Biomedical subjects

M Colić

Publications and source records attributed to M Colić.

At least 37 records · Page 2Linked to original sources

PubMed1999

White Addison's disease: what is the possible cause?

A case of chronic primary adrenal insufficiency without hyperpigmentation in a 64-year-old woman is reported. Due to the absence of hyperpigmentation the diagnosis was delayed and she became critically ill. During endocrine evaluation, in order to investigate the mechanism responsible for the absence of hyperpigmentation, skin biopsy was done and hormones responsible for the skin pigmentation were measured. Absence of hyperpigmentation is explained by high degree of melanosome degradation in secondary lysosomes called "compound melanosomes", which overwhelmed increased stimulation of the skin pigmentation. Melanocyte-stimulating hormones were elevated with a strikingly high beta-LPH/ACTH ratio. To our knowledge, this is the first study of pathogenic mechanisms responsible for the absence of hyperpigmentation in white Addison's disease.

Addison Disease↗

PubMed1999

Differential effects of anti-rat CD11b monoclonal antibodies on granulocyte adhesiveness.

Four different monoclonal antibodies (mAbs) reactive with rat CD11b (ED7, ED8, OX-42 and 1B6c) have been characterized for their ability to induce homotypic aggregation of granulocytes or to modify granulocyte adhesiveness triggered by phorbol myristate acetate (PMA) or N-formyl-methionyl-leucyl-phenylalanine (fMLP). Cross-blocking experiments showed that these mAbs recognize at least three different epitopes on CD11b. OX-42 mAb recognizes an inhibitory epitope since the mAb inhibited homotypic aggregation of granulocytes and their adherence to plastic in the presence of PMA or fMLP. ED7 and ED8 induced homotypic aggregation of granulocytes which was blocked by OX-42 and anti-CD18 mAb (WT3) suggesting that CR3 itself is involved in the adhesion process. The aggregation was dependent on active cell metabolism, intact cytoskeleton, divalent cations and activation of tyrosine kinases sensitive to genistein. Staurosporine, okadaic acid and orthovanadate potentiated the aggregation. ED7 and ED8 potentiated homotypic aggregation and adhesion of granulocytes to plastic caused by fMLP, but inhibited granulocyte adhesion to plastic induced by PMA. 1B6c recognizes an epitope that transmits a proaggregatory signal upon binding of the mAb but only if the granulocytes are in contact with plastic or are activated by fMLP. In contrast, 1B6c inhibited granulocyte adhesion to plastic triggered by PMA or fMLP. These data suggest the existence of functionally different epitopes on rat CD11b and indicate that some anti-CD11b mAbs are able to functionally activate CR3.

Animals↗

PubMed1999

[Surgical management of a ruptured aneurysm of the common carotid artery--case report].

A case report on 80-year patient ruptured aneurysm of the common carotid artery (CCA), immediately below its branching which leading to pulsatile mass on the neck. Fifteen days later skin perforation and external hemorrhage ensued. The diagnosis was established by clinical examinations, ECHO duplex scan US, arteriography of carotid arteries and CT of the neck (cervical CT). The patient underwent emergency surgical procedure in general endotracheal anesthesia. The approach to the rupture site was hindered by the massive hematoma and thus CCA, ICA and ECA were trapped. Arteriotomy of ICA and CCA was performed and intraluminal shunt placed (inserted). Perforation site was managed using endoluminal Dacron patch fixating by continuous Prolen suture. Narrow Dacron patch was used for closing arteriotomy. The complete surgical procedure lasted 45 minutes. Immediate and 6-th and 12 month follow up examination were conducted (Duplex scan, carotid artery DSA) evidencing no neurological deficits or any other complications. Preoperative condition, intraoperative findings and postoperative course were clearly and thoroughly documented. The author found endoluminal patch plasty at the site of the rupture-induced defect to be simple and safe method.

Aged↗

PubMed1998

Bidirectional interactions between thymocytes and thymic epithelial cell lines in vitro.

In vitro interactions of thymocytes and thymocyte hybridomas with cortical (R-TNC.1) and medullary (TE-R 2.5) rat thymic epithelial-cell (TEC) lines were studied. It was found that the cortical line had better adhesion capability. It bound exclusively immature CD4+ CD8+ alpha beta TCRlo thymocytes, induced apoptosis of a subset of these cells, and stimulated proliferation of the BWRT 1 (CD4- CD8- alpha beta TCR-) hybridoma. The medullary line bound both immature and mature thymocytes, decreased their apoptosis, and induced apoptosis of the BWRT 8 (CD4+ CD8lo alpha beta TCRhi) hybridoma. Thymocyte differently modulated cytokine production by TEC lines, upregulating the secretion of IL-1 by R-TNC.1 and IL-6 by TE-R 2.5 cells. Finally, coculture of thymocytes with TEC lines resulted in different patterns of protein-tyrosine phosphorylation in thymocytes. These results show the existence of mutual bidirectional interactions between thymocytes and TEC lines in vitro, but these processes differed depending on phenotypic characteristics and origin of TEC lines used.

Animals↗

PubMed1997

Leptin levels and insulin sensitivity in obese and non-obese patients with polycystic ovary syndrome.

The study was conducted to assess leptin levels and insulin sensitivity in obese and non-obese patients with polycystic ovary syndrome (PCOS). Twenty-two women with PCOS and 19 control healthy women were included in the study, divided into obese and non-obese groups. Leptin was determined using Linco Research radio-immunoassay while insulin sensitivity was calculated from intravenous glucose tolerance tests with frequent blood sampling using MINMOD analysis. Significantly higher basal leptin levels were found in obese compared to non-obese PCOS (31.76 +/- 3.06 vs. 10.42 +/- 2.31 ng/ml; p < 0.05) as well as in obese in comparison to non-obese controls (29.16 +/- 5.06 vs 8.51 +/- 0.88 ng/ml; p < 0.05). A negative correlation was found between insulin sensitivity and leptin levels in both obese (r = -0.2480; p > 0.05) and non-obese PCOS groups (r = -0.4620; p > 0.05). In conclusion, high serum leptin, insulin and testosterone levels together with reduced insulin sensitivity were found in obese PCOS women, suggesting that high leptin levels could be a characteristic of the obese PCOS phenotype.

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↗

PubMed1996

Emergency treatment and early fluid resuscitation following electrical injuries.

Injuries caused by high-tension electrical current are rare, but pathophysiologically unique with destructive effects. As a form of thermal trauma, electrical injuries represent a connection of skin burns and deep tissue destruction unpredictable in its depth which mostly resembles a crush injury. Emergency treatment measures begin with the separation from the electrical contact if any and prompt transport to the nearest institution with all means for cardiorespiratory resuscitation and complete recovery. Resuscitation of the patient after electric shock continues then with fluid replacement using special formula modified for such cases, correction of acidosis and myoglobinuria and finally with escharotomy and fasciotomy which is most often necessary.

Acidosis↗

PubMed1995

Aberrant levels of cytokines within the healing wound after burn injury.

OBJECTIVE: To study the effect of a burn injury on the course of cellular and cytokine changes in a wound and the relationship of these cytokines to the amounts of protein and collagen deposited at the site of the wound. DESIGN: A randomized control trial was done in which one group of rats were subjected to a severe burn injury. With the use of a sponge matrix model, the wound-healing parameters were evaluated. MATERIALS: A random sample of eight inbred albino Oxford rats per group were used in all experiments. INTERVENTIONS: Rats were subjected to a severe scald injury. Polyvinyl sponges were used as the wound-healing model. MAIN OUTCOME MEASURE: The obtained results implied that the wound-healing process is impaired after a severe burn injury. RESULTS: The wounds in these animals with burn injuries contained a lower number and an altered type of infiltrating cells with aberrant levels of cytokines, higher levels of interleukin-6, and lower levels of tumor necrosis factor and interleukin-1 in the fluids of the wounds. The parameters of healing (amounts of protein and collagen deposited at the site of the wound) were significantly lower in animals with burn injuries on days 7 and 14. CONCLUSION: The underlying mechanism of the impaired healing of a wound after burn injury could lie in the altered migration of inflammatory cells to the site of the wound and in the aberrant cytokine levels within the wound.

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

Post-traumatic activation of draining lymph node cells. II. Proliferative and phenotypic characteristics.

Proliferative and phenotypic characteristics of cells in regional lymph nodes that drain burn injury were examined in rats on day 3 postburn, i.e. at the time of maximal spontaneous proliferation and of interleukin-2 and accessory cytokine (IL-1 and IL-6) production. The importance of IL-1 in spontaneous proliferation of draining lymph node cells was demonstrated by stimulation of IL-2-driven proliferation by recombinant IL-1 in vitro and by susceptibility of unstimulated proliferation to anti-IL-1 antibodies, while requirements for IL-6 in draining lymph node cell proliferation were less pronounced. Cell surface phenotyping revealed a slightly increased percentage of CD25+ cells in the blast cell population of freshly isolated draining lymph node cells after injury, which increased further during cultivation. Enrichment in CD8+ cells on day 3 following burn injury was demonstrated, while no changes in total cell population and CD4+ cells was noted. This was however preceded by pronounced percentual decrease of total T cells and CD4+ cells and by increases of B cells and MHC class II+ cells on day 1 postburn. Inhibition of draining lymph node cell proliferation by anti-MHC class II antibodies suggested that this proliferation was class II MHC dependent. The contribution of cell proliferation and/or cell influx to day 3 postburn draining lymph node cell activity is discussed.

Animals↗

PubMed1994

Immunocytochemical demonstration of prostaglandin synthase (cyclooxygenase) in thymic macrophages of normal and cyclosporin-treated rats.

As revealed with ED1 and ED2 monoclonal antibodies, macrophages are scattered throughout the thymic tissue. However, in contrast to the cortex and medulla, in the cortico-medullary zone macrophages are large and show strong reactivity with rabbit polyclonal antisera to cyclooxygenase. Only few smaller cortical macrophages also show weaker presence of prostaglandin synthase. After cyclosporin treatment cortical macrophages become strikingly similar to the macrophages of the cortico-medullary zone of the normal thymus. Cortical macrophages become enlarged and develop the strong expression of prostaglandin synthase. Our results show that a specific type of macrophages (with distinct histochemical characteristics, enzyme profile and ultrastructural organization, which is strategically positioned within the thymic tissue--as we demonstrated earlier) possesses the enzyme capacity required for prostaglandin synthesis. After cyclosporin treatment, which interferes with the maturation of thymocytes, cortical macrophages thoroughly change and develop the strong prostaglandin synthase expression, similar to that of normal cortico-medullary zone macrophages.

Animals↗

PubMed1994

Influence of a radioprotector WR-638 on the lymphoid compartment of the irradiated rat thymus: a flow cytometric analysis.

The T cell composition of the thymus of X-ray irradiated (3.5 Gy) Wistar rat protected with WR-638 was analyzed by flow cytometry using monoclonal antibodies directed to the Thy 1.1, CD43, CD2, CD5, CD4, CD8 and class I and II MHC antigens. It was shown that this dose of X-rays caused cyclic changes in thymic cellularity manifested as: primary involution (until day 2), primary regeneration (from days 2 to 14), secondary involution (from days 14 to 21) and secondary regeneration (from days 21 to 30). WR-638 reduced the magnitude of thymocyte depletion in the primary involutive phase of the irradiated thymi, primarily as a result of protection of Thy 1.1high+ CD2low+ CD5high+ CD4+ CD8+ class I antigen high+ subpopulations of thymocytes. In the early regenerative phase, WR-638 accelerated the regeneration of CD4-CD8- and CD4-CD8+ thymocyte subsets, followed by subsequent increase of CD4+CD8+ and CD4+CD8- thymocyte subsets. Secondary involutive and regenerative phases in protected animals were characterized by higher absolute cell number of almost all thymocyte subpopulations in comparison with those in irradiated, non-protected animals.

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↗

PubMed1993

Ultrastructural study of macrophages of the rat thymus after cyclosporin treatment.

Young adult male Wistar rats were given 30 mg per kg of cyclosporin (CS) for 21 consecutive days. After CS treatment thymic medulla virtually disappears and the thymus is almost entirely composed of cortical tissue. Macrophages are scattered throughout the thymic cortex. These cells are very large, rounded, with inconspicuous prolongations and euchromatic nucleus with prominent nucleoli. These cells are loaded with lipid bodies and vacuolar cytoplasmic inclusions of different size and diverse content, but very rarely contain phagocytosed lymphocyte remnants. The cytoplasm between inclusions has very active aspect with abundance of polyribosomes, granular endoplasmic reticulum and vesicles. Mitoses of lymphocytes in the vicinity of macrophages are frequently seen. We discuss the morphological similarity between cortical macrophages of CS-treated thymus and macrophages of cortico-medullary zone (CMZ) of the normal rat thymus, as well as functional significance of described morphological characteristics of this type of thymic macrophages, which probably reflect the metabolism of arachidonic acid.

Animals↗

PubMed1993

Phenotype and adhesion characteristics of rat thymic macrophages cultivated in serum-free medium.

Rat thymic macrophages (TMF) were cultivated in serum-free medium (Biorich 2) using an explant technique. This medium favored the growth of macrophages and inhibited the proliferation of other non-lymphoid cells. Macrophage characteristics of cultivated cells were confirmed by their morphology, NSE activity and positivity (approx. 95%) with ED1 and Mar 1 mAbs (pan-macrophage markers in the rat). The majority of non-adherent cells (NAC) released in culture medium during the proliferation of TMF also possessed macrophage characteristics. Both adherent TMF and NAC were heterogeneous cells expressing cortical/CMZ phenotype (ED2+, R-MC 41+, R-MC 42+) and CMZ/medullary phenotype (R-MC 43+, R-MC 44+). NAC population contained higher proportion of cells expressing class II MHC molecules, IL-2R and 1F119 antigen compared to adherent TMF. The TMF phenotype changed during cultivation and upon stimulation with inflammatory cytokines (IL-1, IFN-gamma, TNF-alpha). TMF formed rosettes with syngeneic or allogeneic thymocytes both at 37 and 4 degrees C. The percentages of rosettes was dependent on the incubation time and TMF/thymocyte ratio. A higher percentage of immature thymocytes (CD4-CD8- or CD4+CD8+) bound to TMF compared to mature, cortisone-resistant thymocytes. The involvement of TMF membrane molecules in TMF/thymocyte adhesion was tested by preincubation of TMF with specific mAbs. It was found that Mar 1 mAb was partially inhibitory, OX-42 (anti CD11b) was slightly stimulatory, whereas other mAbs had no significant effect.

Animals↗