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

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Query: EC:1.3.5.1 (succinate dehydrogenase)
8,177 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In the presented study the influence of freezing and freeze-drying on enzyme activity is described. Attention is paid to 16 enzymes which can be used for quantitative enzyme histochemical techniques. With the exception of succinate dehydrogenase only, no significant inactivation during freezing and freeze-drying procedures could be demonstrated with lactate dehydrogenase, malate dehydrogenase (NAD+), malate dehydrogenase (decarboxylating) (NADP+), isocitrate dehydrogenase (NADP+), glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, NADH-oxydoreductase, mitochondrial glycerol-3-phosphate dehydrogenase, cytochrome c oxidase, phosphoglucomutase, glucosephosphate isomerase, glucose-6-phosphatase, acid phosphatase, beta-glucuronidase and non specific aryl esterase. Therefore, the results supply a sound foundation for those quantitative enzyme histochemical techniques in which tissue specimens are frozen or frozen-dried before enzyme estimations are performed.
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PMID:The influence of freezing and freeze-drying of tissue specimens on enzyme activity. 87 Apr 61

Structural mitochondrial damage accompanies the cytotoxic effects of several drugs including tumor necrosis factor (TNF). Using various inhibitors of mitochondrial electron transport we have investigated the mechanism of TNF-mediated cytotoxicity in L929 and WEHI 164 clone 13 mouse fibrosarcoma cells. Inhibitors with different sites of action modulated TNF cytotoxicity, however, with contrasting effects on final cell viability. Inhibition of mitochondrial electron transport at complex III (cytochrome c reductase) by antimycin A resulted in a marked potentiation of TNF-mediated injury. In contrast, when the electron flow to ubiquinone was blocked, either at complex I (NADH-ubiquinone oxidoreductase) with amytal or at complex II (succinate-ubiquinone reductase) with thenoyltrifluoroacetone, cells were markedly protected against TNF cytotoxicity. Neither uncouplers nor inhibitors of oxidative phosphorylation nor complex IV (cytochrome c oxidase) inhibitors significantly interfered with TNF-mediated effects, ruling out the involvement of energy-coupled phenomena. In addition, the toxic effects of TNF were counteracted by the addition of antioxidants and iron chelators. Furthermore, we analyzed the direct effect of TNF on mitochondrial morphology and functions. Treatment of L929 cells with TNF led to an early degeneration of the mitochondrial ultrastructure without any pronounced damage of other cellular organelles. Analysis of the mitochondrial electron flow revealed that TNF treatment led to a rapid inhibition of the mitochondria to oxidize succinate and NADH-linked substrates. The inhibition of electron transport was dose-dependent and became readily detectable 60 min after the start of TNF treatment, thus preceding the onset of cell death by at least 3-6 h. In contrast, only minor effects were observed on complex IV activity. The different effects observed with the mitochondrial respiratory chain inhibitors provide suggestive evidence that mitochondrial production of oxygen radicals mainly generated at the ubisemiquinone site is a causal mechanism of TNF cytotoxicity. This conclusion is further supported by the protective effect of antioxidants as well as the selective pattern of damage of mitochondrial chain components and characteristic alterations of the mitochondrial ultrastructure.
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PMID:Cytotoxic activity of tumor necrosis factor is mediated by early damage of mitochondrial functions. Evidence for the involvement of mitochondrial radical generation. 131 87

We have studied cytochrome c oxidase (COX) deficient muscle fibre segments in 6 patients with mitochondrial myopathy and deletions of mitochondrial DNA (mtDNA). The distribution of transcripts of normal and mutated mtDNA in skeletal muscle sections was studied by in situ hybridization. The results were compared with the enzyme histochemical activity of COX and the immunohistochemical distribution of mtDNA encoded and nuclear DNA encoded subunits of COX. In all cases a proportion of the muscle fibres (less than 1-30% of the fibres in cross-sections) had low COX activity and high activity of succinate dehydrogenase (COX deficient muscle fibres). Transcripts of normal and deleted mtDNA showed the same distribution within the tissue as the corresponding mtDNA, indicating that the deleted mtDNA is transcribed. The COX deficient muscle fibres showed accumulation of transcripts of deleted mtDNA, which had a similar distribution as the accumulated mitochondria within these fibres. With few exceptions, there was a low level of transcripts of normal mtDNA in these COX deficient fibres. Immunohistochemical analysis revealed low levels of immunoreactive material using antiserum to the mtDNA encoded subunits II/III as well as the nuclear DNA encoded subunit IV of COX in all COX deficient muscle fibres. The fraction of deleted mtDNA in muscle ranged from 43 to 87%. There was no correlation between the proportion of COX deficient muscle fibres and the fraction of deleted mtDNA. In 2 cases the deletion did not involve any COX gene. One of these cases had 87% deleted mtDNA but less than 1% COX deficient muscle fibres.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Mitochondrial DNA deletions and cytochrome c oxidase deficiency in muscle fibres. 132 95

A statistical analysis of mitochondrial abnormality of aging in human skeletal muscle fibers was performed. Sixty one muscle samples were obtained from patients with acute medical illness autopsied strictly within 2 hours after death, or with orthopedic or surgical diseases biopsied with informed consents. The patients aged from 16 to 89, averaging 58 +/- 21 years in males and 21 to 92, averaging 55 +/- 20 years in females. Sections were stained by modified Gomori's trichrome, succinate dehydrogenase and cytochrome c oxidase-negative [CCO(-)] fibers approximately in 10,000 fibers in each muscle were evaluated. Both RRF and CCO (-) fibers were not observed below the fourth decade, but sequentially increased with age, especially after the seventh decade. The incidence of CCO (-) fibers was higher than that of RRF. RRF did not necessarily correspond to CCO (-) fibers. The present quantitative pathological result is a useful tool to evaluate the mitochondrial function in fresh human skeletal muscles by the age.
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PMID:[Quantitative skeletal muscle pathology of aging regarding ragged-red fibers and cytochrome c oxidase-negative fibers]. 132 5

Mitochondrial myopathies are morphologically characterized by ragged-red fibres (RRF). Serial cross-section revealed that the ragged-red appearance was only focal. This is in agreement with a partial cytochrome c oxidase (COX) deficiency in chronic progressive external ophthalmoplegia (CPEO). Since most of these patients show deletions of the mitochondrial genome single fibre analyses were performed determining COX and succinate dehydrogenase (SDH) in serial muscle sections from two patients with CPEO. High SDH activity was demonstrated in RRF; in contrast COX activity was lower in RRF in a patient, possibly representing a focal assembly of mitochondria with deletions in their genomes. The variation of enzyme activities along the muscle fibre was especially high in RRF. This study presents the first quantitative evidence that enzyme activities vary considerably along fibres in muscle from patients with a mitochondrial myopathy.
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PMID:Enzyme activity analyses along ragged-red and normal single muscle fibres. 133 Sep 95

The effect of chronic left ventricular pressure overload on the activities of mitochondrial respiratory chain enzymes was investigated in myocardial biopsies from the left ventricular apex of 13 patients undergoing aortic valve replacement for aortic valve stenosis. Transvalvular pressure gradients measured by left-sided heart catheterization ranged from 52 to 100 mmHg. The specific activity of mitochondrial respiratory chain enzyme complexes I+III (antimycin A sensitive NADH cytochrome c oxidoreductase) and the myocardial concentrations of coenzyme Q10 (CoQ10) increased significantly (P < 0.05) with increasing aortic valve pressure gradient. In contrast, the specific activities of complex IV (cytochrome c oxidase), succinate dehydrogenase, and citrate synthase, a mitochondrial matrix enzyme, showed no significant correlation with the pressure gradient. Since CoQ10 is the rate-limiting compound of the activity of complexes I+III but not of cytochrome c oxidase, succinate dehydrogenase, or citrate synthase, these data suggest that the increase in the activity of complexes I+III is due to the increase in CoQ10 content.
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PMID:Positive correlation between aortic valve pressure gradient and mitochondrial respiratory chain capacity in hypertrophied human left ventricle. 145 Jun 14

Vascular involvement in biopsied muscle specimens from 11 patients with chronic progressive external ophthalmoplegia (CPEO) with ragged-red fibers (RRF) was studied. Almost none of 69 intramuscular arteries examined were strongly stained with succinate dehydrogenase (SDH) except one patient who had 2 SSV (strongly SDH-reactive blood vessels) in his muscle biopsy. Although RRF and focal cytochrome c oxidase (CCO) deficiency in muscle fibers were the common histochemical changes in muscle biopsy specimens from CPEO patients, all mitochondria in both endothelial and smooth muscle cells of the arteries had normal morphology except for the two SSV and all mitochondria in the blood vessels had normal CCO activity by electron cytochemistry. The findings obtained from the present study were quite different from those in mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS), and myoclonus epilepsy associated with ragged-red fibers (MERRF) in which the striking vascular involvement with SSV is the most common and major abnormality in muscle biopsy specimens. To study vascular involvement in mitochondrial encephalomyopathies is the one of very important clues to understand the pathophysiology of phenotypic expressions in mitochondrial encephalomyopathies.
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PMID:[Vascular pathology in chronic progressive external ophthalmoplegia with ragged-red fibers]. 161 73

The etiology of idiopathic dilated cardiomyopathy (DCM) is yet unknown; this study aimed at further differentiation of the disease by means of enzyme histochemistry. Endomyocardial biopsies from the left ventricle of 40 DCM patients and 5 control specimens had enzymes examined histochemically and semiquantitatively and analyzed according to staining intensities of nicotinamide adenine dinucleotide tetrazolium reductase (NADH-TR), succinate dehydrogenase, cytochrome c oxidase, lactate dehydrogenase and acid phosphatase (aPh). In DCM, the NADH-TR activity was elevated as compared to controls, indicating impaired mitochondrial oxidative phosphorylation. However, a concrete relation of enzyme histochemical intensity to anamnestic, hemodynamic or histomorphometric data could not be determined, except for the fact that the intensity of the lysosomal enzyme aPh was elevated in DCM patients with a relatively high left ventricular ejection fraction. The results demonstrate an interindependence of structural, hemodynamic and historical parameters as well as enzyme concentrations in DCM. Thus, a pathological change in the enzyme concentrations tested here cannot be responsible for the functional myocardial impairment in DCM.
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PMID:Enzyme histochemistry of endomyocardial biopsies in idiopathic dilated cardiomyopathy. 165 Nov 62

A 5-month-old boy died of progressive heart failure that started at the age of 3 months. Autopsy revealed a mitochondrial cardiomyopathy and a mitochondrial myopathy of the limb muscle and diaphragm. Cytochemically random defects of cytochrome c oxidase were visualized by light and electron microscopy in the diaphragm and especially the heart muscle, the limb muscle showing a diffuse attenuation whereas the liver and kidneys reacted normally. The activities of NADH-dehydrogenase (complex I) and cytochrome c oxidase (complex IV) were severely diminished (20% residual activity of controls) in the skeletal and heart muscle. In the heart, succinate cytochrome c reductase (complex II/III) was additionally decreased to the same degree. Loss of cytochrome c oxidase activity was based on a reduction of both mitochondrial and nuclear derived subunits in the heart and diaphragm as revealed by immunohistochemical analysis, whereas the limb muscle showed a normal immunoreactive protein content. The results illustrate heterogeneous tissue expression of respiratory chain enzyme defects and demonstrate that a cardiomyopathy may be the leading presentation of a mitochondrial disorder in early infancy.
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PMID:Fatal infantile mitochondrial cardiomyopathy and myopathy with heterogeneous tissue expression of combined respiratory chain deficiencies. 165 34

A histochemical study of cytochrome c oxidase (CCO) was performed in the muscles from eight patients with full-blown zidovudine myopathy. All patients had ragged-red fibres (total cumulative count: 160) and myofilamentous changes, that predominated in type 1 fibres and included diffuse or punch-out myofibrillar loss (75 affected fibres) and constant cytoplasmic body formation (106 affected fibres). Inflammatory infiltrates were present in four out of eight patients. A partial CCO deficiency (22-47% of fibres; both types 1 and 2 affected) was detected in all cases, and contrasted with the normal or increased succinate dehydrogenase activity observed in most fibres. Among CCO-deficient fibres, 71% were normal on trichrome, but all ragged-red fibres were CCO-negative. Myofilamentous changes were restricted to CCO-deficient fibres. The present study strongly supports the idea that mitochondrial toxicity is the specific mechanism of zidovudine myopathy.
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PMID:Partial cytochrome c oxidase deficiency and cytoplasmic bodies in patients with zidovudine myopathy. 166 20


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