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Background: Differential diagnosis can be a challenge for eosinophilic subtypes of renal cell tumors due to their overlapping histomorphological and immunohistochemical features. We aimed to investigate the frequency of rare variants of renal cell carcinomas (RCCs) such as succinate dehydrogenase-deficient RCC (SDDRCC), hereditary leiomyomatosis and RCC (HLRCC)-associated RCC, and eosinophilic, solid, and cystic RCC (ESCRCC) in our population., Materials and Methods: Renal tumors which could be considered in the eosinophilic tumor category were included: 91 conventional clear cell RCCs with eosinophilic cytoplasm, 72 papillary RCCs, 74 chromophobe RCCs, 88 oncocytomas, and 37 other rare subtypes. Using the tissue microarray method, succinate dehydrogenase B (SDHB), fumarate hydratase (FH), and cytokeratin 20 (CK20) antibodies were performed by immunohistochemistry. Immunohistochemistry was repeated on whole block sections for selected cases. The utility of these antibodies in the differential diagnosis was also investigated., Results: Loss of SDHB expression was detected in three tumors, two of which showed typical morphology for SDDRCC. In additional two tumors, SDHB showed weak cytoplasmic expression without a mitochondrial pattern (possible-SDHB deficient). None of the tumors showed loss of FH expression. Heterogeneous reactions were observed with SDHB and FH antibodies. Only one ESCRCC was detected with diffuse CK20 positivity., Conclusion: SDDRCCs, HLRCC-associated RCCs, and ESCRCCs are very rare tumors depending on the population. Possible weak staining and focal loss of SDHB and FH expression should be kept in mind and genetic testing must be included for equivocal results., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Background: Glioblastoma is the most common primary malignant tumor of the central nervous system that occurs in the spinal cord or brain. Pseudosynanceia melanostigma is a venomous stonefish in the Persian Gulf, which our knowledge about is little. This study’s goal is to investigate the toxicity of stonefish crude venom on mitochondria isolated from U87 cells. Methods: In the first stage, we extracted venom stonefish and then isolated mitochondria have exposed to different concentrations of venom. Finally, mitochondrial toxicity parameters (Succinate dehydrogenase (SDH) activity, Reactive oxygen species (ROS), cytochrome c release, Mitochondrial Membrane Potential (MMP), and mitochondrial swelling) have evaluated. Results: To determine mitochondrial parameters, we used 115, 230, and 460 µg/ml concentrations. The results of our study show that the venom of stonefish selectively increases upstream parameters of apoptosis such as mitochondrial swelling, cytochrome c release, MMP collapse and ROS. Conclusion: This study suggests that Pseudosynanceia melanostigma crude venom has selectively caused toxicity by increasing active mitochondrial oxygen radicals. This venom could potentially be a candidate for the treatment of glioblastoma.

The acaricides cyflumetofen, cyenopyrafen, and pyflubumide act as inhibitors of the mitochondrial electron transport system at complex II (succinate dehydrogenase; SDH), a new mode of action in arthropods. The development and mechanisms of low-level resistance against cyenopyrafen and cyflumetofen have been previously reported in Tetranychus urticae. In the present study, we investigated high levels of resistance against three SDH inhibitors in T. urticae field populations and clarify the genetic basis of resistance using quantitative trait locus (QTL) analysis. First, we constructed a microsatellite linkage map comprising 64 markers assembled into three linkage groups (LGs) with total length of 683.8 cM and average marker spacing of 11.03 cM. We then used the linkage map to perform QTL mapping, and identified significant QTLs contributing to resistance to cyflumetofen (one QTL on LG1), cyenopyrafen (one QTL on LG3), and pyflubumide (two QTLs on LG1 and LG3). The QTL peaks on LG1 for cyflumetofen and pyflubumide overlapped and included the SdhB locus. For cyenopyrafen resistance, the QTLs on LG3 included the SdhC locus. For cyflumetofen resistance, we found an I260T mutation in SdhB. For pyflubumide and cyenopyrafen resistance, we detected I260V and S56L substitutions in SdhB and SdhC, respectively, by direct sequencing. Both I260 in SdhB and S56 in SdhC were present in highly conserved regions of the ubiquinone binding site formed at the interface among SdhB, SdhC, and SdhD. Mutations at these positions have been implicated in resistance against fungicides that act as Sdh inhibitors in various pathogens. Therefore, we consider these mutations to be target-site resistance mutations for these acaricidal SDH inhibitors., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Flavonoids are natural compounds that show various biological effects, such as the anti-cancer effect. Chrysin is a flavonoid compound found in honey and propolis. Studies have shown that chrysin has anti-cancer activity due to induction of apoptosis signaling. In the present study, we examined the cytotoxic effect of chrysin against liver mitochondria obtained from the hepatocellular carcinoma (HCC) rat model. Diethylnitrosamine (DEN) and 2-acetylaminofluorene (2-AAF) was used for induction of HCC. Mitochondria were isolated from liver hepatocytes using differential centrifugation. Then, hepatocytes and mitochondria markers related to apoptosis signaling were investigated. Our finding indicated an increase in mitochondrial reactive oxygen species (ROS) generation, collapse in the mitochondrial membrane potential (MMP), swelling in mitochondria, and cytochrome c release (about 1.6 fold) after exposure of mitochondria obtained from the HCC rats group with chrysin (10, 20, and 40 µM) compared to the normal rats group. Furthermore, Chrysin was able to increase caspase-3 activity in the HCC rats group (about 2.4 fold) compared to the normal rats group. According to the results, we proposed that chrysin could be considered as a promising complementary therapeutic candidate for the treatment of HCC, but it requires a further in vivo and clinical studies., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Background: The widespread occurrence of fungicide resistance in fungal plant pathogens requires the development of new compounds with different mode(s) of action (MOA) to avoid cross resistance. This will require a rapid method to identify MOAs., Results: Here, gas chromatography-mass spectrometry (GC-MS) based metabolic fingerprinting was used to elucidate the MOAs of fungicides. Botrytis cinerea, an important pathogen of vegetables and flowers, can be inhibited by a wide range of chemical fungicides with different MOAs. A sensitive strain of B. cinerea was exposed to EC 50 concentrations of 13 fungicides with different known MOAs and one with unknown MOA. The mycelial extracts were analyzed for their "metabolic fingerprint" using GC-MS. A comparison among the GC-MS vector' profiles of cultures treated with fungicides were performeded. A model based on hierarchical clustering was established which allowed these antifungal compounds to be distinguished and classified coinciding with their MOAs. Thus, metabolic fingerprinting represents a rapid, convenient, and information-rich method for classifying the MOAs of antifungal substances. The biomarkers of fungicide MOAs were also established by an analysis of variance and included succinate for succinate dehydrogenase inhibitors and cystathionine for methionine synthesis inhibitors. Using the metabolic model and the common perturbation of metabolites, the new fungicide SYP-14288 was identified as having the same MOA as fluazinam., Conclusion: This study provides a comprehensive database of the metabolic perturbations of B. cinerea induced by diverse MOA inhibitors and highlights the utility of metabolic fingerprinting for defining MOAs, which will assist in the development and optimization of new fungicides.

Brain damage is a leading cause of death in patients with cardiac arrest (CA). The accumulation of succinate during ischemia by succinate dehydrogenase (SDH) is an important mechanism of ischemia-reperfusion injury. It was unclear whether inhibiting the oxidation of accumulated succinate could also mitigate brain damage after CA. In this study, rats were subjected to a 6 min of CA, and cardiopulmonary resuscitation (CPR) was performed with administration of normal saline or dimethyl malonate (DMM, a competitive inhibitor of SDH). After the return of spontaneous circulation, neurological function of the rats was assessed by a tape removal test for 3 days. The rats were then sacrificed, and their brains were used to assess neuronal apoptosis by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay. Hippocampal tissues were used for Western blotting analysis and biochemical detection. In addition, hippocampal mitochondria during CA and CPR were isolated. The relative mitochondrial membrane potential (MMP) and cytochrome C in the cytosol were detected. Our results show that DMM promoted ROSC and neurological performance in rats after CA. The TUNEL assay showed that DMM reduced neuronal apoptosis. Western blotting analysis showed that DMM inhibited the activation of caspase-3 and enhanced the expression of HIF-1α. Moreover, DMM inhibited excessive hyperpolarization of MMP after CPR, and prevented the release of cytochrome C. Therefore, inhibiting SDH by DMM alleviated brain damage after CA, and the main mechanisms included inhibiting the excessive hyperpolarization of MMP, reducing the generation of mtROS and stabilizing the structure of HIF-1α., (Copyright © 2018 IBRO. Published by Elsevier Ltd. All rights reserved.)

Objective: Investigate the effect of three-dimensional conformal radiotherapy (3DCRT) on locally recurrent nasopharyngeal carcinoma (NPC) on the expression of succinate dehydrogenase B (SDHB)., Patients and Methods: Eighty-six patients diagnosed with locally recurrent NPC in our hospital were selected and divided into the control group (43 cases) and observation group (43 cases). Conventional two-dimensional radiotherapy was applied in the control group, and 3DCRT was adopted in the observation group. The curative effect of both groups was compared., Results: The effective rate and the degree of alleviation of the observation group were higher than those of the control group, and the differences were statistically significant (p<0.05). There were no differences in the occurrence rate of complications from radiotherapy between the two groups (p>0.05). The survival rate and median survival time of the observation group were significantly higher than those of the control group (p<0.05). The positive expression rate of SDHB in the observation group after radiotherapy was significantly higher than that of the control group (p<0.05), and the median survival time of patients with positive expression of SDHB was significantly higher than patients with negative expression (p<0.05)., Conclusions: 3DCRT applied for treatment of locally recurrent NPC was safe and effective. It also improved the positive expression rate of SDHB, which was associated with increased survival time.

Objectives: To investigate the mechanisms of the anti-hyperglycemic effect of Costus speciosus (C. speciosus) root ethanolic extracts (CSREt) by assessing its action on insulin synthesis and glucose catabolic enzyme gene expression and activities in streptozotocin (STZ) diabetic rats., Methods: This study was carried out at the Biochemical Laboratory, Faculty of Veterinary Medicine, Zagazig University, Zagazig, Egypt between July and August 2013. Sixty male albino rats (120 +/- 20 g weight, and 6 months old) were used and divided into 6 groups (n=10). Two groups served as diabetic and nondiabetic controls. Four groups of STZ diabetic animals were given oral C. speciosus (CSREt) in doses of 200, 400, and 600 mg/kg body weight, and 600 µg/kg body weight of the standard drug glibenclamide for 4 weeks., Results: The CSREt 400 and 600 mg/kg body weight induced a decrease in blood glucose and an increase in serum insulin level, glucokinase (GK), aldolase, pyruvate kinase (PK), succinate dehydrogenase (SDH), and glycogen synthase activities  in addition to a higher expression level of insulin, insulin receptor A (IRA), GK, PK, SDH, and glucose transporting protein., Conclusion: The C. speciosus has anti-hyperglycemic activity. It induces insulin secretion and release from cells, as well as stimulates the tissue's insulin sensitivity leading to an increase of the tissues' glucose uptake, storage, and oxidation.

The present study was aimed to investigate the potential beneficial effect of curcumin, a polyphenol with pleiotropic properties, on mitochondrial dysfunctions, oxidative stress and cognitive deficits in a kindled model of epilepsy. Kindled epilepsy was induced in rats by administering a sub-convulsive dose of pentylenetetrazole (PTZ, 40 mg/kg body weight) every alternate day for 30 days. PTZ administered rats exhibited marked cognitive deficits assessed using active and passive avoidance tasks. This was accompanied by a significant decrease in NADH:cytochrome-c reductase (complex I) and cytochrome-c oxidase (complex IV) activities along with an increase in ROS, lipid peroxidation and protein carbonyls. The levels of glutathione also decreased in the cortex and hippocampus. Electron micrographs revealed disruption of mitochondrial membrane integrity with distorted cristae in PTZ treated animals. Histopathological examination showed pyknotic nuclei and cell loss in the hippocampus as well as in the cortex of PTZ treated animals. Curcumin administration at a dose of 100 mg/kg, p.o. throughout the treatment paradigm was able to ameliorate cognitive deficits with no significant effect on seizure score. Curcumin was able to restore the activity of mitochondrial complexes. In addition, significant reduction in ROS generation, lipid peroxidation and protein carbonyls was observed in PTZ animals supplemented with curcumin. Moreover, glutathione levels were also restored in PTZ treated rats supplemented with curcumin. Curcumin protected mitochondria from seizure induced structural alterations. Further, the curcumin supplemented PTZ rats had normal cell morphology and reduced cell loss. These results suggest that curcumin supplementation has potential to prevent mitochondrial dysfunctions and oxidative stress with improved cognitive functions in a chronic model of epilepsy., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Aim: Caffeine is one of the most widely consumed behaviorally active substances in the world. Although its effects on the central nervous system and bone metabolism have been documented, as yet there is no report on its effect on tissues in the oral cavity. In this study we analyzed the viability of human gingival fibroblasts (HGF) and alkaline phosphatase (ALP) enzyme activity after exposure to different concentrations of caffeine for different exposure time periods., Methods: The HGF were cultured with different concentrations of caffeine. Viability of cells exposed to caffeine was analyzed by the 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide (MTT) assay to assess mitochondrial dehydrogenase activity. The activity of ALP was analyzed at specific time intervals after caffeine addition., Results: Our results showed that caffeine of concentrations <1 mm did not affect the viability of HGF and the ALP enzyme activity. Nevertheless, caffeine at 5 and 10 mm dramatically decreased the viability and ALP activity of the cells after 4 days such that, by day 9, the viability of cells declined to near zero in the 10 mm group., Conclusion: These results provided evidence that caffeine in high concentrations can decrease cellular viability and ALP activity in HGF., (© 2012 Wiley Publishing Asia Pty Ltd.)

Background: The adenosine triphosphate-sensitive potassium (KATP) channel opener, diazoxide, preserves myocyte volume homeostasis and contractility during stress via an unknown mechanism. Pharmacologic overlap has been suggested between succinate dehydrogenase (SDH) activity and KATP channel modulators. Diazoxide may be cardioprotective due to the inhibition of SDH which may form a portion of the mitochondrial KATP channel. To determine the role of inhibition of SDH in diazoxide's cardioprotection, this study utilized glutathione to prevent the inhibition of SDH., Methods: SDH activity was measured in isolated mitochondria exposed to succinate (control), malonate (inhibitor of succinate dehydrogenase), diazoxide, and varying concentrations of glutathione alone or in combination with diazoxide. Enzyme activity was measured by spectrophotometric analysis. To evaluate myocyte volume and contractility, cardiac myocytes were superfused with Tyrode's physiologic solution (Tyrode's) (20 minutes), followed by test solution (20 minutes), including Tyrode's, hyperkalemic cardioplegia (stress), cardioplegia + diazoxide, cardioplegia + diazoxide + glutathione, or glutathione alone; followed by Tyrode's (20 minutes). Myocyte volume and contractility were recorded using image grabbing software., Results: Both malonate and diazoxide inhibited succinate dehydrogenase. Glutathione prevented the inhibition of succinate dehydrogenase by diazoxide in a dose-dependent manner. The addition of diazoxide prevented the detrimental myocyte swelling due to cardioplegia alone and this benefit was lost with the addition of glutathione. However, glutathione elicited an independent cardioprotective effect on myocyte contractility., Conclusions: The ability of diazoxide to provide beneficial myocyte homeostasis during stress involves the inhibition of succinate dehydrogenase, which may also involve the opening of a purported mitochondrial adenosine triphosphate sensitive potassium channel., (Copyright © 2013 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

The aim of this study was to evaluate the possibility of fluoride solutions applied to enamel to protect pulp cells against the trans-enamel and transdentinal cytotoxicity of a 16% carbamide peroxide (CP) bleaching gel. The CP gel was applied to enamel/dentin discs adapted to aicial pulp chambers (8 h/day) during 1, 7 or 14 days, followed by fluoride (0.05% or 0.2%) application for 1 min. The extracts (culture medium in contact with dentin) were applied to MDPC-23 cells for 1 h, and cell metabolism (MTT assay), alkaline phosphatase (ALP) activity and cell membrane damage (flow cytometry) were analyzed. Knoop microhardness of enamel was also evaluated. Data were analyzed statistically by ANOVA and Kruskal-Wallis tests (α=0.05). For the MTT assay and ALP activity, significant reductions between the control and the bleached groups were observed (p<0.05). No statistically significant difference occurred among bleached groups (p>0.05), regardless of fluoride application or treatment days. Flow cytometry analysis demonstrated 30% of cell membrane damage in all bleached groups. After 14 days of treatment, the fluoride-treated enamel presented significantly higher microhardness values than the bleached-only group (p<0.05). It was concluded that, regardless of the increase in enamel hardness due to the application of fluoride solutions, the treated enamel surface did not prevent the toxic effects caused by the 16% CP gel to odontoblast-like cells.

The effect of common salt (NaCl) on ion contents, Krebs cycle intermediates and its regulatory enzymes was investigated in growing mungbean (Vigna radiata L. Wilczek, B 105) seedlings. Sodium and chloride ion contents increased in both root and shoot whereas potassium ion content decreased in shoot of test seedlings with increasing concentrations of NaCl. Organic acids like pyruvate and citrate levels increased whereas malate level decreased under stress in both roots and shoots. Salt stress also variedly affected the activities of different enzymes of respiratory chain. The activity of pyruvate dehydrogenase (E.C. 1.2.4.1) decreased in 50 mM NaCl but increased in 100 mM and 150 mM concentrations, in both root and shoot samples. Succinate dehydrogenase (E.C. 1.3.5.1) activity was reduced in root whereas stimulated in shoot under increasing concentrations of salt. The activity of isocitrate dehydrogenase (E.C. 1.1.1.41) and malate dehydrogenase (E.C. 1.1.1.37) decreased in both root and shoot samples under salt stress. On the contrary, pretreatment of mungbean seeds with sublethal dose of NaCl was able to overcome the adverse effects of stress imposed by NaCl to variable extents with significant alterations of all the tested parameters, resulting in better growth and efficient respiration in mungbean seedlings. Thus, plants can acclimate to lethal level of salinity by pretreatment of seeds with sublethal level of NaCl, which serves to improve their health and production under saline condition, but the sublethal concentration of NaCl should be carefully chosen., (Copyright © 2012 Elsevier Masson SAS. All rights reserved.)

We undertook a longitudinal study of the histological and biochemical changes at the neuromuscular junction (NMJ) in muscles of SOD1-G93A mice. We also assessed these functions in mice treated with a known heat shock protein inducer, arimoclomol. Tissue samples of treated and untreated mSOD mice were analysed for AChE and ChAT enzyme activities as markers of neuromuscular function. Sections of hindlimb muscles (TA, EDL and soleus) were also stained for succinate dehydrogenase and silver cholinesterase activities as well as for immunohistochemistry. Hsp70 levels were also measured from muscle samples using ELISA. Results showed that denervation and nerve sprouting were present at symptom onset in fast muscles, although slow muscles remained fully innervated. Cholinergic enzyme activities were reduced prior to denervation and declined further with disease progression. Reduction of endplate size, a slow to fast shift in muscle phenotype was also observed. Treatment with arimoclomol delayed the appearance of these changes, increased innervation, cholinergic enzyme activities and endplate size and reversed muscle fibre transformation. These beneficial effects of arimoclomol in muscles were accompanied by an increase in Hsp70 expression. In conclusion, our results indicate that pharmacological targeting of muscles at early stages of disease may be a successful strategy to ameliorate disease progression in ALS.

Arsenicosis, due to contaminated drinking water, is a serious health hazard in terms of morbidity and mortality. Arsenic induced free radicals generated are known to cause cellular apoptosis through mitochondrial driven pathway. In the present study, we investigated the effect of arsenic interactions with various complexes of the electron transport chain and attempted to evaluate if there was any complex preference of arsenic that could trigger apoptosis. We also evaluated if chelation with monoisoamyl dimercaptosuccinic acid (MiADMSA) could reverse these detrimental effects. Our results indicate that arsenic exposure induced free radical generation in rat neuronal cells, which diminished mitochondrial potential and enzyme activities of all the complexes of the electron transport chain. Moreover, these complexes showed differential responses towards arsenic. These early events along with diminished ATP levels could be co-related with the later events of cytosolic migration of cytochrome c, altered bax/bcl(2) ratio, and increased caspase 3 activity. Although MiADMSA could reverse most of these arsenic-induced altered variables to various extents, DNA damage remained unaffected. Our study for the first time demonstrates the differential effect of arsenic on the complexes leading to deficits in bioenergetics leading to apoptosis in rat brain. However, more in depth studies are warranted for better understanding of arsenic interactions with the mitochondria., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Nitric Oxide (NO) plays an important role in iron redistribution during exercise, while its molecular regulatory mechanism is still not clear. Our present studies were to investigate the effects of NO on iron metabolism and to elucidate the regulatory mechanism of iron transport in skeletal muscle both in vivo and in vitro. One group of male Wistar rats (300 +/- 10 g) were subjected to an exercise of 30 min on a treadmill for 5 weeks (exercise group, EG, 6 rats) and the other one was placed on the treadmill without running (control group, CG, 6 rats). The cultured L6 rat skeletal muscle cells were treated with either 0.5 mM SNAP (NO donor) or not for 24 h, and their iron release and intake amount were examined by measuring radiolabelled (55)Fe. The results showed: (1) The NO content (CG, 1.09 +/- 0.18 micromol/g vs. EG, 1.49 +/- 0.17 micromol/g) and non-heme iron in gastrocnemius (CG, 118.35 +/- 11.41 microg/g vs. EG, 216.65 +/- 11.10 microg/g) of EG were significantly increased compared with CG. (2) The expression of DMT1 (IRE) and TfR1 of EG was increased. (3) The iron intake was increased in L6 cells treated with SNAP (P < 0.01). (4) Western blot results showed the protein level of both TfR1 and DMT1 (IRE) in SNAP cells were up-regulated, while the expression of FPN1 was down-regulated (P < 0.05). The data suggested that the induced elevation of NO level by exercise lead to the up-regulation of both TfR1 and DMT1 (IRE), which in turn increasing the iron absorption in skeletal muscle.

Objective: To evaluate the cytotoxic effects of three different resin-modified orthodontic band adhesives., Materials and Methods: Three resin-modified orthodontic band adhesives (Bisco Ortho Band Paste LC, Multi-Cure Glass Ionomer Band Cement, and Transbond Plus Light Cure Band Adhesive) were prepared and the samples were extracted in 3 mL of Basal Medium Eagle with 10% newborn calf serum for 24 hours. The L929 cells were plated (25,000 cells/mL) in wells of 96-well dishes and maintained in a humidified incubator for 24 hours at 37 degrees C, 5% CO(2), and 95% air. After 24-hour incubation of the cells, the incubation medium was replaced by the immersed medium in which the samples were stored. Then L929 cells were incubated in contact with eluates for 24 hours. The cell mitochondrial activity was evaluated by the methyltetrazolium test. Twelve wells were used for each specimen, and methyltetrazolium tests were applied two times. The data were statistically analyzed using one-way analysis of variance and Tukey Honestly Significantly Different tests., Results: Results with L929 fibroblasts demonstrated that all freshly prepared resin-modified orthodontic band adhesive materials reduced vital cell numbers (P > .05), in comparison to the control group. Our data demonstrate that all materials showed significant cytotoxicity compared to the control group., Conclusions: The results indicate that all materials showed significant cytotoxicity compared to the control group, and further studies using different test methods are needed for all resin-modified orthodontic band adhesives.

Unlabelled: Chlorhexidine gluconate (CHX) is recommended for a number of clinical procedures and it has been pointed out as a potential cavity cleanser to be applied before adhesive restoration of dental cavities., Objective: As CHX may diffuse through the dentinal tubules to reach a monolayer of odontoblasts that underlies the dentin substrate, this study evaluated the cytotoxic effects of different concentrations of CHX on cultured odontoblast-like cells (MDPC-23)., Material and Methods: Cells were cultured and exposed to CHX solutions at concentrations of 0.06%, 0.12%, 0.2%, 1% and 2%. Pure culture medium (alpha-MEM) and 3% hydrogen peroxide were used as negative and positive control, respectively. After exposing the cultured cells to the controls and CHX solutions for 60 s, 2 h or 60 s with a 24-h recovery period, cell metabolism (MTT assay) and total protein concentration were evaluated. Cell morphology was assessed under scanning electron microscopy. CHX had a dose-dependent toxic effect on the MDPC-23 cells., Results: Statistically significant difference was observed when the cells were exposed to CHX in all periods (p<0.05). Significant difference was also determined for all CHX concentrations (p<0.05). The 60-s exposure time was the least cytotoxic (p<0.05), while exposure to CHX for 60 s with a 24-h recovery period was the most toxic to the cells (p<0.05)., Conclusion: Regardless of the exposure time, all CHX concentrations had a high direct cytotoxic effect to cultured MDPC-23 cells.

Aim: To test the hypothesis that extending the time of a traditional ex vivo cytotoxicity test helps to identify trends in the behaviour of root core materials and sealers, which could ultimately aid in predicting their clinical safety and performance., Methodology: Endodontic sealers and core specimens were initially tested in direct contact with L929 fibroblasts for 72 h. Cell response was estimated by measuring cellular succinate dehydrogenase activity relative to Teflon controls. Cytotoxicity (% of more active cells) was reassessed after 1, 3, 4 and 6 weeks, with the specimens stored in a physiologically balanced salt-solution between tests., Results: Distinct trends in cytotoxicity among both core materials and sealers were observed over the 6-week test. Four of the six sealers and two of the three core materials showed cell viabilities of <30% of Teflon after 6 weeks (>70% cytotoxicity)., Conclusions: The current results suggest that some endodontic materials have an elevated biological risk for extended intervals.

We investigated whether the lower fatigue resistance in smokers than in nonsmokers is caused by a compromised muscle oxidative metabolism. Using calibrated histochemistry, we found no differences in succinate dehydrogenase (SDH) activity, myoglobin concentration, or capillarization in sections of the vastus lateralis muscle between smokers and nonsmokers. The relationship between fatigue resistance and SDH activity in nonsmokers (r = 0.93; p = 0.02) is absent in smokers. This indicates that the lower muscle fatigue resistance of smokers can likely be attributed to causes other than differences in oxidative metabolism and capillarization.

Objectives: Disinfection of the tooth pulp-canal system is imperative to successful endodontic therapy. Yet, studies suggest that 30-50% of current endodontic treatments fail from residual bacterial infection. Photodynamic therapy using red-light chromophores (630 nm) to induce antimicrobial death mediated by generated reactive oxygen species (ROS) has been reported, but red-light also may thermally damage resident tissues. In the current study, we tested the hypothesis that several blue light chromophores (380-500 nm) generate intracellular reactive oxygen species but are not cytotoxic to mammalian cells., Methods: THP1 monocytes were exposed to 10 microM of four chromophores (chlorin e6, pheophorbide-a, pheophorbide-a-PLL, and riboflavin) for 30 min before activation with blue light (27J/cm(2), 60s). After activation, intracellular ROS were measured using a dihydrofluorescein diacetate technique, and cytotoxicity was determined by measuring mitochondrial activity with the MTT method., Results: All photosensitizers produced intracellular ROS levels that were dependent on both the presence of the photosensitizer and blue light exposure. Riboflavin and pheophorbide-a-PLL produced the highest levels of ROS. Photosensitizers except riboflavin exhibited cytotoxicity above 10 microM, and all except pheophorbide-a-PLL were more cytotoxic after blue light irradiation., Significance: The current study demonstrated the possible utility of blue light chromophores as producers of ROS that would be useful for endodontic disinfection.

Purpose: To evaluate the cytotoxicity of three desensitizers, one nonrinse, and one etch-and-rinse adhesive system applied on dentin specimens of different thickness., Materials and Methods: The test materials (A: Admira Protect, B: Gluma Desensitizer, C: Seal&Protect, D: Clearfil Protect Bond, E: Optibond FL) and a positive control (35% H2O2) were applied on 1.0-, 1.5-, and 2.5-mm-thick bovine dentin specimens (each subgroup n = 5) in a dentin barrier test device. The experiments were performed with perfusion (2 ml/h) of the pulpal part of the chamber. The eluates were obtained before (baseline) and 15, 30, 45, 60, and 120 min after application of the adhesives and pipetted onto L-929 fibroblasts. Cytotoxicity of the materials was determined in relation to the baseline value using the MTT assay (succinic dehydrogenase activity). Statistical analysis was performed using ANOVA and Student's t-test., Results: With regard to 1.0-mm dentin specimens, application of Clearfil Protect Bond (D) decreased enzyme activity significantly, while test materials A to C and E were not cytotoxic. However, cytotoxicity of D was limited to up to 15 min and decreased thereafter. Application of the test materials A to E on 1.5- and 2.5-mm dentin samples exhibited no significant cytotoxic effects within 120 min. Generally, ANOVA found significant interactions between the test materials and dentin thickness. However, only for Admira Protect was a significant increase of enzyme activity with increasing dentin thickness observed., Conclusion: Desensitizing agents might exhibit cytotoxic potential when applied on dentin less than 1.0 mm thick. The tested desensitizers and the adhesive systems caused similar effects, in which cytotoxicty might be influenced by the duration of perfusion and dentin thickness.

Hyperhomocysteinemia (HHcy) is a critical independent risk factor for cardiovascular diseases. However, to date, no satisfactory strategies to prevent HHcy exist. Since homocysteine (Hcy) and endogenous H2S are both metabolites of sulfur-containing amino acids, we aimed to investigate whether a metabolic product of Hcy and H2S, may antagonize in part the cardiovascular effects of Hcy. In the HHcy rat model injected subcutaneously with Hcy for 3 weeks, H2S levels and the H2S-generating enzyme cystathionine gamma lyase (CSE) activity in the myocardium were decreased. The intraperitoneal injection of H2S gas saturation solution significantly reduced plasma total Hcy (tHcy) concentration and decreased lipid peroxidation formation (i.e., lowered manodialdehyde and conjugated diene levels in myocardia and plasma). The activities of myocardial mitochondrial respiratory enzymes succinate dehydrogenase, cytochrome oxidase, and manganese superoxide dismutase, related to reactive oxygen species metabolism, were significantly dysfunctional in HHcy rats. The H2S administration restored the level of enzyme activities and accelerated the scavenging of H2O2 and superoxide anion generated by Hcy in isolated mitochondria. The H2S treatment also inhibited the expression of glucose-regulated protein 78, a marker of endoplasmic reticulum (ER) stress, induced by Hcy in vivo and in vitro. Thus, HHcy impaired the myocardial CSE/H2S pathway, and the administration of H2S protected the myocardium from oxidative and ER stress induced by HHcy, which suggests that an endogenous metabolic balance of sulfur-containing amino acids may be a novel strategy for treatment of HHcy.

The present investigation was an attempt to evaluate the effect of aflatoxin on biochemical and histopathological changes in the epididymis of mice and its possible amelioration on pre-treatment with vitamin E. Adult male albino mice were orally administered with 25 and 50 mg of aflatoxin/animal/day (750 and 1500 mg/kg body weight) for 45 days. Epididymis was isolated and processed for biochemical analysis. As compared with the control, absolute and relative epididymal weights were significantly reduced in aflatoxin-treated mice. Aflatoxin treatment caused significant, dose-dependent reduction in protein and sialic acid contents in caput and cauda epididymis than that of vehicle control. While activities of succinic dehydrogenase and adenosine triphosphatase were significantly reduced, acid phosphatase activity was significantly higher in caput and cauda epididymis of aflatoxin-treated mice than that of vehicle control. Pyknosis of epithelial cell nuclei, disorganization of epithelium, clumping of stereocilia and lumen devoid of sperms in caput and cauda epididymis were observed. Thus, pre-treatment with vitamin E (2 mg/0.2 mL olive oil/ animal/day) significantly ameliorated aflatoxin-induced changes, measured by biochemical and histopathological parameters.

Trypanosoma brucei, a protozoan parasite causing sleeping sickness, is transmitted by the tsetse fly and undergoes a complex lifecycle including several defined stages within the insect vector and its mammalian host. In the latter, differentiation from the long slender to the short stumpy form is induced by a yet unknown factor of trypanosomal origin. Here we describe that some thiazolidinediones are also able to induce differentiation. In higher eukaryotes, thiazolidinediones are involved in metabolism and differentiation processes mainly by binding to the intracellular receptor peroxisome proliferator activated receptor gamma. Our studies focus on the effects of troglitazone on bloodstream form trypanosomes. Differentiation was monitored using mitochondrial markers (membrane potential, succinate dehydrogenase activity, inhibition of oxygen uptake by KCN, amount of cytochrome transcripts), morphological changes (Transmission EM and light microscopy), and transformation experiments (loss of the Variant Surface Glycoprotein coat and increase of dihydroliponamide dehydrogenase activity). To further investigate the mechanisms responsible for these changes, microarray analyses were performed, showing an upregulation of expression site associated gene 8 (ESAG8), a potential differentiation regulator.

Mitochondrial toxicity limits nucleoside reverse transcriptase inhibitors (NRTIs) for acquired immune deficiency syndrome. NRTI triphosphates, the active moieties, inhibit human immunodeficiency virus reverse transcriptase and eukaryotic mitochondrial DNA polymerase pol-gamma. NRTI phosphorylation seems to correlate with mitochondrial toxicity, but experimental evidence is lacking. Transgenic mice (TGs) with cardiac overexpression of thymidine kinase isoforms (mitochondrial TK2 and cytoplasmic TK1) were used to study NRTI mitochondrial toxicity. Echocardiography and nuclear magnetic resonance imaging defined cardiac performance and structure. TK gene copy and enzyme activity, mitochondrial (mt) DNA and polypeptide abundance, succinate dehydrogenase and cytochrome oxidase histochemistry, and electron microscopy correlated with transgenesis, mitochondrial structure, and biogenesis. Antiretroviral combinations simulated therapy. Untreated hTK1 or TK2 TGs exhibited normal left ventricle mass. In TK2 TGs, cardiac TK2 gene copy doubled, activity increased 300-fold, and mtDNA abundance doubled. Abundance of the 17-kd subunit of complex I, succinate dehydrogenase histochemical activity, and cristae density increased. NRTIs increased left ventricle mass 20% in TK2 TGs. TK activity increased 3 logs in hTK1 TGs, but no cardiac phenotype resulted. NRTIs abrogated functional effects of transgenically increased TK2 activity but had no effect on TK2 mtDNA abundance. Thus, NRTI mitochondrial phosphorylation by TK2 is integral to clinical NRTI mitochondrial toxicity.

3-Nitropropionic acid (3-NP) is a well known fungic toxin causing neurotoxicity. Systemic administration of 3-NP causes motor and cognitive deficits that are associated with excessive free radical generation. Recently, curcumin has been implicated as a neuroprotectant in the treatment of various neurological disorders. The present study was designed to investigate the effects of curcumin in 3-NP-induced cognitive impairment and oxidative stress in rats. Curcumin, a potent antioxidant of dietary polyphenol, containing a standardized extract of Curcuma longa root (Zingiberaceae), has been reported to possess free radical scavenging, iron chelating and antiinflammatory activities. Intraperitoneal administration of 3-NP (20 mg/kg for 4 days) showed loss in body weight, declined motor function, poor retention of memory and changes in oxidative stress (lipid peroxidation, reduced glutathione and nitrite level) parameters in brain. Chronic treatment with curcumin (10, 20 and 50 mg/kg, p.o.) once daily for a period of 8 days beginning 4 days prior to 3-NP administration dose-dependently improved the 3-NP-induced motor and cognitive impairment. Biochemical analysis revealed that curcumin administration significantly attenuated 3-NP-induced oxidative stress (lipid peroxidation estimation, reduced glutathione and nitrite activity) in the brains of rats. It also significantly restored the decreased succinate dehydrogenase activity. The results of the present study clearly indicate that curcumin by its antioxidant activity showed neuroprotection against 3-NP-induced behavioral and biochemical alteration., ((c) 2007 Prous Science. All rights reserved.)

The objective of this study was to evaluate the cytotoxicity of three endodontic sealers (AH Plus/Maillefer-Dentsply, Epiphany/Pentron, GuttaFlow, Coltene-Whaledent). Materials were mixed according to the manufacturer instructions and packed into Teflon molds (10 x 1 mm). For cytotoxicity testing (MTT method), the specimens were placed in contact with cultured cells, then evaluated at two subsequent time points (24 or 72 h). In addition to testing the mixed materials, 5 microl of primer liquid (GuttaFlow and Epiphany) and resin solvents (HEMA, ethanol, sterile water, or acetone) were added directly in culture for 24 and 72 h. The results showed that most materials pose significant cytotoxic risks and that cytotoxicity generally increased with time. At 72 h, GuttaFlow became significantly less toxic than AH Plus, Epiphany sealer, and Resilon. The current results support the need to continue to develop better endodontic sealers that combine the excellent sealing and bonding properties of resins with acceptable biological properties for endodontic applications.

Unlabelled: Recently, a resin-based calcium phosphate cement (RCPC) has been reported as a remineralizing pulp-capping or lining cement. RCPC consists mainly of tetracalcium and dicalcium phosphates, ethoxylated bisphenol A dimethacrylate and pyromellitic glycerol dimethacrylate monomers and photo- and chemical initiators., Objectives: Here, the cytotoxic effects of RCPC were evaluated. The hypothesis was that RCPC induced only minor cytotoxic response in immortalized murine odontoblast and pulp cells, comparable to that produced by similar dimethacrylates due to unpolymerized dimethacrylate monomer present after curing., Methods: Cytotoxicity was determined following the changes in cell succinate dehydrogenase activity after 24 h exposure to the cement components and after a 24 h recovery period. A fourfold range of concentrations was tested of the monomers, the eluate of cured RCPC leached in Dulbecco's modified Eagle's medium, and crushed cured cement in dimethyl sulfoxide., Results: The monomers themselves had cytotoxicities similar to those reported for other dimethacrylates, although they are significantly less toxic than Bis-GMA. Differential cell sensitivity was demonstrated, with the pulp cells having greater sensitivity to the unpolymerized monomer than the odontoblast-like cells. The leached components have cytotoxicity similar to that of the free monomers. The crushed material demonstrated no apparent cytotoxicity at the dilutions tested., Significance: These data demonstrate that RCPC has an in vitro cytotoxicity that is comparable to other materials containing dimethacrylate monomers and suggest that the material may be suitable for use in dental restorations. The data also indicate that the pulp cells appear more sensitive to dimethacrylates than the odontoblasts.

Several lines of research suggest that mitochondria play a role in the etiopathogenesis of diabetic cardiomyopathy, although the mechanisms involved are still debated. In the present study, we report that State 3 oxygen consumption decreases by approximately 35% with glutamate and by approximately 30% with succinate in mitochondria from diabetic rat hearts compared to controls. In these mitochondria the enzymatic activities of complex I and complex II are also decreased to a comparable extent. Western blot analysis of mitochondrial protein pattern using antibodies recognizing proteins modified by the lipid peroxidation product 4-hydroxynonenal indicates the FAD-containing subunit of succinate dehydrogenase as one of the targets of this highly reactive aldehyde. In rats diabetic for 6 or 12 weeks, insulin supplementation for 2 weeks decreases the level of protein modified by 4-hydroxynonenal and restores mitochondrial respiration and enzyme activity to control level. Taken together, these results: (1) indicate that 4-hydroxynonenal is endogenously produced within diabetic mitochondria and forms an adduct with selective mitochondrial proteins, (2) identify one of these proteins as a subunit of succinate dehydrogenase, and (3) provide strong evidence that insulin treatment can reverse and ameliorate free radical damage and mitochondrial function under diabetic conditions.

Malonate, a reversible inhibitor of the mitochondrial enzyme succinate dehydrogenase, is frequently used as a model neurotoxin to produce lesion of the nigrostriatal dopaminergic system in animals due to particular sensitivity of dopamine neurons to mild energy impairment. This model of neurotoxicity was applied in our study to explore neuroprotective potential of 1,2,3,4-tetrahydroisoquinoline (TIQ), an endo- and exogenous substance whose function in the mammalian brain, despite extensive studies, has not been elucidated so far. Injection of malonate at a dose of 3 mumol unilaterally into the rat left medial forebrain bundle resulted in the 54% decrease in dopamine (DA) concentration in the ipsilateral striatum and, depending on the examined striatum regions, caused 24-44% reduction in [3H]GBR12,935 binding to the dopamine transporter (DAT). TIQ (50 mg/kg i.p.) administered 4 h before malonate infusion and next once daily for successive 7 days prevented both these effects of malonate. Such TIQ treatment restored DA content and DAT binding almost to the control level. The results of the present study indicate that TIQ may act as a neuroprotective agent in the rat brain. An inhibition of the enzymatic activities of monoamine oxidase and gamma-glutamyl transpeptidase as well as an increase in the striatal levels of glutathione and nitric oxide found after TIQ administration and reported in our earlier studies are considered to be potential factors that may be involved in the TIQ-mediated protection of dopamine terminals from malonate toxicity.

The inhibitor of mitochondrial enzyme succinate dehydrogenase, 3-nitropropionic acid (3-NPA), induces cellular energy deficit followed by oxidative stress, secondary excitotoxicity and neuronal degeneration. The fast activation of Jun and Fos proteins and other proteins encoding inducible transcription factors (ITFs) occurs in most tissues upon exposure to a variety of stressors including exposure to mitochondrial inhibitors. However, the consequences of this activation can differ dramatically in different organs. For example, while activation of the same ITFs may lead to apoptosis and necrosis in neurons it may stimulate liver regeneration. Here, we report the alterations in mRNAs levels of c-Fos, JunB, and Krox20 proteins induced in the rat brain and liver by the acute exposure to 3-NPA at 30 mg/kg, s.c. While the increase of c-fos transcripts was observed in both the hippocampus and liver, the junb transcript increased in the hippocampus but decreased in the liver. No changes were observed in krox-20 mRNA in the hippocampus. Interestingly, there was a large variation in krox-20 mRNA levels in the liver among animals within the same experimental group. In conclusion, out of the three ITFs transcripts examined here junb may activate different pathways depending on the tissue as indicated by differential responses to mitochondrial inhibition in the hippocampus and liver.

Objective: To investigate effects of Chinese herb compound on myocardial SDH, ATP-ase and energy reserves in tail-suspended rats., Method: Male SD rats were randomly divided into three groups (n=10 each): (A) normal control group; (B) tail-suspended group; (C) tail-suspended + Chinese Medical herb compound group. Rats in group B and C were tail-suspended (-30 degrees) for 5 d to simulate weightlessness. All rats B were decapitated after the experiment. Myocardial SDH (method of Anderson N-BT), ATP-ase (method of Wachstein and Meisel) and energy reserves (method of HPLC) were examined., Result: Compared with rats in groups A and C, SDH activity increased, SDH staining deepened, value of OD SDH enhanced, ATP-ase activity and OD value increased and enhanced significantly (P<0.01) but value of myocardial energy reserves decreased in group B rats., Conclusion: Tail-suspension strengthens compensatory oxidation metabolism of cardiac muscle and activates SDH and ATP-ase, at the same time decrease, myocardial energy reserves. Normal are maintained the low level of metabolism by the medical herb compound used which shows a protecting effects through mitigation, tranguilization and replenishment of Qi.

The objectives of this study were to evaluate the cytotoxicity and sealing properties of four classes of endodontic sealers (PCS/Kerr, RoekoSeal/Roeko, TopSeal/Dentsply, and EndoREZ/Ultradent). For cytotoxicity testing (MTT method), the materials were either placed immediately in contact with cultured cells or 24 h after setting, then evaluated at three subsequent time points (24 h, 48 h, or 1 wk). For the leakage study, extracted human roots were obturated with acrylic cones and sealers and immersed for 48 h into rhodamine-labeled lipopolysaccharide. The roots were then observed under a confocal laser scanning microscope to estimate (semiquantitatively) the presence of the rhodamine-lipopolysaccharide (LPS) inside the canal. The results showed that cytotoxicity generally increased with time, and that most materials pose significant cytotoxic risks, particularly in the freshly mixed condition. Further, all materials showed significant leakage although there was large variation among teeth. Overall, the silicon-based material (Roeko Seal) was less cytotoxic and more effective in sealing root canals against LPS leakage than other materials.

Manganese (Mn) is known to induce mitochondrial dysfunction in excessive dose; however the mechanisms underlying its action are not elucidated clearly. To determine if Mn2+ can act directly on mitochondria or indirectly by producing reactive oxygen species (ROS), isolated mitochondria were exposed to different concentration of Mn2+ (5, 50, 500, 1000 microM). ROS generation, respiratory control ratio (RCR), mitochondrial membrane potential (MMP) and respiratory chain complexes activities were investigated. Dose-dependent inhibition of respiratory chain complexes and induction of ROS were observed; these changes were paralleled by decreasing of respiratory control ratio (RCR) both with succinate or glutamate + malate. Further investigation indicated that the membrane potential determined by Rhodamine123 release decreased after MnCl2 exposure at 1000 microM. In addition, effects of the antioxidants NAC (500 microM), GSH (500 microM) and Vitamin C (500 microM) were studied at 500 microM Mn2+. The results indicate that the effect of Mn2+ exposure on respiratory chain is not site-specific, and antioxidants can protect the mitochondria function by reducing the formation of free radicals.

There is evidence of hepatotoxic effects caused by Perchloroethylene (PCE), presumably due to reactive metabolic intermediates; lipid peroxidation is under study as a potential mechanism of toxicity. We aimed to verify if PCE levels comparable to those reached in the blood of exposed subjects can cause cell damage and lipid peroxidation. The association of PCE with lipid peroxidation inducing drugs (cyclosporine A, valproic acid and amiodarone) was also tested on rat isolated hepatocytes. AST and LDH release, MTT test and lipid peroxidation assay showed that PCE determines dose-dependent effects on rat isolated hepatocytes. The toxic potential resulting from our data would be valproic acid < cyclosporine A < amiodarone. While valproic acid and cyclosporine caused a mild toxicity, the effects of amiodarone were more severe; in particular, the association of PCE with amiodarone showed a clear additive effect. The role of lipid peroxidation in the liver toxicity exerted by the tested compounds was confirmed by our data, and resulted relevant after treatment of cells with amiodarone and PCE. Extrapolating these results to human, we can suggest that a subject professionally exposed to PCE, who chronically assumes a lipid peroxidation inducing drug like amiodarone, may be potentially exposed to a higher risk of liver toxicity.

Statement of Problem: The biocompatibility of new dental ceramics has not been assessed with the same scrutiny as has been applied to alloys and composites. Yet, the biocompatibility of ceramics is critical to the long-term success of dental prostheses because ceramics are in close contact with oral tissues for extended periods., Material and Methods: Five dental ceramics (2 traditional feldspathic veneer porcelains [Vita Omega and Duceragold], 2 lithium disilicate pressable materials [Stylepress and Empress-2], and a pressable leucite-based material [Empress-1]) were tested for their ability to alter cellular mitochondrial dehydrogenase activity after fabrication using a tetrazolium assay, after aging for 2 weeks in a biologic solution and after post-aging polishing with either a fine diamond or diamond polishing paste. Cellular responses were compared with polytetrafluoroethylene controls (analysis of variance, Tukey pairwise post-hoc comparison, alpha=.05)., Results: The feldspathic porcelains caused only mild (<25% of controls) mitochondrial suppression regardless of aging or polishing. The pressable leucite-based material initially caused a 5% stimulation (not significant) of mitochondrial activity, which decreased significantly (P<.05) by 30% with aging to levels comparable to the feldspathic porcelains, and did not change with polishing. Both lithium disilicate materials caused an initial suppression of mitochondrial activity that decreased significantly with aging, but Empress-2 was severely cytotoxic initially (<20% of controls, P<.01), and became more cytotoxic again after polishing. Stylepress was less cytotoxic initially (85% of controls, not significant) and did not become cytotoxic again after polishing., Conclusions: Dental ceramics are not equivalent in their in vitro biologic effects, even within the same class of material, and biologic safety should not be assumed. Most ceramics caused only mild in vitro suppression of cell function to levels that would be acceptable on the basis of standards used to evaluate alloys and composites. However, 1 Li-disilicate material (Empress-2) exhibited cytotoxicity that would not be deemed biologically acceptable on the basis of prevailing empirical standards for dental alloys and composites.

Purpose: To determine, in vitro, cytotoxicity and cell adhesion on 3 different implant surfaces., Materials and Methods: All samples had machined surfaces, but they were subjected to different cleaning procedures, which produced 3 different surface chemistries. One of the samples was "as-produced" from the machining tools. The other samples were subjected to partial and total cleaning routines. Cytotoxicity was evaluated using mouse fibroblast cultures, and cell adhesion was evaluated with osteoblast-like SaOS-2 cells., Results: The "as-produced" sample showed a pronounced surface contamination by lubricating oils. For partially and totally cleaned samples, an increasing amount of titanium and a decreasing carbon/titanium ratio was observed as cleaning became more complete., Discussion: Differences in surface chemistry such as those normally found on titanium implant surfaces (see part 1 of this series) can lead to those same effects which, in in vitro experiments, are normally accounted for in terms of surface topography alone., Conclusion: Effects related to surface chemistry can operate over and above surface topography, making it impossible, without proper characterization, to make definite statements about the role of topography alone.

We studied the role of mitochondria in insulin-induced inactivation of protein tyrosine phosphatases in the liver. The mitochondrial respiratory chain is an insulin-sensitive source of H(2)O(2)that acts as a physiological inhibitor of protein tyrosine phosphatases. Succinate dehydrogenase plays a key role in insulin-stimulated generation of H(2)O(2)and inactivation of liver protein tyrosine phosphatases.

Approximately 50% of the world's population carries Helicobacter pylori, a gastric bacterial pathogen linked to diseases including gastritis, ulcers and gastric cancer. Chemotherapies are being routinely used to treat systemic H. pylori infection. The common regimens consist of proton pump inhibitors (PPIs) or ranitidine bismuth citrate (RBC) and two antibiotics. Although these regimens efficiently eradicate H. pylori, the emergence of antibiotic-resistant H. pylori strains, their severe side effects and high costs are major drawbacks of these treatments. More efficient, economic and friendly drugs need to be developed. Fumarate reductase (FRD) catalyses the reduction of fumarate to succinate in the Krebs cycle and is also a key enzyme in anaerobic respiration with fumarate as the terminal electron acceptor for many facultative bacteria. H. pylori FRD contains three subunits, FrdA, FrdB and FrdC. Genome analysis and experimental evidence indicate that this enzyme appears to play an important role in the energy metabolism of H. pylori. In addition, FRD is essential for the colonisation of H. pylori in the acidic stomach as demonstrated in the mouse model of infection. Furthermore, three FRD inhibitors used to cure helminthic infection in animals and humans have both inhibitory and bactericidal effects on H. pylori. These lines of evidence indicate that FRD may be a promising chemotherapeutic target. Given that FrdA is strongly immunogenic in the sera from H. pylori-positive patients, this protein may also be used as a candidate for the development of an anti-H. pylori vaccine.

Poisoning of rats with sodium nitrite has been found to decrease Na/K-ATPase and succinate dehydrogenase activity in the small intestinal villi.

The activity levels of succinate dehydrogenase (SDH) and glucose-6-phosphate dehydrogenase (G6PD) were assessed in various tissues of Cyprinus carpio var communis which had been exposed to lethal concentrations of group-II pyrethroids (deltamethrin, cypermethrin, fenvalerate and fluvalinate) for a period of 72 h. The results indicated a steady decrease in SDH activity with a concomitant increase in G6PD activity. The decreased SDH activity indicated inhibition of SDH at mitochondrial level and the increased G6PD activity an enhancement of an alternative pathway of carbohydrate metabolism, viz the hexose monophosphate shunt (HMP) or pentose phosphate pathway as a biochemical adaptation to overcome the toxic stress.

Our previous studies have shown that chalcones exhibit potent antileishmanial and antimalarial activities in vitro and in vivo. Preliminary studies showed that these compounds destroyed the ultrastructure of Leishmania parasite mitochondria and inhibited the respiration and the activity of mitochondrial dehydrogenases of Leishmania parasites. The present study was designed to further investigate the mechanism of action of chalcones, focusing on the parasite respiratory chain. The data show that licochalcone A inhibited the activity of fumarate reductase (FRD) in the permeabilized Leishmania major promastigote and in the parasite mitochondria, and it also inhibited solubilized FRD and a purified FRD from L. donovani. Two other chalcones, 2,4-dimethoxy-4'-allyloxychalcone (24m4ac) and 2,4-dimethoxy-4'-butoxychalcone (24mbc), also exhibited inhibitory effects on the activity of solubilized FRD in L. major promastigotes. Although licochalcone A inhibited the activities of succinate dehydrogenase (SDH), NADH dehydrogenase (NDH), and succinate- and NADH-cytochrome c reductases in the parasite mitochondria, the 50% inhibitory concentrations (IC(50)) of licochalcone A for these enzymes were at least 20 times higher than that for FRD. The IC(50) of licochalcone A for SDH and NDH in human peripheral blood mononuclear cells were at least 70 times higher than that for FRD. These findings indicate that FRD, one of the enzymes of the parasite respiratory chain, might be the specific target for the chalcones tested. Since FRD exists in the Leishmania parasite and does not exist in mammalian cells, it could be an excellent target for antiprotozoal drugs.

In humans or animals, symptoms of mitochondrial energy dysfunction may be produced by mutations or inborn errors of the necessary enzymes, as well as by enzyme inhibitors or uncouplers of the oxidative phosphorylation process. 3-Nitropropionic acid (3-NPA) is a toxin that is sometimes produced on moldy crops (sugarcane, peanuts, etc.) in amounts sufficient to cause severe neuromuscular disorders when consumed by humans. In vitro, 3-NPA irreversibly inactivates SDH, a Complex II respiratory enzyme important for mitochondrial energy production. We have been studying biomarkers of 3-NPA exposure in the expectation that such markers may be useful in the screening process to identify neuroprotective agents against neurotoxicity produced by mitochondrial energy dysfunction. Animals were sacrificed at various times after 3-NPA exposure for histochemical visualization of SDH activity and measurement of immediate postmortem rectal temperature. 3-NPA-treated rats experienced progressive hypothermia that reached a loss of 3 degrees C or more in core body temperature by three hours after dosing. The optical density of the SDH stain in brain was reduced, following a similar time course, most prominently in the cerebellum and least sharply in the thalamus. Some rats were given injections of L-carnitine (an enhancer of fatty acid transport) either alone, or as a pretreatment prior to a dose of 3-NPA. Although L-carnitine deficiency by itself can produce mitochondrial dysfunction, pretreatment with L-carnitine was of limited efficacy at overcoming the effects of 3-NPA on either body temperature or quantitative SDH histochemistry. Body temperature and SDH histochemistry may be useful biomarkers for evaluating the efficacy of neuroprotective agents against lower doses of 3-NPA, against other pharmacological models of mitochondrial dysfunction, or even against genetic mitochondrial diseases.

Objective: The objective of this study is to investigate the mechanism of acute trauma of endothelium after injection of Pingyangmycin., Methods: A total of 42 adult Wistar rats were divided randomly into experimental groups (24), positive control groups (12) and normal control group (6), and the rats in the experimental or the positive control groups were injected with Pingyangmycin or sodium morrhuate into the mesenteric veins respectively, and then the enzyme activity of hepatic endothelial cells and hepatocytes was examined histochemically 0.5, 1, 2, 4, 8 and 24 hours after injection., Results: After injection, the activity of 5'-nucleinase(5'-N) in hepatic endothelial cells and that of lactic dehydrogenase (LDH) and succinodehydrogenase (SDH) in hepatocytes decreased gradually, but that injected Pingyangmycin was less than that injected sodium morrhuate., Conclusion: The trauma caused by Pingyangmycin is less than that caused by sodium morrhuate, but the reaction of trauma caused by both is nonspecific.

L-Carnitine (LC) plays an important regulatory role in the mitochondrial transport of long chain free fatty acids (FFA). 3-Nitropropionic acid (3-NPA) is known to induce cellular energy deficit and oxidative stress-related neurotoxicity via an irreversible inhibition of mitochondrial succinate dehydrogenase (SDH). In the present study, activity of SDH was measured in order to evaluate neuroprotective effects of LC against the 3-NPA-induced neurotoxicity. Male, CD Sprague-Dawley rats, three months old, were injected with either 50 or 100 mg/kg of LC, i.p., 30 min prior to 3-NPA (30 mg/kg, s.c.) or with 3-NPA alone. The activity of brain SDH was quantified spectrophotometrically in caudate nucleus (CN), frontal cortex (FC), and hippocampus (HIP) 60 min after the 3-NPA injection. The SDH activity in the animals treated with 3-NPA alone was 38% (CN), 50% (FC), and 36% (HIP) that of saline controls. Pretreatment with LC prior to 3-NPA injection attenuated decreases of SDH activity by approximately 15 and 29% (LC low and high dose, respectively). Despite the attenuation of SDH inhibition, the activity of SDH in these regions remained significantly lower in treated than in control rats (p < 0.05). It appears that the protective effect of LC against 3-NPA-induced oxidative stress cannot be explained by the direct action of LC to interfere with the SDH inhibition but are rather achieved by LC actions downstream of the SDH inhibition.

The purpose of this study was to evaluate the interactive toxicity of ethanol with potassium dichromate (K2Cr2O7-chromium). Young, male Wistar rats (100-120 g) were divided into four groups of five or six animals each and were dosed, through water, with 10% ethanol (vol./vol.) or 25 ppm chromium or were dosed with a combination of ethanol+chromium at the same concentrations for a period of 22 weeks ad libitum and were maintained on normal diet. Control animals were maintained on a normal diet and water for the same period. The serum succinate dehydrogenase and liver total triglyceride levels were significantly reduced in the three treated groups. The serum alkaline phosphatase levels were significantly reduced in ethanol-treated rats, and there was no significant change in the acid phosphatase activity. Serum aspartate and alanine aminotransferase levels in the three treated groups were significantly increased. The liver glycogen significantly decreased in both the ethanol-treated and the chromium-treated rats. There was a significant increase in liver total cholesterol levels in chromium-treated rats. Total glutathione levels were significantly decreased in the livers of ethanol-treated and ethanol+chromium-treated rats. To further substantiate these findings, a histological examination of the liver and kidneys was undertaken. The livers of alcohol-treated animals showed altered hepatic architecture in the centrilobular and periportal areas, with increased sinusoidal space (space of Disse), vacuolation, and necrosis of hepatocytes. Similar changes were observed in a histological examination of the livers of chromium-treated rats, except that the damage to the hepatocytes was more confined to the periportal area. Moreover, histological examination of the livers of ethanol+chromium-treated rats revealed uniform damage in the centrilobular and periportal areas, as was observed in the groups treated either with ethanol or chromium. The histological examination of the kidneys in the three treated groups revealed significant damage to the renal tubules and Bowman's capsule, which showed vacuolation and degeneration of the basement membrane. These findings correlate well with the serum enzyme levels found in the treated groups. It is evident from this study that chronic ethanol consumption sensitizes the liver to the toxic action of agents such as chromium. It leads to impairment of the biochemical functions in the liver, and it causes liver and kidney damage. Long-term simultaneous exposure to ethanol and chromium may cause severe health problems in people who are alcoholics and work in chrome-plating and leather-tanning industries.

Objective: Resin monomers such as HEMA (2-hydroxyethyl methacrylate) can be released from restorative materials and diffuse into the tooth pulp over long periods of time. Although the short-term toxicity of resin monomers has been well documented, little is known about the risk for chronic toxicity resulting from low concentrations of resins. Thus, the hypothesis tested in this study was that sub-lethal concentrations of HEMA alter the functions of macrophages after long-term exposure., Methods: Human THP-1 monocyte-macrophages were exposed to concentrations of HEMA between 0 and 1.5 mmol/l for up to 6 weeks. Cellular proliferation was measured by a hemocytometer with trypan-blue dye exclusion. Mitochondrial activity was measured by the MTT assay, and total cellular protein was measured using the bicinchoninic acid assay., Results: Macrophage proliferation was inhibited 40-50% (significant, p < 0.05) by as little as 0.75 mmol/l after 1 week of exposure. Inhibition of proliferation remained constant after 1 week. The total protein per cell increased by as much as 80% (significant, p < 0.05) after 2 weeks and remained elevated through 6 weeks. Mitochondrial activity per cell increased 60-80% (significant, p < 0.05) after 2 weeks, then decreased. However, mitochondrial activity remained significantly elevated above controls through 6 weeks., Significance: Findings from the current study indicate that 6-week exposures of monocytes to HEMA alter their proliferation and other activities at concentrations substantially lower than previously reported. This is particularly relevant in light of evidence that such concentrations have been previously shown to come through dentin by diffusion.

The effect of exposure to sublethal concentrations of the organophosphate pesticide, quinalphos (1.12, 0.22 mg/l) on biochemical parameters of muscle and enzyme activities in brain, liver and kidney of the Indian major carp, Labeo rohita was studied after 15, 30 and 45 days. The muscle protein and RNA levels decreased whereas DNA levels and acid phosphatase were elevated. Similarly, alkaline phosphatase was depleted. The brain acetyl cholinesterase activity was decreased most (-75.43%) in 1.12 mg/l concentration over a period of 45 days. Lactic dehydrogenase levels in brain and liver were elevated whereas in the kidney they were inhibited. Succinic dehydrogenase and adenosine triphosphatase activities were depleted in brain, liver and kidney. The effects have been discussed for different organ tissues in relation to the pesticide.