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Biomedical subjects

A A Tsvetkov

Publications and source records attributed to A A Tsvetkov.

18 recordsLinked to original sources
PubMed2001

Observation of the transverse optical plasmon in SmLa0.8Sr0.2CuO4-delta.

We present microwave and infrared measurements on SmLa0.8Sr0.2CuO4-delta, which are direct evidence for the existence of a transverse optical plasma mode, observed as a peak in the c-axis optical conductivity. This mode appears as a consequence of the existence of two different intrinsic Josephson couplings between the CuO2 layers, one with a Sm2O2 block layer, and the other one with a (La,Sr)2O2-delta block layer. From the frequencies and the intensities of the collective modes we determine the value of the compressibility of the two dimensional electron fluid in the copper oxygen planes.

Journal Article↗
PubMed1991

[Catheter-balloon valvuloplasty in mitral valve stenosis (selection of the method of procedure, immediate results and the criteria of patient selection].

Catheter-balloon valvuloplasty (CBV) was carried out in 80 patients with rheumatic mitral stenosis, whose ages ranged from 22 to 68 years. Seventeen of these patients were operated on for mitral valve restenosis; I-II degree calcinosis of the mitral valve was revealed in 18 patients; seven women underwent surgery in the 24th-32nd week of pregnancy. After applying various methods (19 cases) the authors used in the last series of operations (61 cases) the Silin-Sukhov method using an original dilatation catheter with a balloon measuring in diameter up to 34 mm, which allowed pressure of up to 8 atm. to be produced during a working cycle no longer than 8 sec. As the result of CBV, the area of the mitral orifice was enlarged by no less than twice in all patients, the pressure gradient through the mitral valve and systolic pressure in the pulmonary artery reduced. The total number of complications which called for operative treatment was 3.75%. CBV is a still developing method, but already today it may be considered the method of choice in the treatment of uncomplicated forms of mitral stenosis, in I-II degree calcinosis, and when the risk of the traditional surgical intervention on the heart is increased.

Adult↗
PubMed1991

[Treatment of mitral valve stenosis in pregnant women by the method of balloon valvuloplasty].

Catheter-balloon mitral valvuloplasty was performed in 7 females with rheumatic mitral stenosis on the 19th-32nd week of pregnancy. Four patients were operated on with signs of cardiac insufficiency, two--in a state of pulmonary pre-edema. Edema of the lungs in one patient continued developing on the operating table. The results of the treatment were good in all cases. The area of the mitral orifice increased from 0.9-1.75 to 2.4-3.5 cm2. The pressure gradient between the left atrium and the left ventricle dropped from 25-40 to 2-8 mm Hg. This was attended by the disappearance of the diastolic murmur and the clinical manifestations of stasis in pulmonary circulation in all patients. The development of mitral regurgitation after the operation was not encountered in any of the patients. The period of roentgenoscopy lasted 17.5 min. on the average. Screens were used to protect the fetus from the direct effect of the X-rays. Pregnancy ended in delivery in 6 patients; spontaneous labor at term occurred in 4, cesarean section had to be performed in one patient with placenta previa; one woman gave birth to twins on the 36th week of pregnancy. All the babies were healthy. Catheter-balloon valvulotomy does not yield to closed mitral commissurotomy in efficacy. The fact that it is only mildly injurious and does not need general anesthesia make this intervention preferable for pregnant women suffering from mitral stenosis.

Adult↗
PubMed1977

[Determination of cardiac output by the method of tetrapolar chest rheography and evaluation of its metrological possibilities].

Tetrapolar chest rheography is an up-to-day, convenient and bloodless method of determining the cardiac stroke volume (CSV) and cardiac output (CO) in dynamic observations. The paper presents and analysis of the method and considers the possibilities and limits of its application in determining the stroke volume and cardiac output. Advantages of the Kubicek procedure as modified by the authors by comparison with other rheographic methods are shown, along with methodological procedures employed for dtermining the CSV and CO and a nomogram that significantly facilitates the calculation of the values under study is offered. Results of contrasting the cardiac ejection values in patients with congenital heart diseases and an increased pulmonary circulation as against those in patients with ischemic heart disease, obtained by means of tetrapolar chest rheography and direct Fick's method are cited. The possibility of applying tetrapolar chest rheography in assessing the effect operative treatment in patients with congenital cardiac defects and also when investigating compensatory reactions of the cardio-vascular system in patients with hypertensive disease in the course of the orthostatic and Valsalva tests is demonstrated.

Adult↗
PubMed1976

[Diagnosis of thrombosis of the left atrium in rheumatic heart defects, using the main components methods].

A new method of diagnosis of left atrial thrombosis was developed for rheumatic heart disease patients. The mathematic method of the main components was used that permits to detect the thrombosis of the left atrium in 94.3% of the cases. Fourteen most frequently encountered symptoms of this complication were singled out, the probability of the occurrence of these symptoms was calculated for the patients with rheumatic heart diseases and atrial fibrillation with and without thrombosis. A computer was employed to develop the method, while no computer is needed for the diagnosis itself. Symptoms from the list must be identified in the given patient, the digital values of the main components found in the table be summed up with that of the free member, with due regard of the sign, and the presence of the thrombus be determined on the basis of the presented chart.

Atrial Fibrillation↗
PubMedDate not supplied

[Local capillarotrophic insufficiency syndrome in patients with osteoarthrosis deformans (polarographic and thermographic data)].

The condition of microcirculation in the region of the joints was studied by means of polarography on oxygen with an oxygen load and thermography on the Soviet high resolution television set "Paduga" in 30 patients with primary deforming osteoarthrosis (PDOA) and 15 practically healthy persons. Different direction shifts in the levels of supply and consumption of oxygen in the periarticular tissues in patients with PDOA were determined, a considerable drop in oxygen supply to the regions of the affected joints being noted. It has been established that thermography is a method of choice for diagnosis of secondary synovitis and other inflammatory affections of the joints.

Adult↗