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PubMed2003

EMG activities of facial and chewing muscles of human adults in response to taste stimuli.

To evaluate facial expression patterns induced by different taste stimuli, electromyograms (EMG) of the facial and chewing muscles of 12 healthy university students, aged 20 to 23 years, were analyzed. Sucrose (sweet), NaCl (salty), citric acid (sour), quinine-HCl (bitter), monosodium glutamate (MSG; umami), homogentisic acid (harsh), tannic acid (astringent), and capsaicine (pungent) were the taste stimuli used. Rating scale tests were made to assess the hedonics (pleasantness) of the taste stimuli. EMG responses of the corrugator supercilii, venter frontalis, orbicularis oculi, depressor anguli, and digastricus muscles to capsaicine, tannic, acid, and citric acid showed larger amplitudes than to NaCl, MSG, homogentisic acid, and sucrose. Increases in EMG responses for most facial and chewing muscles for the taste solutions had significant negative correlations to the solutions' hedonic scale values. Most facial and chewing muscles of adult humans therefore showed greater responses to disliked than to preferred or less preferred tastes.

Adult↗
PubMed1989

Studies on adhesion to tooth substrate. 6. Adhesion of composite resin to dentin mediated by the dentin primer containing MTYA.

The influences of the kinds and concentrations of the aldehydes in the primer on dentin adhesion were investigated. Moreover, the durability of the adhesion to the dentin treated with primer was examined by thermal cycling tests. Among the aldehyde tested here, glutaraldehyde was effective in improving the adhesion to dentin etched with citric acid. When HEMA was substituted with ethanol, the bond strengths decreased. The relationship between the bond strength and the concentration of glutaraldehyde in the primer was studied. In the cases of phosphoric acid or citric acid etching, the bond strengths were affected by the concentration of glutaraldehyde in the primer. The bond strengths decreased after 2000 thermocycles in phosphoric acid etching.

Adhesiveness↗
PubMed2000

Acidified sodium chlorite antimicrobial treatment of broiler carcasses.

An acidified sodium chlorite (ASC) solution was investigated for its antimicrobial effects on broiler carcasses processed under conditions similar to those used in U.S. commercial poultry facilities. Of particular interest was the ability of the ASC solution to reduce natural bioburden in a prechill procedure. A number of parameters such as pretreatment washing of carcasses with water (no wash versus water wash), ASC concentration (500, 850, and 1,200 ppm), method of application (spray versus dip), and method of acid activation (phosphoric acid versus citric acid) were explored to evaluate disinfection conditions. ASC dip solutions (18.9 liters) were freshly prepared for groups of five prechill eviscerated carcasses per treatment (n = 10 carcasses). ASC treatment was shown to be an effective method for significantly reducing naturally occurring microbial contamination on carcasses. Reductions following immersion dipping were demonstrated at all disinfectant concentrations for total aerobes (82.9 to 90.7%), Escherichia coli (99.4 to 99.6%), and total coliforms (86.1 to 98.5%). Additionally, testing showed that ASC solutions maintained stable pH and minimal chlorite ion concentration deviations throughout each treatment. The results of the parameter evaluations indicated that maximal antimicrobial activity was achieved in carcasses that were prewashed and then exposed to a 5-s dip in a solution containing phosphoric acid- or citric acid-activated ASC. At 1,200 ppm ASC, a mild but transitory whitening of the skin was noted on dipped carcasses. The results support the methods currently approved by the U.S. Department of Agriculture for the use of ASC solutions as a prechill antimicrobial intervention in U.S. poultry processing plants.

Animals↗
PubMed2001

[Protective effects of organic acids on human vascular endothelial cells].

OBJECTIVES: In order to examine if organic acids (OA), a kind of natural food components, will prevent from atherosclerosis formation, the effects of four OA, namely chlorogenic acid (CHA), ascorbic acid (AA), citric acid (CA), and malic acid (MA) on human vascular endothelial cells were studied. METHODS: Primary human umbilical vein endothelial cells (EC) were cultured, and the changes of cell morphology, cell growth, lactate dehydrogenase (LDH) released from cells were measured when EC was incubated with oxidized low density lipoprotein (oxLDL) in the presence or not of four OA added at three different conditions, i.e. before 4 hours oxLDL added, at the same time as oxLDL added, and after 3 hours oxLDL added, as well as at the indicated doses (10, 20 or 40 mg/L). RESULTS: The EC survival rate of the oxLDL control group was lower (P < 0.01) and LDH release rate was higher (P < 0.01) than those of normal control group. CHA, AA, CA and MA protected EC from damage caused by oxLDL when they were added before and/or at the same time of oxLDL, but the same beneficial effects of these four OA added after oxLDL were not observed. The EC survival rates of CHA + oxLDL and AA + oxLDL groups in three doses were higher (P < 0.05) and the LDH release rates were lower (P < 0.05) in a dose-effect manner when compared with those of oxLDL control group, respectively. Similar results were found in the CA + oxLDL and MA + oxLDL of the high dose groups. CONCLUSION: Four tested OA could effectively prevent EC from damage induced by oxLDL. CHA and AA had the strongest effects, the next was CA, followed by MA.

Arteriosclerosis↗
PubMed1989

[Studies on adhesion of MMA (TBB-O) resin to dentin. The efficacy of the primer treatment].

In this study the efficacy of the primer on adhesion of MMA (TBB-O) resin to dentin was investigated. The primer consists of two parts. One is 6% MTYA and 70% HEMA aqueous solution, and the other is 2% glutaraldehyde aqueous solution. As an etching agents, 10% citric acid-3% FeCl3 (10-3), 40% phosphoric acid, 10% citric acid, and 0.5 M EDTA were used. After etching, the two parts of the primer were mixed well and applied on the etched surface. Then MMA (TBB-O) resin or p-MBA/MMA (TBB-O) resin was applied on the treated surface. The tensile bond strengths after storage in 37 degrees C water were measured. It revealed that the primer treatment increased the bond strength despite the kind of etching agents. Though the thickness of the resin reinforced dentin was the same as that of demineralized dentin, it was not proportional to the bond strength. Then the durability of the adhesion to dentin treated with primer was examined by the thermal cycling tests. After 2000 thermocycles between 5 degrees C and 55 degrees C, the decrease in the bond strength was very small.

Acid Etching, Dental↗
PubMed1982

[Studies on dental self-curing resins (19) - adhesion of 4-META/MMA-TBB resin to pretreated dentine (author's transl)].

A new 4-META/MMA-TBB adhesive resin has been studied and the effectiveness on adhesion to tooth substrates and dental alloys was reported previously. Here we are showing affection of cleaner or etchants on the adhesion between dentines and the 4-META/MMA-TBB resin. The adhesive strength becomes superior, 18 MPa, when dentines have been cleaned with a 10% citric acid-3% ferric chloride solution. On the other hand an etchant, phosphoric acid or citric acid alone, is not so effective as the mixed solution and the strength decreases to 6 MPa. Scanning electron microscopic study on pretreated dentine with several solutions is also carried out and it is found that debris on dentine should be removed but that in tubules is not necessary to be cleaned up to get good adhesion.

Acrylic Resins↗
PubMed1986

Evaluation of a rapid technique for antibody elution.

This study evaluated a new rapid acid elution technique using citric acid. This technique was compared to the commonly used digitonin acid procedure. Twenty patient or donor antibodies with specificities in the Rhesus, Kell, Kidd, or Duffy systems were used to coat red cells. Eluates produced from these cells by the citric acid procedure were equivalent or greater in volume and potency to those produced by a digitonin acid method. The citric acid procedure required five to nine minutes to complete, while the digitonin acid procedure required 28 to 44 minutes. The citric acid technique is a rapid means of producing a potent eluate.

Journal Article↗
PubMed2000

On-line preconcentration of niobium(V) and tantalum(V) as 4-(2-pyridylazo) resorcinol-citrate ternary complexes in geological samples by ion interaction high-performance liquid chromatography.

4-(2-Pyridylazo) resorcinol (PAR) and citrate were used as pre-column complexing agents for the determination of Nb(V) and Ta(V) as ternary complexes in geological samples. Aliquots of 2 ml of the standard and sample solutions containing the Nb(V) and Ta(V) complexes were loaded onto a concentrator column (C18, 0.4 cm x 4.6 mm) with a carrier mobile phase comprising 20% (v/v) methanol and containing 5 mM acetic acid, 5 mM citric acid and 10 mM tetrabutylammonium bromide (TBABr), pH 6.5 at 2 ml/min for 2 min, with the effluent being directed to waste. An automatic switching valve was then switched to flush both complexes from the concentrator column onto a C18 analytical column using a mobile phase comprising 32% (v/v) methanol and containing 5 mM acetic acid, 5 mM citric acid and 3 mM TBABr, pH 6.5 for 2.5 min. The switching valve was then switched back to the original position, and cleaned with methanol for 7 min to eliminate unwanted species still adsorbed to the concentrator column. This procedure prevented later eluting compounds from reaching the analytical column, which reduced the overall run time. The detection limits of Nb(V) and Ta(V) (determined at a signal-to-noise ratio of 3, detection wavelength of 540 nm and a 2-ml sample volume) were 0.012 and 0.039 ppb for Nb(V) and Ta(V), respectively. Recoveries of Nb(V) and Ta(V) were 99.4 and 96.2%, respectively. The HPLC results obtained from the reference granite and basalt samples agreed well with inductively coupled plasma MS and certified values, but the HPLC method yielded slightly low values of the Nb/Ta ratio.

Chromatography, High Pressure Liquid↗
PubMed2005

Eradication of Helicobacter pylori can be accurately confirmed 14 days after termination of triple therapy using a high-dose citric acid-based 13C urea breath test.

BACKGROUND: Confirmation of Helicobacter pylori eradication by urea breath test (UBT) is currently performed 4-6 weeks after completion of therapy because of unacceptable false-negative results in UBTs performed earlier. Use of a high-dose citric acid test meal appears to enable accurate detection of H. pylori even during short term therapy with proton pump inhibitors. AIM: To evaluate if use of a high dose citric acid (4.0 g) test meal can decrease the interval required for confirmation of eradication after triple therapy. METHODS: 233 patients positive for H. pylori were randomized to undergo UBT at 7 days or 14 days after triple therapy, and again at 6 weeks. The latter test was considered the gold standard test. RESULTS: The UBT performed 6 weeks after the end of treatment found that 79.9% were cured. The same test 7 days after therapy found false-negative detection of H. pylori in 7.3% patients compared to 3.2% patients examined after 14 days. The sensitivity, specificity, positive and negative predictive values and accuracy for evaluation on day 14 were 80, 100, 100, 96.3 and 96.7%, respectively. CONCLUSIONS: High-dose citric acid-based UBT is a valid test for the assessment of H. pylori status 14 days after triple therapy. This may obviate the delay in instituting second-line eradication therapy, or further evaluation of the symptomatic patient unresponsive to therapy despite eradication.

Adolescent↗
PubMed1991

Ruthenium red decreases capsaicin and citric acid-induced cough in guinea pigs.

The influence of aerosols of Ruthenium red (RR) on capsaicin- and citric acid-induced cough was investigated in guinea pigs. Aerosols of RR (0.3, 1, 3%) reduced capsaicin-induced cough in dose-dependent manner. Inhalation of RR also reduced cough produced by low, (200 mM) but not high (550 mM), concentrations of citric acid. These data suggest that RR is not a specific capsaicin antagonist and that citric acid and capsaicin share a common mechanism for activation of airway C-fibers that is RR sensitive. Furthermore, high concentrations of citric acid can elicit cough through a RR-insensitive mechanism.

Aerosols↗
PubMed2002

The maintenance diets of C57BL/6J and 129X1/SvJ mice influence their taste solution preferences: implications for large-scale phenotyping projects.

We examined the extent to which maintenance diet influences the taste preferences of mice. C57BL/6J (B6) and 129X1/SvJ (129) mice were fed one of three standard cereal-based diets (Teklad 8604, Zeigler NIH-07, Purina 5001), a cereal-based diet formulated for breeding (Purina 5015), or two purified diets (AIN-76A or AIN-93G). The mice were given 48-h two-bottle choice tests between water and the following seven taste solutions: 2 mmol/L saccharin, 5 mmol/L citric acid, 50 mmol/L citric acid, 30 micro mol/L quinine hydrochloride (QHCl), 300 micro mol/L QHCl, 75 mmol/L NaCl, and 10% ethanol. There were very few differences in taste solution preference scores among mice of the same strain fed the three different versions of standard cereal-based diet. There were also very few differences in taste solution preference scores between mice of the same strain fed the two purified diets. However, the mice fed standard cereal-based diets generally drank more water and total fluid than did mice fed purified diets. There were larger differences between the B6 and 129 strains in saccharin and ethanol preference scores with mice fed standard cereal-based diets than purified diets. Conversely, there were larger differences between the B6 and 129 strains in citric acid and NaCl preference scores with mice fed purified diets than standard cereal-based diets. These results show that maintenance diet composition can have strain-dependent effects on taste solution preference. They illustrate that attention must be paid to the effects of diet on phenotype in screens of mutagenized mice and other genetic studies.

Alcohol Drinking↗
PubMed2000

Inhibiting effect of ammonia on citric acid-induced cough in pigs: a possible involvement of substance P.

The effect of ammonia on the cough response to citric acid and on substance P release from C-fibers involved in this reflex was assessed. For a period from one to four days, piglets were exposed, in an inhalation chamber, to ammonia at a concentration of 15 or 30 ppm. During exposure, cough induction tests were done every two days. Recovery of the cough reflex after ammonia exposure was also determined. In a separate group of piglets exposed for 2 days to 30 ppm ammonia, substance P content was determined in bronchial and tracheal lavage fluids and in the tracheal and bronchial mucosa. Ammonia (30 ppm) was found to inhibit coughing significantly (the cough frequency was reduced by 64%) after a two-day exposure. In animals exposed for 4 days to this ammonia concentration, the recovery ranged from 3 to 7 days (mean: 5 days). The same ammonia concentration also caused the substance P content to increase significantly in bronchoalveolar lavage fluid (to 432% of its initial value) and tracheal lavage fluid (to 149%) and to decrease significantly in the tracheal mucosa (-58%), however the content in bronchial mucosa was not significantly affected (-43%). Exposure to 15 ppm ammonia had no effect on the frequency of citric acid-induced coughing. In conclusion, ammonia inhibits citric acid-induced coughing in pigs at concentrations that can be detected in piggeries. This inhibitory effect may be related to substance-P depletion in C-fiber endings.

Ammonia↗
PubMed2006

Effects of thorax irradiation on citric acid-induced cough in guinea pigs.

Thoracic irradiation may cause an acute lymphocytic alveolitis or hypersensitivity pneumonitis. It is well known that cough reflex is sensitized by a number of inflammatory mediators. The purpose of the present study was to investigate the effect of the thoracic irradiation on the cough response in awake guinea pigs. Guinea pigs (Trik strain) were exposed to sham irradiation (n=16), a single irradiation dose of 10 Gy (n=12), and a fractionated irradiation dose (in five fractions) of 15 Gy (n=12) delivered to the thorax. Cough was induced by citric acid aerosol inhalation in gradually increasing concentrations (0.05-1.6 M) during the first week after thoracic irradiation. The cough response was expressed as a total number of coughs induced during all citric acid challenges. Irradiated animals with single dose of 10 Gy exhibited a time- dependent significant increase of citric acid-induced cough in the 6th day after irradiation compared with control animals (P=0.005), whereas cough was not altered significantly in irradiated animals with fractionated dose of 15 Gy. This study demonstrates that the increased cough response may be a determinant of the functional changes of airway nerve-endings mediating cough in the early phase after thoracic irradiation.

Animals↗
PubMed1988

Urinary biochemical profile of patients with ureteric calculi in Jodhpur region (north western India).

Urine chemistry of 42 normal subjects (NS) and 59 ureteric stone formers (SF) from Jodhpur region of Rajasthan, India is presented. Twenty four hour urinary levels of calcium, oxalic acid and uromucoids were significantly higher and levels of magnesium, citric acid and inorganic phosphorus were significantly lower in SF as compared to NS. No significant difference was observed in the uric acid, sodium and potassium levels in the two groups. Significant correlation was observed between calcium and magnesium; calcium and oxalic acid; calcium and citric acid; magnesium and oxalic acid; and oxalic acid and citric acid in NS on the basis of mmol/l but not on the basis of mmol/24 h. Calcium and oxalic acid correlation was uninfluenced by magnesium and citric acid levels. The log of risk factor index (RI) was higher (p less than 0.001) in SF (-1.652) as compared to NS (-2.103). The log of ion activity product (IAP) was also higher (p less than 0.001) in SF (-3.192 X 10(-3)) than in NS (-2.914 X 10(-1)). Based on RI and IAP, a scale has been devised for the prediction of the risk of stone formation and recurrence.

Adult↗
PubMed1997

Citric acid-induced cough thresholds in normal subjects, patients with bronchial asthma, and smokers.

Several challenge procedures have been developed to characterize the cough reflex in patients with airway diseases. This study was performed to compare the interindividual range of cough sensitivity in asthmatic and normal subjects as well as smokers using an identical method. Sixteen normal subjects, 20 patients with mild bronchial asthma, 6 patients with moderate to severe bronchial asthma, 9 current smokers, and 7 occasional smokers were included. In all subjects, methacholine challenges and standardized citric acid challenges were performed. Sensitivity of the cough reflex was expressed as cough threshold, i.e., as concentration at which coughing occurred. Reproducibility was assessed in 23 subjects. Within a concentration range of 0.625-320.0 mg/ml, inhaled citric acid caused cough in all subjects. Geometric mean (range) cough threshold was 13 (2.5-160) in normal subjects, 14 (5-40) in patients with mild, and 32 (20-40) mg/ml in patients with moderate to severe asthma, 40 (20-80) in current smokers, and 119 (80-160) in occasional smokers. Cough thresholds were reproducible within one doubling concentration. In normal subjects and patients with mild bronchial asthma, thresholds were not significantly different from each other but lower than those of the other groups (p<0.05 each). Cough thresholds in smokers and patients with moderate to severe asthma did also not differ significantly and were lower than in occasional smokers (p<0.05). There was no significant correlation between cough threshold, baseline FEV subset1 , and methacholine responsiveness. Our data indicate that (1) subjects with mild asthma showed on average similar cough thresholds as normal subjects, (2) there was a large variation in cough thresholds within groups, (3) the reproducibility of cough thresholds was within one doubling concentration, (4) cough thresholds did not correlate with methacholine responsiveness or baseline airway tone. In view of the prevalence of cough as a symptom of bronchial asthma, it appears that the determination of citric acid-induced cough thresholds does not yield additional diagnostic information in these subjects.

Administration, Inhalation↗
PubMed2000

Influence of phenolic compounds on the physiology of Oenococcus oeni from wine.

This study shows that the growth of Oenococcus oeni CECT 4100 in a synthetic medium is affected by phenolic compounds in different ways, depending on their type and concentration. Generally they have no effects at low concentrations, but hydroxycinnamic acids are inhibitory at high concentrations. Malolactic fermentation was stimulated in the presence of catechin and quercetin, but increasingly delayed with increasing amounts of p-coumaric acid. Gallic acid appeared to delay or inhibit the formation of acetic acid from citric acid. This could lead to a better control of malolactic fermentation and suppress the increase in volatile acidity, which is undesirable in the wine-making process.

Acetic Acid↗
PubMed2005

Separation of membranes from acid-solubilized fish muscle proteins with the aid of calcium ions and organic acids.

Calcium chloride, and to a lesser extent MgCl2, aided in the separation of membranes by centrifugation from cod (Gadus morhua) muscle homogenates solubilized at pH 3 in the presence of citric acid or malic acid but not lactic acid. Adding citric acid and Ca2+ before solubilizing the cod muscle homogenates was needed for the effect. At 1 mM citric acid, 70-80% of the phospholipid and 25-30% of the protein were removed at 10 mM Ca2+. At 8 mM Ca2+, citric acid showed an optimal effect on phospholipid removal at 5 mM with 90% of the phospholipid and 35% of the protein removed. The treatment with citric acid and Ca2+ was also effective in separating the membrane from solubilized herring (Clupea harengus) muscle homogenate. Ca2+ and citric acid might exert their influence by disconnecting linkages between membranes and cytoskeletal proteins.

Animals↗