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At least 307 records · Page 17Linked to original sources
PubMed2006

A protocol for facial volume restoration with poly-L-lactic acid.

Poly-L-lactic acid is a biodegradable synthetic polymer used in an injectable form for subcutaneous volume restoration. Volumetric correction following subcutaneous and deep dermal injection of poly-L-lactic acid is thought to occur through a foreign body tissue response leading to increased production of fibroblasts and subsequent neocollagenesis. Despite the growing popularity and use of this material, there has been a scarcity of published information describing proper injection technique, and many practitioners remain unfamiliar with its use. Appropriate injection technique is critical since incorrect placement of the material can lead to long-lasting unintended results. We present a protocol for successful injection of poly-L-lactic acid into the submalar and buccal regions.

Biocompatible Materials↗
PubMedDate not supplied

Preparation of multi-phase microspheres of poly(D,L-lactic acid) and poly(D,L-lactic-co-glycolic acid) containing a W/O emulsion by a multiple emulsion solvent evaporation technique.

Multi-phase microspheres of poly(D,L-lactic acid) (PLA) or poly(D,L-lactic-co-glycolic acid) (PLGA) containing a water-in-oil (W/O) emulsion were prepared by a multiple emulsion solvent evaporation technique. Acetonitrile was used as the solvent for the polymers and light mineral oil as the dispersion medium for the encapsulation procedure. Process and formulation parameters to optimize the microencapsulation of a W/O emulsion containing water-soluble drugs were investigated. Drug loading efficiencies of 80-100 per cent were obtained under specific preparative conditions. The drug loading efficiency in the microspheres was dependent upon the ratio of the W/O emulsion to polymer and the concentration of surfactant in the mineral oil. Compared to conventional microspheres, in which fine drug particles are homogeneously dispersed in the polymer beads, the multi-phase microspheres permit the higher encapsulation efficiency of water-soluble drugs and eliminate partitioning into the polymer-acetonitrile phase which results in low encapsulation efficiency with conventional solvent evaporation techniques.

Acetonitriles↗
PubMed1995

Determination of lactic acid and pyruvic acid in serum and cerebrospinal fluid by ion-exclusion chromatography with a bulk acoustic wave detector.

A chromatographic method base don a combination of ion-exclusion chromatography separation and bulk acoustic wave series piezoelectric quartz crystal detector quantification for the determination of pyruvic acid and lactic acid in serum and cerebrospinal fluid (CSF) was developed. The separation was carried out using a Shim-pak SCR-102H ion-exclusion column with phosphoric acid solution as eluent. The method shows an acceptable detection limit and anti-interference ability. Serum and CSF from healthy individuals and patient were analysed successfully.

Acoustics↗
PubMed2000

[Hepatotoxicity induction in mice after acute DL-lactic acid intake].

DL-Lactic acid and its salts are added to food as acidulants, pH control agents, leavening agents, nutrient supplements and seasonings. However, the basic data concerning the safety and toxicity of these compounds are insufficient. In this article, we examined induction of hepatotoxicity and nephrotoxicity in mice after acute intake of DL-lactic acid. Body weight change, serum glutamic pyruvic transaminase (SGPT) activity, serum urea nitrogen (SUN) concentration, liver and kidney weights, and renal lipid peroxide level could not be affected significantly in mice at 4 h after intraperitoneal administration of DL-lactic acid at 1.2 mmol/kg, indicating no induction of toxicity in the liver and kidney. In contrast, at 20 h after the treatment, SGPT activity, liver weight and lipid peroxide level were enhanced significantly, suggesting induction of hepatotoxicity. However, SUN concentration, kidney weight and lipid peroxide level could not be affected significantly at 20 h after the treatment, indicating no induction of nephrotoxicity.

Administration, Oral↗
PubMed1977

[Gas chromatographic determination of the volatile fatty acids (C1-C5) including lactic acid after conversion into their benzyl esters by phenyldiazomethane. Determination of the acids in silages (author's transl)].

A gas chromatographic method for the determination of the volatile fatty acids (C1-C5) including lactic acid is described. The acids are converted into their benzyl esters by means of phenyldiazomethane without previous purification of the reagent by distillation. The benzyl esters are well separated from the solvent as well as from one another. Silicone SE-30 is used as the stationary phase. An application of the method on silage acids is demonstrated.

Animal Feed↗
PubMed1998

The contribution of lactic acid to acidification of tumours: studies of variant cells lacking lactate dehydrogenase.

Solid tumours develop an acidic extracellular environment with high concentration of lactic acid, and lactic acid produced by glycolysis has been assumed to be the major cause of tumour acidity. Experiments using lactate dehydrogenase (LDH)-deficient ras-transfected Chinese hamster ovarian cells have been undertaken to address directly the hypothesis that lactic acid production is responsible for tumour acidification. The variant cells produce negligible quantities of lactic acid and consume minimal amounts of glucose compared with parental cells. Lactate-producing parental cells acidified lightly-buffered medium but variant cells did not. Tumours derived from parental and variant cells implanted into nude mice were found to have mean values of extracellular pH (pHe) of 7.03 +/- 0.03 and 7.03 +/- 0.05, respectively, both of which were significantly lower than that of normal muscle (pHe = 7.43 +/- 0.03; P < 0.001). Lactic acid concentration in variant tumours (450 +/- 90 microg g(-1) wet weight) was much lower than that in parental tumours (1880 +/- 140 microg/g(-1)) and similar to that in serum (400 +/- 35 microg/g(-1)). These data show discordance between mean levels of pHe and lactate content in tumours; the results support those of Newell et al (1993) and suggest that the production of lactic acid via glycolysis causes acidification of culture medium, but is not the only mechanism, and is probably not the major mechanism responsible for the development of an acidic environment within solid tumours.

Animals↗
PubMed2006

Production of yogurt with enhanced levels of gamma-aminobutyric acid and valuable nutrients using lactic acid bacteria and germinated soybean extract.

Yogurt with high levels of gamma-aminobutyric acid (GABA), free amino acids and isoflavones was developed using lactic acid bacteria (LAB) and germinated soybean extract. Fermented soya milk (GABA soya yogurt) produced with starter and substrate had the GABA concentration of 424.67 microg/gDW, whereas fermented milk produced by a conventional method had GABA less than 1.5 microg/gDW. The GABA soya yogurt also contained significantly high levels of free amino acids and isoflavones compared with other conventional yogurts. The results suggested that the Lactobacillus brevis OPY-1 and germinated soybean possessed a prospect to be applied in dairy and other health products with high nutritive values and functional properties.

Amino Acids↗
PubMed2006

Effect of bile acid on the cell membrane functionality of lactic acid bacteria for oral administration.

Lactic acid bacteria and other species dwelling in the gut must be tolerant to bile salts. This study sought to determine the effects of the bile salts taurodeoxycholate (TDCA) and deoxycholate (DCA) on Lactobacillus reuteri CRL 1098, a strain of likely probiotic value. When compared to other lactobacilli, L. reuteri showed the highest survival rate but remained sensitive to high (>3 mM) DCA concentrations. DCA produced complete permeabilization of cells, abolished glucose uptake and severely distorted the cell envelope, as shown by electron microscopy. Detailed analytical studies revealed a change in the phospholipid to glycolipid ratio, and also in lipid proportions. The C18:1 W9C form remarkably increased, possibly following a rapid adaptive response during DCA treatment. This study provides the first solid evidence of the mechanism of DCA toxicity in a lactic acid bacterium.

Cell Membrane↗
PubMed1992

[The role of lactic acid bacteria in nutrition and health].

Lactic acid bacteria possess both positive as well as negative aspects in relation to health. On the one side metabolic activities such as the production of extracellular polysaccharides or lactic acid from carbohydrates, are responsible for plaque formation and demineralisation of enamel. On the other hand, further down in the digestive tract, these groups of micro-organisms can have a beneficial effect by locally influencing the microbial composition, specific metabolic activities or stimulation of the immune response. Lactic acid bacteria also play a major role in food preservation. When plants or animals become food after harvesting or slaughter, endogenous resistance mechanisms such as the immune systems are lost and consequently foods become susceptible to spoilage. Food spoilage can be retarded or prevented by application of certain external factors; for example, storage at low temperatures of fermentation by lactic acid bacteria. Similarly, the mature dentition also consist of non-living tissue and is therefore also subject to 'spoilage' (decay). Lactic acid bacteria now play a negative role. However, the metabolism of lactic acid bacteria in plaque and consequently de- and remineralisation may also be influenced by application of external factors as diet, oral hygiene and fluorides. This paper will discuss the functional similarities and differences of lactic acid bacteria in different areas of the digestive tract.

Dental Caries↗
PubMed1997

Fate of low temperature and acid-adapted Yersinia enterocolitica and Listeria monocytogenes that contaminate lactic acid decontaminated meat during chill storage.

Pathogens found in the environment of abattoirs may become adapted to lactic acid used to decontaminate meat. Such organisms are more acid tolerant than non-adapted parents and can contaminate meat after lactic acid decontamination (LAD). The fate of acid-adapted Yersinia enterocolitica and Listeria monocytogenes, inoculated on skin surface of pork bellies 2 h after LAD, was examined during chilled storage. LAD included dipping in 1%, 2% or 5% lactic acid solutions at 55 degrees C for 120 s. LAD brought about sharp reductions in meat surface pH, but these recovered with time after LAD at approximately equal to 1-1.5 pH units below that of water-treated controls. Growth permitting pH at 4.8-5.2 was reached after 1% LAD in less than 0.5 d (pH 4.8-5.0), 2% LAD within 1.5 d (pH 4.9-5.1) and after 5% LAD (pH 5.0-5.2) within 4 d. During the lag on 2% LAD meat Y. enterocolitica counts decreased by 0.9 log10 cfu per cm2 and on 5% LAD the reduction was more than 1.4 log10 cfu per cm2. The reductions in L. monocytogenes were about a third of those in Y. enterocolitica. On 1% LAD the counts of both pathogens did not decrease significantly. The generation times of Y. enterocolitica and L. monocytogenes on 2-5% LAD meats were by up to twofold longer than on water-treated controls and on 1% LAD-treated meat they were similar to those on water-treated controls. Low temperature and acid-adapted L. monocytogenes and Y. enterocolitica that contaminate skin surface after hot 2-5% LAD did not cause an increased health hazard, although the number of Gram-negative spoilage organisms were drastically reduced by hot 2-5% LAD and intrinsic (lactic acid content, pH) conditions were created that may benefit the survival and the growth of acid-adapted organisms.

Drug Resistance, Microbial↗
PubMedDate not supplied

In-vivo degradation of poly(lactic acid) of different molecular weights.

Lactic acid was polymerized using tetraphenyl tin as a catalyst. The molecular weight of the resultant poly(lactic acid) varied between 0.89 X 10(6) and 2.94 X 10(6) depending upon the concentration of the catalyst used. In-vivo degradation of the poly(lactic acid) samples having 4 different molecular weights were studies by implanting these in Wistar rats. It was found that at the end of a 48-week implantation period lower molecular weight poly(lactic acid) samples were degraded at a faster rate than the higher molecular weight samples.

Animals↗