71 resultados para cytochemical


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Diseases. such as cancer and benign prostatic hyperplasia, are related to disruption of the mechanism regulating the balance between cell proliferation and apoptosis in prostatic cells. Since castration and vasectomy might alter that balance, this study evaluates the cell proliferation, apoptosis and height of the secretory epithelium of the ventral-prostate ductal system post-castration and vasectomy. Immunohistochemical (PCNA and Ki67), cytochemical (Fuelgen reaction) and morphometric investigation have been carried out. Cell proliferation indices decreased significantly in both regions of the ventral-prostate ductal system after castration compared to the sham-operated group. The apoptotic index increased significantly after 48 h, declining 7 days post-castration. The cell proliferation indices did not differ after 48 h significantly; however, they increased 7 days post-vasectomy in both regions. The apoptotic index did not differ significantly in either time post-vasectomy. Castration caused an imbalance in favor of apoptosis, whereas vasectomy caused an imbalance in favor of cell proliferation. (c) 2005 International Federation for Cell Biology. Published by Elsevier Ltd. All rights reserved.

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

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

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Cytochemical studies were carried out to establish lipid distribution in the salivary glands of larvae and adult bees, using the imidazole buffer technique. In the duct cells of the larval salivary gland, the reaction was positive in the epicuticle and negative in the glandular lumen. The absence of smooth endoplasmic reticulum and the presence of lipids in the intercellular space suggest that lipids absorbed from the haemolymph could be used in the constitution of the epicuticle, after having been conveyed through the epithelium. In adult workers (new-emerged, nurse and forager workers), the head salivary glands presented a positive reaction in the secretion in glandular lumen, identifying its lipidic nature.

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Histological and histochemical analyses were carried out in order to evaluate the influence of the topical application of a synthetic juvenile hormone on the secretory cycle and degeneration of the venom gland of Apis mellifera. Newly emerged workers received the topical application of synthetic hormone and the results were compared to the normal development of the secretory cycle in virgin and mated queens. The first worker group received the juvenile hormone diluted in hexane (2 mu g/mu L), the second received only mu L of hexane, and the third did not receive any kind of application. After the application the workers were returned to the colony and collected at the ages of 14 and 25 days of adult life. The groups with virgin queens and the other with mated queens, did not receive the treatment. The results show that the individuals treated with juvenile hormone and with pure hexane presented differences in the histological and cytochemical aspects of the secretory cells of the venom gland. The data indicate that both the juvenile hormone and hexane accelerate the activity of the secretory cycle and the degeneration of the venom gland; however, the juvenile hormone proved to be more effective than hexane. (c) 2006 Elsevier Ltd. All rights reserved.

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The morphological and histochemical features of degeneration in honeybee (Apis mellifera) salivary glands were investigated in 5th instar larvae and in the pre-pupal period. The distribution and activity patterns of acid phosphatase enzyme were also analysed. As a routine, the larval salivary glands were fixed and processed for light microscopy and transmission electron microscopy. Tissue sections were subsequently stained with haematoxylin-eosin, bromophenol blue, silver, or a variant of the critical electrolyte concentration (CEC) method. Ultrathin sections were contrasted with uranyl acetate and lead citrate. Glands were processed for the histochemical and cytochemical localization of acid phosphatase, as well as biochemical assay to detect its activity pattern. Acid phosphatase activity was histochemically detected in all the salivary glands analysed. The cytochemical results showed acid phosphatase in vesicles, Golgi apparatus and lysosomes during the secretory phase and, additionally, in autophagic structures and luminal secretion during the degenerative phase. These findings were in agreement with the biochemical assay. At the end of the 5th instar, the glandular cells had a vacuolated cytoplasm and pyknotic nuclei, and epithelial cells were shed into the glandular lumen. The transition phase from the 5th instar to the pre-pupal period was characterized by intense vacuolation of the basal cytoplasm and release of parts of the cytoplasm into the lumen by apical blebbing; these blebs contained cytoplasmic RNA, rough endoplasmic reticule and, occasionally, nuclear material. In the pre-pupal phase, the glandular epithelium showed progressive degeneration so that at the end of this phase only nuclei and remnants of the cytoplasm were observed. The nuclei were pyknotic, with peripheral chromatin and blebs. The gland remained in the haemolymph and was recycled during metamorphosis. The programmed cell death in this gland represented a morphological form intermediate between apoptosis and autophagy.

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The silk glands of bees are a good model for the study of cell death in insects. With the objective to detect the nuclear features during glandular regression stage, larvae at the last instar and pre-pupae were collected and their silk glands were dissected and processed for ultrastructural analysis and histologically for cytochemical and imunocytochemical analysis. The results showed that the cellular nuclei exhibited characteristics of death by atypical apoptosis as well as autophagic cell death. Among the apoptosis characteristic were: nuclear strangulation with bleb formation in some nuclei, DNA fragmentation in most of the nuclei and nucleolar fragmentation. Centripetal chromatin compaction was observed in many nuclei, forming a perichromatin halo differing from typical apoptotic nuclei. With regards to the characteristics of autophagic-programmed cell death, most relevant was the delay in the collapse of many nuclei. (C) 2006 Elsevier Ltd. All rights reserved.

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

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

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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The wasps of the genus Polistes have been considered the key to understanding the evolution of social behavior in Hymenoptera. Several studies have shown that the development of organized insect societies was accompanied by the evolution of structures like exocrine glands, which became specialized to perform specific functions. This article investigates the ultrastructural and cytochemical features of the hypopharyngeal glands of Polistes versicolor. These glands have been studied in depth in social bees, where they occur only in nurses and produce the royal jelly. Our results revealed that these glands basically did not vary among individuals or between sexes. They are constituted by spherical cells, each with a large nucleus and well-developed rough endoplasmic reticulum. Secretion vesicles are abundant, but lipid droplets were not observed, indicating that these glands may not have a role in pheromone synthesis. Acid phosphatase was detected in lysosomes, and also free in the cytosol, but did not seem to be related with cell death. Thus, our results suggest that the hypopharyngeal glands of P. versicolor may not have a specialized social role, but could produce digestive enzymes.

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

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Mg2+-dependent ATPases were investigated in Malpighian tubules of the blood-sucking insect, Triatoma infestans, with cytochemical procedures for light and electron microscopy. The aim was to establish patterns of enzyme occurrence in the blood-sucking insect under control rearing conditions for further comparisons with animals subjected to the action of stress factors. Enzyme activity was found in laminated "concretions" present in distal cells, in edges of urate crystals at the lumen of the proximal region of tubules, in the basement membrane of proximal cells, and variously distributed in plasmalemma invaginations of both distal and proximal cells. Presence of ATPases in the "concretions" and urate crystals is presumed to be due to engulfment of other ATPase-containing components during formation of these structures. Cytochemical reactivity in the basement membrane and plasmalemma invaginations is assumed to be involved with active transport of waste molecules from and to hemolymph and differs as a function of the Malpighian tubule region. This paper provides a basic understanding of the enzyme occurrence in the blood sucking insects, and can be used as a pattern for comparative means of the staining patterns among Triatominae species. (C) 2011 Elsevier Ltd. All rights reserved.