, marine nematodes, are underrecognized fish-borne zoonotic parasites. Studies on factors that could trigger parasites to actively migrate out of the fish are very limited. The objective of this study was to assess the impact of different environmental conditions (temperature, CO2 and O2) on larval motility (in situ movement) and mobility (migration) in vitro. Larvae were collected by candling or enzymatic digestion from infected fish, identified morphologically and confirmed molecularly. Individual larvae were transferred to a semi-solid Phosphate Buffered Saline agar, and subjected to different temperatures (6 ℃, 12 ℃, 22 ℃, 37 ℃) at air conditions. Moreover, different combinations of CO2 and O2 with N2 as filler were tested, at both 6 °C and 12 °C. Video recordings of larvae were translated into scores for larval motility and mobility. Results showed that temperature had significant influence on larval movements, with the highest motility and mobility observed at 22 ℃ for Anisakis spp. larvae and 37 ℃ for Pseudoterranova spp. larvae. During the first 10 min, the median migration of Anisakis spp. larvae was 10 cm at 22 ℃, and the median migration of Pseudoterranova spp. larvae was 3 cm at 37 ℃. Larval mobility was not significantly different under the different CO2 or O2 conditions at 6 °C and 12 ℃. It was concluded that temperature significantly facilitated larval movement with the optimum temperature being different for Anisakis spp. and Pseudoterranova spp., while CO2 and O2 did not on the short term. This should be further validated in parasite-infected/spiked fish fillets.

scholarly journals A Pretargeted Imaging Strategy for EGFR Positive Colorectal Carcinoma via the Modulation of Tz-radioligand Pharmacokinetics

2020 ◽  
Author(s):  
Lin Qiu ◽  
Hui Tan ◽  
Qingyu Lin ◽  
Zhan Si ◽  
Jun Zhou ◽  
...  
Keyword(s):  
Tumor Imaging ◽  
Molecular Probes ◽  
Ideal Situation ◽  
Imaging Results ◽  
Imaging Strategy ◽  
Xenograft Mice ◽  
The Stability ◽  
In Vitro Stability

Abstract Objective: Previously, we successfully developed a pretargeted imaging strategy (Atezolizumab-TCO/99mTc-HYNIC-PEG11-Tz), which is a powerful tool for evaluating Programmed Cell Death Ligand-1 (PD-L1) expression in xenograft mice tumor models. However, the surplus unclicked 99mTc-HYNIC-PEG11-Tz is cleared somewhat sluggishly through the intestines. This is certainly not an ideal situation for imaging for colorectal cancer (CRC). In order to shift the excretion of the Tz-radioligand to the renal system, we have sought to develop a novel Tz-radioligand by adding a polypeptide linker between HYNIC and PEG11. Methods: Pretargeted molecular probes 99mTc-HYNIC-Polypeptide-PEG11-Tz and Cetuximab-TCO were synthesized. The stability of 99mTc-HYNIC-Polypeptide-PEG11-Tz was evaluated in vitro, and its blood pharmacokinetic test was performed in vivo. In vitro ligation reactivity of 99mTc-HYNIC-Polypeptide-PEG11-Tz towards Cetuximab-TCO was tested. The biodistribution and imaging of 99mTc-HYNIC-Polypeptide-PEG11-Tz was performed to observe the clear pathway of this novel Tz-radioligand. Pretargeted biodistribution of three different accumulation intervals was performed to determine the optimal pretargeted interval time. Comparison of pretargeted (Cetuximab-TCO 48 h/99mTc-HYNIC-PEG11-Tz 6 h) and (Cetuximab-TCO 48 h/99mTc-HYNIC-Polypeptide-PEG11-Tz 6 h) imagings was performed to show the effect of the two Tz-radioligands with different excretion pathway on tumor imaging. Results: 99mTc-HYNIC-Polypeptide-PEG11-Tz showed favorable in vitro stability and rapid blood clearance in mice. SEC-HPLC revealed almost complete reaction between Cetuximab-TCO and 99mTc-HYNIC-Polypeptide-PEG11-Tz in vitro, with the 8:1 Tz-to-mAb reaction providing a conversion yield of 87.83 ± 3.27%. The biodistribution and imaging of 99mTc-HYNIC-Polypeptide-PEG11-Tz demonstrated that the Tz-radioligand was cleared through kidneys. After allowing 24 h, 48 h and 72 h for accumulation of Cetuximab-TCO in HCT116 tumor, pretargeted biodistribution revealed the tumor-to-blood ratio was 0.83 ± 0.13, 1.40 ± 0.31, and 1.15 ± 0.21, respectively. Both pretargeted (Cetuximab-TCO 48 h/99mTc-HYNIC-PEG11-Tz 6 h) and (Cetuximab-TCO 48 h/99mTc-HYNIC-Polypeptide-PEG11-Tz 6 h) imaging delineated the HCT116 tumor clearly. However, pretargeted imaging strategy using Cetuximab-TCO/99mTc-HYNIC-Polypeptide-PEG11-Tz could be used for diagnosing CRC since the surplus unclicked 99mTc-HYNIC-Polypeptide-PEG11-Tz is cleared through urinary system and produces low abdominal uptake background. Conclusion: We developed a novel pretargeted imaging strategy (Cetuximab-TCO/99mTc-HYNIC-Polypeptide-PEG11-Tz) for imaging CRC since the surplus unclicked 99mTc-HYNIC-Polypeptide-PEG11-Tz produces low abdominal uptake background, which broadens the application scope of pretargeted imaging strategy.

Action of a Proteolytic Enzyme Inhibitor on Blood Coagulation in Vitro

1967 ◽  
Vol 18 (01/02) ◽  
pp. 190-197 ◽  
Author(s):  
B Blombäck ◽  
Margareta Blombäck ◽  
P Olsson
Keyword(s):  
Blood Coagulation ◽  
Proteolytic Enzyme ◽  
Enzyme Inhibitor ◽  
Factor V ◽  
Generation System ◽  
Antifibrinolytic Agents ◽  
Coagulation Activity ◽  
Serum Factors ◽  
Proteolytic Enzyme Inhibitor

SummaryThe action of the kallikrein and trypsin inhibitor, Trasylol, has been studied in a three-stage thrombin generation system. It has been found that Trasylol inhibits one or several of the early reactions of blood coagulation. The inhibition of the early stages is dependent on the concentration of inhibitor, serum factors and factor VIII. The activation of factor V by tiger snake venom is not inhibited by Trasylol. The inhibition is most probably on one or several of the reactions preceding the factor V involved step.Some other known antifibrinolytic agents have also been tested for anti-coagulation activity.

The Effects of the Spacer on Radiochemical and Biological Properties of New Radiolabeled Bombesin(7-14) Derivative

2020 ◽  
Vol 13 (2) ◽  
pp. 149-158
Author(s):  
Farzaneh Rezazadeh ◽  
Sara Karoubian ◽  
Saied Abediankenari ◽  
Nourollah Sadeghzadeh ◽  
Manouchehr Jandaghi ◽  
...  
Keyword(s):  
Radiochemical Purity ◽  
Renal Excretion ◽  
Specific Binding ◽  
Biological Properties ◽  
Radiolabeled Peptides ◽  
The Stability ◽  
Grp Receptors ◽  
In Vitro Stability ◽  
Grp Receptor

Objective: The aim of this study was to develop 99mTc-[HYNIC-X-D-Phe13]-BBN(7-14)NH2 derivatives using two different tripeptidic spacer groups (X=GGG and X=SSS) in order to improve its pharmacokinetics, in vitro stability, specific binding, and affinity. Background: Bombesin (BBN), a 14-aminoacid amphibian peptide homolog of mammalian gastrinreleasing peptide (GRP), has demonstrated the ability to bind with high affinity and specificity to GRP receptor, which is overexpressed on a variety of human cancers. Methods: Peptide conjugates labeled with 99mTc using tricine-EDDA and radiochemical purity was assessed by TLC and HPLC. The stability of radio conjugates was evaluated in the presence of saline and human serum. Affinity, internalization, and also dissociation Constant was evaluated using MDAMB- 231 and PC-3 cell line. Biodistribution study was performed in BALB/C mice. Results: Labeling yield of ˃95% was obtained. The change introduced in the BBN sequence increased plasma stability. In vitro blocking studies showed that binding and internalization of both radiolabeled peptides are mediated by their receptors on the surface of MDA-MB-231 and PC-3 cells. Biodistribution results demonstrated a rapid blood clearance, with predominantly renal excretion. Specific binding in GRP receptor-positive tissues, such as pancreas was confirmed with a blocking study. Conclusions: The introduction of the spacer sequence between chelator and BBN(7-14) led to improved bidistribution. Analog with tri-Gly spacer is the more promising radiopeptide for targeting GRP receptors than Ser conjugates. : Therefore, these analogs can be considered as a candidate for the identification of bombesin-positive tumors.

Systematic Studies on Temperature-Dependent in Vitro Stability During Storage and Smoking of the Synthetic Cannabinoid 5F-MDMB-P7AICA

2021 ◽  
Author(s):  
Nadja Walle ◽  
Adrian A Doerr ◽  
Matthias W Laschke ◽  
Michael D Menger ◽  
Markus R Meyer ◽  
...  
Keyword(s):  
Degradation Products ◽  
Parent Compound ◽  
Hydrolysis Product ◽  
Synthetic Cannabinoid ◽  
Butanoic Acid ◽  
Serum Samples ◽  
Liquid Chromatography Tandem Mass ◽  
Different Temperatures ◽  
In Vitro Stability

Abstract Metabolism studies have shown that the synthetic cannabinoid (SC) 5F-MDMB-P7AICA is predominantly degraded by ester hydrolysis to 5F-MDMB-P7AICA dimethyl butanoic acid. To investigate the stability of 5F-MDMB-P7AICA during storage for a certain period of time or smoking, in vitro stability tests were performed. Blood and serum samples were collected repeatedly during a toxicokinetic study using a pig model and were retested after a 5 and 12 months storage at different temperatures (-20 °C, 4 °C, or room temperature, RT). Analysis was performed using fully validated liquid chromatography tandem mass spectrometry methods following liquid-liquid extraction and protein precipitation. One set of samples was analyzed immediately following the experiment (WS). In the WS samples, 5F-MDMB-P7AICA and 5F-MDMB-P7AICA dimethyl butanoic acid were present in every sample collected throughout the whole experiment. Analysis of the blood and serum samples stored for 5 and 12 months at -20 °C and 4 °C revealed relatively stable concentrations of the parent substance and the dimethyl butanoic acid metabolite. Regarding the samples stored at RT, concentrations of 5F-MDMB-P7AICA decreased, whilst concentrations of the hydrolysis product increased. This change could particularly be observed in samples with a high initial concentration of the analytes. A further screening of the samples stored at RT revealed no other degradation products. In conclusion, the SC 5F-MDMB-P7AICA could be detected even after 12 months of storage at RT and therefore seems to be more stable than its isomer, 5F-ADB. Regarding the smoke condensate, beside the parent compound only trace amounts of dimethyl butanoic acid were found.

In Vitro Stability of Human Fibrinopeptide B

1979 ◽  
Vol 42 (04) ◽  
pp. 1316-1323
Author(s):  
G D Qureshi ◽  
William C Vennart
Keyword(s):  
Molar Ratio ◽  
Temperature Dependent ◽  
Carboxypeptidase B ◽  
Enzyme Substrate ◽  
Substrate Molar Ratio ◽  
Normal Urine ◽  
The Stability ◽  
In Vitro Stability ◽  
Plasma Ultrafiltrate

SummaryIn anticipation of a future clinical application of plasma fibrinopeptide B (FPB) measurement, we studied the stability of FPB in an ultrafiltrate of normal plasma, normal urine and alkaline buffer by measuring the immunoreactivity of the peptide by FPB radioimmunoassay using anti FPB serum (R-29). FPB was unstable in an ultrafiltrate of plasma and urine and demonstrated a temperature dependent loss of activity. In plasma ultrafiltrate the loss of immunoreactivity was not significant during the first 24 hours, however, 92% of the peptide activity was lost at the end of seven days at 25° C and 37° C. The rate of FPB degradation in urine was comparable. The peptide was stable in an alkaline buffer (pH 8.5) at temperatures ranging from �10° C to 37° C or in plasma ultrafiltrate or urine when incubated at �10° C. Treatment with carboxypeptidase B or leucine aminopep- tidase for two hours at 37° C (enzyme/substrate molar ratio of up to 1:100) did not cause a loss of FPB immunoreactivity. EDTA (1.0 mM) and Trasylol (500 units/ml) completely stabilized the peptide in a plasma ultrafiltrate.

scholarly journals Development of Topical Niosomal Gel of Benzoyl Peroxide

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Jigar Vyas ◽  
Puja Vyas ◽  
Dhaval Raval ◽  
Paresh Paghdar
Keyword(s):  
Benzoyl Peroxide ◽  
In Vitro Release ◽  
Skin Penetration ◽  
Topical Gel ◽  
Different Temperatures ◽  
Skin Redness ◽  
The Stability ◽  
Niosomal Gel ◽  
Vitro Release

Benzoyl peroxide is macrolide antibiotic used commonly for the treatment of acne either alone or in combination. But it suffers from side effects like skin redness, irritation, itching, and edema. Niosomes, a nonionic surfactant vesicular formulation, have been explored extensively for topical application to enhance skin penetration as well as to improve skin retention of drugs. In the present study, Benzoyl peroxide was entrapped into niosomes by thin film hydration technique, and various process parameters were optimized by partial factorial design. The optimized niosomal formulation was incorporated into HPMC K15 gel and extensively characterized for percentage drug entrapment (PDE) and in vitro release performance. The stability of above formulation was studied at different temperatures. The present study demonstrated prolongation of drug release, increased drug retention into skin, and improved permeation across the skin after encapsulation of benzoyl peroxide into niosomal topical gel.

scholarly journals Cardiolipin Stabilizes and Increases Catalytic Efficiency of Carnitine Palmitoyltransferase II and Its Variants S113L, P50H, and Y479F

2021 ◽  
Vol 22 (9) ◽  
pp. 4831
Author(s):  
Beate Meinhardt ◽  
Leila Motlagh Scholle ◽  
Franziska Seifert ◽  
Martina Anwand ◽  
Markus Pietzsch ◽  
...  
Keyword(s):  
Catalytic Efficiency ◽  
Carnitine Palmitoyltransferase ◽  
Differential Scanning Fluorimetry ◽  
Different Temperatures ◽  
Functional Consequences ◽  
The Stability ◽  
Carnitine Palmitoyltransferase Ii ◽  
The Impact

Muscle carnitine palmitoyltransferase II (CPT II) deficiency is associated with various mutations in CPT2 gene. In the present study, the impact of the two CPT II variants P50H and Y479F were characterized in terms of stability and activity in vitro in comparison to wildtype (WT) and the well investigated variant S113L. While the initial enzyme activity of all variants showed wild-type-like behavior, the activity half-lives of the variants at different temperatures were severely reduced. This finding was validated by the investigation of thermostability of the enzymes using nano differential scanning fluorimetry (nanoDSF). Further, it was studied whether the protein stabilizing diphosphatidylglycerol cardiolipin (CL) has an effect on the variants. CL indeed had a positive effect on the stability. This effect was strongest for WT and least pronounced for variant P50H. Additionally, CL improved the catalytic efficiency for CPT II WT and the investigated variants by twofold when carnitine was the varied substrate due to a decrease in KM. However, there was no influence detected for the variation of substrate palmitoyl-CoA. The functional consequences of the stabilization by CL in vivo remain open.

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