[Carbon nanotube-based biosensors for DNA structure characterization].

The possibility of DNA detection using electrodes modified with carbon nanotubes (CNTs) was studied. CNTs facilitate the electrochemical oxidation of DNA guanine nucleotide, which allows direct detection of DNA on a modified electrode. Electrochemical properties of DNA depend on its secondary structure and molecular weight. Denaturation of native DNA improves the adsorption of biopolymer on CNTs and results in an increase in DNA oxidation current on the modified electrode. A similar effect is observed after ultrasonic shearing of DNA or its treatment with Fenton's reagent due to the fragmentation of biopolymer. Our results demonstrate the feasibility of biosensors based on CNT-modified electrodes for the direct detection and characterization of DNA and DNA damaging factors.

[Characteristics of arrhythmia and late ventricular potentials in patients with cardiological syndrome X]. / Kharakteristika narushenii serdechnogo ritma i pozdnie potentsialy zheludochkov u bol'nykh s kardiologicheskim sindromom X.

AIM: A comparative study of late ventricular potentials (LVP) in patients with cardiological syndrome X (SX) and stenotic atherosclerosis of coronary arteries (ACA) as well as their relations with arrhythmia, cardiac contractility, lipid metabolism and morphological characteristics of the myocardium. MATERIAL AND METHODS: The examination of 52 SX and 77 ACA patients as well as 17 healthy subjects included coronaroventriculography, bicycle exercise, 24-h ECG monitoring, echocardiography, signal-averaged high-resolution (SAHR) ECG, investigation of blood lipoproteins. Endomyocardial biopsy was made in 5 ACA and 5 SX patients. RESULTS: No differences were registered between SX and ACA patients by frequency and severity of arrhythmic episodes, percentage of patients with registered LVP, quantitative parameters of SAHR ECG. Frequency of high-gradation ventricular arrhythmia episodes was significantly higher in SX and ACA patients with LVP than such patients free of LVP. SX patients had correlation between parameters of SAHR ECG, myocardial contractility and lipid metabolism. Foci of diffuse cardiosclerosis are most probable anatomic substrate of LVP. CONCLUSION: The risk of prognostically unfavourable high-gradation ventricular arrhythmia episodes in SX and ACA patients is the same. LVP may predict severe ventricular arrhythmia episodes both in SX and ACA patients.

[The iodine allowance and the prevalence of goiter among the children in organized collectives in the city of Kemerovo]. / Obespechennost' ioda i rasprostranennost' zoba sredi detei organizovannykh kollektivov g. Kemerovo.

Nutritional value of diets given to children attending kindergartens and schools in Kemerovo according to specified menu (proteins, vitamins, minerals) has been studied. The unbalance in diet ration leading to development of iodine deficiency in children of these institutions is responsible for high incidence of goiter. The level of iodine deficiency is 34.0% in kindergartens and 78.2% in boarding schools. High occurrence of goiter in children's institutions should be considered in planning antigoiter preventive measures.

[Urea and amino acid transport by an isolated human placenta]. / Perenos mocheviny i aminokislot izolirovannoi platsentoi cheloveka

A method of bilateral perfusion of the isolated human placenta was used to study the urea transport from the fetal placental stream into the maternal one, and of amino acid transport in the opposite direction. Experiments demonstrated that the method provided a sufficiently full perfusion of the intervillous space and offered possibilities for studying the placental transport. With equal amino nitrogen concentration in both circulations, its content in the fetal stream increased during the experiment. This elevation was more expressed when amino acid was added to the maternal circulation. The idea of amino acid "secretion" by the trophoblast cell elements into the fetal circulation was confirmed by the above experiments.