<p>AIMTo establish a method for determinate of the inhibitory activity of angiotensin-converting enzyme inhibitor captopril by high performance capillary electrophoresis.p><p>METHODSThe characteristic absorptive wavelength of hippuric acid determined by ultraviolet spectrophotometer is 228 nm. The method employed a melted capillary column, 50 mmol.L-1 phosphoric acid (pH 8.3) buffer solution, inject pressure 4.8 kPa, inject time 3 s, separation voltage 20 kV and detection wavelength 228 nm.p><p>RESULTSThe reactant and resultant was separated completed within 7 min. IC50 of captopril was 0.019 mumol.L-1. Captopril is a competitive inhibitor, which was proved by enzyme reaction dynamics.p><p>CONCLUSIONThe method was shown to be accurate, simple and rapid and can be used for determination of the inhibitory activity of captopril.p>
Angiotensin-Converting Enzyme Inhibitors ; pharmacology ; Captopril ; pharmacology ; Electrophoresis, Capillary ; methods ; Hippurates ; analysis ; Peptidyl-Dipeptidase A ; metabolism

Renal Na+, K+-activated adenosinetriphosphatase (Na-K-ATPase) activity and the p-aminohippurate (PAH) transport kinetics were studied in uninephrectomized rats and cold exposed hamsters. In rats, the specific activity of renal Na-K-ATPase increased by approximately 50% in one week after uninephrectomy and remained more or less constant during the next three weeks. The capacity (Jmax) of PAH influx into the renal cortical slice was sharply increased in one week after nephrectomy, but after which it returned to the control level. In cold exposed hamsters, the specific activity of renal Na-K-ATPase did not increase until 48 days of cold exposure at which time it reached approximately 50% above the control level. On the other hand, the Jmax of PAH influx increased by about 80% in 10 days of co1d exposure and somewhat declined thereafter. These results suggest that PAH active transport in the renal slice is not ratelimited by the activity of Na-K-ATPase under physiological conditions.
Aminohippuric Acids/metabolism* ; Animal ; Biological Transport, Active ; Female ; Hamsters ; Hibernation ; Kidney/enzymology* ; Male ; Na(+)-K(+)-Exchanging ATPase/metabolism* ; Nephrectomy ; Rats ; p-Aminohippuric Acid/metabolism*

The effect of sodium on p-aminohippurate (PAH) transport kinetics was studied in isolated rat kidney slices in an attempt to define the role of sodium ion in renal organic acid transport. 1. In normally metabolizing renal slices, Na+ increased the Vmax of PAH influx without changing the Michaelis constant (Km). On the other hand, the effIux of preaccumulated PAH was reduced as the Na+ concentration increased. 2. In metabolically impaired renal slices, Na+ had no apparent effect on the influx and efflux of PAH. These results may indicate that Na+ is important for the energy transducing reaction in the PAH transport process.
Aminohippuric Acids/metabolism* ; Animal ; Biological Transport, Active/drug effects ; Culture Media ; Female ; In Vitro ; Kidney/metabolism* ; Kinetics ; Male ; Organ Culture ; Rats ; Sodium/pharmacology* ; p-Aminohippuric Acid/metabolism*

OBJECTIVES: In this study, we summarized the External Quality Assessment Scheme (EQAS) for the biological monitoring of occupational exposure to toxic chemicals which started in 1995 and continued until a 31st round robin in the spring of 2010. The program was performed twice per year until 2009, and this was changed to once a year since 2010. The objective of the program is to ensure the reliability of the data related to biological monitoring from analytical laboratories. METHODS: One hundred and eighteen laboratories participated in the 31st round robin. The program offers 5 items for inorganic analysis: lead in blood, cadmium in blood, manganese in blood, cadmium in urine, and mercury in urine. It also offers 10 items for organic analysis, including hippuric acid, methylhippuric acid, mandelic acid, phenylglyoxylic acid, N-methylformamide, N-methylacetamide, trichloroacetic acid, total trichloro-compounds, trans,trans-muconic acid, and 2,5-hexanedione in urine. Target values were determined by statistical analysis using consensus values. All the data, such as chromatograms and calibration curves, were reviewed by the committee. RESULTS: The proficiency rate was below 70% prior to the first round robin and improved to over 90% for common items, such as PbB and HA, while those for other items still remained in the range of 60-90% and need to be improved up to 90%. CONCLUSION: The EQAS has taken a primary role in improving the reliability of analytical data. A total quality assurance scheme is suggested, including the validation of technical documentation for the whole analytical procedure.
Acetamides ; Cadmium ; Calibration ; Consensus ; Dietary Sucrose ; Environmental Monitoring ; Formamides ; Glyoxylates ; Hexanones ; Hippurates ; Mandelic Acids ; Manganese ; Occupational Exposure ; Songbirds ; Sorbic Acid ; Trichloroacetic Acid

OBJECTIVE: The objetive of this study is to assess the level of oxidative stress by the exposure to volatile organic compounds (VOCs) and polycyclic aromatic hydrocarbons (PAHs) in volunteers who cleaned up the crude oil spilled from the Hebei Spirit on the Coast of Taean County, Korea. METHODS: The study subjects were 46 volunteers and 37 controls from the National Institute of Environmental Research. A self-administered questionnaire was used for volunteers to examine their working environment and health effects. Urinary concentrations of hippuric acid, 1-hydroxypyrene, and 2-naphthol were measured as exposure markers for VOCs and PAHs, and urinary thiobarbituric acid reactive substances (TBARS) and 8-hydroxydeoxyguanosine (8-OHdG) levels were measured as oxidative stress markers. RESULTS: Sixty-four percent of the respondents presented a variety of symptoms, including sore eyes and throat, nausea, dizziness, headache, low back pain, and leg pain after participating in the cleanup operation. Urinary 2-naphthol and TBARS concentrations appeared higher in the volunteers. Univariate and multivariate analyses showed that urinary TBARS and 8-OHdG levels were positively correlated with urinary 2-naphthol and 1-hydroxypyrene concentrations respectively, especially among the volunteers. CONCLUSIONS: The result implies that participating in cleanup work of oil spills may have a possibility to induce oxidative damage by exposure to PAHs in crude oil.
Data Collection ; Deoxyguanosine ; Dizziness ; Eye ; Headache ; Hippurates ; Korea ; Leg ; Low Back Pain ; Multivariate Analysis ; Naphthols ; Nausea ; Oxidative Stress ; Petroleum ; Petroleum Pollution ; Pharynx ; Polycyclic Hydrocarbons, Aromatic ; Pyrenes ; Questionnaires ; Thiobarbiturates ; Thiobarbituric Acid Reactive Substances ; Volatile Organic Compounds

Epidemiologic studies have suggested the association between environmental exposure to volatile organic compounds (VOCs) and polycyclic aromatic hydrocarbons (PAHs) and the increased risk of incurring asthma. Yet there is little data regarding the relationship between personal exposure to air pollution and the incidence of asthma in children. This study was designed to evaluate the effect of exposure to air pollution on children with asthma by using exposure biomarkers. We assessed the exposure level to VOCs by measuring urinary concentrations of hippuric acid and muconic acid, and PAHs by 1-OH pyrene and 2-naphthol in 30 children with asthma and 30 children without asthma (control). The mean level of hippuric acid was 0.158+/-0.169micromol/mol creatinine in the asthma group and 0.148+/-0.249micromol/mol creatinine in the control group, with no statistical significance noted (p=0.30). The mean concentration of muconic acid was higher in the asthma group than in the control group (7.630+/-8.915micromol/mol creatinine vs. 3.390+/-4.526micromol/mol creatinine p=0.01). The mean level of urinary 1-OHP was higher in the asthma group (0.430+/-0.343micromol/mol creatinine) than the control group (0.239+/-0.175micromol/mol creatinine), which was statistically significant (p=0.03). There was no difference in the mean concentration of 2-NAP between the two groups (9.864+/-10.037micromol/mol in the asthma group vs. 9.157+/-9.640micromol/mol in the control group, p=0.96). In conclusion, this study suggests that VOCs and PAHs have some role in asthma.
Air Pollutants/*pharmacology ; Asthma/*physiopathology/urine ; Case-Control Studies ; Child, Preschool ; Creatinine/urine ; Female ; Hippurates/urine ; Humans ; Male ; Naphthols/urine ; Organic Chemicals/chemistry/*pharmacology ; Polycyclic Hydrocarbons, Aromatic/*pharmacology ; Pyrenes/metabolism ; Sorbic Acid/*analogs & derivatives/metabolism ; Volatilization

OBJECTIVES: Automobile exhaust gases contain benzene and toluene, which are excreted in human urine as trans,trans-muconic acid and hippuric acid, respectively. Sorbic acid and benzoic acid, used as food preservatives, are also metabolized into trans,trans-muconic acid and hippuric acid in the human body. The purpose of this study is to estimate the level of benzene and toluene exposure according to the commuting mode and duration, residential environment, and preservative-added foods intake in university students who are not occupationally exposed to benzene or toluene. METHODS: Spot urine samples were collected from 211 university students who had no occupational exposure to volatile organic compounds. Information about their smoking history, residence type, traffic environments, commuting mode and duration, and their intake of bottled or canned food or beverages was gathered through a self-administered questionnaire. Urinary concentrations of trans,trans-muconic acid and hippuric acid were measured and statistically correlated to the individual's life style factors. RESULTS: There was no significant difference in the urinary concentrations of trans,trans-muconic acid or hippuric acid according to the smoking history. Mean urinary concentration of hippuric acid in females was higher than that found in males. Subjects living in districts with a population density of 1,000~4,999 people/km2 showed the highest urinary hippuric acid level; individuals living in cities of 5,000~9,999 people/km2 population density were next. The mean urinary trans,trans-muconic acid concentration was higher in students who were living where traffic jams are common compared to those who did not, and in subjects whose residence were within 149 m from a 4-lane road compared to those whose residence was not. However, neither mode nor duration of the commute showed any effect on the urinary trans,trans-muconic acid or hippuric acid concentrations of the students. Urinary hippuric acid levels increased when consuming canned fruit or canned coffee, and urinary trans,trans-muconic acid levels increased when consuming fruit juices or pickled radishes. CONCLUSIONS: The inhalation of vehicle exhaust and the ingestion of canned or pickled food may increase urinary hippuric acid and trans,trans-muconic acid levels in individuals who are not occupationally exposed to benzene or toluene.
Benzene ; Benzoic Acid ; Beverages ; Coffee ; Eating ; Female ; Food Preservatives ; Food, Preserved ; Fruit ; Gases ; Hippurates ; Human Body ; Humans ; Inhalation ; Life Style ; Male ; Occupational Exposure ; Occupations ; Population Density ; Questionnaires ; Smoke ; Smoking ; Sorbic Acid ; Toluene ; Transportation ; Vehicle Emissions ; Volatile Organic Compounds

This study was undertaken to determine whether verapamil protects renal function in rabbits with ischemic acute renal failure. Renal ischemia was induced by clamping bilateral renal arteries for 60 min. One group received intravenously an infusion of verapamil (lmg/kg) for 30 min prior to initiation of renal artery clamping and the other group received equal volume of saline. Renal blood flow was measured with flowmeter before (basal) and 24 hr after ischemia. Serum creatinine level increased 24 hr after ischemia and remained high to 72 hr. When verapamil was pretreated, the level 48 and 72 hr after ischemia was significantly decreased compared with saline insusion. Urine flow was markedly decreased 24 hr after ischemia and remained depressed to 72 hr, but it was significantly increased 72 hr after ischemia in verapa- mil-pretreatment animals as compared with the saline-infusion animals. GFR were markedly reduced 24 hr after ischemia and remained depressed to 72 hr, which was significantly prevented by verapamil pretreatment. Ischemia caused a significant increase in FEVa and a reduction in Uosm, and TcH2O, indicating impairment in urine concentrating ability of tubules, and the impairment was significantly attenuated by verapamil. The uptake of p-aminohippurate in cortical slices was depressed by ischemia, which was significantly prevented by verapamil pretreatment. In salineinfusion animals, renal blood flow was not significantly different between the basal value and that after 24 hr of reflow. Renal blood flow was not significantly altered by verapamil pretreatment. Anoxia/reoxygenation injury in the control renal slices was not significantly prevented by Ca channel blockers. These results suggest that verapamil exerts a protective effect in ichemic acute renal failure, and the beneficial effects may be attributed to effects other than vasodilation. These data also indicate that a reduction in GFR following ischemia does not result from change in renal blood flow.
Acute Kidney Injury* ; Animals ; Constriction ; Creatinine ; Flowmeters ; Ischemia ; Kidney Concentrating Ability ; p-Aminohippuric Acid ; Rabbits* ; Renal Artery ; Renal Circulation ; Vasodilation ; Verapamil*

The organic anion transporters (OAT) have recently been identified. Although the some transport properties of OATs in the kidney have been verified, the regulatory mechanisms for OAT's functions are still not fully understood. The rat OAT1 (rOAT1) transports a number of negatively charged organic compounds between the cells and their extracellular milieu. Caveolin (Cav) also plays a role in membrane transport. Therefore, we investigated the protein-protein interactions between rOAT1 and caveolin-2. In the rat kidney, the expressions of rOAT1 mRNA and protein were observed in both the cortex and the outer medulla. With respect to Cav-2, the expressions of mRNA and protein were observed in all portions of the kidney (cortex < outer medulla = inner medulla). The results of Western blot analysis using the isolated caveolae-enriched membrane fractions or the immunoprecipitates by respective antibodies from the rat kidney showed that rOAT1 and Cav-2 co-localized in the same fractions and they formed complexes each other. These results were confirmed by performing confocal microscopy with immunocytochemistry using the primary cultured renal proximal tubular cells. When the synthesized cRNA of rOAT1 along with the antisense oligodeoxynucleotides of Xenopus Cav-2 were co-injected into Xenopus oocytes, the [14C]p-aminohippurate and [3H]methotrexate uptake was slightly, but significantly decreased. The similar results were also observed in rOAT1 over-expressed Chinese hamster ovary cells. These findings suggest that rOAT1 and caveolin-2 are co-expressed in the plasma membrane and rOAT1's function for organic compound transport is upregulated by Cav-2 in the normal physiological condition.
Animals ; Biological Transport, Active/*physiology ; CHO Cells ; Caveolins/*metabolism ; Cell Membrane/*metabolism ; Cells, Cultured ; Hamsters ; Immunoprecipitation ; Kidney Tubules, Proximal/*metabolism ; Methotrexate/metabolism ; Microscopy, Confocal ; Oligonucleotides, Antisense/pharmacology ; Oocytes/metabolism ; Organic Anion Transport Protein 1/antagonists & inhibitors/genetics/*metabolism ; RNA, Complementary/metabolism ; RNA, Messenger/genetics/metabolism ; Rats ; Research Support, Non-U.S. Gov't ; Xenopus laevis/metabolism ; p-Aminohippuric Acid/metabolism