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 1,603 records · Page 89Linked to original sources
PubMed1990

Changes in running speed, blood lactic acid concentration and hormone balance during sprint training performed at an altitude of 1860 metres.

The development of results of five national level sprinters (Group A) was followed up during a training period of two weeks at an altitude of 1860 m aiming at increase of strength and speed and after it. Changes in anaerobic capacity were monitored by making blood lactic acid determinations, and occurrence of any overstrain by serum testosterone, cortisol, growth hormone and SHBG (sex hormone binding globulin) determinations. A control group (Group B) trained simultaneously according to a similar programme at sea level. Maximal 150 m running speeds increased in Group A significantly during the two weeks at the altitude of 1860 m (p less than 0.001). No such increase was observable in Group B. Maximal 300 m running speeds and maximal lactic acid concentrations after running did not increase significantly in either group. Serum hormone levels did not change significantly either, in either group. Training at an altitude of 1860 m to increase strength and speed significantly improved results at the shorter distance of 150 m but had not significant effects on anaerobic capacity or on serum testosterone, cortisol, growth hormone or SHBG levels.

Adult↗
PubMed1988

Increased (L+)-lactic acid production in lysozyme-inactivated suspensions of human dental plaque.

The effect of lysozyme-inactivation on L(+)-lactic acid (LA) production in dental plaque suspensions was evaluated. From 10 children 24-h plaque was collected and lysozyme activity inhibited by addition of goat antiserum to human lysozyme. Acid production was stimulated by addition of glucose. The results showed significantly increased LA levels (50-150%) in lysozyme-inactivated plaque suspensions from 8 of the subjects compared to untreated controls. The increase in acid production activity was not related to plaque lysozyme levels. The findings indicate that the presence of lysozyme may be limiting on acid production in the early dental plaque.

Adolescent↗
PubMed1999

The expression signals of the Lactobacillus brevis slpA gene direct efficient heterologous protein production in lactic acid bacteria.

A cassette based on the expression signals of the Lactobacillus brevis surface (S)-layer protein gene (slpA) was constructed. The low-copy-number vector pKTH2095, derived from pGK12, was used as the cloning vector. The efficiency of slpA promoters in intracellular protein production was studied using three reporter genes, beta-glucuronidase (gusA), luciferase (luc) and aminopeptidase N (pepN) in three different lactic acid bacteria hosts: Lactococcus lactis, Lactobacillus plantarum and Lactobacillus gasseri. The S-layer promoters were recognized in each strain and especially L. lactis and Lb. plantarum exhibited high levels of transcripts. The production kinetics of reporter proteins was studied as a function of growth. The GusA, Luc and PepN activities varied considerably among the lactic acid bacterial strains studied. The highest levels of beta-glucuronidase and luciferase activity were obtained in L. lactis. The level of GusA obtained in L. lactis corresponded to over 15% of the total cellular proteins. The highest level of aminopeptidase N activity was achieved in Lb. plantarum where PepN corresponded up to 28% of the total cellular proteins at the late exponential phase of growth. This level of PepN activity is 30-fold higher than that in Lb. helveticus, which is the species from which the pepN gene originates.

Aminopeptidases↗
PubMed2000

Bone and shell contribution to lactic acid buffering of submerged turtles Chrysemys picta bellii at 3 degrees C.

To evaluate shell and bone buffering of lactic acid during acidosis at 3 degrees C, turtles were submerged in anoxic or aerated water and tested at intervals for blood acid-base status and plasma ions and for bone and shell percent water, percent ash, and concentrations of lactate, Ca(2+), Mg(2+), P(i), Na(+), and K(+). After 125 days, plasma lactate concentration rose from 1.6 +/- 0.2 mM (mean +/- SE) to 155.2 +/- 10.8 mM in the anoxic group but only to 25.2 +/- 6.4 mM in the aerated group. The acid-base state of the normoxic animals was stable after 25 days of submergence. Plasma calcium concentration (¿Ca(2+)) rose during anoxia from 3.2 +/- 0.2 to 46.0 +/- 0.6 mM and ¿Mg(2+) from 2.7 +/- 0.2 to 12.2 +/- 0.6 mM. Both shell and bone accumulated lactate to concentrations of 135.6 +/- 35.2 and 163.6 +/- 5.1 mmol/kg wet wt, respectively, after 125 days anoxia. Shell and bone ¿Na(+) both fell during anoxia but the fate of this Na(+) is uncertain because plasma ¿Na(+) also fell. No other shell ions changed significantly in concentration, although the concentrations of both bone calcium and bone potassium changed significantly. Control shell water (27.8 +/- 0.6%) was less than bone water (33.6 +/- 1.1%), but neither changed during submergence. Shell ash (44.7 +/- 0.8%) remained unchanged, but bone ash (41.0 +/- 1.0%) fell significantly. We conclude that bone, as well as shell, accumulate lactate when plasma lactate is elevated, and that both export sodium carbonate, as well as calcium and magnesium carbonates, to supplement ECF buffering.

Acid-Base Equilibrium↗
PubMed2006

Use of unsupervised and supervised artificial neural networks for the identification of lactic acid bacteria on the basis of SDS-PAGE patterns of whole cell proteins.

Conventional multivariate statistical techniques (hierarchical cluster analysis, linear discriminant analysis) and unsupervised (Kohonen Self Organizing Map) and supervised (Bayesian network) artificial neural networks were compared for as tools for the classification and identification of 352 SDS-PAGE patterns of whole cell proteins of lactic acid bacteria belonging to 22 species of the genera Lactobacillus, Leuconostoc, Enterococcus, Lactococcus and Streptococcus including 47 reference strains. Electrophoretic data were pre-treated using the logistic weighting function described by Piraino et al. [Piraino, P., Ricciardi, A., Lanorte, M. T., Malkhazova, I., Parente, E., 2002. A new procedure for data reduction in electrophoretic fingerprints of whole-cell proteins. Biotechnol. Lett. 24, 1477-1482]. Hierarchical cluster analysis provided a satisfactory classification of the patterns but was unable to discriminate some species (Leuconostoc, Lb. sakei/Lb. curvatus, Lb. acidophilus/Lb. helveticus, Lb. plantarum/Lb. paraplantarum, Lc. lactis/Lc. raffinolactis). A 7x7 Kohonen self-organizing map (KSOM), trained with the patterns of the reference strains, provided a satisfactory classification of the patterns and was able to discriminate more species than hierarchical cluster analysis. The map was used in predictive mode to identify unknown strains and provided results which in 85.5% of cases matched the classification obtained by hierarchical cluster analysis. Two supervised tools, linear discriminant analysis and a 23:5:2 Bayesian network were proven to be highly effective in the discrimination of SDS-PAGE patterns of Lc. lactis from those of other species. We conclude that data reduction by logistic weighting coupled to traditional multivariate statistical analysis or artificial neural networks provide an effective tool for the classification and identification of lactic acid bacteria on the basis of SDS-PAGE patterns of whole cell proteins.

Bacterial Proteins↗
PubMed2002

[Preparation of interferon-alpha-loaded poly-L-lactic acid lamellar particles].

Lamellar particles(lamellae) were prepared by non-solvent precipitation from crystalic poly-L-lactic acid (PLLA). The PLLA lamellae exhibite a diamond or stepped irregular shape with a size range between 3-5 microns. Prepared without any surfactants and dispersing agents, the lamellar particles have clean surface, which is advantageous for the adsorption of proteins. The PLLA lamellar particles adsorbed protein cytokine interferon-alpha (IFN-alpha) with an adsorption efficiency of > or = 95%. The release of loaded IFN could continue for more than 10 days. The cell incubation experiments showed that the PLLA lamellar particles were easy to be phagocytosed by macrophages. The immunological experiments showed that the biological activity of IFN-alpha loaded on the PLLA lamellar particle was effectively retained.

Adsorption↗
PubMed1996

Inhibition of the accumulation of uremic toxins in the blood and their precursors in the feces after oral administration of Lebenin, a lactic acid bacteria preparation, to uremic patients undergoing hemodialysis.

The plasma levels of phenol, p-cresol, and indican are markedly increased in uremic patients, and cannot be efficiently reduced by hemodialysis. Such uremic toxins, which are produced in the intestine as bacterial putrefactive metabolites, accumulate to a great degree in the feces of hemodialysis patients. Oral administration of Lebenin, a preparation consisting of antibiotic-resistant lactic acid bacteria, reduced the levels of fecal putrefactive metabolites to levels comparable with those of healthy subjects. Moreover, the plasma level of indican also significantly decreased in these Lebenin-treated patients. An analysis of the fecal microflora revealed that a disturbed composition of the microflora characterized by an overgrowth of aerobic bacteria is restored to normal by oral administration of Lebenin in hemodialysis patients. These results thus demonstrate that oral administration of lactic acid bacteria in uremic patients is effective in reducing the levels of uremic toxins, especially that of indican, in the blood by inhibiting bacterial production by means of correcting the intestinal microflora.

Administration, Oral↗
PubMed2005

Phenotypic identification and technological properties of lactic acid bacteria isolated from traditionally processed fish products of the Eastern Himalayas.

Sukako maacha, gnuchi, sidra and sukuti are traditional smoked and sun-dried fish products of the Eastern Himalayan regions of Nepal and India. A total of 40 samples of sukako maacha (14), gnuchi (6), sidra (10) and sukuti (10) were collected and were analysed for microbial load. Population of lactic acid bacteria (LAB) as well as aerobic mesophilic counts ranged from 4.7-8.3 to 5.1-8.5 log cfu g(-1), respectively. A total of 189 strains of LAB were isolated from sukako maacha, gnuchi, sidra and sukuti samples, out of which 171 strains were cocci and 15 strains, were heterofermentative lactobacilli. LAB were identified on the basis of phenotypic characters including API system as Lactococcus lactis subsp. cremoris, Lactococcus lactis subsp. lactis, Lactococcus plantarum, Leuconostoc mesenteroides, Enterococcus faecium, Enterococcus faecalis, Pediococcus pentosaceus and Weissella confusa. LAB strains produced a wide spectrum of enzymes. Some strains of LAB showed antagonistic properties against pathogenic strains. None of the strains produced biogenic amines in the method applied. This paper is the first report on the microbial composition, mostly lactic acid bacteria, of traditionally processed fish products of Eastern Himalayas.

Animals↗
PubMedDate not supplied

Weak light emission patterns from lactic acid bacteria.

Distinct low level chemiluminescence patterns during aerobic growth of a selection of bacterial strains of the lactic acid group were recorded in on-line measurements. These patterns may be specific for the strain and the medium employed for cultivation. The patterns are oxygen-dependent and consist in the case of Enterococcus faecalis of three basic patterns, which reflect different mechanisms leading to both the generation and depletion of initiators of the chemiluminescence, particularly hydrogen peroxide and superoxide radical. The influence of catalase and superoxide dismutase on the patterns was examined. We could demonstrate the sensitivity of chemiluminescence measurements for the detection of both exogenous oxidative stress, which is imposed to the cells by reactive species formed in the medium, as well as endogenous oxidative stress, which is due to products of the cellular oxygen metabolism, the latter being often the reason for growth restriction.

Animals↗
PubMed2005

Lactic acid decreases Fe(II) and Fe(III) retention but increases Fe(III) transepithelial transfer by Caco-2 cells.

Lactic acid (LA) has been proposed to be an enhancer for dietary iron absorption, but contradictory results have also been reported. In the present study, fully differentiated Caco-2 cell monolayers were used to evaluate the effects of LA (1-50 mmol/L) on the cellular retention and transepithelial transport of soluble non-heme iron (as ferric nitrilotriacetate). Our data revealed a linear decline in Fe(III) retention with respect to the concentration of LA added. In the presence of 50 mmol/L LA, retention of Fe(III) and Fe(II) decreased 57% and 58%, respectively. In contrast, transfer of Fe(III) across the cell monolayer was doubled, while Fe(II) transfer across the cell monolayer decreased 35%. We conclude that LA reduces cellular retention and transepithelial transport of Fe(II) by Caco-2 cells in a dose-dependent manner. However, while LA also reduces retention of Fe(III) by Caco-2 cells, the transfer of Fe(III) across cell monolayers is enhanced, possibly due to effects on paracellular transport.

Biological Transport↗
PubMed2007

Effect of sterilization on the physicochemical properties of molded poly(L-lactic acid).

In this study, the process of manufacturing and sterilizing an orthopedic implant constructed from poly(L-lactic acid) (PLLA) was closely simulated. The hydrogen peroxide gas plasma (HPGP) sterilization process was comparatively investigated against ethylene oxide (EtO). Characterization of the physical, thermal, mechanical, morphological, and chemical properties was monitored. The results indicate that the HPGP sterilization process did not have a significant influence on M(n) or M(w) initially or through 12 weeks of in vitro conditioning when compared with EtO. Only indications of physical aging were evident in the analysis of the thermal and mechanical properties by differential scanning calorimeter and tensile testing for each sterilization processes. Using wide angle X-ray diffraction to determine morphology characteristics, it was determined that no changes were observed between the as molded, HPGP, and EtO specimens initially or through the 12 week in vitro conditioning period. Contact angle measurements revealed a significant reduction in the surface energy following treatment by the HPGP process, suggesting the formation of polar groups. However, surface chemistry analysis by ATR-FTIR indicated no significant chemical modification from either sterilization method. PLLA showed intermediate levels of residual hydrogen peroxide absorption following processing by HPGP.

Biocompatible Materials↗
PubMed1991

Treatment of malignant pleural effusions with doxorubicin hydrochloride-containing poly(L-lactic acid) microspheres.

For the treatment of malignant pleural effusions, we prepared doxorubicin hydrochloride (Adriamycin)-containing poly(L-lactic acid) microspheres (ADR-MS). In vitro, 50 percent and 100 percent release times of ADR from ADR-MS were 6.3 and 20 days, respectively. After intrapleural administration of ADR-MS for seven patients at an ADR dose of 40 mg, ADR was detected in the effusions for more than two weeks; however, ADR concentrations in serum were very small, consistent with minimal transpleural absorption of ADR. These results indicated the slow release of ADR into the pleural cavity. Furthermore, the amount of drained ADR was less than a few percent of the administered dose. In some cases, malignant cells in the effusion disappeared after the treatment. No complications related to the procedure occurred, and the patients developed no systemic symptoms. One patient died after four months, and the other six patients are alive after 21 to 31 months without reaccumulation of the effusion. The local administration of ADR-MS produces a localized high and systemic low concentration of ADR, which could potentially improve the patient's quality of life.

Aged↗
PubMed1993

Controlled release of insulin from plasma-irradiated sandwitch device using poly-DL-lactic acid.

The release behavior of insulin from a plasma-irradiated sandwitch (PIS) device using poly-DL-lactic acid (PLA) was studied. The controlled release device can be obtained by oxygen plasma irradiation (radiofrequency discharge operating at 13.56 MHz) on the outer layer of the sandwitch device which was fabricated from an insulin-PLA matrix tablet as a core material and a mixture of plasma-degradable polyoxymethylene (POM) and biodegradable PLA as a wall material. The release test indicated that insulin was released through the micropores formed by the vaporization of POM, and that the release behavior of insulin was affected largely by the molecular weight of PLA used as the outer layer rather than the plasma operational condition. The release of insulin can be controlled by the use of PLA with an average molecular weight of 11000 as the outer layer of the PIS device. Insulin from the PIS device maintained normal blood glucose levels for 10 d in diabetic rats as an implantable dosage form. The duration of insulin effectiveness was relatively short considering the degradation rate of PLA, indicating that the degradation characteristics of biodegradable PLA were not well reflected in the PIS device.

Adsorption↗
PubMedDate not supplied

Experimental studies on an artificial trachea of collagen-coated poly(L-lactic acid) mesh or unwoven cloth combined with a periosteal graft.

Artificial tracheas were fabricated from poly(L-lactic acid) mesh or unwoven cloth coated with collagen in order to reconstruct the respiratory airway by self regeneration without retaining the prosthesis at the replacement site, thus preventing infection, air leakage, granulation tissue formation, and displacement of the prosthesis. Nine weeks after placing a periosteal autologous graft from the tibia around the cervical trachea of a rabbit, bone rings formed without infection. Two weeks after replacement of an 8 X 8 mm window-shaped section of the cervical trachea with autologous periosteum, the internal surface of the trachea was well epithelialized without local complications, but ossification was not seen. One week after cervical substitution with our 2 cm long artificial trachea combined with the periosteal graft, cartilage was produced around the mesh material but neither ossification nor epithelization was observed thereafter, probably due to local infection. On the other hand, cartilage, bone, and epithelium did not form around the unwoven cloth artificial trachea after the substitution, probably because of severe infection due to collapse of the tracheal lumen. However, the formation of bone rings around the trachea suggests preservation of the neotracheal lumen, which may have potential for the treatment of tracheomalacia and/or bronchomalacia.

Animals↗
PubMed1981

Manganese, superoxide dismutase, and oxygen tolerance in some lactic acid bacteria.

A previous study of the aerotolerant bacterium Lactobacillus plantarum, which lacks superoxide dismutase (SOD), demonstrated that it possesses a novel substitute for this defensive enzyme. Thus, L. plantarum contains 20 to 25 mM Mn(II),m in a dialyzable form, which is able to scavenge O2- apparently as effectively as do the micromolar levels of SOD present in most other organisms. This report describes a survey of the lactic acid bacteria. The substitution of millimolar levels of Mn(II) for micromolar levels of SOD is a common occurrence in this group of microorganisms, which contained either SOD or high levels of Mn(II), but not both. Two strains were found which had neither high levels of Mn(II) nor SOD, and they were, as was expected, very oxygen intolerant. Lactic acid bacteria containing SOD grew better aerobically than anaerobically, whereas the organisms containing Mn(II) in place of SOD showed aerobic growth which was best, at best, equal to anaerobic growth. Plumbagin (5-hydroxy-2-methyl-1,4-naphthoquinone) increases the rate of O2- production in these organisms. Lactobacillus strains containing high intracellular Mn(II) were more resistant to the oxygen-dependent toxicity of plumbagin than were strains containing lower levels of Mn(II). The results support the conclusion that a high internal level of Mn(II) provides these organisms with an important defence against endogenous O2-.

Aerobiosis↗
PubMed1991

Effect of plasma glow, glutaraldehyde and carbodiimide treatments on the enzymic degradation of poly (L-lactic acid) and poly (gamma-benzyl-L-glutamate) films.

The hydrolytic and enzymic degradation of poly(L-lactic acid) (PLA) and poly(gamma-benzyl L-glutamate) (PBGA) films, together with a series of surface treatments, were studied, as a function of exposure time. The degradation of these polymers was monitored by weight loss, contact angle, pH changes and tensile strength studies. Glutaraldehyde treatment retained the maximum strength of PLA in buffer, followed by carbodiimide, compared with control films. On the other hand, plasma glow reversed the effect. The ability of alpha-chymotrypsin, carboxypeptidase, ficin, esterase, bromelain and leucine aminopeptidase to modulate the degradation of PLA and PBGA was also investigated. Addition of these enzymes to the polymer-buffer system reduced the tensile strength of these polymers variably. Among the six enzymes studied, leucine aminopeptidase showed the highest enzymic effect on the degradation of the glutaraldehyde-treated and bare PLA or bare PBGA films. However, glutaraldehyde-cross-linked PLA demonstrated maximum stability in buffers or in all other enzyme systems studied compared with bare PLA. It is conceivable that surface treatments on these polymers might have altered their physical and chemical configuration and the subsequent degradation properties. Surface modifications may provide new ways of controlling the biodegradation of polymers for a variety of biomedical applications.

Biocompatible Materials↗
PubMed1999

Colicin V can be produced by lactic acid bacteria.

Colicin V is a small, proteinaceous bacterial toxin, produced by many strains of Escherichia coli and other members of the Enterobacteriaceae, that fits the definition of class II bacteriocins of Gram-positive bacteria. Export of colicin V is dependent on specific ABC (ATP-binding cassette) secretion proteins which recognize a double-glycine-type leader peptide on the immature colicin V bacteriocin. Replacement of the colicin V leader peptide by a signal peptide from the signal sequence-dependent bacteriocin divergicin A allowed expression of colicin V in lactic acid bacteria. This system may serve as a model for the heterologous expression of other small bacteriocins active against Gram-negative bacteria and other antibacterial peptides from lactic acid bacteria.

Bacteriocins↗
PubMedDate not supplied

Self-assembling nanocomplexes from insulin and water-soluble branched polyesters, poly[(vinyl-3-(diethylamino)- propylcarbamate-co-(vinyl acetate)-co-(vinyl alcohol)]-graft- poly(L-lactic acid): a novel carrier for transmucosal delivery of peptides.

The design of carriers for protein delivery that provide protection against enzymatic degradation and facilitate protein transport across epithelial surfaces, thus avoiding parenteral administration, remains a challenge. Self-assembling nanoscale protein/polymer complexes might present a promising approach. We synthesized water-soluble, amphiphilic polyesters, poly[(vinyl-3-(diethylamino)-propylcarbamate-co-(vinyl acetate)-co-(vinyl alcohol)]-graft-poly(L-lactic acid), containing a positively charged backbone, and studied the spontaneous formation of nanocomplexes (NC) with insulin. NC were characterized using dynamic light scattering, zeta-potential measurements, and atomic force microscopy (AFM). Insulin loading was determined with HPLC, and the binding constants were obtained by isothermal titration calorimetry (ITC). The NC formation was followed using nephelometric and light scattering techniques. Water-soluble, positively charged, branched polyesters with amphiphilic properties were obtained in a three-step polymer-analogous reaction. The degree of amine substitution, DS, in the PVAL backbone was varied between 0.04 and 0.5, and grafting this backbone with L-lactide increased the molecular weight from 18 kDa to 81 kDa. The polymer composition was optimized to facilitate NC formation with insulin resulting in a DS of 0.09 and a poly(L-lactide) side chain substitution of 0.5 with an average chain length of two lactic acids. Depending on polymer composition, stable NC of 200-500 nm diameter were formed with insulin, and the binding constants ranged from 4.7 x 10(5) to 9.5 x 10(6) M(-1). Positively charged surface charges ranging from +5 to +35mV and an insulin loading up to 98% of 33 IU/mL were obtained. The NC visualized by AFM revealed spheroidal particles with an entangled internal structure. It was demonstrated that this class of multifunctional polymers is capable of self-assembly with a peptidic substrate. The resulting nanosized complexes offer the potential for mucosal insulin/protein delivery and merit further investigations under in vivo conditions.

Biological Transport↗