RESUMO
Acidic and alkaline RNase activity from healthy humans and gastric cancer patients has been studied. A decrease in daily saliva production and an increase in RNase activity was detected saliva of cancer patients. This suggests the existence of RNase inhibitors in healthy humans. This supposition is further confirmed by comparative analysis of total, joint fractional and reconstituted RNase activity. A considerable increase in acidic RNase inhibitors and disappearance of alkaline RNase inhibitor was observed in cancer patients. The specificity, mechanisms and clinical significance of this phenomena has been discussed.
Assuntos
Ribonucleases/análise , Saliva/enzimologia , Neoplasias Gástricas/enzimologia , Ritmo Circadiano , Humanos , Concentração de Íons de Hidrogênio , Masculino , Pessoa de Meia-Idade , Valores de Referência , Ribonucleases/antagonistas & inibidores , Saliva/análise , Proteínas e Peptídeos Salivares/análiseRESUMO
Heterogeneity of mitochondrial fractions in solutions of sucrose, sucrose and EDTA, mannitol and EDTA, and in Krebs-Ringer solutions with and without glucose was assayed by morphometry. Heterogeneity of mitochondria in varied solutions significantly differed from that in situ. Statistical analysis of mitochondria in isolated fractions and in situ as well as an analysis of the literary data allowed a conclusion that the mitochondrial system in the nerve cell is threadlike rather than discrete in shape. It has been established that heterogeneity of mitochondria in vitro depends on the conditions of tissue homogenization and isolation of the mitochondrial fraction.
Assuntos
Encéfalo/ultraestrutura , Animais , Fracionamento Celular/métodos , Microscopia Eletrônica , Mitocôndrias/ultraestrutura , Ratos , Frações SubcelularesRESUMO
Cell suspension of the rat brain was separated into fractions of neuronal and glial cells (FNC, FGC) during 7-10 minutes. The suspension was filtered in the column through a series of filters with 400-600, 200 (FNC), 132 and 100 (FGC) mu pores. The purity of the fractions obtained was analyzed by light microscopy. According to a single cell counting the purity of FNC and FGC contituted 60 and 90%, respectively. The respective figures were 97 and 90% as shown by cell weight comparison. The biochemical and morphological findings indicate a good viability of isolated cells. It has been established that of total rat brain protein (108 mg per 1 g crude tissue), the proteins of nerve cells account for about 30%. The mass ratio of neurons to glial cells is 2.5:1. This fact should be taken into consideration during studies on the functional interactions between neurons and glial cells.
Assuntos
Encéfalo/citologia , Separação Celular/métodos , Neuroglia/citologia , Neurônios/citologia , Animais , Filtração , RatosRESUMO
By changing the quantities of rat brain homogenate or mitochondria, adding succinic acid and ADP a situation was created in polarographic cell leading to the initiation of Lardy and Chance control upon respiration. It is concluded that this control is characteristic of in vitro conditions, but not only of functional properties of mitochondrial preparations. For studying oxidative phosphorylation the disappearance of nonorganic phosphate must be estimated.
Assuntos
Difosfato de Adenosina/farmacologia , Encéfalo/metabolismo , Mitocôndrias/metabolismo , Consumo de Oxigênio/efeitos dos fármacos , Animais , Técnicas In Vitro , RatosRESUMO
The clousness of membrane of rat brain mitochondria isolated in Krebs-Ringer's solution was broken by suspending the mitochondria in distilled water. Function characteristics of lyzed organells did not decrease but were somewhat higher than those of the organells suspended in Krebs-Ringer's solution. The results were discussed in relation to the question of the role of clousness of the mitochondrial membrane in the mechanism of oxidative phosphorylation.
Assuntos
Encéfalo/ultraestrutura , Mitocôndrias/fisiologia , Fosforilação Oxidativa , Animais , Encéfalo/metabolismo , Membranas , RatosRESUMO
Functional properties of rat brain mitochondria were different in Krebs-Ringer solution as compared to these in the media with mannit. Mitochondria in the presence of cytochrme c increased endogenous respiration essentially after the introduction of mannit into the polarographic cell. It is concluded that mannit metabolised by mitochondria as other non-cell compounds, must not be in the media of incubation of mitochondria, while studying the oxidative phosphorylation mechanism.
Assuntos
Encéfalo/ultraestrutura , Mitocôndrias/metabolismo , Fosforilação Oxidativa , Difosfato de Adenosina/metabolismo , Encéfalo/metabolismo , Técnicas In Vitro , Manitol/metabolismo , NAD/metabolismo , Consumo de Oxigênio , Succinatos/metabolismoAssuntos
Encéfalo/metabolismo , Fosforilação Oxidativa , Animais , Técnicas In Vitro , Consumo de Oxigênio , RatosRESUMO
Mitochondria of white rat brain increased the respiration on succinate in response to ADP addition; in the presence of after NADH the respiration remained unchanged or decreased ofter addition ADP. When organelles were suspended in water distilled in the concentration of 3 mg of protein/ml and kept at melting ice temperature for 24 hours the response of mitochondria to ADP was not changed. Stechiometric relation between the number of electron of the oxidized substrate and absorbed by oxygen depended on ADP during succinate oxidation and did not change on NADH. ADP phosphorylation is suggested to proceed on the stage of the substrate dehydrogenation, rather than on the cytochrome part of the respiratory chain.
Assuntos
Encéfalo/metabolismo , Mitocôndrias/metabolismo , Fosforilação Oxidativa , Difosfato de Adenosina , Animais , Técnicas In Vitro , NAD , Consumo de Oxigênio , Ratos , SuccinatosRESUMO
Activities of succinate dehydrogenase, succinate- and NAD-H-cytochrome c--reductases, and cytochrome c--oxidase was compared in 1 g tissue homogenate and homogenate fractions made from 1 g brain tissue using various solutions. Fractionation resulted in the increased activities of NADH- and succinate cytochrome reductases, and in the loss of succinate dehydrogenase activity, cytochrome oxidase was less influenced. These phenomena are regarded as signs of the interrelation between mitochondria and other constituents of brain cell within homogenates. Maximal quantity of mitochondria isolated from homogenates is no more than 20% of all the mitochondrial homogenates (according enzyme data). The electronogram of the brain mitochondrial preparation isolated in the Krebs--Ringer solution without glucose pointed out to a high homogeneity of mitochondria in the residue.
Assuntos
Encéfalo/ultraestrutura , Mitocôndrias , Animais , Encéfalo/enzimologia , Redutases do Citocromo/metabolismo , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Mitocôndrias/enzimologia , Ratos , Frações Subcelulares/ultraestrutura , Succinato Desidrogenase/metabolismoRESUMO
After introducing rat brain homogenate or mitochondria into polarographic cell without adding the substrate a quick shift of recording pen from the point of initial concentration of oxygen towards zero is observed. According to Kotova and coworkers (Biochemia, 38, 287, 1973) this shift is accompanied by a decrease of oxygen concentration (less than oxygen rapid consumption greater than). We established that the size of this shift was not proportional to the quantity of homogenate. Boiled homogenate of the rat brain, liver DNA solution, starch gel and casein glue caused less than oxygen rapid consumption greater than. It was proposed to locate the point of the initial oxygen concentration on the polragoramme in the position of the recording pen after the introduction of homogenate into the polragoraphic cell.