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Biomedical subjects

T Ivanov

Publications and source records attributed to T Ivanov.

16 recordsLinked to original sources
PubMed2005

[CS by request--a reasonable alternative?].

The doctor-patient relation has been changing as a whole together with the evolution of society. The right of choice should play a main role in female public health as it represents a fundamental social and constitutional law. The growing rate of caesarean sections in Stara Zagora, Bulgaria and in the world are analyzed and the organizational factors having an impact on it are shown. On-line polls among doctors and patients were used. A conclusion was drawn that it is better to have the indication "caesarean section by patient's request" rather than performing abdominal deliveries under fabricated indications.

Bulgaria↗
PubMed2003

Schematic illustration of some of the mechanisms for maintenance of homeostasis in organism.

The aim of the present paper is to illustrate schematically by a non-equal arm lever system the mechanisms that maintain the homeostasis of reactive oxygen species, glucose, mean arterial pressure and electrolytes. All regulating factors that increase the values of each physiological parameter are placed on the same arm of the lever system. The regulating factors that decrease this value are placed on the other arm of the lever. In this way the two types of factors interact with one another and maintain the lever system in a dynamic equilibrium, i.e., contribute to keeping the homeostasis. Illustrating the maintenance of homeostasis by a non-equal arm lever system gives the opportunity to express the quickness, flexibility, stability and effectiveness of physiological regulations.

Animals↗
PubMed1996

Computer design and syntheses of antiulcer compounds. 1st communication: N-[3-[3-(1-piperidinomethyl)phenoxy]propyl]amines and benzamides.

Aiming to develop new antiulcer agents, a quantitative structure-activity relationship (QSAR) study on in vitro (pA2) and in vivo histamine H2-receptor antagonistic activity of a series of N-[3-[3-(1-piperidinomethyl)phenoxy]propyl]amines was carried out using the OASIS computer system. The results showed that pA2 increases with the decrease (increase) of electron donor (acceptor) properties of molecules, particularly at the NH-reaction site. The finding is consistent with the assumption for an increase of histamine H2-receptor activity of the antagonists with their ability to form H-bonds with the receptor through NH groups. The correlations with hydrophobicity and related topological indices are consistent with the hypothesis that logP should indirectly reflect receptor interactions. In addition a series of N-[3-[3-(1-piperidinomethyl)phenoxy]propyl]benzamides are synthesized. The theoretically predicted in vitro activities of these compounds were found to be in accordance with in vivo tests (percent of inhibition of gastric juice and acid output [mEq/H+/3 h]).

Animals↗
PubMed1995

Comparative analysis of singer's high formant in different type of singing voices.

The presence of singer's high formant (SHF) in singers of different musical styles was investigated. The voices of 10 opera, 8 folk, 4 pop singers and 53 (non-singing) controls were recorded. The vowel 'a' was sung in three different registers. The percent of energy in the range of SHF and the stability of the pitch period generation were evaluated. The signals of all the singers are characterized by very high stability of the pitch period generation (> 99%), but their formant structures differ considerably. Energy concentration in the range of SHF is 23, 16, 7 and < 4% for opera, folk and pop singers and the controls, respectively.

Humans↗
PubMed1993

[Hygienic research on new soap preparations for intensive laundry use].

The purpose of the study is to establish hygienic properties of the new preparations for intensive washing and their effect on the skin of man. Examinations are performed on 5 new washing preparations from firm "Verila": "Linda" (from the producer and from the trade network from the country--Ruse, Blagoevgrad, Stara Zagora, Pleven, Cherven Bryag, Plovdiv and Dobrich), recipe No 1, 2, 3 and 4. Sanitary and chemical examinations are carried out: organoleptic indices, nonionogenic surface active substances, total content of surface active substances, content of carbamide, sodium carbonate, ammonium nitrate, formaldehyde and free alkali. Investigations are made on 125 volunteers for skin irritative and allergenic effect, with epicutaneous test before and after 30-day washing--respectively with 0.5% and 2% and with 5% and 20% of the washing preparations. The results point out the absence of ammonium nitrate and formaldehyde and compliance with the content of the composition of the declared expenditure norms (except of "Linda" from the trade network of the country). There are no reactions of skin irritation and allergy in neither of the subjects with all washing preparations. Recommendations are given to the producer for observing the technological discipline and requirements to the packings.

Bulgaria↗
PubMed1991

PC based system for analysis of the voice of patients with laryngeal disease.

A low cost microcomputer system for analysis of the voice of patients with laryngeal diseases is proposed. The system realizes an evaluation of the following speech parameters affected by laryngeal disease: voice degree of hoarseness; pitch period (T0); pitch period perturbations; degree of subharmonic components; and number of the stops in T0 generation during sustained vowel phonation. Other nonacoustic parameters concerning the patient's status are input into the computer using the keyboard. The hardware consists of a microphone and an ADC-board (plugged into the PC) allowing the PC to be used as a system for pathological voice analysis. Preliminary experimental research has shown the effectiveness of the system.

Diagnosis, Computer-Assisted↗
PubMed1990

[Synthesis, stereochemistry and anticonvulsant action of 4-phenyltetrahydroisoquinolines].

The racemic and optically active 4'- and 8-substituted tetrahydroisoquinolines 2-5 have been synthesized and their effect on the water-immersion stress ulcer in rats has been studied. All compounds prevent the formation of stress ulcer, the strongest effect being exhibited by compound 4 and its dextrarotatory isomer (R1 = Cl, R2 = NHCOOC2H5). The antiulcer activity of 4 is 30 to 50 times higher than that of the H2 receptor antagonists Cimetidin and Ranitidin used for comparison. The absolute configuration of the optically active compounds 2, 3 and 4 has been determined by means of chemical correlation. The antiulcer activity of 4 is characterized by enantioselectivity, S-(+)-4 is three times as active than R-(-)-4.

Animals↗