Cone beam computed tomography assessment of the pterygomaxillary region and palatine canal for Le Fort I osteotomy.

The aim of this study was to evaluate the anatomical linear measurements of the descending palatine canal and the pterygomaxillary fissure for Le Fort I preoperative planning. Seventy-five patients, comprising 46 females (61.3%) and 29 males (39.7%), underwent multi-slice computed tomography examinations performed for preoperative orthognathic surgical planning. The images were categorized according to sex, craniofacial side, and skeletal and craniofacial patterns. The anterior length between the descending palatine canal and the lateral wall of the piriform rim showed a higher mean value for males compared to females (P=0.0121). The posterior distance also showed a difference between the sexes and the highest mean was observed in females (P=0.0295). Comparing the posterior width for the skeletal patterns, a statistical difference was observed between classes I and III (P=0.0371), and classes II and III (P=0.0094). Regarding the craniofacial patterns, the brachycephalic (P=0.0078) and mesocephalic (P=0.0015) groups showed a greater posterior width in females. In conclusion, the patient's sex and aspects of the skeletal pattern and craniofacial pattern have an influence on the pterygomaxillary area and descending palatine canal anatomy. A preoperative computed tomography analysis involving this evaluation could reduce the risk of surgical complications.

The left lung is preferentially targeted during experimental paracoccidioidomycosis in C57BL/6 mice.

Paracoccidioidomycosis (PCM) is a chronic systemic mycosis caused by the inhalation of the thermally dimorphic fungus Paracoccidioides brasiliensis as well as the recently described P. lutzii. Because the primary infection occurs in the lungs, we investigated the differential involvement of the right and left lungs in experimental P. brasiliensis infection. Lungs were collected from C57BL/6 mice at 70 days after intravenous infection with 1×106 yeast cells of a virulent strain of P. brasiliensis (Pb18). The left lung, which in mice is smaller and has fewer lobes than the right lung, yielded increased fungal recovery associated with a predominant interleukin-4 response and diminished synthesis of interferon-γ and nitric oxide compared with the right lung. Our data indicate differential involvement of the right and left lungs during experimental PCM. This knowledge emphasizes the need for an accurate, standardized protocol for tissue collection during studies of experimental P. brasiliensis infection, since experiments using the same lungs favor the collection of comparable data among different mice.

The left lung is preferentially targeted during experimental paracoccidioidomycosis in C57BL/6 mice

Paracoccidioidomycosis (PCM) is a chronic systemic mycosis caused by the inhalation of the thermally dimorphic fungus Paracoccidioides brasiliensis as well as the recently described P. lutzii. Because the primary infection occurs in the lungs, we investigated the differential involvement of the right and left lungs in experimental P. brasiliensis infection. Lungs were collected from C57BL/6 mice at 70 days after intravenous infection with 1×106 yeast cells of a virulent strain of P. brasiliensis (Pb18). The left lung, which in mice is smaller and has fewer lobes than the right lung, yielded increased fungal recovery associated with a predominant interleukin-4 response and diminished synthesis of interferon-γ and nitric oxide compared with the right lung. Our data indicate differential involvement of the right and left lungs during experimental PCM. This knowledge emphasizes the need for an accurate, standardized protocol for tissue collection during studies of experimental P. brasiliensis infection, since experiments using the same lungs favor the collection of comparable data among different mice.

B cell-deficient mice display enhanced susceptibility to Paracoccidioides brasiliensis Infection.

Paracoccidioidomycosis (PCM) is a chronic granulomatous disease caused by the thermally dimorphic fungus Paracoccidioides brasiliensis. T helper 1 (Th1)-mediated immunity is primarily responsible for acquired resistance during P. brasiliensis infection. On the contrary, the susceptibility is associated with occurrence of type-2 immunity (Th2), which is characterized by IL-4 release, B cell activation, and production of antibodies. Although antibodies are frequently associated with severe PCM, it is not clear whether they contribute to susceptibility or merely constitute a marker of infection stage. Here, we assessed the function of B cells during experimental P. brasiliensis infection in mice, and our results showed that B cell-knockout (B(KO)) mice are more susceptible than their wild-type littermate controls (C57BL/6, WT). The B(KO) mice showed higher mortality rate, increased number of colony-forming units in the lungs, and larger granulomas than WT mice. In the absence of B cells, we observed high levels of IL-10, whereas IFN-γ, TNF-α, and IL-4 levels were similar between both groups. Finally, we showed that transference of WT immune serum to B(KO) mice resulted in diminished infiltration of inflammatory cells and better organization of the pulmonary granulomas. Taken together, these data suggest that B cells are effectively involved in the control of P. brasiliensis growth and organization of the granulomatous lesions observed during the experimental PCM.

Evidence of the presence of T helper type 17 cells in chronic lesions of human periodontal disease.

INTRODUCTION: Periodontal disease is a chronic inflammation of the attachment structures of the teeth, triggered by potentially hazardous microorganisms and the consequent immune-inflammatory responses. In humans, the T helper type 17 (Th17) lineage, characterized by interleukin-17 (IL-17) production, develops under transforming growth factor-beta (TGF-beta), IL-1beta, and IL-6 signaling, while its pool is maintained by IL-23. Although this subset of cells has been implicated in various autoimmune, inflammatory, and bone-destructive conditions, the exact role of T lymphocytes in chronic periodontitis is still controversial. Therefore, in this study we investigated the presence of Th17 cells in human periodontal disease. METHODS: Gingival and alveolar bone samples from healthy patients and patients with chronic periodontitis were collected and used for the subsequent assays. The messenger RNA expression for the cytokines IL-17, TGF-beta, IL-1beta, IL-6, and IL-23 in gingiva or IL-17 and receptor activator for nuclear factor-kappaB ligand in alveolar bone was evaluated by real-time polymerase chain reaction. The production of IL-17, TGF-beta, IL-1beta, IL-6, and IL-23 proteins was evaluated by immunohistochemistry and the presence of Th17 cells in the inflamed gingiva was confirmed by immunofluorescence confocal microscopy for CD4 and IL-17 colocalization. RESULTS: Our data demonstrated elevated levels of IL-17, TGF-beta, IL-1beta, IL-6, and IL-23 messenger RNA and protein in diseased tissues as well as the presence of Th17 cells in gingiva from patients with periodontitis. Moreover, IL-17 and the bone resorption factor RANKL were abundantly expressed in the alveolar bone of diseased patients, in contrast to low detection in controls. CONCLUSION: These results provided strong evidence for the presence of Th17 cells in the sites of chronic inflammation in human periodontal disease.

B cells are involved in the modulation of pathogenic gut immune response in food-allergic enteropathy.

Food enteropathies involve uncontrolled or hypersensitivity reactions to ingested nutrients and may result in IgE and T-helper type 2 (Th2) responses as in food allergy. However, the precise role of B cells in the development of food enteropathies remains uncertain. In this work, we used B cell-deficient mice (B KO) and a model of peanut sensitization to examine the involvement of B lymphocytes in the pathogenesis of food allergy. Results showed that priming of wild-type (WT) mice with peanut proteins induced specific IgG1 and IgE responses in serum, with edema, tissue destruction, epithelial exulceration and inflammatory infiltrate in the gut of sensitized and challenged (S + Peanut) WT animals. In contrast, there was no sera immunoglobulin detection and absence of tissue destruction in the gut of B KO mice, which presented moderate inflammatory infiltrate and villous enlargement after peanut challenge. These animals presented marked decrease in IL-4 and TNF-alpha and high levels of IL-10, TGF-beta, IL-12p40 and IFN-gamma mRNA in the gut. Moreover, the expression of CCL5, CCL11 and CXCL1 was reduced in the gut of B KO mice, in contrast to elevated messages of CCL2 or similar detection of Th1-related chemokines in S + Peanut WT mice. Finally, we provided evidence that B cells are necessary to the development of food-related enteropathies and induction of gut inflammation during allergic reactions to food.

Biofilm on the apical region of roots in primary teeth with vital and necrotic pulps with or without radiographically evident apical pathosis.

AIM: To evaluate, by scanning electron microscopy (SEM), the presence of biofilms on the external surfaces of the apical third of roots of human primary teeth with vital or necrotic pulps with and without radiographically evident periradicular pathosis. METHODOLOGY: Eighteen teeth were selected: group I - normal pulp (n = 5), group II - pulp necrosis without radiographic evidence of periapical pathosis (n = 7) and group III - pulp necrosis with well-defined radiographic periapical pathosis (n = 6). After extraction, the teeth were washed with saline and immersed in 0.03 g mL(-1) trypsin solution for 20 min. The teeth were then washed in sodium cacodilate buffer and stored in receptacles containing modified Karnovsky solution. The teeth were sectioned, dehydrated in an ethanol series, critical-point dried with CO(2), sputter coated with gold and the external root surface in the apical third examined by SEM. RESULTS: In the teeth of groups I and II, the apical root surfaces were covered by collagen fibres, with no evidence of bacteria (100%). In the teeth of group III, the root apices had no collagen fibres but revealed resorptive areas containing microorganisms (cocci, bacilli, filaments and spirochetes) in all cases (100%). CONCLUSION: Microorganisms organized as biofilms on the external root surface (extraradicular infection) were detected in primary teeth with pulp necrosis and radiographically visible periapical pathosis.

Acute chagasic myocardiopathy after orthotopic liver transplantation with donor and recipient serologically negative for Trypanosoma cruzi: a case report.

Chagas disease (American trypanosomiasis) is caused by the protozoan parasite Trypanosoma cruzi. Chagas disease following solid-organ transplantation has occurred in Latin America. This report presents the occurrence of Chagas disease despite negative serological tests in both the donor and the recipient, as well as the effectiveness of treatment. A 21-year-old woman from the state of Sao Paulo (Brazil) underwent cadaveric donor liver transplantation in November 2005, due to cirrhosis of autoimmune etiology. Ten months after liver transplantation, she developed signs and symptoms of congestive heart failure (New York Heart Association functional class IV). The echocardiogram, which was normal preoperatively, showed dilated cardiac chambers, depressed left ventricular systolic function (ejection fraction = 35%) and moderate pulmonary hypertension. Clinical investigation discarded ischemic heart disease and autoimmune and other causes for heart failure. Immuno fluorescence (immunoglobulin M and immunoglobulin G) and hemagglutination tests for T cruzi were positive, and abundant T cruzi amastigotes were readily identified in myocardial biopsy specimens. Treatment with benznidazole for 2 months yielded an excellent clinical response. At the moment of submission, the patient remains in functional class I. This case highlighted that more appropriate screening for T cruzi infection is mandatory in potential donors and recipients of solid-organ transplants in regions where Chagas disease is prevalent. Moreover, it stressed that this diagnosis should always be considered in recipients who develop cardiac complications, since negative serological tests do not completely discard the possibility of disease transmission and since good results can be achieved with prompt trypanocidal therapy.

Modulation of mucosal immunity in a murine model of food-induced intestinal inflammation.

BACKGROUND: Hypersensitivity or uncontrolled responses against dietary antigens can lead to inflammatory disorders like food allergy and current models reflect a variety of causes but do not reveal the detailed modulation of gut immunity in response to food antigens after breakdown in mucosal tolerance. OBJECTIVE: To develop and characterize a murine model for food-induced intestinal inflammation and to demonstrate the modulation of gut immune response by dietary allergenic antigens. METHODS: C57BL/6 mice were sensitized with peanut proteins, challenged with peanut seeds and their sera and gut segments were collected for subsequent analyses. RESULTS: Sensitization and challenged with peanut seeds led to alterations in gut architecture with inflammatory response characterized by oedema in lamina propria and cell infiltrate composed mainly by eosinophils, mast cells, phagocytes, natural killer and plasma cells, together with low percentage of gammadelta+ and CD4+CD25+Foxp3+ cells in Peyer's patches. These animals also presented high levels of specific IgE and IgG1 in sera and modulation of mucosal immunity was mediated by increased expression of GATA-3, IL-4, IL-13 and TNF-alpha in contrast to low IFN-gamma in the gut. CONCLUSION: A murine model for food-induced intestinal inflammation was characterized in which modulation of gut immunity occurs by peanut antigens in consequence of T-helper type 2 (Th2) allergic response and failure of regulatory mechanisms necessary for mucosa homeostasis, resembling food allergy. This work shed some light on the understanding of the pathogenesis of gastrointestinal disorders and intolerance in the gut and supports the development of therapies for food-related enteropathies like food allergy, focusing on gut-specific immune response.

Peroxynitrite mediates the failure of neutrophil migration in severe polymicrobial sepsis in mice.

BACKGROUND AND PURPOSE: Sepsis is a systemic inflammatory response resulting from the inability of the host to restrict local infection. The failure of neutrophil migration to the infection site is one of the mechanisms involved in this process. Recently, it was demonstrated that this event is mediated by nitric oxide (NO). The present study addresses the possibility that peroxynitrite (ONOO(-)), a NO-derived powerful oxidizing and nitrating compound, could also be involved in neutrophil migration failure. EXPERIMENTAL APPROACH: Male C57Bl/6 mice were subjected to moderate (MSI) or severe (SSI) septic injury, both induced by cecal ligation and puncture (CLP). The leukocyte rolling and adhesion in the mesentery was evaluated by intravital microscopy. Cytokines (TNF-alpha and MIP-1alpha) were measured by ELISA and 3-nitrotyrosine (3-NT) by immunofluorescence. KEY RESULTS: Compared with saline pretreatment of SSI mice, pre-treatment with uric acid, a ONOO(-) scavenger, partially restored the failure of neutrophil rolling, adhesion and migration to the site of infection. These mice also presented low circulating bacterial counts and diminished systemic inflammatory response. Pretreatment with uric acid reduced 3-NT labelling in leukocytes in mesenteric tissues and in neutrophils obtained from peritoneal exudates. Finally, uric acid pretreatment enhanced significantly the survival rate in the SSI mice. Similarly, treatment with FeTPPs, a more specific ONOO(-) scavenger, re-established neutrophil migration and increased mice survival rate. CONCLUSIONS AND IMPLICATIONS: These results indicate that ONOO(-) contributed to the reduction of neutrophil/endothelium interaction and the consequent failure of neutrophil migration into infection foci and hence susceptibility to severe sepsis.

Morphometric analysis of experimentally induced periapical lesions: radiographic vs histopathological findings.

OBJECTIVES: To evaluate the accuracy and reliability of conventional (Kodak Ektaspeed Plus film) and digitized radiographic images to detect the presence as well to estimate the size, as measured by an image analysis programme, of periapical radiolucencies induced in dog teeth in comparison with the histomorphometric data obtained from the same lesions by conventional and fluorescence microscopy. METHOD: After the removal of pulp, the root canals of five premolars from the same animal were left exposed for 7 days after which they were sealed for 60 days. At day 53, three more premolars were opened and left exposed to the oral cavity for 7 days. Intact premolars were used as control. Conventional radiographs were taken at day 0, day 7, day 30, day 45 and day 60. Morphometry in digitized radiographic images and histological sections were compared at day 7 and day 60 after setting the experimental series. RESULTS: Radiographically, periapical lesions were only detected 30 days after coronal sealing. A progressively increasing radiolucent lesion area was observed at day 45 and day 60. Histopathologically, 7 days after pulp removal dense inflammatory infiltrate and root resorption in the periapical region was observed. At day 7 and day 60, the lesion sizes were similar when evaluated by both conventional and fluorescence microscopy. Lesion size was about 20% larger in digitized radiographs in comparison with histological measurements. CONCLUSIONS: Although image digitization could not improve the detection of the early stages of periapical lesions, it provides a valuable quantitative assessment of extensive periapical lesions. In addition, fluorescence light microscopy enhances the visualization of the apical and periapical structures and seems to be a highly useful tool for histological evaluation, valuable for both qualitative and quantitative studies of periapical disease.

Mitochondrial damage as an early event of monensin-induced cell injury in cultured fibroblasts L929.

The present study was designed to identify, submicroscopically, the primary organelle or target structure for monensin in cultured murine fibroblasts L929. In addition, the effect of the drug on cell size and surface membranes of the cells were analysed; cellular proliferation, collagen secretion, and necrosis and apoptosis were re-evaluated. At the lowest concentration of monensin the foremost ultrastructural alteration occurred in the mitochondria, characterized by increased matrix density with disorganized and less distinct crystae. Incubation with monensin at higher concentrations resulted in severe mitochondrial damage and marked dilatation of the Golgi apparatus and rough endoplasmic reticulum cisternae. Fibroblasts exposed to higher concentrations of monensin were enlarged with decreased number of filopodia and hollows in the surface membrane. Moreover, monensin inhibited the cell proliferation, increased immunohistochemical positiveness for collagen type I in a dose-dependent manner, and, at high concentrations, caused cell necrosis whereas apoptosis was not induced. Taken together, these results show that monensin induces early mitochondrial damage, possibly causing an energy deficit that led to inhibition of fibroblasts proliferation and accumulation of collagen causing dilatation of Golgi apparatus and rough endoplasmic reticulum. Moreover, the mitochondrial damage would also explain the monensin-induced necrosis.

Spatial memory in aged rats is related to PKCgamma-dependent G-protein coupling of the M1 receptor.

In the present study, individual differences in spatial memory in aged Fischer 344 (F344) rats were associated with the extent of G-protein coupling of the M1 muscarinic receptor and the dendritic-to-somal ratio of hippocampal PKCgamma (d/sPKCgamma) immunogenicity. Following testing in the eight-arm radial maze task, 7 young and 13 aged rat brains were sectioned through the dorsal hippocampal formation (HF). G-protein coupling of the M1 receptor was assessed autoradiographically using competition binding studies in the presence and absence of a G-protein uncoupler to determine high (K(H)) and low (K(L)) affinity states for agonist in the HF, neocortex, and amygdala. In aged animals, a relationship between choice accuracy in the maze and K(H), a measure of M1 receptor-G-protein coupling was seen in the dentate gyrus, CA3, CA1, and neocortex. Furthermore, choice accuracy and d/sPKCgamma immunogenicity showed a significant relationship in CA1. Lastly, a correlation was seen in the CA1 of aged animals between K(H) and d/sPKCgamma. These relationships did not hold for the amygdala. Thus, individual differences in a naturally occurring age-dependent disruption of cholinergic-PKCgamma signal transduction is associated with spatial memory dysfunction.

Characterization of a bovine collagen-hydroxyapatite composite scaffold for bone tissue engineering.

Different biomaterials have been used as scaffolds for bone tissue engineering. Here we characterize a biomaterial composed of sintered (1100 degrees C) and powdered hydroxyapatite (HA) and type I collagen (Coll), both of bovine origin, designed for osteoconductive and osteoinductive scaffolds. Coll/HA proportions were 1/2.6 and 1/1 (wet weight), and particles sizes varied from 200 to 400 microm. Vv (volume density) and Sv (surface to volume density) for the HA particles in the composite ranged from 0.48 +/- 0.06 to 0.55 +/- 0.02 and 5.090 +/- 0.545 to 6.366 +/- 0.289 microm(-1), respectively. Due to the relatively small changes in Vv and Sv, a macroporosity could be characterized for the biocomposite. X-ray diffraction and infrared spectroscopy showed that the sintered bone was composed essentially of HA with minimum additional groups such as surface calcium hydroxide, surface and crystal water, free carbon dioxide and possibly brushite. Mass spectrometry detected carbonates at A and B sites of HA, and weakly bound to the structure. Human osteoblasts adhered and spread on both the HA particle surface and the collagen fibers, which seemed to guide cells between adjacent particles. The biocomposite studied has several characteristics considered as ideal for its use as a scaffold for osteoconduction and osteoinduction.

Scanning electron microscopic study of the cleaning ability of chlorhexidine as a root-canal irrigant.

AIM: To evaluate in vitro the cleaning of root-canal walls after irrigation with different irrigants. METHODOLOGY: A total of 36 recently extracted human teeth were divided into four experimental groups according to the irrigating solution used: saline; 2% chlorhexidine; 2.5% sodium hypochlorite; and 2.5% sodium hypochlorite + EDTA. The cleaning of the apical, middle and coronal thirds of the root canals was evaluated by scanning electron microscope examination using a 4-point scoring system. RESULTS: The best cleaning was obtained using 2.5% sodium hypochlorite and EDTA, followed by 2.5% sodium hypochlorite only (P < 0.05), whose cleaning was similar to chlorhexidine only in the cervical third. Cleaning by saline and 2% chlorhexidine was worse than the other two groups and was similar in all thirds. Better cleaning was found in the cervical and middle thirds for all groups with the worst results in the apical third. CONCLUSIONS: The apical third of the root canals was not cleaned as well as the middle and coronal thirds. Cleaning by chlorhexidine and saline was inferior compared to the cleaning by sodium hypochlorite with and without EDTA.

Chronic inhibition of NO synthesis per se promotes structural intimal remodeling of the rat aorta.

OBJECTIVE: We characterized, using histomorphometry and transmission and scanning electron microscopy, the intimal remodeling of the thoracic aorta of normocholesterolemic young rats chronically-treated with N(omega)-nitro-L-arginine methylester (L-NAME) and examined the question whether these changes were caused by the lack of NO per se or by the hypertension which L-NAME administration induces. METHODS: Male Wistar rats were divided randomly into three sets: control group, standard diet/L-NAME-treated group, and standard diet/L-NAME + captopril-treated group. RESULTS: The treatment of rats with L-NAME for 4 weeks resulted in increased blood pressure (by 32% at the end of the treatment) as compared with the control value and intimal remodeling comprising a continuous layer of enlarged endothelial cells with irregular nuclear and cytoplasmic contours, lying over a thickened layer of fibrocollagenous support tissue focally expanded with lymphomononuclear cells and mainly diffuse foci of smooth muscle cells. In addition, the NO synthase inhibition caused a marked thickened tunica intima (150% thicker than the control value) and a significantly augmented intima : media ratio (126% higher than the control value). On the other hand, captopril prevented hypertension in rats simultaneously treated with L-NAME as compared with controls, and induced intimal remodeling comprising the same qualitative changes as those observed in L-NAME-treated rats. The tunica intima of l-NAME + captopril-treated rats was moderately thickened (60% increase in comparison with that of controls and 65% thinner as compared with L-NAME-treated rats). In the same way, the mean intima : media ratio of rats concomitantly treated with L-NAME and captopril was moderately increased (45% more) as compared with controls and significantly lower in comparison with rats administered L-NAME alone (36% less). CONCLUSIONS: Chronic inhibition of NO synthesis per se promotes structural intimal remodeling of the rat aorta, which is potentiated by L-NAME-induced hypertension. Most important, the present findings favor the idea that blockade of NO synthesis by causing intimal remodeling might be a primary cause, as individual biologic phenomenon, in the development of an atherosclerotic plaque.

Experimental studies on the mechanism of phospholipase C activation by the lipid peroxidation products 4-hydroxynonenal and 2-nonenal.

The effects of three lipid peroxidation end-products, 4-hydroxynonenal (HNE), 2-nonenal (NE) and nonanal, on phosphoinositide-specific phospholipase C (PL-C) activity were studied in HL-60 cells. Enzymatic activity was determined by measuring the amounts of inositol-P3 (Ins-P3) produced by the cells incubated at 37 degrees C in the presence of the various compounds. HNE was shown to activate PL-C at concentrations of between 10(-8) and 10(-6) M; 10(-9) and 10(-8) M of NE also strongly stimulated PL-C. In contrast, nonanal failed to modify enzymatic activity. The concentrations of HNE and NE active on PL-C showed good correspondence with those that have been reported to be chemotactic towards rat neutrophils. The pretreatment of cells with 1 microM pertussis toxin completely prevented the increase of Ins-P3 production induced by HNE and NE. Maximal PL-C stimulation was produced by 10 nM NE; the degree of inositol-P3 production induced by the simultaneous addition of an equimolar dose of HNE was not significantly different from the activity value induced by NE alone, suggesting a possible competition between the two compounds. The data indicate that both HNE and NE share a common mechanism of action which, as with other better-known chemoattractants, involves PL-C activation through a G regulatory protein.

Connective tissue skeleton in the normal left ventricle and in hypertensive left ventricular hypertrophy and chronic chagasic myocarditis.

Pictures certainly are worth a thousand words in the case of the structure of the connective tissue skeleton of normal and diseased myocardium. This report reviews the connective tissue matrix of the normal human myocardial tissue and the pathological myocardial fibrosis in left ventricular hypertrophy due to chronic arterial hypertension in humans and in human chronic chagasic myocarditis. The myocardial connective tissue matrix was studied employing a cell-maceration method that removes the myocardial tissue non-fibrous elements, and leaves behind a non-collapsed matrix, thus allowing a better three-dimensional view. Such information extends our knowledge of the expression of interstitial myocardial fibrous tissue in normal hearts and in hypertensive left ventricular hypertrophy and chronic chagasic myocarditis. The progressive accumulation of interstitial collagen fibers in both chronic cardiac diseases may be expected to decrease myocardial compliance and disrupt synchronous contractions of the ventricles during systole, contributing to a spectrum of ventricular dysfunction that involve either the diastolic or systolic phase of the cardiac cycle or both. In hypertensive heart disease myocardial fibrosis can be also implicated in the genesis of ventricular dysrhythmias, possible causes of sudden death among chronic hypertensive patients. Regarding chronic chagasic myocarditis, myocardial fibrosis is probably implicated in the genesis of malignant ventricular tachyarrhythmias (ventricular tachycardia and ventricular fibrillation), major causes of sudden death among patients with chronic Chagas' heart disease. The collagen distribution could interfere on the electrical properties of the myocardium. Fibrosis can block the cardiac impulse that may recycle (re-entry) through an alternative route and could slow conduction. In addition, the thick collagenous septa encompassing muscle fiber bundles could interfere with lateral impulse conduction, which would favor re-entry. Moreover, the methodology used is a useful tool to study the spatial organization of the collagen fibrils of the myocardium under normal and pathological conditions.

Schirrous invasive ductal carcinoma of the breast overexpress p53 oncoprotein.

CONTEXT: Breast cancer is the most important neoplasm in adult women, and its worldwide incidence is growing. The tumoral stroma is very important for modulating the growth and invasion of the tumor itself. The relationship between these two components is not completely understood. Schirrous carcinoma is a variant of ductal invasive carcinoma in which the stroma is very desmoplastic, and the importance of this finding still a motive for debate in the literature. OBJECTIVE: To compare the desmoplastic reactions against biological markers, such as estrogen and progesterone receptors, oncoprotein c-erbB-2 and oncoprotein p53, with the objective of studying the relationship between the tumoral stroma and epithelial cancer cells. TYPE OF STUDY: Retrospective study. SETTING: Cancer Hospital A C Camargo and Faculty of Medicine of Ribeirão Preto, University of São Paulo, São Paulo, Brazil. SAMPLE: 107 adult women operated because of ductal invasive carcinoma. The cases were separated into 4 groups according to the desmoplastic reaction - less than 15 per cent, between 15-50 per cent, 51-85 per cent, and more than 85 per cent fibrosis. The grade of fibrosis was determined by picrus-sirius staining and quantified by using a microscope with a stereo-imaging grid. Immunohistochemical methods were used to determine the expression of the hormonal receptors and c-erbB-2/p53 oncoprotein. MAIN MEASUREMENTS: Extent of desmoplastic reaction versus expression of estrogen and progesterone receptors, oncoprotein c-erbB-2, and oncoprotein p53. RESULTS: The results showed that schirrous carcinoma expresses oncoprotein p53 more frequently than other carcinomas with less extensive desmoplastic reaction. There were no differences between the grade of fibrosis and the other biological markers. CONCLUSION: The intense stromal reaction in invasive ductal carcinoma may modulate the expression of p53. Further investigations should be made with the aim of understanding how this expression determines the proliferative activity in schirrous carcinoma, and whether this overexpression is secondary to mutation of the p53 gene or due to modulation of other molecules of the stroma.

Action of 2-nonenal and 4-hydroxynonenal on phosphoinositide-specific phosopholipase C in undifferentiated and DMSO-differentiated HL-60 cells.

The promyelocytic cell line HL-60 has been used as an in vitro model to study the mechanism of action of two chemotactic aldehydes, 2-nonenal and 4-hydroxynonenal. Increasing aldehyde concentrations have been added to undifferentiated and DMSO-differentiated cells incubated at 37 degrees C and their effect on phosphoinositide-specific phospholipase C has been analysed by using a specific inositol-1,4,5-tris-phosphate assay system. Concentrations of 2-nonenal between 10(-9) and 10(-7) M significantly increased the enzymatic-activity in DMSO-differentiated HL-60 cells, while 10(-9) and 10(-8) M concentrations were active in the undifferentiated cells. 4-Hydroxynonenal was able to activate phospholipase C both in undifferentiated and DMSO-differentiated cells at concentrations ranging from 10(-8) to 10(-6) M. The concentrations of both compounds active on phospholipase C displayed a good correspondence with those which had been reported to be chemotactic towards rat neutrophils. In the case of 4-hydroxynonenal, the present results confirm its ability to activate phospholipase C, which we had previously shown in isolated neutrophil plasma membranes. The comparison of the effects of 2-nonenal and 4-hydroxynonenal on chemotaxis and phospholipase C activation suggests a common mechanism of action for both aldehydes, for which the presence of the double bond seems to be required.