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1.
Talanta ; 206: 120237, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31514830

RESUMO

A new calibration approach based on the adaptation of Integrated Calibration Method (ICM) to consecutive two components analysis in separation science is presented. Consecutive ICM method (C-ICM) was conceptually developed and applied to determination of two excitatory amino acids - glutamate and aspartate in cerebrospinal fluids collected by the use of brain microdialysis from freely-moving animals. Both analytes as a neurotransmitters play an important role in formation of the memory trace, and thus the processes of learning and memory. Due to their low concentration and presence of interferences, considered analytical system - animal brain - was a big challenge. High-performance liquid chromatography (HPLC) with electrochemical detection (ECD) was used in all experimental work. The most important feature of proposed method is integration of interpolative and extrapolative ways to calculate analyte concentration in single calibration procedure, which consequently leads to obtain series of six estimations of analytical result. Comparison of individual estimations with each other allows for a more in-depth analysis of systematic errors. It was proved that C-ICM approach enables diagnosis and compensation of systematic errors induced by occurrence of interference effects and improvement of accuracy of analytical results. Most of all, it was demonstrated that application of this method is efficient and useful analytical tool in analysis of complicated biological samples in pharmacology and neuroscience.


Assuntos
Ácido Aspártico/líquido cefalorraquidiano , Ácido Glutâmico/líquido cefalorraquidiano , Animais , Calibragem , Cromatografia Líquida de Alta Pressão/métodos , Técnicas Eletroquímicas/métodos , Masculino , Camundongos Endogâmicos C57BL , Microdiálise , Neurotransmissores/líquido cefalorraquidiano , Ratos Wistar
2.
J Surg Res ; 245: 537-543, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31470334

RESUMO

BACKGROUND: After an esophageal resection, continuity is commonly restored by a gastric tube reconstruction and an intrathoracic anastomosis to the remaining proximal esophagus. Ischemia of the anastomotic region is considered to play a pivotal role in anastomotic leakage. Microdialysis (µD) is an excellent method to measure local biochemical substances and parameters in a specific organ or compartment aiming at early detection of ischemia. This animal study evaluates ischemia of the gastric tube reconstruction using a novel method-µD on organ surfaces. This promising method may have the potential to detect an anastomotic leakage before clinical symptoms develop. METHODS: Anesthetized normoventilated pigs were used. Surface microdialysis (S-µD) catheters and an intraparenchymal oxygen tension catheter were placed on the stomach. A gastric tube was made and the gastroepiploic artery was divided halfway along the greater curvature to produce severe ischemia at the top of the gastric tube. µD data from four locations (gastric tube, ileum and peritoneal cavity) were recorded every 20 min during the experiment. Tissue samples from all catheter sites underwent histopathological analysis. Intraparenchymal oxygen partial pressure, systemic blood tests, and hemodynamic parameters were recorded. RESULTS: S-µD data showed values indicating severe ischemia at the top of the gastric tube and intermediate ischemia at the level of transection of the gastroepiploic artery. Ischemia was verified by histopathological analysis of tissue samples and intraparenchymal oxygen tension data. CONCLUSIONS: S-µD can detect and grade severity of local ischemia in real time, in an animal model.


Assuntos
Fístula Anastomótica/diagnóstico , Esofagectomia/efeitos adversos , Esôfago/irrigação sanguínea , Isquemia/diagnóstico , Microdiálise/métodos , Anastomose Cirúrgica/efeitos adversos , Animais , Modelos Animais de Doenças , Esôfago/patologia , Esôfago/cirurgia , Humanos , Isquemia/etiologia , Isquemia/patologia , Oxigênio/análise , Índice de Gravidade de Doença , Sus scrofa
3.
J Pharm Biomed Anal ; 177: 112885, 2020 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-31563759

RESUMO

Tianma pills, a traditional formula made from Ligusticum chuanxiong and Gastrodia elata, are efficacious for the treatment of primary headache. Tetramethylpyrazine (TMP) and Ferulic acid (FA) are the bioactive ingredients of Ligusticum chuanxiong, while Gastrodin and Gastrodigenin are the bioactive ingredients of Gastrodia elata. Pharmacokinetic assessment of TMP, FA, gastrodin or gastrodigenin in blood or brain interstitial fluid (BIF) has been reported in healthy animals. However, the pharmacokinetic properties of TMP and FA have not been studied when they are co-administered in a blood-stasis migraine model. The present research investigated the pharmacokinetic behavior of TMP and FA after oral administration in the presence of different concentrations of gastrodin and gastrodigenin in a blood-stasis migraine model. Pharmacokinetic parameters were determined using blood-brain microdialysis in combination with the UHPLC-MS method. Compared to the control group, in which TMP and FA were administrated without gastrodin or gastrodigenin, the T1/2, MRT, Cmax and AUC0-∞ of TMP and FA were increased. These results indicate that varying concentrations of gastrodin and gastrodigenin play an important role in affecting the pharmacokinetics of TMP and FA. Low concentrations of gastrodin and gastrodigenin (similar to those found in Tianma pills) were more efficacious, validating the utility of the ancient formulation.


Assuntos
Barreira Hematoencefálica/metabolismo , Medicamentos de Ervas Chinesas/farmacocinética , Gastrodia/química , Ligusticum/química , Transtornos de Enxaqueca/tratamento farmacológico , Administração Oral , Animais , Álcoois Benzílicos/administração & dosagem , Álcoois Benzílicos/farmacocinética , Barreira Hematoencefálica/química , Barreira Hematoencefálica/citologia , Temperatura Baixa/efeitos adversos , Ácidos Cumáricos/administração & dosagem , Ácidos Cumáricos/farmacocinética , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Interações de Medicamentos , Medicamentos de Ervas Chinesas/administração & dosagem , Medicamentos de Ervas Chinesas/química , Líquido Extracelular/química , Glucosídeos/administração & dosagem , Glucosídeos/farmacocinética , Humanos , Masculino , Microdiálise , Transtornos de Enxaqueca/sangue , Transtornos de Enxaqueca/etiologia , Permeabilidade , Pirazinas/administração & dosagem , Pirazinas/farmacocinética , Ratos , Organismos Livres de Patógenos Específicos , Vasoconstrição/efeitos dos fármacos
4.
Medicine (Baltimore) ; 98(45): e17843, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31702640

RESUMO

BACKGROUND: Acupuncture therapy is frequently used to treat Knee Osteoarthritis (KOA) in clinic, and usually used local acupoints near the diseased knees as therapeutic targets. Some local acupoints appeared sensitization phenomenon which was called sensitized acupoints, which were regarded as important therapeutic targets to get better therapeutic effect on clinic. Therefore, it is necessary to explore the biological basis of acupoint sensitization. Meanwhile, there is a lack of an analysis of the metabolism for sensitized acupoints in KOA patients. Considering that acupuncture effect could be multi-targeted, omics (such as metabolomics) may be a useful method to reveal the relationship between sensitized acupoints and clinical efficacy of acupuncture. METHODS AND ANALYSIS: This study is a parallel design trial. Thirty KOA patients and 30 healthy volunteers will be recruited in this study. Mechanical pain threshold will be measured by Electron Von frey in order to confirm the highest sensitized acupoints. Then collect tissue fluid from the highest sensitized acupoints by micro dialysis technical, then apply electro-acupuncture method on the highest sensitized acupoints to treat KOA patients, after 20 sessions treatments, measure and collect again. Liquid chromatography-tandem mass spectrometry method will be used to analyze the metabonomics of dialysate. RESULTS: This study will provide a high-quality evidence to reveal the local molecular mechanism of acupuncture sensitized acupoints for patient with KOA. CONCLUSION: This study will provide up-date evidence of whether acupuncture sensitized acupoints have local molecular mechanism for KOA. TRIAL REGISTRATION NUMBER: NCT03599180 (24 Jul. 2018).


Assuntos
Terapia por Acupuntura/métodos , Exsudatos e Transudatos/química , Metabolômica/métodos , Osteoartrite do Joelho/terapia , Pontos de Acupuntura , Idoso , Estudos de Casos e Controles , Feminino , Humanos , Masculino , Microdiálise , Pessoa de Meia-Idade , Osteoartrite do Joelho/metabolismo , Projetos Piloto
5.
APMIS ; 127(12): 779-788, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31515843

RESUMO

Cefuroxime is widely used as antibiotic prophylaxis for orthopaedic procedures. We evaluated bone, subcutaneous tissue (SCT) and plasma pharmacokinetics of cefuroxime in male patients undergoing total knee replacement (TKR) after both traditional short-term infusion (STI) and continuous infusion (CI). Eighteen male patients undergoing TKR were randomly assigned to STI or CI of 1.5 g of cefuroxime. Measurements were obtained in plasma, SCT, cancellous and cortical bone every 30 min for 8 h following surgery. For sampling in solid tissues, microdialysis was applied. Population pharmacokinetic modelling was performed in order to estimate pharmacokinetic parameters, and to assess the probability of attaining cefuroxime concentrations above clinically relevant minimal inhibitory concentrations (MICs) for 65% and 90% of the 8 h dosing interval. Low SCT and cortical bone penetration were found in both the STI and the CI group, but the findings were only significant in the STI group. Irrespective of MIC, tissue and target, CI leads to improved probability of attaining relevant pharmacokinetic targets compared with STI. For the Staphylococcus aureus MIC breakpoint (4 µg/mL), STI leads to inadequate probability of target attainment. CI of 1.5 g of cefuroxime leads to improved probability of attaining relevant pharmacokinetic targets in male TKR patients compared with traditional STI. These findings suggest that application of CI may improve antibiotic prophylaxis for male TKR patients.


Assuntos
Antibacterianos/administração & dosagem , Antibacterianos/farmacocinética , Antibioticoprofilaxia/métodos , Artroplastia do Joelho , Cefuroxima/administração & dosagem , Cefuroxima/farmacocinética , Infecções Relacionadas à Prótese/prevenção & controle , Idoso , Antibacterianos/sangue , Osso e Ossos/metabolismo , Cefuroxima/sangue , Esquema de Medicação , Humanos , Infusões Intravenosas , Masculino , Testes de Sensibilidade Microbiana , Microdiálise , Pessoa de Meia-Idade , Tela Subcutânea/metabolismo
6.
Artigo em Inglês | MEDLINE | ID: mdl-31302476

RESUMO

In this study, a simple, efficient and rapid Ultra High Performance Liquid Chromatography method with fluorescence detection (UHPLC-FLD) has been developed and validated for the determination of Ochratoxin-A (OTA) in rat brain microdialysates and plasma samples. Six adult male wistar rats were used in the study and a single dose (5 mg/kg b.w.) of OTA was given by intraperitoneal (i.p.) injection. Rat blood and microdialysate samples were collected simultaneously after i.p. injection in awake freely moving rats, over a twelve-hour period. An UHPLC analysis was performed on a Zorbax Eclipse Plus C8 (150 mm × 3.0 mm ID × 1.8 µm particles) column with a mobile phase of acetonitrile:water:phosphoric acid (50:50:0.1, v/v) using a flow rate of 0.6 mL/min. The fluorescence detector was set at 330 nm excitation and 460 nm emission wavelengths. Diflunisal (DIF) was used as an internal standard (IS). OTA and IS were separated within 5 min under these conditions. The method was validated in terms of linearity, precision, accuracy, limit of detection, limit of quantification, and stability. Calibration curves obtained with spiked biological matrices show good linearity with high correlation coefficients. The intra- and inter-day assay variability was <5% for the OTA. The limit of detection and the limit of quantification values were found to be 0.490 ng/mL and 1.48 ng/mL for plasma; 0.0900 ng/mL and 0.270 ng/mL for microdialysate samples, respectively. This method was successfully applied for the monitoring of OTA levels in the rat brain and plasma samples.


Assuntos
Química Encefálica , Cromatografia Líquida de Alta Pressão/métodos , Ocratoxinas/análise , Animais , Cromatografia Líquida de Alta Pressão/instrumentação , Limite de Detecção , Masculino , Microdiálise , Ocratoxinas/sangue , Ocratoxinas/farmacocinética , Plasma/química , Ratos , Vigília
7.
J Craniomaxillofac Surg ; 47(8): 1306-1309, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31337567

RESUMO

BACKGROUND: Reconstruction with free flaps has become a usual practice in maxillofacial surgery. Clinical monitoring is still the standard approach for postoperative follow-up, but can be difficult or impossible with intraorally situated or buried flaps. Microdialysis is a sampling technique that offers the possibility to monitor the metabolism of flaps continuously. It is a reliable method for early diagnosis of ischemia. MATERIALS AND METHODS: 48 microvascular free flaps applied following oral cancer resection were monitored with a microdialysis (MD) catheter, placed in the flap. Glucose, lactate, and lactate/pyruvate ratio were monitored using a bedside analyser for 5 days. 48 free flaps served as controls and were assessed (refill, flap temperature, and color) by clinical monitoring (CM). RESULTS: 12 flaps monitored by MD showed abnormal metabolism and underwent revision. Eight flaps were saved and four were lost within the first 5 days postoperatively. In addition, two flaps were lost at days 15 and 30 postoperatively, without previous complications. Four flaps assessed by CM developed complications, underwent revision, and were saved. In addition, five flaps were lost between the 8th and 23rd days postoperatively, without revision, due to missing previous clinical signs. CONCLUSION: Postoperative monitoring of free flaps using a microdialysis decision algorithm allows early diagnosis of anastomotic complications. It is a clinically feasible and sensitive monitoring method for microvascular flaps, allowing surgical revision to be undertaken before clinical alteration takes place.


Assuntos
Retalhos de Tecido Biológico , Procedimentos Cirúrgicos Reconstrutivos , Algoritmos , Humanos , Isquemia , Microdiálise , Monitorização Fisiológica , Complicações Pós-Operatórias
8.
Anal Bioanal Chem ; 411(23): 5929-5935, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31338538

RESUMO

Because cerebral species involve rapid events, increasing the temporal resolution to realize in vivo near-real-time measurements is desirable. Here, we aimed to improve the low resolution of our previous on-line electroanalytical system by decreasing the dead volume and reducing molecular dispersion. This updated system has advantages of elevated time resolution and accelerated analysis for on-line monitoring of glucose versus the previous system. Finally, this new system was successfully applied to continuous measurement of cerebral glucose in vivo during global ischemia/reperfusion events. This study is expected to offer a reliable on-line analytical platform for continuous monitoring of important species associated with fast physiological and pathological events in vivo. Graphical abstract.


Assuntos
Encéfalo/metabolismo , Técnicas Eletroquímicas/instrumentação , Glucose/metabolismo , Microdiálise/instrumentação , Animais , Técnicas Biossensoriais/instrumentação , Química Encefálica , Desenho de Equipamento , Glucose/análise , Masculino , Ratos Sprague-Dawley
9.
Nat Commun ; 10(1): 2741, 2019 06 21.
Artigo em Inglês | MEDLINE | ID: mdl-31227695

RESUMO

Knowing how biomarker levels vary within biological fluids over time can produce valuable insight into tissue physiology and pathology, and could inform personalised clinical treatment. We describe here a wearable sensor for monitoring biomolecule levels that combines continuous fluid sampling with in situ analysis using wet-chemical assays (with the specific assay interchangeable depending on the target biomolecule). The microfluidic device employs a droplet flow regime to maximise the temporal response of the device, using a screw-driven push-pull peristaltic micropump to robustly produce nanolitre-sized droplets. The fully integrated sensor is contained within a small (palm-sized) footprint, is fully autonomous, and features high measurement frequency (a measurement every few seconds) meaning deviations from steady-state levels are quickly detected. We demonstrate how the sensor can track perturbed glucose and lactate levels in dermal tissue with results in close agreement with standard off-line analysis and consistent with changes in peripheral blood levels.


Assuntos
Dispositivos Lab-On-A-Chip , Técnicas Analíticas Microfluídicas/instrumentação , Sistemas Automatizados de Assistência Junto ao Leito , Pele/química , Dispositivos Eletrônicos Vestíveis , Biomarcadores/análise , Glicemia/análise , Desenho de Equipamento , Glucose/análise , Voluntários Saudáveis , Humanos , Ácido Láctico/análise , Microdiálise/instrumentação , Microdiálise/métodos , Técnicas Analíticas Microfluídicas/métodos
10.
Trials ; 20(1): 344, 2019 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-31182135

RESUMO

BACKGROUND: Neurological injuries remain the leading cause of death in comatose patients resuscitated from out-of-hospital cardiac arrest (OHCA). Adequate blood pressure is of paramount importance to optimize cerebral perfusion and to minimize secondary brain injury. Markers measuring global cerebral ischemia caused by cardiac arrest and consecutive resuscitation and reflecting the metabolic variations after successful resuscitation are needed to assist a more individualized post-resuscitation care. Currently, no technique is available for bedside evaluation of global cerebral energy state, and until now blood pressure targets have been based on limited clinical evidence. Recent experimental and clinical studies indicate that it might be possible to evaluate cerebral oxidative metabolism from measuring the lactate-to-pyruvate (LP) ratio of the draining venous blood. In this study, jugular bulb microdialysis and immediate bedside biochemical analysis are introduced as new diagnostic tools to evaluate the effect of higher mean arterial blood pressure on global cerebral metabolism and the degree of cellular damage after OHCA. METHODS/DESIGN: This is a single-center, randomized, double-blinded, superiority trial. Sixty unconscious patients with sustained return of spontaneous circulation after OHCA will be randomly assigned in a one-to-one fashion to low (63 mm Hg) or high (77 mm Hg) mean arterial blood pressure target. The primary end-point will be a difference in mean LP ratio within 48 h between blood pressure groups. Secondary end-points are (1) association between LP ratio and all-cause intensive care unit (ICU) mortality and (2) association between LP ratio and survival to hospital discharge with poor neurological function. DISCUSSION: Markers measuring cerebral ischemia caused by cardiac arrest and consecutive resuscitation and reflecting the metabolic changes after successful resuscitation are urgently needed to enable a more personalized post-resuscitation care and prognostication. Jugular bulb microdialysis may provide a reliable global estimate of cerebral metabolic state and can be implemented as an entirely new and less invasive diagnostic tool for ICU patients after OHCA and has implications for early prognosis and treatment. TRIAL REGISTRATION: ClinicalTrials.gov (ClinicalTrials.gov Identifier: NCT03095742 ). Registered March 30, 2017.


Assuntos
Pressão Sanguínea , Encéfalo/metabolismo , Reanimação Cardiopulmonar , Metabolismo Energético , Parada Cardíaca Extra-Hospitalar/terapia , Projetos de Pesquisa , Método Duplo-Cego , Humanos , Ácido Láctico/metabolismo , Microdiálise , Ácido Pirúvico/metabolismo
11.
Mikrochim Acta ; 186(7): 404, 2019 06 10.
Artigo em Inglês | MEDLINE | ID: mdl-31183564

RESUMO

An online flow reactor was fabricated by using a fused deposition modeling three-dimensional printing (3DP) technology along with thermoplastic poly(lactic acid) filaments incorporating copper oxide nanoparticles (CuO NPs). In the presence of glucose, the flow reactor displays multi-catalytic activities because accelerates the oxidation of 2',7'-dichlorodihydrofluorescein to form fluorescein which displays green fluorescence under 480 nm excitation (emission wavelength: 530 nm). The CuO NPs exert two functions to mediate electron transfer at a basic reaction condition, viz. direct oxidation of glucose to generate reactive oxygen species (ROS), and prompting the ROS to oxidize 2',7'-dichlorofluorescin diacetate. The flow reactor coupled to a microdialysis sampler and a fluorometer was applied for online fluorometric monitoring of brain extracellular glucose levels in living rats based on scanning of time-resolved fluorescence intensities. After optimization of (a) the manufacture of the flow reactor, (b) the reaction conditions (pH 10; 50 °C), and (c) the online analytical system, the detection limit of the method (when using 10-µL samples of microdialysate) is as low as 6.1 µM (linear range: 0.05-5 mM) with a sampling frequency of 7.5 h-1. To illustrate the method's applicability, analyses of spiked off-line-collected rat brain microdialysates were conducted. In addition, rat brain extracellular glucose levels were monitored in-vivo and online upon neuronal depolarization triggered by perfusing a high-K+ medium. The results demonstrate that functionalizing raw 3DP materials with appropriate nanomaterials can simplify the manufacturing of analytical devices and related analytical procedures. This will extend the diversity and adaptability of current 3DP-enabling analytical strategies. Graphical abstract Schematic presentation of an online flow reactor fabricated using a fused deposition modeling 3D printer along with poly(lactic acid) (PLA) filaments incorporating CuO NPs. The manufactured flow reactor displays multi-catalytic activities and simplifies online fluorometric monitoring of living rat brain extracellular glucose.


Assuntos
Cobre/química , Fluoresceínas/química , Corantes Fluorescentes/química , Glucose/análise , Nanopartículas Metálicas/química , Impressão Tridimensional , Animais , Técnicas Biossensoriais/instrumentação , Técnicas Biossensoriais/métodos , Encéfalo/metabolismo , Glucose/metabolismo , Limite de Detecção , Masculino , Microdiálise , Monitorização Fisiológica , Oxirredução , Poliésteres/química , Ratos , Ratos Sprague-Dawley , Espécies Reativas de Oxigênio/metabolismo , Espectrometria de Fluorescência/instrumentação
12.
Biomed Chromatogr ; 33(10): e4626, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31222753

RESUMO

N-Ethylpentylone (NEP) is a popular synthetic cathinone abused worldwide. To obtain more information about its pharmacokinetics and pharmacodynamics, a rapid, simple and sensitive liquid chromatography-tandem mass spectrometry method was developed for the determination of NEP, two important neurotransmitters, dopamine and serotonin, and their metabolites, including 3,4-dihydroxyphenylacetic acid, 3-methoxytyramine and 5-hydroxyindole-3-acetic acid, in rat brain microdialysate. The analytes were separated on a Phnomenex Polar C18 column, with a mobile phase of 0.1% formic acid in water (A) and 0.1% formic acid in acetonitrile (B) under gradient elution to shorten the total chromatographic run time. A triple quadruple mass spectrometer coupled with an electrospray ionization source in both positive and negative ion mode was used to detect the analytes. This method showed excellent accuracy (87.4-113.5%) and precision (relative standard deviation <15%) at three quality control levels. The limits of detection were 0.2 ng/mL for NEP and 0.2-50 nm for the others and good linearity was obtained. This study pioneered a method to integrate exogenous drugs and endogenous neurotransmitters as the drugs act on the same determination system, which means that this innovation can provide support for further study of the addictive effects of NEP or other synthetic cathinones on extracellular levels of dopamine and 5-hydroxytryptamine.


Assuntos
Benzodioxóis/análise , Butilaminas/análise , Cromatografia Líquida de Alta Pressão/métodos , Dopamina/análise , Núcleo Accumbens/química , Serotonina/análise , Animais , Benzodioxóis/administração & dosagem , Benzodioxóis/farmacocinética , Butilaminas/administração & dosagem , Butilaminas/farmacocinética , Dopamina/metabolismo , Limite de Detecção , Modelos Lineares , Microdiálise , Núcleo Accumbens/metabolismo , Ratos , Reprodutibilidade dos Testes , Serotonina/metabolismo , Espectrometria de Massas em Tandem/métodos
13.
PLoS One ; 14(6): e0217573, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31170198

RESUMO

Pharmacological efficacy is based on the drug concentration in target tissues, which usually cannot be represented by the plasma concentration. The purpose of this study was to compare the pharmacokinetic characteristics of gemifloxacin in plasma and skeletal muscle and evaluate its tissue penetration in both healthy and MRSA (methicillin-resistant Staphylococcus aureus)-infected rats. A microdialysis (MD) combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated to determine free gemifloxacin concentrations in rat plasma and skeletal muscle simultaneously. The in vivo recoveries of MD were 23.21% ± 3.42% for skeletal muscle and 20.62% ± 3.19% for plasma, and were concentration independent. We provided evidence that the method developed here meets FDA requirements. Additionally, this method was successfully applied to the determination of free gemifloxacin in rats. Muscle and blood dialysates were collected after an 18 mg/kg intravenous bolus dose. The mean areas under the concentration-time curves (AUCs) from 0 to 9 h for skeletal muscle and plasma were 3641.50 ± 915.65 h*ng/mL and 7068.32 ± 1964.19 h*ng/mL in MRSA-infected rats and 3774.72 ± 700.36 h*ng/mL and 6927.49 ± 1714.86 h*ng/mL in healthy rats, respectively. There was no significant difference (P>0.05) in gemifloxacin exposure between healthy rats and MRSA-infected rats for plasma or muscle. The low ratio of AUC0-9 muscle to AUC0-9 plasma suggested lower drug exposure in skeletal muscle than in plasma for both healthy and MRSA-infected rats. Our study suggested that the administration of gemifloxacin according to drug levels in plasma to treat local infection is unreasonable and might result in an inadequate dose regimen.


Assuntos
Gemifloxacina/análise , Gemifloxacina/farmacologia , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Microdiálise , Músculos/efeitos dos fármacos , Músculos/microbiologia , Espectrometria de Massas em Tandem , Animais , Proteínas Sanguíneas/metabolismo , Cromatografia Líquida , Ciprofloxacino/química , Ciprofloxacino/farmacologia , Modelos Animais de Doenças , Gemifloxacina/química , Gemifloxacina/farmacocinética , Masculino , Ligação Proteica , Ratos Sprague-Dawley , Reprodutibilidade dos Testes , Coxa da Perna/microbiologia , Distribuição Tecidual
14.
Stroke ; 50(7): 1887-1890, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31182001

RESUMO

Background and Purpose- Hypoxic-ischemic brain damage is a well-recognized physiopathologic mechanism after aneurysmal subarachnoid hemorrhage (aSAH). The Ngb (neuroglobin) is a hemoprotein predominantly expressed in the brain with a high affinity for oxygen. Relationship between serum Ngb level and brain metabolism in aSAH patients has not been investigated previously. Methods- Thirty-six consecutive severe aSAH patients (Glasgow Coma Scale score ≤8 on admission) with multimodal neuromonitoring and 36 matched healthy subjects were included. Serum Ngb level was analyzed in combination with other time-matched cerebral microdialysis parameters, brain tissue oxygen tension, and 12-month neurological outcomes. Results- Serum Ngb level was correlated positively with cerebral microdialysis parameters and brain tissue oxygen tension ( P<0.001). Poor functional outcome (modified Rankin Scale score >3) 12 months after aSAH was associated with higher Ngb level but independent of age, sex, and disease severity ( P<0.001). A similar association was found between high Ngb level and neuropsychological test results indicative of impairments in cognition, visual conceptualization, and frontal executive functions ( P<0.001). Conclusions- Ngb may be a potential biomarker for reflecting brain tissue oxygen tension, brain metabolism, and functional outcome in severe aSAH patients and merits further study in the context of aSAH.


Assuntos
Química Encefálica , Neuroglobina/sangue , Hemorragia Subaracnóidea/metabolismo , Idoso , Biomarcadores/sangue , Feminino , Escala de Coma de Glasgow , Humanos , Masculino , Microdiálise , Pessoa de Meia-Idade , Doenças do Sistema Nervoso/etiologia , Testes Neuropsicológicos , Consumo de Oxigênio , Recuperação de Função Fisiológica , Hemorragia Subaracnóidea/psicologia , Hemorragia Subaracnóidea/terapia , Resultado do Tratamento
15.
EBioMedicine ; 44: 607-617, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31202815

RESUMO

BACKGROUND: Traumatic brain injury (TBI) is recognized as a metabolic disease, characterized by acute cerebral glucose hypo-metabolism. Adaptive metabolic responses to TBI involve the utilization of alternative energy substrates, such as ketone bodies. Cerebral microdialysis (CMD) has evolved as an accurate technique allowing continuous sampling of brain extracellular fluid and assessment of regional cerebral metabolism. We present the successful application of a combined hypothesis- and data-driven metabolomics approach using repeated CMD sampling obtained routinely at patient bedside. Investigating two patient cohorts (n = 26 and n = 12), we identified clinically relevant metabolic patterns at the acute post-TBI critical care phase. METHODS: Clinical and CMD metabolomics data were integrated and analysed using in silico and data modelling approaches. We used both unsupervised and supervised multivariate analysis techniques to investigate structures within the time series and associations with patient outcome. FINDINGS: The multivariate metabolite time series exhibited two characteristic brain metabolic states that were attributed to changes in key metabolites: valine, 4-methyl-2-oxovaleric acid (4-MOV), isobeta-hydroxybutyrate (iso-bHB), tyrosyine, and 2-ketoisovaleric acid (2-KIV). These identified cerebral metabolic states differed significantly with respect to standard clinical values. We validated our findings in a second cohort using a classification model trained on the cerebral metabolic states. We demonstrated that short-term (therapeutic intensity level (TIL)) and mid-term patient outcome (6-month Glasgow Outcome Score (GOS)) can be predicted from the time series characteristics. INTERPRETATION: We identified two specific cerebral metabolic patterns that are closely linked to ketometabolism and were associated with both TIL and GOS. Our findings support the view that advanced metabolomics approaches combined with CMD may be applied in real-time to predict short-term treatment intensity and long-term patient outcome.


Assuntos
Lesões Encefálicas Traumáticas/metabolismo , Encéfalo/metabolismo , Corpos Cetônicos/metabolismo , Adulto , Biomarcadores , Lesões Encefálicas Traumáticas/líquido cefalorraquidiano , Lesões Encefálicas Traumáticas/diagnóstico , Lesões Encefálicas Traumáticas/terapia , Cromatografia Líquida , Biologia Computacional/métodos , Feminino , Escala de Coma de Glasgow , Humanos , Pressão Intracraniana , Masculino , Metaboloma , Metabolômica/métodos , Microdiálise , Pessoa de Meia-Idade , Avaliação de Resultados da Assistência ao Paciente , Prognóstico , Curva ROC , Estudos Retrospectivos , Espectrometria de Massas em Tandem
16.
Neurocrit Care ; 30(Suppl 1): 46-59, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31144274

RESUMO

INTRODUCTION: Development of clinical biomarkers to guide therapy is an important unmet need in aneurysmal subarachnoid hemorrhage (SAH). A wide spectrum of plausible biomarkers has been reported for SAH, but none have been validated due to significant variabilities in study design, methodology, laboratory techniques, and outcome endpoints. METHODS: A systematic review of SAH biomarkers was performed per the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The panel's recommendations focused on harmonization of (1) target cellular and molecular biomarkers for future investigation in SAH, (2) standardization of best-practice procedures in biospecimen and biomarker studies, and (3) experimental method reporting requirements to facilitate meta-analyses and future validation of putative biomarkers. RESULTS: No cellular or molecular biomarker has been validated for inclusion as "core" recommendation. Fifty-four studies met inclusion criteria and generated 33 supplemental and emerging biomarker targets. Core recommendations include best-practice protocols for biospecimen collection and handling as well as standardized reporting guidelines to capture the heterogeneity and variabilities in experimental methodologies and biomarker analyses platforms. CONCLUSION: Significant variabilities in study design, methodology, laboratory techniques, and outcome endpoints exist in SAH biomarker studies and present significant barriers toward validation and translation of putative biomarkers to clinical use. Adaptation of common data elements, recommended biospecimen protocols, and reporting guidelines will reduce heterogeneity and facilitate future meta-analyses and development of validated clinical biomarkers in SAH.


Assuntos
Aneurisma Roto/metabolismo , Biomarcadores/metabolismo , Elementos de Dados Comuns , Aneurisma Intracraniano/metabolismo , Hemorragia Subaracnóidea/metabolismo , Aneurisma Roto/complicações , Pesquisa Biomédica , Isquemia Encefálica/etiologia , Isquemia Encefálica/metabolismo , Humanos , Microdiálise , Mortalidade , National Institute of Neurological Disorders and Stroke (USA) , National Library of Medicine (U.S.) , Prognóstico , Manejo de Espécimes , Hemorragia Subaracnóidea/complicações , Estados Unidos , Vasoespasmo Intracraniano/etiologia , Vasoespasmo Intracraniano/metabolismo
17.
J Pharm Biomed Anal ; 173: 126-133, 2019 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-31129532

RESUMO

A bioanalytical LC-MS/MS method was developed and validated for the simultaneous quantification of capsaicin (CAPS) and dihydrocapsaicin (D-CAPS) in dermal microdialysis samples from rats. Capsaicinoids were separated by using a C18 column, with a mobile phase of water and acetonitrile, both with 0.1% of formic acid, eluted as a gradient. Compounds were detected by using an electrospray ionization source operating in the positive mode (ESI+) to monitor the m/z transitions of 306.1 > 137.0 for CAPS and 308.1 > 137.0 for D-CAPS. The method showed linearity in the concentration range of 0.5-100 ng/ml for CAPS and 0.25-100 ng/ml for D-CAPS, with coefficients of determination of ≥ 0.99. The inter- and intra-day precision, accuracy, and compound stability in different conditions were in accordance with the limits established by the US Food and Drug Administration guidelines. The recovery of the drugs by microdialysis were dependent on the flow rate, but independent of drug concentration. For CAPS, calibration of the in vitro microdialysis probes by dialysis and retrodialysis resulted in statistically similar drug recovery of 68.5% ± 5.9% and 77.8% ± 6.6%, respectively, at a flow rate of 0.5 µl/min. For D-CAPS, the recovery by dialysis was lower than by retrodialysis, at 51.4% ± 6.6% and 92.6% ± 2.4%, respectively. This difference was attributed to the binding of D-CAPS to the plastic tubing, which was experimentally evaluated and mathematically modeled. In vivo recoveries were 75.7% ± 6.3% for CAPS and 81.9% ± 1.5% for D-CAPS at the same flow rate. The analytical method showed high specificity, accuracy, and sensitivity, and suitability for dermatopharmacokinetic studies. These results will allow the determination of the actual free concentration of these drugs in dermatopharmacokinetic experiments, as shown in a pilot experiment with a commercial cream containing capsaicinoids.


Assuntos
Capsaicina/análogos & derivados , Capsaicina/análise , Fármacos do Sistema Sensorial/análise , Creme para a Pele/análise , Animais , Capsaicina/administração & dosagem , Capsaicina/farmacocinética , Cromatografia Líquida de Alta Pressão/métodos , Derme/química , Masculino , Microdiálise/métodos , Modelos Animais , Ratos , Ratos Wistar , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Fármacos do Sistema Sensorial/administração & dosagem , Fármacos do Sistema Sensorial/farmacocinética , Creme para a Pele/administração & dosagem , Creme para a Pele/farmacocinética , Espectrometria de Massas em Tandem/métodos , Distribuição Tecidual
18.
Lab Chip ; 19(11): 2038-2048, 2019 06 07.
Artigo em Inglês | MEDLINE | ID: mdl-31094398

RESUMO

This paper presents the design, optimisation and fabrication of a mechanically robust 3D printed microfluidic device for the high time resolution online analysis of biomarkers in a microdialysate stream at microlitre per minute flow rates. The device consists of a microfluidic channel with secure low volume connections that easily integrates electrochemical biosensors for biomarkers such as glutamate, glucose and lactate. The optimisation process of the microfluidic channel fabrication, including for different types of 3D printer, is explained and the resulting improvement in sensor response time is quantified. The time resolution of the device is characterised by recording short lactate concentration pulses. The device is employed to record simultaneous glutamate, glucose and lactate concentration changes simulating the physiological response to spreading depolarisation events in cerebrospinal fluid dialysate. As a proof-of-concept study, the device is then used in the intensive care unit for online monitoring of a brain injury patient, demonstrating its capabilities for clinical monitoring.


Assuntos
Encéfalo/metabolismo , Dispositivos Lab-On-A-Chip , Microdiálise/instrumentação , Neuroquímica/instrumentação , Impressão Tridimensional , Técnicas Biossensoriais , Encéfalo/citologia , Desenho de Equipamento , Humanos , Sistemas On-Line , Razão Sinal-Ruído
19.
Chemosphere ; 229: 41-50, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31071518

RESUMO

Element cycling in the terrestrial environment is heavily reliant upon processes that occur in soil solution. Here we present the first application of microdialysis to sample iodine from soil solution. In comparison to conventional soil solution extraction methods such as Rhizon™ samplers, centrifugation, and high-pressure squeezing, microdialysis can passively sample dissolved compounds from soil solution without altering the in-situ speciation of trace elements at realistic soil moisture conditions. In order to assess the suitability of microdialysis for sampling iodine, the permeability factors and effect of perfusion flowrate on I- and IO3- recovery was examined in stirred solutions. Furthermore, microdialysis was used to sample native soluble iodine at a range of water contents and iodine-enriched soils to investigate iodine soil dynamics. Total iodine concentrations were measured using ICP-MS. Inorganic species and the molecular weight distribution of organically bound iodine were determined by anion exchange and size exclusion chromatography (SEC) coupled to an ICP-MS, respectively. The most effective recovery rates in stirred solution were observed with the slowest perfusion flowrate yielding 66.2 ±â€¯7.1 and 70.5 ±â€¯7.1% for I- and IO3-, respectively. Microdialysis was proven to be capable of sampling dissolved iodine from the soil solution, which accounted for <2.5% of the total soil iodine and speciation followed the sequence: organic-I > I- > IO3-. The use of SEC coupled to (i) UV and (ii) ICP-MS analysis provided detail regarding the molecular weight distribution of dissolved org-I compounds. Dissolved org-I was detected with approximate molecular weights between 0.1 and 4.5 kDa. The results in this study show that microdialysis is a suitable technique for sampling dissolved iodine species from soils maintained at realistic moisture contents. In addition, inorganic iodine added to soils was predominately bound with relatively low molecular weight (<4.5 kDa) soluble organic matter.


Assuntos
Iodo/química , Espectrometria de Massas/métodos , Microdiálise/métodos , Solo/química
20.
Int J Nanomedicine ; 14: 2327-2340, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31015760

RESUMO

Background: 8-methoxypsoralen (8-MOP) is one of the most commonly utilized drugs in psoralen-ultraviolet A therapy for treatment of vitiligo. However, poor skin retention and systemic side effects limit the clinical application of 8-MOP. Methods: Microemulsions (MEs) and chitosan derivative-coated 8-MOP MEs were developed and compared for dermal delivery of 8-MOP. Ex vivo skin retention/permeation study was performed to select the ME formulation with the highest retention:permeation ratio. Four different chitosan-coated MEs were prepared and compared with the ME formulation for their ability to distribute 8-MOP in the skin. Results: Among various ME formulations developed, a formulation containing 2.9% ethyl oleate, 17.2% Cromophor EL35, 8.6% ethanol and 71.3% water showed the highest ex vivo skin retention:permeation ratio (1.98). Of four chitosan-coated MEs prepared, carboxymethyl chitosan-coated MEs (CC-MEs) and hydroxypropyl chitosan-coated MEs (HC-MEs) showed higher ex vivo skin retention:permeation ratio (1.46 and 1.84). and were selected for in vivo pharmacokinetic study. AUCskin (0-12 h) for 8-MOP MEs (4578.56 h·ng·mL-1) was higher than HC-MEs (3422.47 h·ng·mL-1), CC-MEs (2808.51 h·ng·mL-1) and tincture (1500.16 h·ng·mL-1). Also, AUCplasma (0-12 h) for MEs (39.35±13.90 h·ng·mL-1) was significantly lower than HC-MEs (66.32 h·ng·mL-1), CC-MEs (59.70 h·ng·mL-1) and tincture (73.02 h·ng·mL-1). Conclusion: These combined results suggested that the MEs developed could be a promising and safe alternative for targeted skin delivery of 8-MOP.


Assuntos
Quitosana/química , Sistemas de Liberação de Medicamentos , Emulsões/química , Metoxaleno/administração & dosagem , Administração Cutânea , Animais , Quitosana/análogos & derivados , Humanos , Masculino , Microdiálise , Permeabilidade , Ratos Sprague-Dawley , Pele/metabolismo , Absorção Cutânea , Suínos
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