Search results for "Lactates"
showing 10 items of 106 documents
Inhibition of tumor lactate oxidation: consequences for the tumor microenvironment.
2011
Abstract Background and purpose Tumor cells are recognized as being highly glycolytic. However, recently it was suggested that lactate produced in hypoxic tumor areas may be taken up by the monocarboxylate transporter MCT1 and oxidized in well-oxygenated tumor parts. Furthermore, it was shown that inhibition of lactate oxidation using the MCT1 inhibitor α-cyano-hydroxycinnamate (CHC) can radio-sensitize tumors possibly by forcing a switch from lactate oxidization to glycolysis in oxygenated cells, which in turn improves tumor oxygenation and indirectly kills radio-resistant hypoxic tumor cells from glucose starvation. Material and methods To provide direct evidence for the existence of a ta…
Potential application of lactic acid bacteria in the biopreservation of red grape from mycotoxigenic fungi
2021
Background Filamentous fungi are the main contamination agent in the viticultural sector. Use of synthetic fungicides is the regular answer to these contaminations. Nevertheless, due to several problems associated with the use of synthetic compounds the industry demands new and safer methods. In the present work, the biopreservation potential of four lactic acid bacteria (LAB) strains was studied against the principal grape contaminant fungi. Results Agar diffusion test evidenced that all four culture-free supernatant (CFS) had antifungal properties against all tested fungi. The Minimum Inhibitory Concentration (MIC) and Minimum Fungicidal Concentration (MFC) test values evidenced that medi…
Suitability of non-glucose-carbohydrates for parenteral nutrition
1975
Postoperative parenteral nutrition can only be optimally effective if the characteristics of post-traumatic metabolism are taken into account. Two main possibilities are discussed for the carbohydrate component of parenteral nutrition during this phase: glucose with high doses of insulin or non-glucose carbohydrates (sugar substitutes) possibly in a suitable combination with glucose. The risks as well as the technical and organisational problems involved in the use of them are discussed and the authors prefer the second of the two alternatives. Possible side effects of non-glucose carbohydrates are pointed out and it is shown how these can be avoided by observing dose guidelines. So far a c…
Mapping and quantification of biomolecules in tumor biopsies using bioluminescence
1996
Quantitative bioluminescence and single-photon imaging have been applied for mapping concentration distributions of metabolites, such as adenosine triphosphate (ATP), glucose and lactate, in biopsies of cervical cancers in patients. Biopsies were taken before a conventional radiation treatment, and a number of clinically relevant data, such as local tumor control, patient survival, metastatic spread and so forth, were documented. There was no correlation between staging or grading and any of the metabolic parameters measured. Local correlations between ATP, glucose and lactate on a pixel-to-pixel basis were generally positive, with respective Spearman's correlation coefficients less in pati…
Regional cerebral blood flow and regional metabolism in cold induced oedema.
1973
24 hours following a cold induced oedema in cats rCBF was measured in the lesion area, the bluish stained cortex immediately adjacent to the lesion, a cortical area remote from the lesion, and in the contralateral uninjured hemisphere. Thereafter the brain was frozen and the respective tissue areas were removed and analyzed for water and electrolyte content as well as metabolite concentrations. It seems, that in the neighbourhood of a local lesion at least 3 different brain regions can be differentiated with regard to their characteristic pattern of data. In non-oedematous regions either hyperaemia or hypoaemia could be observed. In areas with local brain oedema rCBF was reduced inversely p…
Swelling, Acidosis, and Irreversible Damage of Glial Cells from Exposure to Arachidonic Acid in vitro
1994
Swelling and damage of C6 glioma cells and of primary cultured astrocytes were analyzed in vitro during incubation with arachidonic acid (AA; 20:4). The cells were suspended in a physiological medium supplemented with AA at concentrations of 0.001–1.0 m M. Cell swelling was quantified by flow cytometry with hydrodynamic focusing. Flow cytometry was also utilized for assessment of cell viability by exclusion of the fluorescent dye propidium iodide and for measurement of the intracellular pH (pHi) by 2′,7′-bis-(2-carboxyethyl)−5(and −6)carboxyfluorescein. Administration of AA caused an immediate dose-dependent swelling of C6 glioma cells, even at a concentration of 0.01 m M. At this level cel…
Comparative imaging of structure and metabolites in tumours.
1991
A novel technique for metabolic imaging using quantitative bioluminescence and single photon imaging was used to measure the distribution of ATP and lactate in two types of human melanoma xenografts with different radiobiologically hypoxic cell fractions (MF: 45 +/- 17% and EE: 6 +/- 3%; mean +/- SD). The tumours were s.c. grown in nude mice and were used for measurement at volumes of 153-3072 mm3. For metabolic imaging the rapidly frozen tumours were serially sectioned, and each cryosection was brought into contact with a frozen bioluminescent enzyme cocktail using a specially designed glass sandwich system. After thawing section and cocktail the luminescence was started, and light was emi…
Influence of carboxylic acids on the stereospecific nicotinamide adenine dinucleotide-dependent and nicotinamide adenine dinucleotide-independent lac…
1971
Leuconostoc mesenteroides increased its lactic acid production from glucose threefold when malic acid was added to the culture. This increase resulted also in a reduction of the ratio of d -lactic acid to l -lactic acid (31.5 to 1.23). Addition of malic acid increased 6.5-fold the specific activity of nicotinamide adenine dinucleotide (NAD)-linked l -lactate dehydrogenase and increased 3.2-fold that of NAD-linked d -lactate dehydrogenase. The Michaelis constant ( K m ) for NAD of the NAD-linked l -lactate dehydrogenase increased with the addition of malate, but no change was observed in the K m values for the respective d -enzyme. The effect of carboxylic acids on the NAD-linked l -lactate…
Nicotinamide Adenine Dinucleotide-Dependent and Nicotinamide Adenine Dinucleotide-Independent Lactate Dehydrogenases in Homofermentative and Heterofe…
1971
Three homofermentative ( Lactobacillus plantarum B38, L. plantarum B33, Pediococcus pentosaceus B30) and three heterofermentative ( Leuconostoc mesenteroides 39, L. oenos B70, Lactobacillus brevis ) lactic acid bacteria were examined for the presence or absence of nicotinamide adenine dinucleotide (NAD)-dependent and NAD-independent d - and l -lactate dehydrogenases. Two of the six strains investigated, P. pentosaceus and L. oenos , did not exhibit an NAD-independent enzyme activity capable of reducing dichlorophenol indophenol. The p H optima of the lactic dehydrogenases were determined. The NAD-dependent enzymes from homofermentative strains exhibited optima at p H 7.8 to 8.8, whereas va…
Biodegradable tablets having a matrix of low molecular weight poly-L-lactic acid and poly-D,L-lactic acid.
1990
Biodegradable Homo- and Copolymers of lactic and glycolic acids have been used for manufacture of microparticles and matrix implants1,5). To ensure sufficient hydrolytic matrix stability lactic acids of high and medium degree of polymerization have been used. The manufacture of poly lactic acid tablets with an average molecular weight of 25000 and 6000 was reported recently, after finishing the following study2). Bioabbaubare Gerusttabletten aus niedermolekularer poly-L-Milchsaure und poly-D,L-Milchsaure