Studies on the subcellular localization of corticotrophin releasing factor (CRF) and vasopressin in the median eminence of the rat.
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Cytochrome oxidase (CO) activity on alkali-burned rabbit corneas was investigated histochemically to determine the metabolic change in inflamed corneas during wound healing. Cryostat sections of chemically burned and mechanically scraped corneas were stained for CO activity, which is regarded as an index of metabolic activity. Following chemical injury, positive CO activity was detected initially in the vascular endothelial cells of limbal blood vessels. Numerous active polymorphonuclear leukocytes (PMNs) and monocytes were found intravascularly and perivascularly. Fibroblasts that appeared at the wound site exhibited marked CO activity around the limbus. Over a period of 13 days, PMNs gradually invaded the central cornea, followed by fibroblasts of high metabolic activity. The areas of PMN infiltration were the same areas in which fibroblasts showed intense staining, suggesting that a PMN-derived mediator or secondary products might affect the activation of fibroblasts. Epithelial resurfacing was delayed in the chemically burned corneas, although reepithelialization was completed within two to three days in the scraped corneas. Limbal epithelial cells, which recently were suggested as the source of epithelial renewal, showed a remarkable increase of metabolic activity in response to chemical inflammatory stimulation, whereas those in the scraped model did not. This suggests that epithelial cell renewal at the limbus was accelerated in the presence of disturbed reepithelialization.
Caulobacter crescentus is an aerobic Gram negative bacterium found in bacterial biofilms. C. crescentus produces a sessile stalked cell during its life cycle that allows it to attach to surfaces. Due to the oxygen gradient found in the bacterial biofilm, we postulated that C. crescentus would localize the terminal cytochrome to the cell body that remains in the aerobic portion of the biofilm. The terminal electron acceptor in the electron transport system was determined using Kovac's oxidase test to be cytochrome c oxidase. We are able to use diaminobenzidine to locate the oxidase histochemically using transmission electron microscopy. Upon examination of sectioned bacteria, we determined that cytochrome c oxidase of C. crescentus is found only in the cell body.
AIM: To study the effects of nitroquine acetate (NA) on the ultrastructures and cytochrome-c oxidase (CCO) of exoerythrocytic forms (EEF) of Plasmodium yoelii. METHODS: Rats were inoculated with sporozoites directly into the liver. After 48 h rats were killed. Rat liver thin sections were incubated in histochemical reaction medium, then examined by transmission electron microscopy. NA (2 mg.kg-1) was fed to rats 3.5 h and 14 h before killing the rats. RESULTS: At 3.5 h, in the parasites there appeared swelling and proliferation of mitochondria, dilation of endoplasmic reticulum, and reduction of the electron density of parasites' nuclei. The structures of the parasites disintegrated to form many autophagocytes 14 h after exposure to NA. The reaction products of CCO still existed until 14 h after using NA. CONCLUSION: CCO was not the starting point of NA action. NA interferes with the structure and function of the cytoplasm and nucleus of malaria parasites and exerts its antimalarial effects in many aspects.
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Cytochrome oxidase and succinic dehydrogenase activities were studied in the mitochondria of rat thyroid cell during experimental malignization by means of the electron-cytochemical and morphometric methods. The activity of these enzymes in the mitochondria changed depending on the stage of malignization: at the early stages it approached the normal activity, and at the later stages (precancer)--it decreased and approached the mitochondrial activity of cancer cells. A sharp decrease in the activity of the enzymes under study in the morphologically changed mitochondria of cancer cells may characterize their qualitative changes.
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The studies of metabolism and morphology of the myocardium, and of ECG parameters in 72 patients with valvular pulmonary stenosis conducted with biopsy and autopsy material has demonstrated that while the workload on the right ventricle grows and the severity of the pathological process increases, the oxidative capacity of the myocardium also increase, the indices of its energy supply decrease, the degree of myocytes hypertrophy grows, and the number of mitochondria and the coefficient of their energy efficacy decrease. A correlation was established between the degree of these changes and the severity of electrocardiographic signs of hypertrophy and disorders in the repolarization process in the right ventricle.
1. The membrane-bound succinoxidase of Escherichia coli was fractionated with deoxycholate into three soluble components, viz. succinate dehydrogenase.cytochrome b1 complex, cytochrome oxidase complex, and a factor identified as a phospholipid-containing component. 2. The dehydrogenase and cytochrome oxidase complexes were partially purified by filtration on Amicon membranes, Sepharose 4B chromatography, and sucrose gradient centrifugation. 3. Reconstitution of membranous succinoxidase, which catalyzes the oxidation of succinate by molecular oxygen by an integrated CN(-)-sensitive pathway, was achieved by mixing the soluble succinate dehydrogenase.cytochrome b1 complex with the soluble cytochrome oxidase complex in the presence of deoxycholate and then removing the detergent by gel filtration on Sephadex G-75. The phospholipid-containing factor stimulated the formation of succinoxidase by about 100% over that observed with the two complexes. 4. Isopycnic sucrose gradient centrifugation of succinate dehydrogenase.cytochrome b1 complex, cytochrome oxidase, and the reconstituted succinoxidase gave buoyant densities (p value) as 1.167, 1.229, and 1.194, respectively. 5. Electron microscopic evidence is presented for the vesicular nature of the reconstituted succinoxidase.
Optimum conditions are developed for ultracytochemical detection of cytochrome oxidase in cardiomyocytes from the rat heart ventricles. Conditions mentioned above rest on using of o-dianisidine and double contrasting of microscopic sections by uranyl and lead acetates. Data from studies in heterogeneity of cytochrome oxidase activity as dependent on the structural-functional state (electronic density) of myocardium cells are presented.
Cytochemically demonstrated cytochrome oxidase activities in mitochondria of rat pulmonary alveolar epithelial cells were quantitatively compared. As the standardized procedures, lungs were fixed for 10 min at 4 degrees C with 2% pure glutaraldehyde, and incubated for different times at 37 degrees C in a medium containing 1.0 mg/ml 3,3'-diaminobenzidine-4HCl, 1 mg/ml cytochrome c, 0.1 mg/ml catalase, 7% sucrose, and 0.1 M phosphate buffer, pH 7.4. Electron micrographs were then obtained, and the densities of the reaction deposits in the mitochondrial intermembrane-intracristal space were measured in an image analyzer, and were plotted in terms of time in minutes. The initial velocity (maximal rate) of the activity expressed as deposit accumulation rate (% area/60 min) filling the mitochondrial intermembrane-intracristal space of Type I, Type II and Type III cells was 40, 130 and 9.3, respectively. These results indicated that mitochondria are varied in the intensity of cytochrome oxidase activity among 3 types of pulmonary alveolar epithelial cells, and that the image-analyzing measurement of the accumulation rate of reaction product may be useful for quantitative analysis of enzyme activity, in particular, in the cells which are difficult to isolate from complex tissues.
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In this paper, we have described mitochondrial cytochemistry (NADH oxidase, cytochrome c oxidase), in the light and electron microscopic studies of the experimental mitochondrial myopathies. DNP, oleate and crotoxin were employed to produce mitochondrial changes in the rat skeletal muscle. The DNP and oleic acid lesions showed strong NADH oxidase and cytochrome c oxidase activities in mitochondria--both at the light microscopic as well as at ultrastructural level. However, the crotoxin lesions showed marked reduction of both the enzyme activities in histochemistry and electron microscopy. Muscle necrosis was seen only in the crotoxin lesion. On the basis of these data, we propose that DNP and oleic acid treatment produced mitochondrial myopathies in which the mitochondrial structure was altered but they were enzymatically active, while the crotoxin treatment produced the structural and enzymatic alterations of the mitochondria.
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