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PubMed1994

Urinary excretion of homocitric acid and methylhomocitric acid in propionic acidaemia: minor metabolic products of the citrate synthase aldol condensation reaction.

The identity of two formerly novel citric acid analogues, homocitric acid and methylhomocitric acid, in urine samples from patients with propionic acidaemia was confirmed by gas chromatography and mass spectrometry. Authentic reference substances were synthesized using a Reformatskii reaction. Homocitric acid and methylhomocitric acid were detected as minor metabolites in the urine samples from propionyl coenzyme A carboxylase deficient individuals. It was shown that these substances can be formed by the citrate synthase condensation reaction of alpha-ketoglutarate with acetyl coenzyme A and propionyl coenzyme A, respectively.

Acidosis↗
PubMed1978

A possible mechanism of choleretic action of 3-(2,4,5-triethoxybenzoyl)-propionic acid (AA-149) in dogs.

The choleretic action of 3-(2,4,5-triethoxybenzoyl)propionic acid (AA-149) was studied in anesthetized dogs. AA-149 produced a dose-dependent increase of the bile flow with both i.v. and intrajejunal administration of doses 1 mg/kg and higher. Biliary clearance of 14C-erythritol showed that AA-149 stimulated canalicular bile formation without enhancement of water secretion and/or inhibition of bile reabsorption in the biliary ductules and ducts. AA-149 did not increase the excretion of bile acids into the bile, but enhanced the excretion of the biliary electrolytes, in particular sodium ion, in proportion to an increase of the bile flow. About 3--4% of AA-149 administered i.v. was excreted into the bile during the first 1 h period, so that biliary AA-149 was insufficient to increase the bile flow via its osmotic effect. These results strongly suggest that the choleretic action of AA-149 is attributable to stimulation of a bile acid-independent bile formation in the canaliculi coupled with an active sodium transport system.

Animals↗
PubMed1978

Biliary spasmolytic action of 3-(2,4,5-triethoxybenzoyl)propionic acid (AA-149) in dogs.

The spasmolytic action of 3-(2,4,5-triethoxybenzoyl)propionic acid (AA-149) on the biliary tract was investigated in anesthetized dogs. Intravenous administration of AA-149 at 2 mg/kg and higher doses produced a dose-dependent reduction in passage resistance through the choledochoduodenal junction and in gallbladder pressure, and a dose-dependent increase in bile flow. AA-149, like cholecystokinin, decreased biliary ductal pressure in spite of increasing the bile flow in dogs with ligation of the cystic duct of the gallbladder, whereas taurocholate increased the pressure as well as the bile flow. Moreover, the spasmic response of the choledochoduodenal junction to morphine was depressed strongly by AA-149, BUT NOT CONSISTENTLY BY ATROPINE. The effects of AA-149 were not influenced by pretreatment with atropine, phentolamine or propranolol. These findings strongly suggest that AA-149 relaxed the biliary tract and depressed the morphine-induced spasm by a mechanism different from those of anticholinergic and sympathomimetic agents.

Animals↗
PubMed1989

Hypoxic pulmonary vasoconstriction is unaltered by creatine depletion induced by dietary beta-guanidino propionic acid.

It has been suggested that a specific phosphagen pool might serve a sensor function, allowing direct detection of alveolar hypoxia by the pulmonary vascular smooth muscle. The possibility that phosphocreatine (PCr) levels could serve as such a sensor was assessed in isolated rat lungs. Pulmonary vascular reactivity to angiotensin II and alveolar hypoxia was assessed in lungs from control and PCr-depleted rats. PCr depletion was accomplished by feeding rats a diet containing 2% beta-guanidino propionic acid (beta-GPA), an competitive inhibitor of creatine uptake. Total creatine was depleted in beta-GPA lungs, compared to control lungs (p less than 0.05). Lung PCr levels were undetectable by the available 31P NMR spectroscopy system. PCr and creatine were depleted in hearts from beta-GPA rats relative to control hearts (p less than 0.001). Normoxic pulmonary artery pressure and the pressor responses to angiotensin II and hypoxia were not qualitatively or quantitatively altered by the diet indicating either that PCr is not a critical participant in hypoxic pulmonary vasoconstriction or that the degree of PCr depletion achieved was inadequate to expose its role in the hypoxic pressor response.

Animals↗
PubMed1989

High resolution of honey bee (Apis mellifera) venom peptides by propionic acid/urea polyacrylamide gel electrophoresis after ethanol precipitation.

A new and simple gel electrophoretic method is described which enables the protein and polypeptide components of bee venom to be resolved on a single gel. The electrophoretic method allows octapeptides to be resolved and species as small as decapeptides can be detected at high sensitivity using the Coomassie blue staining method without prior fixation. This has been achieved by replacing acetic acid by propionic acid in acid/urea polyacrylamide gels and by controlling the amount of TEMED catalyst for the polymerisation of high concentration gels in order to obtain a low effective pore size. We demonstrated the value of ethanol precipitation as a rapid and efficient desalting the fractionation technique and propose that it could be used in combination with gel filtration to purify many of the peptides to homogeneity.

Animals↗
PubMed1993

Mechanisms of the secretory response to luminal propionate in rat descending colon in vitro.

Short chain fatty acids stimulate Cl secretion in rat descending colon in vitro via an enteric reflex involving mucosa and cholinergic nerves. We used the short circuit current as the measure of Cl secretion caused by Na propionate (NaP) (0.5 mM) in luminal bath fluid and studied the mechanism of the response. The NaP response was decreased 81% by atropine and 76% by lidocaine. It was unaffected by tetrodotoxin, omega-conotoxin or by tachyphylaxis to capsaicin, CGRP, substance P, histamine or PGE2. It was not reduced by inhibitors of 5-HT2 or 5HT3 receptors or by partial tachyphylaxis to 5-HT. However, superficial mucosal injury with hypertonic Na sulfate (2 M) or xylose (4.5 M) reduced the NaP response by 90% and 86%, respectively, and mucosal concanavalin A (1 mg/ml) reduced it by 73%. Neither piroxicam (10 microM) nor nordihydroguaretic acid (10 microM) affected the NaP response. We hypothesize that NaP stimulates the superficial epithelium to release an unidentified agonist that depolarizes predominantly cholinergic nerve terminals and causes colonic secretion.

Acetylcholine↗
PubMed1981

Succinate decarboxylation to propionate and the associated phosphorylation in Fasciola hepatica and Spirometra mansonoides.

The trematode, Fasciola hepatica, and the cestode, Spirometra mansonoides have been shown to be similar to the nematode Ascaris lumbricoides in that all three decarboxylate succinate to propionate plus CO2. Associated with this decarboxylation is an incorporation of 32Pi into organic phosphate. Both the decarboxylation and phosphorylation are markedly stimulated by the addition of propionyl-CoA, are dependent on coenzyme B12 and are inhibited by avidin. The trematode and cestode exhibit propionyl-CoA carboxylase, methylmalonyl-CoA mutase and acyl-CoA transferase activities in sonicated mitochondrial preparations. Data are consistent with the occurrence of a mitochondrial substrate level site for ATP generation which is coupled with the decarboxylation of succinate. In Fasciola preparations, acetyl-CoA stimulates the decarboxylation and phosphorylation to a considerably larger extent than propionyl-CoA, indicating the possibility that acetyl-CoA may serve physiologically in these reactions by donating the CoA moiety to succinate.

Acetyl Coenzyme A↗
PubMed1992

Propionic acid and the phenomenon of rodent forestomach tumorigenesis: a review.

Propionic acid (PA) is widely used as an antifungal agent in food. It is present naturally at low levels in dairy products and occurs ubiquitously, together with other short-chain fatty acids (SCFA), in the gastro-intestinal tract of humans and other mammals as an end-product of the microbial digestion of carbohydrates. It has significant physiological activity in animals. PA is irritant but produces no acute systemic effects and has no demonstrable genotoxic potential. Rats receiving PA at 4% in the diet develop hyperplastic lesions and tumours of the forestomach. Such changes are also reported to have been produced by a variety of other chemicals, mechanical and chemical irritants, parasites, and even various dietary insufficiencies or imbalances. Evidence suggests that repeated or persistent damage to cells of the forestomach epithelium and associated proliferative responses may be a common factor in rodent forestomach tumorigenesis. Although humans do not have a forestomach, the mouth, pharynx and oesophagus are lined with similar epithelium and thus are potential target organs. However, food contact time is considerably less in these organs than in the rodent forestomach. On current evidence, PA cannot be considered a carcinogenic risk to humans; nevertheless, to determine a safe level of dietary exposure it is suggested that no-observable-effect levels should be determined for epithelial cell damage and proliferative responses in the squamous mucosa of laboratory animals, particularly in those parts of the gastro-intestinal tract having a counterpart in humans, such as the pharynx and oesophagus.

Animals↗
PubMed1993

Factors affecting the distribution of ingested propionic acid in the rat forestomach.

Propionic acid (PA) when incorporated into food pellets and fed to male Wistar rats for 20 wk had no effect on the forestomach mucosa; however, in powdered diet PA led to pronounced hyperplasia and severe inflammatory lesions in the forestomach mucosa near the limiting ridge. Since this discrepancy in the effect of PA may have been caused by the type of diet in which PA was administered, the distribution of total PA (including the corresponding acid-soluble CoA ester) in different parts of the stomach and certain variables affecting this distribution were investigated. In the forestomachs of rats fed 4% PA in powdered diet, the amount of PA in hyperplasias (1553 +/- 508 micrograms PA/g tissue) was three times higher than that in the remainder of the tissue (479 +/- 247 micrograms PA/g tissue). The PA content decreased progressively towards the glandular parts. There was a slight, but not significant, decrease in the PA content of the forestomach and a slight increase in the PA content of the glandular stomach in rats fed pelleted food compared with those fed powdered diet. Supplementation of 1% L-carnitine to PA powdered diet for 12 wk led to a significant decrease (P < 0.02) in PA accumulation in hyperplastic tissues compared with hyperplasias induced by PA alone, although L-carnitine had no influence on the severity of hyperplastic changes in the forestomachs of rats. The present study shows that the type of diet in which PA was administered to male Wistar rats is of great importance for the development of hyperplasia, PA or the corresponding CoA ester can accumulate in the forestomach and is preferably accumulated in hyperplasias, and PA accumulation does not appear to be directly related to the severity of hyperplastic changes.

Administration, Oral↗
PubMed1983

Limitations to the usefulness of N-succinimidyl propionate for the study of retrograde axonal transport.

Retrograde axonal transport of radiolabelled proteins was studied in rat sciatic nerve, after direct application of [3H]N-succinimidyl propionate. Waves of radiolabelled proteins were observed but only two proteins were predominantly labelled, one of molecular weight 68 kilodaltons (K) and the other of 19K. There was no evidence to confirm the waves as representing retrograde axonal transport of identifiable proteins, and the tendency of the covalent label to bind selectively in vivo to a small number of prominent proteins limits its usefulness for the detection of retrogradely transported proteins in general.

Animals↗
PubMed1983

Potassium propionate causes preferential loss of 'bound' acetylcholine in frog muscle.

Bound and free acetylcholine (ACh) were measured in frog sartorius muscles by mass fragmentography. Upon incubation of the muscles for 5 min with potassium propionate, which stimulated the release of ACh, there was a 2-fold reduction of bound ACh. In contrast, the amount of free ACh remained unchanged. After 65 min recovery from stimulation in normal Ringer solution containing deuterium-labelled choline, free ACh was labelled to a higher degree than bound ACh. The results are in agreement with the idea that ACh is synthesized in the cytoplasmic compartment of the motor nerve terminal, and subsequently transferred to the vesicles from which it is released upon stimulation.

Acetylcholine↗
PubMed1990

Pyruvate sparing by butyrate and propionate in proliferating colonic epithelium.

1. The effects of fasting and fasting followed by refeeding on the relative activities of the pyruvate dehydrogenase (PDH) complex and the tricarboxylic acid (TCA) cycle in isolated rat colonocytes were estimated by the rate of production of 14CO2 from [1-14C]pyruvate and [3-14C]pyruvate, respectively. 2. Decarboxylation of pyruvate by the PDH complex exceeded that by the TCA cycle in both fasted and fasted/refed colonocytes, was higher in distal than in proximal colon, and was stimulated by refeeding following a fast. 3. Oxidation of pyruvate by both the PDH complex and the TCA cycle was inhibited by butyrate. 4. Propionate alone had no effect, but synergized with butyrate to further reduce pyruvate decarboxylation by the TCA cycle. 5. Preferential utilization of butyrate by proliferating colonic epithelial cells is postulated to maximize the energy yield and spare pyruvate and its precursors for alternative synthetic roles necessary for active cell division.

Animals↗
PubMed1996

Fractionation of wheat proteins by counter-current distribution using aqueous two-phase systems containing propionic acid.

Wheat proteins, soluble in diluted acid (glutenins), have been fractionated by counter-current distribution (CCD) using an aqueous two-phase system. The phase system is based on poly(ethylene glycol) and dextran but contains also 1% propionic acid and 6 mM magnesium sulfate. Approximately half of the bulk proteins partitioned to the upper phase while starch and other particles were recovered only into the lower phase. Whole wheat flour could be applied as sample for the CCD and 57 transfers were carried out. Starch and insoluble proteins remained stationary, while proteins followed the mobile phase to various degrees giving rise to a distribution pattern. The CCD pattern of the proteins showed distinct differences when various kinds of wheat flour were analysed. The patterns indicate that at least six subpopulations of proteins can be obtained by using two-phase extraction.

Acids↗
PubMed1994

Unusual presentations of propionic acidemia.

The files of 25 patients with propionic acidemia (PA), followed by the Inborn Errors of Metabolism Service (IEMS) at King Faisal Specialist Hospital and Research Centre (KFSH & RC) from 1990 to 1993, were studied retrospectively. In 14 patients PA presented acutely with acidosis, hyperammonemia and thrombocytopenia, while in 11 patients the presentation of the disease was unusual. In the latter group, two neonates with PA initially appeared as a primarily hyperammonemic metabolic disease. In two other neonates the vomiting was so severe that they were diagnosed as intestinal obstruction in referral hospitals. The presentation in three infants was primarily as an immune disorder. In four infants, PA appeared as an acute or chronic encephalopathy, i.e. as a silent organic acidemia, with few other findings of the disease. The clinical picture of PA includes facial and nipple dysmorphia, severe hypotonia and vomiting. Severe thrombocytopenia is the hallmark of the metabolic crisis. In one patient it was noticed late and caused intracranial hemorrhage, while in three others intracranial bleeding caused death. The prognosis in PA remained grave despite rigorous treatment. Only seven of the 25 PA patients remained to have a normal life-style, while eight patients expired. The diagnosis is readily achieved by urine gas chromatography/mass spectrometry (GC/MS), by tandem mass spectrometry (MS/MS), or by enzyme analysis of fibroblasts. While there may be both examiner- and patient-related reasons for the variations in the presentation of PA, one other reason may be the heterogeneity of the molecular defect in propionyl-CoA carboxylase.

Abnormalities, Multiple↗
PubMed1994

A study of the response to protein-modified diets for propionic acidemia in twelve patients.

The charts of twelve patients with propionic acidemia (PA) were analyzed retrospectively for the outcome of dietary treatment. The diet was prescribed for each patient based on their individual needs. We established good diet compliance in four PA patients who were alive and well with healthy life-styles at the time of this report. The main difficulty causing non-compliance was the parents' inability to take care of the patient due to other family responsibilities. In two cases, the parents believed their children to be cured and they abandoned diet and medications, resulting in the sudden death of both children. In four cases, the parents were unable to cope with the demands of the diet and medications, while complications and severe classic PA provided no hope for two patients.

Amino Acids↗
PubMed1994

Emergency presentations of patients with methylmalonic acidemia, propionic acidemia and branched chain amino acidemia (MSUD).

The charts of 16 patients with branched chain amino acidemia (MSUD) who had 48 emergency room (ER) visits, of 10 patients with propionic acidemia (PA) who had 57 ER visit, and of 13 patients with methylmalonic acidemia (MMA) who had 154 ER visits, were reviewed retrospectively for the most common clinical presentations, physical and laboratory findings. The most common clinical presentation was acute or chronic vomiting and the most common physical finding was dehydration. When hypoglycemia was found, the mental status of 55% of patients with MSUD and MMA and 20% of patients with PA, was alert. Mixed acid/base disturbance, i.e. alkalosis caused by vomiting mixed with metabolic acidosis caused by the disease, was present in 30% of MSUD, in 33% of PA, and 45% of MMA. There was no relationship between acidosis detected by the blood pH and mental status of the patients. A good correlation between base excess < -5 and serum bicarbonate < 21 mmol/l was found. Blood cultures were positive for bacteria and fungi in 15% of the visits with MSUD, in 23% with PA, and 3% with MMA. Patients with positive blood cultures did not necessarily have a temperature > 39 degrees C nor hypothermia. The results suggest that the mental status of the patients should not detract the ER physician from obtaining blood pH, gases and glucose and in all instances a blood culture should be secured, even if the patient has no fever.

Amino Acid Metabolism, Inborn Errors↗
PubMedDate not supplied

Neurologic outcome of propionic acidemia.

Twenty patients with propionic acidemia were reviewed retrospectively. Two groups were identified: those who presented in the first week of life (11 patients) or after the neonatal period (9 patients). The early onset of disease had a much higher death rate (hazard ratio: 7.52) and all patients in this group were mentally retarded (IQ < or = 60). Movement disorder was common in both groups. Of the early-onset group, 3 patients had mild chorea or dystonia. Four in the late-onset group had a severe movement disorder. In the late onset group, cranial computed tomography disclosed transient basal ganglia lucencies following an episode of metabolic decompensation; however, no disturbance in amine neurotransmitter metabolite concentrations were found in the cerebrospinal fluid.

Amino Acid Metabolism, Inborn Errors↗
PubMed2006

Neurobiological effects of intraventricular propionic acid in rats: possible role of short chain fatty acids on the pathogenesis and characteristics of autism spectrum disorders.

Clinical observations suggest that certain gut and dietary factors may transiently worsen symptoms in autism spectrum disorders (ASD), epilepsy and some inheritable metabolic disorders. Propionic acid (PPA) is a short chain fatty acid and an important intermediate of cellular metabolism. PPA is also a by-product of a subpopulation of human gut enterobacteria and is a common food preservative. We examined the behavioural, electrophysiological, neuropathological, and biochemical effects of treatment with PPA and related compounds in adult rats. Intraventricular infusions of PPA produced reversible repetitive dystonic behaviours, hyperactivity, turning behaviour, retropulsion, caudate spiking, and the progressive development of limbic kindled seizures, suggesting that this compound has central effects. Biochemical analyses of brain homogenates from PPA treated rats showed an increase in oxidative stress markers (e.g., lipid peroxidation and protein carbonylation) and glutathione S-transferase activity coupled with a decrease in glutathione and glutathione peroxidase activity. Neurohistological examinations of hippocampus and adjacent white matter (external capsule) of PPA treated rats revealed increased reactive astrogliosis (GFAP immunoreactivity) and activated microglia (CD68 immunoreactivity) suggestive of a neuroinflammatory process. This was coupled with a lack of cytotoxicity (cell counts, cleaved caspase 3' immunoreactivity), and an increase in phosphorylated CREB immunoreactivity. We propose that some types of autism may be partial forms of genetically inherited or acquired disorders involving altered PPA metabolism. Thus, intraventricular administration of PPA in rats may provide a means to model some aspects of human ASD in rats.

Animals↗