Simple radioimmunoassay of cortisol in diluted samples of human plasma.

1978 ◽  
Vol 24 (9) ◽  
pp. 1468-1472 ◽  
Author(s):  
T M Connolly ◽  
P Vecsei
Keyword(s):  
Human Plasma ◽  
Plasma Proteins ◽  
Extraction Method ◽  
Plasma Cortisol ◽  
Room Temperature ◽  
Binding Proteins ◽  
Abnormal Protein ◽  
Protein Carriers ◽  
Direct Competition

Abstract We describe a simple radioimmunoassay of plasma cortisol, which can be performed in 3 h and which requires no purification, heating, or refrigeration steps. The plasma proteins are inhibited through direct competition between them and the antiserum at room temperature, at which the antiserum's affinity exceeds that of the binding proteins. Plasma, diluted with water, is incubated for 3 h at room temperature with [3H]cortisol and the antiserum. We compared results with those by the usual extraction method. The correlation between methods on evaluating normal samples with one antiserum. We compared results with those by the usual extraction method. The correlation between methods on evaluating normal samples with one antiserum was r = 0.954 (P less than 0.001), and the slope was 0.661. With three other antisera it was r = 0.922 (P less than 0.001) and slope 0.644. Plasmas with abnormal protein concentrations (i.e., from preganant women, and after corticotropin administration), tested to examine the validity of the method for routine use, and to define the role of the protein carriers, showed r = 0.859 (P less than 0.001) and slope 0.726 for the four antisera used. Additional samples, assayed with diluted standards plus stripped plasma, showed a correlation with the usual extraction method of r = 0.945 (P less than 0.001) and slope 1.026.

Patterns of Adsorption of Proteins From Human Plasma Onto Foreign Surfaces

1982 ◽  
Vol 47 (03) ◽  
pp. 285-290 ◽  
Author(s):  
S Uniyal ◽  
J L Brash
Keyword(s):  
Human Plasma ◽  
Plasma Proteins ◽  
Thromboembolic Events ◽  
Hydrophilic Surfaces ◽  
Adsorbed Proteins ◽  
Foreign Surface ◽  
Determining Factor ◽  
Hydrophilic Materials ◽  
Fibrinogen Adsorption

SummaryThe deposition of proteins on blood-contacting surfaces is known to be a determining factor in subsequent thromboembolic events. The composition of the protein layers and how they change with time are unknown. To generate information relevant to these questions, the quantities of albumin, fibrinogen and IgG adsorbed on seven surfaces from human plasma as a function of time were measured using a tracelabeling method. Materials studied include several segmented polyether-urethanes, glass, siliconized glass (SG), polystyrene (PS) and polyethylene (PE).Fibrinogen, surprisingly, was not adsorbed from plasma to any of the hydrophilic surfaces. On PE and SG adsorption passed through an early maximum (before 2 min) then declined to near zero. Only on PS was adsorption substantial and constant with time. Albumin was also not detected on the hydrophilic materials, but was adsorbed substantially on the hydrophobic surfaces. IgG was detected on all surfaces, although in relatively low surface concentrations.These results suggest: 1. that the plasma itself interacts with initially adsorbed proteins, 2. that the role of fibrinogen adsorption in foreign-surface initiated thrombosis may need to be reevaluated and 3. that since the major plasma proteins are only minimally adsorbed, trace proteins may be important in blood-material interactions.

Simple extraction method and radioimmunoassay for somatostatin in human plasma.

1981 ◽  
Vol 27 (6) ◽  
pp. 888-891 ◽  
Author(s):  
T L Peeters ◽  
Y Depraetere ◽  
G R Vantrappen
Keyword(s):  
Human Plasma ◽  
Plasma Proteins ◽  
Extraction Method ◽  
Plasma Samples ◽  
Analytical Recovery ◽  
Simple Extraction ◽  
The Mean ◽  
Radioimmunological Determination ◽  
Dilution Curves

Abstract Interference by human plasma proteins in the radioimmunological determination of somatostatin was eliminated by subjecting plasma samples to acid--ethanol precipitation. The assay was performed on the lyophilized supernate from 300 microliters of human plasma, with reagents that are commercially available. Sensitivity was 2.6 pg, corresponding to 8.7 ng/L of plasma. The intra-assay CV was 8%; the inter-assay CV was 12% for a low (30 ng/L) and 15% for a high (100 ng/L) standard. The mean analytical recovery of exogenous somatostatin from plasma was 95%, and the standard synthetic cyclic somatostatin showed parallel dilution curves with extracted plasma samples. Neither gastrin HG-17 and HG-34, pentagastrin, secretin, glucagon, vasoactive intestinal polypeptide, substance P, nor pancreatic polypeptide interfered in the assay system. Mean immunoreactive somatostatin in 20 normal fasting subjects was 31.5 (SD 15.6) ng/L and ranged from 14 to 67 ng/L.

Plasma Components which Interfere with Ristocetin-induced Platelet Aggregation

1975 ◽  
Vol 33 (03) ◽  
pp. 540-546 ◽  
Author(s):  
Robert F Baugh ◽  
James E Brown ◽  
Cecil Hougie
Keyword(s):  
Platelet Aggregation ◽  
Human Plasma ◽  
Plasma Proteins ◽  
Binding Protein ◽  
Plasma Heating ◽  
Protein S ◽  
Fold Increase ◽  
Normal Human Plasma ◽  
Preliminary Examination ◽  
Normal Human

SummaryNormal human plasma contains a component or components which interfere with ristocetin-induced platelet aggregation. Preliminary examination suggests a protein (or proteins) which binds ristocetin and competes more effectively for ristocetin than do the proteins involved in ristocetin-induced platelet aggregation. The presence of this protein in normal human plasma also prevents ristocetin-induced precipitation of plasma proteins at levels of ristocetin necessary to produce platelet aggregation (0.5–2.0 mg/ml). Serum contains an apparent two-fold increase of this component when compared with plasma. Heating serum at 56° for one hour results in an additional 2 to 4 fold increase. The presence of a ristocetin-binding protein in normal human plasma requires that this protein be saturated with ristocetin before ristocetin-induced platelet aggregation will occur. Variations in the ristocetin-binding protein(s) will cause apparent discrepancies in ristocetin-induced platelet aggregation in normal human plasmas.

Plasma Thromboplastin Component (Christmas Factor, Factor IX) Levels in Stored Human Blood and Plasma

1960 ◽  
Vol 04 (03) ◽  
pp. 376-388 ◽  
Author(s):  
J Dieter Geratz ◽  
John B. Graham
Keyword(s):  
Human Plasma ◽  
Human Blood ◽  
Whole Blood ◽  
Room Temperature ◽  
Close Agreement ◽  
Factor Ix ◽  
Deficient Patient ◽  
Glass Tubes ◽  
Disodium Hydrogen Citrate ◽  
Bank Blood

Summary1. PTC activity was assayed in 26 units of human plasma prepared from whole blood stored for 3 weeks at 4° C. The plasma had been frozen and stored at — 20° C for additional periods ranging from a few days to 4 months. High PTC activity was still present in the plasma at the end of this period, the activity averaging 95% of normal.2. The PTC activity of 19 samples of “reclaimed“ plasma stored for an additional 6 months at — 20° C decreased by an average of 23%. This decrease was statistically significant.3. Liquid plasma kept at room temperature for 5½—7½ months contained no PTC activity.4. Lyophilized plasma stored at room temperature for 6—8 years contained an average of 30% PTC activity. Lyophilized plasma stored at — 20° C for 4 years contained 68% PTC activity.5. ACD and disodium hydrogen citrate anticoagulant solutions served equally well in preserving PTC activity in whole blood stored in glass tubes over a period of 3 weeks at 4° C.6. “Reclaimed“ plasma from outdated bank blood provided effective hemostasis in two operations for the removal of 20 teeth from a severely PTC-deficient patient.7. The high PTC activity of “reclaimed“ plasma was confirmed by the close agreement between the PTC level expected in a PTC deficient patient after transfusion of such plasma and that observed.

Investigations on the Nature of Hemophilia A

1963 ◽  
Vol 09 (01) ◽  
pp. 030-052 ◽  
Author(s):  
Eberhard Mammen
Keyword(s):  
Factor Viii ◽  
Human Plasma ◽  
Barium Sulfate ◽  
Freeze Drying ◽  
Room Temperature ◽  
Hemophilia A ◽  
Normal Human Plasma ◽  
Normal Human ◽  
And Storage ◽  
Prothrombin Activation

SummaryIn this paper an inhibitor is described that is found in hemophilic plasma and serum different from any till now described inhibitor. The inhibitor only inhibits prothrombin activation in the “intrinsic clotting systems”. This inhibitor is probably not present in normal human plasma or serum. It is destroyed by ether and freeze drying, is labile to acid and storage at room temperature. It is stable upon dialysis and has not been adsorbed on barium sulfate, aluminum hydroxide or kaolin. It precipitates at 50% v/v saturation with alcohol. The nature of this inhibitor seems to be a protein or lipoprotein.Factor VIII was isolated from hemophilic plasma. The amount isolated was the same as from normal plasma and the activity properties were not different. Hemophiliacs have normal amounts of factor VIII.

Clustering-Triggered Efficient Room Temperature Phosphorescence from Nonconventional Luminophores

2019 ◽  
Author(s):  
Shuyuan Zheng ◽  
Taiping Hu ◽  
Xin Bin ◽  
Yunzhong Wang ◽  
Yuanping Yi ◽  
...  
Keyword(s):  
Room Temperature ◽  
High Efficiency ◽  
Spin Orbit Coupling ◽  
Design Rationale ◽  
Emission Mechanism ◽  
Room Temperature Phosphorescence ◽  
Electronic Interactions ◽  
Energy Gaps ◽  
Theoretical Results

Pure organic room temperature phosphorescence (RTP) and luminescence from nonconventional luminophores have gained increasing attention. However, it remains challenging to achieve efficient RTP from unorthodox luminophores, on account of the unsophisticated understanding of the emission mechanism. Here we propose a strategy to realize efficient RTP in nonconventional luminophores through incorporation of lone pairs together with clustering and effective electronic interactions. The former promotes spin-orbit coupling and boost the consequent intersystem crossing, whereas the latter narrows energy gaps and stabilizes the triplets, thus synergistically affording remarkable RTP. Experimental and theoretical results of urea and its derivatives verify the design rationale. Remarkably, RTP from thiourea solids with unprecedentedly high efficiency of up to 24.5% is obtained. Further control experiments testify the crucial role of through-space delocalization on the emission. These results would spur the future fabrication of nonconventional phosphors, and moreover should advance understanding of the underlying emission mechanism.<br>

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