Mesenchymal stem cells engrafted in a fibrin scaffold stimulate Schwann cell reactivity and axonal regeneration following sciatic nerve tubulization

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Mitochondria in the midgut epithelial cells of sugarcane borer parasitized by Cotesia flavipes (Cameron, 1891)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Comparative structural analysis of neuromuscular junctions in mice at different ages

The authors studied the histochemical and ultrastructural modifications that occur in the neuromuscular junctions (NMJ) of fibularis longus muscles of mice with an age range of 3 to 21 months. Twenty-four male and female animals were killed at 3, 5, 14 and 21 months of age: 7 of them at 3 months, 4 of them at 5 month, 9 at 14 months and 4 at 21 months. The fibularis longus muscles were processed and their NMJ examined with the transmission electron microscope. The most relevant changes were associated with the degeneration and retraction of terminal axons, i.e., axons poor in synaptic vesicles with degenerated mitochondria, and exhibiting multivesicular bodies and vacuoles; exposed and widened junctional folds and cytoplasmic processes of Schwann cells located in the synaptic gutter. The presence of lysosomes or lipofuchsin in the juxtajunctional sarcoplasm was also noted. These observations suggest that the phenomena of retraction and budding occur in the NMJ with advancing age, with a predominance of events associated with degeneration, leading to profound changes in NMJ shape.

Granular cell tumour (Abrikossoff's tumour): Case series

This case series describes three unreported cases of an uncommon benign neoplasm named Abrikossoff's tumour or granular cell tumour (GCT). This mesenchymal neoplasm apparently arises from neural or Schwann cell origin with benign and malignant forms. All cases presented here were unique nodules on oral mucosa, coming out from the connective tissue, and occurring in women with age ranging from 30 to 42 years. The histological aspects of the GCT showed large granular cells arranged in groups and nests of connective tissue separating pseudoepitheliomatous overlying surface. This feature can possibly be misunderstood with squamous cell carcinoma. The differentiation between malignant and benign GCT is evaluated by the presence of metastases which is considered the only reliable criterion for malignancy. © 2005 Elsevier Ltd. All rights reserved.

Cyclosporine improves remyelination in diabetic rats submitted to a gliotoxic demyelinating model in the brainstem

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S-100 protein: is it useful as a tumour marker in diagnostic immunocytochemistry

A heterogeneous group of 159 tumours was studied for the presence of S-100 protein by the immunoperoxidase technique in order to determine whether this marker may be of value in facilitating immunocytochemical diagnosis. Among cases of melanocytic and pigmented lesions, S-100 was widely distributed and demonstrated the strongest degrees of reactivity. S-100 protein was identified in virtually all nerve sheath tumours such as schwannomas, neurofibromas, myxoid sheath nerve tumour and also in some tumours of controversial histogenesis such as granular cell tumours. The great majority of carcinomas did not express S-100, with only two cases of breast carcinoma displaying focal S-100 staining. In a miscellaneous group of tumours S-100 was demonstrated in chordomas, myoepitheliomas and Wilms' tumour with Schwann cell differentiation. Despite its presence in a wide array of cell types, S-100 protein continues to be an extremely useful marker especially for soft tissue and peripheral nervous system tumours.

Structural and ultrastructural characteristics of interrenal gland and chromaffin cell of matrinxa, Brycon cephalus Gunther 1869 (Teleostei-Characidae)

This work presents the structure and ultrastructure of the interrenal gland and chromaffin cells, as well as the morphology of the head kidney of Brycon cephalus, the head kidney is composed of fused bilateral lobes located anterior to the swim bladder and ventrolateral to the spinal column, the parenchyma revealed lympho-haematopoietic tissue, melano-macrophage centres, interrenal gland and chromaffin cells. The interrenal gland consisted of cords or strands of cells grouped around the posterior cardinal vein and their branches. Chromaffin cells are found in small groups, closely associated with the interrenal gland and/or under the endothelium of the posterior cardinal vein. So far, the ultrastructural analysis has revealed only one interrenal cell type which contained abundant smooth endoplasmic reticulum and numerous mitochondria with tubulo-vesicular cristae, characteristic of steroid-producing cells. Two types of chromaffin cells were observed. The first type was characterized by the presence of vesicles with round, strongly electron-dense granules, which were eccentrically located, Such cells were interpreted as noradrenaline cells, Meanwhile, cells which contained smaller vesicles and electron-lucent granules, with a small halo separating the granule from the vesicular limiting membrane, were identified as adrenaline cells.

Cell Death in Salivary Glands of Rhipicephalus (Boophilus) microplus (Canestrini, 1887) (Acari: Ixodidae) Females at Semi-engorged Feeding Stage

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Cellular and molecular characterization of an embryonic cell line (BME26) from the tick Rhipicephalus (Boophilus) microplus

The cellular and molecular characteristics of a cell line (BME26) derived from embryos of the cattle tick Rhipicephalus (Boophilus) microplus were studied. The cells contained glycogen inclusions, numerous mitochondria, and vesicles with heterogeneous electron densities dispersed throughout the cytoplasm. Vesicles contained lipids and sequestered palladium meso-porphyrin (Pd-mP) and rhodamine-hemoglobin, suggesting their involvement in the autophagic and endocytic pathways. The cells phagocytosed yeast and expressed genes encoding the antimicrobial peptides (microplusin and defensin). A cDNA library was made and 898 unique mRNA sequences were obtained. Among them, 556 sequences were not significantly similar to any sequence found in public databases. Annotation using Gene Ontology revealed transcripts related to several different functional classes. We identified transcripts involved in immune response such as ferritin, serine proteases, protease inhibitors,. antimicrobial peptides, heat shock protein, glutathione S-transferase, peroxidase, and NADPH oxidase. BME26 cells transfected with a plasmid carrying a red fluorescent protein reporter gene (DsRed2) transiently expressed DsRed2 for up to 5 weeks. We conclude that BME26 can be used to experimentally analyze diverse biological processes that occur in R. (B.) microplus such as the innate immune response to tick-borne pathogens. (C) 2008 Elsevier Ltd. All rights reserved.

Effects of isocoumarins isolated from Paepalanthus bromelioides on mitochondria: Uncoupling, and induction/inhibition of mitochondrial permeability transition

Isolated mitochondria may undergo uncoupling, and in presence of Ca2+ at different conditions, a mitochondrial permeability transition (MPT) linked to protein,thiol oxidation, and demonstrated by CsA-sensitive mitochondrial swelling; these processes may cause cell death either by necrosis or by apoptosis. Isocoumarins isolated from the Brazilian plant Paepalanthus bromelioides (Eriocaulaceae) paepalantine (9,10-dihydroxy-5,7-dimethoxy-1H-naptho(2,3c)pyran-1-one), 8,8'-paepalantine dimer, and vioxanthin were assayed at 1-50 mu M on isolated rat liver mitochondria, for respiration, MPT, protein thiol oxidation, and interaction with the mitochondrial membrane using 1,6-diphenyl-1,3,5-hexatriene (DPH). The isocoumarins did not significantly affect state 3 respiration of succinate-energized mitochondria; they did however, stimulate 4 respiration, indicating mitochondrial uncoupling. Induction of MPT and protein thiol oxidation were assessed in succinate-energized mitochondria exposed to 10 mu M Ca2+; inhibition of these processes was assessed in non-energized organelles in the presence of 300 mu M t-butyl hydroperoxide plus 500 mu M Ca2+. Only paepalantine was an effective MPT/protein thiol oxidation inducer, also releasing cytochrome c from mitochondria; the protein thiol oxidation, unlike mitochondrial swelling, was neither inhibited by CsA nor dependent on the presence of Ca2+. Vioxanthin was an effective inhibitor of MPT/protein thiol oxidation. All isocoumarins inserted deeply into the mitochondrial membrane, but only paepalantine dimer and vioxantin decreased the membrane's fluidity. A direct reaction with mitochondrial membrane protein thiols, involving an oxidation of these groups, is proposed to account for MPT induction by paepalantine, while a restriction of oxidation of these same thiol groups imposed by the decrease of membrane fluidity, is proposed to account for MPT inhibition by vioxanthin. (c) 2006 Published by Elsevier B.V..

Ultrastructural features of the glandular region of the stomach of Piaractus mesopotamicus (Holmberg, 1887) with emphasis on the oxyntopeptic cell

The characteristics of the lining and glandular epithelial types of the wall of the stomach of pacu (Piaractus mesopotamicus Holmberg, 1887) were studied by transmission electron microscopy. Columnar mucous cells were observed in the lining epithelial surface and the glandular epithelium that invaginated in the lamina propria showed secretory cells or oxyntopeptic cells as called by some authors in the literature. The columnar epithelial cells are narrow and show a basal nucleus. They are rich in organelles and contain secretory granules of round or rectangular shape heterogeneously electron dense in the apical portion. In the basal region of the glands there are secretory cells. The luminal half of these cells has abundant tubules (tubulo-vesicular system) that communicate with the external medium. Deeper basally in the cytoplasm there are the nucleus, mitochondria of various shapes and other scattered organelles.

Spermatic cell characteristics in Gymnotiformes (Teleostei: Ostariophysi) and their phylogenetic meaning

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ULTRASTRUCTURAL SIMILARITY BETWEEN BAT AND HUMAN MAST-CELL SECRETORY GRANULES

Mast cells in the tongue of the bat (Artibeus lituratus) show a well-developed Golgi area and abundant mitochondria in the granule-free perinuclear cytoplasm. Rough endoplasmic reticulum profiles, free ribosomes, mitochondria, bundles of filaments and a great number of secretory granules are found throughout the remaining cytoplasm. The granules, of various shapes and sizes, are simple containing an electron-dense, homogeneous matrix, coarse particles or cylindrical scrolls, or combinations (cylindrical scrolls with either electron-dense, homogeneous matrix or coarse particle contents). Up to now, scroll-containing granules have been considered to be a unique feature of human mast cells.

Peripheral giant cell granuloma. An immunohistochemical and ultrastructural study.

OBJECTIVE: To study the nature of multinucleated and mononuclear cells from peripheral giant cell granuloma (PGCG). MATERIALS AND METHODS: Formalin-fixed, paraffin-embedded sections of 40 cases of PGCG were immunohistochemically stained for vimentin, alpha I-antichymotrypsin, CD68, S-100 protein, lysozyme, leucocyte common antigen (LCA), factor VIII-related antigen and muscle cell actin. Six cases of PGCG were also studied by transmission electron microscopy. RESULTS: Vimentin, alpha I-antichymotrypsin and CD68 were expressed in both the mononuclear and multinucleated giant cells. Dendritic mononuclear cells, positive for S-100 protein, were noted in 67.5% of the lesions, whereas lysozyme and leucocyte common antigen were detected in occasional mononuclear cells. Ultrastructural examination showed mononuclear cells with signs of phagocytosis and sometimes interdigitations with similar cells. Others presented non-specific characteristics and the third type exhibited cytoplasmic processes and occasional Birbeck granules. Some multinucleated giant cells showed oval nuclei, abundant mitochondria and granular endoplasmic reticulum whereas others presented with irregular nuclei and a great number of cytoplasmic vacuoles. CONCLUSIONS: Immunohistochemical and ultrastructural results suggest that PGCGs of the jaws are composed mainly of cells of the mononuclear phagocyte system and that Langerhans cells are present in two thirds of the lesions.