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Dunn, C. R., Banfield, M. J., Barker, J. J., Higham, C. W., Moreton, K. M., Turgut-Balik, D., Brady, R. L., Holbrook, J. J. (1996) The structure of lactate dehydrogenase from Plasmodium falciparum reveals a new

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significant difference in creatine kinase and lactate dehydrogenase enzyme activity after 3 sets and 10 repetitions. Given that even if the total number of eccentric contractions in a similar exercise is similar, the magnitude of muscle damage is likely to

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Acta Physiologica Hungarica
Authors:
J Dudka
,
F Burda
,
Barbara Madej
,
Justyna Szumilo
,
Edyta Tokarska
,
Agnieszka Korobowicz
,
R Klepacz
,
Monika ChyüyÅska
, and
Elżbieta Korobowicz

Metabolic acidosis complicates methanol, ethylene glycol and other alcohol intoxications. It is caused firstly by acid metabolites and secondly by the lactate elevation. The aim of the study was to evaluate the effect of alcohol dehydrogenase (ADH; EC 1.1.1.1) inhibitors and substrates: 4-methylpyrazole (4-MP), cimetidine, EDTA, ethanol and methanol on lactate dehydrogenase (LDH; EC 1.1.1.27) activity. The activity of LDH was determined spectrophotometrically in in vitro human heart homogenates with the mentioned compounds at 0.01, 0.1, 1.0 mM concentrations of 4-MP, cimetidine, EDTA, and 12.5, 25.0, 50.0 mM of ethanol and methanol. The LDH activity was significantly inhibited by 0.1 mM (p<0.05) and 1.0 mM (p<0.01) 4-MP and 1.00 mM EDTA (p<0.05). Higher LDH activity vs. control was observed in the samples incubated with all studied ethanol and methanol concentrations but these differences were not statistically significant. Thus, 4-MP was found to be the most effective inhibitor of LDH of all compounds tested. Therefore, such effect of 4-MP seems to be an additional advantage in methanol and ethylene glycol intoxications.

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Abstract  

Radioimmunoassays (RIA) for the determination of the individual lactate dehydrogenase (LDH) isoenzymes, LDH-1 and LDH-2 have been developed. LDH-1 can be measured in the range of 5–100 ng and LDH-2 in the range of 5–80 ng, if there is no significant cross reactivity. Immunization of several rabbits with LDH-1 and LDH-2 isoenzymes reveals that some animals do not produce antisera to LDH-2 while those injected with LDH-1 generated antiserum in each case. The results of the binding studies suggest that a 50% binding that is recommended for RIA can be achieved with a titer value of 12000 dilution of the antisera. Cross reactivity studies indicate that LDH-1 cross reacts with the antisera to LDH-2 if its concentration is higher than 30 ng/ml of the RIA mixture while LDH-2 cross reacts with the antisera to LDH-1 only if its concentration exceeds 80 ng/ml.

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Abstract  

The iodination of lactate dehydrogenase isoenzymes which has not been attempted so far has been performed using radioactive and inactive iodine. A new method for the determination of trace amounts of protein-bound iodine in the range of 10–100 μg has been developed. Out of two methods employed for iodination, chloramine-T method was found to be superior to the lactoperoxidase method for iodination with both radioactive and inactive iodine. It was found that the amount of iodinated LDH formed during iodination depends on the amount of LDH and of the reagents used for iodination. Completely purified LHD-1 and LDH-2 isoenzymes were iodinated using both inactive and radioactive iodine. The iodinated isoenzymes were separated from the unreacted iodide by gel permeation chromatography using Sephadex G-75-120 column. The ratio of radioiodinated LDH to unreacted125I was largest (3.72) when the amount of LDH used was 4.54 μg. The specific activity obtained when iodination was carried out under optimum conditions was 238 μCi/μg. No radiation damage for the radioiodinated LDH was observed when it is kept for as long as two weeks after iodination.

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References 1 Miao P, Sheng S, Sun X, et al. Lactate dehydrogenase A in cancer: a promising target for diagnosis and therapy. IUBMB Life 2013; 65: 904

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The aims of the present study were to: (1) investigate the effect of a weightlifting training session and time-of-day (TOD) upon biological parameters (i.e., oral temperature, hematological, C-reactive protein (CRP), and oxidative stress) and (2) assess their possible link with muscle damage responses. Nine weightlifters (21 ± 0.5 years) performed, in a randomized order, three Olympic-Weightlifting sessions (i.e., at 08:00, 14:00, and 18:00). Blood samples were collected at rest, 3 min and 48 h after each training session. Between pre- and post-training session, ANOVA showed significant increases in oxidative stress markers at the three TODs (p < 0.01) and significant increases for creatine kinase (CK) and lactate dehydrogenase (LDH) only at 08:00 and 18:00 (p < 0.05). At rest, the results showed a significant diurnal variation for the majority of the selected parameters except for malondialdehyde (MDA), total bilirubin, and CRP with higher values observed at 18:00 (p < 0.05). After the training session, given the higher rate of increase during the morning session, these diurnal variations persisted for temperature and WBC (p < 0.01) and were suppressed for CK, LDH, uric acid (UA), catalase, and glutathione peroxidase. The main significant correlations (p < 0.001) were observed between: (1) CK and MDA (r = 0.6) and CK and UA (r = 0.66 and r = 0.82) during the morning and evening training sessions; (2) CK and CRP only during the morning session (r = 0.5); and (3) CRP and WBC during the three training sessions (r = 0.8). In conclusion, the present findings: (1) confirm that the muscle damage responses could be induced by a high level of oxidative stress and (2) suggest to avoid scheduling training sessions in the morning given the higher muscle damage, inflammatory, and oxidative responses at this TOD.

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This study compared two training regimens in which knee extensor exercises were performed at different range of motion. Methods: Sixteen males performed bouts of 90 maximal isokinetic eccentric contractions over 6 consecutive days (B1-B6) at either small (n=8) or large (n=8) range of motion. Average of peak torque (Mp) of each of the 90 contraction trials were calculated, plasma creatine kinase (CK) and lactate dehydrogenase (LDH) activities were measured before, 24 h, 48 h and 6 d after B1. Muscle soreness was evaluated every day during the experiment. Results: At B3 Mp reduced more in group L than in group S. From B1 to B6 group S increased Mp, while in group L Mp did not return to the baseline level. In both groups CK activity elevated 24 h following B1. CK activity was significantly higher in group L 6d after B1. In group L muscle soreness was higher at 48 h, 72 h, 4 d and 5 d after B1. Conclusion: High-intensity, consecutive eccentric knee extensor exercise training at large range of motion may induce greater development of muscle damage and force deficit, than training at small range of motion. Training at small range of motion may induce early adaptation in voluntary torque production.

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Acta Physiologica Hungarica
Authors:
S. Maghraoui
,
Simona Clichici
,
A. Ayadi
,
C. Login
,
R. Moldovan
,
D. Daicoviciu
,
N. Decea
,
A. Mureşan
, and
L. Tekaya

Asian J. Androl. 2003 5 95 99 Krieg AF, Rosenblum LJ, Henry JB: Lactate dehydrogenase

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(AST), alanine aminotransferase (ALT) and lactate dehydrogenase (LDH). The metabolites and nutritional factors determined were creatinine, total bilirubin (tBIL), blood urea nitrogen (BUN), non-esterified fatty acid (NEFA), beta-hydroxybutyric acid

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