Doxazosin reduces cell proliferation and increases collagen fibers in rat prostatic lobes

We investigated the effects of doxazosin (Dox), an alpha-adrenoceptor antagonist used clinically for the treatment of benign prostatic hyperplasia (BPH), on the rat prostatic complex by assessing structural parameters, collagen fiber content, cell proliferation, and apoptosis. Adult Wistar rats were treated with Dox (25 mg/kg per day), and the ventral (VP), dorsolateral, and anterior prostate (AP) regions of the prostate complex were excised at 3, 7, and 30 days after treatment. At 24 h before being killed, the rats were injected once with 5-bromodeoxyuridine (BrdU; thymidine analog) to label mitotically active cells. The prostates were weighed and processed for histochemistry, morphometry-stereology, immunohistochemistry for BrdU, Western blotting for proliferating cell nuclear antigen (PCNA), and the TUNEL reaction for apoptosis. Dox-treated prostate lobes at day 3 presented increased weight, an enlarged ductal lumen, low cubical epithelial cells, reduced epithelial folds, and stretched smooth muscle cells. However, at day 30, the prostates exhibited a weight reduction of ∼20% and an increased area of collagen and reticular fibers in the stromal space. Dox also reduced epithelial cell proliferation and increased apoptosis in the three prostatic lobes. Western blotting for PCNA confirmed the reduction of cell proliferation by Dox, with the AP and VP being more affected than the dorsal prostate. Thus, Dox treatment alters epithelial cell behavior and prostatic tissue mechanical demand, inducing tissue remodeling in which collagen fibers assume a major role. © 2007 Springer-Verlag.

rastreamento histoquímico, fitoquímico e biológico de folhas de Plinia cauliflora (DC.) Kausel (Myrtaceae)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Expression of acid phosphatase in the seminiferous epithelium of vertebrates

Acid phosphatases (AcPs) are known to provide phosphate to tissues that have high energy requirements, especially during development, growth and maturation. During spermatogenesis AcP activity is manifested in heterophagous lysosomes of Sertoli cells. This phagocytic function appears to be hormone-independent. We examined the expression pattern of AcP during the reproductive period of four species belonging to different vertebrate groups: Tilapia rendalli (Teleostei, Cichlidae), Dendropsophus minutus (Amphibia, Anura), Meriones unguiculatus (Mammalia, Rodentia), and Oryctolagus cuniculus (Mammalia, Lagomorpha). To demonstrate AcP activity, cryosections were processed for enzyme histochemistry by a modification of the method of Gömöri. AcP activity was similar in the testes of these four species. Testes of T. rendalli, D. minutus and M. unguiculatus showed an intense reaction in the Sertoli cell region. AcP activity was detected in the testes of D. minutus and O. cuniculus in seminiferous epithelium regions, where cells are found in more advanced stages of development. The seminiferous epithelium of all four species exhibited AcP activity, mainly in the cytoplasm of either Sertoli cells or germ cells. These findings reinforce the importance of AcP activity during the spermatogenesis process in vertebrates. © FUNPEC-RP.

Cellular localization of androgen synthesis in equine granulosa-theca cell tumors: Immunohistochemical expression of 17α-hydroxylase/17,20-lyase cytochrome P450

Elevated blood testosterone concentrations, often accompanied by male-typical behaviors, is a common signalment of mares with granulosa-theca cell tumors (GCTCs), but no definitive information exists regarding the cellular differentiation of tumors associated with androgen secretion. This study was conducted to localize and thereby define the cellular expression of 17α-hydroxylase/17,20-lyase cytochrome P450 (P450c17), the enzyme most directly responsible for androgen synthesis, in 30 GTCTs and control tissues (gonads and adrenal glands) using immuno-histochemistry (IHC). Immuno-reactivity for P450c17 was evident in approximately half of 30 specimens examined, was most consistent in the interstitial cells surrounding existing or developing cysts, and was less intense in cells within cysts in the smaller proportion of specimens where this was observed. In control tissues, the expression of P450c17 was localized primarily in theca interna of normal ovarian follicles, in theca-lutein cells of some corpora lutea, but not in granulosa-lutein cells. Testicular interstitial cells and islands of adreno-cortical cells located in the adrenal medulla of the adrenal cortex further established the specificity of the antisera used. These data provided the first substantive evidence that polyhedral cells identified previously in GTCTs by histopathology have the potential to synthesize and secrete androgens, similar to theca interna and theca lutein cells in normal equine ovaries. © 2010 Elsevier Inc.

Estruturas secretoras de Pavonia alnifolia (Malvaceae), uma espécie ameaçada de extinção

Malvaceae shows a rich morphological diversity of secretory structures, which are of great ecological and taxonomical relevance. Nonetheless, until the present moment, studies on the secretory structures of the studied species were not found. Pavonia alnifolia A.St.-Hil. is endangered species of extinction with restricted distribution within the restingas of Rio the Janeiro and Espírito Santo, Brazil. The species were collected from the former and usual techniques on plant anatomy and histochemistry were performed. Anatomical and histochemical studies of the secretory structures of Pavonia alnifolia are showed in this work. The presence of external and internal secretory structures of mucilage in many organs, idioblasts of phenolic and lipid substances and floral nectaries what is a very important adaptative survival mechanism of the species in the restinga environment. The secretion produced by nectaries is envolved with maintenance of interations with visiting insects, what constitutes a good model to experimental studies with an ecological approach.

Histochemical and ultrastructural analysis of hepatic glycogen and collagen fibers in alloxan-induced diabetic rats submitted to long-term physical training

Alterations in liver functions are common among diabetic patients, and many symptoms in the liver have been reported, including changes in glycogen stores and in the amount of collagen fibers. The practice of physical training and its morphological effects in this organ, however, are scarcely studied. In order to observe the morphological effects of alloxan-induced diabetes and the alterations arising from the practice of long-term chronic physical training in the liver, samples were collected and processed, and then analyzed by means of the histochemical techniques Periodic Acid-Schiff and Picrosirius-Hematoxylin, and ultrastructural cytochemical test of Afzelius. Through evaluation of the tissue, it was observed a drastic reduction in hepatic glycogen stores of sedentary diabetics, recovered in trained diabetic rats. Furthermore, it was detected a decrease in the content of perisinusoidal collagen fibers in the diabetic liver, also recovered due to the development of a training protocol. On ultrastructural level, cytochemical analysis confirmed the loss of glycogen and the recovery obtained by training. In conclusion, the practice of a long-term chronic physical training protocol may be considered an important assistant in the treatment of diabetes, mitigating the occurrence of possible damages to liver tissue. © 2011 Elsevier Ltd.

Alterations in the fat body cells of rhinocricus padbergi (Diplopoda) resulting from exposure to substrate containing sewage sludge

Abstract The final disposal of residues generated at sewage treatment plants (STPs) has become a major problem for cities, due to the increase in the amount of treated sewage. One of the alternatives for the residue, labeled sewage sludge, is its reuse in agriculture and in degraded soil. However, not all pathogens and metals present in it are eliminated during treatment. Diplopods have been used as bioindicators in ecotoxicological tests as they are constantly in close contact with the soil. Owing to this fact, the purpose of this study was to expose specimens of the diplopod Rhinocricus padbergi to substrate containing sewage sludge collected at STPs to analyze morphological alterations in their parietal and perivisceral fat body, where substances are stored. The exposures were held for 7, 15, or 90 days at different concentrations of sewage sludge (control, 1%, 10%, and 50%). The parietal fat body showed no alterations in any of the three exposure periods or concentrations. Alterations in the perivisceral fat body were observed for all exposure periods. According to the results, we suggest that the sludge used has toxic agents responsible for changing the animal's perivisceral fat body. © 2012 Microscopy Society of America.

Fluazuron-induced morphophysiological changes in the cuticle formation and midgut of Rhipicephalus sanguineus Latreille, 1806 (Acari: Ixodidae) nymphs

The present study demonstrated the effects of the arthropod growth regulator, fluazuron (Acatak®), in the formation of the integument and digestive processes of Rhipicephalus sanguineus nymphs fed on rabbits treated with different doses of this chemical acaricide. For this, three different doses of fluazuron (20, 40, or 80 mg/kg) were applied pour on to the hosts (groups II, III, and IV), as well as distilled water to the control group. On the first day after treatment (24 h), the hosts were artificially infested with R. sanguineus nymphs. After full engorgement (7 days), the nymphs were removed, placed on labeled Petri dishes, and kept in biochemical oxygen demand incubator for 7 days. The engorged nymphs were then taken for morphological, histochemical, and histological analyses. The results showed the occurrence of cytological, morphohistological, and histochemical alterations in the integument and midgut of nymphs from all the different treated groups. These alterations occurred at cuticular level in the subdivisions of the cuticle, related to the size of the digestive cells, amount of accumulated blood elements, and digestive residues, as well as the presence of vacuoles in the cytoplasm of the digestive cells. Thus, this study demonstrated that fluazuron acts on the integument and midgut cells of R. sanguineus nymphs fed on treated rabbits and pointed out the possibility of the use of this chemical - which is more specific, less toxic, and less harmful to the environment and nontarget organisms - in the control of R. sanguineus, at least in the nymphal stage of its biological cycle. © 2012 Springer-Verlag.

Primordial germ cells (spermatogonial stem cells) of bullfrogs express sex hormone-binding globulin and steroid receptors during seasonal spermatogenesis

In vertebrate species, testosterone seems to inhibit spermatogonial differentiation and proliferation. However, this androgen can also be converted, via aromatase, into estrogen which stimulates spermatogonial differentiation and mitotic activity. During seasonal spermatogenesis of adult bullfrogs Lithobates catesbeianus, primordial germ cells (PGCs) show enhanced testosterone cytoplasm immunoexpression in winter; however, in summer, weak or no testosterone immunolabelling was observed. The aim of this study was to confirm if PGCs express stem cell markers-alkaline phosphatase (AP) activity and GFRα1 (glial-cell-line-derived neurotrophic factor)-and verify whether testosterone is maintained in these cells by androgen receptors (ARs) and/or sex hormone-binding globulin (SHBG) in winter. Furthermore, regarding the possibility that testosterone is converted into estrogen by PGCs in summer, the immunoexpression of estrogen receptor (ER)β was investigated. Bullfrog testes were collected in winter and in summer and were embedded in glycol methacrylate for morphological analyses or in paraffin for the histochemical detection of AP activity. GFRα1, AR, SHBG and ERβ expression were detected by Western blot and immunohistochemical analyses. The expression of AP activity and GFRα1 in the PGCs suggest that these cells are spermatogonial stem cells. In winter, the cytoplasmic immunoexpression of ARs and SHBG in the PGCs indicates that testosterone is maintained by these proteins in these cells. The cytoplasmic immunoexpression of ERβ, in summer, also points to an ER-mediated action of estrogen in PGCs. The results indicate a participation of testosterone and estrogen in the control of the primordial spermatogonia during the seasonal spermatogenesis of L. catesbeianus. © 2012 S. Karger AG, Basel.

Side-effects of thiamethoxam on the brain andmidgut of the africanized honeybee Apis mellifera (Hymenopptera: Apidae)

The development of agricultural activities coincides with the increased use of pesticides to control pests, which can also be harmful to nontarget insects such as bees. Thus, the goal of this work was assess the toxic effects of thiamethoxam on newly emerged worker bees of Apis mellifera (africanized honeybee-AHB). Initially, we determined that the lethal concentration 50 (LC50) of thiamethoxam was 4.28 ng a.i./μL of diet. To determine the lethal time 50 (LT50), a survival assay was conducted using diets containing sublethal doses of thiamethoxam equal to 1/10 and 1/100 of the LC50. The group of bees exposed to 1/10 of the LC50 had a 41.2% reduction of lifespan. When AHB samples were analyzed by morphological technique we found the presence of condensed cells in the mushroom bodies and optical lobes in exposed honeybees. Through Xylidine Ponceau technique, we found cells which stained more intensely in groups exposed to thiamethoxam. The digestive and regenerative cells of the midgut from exposed bees also showed morphological and histochemical alterations, like cytoplasm vacuolization, increased apocrine secretion and increased cell elimination. Thus, intoxication with a sublethal doses of thiamethoxam can cause impairment in the brain and midgut of AHB and contribute to the honeybee lifespan reduction. © 2013 Wiley Periodicals, Inc.

Effect of ricinoleic acid esters from castor oil (Ricinus communis) on the oocyte yolk components of the tick Rhipicephalus sanguineus (Latreille, 1806) (Acari: Ixodidae)

Rhipicephalus sanguineus are bloodsucking ectoparasites, whose main host is the domestic dog, thus being present in urban areas and closely located to people. Eventually, this tick species parasitize humans and can become a potential vector of infectious diseases. Methods to control this type of pest have been the focus of many research groups worldwide. The use of natural products is increasingly considered nowadays, due to the low toxicity levels to the host and low waste generation to the environment. This study tested the effect of ricinoleic acid esters from castor oil (as an potential acaricide) on the reproductive system of R sanguineus females, more specifically on the vitellogenesis process. For this, two groups were established: the control group (CG) and the treatment group (TG) with five rabbits in each (New Zealand White), used as hosts. NaCl and ester were added to rabbits' food and offered to the hosts. After full engorgement, the females were collected and had their ovaries extracted. The ticks ovaries were submitted to histochemical techniques so the effects of esters could be observed over polysaccharides, proteins and lipids yolk. Changes in the deposition of yolk components were observed. This caused modifications on elements of polysaccharide origin and on glycoprotein compounds, interfering in the final yolk synthesis and compromising the development of the future embryo. © 2012.

Cellular responses in the Malpighian tubules of Scaptotrigona postica (Latreille, 1807) exposed to low doses of fipronil and boric acid

Studies of sub-lethal effects of pesticide residues on stingless bees are scarce and morphological analysis of organs would add information to toxicological analysis in order to clarify the continuous exposure of Scaptotrigona postica to insecticides. The aim of this study was to evaluate the morphology and histochemistry of the Malpighian tubules (excretory organ) of S. postica exposed to fipronil or boric acid to detect cellular responses that indicate toxicity or adaptative mechanisms to stress induced by exposure of worker bees to low doses of these chemical compounds. Newly emerged bees were submitted to toxicological bioassays and morphological analyses by optical microscopy and Transmission Electron Microscopy, as well as histochemical methods, were performed to detect proteins and glycoconjugates. Additionally, immunohistochemical detection of DNA fragmentation and HSP70 (70-kDa Heat shock protein) were performed to detect cell death and stress response, respectively. Statistical analysis, for the bioassays conducted with ingestion of contaminated diet with boric acid at 0.75% (w/w) or with fipronil at 0.1μg/kg of food, showed that the survival of bees that ingested the contaminated diets were significantly different to the survival rate presented by the control group (P<0.0001). Although some characteristics indicative of initiation of cell death were observed, the cells remained metabolically active in the processes of excretion and inactivation of chemical compounds. The data from this study reinforce the importance of research on sublethal effects of low doses of pesticides on bees in an attempt to assess a possible realistic dose and evaluate the risk assessment of stingless bee S. postica foraging in the vicinity of cultivated fields and/or in green urban areas. © 2013 Elsevier Ltd.

Effects of sublethal dose of fipronil on neuron metabolic activity of africanized honeybees

Fipronil is a neurotoxic insecticide that inhibits the gamma-aminobutyric acid receptor and can affect gustative perception, olfactory learning, and motor activity of the honeybee Apis mellifera. This study determined the lethal dose (LD50) and the lethal concentration (LC50) for Africanized honeybee and evaluated the toxicity of a sublethal dose of fipronil on neuron metabolic activity by way of histochemical analysis using cytochrome oxidase detection in brains from worker bees of different ages. In addition, the present study investigated the recovery mechanism by discontinuing the oral exposure to fipronil. The results showed that mushroom bodies of aged Africanized honeybees are affected by fipronil, which causes changes in metabolism by increasing the respiratory activity of mitochondria. In antennal lobes, the sublethal dose of fipronil did not cause an increase in metabolic activity. The recovery experiments showed that discontinued exposure to a diet contaminated with fipronil did not lead to recovery of neural activity. Our results show that even at very low concentrations, fipronil is harmful to honeybees and can induce several types of injuries to honeybee physiology. © 2012 Springer Science+Business Media New York.

A useful panel for the diagnosis of Hirschsprung disease in rectal biopsies: calretinin immunostaining and acetylcholinesterase histochesmistry

The pathological evaluation of rectal biopsies for the diagnosis of Hirschsprung disease has been a challenging issue. We analyzed prospectively the usefulness of calretinin immunostaining and acetylcholinesterase (AChE) histochesmistry in rectal biopsies for the diagnosis of Hirschsprung disease. Frozen tissue samples from 43 patients were used for AChE histochemistry and paraffin-embedded sections for calretinin immunohistochemistry and conventional histology (hematoxylin and eosin [H&E]). Activity for AChE, was demonstrated in 13 of 43 cases, and the absence of immunoreactivity for calretinin was observed in 14 of 43 cases. Conventional histology (H&E) did not reveal ganglion cells in 24 of 43 cases. The results on calretinin were in good agreement with AChE according to the κ index (0.946; P < .001) and presented significantly higher specificity (96.7 × 63.3; P < .002) and accuracy (97.6 × 74.4; P < .003) when compared with conventional histology (H&E). The final diagnosis of Hirschsprung disease was confirmed in 13 of 43 patients who were submitted to surgical treatment. The results of the present study indicate that calretinin can be a good tool in ruling out the diagnosis of Hirschsprung disease, by showing positive staining in ganglion cells and intrinsic nerve fibers, whereas AChE is useful in confirming the diagnosis of Hirschsprung disease, by revealing activity of this enzyme in hypertrophied nerve fibers. The association between calretinin and AChE can be a useful panel for the histopathologic evaluation of rectal biopsies for the diagnosis of Hirschsprung disease. © 2013 Elsevier Inc. All rights reserved.