Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

Query: EC:1.1.1.27 (lactate dehydrogenase)
29,211 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Peritonitis remains a major problem in peritoneal dialysis. The incidence of peritonitis may be reduced by the use of more "biocompatible" peritoneal dialysis solutions that do not impair local host defense mechanisms, such as occurs with conventional lactate-buffered glucose solutions. In the present study, we investigated the use of bicarbonate and lactate as buffer systems and glucose, amino acids, and glucose polymer as osmotic agents on specific cellular functions of isolated fresh blood monocytes in vitro. The bicarbonate-buffered solutions had a physiologic pH (7.0 to 7.6). Lactate-buffered solutions were tested with a pH between 5.5 and 7.3. RPMI 1640 (Roswell Park Memorial Institute, supplied by Biochrom, Berlin, Germany) and phosphate-buffered saline were used as control mediums. The test solutions were incubated with 200,000 monocytes/mL for 45 minutes followed by a 1:1 mix with RPMI 1640 (with supplements) during a 24- or 4-hour tetrazolium bromide test (MTT test) recovery period. Constitutive and lipopolysaccharide (LPS)-stimulated release of interleukin-1beta (IL-1beta) and IL-6 in the supernatants as parameters of cellular host defense and lactate dehydrogenase concentrations and MTT-formazan production as parameters for cell cytotoxicity were measured. Significantly higher IL-6 and IL-1beta release was found in the bicarbonate-buffered solutions, both under basal conditions and after LPS stimulation, compared with the lactate-buffered solutions (LPS stimulation: 1% amino acids/34 mmol/L bicarbonate, IL-1beta: 1,166 +/- 192 pg/mL; 1.5% glucose/34 mmol/L bicarbonate, IL-1beta: 752 +/- 107 pg/mL; 1.5% glucose/35 mmol/L lactate/pH 5.5, IL-1beta: 174 +/- 51 pg/mL). Some of these differences could even be detected in spent dialysate after a 6-hour dwell in continuous ambulatory peritoneal dialysis patients (n = 10). A lower degree of cellular cytotoxicity (lactate dehydrogenase activity) and better-preserved metabolic activity (MTT test) also were found for the bicarbonate-buffered solutions. Amino acids (1%) proved to be comparable to glucose (1.5%) as an osmotic agent at a neutral pH with regard to LPS-stimulated cytokine release and cytotoxicity. The incubation with a glucose polymer solution (7.5% glucose polymer in phosphate-buffered saline, pH 7.3) resulted in a significantly lowered cytokine release (LPS stimulation: IL-1beta, 69 +/- 19 pg/mL) compared with the other solutions with neutral pH (P < 0.01). These results suggest that bicarbonate as a buffer provided better biocompatibility with regard to mononuclear cytokine release and viability compared with lactate. Amino acids and glucose were equivalent to these parameters at a physiologic pH. The glucose polymer solution, however, was associated with a marked depression of cytokine release.
...
PMID:Osmotic agents and buffers in peritoneal dialysis solution: monocyte cytokine release and in vitro cytotoxicity. 929 71

1. The effects of quercetin on drug metabolising enzymes and oxygen radicals were studied in human HepG2 cells. 2. Cytotoxicity of quercetin in HepG2 cells was seen at 50 microM and above as evaluated by lactate dehydrogenase (LDH) leakage, neutral red (NR) uptake, and 3-(4,5-dimethyl-thiazol-2yl)-2,5-diphenyl tetrazolium bromide (MTT) reduction. 3. Quercetin inhibited activity of human cytochrome P-450 towards ethoxycoumarin and ethylresorufin at relatively low substrate concentrations (0.1 microM and above). 4. In comparison to induction by the positive control (beta-naphthoflavone; 1.0 microM), quercetin did not significantly induce the metabolism of ethoxycoumarin or glutathione-S-transferase (GST) protein or activity. 5. Response elements for human CYP1A1, GST lambda a, xenobiotic response element (XRE), fos, HSP70, CRE, p53, NF kappa B and DNA damage (GADD) in HepG2 cells were not activated by quercetin. 6. Quercetin exhibited antioxidant activity in HepG2 cells as evidenced by its ability to inhibit the oxidation of the fluorochrome dichlorofluorescin. 7. The results indicate a range of potential beneficial effects of quercetin with respect to the influence on carcinogen-metabolising enzymes, scavenging of reactive oxygen species and a lack of stress response in HepG2 cells.
...
PMID:Effects of quercetin on drug metabolizing enzymes and oxidation of 2',7-dichlorofluorescin in HepG2 cells. 942 83

The progressive responses to photodynamic treatment (lambda > 590 nm) mediated by Temoporfin have been investigated in vitro on two rodent cell lines: BHK and murine hepatoma MH22 cells. Comparisons are made of two light exposure/post-exposure incubation media: Dulbecco's minimal essential medium (DMEM) and phosphate-buffered saline (DPBS) depleted of energy sources. Enhancement of lipid peroxidation is an early response to Temoporfin photosensitization in either experimental set. It is restored to the initial level by subsequent incubation in DMEM, but not in DPBS. The decrease in MTT specific activity and especially lactate dehydrogenase leakage from the cells are faster in DPBS and continue to proceed during the post-exposure incubation in the both media. The intracellular ATP pool is completely depleted within 3 h of post-exposure incubation in DPBS, but not in DMEM where, in contrast, an initial increase in ATP is observed. Based on these preliminary observations, it is presumed that ATP synthesized by injured mitochondria and activated glycolysis is being used to restore the deteriorated cell functions and/or to allow reactions involved in apoptosis to proceed.
...
PMID:Post-exposure processes in Temoporfin-photosensitized cells in vitro: reliance on energy metabolism. 944 Mar 23

Recent studies suggest that Alzheimer's disease and non-insulin-dependent (type 2) diabetes mellitus may share a common cell death mechanism, related to the toxicity of beta-amyloid (Abeta) and amylin, respectively. Both Abeta and amylin cause apoptosis in different cell culture systems, which may be related to the amyloidogenic properties of these peptides. We have further characterized the actions of a variety of Abeta peptides (Abeta25-35, Abeta1-40, Abeta1-42), human amylin and rat amylin (which does not form fibrils) on undifferentiated PC12 cells. Although all peptides except rat amylin compromised mitochondrial function as assessed by MTT reduction, only human amylin decreased cell viability at a concentration of 10 microM, as measured by lactate dehydrogenase release or trypan blue exclusion assay. The cell death caused by human amylin was determined to be predominantly of an apoptotic nature, with a possibility of a portion of necrotic cell death, which was not accompanied by increased expression of c-Jun or c-Fos inducible transcription factors.
...
PMID:Acute application of human amylin, unlike beta-amyloid peptides, kills undifferentiated PC12 cells by apoptosis. 946 71

Oxygen radical injury and lipid peroxidation have been suggested as major causes of cancer, atherosclerosis and the aging process. We examined in vitro the effect of garlic on H2O2-induced oxidant injury in bovine pulmonary artery endothelial cells (PAEC). After overnight preincubation with Aged Garlic Extract (AGE, from Wakunaga Pharmaceutical Co., Ltd., Japan) or S-allyl cysteine (SAC), PAEC monolayers were exposed to H2O2 for 3 h. Cell viability (MTT assay), lactate dehydrogenase (LDH) release, and lipid peroxidation (TBA-RS) were measured to assess oxidant injury. AGE (1-4 mg/ml) pretreatment significantly reduced the loss of cell viability induced by 50-100 microM of H2O2. AGE and SAC exhibited dose dependent inhibition of both LDH release and TBA-RS production induced by 50 microM of H2O2. The results show that AGE and SAC can protect vascular endothelial cells from oxidant injury. Numerous garlic compounds could be involved in the antioxidant properties of garlic, while there could be some prooxidant compounds derived from garlic. It is important to keep an array of antioxidant compounds to develop good herbal preparation, like AGE.
...
PMID:[Garlic compounds protect vascular endothelial cells from oxidant injury]. 950 21

The diet and nutritional status dominate a tolerance to environmental xenobiotics. In this study, the cytotoxic action of carbon tetrachloride (CCl4) and 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1), one of the dietary carcinogens, was investigated using primary cultured hepatocytes from rats fed a high-fat (23% corn oil) or high-protein (50% casein) diet for three weeks. Both chemicals showed strong cytotoxicity to hepatocytes, which was judged by measurement with the MTT-test and lactate dehydrogenase leakage test. A dietary effect on cytotoxicity was observed; hepatocytes from rats fed the high-protein diet were more susceptible to cytotoxicity than the cells from rats fed a standard diet. On the other hand, ureogenesis, as a cellular function of hepatocytes, was markedly decreased in the cells from rats fed the high-fat diet. These activities were affected in the CCl4-treated cells but not in the Trp-P-1-treated cells. The same trend of both diet and chemical effects was observed in gluconeogenesis from fructose. We conclude that the hepatocytes from rats fed a high-protein diet have high susceptibility to the cytotoxicity of CCl4 and Trp-P-1, but cytotoxicity was not related to the reduction of cellular functions.
...
PMID:Xenobiotic tolerance of primary cultured hepatocytes in rats fed a high-fat or high-protein diet. 959 Dec 37

Apoptosis, or programmed cell death, is a physiological form of cell death that plays a critical role in the development and maintenance of multicellular organisms. Apoptosis is characterized based on morphological and biochemical criteria. Morphological characteristics include cell shrinkage, cytoplasmic condensation, chromatin segregation and condensation, membrane blebbing, and the formation of membrane-bound apoptotic bodies, whereas the biochemical hallmark of apoptosis is internucleosomal DNA cleavage into oligonucleosome-length fragments. A great deal of research is aimed at defining the molecular mechanisms that play a role in apoptosis. As one of the common end points of experiments related to apoptosis is in fact the death of the cell, it has become important to develop reliable assays to measure cell death that may be compared among the various systems being investigated. This chapter reviews many of the current methods used to measure apoptotic cell death and points out strengths and weaknesses of each approach with respect to the system being examined and the questions being asked. Traditional cell-based methods, including light and electron microscopy, vital dyes, and nuclear stains, are described. Biochemical methods such as DNA laddering, lactate dehydrogenase enzyme release, and MTT/XTT enzyme activity are described as well. Additionally, terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling of DNA fragments (TUNEL) and in situ end labeling (ISEL) techniques are reviewed, which when used in conjunction with standard flow cytometric staining methods may yield informative data relating cell death to various cellular parameters, including cell cycle and cell phenotype. The use of one or more of the methods described in this chapter for measuring cell death should enable investigators to accurately assess apoptosis in the context of the various models being examined and help define causal relationships between the mechanisms that regulate apoptosis and the cell death event itself.
...
PMID:Measurement of cell death. 964 9

In this study, we analyzed the influence of vitamin E succinate (5-80 microM), supplemented in the culture medium, on the survival of cultured retinal cells. The release of lactate dehydrogenase (LDH) was decreased in the presence of low concentrations (10-20 microM) of vitamin E succinate, whereas high concentrations (80 microM) induced a significant increase (about 2-fold) in the release of LDH, indicating a reduction of plasma membrane integrity. Supplementing with vitamin E succinate (80 microM) greatly enhanced its cellular content, as compared to vitamin E acetate (80 microM), and the membrane order of the retinal cells, as evaluated by the fluorescence anisotropy (r) of TMA-DPH (1-(4-(trimethylammonium)-phenyl)-6-phenylhexa-1,3,5-triene), was not altered. Furthermore, vitamin E succinate was more potent than vitamin E acetate in reducing thiobarbituric acid reactive substances (TBARS) formation upon ascorbate-Fe2+-induced oxidative stress (TBARS formation after cell oxidation decreased by about 15-fold or 1.6 fold, respectively, in the presence of 20 microM vitamin E succinate or 20 microM vitamin E acetate). A decrease in MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) reduction induced by supplementing with vitamin E succinate (80 microM), to 35.99 +/- 1.96% as compared to the control, but not by vitamin E acetate (80 microM), suggests that vitamin E succinate may affect the mitochondrial activity. Vitamin E succinate also reduced significantly the ATP:ADP ratio in a dose-dependent manner, indicating that vitamin E succinate-mediated cytotoxic effects involve a decrement of mitochondrial function.
...
PMID:Influence of vitamin E succinate on retinal cell survival. 971 Jan 52

The target of this research was to determine the cytotoxicity of sodium laurylsulfate on single-layer cultures of human fibroblasts, using two colorimetric methods (neutral red and MTT tests) and the evaluation of the pyruvic acid consumption by the cells. For the determination of the cytotoxicity by colorimetric tests, we have determined the absorbance at 540 nm using a spectrophotometer. Pyruvic acid, present in the culture medium, is the mitochondria's C3 energetic metabolite. So, a measure of the cell's consumption of pyruvic acid was developed. The reaction is as follows: Pyruvic acid + NADH --> Lactic acid + NAD+ and the enzyme employed is the LDH (lactate dehydrogenase). This method can be used to measure cytotoxicity, proliferation, and the cell's activation. The method is rapid, precise, and lacks any toxic byproduct. The absorbance was measured using a spectrophotometer at 340 nm. The consumption of pyruvic acid follows upon the fibroblast's growth. Sodium laurylsulfate cytotoxicity test after 24 h shows that the NR colorimetric test and the pyruvic acid consumption are correctly correlated (r = 0.91, alpha = 0.05). This dosage can be used to study the barrier properties of the corneocyte layer without destroying the artificial skin.
...
PMID:In vitro correlation between two colorimetric assays and the pyruvic acid consumption by fibroblasts cultured to determine the sodium laurylsulfate cytotoxicity. 974 88

Immunomodulatory activities of constituents isolated from Hydrangeae Dulcis Folium and their related compounds on lymphocyte proliferation were investigated using splenocytes and lymph node cells. Thunberginol A (TA) significantly suppressed B lymphocyte proliferation stimulated by lipopolysaccharide (LPS) at 10(-5) M. However TA at a lower concentration (10(-6) M) and the other compounds, except hydrangenol and 3'-hydroxyhydrangeaic acid, tended to potentiate B lymphocytes proliferation (10(-5) M). On the other hand, thunberginol A significantly suppressed T lymphocyte proliferation stimulated by concanavalin A (Con A), but did not suppress phytohemagglutinin (PHA). Hydrocortisone and cyclosporin A strongly suppressed T lymphocyte proliferation induced by both Con A and PHA. These results suggest that thunberginol A acts on both B and T lymphocytes and may have a suppressive mechanism different from the known immunosuppressants. The cytotoxicity of TA for splenocytes seemed weaker than known immunosuppressants resulting from viability tests using MTT assay and the measurement of lactate dehydrogenase (LDH) released in the medium. Moreover, TA suppressed antigen-specific T lymphocyte proliferation in mice lymph node cells immunized with keyhole limpet hemocyanin (KLH). Thus, these findings show that TA has a suppressive effect on lymphocyte activation, and this inhibitory effect of TA seems to contribute to its suppressive effect on type IV allergies.
...
PMID:Development of bioactive functions in Hydrangeae Dulcis Folium. VII. Immunomodulatory activities of thunberginol A and related compounds on lymphocyte proliferation. 974 47


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>

---