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At least 433 records · Page 24Linked to original sources
PubMed1997

Comparison of once daily mometasone furoate (Nasonex) and fluticasone propionate aqueous nasal sprays for the treatment of perennial rhinitis. The 194-079 Study Group.

BACKGROUND: Mometasone furoate (Nasonex), in a new once-daily aqueous nasal spray formulation, has been shown to be as effective and well-tolerated as twice-daily beclomethasone dipropionate aqueous nasal spray in treating symptoms of seasonal allergic rhinitis and perennial rhinitis. OBJECTIVE: To compare the effectiveness and tolerability of mometasone furoate to placebo and to fluticasone propionate aqueous nasal spray, all treatments administered once-daily, in patients with perennial rhinitis. METHODS: This was a 3-month, randomized, double-blind, double dummy, parallel group study in 550 patients, aged 12 to 77 years, at 25 centers in Canada, Latin America, and Europe. Patients allergic to at least one perennial allergen, with confirmed allergy history, skin test positivity, and moderate to severe symptomatology, were eligible to receive one of the following treatments, once daily in the morning: mometasone furoate 200 micrograms, fluticasone propionate 200 micrograms, or placebo. The primary efficacy variable was the change from baseline in total AM plus PM diary nasal symptom score over the first 15 days of treatment. RESULTS: Four hundred fifty-nine patients were valid for efficacy. For the primary efficacy variable, mometasone furoate was significantly (P < .01) more effective than placebo and was not statistically different from fluticasone propionate (percent reductions from baseline were 37, 39, and 22 for mometasone furoate, fluticasone propionate, and placebo, respectively). Generally, similar trends were seen for physician-evaluated total nasal symptoms, and patient-rated and physician-rated overall condition and response to therapy. Overall, mometasone furoate was at least as effective as fluticasone propionate at equivalent doses. There was no evidence of tachyphylaxis. All treatments were well tolerated. CONCLUSION: Mometasone furoate and fluticasone propionate adequately controlled symptoms of perennial rhinitis and were well tolerated.

Administration, Inhalation↗
PubMed2004

Enhanced biological phosphorus removal in a sequencing batch reactor using propionate as the sole carbon source.

An enhanced biological phosphorus removal (EBPR) system was developed in a sequencing batch reactor (SBR) using propionate as the sole carbon source. The microbial community was followed using fluorescence in situ hybridization (FISH) techniques and Candidatus 'Accumulibacter phosphatis' were quantified from the start up of the reactor until steady state. A series of SBR cycle studies was performed when 55% of the SBR biomass was Accumulibacter, a confirmed polyphosphate accumulating organism (PAO) and when Candidatus 'Competibacter phosphatis', a confirmed glycogen-accumulating organism (GAO), was essentially undetectable. These experiments evaluated two different carbon sources (propionate and acetate), and in every case, two different P-release rates were detected. The highest rate took place while there was volatile fatty acid (VFA) in the mixed liquor, and after the VFA was depleted a second P-release rate was observed. This second rate was very similar to the one detected in experiments performed without added VFA.A kinetic and stoichiometric model developed as a modification of Activated Sludge Model 2 (ASM2) including glycogen economy, was fitted to the experimental profiles. The validation and calibration of this model was carried out with the cycle study experiments performed using both VFAs. The effect of pH from 6.5 to 8.0 on anaerobic P-release and VFA-uptake and aerobic P-uptake was also studied using propionate. The optimal overall working pH was around 7.5. This is the first study of the microbial community involved in EBPR developed with propionate as a sole carbon source along with detailed process performance investigations of the propionate-utilizing PAOs.

Acetate-CoA Ligase↗
PubMedDate not supplied

Propionate inhibits glucose-induced insulin secretion in isolated rat pancreatic islets.

Dietary fibers, probably by generating short chain fatty acids (SCFA) through enterobacterial fermentation, have a beneficial effect on the control of glycemia in patients with peripheral insulin resistance. We studied the effect of propionate on glucose-induced insulin secretion in isolated rat pancreatic islets. Evidence is presented that propionate, one of the major SCFA produced in the gut, inhibits insulin secretion induced by high glucose concentrations (11.1 and 16.7 mM) in incubated and perfused pancreatic islets. This short chain fatty acid reduces [U-(14)C]-glucose decarboxylation and raises the conversion of glucose to lactate. Propionate causes a significant decrease of both [1-(14)C]- (84%) and [2-(14)C]-pyruvate (49%) decarboxylation. These findings indicate pyruvate dehydrogenase as the major site for the propionate effect. These observations led us to postulate that the reduction in glucose oxidation and the consequent decrease in the ATP/ADP ratio may be the major mechanism for the lower insulin secretion to glucose stimulus induced by propionate.

Adenosine Diphosphate↗
PubMed1981

Propionate formation in Rhodospirillum rubrum under anaerobic dark conditions.

Experiments with 14C labelled propionyl-CoA, methylmalonyl-CoA and succinyl-CoA showed that these compounds are intermediates of propionate synthesis in fermentative metabolism of Rhodospirillum rubrum. The rate of propionate and succinate production is dependent on the CO2 concentration of the medium. There is, however, no evidence for a transcarboxylation, and high concentrations of propionate in the medium did not inhibit propionate synthesis as in the case in propionibacteria. PEP-carboxykinase (EC 4.1.1.32) and propionyl-CoA-carboxylase (EC 6.4.1.3) showed high activities, whereas the other two PEP-carboxylases (EC 4.1.1.31, EC 4.1.1.38), and the pyruvate-carboxylase (EC 4.1.1.1.) showed only very low activity. It is probable that in pyruvate fermentation metabolism of R. rubrum no specific enzymes are activated for propionate formation and all enzymes are still present from aerobic or phototrophic preculture.

Anaerobiosis↗
PubMed1991

Effects of propionate on mechanical and metabolic performance in aerobic rat hearts.

The purpose of this report is to describe the contribution of propionate as an adjunct source of oxidative metabolism in aerobic myocardium. In the first series of studies, six groups of isolated working rat hearts (n = 6-8 per group) were perfused for 40 minutes with Krebs-Henseleit media containing 11 mM glucose. Propionate treatment was provided to the media at a constant dose per heart group and extended over a range of dosages, including: 0 (placebo control), 0.1, 0.5, 1.0, 5.0, and 10.0 mM, buffered to pH 7.4. Average aerobic coronary blood flow for all groups was 21.5 +/- 0.6 ml/min; average left ventricular peak systolic pressure was 123.7 +/- 1.4 mmHg. There were no significant differences among groups compared with placebo hearts for aortic flow, heart rate x aortic pressure product, or myocardial oxygen consumption, although performance tended to decline in the 10 mM group. A clear dose-response relationship was observed in 14CO2 production from labeled propionate, with a 12-fold increase between the 0.1 and 10 mM groups. Most of the increase occurred at the lower dosages, with a relative leveling off at the 1.0, 5.0, and 10.0 mM doses. In part 2, propionate was examined as a sole substrate. At 1.0 mM without glucose, propionate per se was unable to support mechanical function over the course of the perfusions, but still maintained high rates of oxidation, comparable to that of the 1.0 mM group with glucose in part 1.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Sequential changes in propionate metabolism during the development of cobalt/vitamin B12 deficiency in sheep.

The changes in propionate metabolism that accompany cobalt deficiency in sheep are described. Two groups of sheep, fed either a cobalt sufficient or deficient diet, were given an iv propionate load at intervals during a 14 w experiment. There was a tendency towards increased propionate half-life as the animals became cobalt deficient. However, significant changes in the area under the plasma methylmalonic acid-time curve occurred very early, indicating significant impairment of propionate metabolism. Despite this, the area under the plasma glucose-time curve was unaffected by cobalt deficiency, suggesting that the impairment of propionate metabolism, although significant, is not extensive.

Animals↗
PubMed1997

Stable isotope studies in propionic and methylmalonic acidaemia.

Stable isotope techniques have been used to measure propionate production and disposal in patients with propionic and methylmalonic acidaemia. There are wide variations between individual patients but aminoacid catabolism accounts for approximately 50% of propionate production, bacterial activity in the gut 25% and catabolism of odd chain fatty acids 25%. Oxidation of propionate is an important route of disposal. These studies have helped to improve the management of inborn errors of propionate metabolism.

Amino Acid Metabolism, Inborn Errors↗
PubMed1985

The role for butyrate and propionate in mediating HeLa-cells growth inhibition by human dental plaque fluid from adult periodontal disease.

To determine to what extent propionate and butyrate, secreted in vitro by various oral bacteria, account for the growth-inhibiting activity of plaque fluid in gingivitis in the absence or presence of chronic periodontitis, the fluid phase of plaque from each of these disease forms was obtained by homogenizing the bacteria with 0.13 M NaCl, centrifuging the mixture and Millipore-filter-sterilizing the plaque-fluid-extract supernatant. Toxins were detected and measured by growth inhibition of HeLa cells grown in minimal Eagle medium supplemented with calf serum and antibiotics. Samples of butyrate, propionate or plaque-fluid extract were added and inhibition of growth was determined relative to control cultures. The toxins in each extract were characterized by their stability to heat, freeze-drying and elution on gel filtration. Butyrate and propionate contents were measured with a Hewlett-Packard 5880A gas chromatograph. The plaque-fluid extracts from each group had similar contents of butyrate, but most of the activity was due to heat-sensitive high mol. wt components. Butyrate and propionate accounted for only 5 to 15 per cent of the total activity. High mol. wt exotoxins, rather than butyrate or propionate, were the most prominent and freeze-drying-stable tissue-destructive agents in the plaque fluid from subjects with or without periodontitis.

Acetates↗
PubMed1975

On the effects of propionate and other short-chain fatty acids on sodium transport by the toad bladder.

1. Propionate and other unbranched short-chain fatty acids, butyrate, pentanoate, hexanoate and octanoate were found to both stimulate and inhibit active sodium transport by the toad bladder, as measured by the short-circuit current (s.c.c.). 2. Stimulation alone followed addition of low concentrations of fatty acids (0.1-1.0 mM) to either the serosal or mucosal bathing medium; stimulation was also seen after an initial period of inhibition in response to higher concentrations (approx. 5 mM) of some compounds. 3. Inhibition alone followed addition of high concentrations (5-20 mM) of these compounds. The duration and magnitude of the inhibition varied with increasing concentration and chain length of the fatty acid, and was greater following mucosal addition than serosal addition. 4. The inhibitory effect of mucosal propionate increased with decreasing pH of the mucosal bathing medium. 5. Inhibition by the fatty acids was completely reversed upon removing the compound from the bathing medium, and stimulation characteristically followed. 6. In studies designed to evaluate the role of metabolism of the fatty acids in their mucosal inhibitory effects it was found that 14-c-labelled propionate, when added to the mucosal surface of the bladder, was converted to 14-CO2, and mucosal succinate and alpha-oxoglutaric acid at 20 mM inhibited the s.c.c. slightly. However, malonate did not interfere with inhibition by mucosal propionate and two non-metabolizable acids, dimethylpropionate and benzoate, induced inhibition (and no stimulation) of the s.c.c. 7. In the presence of an inhibitory concentration of fatty acid, the ability of the bladder to respond to added pyruvate was reduced in proportion to the reduction in the level of the s.c.c., whereas the natriferic response to vasopressin was largely intact. 8. We conclude that stimulation of sodium transport by propionate and other short-chain fatty acids is due to metabolism of the compounds and provision of energy to the sodium transport mechanism. The basis of the inhibition appears complex. It may in part depend on metabolism of the fatty acids and/or uncoupling of oxidative phosphorylation, with resultant reduction in net ATP production for the sodium transport mechanism. However, the inhibition may also be caused in part by a direct effect on the mucosal entry of sodium into the transporting epithelial cells.

Animals↗
PubMed1993

Propionate regulates lymphocyte proliferation and metabolism.

1. The effect of propionate on lymphocyte proliferation and metabolism was investigated. Lymphocytes obtained from human blood and rat mesenteric lymph nodes were utilized. 2. Propionate at concentrations of 0.04 and 1.0 mmol/l stimulated the amount of [3H]thymidine incorporated either in cultured human T lymphocytes or rat T and B lymphocytes. 3. Concentrations of propionate between 2 and 5 mmol/l caused a marked inhibition of lymphocyte proliferation. 4. This short-chain fatty acid was metabolized by these cells and produced succinate in significant amounts; however, its oxidation was low. 5. Propionate did not alter glucose, glutamine and pyruvate utilization and oxidation in incubated rat lymphocytes but increased the formation of lactate and aspartate. 6. In contrast, propionate inhibited by 50% the synthesis of lymphocyte lipid from [1-14C]acetate at concentrations of 0.5 and 1 mmol/l and reduced by half the incorporation of 3H2O into lipids at 1 and 5 mmol/l. 7. The results suggest that inhibition of lipid synthesis is a possible mechanism leading to reduction of lymphocytes proliferation.

Adult↗
PubMed1995

Propionate modifies lipid biosynthesis in rat peritoneal macrophages.

1. This study examines the effect of propionate, normally produced in the gut, on lipid metabolism of resident macrophage. This cell is very abundant in the epithelial lining of the gut. 2. The activity of propionyl-CoA synthetase in macrophages was shown to be 0.39 nmol/min per mg protein, so this cell presents the ability to use propionate. Propionate at concentrations varying from 0.5 to 5 mM did not affect the activities of carnitine acetyltransferase, ATP-citrate lyase, acetoacetyl-CoA thiolase and 3-oxoacid-CoA transferase. 3. Thus this short chain fatty acid did not alter the capacity for transferring acetyl-CoA from mitochondria to cytosol and for ketone bodies formation and oxidation. However, propionate (40 mM) inhibited the incorporation of [1-14C]-palmitate into phospholipids, cholesterol, cholesterol ester and triacylglycerol and the incorporation of [3-14C]-pyruvate into phospholipids. 4. These findings suggest that fibre-rich diet by generating propionate may regulate macrophage lipid metabolism.

ATP Citrate (pro-S)-Lyase↗
PubMed1991

The effect of malate on propionate mitochondrial toxicity.

Propionic acidemia occasionally produces a toxic encephalopathy resembling Reye's syndrome, indicating disruption of mitochondrial metabolism. Liver mitochondria respiratory control ratios were reduced 46% by 5 mM propionate; inhibition correlated with matrix propionyl-CoA levels. L-Malate prevented the toxic effect of propionate and reduced the propionyl-CoA matrix concentration by 62%. The beneficial effect of L-malate is apparently due to stimulation of succinate efflux because the effect is blocked by benzylmalonate, an inhibitor of the dicarboxylate carrier. Matrix concentration of label from [1-14C]propionate was not affected by L-malate and/or benzylmalonate. L-Malate may be useful in the treatment of patients with propionic acidemia.

Acyl Coenzyme A↗
PubMed2006

Propionate induces pH(i) changes through calcium flux, ERK1/2, p38, and PKC in bovine neutrophils.

Propionate is a short-chain fatty acid produced under normal physiological conditions in the rumen of cattle. It is also involved in the inflammatory process and neutrophil function via calcium release, reactive oxygen species and intracellular pH (pH(i)) changes. This study examined the effect of propionate on the pH(i) of bovine neutrophils; specifically if pH(i) changes are controlled by calcium flux, and the mitogen-activated protein kinase (MAPK) pathway. Propionate caused rapid intracellular acidification and sustained alkalinization in bovine neutrophils loaded with 2',7'-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein acetoxymethyl ester (BCECF-AM), a fluorescent indicator of pH(i). The acidification phase seems to be controlled by intracellular calcium release and p38 MAPK pathway. The pH recovery phenomenon was mediated by an amiloride-sensitive Na+/H+ exchanger and H+ channel, and was inhibited by UO126 (an ERK1/2 MAPK phosphorylation inhibitor), Gö6850 (a PKC inhibitor) and calcium chelating. Ionomycin, a calcium ionophore, induced intracellular acidification and sustained alkalinization. The intracellular acidification was strongly inhibited by BAPTA-AM (an intracellular calcium chelator) and SB203580 (a p38 MAPK inhibitor). In addition, the intracellular alkalinization was reduced by EGTA (a calcium chelator), UO126, LY294002 (a PI3K inhibitor) and Gö6850. Propionate did not increase superoxide production, however it reduced the superoxide production induced by platelet-activating factor (PAF), and increased the release of superoxide induced by ionomycin. Our results suggest that propionate-induced intracellular acidification is mediated by intracellular calcium release and p38 MAPK activation, and that pH recovery is controlled via ERK1/2 MAPK, PKC and calcium entry in bovine neutrophils.

Animals↗
PubMed2002

Propionic acid side chain hydrogen bonding in the malaria pigment beta-hematin.

Malaria pigment, or beta-hematin, the insoluble heme detoxification product resulting from the intraerythrocitic digestion of hemoglobin by young malaria trophozoites has been structurally characterized by X-ray powder diffraction and shown to contain chains of propionic acid linked dimers. Although there is considerable spectroscopic evidence for a monodentate propionate-iron interaction in this crystalline material, the spectroscopic characterization of the propionic acid dimer is limited. Herein we demonstrate the presence of the propionic acid dimer unit by H/D isotope substitution in carboxylic acid dimer. In the Raman spectrum of the deuterium substituted compound there is a circa 12 cm(-1) shift, H: 1629 cm(-1) vs. D: 1617 cm(-1) in the symmetric ring breathing mode for the propionic acid dimer. On the other hand, the IR active asymmetric stretch has a very small shift, <3 cm(-1), upon deuteration. These, and other vibrational data, are consistent with the presence of a planar carboxylic acid dimer in the structure of beta-hematin.

Animals↗
PubMed1997

Ethyl propionate is more effective and less cytotoxic than methyl tert-butyl ether for topical gallstone dissolution.

BACKGROUND & AIMS: Ethyl propionate and isopropyl acetate were identified as gallstone solvents with more favorable physicochemical properties than the currently used solvent methyl tert-butyl ether (MTBE). In this study, their efficacy and toxicity were compared. METHODS: To compare efficacy, matched stones from 33 patients were subjected to dissolution with each solvent. To evaluate cytotoxicity, jejunal segments of the anesthetized rat were exposed to each solvent or saline; the segments were then perfused with markers for active absorption and passive permeability. RESULTS: For 23 gallstone sets that dissolved completely with all three solvents, the average dissolution time was shorter with ethyl propionate (38 +/- 8 minutes) than with MTBE (60 +/- 13 minutes) (P = 0.03) or isopropyl acetate (55 +/- 12 minutes) (P < 0.001). Four stones did not dissolve with ethyl propionate, seven with MTBE, and eight with isopropyl acetate. After 2 minutes of exposure to the solvents, the dry weight of the segments decreased by 36% after MTBE but was unchanged after the other two solvents (P < 0.001). MTBE caused more inhibition of active absorption than the other solvents (P < 0.001) and a greater increase in passive permeation (P < 0.03). CONCLUSIONS: Ethyl propionate and isopropyl acetate are less toxic to the intestinal mucosa than MTBE, and ethyl propionate is more effective for gallstone dissolution.

Acetates↗
PubMed2002

Ascorbic acid prevents cognitive deficits caused by chronic administration of propionic acid to rats in the water maze.

Propionic acidemia is an inherited neurometabolic disorder characterized by progressive neurological deterioration with psychomotor delay/mental retardation, convulsions and coma, and whose pathophysiology is poorly unknown. In the present study, we investigated the effect of chronic administration (from the 5th to the 28th days of life) of propionic acid (PA), the major metabolite accumulating in tissues of patients affected by propionic acidemia, on the cognitive performance of adult rats in the Morris water maze task. PA doses ranged from 1.44 to 1.92 micromol/g body weight as a function of animal age. Control rats were treated with saline in the same volumes. Chronic postnatal days (5-28) PA treatment had no effect on body weight. However, it impaired spatial performance in the water maze. We also determined the effect of ascorbic acid (AA) administered, alone or combined with PA, on the same behavioral parameters in order to test whether free radicals could be responsible for the behavioral alterations observed in PA-treated animals. AA was able to prevent the behavioral alterations provoked by PA, implying that oxidative stress may be involved in these effects. Furthermore, we also investigated the total radical-trapping antioxidant potential (TRAP) in the hippocampus of the animals. We observed that TRAP was significantly reduced in the brain of propionic acidemic rats and that co-administration of AA prevented this effect. The results provide evidence that early PA treatment induces long-lasting behavioral deficits, which are possibly caused by oxygen reactive species generation, and suggest that oxidative stress may be involved in the neuropathology of propionic acidemia.

Animals↗
PubMed2001

In vitro conversion of propionate to pyruvate by Salmonella enterica enzymes: 2-methylcitrate dehydratase (PrpD) and aconitase Enzymes catalyze the conversion of 2-methylcitrate to 2-methylisocitrate.

Salmonella enterica serovar Typhimurium LT2 catabolizes propionate through the 2-methylcitric acid cycle, but the identity of the enzymes catalyzing the conversion of 2-methylcitrate into 2-methylisocitrate is unclear. This work shows that the prpD gene of the prpBCDE operon of this bacterium encodes a protein with 2-methylcitrate dehydratase enzyme activity. Homogeneous PrpD enzyme did not contain an iron-sulfur center, displayed no requirements for metal cations or reducing agents for activity, and did not catalyze the hydration of 2-methyl-cis-aconitate to 2-methylisocitrate. It was concluded that the gene encoding the 2-methyl-cis-aconitate hydratase enzyme is encoded outside the prpBCDE operon. Computer analysis of bacterial genome databases identified the presence of orthologues of the acnA gene (encodes aconitase A) in a number of putative prp operons. Homogeneous AcnA protein of S. enterica had strong aconitase activity and catalyzed the hydration of the 2-methyl-cis-aconitate to yield 2-methylisocitrate. The purification of this enzyme allows the complete reconstitution of the 2-methylcitric acid cycle in vitro using homogeneous preparations of the PrpE, PrpC, PrpD, AcnA, and PrpB enzymes. However, inactivation of the acnA gene did not block growth of S. enterica on propionate as carbon and energy source. The existence of a redundant aconitase activity (encoded by acnB) was postulated to be responsible for the lack of a phenotype in acnA mutant strains. Consistent with this hypothesis, homogeneous AcnB protein of S. enterica also had strong aconitase activity and catalyzed the conversion of 2-methyl-cis-aconitate into 2-methylisocitrate. To address the involvement of AcnB in propionate catabolism, an acnA and acnB double mutant was constructed, and this mutant strain cannot grow on propionate even when supplemented with glutamate. The phenotype of this double mutant indicates that the aconitase enzymes are required for the 2-methylcitric acid cycle during propionate catabolism.

Aconitate Hydratase↗
PubMed2000

Functional properties of the heme propionates in cytochrome c oxidase from Paracoccus denitrificans. Evidence from FTIR difference spectroscopy and site-directed mutagenesis.

By specific (13)C labeling of the heme propionates, four bands in the reduced-minus-oxidized FTIR difference spectrum of cytochrome c oxidase from Paracoccus denitrificans have been assigned to the heme propionates [Behr, J., Hellwig, P., Mäntele, W., and Michel, H. (1998) Biochemistry 37, 7400-7406]. To attribute these signals to the individual propionates, we have constructed seven cytochrome coxidase variants using site-directed mutagenesis of subunit I. The mutant enzymes W87Y, W87F, W164F, H403A, Y406F, R473K, and R474K were characterized by measurement of enzymatic turnover, proton pumping activity, and Vis and FTIR spectroscopy. Whereas the mutant enzymes W164F and Y406F were found to be structurally altered, the other cytochrome c oxidase variants were suitable for band assignment in the infrared. Reduced-minus-oxidized FTIR difference spectra of the mutant enzymes were used to identify the ring D propionate of heme a as a likely proton acceptor upon reduction of cytochromic oxidase. The ring D propionate of heme a(3) might undergo conformational changes or, less likely, act as a proton donor.

Amino Acid Substitution↗