Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “LACTIC ACID”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

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

At least 487 records · Page 27Linked to original sources
PubMed2003

Determination of serum D-lactic and L-lactic acids in normal subjects and diabetic patients by column-switching HPLC with pre-column fluorescence derivatization.

d-Lactic and l-lactic acids were simultaneously determined by means of a column-switching high-performance liquid chromatography (HPLC) with fluorescence detection. As a fluorescence reagent, 4-nitro-7-piperazino-2,1,3-benzoxadiazole (NBD-PZ) was employed for the fluorescence derivatization of lactic acid. The proposed HPLC system adopted both octylsilica (Cadenza CD-C8) and amylose-based chiral columns (CHIRALPAK AD-RH), which proved to give a sufficient enantiomeric separation of the lactic acid derivatives with a separation factor ( alpha) of 1.32 and a resolution ( R(s)) of 1.98. Moreover, the features of the first elution of d-lactic acid peak in the proposed HPLC were convenient for the determination of trace amount of serum d-lactic acid, which is known to increase under diabetes. Intra-day and inter-day accuracies were in the range of 90.5-101.2 and 89.0-100.7%, and the intra-day and inter-day precisions were 0.3-1.2 and 0.4-4.8%, respectively. The proposed method was applied to determine d-lactic and l-lactic acids in human serum of normal subjects and diabetic patients, showing that both d-lactic and l-lactic acid concentrations were significantly increased in the serum of diabetic patients ( n=31) as compared with normal subjects ( n=21). This fact was found for the first time owing to the development of the proposed HPLC method which is able to determine d-lactic and l-lactic acid simultaneously. Finally, serum d-lactic acid concentrations determined by the proposed HPLC method were compared with those from a reported enzymatic assay, and the smaller p value between normal subjects and diabetic patients was shown by the proposed HPLC method.

Adult↗
PubMed2006

Treatments using hot water instead of lactic acid reduce levels of aerobic bacteria and Enterobacteriaceae and reduce the prevalence of Escherichia coil O157:H7 on preevisceration beef carcasses.

Lactic acid has become the most commonly used organic acid for treatment of postevisceration beef carcasses. Many processors have also implemented 2% lactic acid washes on preevisceration carcasses. We previously demonstrated that hot water washing and steam vacuuming are effective carcass interventions. Because of the effectiveness of hot water, we compared its use with that of lactic acid as a preevisceration wash in a commercial setting. A commercial hot water carcass wash cabinet applying 74 degrees C (165 degrees F) water for 5.5 s reduced both aerobic plate counts and Enterobacteriaceae counts by 2.7 log CFU/100 cm2 on preevisceration carcasses. A commercial lactic acid spray cabinet that applied 2% L-lactic acid at approximately 42 degrees C (105 to 110 degrees F) to preevisceration carcasses reduced aerobic plate counts by 1.6 log CFU/100 cm2 and Enterobacteriaceae counts by 1.0 log CFU/100 cm2. When the two cabinets were in use sequentially, i.e., hot water followed by lactic acid, aerobic plate counts were reduced by 2.2 log CFU/100 cm2 and Enterobacteriaceae counts were reduced by 2.5 log CFU/100 cm2. Hot water treatments reduced Escherichia coli O157:H7 prevalence by 81%, and lactic acid treatments reduced E. coli O157:H7 prevalence by 35%, but the two treatments in combination produced a 79% reduction in E. coli O157:H7, a result that was no better than that achieved with hot water alone. These results suggest that hot water would be more beneficial than lactic acid for decontamination of preevisceration beef carcasses.

Animals↗
PubMed2005

Genomic features of lactic acid bacteria effecting bioprocessing and health.

The lactic acid bacteria are a functionally related group of organisms known primarily for their bioprocessing roles in food and beverages. More recently, selected members of the lactic acid bacteria have been implicated in a number of probiotic roles that impact general health and well-being. Genomic analyses of multiple members of the lactic acid bacteria, at the genus, species, and strain level, have now elucidated many genetic features that direct their fermentative and probiotic roles. This information is providing an important platform for understanding core mechanisms that control and regulate bacterial growth, survival, signaling, and fermentative processes and, in some cases, potentially underlying probiotic activities within complex microbial and host ecosystems.

Food Microbiology↗
PubMed1994

Utilization of Lactic Acid by Fusarium oxysporum var. lini: Regulation of Transport and Metabolism.

Lactic acid was transported in Fusarium oxysporum var. lini ATCC 10960 by a saturable transport system that had a half-saturation constant of 56.6 +/- 7.5 muM and a maximum velocity of 0.61 +/- 0.10 mmol h g (dry weight) at 26 degrees C and pH 5.0. This transport system was inducible and was not expressed in the presence of a repressing substrate. Evidence is presented that the anionic form lactate was taken up by the cells. Propionic, acetic, pyruvic, and bromoacetic acids but not succinic acid competitively inhibited the transport of lactic acid. Bromoacetic acid, which was not metabolized, was taken up to a steady-state level when intracellular and extracellular concentrations were identical, indicating that the transport system was not accumulative. The enzymatic activity that was physiologically more relevant in the metabolism of lactic acid was lactate: ferricytochrome c oxidase. This enzyme did not exhibit stereospecifity and was induced by lactic acid.

Journal Article↗
PubMed1975

Stimulation of lactic acid production in chick embryo fibroblasts by serum and high pH in the absence of external glucose.

Lactic acid production by chick embryo fibroblasts occurs in the absence of exogenous glucose. Fifteen to 50-fold less lactic acid is formed in the absence of glucose than in its presence. Nevertheless, serum and pH stimulation enhances this residual lactic acid production to the same relative extent as when glucose is present. The amount of lactic acid formed cannot be accounted for by the catabolism of residual glucose in the medium since its concentration is less than one-tenth that of the lactic acid eventually produced. Moreover, the residual glucose concentration remains constant or increases during the course of the experiment. To a large extent lactic acid accumulation in the absence of external glucose is dependent on the presence of amino acids in the medium, but amino acid transport is not affected by the stimulatory agents used in this study. The results suggest that treatments which stimulate cell multiplication also activate those enzymatic pathways which convert amino acids to pyruvic and thence to lactic acid.

Amino Acids↗
PubMed1984

[Effects of muscular exertion in a hypoxic and hypoxic-hypercapnic respiratory environment on acid-base equilibrium and blood lactic acid in the albino rat raised in hypoxic hypoxia from birth].

Albino rats of the Wistar family were raised from the time of birth in the normobaric hypoxic environment. They were subjected at two subsequent equal trials of muscular work: the first in hypoxic normobaric conditions; the second in hypoxic hypercapnic conditions (CO2 = 2%). The modifications of the lactacidemia and acid-base balance at the end of the first trial are modest, lower than these observed in previous studies in normoxic rats. Added CO2 sensitively reduced the effects of the muscular work on the examined parameters.

Acid-Base Equilibrium↗
PubMed1978

Measurement of lactic acid in cerebrospinal fluid of patients with infections of the central nervous system.

The concentration of lactic acid in cerebrospinal fluid (CSF) was determined by gas-liquid chromatography in 205 samples of CSF from 97 patients with or without infections of the central nervous system. Patients without infection or those with nonbacterial (presumably viral) meningitis consistently had low concentrations of lactic acid in CSF (i.e., less than or equal to 35 mg/100 ml), whereas patients with bacterial or tuberculosis meningitis consistently had concentrations of lactic acid in CSF of greater than 35 mg/100 ml. There was no overlap in concentrations of lactic acid between these two groups. Further, lactic acid concentrations in CSF from patients partially treated for meningitis were generally greater than 35 mg/100 ml through the third day of therapy and, thereafter, progressively declined to less than 20 mg/100 ml by the seventh to 10th day of therapy. Relapse of bacterial infection was consistently documented by a recurrence of an increased concentration of lactic acid in CSF. Preliminary experience with determination of the concentration of lactic acid in CSF suggests that it may be useful in distinguishing bacterial (with or without positive cultures) and tuberculous meningitis from meningitis due to nonbacterial causes.

Adolescent↗
PubMed1997

Stimulation of pulmonary C fibres by lactic acid in rats: contributions of H+ and lactate ions.

1. The contributions of H+ and lactate ions to the stimulation of single pulmonary C fibres by lactic acid were examined in anaesthetized and artificially ventilated rats. 2. Lactic acid injected into the right atrium caused a transient decrease in arterial blood pH (pHa) and a short but intense burst of afferent activities in pulmonary C fibres, whereas sodium lactate had no effect. The fibre activity usually reached a peak within 1-1.5 s, with an onset latency of < 1 s, and returned to the baseline in 5 s. 3. The injection of hydrochloric acid at the same pH as that of lactic acid did not significantly decrease pHa, nor did it stimulate any C fibres studied. 4. Formic acid has a pKa value (the negative logarithm of the dissociation constant) almost identical to that of lactic acid; thus, its injection decreased pHa to the same degree as did the injection of lactic acid. However, the response of C fibres to lactic acid was 134% stronger than that to formic acid. 5. We conclude that H+ is primarily responsible for the activation of pulmonary C fibres by lactic acid, probably through a direct effect of H+ on these afferent endings. The lactate ion, by itself, does not activate C fibres, but it seems to potentiate the stimulatory effect of H+ on these afferents.

Action Potentials↗
PubMed2000

Anion antiport mechanism is involved in transport of lactic acid across intestinal epithelial brush-border membrane.

Intestinal epithelial membrane transport of L-lactic acid was characterized using rabbit jejunal brush-border membrane vesicles (BBMVs). The uptake of L-[(14)C]lactic acid by BBMVs showed an overshoot phenomenon in the presence of outward-directed bicarbonate and/or inward-directed proton gradients. Kinetic analysis of L-[(14)C]lactic acid uptake revealed the involvement of two saturable processes in the presence of both proton and bicarbonate gradients. An arginyl residue-modifying agent, phenylglyoxal, inhibited L-[(14)C]lactic acid transport by the proton cotransporter, but not by the anion antiporter. The initial uptakes of L-[(14)C]lactic acid which are driven by bicarbonate ion and proton gradients were inhibited commonly by monocarboxylic acids and selectively by anion exchange inhibitor 4, 4'-diisothiocyanostilbene-2,2'-disulfonic acid and protonophore carbonylcyanide p-trifluoromethoxyphenylhydrazone, respectively. These observations demonstrate that L-lactic acid is transported across the intestinal brush-border membrane by multiple mechanisms, including an anion antiporter and a previously known proton cotransporter.

Animals↗
PubMedDate not supplied

The importance of lactic acid levels in body fluids in the detection of bacterial infections.

Lactic acid can be formed as a "blind alley" in the metabolic degradation of glucose, especially under anaerobic conditions. The presence of bacterial infection in a closed body cavity induces elevated levels of lactic acid, as is evident in bacterial and fungal infections inthe meninges, joints, peritoneum, and pleura. Although measurement of lactate levels is not a test without faults, it is still a valuable tool in the early recognition of bacterial infections of various body cavities and can assist in the differentiation between infectious and noninfectious conditions. False-positive readings can be obtained with severe anoxia of the CNS, and with irritation of the peritoneal or pleural cavities due to metastases. False-negative values can be obtained in gonococcal arthritis. Table 1 presents accepted normal values for lactic acid in various body sites and the levels of lactic acid than can signify the presence of infection. Further work is still needed to provide better understanding of the mechanisms that cause changes in concentrations of lactic acid.

Ascitic Fluid↗
PubMed1993

Non-invasive sampling of lactic acid ions by iontophoresis using chloride ion in the body as an internal standard.

Non-invasive sampling of lactic acid, as a model endogenous compound, through hairless rat skin by iontophoresis was investigated using a two-chamber iontophoretic diffusion cell equipped with platinum electrodes and a pulse depolarization iontophoretic system. Chloride ion in the body was used as an internal standard. First, an in vitro experiment on the permeation of lactate and chloride ions through hairless rat skin was carried out to determine the flux ratio of these ions. The cathode side of the cell (dermis side) was filled with physiological saline containing lactic acid (0.5556, 1.111, 1.667 or 2.222 mmol cm-3) and the anode side (epidermis side) with phosphate buffer (pH 7.4). The amount of lactate and chloride ion permeated from the dermis side to the epidermis side through the skin at a constant current of 3.0 mA was determined using an automatic lactic acid analyser and high-performance ion chromatography, respectively. For construction of a calibration curve of lactic acid in the dermis side, the ionic mobility ratio of lactic acid/chloride ion (UCl/Ulac) was determined using a computer simulation program from the flux ratio of lactic acid and chloride ion and the applied concentration of lactic acid in the dermis side. Second, an in vitro non-invasive sampling experiment of lactic acid through rat skin was carried out at a constant current of 2.0 or 3.0 mA and 2.222 or 1.111 mmol cm-3 of lactic acid in the dermis side, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2003

Lactic acid production through cell-recycle repeated-batch bioreactor.

The effect of various nitrogen sources on cell growth and lactic acid production was investigated. The most effective nitrogen source was yeast extract; more yeast extract gave higher cell growth and lactic acid productivity. Yeast extract dosage and cell growth were proportional up to a yeast extract concentration of 30 g/L, and lactic acid productivity was linearly correlated up to a yeast extract dosage of 25 g/L. However, increasing the yeast extract content raises the total production cost of lactic acid. Therefore, we attempted to find the optimum yeast extract dosage for a repeated-batch operation with cell recycling. The results show that when using Enterococcus faecalis RKY1 only 26% of the yeast extract dosage for a conventional batch fermentation was sufficient to produce the same amount of lactic acid, whereas the lactic acid concentration in the product stream (92-94 g/L) and lactic acid productivity (6.03-6.20 g/[L x h]) were similar to those of a batch operation. Furthermore, long-term stability was established.

Bioreactors↗
PubMed1990

The effect of treatment with buffered lactic acid on microbial decontamination and on shelf life of poultry.

The use of buffered lactic acid systems compared with unbuffered lactic acid solutions enhances the decontaminating effect and increases shelf life of chicken legs. A reduction of about 2 pH units of the chicken skin is obtained by treatment with 10% lactic acid buffer. The buffer keeps the pH of the skin lower than that of untreated legs. Legs treated with 10% lactic acid buffer have a shelf life of 12 days at 6 degrees C, which means an increase of 6 days compared with the shelf life of untreated legs.

Animals↗
PubMed2003

Lack of inhibitory effects of lactic acid bacteria on 1,2-dimethylhydrazine-induced colon tumors in rats.

AIM: A myriad of healthful effects has been attributed to the probiotic lactic acid bacteria, perhaps the most controversial issue remains that of anticancer activity. This study was aimed at investigating the putative anti-cancer effects of lactic acid bacteria strains on the progression of colon tumor in 1,2-dimethylhydrazine (DMH)-treated animals. METHODS: The strain of lactic acid bacteria used in this study was lactic acid bacteria NZ9000 that conformed to the characteristics of plasmid free. Sixty male Wistar rats were given subcutaneous injections of DMH at a dose of 40 mg/kg body wt or saline once a week for 10 weeks. The rats were divided into 6 experimental groups. After the last DMH injection, animals in groups 1 and 4 were gavaged with 1 ml of lactic acid bacteria at a dose of 5 X 10(9) per day or vehicle until sacrifice at the end of week 22 or week 52. Animals in groups 1-3 were killed at the end of week 22 for histopathological examination. The whole period of experimental observation was 52 weeks. RESULTS: By the end of 22nd week, final average body weights of the rats treated with DMH alone and all animals receiving lactic acid bacteria were significantly decreased compared with the vehicle control (P<0.05). No differences in tumor incidence, multiplicity, dimensions and stage in the colonic mucosa were observed among the groups. At week 52, the survival rate of the rats administered lactic acid bacteria was lower than that of the rats treated with DMH that were fed on control fluids of non-lactococcus lactis. The mean survival time of lactic acid bacteria-treated animals was 39 weeks. CONCLUSION: These results indicate that lactic acid bacteria lacks inhibitory effects on the progression of colon tumor in DMH-treated animals, and does not support the hypothesis that alteration of colonic flora may exert an influence on the progression of colon tumor.

1,2-Dimethylhydrazine↗
PubMed1989

Effect of inoculation rate of selected strains of lactic acid bacteria on fermentation and in vitro digestibility of grass-legume forage.

Grass-legume forage was used to evaluate the effect of inoculation rate of selected strains of lactic acid bacteria on fermentation and in vitro digestibility during 57 d of ensiling. Chopped forage (DM = 28%) was ensiled in 4 to 6-kg quantities and treated as: 1) control, 10(3) epiphytic lactic acid bacteria; 2) 10(5) added lactic acid bacteria; and 3) 10(6) added lactic bacteria/g of wet forage. Samples were obtained for analyses on d 0, 1, 2, 3, 6, 10, 14, 29, and 57 of fermentation. Treated silages were observed to have: 1) greater quantities of lactic acid bacteria, 2) a greater proportion of homofermentative lactic acid bacteria, and 3) lactic acid bacteria with greater biological activity. Addition of each amount of lactic acid bacteria: 1) increased the rate of utilization of water-soluble carbohydrate and decline in pH, 2) limited the formation of NH3 N, and 3) increased the in vitro digestibility of DM and ADF. No differences were observed in the lactic acid content of the silages after 57 d of fermentation.

Ammonia↗