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PubMed2002

[The intestinal microenvironment in healthy persons under the technogenic action of an industrial city].

The intestinal microflora was studied in 806 healthy persons residing in three different environmental areas of the city of Volgograd. The study indicated that there were qualitative and quantitative differences in its composition, the heterogenicity of microbiocenosis being due to the degree of ambient air pollution. The changed found allowed four cenotypes (normal variants) of the microflora to be identified in urban residents. As the technogenic burden was ascertained to increase on the population, there was a rise in the incidence of atypical variants of the microflora, which were detectable at a rate of 30.6% in the ecologically good central area whereas their rates were 63.3 and 74.9% in both a northern and a southern areas where the basic enterprises of chemical and metallurgic industries are located.

Adolescent↗
PubMed1992

[The role of the hemopoiesis-inducing microenvironment in the mechanisms of the regeneration of hemopoiesis after cytostatic exposure].

On the model of adriamycine-induced hemopoiesis hypoplasia it has been shown that the accelerated differentiation of hemopoietic precursors regeneration is of great importance in regeneration of hemopoiesis. This differentiation is provided by preceded recovery of bone marrow structural-functional organization. The important role in regeneration of hemopoiesis belongs to hemopoietic microenvironmental elements which express its induced influence by the increase of colony-stimulating and erythropoietic activities, interleukin-1 and interleukin-3 production.

Animals↗
PubMed1992

Microenvironment at the substrate binding subsite of the active site of UDPglucose 4-epimerase from Kluyveromyces fragilis using a fluorescent analog of UMP.

A chromophorics and fluorescent analog of uridine 5'-monophosphate (UMP), a known competitive inhibitor of UDPglucose 4-epimerase was synthesised. This analog, namely 2',3'-O-(2,4,6-trinitrocyclohexadienylidene) uridine 5'-monophosphate, was found to be a powerful reversible inhibitor of UDPglucose 4-epimerase indicating its interaction with the substrate binding site of the enzyme. The extreme sensitivity of the fluorescence emission spectrum of this analog to solvent polarity makes it an excellent probe for the study of the environment at the active site of the enzyme. We report here the effective use of this UMP analog to demonstrate that the hydroxyl groups of the ribose moiety of UMP and presumably the substrates (UDPgalactose and UDPglucose) do not reside in a hydrophobic milieu.

Binding Sites↗
PubMed1992

[Role of T-lymphocytes in the mechanisms of hemopoiesis-inducing microenvironment activation in inflammation].

On the model of acute infectious peritonitis in mice, the inflammation was shown to accompany pronounced activation of bone marrow haemopoiesis. The increased number of committed precursor cells of erythro- and granulomonocytopoiesis, morphologically differentiated elements and enhancing colony-stimulating and erythropoietic activities of GIM cells origin were shown as well. Thy 1.2+ cells, migrating to bone marrow, were shown to play an important role in hemopoiesis stimulation inflammation. These stimulate the processes of myeloid precursor proliferation directly (by means of lymphokines) and in cooperation with monocytes-macrophages of GIM.

Acute Disease↗
PubMed2003

Multidrug resistance in cancer therapy: role of the microenvironment.

Despite advances in the design of chemotherapeutic agents, and although many of these effective agents are now available for clinical use, most human cancers are resistant to therapy at presentation or become resistant after an initial response. The effectiveness of chemotherapy is compromised by several microenvironmental factors that affect the bioavailability and efficacy of chemotherapeutic agents. These factors vary from one tumor to another, and from one location to another, within the same tumor. A better comprehension of microenvironmental multidrug resistance mechanisms would lead to a clearer understanding of the reason for chemotherapeutic failure. This improved knowledge will permit a more rational utilization of chemotherapy.

Animals↗
PubMed1978

Studies of the hemopoietic microenvironments: effects of acid mucopolysaccharides and dextran sulphate on erythroid and granuloid differentiation in vitro.

The effects of acid mucopolysaccharides (AMPS) on in vitro erythrocytic and granulocytic colony formation of murine bone marrow cells have been studied. High concentrations of chondroitin sulphate A, B and C and heparitin sulphate partly or completely inhibited the response of CFU-E to erythropoietin stimulation whereas addition of heparin, hyalyronic acid and keratan sulphate II in concentrations up to 100 microgram/ml did not elicit an inhibition of erythrocytic colony formation. The granulocytic colony formation was not significantly affected by AMPS-addition under these circumstances. Low concentrations of chondroitin sulphate A and B evoked a stimulatory effect on the CFU-E number. The synthetic polyanion dextran sulphate did not affect the erythrocytic and granulocytic colony formation. It is concluded that AMPS can affect the in vitro erythrocytic proliferation and differentiation in concentrations which do not affect the granulocytic maturation. Since stromal cells, i.e. macrophages and reticular cells, in bone marrow in vivo have the ability to produce and remove AMPS in the extravascular matrix we postulate that stomal cells may be involved in the regulation of erythroid progenitor cell maturation.

Animals↗
PubMed1992

Synthesis and deposition of glycosaminoglycans in the murine hemopoietic stromal line S17: modulators of the hemopoietic microenvironment.

The murine hemopoietic stromal cell line S17 can support either myelopoiesis or lymphopoiesis depending on the culture conditions (i.e., the presence of steroid or mercaptoethanol). The glycosaminoglycans are important components of the extracellular matrix, which influence hemopoietic cell proliferation. Accordingly, glycosaminoglycans have been compared under different growth conditions. Under myeloid conditions (with steroid) a higher proportion of the sulfated glycosaminoglycans was incorporated into the cell layer and the extracellular matrix was increased, whereas synthesis was reduced under lymphoid conditions (with mercaptoethanol). The inclusion of steroid or mercaptoethanol did not alter the nature of the heparan sulfate synthesized as shown by DEAE anion-exchange chromatography, cleavage with specific enzymes and resolution of the digestion products by gel electrophoresis (oligomapping), and glycosaminoglycan size. The major species of sulfated proteoglycan synthesized under the different growth conditions (200 and 110 kd for the culture supernatant and 110, 71, and 38 kd for the cell layer) were shown to be very similar by polyacrylamide gel electrophoresis. Although no qualitative difference was found biochemically between the major glycosaminoglycans/proteoglycans, scanning electron microscopy revealed major differences in the pattern of deposition of the glycosaminoglycans. Under myeloid conditions, a rich fibrous matrix covered the cell layer, whereas under lymphoid conditions glycosaminoglycan was sparsely deposited. The arrangement of the extracellular matrix may have important consequences for myelo- and lymphopoiesis.

Animals↗
PubMed2004

[Effect of forest litter on microenvironment conditions of forestland].

Litter is a very important component in forest ecosystem. This paper made a systematic review on the previous studies about the effects of litter on forestland microsites. Litter significantly reduced the light on the soil surface of forestlands, and the light transmittance was varied with the type, water content and weight of litter. The spectral composition of the light was dramatically shifted to longer wavelengths after transmitted through forest capony, especially through moist litter leaves, intact forest litter, and even the thinner soil layer, which greatly reduced the R/FR ratio and PPFD (photosynthetic photo flux density) beneath litter and surface soil (2 mm depth), and resulted in a stronginhibitory effect on the germination of photoblastic seeds, and on the growth of seedling and sapling. It was the reason why the appearance of massive numbers of pioneer plants and their successful establishment required relatively large gaps of the forest canopy. Many references concerned the effects of litter on soil nutrient cycling and water and soil conservation. The previous studies indicated that litter could create a moist micro-site above soil, and make soil more moist and fertile. Furthermore, litter could also increase the numbers of arthropods such as Carabidae adults and larvae, crickets, millipedes, spiders, ants and others. An increase in the activity of herbivorous arthropods might produce the negative effects on the establishment of individual seedlings. Although the mechanical barrier of litter was neglected in the paper, litter might act as a mechanical impediment to the emergence of the seedlings of pioneer species with small seeds. The effects of litter on micro-sites were of complexity because it varied greatly with the density, age, structure and species composition of the canopy, sunfleck frequency, presence of gaps, as well as litter thickness, moisture, and species composition, and also with climate and topography factors. The effects of litter were comprehensive, including positive and negative effects on seed germination and seedling growth. Each effect of litter on regeneration was dependent on species physiology, litter physical properties and environmental conditions. Therefore, it should be encouraged to integrate the physical properties (such as changing light, temperature and moisture) of litter with the physiological ecology (including seed, germination and growth natures) of species, and with environment (vegeneration, climate and topography propersities) on the basis of combination of regeneration patterns of litter, understory and gap scales.

Animals↗
PubMed1992

In situ lacZ retrovirus-marked lymphocytes define a B cell microenvironment in the lymph node medulla.

A recombinant nonreplicating retroviral vector bearing the Escherichia coli lacZ indicator gene was used to mark a population of B cells in situ in murine lymphoid tissue. The retrovirus was surgically injected into popliteal lymph nodes during the primary immune response to DNP-CGG when B cell proliferation in the germinal centers was maximal. LacZ+ cells were initially detected in the perivascular medullary interstitium, where they expanded and persisted up to 2 weeks following retrovirus injection. Migrant lacZ+ B cells were detected in the spleen 3-18 weeks following immunization and resided in the red pulp or marginal zones. Two-color flow cytometric analysis using a fluorogenic substrate for beta-galactosidase revealed that lacZ+ cells bear kappa light chains and that at least 50% of these cells bound the hapten, DNP. Based on their location, life span, migratory capacity, antigenic specificity, and surface immunoglobulin density, lacZ+ cells define a distinct nonfollicular B cell population associated with other late developmental stages of B lymphocytes, including memory and plasma cells.

Animals↗
PubMed2004

[The study of peptide effect in the mechanisms of angiogenesis and forming of microenvironment of the tumors in old rats].

The experiments were performed in rats with transplanted sarkoma M-1. The injections of synthetic peptide vilon at the doses 0.5 mcg sigificantly increased the apoptosis of tumor cells in the experiment as compared to the control group. So vilon has possessed the oncomodulating action on the transplanted carcinoma. The injections of epigene lead to the inhibition of the sarcoma growth due to the development of the hemorragic necrosis and apoptosis increased. The results obtained suggested that vilon and epigene are the perspective preparates in the cancer therapy.

Angiogenesis Inhibitors↗