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Biomedical subjects

D Ivanov

Publications and source records attributed to D Ivanov.

54 records · Page 3Linked to original sources
PubMed1985

On some presynaptic effects of an aminotetraline derivative.

The article studies the effect of a newly-synthesized aminotetraline derivative with code 1b on some presynaptic mechanisms of nerve transmission. Compound 1b (1 X 10(-9) M) increases the contractions of electrically stimulated isolated rat anococcygeal muscle: on the background of cocaine (1 X 10(-7) M), the contractile response after 1b is potentiated, whereas after phentolamine (1 X 10(-9) M) compound 1b does not increase the contraction of the muscle. Compound 1b in concentration from 1 X 10(-8) M to 1 X 10(-7) M manifests a concentration-dependent potentiating effect (EC50-3.95 X 10(-8) M) on the contractile response of electrically stimulated isolated rat vas deferens. The alpha-adrenergic blocker yohimbin (1 X 10(-7) M) and compound 1b (1 X 10(-6) M) increase the contractions of electrically stimulated mouse vas deferens. The potentiating effect of 1b is eliminated by clonodone (1 X 10(-19) M) and haloperidol (1 X 10(-5) M). On electrically stimulated guinea-pig ileum 1b (2 X 10(-6) M) and morphine (1 X 10(-6) M) inhibit the contractions of the isolated organ, while their combined administration potentiates the inhibitory effect of morphine. Both the combined and the independent effects of 1b and morphine are eliminated by naloxone (1 X 10(-6) M) and 4-aminopyridine (1 X 10(-7) M). Both compound 1b (2 X 10(-6) M) and morphine (1 X 10(-6) M) manifest potentiated inhibitory effect on the contractile response of guinea-pig ileum, administered on the background of dopamine (1 X 10(-5) M) and haloperidol (1 X 10(-6) M).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

On some presynaptic effects of meramyzole (analgine-pharmachim).

The effect of Analgine in different concentrations on the contractions of electrically stimulated isolated guinea-pig ileum and mouse vas deferens is studied and compared with the effect of morphine on the same isolated organs. Analgine causes morphine-like but weaker concentration-dependent inhibitory effect (IC50 = 5.75 X 10(-6) M) on guinea-pig ileum, which is completely eliminated by naloxon and 4-aminopyridine. Upon simultaneous administration of morphine analgine, potentiation of the effect of morphine is observed, which is also eliminated by naloxon and 4-aminopyridine. Analgine has a weaker inhibitory effect (IC50 = 1 X 10(-4) M) on the contractions of mouse vas deferens, compared with its effect on the ileum. The same is also valid for the independent and combined with analgine effect of morphine, completely eliminated only by 4-aminopyridine, but not by naloxon. In cases of reduced Na+-concentration in the medium, the effect of analgine on the contractions of the ileum is weaker (IC25 = 4.43 X 10(-5) M), while that of morphine is stronger compared with normal conditions. Increased Ca++-concentration is parallelled by a weaker effect of analgine (IC25 = 4.76 X 10(-5) M), unlike the effect of morphine which is potentiated. It is possible to assume some interaction of analgine with a definite type of presynaptic opiate receptors, similar or identical to these receptors which are responsible for the peripheral effects of the narcotic analgesics.

Aminopyrine↗
PubMed1977

[Innervation of the m. sphincter pylori in cats].

The ultrastructure of neuro-muscular relations in m. sphincter pylori of a cat was examined by fixation with CsO4 using imersion and staining of a sample of tissue with uranyl acetate during delydration. There were regular, dense and parallel muscular cells with intersticial spaces in the range of 250 A. Structures with various round and oval forms fitted closely to the smooth muscle cells. They had homogeneous amorphous structure and small electronic density. Nervous bundles with variable size were located in the intersticial spaces. Isolated single nervous fibres were encountered at some sites. Axonic profiles were located from the plasmatic membrane of the muscular cells at a distance of least 430 A. There were contacts with structure similar to the synapses among isolated nervous profiles. There were also nervous profile which contained large (around 1500 A) granular vesicules. The author discuses the type of inervation of m. sphincter pylori as well as the vesicular content of axons.in view of the eventual functional significance.

Animals↗
PubMedDate not supplied

Synthesis, toxicological, pharmacological, and bronchodilating activity in vitro of some xanthineacetic acid derivatives.

The possibility of the preparation of some ester derivatives of dimethylxanthines from 1-theobromine- and 7-theophylline acetic acids and 7-(2-hydroxyethyl)-theophylline by DCC/DMAP-mediated esterification under mild conditions was studied. The structures of the compounds synthesized and by products isolated were demonstrated by microanalyses, UV-, IR-, and 1H NMR data. Acute toxicity assessment of the compounds on mice showed that compounds 4, 5, 6, and 7 are less toxic than aminophylline. A pharmacological study of the in vitro broncholytic effect (IC50 and pD2 values) of the derivatives and aminophylline showed that the new compound 4 (1,2,3,6-tetrahydro-1,3-dimethyl-2,6-dioxo-7H-purine-7-acetic acid 2-(1,2,3,6-tetrahydro-1,3-dimethyl-2,6-dioxo-7H-purin-7-yl)ethyl ester) has a strong bronchodilating effect on serotonine- and acetylcholine-induced spasm in guinea pig trachea. The same compound does not influence barbiturate-induced hypnosis and locomotor activity, unlike to the effect of the aminophylline, used as a reference substance.

Aminophylline↗
PubMedDate not supplied

Liposomes as immunological adjuvants for tetanus vaccine.

Finding a new immunological adjuvant has been a challenge all along. The aim of our study is to improve the level of antibodies against tetanus using liposomes as adjuvant. As can be seen from the results of our study, the liposomes are a competitive candidate in this respect.

Adjuvants, Immunologic↗
PubMedDate not supplied

Presence and significance of some antibodies/autoantibodies in patients with acute myocardial infarction and idiopathic dilated cardiomyopathy.

By using ELISA technique we determined the anti-myosin, actin, collagen type I and IV, cholesterol and phosphotyrosine proteins antibodies in sera from patients with acute myocardial infarction and idiopathic dilated cardiomyopathy. In idiopathic dilated cardiomyopathy we found a significant increase in five out of six types of antibodies tested. The patients with acute myocardial infarction reveal high levels of anti-myosin antibodies only. Our results suggest that some of the autoantibodies studied by us have a prognostic value and could be involved in maintaining cardiac dysfunctions.

Actins↗