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1.
Mass Spectrom Rev ; 2020 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-32412674

RESUMO

Among the different techniques for mass analysis, ultra-high-resolution Fourier transform ion cyclotron resonance (FTICR) is the method of choice for highly complex samples, as it offers unrivaled mass accuracy and resolving power, combined with a high degree of flexibility in hybrid instruments as well as for ion activation techniques. FTICR instruments are readily embraced by the biological and biomedical research communities and applied over a wide range of applications for the analysis of biomolecules such as carbohydrates, lipids, nucleic acids, and proteins. In the field of natural organic matter (NOM) analysis, petroleum-related studies currently dominate FTICR-MS applications. Recently, however, there is a growing interest in developing high-performance MS methods for the characterization of NOM samples from natural aquatic and terrestrial environments. Here, we present an overview of FTICR-MS techniques for complex, non-petroleum NOM samples, including data analysis and novel tandem mass spectrometry (MS/MS) methods for structural classifications. © 2020 The Authors. Mass Spectrometry Reviews published by John Wiley & Sons Ltd.

2.
Artigo em Inglês | MEDLINE | ID: mdl-32311473

RESUMO

OBJECTIVES: The aim was to characterize linezolid population pharmacokinetics in plasma and interstitial space fluid of subcutaneous adipose tissue (target site) of obese compared with non-obese patients and to determine dosing regimens enabling adequate therapy using Monte Carlo simulations. METHODS: In this prospective, parallel group, open-label, controlled, single-centre trial, 30 surgery patients (15 obese, 15 non-obese) received 600 mg of intravenous linezolid. A population pharmacokinetic analysis characterizing plasma and microdialysis-derived target site pharmacokinetics was followed by Monte Carlo simulations using twice/thrice daily 600-1200 mg short-term and extended infusions of linezolid. Adequacy of therapy was assessed by the probability of pharmacokinetic/pharmacodynamic target attainment for time and exposure-related indices. RESULTS: In the model, lean body weight and obesity status largely explained between-patient variability in linezolid PK parameters (12.0-44.9%). Both factors caused lower area under the concentration-time curve in typical obese patients in plasma (-20.4%, 95% CI -22.0% to -15.9%) and at target-site (-37.7%, 95% CI -47.1% to -24.2%) compared with non-obese patients. Probability of target attainment showed improvement with increasing linezolid doses. Depending on lean body weight, adequate therapy was partially attained for 900- and 1200-mg linezolid doses and minimum inhibitory concentrations (MICs) ≤2 mg/L (probability of target attainment 62.5-100%) but could not be reached for MIC = 4 mg/L (probability of target attainment ≤82.3%). Additionally, lower linezolid distribution into the target site in obese patients as described above might compromise the plasma-based probability of target attainment analysis. DISCUSSION: This analysis revealed risks of linezolid underdosing in empirical antibiotic therapy of most resistant bacteria for obese and non-obese patients. Doubling the standard dose is associated with adequate probability of target attainment throughout most body masses for MIC ≤2 mg/L. Further clinical studies with adjusted dosing regimens in for example intensive care patients are needed.

3.
Sci Total Environ ; 713: 136573, 2020 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-31955087

RESUMO

Lignin is a highly complex, plant-derived natural biomass component, the analysis of which requires significant demands on the analytical platform. Fourier transform ion cyclotron mass spectrometry (FT-ICR MS) has been shown to be able to readily assess the complexity of lignin and lignin degradation products by assigning tens of thousands of compounds with elemental formulae. Nevertheless, many experimental and instrumental parameters introduce discrimination towards certain components, which limits the comprehensive MS analysis. As a result, a complete characterization of the lignome remains a challenge. The present study investigated a degraded lignin sample using FT-ICR MS and compared several atmospheric pressure ionization methods, e.g., electrospray ionization, atmospheric-pressure chemical ionization, and atmospheric-pressure photoionization. The results clearly show that the number of heteroatoms (e.g., N, S, P) in the sample greatly increases the chemical diversity of lignin, while at the same time also providing potentially useful biomarkers. We demonstrate here that FT-ICR MS was able to directly isolate isotopically pure single components from the ultra-complex mixture for subsequent structural analysis, without the time-consuming chromatographic separation. CAPSULE: Various ionization techniques coupled to FT-ICR MS provide a powerful tool to assess the lignome coverage.


Assuntos
Pressão Atmosférica , Lignina/química , Análise de Fourier , Íons , Espectrometria de Massas
4.
Arch Oral Biol ; 110: 104623, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31830639

RESUMO

OBJECTIVE: The aim of this study was to determine chlorhexidine retention in different oral sites after a one-time 30 s mouth rinsing. DESIGN: Five volunteers were asked to rinse their mouth with 10 ml of 0.2 % chlorhexidine digluconate for 30 s. After rinsing, samples were collected from the interdental area, buccal dental pellicle, anterior labial and posterior buccal mucosa, and saliva with a microbrush at five-time points within 24 h. Retention of chlorhexidine was measured using matrix-assisted laser desorption/ionization-time of flight mass spectrometry with a quantification limit of 15 ng/ml. RESULTS: Chlorhexidine remained in the oral cavity at micrograms per milliliter levels for 11 h after mouth rinsing and was even detected 24 h after application. The results showed a distinct decline of intraoral chlorhexidine levels during the first 6 h after rinsing and it was then retained at low concentrations for at least 24 h. CONCLUSIONS: The dental pellicle and oral mucosa were favorable sites for chlorhexidine retention. The novel method used for chlorhexidine determination offered excellent quantification limits and readily permitted quantification of chlorhexidine.


Assuntos
Clorexidina , Desinfetantes , Boca , Antissépticos Bucais , Clorexidina/farmacocinética , Desinfetantes/farmacocinética , Humanos , Boca/química , Mucosa Bucal/química , Antissépticos Bucais/farmacocinética , Saliva/química , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz
5.
Mol Psychiatry ; 25(2): 442-460, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30108314

RESUMO

Recurrent panic attacks (PAs) are a common feature of panic disorder (PD) and post-traumatic stress disorder (PTSD). Several distinct brain regions are involved in the regulation of panic responses, such as perifornical hypothalamus (PeF), periaqueductal gray, amygdala and frontal cortex. We have previously shown that inhibition of GABA synthesis in the PeF produces panic-vulnerable rats. Here, we investigate the mechanisms by which a panic-vulnerable state could lead to persistent fear. We first show that optogenetic activation of glutamatergic terminals from the PeF to the basolateral amygdala (BLA) enhanced the acquisition, delayed the extinction and induced the persistence of fear responses 3 weeks later, confirming a functional PeF-amygdala pathway involved in fear learning. Similar to optogenetic activation of PeF, panic-prone rats also exhibited delayed extinction. Next, we demonstrate that panic-prone rats had altered inhibitory and enhanced excitatory synaptic transmission of the principal neurons, and reduced protein levels of metabotropic glutamate type 2 receptor (mGluR2) in the BLA. Application of an mGluR2-positive allosteric modulator (PAM) reduced glutamate neurotransmission in the BLA slices from panic-prone rats. Treating panic-prone rats with mGluR2 PAM blocked sodium lactate (NaLac)-induced panic responses and normalized fear extinction deficits. Finally, in a subset of patients with comorbid PD, treatment with mGluR2 PAM resulted in complete remission of panic symptoms. These data demonstrate that a panic-prone state leads to specific reduction in mGluR2 function within the amygdala network and facilitates fear, and mGluR2 PAMs could be a targeted treatment for panic symptoms in PD and PTSD patients.

6.
J Mass Spectrom ; 54(11): 878-884, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31652368

RESUMO

Overcoming the detrimental effects of sweet spots during crystallization is an important step to improve the quantitative abilities of matrix-assisted laser desorption/ionization (MALDI) mass spectrometry. In this study, we introduce MALDI targets, which exhibit a channel design to reduce sweet spot phenomena and improve reproducibility. The size of the channels was 3.0 mm in length, 0.35 mm in depth, and 0.40 mm in width, adjusted to the width of the implemented laser beam. For sample deposition, the matrix/sample mixture was homogenously deposited into the channels using capillary action. To demonstrate the proof-of-principle, the novel plates were used for the quantification of acetyl-L-carnitine in human blood plasma using a combined standard addition and isotope dilution method. The results showed that the reproducibility of acetyl-L-carnitine detection was highly improved over a conventional MALDI-MS assay, with RSD values of less than 5.9% in comparison with 15.6% using the regular MALDI method. The limits of quantification using the new plates were lowered approximately two-fold in comparison with a standard rastering approach on a smooth stainless-steel plate. Matrix effects were also assessed and shown to be negligible. The new assay was subsequently applied to the quantification of acetyl-L-carnitine in human plasma samples.

7.
Obes Surg ; 29(12): 3928-3936, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31301032

RESUMO

BACKGROUND: Attitudes of the general public may be an influencing factor for low surgery rates: When skepticism is high, support for individuals wanting or needing to undergo surgery may diminish. This study assesses the relevance of barriers to metabolic surgery. METHODS: The study was conducted using a representative sample of the German population (n = 1007). Participants were asked to imagine that they would have to decide for or against metabolic surgery and rate how this decision would be influenced by a number of reasons given to them (Likert scale). Results are presented by weight status. RESULTS: The barrier found most irrelevant is that surgery could be considered cheating across all weight groups. About a fourth of the sample state that not knowing enough about surgery (28.5%), being afraid of surgery (28.3%), and potential negative consequences after surgery (24.5%) are reasons against metabolic surgery that were rated extremely relevant. Having obesity was a significant predictor of endorsement in two variables: feeling like cheating (lower probability for relevance, OR = 0.58, p = 0.025) and a lack of knowledge (lower probability for relevance, OR = 0.59, p = 0.031). CONCLUSIONS: In summary, the public's view of weight loss surgery lacks information about post-surgical consequences. It is important to address these points in the public and in social networks of patients as they may be pre- or antecedent of surgery stigma.

8.
Anal Bioanal Chem ; 411(23): 6031-6037, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31278551

RESUMO

Lignin is the most abundant natural resource of aromatic moieties and the second most abundant natural biopolymer. Analytical techniques that obtain as much information as possible on the exact structural content of lignin species are essential for developing efficient processes that transform highly complex lignin wastes into value chemicals and biofuels. For mass spectrometric analysis of lignin samples, usually electrospray ionization, atmospheric pressure chemical ionization, or atmospheric pressure photoionization are used as ionization techniques. Matrix-assisted laser desorption/ionization (MALDI) is less frequently applied but offers a much more rapid screening option for lignin mixtures. In this study, we compared several common MALDI matrices for analysis of alkali lignin and discovered that different chemical matrices exhibited very different ionization efficiencies and selectivity with respect to the structures of the lignin-related compounds as well as the presence of heteroatoms. Importantly, the results highlight that the choice of matrix strongly determines the analytical coverage of molecular species in the complex lignin degradation mixtures. Graphical abstract.


Assuntos
Lignina/química , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Nitrogênio/análise , Plantas/química , Enxofre/análise
9.
Cancers (Basel) ; 11(7)2019 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-31277415

RESUMO

Regulation of Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB)/Rel transcription factors (TFs) is extremely cell-type-specific owing to their ability to act disparately in the context of cellular homeostasis driven by cellular fate and the microenvironment. This is also valid for tumor cells in which every single component shows heterogenic effects. Whereas many studies highlighted a per se oncogenic function for NF-κB/Rel TFs across cancers, recent advances in the field revealed their additional tumor-suppressive nature. Specifically, pancreatic ductal adenocarcinoma (PDAC), as one of the deadliest malignant diseases, shows aberrant canonical-noncanonical NF-κB signaling activity. Although decades of work suggest a prominent oncogenic activity of NF-κB signaling in PDAC, emerging evidence points to the opposite including anti-tumor effects. Considering the dual nature of NF-κB signaling and how it is closely linked to many other cancer related signaling pathways, it is essential to dissect the roles of individual Rel TFs in pancreatic carcinogenesis and tumor persistency and progression. Here, we discuss recent knowledge highlighting the role of Rel TFs RelA, RelB, and c-Rel in PDAC development and maintenance. Next to providing rationales for therapeutically harnessing Rel TF function in PDAC, we compile strategies currently in (pre-)clinical evaluation.

10.
Contemp Clin Trials Commun ; 15: 100375, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31193565

RESUMO

Background: Pharmacokinetic (PK) and pharmacodynamic (PD) data on perioperative antibiotic prophylaxis or antibiotic therapy are rare in patients suffering from morbid obesity. Furthermore, dosing regimens should be based on PK/PD models that ensure effective antibiotic exposure not in plasma, but primarily at the site of infection, mostly in the interstitial fluid (ISF). The aim of this trial is to investigate whether current dosing regimens of various antibiotics lead to effective concentrations in the ISF of morbidly obese patients. Methods: We designed a prospective, parallel group, open-labeled, controlled single center trial to investigate the plasma and tissue pharmacokinetics of the antibiotics linezolid, meropenem, tigecycline, piperacillin/tazobactam, fosfomcyine, cefazolin, metronidazole and as secondary aim the analgesics metamizole and acetaminophen. Inclusion criteria comprise body mass index ≥35 kg/m2 for obese or between 18.5 and 30 kg/m2 for non-obese patients scheduled for elective abdominal surgery. For PK analysis, blood and microdialysate samples of subcutaneous tissue were collected 0-8 h after study drug administration. The primary endpoint is to investigate a possible dependency of the area-under-the-curve (AUC0-8) in the interstitial fluid on body weight and obesity with population based pharmacokinetic analysis. Discussion: Inadequate dosing regimes of antibiotics may be a relevant factor for morbidity and mortality of patients, as well as for the development of bacterial antibiotic resistance. The measurement of plasma and tissue concentrations will provide information necessary for PK/PD-modelling. These data about antibiotic PK/PDcharacteristics in soft tissue and their dependence on weight should help to develop weight-dependent models for calculation of patient's individual doses of different antibiotics. Trial registration: EU clinical trials register (EudraCT-No. 2012-004383-22) and German Clinical trials Register (DRKS00004776).

11.
Eat Weight Disord ; 2019 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-31154633

RESUMO

PURPOSE: The present study aimed to compare prevalence rates of childhood maltreatment between patients with severe obesity undergoing bariatric surgery and patients without a surgical procedure. Second purpose was to calculate the association between childhood maltreatment and outcomes 6 and 12 months after a bariatric procedure. METHODS: Childhood maltreatment was assessed using the Childhood Trauma Questionnaire (CTQ) and compared between 120 bariatric surgery patients and 346 non-surgery patients with severe obesity. For the bariatric surgery subgroup, linear mixed models with repeated measures were used to analyze the predictive value of childhood maltreatment on weight outcomes and psychopathology. Additionally, between- and within-group comparisons were calculated to compare patients with and without childhood maltreatment regarding BMI and weight loss (%TWL, %EWL), depression severity (BDI-II), eating disorder psychopathology (EDE-Q), and suicidal ideation (BSS), at baseline, 6- and 12-month assessment. RESULTS: Prevalence rates for childhood maltreatment, depression and suicidal ideation were significantly higher in non-surgery compared to bariatric surgery patients. Within the surgery group, no significant interaction effect between childhood maltreatment and time was found. Hence, childhood maltreatment did not impact the course of body weight, depression and eating disorder psychopathology from pre- to post-surgery. CONCLUSIONS: Significantly higher rates of childhood maltreatment were found within non-surgery patients with obesity in comparison to bariatric surgery patients. Childhood maltreatment did not predict poorer outcomes after surgery. Since history of childhood maltreatment may increase the risk for psychological disturbances, regular screening and, if necessary, psychological support should be offered to both groups. LEVEL OF EVIDENCE: Evidence obtained from well-designed cohort or case-control analytic studies, Level III. CLINICAL TRIAL REGISTRATION: Deutsches Register Klinischer Studien-German Clinical Trials Register: DRKS00003976.

12.
Anal Bioanal Chem ; 411(24): 6247-6253, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30972473

RESUMO

Gas phase ion/molecule reactions are often used in analytical applications to support the analysis of isomers or to identify specific functional groups of organic molecules. Until now, deliberate chemical reactions have not been performed in differential ion mobility spectrometry (DMS) devices except for hydrogen exchange and cluster formation. The present work extends that of Colorado and Brodbelt (Anal Chem 66:2330-5, 1994) on ion/molecule reactions in an ion trap mass spectrometer. In this study, class-specific chemical reactions of 4-quinolone antibiotics with various chemical reagents were used to demonstrate the analytical utility of ion/molecule reactions in a DMS drift cell. For these reactions, dehydrated reactive precursor ions were initially formed and made to undergo annulation reactions with selected reagents within the timescale of the DMS separation. Careful study of the energies required for dissociation of the adducts confirmed the covalent nature of the newly formed bond; thus demonstrating the analytical utility of this approach. Graphical abstract.

13.
Rapid Commun Mass Spectrom ; 33 Suppl 1: 1, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30447116
14.
Gastroenterology ; 156(1): 203-217.e20, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30296435

RESUMO

BACKGROUND AND AIMS: Cells in pancreatic ductal adenocarcinoma (PDAC) undergo autophagy, but its effects vary with tumor stage and genetic factors. We investigated the consequences of varying levels of the autophagy related 5 (Atg5) protein on pancreatic tumor formation and progression. METHODS: We generated mice that express oncogenic Kras in primary pancreatic cancer cells and have homozygous disruption of Atg5 (A5;Kras) or heterozygous disruption of Atg5 (A5+/-;Kras), and compared them with mice with only oncogenic Kras (controls). Pancreata were analyzed by histology and immunohistochemistry. Primary tumor cells were isolated and used to perform transcriptome, metabolome, intracellular calcium, extracellular cathepsin activity, and cell migration and invasion analyses. The cells were injected into wild-type littermates, and orthotopic tumor growth and metastasis were monitored. Atg5 was knocked down in pancreatic cancer cell lines using small hairpin RNAs; cell migration and invasion were measured, and cells were injected into wild-type littermates. PDAC samples were obtained from independent cohorts of patients and protein levels were measured on immunoblot and immunohistochemistry; we tested the correlation of protein levels with metastasis and patient survival times. RESULTS: A5+/-;Kras mice, with reduced Atg5 levels, developed more tumors and metastases, than control mice, whereas A5;Kras mice did not develop any tumors. Cultured A5+/-;Kras primary tumor cells were resistant to induction and inhibition of autophagy, had altered mitochondrial morphology, compromised mitochondrial function, changes in intracellular Ca2+ oscillations, and increased activity of extracellular cathepsin L and D. The tumors that formed in A5+/-;Kras mice contained greater numbers of type 2 macrophages than control mice, and primary A5+/-;Kras tumor cells had up-regulated expression of cytokines that regulate macrophage chemoattraction and differentiation into M2 macrophage. Knockdown of Atg5 in pancreatic cancer cell lines increased their migratory and invasive capabilities, and formation of metastases following injection into mice. In human PDAC samples, lower levels of ATG5 associated with tumor metastasis and shorter survival time. CONCLUSIONS: In mice that express oncogenic Kras in pancreatic cells, heterozygous disruption of Atg5 and reduced protein levels promotes tumor development, whereas homozygous disruption of Atg5 blocks tumorigenesis. Therapeutic strategies to alter autophagy in PDAC should consider the effects of ATG5 levels to avoid the expansion of resistant and highly aggressive cells.


Assuntos
Proteína 5 Relacionada à Autofagia/metabolismo , Autofagia , Carcinoma Ductal Pancreático/metabolismo , Movimento Celular , Neoplasias Pancreáticas/metabolismo , Animais , Proteína 5 Relacionada à Autofagia/deficiência , Proteína 5 Relacionada à Autofagia/genética , Carcinoma Ductal Pancreático/genética , Carcinoma Ductal Pancreático/prevenção & controle , Carcinoma Ductal Pancreático/secundário , Catepsinas/genética , Catepsinas/metabolismo , Proliferação de Células , Transformação Celular Neoplásica/genética , Transformação Celular Neoplásica/metabolismo , Transformação Celular Neoplásica/patologia , Progressão da Doença , Regulação Neoplásica da Expressão Gênica , Genes ras , Heterozigoto , Homozigoto , Camundongos Knockout , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/patologia , Neoplasias Pancreáticas/prevenção & controle , Transdução de Sinais , Carga Tumoral , Células Tumorais Cultivadas
15.
Anal Bioanal Chem ; 411(2): 353-365, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30417265

RESUMO

Multiple sclerosis (MS) is an immune-mediated neurodegenerative disease of the central nervous system (CNS). One of the most promising recent medications for MS is teriflunomide. Its primary mechanism of action is linked to effects on the peripheral immune system by inhibiting dihydroorotate dehydrogenase (DHODH)-catalyzed de novo pyrimidine synthesis and reducing the expansion of lymphocytes in the peripheral immune system. Some in vitro studies suggested, however, that it can also have a direct effect on the CNS compartment. This potential alternative mode of action depends on the drug's capacity to traverse the blood-brain barrier (BBB) and to exert an effect on the complex network of brain biochemical pathways. In this paper, we demonstrate the application of high-resolution/high-accuracy matrix-assisted laser desorption/ionization Fourier-transform ion cyclotron resonance mass spectrometry for molecular imaging of the mouse brain coronal sections from animals treated with teriflunomide. Specifically, in order to assess the effect of teriflunomide on the mouse CNS compartment, we investigated the feasibility of teriflunomide to traverse the BBB. Secondly, we systematically evaluated the spatial and semi-quantitative brain metabolic profiles of 24 different endogenous compounds after 4-day teriflunomide administration. Even though the drug was not detected in the examined cerebral sections (despite the high detection sensitivity of the developed method), in-depth study of the endogenous metabolic compartment revealed noticeable alterations as a result of teriflunomide administration compared to the control animals. The observed differences, particularly for purine and pyrimidine nucleotides as well as for glutathione and carbohydrate metabolism intermediates, shed some light on the potential impact of teriflunomide on the mouse brain metabolic networks. Graphical Abstract.


Assuntos
Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Crotonatos/farmacologia , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Toluidinas/farmacologia , Animais , Barreira Hematoencefálica , Crotonatos/química , Fatores Imunológicos/farmacologia , Camundongos , Estrutura Molecular , Toluidinas/química
16.
Rapid Commun Mass Spectrom ; 33 Suppl 1: 2-10, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30076644

RESUMO

Lignin is the second most abundant natural biopolymer and its wastes are significant sources for renewable chemicals as an alternative to conventional fossil fuels. Consequently, chemical characterization methods are required to assess the content of valuable chemicals contained in these complex lignin wastes. This short overview summarizes rapid data-processing methods developed in our laboratory for application to full-scan raw data from high-resolution mass spectrometry experiments of decomposed lignin samples. The discussed graphical and statistical methods support the initial classification and elucidation of the main structural features of the lignin components without the need for time-consuming tandem mass spectrometry analyses.


Assuntos
Lignina/análise , Lignina/química , Espectrometria de Massas/métodos , Interpretação Estatística de Dados , Oxirredução
17.
Anal Chem ; 90(21): 12592-12600, 2018 11 06.
Artigo em Inglês | MEDLINE | ID: mdl-30260620

RESUMO

Tissue-specific ion suppression is an unavoidable matrix effect in MALDI mass spectrometry imaging (MALDI-MSI), the negative impact of which on precision and accuracy in quantitative MALDI-MSI can be reduced to some extent by applying isotope internal standards for normalization and matrix-matched calibration routines. The detection sensitivity still suffers, however, often resulting in significant loss of signal for the investigated analytes. An MSI application considerably affected by this phenomenon is the quantitative spatial analysis of central nervous system (CNS) drugs. Most of these drugs are low molecular weight, lipophilic compounds, which exhibit inefficient desorption and ionization during MALDI using conventional polar acidic matrices (CHCA, DHB). Here, we present the application of the (2-[(2 E)-3-(4- tert-butylphenyl)-2-methylprop-2-enylidene]malononitrile) matrix for high sensitivity imaging of CNS drugs in mouse brain sections. Since DCTB is usually described as an electron-transfer matrix, we provide a rationale (i.e., computational calculations of gas-phase proton affinity and ionization energy) for an additional proton-transfer ionization mechanism with this matrix. Furthermore, we compare the extent of signal suppression for five different CNS drugs when employing DCTB versus CHCA matrices. The results showed that the signal suppression was not only several times lower with DCTB than with CHCA but also depended on the specific tissue investigated. Finally, we present the application of DCTB and ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry to quantitative MALDI imaging of the anesthetic drug xylazine in mouse brain sections based on a linear matrix-matched calibration curve. DCTB afforded up to 100-fold signal intensity improvement over CHCA when comparing representative single MSI pixels and >440-fold improvement for the averaged mass spectrum of the adjacent tissue sections.


Assuntos
Fármacos do Sistema Nervoso Central/análise , Nitrilos/química , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Animais , Química Encefálica , Calibragem , Fármacos do Sistema Nervoso Central/química , Clonidina/análise , Clonidina/química , Clozapina/análise , Clozapina/química , Interações Hidrofóbicas e Hidrofílicas , Imipramina/análise , Imipramina/química , Ketamina/análise , Ketamina/química , Limite de Detecção , Camundongos Endogâmicos C57BL , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/instrumentação , Xilazina/análise , Xilazina/química
18.
Front Immunol ; 9: 1878, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30158932

RESUMO

Pancreatic ductal adenocarcinoma (PDAC), as the most frequent form of pancreatic malignancy, still is associated with a dismal prognosis. Due to its late detection, most patients are ineligible for surgery, and chemotherapeutic options are limited. Tumor heterogeneity and a characteristic structure with crosstalk between the cancer/malignant cells and an abundant tumor microenvironment (TME) make PDAC a very challenging puzzle to solve. Thus far, targeted therapies have failed to substantially improve the overall survival of PDAC patients. Immune checkpoint inhibition, as an emerging therapeutic option in cancer treatment, shows promising results in different solid tumor types and hematological malignancies. However, PDAC does not respond well to immune checkpoint inhibitors anti-programmed cell death protein 1 (PD-1) or anti-cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) alone or in combination. PDAC with its immune-privileged nature, starting from the early pre-neoplastic state, appears to escape from the antitumor immune response unlike other neoplastic entities. Different mechanisms how cancer cells achieve immune-privileged status have been hypothesized. Among them are decreased antigenicity and impaired immunogenicity via both cancer cell-intrinsic mechanisms and an augmented immunosuppressive TME. Here, we seek to shed light on the recent advances in both bench and bedside investigation of immunotherapeutic options for PDAC. Furthermore, we aim to compile recent data about how PDAC adopts immune escape mechanisms, and how these mechanisms might be exploited therapeutically in combination with immune checkpoint inhibitors, such as PD-1 or CTLA-4 antibodies.


Assuntos
Antineoplásicos Imunológicos/uso terapêutico , Biomarcadores Tumorais/antagonistas & inibidores , Carcinoma Ductal Pancreático/tratamento farmacológico , Imunomodulação/efeitos dos fármacos , Terapia de Alvo Molecular , Neoplasias Pancreáticas/tratamento farmacológico , Animais , Antineoplásicos Imunológicos/administração & dosagem , Antineoplásicos Imunológicos/efeitos adversos , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Antígeno CTLA-4/antagonistas & inibidores , Carcinoma Ductal Pancreático/imunologia , Carcinoma Ductal Pancreático/patologia , Terapia Combinada , Humanos , Vigilância Imunológica , Imunoterapia , Neoplasias Pancreáticas/imunologia , Neoplasias Pancreáticas/patologia , Receptor de Morte Celular Programada 1/antagonistas & inibidores , Subpopulações de Linfócitos T/efeitos dos fármacos , Subpopulações de Linfócitos T/imunologia , Subpopulações de Linfócitos T/metabolismo , Falha de Tratamento , Resultado do Tratamento , Evasão Tumoral/efeitos dos fármacos , Evasão Tumoral/imunologia , Microambiente Tumoral/efeitos dos fármacos , Microambiente Tumoral/imunologia
19.
Chirurg ; 89(8): 583-588, 2018 Aug.
Artigo em Alemão | MEDLINE | ID: mdl-29974139

RESUMO

BACKGROUND: Sleeve gastrectomy is currently the most frequently performed bariatric procedure worldwide; however, with respect to a certain need for revisional surgery (due to reflux disease or weight regain) there is an ongoing discussion about the value of sleeve gastrectomy in terms of a stand-alone procedure. OBJECTIVE: The aim of this article is to critically discuss whether sleeve gastrectomy can still be considered a stand-alone procedure. MATERIAL AND METHODS: The current literature was searched for results after sleeve gastrectomy and the recommendations regarding this procedure are discussed. RESULTS: Currently approximately 50% of primary bariatric procedures are sleeve gastrectomies, which has become a well-established stand-alone procedure. Sleeve gastrectomy leads to good mid-term results; however, the results of the Roux-en-Y gastric bypass are comparatively superior in terms of type 2 diabetes remission, control of preexisting or de novo reflux disease and weight loss. The mortality is comparable; however, the morbidity is lower after sleeve gastrectomy but there is a relevant rate of fistulas of the stapler suture. CONCLUSION: Patients considered for sleeve gastrectomy must be informed of the procedure-specific risks, including the unforeseeable need for revision or redo surgery firstly due to weight regain or failing to reach the individual therapy target and secondly for worsening of a preexisting or de novo reflux disease.


Assuntos
Diabetes Mellitus Tipo 2 , Gastrectomia , Derivação Gástrica , Laparoscopia , Obesidade Mórbida , Diabetes Mellitus Tipo 2/complicações , Seguimentos , Humanos , Obesidade Mórbida/complicações , Obesidade Mórbida/cirurgia , Estudos Retrospectivos , Resultado do Tratamento , Perda de Peso
20.
J Dairy Sci ; 101(9): 8135-8145, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30007809

RESUMO

Group housing and computerized feeding of preweaned dairy calves are gaining in popularity among dairy producers, yet disease detection remains a challenge for this management system. The aim of this study was to investigate the application of statistical process control charting techniques to daily average feeding behavior to predict and detect illness and to describe the diagnostic test characteristics of using this technique to find a sick calf compared with detection by calf personnel. This prospective cross-sectional study was conducted on 10 farms in Minnesota (n = 4) and Virginia (n = 6) utilizing group housing and computerized feeding from February until October 2014. Calves were enrolled upon entrance to the group pen. Calf personnel recorded morbidity and mortality events. Farms were visited either every week (MN) or every other week (VA) to collect calf enrollment data, computer-derived feeding behavior data, and calf personnel-recorded calf morbidity and mortality. Standardized self-starting cumulative sum (CUSUM) charts were generated for each calf for each daily average feeding behavior, including drinking speed (mL/min), milk consumption (L/d), and visits to the feeder without a milk meal (no.). A testing subset of 352 calves (176 treated, 176 healthy) was first used to find CUSUM chart parameters that provided the highest diagnostic test sensitivity and best signal timing, which were then applied to all calves (n = 1,052). Generalized estimating equations were used to estimate the diagnostic test characteristics of a single negative mean CUSUM chart signal to detect a sick calf for a single feeding behavior. Combinations of feeding behavior signals were also explored. Single signals and combinations of signals that included drinking speed provided the most sensitive and timely signal, finding a sick calf up to an average (±SE) of 3.1 ± 8.8 d before calf personnel. However, there was no clear advantage to using CUSUM charting over calf observation for any one feeding behavior or combination of feeding behaviors when predictive values were considered. The results of this study suggest that, for the feeding behaviors monitored, the use of CUSUM control charts does not provide sufficient sensitivity or predictive values to detect a sick calf in a timely manner compared with calf personnel. This approach to examining daily average feeding behaviors cannot take the place of careful daily observation.


Assuntos
Doenças dos Bovinos/epidemiologia , Comportamento Alimentar , Abrigo para Animais , Animais , Bovinos , Doenças dos Bovinos/prevenção & controle , Estudos Transversais , Minnesota , Estudos Prospectivos , Virginia
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