Small Molecules Originated from Tryptophan and their Clinical Significance as Potential Biomarkers.

Background: L-tryptophan is an essential amino acid necessary for the human body to function. Its degradation occurs through two metabolic pathways. Approximately 95 % of the Ltryptophan available in the body is converted via the kynurenine pathway, while the remainder is degraded via the serotonin pathway.

The critical evaluation of the effects of imidazolium-based ionic liquids on the separation efficiency of selected biogenic amines and their metabolites during MEKC analysis.

Ionic liquids (ILs) such as imidazole can be used to prevent the sorption of analytes onto the quartz walls of the capillary. Coating the capillary wall with a cation layer increases its surface stability, consequently improving the repeatability of separation process. Currently, examining the effects of dynamic coatings on the capillary wall is an emerging trend in capillary electrophoresis (CE) research.

Facile and highly efficient three-phase single drop microextraction in-line coupled with capillary electrophoresis.

A high-performance version of in-line, three-phase direct immersion-single drop microextraction (DI-SDME) coupled with capillary electrophoresis (CE) was demonstrated using a commercial CE instrument, and all the major and minor details were described to provide an easy-to-follow and user-friendly protocol. The excellent sample cleanup and enrichment power of this method was demonstrated with nonsteroidal anti-inflammatory drugs (NSAIDs) in human urine. The only preparation of urine samples was the addition of HCl to acidify the urine sample to pH 2.

Evaluation of Analytes Characterized with Potential Protective Action after Rat Exposure to Lead.

Lead (Pb) was revealed for its role as a neurodevelopmental toxin. The determination of neurotransmitters (NTs) in particular brain regions could ameliorate the precise description and optimization of therapeutic protocols able to restore the harmony of signaling pathways in nervous and immune systems. The determination of selected analytes from the group of NTs based on the liquid chromatography (LC)-based method was carried out to illustrate the changes of amino acid (AA) and biogenic amine (BA) profiles observed in chosen immune and nervous systems rat tissues after Pb intoxication.

Sensitive Analysis of Idarubicin in Human Urine and Plasma by Liquid Chromatography with Fluorescence Detection: An Application in Drug Monitoring.

A new approach for the sensitive, robust and rapid determination of idarubicin (IDA) in human plasma and urine samples based on liquid chromatography with fluorescence detection (LC-FL) was developed. Satisfactory chromatographic separation of the analyte after solid-phase extraction (SPE) was performed on a Discovery HS C18 analytical column using a mixture of acetonitrile and 0.1% formic acid in water as the mobile phase in isocratic mode.

Health Benefits of Plant-Derived Sulfur Compounds, Glucosinolates, and Organosulfur Compounds.

The broad spectrum of the mechanism of action of immune-boosting natural compounds as well as the complex nature of the food matrices make researching the health benefits of various food products a complicated task. Moreover, many routes are involved in the action of most natural compounds that lead to the inhibition of chronic inflammation, which results in a decrease in the ability to remove a pathogen asymptomatically and is connected to various pathological events, such as cancer. A number of cancers have been associated with inflammatory processes.

Selected Matrix Metalloproteinases (MMP-2, MMP-7) and Their Inhibitor (TIMP-2) in Adult and Pediatric Cancer.

The tumor microenvironment (TME) consists of numerous biologically relevant elements. One of the most important components of the TME is the extracellular matrix (ECM). The compounds of the ECM create a network that provides structural and biochemical support to surrounding cells.

Extraction and preconcentration of compounds from the l-tyrosine metabolic pathway prior to their micellar electrokinetic chromatography separation.

The prominent biological effects of adrenaline (A), noradrenaline (NA) and dopamine (DA) as well as the clinical importance of their metabolites (such as dihydroxyphenylacetic acid (DOPAC), methoxy‑4-hydroxyphenyl glycol (MHPG), dihydroxyphenylglycol (DHPG), metanephrine (M), normetanephrine (NM), vanillylmandelic acid (VMA), homovanillic acid (HVA)) have forced researchers to evaluate new analytical methodologies for their isolation and preconcentration from biological samples. For this reason, the three most popular extraction techniques (dispersive liquid-liquid microextraction (DLLME), solid-phase extraction (SPE), solid-phase microextraction (SPME)) were tested. Micellar electrokinetic chromatography (MEKC) - a mode of capillary electrophoresis - with a diode array detector (DAD) was applied to assess the extraction efficiency.

Development and validation of a high-performance liquid chromatographic method with a fluorescence detector for the analysis of epirubicin in human urine and plasma, and its application in drug monitoring.

The aim of the work was to develop a simple, sensitive and accurate liquid chromatography with fluorescence detection (LC-FL) method for the determination of epirubicin in human urine and plasma. Solid phase extraction with HLB cartridges and mixture of dichloromethane:2-propanol:methanol (2:1:1, v/v/v) as the eluent, was used to prepare the samples. The chromatographic analysis was carried out on a Synergi Hydro-RP column with a mobile phase consisting of 40 mM phosphate buffer (pH 4.

Green Chemistry Extractions of Carotenoids from L.-Supercritical Carbon Dioxide and Enzyme-Assisted Methods.

Multiple reviews have been published on various aspects of carotenoid extraction. Nevertheless, none of them focused on the discussion of recent green chemistry extraction protocols, especially for the carotenoids extraction from L. This group of bioactive compounds has been chosen for this review since most of the scientific papers proved their antioxidant properties relevant for inflammation, stress-related disorders, cancer, or neurological and neurodegenerative diseases, such as stroke and Alzheimer's Disease.

MMP-14 degrades tropoelastin and elastin.

Matrix metalloproteinases are a class of enzymes, which degrade extracellular matrix components such as collagens, elastin, laminin or fibronectin. So far, four matrix metalloproteinases have been shown to degrade elastin and its precursor tropoelastin, namely matrix metalloproteinase-2, -7, -9 and -12. This study focuses on investigating the elastinolytic capability of membrane-type 1 matrix metalloproteinase, also known as matrix metalloproteinase-14.

Application of SPME supported by ionic liquids for the determination of biogenic amines by MEKC in clinical practice.

The analysis of biogenic amines (BAs) and their metabolites is helpful for the diagnosis of central nervous system disorders and other neuroendocrine and cancer disturbances. In the study, a developed micellar electrokinetic chromatography method, coupled with diode array detection (MEKC-DAD), was validated to monitor levels of adrenaline (A), noradrenaline (NA), dopamine (DA), L-Tryptophan (L-Tryp) and L-Tyrosine (L-Tyr) in real human urine samples. These neurotransmitters were isolated from urine samples using solid-phase microextraction (SPME) and methanol containing 1-ethyl-3-methylimidazolium tetrafluoroborate ionic liquid as the desorption phase.

Recent Trends in the Quantification of Biogenic Amines in Biofluids as Biomarkers of Various Disorders: A Review.

Biogenic amines (BAs) are bioactive endogenous compounds which play a significant physiological role in many cell processes like cell proliferation and differentiation, signal transduction and membrane stability. Likewise, they are important in the regulation of body temperature, the increase/decrease of blood pressure or intake of nutrition, as well as in the synthesis of nucleic acids and proteins, hormones and alkaloids. Additionally, it was confirmed that these compounds can be considered as useful biomarkers for the diagnosis, therapy and prognosis of several neuroendocrine and cardiovascular disorders, including neuroendocrine tumours (NET), schizophrenia and Parkinson's Disease.

Combination of field amplified sample injection and hydrophobic interaction electrokinetic chromatography (FASI-HIEKC) as a signal amplification method for the determination of selected macrocyclic antibiotics.

In this study, a field amplified sample injection (FASI) and hydrophobic interaction electrokinetic chromatography (HIEKC) method has been developed for the separation of five macrolide antibiotics: spiramycin, ivermectin, tylosin, josamycin, rapamycin, and one ansamycin drug - rifamycin. By the manipulation of both the sample and separation buffer compositions, their pH values and molarity, a systematic approach has been achieved to maximize analyte differential electrophoretic mobility and signal amplification. The impact of the sample solution composition and the injection mode on the signal amplification effect of the six tested antibiotics was also investigated.

Application of solid-phase microextraction in current biomedical research.

Extraction of endogenous compounds and drugs and their corresponding metabolites from complex matrices, such as biofluids and solid tissues, requires adequate analytical approach facilitating qualitative and quantitative analysis. To this end, solid-phase microextraction has been introduced as modern technology that is capable of efficient and high-throughput extraction of compounds due to its ability to amalgamate sampling, extraction, and pre-concentration steps, while requiring minimal use of organic solvents. The ability of solid-phase microextraction to enable analyses on small-volume biological samples and growing availability of biocompatible solid-phase microextraction coatings make it a highly useful technology for variety of applications.

Simultaneous electrokinetic and hydrodynamic injection and sequential stacking featuring sweeping for signal amplification following MEKC during the analysis of rapamycin (sirolimus) in serum samples.

Simultaneous electrokinetic and hydrodynamic injection of rapamycin (sirolimus) with off-line and online sample preconcentration techniques and using MEKC has been studied. Compared to conventional hydrodynamic injection, a 168-fold improvement in the signal was obtained with a combination of simultaneous electrokinetic and hydrodynamic injectionand field enhanced sample injection in conjunction with a sweeping technique called sequential stacking featuring sweeping. However, the coupling of the developed electrophoretic method and solid-phase microextraction allowed the signal intensity to increase more than 231 times.

Optimization of LC method for the quantification of doxorubicin in plasma and urine samples in view of pharmacokinetic, biomedical and drug monitoring therapy studies.

A simple, rapid, reliable and sensitive method based on liquid chromatography with fluorescence detection (LC-FL) for the quantification of doxorubicin (DOX) in human plasma and urine samples was developed. The assay was carried out after the solid-phase extraction procedure (SPE) with hydrophilic-lipophilic balance (HLB) cartridges, and with daunorubicin hydrochloride (DAU) used as the internal standard. Chromatographic separation was performed on a Discovery HS C18 column in isocratic elution mode, and the detection of the analytes set at excitation and emission wavelengths of 487 and 555 nm, respectively.

Comparison of Three Extraction Approaches for the Isolation of Neurotransmitters from Rat Brain Samples.

The determination of neurotransmitters (NTs) as relevant potential biomarkers in the study of various central nervous system (CNS) pathologies has been demonstrated. Knowing that NTs-related diseases mostly occupy individual regions of the nervous system, as observed, for instance, in neurodegenerative diseases (Alzheimer’s and Parkinson’s Diseases), the analysis of brain slices is preferred to whole-brain analysis. In this report, we present sample preparation approaches, such as solid-phase extraction, solid-phase microextraction, and dispersive liquid⁻liquid microextraction, and discuss the pitfalls and advantages of each extraction method.

Ionic liquids as signal amplifiers for the simultaneous extraction of several neurotransmitters determined by micellar electrokinetic chromatography.

Nowadays, ionic liquids (ILs) are receiving more attention in various fields of analytical chemistry. Their contribution to the enhancement of the clean-up, extraction, separation and determination of trace amounts of various biologically important compounds in distinct matrices is well documented. Moreover, their importance as "green chemistry" solvents has been pointed out.

Practical Application of Biogenic Amine Profiles for the Diagnosis of Patients with Ischemic Stroke.

Background: Ischemic stroke (IS) is still one of the major issues in medicine. Still, early diagnosis and misdiagnosis remain the main barriers for proper patient treatment and follow-up. Exploring new potential diagnostic biomarkers for IS is relevant to decrease patient morbidity and the occurrence of poststroke diseases.

HILIC-MS Rat Brain Analysis, A New Approach for the Study of Ischemic Attack.

Clinicians often rely on selected small molecular compounds from body fluids for the detection, screening or monitoring of numerous life-threatening diseases. Among others, important monoamines - biogenic amines (BAs) - and their metabolites serve as sensitive biomarkers to study the progression or even early detection of on-going brain pathologies or tumors of neuroendocrine origins. Undertaking the task to optimize a reliable method for the simultaneous analysis of the most relevant BAs in biological matrices is of utmost importance for scientists.

Determination of urinary biogenic amines' biomarker profile in neuroblastoma and pheochromocytoma patients by MEKC method with preceding dispersive liquid-liquid microextraction.

The unbalanced secretion of biogenic amines (BAs) is considered to be a relevant biochemical biomarker in the screening for neuroendocrine tumors, such as: neuroblastoma and pheochromocytoma. However, there is still a need to improve the bioanalytical procedures for BA determination in biological samples due to their instability (photo- and thermosensitivity, easy oxidation) and low concentration in the body fluids. In this study, the primary analytical challenge was to optimize the method of extraction of seven compounds from among BAs and their precursors from urine samples.

Non-invasive screening for neuroendocrine tumors-Biogenic amines as neoplasm biomarkers and the potential improvement of "gold standards".

Early, noninvasive diagnosis of tumors is relevant, especially for rare, often asymptomatic, thus - hard to detect in curable stages of the disease - tumors, as neuroendocrine tumors (NET). To avoid or supplement the NET management via application of invasive biopsy or expensive imagining techniques, the biochemical evaluation of biomarkers from easy accessible body fluids could be the great, potential diagnostic or prognostic tool. Nevertheless, already existed biochemical diagnostic tools for NET must be improved.

Cyclodextrin-modified MEKC method for quantification of selected acidic metabolites of catecholamines in the presence of various biogenic amines. Application to diagnosis of neuroblastoma.

The main aim of the presented study was to develop a reliable and non-time-consuming method for the simultaneous separation of biogenic amines (BAs) like noradrenalin, adrenalin, dopamine and their main metabolites - homovanillic acid (HVA), vanillylmandelic acid (VMA), 3,4-dihydroxyphenylacetic acid (DOPAC) - in urine samples. To achieve this, the validated α-cyclodextrin (α-CD)-modified micellar electrokinetic chromatography method with DAD was proposed. The optimized separation parameters were as follows: background electrolyte was composed of 10mM sodium tetraborate decahydrate, 30mM SDS, 15% (v/v) methanol and 25mM α-CD, adjusted to pH 9.

Gel electrophoretic separation of proteins from cultured neuroendocrine tumor cell lines.

Neuroendocrine tumors (NET) often develop asymptomatically and are detected at a late stage. Currently, there exist certain markers of NET that occur only in the advanced stages of the disease. Still, there is need to develop markers specific of the early stage of cancer development.