Hippuric Acid Concentration Research Articles

Method development and validation for simultaneous quantitation of endogenous hippuric acid and phenylacetylglycine in rat urine using liquid chromatography coupled with electrospray ionization tandem mass spectrometry.

Urinary hippuric acid (HA) and phenylacetylglycine (PAG) are biomarker candidates for drug-induced phospholipidosis (PLD). To confirm their utility in preclinical and clinical settings, it is essential to develop and validate their quantification method in advance. In this study, we have applied liquid chromatography-tandem mass spectrometry (LC/MS/MS) for simultaneous quantification of HA and PAG in rat urine, and matrix based ion suppression was assessed by post-column infusion assay. Effective sample dilution reduced matrix effect of urine to be negligible level and calibration curves showed good correlation between those in urine diluent and buffer alone. Reliability of this assay was confirmed by the assessments for intra- and inter-day precisions and accuracies of quality control samples. The method was applied to rat urine after multiple oral administrations of PLD-inducing drugs, and the changes in HA and PAG concentrations and their ratio were successfully detected as rat plasma in previous report. This is the first report to quantify HA and PAG easily and accurately as potential biomarkers to monitor PLD status. This assay would be useful tool for monitoring PLD in toxicological studies by non-invasive sampling.

Cyanidin 3-glucoside improves diet-induced metabolic syndrome in rats

Increased consumption of dark-coloured fruits and vegetables may mitigate metabolic syndrome. This study has determined the changes in metabolic parameters, and in cardiovascular and liver structure and function, following chronic administration of either cyanidin 3-glucoside (CG) or Queen Garnet plum juice (QG) containing cyanidin glycosides to rats fed either a corn starch (C) or a high-carbohydrate, high-fat (H) diet. Eight to nine-week-old male Wistar rats were randomly divided into six groups for 16-week feeding with C, C with CG or QG, H or H with CG or QG. C or H were supplemented with CG or QG at a dose of ∼8mg/kg/day cyanidin glycosides from week 8 to 16. H rats developed signs of metabolic syndrome including visceral adiposity, impaired glucose tolerance, hypertension, cardiovascular remodelling, increased collagen deposition in left ventricle, non-alcoholic fatty liver disease, increased plasma liver enzymes and increased inflammatory cell infiltration in the heart and liver. Both CG and QG reversed these cardiovascular, liver and metabolic signs. However, no intact anthocyanins or common methylated/conjugated metabolites could be detected in the plasma samples and plasma hippuric acid concentrations were unchanged. Our results suggest CG is the most likely mediator of the responses to QG but that further investigation of the pharmacokinetics of oral CG in rats is required.

In situ N2O emissions are not mitigated by hippuric and benzoic acids under denitrifying conditions

Ruminant urine patches deposited onto pasture are a significant source of greenhouse gas nitrous oxide (N2O) from livestock agriculture. Increasing food demand is predicted to lead to a rise in ruminant numbers globally, which, in turn will result in elevated levels of urine-derived N2O. Therefore mitigation strategies are urgently needed. Urine contains hippuric acid and together with one of its breakdown products, benzoic acid, has previously been linked to mitigating N2O emissions from urine patches in laboratory studies. However, the sole field study to date found no effect of hippuric and benzoic acid concentration on N2O emissions. Therefore the aim of this study was to investigate the in situ effect of these urine constituents on N2O emissions under conditions conducive to denitrification losses. Unadulterated bovine urine (0mM of hippuric acid, U) was applied, as well as urine amended with either benzoic acid (96mM, U+BA) or varying rates of hippuric acid (8 and 82mM, U+HA1, U+HA2). Soil inorganic nitrogen (N) and N2O fluxes were monitored over a 66day period. Urine application resulted in elevated N2O flux for 44days. The largest N2O fluxes accounting for between 13% (U) and 26% (U+HA1) of total loss were observed on the day of urine application. Between 0.9 and 1.3% of urine-N was lost as N2O. Cumulative N2O loss from the control was 0.3kgN2O–Nha−1 compared with 11, 9, 12, and 10kgN2O–Nha−1 for the U, U+HA1, U+HA2, and U+BA treatments, respectively. Incremental increases in urine HA or increase in BA concentrations had no effect on N2O emissions. Although simulation of dietary manipulation to reduce N2O emissions through altering individual urine constituents appears to have no effect, there may be other manipulations such as reducing N content or inclusion of synthetic inhibitory products that warrant further investigation.

Consumption of anthocyanin-rich Queen Garnet plum juice reduces platelet activation related thrombogenesis in healthy volunteers

The anti-thrombotic properties of an anthocyanin-rich Queen Garnet plum juice (QGPJ) and anthocyanin-free prune juice (PJ) were studied in this randomised, double-blind, crossover trial. Twenty-one healthy subjects (M = 10, F = 11) consumed QGPJ, PJ or placebo, 200 mL/day for 28-days followed by a 2-week wash-out period. Only QGPJ supplementation inhibited platelet aggregation induced by ADP (<5%, P = 0.02), collagen (<2.7%, P < 0.001) and arachidonic acid (<4%, P < 0.001); reduced platelet activation-dependent surface-marker P-selectin expression of activated de-granulated platelets (<17.2%, P = 0.04); prolonged activated-partial thromboplastin clotting time (>2.1 s, P = 0.03); reduced plasma-fibrinogen (<7.5%, P = 0.02) and malondialdehyde levels, a plasma biomarker of oxidative stress (P = 0.016). PJ supplementation increased plasma hippuric acid content (P = 0.018). QGPJ or PJ supplementation did not affect blood cell counts, lipid profile, or inflammation markers. Our findings suggest that QGPJ but not PJ has the potential to significantly attenuate thrombosis by reducing platelet activation/hyper-coagulability and oxidative stress.

Abstract C13: Use of air monitoring and urine biomarker assays to measure geographic disparities in exposure to VOCs in Washington, DC

Abstract The District of Columbia has one of the highest cancer incidence and mortality rates in the nation in conjunction with significant cancer-related geographic and racial disparities. Increased exposure to environmental carcinogens, such as benzene, in high risk areas of DC is of public health importance and may play a role in these disparities in cancer incidences and mortality rates. Volatile Organic Compounds (VOC), such as toluene and benzene, are absorbed by the body and undergo metabolism to produce bio-activated (can lead to cancer and other serious health effects) metabolites that are excreted from the body via the urine and/or feces. Air monitoring and urinary biomarker assays are accepted methods for exposure assessment of VOCs but little is known regarding the correlation between the two. In this study we compared the urinary concentrations of hippuric acid and t,t-muconic acid (two known benzene and toluene metabolites, respectively) with indoor and outdoor exposure levels of toluene and benzene in high risk (&amp;lt;1 mile from highway/freeway) and low risk urban areas (&amp;gt;3 miles from the highway/freeway) in Washington, DC. First morning void urine samples were collected from 16 adult residents in high risk areas and 14 adult residents in low risk areas after 72 hours of air monitoring. Urine samples were sent to NMS laboratory and metabolite levels were measured using liquid chromatography/ mass spectrometry. Indoor and outdoor benzene and toluene levels were measured in the same homes over 72 hours using a 3M Organic Vapor Monitor and analyzed using gas chromatograph mass spectrometer (GC/MS). t,t-muconic acid urinary concentration levels in normal non-exposed individuals has been previously reported at .0001g/l and hippuric acid levels have been reported at &amp;lt;1.4 g/l. In our study participants, mean levels of urinary t,t-muconic and hippuric acid were .0003g/l and .35 g/l, respectively. Toluene levels, as measured by air monitoring, indoors (-0.34, p=0.08) and outdoors (-0.004, p=0.98) were both negatively correlated with urinary hippuric acid levels. A negative correlation was also observed between outdoor benzene levels and t,t-muconic acid (-0.23, p =0.11), however indoor levels showed a positive correlation with the urinary biomarker (0.13, p =0.52). We also observed higher levels of t,t-muconic acid in the high risk residents (87.17g/gCR) compared to low risk residents (59.54 g/gCR; p =0 .56). The positive correlation between indoor benzene levels and urinary t,t-muconic acid levels suggest the presence of additional sources of benzene inside the homes. Though air levels of VOCs are a good indicator of exposure, urinary metabolites may give a more measure of VOC exposure. Although not statistically significant, we observed a disparity in exposure to VOCs in “high risk” versus “low risk” areas in Washington, DC. Citation Format: Ashley Corrin Huderson, Chiranjeev Dash, Lucile Adams-Campbell. Use of air monitoring and urine biomarker assays to measure geographic disparities in exposure to VOCs in Washington, DC. [abstract]. In: Proceedings of the Sixth AACR Conference: The Science of Cancer Health Disparities; Dec 6–9, 2013; Atlanta, GA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2014;23(11 Suppl):Abstract nr C13. doi:10.1158/1538-7755.DISP13-C13

Heterogeneous electrochemical immunoassay of hippuric acid on the electrodeposited organic films.

By directly coordinating hippuric acid (HA) to the ferrate (Fe) as an electron transfer mediator, we synthesized a Fe-HA complex, which shows a good electrochemical signal and thus enables the electrochemical immunoanalysis for HA. We electrodeposited organic films containing imidazole groups on the electrode surface and then bonded Ni ion (positive charge) to induce immobilization of Fe-HA (negative charge) through the electrostatic interaction. The heterogeneous competitive immunoassay system relies on the interaction between immobilized Fe-HA antigen conjugate and free HA antigen to its antibody (anti-HA). The electric signal becomes weaker due to the hindered electron transfer reaction when a large-sized HA antibody is bound onto the Fe-HA. However, in the presence of HA, the electric signal increases because free HA competitively reacts with the HA antibody prior to actual reaction and thus prevents the HA antibody from interacting with Fe-HA at the electrode surface. This competition reaction enabled an electrochemical quantitative analysis of HA concentration with a detection limit of 0.5 μg mL−1, and thus allowed us to develop a simple and rapid electrochemical immunosensor.

Hippuric Acid Levels in Paint Workers at Steel Furniture Manufacturers in Thailand

BackgroundThe aims of this study were to determine hippuric acid levels in urine samples, airborne toluene levels, acute and chronic neurological symptoms, and to describe any correlation between urinary hippuric acid and airborne toluene.MethodsThe hippuric acid concentration in the urine of 87 paint workers exposed to toluene at work (exposed group), and 87 nonexposed people (control group) was studied. Study participants were selected from similar factories in the same region. Urine samples were collected at the end of a shift and analyzed for hippuric acid by high performance liquid chromatography. Air samples for the estimation of toluene exposure were collected with diffusive personal samplers and the toluene quantified using gas–liquid chromatography. The two groups were also interviewed and observed about their work practices and health.ResultsThe median of the 87 airborne toluene levels was 55 ppm (range, 12–198 ppm). The median urinary hippuric acid level was 800 mg/g creatinine (range, 90–2547 mg/g creatinine). A statistically significant positive correlation was found between airborne toluene exposure and urine hippuric acid levels (r = 0.548, p < 0.01). Workers with acute symptoms had significantly higher hippuric acid levels than those who did not (p < 0.05). It was concluded that there was a significant correlation between toluene exposure, hippuric acid levels, and health (p < 0.001).ConclusionThere appears to be a significant correlation between workers exposure to toluene at work, their urine hippuric acid levels, and resulting symptoms of poor health. Improvements in working conditions and occupational health education are required at these workplaces. There was good correlation between urinary hippuric acid and airborne toluene levels.

SCREENING OF BIOLOGICAL ACTIVITIES FROM NOSTOC SPP. (CYANOPHYTA)

Screening of antioxidant activity (AA), total polysaccharide content (TPC) and angiotensin I-converting enzyme (ACE) inhibitor from Nostoc spp., maintained at TISTR Algal Culture Collection (TISTR-ACC) was conducted. The AA was tested by free radical scavenging of lipid phase (antioxidant capacity of lipid-soluble compounds-ACL) against superoxide anion (O2) using photochemiluminescence (PCL) assay. From seventy-one samples of crude extracts, N. punctiforme TISTR 8167 showed the best AA of 481.55 µmol (Trolox equivalent)/g (crude extract), followed by N. parmelioides TISTR 8174, Nostoc sp. TISTR 9102, N. paludosum TISTR 9004, Nostoc sp. TISTR 9073 and N. commune TISTR 8870, the activities of which were in the range of 348-390 µmol (Trolox equivalents)/g (crude extract). The total polysaccharide content (TPC) was determined by phenol-sulfuric acid assay. From fifty-two samples, the high TPC at ≥120 mg g-1 (dry cell weight), were found in three strains. The highest TPC at 130 mg g-1 was obtained from N. commune TISTR 8299. Angiotensin I-converting enzyme inhibitory activity (ACE-IA) and soluble protein content (SPC) of Nostoc strains were determined from 70 to 58 samples, respectively. The ACE-IA was tested by the detection of hippuric acid (HA) content from the reaction between hippuryl-histidyl-leucine (HHL) and ACE in the presence or absence of ACE inhibitor through simulated digestion of the samples. The results revealed that the high activities in the range 78-86% were obtained from N. commune TISTR 8160, N. muscorum TISTR 8164, N. paludosum TISTR 8890, N. entophylum TISTR 8161 and N. punctiforme TISTR 8167, by which N. commune TISTR 8160 expressed the highest inhibitory activity at 86%. The results of SPC quantified by Bradford assay were in the range 0.03-1.41 mg ml-1, N. micro-scopicum TISTR 9078, exhibited the highest SPC among the tested samples. However, these results show no relationship between ACE-IA and SPC.

Pharmacokinetic study of benfotiamine and the bioavailability assessment compared to thiamine hydrochloride

Benfotiamine is a lipid-soluble thiamine precursor which can transform to thiamine in vivo and subsequently be metabolized to thiamine monophosphate (TMP) and thiamine diphosphate (TDP). This study investigated the pharmacokinetic profiles of thiamine and its phosphorylated metabolites after single- and multiple-dose administration of benfotiamine in healthy Chinese volunteers, and assessed the bioavailability of orally benfotiamine administration compared to thiamine hydrochloride. In addition, concentration of hippuric acid in urine which is produced in the transformation process of benfotiamine was determined. The results showed that thiamine and its phosphorylated metabolites exhibited different pharmacokinetic characteristics in plasma, blood and erythrocyte, and one-compartment model provided the best fit for pharmacokinetic profiles of thiamine. The transformation process of benfotiamine to thiamine produced large amount of hippuric acid. No accumulation of hippuric acid was observed after multiple-dose of benfotiamine. Compared to thiamine hydrochloride, the bioavailability of thiamine in plasma and TDP in erythrocyte after oral administration of benfotiamine were 1147.3 ± 490.3% and 195.8 ± 33.8%, respectively. The absorption rate and extent of benfotiamine systemic availability of thiamine were significantly increased indicating higher bioavailability of thiamine from oral dose of benfotiamine compared to oral dose of thiamine hydrochloride.

Postprandial response on fatty meal is affected by sea buckthorn (Hippophaë rhamnoides) supplementation: NMR metabolomics study

Nuclear magnetic resonance fingerprinting (1H NMR) combined with different statistical tools was used to assess the effect of phenolics-rich sea buckthorn berries on postprandial plasma and urine after consumption of a fatty meal and to obtain information about the absorption and excretion of ethyl-O-β-d-glucopyranoside and various inositols in sea buckthorn berries. Analyses of plasma samples indicated the delayed postprandial increase of lipid levels and the restrained increase of 3-hydroxy butanoic acid and N-acetyl glycoproteins when sea buckthorn meal was compared to control. The rise of acetic acid concentration and the occurrence of methyl-O-β-d-glucopyranoside and ethyl-O-β-d-glucopyranoside, but no inositols, were noticed after sea buckthorn meal in plasma. The methylglucoside was detected for the first time in plasma in relation to sea buckthorn containing diet, and the compound has subsequently been identified for the first time in sea buckthorn. Analyses of postprandial urine samples revealed a lower creatinine and dimethylamine concentrations and a higher hippuric acid concentration in urine after the berry meal when compared to the control. Excretion of the ethylglucoside in urine was detected after the sea buckthorn meal which indicates that this alkyl sugar is not efficiently metabolized by human body.

Xylene-Induced Auditory Dysfunction in Humans

Animal data indicate that xylene induces cochlear dysfunction, characterized by the loss of outer hair cells. There is little evidence regarding xylene-induced ototoxicity in humans. The aim of the study was to investigate the possible adverse effects of xylene on the peripheral and central auditory system in humans. A total of 30 medical laboratory workers who had been exposed to a mixture of xylene isomers, together with 30 nonexposed control participants matched for gender, age, and educational level were selected. Participants of both groups were not exposed to noise levels above 85 dBA time-weighted average. All participants were evaluated with a comprehensive audiological test battery, which included measures of peripheral and central auditory function. Peripheral auditory measures included pure-tone audiometry and distortion product otoacoustic emissions. Behavioral measures of central auditory function included a pitch pattern sequence test, an adaptive test of temporal resolution, a dichotic digit test, and a masking level difference test. The auditory brainstem response was used to objectively evaluate the function of the auditory pathways at the brainstem level. Speech perception in quiet and in noise was evaluated using the Hearing In Noise Test (HINT). The xylene-exposed participants were extensively evaluated with regard to their exposure to both noise and xylene. Noise dosimetry was conducted over an 8-hr work shift to obtain noise-exposure levels for each xylene-exposed worker. Airborne xylene concentrations were obtained at 11 different workstations throughout the medical laboratories, and methyl hippuric acid levels per gram of creatinine in urine were obtained for each xylene-exposed subject. Finally, a detailed interview exploring current and past solvent and noise exposure was conducted. The xylene-exposed participants showed significantly worse pure-tone thresholds in comparison with the nonexposed participants. The xylene-exposed participants demonstrated significantly worse results than the control group participants for the pitch pattern sequence test, dichotic digit test, HINT, and the auditory brainstem response (absolute and interpeak latencies). No significant differences between the xylene-exposed and nonexposed participants were observed for distortion product otoacoustic emissions, adaptive test of temporal resolution, or the masking level difference test. A significant correlation between the concentrations of methyl hippuric acid in urine and pure-tone thresholds (2 to 8 kHz) was found in xylene-exposed workers. Also, participants with high cumulative dose of xylene exposure presented with poorer test results than participants with low cumulative dose of xylene exposure. The results of the present research suggest that xylene is associated with adverse central auditory effects and poorer sound detection abilities in humans. A major limitation of the study is that the results found among xylene-exposed participants cannot be proved to be permanent, and thus further research should be conducted to clarify this limitation. Workers exposed to this chemical should be routinely evaluated with a comprehensive audiological test battery, to detect early signs of auditory dysfunction.

Lonicera caerulea fruits reduce UVA-induced damage in hairless mice

UVA photons are less energetic than UVB photons but they are more abundant in solar radiation. Modern tools have shown that UVA light has serious adverse effects on the skin. We investigated the effect of consuming Lonicera caerulea berries on UVA-induced damage in SKH-1 mice. The mice were fed a diet containing L. caerulea berries (10%, w/w) for 14days before a single UVA (30J/cm2) treatment. Effects on haematological and antioxidant parameters were evaluated 4 and 24h after irradiation. The bioavailability of L. caerulea phenolics was also assessed. Consuming the L. caerulea berry-enriched diet caused reduced malondialdehyde production and increased catalase activity and glutathione levels were found in skin and erythrocytes. UVA-induced NADPH:quinone oxidoreductase-1 and gamma-L-glutamate-L-cysteine ligase protein in skin were reduced in mice fed L. caerulea berries. Enhanced heme oxygenase-1 level in skin, interleukin-17 in plasma and reduced interleukin-12 levels in plasma were found in the mice on the experimental diet. Histological (pyknotic) changes in the nuclei of basal cells induced by UVA exposure were reduced in L. caerulea berry consuming animals. HLPC-MS analysis showed high concentrations of hippuric acid, one of the main metabolites of aromatic amino acids and phenolic compounds, in skin, liver, urine and faeces of mice consuming the berries.Taken together, consumption of L. caerulea berries affords protection from the adverse effects of a single UVA exposure mainly via modulation of antioxidant parameters.

Direct Inhibition and Down-regulation by Uremic Plasma Components of Hepatic Uptake Transporter for SN-38, an Active Metabolite of Irinotecan, in Humans

Clinical study has previously revealed that plasma concentration of 7-ethyl-10-hydroxycamptothecin (SN-38), an active metabolite of irinotecan, was higher in patients with end-stage renal failure than those with normal kidney function although SN-38 is mainly eliminated in the liver. Here, we focused on inhibition by uremic toxins of hepatic SN-38 uptake and down-regulation of uptake transporter(s) by uremic plasma in humans. We evaluated SN-38 uptake and its inhibition by uremic toxins, 3-carboxy-4-methyl-5-propyl-2-furanpropionate (CMPF), indoxyl sulfate (Indox), hippuric acid (HA) and indole acetate (IA), with cryopreserved human hepatocytes and HEK293 cells stably expressing hepatic uptake transporters, organic anion transporting polypeptides (OATPs). We also collected plasma samples from patients with severe renal failure to examine their effects on mRNA level of OATPs in primary cultured human hepatocytes. SN-38 was taken up by hepatocytes, which showed biphasic saturation patterns. The SN-38 uptake by hepatocytes was significantly inhibited by a uremic toxin mixture including clinically relevant concentrations of CMPF, Indox, HA and IA. Kinetic analyses for OATP-mediated transport revealed that the uptake of SN-38 by OATP1B1 was the highest, followed by OATP1B3. Among the uremic toxins, CMPF exhibited most potent inhibition of OATP1B1-mediated SN-38 uptake and directly inhibited the uptake of SN-38 also in hepatocytes. In addition, gene expression of OATP1B1 and OATP1B3 in hepatocytes was significantly down-regulated by the treatment with the uremic plasma. OATP1B1-mediated hepatic uptake of SN-38 was inhibited by uremic toxins, and gene expression of OATP1B1 was down-regulated by uremic plasma.

Consumption of foods containing cyanogenic glycosides: A study on bioavailability of cyanide in humans

Nuclear magnetic resonance fingerprinting (1H NMR) combined with different statistical tools was used to assess the effect of phenolics-rich sea buckthorn berries on postprandial plasma and urine after consumption of a fatty meal and to obtain information about the absorption and excretion of ethyl-O-β-d-glucopyranoside and various inositols in sea buckthorn berries. Analyses of plasma samples indicated the delayed postprandial increase of lipid levels and the restrained increase of 3-hydroxy butanoic acid and N-acetyl glycoproteins when sea buckthorn meal was compared to control. The rise of acetic acid concentration and the occurrence of methyl-O-β-d-glucopyranoside and ethyl-O-β-d-glucopyranoside, but no inositols, were noticed after sea buckthorn meal in plasma. The methylglucoside was detected for the first time in plasma in relation to sea buckthorn containing diet, and the compound has subsequently been identified for the first time in sea buckthorn. Analyses of postprandial urine samples revealed a lower creatinine and dimethylamine concentrations and a higher hippuric acid concentration in urine after the berry meal when compared to the control. Excretion of the ethylglucoside in urine was detected after the sea buckthorn meal which indicates that this alkyl sugar is not efficiently metabolized by human body.

Evaluation of hippuric acid content in goat milk as a marker of feeding regimen

Organic producers, traders, and consumers must address 2 issues related to milk: authentication of the production system and nutritional differentiation. The presence of hippuric acid (HA) in goat milk samples has been proposed as a possible marker to differentiate the feeding regimen of goats. The objective of this work is to check the hypothesis that HA could be a marker for the type of feeding regimen of goats by studying the influence of production system (conventional or organic) and feeding regimen (with or without grazing fodder). With this purpose, commercial cow and goat milk samples (n=27) and raw goat milk samples (n=185; collected from different breeds, localizations, and dates) were analyzed. Samples were grouped according to breed, feeding regimen, production system, and origin to compare HA content by ANOVA and honestly significant difference Tukey test at a confidence level of ≥95%. Hippuric acid content was obtained by analyzing milk samples with capillary electrophoresis. This method was validated by analyzing part of the samples with HPLC as a reference technique. Sixty-nine raw goat milk samples (of the total 158 samples analyzed in this work) were quantified by capillary electrophoresis. In these samples, the lowest average content for HA was 7±3mg/L. This value corresponds to a group of conventional raw milk samples from goats fed with compound feed. The highest value of this group was 28±10mg/L, corresponding to goats fed compound feed plus grass. Conversely, for organic raw goat milk samples, the highest concentration was 67±14mg/L, which corresponds to goats fed grass. By contrast, the lowest value of this organic group was 26±10mg/L, which belongs to goats fed organic compounds. Notice that the highest HA average content was found in samples from grazing animals corresponding to the organic group. This result suggests that HA is a good marker to determine the type of goats feeding regimen; a high content of HA represents a diet based mainly or exclusively on eating green grass (grazing), independently of the production system. Hence, this marker would not be useful for the actual organic policies to distinguish organic milk under the current regulations, because organic dairy ruminants can be fed organic compound feed and conserved fodder without grazing at all.

Homogeneous Electrochemical Detection of Hippuric Acid in Urine Based on the Osmium–Antigen Conjugate

A homogeneous electrochemical immunoassay is based on the interaction of osmium-antigen conjugate with its antibody. The novelty presented herein is the direct conjugation of the osmium complex to a small antigen and the application of the quantitative analysis of the antigen and its antibody as the electrical signal for homogeneous immunoassay. The small antigen chosen is hippuric acid (HA), a major urinary metabolite in toluene-exposed humans. As a redox mediator, [Os(4,4'-dimethoxy-2,2'-bipyridine)2(4-aminomethylpyridine-HA)Cl](+/2+) (Os-HA antigen) has been synthesized and characterized on screen-printed carbon electrodes. The synthesized Os-HA antigen shows reversible redox peaks at E(½)=0.056 V versus Ag/AgCl. The homogeneous competitive immunoassay relies on the interaction between Os-HA antigen conjugate and free antigen to its antibody, which can generate electrical signals linearly proportional to the free antigen monitored by cyclic voltammetry and differential pulse voltammetry in the range of 10 μg mL(-1) to 5.12 mg mL(-1). The cutoff concentration of HA in urine samples is 2.0 mg mL(-1), so the method can be used to develop a HA immunosensor. Moreover, the proposed homogeneous electrochemical immunoassay method can be applied to detect low concentrations of small antigens found in the healthcare area.

Pharmacokinetic study of multiple active constituents after oral gavage of Guizhi decoction in rats using a LC–MS/MS method

Guizhi decoction (GZD) is a classic traditional Chinese medicine formula, clinically used for the treatment of influenza, common cold, and other pyretic conditions. A sensitive, specific, and validated liquid chromatography-tandem mass spectrometric (LC-MS/MS) method was developed to investigate the pharmacokinetic properties of cinnamic acid, hippuric acid, paeoniflorin, and glycyrrhetic acid in rat. After single dose oral administration of 7.9 g extract/kg body weight GZD in rats, plasma concentrations of cinnamic acid, hippuric acid, paeoniflorin, and glycyrrhetic acid were measured by LC-MS/MS. Pharmacokinetic parameters were calculated from the plasma concentration-time data. The values of AUC0-t, half-life (t 1/2), and C max were 7.2 ± 2.3 μg h/mL, 1.2 ± 0.3 h, and 9.2 ± 5.2 μg/mL for cinnamic acid, 53 ± 31 μg h/mL, 2.8 ± 2.0 h, and 17 ± 3 μg/mL for hippuric acid, 1.1 ± 0.5 μg h/mL, 1.9 ± 1.1 h, and 0.6 ± 0.3 μg/mL for paeoniflorin, and 11 ± 6 μg h/mL, 6.6 ± 2.5 h, and 0.9 ± 0.6 μg/mL for glycyrrhetic acid, respectively. The results would offer useful information for effective components of GZD in vivo.

Hippuric acid as a significant regulator of supersaturation in calcium oxalate lithiasis: the physiological evidence.

At present, the clinical significance of existing physicochemical and biological evidence and especially the results we have obtained from our previous in vitro experiments have been analyzed, and we have come to the conclusion that hippuric acid (C6H5CONHCH2COOH) is a very active solvent of Calcium Oxalate (CaOX) in physiological solutions. Two types of experiments have been discussed: clinical laboratory analysis on the urine excretion of hippuric acid (HA) in patients with CaOX lithiasis and detailed measurements of the kinetics of the dissolution of CaOX calculi in artificial urine, containing various concentrations of HA. It turns out that the most probable value of the HA concentration in the control group is approximately ten times higher than the corresponding value in the group of the stone-formers. Our in vitro analytical measurements demonstrate even a possibility to dissolve CaOX stones in human urine, in which increased concentration of HA have been established. A conclusion can be that drowning out HA is a significant regulator of CaOX supersaturation and thus a regulation of CaOX stone formation in human urine. Discussions have arisen to use increased concentration of HA in urine both as a solubilizator of CaOX stones in the urinary tract and on the purpose of a prolonged metaphylactic treatment.

Antimicrobial Activity of Hippurate Nanocomposite and Its Cytotoxicity Effect in Combination with Cytarabine against HL‐60

Hippuric acid (HA) was intercalated into a zinc‐layered hydroxide (ZLH) by direct reaction of an aqueous suspension of zinc oxide with an aqueous solution of hippuric acid to obtain hippurate nanocomposite (HAN). Various concentrations of hippuric acid (0.05, 0.2, and 0.4 molar) were used for the synthesis of the nanocomposite. The as‐synthesized HAN using 0.2 molar was found to give a well‐ordered layered nanocomposite material with an increase in the basal spacing to 21.3 Å which indicated the insertion of hippurate organic moiety into the ZLH interlayers. The cytotoxicity of HAN in combination with cytarabine against human promyelocytic leukemia cells (HL‐60) was tested using MTT cell viability assay and trypan blue dye exclusion assay. The combination of cytarabine with HAN showed higher tumor suppression efficiency as compared to that of cytarabine alone. The IC50 values of HAN/cytarabine combination and cytarabine alone were 0.16 ± 0.07 μg/mL and 0.17 ± 0.09 μg/mL, respectively. DNA fragmentation was also studied, and the exposure of HL‐60 cells to cytarabine produced 10.70 ± 0.96% DNA fragmentation compared to 18.90 ± 1.33% when cells were exposed to combination of cytarabine with HAN. The antimicrobial activity of hippuric acid and HAN nanocomposite was carried out against Gram‐positive bacteria, Gram‐negative bacteria, and yeasts. It was found that Pseudomonas aeruginosa and methicillin‐resistant Staphylococcus aureus were more sensitive to HAN compared to Bacillus subtilis and Salmonella choleraesuis.

The New Danger of Thirdhand Smoke: Why Passive Smoking Does Not Stop at Secondhand Smoke

Passive smoking exposure is a topic of great concern for public health because of its well-known adverse effects on human health (International Agency for Research on Cancer 2004). Two news articles on this topic were published in the February 2011 issue of Environmental Health Perspectives (Burton 2011; Lubick 2011). Lubick (2011) discussed the global health burden of secondhand smoke, and Burton (2011) emphasized a new and alarming consequence of smoking in indoor environments—“thirdhand smoke”—a term first coined in 2006 (Szabo 2006). Secondhand smoke is defined as “the combination of smoke emitted from the burning end of a cigarette or other tobacco products and smoke exhaled by the smoker” (World Health Organization 2007). Thus, secondhand smoke exposure consists of an unintentional inhalation of smoke that occurs close to people smoking and/or in indoor environments where tobacco was recently used. Thirdhand smoke is a complex phenomenon resulting from residual tobacco smoke pollutants that adhere to the clothing and hair of smokers and to surfaces, furnishings, and dust in indoor environments. These pollutants persist long after the clearing of secondhand smoke. They are reemitted into the gas phase or react with oxidants or other compounds present in the environment to form secondary contaminants, some of which are carcinogenic or otherwise toxic for human health (Matt et al. 2011). Thus, thirdhand smoke exposure consists of unintentional intake (mainly through inhalation but also via ingestion and dermal routes) of tobacco smoke and other related chemicals that occurs in the absence of concurrent smoking. Exposure can even take place long after smoking has ceased, through close contact with smokers and in indoor environments in which tobacco is regularly smoked. Lubick (2011) considers secondhand smoke synonymous with passive smoking, as do the majority of the authors publishing on this topic. However, in light of new evidence about thirdhand smoke (Matt et al. 2011), it is no longer appropriate to use the term “secondhand smoke” as a synonym for passive smoking or environmental tobacco smoke, because it represents a pars pro toto. In other words, using the term “secondhand smoke” mistakes one part of the problem for the whole. Instead, we propose that “passive smoking” or “environmental tobacco smoke” be used as a more inclusive term to describe any tobacco smoke exposure outside of active smoking. This question of terminology is of particular concern for researchers evaluating passive smoking exposure in indoor settings, especially in domestic environments. Since numerous countries have introduced smoking bans in enclosed public places, domestic environments have become the main sources of passive smoking exposure (World Health Organization 2007). We believe researchers should determine the independent contributions of secondhand and thirdhand smoke when they assess the magnitude of pollutant intake due to passive smoking exposure.