Equilibrium Dialysis in a Stainless Steel Chamber: Measurement of the Free Plasma Fraction of Cyclosporin

2000 ◽  
Vol 6 (10) ◽  
pp. 447-450
Author(s):  
F. Callejón ◽  
J.A. Durán ◽  
J.A. Abadín ◽  
Keyword(s):  
Stainless Steel ◽  
Equilibrium Dialysis ◽  
Plasma Fraction ◽  
Free Plasma

Relationship between plasma and salivary melatonin and cortisol investigated by LC-MS/MS

2017 ◽  
Vol 55 (9) ◽  
Author(s):  
Martijn van Faassen ◽  
Rainer Bischoff ◽  
Ido P. Kema
Keyword(s):  
Mass Spectrometry ◽  
Equilibrium Dialysis ◽  
Added Value ◽  
The Novel ◽  
Plasma Melatonin ◽  
Disease States ◽  
Validation Criteria ◽  
Significant Difference ◽  
Salivary Melatonin ◽  
Free Plasma

AbstractBackground:Disturbance of the circadian rhythm has been associated with disease states, such as metabolic disorders, depression and cancer. Quantification of the circadian markers such as melatonin and cortisol critically depend on reliable and reproducible analytical methods. Previously, melatonin and cortisol were primarily analyzed separately, mainly using immunoassays.Methods:Here we describe the validation and application of a high-throughput liquid chromatography in combination with mass spectrometry (LC-MS/MS) method for the combined analysis of melatonin and cortisol in plasma and saliva. The LC-MS/MS method was validated according to international validation guidelines. We used this method to analyze total plasma, free plasma (as obtained by equilibrium dialysis) and saliva melatonin and cortisol in healthy adults.Results:Validation results for plasma and saliva melatonin and cortisol were well within the international validation criteria. We observed no difference between saliva collected by passive drooling or Salivette. Moreover, we noted a significant difference in saliva vs. free plasma melatonin. We observed on average 36% (95% CI: 4%–60%) higher salivary melatonin levels in comparison to free plasma melatonin, suggestive of local production of melatonin in the salivary glands.Conclusions:The novel outcome of this study is probably due to the high precision of our LC-MS/MS assay. These outcomes illustrate the added value of accurate and sensitive mass spectrometry based methods for the quantification of neuroendocrine biomarkers.

scholarly journals Protein Binding of Rifapentine and Its 25-Desacetyl Metabolite in Patients with Pulmonary Tuberculosis

2014 ◽  
Vol 58 (8) ◽  
pp. 4904-4910 ◽  
Author(s):  
Eric F. Egelund ◽  
Marc Weiner ◽  
Rajendra P. Singh ◽  
Thomas J. Prihoda ◽  
Jonathon A. L. Gelfond ◽  
...  
Keyword(s):  
Pulmonary Tuberculosis ◽  
Protein Binding ◽  
Clinical Outcomes ◽  
Exploratory Study ◽  
Active Fraction ◽  
Black Race ◽  
Data Support ◽  
Plasma Fraction ◽  
African Patients ◽  
Free Plasma

ABSTRACTRifapentine is highly protein bound in blood, but the free, unbound drug is the microbiologically active fraction. In this exploratory study, we characterized the free plasma fraction of rifapentine in 41 patients with tuberculosis. We found a lower total rifapentine concentration but significantly higher free rifapentine levels in African patients of black race compared to non-Africans. These data support larger pharmacokinetic/pharmacodynamic studies to confirm these findings and assess free rifapentine in relation to microbiological and clinical outcomes.

Fate of Thrombin and Thrombin-Antithrombin-III Complex Adsorbed to a Heparinized Biomaterial: Analysis of the Enzyme-Inhibitor Complexes Displaced by Plasma

1983 ◽  
Vol 50 (04) ◽  
pp. 873-877 ◽  
Author(s):  
Mark W C Hatton ◽  
Gordon Rollason ◽  
Michael V Sefton
Keyword(s):  
Human Plasma ◽  
Antithrombin Iii ◽  
Enzyme Inhibitor ◽  
Gel Filtration ◽  
Similar Rate ◽  
Subsequent Treatment ◽  
Enzyme Inactivation ◽  
Plasma Fraction ◽  
Thrombin Antithrombin Iii Complex ◽  
Free Plasma

SummaryHeparin covalently-linked to polyvinyl alcohol (PVA) is a biomaterial which is of potential value as a non-thrombogenic coating. 125I-labelled thrombin adsorbed to heparin-PVA beads was not dislodged by phosphate-buffered saline, pH 7.4, although radioactivity was progressively displaced from the adsorbent by fibrinogen-free human plasma. Analysis by gel filtration and affinity chromatography showed that the released radioactivity was distributed between (thrombin-antithrombin-III) complex (approx. 70%) and, probably, (thrombin-α-2-macroglobulin) complex (approx. 30%). Less efficient thrombin displacement was obtained by either bovine serum albumin (5% w/v) or antithrombin-III-free human plasma: in the latter case, the dislodged enzyme was presumably associated with α-2-macroglobulin. Purified α-2-macroglobulin did not displace thrombin from heparin-PVA. The quantity of thrombin displaced by an α- 2-macroglobulin-free plasma fraction compared well with fibrinogen-free plasma: The eluted enzyme was largely associated with antithrombin-III. Purified antithrombin-III did not displace thrombin from heparin-PVA despite causing >70% inactivation of the bound enzyme. Subsequent treatment with fibrinogen-free plasma dislodged (thrombin-antithrombin-III) at a similar rate to that of bound thrombin. We conclude that plasma contains a component(s) which displaces (thrombin-antithrombin-III) complex from immobilised heparin: presumably this leaves the heparin sites free for further use in enzyme inactivation.

AGE RELATED CHANGES IN FREE PLASMA TESTOSTERONE, DIHYDROTESTOSTERONE AND OESTRADIOL

1975 ◽  
Vol 80 (1) ◽  
pp. 171-178 ◽  
Author(s):  
Karl M. Pirke ◽  
Peter Doerr
Keyword(s):  
Healthy Adult ◽  
Equilibrium Dialysis ◽  
Plasma Testosterone ◽  
Age Group ◽  
Adult Males ◽  
Age Related ◽  
Group I ◽  
Group Ii ◽  
Free Plasma ◽  
Age Related Changes

ABSTRACT The age related changes on free plasma testosterone (T), dihydrotestosterone (DHT) and oestradiol (Oe2) were determined in 82 healthy adult males. Forty-six subjects were between 22 and 61 years of age (group I), 36 between 67 and 93 years (group II). The percentage of free, non protein bound hormone was determined by equilibrium dialysis of undiluted plasma against isotonic phosphate buffer at 37°C. Total hormone concentrations were measured by radioimmunoassay. The percentage of free T was 2.24 % (median), 1.65–3.42 (95 percentiles) in group I and 1.65 % (1.24–2.26) in group II. The percentage of free DHT decreased from 1.17 % (0.80–2.03) in group I to 0.83% (0.52–1.55) in group II. The decrease in % free Oe2 was only very small: group I = 2.49% (2.13–2.96), ad group II = 2.31% (1.95–3.17). The fall in free T by 43.3% from 12.2 ng/100 ml (6.74–25.0) in group I to 6.90 ng/ml (3.57–10.6) in group II was twice as high as that of total T, which decreased on an average by 20.6%. Free DHT decreased by 25.8 %: group I = 578 pg/100 ml (266–987), group II = 429 pg/100 ml (168–723), while total DHT was not significantly different between the two groups (–1.9%). Free Oe2 was increased in old age: group I = 42.4 pg/100 ml (26.0–69.4), group II = 55.7 pg/100 ml (35.8–118.9). The increase in free Oe2 by 31.4% was almost as high as that of the total Oe2 (46.9%).

Factors Affecting the Free Plasma Fraction of Phenytoin in Patients with Epilepsy

1998 ◽  
Vol 15 (2) ◽  
pp. 153-157 ◽  
Author(s):  
Manuel Carlos Jim??nez ◽  
Jos?? Antonio Dur??n ◽  
Jos?? Antonio Abad ??n
Keyword(s):  
Factors Affecting ◽  
Plasma Fraction ◽  
Patients With Epilepsy ◽  
Free Plasma

Free Plasma Fraction of Valproic Acid in Epileptic Patients

1993 ◽  
Vol 5 (2) ◽  
pp. 108-113
Author(s):  
J. A. Durán ◽  
J. A. Abadín ◽  
A. Sánchez ◽  
J. S. Serrano
Keyword(s):  
Valproic Acid ◽  
Plasma Fraction ◽  
Epileptic Patients ◽  
Free Plasma

scholarly journals B Cells and Platelets Harbor Prion Infectivity in the Blood of Deer Infected with Chronic Wasting Disease

2010 ◽  
Vol 84 (10) ◽  
pp. 5097-5107 ◽  
Author(s):  
Candace K. Mathiason ◽  
Jeanette Hayes-Klug ◽  
Sheila A. Hays ◽  
Jenny Powers ◽  
David A. Osborn ◽  
...  
Keyword(s):  
B Cells ◽  
Chronic Wasting Disease ◽  
Transmissible Spongiform Encephalopathy ◽  
Cell Phenotype ◽  
Spongiform Encephalopathy ◽  
Wasting Disease ◽  
Prion Infection ◽  
Plasma Fraction ◽  
Free Plasma

ABSTRACT Substantial evidence for prion transmission via blood transfusion exists for many transmissible spongiform encephalopathy (TSE) diseases. Determining which cell phenotype(s) is responsible for trafficking infectivity has important implications for our understanding of the dissemination of prions, as well as their detection and elimination from blood products. We used bioassay studies of native white-tailed deer and transgenic cervidized mice to determine (i) if chronic wasting disease (CWD) blood infectivity is associated with the cellular versus the cell-free/plasma fraction of blood and (ii) in particular if B-cell (MAb 2-104+), platelet (CD41/61+), or CD14+ monocyte blood cell phenotypes harbor infectious prions. All four deer transfused with the blood mononuclear cell fraction from CWD+ donor deer became PrPCWD positive by 19 months postinoculation, whereas none of the four deer inoculated with cell-free plasma from the same source developed prion infection. All four of the deer injected with B cells and three of four deer receiving platelets from CWD+ donor deer became PrPCWD positive in as little as 6 months postinoculation, whereas none of the four deer receiving blood CD14+ monocytes developed evidence of CWD infection (immunohistochemistry and Western blot analysis) after 19 months of observation. Results of the Tg(CerPrP) mouse bioassays mirrored those of the native cervid host. These results indicate that CWD blood infectivity is cell associated and suggest a significant role for B cells and platelets in trafficking CWD infectivity in vivo and support earlier tissue-based studies associating putative follicular B cells with PrPCWD. Localization of CWD infectivity with leukocyte subpopulations may aid in enhancing the sensitivity of blood-based diagnostic assays for CWD and other TSEs.

NiAl precipitation in Fe-12w/o Cr-5w/o Ni-4w/o Al

1983 ◽  
Vol 41 ◽  
pp. 202-203
Author(s):  
L.E. Murr ◽  
J.S. Dunning ◽  
S. Shankar
Keyword(s):  
Solid Solution ◽  
Stainless Steel ◽  
Stainless Steels ◽  
Alloy Composition ◽  
Chromium Content ◽  
Scale Up ◽  
Optical Metallography ◽  
Property Evaluation ◽  
310 Stainless Steel ◽  
Microstructural Studies

Aluminum additions to conventional 18Cr-8Ni austenitic stainless steel compositions impart excellent resistance to high sulfur environments. However, problems are typically encountered with aluminum additions above about 1% due to embrittlement caused by aluminum in solid solution and the precipitation of NiAl. Consequently, little use has been made of aluminum alloy additions to stainless steels for use in sulfur or H2S environments in the chemical industry, energy conversion or generation, and mineral processing, for example.A research program at the Albany Research Center has concentrated on the development of a wrought alloy composition with as low a chromium content as possible, with the idea of developing a low-chromium substitute for 310 stainless steel (25Cr-20Ni) which is often used in high-sulfur environments. On the basis of workability and microstructural studies involving optical metallography on 100g button ingots soaked at 700°C and air-cooled, a low-alloy composition Fe-12Cr-5Ni-4Al (in wt %) was selected for scale up and property evaluation.

Comparison of Recovery and Recrystallization in Stainless Steel Following Plane-Wave Shock Loading and Explosive Forming

1970 ◽  
Vol 28 ◽  
pp. 428-429 ◽  
Author(s):  
J. A. Korbonski ◽  
L. E. Murr
Keyword(s):  
Stainless Steel ◽  
Shock Loading ◽  
Pressure Pulse ◽  
Shock Pressure ◽  
304 Stainless Steel ◽  
Strain Rates ◽  
Two Dimensional ◽  
Aisi 304 Stainless Steel ◽  
Aisi 304 ◽  
Explosive Forming

Comparison of recovery rates in materials deformed by a unidimensional and two dimensional strains at strain rates in excess of 104 sec.−1 was performed on AISI 304 Stainless Steel. A number of unidirectionally strained foil samples were deformed by shock waves at graduated pressure levels as described by Murr and Grace. The two dimensionally strained foil samples were obtained from radially expanded cylinders by a constant shock pressure pulse and graduated strain as described by Foitz, et al.

Some aspects of the defect structure in an austenitic stainless steel

1978 ◽  
Vol 36 (1) ◽  
pp. 314-315
Author(s):  
R. Gonzalez ◽  
L. Bru
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Cellular Structures ◽  
Total Strain Amplitude ◽  
Total Deformation ◽  
Density Of Dislocations ◽  
Planar Arrays ◽  
Stacking Fault Tetrahedra ◽  
Distribution Of Dislocations ◽  
Very High

The analysis of stacking fault tetrahedra (SFT) in fatigued metals (1,2) is somewhat complicated, due partly to their relatively low density, but principally to the presence of a very high density of dislocations which hides them. In order to overcome this second difficulty, we have used in this work an austenitic stainless steel that deforms in a planar mode and, as expected, examination of the substructure revealed planar arrays of dislocation dipoles rather than the cellular structures which appear both in single and polycrystals of cyclically deformed copper and silver. This more uniform distribution of dislocations allows a better identification of the SFT.The samples were fatigue deformed at the constant total strain amplitude Δε = 0.025 for 5 cycles at three temperatures: 85, 293 and 773 K. One of the samples was tensile strained with a total deformation of 3.5%.

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