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1.
Hum Reprod ; 37(3): 411-427, 2022 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-34999823

RESUMO

STUDY QUESTION: Can non-invasive metabolic imaging via fluorescence lifetime imaging microscopy (FLIM) detect variations in metabolic profiles between discarded human blastocysts? SUMMARY ANSWER: FLIM revealed extensive variations in the metabolic state of discarded human blastocysts associated with blastocyst development over 36 h, the day after fertilization and blastocyst developmental stage, as well as metabolic heterogeneity within individual blastocysts. WHAT IS KNOWN ALREADY: Mammalian embryos undergo large changes in metabolism over the course of preimplantation development. Embryo metabolism has long been linked to embryo viability, suggesting its potential utility in ART to aid in selecting high quality embryos. However, the metabolism of human embryos remains poorly characterized due to a lack of non-invasive methods to measure their metabolic state. STUDY DESIGN, SIZE, DURATION: We conducted a prospective observational study. We used 215 morphologically normal human embryos from 137 patients that were discarded and donated for research under an approved institutional review board protocol. These embryos were imaged using metabolic imaging via FLIM to measure the autofluorescence of two central coenzymes, nicotinamide adenine (phosphate) dinucleotide (NAD(P)H) and flavine adenine dinucleotide (FAD+), which are essential for cellular respiration and glycolysis. PARTICIPANTS/MATERIALS, SETTING, METHODS: Here, we used non-invasive FLIM to measure the metabolic state of human blastocysts. We first studied spatial patterns in the metabolic state within human blastocysts and the association of the metabolic state of the whole blastocysts with stage of expansion, day of development since fertilization and morphology. We explored the sensitivity of this technique in detecting metabolic variations between blastocysts from the same patient and between patients. Next, we explored whether FLIM can quantitatively measure metabolic changes through human blastocyst expansion and hatching via time-lapse imaging. For all test conditions, the level of significance was set at P < 0.05 after correction for multiple comparisons using Benjamini-Hochberg's false discovery rate. MAIN RESULTS AND THE ROLE OF CHANCE: We found that FLIM is sensitive enough to detect significant metabolic differences between blastocysts. We found that metabolic variations between blastocyst are partially explained by both the time since fertilization and their developmental expansion stage (P < 0.05), but not their morphological grade. Substantial metabolic variations between blastocysts from the same patients remain, even after controlling for these factors. We also observe significant metabolic heterogeneity within individual blastocysts, including between the inner cell mass and the trophectoderm, and between the portions of hatching blastocysts within and without the zona pellucida (P < 0.05). And finally, we observed that the metabolic state of human blastocysts continuously varies over time. LIMITATIONS, REASONS FOR CAUTION: Although we observed significant variations in metabolic parameters, our data are taken from human blastocysts that were discarded and donated for research and we do not know their clinical outcome. Moreover, the embryos used in this study are a mixture of aneuploid, euploid and embryos of unknown ploidy. WIDER IMPLICATIONS OF THE FINDINGS: This work reveals novel aspects of the metabolism of human blastocysts and suggests that FLIM is a promising approach to assess embryo viability through non-invasive, quantitative measurements of their metabolism. These results further demonstrate that FLIM can provide biologically relevant information that may be valuable for the assessment of embryo quality. STUDY FUNDING/COMPETING INTEREST(S): Supported by the Blavatnik Biomedical Accelerator Grant at Harvard University. Becker and Hickl GmbH and Boston Electronics sponsored research with the loaning of equipment for FLIM. D.J.N. is an inventor on patent US20170039415A1. TRIAL REGISTRATION NUMBER: N/A.


Assuntos
Aneuploidia , Blastocisto , Adenina , Animais , Blastocisto/metabolismo , Técnicas de Cultura Embrionária/métodos , Desenvolvimento Embrionário , Humanos , Mamíferos , Microscopia de Fluorescência
2.
Chem Rev ; 117(14): 9524-9593, 2017 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-28517929

RESUMO

We review the literature on the use of computational methods to study the reactions between carbon dioxide and aqueous organic amines used to capture CO2 prior to storage, reuse, or sequestration. The focus is largely on the use of high level quantum chemical methods to study these reactions, although the review also summarizes research employing hybrid quantum mechanics/molecular mechanics methods and molecular dynamics. We critically review the effects of basis set size, quantum chemical method, solvent models, and other factors on the accuracy of calculations to provide guidance on the most appropriate methods, the expected performance, method limitations, and future needs and trends. The review also discusses experimental studies of amine-CO2 equilibria, kinetics, measurement and prediction of amine pKa values, and degradation reactions of aqueous organic amines. Computational simulations of carbon capture reaction mechanisms are also comprehensively described, and the relative merits of the zwitterion, termolecular, carbamic acid, and bicarbonate mechanisms are discussed in the context of computational and experimental studies. Computational methods will become an increasingly valuable and complementary adjunct to experiments for understanding mechanisms of amine-CO2 reactions and in the design of more efficient carbon capture agents with acceptable cost and toxicities.

3.
HPB (Oxford) ; 21(4): 413-418, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30293869

RESUMO

BACKGROUND: Neoadjuvant therapy (NT) for borderline resectable pancreatic cancer (BRPC) has evolved to include multi-agent regimens and chemoradiation. We report our experience and compare outcomes of initially resectable pancreatic cancer (IRPC) vs BRPC receiving NT across two eras of chemotherapy regimens. METHODS: Data were collected retrospectively on pancreaticoduodenectomy patients between January 2008 and October 2015. Outcomes and survival were compared based on patient, laboratory and treatment factors. RESULTS: 195 patients were included and 133 had IRPC and 62 BRPC. IRPC operations were shorter (449 min vs 520 min, p = 0.003), had less blood loss (663 ml vs 954 ml, p = 0.002) and involved fewer vascular resections (29% vs 76%, p = 0.002). The rate of R0 resection was identical (82%, p = 1) and the IRPC group had higher node-positive ratio (19.3% vs 7.2% p < 0.0001). 15 patients received a single agent regimen while 47 received multi-agent regimens with 90% receiving radiation.Survival was similar between BRPC and IRPC (log-rank p = 0.7). Histopathologic response (CAP grade 0 or 1) was not associated with survival (p = 0.13), but completion of ≥4 cycles of multi-agent pre-operative chemotherapy (p = 0.001) and complete response to NT (p = 0.04) were significant predictors of survival. CONCLUSIONS: BRPC patients treated with NT have similar morbidity and survival to their IRPC counterparts. Pathologic response and modern NT are associated with improved survival.


Assuntos
Adenocarcinoma/tratamento farmacológico , Adenocarcinoma/cirurgia , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias Pancreáticas/tratamento farmacológico , Neoplasias Pancreáticas/cirurgia , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Terapia Neoadjuvante , Pancreaticoduodenectomia , Estudos Retrospectivos , Análise de Sobrevida
4.
Environ Sci Technol ; 52(24): 14538-14546, 2018 12 18.
Artigo em Inglês | MEDLINE | ID: mdl-30481451

RESUMO

The high energy consumption of CO2 and absorbent regeneration is one of the most critical challenges facing commercial application of amine-based postcombustion CO2 capture. Here, we report a novel approach of metal-ion-mediated amine regeneration (MMAR) to advance the process of amine regeneration. MMAR uses the dual ability of amine to reversibly react with CO2 and reversibly complex with metal ions to reduce the enthalpy of the CO2 reaction, thus decrease the overall heat requirement for amine regeneration. To elucidate the mechanistic effects behind MMAR's ability to reduce CO2 reaction enthalpy, we developed a comprehensive chemical model describing the chemistry of Me(II)-monoethanolamine(MEA)-CO2-H2O system. The model was then validated using experimentally determined CO2 partial pressures via vapor-liquid equilibrium (VLE) measurements. We used the validated chemical model to gain insight into VLE behavior and solution chemistry, and to identify the specific changes in CO2 reaction enthalpy with and without metal ions. Two metals and five amines were evaluated in detail, which revealed that metal-ions with high complexation enthalpy and amines with large carbamate stability constant are preferred in MMAR, owing to their large reduction in reaction enthalpy and regeneration duty. We anticipate that MMAR could provide an alternative pathway to reducing the energy consumption of absorbent regeneration, ultimately making amine-based processes more technically and economically viable.


Assuntos
Aminas , Dióxido de Carbono , Íons , Metais , Termodinâmica
5.
Environ Sci Technol ; 52(2): 916-926, 2018 01 16.
Artigo em Inglês | MEDLINE | ID: mdl-29216429

RESUMO

In an effort to advance the understanding of multiamine based CO2 capture process absorbents, we report here the determination of the kinetic and equilibrium constants for a simple linear diamine N,N-dimethylethylenediamine (DMEDA) via stopped-flow spectrophotometric kinetic measurements and 1H/13C NMR titrations at 25.0 °C. From the kinetic data, the formation of monocarbamic acid (DMEDACOOH) from the reaction of DMEDA with CO2(aq) is the dominant reaction at high pH > 9.0 (k7 = 6.99 × 103 M-1·s-1). Below this pH, the formation of protonated monocarbamic acid (DMEDACOOH2) via the pathway involving DMEDAH+ and CO2(aq) becomes active and contributes to the kinetics despite the 107-fold decrease in the rate constant between the two pathways. 1H and 13C NMR spectra as a function of decreasing pH (increasing HCl concentration) at 25.0 °C have been evaluated here to confirm the protonation events in DMEDA. Calculations of the respective DMEDA nitrogen partial charges have also been undertaken to support the NMR protonation study. A comparison of the DMEDA kinetic constants with the corresponding data for piperazine (PZ) reveals that despite the larger basicity of DMEDA, the enhanced and superior kinetic performance of PZ with CO2(aq) above its predicted Bronsted reactivity is not observed in DMEDA.


Assuntos
Dióxido de Carbono , Diaminas , Etilenodiaminas , Cinética , Espectroscopia de Ressonância Magnética , Soluções
6.
Environ Sci Technol ; 51(12): 7169-7177, 2017 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-28562020

RESUMO

Novel absorbents with improved characteristics are required to reduce the existing cost and environmental barriers to deployment of large scale CO2 capture. Recently, bespoke absorbent molecules have been specifically designed for CO2 capture applications, and their fundamental properties and suitability for CO2 capture processes evaluated. From the study, two unique diamine molecules, 4-(2-hydroxyethylamino)piperidine (A4) and 1-(2-hydroxyethyl)-4-aminopiperidine (C4), were selected for further evaluation including thermodynamic characterization. The solubilities of CO2 in two diamine solutions with a mass fraction of 15% and 30% were measured at different temperatures (313.15-393.15 K) and CO2 partial pressures (up to 400 kPa) by thermostatic vapor-liquid equilibrium (VLE) stirred cell. The absorption enthalpies of reactions between diamines and CO2 were evaluated at different temperatures (313.15 and 333.15 K) using a CPA201 reaction calorimeter. The amine protonation constants and associated protonation enthalpies were determined by potentiometric titration. The interaction of CO2 with the diamine solutions was summarized and a simple mathematical model established that could make a preliminary but good prediction of the VLE and thermodynamic properties. Based on the analyses in this work, the two designer diamines A4 and C4 showed superior performance compared to amines typically used for CO2 capture and further research will be completed at larger scale.


Assuntos
Dióxido de Carbono , Diaminas , Piperidinas , Termodinâmica , Água
7.
J Oral Maxillofac Surg ; 75(6): 1151-1162, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28039006

RESUMO

PURPOSE: To show the feasibility of acquiring high-resolution sagittal ultrasound (US) images of the temporomandibular joint (TMJ). PATIENTS AND METHODS: We used commercially available US probes to assess the TMJ via a transoral soft tissue window to acquire sagittal images. Magnetic resonance imaging and clinical correlation were compared with the US findings by the consensus assessment of 2 of the senior investigators. RESULTS: The sample was composed of 10 TMJs (6 participants) with an age range of 34 to 71 years and a male-female ratio of 3:1. The condyle and subcondylar surface were visible in 10 of 10 joints (100%), the disc in 7 of 10 joints (70%), and the pterygoid muscles in 6 of 10 joints (60%). In the 5 joints with magnetic resonance correlation, disc position and configuration were confirmed in all cases. CONCLUSIONS: We show the first sagittal transoral sonograms of the TMJ disc and associated joint components.


Assuntos
Transtornos da Articulação Temporomandibular/diagnóstico por imagem , Articulação Temporomandibular/diagnóstico por imagem , Ultrassonografia/métodos , Adulto , Idoso , Estudos de Viabilidade , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Estudos Prospectivos , Ultrassonografia/instrumentação
8.
Environ Sci Technol ; 47(2): 1163-9, 2013 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-23190202

RESUMO

The present study reports (a) the determination of both the kinetic rate constants and equilibrium constants for the reaction of CO(2)(aq) with sterically hindered amines and (b) an attempt to elucidate a fundamental chemical understanding of the relationship between the amine structure and chemical properties of the amine that are relevant for postcombustion capture of CO(2) (PCC) applications. The reactions of CO(2)(aq) with a series of linear and methyl substituted primary amines and alkanolamines have been investigated using stopped-flow spectrophotometry and (1)H NMR measurements at 25.0 °C. The specific mechanism of absorption for each of the amines, that is CO(2) hydration and/or carbamate formation, is examined and, based on the mechanism, the kinetic and equilibrium constants for the formation of carbamic acid/carbamates, including protonation constants of the carbamate, are reported for amines that follow this pathway. A Brønsted correlation relating the kinetic rate constants and equilibrium constants for the formation of carbamic acid/carbamates with the protonation constant of the amine is reported. Such a relationship facilitates an understanding of the effects of steric and electronic properties of the amine toward its reactivity with CO(2). Further, such relationships can be used to guide the design of new amines with improved properties relevant to PCC applications.


Assuntos
Aminas/química , Dióxido de Carbono/isolamento & purificação , Adsorção , Carbamatos/química , Elétrons , Cinética , Espectroscopia de Ressonância Magnética , Prótons , Temperatura
9.
J Phys Chem A ; 117(5): 806-13, 2013 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-23286883

RESUMO

Piperazine (PZ) is widely recognized as a promising solvent for postcombustion capture (PCC) of carbon dioxide (CO(2)). In view of the highly conflicting data describing the kinetic reactions of CO(2)(aq) in piperazine solutions, the present study focuses on the identification of the chemical mechanism, specifically the kinetic pathways for CO(2)(aq) in piperazine solutions that form the mono- and dicarbamates, using the analysis of stopped-flow spectrophotometric kinetic measurements and (1)H NMR spectroscopic data at 25.0 °C. The complete set of rate and equilibrium constants for the kinetic pathways, including estimations for the protonation constants of the suite of piperazine carbamates/carbamic acids, is reported here using an extended kinetic model which incorporates all possible reactions for CO(2)(aq) in piperazine solutions. From the kinetic data determined in the present study, the reaction of CO(2)(aq) with free PZ was found to be the dominant reactive pathway. The superior reactivity of piperazine is confirmed in the kinetic rate constant determined for the formation of piperazine monocarbamic acid (k(7) = 2.43(3) × 10(4) M(-1) s(-1)), which is within the wide range of published values, making it one of the faster reacting amines. The corresponding equilibrium constant for the formation of the monocarbamic acid, K(7), markedly exceeds that of other monoamines. Kinetic and equilibrium constants for the remaining pathways indicate a minor contribution to the overall kinetics at high pH; however, these pathways may become more significant at higher CO(2) loadings and lower pH values where the concentrations of the reactive species are correspondingly higher.


Assuntos
Carbamatos/química , Dióxido de Carbono/química , Piperazinas/química , Temperatura , Estrutura Molecular , Piperazina , Soluções , Água/química
10.
BMC Plant Biol ; 12: 19, 2012 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-22330838

RESUMO

BACKGROUND: Fruit ripening is a complicated development process affected by a variety of external and internal cues. It is well established that calcium treatment delays fruit ripening and senescence. However, the underlying molecular mechanisms remain unclear. RESULTS: Previous studies have shown that calcium/calmodulin-regulated SR/CAMTAs are important for modulation of disease resistance, cold sensitivity and wounding response in vegetative tissues. To study the possible roles of this gene family in fruit development and ripening, we cloned seven SR/CAMTAs, designated as SlSRs, from tomato, a model fruit-bearing crop. All seven genes encode polypeptides with a conserved DNA-binding domain and a calmodulin-binding site. Calmodulin specifically binds to the putative targeting site in a calcium-dependent manner. All SlSRs were highly yet differentially expressed during fruit development and ripening. Most notably, the expression of SlSR2 was scarcely detected at the mature green and breaker stages, two critical stages of fruit development and ripening; and SlSR3L and SlSR4 were expressed exclusively in fruit tissues. During the developmental span from 10 to 50 days post anthesis, the expression profiles of all seven SlSRs were dramatically altered in ripening mutant rin compared with wildtype fruit. By contrast, only minor alterations were noted for ripening mutant nor and Nr fruit. In addition, ethylene treatment of mature green wildtype fruit transiently stimulated expression of all SlSRs within one to two hours. CONCLUSIONS: This study indicates that SlSR expression is influenced by both the Rin-mediated developmental network and ethylene signaling. The results suggest that calcium signaling is involved in the regulation of fruit development and ripening through calcium/calmodulin/SlSR interactions.


Assuntos
Proteínas de Ligação ao Cálcio/metabolismo , Proteínas de Ligação a Calmodulina/metabolismo , Frutas/crescimento & desenvolvimento , Família Multigênica , Solanum lycopersicum/genética , Sequência de Aminoácidos , Cálcio/metabolismo , Proteínas de Ligação ao Cálcio/genética , Calmodulina/metabolismo , Proteínas de Ligação a Calmodulina/genética , Clonagem Molecular , DNA de Plantas/genética , Etilenos/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Solanum lycopersicum/crescimento & desenvolvimento , Solanum lycopersicum/metabolismo , Dados de Sequência Molecular , Filogenia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Análise de Sequência de DNA , Transcriptoma
11.
Environ Sci Technol ; 46(13): 7422-9, 2012 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-22620675

RESUMO

The kinetics of the fast reversible carbamate formation reaction of CO(2)(aq) with a series of substituted cyclic secondary amines as well as the noncyclic secondary amine diethanolamine (DEA) has been investigated using the stopped-flow spectrophotometric technique at 25.0 °C. The kinetics of the slow parallel reversible reaction between HCO(3)(-) and amine has also been determined for a number of the amines by (1)H NMR spectroscopy at 25.0 °C. The rate of the reversible reactions and the equilibrium constants for the formation of carbamic acid/carbamate from the reactions of CO(2) and HCO(3)(-) with the amines are reported. In terms of the forward reaction of CO(2)(aq) with amine, the order with increasing rate constants is as follows: diethanolamine (DEA) < morpholine (MORP) ~ thiomorpholine (TMORP) < N-methylpiperazine (N-MPIPZ) < 4-piperidinemethanol (4-PIPDM) ~ piperidine (PIPD) < pyrrolidine (PYR). Both 2-piperidinemethanol (2-PIPDM) and 2-piperidineethanol (2-PIPDE) do not form carbamates. For the carbamate forming amines a Brønsted correlation relating the protonation constant of the amine to the carbamic acid formation rate and equilibrium constants at 25.0 °C has been established. The overall suitability of an amine for PCC in terms of kinetics and energy is discussed.


Assuntos
Aminas/química , Carbamatos/química , Dióxido de Carbono/química , Água/química , Etanolaminas/química , Cinética , Soluções , Espectrofotometria
12.
Jt Comm J Qual Patient Saf ; 38(7): 318-27, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22852192

RESUMO

BACKGROUND: In 2008 Henry Ford Health System launched its "No Harm Campaign," designed to integrate harm-reduction interventions into a systemwide initiative and, ultimately, to eliminate harm from the health care experience. METHODS: The No Harm Campaign aims to decrease harm events through enhancing the system's culture of safety by reporting and studying harm events, researching causality, identifying priorities, and redesigning care to eliminate harm. The campaign uses a comprehensive set of 27 measures for harm reduction, covering infection-, medication-, and procedure-related harm, as well as other types of harm, all of which are combined to comprise a unique global harm score. The campaign's objective is to reduce all-cause harm events systemwide by 50% by 2013. A wide range of communication processes, from systemwide leadership retreats to daily e-mail news sent to all employees and physicians, is used to promote the campaign. In addition, the campaign is on the intranet "Knowledge Wall," where monthly dashboards, meeting minutes, and best practices and the work of our teams and collaboratives are documented and shared. RESULTS: From 2008 through 2011, a 31% reduction in harm events and an 18% reduction in inpatient mortality occurred systemwide. DISCUSSION: Building infrastructure, creating a culture of safety, providing employee training and education, and improving work process design are critical to systemwide implementation of harm-reduction efforts. Key actions for ongoing success focus on leadership, disseminating performance, putting everyone to work, and stealing ideas through national and local collaborations. A financial model was created to assess cost-savings of reducing harm events; early results total nearly $10 million in four years.


Assuntos
Distinções e Prêmios , Modelos Organizacionais , Inovação Organizacional , Segurança do Paciente , Qualidade da Assistência à Saúde/organização & administração , Comunicação , Humanos , Relações Interprofissionais , Joint Commission on Accreditation of Healthcare Organizations , Liderança , Cultura Organizacional , Indicadores de Qualidade em Assistência à Saúde , Qualidade da Assistência à Saúde/economia , Gestão da Segurança/organização & administração , Estados Unidos
13.
Mycologia ; 104(3): 604-12, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22241612

RESUMO

A polygalacturonase (PG) isozyme was isolated from Penicillium solitum-decayed Anjou pear fruit and purified to homogeneity with a multistep process. Both gel filtration and cation exchange chromatography revealed a single PG activity peak, and analysis of the purified protein showed a single band with a molecular mass of 43 kDa, which is of fungal origin. The purified enzyme was active from pH 3.5-6, with an optimum at pH 4.5. PG activity was detectable 0-70 C with 50 C maximum. The purified isozyme was inhibited by the divalent cations Ca(2+), Mg(2+), Mn(2+) and Fe(2+) and analysis of enzymatic hydrolysis products revealed polygalacturonic acid monomers and oligomers. The purified enzyme has an isoelectric point of 5.3 and is not associated with a glycosylated protein. The PG isozyme macerated fruit tissue plugs in vitro and produced ~1.2-fold more soluble polyuronides from pear than from apple tissue, which further substantiates the role of PG in postharvest decay. Data from this study show for the first time that the purified PG produced in decayed Anjou pear by P. solitum, a weakly virulent fungus, is different from that PG produced by the same fungus in decayed apple.


Assuntos
Malus/microbiologia , Penicillium/enzimologia , Doenças das Plantas/microbiologia , Poligalacturonase/isolamento & purificação , Pyrus/microbiologia , Cátions Bivalentes/farmacologia , Eletroforese em Gel de Poliacrilamida , Frutas/microbiologia , Concentração de Íons de Hidrogênio , Hidrólise , Ponto Isoelétrico , Isoenzimas , Cinética , Peso Molecular , Poligalacturonase/química , Poligalacturonase/efeitos dos fármacos , Poligalacturonase/metabolismo , Temperatura , Ácidos Urônicos/análise , Ácidos Urônicos/metabolismo
14.
Food Res Int ; 162(Pt B): 112101, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36461341

RESUMO

Traditional method utilizes steam to pasteurize low-moisture ingredients like black peppercorns and almonds. Exposure to steam results in direct condensation on the product, unfavorable for a broader range of food ingredients such as dried herbs, fruits, and ground materials. Recent studies on the thermal inactivation of Salmonella in low-moisture foods suggest that the relative humidity in treatment chambers is an important factor, besides temperature, that determines the death rate of bacteria. Thus, thermal treatments with controlled high relative humidity can be an effective method to replace steam pasteurization. No condensation will occur when the products are preheated to above the dew-point temperature of the hot air in the treatment chamber, thus eliminating the need for post-treatment drying. To prove this concept, a special device was developed that preheated samples in a dry environment before exposing them to a controlled relative humidity (RH) at a high temperature. Using this device, the death rate of Salmonella Enteritidis PT30 (S. Enteritidis) in black peppercorns was determined at 80 °C and three different RH levels (60, 70, or 80 %) after the innoculated samples were heated to 78oC. The results indicate that the treatments at 80 °C and 80 % RH for 3 min, 70 % RH for 9 min, and 60 % RH for 25 min caused 5.4 ± 0.2, 6.2 ± 0.6, and 6.1 ± 1.0 log reductions, respectively. No condensation was observed on all of the treated samples. The moisture content (wet basis) of fully pasteurized (5-log reduction) black peppercorns at 60, 70, and 80 %RH reduced from 9.7 ± 0.4 % (untreated) to 8.7 ± 0.5 %, 9.2 ± 0.4 %, and 9.2 ± 0.2 %, respectively, indicating that post-drying is not required after the treatments. This study demonstrated the potential of using short-time high-RH treatments to control pathogens in low-moisture foods without the need for post-treatment drying.


Assuntos
Salmonella enteritidis , Vapor , Umidade , Dessecação , Temperatura Alta
15.
Elife ; 112022 07 27.
Artigo em Inglês | MEDLINE | ID: mdl-35894209

RESUMO

During cell division, kinetochore microtubules (KMTs) provide a physical linkage between the chromosomes and the rest of the spindle. KMTs in mammalian cells are organized into bundles, so-called kinetochore-fibers (k-fibers), but the ultrastructure of these fibers is currently not well characterized. Here, we show by large-scale electron tomography that each k-fiber in HeLa cells in metaphase is composed of approximately nine KMTs, only half of which reach the spindle pole. Our comprehensive reconstructions allowed us to analyze the three-dimensional (3D) morphology of k-fibers and their surrounding MTs in detail. We found that k-fibers exhibit remarkable variation in circumference and KMT density along their length, with the pole-proximal side showing a broadening. Extending our structural analysis then to other MTs in the spindle, we further observed that the association of KMTs with non-KMTs predominantly occurs in the spindle pole regions. Our 3D reconstructions have implications for KMT growth and k-fiber self-organization models as covered in a parallel publication applying complementary live-cell imaging in combination with biophysical modeling (Conway et al., 2022). Finally, we also introduce a new visualization tool allowing an interactive display of our 3D spindle data that will serve as a resource for further structural studies on mitosis in human cells.


Assuntos
Cinetocoros , Fuso Acromático , Animais , Cromossomos , Células HeLa , Humanos , Mamíferos , Metáfase , Microtúbulos/ultraestrutura , Fuso Acromático/ultraestrutura
16.
Elife ; 112022 07 25.
Artigo em Inglês | MEDLINE | ID: mdl-35876665

RESUMO

During eukaryotic cell division, chromosomes are linked to microtubules (MTs) in the spindle by a macromolecular complex called the kinetochore. The bound kinetochore microtubules (KMTs) are crucial to ensuring accurate chromosome segregation. Recent reconstructions by electron tomography (Kiewisz et al., 2022) captured the positions and configurations of every MT in human mitotic spindles, revealing that roughly half the KMTs in these spindles do not reach the pole. Here, we investigate the processes that give rise to this distribution of KMTs using a combination of analysis of large-scale electron tomography, photoconversion experiments, quantitative polarized light microscopy, and biophysical modeling. Our results indicate that in metaphase, KMTs grow away from the kinetochores along well-defined trajectories, with the speed of the KMT minus ends continually decreasing as the minus ends approach the pole, implying that longer KMTs grow more slowly than shorter KMTs. The locations of KMT minus ends, and the turnover and movements of tubulin in KMTs, are consistent with models in which KMTs predominately nucleate de novo at kinetochores in metaphase and are inconsistent with substantial numbers of non-KMTs being recruited to the kinetochore in metaphase. Taken together, this work leads to a mathematical model of the self-organization of kinetochore-fibers in human mitotic spindles.


Assuntos
Cinetocoros , Fuso Acromático , Segregação de Cromossomos , Cromossomos , Humanos , Metáfase , Microtúbulos/metabolismo , Mitose , Fuso Acromático/metabolismo
17.
Chest ; 161(2): 392-406, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-34364867

RESUMO

BACKGROUND: US hospitals have reported compliance with the SEP-1 quality measure to Medicare since 2015. Finding an association between compliance and outcomes is essential to gauge measure effectiveness. RESEARCH QUESTION: What is the association between compliance with SEP-1 and 30-day mortality among Medicare beneficiaries? STUDY DESIGN AND METHODS: Studying patient-level data reported to Medicare by 3,241 hospitals from October 1, 2015, to March 31, 2017, we used propensity score matching and a hierarchical general linear model (HGLM) to estimate the treatment effects associated with compliance with SEP-1. Compliance was defined as completion of all qualifying SEP-1 elements including lactate measurements, blood culture collection, broad-spectrum antibiotic administration, 30 mL/kg crystalloid fluid administration, application of vasopressors, and patient reassessment. The primary outcome was a change in 30-day mortality. Secondary outcomes included changes in length of stay. RESULTS: We completed two matches to evaluate population-level treatment effects. In standard match, 122,870 patients whose care was compliant were matched with the same number whose care was noncompliant. Compliance was associated with a reduction in 30-day mortality (21.81% vs 27.48%, respectively), yielding an absolute risk reduction (ARR) of 5.67% (95% CI, 5.33-6.00; P < .001). In stringent match, 107,016 patients whose care was compliant were matched with the same number whose care was noncompliant. Compliance was associated with a reduction in 30-day mortality (22.22% vs 26.28%, respectively), yielding an ARR of 4.06% (95% CI, 3.70-4.41; P < .001). At the subject level, our HGLM found compliance associated with lower 30-day risk-adjusted mortality (adjusted conditional OR, 0.829; 95% CI, 0.812-0.846; P < .001). Multiple elements correlated with lower mortality. Median length of stay was shorter among cases whose care was compliant (5 vs 6 days; interquartile range, 3-9 vs 4-10, respectively; P < .001). INTERPRETATION: Compliance with SEP-1 was associated with lower 30-day mortality. Rendering SEP-1 compliant care may reduce the incidence of avoidable deaths.


Assuntos
Fidelidade a Diretrizes , Pacotes de Assistência ao Paciente , Sepse/mortalidade , Sepse/terapia , Idoso , Feminino , Humanos , Tempo de Internação/estatística & dados numéricos , Masculino , Medicare , Pontuação de Propensão , Estados Unidos
18.
J Clin Invest ; 118(9): 3170-80, 2008 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-18704196

RESUMO

Iatrogenic tumor cell implantation within surgical wounds can compromise curative cancer surgery. Adhesion of cancer cells, in particular colon cancer cells, is stimulated by exposure to increased extracellular pressure through a cytoskeleton-dependent signaling mechanism requiring FAK, Src, Akt, and paxillin. Mechanical stimuli during tumor resection may therefore negatively impact patient outcome. We hypothesized that perioperative administration of colchicine, which prevents microtubule polymerization, could disrupt pressure-stimulated tumor cell adhesion to surgical wounds and enhance tumor-free survival. Ex vivo treatment of Co26 and Co51 colon cancer cells with colchicine inhibited pressure-stimulated cell adhesion to murine surgical wounds and blocked pressure-induced FAK and Akt phosphorylation. Surgical wound contamination with pressure-activated Co26 and Co51 cells significantly reduced tumor-free survival compared with contamination with tumor cells under ambient pressure. Mice treated with pressure-activated Co26 and Co51 cells from tumors preoperatively treated with colchicine in vivo displayed reduced surgical site implantation and significantly increased tumor-free survival compared with mice exposed to pressure-activated cells from tumors not pretreated with colchicine. Our data suggest that pressure activation of malignant cells promotes tumor development and impairs tumor-free survival and that perioperative colchicine administration or similar interventions may inhibit this effect.


Assuntos
Colchicina/farmacologia , Neoplasias Experimentais/tratamento farmacológico , Cicatrização/efeitos dos fármacos , Animais , Linhagem Celular Tumoral , Intervalo Livre de Doença , Proteína-Tirosina Quinases de Adesão Focal/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Transplante de Neoplasias , Neoplasias Experimentais/mortalidade , Paxilina/metabolismo , Fosforilação , Pressão , Proteínas Proto-Oncogênicas c-akt/metabolismo , Moduladores de Tubulina/farmacologia , Quinases da Família src/metabolismo
19.
J Phys Chem A ; 115(24): 6405-12, 2011 Jun 23.
Artigo em Inglês | MEDLINE | ID: mdl-21598925

RESUMO

The kinetics of the interactions of aqueous ammonia with aqueous carbon dioxide/carbonate species has been investigated using stopped-flow techniques by monitoring the pH changes via indicators. The reactions include the reversible formation of ammonium carbamate/carbamic acid. A complete reaction mechanism has been established, and the temperature dependence of all rate and equilibrium constants including the protonation constant of the amine between 15 and 45 °C are reported and analyzed in terms of Arrhenius, Eyring, and van't Hoff relationships.

20.
J Phys Chem A ; 115(50): 14340-9, 2011 Dec 22.
Artigo em Inglês | MEDLINE | ID: mdl-22035132

RESUMO

The temperature dependence of the reversible reaction between CO(2)(aq) and monoethanolamine (MEA) has been investigated using stopped-flow spectrophotometry by following the pH changes during the reactions with colored acid-base indicators. Multivariate global analysis of both the forward and backward kinetic measurements for the reaction of CO(2)(aq) with MEA yielded the rate and equilibrium constants, including the protonation constant of MEA carbamate, for the temperature range of 15-45 °C. Analysis of the rate and equilibrium constants in terms of the Arrhenius, Eyring, and van't Hoff relationships gave the relevant thermodynamic parameters. In addition, the rate and equilibrium constants for the slow, reversible reaction of bicarbonate with MEA are reported at 25.0 °C. At high pH, reactions of the amine with CO(2) and with bicarbonate are significant.

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