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Biomedical subjects

T B Dmitrieva

Publications and source records attributed to T B Dmitrieva.

At least 19 recordsLinked to original sources

[The role of clinical suicidology in the system of measures directed towards lowering early mortality and increasing population life span].

The level of early mortality has increased substantially in Russia within the last fifteen years, having exceeded the same parameter in developed countries and in the entire post-Soviet area. The second frequent reason for early mortality is a group of factors that includes accidents, suicides, murders, and other external causes. The proportion of suicides in this group is 45 to 50%. As a result, in the recent years the suicide rate in Russia has filled the second place in the world. The authors of this article analyze the suicide rate in different Russian regions, distinguishing between regions with the highest and lowest rate, and characterizing population risk factors of suicidal danger, a special place among which is filled by socioeconomic condition of the regions and the ethnic composition of their population. Increase of the effectiveness of suicide prevention depends on creation of adequate scientific basis, which clinical suicidology can become. The authors substantiate the necessity to distinguish suicidology as a separate field of clinical medicine, and formulate its definition, goals and objectives. Basing on the obtained results, the authors come to a conclusion on the medico-social importance of the development of clinical suicidology in lowering early mortality and increasing the country's population life span.

Humans↗

[Direct drug delivery to the brain].

The authors of the review discuss the present-day state of and promising approaches to directed delivery of biological agents into the brain. Special attention is drawn to micellar and liposomal transport through the blood-brain barrier (BBB) targeted by immunochemical vectors, such as native or hydrophobized antibodies to specific antigens located at the BBB or in the brain parenchyma.

Biological Transport↗

Culturing of specialized glial cells (olfactory ensheathing cells) of human olfactory epithelium.

A monolayer of dissociated glial cells of human olfactory epithelium was cultured in Petri dishes and 12-well plates using a polylysine-laminin substrate. Primary cultures were subcultured after 10-15 days. The cell cultures were analyzed by phase contrast microscopy at all stages of culturing. A cytological study involved histological methods (trypan blue staining) and immunocytochemical visualization of GFAP, nestin, and low-affinity nerve growth factor receptors. At the final stage of culturing (5 passages) the monolayer cultures included 2 types of cells: GFAP- and p75-positive glial cells and nestin-positive fibroblasts.

Cells, Cultured↗

[The EEG correlates of delayed mental development in adolescents].

Fifty-eight male adolescents aged 15-17 years have been divided into 3 groups: 31 patients with mental infantilism syndrome were included in the study group, 14 with organic brain disorders--in the comparison group and 13 psychiatrically and neurologically normal subjects--in the control group. EEG was recorded from 12 leads monopolarly at rest, during hemisphere-specific cognitive tasks performance and exposure to aversive sound stimulation. Two-Hz wide EEG spectral ranges--A, theta1, theta2, alpha1 and alpha2--were analyzed. Only in the study group, there were decreased values of alpha2 spectral power (SP) and reduced reactivity to functional tests and insufficient lateral differentiation of the reactions during the cognitive tasks performance. Maximal deviation of the SP reactivity indices as compared to the comparison group was found in alpha2 range. The disturbances obtained indicate the delay of brain maturation and retardation in formation of specific neural networks. The results of the study demonstrate that indices of alpha2 SP may be considered as objective criteria of delayed mental maturation.

Adolescent↗

Selective accumulation of monoclonal antibodies against neurospecific enolase in brain tissue of rats with middle cerebral artery occlusion.

Preparations of I(125)-labeled monoclonal antibodies against neurospecific enolase and mouse plasma IgG1 were injected intravenously to rats immediately after unilateral occlusion of the middle cerebral artery. Radioactivity of I(125)-labeled monoclonal antibodies against neurospecific enolase in the brain tissue progressively increased, reached a maximum by the 48th hour, and remained practically unchanged after 72 h. At the same time radioactivity of labeled IgG1 in the brain tissue and radioactivity of both preparations in the blood, liver, spleen, kidneys, heart, and lungs decreased over 72 h. Selective accumulation of I(125)-labeled monoclonal antibodies against neurospecific enolase was less significant in the brain tissue of the contralateral hemisphere and cerebellum not exposed to ischemia.

Animals↗

[Modeling of focal ischemia of the brain].

Methods of modeling and criteria of evaluating the pathological process in the central nervous system (CNS) as well as modern technologies of provoking the focal ischemia of the brain in experimental animals are under discussion. The results were analyzed comparatively from the viewpoint of efficiency and adequacy of certain models as well as of the clinical specificity of ischemic strikes in man and of set research goals. A literature analysis confirms that the existing arsenal of methodical schemes provides for choosing the most adequate model of focal ischemia of the brain and to ensure a cerebral infarction of a preset scope and localization; it makes possible also an objective evaluation of pathological processes occurring in the cerebral tissues both at the earliest stages of ischemic lesion and during a relatively long time period comparable with rehabilitation time period. Achievements in the sphere of experimental modeling of focal ischemia of the brain pave the way to further promotion of experimental therapy in acute stroke and open up new research priorities; it concerns primarily research of mechanisms timing the neurodegenerative process after ischemic stroke as well as searching-for and testing of means of stroke prevention and of patients' rehabilitation.

Animals↗

[Liposome-oriented transport of therapeutic drugs].

The attempts to use liposomes as containers for the transport of therapeutic drugs have been undertaken during the recent 40 years. However, the first success was achieved only in the 80-ies, when the sterically stabilized liposomes were invented. It was found that the liposome biological layer modified through, adding to it, certain polymers prolonged the blood circulation and reduced the capture of liposomes by RES cells. Elaboration of immunoliposomes, i.e. those conjugated with antibodies, was the next step in the path of perfecting the liposomes as a transport tool for the sake of binding with target-cells and to ensure the address-oriented delivery of drugs to a pathology focus. Preclinical and clinical testing of liposome-form of antitumor drugs witnessed to their lower toxicity and better pharmacokinetic indices; besides, they selectively accumulate themselves in tumor cells and have a more pronounced therapeutic effect even at lower doses of drugs in case of tumors resistant to the already made chemotherapy.

Animals↗

Enzyme immunoassay of NSE and GFAP as the criterion of dynamic evaluation of the rat blood-brain barrier in perinatal hypoxic ischemic injury of the CNS.

Enzyme immunoassay of the serum neurospecific antigens (gliofibrillar acid protein and neurospecific enolase) was used for evaluation of the resistance of the blood-brain barrier in Wistar rats with perinatal hypoxia and ischemia of the CNS. Perinatal hypoxia and ischemia of the CNS was modeled by two methods: ligation of the common carotid artery in 7-day-old rats followed by 3.5-h hypoxic hypoxia or 15-min anoxic exposure of fetuses isolated via hysterectomy on day 21 of gestation. Enzyme immunoassay of serum gliofibrillar acid protein and neurospecific enolase in control an experimental rat pups was carried out once a week during 3 months. In controls serum levels of gliofibrillar acid protein and neurospecific enolase virtually did not change during postnatal development, while in animals with cerebral hypoxia and ischemia induced in fetuses by both methods serum concentration of neurospecific enolase sharply increased 1 week after the injury and increased on weeks 6 and 10. The content of gliofibrillar acid protein was maximum on week 1 and later considerably varied, the peaks of its concentrations observed on weeks 3 and 8 preceded the increase in neurospecific enolase activity in peripheral blood.

Animals↗

Comparison of the efficacy of cell preparations from embryonic ventral mesencephalon of various prenatal age transplanted intrastriatally to rats with 6-OHDA-induced Parkinsonism.

Cell preparations of ventral mesencephalon obtained from 8-, 14-, and 16-17-day rat embryos were stereotactically transplanted to homologous rats with 6-hydroxydopamine-induced hemiparkinsonism. Automated analysis of apomorphine-induced motor asymmetry for 3 months after neurotransplantation revealed higher efficacy of cell preparations from 8- and lower from 16-17-day-old embryos. These data correlated with histomorphological findings, in particular, with the size of grafts, glial reaction, and the number of dopaminergic neurons in the grafts.

Animals↗

Immunoenzyme assay of glial fibrillary acidic protein for evaluation of functional activity of cell grafts from embryonic ventral mesencephalon in rats with experimental hemiparkinsonism.

The relationship between the release of glial fibrillary acidic protein (GFAP) into systemic circulation and the efficacy of transplantation of embryonic nervous tissue was studied on rats with 6-OHDA-induced hemiparkinsonism. It was found that intrastriatal transplantation of cell preparations from embryonic ventral mesencephalon significantly attenuated apomorphine-induced rotation, which points to functional recovery of the dopaminergic nigrostriatal system. The degree of this recovery depends on reactive astrogliosis around the graft and survival of dopaminergic neurons. Analysis of GFAP concentration revealed significant elimination of this antigen into the circulation 7 and 14 days after transplantation. In rats with good consolidation of the graft without pronounced reactive gliosis, the concentration of GFAP reached 253.99+/-79.30 ng/ml on week 4 after transplantation and decreased to 8.2+/-3.3 ng/ml 8-12 weeks after transplantation. In rats with poor graft consolidation associated with death of transplanted neurons and gliosis in the graft and surrounding tissue the concentration GFAP increased to 476.4+/-111.0 ng/ml within 4 weeks after transplantation and remained elevated (235.0+/-44.8 ng/ml) for 12 weeks. Thus, monitoring of serum GFAP concentrations allows in vivo evaluation of the functional state of intracerebral graft and the level of reactive gliosis. This test can be used for the prognosis of transplantation efficacy.

Animals↗

Monoclonal anti-GFAP antibodies: extraction, characteristics, and immunoenzyme assay.

Methods of GFAP purification and obtaining of hybridoma cells producing monoclonal anti-GFAP antibodies and properties of GFAP preparation were described. The immunobloting data on specificity of obtained monoclonal antibodies are presented. A new method of GFAP immunoenzyme assay based on GFAP preparation and anti-GFAP antibodies was elaborated. Standardization of the immunoenzyme system was shown in tests for specificity, accuracy, and reproducibility.

Animals↗

Catecholamines and their metabolites in the brain and urine of rats with experimental Parkinson's disease.

The content of catecholamines and their metabolites in the brain and the relationship between cerebral catecholamine levels and their urinary excretion were studied in rats with 6-OHDA-induced hemiparkinsonism. 6-OHDA reduced brain concentrations of dopamine, DOPAC, and homovanilic acid and urinary excretion of dopamine, dioxyphenilalanine, and DOPAC by more than 90%. A positive correlation was found between the concentrations of these metabolites in the urine and striatum. Measurement of urinary catecholamines and their metabolites is a perspective test for evaluating the status of the dopaminergic nigrosostriate system of the brain in experimental parkinsonism.

3,4-Dihydroxyphenylacetic Acid↗

Complex analysis of efficiency of transplantation of embryonic nerve tissue to rats with hemiparkinsonism.

Effect of transplantation of embryonic ventral mesencephalon preparation containing dopaminergic neurons on repair of the dopaminergic nigrostriatal system was studied in rats with hemiparkinsonism induced by 6-hydroxydopamine. Transplantation of embryonic ventral mesencephalon into denervated striatum led to a more than 50% decrease in apomorphine-induced rotation, recovery of dopamine and DOPAC levels in the brain, and to an increase in DOPAC excretion and the DOPAC-dopamine ratio in daily urine of rats with hemiparkinsonism. Dopaminergic neurons of the transplant survived, forming a network of tyrosine hydroxylase-positive processes growing beyond the transplant and reinnervating the adjacent compartments of the striatum. A positive correlation between urinary excretion of DOPAC and brain concentration of dopamine was revealed in denervated rats after transplantation of ventral mesencephalon. Intrastriatal transplantation of cell preparations of embryonic striatum containing no dopaminergic neurons and isolated local injury to the striatum did not affect regeneration of the denervated nigrostratal system.

3,4-Dihydroxyphenylacetic Acid↗