Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 151
Filtrar
Más filtros

Tipo del documento
Intervalo de año de publicación
1.
AAPS J ; 26(5): 89, 2024 Aug 02.
Artículo en Inglés | MEDLINE | ID: mdl-39150583

RESUMEN

A non-invasive capacitance instrument was embedded in the base of a vacuum-drying tray to monitor continuously the residual amount of solvent left in a pharmaceutical powder. Proof of concept was validated with Microcrystalline Cellulose laced with water, as well as water/acetone mixtures absorbed in a spray-dried Copovidone powder. To illustrate the role of impermeability of the base, we derive a model of vapor sorption that reveals the existence of a kinetic limit when solids are thinly spread, and a diffusion limit with greatly diminished effective diffusivity at large powder thickness. By monitoring the residual solvent content of powders, this new in situ technique offers advantages over indirect methods like mass spectrometry of vapor effluents, but without complications associated with probe fouling. To prescribe design guidelines and interpret signals, we model the electric field shed by the probe when a powder holds variable solvent mass fraction in the vertical direction.


Asunto(s)
Celulosa , Polvos , Solventes , Solventes/química , Vacio , Celulosa/química , Celulosa/análisis , Pirrolidinas/química , Pirrolidinas/análisis , Compuestos de Vinilo/química , Agua/química , Desecación/métodos , Acetona/análisis , Acetona/química , Difusión , Cinética
2.
Am J Kidney Dis ; 2024 Aug 08.
Artículo en Inglés | MEDLINE | ID: mdl-39127399

RESUMEN

RATIONALE & OBJECTIVE: Case-mix adjusted hemodialysis mortality has decreased since 1998. Many factors that influence mortality may have contributed to this trend and these associations may differ by continental region. We studied changes in hemodialysis facility practices over time and their potential role in mediating changes in patient survival. STUDY DESIGN: Observational prospective cohort study. SETTING & PARTICIPANTS: Adult hemodialysis patients treated in hemodialysis 500 facilities participating in the Dialysis Outcomes Practice Patterns Study (DOPPS) between 1999 and 2015 in the US, Japan, and 4 four European countries: Germany, Italy, Spain, and UK. PREDICTORS: Four practice measures at each facility: the percentages of patients with Kt/V>1.2, interdialytic weight gain [IDWG]<5.7%, phosphorus<6 mg/dL, and using AV fistulae. OUTCOMES: Patient survival. ANALYTICAL APPROACH: Mediation analyses, adjusted for case mix, were conducted using 3-year study phase as the exposure and facility practice measures as potential mediators. RESULTS: In Europe, we observed a 13% improvement in overall case-mix adjusted survival per decade. Trends in facility practice measures, especially Kt/V and phosphorus, explained 10% improvement in case-mix survival per decade, representing 77% (10% explained of 13% improvement) of the observed improvement. In Japan, 73% of the observed 12%/decade improvement in case-mix adjusted survival could be attributed to facility practices, especially Kt/V and IDWG. In the US, 56% of the observed 47%/decade improvement in case-mix adjusted survival could be attributed to facility practices, especially AV fistula use and phosphorus control. LIMITATIONS: Unmeasured changes in the characteristics of the patient population over this period may confound the observed associations. CONCLUSION: The improvements in adjusted hemodialysis patient survival in Europe, Japan, and the US from 1999 to 2015 can be largely explained by improvements in specific facility practices. Future changes in patient survival may be responsive to further evolution in the implementation of common clinical practices.

3.
Entropy (Basel) ; 26(4)2024 Mar 22.
Artículo en Inglés | MEDLINE | ID: mdl-38667830

RESUMEN

We derive the ab initio equilibrium statistical mechanics of the gas-liquid-solid contact angle on planar periodic, monodisperse, textured surfaces subject to electrowetting. To that end, we extend an earlier theory that predicts the advance or recession of the contact line amount to distinct first-order phase transitions of the filling state in the ensemble of nearby surface cavities. Upon calculating the individual capacitance of a cavity subject to the influence of its near neighbors, we show how hysteresis, which is manifested by different advancing and receding contact angles, is affected by electrowetting. The analysis reveals nine distinct regimes characterizing contact angle behavior, three of which arise only when a voltage is applied to the conductive liquid drop. As the square voltage is progressively increased, the theory elucidates how the drop occasionally undergoes regime transitions triggering jumps in the contact angle, possibly changing its hysteresis, or saturating it at a value weakly dependent on further voltage growth. To illustrate these phenomena and validate the theory, we confront its predictions with four data sets. A benefit of the theory is that it forsakes trial and error when designing textured surfaces with specific contact angle behavior.

4.
Proc Natl Acad Sci U S A ; 121(13): e2306763121, 2024 Mar 26.
Artículo en Inglés | MEDLINE | ID: mdl-38498711

RESUMEN

Lactate-proton symporter monocarboxylate transporter 1 (MCT1) facilitates lactic acid export from T cells. Here, we report that MCT1 is mandatory for the development of virus-specific CD8+ T cell memory. MCT1-deficient T cells were exposed to acute pneumovirus (pneumonia virus of mice, PVM) or persistent γ-herpesvirus (Murid herpesvirus 4, MuHV-4) infection. MCT1 was required for the expansion of virus-specific CD8+ T cells and the control of virus replication in the acute phase of infection. This situation prevented the subsequent development of virus-specific T cell memory, a necessary step in containing virus reactivation during γ-herpesvirus latency. Instead, persistent active infection drove virus-specific CD8+ T cells toward functional exhaustion, a phenotype typically seen in chronic viral infections. Mechanistically, MCT1 deficiency sequentially impaired lactic acid efflux from activated CD8+ T cells, caused an intracellular acidification inhibiting glycolysis, disrupted nucleotide synthesis in the upstream pentose phosphate pathway, and halted cell proliferation which, ultimately, promoted functional CD8+ T cell exhaustion instead of memory development. Taken together, our data demonstrate that MCT1 expression is mandatory for inducing T cell memory and controlling viral infection by CD8+ T cells.


Asunto(s)
Linfocitos T CD8-positivos , Transportadores de Ácidos Monocarboxílicos , Simportadores , Animales , Ratones , Transporte Biológico , Linfocitos T CD8-positivos/metabolismo , Ácido Láctico/metabolismo , Simportadores/genética , Simportadores/metabolismo , Transportadores de Ácidos Monocarboxílicos/genética , Transportadores de Ácidos Monocarboxílicos/metabolismo
5.
J AOAC Int ; 106(1): 228-238, 2022 Dec 22.
Artículo en Inglés | MEDLINE | ID: mdl-36124959

RESUMEN

BACKGROUND: Cyclizine (CYZ), a commonly used antiemetic drug, has two pharmacopeial toxic impurities, 1-methylpiperazine (MPZ) and diphenylmethanol (DPM). When CYZ parenteral formulations are administered intravenously, both impurities are poisonous, toxic, and harmful to the human body. OBJECTIVE: Cyclizine was determined along with its hazardous impurities MPZ and DPM by green multivariate calibration using UV-spectroscopic data. METHODS: Three multivariate algorithms were used to resolve and quantify overlapped spectral signals: principal component regression (PCR), partial least squares (PLS), and synergistic intervals partial least squares (siPLS). A concentration set containing 16 distinct combinations of CYZ, MPZ, and DPM was randomly prepared, and the absorbance values of the concentration set were determined using the 376 point-wavelength set with an interval of 0.2 nm between 200 and 275 nm. RESULTS: Good linear correlations were established for CYZ, MPZ, and DPM in the concentration ranges of 5.00-25.0, 0.50-2.50, and 0.50-2.50 µg/mL, respectively. The ideal spectral range and associated combinations were chosen based on the lowest root mean error of prediction (RMSEP) and correlation coefficient values (r). The siPLS approach performed better than the PCR and PLS models. The combination of four subintervals, 1, 3, 4, and 7, demonstrated the greatest effect, with RMSEP values of 0.0272, 0.0053, and 0.0315 for CYZ, MPZ, and DPM, respectively, and correlation coefficients of 0.9991, 0.9999, and 0.9997, in order. Various assessment tools were used to evaluate and measure the greenness profile of the established methods. The proposed methods were validated using internal and external validation sets. CONCLUSIONS: The three methods were effectively used to determine CYZ in its pure form and parenteral formulations, as well as its toxic impurities. The acquired results were compared statistically to those obtained using the reported HPLC method. HIGHLIGHTS: Cyclizine and its toxic impurities can be determined spectrophotometrically by using the three developed chemometric models.


Asunto(s)
Quimiometría , Ciclizina , Humanos , Espectrofotometría/métodos , Análisis de los Mínimos Cuadrados , Preparaciones Farmacéuticas , Calibración
6.
RSC Adv ; 12(22): 13896-13916, 2022 May 05.
Artículo en Inglés | MEDLINE | ID: mdl-35548387

RESUMEN

This work implements a combined experimental approach of analytical quality-by-design (AQbD) and green analytical chemistry (GAC) to develop an HPLC method for simultaneous determination of the two thalassemia drugs, deferasirox (DFX) and deferiprone (DFP), in biological fluid for the first time. This integration was designed to maximize efficiency and minimize environmental impacts, as well as energy and solvent consumption. To accomplish this goal, an analytical quality-by-design approach was performed, beginning with quality risk assessment and scouting analysis, followed by Placket-Burman design screening for five chromatographic parameters. Critical method parameters were thoroughly recognized and then optimized by using a two levels-three factors custom experimental design to evaluate the optimum conditions that achieved the highest resolution with acceptable peak symmetry within the shortest run time. The desirability function was used to define the optimal chromatographic conditions, and the optimal separation was achieved using an XBridge® HPLC RP-C18 (4.6 × 250 mm, 5 µm) column with ethanol : acidic water at pH 3.0 adjusted by phosphoric acid in the ratio of (70 : 30, v/v) as the mobile phase at a flow rate of 1 mL min-1 with UV detection at 225 nm at a temperature of 25 °C. Linearity was obtained over the concentration range of 0.30-20.00 µg mL-1 and 0.20-20.00 µg mL-1 for DFX and DFP, respectively, using 20.00 µg mL-1 ibuprofen (IBF) as an internal standard. The established method's greenness profile was evaluated and measured using various assessment tools, and the developed method was green. For the validation of the developed method, FDA recommendations were followed, and all the results obtained met the acceptance criteria. The suggested method was successfully used to study the pharmacokinetic parameters of DFX and DFP in rat plasma. Due to the substantial increase in bioavailability of the two iron chelating drugs, the results from this study strongly recommend their co-administration.

7.
J Fluoresc ; 32(3): 993-1003, 2022 May.
Artículo en Inglés | MEDLINE | ID: mdl-35239065

RESUMEN

Cyclizine (CYZ); an antiemetic compound; is widely misused for its euphoric or hallucinatory effects, either by oral or intravenous routes. The concomitant abuse of CYZ among addicted adolescents contributes to neuromuscular disorders that are life-threatening. Consequently, with the company of 1-Methylpiperazine (MPZ) and diphenylmethanol (DPM, Benzhydrol) as pharmacopoeia-reported CYZ impurities, a novel spectrofluorimetric assay for the detection of CYZ, has been established either in human plasma samples or in its parenteral formulation. The native fluorescence of CYZ has been investigated under various conditions. Different parameters affecting relative fluorescence intensity of CYZ including diluting solvent, surfactant, plasma protein solvent, and pH were studied and optimized. The linearity obtained between the fluorescence intensity at emission wavelength 350 nm after excitation at 244 nm and the corresponding CYZ concentrations was in the range 10-1000 ng/mL for measurement of CYZ either in pure form or in human plasma samples, with a appropriate correlation coefficient (r = 0.9999) and 3.10 ng/mL as the limit of detection and 9.41 ng/mL as the limit of quantitation. The suggested procedure was created and validated in accordance with ICH guidelines for quantification of CYZ either in its pure form or its dosage form, and FDA guidelines for the assay of CYZ in human plasma. Finally, in silico study and ADMET predictions were conducted for the studied drug impurities to estimate their pharmacokinetic behaviors. The results showed that both CYZ impurities have higher cellular permeability and maximum tolerated doses, DPM has higher BBB and CNS permeability than MPZ, while MPZ exceeds DPM in total clearance and volume of distribution.


Asunto(s)
Ciclizina , Plasma , Adolescente , Humanos , Solventes , Espectrometría de Fluorescencia/métodos , Tensoactivos
8.
Anal Chim Acta ; 1192: 339350, 2022 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-35057968

RESUMEN

Point of care (POC), also identified as on-site testing, has evolved as a rapid and accurate technique for drug of abuse screening and analysis. The aim of this work is to detect tropicamide (TPC) abuse in biological fluids; we selected rat plasma as example. We developed a disposal miniaturized, portable, green, and budget-friendly POC solid-state electrochemical sensor based on potentiometric transduction. To attain that, an innovative microfabricated electrode modified with conducting polymer poly(3-octylthiophene) (POT) has been placed on sensitized printed circuit board (PCB). A two-stage optimization process was implemented to develop the fabricated electrode. The first stage of the optimization process depends on screening various ionophores in order to enhance the sensor selectivity towards tropicamide. Copper nanoparticles exhibited the highest selectivity towards TPC. The second stage was utilizing a polymer as an ion-to-electron transducer layer between the copper nanoparticles impregnated ion sensing membrane and the microfabricated solid-contact ion-selective electrode. This polymer was added to boost the stability of the potential drift (1.2 mV/h) due to the hydrophobic behavior of the POT, which precludes the formation of an aqueous layer at the Cu electrode/polymeric membrane interface and improve the limit of detection (1.1 × 10-8 M). Nernstian potentiometric response was accomplished for TPC with a slope of 58.46 ± 0.43 mV/decade and E0 ∼ 189.39 ± 2.12 over the concentration range 1.0 × 10-7 to 1.0 × 10-2 M. The suggested sensor's intrinsic figure of merits include a quick response time (13 ± 2 s) and long life time (45 days). The proposed sensor has been successfully employed in the selective determination of TPC in pharmaceutical formulations, and biological fluids. When the results were compared to those of the official approach, there was no statistically significant difference. The Eco-Scale tool assessed and measured the greenness profile of the established method.


Asunto(s)
Nanopartículas , Tropicamida , Animales , Electrodos de Iones Selectos , Pruebas en el Punto de Atención , Potenciometría , Ratas
9.
Int J Mol Sci ; 22(13)2021 Jun 24.
Artículo en Inglés | MEDLINE | ID: mdl-34202553

RESUMEN

The cells of the immune system, particularly the T lymphocytes, have two main features that distinguish them from the cells of other tissues. They proliferate after activation and have the ability to move in tissues and organs. These characteristics compel them to develop metabolic plasticity in order to fulfil their immune function. This review focuses on the different known mechanisms that allow T cells to adapt their metabolism to the real-life circumstances they operate in, whether it is to exit quiescence, to differentiate into effector cells, or to participate in immune memory formation. Some of the metabolic adaptations to environmental variations that T cells are likely to undergo in their immune monitoring function are also discussed.


Asunto(s)
Metabolismo Energético , Linfocitos T/metabolismo , Inmunidad Adaptativa , Animales , Diferenciación Celular/inmunología , Humanos , Memoria Inmunológica , Activación de Linfocitos/inmunología , Linfocitos T/citología , Linfocitos T/inmunología , Linfocitos T Reguladores/inmunología , Linfocitos T Reguladores/metabolismo
11.
CorSalud ; 12(3): 283-291, jul.-set. 2020. tab, graf
Artículo en Español | LILACS | ID: biblio-1154033

RESUMEN

RESUMEN Introducción: Los cardiodesfibriladores mejoran la supervivencia de los pacientes con riesgo de muerte súbita cardíaca. Existen escasos datos en nuestro país acerca de su eficacia en el seguimiento. Objetivo: Describir la evolución en el seguimiento de los pacientes con primoimplante de un cardiodesfibrilador automático. Método: Estudio ambispectivo, longitudinal, en 47 pacientes con primoimplante de un cardiodesfibrilador en el período septiembre de 2007 a diciembre de 2016, con cierre el 31 de diciembre de 2017. La probabilidad acumulada de supervivencia se estimó a través de las curvas de Kaplan-Meier. Resultados: La edad media fue de 57 ± 14,6 años, con predominio del sexo masculino (74,5%) y la indicación en prevención secundaria (83%). Presentaron terapias apropiadas el 57,4% de los pacientes, terapias inapropiadas un 23,4%, proarritmia del cardiodesfibrilador un 14,9% y tormenta arrítmica el 12,8% de los pacientes. Las terapias apropiadas se relacionaron con la fracción de eyección ≤ 35% (p=0,022) y la edad (p=0,031). La supervivencia acumulada libre del primer evento a los cuatro años fue 34,7%. La mortalidad cardiovascular se relacionó con: existencia de cardiopatía estructural (p=0,044), fracción de eyección ≤ 35% (p<0,001), clase funcional III-IV (p=0,046), terapias apropiadas (p=0,014) y tormenta arrítmica (p=0,002). La supervivencia acumulada libre de mortalidad cardiovascular fue de 70,7% al cuarto año. Conclusiones: La supervivencia de los pacientes con cardiodesfibrilador es buena. La mortalidad se asocia a un mayor deterioro del estado cardiovascular y a las terapias del dispositivo.


ABSTRACT Introduction: Implantable cardioverter-defibrillators improve the survival of patients at risk of sudden cardiac death. There is relatively little data in our country about their follow-up effectiveness. Objective: To describe the outcome of patients with primo-implantation of an automatic cardioverter-defibrillator during follow-up. Methods: An ambispective longitudinal cohort study was conducted in 47 patients with primo-implantation of a cardioverter-defibrillator in the period September 2007 to December 2016, ending on December 31, 2017. The cumulative probability of survival was estimated through the Kaplan-Meier curves. Results: Mean age was 57 ± 14.6 years, with male predominance (74.5%) and indication in secondary prevention (83%). Adequate therapies were found in 57.4% of patients, inadequate therapies in 23.4%, implantable cardioverter-defibrillator proarrhythmia in 14.9% and arrhythmic storm in 12.8% of patients. Adequate therapies were related to an ejection fraction ≤ 35% (p=0.022) and age (p=0.031). Cumulative free survival from the first event at four years was 34,7%. Cardiovascular mortality was related to: existence of structural heart disease (p=0.044), ejection fraction ≤ 35% (p<0.001), functional class III-IV (p=0.046), adequate therapies (p=0.014) and arrhythmic storm (p=0.002). Cumulative free survival of cardiovascular mortality was 70.7% at the fourth year. Conclusions: The survival of patients with implantable cardioverter-defibrillator is satisfactory. Mortality is associated with further deterioration of cardiovascular status and with device therapies.


Asunto(s)
Muerte Súbita Cardíaca
12.
Bioanalysis ; 11(5): 349-364, 2019 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-30873855

RESUMEN

AIM: Two rapid and sensitive chromatographic methods have been developed and validated for simultaneous analysis of sofosbuvir (SOF) in rat plasma with two co-administered drugs, paracetamol (PAR) and DL-methionine (MET). MATERIALS & METHODS: The first method relied on using TLC-densitometry with a developing system consisted of chloroform: methanol: glacial acetic acid: formic acid in the ratio of 9.5: 1: 1.5: 0.5, by volume. The studied analytes and the internal standard naphazoline hydrochloride were scanned at 210 nm. The second method was HPLC method, whereas the analytes and the internal standard cinnarizine were separated on XTerra® HPLC RP C18 column using gradient elution mode and a mobile phase consisted of methanol: 0.1% aqueous TEA at pH 3 adjusted with orthophosphoric acid at 210 nm. RESULTS: The TLC-densitometry method showed linearity over concentration ranges of 160-3000 ng/band for SOF and PAR, 300-3000 ng/band for MET, but HPLC method was linear and validated over concentration ranges of 150-5000 ng/ml for SOF, 300-5000 ng/ml for both PAR and MET. CONCLUSION: All validation parameters met the acceptance criteria according to US FDA guidelines. Pharmacokinetic study was successfully applied and proved the possibility of co-administration of SOF with PAR and MET.


Asunto(s)
Acetaminofén/uso terapéutico , Analgésicos no Narcóticos/uso terapéutico , Antivirales/sangre , Cromatografía Liquida/métodos , Quimioterapia Combinada/métodos , Metionina/uso terapéutico , Sofosbuvir/sangre , Espectrometría de Masas en Tándem/métodos , Acetaminofén/farmacología , Analgésicos no Narcóticos/farmacología , Animales , Femenino , Metionina/farmacología , Ratas
13.
Elife ; 72018 06 18.
Artículo en Inglés | MEDLINE | ID: mdl-29911570

RESUMEN

Energy metabolism is essential for T cell function. However, how persistent antigenic stimulation affects T cell metabolism is unknown. Here, we report that long-term in vivo antigenic exposure induced a specific deficit in numerous metabolic enzymes. Accordingly, T cells exhibited low basal glycolytic flux and limited respiratory capacity. Strikingly, blockade of inhibitory receptor PD-1 stimulated the production of IFNγ in chronic T cells, but failed to shift their metabolism towards aerobic glycolysis, as observed in effector T cells. Instead, chronic T cells appeared to rely on oxidative phosphorylation (OXPHOS) and fatty acid oxidation (FAO) to produce ATP for IFNγ synthesis. Check-point blockade, however, increased mitochondrial production of superoxide and reduced viability and effector function. Thus, in the absence of a glycolytic switch, PD-1-mediated inhibition appears essential for limiting oxidative metabolism linked to effector function in chronic T cells, thereby promoting survival and functional fitness.


Asunto(s)
Antígeno B7-H1/genética , Linaje de la Célula/inmunología , Interferón gamma/genética , Receptor de Muerte Celular Programada 1/genética , Linfocitos T/inmunología , Adenosina Trifosfato/antagonistas & inhibidores , Adenosina Trifosfato/biosíntesis , Animales , Anticuerpos Monoclonales/farmacología , Antimetabolitos Antineoplásicos/farmacología , Antígeno B7-H1/inmunología , Linaje de la Célula/efectos de los fármacos , Linaje de la Célula/genética , Proteínas de Unión al ADN/deficiencia , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/inmunología , Diazooxonorleucina/farmacología , Compuestos Epoxi/farmacología , Perfilación de la Expresión Génica , Regulación de la Expresión Génica , Glucólisis/efectos de los fármacos , Interferón gamma/antagonistas & inhibidores , Interferón gamma/inmunología , Subunidad gamma Común de Receptores de Interleucina/deficiencia , Subunidad gamma Común de Receptores de Interleucina/genética , Subunidad gamma Común de Receptores de Interleucina/inmunología , Activación de Linfocitos , Masculino , Ratones , Ratones Endogámicos BALB C , Ratones Noqueados , Oligomicinas/farmacología , Fosforilación Oxidativa/efectos de los fármacos , Receptor de Muerte Celular Programada 1/antagonistas & inhibidores , Receptor de Muerte Celular Programada 1/inmunología , Receptores de Antígenos de Linfocitos T/genética , Receptores de Antígenos de Linfocitos T/inmunología , Transducción de Señal , Linfocitos T/citología , Linfocitos T/efectos de los fármacos , Linfocitos T/trasplante , Trasplante Homólogo
14.
Environ Sci Pollut Res Int ; 25(2): 1439-1447, 2018 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-29090444

RESUMEN

Rotating disk membrane (RDM) module with ultrafiltration (UF) was an effective alternative method to treat alfalfa wastewater and realize protein recovery and agricultural irrigation water production. A scientific investigation has been conducted to comprehend the effect of operation conditions (feed flow rate, shear rate, transmembrane pressure (TMP), and temperature) on alfalfa wastewater treatment with RDM-UF by central composite response surface methodology (CCRSM). First, the filtration behaviors of three types of UF membranes (PES20, UH030P, and PES50) were studied to select the optimized membrane (UH030P). Then, the effects and interactions of four operation conditions were studied and fitting models were established, while data on pollution reduction and protein recovery, membrane fouling behavior, and energy cost evaluation were collected. Furthermore, the optimized operation conditions calculated by CCRSM were Q = 60 L h-1, γ = 220 × 103 s-1, TMP = 5.61 bar, and T = 25 °C. In addition, the concentration test was conducted with these parameters. This work may contribute to the potential application of RDM for membrane wastewater treatment. Graphical abstract Schematic diagram of UF process for alfalfa wastewater treatment and resource recovery.


Asunto(s)
Medicago sativa , Ultrafiltración , Aguas Residuales , Purificación del Agua , Membranas Artificiales , Presión , Ultrafiltración/métodos , Eliminación de Residuos Líquidos/métodos , Purificación del Agua/métodos
15.
J Chromatogr Sci ; 55(9): 961-968, 2017 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-29048492

RESUMEN

Two accurate, precise and highly selective stability-indicating methods were adopted for simultaneous determination of benztropine mesylate (BNZ) in presence of its hepatotoxic and carcinogenic degradation product, benzophenone (BPH) either in pure form or in the pharmaceutical formulation without any preliminary separation steps. The first method is a thin layer chromatography (TLC)-densitometric method that depended on separation of BNZ from its degradate on TLC aluminum plates precoated with silica gel 60 F254 as the stationary phase using a developing system consisted of hexane:methylene chloride:triethylamine (5:5:0.6, by volume) and scanning the separated bands at 235 nm. Linear regression analysis data for the calibration plots of BNZ and BPH showed perfect linear relationships over the concentration range of 1.5-10 and 1-10 µg band-1, respectively. The second method is (UPLC) method, at which the mixture was separated on a reversed phase C8 analytical column (1.9 µm ps, 50 mm × 2.1 i.d.) using a mobile phase of acetonitrile: aqueous sodium dodecyl sulfate (50:50, v/v) Adjusted to pH = 3 with phosphoric acid, at a flow rate of 0.5 mL min-1. Quantification was achieved at 210 nm based on peak area and linear calibration curves over the concentration ranges of (20-200 µg mL-1) and (5-50 µg mL-1) for BNZ and BPH, respectively, were obtained. The investigated methods were successfully applied to available dosage form and method validation has been carried out. The results obtained by applying the proposed methods were statistically analyzed and compared with those obtained by reported one and no significant differences were obtained regarding both accuracy and precision.


Asunto(s)
Benzotropina/análisis , Benzotropina/química , Cromatografía Líquida de Alta Presión/métodos , Cromatografía en Capa Delgada/métodos , Carcinógenos/análisis , Carcinógenos/química , Densitometría/métodos , Estabilidad de Medicamentos , Límite de Detección , Modelos Lineales , Reproducibilidad de los Resultados
16.
Phys Rev E ; 95(3-1): 032804, 2017 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-28415366

RESUMEN

We outline a statistical mechanics of the triple gas-solid-liquid contact line on a rough plane. The analysis regards the neighborhood of the line as a solid dotted with cavities. It adopts the simplest mean-field statistical mechanics, in which each cavity is either full or empty, while being connected to near neighbors by thin necks. The theory predicts equilibrium angles for advance and recession in terms of the Young contact angle and the joint statistical distribution of two quantifiable geometrical parameters representing specific neck cross-section and specific cavity opening. It attributes contact angle hysteresis to first-order phase transitions among adjacent cavities, as they collectively imbibe or reject liquid. It also calculates the potential energy barriers that hysteresis erects against overcoming contact line pinning. By determining whether the phase transitions can release latent energy, this ab initio analysis distinguishes six regimes, including two metastable recession states. We compare predictions with data for superhydrophobia on microscopic rods; for hysteresis in the "Wenzel state"; and for variations of the advancing contact angle with surface energies of the liquid.

17.
Eur J Immunol ; 46(7): 1574-82, 2016 07.
Artículo en Inglés | MEDLINE | ID: mdl-27271222

RESUMEN

T-cell metabolism is central to the shaping of a successful immune response. However, there are pathological situations where T cells are rendered dysfunctional and incapable of eliminating infected or transformed cells. Here, we review the current knowledge on T-cell metabolism and how persistent antigenic stimulation, in the form of cancer and chronic viral infection, modifies both metabolic and functional pathways in T cells.


Asunto(s)
Reprogramación Celular/inmunología , Metabolismo Energético/inmunología , Activación de Linfocitos/inmunología , Subgrupos de Linfocitos T/inmunología , Subgrupos de Linfocitos T/metabolismo , Adaptación Biológica/genética , Adaptación Biológica/inmunología , Animales , Antígenos/inmunología , Reprogramación Celular/genética , Metabolismo Energético/genética , Regulación de la Expresión Génica , Interacciones Huésped-Patógeno/genética , Interacciones Huésped-Patógeno/inmunología , Humanos , Memoria Inmunológica , Activación de Linfocitos/genética , Neoplasias/inmunología , Neoplasias/metabolismo , Transducción de Señal , Subgrupos de Linfocitos T/citología , Virosis/inmunología , Virosis/metabolismo
18.
JBJS Essent Surg Tech ; 6(3): e31, 2016 Sep 28.
Artículo en Inglés | MEDLINE | ID: mdl-30233924

RESUMEN

The volar locking plate is a popular implant for surgical management of unstable distal radial fractures. We routinely utilize this system for all distal radial fractures except for those with entrapped intra-articular fragments and fractures with a displaced dorsomedial facet fracture (which is hard to capture with the volar approach alone). In this video, we describe in detail the necessary steps for successful placement of the volar locking plate, starting with preoperative planning and ending with expected outcomes. The approach that we utilize is through the flexor carpi radialis tendon sheath and avoids the radial artery. In the video, we describe 4 variations on the application of a volar locking plate: (1) the standard technique after appropriate reduction and provisional fixation with Kirschner wires, (2) regaining length through a shortened distal radial fracture, (3) using the volar plate to assist in the reduction and regain volar tilt, and (4) intraoperative management of coronal shift of the distal fragment. Complications reported for the volar locking plate have decreased with newer low-profile plate designs; however, they still include volar tendon irritation and/or rupture and median neuropathy. Postoperatively, we advise a brief 2-week period of immobilization for wound-healing, which is followed by a period during which a removable wrist splint is used and patients are instructed on the performance of a hand therapy regimen.

19.
PLoS One ; 10(12): e0145237, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26670809

RESUMEN

We previously identified heme oxygenase 1 (HO-1) as a specific target of miR-155, and inhibition of HO-1 activity restored the capacity of miR-155-/- CD4+ T cells to promote antigen-driven inflammation after adoptive transfer in antigen-expressing recipients. Protoporphyrins are molecules recognized for their modulatory effect on HO-1 expression and function. In the present study, we investigated the effect of protoporphyrin treatment on the development of autoimmunity in miR-155-deficient mice. MiR-155-mediated control of HO-1 expression in promoting T cell-driven chronic autoimmunity was confirmed since HO-1 inhibition restored susceptibility to experimental autoimmune encephalomyelitis (EAE) in miR-155-deficient mice. The increased severity of the disease was accompanied by an enhanced T cell infiltration into the brain. Taken together, these results underline the importance of miR-155-mediated control of HO-1 expression in regulating the function of chronically-stimulated T cells in EAE.


Asunto(s)
Encefalomielitis Autoinmune Experimental/tratamiento farmacológico , Encefalomielitis Autoinmune Experimental/genética , MicroARNs/metabolismo , Protoporfirinas/uso terapéutico , Animales , Encéfalo/efectos de los fármacos , Encéfalo/patología , Susceptibilidad a Enfermedades , Encefalomielitis Autoinmune Experimental/patología , Hemo-Oxigenasa 1/antagonistas & inhibidores , Hemo-Oxigenasa 1/metabolismo , Ganglios Linfáticos/efectos de los fármacos , Ganglios Linfáticos/inmunología , Ratones Endogámicos C57BL , MicroARNs/genética , Protoporfirinas/farmacología , Bazo/efectos de los fármacos , Bazo/inmunología , Células TH1/efectos de los fármacos , Células Th17/efectos de los fármacos
20.
Artículo en Inglés | MEDLINE | ID: mdl-26382391

RESUMEN

We study inclined channel flows of sand over a sensor-enabled composite geotextile fabric base that dissipates granular fluctuation energy. We record strain of the fabric along the flow direction with imbedded fiber-optic Bragg gratings, flow velocity on the surface by correlating grain position in successive images, flow thickness with the streamwise shift of an oblique laser light sheet, velocity depth profile through a transparent side wall using a high-speed camera, and overall discharge rate. These independent measurements at inclinations between 33∘ and 37∘ above the angle of repose at 32.1±0.8∘ are consistent with a mass flow rate scaling as the 3/2 power of the flow depth, which is markedly different than flows on a rigid bumpy boundary. However, this power changes to 5/2 when flows are forced on the sand bed below its angle of repose. Strain measurements imply that the mean solid volume fraction in the flowing layer above the angle of repose is 0.268±0.033, independent of discharge rate or inclination.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA