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Biomedical subjects

L A Nikitina

Publications and source records attributed to L A Nikitina.

At least 19 recordsLinked to original sources
PubMed2005

[Genetic factors of risk of ischemic heart disease development in patients with familial hypercholesterolemia].

UNLABELLED: Ischemic heart disease (IHD) develops in patients with familial hypercholesterolemia (FHC) 15-20 years earlier than in general population. However age of onset of the disease, its clinical manifestations are variable and not completely determined by cholesterol level and class of low density lipoprotein receptor mutations. AIM: To elucidate associations of some auxiliary genetic factors -- such as C151565T, C677T, R353Q polymorphisms of glycoprotein IIIa (GPIIIa), methylenetetrahydrofolate reductase (MTHFR) and coagulation factor VII genes, respectively, -- with the presence of IHD in patients with FHC. MATERIAL: Patients with clinical diagnosis of heterozygous FHC (n=198) with (n=106) and without (n=92) IHD. RESULTS: Patients with compared with those without IHD had similar frequency of T-allele of MTHFR gene (p=0.519), more often had T-allele of GPIIIa gene (23 and 12.5%, respectively, p=0.009), and less often -- Q-allele of factor VII gene (13 and 21%, respectively, p=0.048). Multifactorial analysis showed that risk of IHD was higher in patients with TT compared with CC genotype of the GPIIIa gene (OR 1.53, 95%CI 1.12-2.3), and lower in patients with RQ and QQ compared with RR genotype of factor VII gene (OR 0.41, 95%CI 0.19-0.75). CONCLUSION: In patients with FHC polymorphisms in factor VII and GPIIIa genes but not C677T polymorphism of MTHFR gene were associated with the presence of IHD.

Adult↗
PubMed2001

An invertebrate model of the developmental neurotoxicity of insecticides: effects of chlorpyrifos and dieldrin in sea urchin embryos and larvae.

Chlorpyrifos targets mammalian brain development through a combination of effects directed at cholinergic receptors and intracellular signaling cascades that are involved in cell differentiation. We used sea urchin embryos as an invertebrate model system to explore the cellular mechanisms underlying the actions of chlorpyrifos and to delineate the critical period of developmental vulnerability. Sea urchin embryos and larvae were exposed to chlorpyrifos at different stages of development ranging from early cell cleavages through the prism stage. Although early cleavages were unaffected even at high chlorpyrifos concentrations, micromolar concentrations added at the mid-blastula stage evoked a prominent change in cell phenotype and overall larval structure, with appearance of pigmented cells followed by their accumulation in an extralarval cap that was extruded from the animal pole. At higher concentrations (20-40 microM), these abnormal cells constituted over 90% of the total cell number. Studies with cholinergic receptor blocking agents and protein kinase C inhibitors indicated two distinct types of effects, one mediated through stimulation of nicotinic cholinergic receptors and the other targeting intracellular signaling. The effects of chlorpyrifos were not mimicked by chlorpyrifos oxon, the active metabolite that inhibits cholinesterase, nor by nonorganophosphate cholinesterase inhibitors. Dieldrin, an organochlorine that targets GABA(A )receptors, was similarly ineffective. The effects of chlorpyrifos and its underlying cholinergic and signaling-related mechanisms parallel prior findings in mammalian embryonic central nervous system. Invertebrate test systems may thus provide both a screening procedure for potential neuroteratogenesis by organophosphate-related compounds, as well as a system with which to uncover novel mechanisms underlying developmental vulnerability.

Animals↗
PubMed2001

[Cholinergic regulation of the sea urchin embryonic and larval development].

Choline esters of polyenoic fatty acids block cleavage divisions of sea urchins and evoke the formation of one-cell multinuclear embryos. If the fatty acids AA-Ch or DHA-Ch are added at the mid or late blastula stage, many cells are extruded, forming extra-embryonic cell clusters near the animal pole of embryos or larvae. Both effects are prevented by dimethylaminoethyl esters of polyenoic fatty acids (AA-DMAE or DHA-DMAE) or their 5-hydroxytryptamides. Nicotinic acetylcholine receptor antagonists, imechine, d-tubocurarine or QX-222 provide partial protection against AA-Ch or DHA-Ch. The organophosphate pesticide, chlorpyrifos, or a combination of (-)-nicotine + phorbol 12-myristate 13-acetate, also evoke the mass extrusion of transformed embryonic cells at the animal pole of larvae. These effects are similarly antagonized by AA-DMAE, DHA-DMAE, or fatty acids 5-hydroxytryptamides. Taking together, these results suggest that AA-Ch and DHA-Ch act on sea urchin embryos and larvae as agonists of acetylcholine receptors, whereas AA-DMAE and DHA-DMAE act as antagonists. The ability of fatty acids 5-hydroxytryptamides to prevent the effects of AA-Ch or DHA-Ch may be due to restoration of the normal dynamic balance of cholinergic and serotonergic signaling during cleavage divisions and gastrulation.

Acetylcholine↗
PubMed1995

[The clinical manifestations, diagnosis and treatment of diphtheria in adults].

Diphtheria morbidity among adult population of Moscow is growing. The tests of different modes and schemes of heterogeneous antidiphtheria serum administration have found out that the highest efficacy of serotherapy was achieved with a single intravenous dose. Another treatment of diphtheria is hemosorption. Widely used in present-day clinical practice hemosorbents provide adequate elimination of the toxin from plasma. The authors analyse the present situation in clinical symptoms, complications, lethality of diphtheria basing on the data provided by S. P. Botkin's Hospital.

Adolescent↗
PubMed1983

Opiate binding sites and endogenous opioids in Bufo viridis oocytes.

Binding sites with high affinity for [3H]naloxone, but not for [3H]morphine and [3H] (D-Ala2, D-Leu5) enkephalin, have been found in membranes of Bufo viridis oocytes. The binding is reversible and saturable. Bound [3H]naloxone is easily displaced both by unlabeled naloxone and bremazocine, much worse by morphine and SKF 10,047; (D-Ala2, D-Leu5) enkephalin and beta-endorphin practically fail to displace [3H]naloxone. Scatchard analysis is consistent with the existence of two classes of binding sites with Kd 15 nM and 10(3) nM. The number of binding sites with high affinity for naloxone is 16 pmol/mg protein of homogenized oocytes which is 20-50-fold higher than in, toad or rat brain. Oocyte extract displaces [3H]naloxone bound with oocytes' membranes and inhibits electrically evoked contractions of the rabbit vas deferens. This inhibition is reversed by naloxone. It is suggested that compounds similar to opiate kappa-agonists exist in oocytes. It cannot be ruled out that they participate via specific receptors in the regulation of oocyte maturation and egg development.

Animals↗
PubMed1976

[Transplantation of the nuclei of growing oocytes into the enucleated ova of the sturgeon].

The morphogenetic properties of nuclei (germinal vesicles) in the oocytes at the beginning of rapid growth have been studied by means of their transplantation in the enucleated eggs. Some opertaed eggs proceeded to gastrulation and were fixed at the midgastrula stage. The development of these embryos was provided by the transplanted oocyte nuclei and centrioles; the lampbrush chromosomes changes the character of their activity under the influence of the egg cytoplasm.

Animals↗
PubMedDate not supplied

[Arachidonoylcholine and N,N-dimethylaminoethyl arachidonate are new cholinergic compounds].

Choline and N,N-dimethylaminoethyl esters of arachidonic and some other fatty acids were synthesized. Experiments on the embryos and larvae of sea urchins, sensitive to cholinergic compounds, showed that arachidonoylcholine exhibited cholinomimetic activity similar to that of nicotine whereas N,N-dimethylaminoethyl arachidonate acted as an acetylcholine antagonist. The corresponding esters of docosahexaenoic acid displayed similar biological properties.

Animals↗
PubMedDate not supplied

[The possible functional interaction of serotonin and neuropeptides in embryogenic regulatory processes (experiments on embryos of the mollusk Tritona diomedea)].

Ritanserin and inmecarb hydrochloride, antagonists of serotonin, act cytostatically and teratogenically on early embryos of Tritonia diomedea, a nudibranch mollusk. On the basis of a pharmacological analysis and the type of developmental abnormalities observed, this action appears to be due to disturbances in the functional activity of endogenous serotonin and is associated with damage of to the cytoskeleton. The effects of ritanserin and inmecarb are prevented or attenuated by lipophilic serotonin analogs (serotoninamides of polyenoic fatty acids), as well as by polypeptides isolated from neurons Pd5 and Pd6 of the pedal ganglia of the adult Tritonia. In late embryos (stage of veligers), serotonin and to a lesser extent its lipophilic analogs strongly increase embryonic motility. This effect of serotonin is potentiated by some neuropeptides and inhibited by others. These results provide evidence for functional interaction between serotonin and neuropeptides in the control processes of embryogenesis.

Animals↗
PubMedDate not supplied

[Fluorescent-labeled lipophilic analogues of serotonin, dopamine, and acetylcholine: synthesis, mass spectrometry, and biological activity].

4,4-Difluoro-5,7-dimethyl-4-bora-3a,4a-diaza-s-indacene-3-dodecanoyl derivatives of serotonin, dopamine, choline, and N,N-dimethylaminoethanol, with the fluorescence maximum at 512 nm (lambda(exc) 470 nm), and 4,4-difluoro-5,7-diphenyl-4-bora-3a,4a-diaza-s-indacene-3-dodecanoyl derivatives of choline and N,N-dimethylaminoethanol, with the fluorescence maximum at 554 nm (lambda(exc) 470 nm), were synthesized. These compounds yield protonated molecular ions of 100% intensity upon mass spectrometry with electrospray ionization at atmospheric pressure. The fragmentation of molecular ions under the conditions of secondary mass spectrometry mainly proceeds through the elimination of hydrogen fluoride from the fluorescent core of the molecules. Experiments on sea urchin Lytechinus variegatus embryos and larvae showed that these compounds easily penetrate into the cells and are accumulated in the cytoplasm. They do not differ in their biological activity from similar derivatives of arachidonic acid described previously and are agonists of serotonin or acetylcholine or antagonists of nicotinic acetylcholine receptors. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2004, vol. 30, no. 5; see also http: // www.maik.ru.

Acetylcholine↗
PubMedDate not supplied

[Appearance of a factor stimulating oocyte maturation in the karyoplasm of the oocytes of the green toad, the clawed toad and the starred sturgeon].

The karyoplasm (the contents of germinal vesicle) of the Bufo viridis, Xenopus laevis, and Acipenser stellatus oocytes maturing under the influence of progesterone acquires the ability to induce the maturation (germinal vesicle breakdown) of the full grown oocytes, when injected into them. This ability arises in the karyoplasm earlier than in the cytoplasm and is preserved until the germinal vesicle breakdown.

Animals↗