Immunocytochemical localization of heparin in secretory granules of rat peritoneal mast cells using a monoclonal anti-heparin antibody (ST-1)

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.

Tibial segmental bone defect treated with bone plate and cage filled with either xenogeneic composite or autologous cortical bone graft

Tibia segmental defect healing in sheep were clinically, radiographically and histologically evaluated. Twelve young sheep aged four to five months were divided into two groups, G1 and G2. A 3.5 cm long segmental defect was created in the right tibial diaphysis with maintenance of the periosteum. The bone defects in both groups were stabilized with a bone plate combined with a titanium cage. In G1 the cage was filled with pieces of autologous cortical bone graft. In G2 it was filled with a composite biomaterial which consisted of inorganic bovine bone, demineralized bovine bone, a pool of bovine bone morphogenetic proteins bound to absorbable ultra-thin powdered hydroxyapatiteand bone-derived denaturized collagen. Except for one G1 animal, all of them showed normal limb function 60 days after surgery. Radiographic examination showed initial formation of periosteal callus in both groups at osteo-tomy sites, over the plate or cage 15 days postoperatively. At 60 and 90 days callus remodeling occurred. Histological and morphometric analysis at 90 days after surgery showed that the quantity of implanted materials in G1 and G2 were similar, and the quantity of new bone formation was less (p = 0.0048) and more immature in G1 than G2, occupying 51 +/- 3.46% and 62 +/- 6.26% of the cage space, respectively. These results suggest that the composite biomaterial tested was a good alternative to autologous cartical bone graft in this experimental ovine tibial defect. However, additional evaluation is warranted prior to its clinical usage.

Ferritin in iron containing granules from the fat body of the honeybees Apis mellifera and Scaptotrigona postica

It is already known that the behaviour of the honeybee Apis mellifera is influenced by the Earth's magnetic field. Recently it has been proposed that iron-rich granules found inside the fat body cells of this honeybee had small magnetite crystals that were responsible for this behaviour. In the present work, we studied the iron containing granules from queens of two species of honeybees (A. mellifera and Scaptotrigona postica) by electron microscopy methods in order to clarify this point. The granules were found inside rough endoplasmic reticulum cisternae. Energy dispersive X-ray analysis of granules from A. mellifera showed the presence of iron, phosphorus and calcium. The same analysis performed on the granules of S. postica also indicated the presence of these elements along with the additional element magnesium. The granules of A. mellifera were composed of apoferritin-like particles in the periphery while in the core, clusters of organised particles resembling holoferritin were seen. The larger and more mineralised granules of S. postica presented structures resembling ferritin cores in the periphery, and smaller electron dense particles inside the bulk. Electron spectroscopic images of the granules from A. mellifera showed that iron, oxygen and phosphorus were co-localised in the ferritin-like deposits. These results indicate that the iron-rich granules of these honeybees are formed by accumulation of ferritin and its degraded forms together with elements present inside the rough endoplasmic reticulum, such as phosphorus, calcium and magnesium. It is suggested that the high level of phosphate in the milieu would prevent the crystallisation of iron oxides in these structures, making very unlikely their participation in magnetoreception mechanisms. They are most probably involved in iron homeostasis. (C) 2001 Elsevier B.V. Ltd. All rights reserved.

COMPARATIVE STUDIES ON PIGMENT GRANULES AND PIGMENT DISTRIBUTION IN THE COMPOUND EYES OF WILD-TYPE AND MUTANT WORKER HONEYBEES .2. AN ULTRASTRUCTURAL ANALYSIS

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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.

Auditory processing disorder in patients with language-learning impairment and correlation with malformation of cortical development

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Thermal behaviour of corn starch granules under action of fungal alpha-amylase

Corn starch, partially hydrolyzed by fungal alpha-amylase was investigated by using thermal analysis, microscopy and X-ray diffraction. After enzymatic treatment lower degradation onset temperatures were observed. DSC analysis showed almost similar range of gelatinization temperature, however, the enthalpies of gelatinization increased for the partially hydrolyzed starch granules. According to the X-ray diffraction analysis, stronger cereal pattern peaks were recognized after enzymatic digestion. The results suggested that the hydrolysis was more pronounced in the amorphous part of the starch granules.

Cytochemical characterization of the endomembranous system during oocyte secondary growth in Serrasalmus spilopleura (Teleostei, Characiformes, Characidae)

The endomembranous system of Serrasalmus spilopleura oocyte secondary growth was analysed using structural and ultrastructural cytochemical techniques. In vitellogenic oocytes, the endoplasmic reticulum components, the nuclear envelope intermembranous space, some Golgi dictiossomes, lysosomes, yolk granules, regions of the egg envelope and sites of the follicle cells react to acid phosphatase detection (AcPase). The cortical alveoli, some heterogeneous cytoplasmic structures, regions of the egg envelope, and sites of the follicle cells are strongly contrasted by osmium tetroxide and zinc iodide impregnation (ZIO). The endoplasmic reticulum components, some vesicles, and sites of the follicle cells also react to osmium tetroxide and potassium iodide impregnation (KI). The biosynthetic pathway of lysosomal proteins, such as acid phosphatase, required for vitellogenesis, involves the endoplasmic reticulum, Golgi complex, vesicles with inactive hydrolytic enzymes, and, finally, lysosomes. In S. spilopleura oocytes at secondary growth, the endomembranous system takes part in the production of the enzymes needed for vitellogenesis, and in the metabolism of yolk exogenous components (AcPase detection). The endomembranous system compartments also show reduction capacity (KI reaction) and are involved in the metabolism of proteins rich in SH-groups (ZIO reaction).

Mandibular cortical bone evaluation on cone beam computed tomography images of patients with bisphosphonate-related osteonecrosis of the jaw

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

The ultrastructural aspects of vitellogenesis or oocyte secondary growth in Serrasalmus spilopleura (Teleostei, Characiformes, Serrasalminae)

Oocyte secondary growth in S. spiloleura corresponds to the period in which different vesicular structures are formed, including the cortical alveoli and the yolk granules. The oocytes with cortical alveolus formation show vesicular structures with filamentous content in the cortical cytoplasmic region, which are the cortical alveolus precursors. In these oocytes, electron-dense vesicles of heterogenous content are dispersed in the inner cytoplasmic region and their nuclei are irregular, showing many nucleoli of different sizes. The oocytes in vitellogenesis are filled with many vesicles. The cortical alveolus precursors are in the peripheral region, and electron-dense granules are seen near to the nucleus. These fuse and form yolk granules. The oocytes in vitellogenesis show a very irregular nucleus that has nucleoli of different sizes. In the oocytes in final vitellogenesis, the yolk granules are scattered throughout the cytoplasm, displacing the cortical alveoli toward cell periphery. The nucleus is similar to the other stages.