SEARCH · PubMed Health

Results for “acetate”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources

PubMed1991

[Study of the processes of butyl acetate regeneration from butanol-butyl acetate solutions by etherification of butanol with acetic anhydride (for use in production of penicillins].

Etherification of butanol by acetic anhydride in butanol-butyl acetate mixtures containing 0.09 to 3 per cent water was investigated. A method for processing the butanol-butyl acetate mixtures with the weight part of butanol up to 16 per cent by etherification of the latter with acetic anhydride was developed, the yield being 96 to 97 per cent and the weight part being at least 97.5 per cent. On the basis of the estimate of the raw material use for regeneration of butyl acetate from the butanol-butyl acetate solutions by etherification of butanol with acetic anhydride, the technical and economic advantages of the processing of such solutions by the described method were shown.

Acetates↗

PubMed1991

Haematological effects in mice of the antitumour agents xanthenone-4-acetic acid, 5,6-dimethyl-xanthenone-4-acetic acid [correction of 5,6-methyl-] and flavone acetic acid.

Treatment of C57Bl/6 x DBA/2 mice with the maximal tolerated dose of flavone-8-acetic acid (FAA, 1300 mumol/kg), xanthenone-4-acetic acid (XAA, 1090 mumol/kg), or its dose-potent derivative 5,6-dimethyl-xanthenone-4-acetic acid (5,6-MeXAA, 100 mumol/kg) resulted within 24 h in a dramatic reduction in the number of circulating lymphocytes, an elevation in haemoglobin concentrations and a reduction in platelet numbers. Neutrophil counts either remained unchanged or were slightly elevated. All three compounds caused a marked loss of cells in the thymus. Examination of histological sections of thymus at 48 h following treatment with XAA revealed a selective depletion of cortical thymocytes and no effects on the epithelium or other thymic structures. A transient decrease in cell numbers was seen in the spleen and femoral bone marrow, with recovery to normal levels occurring within 3 days. The number of haemopoietic stem cells, colony-forming units in culture (CFU-c), in the femoral bone marrow increased after drug administration despite the occurrence of a decrease in the overall number of cells in the femur. In contrast to the increase in CFU-c numbers seen in vivo, 2 h exposure of bone-marrow cells to FAA, XAA or 5,6-MeXAA in vitro resulted in a decrease in the surviving fraction of CFU-c. The results are consistent with the hypothesis that the in vivo haematological effects of these compounds are indirect, perhaps being mediated through the induction of cytokines, and contrast with the haematological effects of conventional antitumour agents. The biochemical and haematological effects are unlikely to be the cause of the acute toxicity observed for these compounds.

Animals↗

PubMed1991

Plasma pharmacokinetics of the antitumour agents 5,6-dimethylxanthenone-4-acetic acid, xanthenone-4-acetic acid and flavone-8-acetic acid in mice.

Although the antitumour agent flavone-8-acetic acid (FAA) exhibits remarkable activity against murine solid tumours, its clinical use has a number of pharmacological drawbacks, including low dose potency and dose-dependent pharmacokinetics. Xanthenone-4-acetic acid (XAA) and its 5,6-dimethyl derivative (5,6-MeXAA) were synthesised during a search for better analogues of FAA. The maximal tolerated doses (MTDs) of 5,6-MeXAA, XAA and FAA in BDF1 mice were 99, 1,090 and 1,300 mumol/kg, respectively. At the MTD, 5,6-MeXAA displayed the following pharmacokinetic properties: maximal plasma concentration, 600 microM; mean residence time, 4.9 h; AUC, 2,400 mumol h 1-1; and volume of steady-state distribution, 0.2 l/kg. All compounds displayed nonlinear elimination kinetics at the MTD, but when the logarithm of the AUC was plotted against that of the delivered dose, the slope of the regression line for 5,6-MeXAA was found to be 1.2 as opposed to 1.4 for XAA and 1.98 for FAA. 5,6-MeXAA thus showed only a slight deviation from dose-independent kinetics. 5,6-MeXAA bound to plasma proteins in a manner similar to that exhibited by FAA, although the plasma concentration of free drug was lower for the former than for the latter. As a consequence, the calculated maximal free drug concentration for 5,6-MeXAA in plasma was 23 times lower than that for FAA.

Animals↗

PubMed1992

Disappearance of acetic acid from the bovine reticulorumen at basal and elevated concentrations of acetic acid.

Disappearance of acetic acid was quantified to determine whether removal of this acid from the reticulorumen is altered when ruminal acetic acid concentrations are elevated. Ruminally fistulated beef steers (n = 3 per experiment; BW = 320 +/- 9 kg) were fed eight times daily a 46% corn-based concentrate:54% mixed hay diet to meet maintenance energy requirements (3.5 kg of DM/d). In situ production of acetic acid, determined by pulsed-continuous infusion of [1-14C]acetic acid, was 530 mmol/h (CV = 12%). Disappearance from the reticulorumen (i.e., presumed absorption) was 460 mmol/h (CV = 2%) or 87% (CV = 2%) of ruminal production. Variation is described within an operational steady state. Acetic acid concentrations were increased by continuous infusion of unlabeled acetic acid into the reticulorumen. Ruminal disappearance (mmol/h) increased when this simulated production was elevated up to and exceeding in situ rates reported previously (530 to 2,700 mmol/h). These data suggest that two-thirds to three-fourths of ruminal acetate production disappeared across the reticuloruminal wall when concentration was elevated; the complement exited from the rumen with the liquid phase. The reticulorumen has an additional capacity to remove acetic acid; however, it does so with an apparent reduced efficiency at higher production rates. Liquid out-flow may affect the efficiency of reticuloruminal disappearance. Sites distal to the rumen become quantitatively important when ruminal acetic acid concentrations are increased.

Absorption↗

PubMed1990

Acetate tolerance and the kinetics of acetate utilization in diabetic and nondiabetic subjects.

We investigated acetate utilization in humans by randomly intravenously infusing acetate (2.5 mmol/min) or bicarbonate (2.8 mmol/min) over 60 min into nine nondiabetic and six non-insulin-dependent diabetic subjects followed with or without bolus intravenous glucose (20 g/m2 body surface area). The acetate metabolic clearance rate (MCR) was greater in the nondiabetic subjects (50.4 +/- 14.9 vs 25.0 +/- 6.5 mL.min-1.kg-1, p less than 0.01) as were acetate elimination rate constant (Kac) (0.031 +/- 0.003 vs 0.026 +/- 0.004/min, p less than 0.01) and basal turnover rate (8.56 +/- 3.65 vs 4.92 +/- 1.03 mumol.min-1.kg-1, p less than 0.01); acetate half-time was thus shorter in the nondiabetics (22.6 +/- 2.2 vs 27.2 +/- 3.8 min, p less than 0.01). Kac was reduced and half-time was prolonged in all the subjects (p less than 0.001) when glucose was available. Prior acetate or bicarbonate infusion had no influence on either the KG rate constant of glucose elimination or the postglucose insulin responses in both subject groups. These results suggest that the infused acetate did not worsen glucose tolerance, glucose impaired acetate utilization unlike reported in ruminants, and acetate is rapidly metabolized in humans although at a slower rate in diabetics.

Acetates↗

PubMed1979

Acetate intolerance and an inhibitor of acetate utilization in hemodialysis patients.

Diminished ability to utilize acetate (acetate intolerance) developed in a male patient on chronic hemodialysis after five years of maintenance dialysis. His ability to utilize lactate was also subnormal. We studied acetate metabolism in vitro by isolating lymphocytes from the patient's blood before dialysis and measuring their ability to convert [1-14C]acetate to 14CO2. His cells metabolized acetate only 35% as well as did lymphocytes from normal adults. The inhibition appeared when the patient's lymphocytes were cultured, and the ability of normal lymphocytes to oxidize acetate decreased after they had been incubated in the patient's plasma. We conclude that an inhibitor of acetate utilization is present in the plasma and in (or on) the cells of this acetate-intolerant patient. The diminished ability of the patient to utilize lactate and the presence of normal concentrations of pyruvate, citrate, and ketone bodies in his blood suggest that the inhibitor functions at the cell surface to impede the entrance of acetate into the cells. The inhibitor appears to be dialyzable; its nature is unknown. Its accumulation in the plasma of chronic hemodialysis patients has not been thus far associated with any deleterious effects other than prolonging the metabolic acidosis of such patients.

Acetates↗

PubMed1977

An energy-conserving pyruvate-to-acetate pathway in Entamoeba histolytica. Pyruvate synthase and a new acetate thiokinase.

Under anaerobic conditions, cells of Entamoeba histolytica grown with bacteria produce H2 and acetate while cells grown axenically produce neither. Aerobically, acetate is produced and O2 is consumed by amebae from either type of cells. Centrifuged extracts, 2.4 x 106 x g x min, from both types of cells contain pyruvate synthase (EC 1.2.7.1) and an acetate thiokinase which, together, form a system capable of converting pyruvate to acetate. Pyruvate synthase catalyzes the reaction: pyruvate + CoA leads to CO2 + acetyl-CoA + 2E. Electron acceptors which function with this enzyme are FAD, FMN, riboflavin, ferredoxin, and methyl viologen, but not NAD or NADP. The amebal acetate thiokinase catalyzes the reaction acetyl-CoA + ADP + Pi leads to acetate + ATP + CoA. For this apparently new enzyme we suggest the trivial name acetyl-CoA-synthetase (ADP-forming). Extracts from axenic amebae do not contain hydrogenase, but extracts from cells grown with bacteria do. It is postulated that in bacteria-grown amebae electrons generated at the pyruvate synthase step are utilized anaerobically to produce H2 via the hydrogenase and that the acetyl-CoA is converted to acetate in an energy-conserving step catalyzed by amebal acetyl-CoA synthetase. Aerobically, cells grown under either regimen may utilize the energy-conserving pyruvate-to-acetate pathway since O2 then serves as the ultimate electron acceptor.

Acetate-CoA Ligase↗

PubMed1990

Influence of progestins on serum hormone levels in postmenopausal women with advanced breast cancer--II. A differential effect of megestrol acetate and medroxyprogesterone acetate on serum estrone sulfate and sex hormone binding globulin.

Serum estradiol, estrone, estrone sulfate and sex hormone binding globulin were measured in 10 postmenopausal patients with advanced breast cancer receiving sequential treatment with medroxyprogesterone acetate and megestrol acetate. Treatment with megestrol acetate caused a non-significant reduction in serum estradiol (mean reduction of 19%, 0.05 less than P less than 0.1) but significant reductions in serum estrone (mean reduction of 20%, P less than 0.02) and serum estrone sulfate (mean reduction of 54%, P less than 0.005) compared to treatment with medroxyprogesterone acetate. In contrast, treatment with medroxyprogesterone acetate reduced serum sex hormone binding globulin more compared to treatment with megestrol acetate (mean reduction of 69%, P less than 0.01). These findings suggest that the two progestins have differential effects on serum hormone levels. The finding that treatment with megestrol acetate causes a significant reduction in serum estrone sulfate level warrants further investigations of this potentially important mechanism of action of this drug in advanced breast cancer.

Aged↗

PubMed1990

Comparison of growth, acetate production, and acetate inhibition of Escherichia coli strains in batch and fed-batch fermentations.

The growth characteristics and acetate production of several Escherichia coli strains were compared by using shake flasks, batch fermentations, and glucose-feedback-controlled fed-batch fermentations to assess the potential of each strain to grow at high cell densities. Of the E. coli strains tested, including JM105, B, W3110, W3100, HB101, DH1, CSH50, MC1060, JRG1046, and JRG1061, strains JM105 and B were found to have the greatest relative biomass accumulation, strain MC1060 accumulated the highest concentrations of acetic acid, and strain B had the highest growth rates under the conditions tested. In glucose-feedback-controlled fed-batch fermentations, strains B and JM105 produced only 2 g of acetate.liter-1 while accumulating up to 30 g of biomass.liter-1. Under identical conditions, strains HB101 and MC1060 accumulated less than 10 g of biomass.liter-1 and strain MC1060 produced 8 g of acetate.liter-1. The addition of various concentrations of sodium acetate to the growth medium resulted in a logarithmic decrease, with respect to acetate concentration, in the growth rates of E. coli JM105, JM105(pOS4201), and JRG1061. These data indicated that the growth of the E. coli strains was likely to be inhibited by the acetate they produced when grown on media containing glucose. A model for the inhibition of growth of E. coli by acetate was derived from these experiments to explain the inhibition of acetate on E. coli strains at neutral pH.

Acetates↗

PubMed1976

[Liver function tests under the influence of sequential treatment using ethinyl estradiol-norethisterone acetate and ethinyl estradiol-chlormadinone acetate].

30 young healthy women were investigated during the first therapy cycle with ethinyl-estradiol-norethisterone acetate and ethinyl-estradiol-chlormadinone acetate as a sequential regime. The following laboratory data were achieved by each of the investigated group of young women: serum aminotransferase (GOT and GPT), serum alkaline phosphatase and alpha-amylase-activity in serum, serum proteins, serum cholesterol, serum bilirubin, serum ZST, serum TTT and the indocyaningreen-clearance of the liver. The serum protein pattern was determined by the paper electrophoretic method. A significant decrease of the aminotransferase GPT was viable during the sequential therapy with ethinyl-estradiol and norethisterone acetate. This viable decrease of the GPT was induced through the application of norethisterone acetate to estrogen. The alkaline phosphatase was significant lightly lower and the beta-globuline lightly elevated at the end of the therapy cycle. The sequential therapy with ethinyl-estradiol and chlormadinone acetate induced only a significant increase of the ZST in serum.

Adolescent↗

PubMed1978

Methanogenesis from acetate: a nonmethanogenic bacterium from an anaerobic acetate enrichment.

A methanogenic acetate enrichment was initiated by inoculation of an acetate-mineral salts medium with domestic anaerobic digestor sludge and maintained by weekly transfer for 2 years. The enrichment culture contained a Methanosarcina and several obligately anaerobic nonmethanogenic bacteria. These latter organisms formed varying degrees of association with the Methanosarcina, ranging from the nutritionally fastidious gram-negative rod called the satellite bacterium to the nutritionally nonfastidious Eubacterium limosum. The satellite bacterium had growth requirements for amino acids, a peptide, a purine base, vitamin B12, and other B vitamins. Glucose, mannitol, starch, pyruvate, cysteine, lysine, leucine, isoleucine, arginine, and asparagine stimulated growth and hydrogen production. Acetate was neither incorporated nor metabolized by the satellite organism. Since acetate was the sole organic carbon source in the enrichment culture, organism(s) which metabolize acetate (such as the Methanosarcina) must produce substrates and growth factors for associated organisms which do not metabolize acetate.

Acetates↗

PubMed1992

Structure-activity relationships for substituted 9-oxo-9,10-dihydroacridine-4-acetic acids: analogues of the colon tumour active agent xanthenone-4-acetic acid.

A series of 9-oxo-9,10-dihydroacridine-4-acetic acids (acridone-4-acetic acids) were prepared by Jourdan-Ullmann condensation of 2-halobenzoic acids with 2-aminophenylacetic acids, followed by H2SO4-induced cyclodehydration of the resulting 2-[2-(carboxymethyl)phenylamino]benzoic acids. These were evaluated for their ability to induce haemorrhagic necrosis in transplanted colon 38 tumours in mice, using a short-term histology assay. The results broadly paralleled those seen previously for xanthenone-4-acetic acids, with 1-, 2- and 7-substitution being dystherapeutic, and substitution at the 5- and 6-positions by lipophilic groups increasing activity. While some analogues were as active as xanthenone-4-acetic acids in the histology assay and gave significant growth delays against colon 38 tumours in vivo, as a class the 9-oxo-9,10-dihydroacridine-4-acetic acids were generally less potent than the xanthenone-4-acetic acids.

Animals↗

PubMed1990

Measurement of stable isotopic enrichment of underivatized acetate by gas chromatography/mass spectrometry: application to in vivo estimation of acetate production.

In order to assess endogenous and colonic production of acetate, we have developed an assay for determining the isotopic enrichment of plasma acetate using gas chromatography/mass spectrometry (GC/MS). Acidified, deproteinized plasma (200 microliters) was extracted into ethyl ether, and the ether phase was then injected into a gas chromatograph/mass spectrometer fitted with a 30 m x 0.252 mm i.d. capillary column (temperature program 50-245 degrees C at 10 degrees C min-1). Using electron impact GC/MS and selected ion monitoring, peak areas of ions with m/z 60 and 61 (M + 1) were determined. Triplicate extractions of enriched plasma samples (mol.% excess 1.38-1.5%) resulted in a coefficient of variation of 1.6-5.9%. Unenriched plasma samples were found to have an enrichment close to theoretical natural abundance, and analysis of our (1-13C)acetate tracer (99 at.% excess) revealed an ion at m/z 61 and no ion at m/z 60. To verify accuracy, we conducted an in vivo isotope dilution study. In a 1-month-old piglet, fasted for 24 h, changing the rate of a 4 h infusion (mmol h-1) of (1-13C)acetate from 0.141 to 0.282 doubled the isotope enrichment (2.08 x) of the second plateau. The rate of appearance of acetate was 26.0 mumols kg-1 min-1, which is comparable to that reported in fasting sheep.

Acetates↗

PubMed1977

Comparison of the biological activity of the tumor promotor phorbol myristate acetate and a metabolite, phorbolol myristate acetate, in the cell culture.

Phorbolol myristate acetate, a metabolite of the tumor promotor phorbol muristate acetate in mouse skin, has one-fiftieth the potency of the parent molecule for the induction of cell division in stationary cultures of BALB/c-3T3 mouse embryo cells. Similarly, in a mixed cell culture assay devised for detection of tumor-promoting agents, phorbolol myristate acetate exhibited only a small fraction of the activity of unmetabolized phorbol ester. The results indicate that the biological activity of phorbol esters either does not require metabolic conversion or is converted by the cells used in this system and that phorbolol myristate acetate would be a tumor promotor of low potency for mouse skin compared to phorbol myristate acetate.

3T3 Cells↗

PubMed1992

Direct effects of medroxyprogesterone acetate, danazol, and leuprolide acetate on endometrial stromal cell proliferation in vitro.

OBJECTIVE: To assess the direct effects of three endometriosis chemotherapeutic agents (medroxyprogesterone acetate [MPA], danazol, and leuprolide acetate [LA]) on endometrial cell proliferation. DESIGN: Analysis of cell proliferation in vitro. SETTING: Proliferative phase endometrial stromal cells isolated from biopsy specimens and grown in short-term culture served as a model for stromal components of endometriotic implants. PATIENTS: Biopsies obtained from volunteers with regular cycles and without endometriosis or endometrial pathology. INTERVENTIONS: Medroxyprogesterone acetate, danazol, and LA were added to nutrient media with the following supplements: 2.5% calf serum (CS) only; 2.5% CS+estradiol (E2) 110 pmol/L; 2.5% CS+E2 550 pmol/L; 10% preovulatory serum (net E2 624 pmol/L). MAIN OUTCOME MEASURES: Cumulative [3H]-thymidine incorporation as a reflection of cell proliferation. RESULTS: Medroxyprogesterone acetate and danazol exerted significant antiproliferative effects on stromal cell proliferation (P less than 0.05), effects that were enhanced by an absence of exogenous E2. Leuprolide acetate exerted no consistent effects. CONCLUSIONS: These data imply that MPA and danazol but not LA exert direct effects, suppressing growth of endometriotic implants.

Adult↗

PubMed1992

A new automated method for phenotyping arylesterase (EC 3.1.1.2) based upon inhibition of enzymatic hydrolysis of 4-nitrophenyl acetate by phenyl acetate.

A new method for phenotyping human serum arylesterase (EC 3.1.1.2) is described and evaluated. The aromatic esters, phenyl acetate and 4-nitrophenyl acetate, were compared as substrates for spectrophotometric measurement of arylesterase activity. A method for arylesterase phenotyping, based upon inhibition of the enzymatic hydrolysis of 4-nitrophenyl acetate by phenyl acetate, was developed. The method was applied to serum samples from 158 blood donors and showed a distinct separation of the three phenotypes defined by a reference method based on the ratio of paraoxonase activity to arylesterase activity using paraoxon and phenyl acetate as substrates. The method was adapted to a Cobas-Fara centrifugal analyser.

Alleles↗

PubMed1992

Granulocyte elastase, beta-thromboglobulin, and C3d during acetate or bicarbonate hemodialysis with Hemophan compared to a cellulose acetate membrane.

Twenty-two patients were dialysed in a cross-over design using Hemophan or cellulose acetate membranes. The dialysate buffer was acetate (n = 12) or bicarbonate (n = 10). Blood was sampled at 0, 15, 60 and 180 min and mean values were adjusted for changes in total protein in each sample. At 15 min during dialysis a decrease in leukocytes and platelets occurred with both membranes, irrespective of the buffer (Wilcoxon, p less than 0.006). During dialysis, increases were found in granulocyte elastase inhibitor complex (E- alpha 1-PI), beta-thromboglobulin and C3d. beta 2-microglobulin was not significantly changed in blood after dialysis with Hemophan or cellulose acetate membranes with bicarbonate buffer. Side effects were more pronounced at 180 min during dialysis with bicarbonate in patients using cellulose acetate than with Hemophan (p = 0.021, n = 8). Hemophan seemed to be more favourable than cellulose acetate membranes in regard to leukopenia and E- alpha 1-PI. The dialysate buffer may also alter membrane biocompatibility.

Biocompatible Materials↗

PubMed1990

Determination of megestrol acetate and cyproterone acetate in serum of patients with advanced breast cancer by high-performance liquid chromatography.

A reversed-phase high-performance liquid chromatographic method with ultraviolet detection of megestrol acetate and cyproterone acetate in human sera is described. The proposed assay is linear up to 1400 ng/ml (r = 0.999) and has a detection limit of 5 ng/ml. Recoveries of both compounds in spiked sera were ca. 95%; inter-assay coefficients of variation were 4.0 and 3.1% and intra-assay values were 1.3 and 1.4%, respectively. For validation of the method we also developed a gas chromatographic-mass spectrometric method for both steroids. The results obtained by the two methods showed good correlation: for megestrol acetate r = 0.98, n = 31, p less than 0.0001, and for cyproterone acetate r = 0.94, n = 0, p less than 0.0001. Large inter-individual differences in the serum concentrations of both substances were found in groups of patients with metastatic breast cancer receiving the same oral load of either steroid.

Antineoplastic Agents↗