Navegando por Palavras-chave "electron microscopy"

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    Acute food restriction increases collagen breakdown and phagocytosis by mature decidual cells of mice
    (Churchill Livingstone, 2001-06-01) Spadacci-Morena, D. D.; Katz, S. G.; Universidade Federal de São Paulo (UNIFESP); Inst Butantan
    An ultrastructural study was undertaken on antimesometrial mature decidual tissue of fed and food-restricted mice, on day 9 of pregnancy. the mean ad libitum food intake was established on mice from the 8th till the 9th day of pregnancy. Fed mice were used as controls. Experimental animals were divided into two groups: one was allowed to feed 25% of normal diet and the other 50%. Extracellular collagen fibrils were scarce in fed animals and conspicuous in food restriction. Granular electron-dense deposits and filamentous aggregates of disintegrating collagen fibrils were observed in all food-deprived mice but were rarely noted in fed animals. Intracellular vacuolar structures exhibited other typical cross-banded collagen immersed in finely granular electron-translucent material (clear vacuole) or electron-dense material containing collagen fibrils with a faint periodicity (dark vacuole), the clear and dark vacuoles were scarce in fed animals and evident in food-restricted mice, mainly in those 25% food restricted. Although collagen breakdown may be part of the normal process of decidual tissue remodelling our results suggest that it is enhanced in food-restricted animals. Thus it seems that collagen breakdown is a normal mechanism that may be regulated by the food intake of the pregnant animal. (C) 2001 Harcourt Publishers Ltd.
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    Demonstration of extracellular acid phosphatase activity in the involuting, antimesometrial decidua in fed and acutely fasted mice by combined cytochemistry and electron microscopy
    (Wiley-Blackwell, 1998-09-01) Katz, Sima Godosevicius [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    An ultrastructural cytochemical study of acid phosphatase activity in the antimesometrial decidua on days 9-11 of pregnancy was performed in fed and acutely fasted mice.Specimens were fixed in a buffered mixture of paraformaldehyde and glutaraldehyde and were incubated in a buffered medium containing sodium beta-glycerophosphate and cerium chloride for ultrastructural localization of acid phosphatase activity,Fed and fasted animals showed extracellular acid phosphatase reaction product in the decidual-trophoblast interface, in the region of loosely and tightly packed, mature decidual cells, and in the region of predecidual cells. Reaction product was absent in the region of nondecidualized stromal cells. Extracellular acid phosphatase activity was more conspicuous in the region of mature decidual cells in fasted mice than in fed mice, and it was apparently similar in the region of predecidual cells in both fed and fasted mice. Acid phosphatase reaction product was also observed in lysosomes in all cells studied.Because acid phosphatase activity reflects the presence of lysosomal hydrolases in general, our results suggest that there is matrix degradation by lysosomal enzymes in both fed and fasted mice. These events may be part of the process of tissue remodeling in regions of predecidual cells and mature decidual cells. However, it is also possible that, in the region of mature decidual cells, breakdown of matrix constituents is a mechanism to provide nutrients for the growing fetus. This mechanism is probably enhanced in fasted mice. (C) 1998 Wiley-Liss, Inc.
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    Disruption of myofibrillar proteins in cardiac muscle of Calomys callosus chronically infected with Trypanosoma cruzi and treated with immunosuppressive agent
    (Springer, 2005-10-01) Taniwaki, N. N.; Andreoli, W. K.; Calabrese, K. S.; Silva, S. da; Mortara, R. A.; Universidade Federal de São Paulo (UNIFESP); Inst Adolfo Lutz Registro; Dept Protozool
    Calomys callosus (Rodentia: Cricetidae) chronically infected with CL strain of Trypanosoma cruzi undergo recrudescence of the acute phase when treated with the immunosuppressor cyclophosphamide. the distribution of cytoskeletal proteins in cardiac tissue of immunosuppressed animals was mapped by immunofluorescence and electron microscopy to evaluate myofibrillar distribution during the intracellular life cycle of T. cruzi. Cardiac muscle sections showed enhancement of myocarditis and parasite proliferation after immunosuppression. Immunofluorescence using monoclonal antibodies against myosin, actin, desmin, titin, tropomyosin, and troponin T demonstrated disruption and loss of contractile proteins, such as myosin and actin. Desmin and titin were irregularly distributed in close proximity to parasite nests. Ultrastructural observations confirmed alterations of cardiac cells with Z-line fragmentation, indistinguishable I-bands and A-bands, and loss of myofibrillar elements. the disruption of the muscle cell architecture was greater as infection progressed, probably as a result of increased myocarditis and physical displacement due to the activity of flagellated parasites.
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    Evidence of Noncompetent HIV after Ex Vivo Purging Among ART-Suppressed Individuals
    (Mary Ann Liebert, Inc, 2017) Samer, Sadia [UNIFESP]; Namiyama, Gislene; Oshiro, Telma; Arif, Muhammad Shoaib [UNIFESP; da Silva, Wanessa Cardoso; Araripe Sucupira, Maria Cecilia [UNIFESP; Janini, Luiz Mario [UNIFESP; Diaz, Ricardo Sobhie [UNIFESP
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    Extracellular and intracellular degradation of collagen by trophoblast giant cells in acute fasted mice examined by electron microscopy
    (Churchill Livingstone, 1995-12-01) Katz, S. G.; Universidade Federal de São Paulo (UNIFESP)
    The fine structure of trophoblast giant cells and their interaction with collagen at the antimesometrial region on the 9th day of pregnancy was examined in fed and acute fasted mice, Collagen fibrils and filamentous aggregates (disintegrating collagen fibrils) were observed in the extracellular space, Three types of intracellular vacuoles containing collagen fibrils were present: vacuole type A exhibited typical cross-banded collagen immersed in finely granular electron-translucent material; and vacuoles type B and C showed electron-opaque granular material containing, respectively, faint cross-banded collagen and narrow clear stripes often with faint periodicity, in fed animals vacuoles type B were absent and the others were less evident.Only fasted animals showed extracellular acid phosphatase activity on collagen fibrils, filamentous aggregates and confined regions of the extracellular space. Intracellular acid phosphatase activity was observed in vacuoles type B and in lysosomes.The results indicate that trophoblast giant cells are capable of breaking down extracellular collagen and also of internalizing collagen for intracellular degradation, It is likely that these events are part of the process of invasion of the uterine wall, However, in fasted mice, collagen breakdown is more pronounced, and it may therefore contribute to the provision of amino acids and other nutrients for the undernourished fetus.
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    Extracellular breakdown of collagen by mice decidual cells. A cytochemical and ultrastructural study
    (Inst Histol Embriol-conicet, 2005-12-01) Katz, Sima Godosevicius [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    The interaction of antimesometrial decidual cells and collagen fibrils was studied by light microscopy and ultrastructural cytochemistry in fed and acutely fasted mice on days 9-11 of pregnancy.Fibrillar elements in the extracellular space consisted of collagen fibrils and filamentous aggregates (disintegrating collagen fibrils). Intracellular vacuoles exhibited typical collagen immersed in electron-translucent material (clear vacuoles) and faint cross-banded collagen immersed in electron-opaque material (dark vacuoles).Fibrillar elements showed extracellular acid phosphatase activity which was stronger in the region of mature decidua than in predecidual cells region in all animals; it was conspicuous in mature decidua of fasted animals. Intracellular acid phosphatase activity was observed in dark vacuoles and lysosomes, and was absent in clear vacuoles in all cells studied.Since acid phosphatase activity reflects the presence of lysosomal hydrolases in general, the results indicate that breakdown of extracellular collagen occurs by release of lysosomal enzymes by decidual cells and also by internalization of collagen for intracellular degradation in fed and fasted mice. Collagen breakdown may be part of the process of tissue remodeling in mature and predecidual regions, however, in mature decidua, collagen breakdown is enhanced and may therefore contribute to nutrition of the fetus, specially in acutely fasted mice.
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    Fibrinolytic activity is associated with presence of cystic medial degeneration in aneurysms of the ascending aorta
    (Wiley-Blackwell, 2010-12-01) Borges, Luciano F. [UNIFESP]; Gomez, Delphine; Quintana, Mercedes; Touat, Ziad; Jondeau, Guillaume; Leclercq, Anne; Meilhac, Olivier; Jandrot-Perrus, Martine; Gutierrez, Paulo S.; Freymuller, Edna [UNIFESP]; Vranckx, Roger; Michel, Jean-Baptiste; Univ Paris 07; Universidade Federal de São Paulo (UNIFESP); Ctr Reference Syndrome Marfan & Syndromes Apparen; Universidade de São Paulo (USP)
    Fibrinolytic activity is associated with presence of cystic medial degeneration in aneurysms of the ascending aortaAims:Thoracic ascending aortic aneurysms (TAA) are characterized by elastic fibre breakdown and cystic medial degeneration within the aortic media, associated with progressive smooth muscle cell (SMC) rarefaction. the transforming growth factor (TGF)-beta/Smad2 signalling pathway is involved in this process. Because the pericellular fibrinolytic system activation is able to degrade adhesive proteins, activate matrix metalloproteinase (MMP), induce SMC disappearance and increase the bioavailability of TGF-beta, the aim was to investigate the plasminergic system in TAA.Methods and results:Ascending aortas [21 controls and 19 TAAs (of three different aetiologies)] were analysed. Immunohistochemistry showed accumulation of t-PA, u-PA and plasmin in TAAs, associated with residual SMCs. Overexpression of t-PA and u-PA was confirmed by reverse transcription-polymerase chain reaction (RT-PCR), immunoblotting and zymography on TAA extracts and culture medium conditioned by TAA. Plasminogen was present on the SMC surface and inside cytoplasmic vesicles, but plasminogen mRNA was undetectable in the TAA medial layer. Plasmin-antiplasmin complexes were detected in TAA-conditioned medium and activation of the fibrinolytic system was associated with increased fibronectin turnover. Fibronectin-related material was detected immunohistochamically in dense clumps around SMCs and colocalized with latent TGF-beta binding protein-1.Conclusions:The fibrinolytic pathway could play a critical role in TAA progression, via direct or indirect impact on ECM and consecutive modulation of TGF-beta bioavailability.
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    Immunocytochemical localization of heparin in secretory granules of rat peritoneal mast cells using a monoclonal anti-heparin antibody (ST-1)
    (Histochemical Soc Inc, 1997-02-01) Oliani, Sonia M.; Freymuller, Edna [UNIFESP]; Takahashi, Helio K. [UNIFESP]; Straus, Anita H. [UNIFESP]; Universidade Federal de São Paulo (UNIFESP); UNESP
    We performed immunogold labeling with an ST-1 monoclonal antibody (IgM), specific for intact heparin, to define the subcellular localization of heparin in mast cells. Rat peritoneal mast cells were fixed by a modified Karnovsky method and embedded in Araldite. Ultrathin sections were first treated with sodium periodate and then sequentially incubated with MAb ST-1, rabbit anti-mouse IgM, and protein A-gold. By transmission electron microscopy, gold particles were localized inside cytoplasmic granules of peritoneal mast cells. In contrast, with the same procedure, no labeling was observed in mast cells from rat intestinal mucosa. Control sections of rat peritoneal or intestinal mucosa mast Mast cells cells treated with an irrelevant MAb (IgM) did not show any labeling. Treatment with nitrous Heparin acid abolished the reactivity of MAb ST-1 with peritoneal mast cells. These results Granules show that different mast cells can be identified regarding their heparin content by immunochemical procedures using MAb ST-1.
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    Sertoli cell morphological alterations in albino rats treated with etoposide during prepubertal phase
    (Cambridge Univ Press, 2008-06-01) Stumpp, Taiza [UNIFESP]; Freymuller, Edna [UNIFESP]; Miraglia, Sandra M. [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    Sertoli cells are very important to spermatogenesis homeostasis because they control germ cell proliferation, differentiation, and death. Damages to Sertoli cells cause germ cell death and affect fertility. Etoposide is a potent chemotherapeutic drug largely used against a variety of cancers. However, this drug also kills normal cells, especially those undergoing rapid proliferation. in the testis, etoposide acts predominantly on intermediate and type B spermatogonia. Etoposide was shown to permanently alter Sertoli cell function when administered to prepubertal rats. Based on this, we decided to investigate whether etoposide can affect Sertoli cell morphology. for this, 25-day-old rats were treated with etoposide during 8 consecutive days and killed at 32, 45, 64, 127, and 180 days old. Testes were fixed in Bonin's liquid or in a mixture of 2.5% glutaraldehyde and 2% formaldehyde for analysis under light and electron microscopes, respectively. Sertoli cells showed morphological alterations such as the presence of chromatin clumps close to the nuclear membrane, nucleus displacement, and cytoplasmic vacuolization. Some Sertoli cells also showed nuclear and cytoplasmic degenerative characteristics, suggesting that etoposide causes severe damages to Sertoli cell.
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    Subretinal injection of preservative-free triamcinolone acetonide and supernatant vehicle in rabbits: an electron microscopy study
    (Springer, 2008-03-01) Maia, Mauricio [UNIFESP]; Penha, Fernando Marcondes [UNIFESP]; Farah, Michel Eid [UNIFESP]; Dib, Eduardo [UNIFESP]; Principe, Andre [UNIFESP]; Lima Filho, Acacio A. S. [UNIFESP]; Magalhaes, Octaviano [UNIFESP]; Freymueller, Edna [UNIFESP]; Rodrigues, Eduardo B. [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    Background To evaluate the effect of injections of benzyl alcohol (BA)-free triamcinolone acetonide (TA) solution (MTA-PF) and the supernatant vehicle of TA (STA) containing BA into the subretinal space of rabbit eyes.Methods Sixteen rabbits underwent vitrectomy and subretinal injection of 0.02 ml of either 40 mg/ml MTA-PF, 40 mg/ml STA, or balanced salt solution (BSS). the animals were examined 6, 12, and 24 hours and 14 days after the procedure by fundus examination and fluorescein angiography (FA), as well as histological studies by light and transmission electron microscopy. the histological injury was classified in four stages: (1) stage 1, photoreceptor outer segment injury, (2) stage 2, stage 1 + photoreceptor inner segment injury, (3) stage 3, stage 2 + outer nuclear layer damage, and (4) stage 4, stage 3 + retinal pigment epithelium (RPE) damage.Results FA showed no window defects in areas where MTA-PF, STA, or BSS have been injected. Histological examination revealed that subretinal BSS-injection resulted in stage 1 damage during entire follow-up. Subretinal injection of MTA-PF resulted in damage stage 2 at 24 h and 14 days after surgery. However, at the STA position, stage 3 damage was noted 24 h and 14 days postoperatively. No RPE or choroidal damage was observed.Conclusions the histological lesions induced by subretinal STA were more relevant than the damage induced by MTA-PF. the vehicle BA may be involved in these abnormalities. the data indicate that care must be taken when using TA during internal limiting membrane peeling in macular hole surgery, due to the possibility of unintentional subretinal migration and for retinal pharmacotherapy.
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    Three-Dimensional Reconstruction of Trypanosoma cruzi Epimastigotes and Organelle Distribution Along the Cell Division Cycle
    (Wiley-Blackwell, 2011-07-01) Ramos, Thiago Cesar Prata [UNIFESP]; Freymüller-Haapalainen, Edna [UNIFESP]; Schenkman, Sergio [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    Trypanosoma cruzi is the protozoan that causes Chagas disease. It divides in the insect vector gut or in the cytosol of an infected mammalian cell. T cruzi has one mitochondrion, one Golgi complex, one flagellum, and one cytostome. Here, we provide three-dimensional (3D) models of this protozoan based on images obtained from serial sections on electron microscopy at different stages of the cell cycle. Ultrathin serial sections were obtained from Epon (TM) embedded parasites, photographed in a transmission electron microscope, and 3D models were generated using Reconstruct and Blender 3D modeling softwares. the localization and distribution of organelles was evaluated and attributed to specific morphological patterns and deduced by distribution of specific markers by immunofluorescence analysis. the new features found in the 3D reconstructions are (1) the electron-dense chromatin is interconnected leaving an internal space for a centrally located nucleolus; (2) the kinetoplast is accommodated within a separated branch of the tubular and single mitochondrion; (3) the disk shaped kinetoplast, which is the mitochondrial DNA, duplicates from the interior in G2 phase; (4) the mitochondrion faces the external membrane and shrinks to accommodate an enlarged number of cytosolic vesicles from G1 to G2; (5) the cytostome progress from the parasite surface toward the posterior end contouring the kinetoplast and nucleus and retracts during cell cycle. These new observations might help understanding how organelles are formed and distributed in early divergent eukaryotic cells and provides a useful method to understand the organelle distribution in small eukaryotic cells. (C) 2011 International Society for Advancement of Cytometry
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    TOXICITY and RETINAL PENETRATION of INFLIXIMAB in PRIMATES
    (Lippincott Williams & Wilkins, 2012-03-01) Melo, Gustavo B. [UNIFESP]; Moraes Filho, Milton N. [UNIFESP]; Rodrigues, Eduardo B. [UNIFESP]; Regatieri, Caio V. [UNIFESP]; Dreyfuss, Juliana L. [UNIFESP]; Penha, Fernando M. [UNIFESP]; Pinheiro, Marcelo M. [UNIFESP]; Coimbra, Rita C. S. G. [UNIFESP]; Haapalainen, Edna Freymuller [UNIFESP]; Farah, Michel E. [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    Purpose: To evaluate the retinal penetration and toxicity of two doses of intravitreal infliximab in primates.Methods: Ten marmosets (Callithrix jacchus) were given intravitreal injection of 100 mu g or 400 mu g of infliximab, and balanced salt solution served as control. At baseline and after 24 hours (5 animals) and 7 days (the other 5), the eyes were examined by electroretinography. They were then killed (at 24 hours and 7 days) and assessed by light microscopy and transmission electron microscopy for toxicity and immunohistochemistry, using a biotinylated anti-human immunoglobulin G, to evaluate retinal penetration.Results: There was no difference over 50% of the electroretinography b-wave between baseline and the time points studied in all animals. Light and electron microscopy, and electroretinography analysis, showed no signs of toxicity in any of the animals. Strong presence of infliximab was observed in all retinal layers 7 days after intravitreal injection at both doses (100 and 400 mu g).Conclusion: Infliximab at doses of 100 and 400 mu g seemed to cause no damage to the retina 24 hours and 7 days after its intravitreal injection, and deeply penetrated all its layers, in primates. These results encourage future perspectives for the treatment of chronic inflammatory diseases of the retina in humans. RETINA 32: 606-612, 2012