The effect of acid use as a preservative on the results of biochemical tests measured in 24-h urine.

Twenty-four-hour urine measurements play a crucial role in the diagnosis, follow-up and treatment of various diseases. There are different approaches to the collection of urine in patients who need to collect multiple urine samples at a time, especially in hospitals with heavy workloads. In this study, we compared the sodium, potassium, chloride, amylase, calcium, creatinine, phosphorus, microalbumin, protein, magnesium, urea, uric acid, adrenaline, noradrenaline, dopamine, metanephrine, normetanephrine, vanillylmandelic acid, 5-hydroxyindoleacetic acid and homovanillic acid results of 24-h urine samples analyzed immediately without acid addition, which we accepted as the reference and baseline measurement, with the results of the samples analyzed after waiting for 24 h without acid addition, analyzed immediately with acid addition and analyzed after waiting for 24 h with acid addition. Chloride, microalbumin, amylase and protein tests, which are recommended to be measured in the sample without preservatives, are affected by acid addition. Adrenaline, noradrenaline and dopamine, which are the tests recommended to be measured in acid-added urine are degraded in the samples without acid, and the levels of metanephrine and normetanephrine were not significantly degraded in the absence of preservatives.

Psychosocial stress and neuroendocrine biomarker concentrations among women living with or without HIV.

OBJECTIVE: Women living with HIV (WLWH) experience psychosocial stress related to social-structural vulnerabilities. To investigate neuroendocrine pathways linking stress and increased cardiovascular disease risk among WLWH, we evaluated associations between psychosocial stress (i.e., perceived stress, posttraumatic stress, and experiences of race- and gender-based harassment) and a composite neuroendocrine biomarker index among WLWH and women without HIV. METHODS: In 2019-2020, Women's Interagency HIV Study participants in Washington, DC completed a questionnaire and provided blood and 12-hour overnight urine samples for testing of serum dehydroepiandrosterone sulfate (DHEA-S) and urinary free cortisol, epinephrine, and norepinephrine. Psychosocial stress was measured using the Perceived Stress Scale, PTSD Checklist-Civilian Version, and Racialized Sexual Harassment Scale. Latent profile analysis was used to classify participants into low (38%), moderate (44%), and high (18%) stress groups. Composite biomarker index scores between 0-4 were assigned based on participants' number of neuroendocrine biomarkers in high-risk quartiles (≥75th percentile for cortisol, epinephrine, and norepinephrine and ≤25th percentile for DHEA-S). We evaluated associations between latent profile and composite biomarker index values using multivariable linear regression, adjusting for socio-demographic, behavioral, metabolic, and HIV-related factors. RESULTS: Among 90 women, 62% were WLWH, 53% were non-Hispanic Black, and median age was 55 years. In full multivariable models, there was no statistically significant association between psychosocial stress and composite biomarker index values among all women independent of HIV status. High (vs. low) psychosocial stress was positively associated with higher mean composite biomarker index values among all monoracial Black women (adjusted ß = 1.32; 95% CI: 0.20-2.43), Black WLWH (adjusted ß = 1.93; 95% CI: 0.02-3.83) and Black HIV-negative women (adjusted ß = 2.54; 95% CI: 0.41-4.67). CONCLUSIONS: Despite a null association in the overall sample, greater psychosocial stress was positively associated with higher neuroendocrine biomarker concentrations among Black women, highlighting a plausible mechanism by which psychosocial stress could contribute to cardiovascular disease risk.

Urinary Stress Hormones, Hypertension, and Cardiovascular Events: The Multi-Ethnic Study of Atherosclerosis.

[Figure: see text].

Effect of Exhaustive Training or Forced Immobilization on Physiological Condition and Main Metabolic and Stress Markers of Wistar Male Rats.

For correct and reliable experimental in vivo assessment of antistress effect of various bioactive substances, appropriate biomodels reproducing stress and organism response to stress in laboratory animals should be chosen. We chose treadmill test for simulating exhaustive physical load and forced immobilization accompanied by disorders of physiological and psychological condition. Verification of the models used indicates their wide applicability for testing certain biological manifestations under reproduced stress exposure.

Massive ß1-Adrenergic Receptor Reaction Explains Irreversible Acute Arrhythmia in a Fatal Case of Acute Pure Caffeine Intoxication.

Caffeine, a naturally occurring purine-based alkaloid, is the most consumed psychostimulant worldwide. Since caffeine pharmacokinetics shows extreme interindividual variability, it is not easy to establish its toxic dose. Only a few cases of death due to acute caffeine intoxication have been described so far, the majority of which attributable to massive assumption of caffeine-based medications. We present a case of acute caffeine overdose due to ingestion of pure caffeine. The extremely high blood concentration of caffeine determined a strong cardiovascular response, leading to fatal arrhythmia, as supported by histological evidence of myocardial injury. Quantitation of catecholamines and their metabolites in urine samples was performed and showed level near the highest limit of normal ranges for norepinephrine and high level of epinephrine. Contraction band is a pathological modification of the myocell caused by the catecholaminergic action and can occur in conditions of alteration due to the interaction between calcium and catecholamines. We demonstrated the ß1-adrenoceptor involvement in our fatal case by immunohistochemical analysis.

Differential Responses of Urinary Epinephrine and Norepinephrine to 24-h Shift-Work Stressor in Physicians.

Multiple stressors, including 24-h-shifts characterise the working environment of physicians, influencing well-being, health and performance. We aimed to evaluate the effect of the stressor 24-h-shift on the adrenal medullary and sympathoneural system in physicians with the hypothesis that shift work might have different impacts on both systems. Twenty-two physicians collected two 12-h-urine samples ("daytime" and "nighttime") during a 24-h shift ("on-duty") and on a free weekend ("off-duty"), respectively. Urinary excretion rates per m2 body surface area were assessed for the catecholamines epinephrine, norepinephrine and their respective free O-methylated metabolites metanephrine and normetanephrine by LC-MS/MS-analysis. The stressor provoked differential responses of epinephrine and norepinephrine. Epinephrine excretion rates showed significant increases from off to on duty. The largest proportional change (off-duty to on-duty) for epinephrine was observed for nighttime (205%), the increase for daytime was 84%. An increase in norepinephrine from off to on duty was only visible for nighttime collections. For the catecholamine metabolites, normetanephrine paralleled norepinephrine and exhibited an increase in excretion from off to on duty during nighttime collections of 53% whereas there was no change during daytime collections (3%). In conclusion: Whilst the 24-h-shift-work stressor in physicians activates the sympatho-adrenomedullary system, represented by epinephrine, the sympathoneural response through norepinephrine reflects mainly an ambulatory position during working hours.

Parasympathetic and sympathetic nervous systems interactively predict change in cognitive functioning in midlife adults.

The two branches of the autonomic nervous system (ANS) have been individually linked to changes in cognitive functioning: The parasympathetic nervous system (PNS) has been associated with healthy cognitive aging, whereas excessive sympathetic nervous system (SNS) activity has been linked to heightened cognitive decline. Despite these separate findings and despite the integrative nature of the ANS, little work has examined the two branches simultaneously to better understand their interactive effects on changes in cognitive functioning in midlife adults. We examined cognitive change in two waves of the Midlife in the United States (MIDUS) study cognitive project and indexed PNS and SNS activity from heart rate variability and epinephrine levels, respectively, from the MIDUS biomarker project (minimum n = 843, 57.9% female, mean age at first wave = 53.8 years). Our findings indicate that greater PNS responsivity (i.e., greater withdrawal and greater recovery) in response to cognitive challenge is associated with attenuated cognitive decline, but only among individuals with low SNS levels; at higher SNS levels, the effects of the PNS on cognitive decline are attenuated. These results suggest that future research targeting the ANS and cognitive aging should consider both ANS branch's effects simultaneously.

Experiences of Discrimination and Urinary Catecholamine Concentrations: Longitudinal Associations in a College Student Sample.

BACKGROUND: Experiences of discrimination are a risk factor for subsequent cardiovascular disease. However, there is a lack of longitudinal research examining associations between discrimination and urinary catecholamines. This is surprising given the likely mediating role of sympathetic nervous system dysregulation in the association between psychosocial stress and cardiovascular morbidity. PURPOSE: The current study examined the 3 year longitudinal association between experiences of discrimination and urinary catecholamines. METHODS: The sample included 149 college students (mean age at baseline = 18.8, standard deviation = 0.96; 45% Black/African American; 55% White/European American). Concentrations of epinephrine and norepinephrine-urinary catecholamines with established links to psychosocial stress exposure and subsequent morbidity-were determined from 12 hr overnight samples. RESULTS: Results indicated that experiences of discrimination were associated with increases in both epinephrine (ß = .284, standard error [SE] = .117, p = .015) and norepinephrine (ß = .306, SE = .114, p = .001). These longitudinal associations persisted after adjusting for negative affect, depression, and rejection sensitivity and did not vary as a function of race/ethnicity. CONCLUSIONS: Results suggest that examination of overnight urinary catecholamines as a biological mediator of associations between experiences of discrimination and cardiovascular morbidity is warranted.

Screen-printed disposable electrodes using graphite-polyurethane composites modified with magnetite and chitosan-coated magnetite nanoparticles for voltammetric epinephrine sensing: a comparative study.

Disposable screen-printed electrodes based on the use of graphite-polyurethane composites modified with magnetite nanoparticles (MNP-SPE) or chitosan-coated magnetite nanoparticles (CHMNP-SPE) are described. The MNP and CHMNP were synthetized and comparatively characterized by TEM, XRD, FTIR, and TGA/DTG. The MNP-SPE and CHMNP-SPE were characterized by SEM and EDX. After optimization of the MNP percentage in MNP-SPE, the materials were electrochemically characterized by cyclic voltammetry, EIS, and chronocoulometry. The electrodes were tested for their performance towards sensing of epinephrine (EP). The CHMNP-SPE is found to have better electrochemical responses in comparison to the MNP-SPE. This is assumed to be due to the chitosan coating which also protects the MNPs from oxidation under air and at different applied potential fields. The performances of the MNP-SPE and CHMNP-SPE were studied by DPV after optimization of equilibration time and DPV parameters. Response is linear in the 0.1-0.8 µM EP concentration range, at 0.03 V (vs. pseudo-Ag/AgCl), and the detection limit is 25 nM for the MNP-SPE. The linear response for the CHMNP-SPE was 0.1-0.6 µM, at 0.0 V (vs. pseudo-Ag/AgCl), and a LOD of 14 nM was achieved. The devices were used for the quantification of EP in synthetic urine and in cerebrospinal synthetic fluids. Recoveries from spiked samples are in the 95.6-102.2% range for the CHMNP-SPE and in the 98.3-109% range for MNP-SPE. The stability of the respective sensors was investigated and compared over a period of 5 months. The EP peak currents were found to decrease by only 4% for the CHMNP-SPE, while the MNP-SPE lost 23% of its EP peak current. Accordingly, the CHMNP-SPE was chosen as the most stable and sensitive sensor for EP. Graphical abstract Schematic figure of modification of a graphite-polyurethane screen-printed composite electrode with magnetite nanoparticles (MNPs) and chitosan-coated magnetite nanoparticles (CHMNPs) for the voltammetric determination of epinephrine (EP). Improved response of CHMNP-SPE (black voltammogram) in comparison to MNP-SPE (red voltammogram) was attributed to the protection of MNP from oxidation.

Boronic acid-modified polyhedral oligomeric silsesquioxanes on polydopamine-coated magnetized graphene oxide for selective and high-capacity extraction of the catecholamines epinephrine, dopamine and isoprenaline.

Amino-functionalized polyhedral oligomeric silsesquioxanes (POSS-8NH2) were covalently bound to the surface of polydopamine-coated magnetized graphene oxide. It was then reacted with 4-formylphenylboronic acid to prepare a "cubic boronic acid"-bonded magnetic graphene oxide adsorbent. The new adsorbent exhibits better selectivity and much higher adsorption capacity for ortho-phenols over adsorbents where small boronic ligands are directly bound to the surface of the material. It is shown to enable selective and faster enrichment of the catecholamines epinephrine (EP), dopamine (DA) and isoprenaline (IP) with high selectivity over many potential interferents that can occur in urine. The analytes were then quantified by HPLC with fluorometric detection. Under optimal conditions, response is linear (R2 ≥ 0.9907), limits of detection are low (0.54-2.3 ng·mL-1), and reproducibility is acceptable (inter- and intra-day assay RSDs of≤10.9%). The method was successfully applied to the determination of endogenous EP and DA and exogenous IP in urine samples. Graphical abstractSchematic of boronic acid (BA)-modified polyhedral oligomeric silsesquioxanes (POSS) on polydopamine-coated magnetized graphene oxide (magGO). The material (magGO@POSS-BA) has good selectivity and higher adsorption capacity to ortho-phenols and can be applied to enrich the catecholamines in urine.

Identification of Catecholamine Neurotransmitters Using a Fluorescent Electronic Tongue.

Catecholamine neurotransmitters, specifically, dopamine (DA), epinephrine (EP), and norepinephrine (NE), are known as substantial indicators of various neurological diseases. Developing rapid detection methods capable of simultaneously screening their concentrations is highly desired for early clinical diagnosis of such diseases. To this aim, we have designed an optical sensor array using three fluorescent dyes with distinct emission bands and have monitored variations in their emission profiles upon the addition of DA, EP, and NE in the presence of gold ions. Because of the different reducing power of catecholamines, differently sized gold nanoparticles (GNPs) with different levels of aggregation were generated, resulting in different amounts of spectral overlap between the absorption band of the in situ generated plasmonic GNPs and the emission bands of the fluorescent dyes. These energy-transfer-based fingerprint profiles were used to discriminate the neurotransmitters by applying pattern recognition methods including linear discriminant analysis (LDA) and artificial neural networks (ANN) and to determine their concentration using multiple linear regression (MLR). Our proposed array also showed a good performance in the discrimination of DA, EP, and NE in complex biological media such as human urine.

A molybdenum disulfide quantum dots-based ratiometric fluorescence strategy for sensitive detection of epinephrine and ascorbic acid.

In this paper, a novel and sensitive ratiometric fluorescence strategy for the detection of epinephrine (EP) and ascorbic acid (AA) was established based on the fluorescence resonance energy transfer (FRET) between the molybdenum disulfide quantum dots (MQDs) and the fluorescent oxidative polymerization product (PEP-PEI) of EP in polyethyleneimine (PEI) aqueous solution. The continuous formation of PEP-PEI can lead to the fluorescence quenching of MQDs at 414 nm while the fluorescence of PEP-PEI at 522 nm gradually increased. The introduction of AA can inhibit the oxidative polymerization process of EP due to the strong reducibility of AA, resulting in the fluorescence recovery of MQDs at 414 nm and the fluorescence decreasing of PEP-PEI at 522 nm. Therefore, EP and AA can be monitored by measuring the ratio of the fluorescence intensities at 522 nm and 414 nm. A good linear calibration of I522/I414 versus EP and AA concentrations were obtained within 0.2-40 µM and 0.5-40 µM, respectively. And the detection limit was 0.05 µM for EP and 0.2 µM for AA. Furthermore, the developed ratiometric fluorescence method with high sensitivity and selectivity was applied for EP in human urine samples and AA in human serum samples determination with satisfactory results obtained.

[Pharmacological Effects of Yokukansankachimpihange on Urinary Catecholamine in Restraint-stressed Mice].

Herbal medicines, acupuncture and moxibustion are often used for unidentified complaints. It is well known that catecholamine secreted by the sympatho-adrenal medullary system primarily functions to increase cardiac output and raise glucose levels in the blood during acute stress. In the present study, the effects of yokukansankachimpihange (YKSKCH, a Kampo medicine) on urinary catecholamine in mice that were repeatedly stressed by restraining were examined. Restraint stress (240 min/d×3 d×3 cycles, daytime: 12:00-16:00) induced a marked increase in noradrenaline (NA) and adrenaline (A) levels in the urine. Oral administration of YKSKCH (750 mg/kg of body weight) significantly inhibited the increase in urinary NA and A levels in mice after repeated restraint stress. In addition, the NA/dopamine (physical stress) and A/dopamine (mental stress) ratios were lower in the 750 mg/kg YKSKCH-treated group than in the control group. The tail suspension test was also performed and locomotor activity was investigated. Oral administration of YKSKCH at 750 mg/kg significantly reduced the immobility time, which was longer in mice after repeated restraint stress. Furthermore, oral administration of YKSKCH at 750 mg/kg increased locomotor activity, which was lower in mice after repeated restraint stress. These results suggest that YKSKCH has positive effects on mental and physical stress after repeated restraint stress, without reducing locomotor activity.

Preparation of Molecularly Imprinted Magnetic Graphene Oxide-Gold Nanocomposite and Its Application to the Design of Electrochemical Sensor for Determination of Epinephrine.

In this study, a new molecularly imprinted polymer (MIP) based nanocomposite was synthesized then used to determine epinephrine (EPN) by the use of an electrochemical sensor modified by it. Typical techniques for the synthesis of MIP have disadvantages, such as weak binding sites, low mass transfer and low selectivity. One of the ways to improve electrochemical properties is the use of graphene oxide (GR-Ox) and modification of its surface. For this purpose, GR-Ox was initially magnetized (MGR-Ox), then its surface was coated with a silica layer, and gold nanoparticles (AuNPs) were coated on its surface. Subsequently, copolymerization of methacrylic acid (MAA) and N,N'-methylene-bis-acrylamide (MBA) in the presence of EPN was performed on the MGO-AuNPs surface. Afterwards, a selective carbon paste electrode (CPE) with synthetic nanocomposite was fabricated to detect EPN. Under optimal conditions, a linear range from 10-8 to 5.0 × 10-7 M was obtained for the measurement of EPN in urine and blood with a detection limit of 5 × 10-9 M (S/N = 3).

The Association between Long-Term Air Pollution and Urinary Catecholamines: Evidence from the Multi-Ethnic Study of Atherosclerosis.

BACKGROUND: Autonomic nervous system effects have been hypothesized as a mechanism of air pollutant health effects, though scant prior epidemiologic research has examined the association between air pollutants and catecholamines. OBJECTIVES: To examine the association of long-term air pollutants with three urinary catecholamines: dopamine (DA), epinephrine (EPI), and norepinephrine (NE). As a secondary aim, we also examined the association between short-term (or acute) exposure to fine particulate matter [particulate matter with aerodynamic diameter [Formula: see text] ([Formula: see text])] and those catecholamines. METHODS: We used data from the Multi-Ethnic Study of Atherosclerosis (MESA) and two of its ancillary studies, the MESA Air Pollution Study and the MESA Stress Study, to provide exposure and outcome data. DA, EPI, and NE from urine samples were collected from 2004 to 2006 from 1,002 participants in the New York, New York, and Los Angeles, California, study sites. Spatiotemporal models incorporated cohort-specific monitoring and estimated annual average pollutant concentrations ([Formula: see text], [Formula: see text], [Formula: see text] and black carbon) at participants' homes the year prior to urine collection. Secondarily, short-term [Formula: see text] was evaluated (day of, day prior, and 2- to 5-d lags prior to urine collection). Several covariates were considered confounders (age, race, sex, site, socioeconomic status, cardiovascular disease risk factors, psychosocial stressors, and medication use) in linear regression models. RESULTS: A [Formula: see text] higher annual [Formula: see text] concentration was associated with 6.3% higher mean EPI level [95% confidence interval (CI): 0.3%, 12.6%]. A 2-[Formula: see text] higher annual ambient [Formula: see text] concentration was associated with 9.1% higher mean EPI (95% CI: 3.2%, 15.3%) and 4.4% higher DA level (95% CI: 1%, 7.9%). [Formula: see text], black carbon, and short-term [Formula: see text] exposures were not significantly associated with any of the catecholamines. CONCLUSIONS: We found an association between EPI and long-term concentrations of [Formula: see text] and [Formula: see text] and an association between DA and long-term ambient [Formula: see text]. These novel findings provide modest support for the hypothesis that air pollutant exposures are related to sympathetic nervous system activation. https://doi.org/10.1289/EHP3286.

Electrochemical simultaneous analysis of dopamine and epinephrine using double imprinted One MoNomer acryloylated graphene oxide-carbon black composite polymer.

A novel One MoNomer dual imprinted graphene oxide/carbon black composite polymer was developed applying 'surface-grafting from' approach on the screen printed carbon electrode for the electrochemical sensing of dopamine and epinephrine. Acryloylated-graphene oxide/carbon black was synthesized for the first time. This served both as a crosslinker and monomer leading to the fast electron transfer from the redox centre to the electrode. The oxidation peak potentials of both the targets were found separated by 200 mV which enabled their simultaneous analysis in real world samples, without any cross reactivity, interferences, and false-positives. The detection limits realized by the proposed sensor, under optimized analytical conditions, were found to be as low as 0.028, 0.028,0.061 and 0.029 ng mL-1 for dopamine and 0.017, 0.018, 0.019 and 0.020 ng mL-1 for epinephrine (S/N = 3) in aqueous, blood serum, urine and pharmaceutical samples. Such sensor could be considered suitable for the primitive diagnosis of several chronic diseases, manifested at ultra-trace level.

Core body temperature, energy expenditure, and epinephrine during fasting, eucaloric feeding, and overfeeding in healthy adult men: evidence for a ceiling effect for human thermogenic response to diet.

BACKGROUND: In homeothermic animals, approximately 50% of daily energy expenditure (EE) is spent to maintain a consistent core body temperature (CBT). In humans, little is known about CBT responses to feeding and overfeeding and their relationship to diet-related changes in EE. OBJECTIVE: To study the effects of feeding and overfeeding on CBT and its association with diet-induced thermogenesis (DIT). DESIGN: Fifty-three healthy men with normal glucose regulation and a wide range of body composition (mean ±â€¯SD, body fat: 25 ±â€¯8%, range: 7-43%) had 24-h EE assessed during fasting in a whole-room indirect calorimeter with concomitant CBT measurement by ingestible capsules and 24-h urinary collection for catecholamine measurements. Changes in 24-h EE (DIT) and CBT compared to fasting were assessed during three normal-protein (20%) diets using a cross-over design: one eucaloric diet (EBL, 50% carbohydrate, n = 37) and two overfeeding diets with 200% energy requirements: a high-fat (FNP, 60% fat, n = 25) and a high-carbohydrate (CNP; 75% carbohydrate, n = 24) diet. RESULTS: The average 24-h CBT (avgCBT) during fasting was 36.81 ±â€¯0.14 °C (inter-individual CV = 0.4%) and positively correlated with 24-h urinary epinephrine (r = 0.61, p < 0.001), but not with body composition measures (p > 0.05). AvgCBT increased during EBL (Δ = 0.06 ±â€¯0.11 °C, p = 0.002), FNP (Δ = 0.13 ±â€¯0.14 °C, p < 0.001), and CNP (Δ = 0.19 ±â€¯0.13 °C, p < 0.001) and associated with increased DIT during EBL (r = 0.43, p = 0.01, ß = 31 kcal/day/0.1 °C) and FNP (r = 0.60, p = 0.002, ß = 43 kcal/day/0.1 °C), but not CNP (p = 0.47). A ceiling effect for the increase in CBT, but not in DIT, was observed during feeding and, particularly, overfeeding. CONCLUSIONS: CBT increases with feeding and is moderately associated with DIT to a different degree depending on the macronutrient composition of the overfeeding diet. There is a ceiling effect such that individuals with a higher CBT during fasting have limited capacity to increase CBT with feeding. Because of body thermoregulatory mechanisms that maintain a constant CBT, these results indicate that CBT has a limited role in the inter-individual variability in DIT.

Label-free fluorescent discrimination and detection of epinephrine and dopamine based on bioinspired in situ copolymers and excitation wavelength switch.

A simple and label-free fluorescence turn-on method is proposed for the discrimination and detection of epinephrine (Ep) and dopamine (DA) via polyethyleneimine (PEI)-initiated in situ copolymerization and excitation wavelength switch. The PEI solution in the presence of Ep, DA and the mixture of Ep and DA are denoted as PEp-PEI, PDA-PEI and MEp+DA, respectively. In this study, PEI aqueous solution medium initiates the auto-oxidization of Ep and DA and the bioinspired copolymerization. These resultant copolymers emit yellow-green fluorescence color with a fluorescence emission maximum at 515 nm. Interestingly, these fluorescent copolymers exhibit distinct different excitation spectra, although Ep and DA are structurally very similar. PDA-PEI exhibits only one excitation peak at 385 nm, and PEp-PEI shows dual-excitation mode with two significant excitation peaks at 328 nm and 405 nm, respectively. MEp+DA also shows dual-excitation mode with two excitation peaks at 330 nm and 395 nm, respectively. Thus, individual Ep, DA, and their mixture can be discriminated based on the different excitation spectral shapes and peak locations of PEp-PEI, PDA-PEI and MEp+DA. Furthermore, the quantitative analysis of Ep and DA in mixture can also be achieved by switching excitation wavelength between 330 and 395 nm and monitoring the fluorescence emission intensity of MEp+DA at 515 nm. The fluorescence intensity of MEp+DA only related to the concentration of Ep when excited at 330 nm. Moreover, the concentration of DA can also be calculated by subtracting the fluorescence intensity of PEp-PEI from the total fluorescence intensity when excited at 395 nm. The resultant method has been used to simultaneously detect Ep and DA in human urine samples. The proposed fluorescence system is facile, eco-friendly, low-cost, and time-saving, and also provides a new and simple path for discriminating analogues.

Absence of gut microbial colonization attenuates the sympathoadrenal response to hypoglycemic stress in mice: implications for human neonates.

BACKGROUND: Gut microbiota plays an important role during early development via bidirectional gut-brain signaling. Catecholamines provide a survival advantage allowing adaptation to common postnatal stressors. We aimed to explore the potential link between gut microbiota/gut-derived metabolites and sympathoadrenal stress responsivity. METHODS: The effect of insulin-induced hypoglycemia was compared in mice with (control, adapted control) and without microbiome (germ-free, GF). Counter-regulatory hormones were analyzed in urine and plasma. Adrenal gene expression levels were evaluated and correlated to cecal short chain fatty acids (SCFA) content. RESULTS: There was a significant association between absent microbiota/SCFA and epinephrine levels at baseline and after stress. Corticosterone (hypothalamic-pituitary-adrenal axis) and glucagon release (parasympathetic signaling) were similar in all groups. Hypoglycemia-induced c-Fos (marker of trans-synaptic neuronal activation) in both conditions. Delayed increases in adrenal tyrosine hydroxylase and neuropeptide Y messenger RNA were observed in GF mice. Transcriptome analysis provided insight into underlying mechanisms for attenuated epinephrine production and release. CONCLUSION: Lack of microbiome selectively impaired adrenal catecholamine responses to hypoglycemia. We speculate that absent/delayed acquisition of flora (e.g., after antibiotic exposure) may compromise sympathoadrenal stress responsivity. Conversely, controlled manipulation of the intestinal microflora may provide a novel therapeutic opportunity to improve survival and overall health in preterm neonates.