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Biomedical subjects

K Tóth

Publications and source records attributed to K Tóth.

At least 127 records · Page 7Linked to original sources
PubMed1987

Promising reduction of ventricular fibrillation in experimentally induced heart infarction by antioxidant therapy.

Studies were undertaken using a synthetic free radical scavenger (MTDQ-DA) on regional ischaemic dog hearts; it was found that the rate of malignant ventricular arrhythmias and fibrillation after coronary ligature unexpectedly decreased. According to experiments on 22 dogs, the intravenous MTDQ-DA therapy decreases the unfavourable ECG consequences of left anterior descending branch ligature: already 5 to 10 minutes after drug administration the ST segment elevation, the QT interval lengthening and the occurrence of ventricular extrasystoles and salvos are diminishing. The so-called epicardial ST map ameliorates rapidly. MTDQ-DA as a blocking agent of free radicals is able to prevent the irritative stimuli around and in the border zone of an infarct, has a vigorous anti-arrhythmogenous effect and greatly reduces the electric heterogeneity. These unexpected results may lead to a promising therapy for the acute heart infarction.

Animals↗
PubMed1987

Salt effects on bacteriophage T7-I.

The thermal denaturation as a measure of the structural stability of the nucleoprotein in bacteriophage T7 has been studied in dependence of the ionic environment. Optical density and circular dichroism melting curves measured at wavelengths characterizing either the DNA or protein conformational changes were compared to identify different steps of the denaturation and to follow the effect of the ions. Monovalent salts strengthen the helical structure of intraphage DNA logarithmically in the way as they do in the case of isolated double-stranded DNA. Mg2+ and Ca2+ at very low concentrations stabilize the DNA helicity. Higher divalent ion concentrations decrease the stability of the double helix because of the repulsive ionic interactions. The high structural sensitivity of DNA in the presence of Mg2+ and Ca2+ in this "in situ" environment can be related to the biological role of these ions.

Calcium↗
PubMed1987

Salt effects on the bacteriophage T7-II structure and activity changes.

Optically detected thermal stability and biological activity of phage T7 has been compared as the function of the ionic composition and strength of the buffers. The ionic strength range was studied between 20-140 mmol/1. In Tris buffer containing only monovalent ions the biological activity of the phages decreases abruptly below 50 mmol/1 ionic strength. Structural studies show a logarithmic dependence between the ionic strength and the intraphage DNA stability and no significant change in the thermal stability of the whole phage. Mg2+ and Ca2+ ions at low concentration (1 mmol/1) given into a Tris buffer of 20 mmol/1 original ionic strength highly stabilize the biological activity, which stabilization is also to be seen in the intraphage DNA and also in the whole phage thermal denaturation process.

Buffers↗
PubMed1986

Detection and localization of ventricular preexcitation in Wolff-Parkinson-White syndrome (comparative study with body surface mapping).

21 patients with Wolff-Parkinson-White (WPW) syndrome were investigated through radionuclide imaging and body surface mapping. Ventricular preexcitation was localized by display of identical phase ventricular regions (phase display). In 79% of the cases radioisotope and body surface mapping methods have identical results for the site of preexcitation. In two patients of the control group (10 patients with Lown-Ganong-Levine (LGL) syndrome), false positive outside-of septum ventricular preexcitation was detected, i.e. an 80% specificity. It is concluded that phase display might be a suitable method in the diagnosis of WPW syndrome. The sensitivity of this method can be improved using several views.

Adult↗