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1.
Am J Nurs ; 121(10): 67, 2021 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-34554993

RESUMO

Stories of discovery, wrong turns, and hope.


Assuntos
Nível de Alerta , Endocrinologia , Hormônios , Hormônios/análise , Hormônios/fisiologia , Humanos , Radioimunoensaio
2.
PLoS One ; 16(9): e0257422, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34529698

RESUMO

OBJECTIVE: To determine if maternal plasma CRH and preterm birth history were associated with recurrent preterm birth risk in a high-risk cohort. STUDY DESIGN: Secondary analysis of pregnant women with a prior preterm birth ≤35 weeks receiving 17-alpha hydroxyprogesterone caproate for the prevention of recurrent spontaneous preterm birth. All women with a 24-week blood sample were included. Maternal plasma CRH level at 24- and 32-weeks' gestation was measured using both enzyme-linked immunosorbent assay (ELISA) and extracted radioimmunoassay (RIA) technologies. The primary outcome was spontaneous preterm birth <37 weeks. The association of CRH, prior preterm birth history, and the two combined was assessed in relation to recurrent preterm birth risk. RESULTS: Recurrent preterm birth in this cohort of 169 women was 24.9%. Comparing women who subsequently delivered <37 versus ≥37 weeks, mean levels of CRH measured by RIA were significantly different at 24 weeks (111.1±87.5 vs. 66.1±45.4 pg/mL, P = .002) and 32 weeks (440.9±275.6 vs. 280.2±214.5 pg/mL, P = .003). The area under the receiver operating curve (AUC) at 24 and 32 weeks for (1) CRH level was 0.68 (95% CI 0.59-0.78) and 0.70 (95% CI 0.59-0.81), (2) prior preterm birth history was 0.75 (95% CI 0.67-0.83) and 0.78 (95% CI 0.69-0.87), and (3) combined was 0.81 (95% CI 0.73-0.88, P = .001) and 0.81 (95% CI 0.72-0.90, P = .01) respectively for delivery <37 weeks. CRH measured by ELISA failed to correlate with gestational age or other clinical parameters. CONCLUSION: In women with a prior preterm birth, CRH levels were higher and had an earlier rise in women who experienced recurrent preterm birth. Second trimester CRH may be useful in identifying a sub-group of women with preterm birth due to early activation of the placenta-fetal adrenal axis. Assay methodology is a variable that contributes to difficulties in reproducibility of CRH levels in the obstetric literature.


Assuntos
Hormônio Liberador da Corticotropina/sangue , Placenta/metabolismo , Nascimento Prematuro , Caproato de 17 alfa-Hidroxiprogesterona/administração & dosagem , Adulto , Área Sob a Curva , Estudos de Coortes , Ensaio de Imunoadsorção Enzimática , Feminino , Idade Gestacional , Humanos , Gravidez , Resultado da Gravidez , Cuidado Pré-Natal , Estudos Prospectivos , Curva ROC , Radioimunoensaio , Fatores de Risco , Regulação para Cima
3.
J Immunol Methods ; 496: 113102, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34298066

RESUMO

BACKGROUND: In this study, we assessed the performance characteristics of a laboratory-developed radioimmunoassay (RIA) to detect N-type voltage-gated calcium channel (N-VGCC) antibodies found in several autoimmune neurologic diseases. METHODS: Four hundred and forty-five (n = 445) sera were evaluated, including 156 sera (50 positive and 106 negative for N-VGCC antibodies) previously tested at Mayo Clinic Laboratories (MCL) and 289 controls (n = 187 disease and n = 102 healthy). Specimens were analyzed with the RIA using N-VGCC labeled with 125I-ω-conotoxin GVIA. The RIA was compared to the predicate MCL assay using a tiered positive predictive value (PPV) approach. Other performance characteristics evaluated included specificity, precision, interference, and stability. RESULTS: Qualitative inter-laboratory agreement based on tiered PPVs was 100% for results >1.00 nmol/L (71% PPV), 48% for results of 0.10-0.99 nmol/L (24% PPV) and 22% for results of 0.04-0.10 nmol/L (19% PPV). Negative results showed 90% agreement (n = 106). Specificity in controls positive for other neural autoantibodies and healthy controls were 87% and 100%, respectively. Acceptable results were observed for other performance characteristics. CONCLUSIONS: Inter-laboratory correlations demonstrate equivalence between assays with some discrepancies between low positive results. Collaborative efforts aimed at assessing the clinical spectrum associated with these antibodies and consensus for harmonizing test performance are required for optimal categorization of patients.


Assuntos
Autoanticorpos/sangue , Autoimunidade , Canais de Cálcio Tipo N/imunologia , Síndrome Miastênica de Lambert-Eaton/diagnóstico , Radioimunoensaio , Testes Sorológicos , Adulto , Idoso , Especificidade de Anticorpos , Biomarcadores/sangue , Estudos de Casos e Controles , Estudos Transversais , Feminino , Humanos , Síndrome Miastênica de Lambert-Eaton/sangue , Síndrome Miastênica de Lambert-Eaton/imunologia , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Reprodutibilidade dos Testes , Adulto Jovem
4.
PLoS One ; 16(7): e0253807, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34242264

RESUMO

Determining values of plasma renin activity (PRA) or plasma active renin concentration (ARC), plasma aldosterone concentration (PAC), and aldosterone-to-renin ratio (ARR) is essential to diagnose primary aldosteronism (PA), but it takes several days with conventional radioimmunoassays (RIAs). Chemiluminescent enzyme immunoassays for PAC and ARC using the Accuraseed® immunoanalyzer facilitated the determination, but relations between Accuraseed® immunoanalyzer-based and RIA-based values in samples of PA confirmatory tests and adrenal venous sampling remained to be elucidated. We addressed this issue in the present study. This is a prospective, cross-sectional study. ARC and PAC values were measured by the Accuraseed® immunoanalyzer in samples, in which PRA and PAC values had been measured by the PRA-FR® RIA and SPAC®-S Aldosterone kits, respectively. The relations between Accuraseed® immunoanalyzer-based and RIA-based values were investigated with regression analyses. The optimal cutoff of Accuraseed® immunoanalyzer-based ARR for PA screening was determined by the receiver operating characteristic analysis. After log-log transformations, linear relations with high coefficients of determination were observed between Accuraseed® immunoanalyzer-based and RIA-based data of renin and aldosterone. Following the PA guidelines of Japan Endocrine Society, Accuraseed® immunoanalyzer-based cutoffs were calculated from the regression equations: the basal PAC for PA screening >12 ng/dL, PAC for the saline infusion test >8.2 ng/dL, ARC for the furosemide-upright test <15 pg/mL, and ARR for the captopril challenge test >3.09 ng/dL per pg/mL. The optimal cutoff of Accuraseed® immunoanalyzer-based ARR for PA screening was >2.43 ng/dL over pg/mL not to overlook bilateral PA patients. The present study provided conversion formulas between Accuraseed® immunoanalyzer-based and RIA-based values of renin, aldosterone, and ARR, not only in basal samples but also in samples of PA confirmatory tests and adrenal venous sampling. Although validation studies are awaited, the present study will become priming water of harmonization of renin and aldosterone immunoassays.


Assuntos
Aldosterona/sangue , Hiperaldosteronismo/diagnóstico , Programas de Rastreamento/instrumentação , Renina/sangue , Adulto , Idoso , Estudos Transversais , Feminino , Humanos , Hiperaldosteronismo/sangue , Japão , Medições Luminescentes/instrumentação , Medições Luminescentes/normas , Medições Luminescentes/estatística & dados numéricos , Masculino , Programas de Rastreamento/métodos , Programas de Rastreamento/normas , Programas de Rastreamento/estatística & dados numéricos , Pessoa de Meia-Idade , Estudos Prospectivos , Curva ROC , Radioimunoensaio/instrumentação , Radioimunoensaio/normas , Radioimunoensaio/estatística & dados numéricos , Valores de Referência
5.
Front Immunol ; 12: 683623, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34220834

RESUMO

Background: B-cell non-Hodgkin's lymphoma (B-NHL) is one of the major complications of primary Sjögren's syndrome (SS). Chronic inflammation and macrophages in SS minor salivary glands have been previously suggested as significant predictors for lymphoma development among SS patients. Lipoprotein-associated phospholipase A2 (Lp-PLA2)-a product mainly of tissue macrophages-is found in the circulation associated with lipoproteins and has been previously involved in cardiovascular, autoimmune, and malignant diseases, including lymphoma. Objective: The purpose of the current study was to investigate the contributory role of Lp-PLA2 in B-NHL development in the setting of primary SS. Methods: Lp-PLA2 activity in serum samples collected from 50 primary SS patients with no lymphoma (SS-nL), 9 primary SS patients with lymphoma (SS-L), and 42 healthy controls (HC) was determined by detection of [3H]PAF degradation products by liquid scintillation counter. Moreover, additional sera from 50 SS-nL, 28 SS-L, and 32 HC were tested for Lp-PLA2 activity using a commercially available ELISA kit. Lp-PLA2 mRNA, and protein expression in minor salivary gland (MSG) tissue samples derived from SS-nL, SS-L patients, and sicca controls (SC) were analyzed by real-time PCR, Western blot, and immunohistochemistry. Results: Serum Lp-PLA2 activity was significantly increased in SS-L compared to both SS-nL and HC by two independent methods implemented [mean ± SD (nmol/min/ml): 62.0 ± 13.4 vs 47.6 ± 14.4 vs 50.7 ± 16.6, p-values: 0.003 and 0.04, respectively, and 19.4 ± 4.5 vs 15.2 ± 3.3 vs 14.5 ± 3.0, p-values: <0.0001, in both comparisons]. ROC analysis revealed that the serum Lp-PLA2 activity measured either by radioimmunoassay or ELISA has the potential to distinguish between SS-L and SS-nL patients (area under the curve [AUC]: 0.8022, CI [95%]: 0.64-0.96, p-value: 0.004 for radioimmunoassay, and AUC: 0.7696, CI [95%]: 0.66-0.88, p-value: <0.0001, for ELISA). Lp-PLA2 expression in MSG tissues was also increased in SS-L compared to SS-nL and SC at both mRNA and protein level. ROC analysis revealed that both MSG mRNA and protein Lp-PLA2 have the potential to distinguish between SS-nL and SS-L patients (area under the curve [AUC] values of 0.8490, CI [95%]: 0.71-0.99, p-value: 0.0019 and 0.9444, CI [95%]: 0.79-1.00, p- value: 0.0389 respectively). No significant difference in either serum Lp-PLA2 activity or MSG tissue expression was observed between SS-nL and HC. Conclusions: Lp-PLA2 serum activity and MSG tissue mRNA/protein expression could be a new biomarker and possibly a novel therapeutic target for B-cell lymphoproliferation in the setting of SS.


Assuntos
1-Alquil-2-acetilglicerofosfocolina Esterase/metabolismo , Linfoma/etiologia , Linfoma/patologia , Síndrome de Sjogren/metabolismo , 1-Alquil-2-acetilglicerofosfocolina Esterase/genética , Adolescente , Adulto , Estudos de Casos e Controles , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Linfoma/sangue , Masculino , Pessoa de Meia-Idade , RNA Mensageiro/análise , Radioimunoensaio , Reação em Cadeia da Polimerase em Tempo Real , Síndrome de Sjogren/etiologia , Adulto Jovem
6.
Prague Med Rep ; 122(2): 80-95, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34137684

RESUMO

Determination of renin plasma levels is useful in the diagnosis of hypertension and in the therapeutic follow-up of hypertensive patients. Plasmatic concentration of renin decreases in patients with hypertension due to a primary hyperaldosteronism, contrary to renovascular hypertension where concentrations of renin and aldosterone are both elevated. Blood samples (serum, EDTA plasma) were analysed using two different chemiluminiscent methods CLIA LIAISON® and radioimmunoassay for aldosterone (IMMUNOTECH Beckman Coulter) and renin (Cisbio Bioassay) measurements were compared. We used both methods to ascertain the correlation between serum vs. EDTA plasma levels of aldosterone (RIA, CLIA) and renin (IRMA, CLIA) and to compare aldosterone to renin ratios for CLIA and for radioimmunoassay: serum aldosterone to plasma renin and plasma aldosterone to plasma renin. We compared serum aldosterone CLIA vs. RIA (rP=0.933, P<0.001) and plasma renin determined using CLIA vs. IRMA (rP=0.965, P=0.062). Furthermore, we used both methods to establish the correlation between the serum vs. plasma levels of aldosterone: RIA (rP=0.980, P<0.001); CLIA (rP=0.994, P=0.353) and serum vs. plasma levels of renin: IRMA (rP=0.948, P<0.001); CLIA (rP=0.921, P=0.011). Aldosterone (serum, plasma) to plasmatic renin ratios for CLIA (rP=0.999, P=0.286) and for radioimmunoassay (rP=0.992, P=0.025). Our data demonstrate that renin and aldosterone concentrations obtained using CLIA correlate with renin and aldosterone concentrations using radioimmunoassay methods. Correlation coefficients of pair results ranged from 0.921 to 0.994. Aldosterone (serum, EDTA plasma) to plasmatic renin ratios are comparable and any of them can be used with no significant differences found.


Assuntos
Aldosterona , Hiperaldosteronismo , Humanos , Luminescência , Radioimunoensaio , Renina
7.
Anal Bioanal Chem ; 413(17): 4531-4543, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34050775

RESUMO

We adapted a radioligand receptor binding assay for measuring insulin levels in unknown samples. The assay enables rapid and accurate determination of insulin concentrations in experimental samples, such as from insulin-secreting cells. The principle of the method is based on the binding competition of insulin in a measured sample with a radiolabeled insulin for insulin receptor (IR) in IM-9 cells. Both key components, radiolabeled insulin and IM-9 cells, are commercially available. The IR binding assay was used to determine unknown amounts of insulin secreted by MIN6 ß cell line after stimulation with glucose, arginine, ornithine, dopamine, and serotonin. The experimental data obtained by the IR binding assay were compared to the results determined by RIA kits and both methods showed a very good agreement of results. We observed the stimulation of glucose-induced insulin secretion from MIN6 cells by arginine, weaker stimulation by ornithine, but inhibitory effects of dopamine. Serotonin effects were either stimulatory or inhibitory, depending on the concentration of serotonin used. The results will require further investigation. The study also clearly revealed advantages of the IR binding assay that allows the measuring of a higher throughput of measured samples, with a broader range of concentrations than in the case of RIA kits. The IR binding assay can provide an alternative to standard RIA and ELISA assays for the determination of insulin levels in experimental samples and can be especially useful in scientific laboratories studying insulin production and secretion by ß cells and searching for new modulators of insulin secretion.


Assuntos
Secreção de Insulina , Insulina/análise , Insulina/metabolismo , Animais , Arginina/metabolismo , Linhagem Celular , Dopamina/metabolismo , Glucose/metabolismo , Humanos , Células Secretoras de Insulina/metabolismo , Ilhotas Pancreáticas/metabolismo , Camundongos , Ornitina/metabolismo , Radioimunoensaio/métodos , Ensaio Radioligante/métodos , Ratos , Ratos Wistar , Serotonina/metabolismo
8.
Nuklearmedizin ; 60(1): 38-46, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33535269

RESUMO

AIM: TSH-receptor (TSHR)-autoantibody (TRAb) is the serological hallmark of Graves' disease (GD). Recently, 3rd-generation radioimmunoassays (RIA) employing monoclonal TRAb such as M22 or T7 instead of TSH for the inhibition of human TRAb binding with solid-phase TSHR (coated tubes) have been introduced into laboratory routine. METHODS: As current assays typically employ a consecutive incubation of patient serum and labelled monoclonal TRAb, automation of TRAb RIA is a challenge. Thus, the assay procedure using human TSHR-coated tubes and the mouse monoclonal TRAb T7 was modified by combining both steps. The novel one-step method was compared with its corresponding consecutive 3rd-generation RIA by investigating 304 individuals encompassing 102 patients with active GD (GDa), 43 patients with GD after successful therapy (GDt), 31 with Hashimoto's disease (HD), 28 with non-autoimmune thyroid diseases (NAITD) and 100 healthy subjects (HS). RESULTS: With the new method, the incubation time was shortened by approximately one hour. Both 3rd-generation RIAs did not reveal a significantly different assay performance by comparing areas under the curve (AUC) with receiver operating characteristics curve analysis (AUC one-step: 0.94, AUC two-step: 0.96, p > 0.05, respectively). The two-step TRAb RIA demonstrated sensitivity and specificity values of 87.5 % and 96.2 %, respectively, whereas the one-step revealed 84.6 % and 96.2 %, respectively. CONCLUSION: One-step 3rd-generation RIA may be used for the reliable detection of TRAb. The shorter and easier assay design may improve its use and enable automation in routine nuclear medicine laboratories.


Assuntos
Autoanticorpos/imunologia , Radioimunoensaio , Receptores da Tireotropina/imunologia , Animais , Feminino , Masculino , Camundongos , Resultado do Tratamento
9.
Clin Biochem ; 90: 34-39, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33539807

RESUMO

BACKGROUND: Orexin-A and -B are neuropeptides involved in sleep-wake regulation. In human narcolepsy type 1, this cycle is disrupted due to loss of orexin-producing neurons in the hypothalamus. Cerebrospinal fluid (CSF) orexin-A measurement is used in the diagnosis of narcolepsy type 1. Currently available immunoassays may lack specificity for accurate orexin quantification. We developed and validated a liquid chromatography mass spectrometry assay (LC-MS/MS) for CSF orexin-A and B. METHODS: We used CSF samples from narcolepsy type 1 (n = 22) and type 2 (n = 6) and non-narcoleptic controls (n = 44). Stable isotope-labeled orexin-A and -B internal standards were added to samples before solid-phase extraction and quantification by LC-MS/MS. The samples were also assayed by commercial radioimmunoassay (RIA, n = 42) and enzymatic immunoassay (EIA, n = 72) kits. Stability of orexins in CSF was studied for 12 months. RESULTS: Our assay has a good sensitivity (10 pmol/L = 35 pg/mL) and a wide linear range (35-3500 pg/mL). Added orexin-A and -B were stable in CSF for 12 and 3 months, respectively, when frozen. The median orexin-A concentration in CSF from narcolepsy type 1 patients was <35 pg/mL (range < 35-131 pg/mL), which was lower than that in CSF from control individuals (98 pg/mL, range < 35-424 pg/mL). Orexin-A concentrations determined using our LC-MS/MS assay were five times lower than those measured with a commercial RIA. Orexin-B concentrations were undetectable. CONCLUSIONS: Orexin-A concentrations measured by our LC-MS/MS assay were lower in narcolepsy type 1 patients as compared to controls. RIA yielded on average higher concentrations than LC-MS/MS.


Assuntos
Narcolepsia/diagnóstico , Orexinas/líquido cefalorraquidiano , Espectrometria de Massas em Tandem/métodos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Cromatografia Líquida/métodos , Feminino , Humanos , Imunoensaio/métodos , Técnicas Imunoenzimáticas/métodos , Masculino , Pessoa de Meia-Idade , Narcolepsia/líquido cefalorraquidiano , Neurônios , Radioimunoensaio/métodos , Sensibilidade e Especificidade , Extração em Fase Sólida , Espectrometria de Massas em Tandem/normas , Adulto Jovem
13.
BJOG ; 128(4): 637-644, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32985075

RESUMO

OBJECTIVE: To investigate hair cortisol concentrations (HCC) monthly in pregnant women and to explore the effect of parity. DESIGN: Prospective cohort study from gestational week (GW) 26, at childbirth and postpartum. SETTING: An antenatal care clinic in southeast Sweden. SAMPLE: 390 pregnant women. METHODS: Cortisol was measured using radioimmunoassay in methanol extracts of ground hair samples. MAIN OUTCOME MEASURES: Hair cortisol concentrations. RESULTS: Both primi- and multiparae exhibited an increase in HCC throughout pregnancy. Primiparae had significantly higher HCC in the latter part of the last trimester compared with multiparae (1 month P = 0.003, 2 months P = 0.038). The use of psychotropic medication in the first trimester correlated to HCC postpartum (P < 0.001). HCC in GW 14-17 was associated with HCC in GW 18-21 (primiparae and multiparae, P < 0.001), GW 22-25 (primiparae P = 0.036, multiparae P = 0.033), and 2 months postpartum (primiparae P = 0.049). HCC in GW 18-21 was associated with GW 22-25 in both primiparae (P < 0.001) and multiparae (P < 0.001) as well as 2 months prior to childbirth among primiparae (<0.037). In general, all estimates of HCC in pregnancy and postpartum showed a significant association between HCC for a specific month and the HCC in the previous month (all P < 0.001), except for the association of HCC among primiparae in GW 22-25 and 3 months prior to childbirth. CONCLUSIONS: Increased cortisol concentrations in hair were observed during pregnancy, which decreased 3 months prior to childbirth in multiparae. The results indicate a quicker suppression of the hypothalamic CRH (corticotropin-releasing hormone) production by placenta CRH in multiparous women. TWEETABLE ABSTRACT: Multiparae have a quicker suppression of hypothalamic CRH production by placenta CRH during pregnancy compared to primiparae.


Assuntos
Cabelo/metabolismo , Hidrocortisona/metabolismo , Sistema Hipotálamo-Hipofisário/metabolismo , Paridade/fisiologia , Sistema Hipófise-Suprarrenal/metabolismo , Gravidez/metabolismo , Adolescente , Adulto , Biomarcadores/metabolismo , Feminino , Humanos , Modelos Lineares , Período Pós-Parto/metabolismo , Estudos Prospectivos , Radioimunoensaio , Adulto Jovem
14.
Appl Radiat Isot ; 168: 109526, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33316629

RESUMO

Radioimmunoassay (RIA) is an extremely specific and a highly sensitive type of immunoassay, but the long incubation time and generation of radioactive wastes limit the use of RIA. To complement these disadvantages of RIA, we suggest an advanced type of RIA based on a lab-on-a-chip (LOC) platform: µ-RIA. We designed a microfluidic chip for RIA and optimized the procedures of µ-RIA analysis, including surface modification, immunoreaction time, and washing. Based on the optimized conditions, we conducted a radioimmunoassay on the µ-RIA platform using a commercial RIA kit. With the µ-RIA, 5 min are adequate for analysis. The amount of reagent consumption is significantly reduced compared with conventional RIA. The standard curve with R2 = 0.9951 shows that we can quantitatively evaluate the amount of antigen present in unknown samples. We show the applicability of µ-RIA for the analysis of biomolecules and the potential of µ-RIA to be a novel platform for high-throughput analysis.


Assuntos
Ensaios de Triagem em Larga Escala/métodos , Dispositivos Lab-On-A-Chip , Radioimunoensaio/métodos , Dimetilpolisiloxanos , Desenho de Equipamento , Limite de Detecção , Radiometria/métodos
15.
Talanta ; 223(Pt 2): 121588, 2021 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-33298293

RESUMO

Measurement of antithyroglobulin antibodies (TgAb) is an inevitable laboratory tool in the management of thyroid gland diseases. Currently available immunoassays still have limitations underlying the necessity of the introduction of fast, sensitive, and label-free technologies. Our aim was to develop a method for TgAb measurement in human serum based on the quartz crystal microbalance (QCM) technology. We immobilized thyroglobulin on the surface of Attana LNB Carboxyl sensor chip®, prepared standard curve covering the range of 1-50000 kIU/L, and established optimal measurement conditions. The validation included determination of the detection limit (LOD), functional sensitivity, linearity, precision, as well as the comparison with the results of the radioimmunoassay (RIA). The LOD and functional sensitivity were 4.2 kIU/L and 4.7 kIU/L, respectively. The method was linear in the range of 20-10000 kIU/L. The regression equation for comparison with RIA was CQCM= 1.0056 • CRIA- 24.2778, whereby no significant proportional or systematic difference was present. There was a good agreement with RIA in the classification of patients according to the clinical significance of the results. The developed method has advantages over currently available assays in terms of better LOQ, a higher upper limit of linearity, and precision. The characteristics of the developed method unambiguously show that the application of the QCM biosensors offers a highly reliable novel approach for the measurement of TgAb in human serum.


Assuntos
Técnicas Biossensoriais , Técnicas de Microbalança de Cristal de Quartzo , Autoanticorpos , Humanos , Radioimunoensaio
16.
Clin Chim Acta ; 512: 106-111, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31790698

RESUMO

BACKGROUND: Progesterone is one of the female steroid hormones and plays an important role in the menstrual cycle and during pregnancy. It is especially important in preparing the uterus for the implantation of the blastocyst and maintaining pregnancy. The concentration in human serum is measured to determine the ovarian function retroactively and the cause of abortion in early pregnancy. METHODS: A quantification assay based on isotope dilution mass spectrometry to determine the concentration of progesterone in human serum is reported. Incorporated with 13C3-progesterone, serum samples were subjected to progesterone extraction and clean-up by C4 solid-phase-extraction columns and hexane-based liquid/liquid extraction, respectively. The cleaned-up serum samples were then subjected to MALDI-TOF mass spectrometry for the quantification of progesterone. RESULTS: Progesterone and the internal standard, 13C3-progesterone, were measured in the selected reaction monitoring mode for the transitions m/z 315.4 to 108.9 and m/z 318.4 to 111.9, respectively. We calculated the peak area ratio of progesterone to 13C3-progesterone. The progesterone concentration in human serum was calculated by substituting the peak area ratio into an isotope dilution calibration curve, and then compared with the radioimmunoassay. CONCLUSIONS: In the study, the concentrations of serum progesterone were measured, and the recovered progesterone concentration determined by the assay showed good robustness and consistency in comparison to the conventional radioimmunologic assay. We concluded that the 13C3-progesterone-based quantification assay is a robust method for the measurement of serum progesterone.


Assuntos
Isótopos , Progesterona , Feminino , Humanos , Técnicas de Diluição do Indicador , Radioimunoensaio , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz
17.
Elife ; 92020 12 11.
Artigo em Inglês | MEDLINE | ID: mdl-33306025

RESUMO

Single measurements of salivary and plasmatic oxytocin are used as indicators of the physiology of the oxytocin system. However, questions remain about whether they are sufficiently stable to provide valid trait markers of the physiology of the oxytocin system, and whether salivary oxytocin can accurately index its plasmatic concentrations. Using radioimmunoassay, we measured baseline plasmatic and/or salivary oxytocin from two independent datasets. We also administered exogenous oxytocin intravenously and intranasally in a triple dummy, within-subject, placebo-controlled design and compared baseline levels and the effects of routes of administration. Our findings question the use of single measurements of baseline oxytocin concentrations in saliva and plasma as valid trait markers of the physiology of the oxytocin system in humans. Salivary oxytocin is a weak surrogate for plasmatic oxytocin. The increases in salivary oxytocin observed after intranasal oxytocin most likely reflect unabsorbed peptide and should not be used to predict treatment effects.


Assuntos
Técnicas de Diagnóstico Endócrino , Sistema Endócrino/metabolismo , Ocitocina/sangue , Saliva/metabolismo , Administração Intranasal , Administração Intravenosa , Adolescente , Adulto , Biomarcadores/sangue , Humanos , Masculino , Ocitocina/administração & dosagem , Valor Preditivo dos Testes , Radioimunoensaio , Reprodutibilidade dos Testes , Fatores de Tempo , Adulto Jovem
19.
Proc Natl Acad Sci U S A ; 117(48): 30649-30660, 2020 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-33199596

RESUMO

Myasthenia gravis (MG) is a neuromuscular, autoimmune disease caused by autoantibodies that target postsynaptic proteins, primarily the acetylcholine receptor (AChR) and inhibit signaling at the neuromuscular junction. The majority of patients under 50 y with AChR autoantibody MG have thymic lymphofollicular hyperplasia. The MG thymus is a reservoir of plasma cells that secrete disease-causing AChR autoantibodies and although thymectomy improves clinical scores, many patients fail to achieve complete stable remission without additional immunosuppressive treatments. We speculate that thymus-associated B cells and plasma cells persist in the circulation after thymectomy and that their persistence could explain incomplete responses to resection. We studied patients enrolled in a randomized clinical trial and used complementary modalities of B cell repertoire sequencing to characterize the thymus B cell repertoire and identify B cell clones that resided in the thymus and circulation before and 12 mo after thymectomy. Thymus-associated B cell clones were detected in the circulation by both mRNA-based and genomic DNA-based sequencing. These antigen-experienced B cells persisted in the circulation after thymectomy. Many circulating thymus-associated B cell clones were inferred to have originated and initially matured in the thymus before emigration from the thymus to the circulation. The persistence of thymus-associated B cells correlated with less favorable changes in clinical symptom measures, steroid dose required to manage symptoms, and marginal changes in AChR autoantibody titer. This investigation indicates that the diminished clinical response to thymectomy is related to persistent circulating thymus-associated B cell clones.


Assuntos
Linfócitos B/metabolismo , Contagem de Linfócitos , Miastenia Gravis/sangue , Timo/metabolismo , Adolescente , Adulto , Autoanticorpos/imunologia , Linfócitos B/imunologia , Biomarcadores , Evolução Clonal/genética , Seleção Clonal Mediada por Antígeno , Suscetibilidade a Doenças , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Modelos Biológicos , Miastenia Gravis/etiologia , Radioimunoensaio , Receptores Colinérgicos/imunologia , Timectomia , Timo/citologia , Timo/imunologia , Recombinação V(D)J , Adulto Jovem
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