Localization of peroxidase activity in blood mononuclear phagocytes in pacu fish (Piaractus mesopotamicus)

The localization of peroxidase activity in different cell regions is used as a criterion for classifying the stage of maturity of mammalian mononuclear phagocytes, with a positive peroxidase reaction indicating the presence of monoblasts, promonocytes, monocytes, and macrophages. Peroxidase activity was observed ultrastructurally in the circulating blood of pacu fish (Piaractus mesopotamicus), identifying monoblasts, promonocytes, monocytes, and macrophages. These observations suggest that differentiation of mononuclear phagocytes occurs in the blood circulation of fish, whereas in mammals, monoblasts and promonocytes are detected in bone marrow, with only monocytes detected in circulating blood and differentiation into macrophages occurring in other body compartments.

Malignant transformation of pleomorphic xanthoastrocytoma: Case report

We report a case of a pleomorphic xantoastrocytoma which manifested itself as a cystic isodense lesion in the right fronto-temporal lobe in a 26 year-old woman. It appeared as a soft yellow tumor with cystic cavities on surgery. Five months after this surgery, the patient was submitted to a new operation, which revealed a friable tumor, easily differentiated from the normal parenchyma, with cystic components. The histopathological examination demonstrated pleomorphic xanthoastrocytoma with malignant transformation. Histologically, the tumor at first procedure was composed of pleomorphic astrocytes with multinucleated and foamy cells. A rare case of malignant transformation in pleomorphic xanthoastrocytoma is presented, discussed and illustrated in this paper.

Comparative analysis of tissue reactions to anesthetic solutions: histological analysis in subcutaneous tissue of rats.

Postanesthetic pain is a relatively common complication after local anesthesia. This complication may be caused by the anesthetic technique or by the anesthetic solution used. Tissue reactions induced by the anesthetic solutions may be one of the factors resulting in pain after anesthesia. The objective of this study was to comparatively analyze tissue reactions induced by different anesthetic solutions in the subcutaneous tissue of rats. The following solutions were utilized: 2% lidocaine without vasoconstrictor; a 0.5% bupivacaine solution with 1:200,000 adrenaline; a 4% articaine solution and 2% mepivacaine, both with 1:100,000 adrenaline; and a 0.9% sodium chloride solution as a control. Sterilized absorbent paper cones packed inside polyethylene tubes were soaked in the solutions and implanted in the subcutaneous region. The sacrifice periods were 1, 2, 5, and 10 days after surgery. The specimens were prepared and stained with hematoxylin and eosin for histological analysis. The results showed that there is a difference in tissue irritability produced by the local anesthetic solutions. The results also showed that there is no relation between the concentration of the drug and the inflammatory intensity, that the mepivacaine and articaine solutions promoted less inflammatory reaction than the bupivacaine, and that the lidocaine solution produced the least intense inflammation.

Ativação de macrófagos por produtos naturais obtidos da Achillea millefolium L. (Asteraceae)

Plants are a valuable source of natural products for the maintenance of human health. The purpose of this paper was the study of immunologic activity of yarrow (Achillea millefolium L.), a largely used plant in popular medicine that has many different properties such as: antiinflammatory, astringent, antiseptic and antispasmodic. Macrophages stimulation was evaluated by the determination of H2O2, NO and TNF-α in supernatants of peritoneal macrophages cultures of mice in the presence of the yarrow leaves extract. The thin layer chromatography of extract was also analyzed, showing rutin. All concentrations showed a moderate release of H2O2 and the concentrations of 6, 8 and 10mg/mL had a higher release of NO. The TNF-a was produced in all concentrations, but the best result was obtained at 4mg/mL. Analyzing the results, it is suggested that the yarrow ethanolic extract can modulate the macrophages activation.

Secretion of tumor necrosis factor-alpha by mouse peritoneal macrophages in the presence of dental sealers, sealapex and endomethasone

After filling root canals, the healing process depends on the chemical composition or physical-chemical properties of the material used, among other factors. All root canal sealers, whether solid or plastic, are foreign matter for the body if they remain in permanent contact with apical and periapical tissues. As a result, the first organic reaction that occurs is an attempt to phagocytize the material. During phagocytosis, macrophages release a large number of cell mediators into the area, among which are cytokines that are essential in intercellular communication and in many physiological and pathophysiological processes. One of these cytokines is tumor necrosis factor-alfa (TNF-α), which acts through links to specific receptors on the cell membrane initiating a cascade of events leading to induction, activation, or inhibition of numerous cytokine-regulated genes in the cell nucleus. The release of TNF-α in a cell culture of mouse peritoneal macrophages incubated with three concentrations (25, 50, and 100 mg/ml) of two endodontic sealers was measured. The solutions containing the calcium hydroxide-based root canal sealer (Sealapex) released fewer units of TNF-α than solutions containing the zinc oxide and eugenol-based sealer (Endomethasone).

Acellular dermal tissue study: an ultrastructural evaluation of human and porcine derived tissues in a rat model

The purpose of this study was to evaluate the host response of a human and a porcine derived acellular dermal tissue (ADT) implanted in the subcutaneous tissue of a rat model. Two subcutaneous pockets were surgically created along the dorsal midline of 25 rats (5 rats/group). The human ADT was placed superiorly and the porcine ADT, inferiorly. The animals were sacrificed at 07, 15, 30, 60 and 180 postoperative days (PO) and the ADTs and surrounding soft tissues were assessed for ultrastructural evaluation by transmission electron microscopy. The ultrastructural findings were similar in both materials. Normal collagen and elastic fibers bundles were observed during all experimental moments, as well as macrophages presenting cytoplasmic enlargements digesting cellular portions after 15 PO. From 30 until 180 PO, vacuolar structures filled with an amorphous, electron-transparent substance, were present inside and outside the fibroblasts. Both human and porcine ADT showed similar pattern of ultrastructural response when implanted in the subcutaneous tissue of rats. The porcine ADT appears as a good alternative to be used as a biomaterial.

Interação das enterotoxinas estafilocócicas com o sistema imune do hospedeiro

Staphylococcal enterotoxins are among the most common etiologic agents that cause food poisoning and, possibly, nonmenstrual toxic shock syndrome. These enterotoxins are also called superantigens because they are potent T cell and macrophages activators. The superantigens bind directly to the major histocompatibility complex class II molecules on antigen-presenting cells and stimulate T cells expressing specific Vβ elements in the cell receptors. Excessive production of cytokines by these cells and macrophages are responsible for the pathogenesis of food poisoning. These cytokine include tumor necrosis factor (TNF)-α, interferon (IFN)-γ and interleukin (IL)-1, proinflamatory mediators with potent immunoenhancing effects; the nitric oxide (NO). It still has both effects citotoxic and regulatory roles in immune function.

Citotoxicidade de Styrax camporum Pohl em macrófagos peritoneais e a liberação de H2O2

The immunological response includes wide contexts involving several cells, and the macrophage is crucial in the cellular immune response. Several stimuli to macrophage membrane may induce the liberation of H2O2, contributing to antibacterial and cytotoxicical actions. Nowadays, there is a tendency to study natural products to verify their capacity of acting in the immune system. This study evaluated the citotoxicity of the bulk extract and the hexanic and acetic fractions extracted from Styrax camporum Pohl (Styracaceae) and the production of H2O2, on murine peritonal macrophages cultures exposed to fractions extracted from this plant. The results showed that the fraction HX 2 mg/ml produced the liberation of H 2O2 in high concentrations and to 4 mg/ml was observed high citotoxicity. The fractions AC did not produce the liberation of H 2O2 and EB was produced in low levels. We conclude that this HX is a potent stimulator of macrophage.

Critical protective role for annexin 1 gene expression in the endotoxemic murine microcirculation

The inflammatory response is a protective process of the body to counteract xenobiotic penetration and injury, although in disease this response can become deregulated. There are endogenous biochemical pathways that operate in the host to keep inflammation under control. Here we demonstrate that the counter-regulator annexin 1 (AnxA1) is critical for controlling experimental endotoxemia. Lipopolysaccharide (LPS) markedly activated the AnxA1 gene in epithelial cells, neutrophils, and peritoneal, mesenteric, and alveolar macrophages-cell types known to function in experimental endotoxemia. Administration of LPS to AnxA1-deficient mice produced a toxic response characterized by organ injury and lethality within 48 hours, a phenotype rescued by exogenous application of low doses of the protein. In the absence of AnxA1, LPS generated a deregulated cellular and cytokine response with a marked degree of leukocyte adhesion in the microcirculation. Analysis of LPS receptor expression in AnxA1-null macrophages indicated an aberrant expression of Toll-like receptor 4. In conclusion, this study has detailed cellular and biochemical alterations associated with AnxA1 gene deletion and highlighted the impact of this protective circuit for the correct functioning of the homeostatic response to sublethal doses of LPS. Copyright © American Society for Investigative Pathology.

The β-chemokines MIP-1α and RANTES and lipoprotein metabolism in HIV-infected Brazilian patients

HIV patients are predisposed to the development of hypertriglyceridemia and hypercholesterolemia as a result of both viral infection and HIV infection therapy, especially the protease inhibitors. Chemokines and cytokines are present at sites of inflammation and can influence the nature of the inflammatory response in atherosclerosis. We investigated the correlation between biochemical variables and β-chemokines (MIP-1α and RANTES) and the apolipoprotein E genotype in HIV-infected individuals. The apolipoproteins were measured by nephelometry. Triglycerides and total cholesterol were determined by standard enzymatic procedures. The β-chemokines were detected by ELISA. The genetic category of CCR5 and apolipoprotein E were determined by PCR amplification and restriction enzymes. Immunological and virological profiles were assessed by TCD4 + and TCD8 + lymphocyte counts and viral load quantification. Positive correlations were found between apo E and CD8 + (p = 0.035), apo E and viral load (p = 0.018), MIP-1α and triglycerides (p = 0.039) and MIP-1α and VLDL (p = 0.040). Negative correlations were found between viral load and CD4 + (p = 0.05) and RANTES and CD4 + (p = 0.029). The β-chemokine levels may influence lipid metabolism in HIV-infected individuals. © 2005 by The Brazilian Journal of Infectious Diseases and Contexto Publishing. All rights reserved.

Immune Response to the Rhodococcus equi infection in high and low antibody-producing mice (selection IV-A)

Rhodococcus equi is a Gram-positive, facultative intracellular bacterium which infects macrophages and causes rhodococcal pneumonia and enteritis in foals. Recently, this agent has been recognized as an opportunistic pathogen for immunocompromised humans. Several murine experimental models have been used to study R. equi infection. High (H IV-A) and Low (L IV-A) antibody (Ab)-producers mice were obtained by bi-directional genetic selections for their ability to produce antibodies against sheep and human erythrocytes (Selection IV-A). These lines maintain their phenotypes of high and low responders also for other antigens than those of selection (multispeciflc effect). A higher macrophage activity in L IV-A mice has been described for several intracellular infectious agents, which could be responsible for their intense macrophage antigens (Ag)-handling and low Ab production. Due to these differences, L IV-A mice were found to exhibit a better performance to trigger an effective immune response towards intracellular pathogens. The objective of this work was to characterize the immune response of Selection IV-A against R. equi. H IV-A and L IV-A mice were infected with 2.0 × 10 6 CFU of ATCC 33701 +R. equi by intravenous route. With regards to bacterial clearance and survival assays, L IV-A mice were more resistant than H IV-A mice to virulent R. equi. L IV-A mice presented a higher hydrogen peroxide (H 2O 2) and nitric oxide (NO) endogenous production by splenic macrophages than H IV-A mice. L IV-A expressed the most intense cellular response, available by the Delayed-Type Hypersensitivity (DTH) reaction, which activated macrophages and produced more H 2O 2 and NO. The three times higher specific antibodies titres in H IV-A indicated that Selection IV-A maintained the multispecific effect and the polygenic control of humoral and cellular responses also to R. equi.

Morphological, cytochemical, and ultrastructural study of thrombocytes and leukocytes in neotropical fish, Brycon orbignyanus Valenciennes, 1850 (Characidae, Bryconinae)

Morphological, cytochemical and ultrastructural studies are important to demonstrate the function of the blood cells, which is very little understood in teleosts. In peripheral blood of piracanjuba' Brycon orbignyanus, thrombocytes, lymphocytes, monocytes, neutrophils and heterophils were studied and characterized. Thrombocytes had a fusiform or oval shape with PAS-positive granules. Lymphocytes presented small size with sparse basophilic cytoplasm. Monocytes were large in size, presented basophilic cytoplasm that may be foamy or vacuolated, with non-specific esterase staining. The neutrophils presented lightly neutrophilic granule cytoplasm, with positivity for PAS and peroxidase. The heterophils were large in size, with eosinophilic and basophilic granules cytoplasm and PAS-positive. Transmission electron microscopy study demonstrated that the thrombocytes, lymphocytes and monocytes features were similar to other teleosts. In ultrastructural study only one type of neutrophils was observed. Cytochemical findings indicated that neutrophils and monocytes of B. orbignyanus may be involved in phagocytosis, and neutrophils play an important microbicidal role.

In situ expression of mononuclear cell markers and interleukin-2 receptor in renal allograft biopsies of acute rejection and borderline cases

The correct diagnosis of renal allograft rejection may be difficult using only clinical and/or histopathological criteria. Immunological assays should be considered in order to evaluate the phenotype of inflammatory infiltrate in renal allograft biopsies. Immunohistochemical studies were performed to detect mononuclear cells, CD4 and CD8 T lymphocytes, B lymphocytes, macrophages, null cells, and positive cells for interleukin-2 receptors. A total of 41 allograft biopsies classified into three groups were studied: acute cellular rejection (28 biopsies/22 patients), borderline (7 biopsies/5 patients) and control (6 biopsies/6 patients). In the rejection group (RG), increased cellularity was found mainly at the tubulo-interstitial level. Expression of CD8 positive cells was higher in RG when compared to borderline (BG) and control (CG) groups, respectively (0.9 vs. 0.0 vs. 0.35 cells/mm2; p < 0.001). Expression of macrophages was not statistically significant among the three groups (RG = 0.6 vs. BG = 0.2 vs. CG = 0.0 cells/mm2; p < 0.02). In the BG, CD4 + cells predominated (BG = 0.2 vs. RG = 0.05 vs. CG = 0.0 cells/mm2; p < 0.05). Clinically these patients were treated as cases of acute rejection. The numbers and different types of infiltrating cells did not correlate with patient's clinical outcome. Copyright © Informa Healthcare.

The effect of CpG-ODN on antigen presenting cells of the foal

Background: Cytosine-phosphate-guanosine oligodeoxynucleotide (CpG-ODN) has been used successfully to induce immune responses against viral and intracellular organisms in mammals. The main objective of this study was to test the effect of CpG-ODN on antigen presenting cells of young foals. Methods: Peripheral blood monocytes of foals (n = 7) were isolated in the first day of life and monthly thereafter up to 3 months of life. Adult horse (n = 7) monocytes were isolated and tested once for comparison. Isolated monocytes were stimulated with IL-4 and GM-CSF (to obtain dendritic cells, DC) or not stimulated (to obtain macrophages). Macrophages and DCs were stimulated for 14-16 hours with either CpG-ODN, LPS or not stimulated. The stimulated and non-stimulated cells were tested for cell surface markers (CD86 and MHC class II) using flow cytometry, mRNA expression of cytokines (IL-12, IFNα, IL-10) and TLR-9 using real time quantitative RT-PCR, and for the activation of the transcription factor NF-κB p65 using a chemiluminescence assay. Results: The median fluorescence of the MHC class II molecule in non-stimulated foal macrophages and DCs at birth were 12.5 times and 11.2 times inferior, respectively, than adult horse cells (p = 0.009). That difference subsided at 3 months of life (p = 0.3). The expression of the CD86 co-stimulatory molecule was comparable in adult horse and foal macrophages and DCs, independent of treatment. CpG-ODN stimulation induced IL-12p40 (53 times) and IFNα (23 times) mRNA expression in CpG-ODN-treated adult horse DCs (p = 0.078), but not macrophages, in comparison to non-stimulated cells. In contrast, foal APCs did not respond to CpG-ODN stimulation with increased cytokine mRNA expression up to 3 months of age. TLR-9 mRNA expression and NF-kB activation (NF-kB p65) in foal DCs and macrophages were comparable (p > 0.05) to adult horse cells. Conclusion: CpG-ODN treatment did not induce specific maturation and cytokine expression in foal macrophages and DCs. Nevertheless, adult horse DCs, but not macrophages, increased their expression of IL-12 and IFNα cytokines upon CpG-ODN stimulation. Importantly, foals presented an age-dependent limitation in the expression of MHC class II in macrophages and DCs, independent of treatment. © 2007 Flaminio et al; licensee BioMed Central Ltd.