[Ultramicroscopic evaluation of teeth enamel de- and remineralization].

The paper presents the results of scanning electronic microscopy evaluation of teeth enamel surface. The method allows studying objects at huge magnification and without preliminary preparation. Research was conducted in vitro on extracted teeth. Morphological features of tooth enamel were studied, as well as changes of enamel surface after application of remineralization agent.

Oxidized forms of fibrinogen induce expression of cell adhesion molecules by cultured endothelial cells from human blood vessels.

Oxidized forms of fibrinogen similarly to initial non-oxidized fibrinogen induced expression of P-selectin and ICAM-1 cell adhesion molecules in the cultured endothelial cells derived from human umbilical vein. The effect of oxidized fibrinogen on the expression of adhesion molecules was more pronounced. These data attest to more active participation of oxidized forms of fibrinogen into inflammation in the vascular wall, the first stage of atherogenesis.

[TNF-induced apoptosis and necrosis in myeloleukemia cells HL-60 is regulated by reactive oxygen metabolites depending on a cell cycle phase]. / TNF-indutsiruemyi apoptoz i nekroz v kletkakh mieloleikoza HL-60 reguliruetsia reaktivnymi metabolitami kisloroda v zavisimosti ot fazy kletochnogo tsikla.

UNLABELLED: TNF is the known death receptor ligand which induce apoptosis and necrosis. Reactive oxygen metabolites, ceramide (synthesized de novo and as a product of sphingomyelin cycle), and caspases have been implicated as potential mediators of cell death. Their mechanistic relationship remains to be elucidated. The presence and activation of executor caspase-3 has been found to be regulated during both TNF-induced apoptosis and necrosis on their early stages. TNF-induced cell damage, suggesting the induction of both, apoptosis and necrosis, depended on the cell cycle. Necrosis induced by TNF was inhibited by denitrophenol (DNP). Pretreatment of these cells with exogenous bacterial sphingomyelinase (SMase) potentiates TNF-alpha induced apoptosis only, suggesting the role of ceramide from sphingomyelin cycle in TNF signaling pathways of apoptosis. DNP was found to initiate necrosis after SMase and TNF common action. The role of ceramide synthesis in enhanced ceramide generation in response to oxidant stress was shown using inhibitor of ceramide synthase--fumonisin B1. Its effect was found to be modulated by mitochondrial chain respiration inhibitors. Monoclonal antibodies to TNF-alpha receptors R1 and R2 exhibit the more high level of necrosis compared with TNF and both regulated by DNP and phospholipase A2. TNF-R2 effect was not found previously. CONCLUSION: Ceramide synthesis and sphingomyelin breakdown, caspase activation and reactive oxygen metabolites production are required for the TNF-alpha-induced apoptosis and necrosis which may be regulated dependently on cell cycle. TNF-initiated necrosis seems to be the disrupted apoptotic program and may be classified as aponecrosis.

Effect of the triterpenoid miliacin on the sensitivity of lymphocytes in the thymus and spleen to dexamethasone-induced apoptosis.

We studied the effect of plant triterpenoid miliacin on dexamethasone-induced apoptosis in thymocytes and splenocytes. Miliacin produced a protective effect on splenocytes by decreasing the degree of DNA fragmentation due to blockade of the cascade cell death distally to the intramembrane phosphatidylserine translocation.

[The role of adhesion molecules (ICAM-1 and E-selectin) in development of diabetic microangiopathies]. / Rol' molekul adgezii (ICAM-1 i E-selektin) v razvitii diabeticheskikh mikroangiopatii.

AIM: To examine the expression of the intercellular adhesion molecule-1 (ICAM-1, CD54) on the surface of leukocytes and a soluble E-selectin (CD62) level in patients with diabetes mellitus type 1 (DM1) at various stages of diabetic nephropathy and retinopathy. MATERIAL AND METHODS: 42 patients with newly diagnosed and long-standing DM1 with presence or absence of microangiopathy (diabetic nephropathy and retinopathy) were examined. Routine laboratory, ophthalmologic tests, a special immunological test with ICAM-1 expression and soluble E-selectin (sES) examination were performed. RESULTS: The tests show increased ICAM-1 expression and sES level in all the patients vs controls. In newly diagnosed DM1 a high sES level was observed. In long-standing DM1 and absence of microangiopathy a sES level was also high. In patients with neovascularisation and proteinuria the sES level was two times higher than that in other subgroups. We also found an increased percentage of ICAM-1, CD54-positive lymphocytes and granulocytes in patients with microalbuminuria and especially with proteinuria and neovascularization. There were no correlations of ICAM-1 and sES levels with sex, DM duration, cholesterol and triglycerides. CONCLUSION: The findings show endothelium and leukocytes activation at early disease stages. Enhanced endothelium and leukocytes activation is associated with late complications.

[Monoclonal antibodies in oncology]. / Monoklonal'nye antitela v onkologii.

A start was made on explorations into hybridoma technologies at the N. N. Blokhin Russian Cancer Research Center in the late 1970s. ICO series monoclonal antibodies (MAb) against different human differentiation leukocyte antigens have been designed in a short period of time. MAb to antigens CD25, CD8, CDw50, CD5, CD4, CD7, CD3, CD71, CD34, CD45, CD38, CD11b, CD16, and CD95 have gained worldwide recognition at International HDLA Workshop Conferences. Today, the collection of hybridomas at the Center includes more than 200 samples. MAb are used for immunophenotypic assays of blood and bone marrow cells, for classification of lymphomas and leukemias, for assessment of human immunity for immunophenotypic diagnosis of minimal residual tumor in multiple myeloma. New prognostic markers in various nosological entities and MAb biological activity are under study. MAb have been used to develop ELISA diagnostic kits. They are employed as vectors for immunotoxin design, for immunomagnetic separation, many MAb-based drugs have been designed. A start has been made on the promising development of a new line of biopharmacy, namely design of new immunoliposomal dosage forms of doxorubicin and betulinic acids.

Production and specificity of monoclonal antibodies against nodularin conjugated through N-methyldehydrobutyrine.

Nodularin (Nod) is a cyclic pentapeptide hepatotoxin produced by the cyanobacterial genus Nodularia living in brackish waters and coastal lagoons. The toxicity of Nod is due to specific inhibition of the type-1 and type-2A intracellular protein phosphatases (PP1 and PP2A, respectively). We have developed a monoclonal antibody against Nod using chemical modification (aminoethylation) of one of its core amino acids, N-methyldehydrobutyrine. The developed antibody is highly specific for Nod, with negligible reactivity to the closely related cyanobacterial toxin microcystin (MC). The monoclonal antibody was employed for quantitative competitive ELISA assay. The analytical sensitivity of the assay was up to 0.2 ng/ml. Comparison of the developed ELISA test with HPLC-based measurements of Nod, with both laboratory and field samples, showed a good correspondence between the results yielded by these two methods. The antibodies developed by this technique provide means for developing extremely sensitive and specific analytical assays for direct measurement of nodularin and related toxins in cyanobacterial or water samples.

CD95 (FAS/APO-1) antigen is a new prognostic marker of blast cells of acute lymphoblastic leukaemia patients.

We analyzed CD95(Fas/APO-1) antigen expression on bone marrow blasts in 38 children with acute lymphoblastic leukemia (ALL) receiving a treatment in the Department of Leukaemias at the Cancer Research Center in 1987-1989 years (n = 22) and in 1994-1997 years (n = 16). CD95 antigen expression was studied by monoclonal antibodies (MoAbs) IPO-4 in indirect immunofluorescence analysis. CD95 antigen was expressed on 35.8 +/- 7.5% bone marrow blasts, most frequently (63.6%) in the clinically favourable Pre-B ALL. Only in this group CD95 antigen expression was correlated with CD10 antigen expression that has a positive influence to the time of complete remission in ALL patients. Our data showed that CD95 expression on blast cells is a favourable prognostic sign, associated with increased relapse-free and total survival. On the contrary, the absence of CD95 antigen on blasts is an unfavourable sign for disease evolution.

[An evaluation of the prognostic significance of antigen CD95(Fas/APO-1) expression on the cells of patients with a myelodysplastic syndrome, acute myeloid leukemia and chronic myeloleukemia]. / Otsenka prognosticheskoi znachimosti ékspressii antigena CD95(Fas/APO-1) na kletkakh bol'nykh s mielodisplasticheskim sindromom, ostrym mieloidnym leikozom i khronicheskim mieloleikozom.

AIM: The expression of CD95(Fas/APO-1) antigen was studied on bone marrow cells of 19 MDS patients, peripheral blood blast cells of 15 acute myeloid leukemia (AML) patients, blast cells and granulocytes of 68 patients with chronic myeloid leukemia (CML)--24 in chronic, 9 in accelerated phase and 35 in blastic crisis (BC)--by indirect surface immunofluorescence assay using flow cytometry (FACScan, Becton Dickinson, USA). RESULTS: CD95(Fas/APO-1) antigen was revealed on bone marrow cells of 8 out of 19 (36.8%) MDS patients; the percentage of antigen-positive cells was 38.1 +/- 19.2%; on 45.5 +/- 22.8% of cells in 6(45%) of 15 AML patients. Fas/APO-1 antigen was totally absent in CML chronic stage; its expression was found in 34% (12 of 35) of our patients with CML BC on peripheral blood blasts and in 56% (5 of 9) on peripheral blast cells of CML patients in acceleration phase. CONCLUSION: The data on overall survival of CD95-positive MDS patients suggest that the presence of Fas antigen is a favorable prognostic sign for patients with MDS. The patients from CD95-negative group represent a risk group both for survival and AML transformation. In CML BC group the survival does not depend upon Fas-antigen expression.

Fas (APO-1/CD95) Antigen: New Activation Marker for Evaluation of the Immune Status.

Using mAb ICO-160, we have studied Fas (APO-1/CD95) antigen expression on blood lymphocytes from healthy women, pregnant women and patients with chronic adnexitis, uterin myoma, ovarian cyst, ovarian and uterin cancer. In peripheral blood from healthy women Fas antigen was detected on 23.42 +/- 2.9% of lymphocytes. The healthy donors were divided in two different subgroups with low and high Fas expression. Expression of Fas antigen on lymphocytes was elevated (high expression subgroup) in all the groups of investigated patients, excepting the ovarian cancer ones with Fas expression similar to that in healthy donors. Comparison of expression of other differentiation antigens between healthy donors and the above groups of patients elucidated in the patients a kind of pronounced imbalance of the immune status and activation of the immune system. Additionally, in patients with ovarian cancer the imbalance of the immune status was reflected as altered ratio between helper and suppressor cells (the ratio was 0.73 in contrast to that 1.08 in group of healthy donors). As follows from the summarized results of all the trials, Fas antigen expression correlated with expression of other activation antigens as CD71 and CD25 (r = 0.05 and r = 0.52, respectively). Consequently, Fas (APO-1/CD95) antigen may be considered as the activation antigen and its expression may be used for assessing the immune status.

[Temperature causes structural and functional changes in lactate dehydrogenase from fish skeletal muscles]. / Temperatura vyzyvaet strukturnye i funktsional'nye izmeneniia laktatdegidrogenazy iz skeletnykh myshts ryb.

Adaptation of fishes to low and high environmental temperatures gives rise to certain changes in kinetic and structural properties of LDH from skeletal muscles. The KM versus temperature plot for pyruvate of the enzyme isolated from fishes adapted to low temperatures has a minimum at low measurement temperatures, whereas adaptation to high temperatures leads to the enzyme showing a minimum at high temperatures. The LDH isolated from fishes adapted to low environmental temperatures is more stable relative to both thermal and urea-induced inactivation. The differences in the kinetic properties of the enzymes from fishes adapted to low and high temperatures disappear after treatment with urea and subsequent reactivation.