Prolonged stability of brain natriuretic peptide: importance for non-invasive assessment of cardiac function in clinical practice

1998 ◽  
Vol 95 (3) ◽  
pp. 235-239 ◽  
Author(s):  
Martin G. BUCKLEY ◽  
Neil J. MARCUS ◽  
Magdi H. YACOUB ◽  
R. J. Donald
Keyword(s):  
Clinical Practice ◽  
Cardiac Function ◽  
Room Temperature ◽  
Heart Function ◽  
Transplant Recipients ◽  
Non Invasive ◽  
Significant Fall ◽  
Hospital Outpatient Clinic ◽  
Initial Plasma ◽  
The Stability

1.BNP and ANP are important research indices of severity of heart failure. However, uncertainty regarding the stability of these peptides at room temperature has limited their use to assess cardiac function in routine clinical practice. 2.We assessed the stability of BNP and ANP in blood samples left for 2 ;h or 2 days at room temperature compared with levels in blood processed immediately (initial). These times were chosen to reflect possible times for samples to be processed in a hospital outpatient clinic (2 ;h) or a blood sample posted to a laboratory from general practice (2 days). Samples were obtained from eight heart transplant recipients. Blood was separated and plasma stored immediately after collection (initial) and after 2 ;h or 2 days at room temperature respectively. 3.Initial plasma BNP and ANP values measured by radioimmunoassay after Sep-Pak extraction were 38.9±11.1(S.E.M.) pg/ml and 113.6±28.1 ;pg/ml, respectively. After 2 ;h at room temperature there was no significant fall in either peptide level (35.5±9.9 ;pg/ml, BNP; 104.9±30.6 ;pg/ml, ANP). However, after 2 days at room temperature there was a significant fall in ANP to 38.1±12.6 ;pg/ml (P< 0.005 versus initial level). In contrast, there was no significant fall in BNP after 2 days (32.0±8.4 ;pg/ml). After 2 days at room temperature only 30.4±4.3% of the ANP remained, but 86.0±5.0% of BNP compared with the initial ANP and BNP measurements. 4.Our study clearly showed that ANP is stable for 2 ;h and thus could be useful as a screening test for heart disease in hospital. In contrast, BNP remained stable for 2 days. Measuring BNP may thus be practical as a test of heart function both for routine use in hospital and by general practitioners in the community.

Cardiac peptide stability, aprotinin and room temperature: importance for assessing cardiac function in clinical practice

1999 ◽  
Vol 97 (6) ◽  
pp. 689-695 ◽  
Author(s):  
Martin G. BUCKLEY ◽  
Neil J. MARCUS ◽  
Magdi H. YACOUB
Keyword(s):  
Clinical Practice ◽  
Cardiac Function ◽  
Natriuretic Peptide ◽  
Room Temperature ◽  
Heart Function ◽  
Routine Clinical Practice ◽  
Blood Samples ◽  
Initial Values ◽  
Significant Difference ◽  
The Stability

Brain natriuretic peptide (BNP), atrial natriuretic peptide (ANP) and N-terminal ANP are good research indices of the severity of heart failure. The stability of these peptides at room temperature has become an important factor in assessing their use as indicators of cardiac function in routine clinical practice. Inhibitors such as aprotinin are routinely added in the blood collection process, but may provide no benefit in sample collection and routine clinical practice. We assessed the stability of BNP, ANP and N-terminal ANP in blood samples collected in either the presence or the absence of the protease inhibitor aprotinin. Blood, either with or without aprotinin, was processed immediately (initial; 0 h) and after blood samples had been left for 3 h, 2 days or 3 days at room temperature. These times were chosen to reflect processing in a hospital outpatient clinic (2–3 h), or when posted from general practice (2–3 days). Initial plasma BNP, ANP and N-terminal ANP levels in the absence of aprotinin were 28.2±5.4, 44.2±7.9 and 1997±608 pg/ml respectively, and were not significantly different from initial values in the presence of aprotinin (29.0±5.9, 45.2±8.0 and 2009±579 pg/ml respectively). After 3 h at room temperature, there was a significant fall in ANP in the absence of aprotinin (36.7±7.9 pg/ml; P< 0.005), but not in the presence of aprotinin (41.2±7.6 pg/ml). Both BNP and N-terminal ANP were unchanged in either the absence (BNP, 27.6±5.5 pg/ml; N-terminal ANP, 2099±613 pg/ml) or the presence (BNP, 29.4±5.6 pg/ml; N-terminal ANP, 1988±600 pg/ml) of aprotinin. After 2 days at room temperature, ANP had fallen significantly in both the absence (16.9±3.4 pg/ml) and the presence (24.0±5.0 pg/ml) of aprotinin compared with initial values, and there was a significant difference in ANP levels in the absence and presence of aprotinin (P< 0.001). ANP levels had decreased further after 3 days at room temperature, to 11.9±3.4 pg/ml (no aprotinin) and 20.3±5.0 pg/ml (aprotinin added); these values were significantly different (P = 0.002). In contrast, there was no change in the levels of BNP or N-terminal ANP after 2 or 3 days at room temperature, in either the absence or the presence of aprotinin. These studies indicate that aprotinin adds little benefit to the stability of cardiac peptides at room temperature. Blood samples for BNP and N-terminal ANP measurement used as a test of heart function in hospital clinics and by general practitioners in the community could be taken into blood tubes containing only EDTA as anticoagulant and without the additional step of adding the routinely used inhibitor aprotinin.

Prolonged stability of brain natriuretic peptide: importance for non-invasive assessment of cardiac function in clinical practice

1998 ◽  
Vol 95 (3) ◽  
pp. 235 ◽  
Author(s):  
Martin G. BUCKLEY ◽  
Neil J. MARCUS ◽  
Magdi H. YACOUB ◽  
Donald R.J. SINGER
Keyword(s):  
Clinical Practice ◽  
Cardiac Function ◽  
Brain Natriuretic Peptide ◽  
Natriuretic Peptide ◽  
Non Invasive

Assessment of the stability of N-terminal pro-brain natriuretic peptide in vitro: implications for assessment of left ventricular dysfunction

1999 ◽  
Vol 97 (3) ◽  
pp. 255-258 ◽  
Author(s):  
P. F. DOWNIE ◽  
S. TALWAR ◽  
I. B. SQUIRE ◽  
J. E. DAVIES ◽  
D. B. BARNETT ◽  
...  
Keyword(s):  
Clinical Practice ◽  
Brain Natriuretic Peptide ◽  
Natriuretic Peptide ◽  
Left Ventricular Dysfunction ◽  
Room Temperature ◽  
Ventricular Dysfunction ◽  
Plasma Concentrations ◽  
Left Ventricular ◽  
Blood Samples ◽  
The Stability

Plasma concentrations of N-terminal pro-brain natriuretic peptide (NT-proBNP) are raised in patients with left ventricular dysfunction. Measurement of this peptide has a potential diagnostic role in the identification and assessment of patients with heart failure. The stability of this peptide over time periods and conditions pertaining to routine clinical practice has not been reported previously. Blood samples were obtained from 15 subjects. One aliquot was processed immediately, and the remaining portions of the blood samples were stored for 24 h or 48 h at room temperature or on ice prior to processing. Plasma concentrations of NT-proBNP were measured with a novel immunoluminometric assay developed within our laboratory. Mean plasma concentrations of NT-proBNP were not significantly different whether blood samples were centrifuged immediately and stored at -70 °C or kept at room temperature or on ice for 24 h or 48 h. The mean percentage differences from baseline (reference standard) were +5.2% (95% confidence interval +18.2 to -7.8%) and +0.8% (+15.2 to -13.7%) after storage for 24 h at room temperature or on ice respectively, and +8.9% (+24.2 to -6.5%) and +3.2% (+15.1 to -0.9%) for storage for 48 h at room temperature or on ice respectively. Pearson correlation coefficients for baseline NT-proBNP concentrations compared with levels at 48 h at room temperature or on ice were r = 0.89 and r = 0.83 respectively (both P < 0.0001). Thus NT-proBNP extracted from plasma samples treated with EDTA and aprotinin is stable under conditions relevant to clinical practice.

Stability of varenicline concentration in saliva over twenty-one days at three storage temperatures

2021 ◽  
Author(s):  
Maria Novalen ◽  
Meghan J Chenoweth ◽  
Bin Zhao ◽  
Larry W Hawk, Jr. ◽  
Rachel F Tyndale
Keyword(s):  
Quality Control ◽  
Smoking Cessation ◽  
Room Temperature ◽  
Freezing And Thawing ◽  
Storage Duration ◽  
Non Invasive ◽  
Specimen Collection ◽  
Repeated Freezing ◽  
The Stability ◽  
Storage Temperatures

Abstract Introduction Varenicline is the most efficacious drug for smoking cessation; saliva varenicline concentrations can be useful for the evaluation of adherence in smoking cessation trials. Saliva is a useful non-invasive matrix for mail-in specimen collection, if stable. We investigated the stability of varenicline in saliva at different storage temperatures simulating the time it takes to mail in a sample. Methods We evaluated the concentrations of varenicline, nicotine, cotinine, 3’-hydroxycotinine and 3’-hydroxycotinine/cotinine (3HC/COT) ratio in quality control saliva samples (and after repeated freezing and thawing), and in smokers’ saliva samples, stored for up to 21 days at room temperature (~25°C), 4°C and -80°C. Results In saliva quality control samples, concentrations of varenicline, nicotine, cotinine, 3’-hydroxycotinine and 3HC/COT remained unchanged and showed little within-sample variation (CV≤5.5%) for up to 21 days at the three storage temperatures; they were also not altered after three thaw-freeze cycles. In smokers’ saliva, a significant main effect of storage duration, but not temperature, was observed for varenicline, cotinine and 3’-hydroxycotinine, but not for nicotine or the 3HC/COT ratio. However, these changes were within analytical (i.e. equipment) variation resulting in little within-sample variation (CV≤5.8%) for all analytes in smokers saliva. Conclusions Varenicline, the other analytes and the 3HC/COT ratio remained stable in saliva during storage for 21 days at all temperatures tested and after repeated freezing and thawing with only minor changes in concentration over time. These findings support the potential use of mail-in approach for saliva samples in varenicline smoking cessation clinical trials. Implications Assessing saliva varenicline concentrations can be useful for the evaluation of adherence in smoking cessation trials. Saliva is a non-invasive matrix suitable for mail-in specimen collection. This is the first investigation of stability of varenicline in saliva. Varenicline, nicotine, cotinine, 3’-hydroxycotinine and 3HC/COT were stable in saliva for up to 21 days at room temperature (~25°C), 4°C and -80°C, supporting the use of a mail-in approach for saliva specimen in smoking cessation trials.

scholarly journals Value of Echocardiography in the Treatment of Patients With Acute Heart Failure

2021 ◽  
Vol 8 ◽  
Author(s):  
Masaki Izumo
Keyword(s):  
Heart Failure ◽  
Clinical Practice ◽  
Cardiac Function ◽  
Acute Heart Failure ◽  
Optimal Treatment ◽  
Clinical Value ◽  
Mortality And Morbidity ◽  
Non Invasive ◽  
Life Threatening ◽  
Life Threatening Event

Heart failure (HF) is a burden in pandemic medicine resulting in high mortality and morbidity. Because acute HF is a life-threatening event, its diagnosis and choice of optimal treatment are important to improve outcomes. Furthermore, understanding the cause and hemodynamics of acute HF is important in selecting the optimal treatment for these patients. Echocardiography is widely used in daily clinical practice because of its non-invasive nature and excellent portability to understand cardiac function and hemodynamics. Echocardiography is highly recommended by guidelines in the practice of HF, but evidence is limited. In this review, I would like to share clinical value of echocardiography in the treatment of patients with acute HF and discuss the usefulness of echocardiography.

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

1961 ◽  
Vol 06 (03) ◽  
pp. 435-444 ◽  
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.

Tyrosine-Selective Bioconjugation with Iminoxyl Radicals

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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