scholarly journals Carbon isotope ratios of endogenous steroids found in human serum—method development, validation, and reference population-derived thresholds

2021 ◽  
Author(s):  
Thomas Piper ◽  
Hans Geyer ◽  
Eberhard Nieschlag ◽  
Lia Bally ◽  
Mario Thevis
Keyword(s):  
Method Development ◽  
Isotope Ratio Mass Spectrometry ◽  
Dehydroepiandrosterone Sulfate ◽  
Reference Population ◽  
Population Based ◽  
Sample Volume ◽  
Assay Sensitivity ◽  
Plasma Steroids ◽  
Endogenous Reference ◽  
Concentration Ratios

AbstractIn order to detect the misuse of testosterone (T), urinary steroid concentrations and concentration ratios are quantified and monitored in a longitudinal manner to enable the identification of samples exhibiting atypical test results. These suspicious samples are then forwarded to isotope ratio mass spectrometry (IRMS)–based methods for confirmation. Especially concentration ratios like T over epitestosterone (E) or 5α-androstanediol over E proved to be valuable markers. Unfortunately, depending on the UGT2B17 genotype and/or the gender of the athlete, these markers may fail to provide evidence for T administrations when focusing exclusively on urine samples. In recent years, the potential of plasma steroids has been investigated and were found to be suitable to detect T administrations especially in female volunteers. A current drawback of this approach is the missing possibility to confirm that elevated steroid concentrations are solely derived from an administration of T and cannot be attributed to confounding factors. Therefore, an IRMS method for plasma steroids was developed and validated taking into account the comparably limited sample volume. As endogenous reference compounds, unconjugated cholesterol and dehydroepiandrosterone sulfate were found suitable, while androsterone and epiandrosterone (both sulfo-conjugated) were chosen as target analytes. The developed method is based on multi-dimensional gas chromatography coupled to IRMS in order to optimize the overall assay sensitivity. The approach was validated, and a reference population encompassing n = 65 males and females was investigated to calculate population-based thresholds. As proof-of-concept, samples from volunteers receiving T replacement therapies and excretion study samples were investigated. Graphical abstract

scholarly journals Low Levels of Estradiol Are Associated with Vertebral Fractures in Older Men, But Not Women: The Rancho Bernardo Study1

2000 ◽  
Vol 85 (1) ◽  
pp. 219-223 ◽  
Author(s):  
Elizabeth Barrett-Connor ◽  
Judith E. Mueller ◽  
Denise G. von Mühlen ◽  
Gail A. Laughlin ◽  
Diane L. Schneider ◽  
...  
Keyword(s):  
Vertebral Fractures ◽  
Critical Role ◽  
Dehydroepiandrosterone Sulfate ◽  
Older Men ◽  
Community Dwelling ◽  
Total Testosterone ◽  
Skeletal Health ◽  
Lateral Spine ◽  
Assay Sensitivity ◽  
Endogenous Estrogen

This longitudinal study included 288 postmenopausal women without estrogen use (median age, 72 yr) and 352 men (median age, 66 yr). All were community-dwelling, ambulatory, and Caucasian. Blood for hormone assays (total and bioavailable estradiol and testosterone, estrone, androstenedione, dihydrotestosterone, dehydroepiandrosterone, and dehydroepiandrosterone sulfate) was obtained in 1984–1987, and vertebral fractures were diagnosed from lateral spine radiographs obtained in 1992–1996. At least one vertebral fracture was found in 21% of women and 8% of men. Among men, age-adjusted hormone levels differed by fracture status only for total (64.1 vs. 75.4 pmol/L, P = 0.012) and bioavailable (43.0 vs. 51.4 pmol/L, P = 0.008) estradiol. There was a graded association between higher concentrations of total and bioavailable estradiol and lower fracture prevalence (trend P < 0.01 for both hormones). Men with total testosterone levels compatible with hypogonadism (<7 nmol/L) were not more likely to have vertebral fractures. In women, none of the measured sex hormones was associated with vertebral fractures. There was also no increased prevalence of fractures in women with estradiol levels below the assay sensitivity (<11 pmol/L). These data suggest that estrogen plays a critical role in the skeletal health of older men and confirm other studies showing no association of postmenopausal endogenous estrogen levels with vertebral fractures in older women.

scholarly journals Multicenter Comparison of PCR Assays for Detection of Human Herpesvirus 8 DNA in Semen

1999 ◽  
Vol 37 (5) ◽  
pp. 1298-1301 ◽  
Author(s):  
Philip E. Pellett ◽  
Thomas J. Spira ◽  
Omar Bagasra ◽  
Chris Boshoff ◽  
Lawrence Corey ◽  
...  
Keyword(s):  
Artificial Insemination ◽  
Human Herpesvirus ◽  
Population Based ◽  
Human Herpesvirus 8 ◽  
Hiv Positive ◽  
Assay Sensitivity ◽  
Herpesvirus 8 ◽  
Immunodeficiency Virus ◽  
Pcr Assays ◽  
Positive Results

Reported prevalences of human herpesvirus 8 (HHV-8) (Kaposi’s sarcoma-associated herpesvirus) in semen have ranged widely. This is possibly due to differences in assay sensitivity, geographic or population-based differences in the true presence of the virus in semen, and PCR contamination. This study assessed interlaboratory sensitivity and reproducibility in the analysis of blinded experimental panels, each consisting of 48 specimens and being composed of semen specimens from different healthy artificial-insemination donors (n = 30) and human immunodeficiency virus (HIV)-infected patients (n = 7) plus positive (n = 4) and negative (n = 7) controls. The experimental panels analyzed in each laboratory were identical except for being independently coded. Of 10 experiments done in five laboratories, 5 experiments from three laboratories had evidence of PCR contamination; all instances of contamination were in the context of nested PCR procedures. In the experiments with no false-positive results, HHV-8 DNA was detected in three (8%) of the 37 semen specimens (two from artificial-insemination donors and one from an HIV-positive patient) but in only 3 (1.6%) of the 184 PCRs in which these specimens were analyzed. This suggests that HHV-8 DNA is present in semen at concentrations that can be too low to allow its consistent detection. This study emphasizes the importance of performing blinded, multi-institution experiments to provide a coherent basis for comparing results and to motivate standardization of methods.

Importance of probe design for bioanalysis of oligonucleotides using hybridization-based LC-fluorescence assays

Bioanalysis ◽  
2019 ◽  
Vol 11 (21) ◽  
pp. 1917-1925 ◽  
Author(s):  
Yuhuan Ji ◽  
Yijiang Liu ◽  
Wanhong Xia ◽  
Alexander Behling ◽  
Min Meng ◽  
...  
Keyword(s):  
Quantitative Determination ◽  
Human Plasma ◽  
Peptide Nucleic Acid ◽  
Dynamic Range ◽  
Sample Volume ◽  
Probe Design ◽  
Assay Sensitivity ◽  
Accuracy And Precision ◽  
Fluorescence Assays

Aim: The importance of the length and/or structure of fluorescently labeled PNA (peptide nucleic acid) probes for quantitative determination of oligodeoxynucleotides (ODNs) is demonstrated in human plasma using hybridization-based LC-fluorescence assays. The length of the PNA probes impacts the peak shape and chromatographic separation of the resulting PNA/ODN hybridization complexes and affects assay sensitivity, dynamic range and carryover. Methods: For quantitative determination of an 18-mer phosphodiester ODN (DNL1818) in human plasma, an assay utilizing an Atto dye-labeled 12-mer PNA probe provided a linear quantitation range of 0.1–50 ng/ml with excellent accuracy and precision (within -5.3–7.73%). Conclusion: This method provides a convenient method for sensitive and specific quantification of ODNs in biological matrix with limited sample volume and no special extraction.

scholarly journals LC-MS/MS METHOD DEVELOPMENT AND VALIDATION FOR THE DETERMINATION OF CARDIAZOL IN HUMAN PLASMA

2019 ◽  
pp. 380-385
Author(s):  
IRYNA DRAPAK ◽  
BORYS ZIMENKOVSKY ◽  
LINA PEREKHODA ◽  
SERGIY KOVALENKO ◽  
Liliya Logoyda
Keyword(s):  
Formic Acid ◽  
Human Plasma ◽  
Method Development ◽  
Accurate Method ◽  
Sample Volume ◽  
Ich Guidelines ◽  
Coefficients Of Variation ◽  
Method Development And Validation ◽  
Development And Validation

Objective: The main purpose of this study was to develop a simple, precise, rapid and accurate method for the quantification of cardiazol in human plasma. Methods: Chromatography was achieved on Discovery C18, 50 × 2.1 mm, 5 μm column. Samples were chromatographed in a gradient mode (eluent A (acetonitrile-water–formic acid, 5: 95: 0.1 v/v), eluent B (acetonitrile–formic acid, 100: 0.1 v/v)). The initial content of the eluent B of 8%, which increases linearly to 1.0 min to 100%, is maintained up to 1.5 min and returned to the original 8% to 1.51 min. The mobile phase was delivered at a flow rate of 0.400 ml/min into the mass spectrometer ESI chamber. The sample volume was 300 μl. Results: The total chromatographic run time was 2.5 min and the elution of cardiazol and IS (difenoconazole) occurred at ~2.15 and 1.98 min, respectively. A linear response function was established at 1-100 ng/ml for cardiazol and difenoconazole in human plasma. The % mean recovery for cardiazol in LQC, MQC and HQC was 102.8 %, 100.3 % and 95.9 %. The lowest concentration with the RSD<20% was taken as LLOQ and was found to be 1.10 ng/ml for cardiazol. The % accuracy of LLOQ samples prepared with the different biological matrix lots was found 109.7 %, which were found within the range of 80.00-120.00 % for the seven different plasma lots. % CV for LLOQ samples was observed as 11.9 %, which are within 20.00% of the acceptance criteria. The within-run coefficients of variation ranged between 0.311 % and 0.601 % for cardiazol. The within-run percentages of nominal concentrations ranged between 99.80 % and 100.41 % for cardiazol. The between-run coefficients of variation ranged between 0.332 % and 0.615 % for cardiazol. The between-run percentages of nominal concentrations ranged between 98.18 % and 101.21 % for cardiazol. Conclusion: A rapid method was developed for simultaneous determination of cardiazol in human plasma. The method was strictly validated according to the ICH guidelines. Acquired results demonstrate that the proposed strategy can be effortlessly and advantageously applied for routine examination of cardiazol in human plasma.

scholarly journals Resistance of Greenhouse, Laboratory, and Native Populations of Western Flower Thrips to Spinosad

HortScience ◽  
2005 ◽  
Vol 40 (1) ◽  
pp. 146-149 ◽  
Author(s):  
Rebecca L. Loughner ◽  
Daniel F. Warnock ◽  
Raymond A. Cloyd
Keyword(s):  
Frankliniella Occidentalis ◽  
Western Flower Thrips ◽  
Reference Population ◽  
Population Based ◽  
Alternative Methods ◽  
Ratio Analysis ◽  
Flower Thrips ◽  
Native Populations ◽  
History Of ◽  
Thrips Population

Western flower thrips (Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae)] collected from greenhouse, laboratory, and native populations were evaluated for resistance to the insecticide spinosad. Individual cut stems of transvaal daisy (Gerbera jamesonii H. Bolus ex Hook. f.) were inoculated with 25 adults from 1 of 9 thrips populations and maintained in isolation chambers. Treatments of no spray, water spray, spinosad at one-half label rate (0.41 mL·L-1) and spinosad at the recommended label rate (0.81 mL·L-1) were applied to the flowers. Three days after treatment, the number of live and dead thrips was recorded. Significantly more thrips were recovered from the control treatments than the spinosad treatments. Thrips survival varied by treatment and insect population. Based on an odds ratio analysis, the likelihood of recovering live thrips was greater in the IL-GH1 (Illinois greenhouse) population than in the NV-N1 (Nevada native) reference population for both spinosad treatments, suggesting resistance to spinosad in the IL-GH1 population. The IL-GH1 population was collected from a greenhouse regularly sprayed with spinosad whereas the NV-N1 population was collected in Incline Village, Nev., on wildflowers with no history of exposure to spinosad. This is the first documented indication of spinosad resistance in a thrips population. In comparison to the NV-N1 reference population, none of the populations collected from laboratory or native nonagricultural environments exhibited evidence of resistance to spinosad. Resistance to an insecticide with a novel mode of action, such as spinosad, indicates the necessity of rotating insecticides and implementing alternative methods of managing western flower thrips. Chemical names used: spinosad including spinosyn A and spinosyn D (Conserve SC).

scholarly journals Physical fitness of children and youth with asthma in comparison to the reference population

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Anke Hanssen-Doose ◽  
Robert Jaeschke ◽  
Claudia Niessner ◽  
Doris Oriwol ◽  
Annette Worth
Keyword(s):  
Physical Fitness ◽  
Muscular Strength ◽  
Reference Population ◽  
Population Based ◽  
German Population ◽  
State Of Health ◽  
General State ◽  
Cross Sectional ◽  
Test Items ◽  
Cardiorespiratory Endurance

Abstract Background Physical fitness is an essential marker of health. The literature regarding the question of whether individuals with asthma have reduced physical fitness compared to their non-asthmatic peers is inconsistent and focuses on the cardiorespiratory endurance dimension. This study provides a comparison of different dimensions of physical fitness in individuals with and without asthma on the basis of the German population-based study “KiGGS” (German Health Interview and Examination Survey for Children and Adolescents) and its in-depth study “MoMo” (2009–2012: wave 1 and 2014–2017: wave 2). Methods In total, 7731 individuals aged 6–30 years were included in this cross-sectional analysis at two measurement waves, including 353 individuals with and 7378 without asthma. The 12-month prevalence of physician-diagnosed asthma was assessed by interview. Physical fitness was measured by six test items of the MoMo test profile. “Cardiorespiratory endurance” was measured by an ergometric test, “muscular strength” by standing long jump, push-ups and sit-ups and “coordination” by jumping sideways and balancing backwards. Because of the broad age range of the sample, age- and sex-specific percentiles were used. Physical activity, age, gender and general state of health were assessed by questionnaire. Results The individuals with asthma reported a poorer general state of health at both measurement waves. However, the results of the fitness tests indicated that they were as physically fit as their peers without asthma in relation to cardiorespiratory endurance and muscular strength. The mean percentiles were all within the same range. The results of the comparisons of coordination performance were inconsistent. At wave 1 they were within the same range, at wave 2 individuals with asthma showed a poorer coordination performance (p = 0.041; HL = 4.125, CI of HL 0.155–8.125). Conclusions To the best of our knowledge, this is the first study to compare the physical fitness of individuals with and without asthma by considering several dimensions of physical fitness. The study demonstrates that cardiorespiratory endurance and muscular strength are not reduced in individuals with asthma. The results of the comparisons at the two measurement waves were remarkably stable.

scholarly journals A HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY–MASS SPECTROMETRY/MASS SPECTROMETRY METHOD DEVELOPMENT FOR THE QUANTITATIVE DETERMINATION OF BISOPROLOL FROM CACO-2 CELL MONOLAYERS

2018 ◽  
Vol 11 (4) ◽  
pp. 386
Author(s):  
Liliya Logoyda ◽  
Dmytro Korobko
Keyword(s):  
Mass Spectrometry ◽  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
High Performance ◽  
Method Development ◽  
Sample Volume ◽  
Liquid Chromatography Mass Spectrometry ◽  
Cell Monolayers ◽  
Chromatography Mass Spectrometry

 Objective: A simple, rapid high-performance liquid chromatography–mass spectrometry (MS)/MS method was developed for the determination of bisoprolol from confluent Caco-2 monolayers and from aqueous solution.Methods: Chromatography was achieved on discovery C 18, 50 mm×2.1 mm, 5 μm column. Samples were chromatographed in a gradient mode (eluent A [acetonitrile:water:formic acid, 5:95:0.1 v/v] and eluent B [acetonitrile:formic acid, 100:0.1 v/v]). The initial content of the eluent B is 0%, which increases linearly by 1.0 min to 100% and to 1.01 min returns to the initial 0%. The mobile phase was delivered at a flow rate of 0.400 ml/min into the mass spectrometer ESI chamber. The sample volume was 5 μl.Results: Under these conditions, bisoprolol was eluted at 1.49 min. According to the Caco-2 test results, bisoprolol appeared to have moderate to high permeability. It should be noted that the recovery value for bisoprolol is 97.69%. Caco-2 permeability values for bisoprolol are in agreement with BCS Class I classification for these drugs and their known high bioavailability in humans.Conclusion: From results of analysis, it can be concluded that developed method is simple and rapid for the determination of bisoprolol from confluent Caco-2 monolayers and from aqueous solution. Acquired results demonstrate that proposed strategy can be effortlessly and advantageously applied for the examination of bisoprolol from Caco-2 cell monolayers.

scholarly journals Sex-specific Estrogen Levels and Reference Intervals from Infancy to Late Adulthood Determined by LC-MS/MS

2019 ◽  
Vol 105 (3) ◽  
pp. 754-768 ◽  
Author(s):  
Hanne Frederiksen ◽  
Trine Holm Johannsen ◽  
Stine Ehlern Andersen ◽  
Jakob Albrethsen ◽  
Selma Kløve Landersoe ◽  
...  
Keyword(s):  
Method Development ◽  
Premenopausal Women ◽  
Population Based ◽  
Reference Intervals ◽  
Future Research ◽  
Specific Reference ◽  
Reference Ranges ◽  
Pubertal Stage ◽  
Cross Sectional ◽  
Liquid Chromatography Tandem Mass

Abstract Context The lack of sensitive and robust analytical methods has hindered the reliable quantification of estrogen metabolites in subjects with low concentrations. Objective To establish sex-specific reference ranges for estrone (E1) and estradiol (E2) throughout life and to evaluate sex-differences using the state-of-the-art liquid chromatography tandem mass spectrometry (LC-MS/MS) method for quantification of E1, E2, and estriol (E3). Design LC-MS/MS method development and construction of estrogen reference ranges. Settings Population-based cross-sectional cohorts from the greater Copenhagen and Aarhus areas. Participants Healthy participants aged 3 months to 61 years (n = 1838). Results An isotope diluted LC-MS/MS method was developed and validated for measurements of serum E1, E2, and E3. Limits of detections (LODs) were 3 pmol/L (E1), 4 pmol/L (E2), and 12 pmol/L (E3), respectively. This sensitive method made it possible to differentiate between male and female concentration levels of E1 and E2 in children. In girls, E2 levels ranged from &lt;LOD to 100 pmol/L during mini-puberty, whereas it was ≤20 pmol/L during childhood. E1 and E2 increased with age and pubertal breast stage and varied during the menstrual cycle; E1 was lower than E2 in girls and premenopausal women, and higher than E2 in postmenopausal women. In boys, E1 and E2 increased with age and pubertal stage, whereas little changes with age were observed in men. High E3 concentrations were confirmed in pregnant women. Conclusion Reference ranges of simultaneous quantification of E1 and E2 by this novel specific and highly sensitive LC-MS/MS method provide an invaluable tool in clinical practice and in future research studies.

scholarly journals Isotope ratio mass spectrometry in antidoping analysis: The use of endogenous reference compounds

2019 ◽  
Vol 33 (6) ◽  
pp. 579-586 ◽  
Author(s):  
Xavier de la Torre ◽  
Daniel Jardines ◽  
Davide Curcio ◽  
Cristiana Colamonici ◽  
Francesco Botrè
Keyword(s):  
Mass Spectrometry ◽  
Isotope Ratio ◽  
Isotope Ratio Mass Spectrometry ◽  
Endogenous Reference ◽  
Antidoping Analysis

scholarly journals Visual Complications in Patients with Biopsy-proven Giant Cell Arteritis: A Population-based Study

2016 ◽  
Vol 43 (8) ◽  
pp. 1559-1565 ◽  
Author(s):  
Muna Saleh ◽  
Carl Turesson ◽  
Martin Englund ◽  
Peter A. Merkel ◽  
Aladdin J. Mohammad
Keyword(s):  
Giant Cell Arteritis ◽  
Giant Cell ◽  
Inflammatory Responses ◽  
Temporal Artery ◽  
Reference Population ◽  
Population Based ◽  
Population Based Study ◽  
Protein Levels ◽  
Reactive Protein ◽  
Background Population

Objective.To study the clinical and laboratory characteristics of patients with biopsy-proven giant cell arteritis (GCA) with visual complications, and to evaluate the incidence rate of visual complications in GCA compared to the background population.Methods.Data from 840 patients with GCA in the county of Skåne, Sweden, diagnosed between 1997 and 2010, were used for this analysis. Cases with visual complications were identified from a diagnosis registry and confirmed by a review of medical records. The rate of visual complications in patients with GCA was compared with an age- and sex-matched reference population.Results.There were 85 patients (10%) who developed ≥ 1 visual complication after the onset of GCA. Of the patients, 18 (21%) developed unilateral or bilateral complete visual loss. The mean age at diagnosis was 78 years (± 7.3); 69% were women. Compared with patients without visual complications, those with visual complication had lower C-reactive protein levels at diagnosis and were less likely to have headache, fever, and palpable abnormal temporal artery. The use of β-adrenergic inhibitors was associated with visual complications. The incidence of visual complications among patients with GCA was 20.9/1000 person-years of followup compared to 6.9/1000 person-years in the reference population, resulting in a rate ratio of 3.0 (95% CI 2.3–3.8).Conclusion.Ten percent of patients with GCA developed visual complications, a rate substantially higher than that of the general population. Patients with GCA who had visual complications had lower inflammatory responses and were more likely to have been treated with β-adrenergic inhibitors compared with patients without visual complications.

Sign in / Sign up

Export Citation Format

Share Document