Biomedical subjects

M D Pavlović

Publications and source records attributed to M D Pavlović.

13 recordsLinked to original sources

PubMed2007

Expression of heat shock protein 70 (HSP70) in patients with colorectal adenocarcinoma--immunohistochemistry and Western blot analysis.

The role of heat shock protein 70 (HSP70) expression has been investigated in various types of tumors. There are only little and controversial data about its clinical relevance in colorectal carcinoma, one of the most common carcinomas observed in humans. In this study we investigated expression of HSP70 in human colonic carcinoma and possible correlation with clinicopathology. To assess patterns (cytosolic and membrane) of HSP70 expression, the 48 surgically removed colorectal adenocarcinomas and 12 normal colonic and rectal mucosal samples were examined by immunohistochemistry and Western-blot. According to results of immunohistochemistry, expression of cytoplasmic HSP72 was significantly higher in colorectal carcinoma compared with normal and adjacent mucosa (p<0.01). In addition, there was significant increase in HSP72 expression in lymph node-positive compared to node-negative group (p<0.001). Dukes C2 stage of colonic cancer showed significantly higher immunohistochemical score than Dukes B2 and B1 stage groups (p< 0.05 i.e. p< 0.02). There was no relation between expression of HSP72 and degree of tumor differentiation. Using Western blot analyses, we noticed elevated levels of cytosolic HSP70 in colorectal cancer cells compared to normal. Densitometric analysis of blots of plasma membrane HSP70 expression has shown decrease in colorectal cancer cells compared to normal mucosa. According to our results, overexpression of HSP72 in malignant tissues of patients with colorectal carcinoma is related to tumor progression, suggesting that these proteins could play an important role not only in tumorigenesis but also in the development of drug resistance. Further research is necessary to clarify the mechanisms responsible for differential HSP70 expression as well as its definitive role in colorectal cancer.

Adenocarcinoma↗

PubMed2006

Lupus band test and disease activity in systemic lupus erythematosus: does it still matter?

BACKGROUND: Lupus band test still has no clearly defined position within either diagnostic or disease activity measuring tools for systemic lupus erythematosus (SLE). OBJECTIVES: We tested the hypothesis that positive LBT correlates with global activity of SLE measured by the SLE Disease Activity Index (SLEDAI) score. METHODS: In total, 90 SLE patients who underwent biopsy of sunprotected non-lesional (SPNL) skin were studied prospectively. The skin specimen was processed for standard direct immunofluorescence. The patients were classified into groups as negative and positive LBT, and the latter were further subdivided on the basis of the type and morphology of the deposits. Every patient was thoroughly examined and assigned a SLEDAI score. The relationship between LBT findings and SLEDAI score was analysed. RESULTS: The disease was significantly more active in patients with positive LBT and in those with a higher number of deposited immunoreactants. Almost all patients with renal involvement had a positive LBT. CONCLUSIONS: LBT on SPNL skin may be a good marker of severe disease at presentation, particularly when three immunoglobulins are found at the dermoepidermal junction.

Acute Disease↗

PubMed2004

Pyoderma gangrenosum with spleen involvement and monoclonal IgA gammopathy.

A 46-year-old man with a 3-year history of pyoderma gangrenosum was admitted with ulceration (6 x 5 cm), on the right leg. Previously he had been treated with tapering doses of prednisone (maximum dose 1 mg/kg per day); however, he had had a few exacerbations following each taper of prednisone dose. Immunoelectrophoresis demonstrated monoclonal IgA gammopathy of lambda light chains. Abdominal echography and abdominal computed tomographic scan revealed multiple splenic abscesses. Treatment was started with oral prednisone (1 mg/kg per day) and cyclosporin (5 mg/kg per day) and 6 weeks later complete remission was achieved. Systemic involvement in pyoderma gangrenosum is very rare, and according to our knowledge there are only a few cases with spleen involvement.

Cyclosporine↗

PubMed2004

Recrystallization in different sunscreen formulations after cutaneous application.

BACKGROUND: Data on the structure of sunscreens prior to and after application to the skin and the possible impact of these factors on their efficacy are still scant. AIMS: The microscopic structure of several commercial sunscreen products containing benzophenone-3 (BP-3) was analysed under a light microscope, prior to and 2 h after application of the products to the skin, and compared with various control preparations with or without BP-3. METHODS: All tested formulations were mounted on microscope slides, viewed under a light microscope and photographed. Samples were taken directly from original packages or from freshly prepared prescription formulations. Two hours after application to the skin, the samples were taken and processed for microscopy. RESULTS: In some commercial sunscreens numerous crystals were formed upon cutaneous application, whereas others contained crystals both prior to and after epicutaneous application. A single commercial product (a lamellar ambiphyl emulsion, SPF28) retained its regular structure throughout the study. Control preparations with or without BP-3 and/or octyl methoxycinnamate contained crystals after cutaneous application. CONCLUSIONS: Ingredients, most probably BP-3, in many commercial sunscreens are prone to recrystallization while on the skin which might interfere with their UV light-absorbing function.

Journal Article↗

PubMed2001

Persistent erythema multiforme: a report of three cases.

Three cases of persistent erythema multiforme, two of unknown aetiology and one precipitated by influenza are reported. Lesions were widespread, mostly atypical in appearance and regressed in response to immunosuppressants (systemic steroids and/or azathioprine) or, in one case, to dapsone. One patient developed erythroderma responding eventually to etretinate. Histology in all patients was consistent with the mixed, epidermodermal pattern of erythema multiforme. There were no significant laboratory abnormalities nor marked symptomatology apart from itching. The persistent form appears to belong to the spectrum of erythema multiforme being heterogeneous with respect to inducing stimuli, including viral antigens, neoplastic or inflammatory disease or unknown causes. Whenever it is possible, treatment should be adjusted depending on the causative agent.

Adult↗

PubMed2001

Skin lesions--an indicator of disease activity in systemic lupus erythematosus?

Cutaneous manifestations have great diagnostic value for systemic lupus erythematosus (SLE). In this study we tried to establish a correlation between lupus erythematosus LE-specific and LE-nonspecific cutaneous lesions and disease activity measured by the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI). Sixty-six patients with SLE were evaluated. They were divided into three groups having: (1) only LE-specific lesions (38 or 58.46%); (2) only LE-nonspecific lesions (4 or 6.15%); and (3) both types of lesions (23 or 35.38%). Results were analyzed using the Student t-test. Patients with LE-nonspecific skin manifestations had significantly increased disease activity compared to those with only LE-specific lesions. The number of different skin lesion types also correlated with disease activity. It was significantly increased in a group with three different types of lesion, either specific or nonspecific. Patients with only one type of lesion had mild disease. An intermediate disease activity was found in the group with two different lesion types. Lupus-specific skin manifestations serve primarily as an important diagnostic clue. In conclusion, patients with LE-nonspecific lesions have significantly more active SLE than those with LE-specific lesions and may therefore require more intensive therapy and disease monitoring.

Adult↗

PubMed1997

Bullous delayed pressure urticaria; pressure testing may produce a systemic reaction.

We report a patient with bullous delayed pressure urticaria (DPU) and chronic idiopathic urticaria (CIU) in whom a systemic reaction occurred. The reaction occurred 18 h after a pressure test had been performed on the right forearm. Blood histamine levels were more elevated in the sample taken from the forearm on which the test had be applied. Skin biopsy revealed both intraepidermal and subepidermal bullae with a sparse dermal inflammatory infiltrate and direct immunofluorescence showed linear deposition of fibrinogen along the epidermodermal basement membrane. As far as we are aware this is only the third case of bullous DPU reported and the first associated with generalized urticaria and angioedema and severe broncho-obstruction. Possible pathophysiological mechanisms are discussed.

Adult↗

PubMed1996

Mechanisms involved in the binding of thymocytes to rat thymic dendritic cells.

The effects of monoclonal antibodies (mAbs) to cell-surface molecules, divalent cations, and various cell-signaling and metabolic inhibitors on the binding of thymocytes to rat thymic dendritic cells (TDC) were studied using a rosette assay. It was found that TDC/thymocyte adhesion was stronger and faster at 37 degrees C than at 4 degrees C. Flow cytometric analysis demonstrated that bound thymocytes were predominantly CD4+CD8+ and CD4+CD8-, but in comparison to the phenotype of whole thymocytes, they were enriched in the mature TCR alpha beta hi subset. The binding of thymocytes to TDC at 37 degrees C was almost completely dependent on Ca2+ and Mg2+ and partly on an intact cytoskeleton and calmodulin-dependent protein kinase. The adhesion was independent of new protein synthesis and the activities of protein kinases A and C, tyrosine kinases, as well as phosphotyrosine protein phosphatases. The TDC/thymocyte adhesion at 37 degrees C was partly blocked by anti-LFA-1 (WT.1), anti-CD18 (WT.3), and anti-ICAM-1 (1A29)mAb. MAbs to class II MHC (OX-3 and OX-6), CD4 (W3/25), CD8 (OX-8), and alpha beta TCR (R73) stimulated the adhesion via an LFA-1-dependent pathway, whereas an anti-CD45 mAb (G3C5) stimulated the rosette formation independently of LFA-1. MAbs to CD2 (OX-34), CD11b (ED7), CD11b/c (OX-42), and class I MHC (OX-18) were without significant effects on the adhesion process.

Animals↗

PubMed1994

A novel anti-rat CD18 monoclonal antibody triggers lymphocyte homotypic aggregation and granulocyte adhesion to plastic: different intracellular signaling pathways in resting versus activated thymocytes.

We have raised a monoclonal antibody (mAb), NG2B12, directed against rat CD18, capable of inducing lymphocyte homotypic adhesion and granulocyte adherence to plastic. NG2B12-induced aggregation is temperature sensitive and requires metabolic energy, an intact cytoskeleton and the presence of Mg2+, but is independent of protein synthesis. Ca2+ is not only dispensable but exerts a suppressive effect on the NG2B12-induced adhesion. The adhesion is readily observed in thymocytes and concanavalin A blasts of thymocytes and splenocytes but is very weak in resting spleen and lymph node cells. NG2B12 also enhances phorbol 12-myristate 13-acetate (PMA)-induced aggregation in an additive fashion. The NG2B12-induced homotypic adhesion is mediated by LFA-1. mAb against ICAM-1 completely inhibited the induced adhesion of activated cells but inhibited only partially and in a time-dependent manner the adhesion of resting thymocytes. The activation of protein phosphatases 1 and 2A (as assessed by the use of okadaic acid) is necessary for the NG2B12-induced adhesion of both resting and activated thymocytes. In contrast, H-7 (an inhibitor of protein kinase C and A), substantially suppressed the adhesion of resting thymocytes, whereas W-7 (an inhibitor of calmodulin-dependent protein kinase) inhibited the adhesion of activated thymocytes. NG2B12 induces both adherence to plastic and homotypic aggregation of granulocytes; the events being blocked by anti-CD18 (WT.3) and anti-CD11b/CD11c (OX-42) mAb, augmented by okadaic acid and not modified by H-7 and W-7. Additionally, we have demonstrated that NG2B12 and PMA employ distinct intracellular signaling pathways in inducing adhesion of both thymocytes and granulocytes.

Animals↗

PubMed1994

Role of beta 2 integrins in the binding of thymocytes to rat thymic macrophages.

A role of beta 2 integrins and one of their ligands, ICAM-1, in thymic macrophage (TMF)/thymocyte interactions was studied. TMF were isolated as adherent cells from 4-day old culture of thymic-cell suspensions either from normal or hydrocortisone-treated rats. Adherent cells were 94-98% positive with ED1 (a pan-macrophage marker). The majority of them (75-95%) expressed the CD11b and CD18 molecules, and 60-70% expressed CD54 (ICAM-1). A low proportion of TMF (10-20%) expressed CD11a (LFA-1). The expression of all these antigens was upregulated by IFN-gamma and TNF-alpha. The effect of these mAbs on TMF/thymocyte binding was studied using a simple rosette assay by incubating unstimulated or IFN-gamma or TNF-alpha stimulated TMF, grown on microscopic slides with resting or ConA+IL-2 activated thymocytes. It was found that LFA-1/CD18 and ICAM-1 play a significant role in the TMF/thymocyte adhesion. In addition, a LFA-1-dependent/ICAM-1-independent adhesion pathway was observed, suggesting that LFA-1 might use another ligand. The inhibitory effect of anti-CD18 mAb (WT-3) was higher than the effect of anti-LFA-1 mAb (WT-1) and was a consequence of blocking the CD18 chain both on thymocytes and TMF. No significant difference in the expression and function of adhesion molecules was found between TMF obtained from normal or hydrocortisone-treated rats. The involvement of CD11b in these processes was of lesser importance than the role of the CD11a molecule. By using mAbs to different epitopes of the CD11b molecule, such as OX-42 (anti-CD11b/CD11c), ED7, and ED8 (anti-CD11b), it was found that they were either slightly or moderately inhibitory under certain experimental conditions or did not significantly modulate TMF/thymocyte binding. OX-42 was slightly stimulatory in some experiments. Cumulatively, these results show that beta 2 integrins play a significant role in TMF/thymocyte interactions and probably contribute to T-cell development in vivo.

Animals↗

PubMed1994

An adhesion-promoting anti-rat CD18 monoclonal antibody differentially alters thymocyte responses to various mitogens.

Leukocyte function-associated antigen (LFA)-1 represents one of the major lymphocyte adhesion molecules being capable of both strengthening cell-cell contacts and cooperating with other relevant surface molecules in signal transduction. We have studied the effects of an adhesion-promoting anti-CD18 monoclonal antibody (mAb) (NG2B12) on thymocyte proliferation induced by various mitogens. As we have recently described, the adhesion-promoting function of this mAb strictly depends upon the activation of several intracellular protein kinases and phosphatases. In the present work we have found that NG2B12 inhibits concanavalin (Con) A-induced thymocyte proliferation suppressing IL-2 production by these cells. Conversely, this mAb enhances proliferative responses of thymocytes to phytohemagglutinin (PHA) and interleukin (IL)2 alone or in combination with the phorbol ester PMA. The effects of this mAb were compared with those of another anti-rat CD18 mAb which potently blocks the LFA-1/Intercellular adhesion molecules (ICAMs) interactions.

Animals↗

PubMed1994

Adhesion molecules involved in the binding and subsequent engulfment of thymocytes by a rat thymic epithelial cell line.

A rat thymic epithelial cell (TEC) line (R-TNC.1) was established from a long-term TEC culture. Based on its ultrastructure, phenotype and cytokeratin profile, this line was characterized as a type of cortical TEC. R-TNC.1 cells had nursing activity which was manifested by the binding and subsequent engulfment of thymocytes. The role of adhesion molecules involved in these processes was studied extensively using a coculture of resting thymocytes and unstimulated or interferon-gamma (IFN-gamma)-stimulated R-TNC.1 cells. It was found that a number of adhesion molecules, such as CD2, CD4, CD8, LFA-1, CD18, ICAM-1 and Thy-1, was partly involved in the nursing activity. The effect of monoclonal antibodies (mAb) to these molecules depended on the incubation time and stimulation of R-TNC.1 cells. The inhibitory effect of mAb to CD2, LFA-1, CD18 and ICAM-1 on thymocyte engulfment was higher than their effect on thymocyte binding to the R-TNC.1 line. In addition, a LFA-1/CD18-dependent/ICAM-1-independent adhesion pathway was identified when unstimulated R-TNC.1 cells with minimal expression of ICAM-1 were used. The combination of inhibitory mAb did not completely abrogate the nursing activity of the R-TNC.1 line, suggesting the possible involvement of some other adhesion molecules.

Animals↗

PubMed1993

Two novel monoclonal antibodies reactive with different components of the rat thymic epithelium.

Two novel monoclonal antibodies (mAbs) (PT10B7 and PT13D11) have been raised against molecules of rat thymic epithelial cells (TEC). Streptavidin-biotin immunoperoxidase staining and double immunofluorescence using these mAbs and anti-cytokeratin (CK) antibodies showed that PT10B7 and PT13D11 mAbs bound to different components of rat TEC. PT10B7 mAb reacted with cortical and a subset of medullary TEC, whereas PT13D11 mAb labeled subcapsular/perivascular and most medullary TEC, including TE-R 2.5 TEC line of medullary origin. Their staining patterns were different from those seen using mAbs to CK10, CK18 and CK19 polypeptides and other anti-rat TEC mAbs produced so far. The differences in immunoreactivity of these two mAbs on rat thymus during ontogeny and on other epithelial cells of adult rats were also seen. Namely, PT13D11 stained ectoderm-derived epithelia, whereas PT10B7 stained some cells of simple epithelia. Cumulatively, these results reveal a fine phenotypic heterogeneity within rat thymic epithelium.

Animals↗