Effect of quercetin on daunorubicin-induced heart mitochondria changes in rats.

Cancer therapy with daunorubicin is limited by its cardiotoxicity. It has been suggested that daunorubicin-induced free radical generation can be involved. The precise molecular mechanism of daunorubicin-induced cardiotoxicity is still not well understood but it is believed that mitochondria play an important role in this process. It has been reported that flavonoids with antioxidant properties may prevent anthracycline-induced cardiotoxicity. In this work, we investigated the effects of daunorubicin and quercetin on mitochondrial enzyme activities such as ATPase, glutathione peroxidase (GPx) and glutathione reductase (GR). Moreover, we also studied the changes of outer mitochondrial membrane using synchronous fluorescence spectra. The activity of ATPase and GR were significantly increased after daunorubicin application. Pretreatment with quercetin significantly alleviated this increase. On the other hand, GPx activity was significantly decreased and quercetin prevented this decrease. Treatment with quercetin alone had no significant effect on the enzyme activity studied. Quercetin also completely prevented daunorubicin-induced changes in fluorescence of the outer mitochondrial membrane. In conclusion, our data indicate that quercetin may be useful in mitigating daunorubicin-induced cardiotoxicity.

[Fe2+-induced oxidative processes in the liver mitochondria of rats]. / Oxidacné procesy mitochondrií pecene potkana indukované Fe2+.

The study investigated the prooxidative in vitro effect of various Fe(2+)-EDTA concentrations on biochemical parameters of the energetic metabolism of rat liver mitochondria. Fe(2+)-EDTA was added in concentrations 150, 300 and 400 mmol/mg of mitochondrial protein. The study included the investigation of consumption of oxygen in state 4 (without ADP addition) and in state 3 (with ADP addition), and the activities of ATP-ase, superoxide dismutase (SOD) and glutathione reductase. The mitochondrial outer membrane dynamics were simultaneously monitored by the method of synchronous fluorescence fingerprint. When compared with the control group, the results imply that in state 4, the addition of 150 mmol of Fe2+/mg of mitochondrial protein caused an insignificant increase in respiration to 104%, whereas in state 3, the oxygen consumption was insignificantly inhibited to 82%. The activity of ATPase was insignificantly raised to 105%, whereas the superoxide dismutase activity has decreased significantly to 77%. The activity of glutathione reductase increased significantly to 124%. The addition of 300 mmol of Fe2+/mg of mitochondrial protein has caused a significant inhibition of oxygen consumption to 67% in state 4 and to 31% in state 3. The activity of ATPase showed an insignificant elevation to 104%. The activity of superoxide dismutase was significantly reduced to 52% and that of glutathione reductase dropped to 72%. The addition of 400 Fe2+/mg of mitochondrial protein strongly diminished the oxygen consumption to 36% in state 4, and similarly to 37% in state 3. The activity of ATP-ase was significantly decreased to 39%, the superoxide dismutase activity diminished to 17% and glutathione reductase activity dropped to 37%. The monitoring of the mitochondrial outer membrane by the analysis of synchronous fluorescence fingerprint showed that the membrane is involved in these processes. (Fig. 5, Ref. 12.)

[Problems and perspectives of wider use of saliva for diagnostic purposes]. / Problémy a perspektívy sirsieho vyuzitia slín na diagnostické úcely.

Saliva of individual salivary glands differs in appearance, density and particularly in the chemical composition. Generally, the composition of saliva is affected by the composition of blood plasma, salivary flow rate, hormonal activity, drug administration, smoking and other physiological and pathophysiological states of the organism. In spite of these facts, many of the components are permanently present in saliva (e.g. peptides, enzymes, hormones...) only their concentrations vary. In some special cases unusual constituents can be detected in the saliva as legal and illegal drugs, antibodies (HIV), and abnormal bacteria or viruses. When there is good correlation between the levels of constituents in saliva and blood plasma then the determination of the constituent level in saliva can be used for diagnostic and/or monitoring purposes. But the main advantage of saliva analysis resides in stress-free and harmless collection of saliva in comparison with blood withdrawing. However, the use of saliva for diagnostic purposes is still at its beginning. So far, only few such applications are known, but optimists believe that the saliva analysis has a very prospective chance to substitute or alternate the biochemical analysis of blood plasma due to the mentioned advantage and to attribute more information on the processes in the human body. (Fig. 1, Ref. 16.)

[Use of methacrylate for internal fixation of fractures in small animals]. / Vyuzitie metakrylátu k internej fixácii zlomenín pri malých zvieratách.

An experiment was conducted to verify the possibility to use the self-polymerizing metacrylate resin DURACRYL EXTRA, commonly used in dental prosthetics, for simple fixing of fractures in small animals. The metacrylate was placed in a very small distance from the bone and the generally available surgical materials were used to connect it with the bone fragments (Kirschner's wires and surgical wire). Tree types of diaphysial fractions of femur and humerus were evaluated in a group of rabbits, dogs and sheep. The histological study of the reaction of the adjacent soft and hard tissues to metacrylate in the stage of healing of fracture is documented by the normal course of the reparative processes with no signs of more serious non-adequate reaction. The method of using the resin is generally simple, inexpesive and has low requirements for the use of instruments. This promises broad use in practice in the treatment of other kinds of fractures, mainly in those cases where there is a lack of special equipment for the surgery of bones.

Structure of N-terminal cyanogen bromide fragment of human plasma albumin.

The complete amino acid sequence of 87 residues of cyanogen bromide fragment CB1 (Asp), the N-terminal fragment of human plasma albumine molecule, has been established. The sequence was determined from the characterization of all tryptic peptides and of chymotryptic arginine-containing peptides in the fragment digested. Overlaps were obtained by tryptic and chymotryptic cleavage of the maleylated S-sulfo derivative of fragment CB1(Asp). Residue 34 is the only cysteine residue in the albumin molecule and it was determined in the form of S-carboxymethyl-cysteine. Edman and dansyl-Edman degradation were used for the sequential analysis.