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At least 19 recordsLinked to original sources
PubMed1979

[Investigations on 131I-hippurate-clearance in obstructive-uropathy; extraction of para-aminohippuric acid and 131I-hippurate in the acutely obstructed canine kidney (author's transl)].

The results of more recent clinical and experimental investigations have thrown doubt on the usefulness of determining the individual 131I-hippurate clearance for evaluation of the function of acutely obstructed kidneys. There is a significant difference (5% level) between the kidney performance determined with external measurement on the one hand and with PAH and 125I-hippurate clearance in the steady state on the other. With the steady state method, the restriction of function to be expected in consequence of urinary obstruction is demonstrated, whereas with simultaneous measurement with catheterless 131I-hippurate clearance, an increase in function is detected. In the clearance studies carried out in the conventional way with PAH and 125I-hippurate, it was difficult to determine quantitatively the urine produced during urinary obstruction. The renal extraction of p-aminohippuric acid and 131I-hippurate was therefore determined in simultaneous measurement in six dogs before and after acute urinary obstruction with a constant plasma level of the test substances. The results obtained with this very elaborate method which is, however, independent of urine collection show that an acute urinary obstruction leads to a decrease of renal extraction both of PAH and of 131I-hippurate. Since with conventional clearance, the measurement result is proportional to the amount of substance excreted with the urine, a restriction of function must also result with the steady state methods in determining the performance of acutely obstructed kidneys. The results of the extraction investigations hence confirm the results of the clearance studies mentioned. In addition, they show that the "increase" of renal performance immediately after an experimentally induced urinary obstruction repeatedly found with catheterless determination of 131I-hippurate-clearance cannot be explained by a different kinetic behavior of PAH and 131I-hippurate in the acutely obstructed kidney.

Acute Disease↗
PubMed1991

A new derivatization procedure for the analysis of hippuric acid and m-methyl-hippuric acid by gas chromatography.

The industrial solvents, toluene and xylene, have physicochemical properties that can be hazardous to the workers exposed. Since hippuric acid and m-methyl-hippuric acid represent the products of toluene and xylene biotransformation in urine, they are used as biological markers in studies on occupational exposure to these solvents. Several methods have been used to determine hippuric acid and m-methyl-hippuric acid--either based on gas chromatography or on high-performance liquid chromatography. In this study we propose the derivatization of hippuric acid and methyl-hippuric acid using methanol in acid medium (HCl), a low-cost reagent with a low level of toxicity. The method has been routinely used in our laboratory for 1 year and has proven to be a reliable procedure for the biological control of occupational exposure to toluene and/or xylene.

Chromatography, Gas↗
PubMed1989

Renal clearance of substituted hippurates in the dog. I. Benzoylglycine (hippurate) and methyl-substituted benzoylglycines.

Plasma kinetics and renal excretion of benzoylglycine (hippurate) and methyl-substituted benzoylglycines were studied in three Beagle dogs, after rapid i.v. administration of about 1 g of glycine conjugate. Benzoylglycine and the 3- and 4-methyl analogs showed nonlinear plasma protein binding varying between 20 and 80% over a concentration range of 5 to 450 micrograms/ml. For 2-methylbenzoylglycine an extremely high protein binding, practically approaching 100%, was observed at low plasma levels (less than 50 micrograms/ml). All conjugates were cleared largely via the kidney (greater than 80% of the dose) and, except for the 2-methyl analog, eliminated rapidly from plasma. Plasma concentration and renal excretion rate data were analyzed simultaneously with a previously developed physiologically based kidney model. Tubular secretion appeared to be a function of the total drug concentration in renal plasma, except for 2-methylbenzoylglycine, presumably due to its tight protein binding. The average values of the parameters characterizing the tubular transport maximum (TM in milligrams per minute) and the apparent affinity for the secretory system (KT in micrograms per milliliter) were: benzoylglycine TM = 5.5 +/- 0.8, KT = 40 +/- 5; 3-methylbenzoylglycine TM = 7.1 +/- 3.3, KT = 49 +/- 1; 4-methylbenzoylglycine TM = 8.0 +/- 1.6, KT = 14 +/- 6. Secretion of 2-methylbenzoylglycine was not saturated. Accordingly, only the ratio TM/KT = 163 +/- 54 ml/min could be calculated. An interesting observation was the partial deconjugation of 4-methylbenzoylglycine to its corresponding benzoate.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Analysis of plasma hippurate in humans using gas chromatography-mass spectrometry: concentration and incorporation of infused [15N]glycine.

To allow in vivo determination of synthetic rates for individual proteins, physiological incorporation of infused [15N]glycine into urinary hippuric acid has been used as an indicator of intrahepatic tracer dilution. Although the kidneys might contribute to hippurate production, the relationship between hepatic, plasma, and urinary hippurate has not yet been established in humans. To further investigate these issues we developed a fast, sensitive, and reliable method for measuring simultaneously hippurate concentrations and in vivo tracer incorporation into hippurate in plasma and urine using stable isotopes and gas chromatography-mass spectrometry. We then tested this assay under several experimental conditions. Reference compounds [( 15N]- and [ring-2H5]hippurate) were synthesized and gave linear standard curves. Postabsorptive hippurate plasma levels in healthy subjects ranged from 1.2 to 10.5 microM and protein binding was 79 +/- 6% (mean +/- SD). Following a bolus dose of [15N]glycine tracer appeared in plasma hippurate; enrichment in hippurate was indistinguishable from that in glycine after an equilibration period of 20 min, indicating a close relationship between intracellular glycine and plasma hippurate. A 16-h infusion of [15N]glycine resulted in identical enrichment levels in urinary and plasma hippurate; glycine enrichment in a hepatic export protein (VLDL-ApoB) was approaching plasma hippurate but not plasma free glycine enrichment. The ability to monitor plasma hippurate is of practical advantage compared to the sampling of urine. Furthermore it allows the monitoring of rapid events in the intrahepatic dilution of an infused glycine tracer. This assay may, therefore, become an important tool in the study of hepatic protein metabolism.

Administration, Oral↗
PubMed1978

Binding of hippurate in normal plasma and in uremic plasma pre- and postdialysis.

The protein binding of 14C-hippurate has been measured by conventional ultrafiltration techniques in the plasma of normal subjects and in uremic subjects pre- and postdialysis. In addition, the clearance of 14C-hippurate was determined in vitro in both isotonic saline and plasma to assess binding limitations on hippurate removal during dialysis. Binding levels of hippurate in normal subjects of 68+/-1.8% (n = 5) were significantly higher than either postdialysis (48.3+/-15.4%; n = 7) or predialysis (36.6+/-11.7%; n = 7) levels in the same uremic subjects. Actual levels of plasma hippurate were, however, considerably greater in uremics (24.7+/-11.2 mg/dl' n = 7) than in normal subjects (congruent to 0.5 mg%). The difference in hippurate binding between pre- and postdialysis samples in uremics was significantly different from zero (p less than 0.01, t = 5.36), indicating depletion of competitive site-binding species during dialysis. The saline clearance of hippuric acid (99.1 +/-0.5 ml/min; n = 6) under standard conditions in a capillary dialyzer (CDAK-4) was consistent with the expected clearance of a solute of its molecular weight. Hippurate clearance in citrated plasma, where binding was determined as 50+/-3%, was 65+/-0.7 ml/min (n = 6), in good agreement with a theoretically predicted clearance of 60 ml/min for this level of binding. High serum levels of hippurate and its derivatives, may depress effective function of various organs. In addition to the normal dietary intake of hippurate and its precursors, patients on dialysis receive a further burden of hippurate precursor in the form of benzyl alcohol, the common preservative in heparin solutions. The large body burdens of hippurate in dialysis patients, coupled with its impaired removal on dialysis due to binding, point to the necessity for a through investigation of the potential toxicity of this compound.

Carbon Radioisotopes↗
PubMed1987

Prevalence and characterization of hippurate-negative Campylobacter jejuni in King County, Washington.

A total of 593 strains of thermophilic Campylobacter species were isolated either from humans with diarrhea or from poultry in King County, Washington. Of these strains, 98 (52 hippurate-positive strains and all 46 of the hippurate-negative strains) were selected for further phenotypic characterization and genetic classification. Hippurate hydrolysis, the test typically used to differentiate Campylobacter jejuni and C. coli, did not always correlate with the genetic classification. All hippurate-positive strains were classified as C. jejuni. Of the hippurate-negative strains, 20% were C. jejuni, 78% were C. coli, and 2% were C. laridis. Assuming that the remaining hippurate-positive strains were all C. jejuni, then hippurate-negative C. jejuni represented a small percentage (9 of 556 or 1.6%) of C. jejuni strains but a significant percentage (9 of 46 or 20%) of hippurate-negative strains. This finding suggests that hippurate hydrolysis should not be used as the sole criterion for differentiating thermophilic Campylobacter species, particularly when describing the disease states associated with these organisms.

Animals↗
PubMed1977

The synthesis of hippurate from benzoate and glycine by rat liver mitochondria. Submitochondrial localization and kinetics.

1. Rat liver mitochondria make hippurate at up to 4 nmol/min per mg of protein. The rate of synthesis supported by oxidation of glutamate with exogenous Pi present is identical with that supported by ATP plus oligomycin. Lower rates were obtained with other respiratory substrates, and when glutamate was used without Pi. 2. A matrix localization for hippurate synthesis is indicated by the latency of benzoyl-CoA synthetase and glycine N-acyltransferase to their extramitochondrial substrates, failure of exogenous benzoyl-CoA to inhibit incorporation of [14C]hippurate and inhibition of hippurate synthesis supported by ATP, but not glutamate, by carboxyatractyloside. 3. The relative activities of the individual enzymes and the mitochondrial content of benzoyl-CoA in the presence and absence of glycine suggest that hippurate synthesis is rate-limited by formation of benzoyl-CoA. 4. The increases in rates of ATP hydrolysis and of O2 consumption on the addition of benzoate and glycine were in good agreement with those required to support hippurate synthesis. The increase in respiration indicates that State-4 respiration [Chance & Williams (1957) Adv. Enzymol 17, 65-134] is not used, with these conditions, for ATP synthesis.

Adenosine Triphosphate↗
PubMed1988

Correlation of a colorimetric and a HPLC method for the determination of serum hippuric acid concentrations in uremia.

Hippuric acid has been recognized as a potential marker of uremic toxicity in chronic renal failure. However, in most studies, serum hippuric acid concentrations have been determined by sophisticated methods, such as high-performance liquid chromatography. The present study was undertaken to evaluate whether the less complicated colorimetric determination method could replace such methods. Based on 21 different samples, the results obtained by both methods appeared to be correlated to each other in a highly significant way (total hippuric acid: r = 0.99, p less than 0.001; free hippuric acid; r = 1.00, p less than 0.001). Mean total and free hippuric acid concentrations and mean percent protein binding, obtained with both determination methods, were also identical. It is concluded that both the colorimetric method and high-performance liquid chromatography are equally reliable for the study of the concentration of hippuric acid in uremic serum and of its importance as a marker of the clinical and biochemical epiphenomena of uremic toxicity.

Chromatography, High Pressure Liquid↗
PubMed1987

Hippurate participation in the inhibition of glucose utilization in renal failure.

Patients with renal insufficiency suffer from inhibited glucose utilization which can be tested in vitro by the incubation of tissues or isolated cells in diluted uraemic serum. 1. Systematic isolation from the serum of patients with renal insufficiency has revealed that hippurate participates in the inhibition of glucose utilization in the muscle and, to a lesser extent, in the kidney. It does not inhibit glucose utilization in the brain, red blood cells and platelets. 2. Maximal inhibition is 86.6% and AD50 is 0.432 mmol hippurate/l. These hippurate concentrations are achieved in the early stages of renal insufficiency. 3. While the inhibitory effect is evident at normal and elevated glucose concentrations, it does not manifest itself at hypoglycaemic concentrations. 4. A less pronounced inhibitory effect, compared with hippurate, is exerted also by O-OH hippurate, but it is absent altogether in P-amino-hippurate and O-OH hippuryl-beta-glucuronide. It is concluded that, through its inhibition of glucose utilization, hippurate may participate in the development of muscular weakness in patients with renal insufficiency.

Animals↗
PubMedDate not supplied

Long-term treatment with methenamine hippurate in recurrent urinary tract infection.

Twenty-four patients with a history of recurrent urinary tract infection and in whom residual urine was considered to be a factor of importance for chronicity, have been treated for an average of 16 months with 1 g methenamine hippurate morning and evening. No patient had urinary calculus at the commencement of treatment and neither did any patient have an indwelling catheter. In patients without urinary tract infection or in whom abacteriuria was achieved with methenamine hippurate, the number of reinfections was reduced by approximately two thirds compared to periods prior to treatment. No patient was completely free from infection throughout the whole treatment period. However, in no case did bacteria with extensive resistance appear. When urinary tract infection was treated with methenamine hippurate, abacteriuria was achieved in only 6 of 14 patients. It would therefore seem that this agent is only of limited value for treatment of established infection. In the event of manifest infection it would appear appropriate to treat the infection primarily with antibiotics and to use methenamine hippurate for prophylaxis when abacteriuria has been achieved. No patient developed urinary calculus during treatment with methenamine hippurate and no deterioration of renal function or haematological change was observed.

Adult↗
PubMed1986

Two-dimensional thin-layer chromatography for the specific detection of hippurate hydrolysis by microorganisms.

Glycine, one of the end products of hippurate hydrolysis by microorganisms, was detected by a rapid, specific technique utilizing two-dimensional thin-layer chromatography. A loopful of growth of each organism from its suitable agar medium was washed, suspended, and incubated with 0.1% sodium hippurate for 30 min at 37 degrees C. The supernatant of the incubated suspension from each organism was then dansylated, and the dansyl derivatives were separated by two-dimensional thin-layer chromatography on polyamide sheets. Glycine, a product of hippurate hydrolysis, was detected under UV light. This technique does not require prolonged incubation and was found to be more specific and reliable than the standard ninhydrin reaction. In addition, it is inexpensive and can be easily conducted in a clinical microbiological reference laboratory. By this method, 100% (22/22) of Campylobacter jejuni and 0% (0/9) of Campylobacter coli reference strains were positive. In addition, 100% (13/13) of group B streptococci, 100% (24/24) of group D streptococci, and 90% (18/20) of Gardenerella vaginalis clinical isolates were positive for hippurate hydrolysis. This method is useful for the identification to the species level of Campylobacter organisms and the biotyping of Gardnerella organisms and for the detection of hippurate hydrolysis by unknown microorganisms.

Bacteria↗
PubMed1987

Prevention of recurrent acute cystitis by methenamine hippurate: double blind controlled crossover long term study.

In a randomised, double blind, long term, crossover study 1 g twice daily of methenamine hippurate was compared with placebo for its preventive effect on recurrent attacks of acute cystitis. Methenamine hippurate and placebo were interchanged every six months for two years. During one of the years patients took 250 ml extra fluid every morning and evening. Out of 21 enrolled patients, 14 completed the first year and 13 both years of treatment, which permitted the evaluation of 27 patient years. There were 52 episodes of acute cystitis caused by reinfection: 41 occurred during placebo treatment and only 11 during the methenamine hippurate regimen (p less than 0.01). Extra fluid intake did not reduce the incidence of acute cystitis, nor did it reduce the effect of methenamine hippurate. Methenamine hippurate is an effective prophylactic agent against recurrent acute cystitis and has the advantage of not inducing cross resistance to conventional antibiotics.

Acute Disease↗
PubMed1976

Post-mortem survival of hippuric acid formation in rat and human cadaver tissue samples.

1. A rapid and sensitive semi-micro method for the determination of hippuric acid formation by tissue samples in vitro is described and applied to the determination of the post-mortem survival of hippuric acid formation in rat and human cadaver tissue samples. 2. Hippuric acid formation survived in rat and human cadaver liver for at least 72 h when corpses were stored at 4 degrees. 3. Hippuric acid formation was detected in human cadaver liver and kidney samples and was absent from brain, intestine, heart and lung. 4. Post-mortem liver samples from a case of acute pancreatitis failed to form hippuric acid as did kidney samples from a case of systemic lupus erythematosus with renal involvement.

Adult↗
PubMed1991

Effect of hippurate on glucose utilization in rat kidney cortex slices.

Hippurate action on glucose utilization was evaluated in rat kidney cortex slices. Studies have shown the following. (1) Hippurate inhibits markedly basal as well as insulin-stimulated glucose utilization and basal gluconeogenesis. (2) Ca deficiency and specific Ca channel blockers diltiazem and isradipine abolish the hippurate inhibition of glucose utilization. (3) K+ channel blockers, i.e. the increased K+ concentration in incubation medium, procaine and sulfonylurea drugs also abolish the hippurate inhibition of glucose utilization. It is concluded that hippurate and benzoate operate through the ATP-dependent K+ channel.

Animals↗
PubMed1983

Prognostic value of post-transplant hippurate scintigraphy.

131Iodine hippurate sequential scintigrams obtained after transplantation contain prognostic information about the long-term development of a graft. Results of 131 131iodine hippurate sequential scintigrams made within 48 hours after graft implantation were compared to the graft status 2 years after transplantation. Hippurate uptake and transport were rated on a 4-step scale. Disturbed hippurate uptake and abnormal tracer transit were associated with increased frequency of early graft destruction and with a high frequency of chronic rejection. The chi-square test demonstrated a significant relationship between results of the initial hippurate scintigrams and long-term graft development.

Adolescent↗