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1.
Cell Transplant ; 33: 9636897241243014, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38659255

RESUMO

Stress-induced islet graft loss during the peri-transplantation period reduces the efficacy of islet transplantation. In this prospective, randomized, double-blind clinical trial, we evaluated the safety and efficacy of 60 mg/kg human alpha-1 antitrypsin (AAT) or placebo infusion weekly for four doses beginning before surgery in chronic pancreatitis (CP) patients undergoing total pancreatectomy and islet autotransplantation (TP-IAT). Subjects were followed for 12 months post-TP-IAT. The dose of AAT was safe, as there was no difference in the types and severity of adverse events in participants from both groups. There were some biochemical signals of treatment effect with a higher oxygen consumption rate in AAT islets before transplantation and a lower serum C-peptide (an indicator of islet death) in the AAT group at 15 min after islet infusion. Findings per the statistical analysis plan using a modified intention to treat analysis showed no difference in the C-peptide area under the curve (AUC) following a mixed meal tolerance test at 12 months post-TP-IAT. There was no difference in the secondary and exploratory outcomes. Although AAT therapy did not show improvement in C-peptide AUC in this study, AAT therapy is safe in CP patients and there are experiences gained on optimal clinical trial design in this challenging disease.


Assuntos
Transplante das Ilhotas Pancreáticas , Pancreatectomia , Pancreatite Crônica , Transplante Autólogo , alfa 1-Antitripsina , Humanos , Transplante das Ilhotas Pancreáticas/métodos , Pancreatite Crônica/cirurgia , Pancreatite Crônica/terapia , alfa 1-Antitripsina/uso terapêutico , Masculino , Feminino , Pancreatectomia/métodos , Pessoa de Meia-Idade , Transplante Autólogo/métodos , Adulto , Método Duplo-Cego , Peptídeo C/sangue , Peptídeo C/metabolismo , Estudos Prospectivos
2.
Clin Transl Sci ; 16(8): 1352-1358, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37415296

RESUMO

The risk of severe adverse events related to thiopurine therapy can be reduced by personalizing dosing based on TPMT and NUDT15 genetic polymorphisms. However, the optimal genetic testing platform has not yet been established. In this study, we report on the TPMT and NUDT15 genotypes and phenotypes generated from 320 patients from a multicenter pediatric healthcare system using both Sanger sequencing and polymerase chain reaction genotyping (hereafter: genotyping) methods to determine the appropriateness of genotyping in our patient population. Sanger sequencing identified variant TPMT alleles including *3A (8, 3.2% of alleles), *3C (4, 1.6%), and *2 (1, 0.4%), and NUDT15 alleles including *2 (5, 3.6%) and *3 (1, 0.7%). For genotyped patients, variants identified in TPMT included *3A (12, 3.1%), *3C (4, 1%), *2 (2, 0.5%), and *8 (1, 0.25%), whereas NUDT15 included *4 (2, 1.9%) and *2 or *3 (1, 1%). Between Sanger sequencing and genotyping, no significant difference in allele, genotype, or phenotype frequency was identified for either TPMT or NUDT15. All patients who were tested using Sanger sequencing would have been accurately phenotyped for either TPMT (124/124), NUDT15 (69/69), or both genes (68/68) if they were assayed using the genotyping method. Considering 193 total TPMT and NUDT15 Sanger Sequencing tests reviewed, all tests would have resulted in an appropriate clinical recommendation if the test had instead been conducted using the comparison genotyping platforms. These results suggest that, in this study population, genotyping would be sufficient to provide accurate phenotype calls and clinical recommendations.


Assuntos
Azatioprina , Polimorfismo Genético , Humanos , Azatioprina/efeitos adversos , Testes Genéticos , Genótipo , Técnicas de Genotipagem
3.
Clin Transl Sci ; 15(10): 2479-2492, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-35899435

RESUMO

Opioid prescribing for postoperative pain management is challenging because of inter-patient variability in opioid response and concern about opioid addiction. Tramadol, hydrocodone, and codeine depend on the cytochrome P450 2D6 (CYP2D6) enzyme for formation of highly potent metabolites. Individuals with reduced or absent CYP2D6 activity (i.e., intermediate metabolizers [IMs] or poor metabolizers [PMs], respectively) have lower concentrations of potent opioid metabolites and potentially inadequate pain control. The primary objective of this prospective, multicenter, randomized pragmatic trial is to determine the effect of postoperative CYP2D6-guided opioid prescribing on pain control and opioid usage. Up to 2020 participants, age ≥8 years, scheduled to undergo a surgical procedure will be enrolled and randomized to immediate pharmacogenetic testing with clinical decision support (CDS) for CYP2D6 phenotype-guided postoperative pain management (intervention arm) or delayed testing without CDS (control arm). CDS is provided through medical record alerts and/or a pharmacist consult note. For IMs and PM in the intervention arm, CDS includes recommendations to avoid hydrocodone, tramadol, and codeine. Patient-reported pain-related outcomes are collected 10 days and 1, 3, and 6 months after surgery. The primary outcome, a composite of pain intensity and opioid usage at 10 days postsurgery, will be compared in the subgroup of IMs and PMs in the intervention (n = 152) versus the control (n = 152) arm. Secondary end points include prescription pain medication misuse scores and opioid persistence at 6 months. This trial will provide data on the clinical utility of CYP2D6 phenotype-guided opioid selection for improving postoperative pain control and reducing opioid-related risks.


Assuntos
Dor Aguda , Analgésicos Opioides , Dor Pós-Operatória , Humanos , Dor Aguda/diagnóstico , Dor Aguda/tratamento farmacológico , Analgésicos Opioides/administração & dosagem , Codeína/administração & dosagem , Citocromo P-450 CYP2D6/genética , Citocromo P-450 CYP2D6/metabolismo , Hidrocodona/administração & dosagem , Dor Pós-Operatória/diagnóstico , Dor Pós-Operatória/tratamento farmacológico , Padrões de Prática Médica , Estudos Prospectivos , Tramadol/administração & dosagem
4.
Pharmacy (Basel) ; 10(3)2022 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-35645326

RESUMO

Community service serves as a major aspect of pharmacy education; however, coronavirus disease 2019 (COVID-19) represented a significant disruption to student involvement. The College of Pharmacy student council, which serves as the local student government organization for the University of Florida College of Pharmacy, Jacksonville campus, developed a community service initiative to offer more consistent opportunities for students to participate in community service events, while adapting to COVID-19 restrictions. A retrospective, qualitative review of this initiative demonstrates the potential value of this model. Prior to this initiative, students relied on individual student organizations to provide service opportunities to their members. This excluded portions of the student body and led to sparse and inconsistent events, with limited variation in the types of service events available. Furthermore, de-centralized planning of service opportunities increased the difficulty of ensuring that COVID-19 safety restrictions were followed appropriately. This initiative resulted in 39 students logging over 200 service hours through nine events in the first seven months after its development. Despite the challenges presented by the COVID-19 pandemic, our centralized initiative serves as a model for improving community service involvement.

6.
Clin Pharmacol Ther ; 110(3): 677-687, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34231197

RESUMO

CYP2D6 genotype is increasingly being integrated into practice to guide prescribing of certain medications. The CYP2D6 drug metabolizing enzyme is susceptible to inhibition by concomitant drugs, which can lead to a clinical phenotype that is different from the genotype-based phenotype, a process referred to as phenoconversion. Phenoconversion is highly prevalent but not widely integrated into practice because of either limited experience on how to integrate or lack of knowledge that it has occurred. We built a calculator tool to help clinicians integrate a standardized method of assessing CYP2D6 phenoconversion into practice. During tool-building, we identified several clinical factors that need to be considered when implementing CYP2D6 phenoconversion into clinical practice. This tutorial shares the steps that the University of Florida Health Precision Medicine Program took to build the calculator tool and identified clinical factors to consider when implementing CYP2D6 phenoconversion in clinical practice.


Assuntos
Citocromo P-450 CYP2D6/genética , Genótipo , Humanos , Inativação Metabólica/genética , Farmacogenética/métodos , Fenótipo , Medicina de Precisão/métodos
7.
Clin Pharmacol Ther ; 109(3): 705-715, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-32897581

RESUMO

Genotyping for CYP2C19 no function alleles to guide antiplatelet therapy after percutaneous coronary intervention (PCI) improves clinical outcomes. Although results for the increased function CYP2C19*17 allele are also reported, its clinical relevance in this setting remains unclear. A collaboration across nine sites examined antiplatelet therapy prescribing and clinical outcomes in 3,342 patients after implementation of CYP2C19-guided antiplatelet therapy. Risk of major atherothrombotic and bleeding events over 12 months after PCI were compared across cytochrome P450 2C19 isozyme (CYP2C19) metabolizer phenotype and antiplatelet therapy groups by proportional hazards regression. Clopidogrel was prescribed to a similar proportion of CYP2C19 normal (84.5%), rapid (82.9%), and ultrarapid metabolizers (80.6%) (P = 0.360). Clopidogrel-treated normal metabolizers (20.4 events/100 patient-years; adjusted hazard ratio (HR) 1.00, 95% confidence interval (CI), 0.75-1.33, P = 0.993) and clopidogrel-treated rapid or ultrarapid metabolizers (19.1 events/100 patient-years; adjusted HR 0.95, 95% CI, 0.69-1.30, P = 0.734) exhibited no difference in major atherothrombotic events compared with patients treated with prasugrel or ticagrelor (17.6 events/100 patient-years). In contrast, clopidogrel-treated intermediate and poor metabolizers exhibited significantly higher atherothrombotic event risk compared with prasugrel/ticagrelor-treated patients (adjusted HR 1.56, 95% CI, 1.12-2.16, P = 0.008). When comparing clopidogrel-treated rapid or ultrarapid metabolizers to normal metabolizers, no difference in atherothrombotic (adjusted HR 0.97, 95% CI, 0.73-1.29, P = 0.808) or bleeding events (adjusted HR 1.34, 95% CI, 0.83-2.17, P = 0.224) were observed. In a real-world setting of genotype-guided antiplatelet therapy, the CYP2C19*17 allele did not significantly impact post-PCI prescribing decisions or clinical outcomes. These results suggest the CYP2C19 *1/*17 and *17/*17 genotypes have limited clinical utility to guide antiplatelet therapy after PCI.


Assuntos
Clopidogrel/uso terapêutico , Doença da Artéria Coronariana/terapia , Citocromo P-450 CYP2C19/genética , Intervenção Coronária Percutânea , Variantes Farmacogenômicos , Inibidores da Agregação Plaquetária/uso terapêutico , Trombose/prevenção & controle , Idoso , Clopidogrel/efeitos adversos , Clopidogrel/metabolismo , Doença da Artéria Coronariana/diagnóstico , Citocromo P-450 CYP2C19/metabolismo , Feminino , Genótipo , Hemorragia/induzido quimicamente , Hemorragia/genética , Humanos , Masculino , Pessoa de Meia-Idade , Intervenção Coronária Percutânea/efeitos adversos , Farmacogenética , Testes Farmacogenômicos , Fenótipo , Inibidores da Agregação Plaquetária/efeitos adversos , Inibidores da Agregação Plaquetária/metabolismo , Medicina de Precisão , Medição de Risco , Fatores de Risco , Trombose/etiologia , Trombose/genética , Fatores de Tempo , Resultado do Tratamento , Estados Unidos
8.
Pharmgenomics Pers Med ; 13: 217-226, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32765043

RESUMO

INTRODUCTION: Clinical adoption of genomic medicine has lagged behind the pace of scientific discovery. Practice-based resources can help overcome implementation challenges. METHODS: In 2015, the IGNITE (Implementing GeNomics In pracTicE) Network created an online genomic medicine implementation resource toolbox that was expanded in 2017 to incorporate the ability for users to create targeted implementation guides. This expansion was led by a multidisciplinary team that developed an evidence-based, structured framework for the guides, oversaw the technical process/build, and pilot tested the first guide, CYP2C19-Clopidogrel Testing Implementation. RESULTS: Sixty-five resources were collected from 12 institutions and categorized according to a seven-step implementation framework for the pilot CYP2C19-Clopidogrel Testing Implementation Guide. Five months after its launch, 96 CYP2C19-Clopidogrel Testing Implementation Guides had been created. Eighty percent of the resources most frequently selected by users were created by IGNITE to fill an identified resource gap. Resources most often included in guides were from the test reimbursement (22%), Implementation support gathering (22%), EHR integration (17%), and genetic testing workflow steps (17%). CONCLUSION: Lessons learned from this implementation guide development process provide insight for prioritizing development of future resources and support the value of collaborative efforts to create resources for genomic medicine implementation.

9.
J Clin Med ; 9(7)2020 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-32708920

RESUMO

Pharmacogenetic testing (PGT) is increasingly being used as a tool to guide clinical decisions. This article describes the development of an outpatient, pharmacist-led, pharmacogenetics consult clinic within internal medicine, its workflow, and early results, along with successes and challenges. A pharmacogenetics-trained pharmacist encouraged primary care physicians (PCPs) to refer patients who were experiencing side effects/ineffectiveness from certain antidepressants, opioids, and/or proton pump inhibitors. In clinic, the pharmacist confirmed the need for and ordered CYP2C19 and/or CYP2D6 testing, provided evidence-based pharmacogenetic recommendations to PCPs, and educated PCPs and patients on the results. Operational and clinical metrics were analyzed. In two years, 91 referred patients were seen in clinic (mean age 57, 67% women, 91% European-American). Of patients who received PGT, 77% had at least one CYP2C19 and/or CYP2D6 phenotype that would make conventional prescribing unfavorable. Recommendations suggested that physicians change a medication/dose for 59% of patients; excluding two patients lost to follow-up, 87% of recommendations were accepted. Challenges included PGT reimbursement and referral maintenance. High frequency of actionable results suggests physician education on who to refer was successful and illustrates the potential to reduce trial-and-error prescribing. High recommendation acceptance rate demonstrates the pharmacist's effectiveness in providing genotype-guided recommendations, emphasizing a successful pharmacist-physician collaboration.

10.
J Am Soc Mass Spectrom ; 31(7): 1491-1498, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-32510212

RESUMO

This is an invited Account and Perspective, providing observations and advice derived from a 40 year academic career that has included over 14 years' service as a program officer at the National Science Foundation (NSF) and 27 years of service as an Associate Editor of the Journal of the American Society for Mass Spectrometry. This work describes the program officer's perspective, with observations on what reviewers look for in proposals, and what are some of the more common, best avoided mistakes. Emphasis is on NSF guidelines, but many elements are general and intended for use by both proposal authors and reviewers.

11.
Clin Pharmacol Ther ; 108(3): 557-565, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32460360

RESUMO

There have been significant advancements in precision medicine and approaches to medication selection based on pharmacogenetic results. With the availability of direct-to-consumer genetic testing and growing awareness of genetic interindividual variability, patient demand for more precise, individually tailored drug regimens is increasing. The University of Florida (UF) Health Precision Medicine Program (PMP) was established in 2011 to improve integration of genomic data into clinical practice. In the ensuing years, the UF Health PMP has successfully implemented several single-gene tests to optimize the precision of medication prescribing across a variety of clinical settings. Most recently, the UF Health PMP launched a custom-designed pharmacogenetic panel, including pharmacogenes relevant to supportive care medications commonly prescribed to patients undergoing chemotherapy treatment, referred to as "GatorPGx." This tutorial provides guidance and information to institutions on how to transition from the implementation of single-gene pharmacogenetic testing to a preemptive panel-based testing approach. Here, we demonstrate application of the preemptive panel in the setting of an adult solid tumor oncology clinic. Importantly, the information included herein can be applied to other clinical practice settings.


Assuntos
Antineoplásicos/uso terapêutico , Perfilação da Expressão Gênica , Testes Farmacogenômicos , Variantes Farmacogenômicos , Medicina de Precisão , Antineoplásicos/efeitos adversos , Antineoplásicos/farmacocinética , Tomada de Decisão Clínica , Sistemas de Apoio a Decisões Clínicas , Técnicas de Apoio para a Decisão , Interações Medicamentosas , Aconselhamento Genético , Humanos , Farmacogenética , Polimedicação , Valor Preditivo dos Testes , Desenvolvimento de Programas , Avaliação de Programas e Projetos de Saúde
12.
J Am Soc Mass Spectrom ; 31(5): 1010-1014, 2020 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-32250114

RESUMO

This is an invited Account and Perspective, providing observations and advice on writing for review derived from a 40-year academic career that has included 27 years' service as an Associate Editor for the Journal of the American Society for Mass Spectrometry (JASMS) and nearly 14 years at the National Science Foundation. This work describes an Associate Editor's perspective. It offers observations on what editors and reviewers look for in manuscripts and some of the more common, best avoided mistakes. Emphasis is on JASMS guidelines, but many elements should be generally applicable and are intended for use by both authors and reviewers.

13.
Am J Speech Lang Pathol ; 27(1): 270-277, 2018 02 06.
Artigo em Inglês | MEDLINE | ID: mdl-29255849

RESUMO

Purpose: Accurate texture modifications to thin liquids are a critical aspect of patients' nutritional health and well-being. This study explored the use of 3 tools (2 distance- and 1 time-measuring devices) to characterize texture-modified liquids. The objectives were to use the tools to measure modified liquids, to determine if measurements differentiated nectar and honey levels of modification, and to compare measurements with other published reports. Method: We measured the flow distance of 33 prethickened water samples in centimeters (cm) using a line spread apparatus and a Bostwick Consistometer (Christison Particle Technologies). We selected a Zahn viscosity cup to measure the stream time of each prethickened liquid in seconds. Results: The 2 distance-measuring devices (line spread and Bostwick Consistometer) showed that thinner (nectar-thick) modifications spread or flowed a farther distance in comparison to thicker (honey-like) modifications. Testing with the line spread indicated that an average spread distance of 4.5 cm differentiated nectar-thick and honey-like consistencies. A flow distance of greater than 15 cm differentiated nectar from honey consistency measured with a Bostwick Consistometer. We were not successful in using the Zahn viscosity cup to determine the stream time of modified liquids. Conclusions: Two of the tools provided objective information about levels of liquid modification, which has implications for day-to-day preparation. Measurement tools that are accurate and easy to use have the potential to provide quick and dependable feedback to verify a prescribed level of liquid modification. Further efforts are needed to standardize the application of simple measurement tools in the management of patients who consume thickened liquids.


Assuntos
Bebidas/normas , Alimentos Formulados/normas , Teste de Materiais/métodos , Deglutição/fisiologia , Mel , Humanos , Néctar de Plantas , Viscosidade
14.
Int J Offender Ther Comp Criminol ; 61(3): 282-309, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26092108

RESUMO

Several general theories of crime were tested with path models on 293 female prisoners in a U.S. State prison. The theories tested included Social Bond and Control, Thrill/Risk Seeking, and a new attachment-based Developmental Dynamic Systems model. A large battery of different instruments ranging from measures of risk taking, to a crime addiction scale, to Childhood Adverse Events, to attachments and clinical issues were used. The older general theories of crime did not hold up well under the rigor of path modeling. The new dynamic systems model was supported that incorporated adverse childhood events leading to (a) peer crime, (b) crime addiction, and (c) a measure derived from the Attachment and Clinical Issues Questionnaire (ACIQ) that takes individual differences in attachments and clinical issues into account. The results were discussed in terms of new approaches to Research Defined Criteria of Diagnosis (RDoC) and new approaches to intervention.


Assuntos
Crime/psicologia , Identidade de Gênero , Prisioneiros/psicologia , Teoria Psicológica , Inquéritos e Questionários , Comportamento Exploratório , Feminino , Humanos , Controle Interno-Externo , Acontecimentos que Mudam a Vida , Modelos Psicológicos , Psicometria/estatística & dados numéricos , Transtorno Reativo de Vinculação na Infância/diagnóstico , Transtorno Reativo de Vinculação na Infância/psicologia , Teoria de Sistemas , Estados Unidos
15.
Anal Chem ; 86(1): 464-72, 2014 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-24308670

RESUMO

The evolution of droplet temperatures in an electrospray plume was measured via ratiometric fluorescence. Under typical operating conditions, droplet temperatures decrease ∼30 K over the first 5.0 mm along the spray axis, followed by a slight (∼2-3 K) rewarming. Experimental axial profiles (Z-axis) were fit by use of diffusion-controlled and surface-controlled evaporation models. Both models fit the experimental data well for the cooling portion of the spray (Pearson correlation coefficient R ≥ 0.994), but the surface-controlled model required unrealistic droplet radius values to obtain a good fit. In lateral profiles at a given Z near the emitter tip, temperatures are lower (by 3.0-10 K) in the periphery than on the spray axis. This behavior is consistent with the expected enrichment of the spray periphery with smaller droplets. At longer axial distances, lateral profiles were relatively flat. Droplet temperature as a function of axial displacement fell more rapidly at lower liquid flow rates, possibly attributable to changes in droplet size and/or velocity with flow rate.

16.
J Proteome Res ; 13(2): 692-701, 2014 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-24274857

RESUMO

Clostridium thermocellum has emerged as a leading bioenergy-relevant microbe due to its ability to solubilize cellulose into carbohydrates, mediated by multicomponent membrane-attached complexes termed cellulosomes. To probe microbial cellulose utilization rates, it is desirable to be able to measure the concentrations of saccharolytic enzymes and estimate the total amount of cellulosome present on a mass basis. Current cellulase determination methodologies involve labor-intensive purification procedures and only allow for indirect determination of abundance. We have developed a method using multiple reaction monitoring (MRM-MS) to simultaneously quantitate both enzymatic and structural components of the cellulosome protein complex in samples ranging in complexity from purified cellulosomes to whole cell lysates, as an alternative to a previously developed enzyme-linked immunosorbent assay (ELISA) method of cellulosome quantitation. The precision of the cellulosome mass concentration in technical replicates is better than 5% relative standard deviation for all samples, indicating high precision for determination of the mass concentration of cellulosome components.


Assuntos
Proteínas de Bactérias/química , Celulossomas/química , Clostridium thermocellum/química , Cromatografia Líquida de Alta Pressão , Clostridium thermocellum/enzimologia , Ensaio de Imunoadsorção Enzimática , Espectrometria de Massas/métodos
17.
Anal Chem ; 85(6): 3144-51, 2013 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-23406086

RESUMO

Post-translational modifications (PTMs) are known to play a significant role in many biological functions. The focus of this study is to optimize an integrated experimental/informatics approach to more confidently characterize the range of post-translational modifications of the cellulosome protein complex used by the bacterium Clostridium thermocellum to better understand how this protein machine is tuned for enzymatic cellulose solubilization. To enhance comprehensive characterization, the extracellular cellulosome proteins were analyzed using multiple proteolytic digests (trypsin, Lys-C, Glu-C) and multiple fragmentation techniques (collisionally activated dissociation, electron transfer dissociation, decision tree). As expected, peptide and protein identifications were increased by utilizing alternate proteases and fragmentation methods, in addition to the increase in protein sequence coverage. The complementarity of these experiments also allowed for a global exploration of PTMs associated with the cellulosome based upon a set of defined PTMs that included methylation, oxidation, acetylation, phosphorylation, and signal peptide cleavage. In these experiments, 85 modified peptides corresponding to 28 cellulosome proteins were identified. Many of these modifications were located in active cellulolytic or structural domains of the cellulosome proteins, suggesting a level of possible regulatory control of protein function in various cellulotyic conditions. The use of complementary proteolytic digestion/peptide fragmentation processes allowed for independent verification of PTMs in different experiments, thus leading to increased confidence in PTM identifications.


Assuntos
Celulose/metabolismo , Clostridium thermocellum/metabolismo , Líquido Extracelular/metabolismo , Fragmentos de Peptídeos/metabolismo , Processamento de Proteína Pós-Traducional/fisiologia , Proteólise , Sequência de Aminoácidos , Celulose/química , Celulose/genética , Clostridium thermocellum/química , Clostridium thermocellum/genética , Líquido Extracelular/química , Dados de Sequência Molecular , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/genética
18.
Anal Chem ; 84(17): 7547-54, 2012 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-22881719

RESUMO

Although qualitative and/or semiquantitative real-time monitoring of chemical reactions have been reported with a few mass spectrometric approaches, to our knowledge, no quantitative mass spectrometric approach has been reported so far to have a calibration valid up to molar concentrations as required by process control. This is mostly due to the absence of a practical solution that could well address the sample overloading issue. In this study, a novel autosampling flow injection analysis coupled with an atmospheric pressure chemical ionization mass spectrometry (FIA/APCI-MS) system, consisting of a 1 µL automatic internal sample injector, a postinjection splitter with 1:10 splitting ratio, and a detached APCI source connected to the mass spectrometer using a 4.5 in. long, 0.042 in. inner diameter (ID) stainless-steel capillary, was thus introduced. Using this system together with an optional FIA solvent modifier, e.g., 0.05% (v/v) isopropylamine, a linear quantitative calibration up to molar concentration has been achieved with 3.4-7.2% relative standard deviations (RSDs) for 4 replicates. As a result, quantitative real-time monitoring of a model reaction was successfully performed at the 1.63 M level. It is expected that this novel autosampling FIA/APCI-MS system can be used in quantitative real-time monitoring of a wide range of reactions under diverse reaction conditions.


Assuntos
Espectrometria de Massas por Ionização por Electrospray/métodos , Acrilonitrila/química , Pressão Atmosférica , Automação , Calibragem , Análise de Injeção de Fluxo , Fenetilaminas/análise , Propilaminas/química , Solventes/química , Espectrometria de Massas por Ionização por Electrospray/instrumentação , Espectrometria de Massas por Ionização por Electrospray/normas
19.
Rapid Commun Mass Spectrom ; 25(23): 3575-80, 2011 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-22095506

RESUMO

Batch slurry reactions are widely used in the industrial manufacturing of chemicals, pharmaceuticals, petrochemicals and polymers. However, onsite monitoring of batch slurry reactions is still not feasible in production plants due to the challenge in analyzing heterogeneous samples without complicated sample preparation procedures. In this study, direct analysis in real time mass spectrometry (DART-MS) has been evaluated for the onsite monitoring of a model batch slurry reaction. The results suggested that automation of the sampling process of DART-MS is important to achieve quantitative results. With a sampling technique of manual sample deposition on melting point capillaries followed by automatic sample introduction across the helium beam, relative standard deviation (RSD) of the protonated molecule signals from the reaction product of the model batch slurry reaction ranged from 6 to 30%. This RSD range is improved greatly over a sampling technique of manual sample deposition followed by manual sample introduction where the RSDs are up to 110%. Furthermore, with the semi-automated sampling approach, semi-quantitative analysis of slurry samples has been achieved. Better quantification is expected with a fully automated sampling approach.


Assuntos
Espectrometria de Massas/métodos , Indústria Química , Indústria Farmacêutica , Hélio/química , Íons/química , Compostos Orgânicos/análise , Compostos Orgânicos/química , Prótons , Reprodutibilidade dos Testes
20.
Anal Chem ; 81(24): 10080-8, 2009 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-19928901

RESUMO

A transient microenvironment mechanism (TMEM) is proposed to address matrix effects for direct analysis in real time (DART). When the DART gas stream is in contact with the sample, a transient microenvironment (TME), which can shield analytes from direct ionization, may be generated through the desorption of the matrix containing the analyte. The DART gas stream can directly ionize the matrix molecules, but the analytes will be ionized primarily through gas-phase ion/molecule reactions with the matrix ions. Experimental results showed that as little as 10 nL of liquid or 10 microg of solid was able to generate an efficient TME. Generated TMEs were able to control the ionization of an analyte below an analyte-to-matrix ratio that was dependent on the DART temperature and the boiling points of the analyte and matrix. TMEs generated by common solvents were studied in detail. The ionization of both polar and nonpolar compounds, present in a solvent or another analyte below a ratio of 1:100, were found to be mainly controlled by the generated TMEs at a DART temperature of 300 degrees C.

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