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1.
Gastroenterology ; 165(1): 149-161.e7, 2023 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-37004887

RESUMEN

BACKGROUND & AIMS: Tumor necrosis factor inhibitors, including infliximab and adalimumab, are a mainstay of pediatric Crohn's disease therapy; however, nonresponse and loss of response are common. As combination therapy with methotrexate may improve response, we performed a multicenter, randomized, double-blind, placebo-controlled pragmatic trial to compare tumor necrosis factor inhibitors with oral methotrexate to tumor necrosis factor inhibitor monotherapy. METHODS: Patients with pediatric Crohn's disease initiating infliximab or adalimumab were randomized in 1:1 allocation to methotrexate or placebo and followed for 12-36 months. The primary outcome was a composite indicator of treatment failure. Secondary outcomes included anti-drug antibodies and patient-reported outcomes of pain interference and fatigue. Adverse events (AEs) and serious AEs (SAEs) were collected. RESULTS: Of 297 participants (mean age, 13.9 years, 35% were female), 156 were assigned to methotrexate (110 infliximab initiators and 46 adalimumab initiators) and 141 to placebo (102 infliximab initiators and 39 adalimumab initiators). In the overall population, time to treatment failure did not differ by study arm (hazard ratio, 0.69; 95% CI, 0.45-1.05). Among infliximab initiators, there were no differences between combination and monotherapy (hazard ratio, 0.93; 95% CI, 0.55-1.56). Among adalimumab initiators, combination therapy was associated with longer time to treatment failure (hazard ratio, 0.40; 95% CI, 0.19-0.81). A trend toward lower anti-drug antibody development in the combination therapy arm was not significant (infliximab: odds ratio, 0.72; 95% CI, 0.49-1.07; adalimumab: odds ratio, 0.71; 95% CI, 0.24-2.07). No differences in patient-reported outcomes were observed. Combination therapy resulted in more AEs but fewer SAEs. CONCLUSIONS: Among adalimumab but not infliximab initiators, patients with pediatric Crohn's disease treated with methotrexate combination therapy experienced a 2-fold reduction in treatment failure with a tolerable safety profile. CLINICALTRIALS: gov, Number: NCT02772965.


Asunto(s)
Metotrexato , Inhibidores del Factor de Necrosis Tumoral , Niño , Humanos , Femenino , Adolescente , Masculino , Metotrexato/efectos adversos , Adalimumab/efectos adversos , Anticuerpos Monoclonales/efectos adversos , Infliximab/efectos adversos , Factor de Necrosis Tumoral alfa , Resultado del Tratamiento
2.
Rheumatol Int ; 44(2): 235-247, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-37999798

RESUMEN

Agricultural workers constitute two-thirds of the population of Low- and Middle-Income Countries (LMIC) and are at increased risk of developing musculoskeletal disorders (MSD) due to high-risk activities. This systematic review and meta-analysis aim to synthesise the prevalence, predictors, and outcomes of musculoskeletal pain amongst agricultural workers to identify priority areas for prevention and development of early interventions. This systematic review and meta-analysis included Studies published from the inception of global electronic databases until 30 September 2022 were included. Prevalence estimates for MSDs among agricultural workers aged over 18 years in LMIC were extracted. Narrative synthesis summarized study findings and pooled estimates for 12-month pain prevalence were calculated. 7502 potential studies were identified. 64 studies (68,684 participants from 23 countries) were included in the systematic review; 33 studies were included in the meta-analysis. Low back pain was the most widely investigated symptom. The 12-month pooled prevalence of low back pain was highest in Africa [61.96% (45.69-76.22)] compared to Asia [54.16% (47.76-60.50)] and South/Central America [28.52%(10.91-50.33)]. Narrative synthesis found associations between MSDs, particular activities including heavy lifting and repetitive movements, and outcomes including reduced productivity. MSDs are common in agriculture workers in LMIC. Global prevalence of low back pain in farmers, particularly in Africa, is greater than in previously reported global prevalence in the general population. This may be attributed to environmental factors and high-risk activities which could be targeted for prevention and early intervention strategies to support individuals, prevent disability, and reduce loss of productivity.


Asunto(s)
Dolor de la Región Lumbar , Enfermedades Musculoesqueléticas , Dolor Musculoesquelético , Enfermedades Profesionales , Adulto , Humanos , Países en Desarrollo , Agricultores , Dolor de la Región Lumbar/epidemiología , Enfermedades Musculoesqueléticas/epidemiología , Enfermedades Musculoesqueléticas/etiología , Dolor Musculoesquelético/epidemiología , Enfermedades Profesionales/epidemiología , Enfermedades Profesionales/complicaciones , Enfermedades Profesionales/prevención & control , Prevalencia
3.
J Infect Dis ; 228(6): 734-741, 2023 09 15.
Artículo en Inglés | MEDLINE | ID: mdl-37210741

RESUMEN

BACKGROUND: NVX-CoV2373 is an efficacious coronavirus disease 2019 (COVID-19) vaccine comprising full-length recombinant severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike (rS) glycoprotein and Matrix-M adjuvant. Phase 2 of a randomized, placebo-controlled, phase 1/2 trial in healthy adults (18-84 years of age) previously reported good safety/tolerability and robust humoral immunogenicity. METHODS: Participants were randomized to placebo or 1 or 2 doses of 5-µg or 25-µg rS with 50 µg Matrix-M adjuvant 21 days apart. CD4+ T-cell responses to SARS-CoV-2 intact S or pooled peptide stimulation (with ancestral or variant S sequences) were measured via enzyme-linked immunosorbent spot assay and intracellular cytokine staining. RESULTS: A clearly discernable spike antigen-specific CD4+ T-cell response was induced after 1 dose, but markedly enhanced after 2 doses. Counts and fold increases in cells producing Th1 cytokines exceeded those secreting Th2 cytokines, although both phenotypes were clearly present. Interferon-γ responses to rS were detected in 93.5% of 2-dose 5-µg recipients. A polyfunctional CD4+ T-cell response was cross-reactive and of equivalent magnitude to all tested variants, including Omicron BA.1/BA.5. CONCLUSIONS: NVX-CoV2373 elicits a moderately Th1-biased CD4+ T-cell response that is cross-reactive with ancestral and variant S proteins after 2 doses. CLINICAL TRIALS REGISTRATION: NCT04368988.


Asunto(s)
Linfocitos T CD4-Positivos , COVID-19 , Adulto , Humanos , COVID-19/prevención & control , SARS-CoV-2 , Glicoproteína de la Espiga del Coronavirus/genética , Citocinas , Adyuvantes Inmunológicos , Adyuvantes Farmacéuticos , Anticuerpos Antivirales
4.
Gen Dent ; 70(6): 52-58, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36288076

RESUMEN

Periodontal disease affects 42% of adults in the United States. Both the periodontal microbiome and the host immune inflammatory response may be influenced by overweight/obesity status. This retrospective analysis sought to determine the associations of periodontal disease parameters with body mass index (BMI) and obesity status in patients undergoing periodontal maintenance therapy. The records of 418 patients who were undergoing periodontal maintenance after periodontitis treatment were examined, and the patients' demographic characteristics (sex, age, and race/ethnicity), self-reported BMI, periodontal disease condition, number of sites with probing depth ≥ 4 mm, missing teeth, and sites with bleeding on probing (BOP) were recorded. Patients were determined to have active moderate to severe periodontitis if they presented with 2 or more sites in 2 different quadrants with clinical attachment loss ≥ 5 mm and probing depth ≥ 5 mm. Individuals were also categorized into 3 groups: underweight/normoweight, BMI < 25; overweight, BMI 25 ≤ 30; or obese, BMI ≥ 30. In the study population, BMI ranged from 16.827 to 51.389. The periodontitis status was not significantly associated with a BMI status of overweight (odds ratio [OR] = 1.388 [95% CI, 0.961- 2.006]) or obese (OR = 1.168 [95% CI, 0.77-1.757]). Female sex (OR = 0.561 [95% CI, 0.343-0.918]) and age (OR = 0.983 [95% CI, 0.967-0.999]) were negatively associated with active periodontitis status. Obese patients demonstrated significantly more sites with BOP than either underweight/normoweight or overweight patients, and a BMI indicating obesity was associated with increasing age (P < 0.001) and higher number of missing teeth (P = 0.0064). In a population of patients undergoing periodontal maintenance therapy, BMI was associated with age and missing teeth, and obese status was associated with a significantly higher number of sites with BOP.


Asunto(s)
Enfermedades Periodontales , Periodontitis , Pérdida de Diente , Adulto , Humanos , Femenino , Índice de Masa Corporal , Sobrepeso/complicaciones , Índice Periodontal , Estudios Retrospectivos , Delgadez , Periodontitis/complicaciones , Periodontitis/terapia , Obesidad/complicaciones , Enfermedades Periodontales/complicaciones , Pérdida de la Inserción Periodontal/complicaciones , Pérdida de la Inserción Periodontal/epidemiología
5.
PLoS Med ; 18(10): e1003769, 2021 10.
Artículo en Inglés | MEDLINE | ID: mdl-34597298

RESUMEN

BACKGROUND: NVX-CoV2373 is a recombinant severe acute respiratory coronavirus 2 (rSARS-CoV-2) nanoparticle vaccine composed of trimeric full-length SARS-CoV-2 spike glycoproteins and Matrix-M1 adjuvant. METHODS AND FINDINGS: The phase 2 component of our randomized, placebo-controlled, phase 1 to 2 trial was designed to identify which dosing regimen of NVX-CoV2373 should move forward into late-phase studies and was based on immunogenicity and safety data through Day 35 (14 days after the second dose). The trial was conducted at 9 sites in Australia and 8 sites in the United States. Participants in 2 age groups (aged 18 to 59 and 60 to 84 years) were randomly assigned to receive either 1 or 2 intramuscular doses of 5-µg or 25-µg NVX-CoV2373 or placebo, 21 days apart. Primary endpoints were immunoglobulin G (IgG) anti-spike protein response, 7-day solicited reactogenicity, and unsolicited adverse events. A key secondary endpoint was wild-type virus neutralizing antibody response. After enrollment, 1,288 participants were randomly assigned to 1 of 4 vaccine groups or placebo, with 1,283 participants administered at least 1 study treatment. Of these, 45% were older participants 60 to 84 years. Reactogenicity was predominantly mild to moderate in severity and of short duration (median <3 days) after first and second vaccination with NVX-CoV2373, with higher frequencies and intensity after second vaccination and with the higher dose. Reactogenicity occurred less frequently and was of lower intensity in older participants. Both 2-dose regimens of 5-µg and 25-µg NVX-CoV2373 induced robust immune responses in younger and older participants. For the 2-dose regimen of 5 µg, geometric mean titers (GMTs) for IgG anti-spike protein were 65,019 (95% confidence interval (CI) 55,485 to 76,192) and 28,137 (95% CI 21,617 to 36,623) EU/mL and for wild-type virus neutralizing antibody (with an inhibitory concentration of 50%-MN50%) were 2,201 (95% CI 1,343 to 3,608) and 981 (95% CI 560 to 1,717) titers for younger and older participants, respectively, with seroconversion rates of 100% in both age groups. Neutralizing antibody responses exceeded those seen in a panel of convalescent sera for both age groups. Study limitations include the relatively short duration of safety follow-up to date and current lack of immune persistence data beyond the primary vaccination regimen time point assessments, but these data will accumulate over time. CONCLUSIONS: The study confirmed the phase 1 findings that the 2-dose regimen of 5-µg NVX-CoV2373 is highly immunogenic and well tolerated in younger adults. In addition, in older adults, the 2-dose regimen of 5 µg was also well tolerated and showed sufficient immunogenicity to support its use in late-phase efficacy studies. TRIAL REGISTRATION: ClinicalTrials.gov NCT04368988.


Asunto(s)
Vacunas contra la COVID-19/administración & dosificación , COVID-19/prevención & control , Inmunogenicidad Vacunal , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Anticuerpos Neutralizantes/inmunología , Anticuerpos Antivirales/inmunología , Relación Dosis-Respuesta Inmunológica , Femenino , Humanos , Inmunoglobulina G/inmunología , Masculino , Persona de Mediana Edad , SARS-CoV-2/inmunología , Glicoproteína de la Espiga del Coronavirus/inmunología , Adulto Joven
6.
Analyst ; 145(8): 3148-3156, 2020 Apr 14.
Artículo en Inglés | MEDLINE | ID: mdl-32191233

RESUMEN

Continued interest in protein therapeutics has motivated the development of improved bioanalytical tools to support development programs. LC-MS offers specificity, sensitivity, and multiplexing capabilities without the need for target-specific reagents, making it a valuable alternative to ligand binding assays. Immunoaffinity purification (IP) and enzymatic digestion are critical, yet extensive and time-consuming components of the "gold standard" bottom-up approach to LC-MS-based protein quantitation. In the present work, commercially available technology, based on membrane-immobilized reagents in spin column and plate format, is applied to reduce IP and digestion times from hours to minutes. For a standard monoclonal antibody, the lower limit of quantitation was 0.1 ng µL-1 compared to 0.05 ng µL-1 for the standard method. A pharmacokinetics (PK) study dosing Herceptin in rat was analyzed by both the membrane and the standard method with a total sample processing time of 4 h and 20 h, respectively. The calculated concentrations at each time point agreed within 8% between both methods, and PK values including area under the curve (AUC), half-life (T1/2), mean residence time (MRT), clearance (CL), and volume of distribution (Vdss) agreed within 6% underscoring the utility of the membrane methodology for quantitative bioanalysis workflows.


Asunto(s)
Cromatografía de Afinidad/métodos , Enzimas Inmovilizadas/química , Membranas Artificiales , Trastuzumab/análisis , Secuencia de Aminoácidos , Animales , Masculino , Prueba de Estudio Conceptual , Proteolisis , Ratas Sprague-Dawley , Proteína Estafilocócica A/química , Factores de Tiempo , Trastuzumab/química , Trastuzumab/aislamiento & purificación , Trastuzumab/farmacocinética , Tripsina/química
10.
Adv Exp Med Biol ; 1140: 435-449, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31347063

RESUMEN

Advances in mass spectrometry, proteomics, protein bioanalytical approaches, and biochemistry have led to a rapid evolution and expansion in the area of mass spectrometry-based biomarker discovery and development. The last decade has also seen significant progress in establishing accepted definitions, guidelines, and criteria for the analytical validation, acceptance and qualification of biomarkers. These advances have coincided with a decreased return on investment for pharmaceutical research and development and an increasing need for better early decision making tools. Empowering development teams with tools to measure a therapeutic interventions impact on disease state and progression, measure target engagement and to confirm predicted pharmacodynamic effects is critical to efficient data-driven decision making. Appropriate implementation of a biomarker or a combination of biomarkers can enhance understanding of a drugs mechanism, facilitate effective translation from the preclinical to clinical space, enable early proof of concept and dose selection, and increases the efficiency of drug development. Here we will provide descriptions of the different classes of biomarkers that have utility in the drug development process as well as review specific, protein-centric, mass spectrometry-based approaches for the discovery of biomarkers and development of targeted assays to measure these markers in a selective and analytically precise manner.


Asunto(s)
Biomarcadores , Desarrollo de Medicamentos , Espectrometría de Masas , Proteómica
11.
J Transl Med ; 15(1): 258, 2017 Dec 19.
Artículo en Inglés | MEDLINE | ID: mdl-29258604

RESUMEN

BACKGROUND: Metabolic syndrome (MetS) is a highly prevalent condition that identifies individuals at risk for type 2 diabetes mellitus and atherosclerotic cardiovascular disease. Prevention of these diseases relies on early detection and intervention in order to preserve pancreatic ß-cells and arterial wall integrity. Yet, the clinical criteria for MetS are insensitive to the early-stage insulin resistance, inflammation, cholesterol and clotting factor abnormalities that characterize the progression toward type 2 diabetes and atherosclerosis. Here we report the discovery and initial characterization of an atypical new biomarker that detects these early conditions with just one measurement. METHODS: Water T2, measured in a few minutes using benchtop nuclear magnetic resonance relaxometry, is exquisitely sensitive to metabolic shifts in the blood proteome. In an observational cross-sectional study of 72 non-diabetic human subjects, the association of plasma and serum water T2 values with over 130 blood biomarkers was analyzed using bivariate, multivariate and logistic regression. RESULTS: Plasma and serum water T2 exhibited strong bivariate correlations with markers of insulin, lipids, inflammation, coagulation and electrolyte balance. After correcting for confounders, low water T2 values were independently and additively associated with fasting hyperinsulinemia, dyslipidemia and subclinical inflammation. Plasma water T2 exhibited 100% sensitivity and 87% specificity for detecting early insulin resistance in normoglycemic subjects, as defined by the McAuley Index. Sixteen normoglycemic subjects with early metabolic abnormalities (22% of the study population) were identified by low water T2 values. Thirteen of the 16 did not meet the harmonized clinical criteria for metabolic syndrome and would have been missed by conventional screening for diabetes risk. Low water T2 values were associated with increases in the mean concentrations of 6 of the 16 most abundant acute phase proteins and lipoproteins in plasma. CONCLUSIONS: Water T2 detects a constellation of early abnormalities associated with metabolic syndrome, providing a global view of an individual's metabolic health. It circumvents the pitfalls associated with fasting glucose and hemoglobin A1c and the limitations of the current clinical criteria for metabolic syndrome. Water T2 shows promise as an early, global and practical screening tool for the identification of individuals at risk for diabetes and atherosclerosis.


Asunto(s)
Biomarcadores/sangre , Espectroscopía de Resonancia Magnética , Síndrome Metabólico/sangre , Agua/metabolismo , Adulto , Anciano , Anciano de 80 o más Años , Proteínas Sanguíneas/metabolismo , Análisis por Conglomerados , Estudios Transversales , Femenino , Humanos , Modelos Logísticos , Masculino , Persona de Mediana Edad , Análisis de Componente Principal , Curva ROC , Sensibilidad y Especificidad , Adulto Joven
12.
Pediatr Res ; 81(4): 589-592, 2017 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-27911435

RESUMEN

BACKGROUND: The impact of secondhand marijuana smoke exposure on children is unknown. New methods allow detection of secondhand marijuana smoke in children. METHODS: We studied children ages 1 mo to 2 y hospitalized with bronchiolitis in Colorado from 2013 to 2015. Parents completed a survey, and urine samples were analyzed for cotinine using LC/MS/MS (limits of detection 0.03 ng/ml) and marijuana metabolites including COOH-THC (limits of detection 0.015 ng/ml). RESULTS: A total of 43 subjects had urine samples available for analysis. Most (77%) of the subjects were male, and 52% were less than 1 y of age. COOH-THC was detectable in 16% of the samples analyzed (THC+); the range in COOH-THC concentration was 0.03-1.5 ng/ml. Two subjects had levels >1 ng/ml. Exposure did not differ by gender or age. Non-white children had more exposure than white children (44 vs. 9%; P < 0.05). 56% of children with cotinine >2.0 ng/ml were THC+, compared with 7% of those with lower cotinine (P < 0.01). CONCLUSION: Metabolites of marijuana smoke can be detected in children; in this cohort, 16% were exposed. Detectable COOH-THC is more common in children with tobacco smoke exposure. More research is needed to assess the health impacts of marijuana smoke exposure on children and inform public health policy.


Asunto(s)
Biomarcadores/orina , Cotinina/orina , Fumar Marihuana/efectos adversos , Fumar Marihuana/orina , Humo/efectos adversos , Preescolar , Estudios de Cohortes , Colorado , Dronabinol/orina , Femenino , Hospitalización , Humanos , Lactante , Límite de Detección , Masculino , Padres , Factores Sexuales , Nicotiana/efectos adversos , Urinálisis
13.
Int Psychogeriatr ; 29(10): 1693-1699, 2017 10.
Artículo en Inglés | MEDLINE | ID: mdl-28629481

RESUMEN

BACKGROUND: This study explored the combined impact of depression and inflammation on memory functioning among Mexican-American adults and elders. METHODS: Data were analyzed from 381 participants of the Health and Aging Brain study among Latino Elders (HABLE). Fasting serum samples were collected and assayed in duplicate using electrochemiluminesce on the SECTOR Imager 2400A from Meso Scale Discovery. Positive DepE (depression endophenotype) was codified as any score >1 on a five-point scale based on the GDS-30. Inflammation was determined by TNFα levels and categorized by tertiles (1st, 2nd, 3rd). WMS-III LMI and LMII as well as CERAD were utilized as measures of memory. ANOVAs examined group differences between positive DepE and inflammation tertiles with neuropsychological scale scores as outcome variables. Logistic regressions were used to examine level of inflammation and DepE positive status on the risk for MCI. RESULTS: Positive DepE as well as higher inflammation were both independently found to be associated with lower memory scores. Among DepE positive, those who were high in inflammation (3rd tertile) were found to perform significantly worse on WMS-III LM I (F = 4.75, p = 0.003), WMS-III LM II (F = 8.18, p < 0.001), and CERAD List Learning (F = 17.37, p < 0.001) when compared to those low on inflammation (1st tertile). The combination of DepE positive and highest tertile of inflammation was associated with increased risk for MCI diagnosis (OR = 6.06; 95% CI = 3.9-11.2, p < 0.001). CONCLUSION: Presence of elevated inflammation and positive DepE scores increased risk for worse memory among Mexican-American older adults. Additionally, the combination of DepE and high inflammation was associated with increased risk for MCI diagnosis. This work suggests that depression and inflammation are independently associated with worse memory among Mexican-American adults and elders; however, the combination of both increases risk for poorer memory beyond either alone.


Asunto(s)
Disfunción Cognitiva/etnología , Depresión/etnología , Inflamación/etnología , Trastornos de la Memoria/etnología , Americanos Mexicanos , Anciano , Disfunción Cognitiva/complicaciones , Estudios de Cohortes , Depresión/complicaciones , Femenino , Humanos , Inflamación/complicaciones , Modelos Logísticos , Masculino , Trastornos de la Memoria/complicaciones , Persona de Mediana Edad , Pruebas Neuropsicológicas , Factores de Riesgo , Estados Unidos/epidemiología
14.
Nat Genet ; 40(9): 1056-8, 2008 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-18711365

RESUMEN

To identify susceptibility loci for bipolar disorder, we tested 1.8 million variants in 4,387 cases and 6,209 controls and identified a region of strong association (rs10994336, P = 9.1 x 10(-9)) in ANK3 (ankyrin G). We also found further support for the previously reported CACNA1C (alpha 1C subunit of the L-type voltage-gated calcium channel; combined P = 7.0 x 10(-8), rs1006737). Our results suggest that ion channelopathies may be involved in the pathogenesis of bipolar disorder.


Asunto(s)
Ancirinas/genética , Trastorno Bipolar/genética , Canales de Calcio Tipo L/genética , Estudio de Asociación del Genoma Completo , Cromosomas Humanos Par 10 , Cromosomas Humanos Par 12 , Cromosomas Humanos Par 15 , Predisposición Genética a la Enfermedad , Humanos , Modelos Logísticos , Polimorfismo de Nucleótido Simple
15.
J Proteome Res ; 15(8): 2739-48, 2016 08 05.
Artículo en Inglés | MEDLINE | ID: mdl-27425180

RESUMEN

Advances in liquid chromatography tandem mass spectrometry (LC-MS/MS) have permitted phosphoproteomic analysis on a grand scale, but ongoing challenges specifically associated with confident phosphate localization continue to motivate the development of new fragmentation techniques. In the present study, ultraviolet photodissociation (UVPD) at 193 nm is evaluated for the characterization of phosphopeptides in both positive and negative ion modes. Compared to the more standard higher energy collisional dissociation (HCD), UVPD provided more extensive fragmentation with improved phosphate retention on product ions. Negative mode UVPD showed particular merit for detecting and sequencing highly acidic phosphopeptides from alpha and beta casein, but was not as robust for larger scale analysis because of lower ionization efficiencies in the negative mode. HeLa and HCC70 cell lysates were analyzed by both UVPD and HCD. While HCD identified more phosphopeptides and proteins compared to UVPD, the unique matches from UVPD analysis could be combined with the HCD data set to improve the overall depth of coverage compared to either method alone.


Asunto(s)
Fosfopéptidos/análisis , Fotólisis/efectos de la radiación , Rayos Ultravioleta , Células HeLa , Humanos , Iones , Espectrometría de Masas/métodos , Fragmentos de Péptidos , Proteínas/análisis , Proteómica/métodos
16.
Anal Chem ; 88(22): 11037-11045, 2016 11 15.
Artículo en Inglés | MEDLINE | ID: mdl-27768275

RESUMEN

Tyrosine sulfation is an important post-translational modification but remains difficult to detect in biological samples owing to its low stoichiometric abundance and the lack of effective enrichment methods. In the present study, weak anion exchange (WAX) is evaluated for the enrichment of sulfopeptides that have been modified via carbamylation to convert all primary amines to less basic carbamates. The decrease in basicity enhanced the binding of carbamylated sulfopeptides to WAX resin relative to nonsulfated peptides. Upon elution and electrospray ionization in the negative mode, ultraviolet photodissociation (UVPD) was applied for peptide sequencing. Application of the method to a tryptic digest of bovine coagulation factor V resulted in identification of sulfation on tyrosine 1513.

17.
Trends Analyt Chem ; 83(A): 53-64, 2016 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-28003711

RESUMEN

Nuclear magnetic resonance relaxometry is a uniquely practical and versatile implementation of NMR technology. Because it does not depend on chemical shift resolution, it can be performed using low-field compact instruments deployed in atypical settings. Early relaxometry studies of human blood were focused on developing a diagnostic test for cancer. Those efforts were misplaced, as the measurements were not specific to cancer. However, important lessons were learned about the factors that drive the water longitudinal (T1) and transverse (T2) relaxation times. One key factor is the overall distribution of proteins and lipoproteins. Plasma water T2 can detect shifts in the blood proteome resulting from inflammation, insulin resistance and dyslipidemia. In whole blood, T2 is sensitive to hemoglobin content and oxygenation, although the latter can be suppressed by manipulating the static and applied magnetic fields. Current applications of compact NMR relaxometry include blood tests for candidiasis, hemostasis, malaria and insulin resistance.

19.
Mol Cell Proteomics ; 12(9): 2604-14, 2013 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-23695934

RESUMEN

The use of ultraviolet photodissociation (UVPD) for the activation and dissociation of peptide anions is evaluated for broader coverage of the proteome. To facilitate interpretation and assignment of the resulting UVPD mass spectra of peptide anions, the MassMatrix database search algorithm was modified to allow automated analysis of negative polarity MS/MS spectra. The new UVPD algorithms were developed based on the MassMatrix database search engine by adding specific fragmentation pathways for UVPD. The new UVPD fragmentation pathways in MassMatrix were rigorously and statistically optimized using two large data sets with high mass accuracy and high mass resolution for both MS(1) and MS(2) data acquired on an Orbitrap mass spectrometer for complex Halobacterium and HeLa proteome samples. Negative mode UVPD led to the identification of 3663 and 2350 peptides for the Halo and HeLa tryptic digests, respectively, corresponding to 655 and 645 peptides that were unique when compared with electron transfer dissociation (ETD), higher energy collision-induced dissociation, and collision-induced dissociation results for the same digests analyzed in the positive mode. In sum, 805 and 619 proteins were identified via UVPD for the Halobacterium and HeLa samples, respectively, with 49 and 50 unique proteins identified in contrast to the more conventional MS/MS methods. The algorithm also features automated charge determination for low mass accuracy data, precursor filtering (including intact charge-reduced peaks), and the ability to combine both positive and negative MS/MS spectra into a single search, and it is freely open to the public. The accuracy and specificity of the MassMatrix UVPD search algorithm was also assessed for low resolution, low mass accuracy data on a linear ion trap. Analysis of a known mixture of three mitogen-activated kinases yielded similar sequence coverage percentages for UVPD of peptide anions versus conventional collision-induced dissociation of peptide cations, and when these methods were combined into a single search, an increase of up to 13% sequence coverage was observed for the kinases. The ability to sequence peptide anions and cations in alternating scans in the same chromatographic run was also demonstrated. Because ETD has a significant bias toward identifying highly basic peptides, negative UVPD was used to improve the identification of the more acidic peptides in conjunction with positive ETD for the more basic species. In this case, tryptic peptides from the cytosolic section of HeLa cells were analyzed by polarity switching nanoLC-MS/MS utilizing ETD for cation sequencing and UVPD for anion sequencing. Relative to searching using ETD alone, positive/negative polarity switching significantly improved sequence coverages across identified proteins, resulting in a 33% increase in unique peptide identifications and more than twice the number of peptide spectral matches.


Asunto(s)
Cromatografía Liquida/métodos , Bases de Datos de Proteínas , Ensayos Analíticos de Alto Rendimiento , Proteoma/metabolismo , Proteómica/métodos , Espectrometría de Masas en Tándem/métodos , Rayos Ultravioleta , Algoritmos , Aniones , Proteínas Bacterianas/química , Proteínas Bacterianas/metabolismo , Halobacterium/metabolismo , Células HeLa , Humanos , Concentración de Iones de Hidrógeno , Peso Molecular , Péptidos/metabolismo , Proteoma/química , Curva ROC , Reproducibilidad de los Resultados , Análisis de Secuencia de Proteína
20.
Biochemistry ; 53(48): 7515-22, 2014 Dec 09.
Artículo en Inglés | MEDLINE | ID: mdl-25409529

RESUMEN

The functional properties of lipid-rich assemblies such as serum lipoproteins, cell membranes, and intracellular lipid droplets are modulated by the fluidity of the hydrocarbon chain environment. Existing methods for monitoring hydrocarbon chain fluidity include fluorescence, electron spin resonance, and nuclear magnetic resonance (NMR) spectroscopy; each possesses advantages and limitations. Here we introduce a new approach based on benchtop time-domain (1)H NMR relaxometry (TD-NMR). Unlike conventional NMR spectroscopy, TD-NMR does not rely on the chemical shift resolution made possible by homogeneous, high-field magnets and Fourier transforms. Rather, it focuses on a multiexponential analysis of the time decay signal. In this study, we investigated a series of single-phase fatty acid oils, which allowed us to correlate (1)H spin-spin relaxation time constants (T2) with experimental measures of sample fluidity, as obtained using a viscometer. Remarkably, benchtop TD-NMR at 40 MHz was able to resolve two to four T2 components in biologically relevant fatty acids, assigned to nanometer-scale domains in different segments of the hydrocarbon chain. The T2 values for each domain were exquisitely sensitive to hydrocarbon chain structure; the largest values were observed for pure fatty acids or mixtures with the highest cis-double bond content. Moreover, the T2 values for each domain exhibited positive linear correlations with fluidity. The TD-NMR T2 and fluidity measurements appear to be monitoring the same underlying phenomenon: variations in hydrocarbon chain packing. The results from this study validate the use of benchtop TD-NMR T2 as a nanofluidity meter and demonstrate its potential for probing nanofluidity in other systems of biological interest.


Asunto(s)
Ácidos Grasos/química , Espectroscopía de Resonancia Magnética/métodos , Ácidos Grasos Monoinsaturados/química , Hidrocarburos/química , Fluidez de la Membrana , Nanotecnología , Estereoisomerismo , Viscosidad
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