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Biomedical subjects

M I Titov

Publications and source records attributed to M I Titov.

69 records · Page 4Linked to original sources
PubMedDate not supplied

[A structure-activity study of a catalytic antiidiotypic antibody to the human erythrocyte acetylcholinesterase].

The catalytic monoclonal antibody 9A8 (MA 9A8), antiidiotypic to the antibody AE-2 (MA AE2) produced to the active site of acetyl cholinesterase from human erythrocytes, was subjected to a structure-function study. The specific binding of MA 9A8 to MA AE2 (K 2.26 x 10(9) M-1) was shown by the method of surface plasmon resonance, and the functional activity of MA 9A8 was demonstrated. Unlike acetyl cholinesterase, this antibody specifically reacted with the irreversible phosphonate inhibitors of esterases. A peptide map of MA 9A8 was analyzed by MALDI mass spectrometry. The Ser99 residue of its heavy chain was shown to be within the active site of the catalytic antibody. A computer modeling of the MA 9A8 active site suggested the existence of a catalytic dyad formed by Ser99 and His35. A comparison of the tertiary structures of the MA 9A8 and the 17E8 monoclonal antibody, which also exhibited an esterase activity and was produced to the stable analogue of the reaction transition state, indicated a practically complete coincidence of the structures of their presumed active sites.

Acetylcholinesterase↗
PubMedDate not supplied

[Mitochondrial H+-ATPase: identification of subunits of the F0 subcomplex contacting with membrane lipids].

The subunits of the F0 membrane sector of bovine heart mitochondrial H(+)-ATPase that contact the lipids of the mitochondrial inner membrane were identified with the use of specially synthesized proteoliposomes that contained active mitochondrial H(+)-ATPase and a photoreactive lipid, which was 1-acyl-2-[12-(diazocyclopentadiene-2-carbonylamino)-[12-14C]dodecanoyl]-sn- glycero-3-phosphocholine, 1-acyl-2-[11-([125I]diazoiodocyclopentadiene-2-carbonyloxy)undecanoyl]-sn- glycero-3-phosphocholine, or 1-acyl-2-[12-(diazocyclopentadiene-2-carbonylamino)dodecanoyl]-sn-glycero- 3-phosphocholine, where acyl is a mixture of the residues of palmitic (70%) and stearic (30%) acids. An analysis of the cross-linked products obtained upon the UV-irradiation of these proteoliposomes indicated that subunits c and a of the F0 membrane sector contact the lipids. The cross-linked products were identified by SDS-PAGE and MALDI mass spectrometry.

Animals↗
PubMedDate not supplied

[Experimental approaches to treatment of prostatic adenoma with the luliberin analog surfagon].

Therapeutic efficacy of surfagon, an analog of LH-RH which was injected subcutaneously at a daily dose of 100 micrograms/kg for 30 days, was investigated in ACI male rats with induced prostatic adenoma. This drug was shown to be effective proceeding from a morphological study and measurement of the prostate. Measurement of blood testosterone levels by radioimmunoassay showed a decrease in this level in rats, treated with surfagon, i. e. a therapeutic effect of the drug in prostatic adenoma was accompanied by a decrease in the level of androgens.

Animals↗
PubMedDate not supplied

Copper (II) complexes as a laccase model in the catalytic removal of the phenylhydrazide protecting group under mild oxidative conditions.

Copper (II) complexes, with nitrogen-containing ligands (pyridine and imidazole), simulate perfectly the catalytic activity of laccase in the oxidative removal of the phenylhydrazide protecting group. Deblocking occurs under mild conditions, preventing the oxidation of labile amino acids. The effect of certain factors on the rate of deblocking and the degree of conversion were studied, and optimal conditions providing 100% yield of the deblocked products were chosen.

Amino Acid Sequence↗
PubMedDate not supplied

[Accumulation of ATP by plasma membrane preparations enriched by particles from hypophyseal cells under the effect of thyrotropin-releasing hormone].

Thyrotropin-releasing hormone (TRH, thyroliberin) is endogenous tripeptide, which is synthesized in hypothalamus and is responsible for multihormonal regulation of synthesis and secretion of hormones in the anterior lobe of the hypophysis. TRH is required as an obligatory factor stimulating the GH cell lines growing in cell culture. As indicated in previous studies activation of target cells (in response to effects of insulin, growth hormone, polypeptide factors of growing, mitogens, chemostimulators) followed by fast alterations in phosphorylation of membrane components which is realized via generation of "signal" ATP in plasmatic membranes. This type of ATP was synthesized within 1 min in the preparations of particles enriched with plasmatic membranes isolated from bovine hypophyses and washed in 0.25 M sucrose, if the particles were incubated in the mixture containing TRH 30-40 mg/ml, Tris-HCl buffer, rH 7.5, ADP-Na salt Mg2+, inorganic phosphate, NaF, under conditions of NADH oxidation in presence of cytochrome c and oxygen. Accumulation of TRH-stimulated ATP in plasmatic membranes was detected, after addition of the kinases inhibitor 5'-fluorosulfonyl benzyladenosine into the incubation mixture, in II large scale experiments. The rate of TRH-stimulated synthesis of ATP was dissimilar in various preparations of hypophyses and was equal to 0.21-11.6 nmol/min/mg of protein at 30 degrees Plasmatic membrane signal ATP appears to serve as a secondary "membrane messenger" for TRH during transfer of a signal and its acceleration from the TRH receptors along the cell surface to membrane effectors--kinases.

Adenosine Triphosphate↗
PubMedDate not supplied

[Comparative evaluation of the effect of kontrikal, 5-fluorouracil and the new Soviet peptide preparation dalargin on the course of experimental pancreonecrosis].

The experiments on 24 dogs with experimental hemorrhagic pancreonecrosis showed that contrykal and 5-fluorouracil insignificantly decrease the area of the damaged parenchyma, fail to cease progression of the pancreas destruction. The peptide drug dalargin in these conditions increased the antitryptic activity and normalized BAEE esterase activity. Dalargin abolished erythrostasis and microthromboses in the vessels of the microcirculation, restored the blood supply throughout the area of the exocrine parenchyma, limited necrotic foci and suspended the development of pancreonecrosis.

Animals↗
PubMedDate not supplied

[A new peptide activator of reparative tissue regeneration].

Synthetic analog of leucine enkephalin--hexapeptide dalargin was shown to stimulate healing of skin wounds in rats, dogs and mini-pigs at local and parenteral administration in doses of 0.1-100 micrograms/kg. Acceleration of proliferation with an increase of fibroblast mitoses, earlier and active growth of vascular elements, rapid maturation of granulation tissue and accelerated epithelialization were observed.

Animals↗