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Symptomatic elevations of lactic acid and their response to treatment manipulation in human immunodeficiency virus-infected persons: a case series.

Symptomatic lactic acidemia was seen in 5 human immunodeficiency virus-positive patients receiving combination therapy that included stavudine and > or =1 other nucleoside. Peak venous lactic acid levels of 3.1-7.4 mmol/L (normal range, 0.5-2.1 mmol/L) were associated with fatigue and rapid weight loss, whereas withdrawal of antiretrovirals led to normalization of venous lactic acid levels, symptomatic improvement, and weight gain. Resumption of an altered therapeutic regimen, which did not include stavudine but did include other nucleosides in 4 of 5 cases, did not result in recurrence of the syndrome after up to 126 days.

Adult↗

Rapid two point kenetic determination of plasma lactic acid.

1. Plasma levels of L-lactic acid were determined employing a two-point kinetic, lactic dehydrogenase method without a protein free filtrate preparation. 2. The method was characterized with regards to precision, linearity, recovery and accuracy. 3. Regression analyses were accomplished by comparison of the kinetic and standard enzymatic end point procedures. 4. Clinically significant values are obtained within 50% less time than routine methods presently employed.

Adult↗

Habitual intake of lactic acid bacteria and risk reduction of bladder cancer.

INTRODUCTION: A kind of lactic acid bacteria, Lactobacillus casei strain Shirota, shows antitumor activity in experimental animals. One clinical trial using L. casei showed a significant decrease in the recurrence of superficial bladder cancer. So, to assess the preventive effect of the intake of L. casei, widely taken as fermented milk products in Japan, against bladder cancer, we conducted a case-control study. METHODS: A total of 180 cases (mean age: 67 years, SD 10) were selected from 7 hospitals, and 445 population-based controls matched by gender and age were also selected. Interviewers asked them 81 items. The conditional logistic regression was used to estimate adjusted odds ratios (OR). RESULTS: The OR of smoking was 1.61 (95% confidence interval: 1.10-2.36). Those of previous (10-15 years ago) intake of fermented milk products were 0.46 (0.27-0.79) for 1-2 times/week and 0.61 (0.38-0.99) for 3-4 or more times/week, respectively. CONCLUSION: It was strongly suggested that the habitual intake of lactic acid bacteria reduces the risk of bladder cancer.

Aged↗

Effect of toxaphene on pyruvic and lactic acid levels in the rat.

Rats were given a single dose of toxaphene (120 mg/kg equilavent to 1/2 LD50) and sacrificed at 1, 5, and 15 days. No alterations of levels of pyruvic or lactic acid in blood plasma were observed. In a second experiment, rats were given 2.4 mg/kg daily and sacrificed at 1, 3, and 6 months, and again no alterations of pyruvic or lactic acid levels were found. It is concluded that observed alterations of the activity of lactic acid dehydrogenase induced by toxaphene do not give rise to physiological changes in unstressed rats.

Animals↗

Lactic acid bacteria in the treatment of acute rotavirus gastroenteritis.

We compared different lactic acid bacteria for their effect on the immune response to rotavirus in children with acute rotavirus gastroenteritis. After initial oral rehydration, 49 children aged 6 to 35 months with rotavirus gastroenteritis randomly received either Lactobacillus casei subsp. casei strain GG (LGG), L. casei subsp. rhamnosus (Lactophilus), or a combination of Streptococcus thermophilus and L. delbrückii subsp. bulgaricus (Yalacta) twice daily for 5 days. Serum antibodies to rotavirus, total number of immunoglobulin-secreting cells (ISC), and specific antibody-secreting cells (sASC) to rotavirus were measured at the acute stage and at convalescence. The mean (SD) duration of diarrhea was 1.8 (0.8) days in children who received LGG, 2.8 (1.2) days in those receiving Lactophilus, and 2.6 (1.4) days in those receiving Yalacta (F = 3.3, p = 0.04). The ISC response was comparable in the three study groups, but the rotavirus-specific immune responses were different. LGG therapy was associated with an enhancement of IgA sASC to rotavirus and serum IgA antibody level at convalescent stage. We conclude that certain strains of lactic acid bacteria, particularly LGG, promote serum and intestinal immune responses to rotavirus, and thus may be important in establishing immunity against rotavirus reinfections.

Acute Disease↗

The screening of hydrogen peroxide-producing lactic acid bacteria and their application to inactivating psychrotrophic food-borne pathogens.

Lactic acid bacteria were isolated from various food samples and evaluated for hydrogen peroxide (H2O2) production. Cells suspended in 0.5% (wt/vol) glucose plus 0.5% (wt/vol) lactate (pH 7.0) were incubated for 5 h at 37 degrees C under aeration. Among 193 strains, 27 strains accumulated 201-300 ppm H2O2, and 4 strains accumulated more than 301 ppm H2O2 in the cell suspensions. Among the 9 high-level H2O2-producing strains, 8 strains were identified as Lactococcus lactis subsp. lactis. The cell-free filtrate from Lc. lactis subsp. lactis AI 62, which contained approximately 350 ppm H2O2, was evaluated for antimicrobial activity against Enterococcus faecalis, Ent. faecium, enterotoxigenic Escherichia coli, Listeria ivanovii, Staphylococcus aureus, Yersinia enterocolitica, and Aeromonas hydrophila. After 1 h incubation at 30 degrees C in the cell-free filtrate, the initial viable cell counts of the target bacteria (5.53-6.00 log cfu/mL) were reduced by 0.12-5.00 log units, except in the case of enterococci. The sensitivity varied with the bacterial species and pH. The enterococci were resistant to the treatment. Our results show that H2O2 accumulated by lactic acid bacteria in a cell suspension is very effective in reducing the viable cell count of food-borne pathogens.

Aeromonas hydrophila↗

Effect of freeze-dried poly-L-lactic acid discs mixed with bone morphogenetic protein on the healing of rat skull defects.

Porous poly-L-lactic-acid discs were prepared by a freeze-drying method (FDPLLA). During preparation of the discs, semipurified bone morphogenetic protein (BMP) was mixed with the poly-L-lactic acid (500 micrograms BMP per disc). The discs were implanted in the skull defects of rats and retrieved after 2 or 4 weeks. With the FDPLLA/BMP discs, new bone formation was observed at 2 weeks after implantation. On the other hand, plain FDPLLA discs failed to produce new bone formation even at 4 weeks after implantation. Calcium content of the retrieved FDPLLA/BMP discs was statistically higher than that of plain FDPLLA discs. These results suggest that FDPLLA may be an effective delivery system for BMP and that the FDPLLA/BMP disc may potentially have usefulness as a bone graft substitute.

Animals↗

Do intramedullary rods of self-reinforced poly-L-lactide or poly-DL/L-lactide cause lactic acid acidosis in rabbits?

Intramedullary rods of self-reinforced poly-DL/L-lactic acid or poly-L-lactic acid were implanted in both femurs of ten rabbits for 60 weeks. Levels of arterial blood L- and D-lactate, pyruvate, pH, pCO2, base excess, standard bicarbonate, pO2 and O2-saturation were determined before implantation and 1, 3, 6, 12, 24, 36, 48 and 60 weeks after implantation. No significant increase in blood L- and D-lactate level was observed at any follow-up. Also, the blood acid-base balance remained normal throughout the study. Further studies on larger implants and on larger animals with follow-ups up to 5 years are recommended.

Acid-Base Equilibrium↗

Protection against tetanus toxin after intragastric administration of two recombinant lactic acid bacteria: impact of strain viability and in vivo persistence.

Non-pathogenic lactic acid bacteria (LAB) are attractive as live carriers to deliver protective antigens to the mucosal immune system. Both persisting and non-persisting strains of lactic acid bacteria have been evaluated and seem to work equally well by the systemic and nasal routes of administration. However, it is not known if persistence and viability of the strain play a critical role when immunizing by the oral route. To address this question, recombinant LAB strains, able to persist (Lactobacillus plantarum NCIMB8826/pMEC127) or not (Lactococcus lactis MG1363/pMEC46) in the gastro-intestinal tract of mice and producing equivalent amounts of the tetanus toxin fragment C (TTFC) were compared to each other. A very strong ELISA TTFC-specific and protective humoral response was elicited by either live or UV-inactivated recombinant Lb. plantarum strains. In a similar protocol, recombinant Lc. lactis seemed to be somewhat less efficient than the former host. It is thus tempting to propose that the difference in the capacity of the bacterial vector to persist in the gastro-intestinal tract impacts on its immunogenicity and on the level of protection it may induce. Protection was slightly superior after administration of live strains.

Administration, Oral↗

Enhancement of iron-catalyzed free radical formation by acidosis in brain homogenates: differences in effect by lactic acid and CO2.

The influence of lactic acidosis and of extreme hypercapnia on free radical generation and lipid peroxidation in brain tissues was studied. Cortical homogenates were prepared from the rat brain in a bicarbonate buffer and incubated for 60 min. Lipid peroxidation was evaluated by measurements of thiobarbituric acid reactive (TBAR) material and alpha-tocopherol analysis. The pH during incubations were decreased to 6.10-6.20 by either lactic acid administration or equilibration with 60% CO2 gas in paired experiments. In homogenates treated with lactic acid there was a 20-fold increase in TBAR material and the alpha-tocopherol concentration decreased to approximately 60% of control. There was only a 10-fold increase in TBAR material and no change in alpha-tocopherol concentration if acidosis was induced by CO2. These differences between lactic acidosis and hypercapnic acidosis were statistically highly significant. The results indicate that lactic acidosis has a more pronounced effect in augmenting free radical generation in brain tissues than acidosis due to an increase in CO2 tension. It is suggested that this effect of lactic acid is mediated by increased dissociation of catalytic iron from proteins of the transferrin type.

Acidosis, Lactic↗

Electrokinetic removal of chromium and copper from contaminated soils by lactic acid enhancement in the catholyte.

The electrokinetic removal of chromium and copper from contaminated soils by adding lactic acid in cathode chamber as an enhancing reagent was evaluated. Two sets of duplicate experiments with chromium contaminated kaolinite and with a silty soil sampled from a superfund site in California of USA and polluted by Cr and Cu, were carried out in a constant current mode. Changes of soil water content and soil pH before and after the electrokinetic experiments, and variations of voltage drop and electroosmosis flow during the treatments were examined. The results indicated that Cr, spiked as Cr( VI ) in the kaolinite, was accumulated mainly in the anode chamber, and some of Cr and metal hydroxides precipitated in the soil sections in contact with the cathode, which significantly increased electrical energy consumption. Treatment of the soil collected from the site showed accumulation of large amounts of Cr and Cu in the anode chamber while none was detected in the cathode one. The results suggested that the two metals either complexed with the injected lactic acid at the cathode or existed as negatively charged complex, and electromigrated toward the anode under a voltage gradient.

Chromium↗

[Lactic acid bacteria and streptococci of the human stomach normally and in pathological processes].

Lactic acid bacteria were either absent or present in negligent quantities in the stomach of apparently healthy man. But in case of various pathological processes in the stomach and duodenum lactic acid bacteria accumulated (up to a million cells per 1 ml of gastric contents). Under these conditions coccal forms sharply prevailed over the bacillary ones. In patients with chronic gastritis and peptic ulcer of the stomach the most frequent were Streptococcus faecalis and its variants; in oncological patients--Str. faecium, strains affiliated to Leuconostoc mesenteroides, and sometimes Str. durans.

Adult↗

Effect of sodium nitrite and sodium chloride on growth of lactic acid bacteria.

The effect of NaNO2 and NaCl on the growth of 24 lactic acid bacteria strains isolated from vacuum-packed cooked ring sausages were examined by analyzing different growth parameters with Bioscreen. NaNO2 had a very limited effect on the growth of lactic acid bacteria at 50 and 100 mg/l but at 400 mg/l a more pronounced inhibitory effect was found. Bacterial growth was enhanced by 1-2% (w/v) of added NaCl, while NaCl concentrations above 3% (w/v) had a clear inhibitory effect. Leuconostoc isolates seemed to be more sensitive to sodium nitrite and sodium chloride than homofermentative lactobacilli strains. Among homofermentative lactobacilli, the strains resembling Lactobacillus curvatus were more sensitive to NaCl than those resembling Lactobacillus sake.

Animals↗

Immune response to nasal delivery of antigenically intact tetanus toxoid associated with poly(L-lactic acid) microspheres in rats, rabbits and guinea-pigs.

Tetanus toxoid was adsorbed onto poly(L-lactic acid) microspheres. Analyses by sodium dodecyl sulphate-polyacrylamide gel electrophoresis and Western blotting suggest that the formulation procedure does not affect the stability or the antigenic properties of the protein. After nasal administration to guinea-pigs, the resulting preparation enhanced the immune response to the tetanus toxoid when compared with the free antigen. The increase in systemic immunoglobulin G titre was almost immediate in the group treated with the adsorbed tetanus toxoid (time zero, 140; week 2, 1550; week 4, 2760), reaching 36,000 two weeks after the booster (week 7), whereas the free antigen produced an immune response similar to that found in non-treated animals. In a parallel experiment, latex particles of a similar size to poly(L-lactic acid) microspheres, administered to both rats and rabbits, were detected in the blood stream. These findings with tetanus toxoid demonstrate the use of microsphere delivery systems for nasal application of antigens. These had a profound effect on the immune response, and indicate possibilities for overcoming some of the barriers to drug absorption in general.

Administration, Intranasal↗

Efficient production of L-(+)-lactic acid using mycelial cotton-like flocs of Rhizopus oryzae in an air-lift bioreactor.

L-(+)-Lactic acid production was enhanced in a culture of Rhizopus oryzae by induction of a mycelial flocs morphology. By conventional culture the morphology of R. oryzae is that of a pellet-like cake; however, when mineral support and poly(ethylene oxide) are added to the culture, the morphology of R. oryzae takes on a cotton-like appearance. The formation of these cotton-like mycelial flocs was induced by the addition of 5 ppm poly(ethylene oxide) into a 12-14 h culture containing 3 g/L of the mineral support before the formation of the conventional pellet morphology. The cotton-like flocs were also formed in cultures grown in an air-lift bioreactor. This morphology allowed effective mass transfer inside the flocs and effective fluidity of culture broth in an air-lift bioreactor. L-(+)-Lactic acid concentration produced by mycelial flocs in an air-lift bioreactor, with the support and poly(ethylene oxide), was 104.6 g/L with a yield of 0.87 using 120 g/L of glucose as the substrate; for this culture without both, the concentration was 43.2 g/L. These results demonstrate that cotton-like mycelial flocs are the optimal morphology for use in the air-lift bioreactor culture of R. oryzae.

Bioreactors↗

Genetic organization and expression of citrate permease in lactic acid bacteria.

Citrate is present in many natural substrates, such as milk, vegetables and fruits, and its metabolism by lactic acid bacteria (LAB) plays an important role in food fermentation. The industrial importance of LAB stems mainly from their ability to convert carbohydrates into lactic acid and, in some species, like Lactococcus lactis and Leuconostoc mesenteroides, to produce C4 flavor compounds (diacetyl, acetoin) through citrate metabolism. Three types of genetic organization and gene locations, involving citrate metabolism, have been found in LAB. Citrate uptake is mediated by a citrate permease, which leads to a membrane potential upon electrogenic exchange of divalent citrate and monovalent lactate. The internal citrate is cleaved into acetate and oxaloacetate by a citrate lyase, and oxaloacetate is decarboxylated into pyruvate by an oxaloacetate decarboxylase, yielding a pH gradient through the consumption of scalar protons.

Bacterial Proteins↗

The transport of oxygen, glucose, carbon dioxide and lactic acid in the human brain: mathematical models.

Mathematical models of the transport of oxygen, glucose, carbon dioxide and lactic acid in the human brain have been developed and solved for both steady-state and dynamic cases which include normal conditions, arterial and venous hypoxia, reduced flow and hematocrit, hypocapnia, reduced glucose and transient arterial upsets. Results indicate that local concentration deficits of oxygen and/or glucose and excesses of lactic acid can exist within the system described by the models and therefore possibly could exist in the tissues of the human brain under similar conditions.

Biological Transport, Active↗

Mechanisms of fatigue-induced activation of group IV muscle afferents: the roles played by lactic acid and inflammatory mediators.

We already showed that group IV muscle afferents are activated during electrically-induced fatigue. The purpose of this study is to identify the mechanisms of stimulation of these muscle afferents by electrically-induced fatigue at a high (100 Hz; high frequency fatigue, HFF) or a low rate (10 Hz; low frequency fatigue, LFF) of stimulation. In 23 paralyzed and anaesthetized rabbits, group IV afferent activity from the tibialis anterior muscle was recorded before and after 3-min HFF or 5-min LFF runs eliciting the same force failure. Plasma lactic acid concentration (LA) was also measured in leg venous blood. We tested the effects of dichloroacetate (DCA), which reduces lactic acid production, and of acetylsalicylic acid (ASA), a blocker of cyclooxygenase, on fatigue-induced activation of group IV muscle afferents after HFF and LFF trials. Pretreatment by ASA or DCA did not modify HFF-induced activation of muscle afferents. On the other hand, LFF-induced response was markedly depressed by each pharmacological agent (-44% after ASA and -75% after DCA). We verified that DCA markedly lowered LA production after LFF. The present results show that the activation of group IV muscle afferents by LFF or HFF results from different mechanisms and also demonstrate the major role played by lactic acid production and, to a lesser extent, the release of inflammatory mediators in LFF-induced activation of group IV muscle afferents.

Animals↗