Physiologic Determinants of Endothelin Concentrations in Human Saliva

Abstract Background: Salivary endothelin (ET) concentrations have been shown to correlate with disease severity in patients with chronic heart failure (CHF). We undertook the present study to evaluate the stability of salivary ET under different handling conditions to assess its suitability as a biochemical marker in screening, diagnosis, and management of CHF. Methods: Saliva samples were collected from healthy individuals and/or CHF patients, subjected to different handling conditions, and then stored at −80 °C until assayed by an ELISA for ET. Results: Salivary ET concentrations showed a time-dependent increase during storage at room temperature. After 72 h of incubation at room temperature, ET increased ∼2.8-fold (P = 0.03). Simultaneously, salivary big ET showed a time-dependent 11.2-fold decrease (P <0.0001). This activity was blocked by an ET-converting enzyme (ECE) inhibitor, suggesting that these changes were attributable to ECE-dependent cleavage of endogenous big ET in saliva. Ex vivo conversion was also observed when samples were stored at 4 °C, but the magnitude of these changes was markedly smaller (P <0.0001). Posture also affected salivary ET concentrations in CHF patients. With a change from supine to seated rest, salivary ET concentrations increased 1.5- and 1.8-fold after 20 and 40 min, respectively (P = 0.01). With a return to supine rest, salivary ET concentrations returned to baseline concentrations (P = 0.008). Conclusions: These data suggest that saliva sampling and handling conditions could markedly affect measurement of salivary ET. In particular, care should be taken to minimize ECE-dependent enzymatic conversion of endogenous big ET in saliva.

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Effects of storage temperature and time before centrifugation on ionized calcium in blood collected in plain vacutainer tubes and silicone-separator (SST) tubes.

Clinical Chemistry ◽

10.1093/clinchem/30.4.553 ◽

1984 ◽

Vol 30 (4) ◽

pp. 553-556 ◽

Cited By ~ 28

Author(s):

J Toffaletti ◽

N Blosser ◽

K Kirvan

Keyword(s):

Room Temperature ◽

Storage Temperature ◽

Ionized Calcium ◽

Blood Collection ◽

Healthy Individuals ◽

Blood Samples ◽

The Mean ◽

Whole Blood Samples ◽

The Stability ◽

Blood Collection Tubes

Abstract We studied the stability of ionized calcium and pH in samples stored at either room temperature or 4 degrees C, in centrifuged and uncentrifuged blood-collection tubes and in centrifuged tubes containing a silicone-separator gel (SST tubes). At room temperature, in uncentrifuged blood from healthy individuals, mean ionized calcium usually increased no more than 10 mumol/L per hour; at 4 degrees C it did not change detectably for 70 h. This stability was fortuitous, however: the concentrations of both hydrogen and lactate ions in these samples increased, apparently with offsetting effects on the concentration of ionized calcium. Blood stored for 70 h at 4 degrees C in centrifuged SST tubes, although showing a slightly greater change in ionized calcium, had less change of pH and no change in the ionized calcium corrected to pH 7.4. In 11 heparinized whole-blood samples from eight patients in intensive care, the mean change per hour in ionized calcium and pH after storage at room temperature was +10 mumol/L and -0.04 units, respectively.

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Stability of Routine Hematology Sample Using The Medonic M-Series Analyzer

Medical Laboratory Technology Journal ◽

10.31964/mltj.v0i0.305 ◽

2020 ◽

Vol 6 (2) ◽

pp. 108

Author(s):

Eva Ayu Maharani ◽

Dewi Astuti

Keyword(s):

Room Temperature ◽

Storage Conditions ◽

Healthy Individuals ◽

Fresh Sample ◽

Blood Samples ◽

Significant Difference ◽

Hematology Analyzer ◽

Whole Blood Samples ◽

The Stability ◽

Wbc Count

Routine hematology tests (Hb, Hct, RBC, WBC, PLT) generally done by automation methods using a hematology analyzer. Ideally, the examinations should be done as soon as possible, although, in some circumstances, it can be delayed. Based on the literature, the sample for routine hematology testing should be processed within 4 – 8 hours of venesection. Some studies revealed that the sample could be stored for up to 48 hours, and it can be influenced by the technology applied to the hematology analyzer. Studies conducted to see the stability of the samples using a hematology analyzer with impedance technology. Tests performed on whole blood samples collected from 12 ostensibly healthy individuals, immediately after collection (fresh sample, <1hour) and 2h, 4h, 6h, 8h, 24h, 48h afterward. The samples stored at room temperature (20-240C) and 2-60C. There are no significant differences after 48 h under different storage conditions for Hb, Hct, RBC, PLT count, except for WBC count that has a significant difference at temperature 2-60C. CV for Hb, Hct, RBC, PLT, WBC count is less than 5% at room temperature. WBC and PLT count have a CV of more than 5% at 2-60 C. Sample for Hb, Hct, RBC was found to be stable up to 48 h at room temperature and 2-60C. PLT and WBC count were stable for 48 h if stored at room temperature.

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Stability of Routine Hematology Sample Using The Medonic M-Series Analyzer

Medical Laboratory Technology Journal ◽

10.31964/mltj.v6i2.305 ◽

2020 ◽

Vol 6 (2) ◽

pp. 108

Author(s):

Eva Ayu Maharani ◽

Dewi Astuti

Keyword(s):

Room Temperature ◽

Storage Conditions ◽

Healthy Individuals ◽

Fresh Sample ◽

Blood Samples ◽

Significant Difference ◽

Hematology Analyzer ◽

Whole Blood Samples ◽

The Stability ◽

Wbc Count

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Assay for the Measurement of Copeptin, a Stable Peptide Derived from the Precursor of Vasopressin

Clinical Chemistry ◽

10.1373/clinchem.2005.060038 ◽

2006 ◽

Vol 52 (1) ◽

pp. 112-119 ◽

Cited By ~ 613

Author(s):

Nils G Morgenthaler ◽

Joachim Struck ◽

Christine Alonso ◽

Andreas Bergmann

Keyword(s):

Critically Ill ◽

Critically Ill Patients ◽

Room Temperature ◽

Ex Vivo ◽

Polyclonal Antibodies ◽

Plasma Samples ◽

Healthy Individuals ◽

Terminal Part ◽

Reliable Measurement ◽

Water Load

Abstract Background: Arginine vasopressin (AVP) is a key regulator of water balance, but its instability makes reliable measurement difficult and precludes routine use. We present a method for quantifying AVP release by use of copeptin, a glycopeptide comprising the C-terminal part of the AVP prohormone. Methods: We measured copeptin in 50-μL serum and plasma samples from healthy individuals and from critically ill patients with sepsis. Our sandwich immunoluminometric assay used 2 polyclonal antibodies to amino acids 132–164 of pre-provasopressin. Results: The assay yielded results within 3 h. The analytical detection limit was 1.7 pmol/L, and the interlaboratory CV was <20% for values >2.25 pmol/L. The assay was linear on dilution of the analyte. Ex vivo copeptin stability (<20% loss of analyte) for at least 7 days at room temperature and 14 days at 4 °C was shown for serum and EDTA-, heparin-, and citrate plasma. Copeptin (median, 4.2 pmol/L; range, 1–13.8 pmol/L) was detectable in 97.5% of 359 healthy individuals and was not associated with age. Median concentrations were considerably higher in men than women, increased significantly after exercise, and were influenced by fasting and water load. Copeptin was significantly (P <0.001) increased in 60 critically ill patients with sepsis (median, 79.5 pmol/L; range, 10.6–228.0 pmol/L). The correlation between copeptin and AVP for 110 samples was r = 0.78 (P <0.0001). Conclusions: Copeptin is stable for days after blood withdrawal and can be quickly and easily measured. The copeptin assay may be a useful alternative to direct measurement of AVP concentration.

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Stability of parathyroid hormone ex vivo in haemodialysis patients

Annals of Clinical Biochemistry International Journal of Laboratory Medicine ◽

10.1258/000456303763046175 ◽

2003 ◽

Vol 40 (2) ◽

pp. 191-193 ◽

Cited By ~ 13

Author(s):

T. K. Teal ◽

M. Reed ◽

P. E. Stevens ◽

E. J. Lamb

Keyword(s):

Parathyroid Hormone ◽

Room Temperature ◽

Ex Vivo ◽

Renal Dialysis ◽

Blood Collection ◽

Dialysis Patients ◽

Edta Plasma ◽

The Stability ◽

End Stage ◽

Blood Collection Tubes

Background: The stability of parathyroid hormone (PTH) in blood ex vivo is a significant practical problem for laboratories and clinicians. Several studies have suggested that PTH is more stable in blood collected into a potassium edetate (EDTA) preservative. Methods: To confirm that this was applicable to renal dialysis patients using our assay (Nichols chemiluminescence), we examined PTH stability in 13 patients with end-stage renal failure using three different blood collection tubes. Results: PTH remained stable in EDTA plasma for up to 48 h at room temperature. PTH was significantly reduced in serum collected into plain tubes after 2 h, and after 4 h in serum collected into serum separator tubes, at room temperature. Conclusion: In the assessment of renal osteodystrophy, the use of EDTA plasma can confer significant benefit, especially in busy laboratories where rapid frozen separation of blood may be hard to achieve.

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Plasminogen Depletion during Streptokinase Treatment or Two-Chain Urokinase Incubation Correlates with Decreased Clot Lysability Ex Vivo and In Vitro

Thrombosis and Haemostasis ◽

10.1055/s-0038-1649714 ◽

1993 ◽

Vol 70 (06) ◽

pp. 0998-1004 ◽

Cited By ~ 13

Author(s):

Páll T Önundarson ◽

H Magnús Haraldsson ◽

Lena Bergmann ◽

Charles W Francis ◽

Victor J Marder

Keyword(s):

Myocardial Infarction ◽

Ex Vivo ◽

Time Dependent ◽

State Variables ◽

Thrombolytic Treatment ◽

Direct Proportion ◽

Plasmin Activity ◽

Plasma Exposure ◽

The Relationship

SummaryThe relationship between lytic state variables and ex vivo clot lysability was investigated in blood drawn from patients during streptokinase administration for acute myocardial infarction. A lytic state was already evident after 5 min of treatment and after 20 min the plasminogen concentration had decreased to 24%, antiplasmin to 7% and fibrinogen 0.2 g/1. Lysis of radiolabeled retracted clots in the patient plasmas decreased from 37 ± 8% after 5 min to 21 ± 8% at 10 min and was significantly lower (8 ± 9%, p <0.005) in samples drawn at 20, 40 and 80 min. Clot lysability correlated positively with the plasminogen concentration (r = 0.78, p = 0.003), but not with plasmin activity. Suspension of radiolabeled clots in normal plasma pre-exposed to 250 U/ml two-chain urokinase for varying time to induce an in vitro lytic state was also associated with decreasing clot lysability in direct proportion with the duration of prior plasma exposure to urokinase. The decreased lysability correlated with the time-dependent reduction in plasminogen concentration (r = 0.88, p <0.0005). Thus, clot lysability decreases in conjunction with the development of the lytic state and the associated plasminogen depletion. The lytic state may therefore limit reperfusion during thrombolytic treatment.

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Methods for the Concentration of Bovine Ac-Globulin (Factor V)

Thrombosis and Haemostasis ◽

10.1055/s-0038-1654575 ◽

1961 ◽

Vol 06 (03) ◽

pp. 435-444 ◽

Cited By ~ 1

Author(s):

Ricardo H. Landaburu ◽

Walter H. Seegers

Keyword(s):

Room Temperature ◽

Barium Carbonate ◽

Deae Cellulose ◽

Reducing Agents ◽

Factor V ◽

Isoelectric Precipitation ◽

Stabilizing Agent ◽

Bovine Plasma ◽

The Stability

SummaryAn attempt was made to obtain Ac-globulin from bovine plasma. The concentrates contain mostly protein, and phosphorus is also present. The stability characteristics vary from one preparation to another, but in general there was no loss before 1 month in a deep freeze or before 1 week in an icebox, or before 5 hours at room temperature. Reducing agents destroy the activity rapidly. S-acetylmercaptosuccinic anhydride is an effective stabilizing agent. Greatest stability was at pH 6.0.In the purification bovine plasma is adsorbed with barium carbonate and diluted 6-fold with water. Protein is removed at pH 6.0 and the Ac-globulin is precipitated at pH 5.0. Rivanol and alcohol fractionation is followed by chromatography on Amberlite IRC-50 or DEAE-cellulose. The final product is obtained by isoelectric precipitation.

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Symmetrizable Difference Dchemes

Computational Methods in Applied Mathematics ◽

10.2478/cmam-2005-0001 ◽

2005 ◽

Vol 5 (1) ◽

pp. 3-50 ◽

Cited By ~ 2

Author(s):

Alexei A. Gulin

Keyword(s):

Initial Data ◽

Difference Scheme ◽

Difference Schemes ◽

Time Dependent ◽

Stability Boundaries ◽

Typical Representative ◽

Variable Weight ◽

The Stability ◽

Conditions Of Stability ◽

The Right

AbstractA review of the stability theory of symmetrizable time-dependent difference schemes is represented. The notion of the operator-difference scheme is introduced and general ideas about stability in the sense of the initial data and in the sense of the right hand side are formulated. Further, the so-called symmetrizable difference schemes are considered in detail for which we manage to formulate the unimprovable necessary and su±cient conditions of stability in the sense of the initial data. The schemes with variable weight multipliers are a typical representative of symmetrizable difference schemes. For such schemes a numerical algorithm is proposed and realized for constructing stability boundaries.

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XMODULATION IN MICEAND MEN: IL-10 PRODUCING CELLS INBLOOD AND LYMPHOID TISSUE

Clinical & Investigative Medicine ◽

10.25011/cim.v31i4.4789 ◽

2008 ◽

Vol 31 (4) ◽

pp. 3

Author(s):

L Barrett ◽

M Grant ◽

R Liwski ◽

K West

Keyword(s):

Immune System ◽

Peripheral Blood ◽

Lymphoid Tissue ◽

Mononuclear Cells ◽

Ex Vivo ◽

White Blood Cells ◽

Interleukin 10 ◽

Healthy Individuals ◽

Human Immune System ◽

Healthy Humans

Background: The human immune system provides remarkable protection from a plethora of pathogens, but can cause damage when activated for a prolonged time (as inpersistent infections) or against self (autoimmunity). Therefore, mechanisms of immune system downregulation and control are imperative. There is little data on how the immune system is controlled in healthy individuals. We recently described a novel population of white blood cells that constitutively produce the immunomodulatory cytokine interleukin-10 (IL-10). Our objective was to further delineate the distribution of these cells in human and mouse models, as well as potential triggers for interleukin-10 production in vitro. Methods: Human and animal protocols were reviewed and approved by the institutional ethics board and animal care facilities, and informed consent was obtained from all human donors. The ex vivo percentage of peripheral blood CD36^+IL-10^+ mononuclear cells was assessed by intracellular flow cytometry in 10 healthy individuals. IL-10 production after exposure to twoCD36 ligands, thrombospondin and oxidized low density lipoprotein (oxLDL) was measured at 8 hours. Peripheral blood mononuclear cells and splenocytes from BL/6 (n=5) and Balb/c (n=1) micewere assessed for CD36^+IL-10^+ cells ex vivo as well. Results: The percentage of CD36^+IL-10^+ cells in peripheral blood fromhealthy individuals ranges between 0.1% and 0.9%. The percentage was similar in mouse peripheral blood, with a range of 0.4%-1.1%. These cells were also found in mouse spleen at a higher frequency than peripherally (1.1-1.5%). Human CD36^+IL-10^+ cells have more IL-10 when exposed to thrombospondin, oxLDL. Conclusions: Our novel population of IL-10 producing cells is found not only in healthy humans, but also in lymphoid tissue and blood from pathogen free mice. This highlights the evolutionary conservation of the cell across species, and suggests an important homeostatic function. The physiologic ligands for CD36 are ubiquitous in circulation, and ourin vitro data suggests a link between CD36 ligation and IL-10 production. IL-10 is a known immune system modulator, and its production by these cells may help maintain homeostaticcontrol of the immune system.

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Tyrosine-Selective Bioconjugation with Iminoxyl Radicals

10.26434/chemrxiv.12278717 ◽

2020 ◽

Author(s):

Katsuya Maruyama ◽

Takashi Ishiyama ◽

Yohei Seki ◽

Kounosuke Oisaki ◽

Motomu Kanai

Keyword(s):

Reaction Time ◽

Steric Hindrance ◽

Room Temperature ◽

Water Soluble ◽

Light Irradiation ◽

Sodium Ascorbate ◽

Iminoxyl Radical ◽

Short Reaction Time ◽

Modified Peptides ◽

The Stability

A novel Tyr-selective protein bioconjugation using the water-soluble persistent iminoxyl radical is described. The conjugation proceeded with high Tyr-selectivity and short reaction time under biocompatible conditions (room temperature in buffered media under air). The stability of the conjugates was tunable depending on the steric hindrance of iminoxyl. The presence of sodium ascorbate and/or light irradiation promoted traceless deconjugation, restoring the native Tyr structure. The method is applied to the synthesis of a protein-dye conjugate and further derivatization to azobenzene-modified peptides.

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