Biochemistry and experimental biology最新文献

Unlabelled: Monoamine oxidase (MAO) and aspartate aminotransferase activities in cellular fractions of thyroid gland in rats after hypophysectomy and TSH treatment were investigated. MAO and aspartate aminotransferase activities in thyroid mitochondria were decreased after hypophysectomy and significantly increased after daily injection of TSH during five days to hypophysectomized rats. In microsomes after hypophysectomy a similar decrease of MAO activity was found but TSH was without effect on this activity.

In conclusion: it is evident that MAO and aspartate aminotransferase in thyroid mitochondria the enzymes which could be a source for hydrogen peroxide to catalyze thyroid hormone synthesis are under the regulatory influence of TSH.

The effect of Phallolysin on cellular growth, macromolecular biosyntheses and cellular membrane structure was analysed using cells from the EUE line. Concentrations of the toxin that do not affect cellular growth, as determined by plating efficiency, have no effect on RNA or protein synthesis, but stimulate DNA synthesis. The doses of Phallolysin that inhibit cell survival do not affect macromolecular biosyntheses, but greatly increase the percentage of cells stainable with Trypan blue after 1 hour of incubation. At the same dose of the toxin the cells, analysed by electron microscopy, show increased vacuolization indicating an alteration of the membrane apparatus.

Fifty biopsies of finger-tips, from diabetic patients were examined. We wish to emphasize, of damage in the blocking devices and in the preglomic arterioles as opposed to the limited modifications produced in the small dermic and hypodermic arteries. The glomera are almost constantly affected in their various components: in particular, the fusion of the glomic capsule with the intra- and extraglomic connective should be noted, as well as the presence of accumulated P.A.S. positive material among the mioepithelioid cells in the intermediate segment. The capillaries are frequently affected by hyperplasia of the intimal endothelium, sometimes with subocclusive phenomena, while the basal membrane is thickened and P.A.S. positive more often in extraglomic than in intraglomic capillaries.

The activity of some of the clinically important enzymes was investigated in leukemic sera at 37 degrees, using the Beckman Enzyme Activity Analyzer were found to be slightly elevated in some untreated cases of leukemia (1.), while ALP was found to be frequently elevated. Untreated patients with l. had normal or below normal SCPK activity. The most characteristic and significant rise in activity, was found to be associated with SLDH and SHBDH in most cases of acute l. (86%) and in CML, while any elevation observed in CLL, was very slight. The general kinetic parameters of SLDH and SHBDH, were investigated at 37 degrees in acute leukemic patients. These included optimum substrate concentrations (NADH, pyruvate, and 2-oxobutyrate), the rate of pyruvate and 2-oxobutyrate reduction, substrate-velocity relationship, Km (pyruvate), Km (NADH), Km (2-oxobutyrate) as well as the effect of temperature and pH on the kinetics of the reaction. These kinetic characteristics were found to be differently affected by the leukemic process.

This study reports the quantitative effect of the H1--and H2--receptor antagonists on dextran-induced anaphylactoid oedema in rats. The findings indicate that mepyramine, promethazine and chlorpromazine which are H1--receptor antagonists significantly inhibited this anaphylactoid oedema. While on the other hand burimamide an H2--receptor antagonist at doses below 500 micrograms/kg inhibit dextran-induced oedema but at higher doses enhances oedema formation in the test rats. E.D50 values obtained for mepyramine, chlorpromazine and promethazine are 5.01 mg/kg, 0.36 mg/kg, 1.78 mg/kg respectively. The dual effects of burimamide on dextran-induced oedema merits further investigation and confirmation with the aid of other H1--and/or H2--receptor systems. A modification of the plethysmometric method of Buttle et. al. (1957) is also described.

The effects of high cholesterol diets on ultrastructure morphologic alterations of rat liver have been investigated. It has been verified that these diets induce the biochemical and morphological damage, as well as death in a shorter time than alipidic or sole saturated lipid diets. Moreover it has been established that the anatomic irreversible damage appears at the last stage, just before death.

A group of diabetic patients was submitted to a capillaroscopic examination at the level of the peri-ungual vallum and to a fluoroangiographic examination of the retina, for the evaluation of possible correlations between vessel conditions in to various districts. The Authors remarked that the subjects affected by proliferative diabetic retinopathy presented a greater dilatation of the ansae at cutaneous level, with haemorrhagic extravasations in 70% of the cases. On the contrary, on the subjects with nonproliferative diabetic retinopathy numerous aneurysmal "buttons" were noted at cutaneous level, both apically and laterally along the vascular ansa.

The lethal irradiation with gamma-rays (LD 100/30) of adult mice at ambient temperature of 32.5 degrees C heavily alterates the pattern of LDH in liver. In close correspondence with the radioprotective effect of Solcoseryl on the survival rate of irradiated mice -- which amounts to 100% as compared with 40% survival of solely heat adapted animals -- Solcoseryl normalizes the LDH distribution both histochemically and biochemically. Since Solcoseryl alone generally enhances enzyme activity the normalization observed is obviously attributable to an intrinsically regulatory property of this natural compound.

Fibrinolytic activities on cases with chronic renal failure, 13 cases at pre and post introduction of hemodialysis and 40 cases at pre and post hemodialysis of maintenance hemodialysis with 38 normal controls were investigated. The plasminogen activator of untreated chronic renal failure was lower than controls, yet increased with the introduction of hemodialysis. On the other hand the antiplasmin was lowered with the introduction. In cases with maintenance hemodialysis, the plasminogen activator was lower than controls, but was elevated with hemodialysis. The level of antiactivator was higher in uremia of either pre or post hemodialysis than controls. The levels of alpha 2-macroglobulin and alpha 1-antitrypsin were reduced at prehemodialysis state comparing to controls, and yet, increased with hemodialysis, respectively. The low molecular weight antiplasmin and antiactivator, molecular weight below 30,000 were separated with Sephadex G-50 gel filtration of plasma. The low molecular weight fibrinolysis inhibitors of plasma with untreated uremia were elevated comparing to controls, but decreased with the hemodialysis. The removable fibrinolytic inhibitors were indicated, however, the ratio of the low molecular weight fibrinolytic inhibitors to the total fibrinolytic inhibitors were little.