Changes In Lactate Dehydrogenase Activity Research Articles

Trypanosoma evansi triggered neutrophil extracellular traps formation dependent on myeloperoxidase, neutrophil elastase, and extracellular signal-regulated kinase 1/2 signaling pathways

Trypanosoma evansi infects a wide range of hosts to cause huge economic losses in livestock industry. In recent years, it has been demonstrated that neutrophils extracellular traps (NETs) play a critical role in combating parasite infections. However, the role of NETs in the resistance to T. evansi infection is still unclear. In this study, T. evansi induced NETs were observed and their components were determined. The effect of NETs on the viability and motility of T. evansi were estimated. The production of reactive oxygen species (ROS) and Lactate dehydrogenase (LDH) activity in the process of T. evansi-induced NETs formation were detected. The effect of ERK1/2 signaling pathway, neutrophil elastase (NE), myeloperoxidase (MPO), store-operated Ca(2+) entry (SOCE) and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase on T. evansi triggered NETs formation were determined. The results showed that neutrophils could release ETs after being stimulated with T. evansi and the structures of NETs mainly consisted of DNA decorated with histone 3 (H3), NE, and MPO. NETs could reduce the parasite motility without affecting the parasite viability. T. evansi-induced NETs formation was dose and time-dependent and was accompanied by ROS production. Inhibitor assays suggested that the formation of NETs induced by T. evansi was dependent on MPO, NE and ERK1/2 signaling pathway but independent on NADPH oxidase and SOCE. In addition, there was no significant changes in LDH activity during NETs formation. This study is the first report of T. evansi-induced NETs formation.

Early Toxic Effects in a Central American Native Fish (Parachromis dovii) Exposed to Chlorpyrifos and Difenoconazole.

In Costa Rica, agriculture is one of the most important economic activities. Chlorpyrifos and difenoconazole have been identified as agrochemicals widely used in banana and pineapple crops in the Caribbean area of the country and are constantly recorded in aquatic ecosystems. The toxicity of these pesticides in Parachromis dovii was studied. Median lethal concentrations (LC50s) for each substance were obtained from 96-h acute tests. Then, fish were exposed to sublethal concentrations of both substances (10% of LC50), individually and in mixture, to evaluate biomarker responses. Ethoxyresorufin-O-deethylase (EROD), catalase, and glutathione S-transferase activities as well as lipid peroxidation were measured in liver and gill tissues as markers of biotransformation and oxidative stress processes. Cholinesterase activity in brain and muscle tissue was also quantified as a biomarker of toxicity. The LC50s were 55.34 μg/L (95% confidence interval [CI] 51.06-59.98) for chlorpyrifos and 3250 μg/L (95% CI 2770-3810) for difenoconazole. Regarding the biomarkers, a significant inhibition of brain and muscle cholinesterase activity was recorded in fish exposed to 5.50 μg/L of chlorpyrifos. This activity was not affected when fish were exposed to the mixture of chlorpyrifos with difenoconazole. Significant changes in lactate dehydrogenase activity were observed in fish exposed to 325 μg/L of difenoconazole, whereas fish exposed to the mixture showed a significant increase in EROD activity in the liver. These results suggest harmful effects of chlorpyrifos insecticide at environmentally relevant concentrations. There is also evidence for an interaction of the 2 substances that affects the biotransformation metabolism at sublethal levels of exposure. Environ Toxicol Chem 2021;40:1940-1949. © 2021 SETAC.

Cytochemical Evaluation of the Toxic Effects of Combined Antituberculosis Substances on Metabolic State of Blood Lymphocytes.

Combined antituberculosis substances induced a dose-dependent changes in activity of dehydrogenases and hydrolases in rat lymphocytes. The main toxic effect of the substances was related to inhibition of mitochondrial dehydrogenases (succinate dehydrogenase and α-glycerol phosphate dehydrogenase) usually followed by suppression of activity of hydrolytic enzymes (acid phosphatase and non-specific esterase). Opposite changes in lactate dehydrogenase activity reflected specific features of intoxication.

High-intensity interval training with long duration intervals is more effective than short duration intervals for improving glycolytic capacity in the rats' gastrocnemius muscle.

Background There is little data regarding the ability of high-intensity interval training (HIIT) to increase of glycolytic capacity and intramuscular metabolic adaptations. The goal of this study was to evaluate the effects of HIIT (8 weeks, 5 times/week) with short (HIIT1 min: 16 × 1 min work and active recovery at 80-95% and 50-60% VO2max, respectively) and long (HIIT4 min: 4 × 4 min work and active recovery at 80-95% and 50-60% VO2max, respectively) duration intervals and 4 weeks detraining on the levels of phosphofructokinase (PFK), glycogen synthase 1 (GYS1), monocarboxylate transporter 4 (MCT4) and lactate dehydrogenase (LDH) activity in the rats' gastrocnemius muscle. Materials and methods Fifty-four male Wistar rats were assigned into three groups, including HIIT1 min, HIIT4 min and control (Ctrl). After 48 h of the last training session and after 4 weeks of detraining, the rats were sacrificed, and the gastrocnemius muscles were isolated. Results The PFK levels in the HIIT4 min group was significantly higher than in the HIIT1 min and Ctrl groups, and after the detraining period in the HIIT4 minDT group significantly decreased compared to the HIIT4 min group. The LDH activity in the HIIT4 min and HIIT1 min groups were significantly higher than the Ctrl group and the increasing trend in the HIIT4 min group was more than the HIIT1 min group. There was no significant change in LDH activity after detraining compared to training. No significant changes were observed in the level of GYS1 and MCT4 after HIIT. Conclusions Eight weeks of HIIT with long duration intervals induced more improvements in intramuscular glycolytic capacity than a short duration. After short-term detraining, some of these adaptations have remained.

Serum lactate dehydrogenase activity and its isoenzyme patterns in patients with pectus excavatum.

In previous study, we found elevated serum total lactate dehydrogenase (LDH) before correction of pectus excavatum and a decrease in total LDH after the deformity correction. In the present study, we analyzed total LDH activity and its isoenzyme patterns to investigate the causes of these laboratory findings in patients with pectus excavatum. Between March 2014 to December 2018, 85 patients with pectus excavatum who had undergone the Nuss procedure (NP) and bar removal (BR) were included into this study. We analyzed (I) total LDH and its isoenzyme patterns before the correction, (II) relationships of total LDH and its isoenzymes with age at time of NP, sex, severity of pectus excavatum, and pectus morphology types, and (III) post-corrective changes. The mean age of the patients was 13.6 (±6.5) years at the age of NP and the mean interval between NP and BR was 2.2 (±0.42) years. Seventy-one males and 14 females were included. The pectus types included 54 symmetric and 31 asymmetric cases. The mean Haller index before NP and BR were 3.8±1.45 and 2.7±0.4, respectively. The mean of total LDH before NP (pre-correction) and BR (post-correction) were 404.2±80.8 and 369.2±79.3 IU/L, respectively. Before correction, total LDH was significantly higher than normal values, irrespective of age [the young group (<10 years old), P=0.006, and the old group (≥10 years old), P<0.001]. The proportion of LDH5 was significantly higher than that of LDH4 (P<0.001). Total serum LDH was significantly associated with age at time of NP and Haller index (P<0.001 and P=0.030). There was no significant correlation between severity and total LDH. However, the value of only LDH5 among all isoenzymes had a significant positive correlation with severity (P=0.006) and the proportion of only LDH5 in the severe group was significantly higher (P=0.003). After correction, proportions of each isoenzyme were all within the reference range, however, there were significant decreases in values of LDH1-LDH4, except LDH5 (P=0.020, P<0.001, P<0.001, and P=0.029). This study shows that pectus excavatum is a muscular disease entity and that laboratory findings are associated with compression of internal organs, which was explained by post-corrective changes in LDH activity and its isoenzyme patterns. This study will provide a deeper and wider comprehension of pectus excavatum.

Muscle Damage Indicators after Land and Aquatic Plyometric Training Programmes

Plyometric training is an important part of athletic conditioning with many significant benefits, including improved motor abilities and performance, but it can also increase the serum indices of muscle damage, collagen breakdown, muscle swelling, and soreness. Due to the physical characteristics of water, plyometric training in water presents less eccentric contraction, facilitates faster transition from the eccentric to concentric phase of a jump and offers greater resistance during concentric contraction with acute lower indices of muscle damage. To advance our understanding of the long-term effects of an eight-week plyometric training programme on land and in water on muscle damage indicators (lactate dehydrogenase (LDH), creatine kinase (CK) and serum urea (SU)), two experimental groups of physically active men (a group on land (EG1) and a group in water (EG2)) were tested before and after the first and the last plyometric training to monitor muscle damage indicators and adaptations. The results showed changes in CK activity after both plyometric trainings for EG1 and only after the first training for EG2. Moreover, after the eight- week programme, significant difference was observed in CK activity in comparison with EG2. There were no observed changes in LDH activity while SU showed greater changes for the group on land. The plyometric training programme in water resulted in smaller levels of muscle damage indicators. Although both experimental groups conducted the same plyometric training with the same jump volume, the eccentric and concentric loads were not the same, so it can be concluded that adaptations in muscle damage processes are faster with smaller eccentric loads.

Effect of Polycystic Ovary Syndrome and Hormones Disorder on Enzymes Gammaglutamyl Transferase, Oxaloacetic Transaminase, and Proteins

Polycystic ovary syndrome (PCOS) is complex metabolic disorder of endocrine gland in women of reproductive age. The present work illustrate the effect of (PCOS) and hormone disturbance on serum enzymes activities, iron status parameters and hormone profile in patient women suffering from, PCOS, acute kidney disease (AKD) with PCOS, acute kidney disease and iron deficiency anemia (IDA). A total of 160 women, include 135 patients and 25 of control apparently healthy group, patients were subdivided into four groups,(G1) consisted of 50 patients of PCOS, (G2) of 30 patients of PCOS with AKD, (G3) of 30 patient of AKD and (G4) involve 25 patients of IDA. The specimens were collected from different hospital in Baghdad city. The patients and control were investigated for enzymes, gammglutamyltrasferase (GGT), glutamic oxaloacetic transaminase (GOT) or aspartate transaminase (AST) & glutamicpyruvic transaminase (GPT) or alanine transaminase (ALT) lactate dehydrogenase (LDH), total serum proteins (TSP), albumin, globulin, total cholesterol (TC), triglyceride (TG), urea, creatinine and uric acid. Also iron status parameters (serum iron, transferrin saturation percent (TS%), transferrin concentration, and total iron binding capacity (TIBC) and ferritin concentration) were estimated. As well as hormone profile (testosterone (TT), Follicle stimulating hormone (FSH), lutinizing hormone (LH), prolactin (PL), estradiol (E), and progesterone (PRG)) were estimated Results revels highly significant increases for AST or GOT, ALT or GPT, and GGT activities P˂0.001, and a change in LDH of G1 and G2 patients were highly increased P˂0.001 as compared with normal. Remarkable rising was detected in TSP of (G1) patient while there is significant decrease in proteins level of (G2) patients in comparison with normal. Patients of (G3) show significant difference in GGT, LDH and protein. There is significant change in LDH and albumin in (G4), and no change in AST, ALT, GGT, and proteins as compared with normal. Triglyceride (TG), total cholesterol (TC), creatinine show very highly significant change for patients of (G1, G2, G3&G4). Patients women with PCOS show no remarkable change in uric acid and urea and a change in creatinine concentration. Serum iron parameters were changed significantly in patients of (G1, G2, G3, and G4) in comparison with healthy control groups. Hormones levels were significantly different in PCOS patients as compared with normal individual. In conclusion there were remarkable changes in the activities of AST, ALT, GGT, and LDH. This is the first time for the estimation of a change in LDH activity in women with (PCOS) this could be due to genetic and envirmental factor and gene mutation. Hormone levels and iron status parameter changed remarkably may be due to metabolic disturbance and abnormality in the function of hypothalamic neurotransmitter.

Evaluation of the cytolytic effect of tonic with ginseng extract

Experimental evaluation of the cytolytic effect of prolonged use of tonic drink with ginseng extract by determining the activity of enzymes, markers of cytolysis (alanine aminotransferase, aspartate aminotransferase, creatine kinase and lactate dehydrogenase (LDH)) has been carried out. The study was performed on male rats Wistar (n=15, body weight of 461±23 g), to which tonic drink (containing 46 mg/L panaxosides) was administered in the dose 15 mg/kg body weight using a pharyngeal tube. The introduction was carried out three times daily for 21 days. Then the activity of enzymes - markers of cytolysis was determined in blood plasma. Three-factor mathematical models predicting changes in LDH activity under prolonged intake of tonic drink with ginseng extract were constructed by regression analysis. The models were characterized by close ties of effective and factorial signs under reliability level of 95%, were adequate by the Fisher test, and the coefficients were significant by Student's test. It was found that a daily intake three-time intake of tonic drink with ginseng extract for 21 days didn't lead to significant changes in the activity of enzymes, markers of cytolysis. This coincided with the forecast estimate of cytolysis using three-factor mathematical models. However, the proposed mathematical models allowed to reveal that changing in the dosage and concentration of the beverage may increase LDH activity corresponding to cytolysis.

Determination of optimal storage temperature and duration for analysis of total and isoenzyme lactate dehydrogenase activities in canine serum and cerebrospinal fluid.

Lactate dehydrogenase (LDH) exists as 5 isoenzymes in both serum and cerebrospinal fluid (CSF). Human studies have demonstrated that changes in LDH activity can be correlated with a particular disease. Conflicting reports regarding the stability of LDH made it necessary to determine storage conditions before further study of the diagnostic power of this enzyme's activity can be pursued in dogs. The purpose of this study was to optimize measurement of LDH activity and analysis of its isoenzyme profile in canine serum and CSF through proper storage. Serum and CSF were collected from 5 healthy dogs. Samples were stored at 22°C, 4°C, or -20°C for up to 2months. Total LDH activity was measured spectrophotometrically. Isoenzyme profiles were determined using the QuickGel LDH Isoenzyme technique and densitometric scanning. Retention of >70% LDH activity in stored samples was considered clinically acceptable. Serum and CSF stored at -20°C retained >85% of the total LDH activity for 4weeks, although CSF total LDH activity degraded by >10% within 24hours of storage. All serum LDH isoenzymes retained >85% activity for up to 4weeks at -20°C. CSF LDH isoenzyme activity degraded rapidly, therefore CSF LDH should be evaluated within 72hours to assure >75% of LDH isoenzyme activity. Proper storage at -20°C can optimize detection of total LDH activity and the LDH isoenzyme profile in canine serum and CSF. This information is important for evaluating the potential usefulness of LDH in veterinary medicine.

Effect of Selenium Supplementation on Serum Amylase, Lactate Dehydrogenase and Alkaline Phosphatase Activities in Rats Exposed to Cadmium or Lead

Abstract The purpose of the study was to assess the effect of selenium supplementation on serum amylase, lactate dehydrogenase (LDH) and alkaline phosphatase (ALP) activities in rats, during subacute exposure to toxic doses of cadmium or lead through the drinking water. The experimental groups (n=6) were: Control, Se (Se+4: 0,2 mg/l), Cd (Cd+2: 150 mg/l), Pb (Pb+2: 300 mg/l), Cd+Se (Cd+2: 150 mg/l; Se+4: 0,2 mg/l) and Pb+Se (Pb+2: 300 mg/l; Se+4: 0,2 mg/l). The animals were sacrificed after 56 days. Amylase, LDH and ALP activities were determined from serum. Se and Pb treatments caused an increase in amylase and LDH activities, when compared to Control group while Cd caused an increase in amylase activity and a decrease in LDH and ALP activities. Cd+Se caused a decrease in amylase activity and an increase in LDH activity, when compared to Cd. Pb+Se caused a decrease in amylase activity in comparison to lead. Selenium supplementation alleviated cadmium or lead induced changes in serum amylase activity. Selenium, coadministered with cadmium, caused a marked increase in serum LDH activity, when compared to cadmium alone or Control group while practically it had no effect on lead induced changes in LDH activity. Cadmium and lead induced disturbances in serum ALP activity were not influenced by selenium supplementation.

Differential effects of short-term β agonist and growth hormone treatments on expression of myosin heavy chain IIB and associated metabolic genes in sheep muscle

Growth hormone (GH) and β agonists increase muscle mass, but the mechanisms for this response are unclear and the magnitude of response is thought to vary with age of animal. To investigate the mechanisms driving the muscle response to these agents, we examined the effects of short-term (6 day) administration of GH or cimaterol (a β2-adrenergic agonist, BA) on skeletal muscle phenotype in both young (day 60) and mature (day 120) lambs. Expression of myosin heavy chain (MyHC) isoforms were measured in Longissimus dorsi (LD), Semitendinosus (ST) and Supraspinatus (SS) muscles as markers of fibre type and metabolic enzyme activities were measured in LD. To investigate potential mechanisms regulating the changes in fibre type/metabolism, expression or activity of a number of signalling molecules were examined in LD. There were no effects of GH administration on MyHC isoform expression at either the mRNA or protein level in any of the muscles. However, BA treatment induced a proportional change in MyHC mRNA expression at both ages, with the %MyHCI and/or IIA mRNA being significantly decreased in all three muscles and %MyHCIIX/IIB mRNA significantly increased in the LD and ST. BA treatment induced de novo expression of MyHCIIB mRNA in LD, the fastest isoform not normally expressed in sheep LD, as well as increasing expression in the other two muscles. In the LD, the increased expression of the fastest MyHC isoforms (IIX and IIB) was associated with a decrease in isocitrate dehydrogenase activity, but no change in lactate dehydrogenase activity, indicating a reduced capacity for oxidative metabolism. In both young and mature lambs, changes in expression of metabolic regulatory factors were observed that might induce these changes in muscle metabolism/fibre type. In particular, BA treatment decreased PPAR-γ coactivator-1β mRNA and increased receptor-interacting protein 140 mRNA. The results suggest that the two agents work via different mechanisms or over different timescales, with only BA inducing changes in muscle mass and transitions to a faster, less oxidative fibre type after a 6-day treatment.

Investigation of irradiation by different nonablative lasers on primary cultured skin fibroblasts

A variety of lasers with different wavelengths and biological effects are widely used for nonablative skin rejuvenation, but the underlying mechanisms have not been fully investigated. To investigate the effects of irradiation by different nonablative lasers on collagen synthesis and the antioxidant status of cultured fibroblasts to identify a possible mechanism for laser photorejuvenation. Cultured skin fibroblasts were irradiated with three different lasers: 532 nm potassium-titanyl phosphate (KTP), 1064 nm Q-switched neodymium:yttrium-aluminium-garnet (Nd:Yag) and 1064 nm long-pulse Nd:YAG, and production of collagen and changes in lactate dehydrogenase (LDH), malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) were assayed. Irradiation by all three lasers led to a marked increase in collagen production. Two major antioxidant enzymes, SOD and GSH, were significantly increased, whereas MDA was markedly reduced after laser irradiation. No change in LDH activity was found between nonirradiated and irradiated fibroblasts. This study indicates that the increased collagen synthesis by fibroblasts after laser treatment may be partly due to improved antioxidant capacity, which reduces oxidative stress and thus stimulates new collagen production.

Biomarkers as a tool to assess effects of chromium (VI): Comparison of responses in zebrafish early life stages and adults

The present work aims to compare the sensitivity of embryos and adult zebrafish to chromium (VI) (as potassium dichromate) focusing on biomarkers (cholinesterase, glutathione S-transferase and lactate dehydrogenase) as endpoints. Zebrafish eggs showed less sensitivity to Cr (VI) (96 h-LC 50 = 145.7 mg/L) than adults (96 h-LC 50 = 39.4 mg/L) probably due to the protective action of the chorion. However, biomarkers were much more responsive in larvae than in adults and gave clear indications about Cr (VI) mode of action: it seems to be neurotoxic (inhibited cholinesterase), to inhibit glutathione S-transferase activity and to interfere with cellular metabolic activity (changes in lactate dehydrogenase activity) in larvae. In adults, only glutathione S-transferase was responsive, showing a clear inhibition. The responsiveness of the analyzed biomarkers in larvae reinforces the idea of the usefulness of early life stage assays in the assessment of chemicals effects. Moreover, early life stage assays also contributed with relevant information regarding anomalies in larvae development and behavior. Further research should focus on the use of biomarkers to assess long term effects which are ecologically more relevant.

Effects and mechanism of glucagon-like peptide-1 on injury of rats cardiomyocytes induced by hypoxia-reoxygenation

Although the insulinotropic role of glucagon-like peptide-1 (GLP-1) in type 2 diabetes mellitus has been substantiated, its role in cardioprotection remains largely unknown. This study aimed to determine the effects of GLP-1 on injury of rats cardiac myocytes induced by hypoxia-reoxygenation (H/R) and the possible mechanisms. The cultured neonatal rats cardiac myocytes were randomly divided into seven groups: the normal control group, the H/R group, the GLP-1 + H/R group, the GLP-1 + H/R + UO126 (the p42/44 mitogen-activated protein kinase (MAPK) inhibitor) group, the GLP-1 + H/R + LY294002 (phosphatidylinositol 3-kinase (PI3K) inhibitor) group, the H/R + UO126 group, and the H/R + LY294002 group. The lactate dehydrogenase (LDH) activity, apoptosis rate of cardiac myocytes, and caspase-3 activity were detected after the injury of H/R. Compared with the normal control group, the activity of LDH, cardiac myocyte apoptosis rate, and caspase-3 activity all increased significantly in the H/R group (P < 0.01). Compared with the H/R group, these three indices all decreased in the H/R + GLP-1 group (P < 0.01). However, the changes of LDH activity, apoptosis rate, and caspase-3 activity were inhibited by LY294002 and UO126 respectively. GLP-1 can directly act on cardiac myocytes and protect them from H/R injury mainly by inhibiting their apoptosis. Its mechanism may be through the PI3K-Akt pathway and the MAPK signaling pathway.

Cambios en el ECG y la actividad enzimática en corazón de rata tras infarto de miocardio: efecto de la TPP y del MnCl2

Heart infarction is one of the main causes of death in the human population. Assurance of a sufficient level of bioenergetic processes is very important for the heart after infarction. Mn2+ as well as thiamine pyrophosphate (TPP) are positive effectors of the pyruvate dehydrogenase complex (PDH) and the 2-oxoglutarate dehydrogenase complex (OGDH), both of which play a very important role in the Krebs cycle. Thus, we have established the effect of MnCl2 (10mg/kg) and TPP (20mg/kg)--4 injections every 12 h--on the activity of PDH, OGDH, lactate dehydrogenase (LDH) and malate dehydrogenase (MDH). Additionally, we perform an analysis of ECG to affirm the changes in the heart electrophysiology of healthy rats after MnCl2 and TPP treatment. We then analyzed changes in the activity of these enzymes after experimental myocardial infarction in rats. We observed a decrease of OGDH and MDH activity in rat hearts after infarction in comparison with sham-operated rats. Treatment of healthy rats with MnCl2 caused an increase of OGDH activity. Moreover both MnCl2 and TPP caused an increase of PDH activity and a decrease of MDH activity (TPP revealed a stronger effect). We found no changes in LDH activity. Electrocardiography data showed a slight shortening of the QT interval and an enhanced heartbeat rate after treatment with MnCl2. TPP caused only elongation of the QT interval. In conclusion, application of MnCl2 enhanced the activity of some very important enzymes in the respiration process (PDH and OGDH). This effect, connected with enhanced heartbeat and a slightly shortened ventricle relaxation, may have potential application during the key period of convalescence following heart infarction.

Transition from ectothermy to endothermy: the development of metabolic capacity in a bird (Gallus gallus).

The evolution of endothermy is one of the most significant events in vertebrate evolution. Adult mammals and birds are delineated from their early ontogenetic stages, as well as from other vertebrates, by high resting metabolic rates and consequent internal heat production. We used the embryonic development of a bird (Gallus gallus) as a model to investigate the metabolic transition between ectothermy and endothermy. Increases in aerobic capacity occur at two functional levels that are regulated independently from each other: (i) upregulation of gene expression; and (ii) significant increases in the catalytic activity of the main oxidative control enzymes. Anaerobic capacity, measured as lactate dehydrogenase activity, is extremely high during early development, but diminishes at the same time as aerobic capacity increases. Changes in lactate dehydrogenase activity are independent from its gene expression. The regulatory mechanisms that lead to endothermic metabolic capacity are similar to those of ectotherms in their response to environmental change. We suggest that the phylogenetic occurrence of endothermy is restricted by its limited selective advantages rather than by evolutionary innovation.

Lung cytotoxicity of combined exposure to refractory ceramic fibres and cigarette smoke.

Changes in some lung cytotoxic parameters after exposure to refractory ceramic fibres (RCF) or to cigarette smoke (S) and after combined exposure to RCF+S were studied in male Wistar rats in order to evaluate their potential adverse health effects. Four groups of rats were treated as follows : 1) intratracheally instilled by saline solution (0.4 ml); 2) intratracheally instilled by 4 mg of RCF; 3) exposed only to S (85 mg of total particulate matter/m(3) air ) for two hours daily; 4) exposed to RCF+S. After 6 months the animals were exsanguinated and the bronchoalveolar lavage (BAL) was perfomed. Viability and phagocytic activity of alveolar macrophages (AM), activity of lactate dehydrogenase (LDH) in cell-free BAL fluid (cf-BALF), acid phosphatase (ACP) and cathepsin D (CATD) in cfBALF, in BALF cells and in the lung tissue were estimated. Viability of AM was depressed by every type of exposure with RCF+S effect being at least additive. Phagocytic activity of AM increased in the presence of RCF. No significant changes in LDH activity were found. Activities of lysosomal enzymes measured in the lung tissue homogenates were not significantly changed, but those in the cfBALF increased especially after exposure to S with most expressive increase in BALF cells after exposure to S and RCF+S. In the case of CATD the effect of RCF+S was more than additive. The results point out to the persistence of the RCF exposure cytotoxic effects and their amplification by cigarette smoke.

Comparisons of physiological and biochemical responses between milkfish ( Chanos chanos) and grass carp ( Ctenopharyngodon idella) to cold shock

Temporal changes in physiological parameters and enzyme activities related to carbohydrate metabolism in the milkfish ( Chanos chanos) and the grass carp ( Ctenopharyngodon idella) under cold shock at 15 °C were examined in order to better understand thermal compensation mechanisms of teleosts with different cold tolerances. The plasma glucose, lactate, and lipid contents as well as enzyme activities of citrate synthase, glucose-6-phosphate dehydrogenase, fructose-1,6-bisphosphatase, phosphorylase a, and lactate dehydrogenase at varying time intervals were monitored. The results show that changes in plasma glucose and lipid contents of the milkfish were more notable than those of the grass carp, but the elevation in plasma lactate contents in the grass carp occurred earlier and was much greater than that in the milkfish. Furthermore, changes in plasma glucose contents in the milkfish were correlated with the enzyme activities of phosphorylase a and fructose-1,6-bisphosphatase, but in the grass carp they were correlated with glucose-6-phosphate dehydrogenase and lactate dehydrogenase activities instead. In addition, the change in lactate dehydrogenase activity in the grass carp was more notable than those of other enzymes, but lactate dehydrogenase activities in the milkfish steadily decreased during cold compensation. The results demonstrate that the two species (milkfish and grass carp) respond quite differently to cold shock, and this may be related to their differences in cold tolerance.

The effect of desflurane on ameliorating cerebral infarction in rats subjected to focal cerebral ischemia-reperfusion injury

To obtain more information on the cerebral ischemia and reperfusion injury under desflurane anesthesia, we compared the infarct volume and lactate dehydrogenase (LDH) activity in rats subjected to focal cerebral ischemia during different concentration of desflurane anesthesia. Male Long-Evans rats weighing 270–350 g were anesthetized with desflurane in air at 1.0, 1.25 or 1.5 MAC whereas rats in the control group received intraperitoneal chloral hydrate (400 mg/kg) anesthesia. Cerebral infarction was induced by microsurgical procedures with ligation of the right middle cerebral artery (MCA) and clipping of the bilateral common carotid arteries (CCA) for 60 minutes. The rats were sacrificed 24 hours later, serial brain slices of 2mm thickness were taken and stained for the measurement of the infarct area. Cellular damage was evaluated by measuring the LDH level in the plasma. Desflurane (1.0, 1.25 or 1.5 MAC by inhalation) and chloral hydrate (400 mg/kg; ip.) did not produce any changes in pH, blood gases, heart rate or mean arterial blood pressure. In the rats subjected to focal cerebral ischemia, the volume of infarction was significantly less in the desflurane groups in all three different concentrations than in the chloral hydrate group. The changes of LDH activity in plasma also correlated with the result of the infarct volume. Our study suggests that desflurane may offer a neuroprotective effect such as decreased infarct volume after focal cerebral ischemia.

Seasonal variation in biochemical indicators of physiological status in Euphausia superba from Port Foster, Deception Island, Antarctica

Seasonal changes in biochemical indicators of physiological status were analyzed in abdominal muscle of the Antarctic krill, Euphausia superba, collectedfrom Port Foster, Deception Island , an active volcano locatedin the ShetlandIslandchain west of the Antarctic Peninsula. Krill were collectedwith a 10 m 2 MOCNESS trawl during four cruises (November 1999, February, May, November 2000). RNA:DNA mirroredthe chlorophyll a concentration, with the highest values found during seasons of abundant phytoplankton. Activities of the glycolytic enzyme lactate dehydrogenase (LDH) and the mitochondrial enzyme citrate synthase (CS) were significantly higher in male krill when comparedto females of similar size, indicating that their burst andaerobic swimming performance may be higher than females throughout the year. RNA:DNA ratio andenzyme activities were highly elevatedin summer as comparedto the earliest spring sampling period. Krill showed significant seasonal changes in LDH activity, with lowest values in spring andhighest values in summer (females) or autumn (males). Krill showedsignificant seasonal changes in CS activity with highest values in summer. Protein and% water variedsignificantly among seasons for both males and females. Lower CS activity and RNA:DNA ratio suggest krill exhibit reduced metabolism during the winter when phytoplankton production is reduced, perhaps enhancing survival. Lower enzyme activities in female krill in early spring suggest they may achieve greater metabolic suppression during overwintering. r 2003 Elsevier Ltd. All rights reserved.