Plasma tryptophan pathway metabolites quantified by liquid chromatography-tandem mass spectrometry as biomarkers in neuroendocrine tumor patients.

A good and accessible biomarker is of great clinical value in neuroendocrine tumor (NET) patients, especially considering its frequently indolent nature and long-term follow-up. Plasma chromogranin A (CgA) and 5-hydroxyindoleacetic acid (5-HIAA) are currently used as biomarkers in NET, but their sensitivity and specificity are restricted. 5-HIAA is the main metabolite of serotonin, an important neurotransmitter of the tryptophan pathway. The aim of this study is to estabish a sensitive and accurate method for the quantification of tryptophan pathway metabolites in plasma. We further aimed to evaluate its utility as a clinical tool in NET disease. We obtained plasma samples from NET patients and healthy controls recruited from the University Hospital of North Norway, Tromsø. Samples were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS), and eight metabolites of the tryptophan pathway were quantified. We included 130 NET patients (72/130 small intestinal [SI] NET, 35/130 pancreatic NET, 23/130 other origin) and 20 healthy controls. In the SI-NET group, 26/72 patients presented with symptoms of carcinoid syndrome (CS). We found that combining tryptophan metabolites into a serotonin/kynurenine pathway ratio improved diagnostic sensitivity (92.3%) and specificity (100%) in detecting CS patients from healthy controls compared with plasma 5-HIAA alone (sensitivity 84.6%/specificity 100%). Further, a clinical marker based on the combination of plasma serotonin, 5-HIAA, and 5OH-tryptophan, increased diagnostic capacity identifying NET patients with metastasized disease from healthy controls compared with singular plasma 5-HIAA, serotonin, or CgA. In addition, this marker was positive in 61% of curatively operated SI-NET patients compared with only 10% of healthy controls (p < .001). Our results indicate that simultaneous quantification of several tryptophan metabolites in plasma, using LC-MS/MS, may represent a clinically useful diagnostic tool in NET disease.

Rapid and sensitive HPLC-MS/MS method for the quantification of dopamine, GABA, serotonin, glutamine and glutamate in rat brain regions after exposure to tobacco cigarettes.

Tobacco smoking is a preventable main cause of fatal diseases. Accurate measurements of the effects it has on neurotransmitters are essential in developing new strategies for smoking cessation. Moreover, measurements of neurotransmitter levels can aid in developing drugs that counteract the effects of smoking. The aim of this study is to develop and validate a fast, simultaneous and sensitive method for measuring the levels of neurotransmitters in rat brain after the exposure of tobacco cigarettes. The selected neurotransmitters include dopamine, GABA, serotonin, glutamine and glutamate. The method is based on high-performance liquid chromatography-tandem mass spectrometry. Chromatographic separation was achieved within 3 min using a Zorbax SB C18 column (3.0 × 100 mm, 1.8 µm particle size). The mobile phase consisted of HPLC-grade water and acetonitrile each containing 0.3% heptafluorobutyric acid and 0.5% formic acid at gradient conditions. The linear range was 0.015-0.07, 825-7,218, 140-520, 63.42-160.75 and 38.25 × 103 to 110.35 × 103  ng/ml for dopamine, GABA, serotonin, glutamine and glutamate, respectively. Inter- and intra-run accuracy were in the range 97.82-103.37% with a precision (CV%) of ≤0.90%. The results revealed that 4 weeks of cigarette exposure significantly increased neurotransmitter levels after exposure to tobacco cigarettes in various brain regions, including the hippocampus and the amygdala. This increase in neurotransmitters levels may in turn activate the nicotine dependence pathway.

Gastroesophageal tube of the Iguana iguana (Iguanidae): histological description, histochemical and immunohistochemical analysis of 5-HT and SS cells / Tubo gastroesofágico da Iguana iguana (Iguanidae): descrição histológica, histoquímica e análise imunohistoquímica de células 5-HT e SS

The work aims were to describe the histological and histochemical structure of the gastroesophageal tube of Iguana iguana and verify the occurrence and distribution of immunoreactive serotonin (5-HT) and somatostatin (SS) cells. Fragments of the gastrointestinal tract (GIT) of five iguanas were which underwent standard histological and immunohistochemistry technique. Immunoreactive cells for 5-HT and SS were quantified using the STEPanizer. The oesophagus has ciliated columnar pseudostratified epithelium with staining Alcian blue (AB) + and goblet cells highly reactive to periodic acid Schiff (PAS). In the cervical oesophagus, the numerical density of 5-HT cells per unit area (QA [5-HT cells]/µm2) was 4.6x10-2 ± 2.0 and celomatic oesophagus presented QA = 4.0x10-2 ± 1.0. The epithelium of the stomach is simple columnar, PAS and AB +. The cranial and middle regions of the stomach presented (QA [5-HT cells]/µm2) = 6.18x10-2 ± 3.2 and the caudal region, QA = 0.6x10-2 ± 0.2. The SS cells were only observed in the caudal stomach, with numerical density (QA [SS cells]/µm2) = 1.4x10-2 ± 0.9 In I. iguana, variation was observed in terms of the distribution of mucus secretions and the pattern of occurrence of serotonin and somatostatin-secreting enteroendocrine cells in the TGI, which possibly will result in an interspecific adaptive response.

Os objetivos do trabalho foram descrever a estrutura histológica e histoquímica do tubo gastroesofágico da Iguana iguana e verificar a ocorrência e distribuição de células serotonina (5-HT) e somatostatina (SS) imunorreativas. Fragmentos do trato gastrointestinal (TGI) de cinco iguanas foram submetidos à técnica histológica e imunohistoquímica padrão. As células imunorreativas para 5-HT e SS foram quantificadas usando o STEPanizer. O esôfago apresenta epitélio pseudoestratificado colunar ciliado Alcian blue (AB) positivo, com células caliciformes altamente reativas ao ácido periódico de Schiff (PAS). No esôfago cervical, a densidade numérica de células 5-HT por unidade de área (QA [células 5-HT] / µm2) foi de 4.6x10-2 ± 2.0 e o esôfago celomático apresentou QA = 4.0x10-2 ± 1.0. O epitélio do estômago é colunar simples, PAS e AB positivo. As regiões cranial e média do estômago apresentaram (QA [células 5-HT] / µm2) = 6.18x10-2 ± 3.2 e a região caudal, QA = 0.6x10-2 ± 0.2. As células SS foram observadas apenas no estômago caudal, com densidade numérica (QA [células SS] / µm2) = 1.4x10-2 ± 0.9. Em I. iguana, foi observada variações em termos da distribuição das secreções de muco e padrão de ocorrência das células enteroendócrinas secretoras de serotonina e somatostatina no TGI, o que possivelmente reflete uma resposta adaptativa interespecifica.

Enteropathogenic infections modulate intestinal serotonin transporter (SERT) function by activating Toll-like receptor 2 (TLR-2) in Crohn's disease.

Serotonin (5-hydroxytryptamine [5-HT]) is an intestinal neuromodulator that regulates several essential enteric physiological functions such as absorption or secretion of fluids, and peristaltic reflexes. Availability of the intestinal 5-HT is dependent on serotonin transporter (SERT), which uptakes 5-HT and facilitates its degradation. Interestingly, Toll-like receptor 2 (TLR-2) is co-localized with 5-HT, which suggests a possible impact of neuroendocrine cells in the inflammatory response through TLR-2 activation. Serum 5-HT levels were measured in 80 Crohn's disease (CD) patients and 40 healthy control subjects. Additionally, fully differentiated Caco-2 monolayers were infected with Mycobacteria paratuberculosis (MAP), L. monocytogenes, or M. smegmatis in the presence of exogenous 5-HT at different concentrations. Cells were subsequently harvested and used for measuring SERT activity, RNA isolation followed by RT-PCR, protein quantification, and tissue damage markers (DHE, LDH, GSH and MDA). TLR-2 intracellular signaling pathways were assessed by pre-incubating Caco-2 monolayers with selective blockers of ERK, cAMP/PKA, p38 MAPK, and 5-HT3 receptors. MAP-infected CD patients (N = 40) had higher serum 5-HT levels (462.95 ± 8.55 ng/mL, N = 40) than those without MAP infection (385.33 ± 10.3 ng/mL, N = 40). TLR-2 activation by enteropathogenic bacteria inhibited SERT activity in the presence of exogenous 5-HT by up to 50%. These effects were increasing gradually over 72 h, and MAP infection had the greatest effect on SERT inhibition when cells were exposed to 5-HT in a concentration dependent manner. Additionally, inhibition of SERT activity was accompanied with higher levels of pro-inflammatory cytokines (TNF-α, IL-6, IL-8) and oxidative stress markers (DHE, LDH and MDA), whereas SERT expression and protein level were downregulated. Consequently, inhibition of TLR-2 and p38 MAPK signaling or blocking 5-HT3 receptors restored SERT activity and reduced the production of pro-inflammatory cytokines, as reflected by the downregulation of oxidative stress and tissue damage markers. The involvement of TLR-2 in the intestinal pathology might be concluded not only from its innate immune role, but also from its effect on modulating the intestinal serotonergic response. Ultimately, regulating the intestinal serotonergic system can be therapeutically exploited to mitigate other enteropathogenic infections, which will help in understanding the gut-microbiome-brain connection.

Improvement Effects of Myelophil on Symptoms of Chronic Fatigue Syndrome in a Reserpine-Induced Mouse Model.

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is associated with various symptoms, such as depression, pain, and fatigue. To date, the pathological mechanisms and therapeutics remain uncertain. The purpose of this study was to investigate the effect of myelophil (MYP), composed of Astragali Radix and Salviaemiltiorrhizae Radix, on depression, pain, and fatigue behaviors and its underlying mechanisms. Reserpine (2 mg/kg for 10 days, intraperitoneally) induced depression, pain, and fatigue behaviors in mice. MYP treatment (100 mg/kg for 10 days, intragastrically) significantly improved depression behaviors, mechanical and thermal hypersensitivity, and fatigue behavior. MYP treatment regulated the expression of c-Fos, 5-HT1A/B receptors, and transforming growth factor ß (TGF-ß) in the brain, especially in the motor cortex, hippocampus, and nucleus of the solitary tract. MYP treatment decreased ionized calcium binding adapter molecule 1 (Iba1) expression in the hippocampus and increased tyrosine hydroxylase (TH) expression and the levels of dopamine and serotonin in the striatum. MYP treatment altered inflammatory and anti-oxidative-related mRNA expression in the spleen and liver. In conclusion, MYP was effective in recovering major symptoms of ME/CFS and was associated with the regulation of dopaminergic and serotonergic pathways and TGF-ß expression in the brain, as well as anti-inflammatory and anti-oxidant mechanisms in internal organs.

Multiplexing neurochemical detection with carbon fiber multielectrode arrays using fast-scan cyclic voltammetry.

Carbon fiber microelectrodes (CFMEs) have been extensively used to measure neurotransmitters with fast-scan cyclic voltammetry (FSCV) due to their ability to adsorb cationic monoamine neurotransmitters. Although FSCV, in tandem with CFMEs, provides high temporal and spatial resolution, only single-channel potentiostats and electrodes have been primarily utilized. More recently, the need and use of carbon fiber multielectrode arrays has risen to target multiple brain regions. Previous studies have shown the ability to detect dopamine using multielectrode arrays; however, they are not readily available to the scientific community. In this work, we interfaced a carbon fiber multielectrode array (MEA or multielectrode array), to a commercially available four-channel potentiostat for multiplexing neurochemical measurements. The MEA's relative performance was compared to single CFMEs where dopamine detection was found to be adsorption controlled to the electrode's surface. Multiple waveforms were applied to each fiber of the multielectrode array simultaneously to detect different analytes on each electrode of the array. A proof of concept ex vivo experiment showed that the multielectrode array could record redox activity in different areas within the mouse caudate putamen and detect dopamine in a 3-mm2 area. To our knowledge, this is the first use of the multielectrode array paired with a commercially available multichannel potentiostat for multi-waveform application and neurotransmitter co-detection. This novel array may aid in future studies to better understand complex brain heterogeneity, the dynamic neurochemical environment, and how disease states or drugs affect separate brain areas concurrently. Graphical abstract.

Alteration of intrapancreatic serotonin, homocysteine, TNF-α, and NGF levels as predisposing factors for diabetes following exposure to 900-MHz waves.

Exposure to mobile phone radiation causes deleterious health effects on biological systems. The objects of this study were to investigate the effect of 900-MHz radiofrequency waves (RFW) emitted from base transceiver station antenna on intrapancreatic homocysteine (Hcy), tumor necrosis factor-α (TNF-α), and nerve growth factor (NGF) as predisposing factors involved in pancreatic beta cell damage. Thirty male rats (Sprague-Dawley, 200 ± 10 g) were randomly divided into the control (without any exposure) and exposed groups: short time (2 h/day), long time (4 h/day), and exposed to 900-MHz RFW for 30 consecutive days. On the last days of the experiment, animals were killed and pancreas tissue was dissected out for evaluation of serotonin, Hcy, TNF-α, and NGF. There was a significant decrease in the serotonin and NGF levels in the pancreatic tissue of exposed groups compared to the control group (p < 0.05). Also, the levels of serotonin and NGF in the long-time exposure were significantly lower than the short-time exposure (p < 0.05). However, levels of Hcy and TNF-α were significantly increased in the pancreas of exposed groups compared to the control groups (p < 0.05). Exposure to 900-MHz RFW decreased pancreatic NGF and serotonin levels and increased the proinflammatory markers (Hcy and TNF-α), which can be a predisposing factor for type 2 diabetes.

Enhanced response of sensor on serotonin using nickel-reduced graphene oxide by atomic layer deposition.

Atomic layer deposition (ALD) is a promising method for preparing nanomaterials. The thickness and uniformity of nanomaterials can be precisely controlled. Hence, the uniform Ni nanoparticles (Ni NPs) deposited on reduced graphene oxide (rGO) by ALD and got the optimal combination interface. The morphology, structure, and electrochemical behavior of Ni NPs-rGO nanocomposite are investigated. By experiment results, the Ni NPs could occupy some active surface of rGO, resulting in high conductivity and large specific surface area of Ni NPs-rGO nanocomposite. The Ni NPs-rGO nanocomposite exhibits high electrocatalytic activity for serotonin and speeds up the electron transfer between the surface of the electrode and the solution. Therefore, the sensor is prepared by Ni NPs-rGO nanocomposite modified glassy carbon electrode (GCE) and used to sensitive detection of serotonin. By differential pulse voltammetric, the Ni NPs-rGO/GCE enhanced the current responses and showed a wide linear range of 0.02-2 µM with a low detection of 0.01 µM for serotonin (S/N = 3). The Ni NPs-rGO/GCE exhibited good stability, selectivity, and anti-interference ability that can be used for real sample detection. According to these results, the Ni NPs-rGO nanocompositeis successfully prepared by ALD. The properties of Ni NPs-rGO nanocomposite make it an attractive material for potential applications in sensors and catalysis.

Tetraphenylpyrazine-Based Luminescent Metal-Organic Framework for Chemical Sensing of Carcinoids Biomarkers.

A new non-interpenetrated three-dimensional (3D) pillared-layered TPP-based LMOF [Zn3(TPyTPP)0.5(BDC)3]·8DMF (denoted as Zn-MOF 1) was successfully prepared (TPyTPP = tetrakis(4-(pyridin-4-yl)phenyl)pyrazine and H2BDC = 1,4-benzenedicarboxylic acid). Zn-MOF 1 was characterized by single-crystal X-ray diffraction, PXRD, IR, N2 adsorption, thermogravimetric analysis, and luminescent spectrum. Impressively, luminescent sensing studies reveal that activated Zn-MOF 1 not only displays excellent luminescence-quenching efficiency with the values of high Ksv and low LODs toward 5-hydroxytryptamine (5-HT) and 5-hydroxyindole-3-acetic acid (5-HIAA), respectively, but also possesses outstanding sensing characteristics in terms of fast response, high sensitivity, and specific selectivity. Zn-MOF 1 performs as efficient sensing of carcinoid biomarkers to provide a fresh detection platform for the diagnosis of carcinoids. In addition, the sensing mechanism was also explored on the basis of ultraviolet-visible (UV-vis) absorption, DFT calculations, and structural analysis.

Intra-platelet serotonin and YAP contributed to poor prognosis of hepatocellular carcinoma.

AIMS: Intra-platelet 5-HT (IP 5-HT) and YAP exhibit an important role in hepatocellular carcinoma (HCC). The aim of the study was to investigate whether IP 5-HT and YAP could affect the progression and prognosis of HCC. METHODS: 5-HT level and YAP expression were measured and were compared between HCC patients and control patients. By grouping HCC patients, we analyzed clinical indicators and survival. The predictive nomogram was established by R software according to the risk factors obtained from multivariate analysis. RESULTS: Higher IP 5-HT level and higher YAP expression were associated with poorer prognosis. In addition, they were also associated with BCLC stages. Higher IP 5-HT was found to be related with higher international normalized ratio (INR) (p = 0.040), more death (p = 0.015) and higher YAP expression (p < 0.001). Similarly, higher YAP expression was proved to be associated with lower platelet counts (PLT) (p = 0.032), smaller tumor size (p = 0.017), more death (p < 0.001) and higher IP 5-HT (p < 0.001). In addition, alkaline phosphatase (ALP), YAP and tumor size were proved to be independent risk factors. By using risk factors, we have established a prognostic prediction nomogram for HCC patients. In the prognostic prediction nomogram, patients with higher scores would have poorer prognosis. CONCLUSIONS: IP 5-HT and YAP might affect the progression and prognosis of HCC through synergistic effect. Moreover, IP 5-HT might affect HCC by regulating YAP expression. Thus, both of them might be potential therapeutic targets. By establishing the prognostic prediction nomogram, we could improve the prediction system.

Convenient ultrasonic preparation of a water stable cluster-based Cadmium(II) coordination material and highly sensitive fluorescent sensing for biomarkers DPA and 5-HT.

In recent years, a new type of micro-porous material, namely metal organic framework material, has received more and more attention from many basic and industrial fields because these materials possess unique advantages. In this work, through the powerful sonochemical preparation method, a three-dimensional cluster-based CdII-MOFs, {[Cd(abtz)2(H2O)2]·(ClO4)2·H2O}n (1, abtz = 1-(4-aminobenzyl)-1H-1,2,4-triazole) can be quickly synthesized in the facile ultrasonic method. Powder X-ray diffraction (PXRD) measurement confirms that these bulky samples 1 (synthesized on different ultrasonic powers and ultrasonic time conditions) were pure. In addition, ultrasonic chemical time and irradiation power did not change the structure of composites materials 1. SEM and morphological changes of 1 in the ultrasonic synthesis are also determined. Moreover, 1 exhibits good stability, the structure of 1 can be maintained not just in various solvents, and in aqueous environments with pH values from 2 to 12. Photo-luminescent experiment also reveals that complex 1 has the excellent application prospect as highly sensitive sensing material for the biomarker DPA (2,6-pyridine dicarboxylic acid) and 5-HT (5-hydroxytryptamine) through the photo-luminescence "turn-on" and "turn-off" effect, respectively. Further photo-luminescent measurements also show that different ultrasonic powers and ultrasonic time can effectively induce fluorescent sensing enhancement for biomarkers DPA and 5-HT based on the water stable clustered-based cadmium(II) coordination framework.

Effects of testosterone replacement on serotonin levels in the prostate and plasma in a murine model of hypogonadism.

Benign prostate hyperplasia is a dysfunctional disease with an elevated prevalence. Despite the accepted impact of aging and testosterone (TES) in its pathophysiology, its aetiology remains unknown. Recent studies described that serotonin (5-HT) inhibits benign prostate growth through the modulation of the androgen receptor, in the presence of TES. Accordingly, this work aimed to determine the impact of castration and TES replacement in plasmatic and prostatic 5-HT regulation. C57BL/6 mice were submitted to surgical castration and divided into three groups, continually exposed to either vehicle or different TES doses for 14 days. Plasmatic 5-HT concentration was measured before and after castration, and after TES reintroduction. Finally, total prostatic weight and intra-prostatic 5-HT were determined in the different groups. Our results demonstrate that mice prostate exhibits high 5-HT tissue levels and that intra-prostatic total 5-HT was independent of castration or TES reintroduction, in all studied groups. Also, 5-HT plasmatic concentration significantly increased after castration and then normalized after TES administration. Our findings revealed that mice prostate has a high 5-HT content and that total prostatic 5-HT levels do not depend on androgens' action. On the other hand, castration induced a significant increase in plasmatic 5-HT concentration, raising the hypothesis that androgens might be regulating the production of extra-prostatic 5-HT.

Creatine and taurine mixtures alleviate depressive-like behaviour in Drosophila melanogaster and mice via regulating Akt and ERK/BDNF pathways.

We investigated the antidepressant effect of creatine (CRE) and taurine (TAU) mixtures on behavioural changes and biomarkers in stress-induced depression in Drosophila melanogaster and a mouse model. Following CRE/TAU mixture administration in the Drosophila model, depression-like state induced by vibration, locomotion, climbing activity, and survival rate were measured. The normal stress (NS) group demonstrated decreased movement than the control (CON) group; movements in the CRE/TAU-treated group (particularly 0.15/0.5%) returned to the CON levels. Antidepressant effects of CRE/TAU mixtures were confirmed in a depressive mouse model induced by chronic mild stress. In behavioural assessments, movement and sucrose preference of the CRE/TAU group increased to a similar level as in the positive control group; hippocampal catecholamine and serotonin levels increased significantly. Stress-related hormones (adrenocorticotropic and corticotropin-releasing hormones) and inflammatory factors (IL-1ß, IL-6, and TNF-α) increased in the NS group but significantly decreased in the CRE/TAU-treated group. Brain signalling protein expression ratio of phosphorylated protein kinase B (p-Akt)/Akt, phosphorylated extracellular signal-regulated kinase (p-ERK)/ERK, and brain-derived neurotrophic factor (BDNF) significantly increased in the CRE/TAU-treated group. These results indicate that CRE/TAU-induced antidepressant effects are associated with increased behavioural patterns and downregulation of stress hormones and cytokines, mediated through Akt and ERK/BDNF pathways in vertebrate models.

Hypothermia induced by central injection of sucralose potentially occurs via monoaminergic pathways in the hypothalamus of chicks.

Oral administration of sucralose has been reported to stimulate food intake through inducing hypothalamic neuropeptide Y (NPY) in mice and fruit flies. However, the underlying mechanisms of action of sucralose in hypothermia and NPY and monoamine regulation remain unknown. The aim of the present study was to investigate central effects of sucralose on body temperature, NPY, and monoamine regulation, as well as its peripheral effects, in chicks. In Experiment 1, 5-day-old chicks were centrally injected with 1 µmol of sucralose, other sweeteners (erythritol and glucose), or saline. In Experiment 2, chicks were centrally injected with 0.2, 0.4, and 1.6 µmol of sucralose or saline. In Experiment 3, chicks were centrally injected with 0.8 µmol of sucralose or saline, with a co-injection of 100 µg fusaric acid (FA), an inhibitor of dopamine-ß-hydroxylase, to examine the role dopamine in sucralose induced hypothermia. In Experiment 4, 7-16-day-old chicks were orally administered with 75, 150, and 300 mg/2 ml distilled water or sucralose, daily. We observed that the central injection of sucralose, but not other sweeteners, decreased body temperature (P < .05) in chicks; however, the oral injection did not influence body temperature, food intake, and body weight gain. Central sucralose administration decreased dopamine and serotonin and stimulated dopamine turnover rate in the hypothalamus significantly (P < .05). Notably, sucralose co-injection with FA impeded sucralose-induced hypothermia. Sucralose decreases body temperature potentially via central monoaminergic pathways in the hypothalamus.

True Picomolar Neurotransmitter Sensor Based on Open-Ended Carbon Nanotubes.

Neurotransmitters are important chemicals in human physiological systems for initiating neuronal signaling pathways and in various critical health illnesses. However, concentration of neurotransmitters in the human body is very low (nM or pM level) and it is extremely difficult to detect the fluctuation of their concentrations in patients using existing electrochemical biosensors. In this work, we report the performance of highly densified carbon nanotubes fiber (HD-CNTf) cross-sections called rods (diameter ∼ 69 µm, and length ∼ 40 µm) as an ultrasensitive platform for detection of common neurotransmitters. HD-CNTf rods microelectrodes have open-ended CNTs exposed at the interface with electrolytes and cells and display a low impedance value, i.e., 1050 Ω. Their fabrication starts with dry spun CNT fibers that are encapsulated in an insulating polymer to preserve their structure and alignment. Arrays of HD-CNTf rods microelectrodes were applied to detect neurotransmitters, i.e., dopamine (DA), serotonin (5-HT), epinephrine (Epn), and norepinephrine (Norepn), using square wave voltammetry (SWV) and cyclic voltammetry (CV). They demonstrate good linearity in a broad linear range (1 nM to 100 µM) with an excellent limit of detection, i.e., 32 pM, 31 pM, 64 pM, and 9 pM for DA, 5-HT, Epn, and Norepn, respectively. To demonstrate practical application of HD-CNTf rod arrays, detection of DA in human biological fluids and real time monitoring of DA release from living pheochromocytoma (PC12) cells were performed.

Effect of Sleeve Gastrectomy on Bone Metabolism and Serum 5-Hydroxytryptamine in Obese Rats.

BACKGROUND Studies have shown that bariatric surgery, such as sleeve gastrectomy (SG), has an adverse effect on bone, including decreased bone mineral density (BMD) and bone metabolism. Peripheral 5-hydroxytryptamine (5-HT) has an adverse regulatory effect on bone formation. Here, we assessed changes in bone metabolism and whether 5-HT is involved in the effect of SG on bone metabolism. MATERIAL AND METHODS A rat model of obesity was established using Wistar rats. After successful modeling, rats were randomly assigned to 2 groups - the SG group and the Sham group - with 10 rats in each group. We then performed sleeve gastrectomy or sham operation. Bone metabolic markers and BMD of rats were measured at 2 and 16 weeks after the operation and the level of 5-HT in serum was determined. Rats were killed at 16 weeks after the operation, and bones of the hind limbs were harvested to measure 5-HT by immunofluorescence. RESULTS BMD was decreased and bone metabolism demonstrated a trend of bone destruction in the rats after SG. A significantly increasing trend in the level of serum 5-HT was found, and bone immunofluorescence showed increased expression of 5-HT. CONCLUSIONS BMD was decrease and bone metabolism demonstrated a trend of bone destruction after SG. SG can affect the level of 5-HT in serum or bone tissue and the 5-HT may be involved in the process through which SG affects bone metabolism.

Effects of Kudoa septempunctata infections in a human intestinal epithelial model (Caco-2): a DNA microarray study.

Kudoa septempunctata, a myxosporean parasite infecting the trunk muscles of olive flounder (Paralichthys olivaceus), is reported to cause food poisoning in humans. The molecular mechanisms underlying the toxicity of K. septempunctata spores remain largely unknown. In the present study, we examine the molecular basis of such toxicity using DNA microarray analysis of K. septempunctata-inoculated human colon adenocarcinoma cells (Caco-2). We observed that the transepithelial resistance of the K. septempunctata-inoculated Caco-2 cell monolayers decreased markedly. DNA microarray analysis revealed that the mRNA expression profiles of control and inoculated cells clearly differed. Inflammatory and bacteria-related pathways, such as interleukin-8 (IL-8) production and MAPK/NF-kappa B pathway, were enriched. The concentrations of IL-8 and serotonin (5-HT) were higher in inoculated cells than in controls. K. septempunctata invasion damages the human intestinal epithelium, causing increased production of IL-8 and 5-HT, which likely results in the vomiting associated with K. septempunctata invasion.Abbreviations: AP-1: activator protein 1; DAVID: Database for Annotation, Visualization and Integrated Discovery; ENS: enteric nervous system; FARMS: Factor Analysis for Robust Microarray Summarization; FDR: false discovery rate; GO: Gene Ontology; 5-HT: 5-hydroxytryptamine; IL-8: Interleukin-8; KEGG: Kyoto Encyclopedia of Genes and Genomes; K. septempunctata: Kudoa septempunctata; NF-kappa B: nuclear factor-kappa B; TJ: tight junction; TER: transepithelial electrical resistance.

Protective effect of curcumin nanoparticles against cardiotoxicity induced by doxorubicin in rat.

The present study designed to investigate the protective effect of curcumin nanoparticles (CUR-NPs) on the cardiotoxicity induced by doxorubicin. Rats were divided into four groups; control, rats treated daily with CUR-NPs (50 mg/kg) for 14 days, rats treated with an acute dose of doxorubicin (20 mg/kg) and rats treated daily with CUR-NPs for 14 days injected with doxorubicin on the 10th day. After electrocardiogram (ECG) recording from rats at different groups, rat decapitation was carried out and the heart of each rat was excised out to measure the oxidative stress parameters; lipid peroxidation (MDA), nitric oxide (NO) and reduced glutathione (GSH) and the activities of Na,K,ATPase and acetylcholinesterase (AchE). In addition, the levels of dopamine (DA), norepinephrine (NE) and serotonin (5-HT) were determined in the cardiac tissues. Lactate dehydrogenase (LDH) activity was measured in the serum. The ECG recordings indicated that daily pretreatment with CUR- NPs has prevented the tachycardia (i.e. increase in heart rate) and ameliorated the changes in ST wave and QRS complex induced by doxorubicin. In addition, CUR-NPs prevented doxorubicin induced significant increase in MDA, NO, DA, AchE and LDH and doxorubicin induced significant decrease in GSH, NE, 5-HT and Na,K,ATPase. According to the present findings, it could be concluded that CUR-NPs have a protective effect against cardiotoxicity induced by doxorubicin. This may shed more light on the importance of CUR-NPs pretreatment before the application of doxorubicin therapy.

Spatial Mapping of Cellular Metabolites Using DESI Ion Mobility Mass Spectrometry.

Spatial mapping of cellular metabolites, such as neurotransmitters and lipids, on the tissue, can increase our understanding of the biological functions of those molecules. Mass spectrometry imaging (MSI) techniques, such as desorption electrospray ionization (DESI), have not demonstrated the ability to perform metabolite analysis at mammalian single cell level yet. However, they can be a valuable tool to provide insight into cellular metabolism in a very small population (tens) of cells. DESI MSI, coupled with ion mobility separation, improves the peak capacity and signal-to-noise ratio of detected analytes by separating a molecule of interest from interfering isobaric species found in a complex biological matrix. Here we present a protocol for mapping cellular metabolites neurotransmitters, such as serotonin, adenosine, and glutamine directly in brain tissue samples using DESI MSI.

Highly sensitive and selective electrochemical paper-based device using a graphite screen-printed electrode modified with molecularly imprinted polymers coated Fe3O4@Au@SiO2 for serotonin determination.

Herein, we propose a highly sensitive and selective three-dimensional electrochemical paper-based analytical device (3D-ePAD) to determine serotonin (Ser). It uses a graphite-paste electrode modified with nanoparticles coated with molecularly imprinted polymer (MIP). Fe3O4@Au nanoparticles were encapsulated with silica to create novel nano-sized MIP. Morphology and structural characterization reveal that silica imprinted sites (Fe3O4@Au@SiO2) synthesized via sol-gel methods provide excellent features for Ser detection, including high porosity, and greatly improve analyte diffusion and adsorption to provide a faster response by the MIP sensor. The template molecule was effectively removed by solvent extraction to provide a greater number of specific cavities that enhance analyte capacity and sensitivity. The 3D-ePAD was fabricated by alkyl ketene dimer (AKD)-inkjet printing of a circular hydrophobic detection zone on filter paper for application of aqueous samples, coupled with screen-printed electrodes on the paper, which was folded underneath the hydrophobic zone. The sensor was constructed by drop coating of Fe3O4@Au@SiO2-MIP nanocomposites on the graphite electrode (GPE) surface. The MIP sensor (Fe3O4@Au@SiO2-MIP/GPE) was used in the detection of Ser by linear-sweep voltammetry (LSV) in 0.1 M phosphate buffer at pH 8.0. The device exhibits high sensitivity toward Ser, which we attribute to synergistic effects between catalytic properties, electrical conductivity of Fe3O4@Au@SiO2, and significantly increased numbers of imprinted sites. Ser oxidation was observed at +0.39 V. Anodic peak currents for Ser show linearity from 0.01 to 1000 µM (y = 0.0075 ± 0.0049 x + 0.4071 ± 0.0052, r2 = 0.993), with a detection limit of 0.002 µM (3S/N). The device provides good repeatability (%relative standard deviations; RSD) = 4.23%, calculated from the current responses of ten different MIP sensors). The device also exhibits high selectivity and reproducibility (%RSD = 8.35%, obtained from five calibration plots). The analytical performance of the device is suitable for the determination of Ser in pharmaceutical capsules and urine samples.