Ultrastructural evidences of the occurrence of digestion and absorption of organic solutes in bees ileum (Melipona quadrifasciata anthidioides - Hymenoptera, Apidae)

The ultrastructural aspects of the ileum of Melipona quadrifasciata anthidioides, a stingless bee whose workers obtain their protein requirements from pollen, present morphological evidences of digestion and absorption. These evidences are represented by special relationships between food particles and the bacterial nora present and between their assemblage and the ileum wall, mainly in the ileum three anterior fourths. The apical features of the epithelium also are indicative of organic material absorption.

The effects of ochratoxin/aluminosilicate interaction on the tissues and humoral immune response of broilers

This study aimed to evaluate the effect of dietary ochratoxin, in the presence or absence of aluminosilicate, on the histology of the bursa of Fabricius, liver and kidneys, and on the humoral immune response of broilers vaccinated against Newcastle disease virus. The exposure of birds to 2 p. p. m. ochratoxin, in the presence or absence of aluminosilicate, reduced their humoral immune response and the number of mitotic cells in the bursa. The relative weight of the livers of the birds exposed to this toxin was increased and, microscopically, there was hepatocyte vacuolation and megalocytosis with accompanying hyperplasia of the biliary epithelium. The kidneys showed hypertrophy of the renal proximal tubular epithelium, with thickening of the glomerular basement membrane. Aluminosilicate did not ameliorate the deleterious effects of the ochratoxin.

Morphometric and ultrastructure features of the ventral prostate of rats (Rattus norvegicus) submitted to long-term nicotine treatment

The harmful effects of nicotine on male genital system fertility have been reported in experimental and clinical studies. However, its effects on prostatic cells and glandular pathogenesis remain unclear. The aim of the present study was to analyse the histological, histochemical and ultrastructural alterations, in addition to stereology, of the ventral lobe of the prostate of rats, submitted to chronic nicotine administration, as well as to establish the relationship between these changes and prostate diseases. Twelve male Wistar rats (Rattus norvegicus) were divided into two experimental groups: group I (nicotine) and group II (control). Samples of the ventral prostate were collected, processed and submitted to histological analysis, acid phosphatase histochemistry and ultrastructural analysis by transmission and scanning electron microscopies. The results showed that in the nicotine group, the secretory epithelial cells of the ventral lobe of the prostate were atrophied, and prostatic intraepithelial neoplasia occurred and reduced the expression of acid phosphatase. The disorganisation of organelles involved in the glandular secretory process, accompanied by biomembrane destructuring, was also observed. In conclusion, nicotine causes drastic alterations in the secretory epithelium of the ventral prostate, compromising its function. Furthermore, nicotine also induces premalignant lesions in the prostate gland, thus representing a risk factor in the development of prostate diseases.

The influence of chlorhexidine on the severity of cyclosporin A-induced gingival overgrowth

THE INFLUENCE OF CHEMICAL PLAQUE CONTROL, using topically applied 0.12% chlorhexidine, on the severity of cyclosporin A (CsA)-induced gingival overgrowth (GO) was evaluated. Forty Holtzman rats were divided into four groups: 1) control; 2) cyclosporin A: a 10mg/kg/day subcutaneous dose of CsA; 3) chlorhexidine: 0.12% chlorhexidine (CHX) was applied to the buccal surface of the right mandibular molars; and 4) cyclosporin A/chlorhexidine: a combination of the treatment described for cyclosporin A and chlorhexidine groups. The animals were fed a high sucrose diet during the experiment and were sacrificed after 14 and 21 days. The histometric analysis revealed a significant increase in buccal gingival area in the cyclosporin A group compared to other groups (P < 0.01) after 21 days. The epithelium thickness of the buccal gingiva was significantly increased in the cyclosporin A group, compared to the control group (P < 0.05). The cyclosporin A/chlorhexidine group exhibited statistically significantly lower gingival overgrowth than the cyclosporin A group. These findings, if replicated in human studies, suggest that topically applied 0.12% chlorhexidine may be a valuable measure in the management of cyclosporin-induced gingival overgrowth.

Experimental alcoholism and pathogenesis of prostatic diseases in UChB rats

Previous studies have shown that long-term alcohol treatment has negative effects on prostatic stromal-epithelial interaction. Thus, the aim of the present study was to analyze the histochemical, immunohistochemical and ultrastructural alterations that occur in the prostatic stroma and epithelium of rats submitted to chronic alcohol ingestion and alcohol abstinence, as well as to establish the relationship between these changes and prostatic diseases. Thirty male rats (10 Wistar and 20 UChB rats) were divided into three experimental groups: the control group received tap water, the alcoholic group received ethanol diluted to 10 degrees G.L. for 150 days, and the abstinent group received the same liquid diet as the alcoholic group up to 120 days of treatment and only tap water for 30 days thereafter. At the end of treatment, all animals were sacrificed and the ventral lobe of the prostate was removed and processed for histochemical, immunohistochemical and ultrastructural analyses. In addition, plasma testosterone levels were measured. The results showed, prostatic intraepithelial neoplasia, infolding of the epithelium towards the stroma, stromal hypertrophy and the presence of inflammatory cells in alcoholic animals. In the abstinent group, alterations were noted mainly in the stromal area. In conclusion, ethanol triggers alterations in prostatic epithelial and stromal compartments, affecting the stromal microenvironment and predisposing the organ to pathological processes. (C) 2006 International Federation for Cell Biology. Published by Elsevier Ltd. All rights reserved.

Placentation in the rock cavy, Kerodon rupestris (Wied)

Rock cavies are rodents found in the semi-arid caatinga of Brazil. We studied the structure of the rock cavy placenta by light and transmission electron microscopy. The exchange area of the labyrinth was organized in lobes separated by interlobular areas. The interhaemal barrier was syncytial haemomonochorial. The syncytiotrophoblast had recesses in the basal membrane and some invaginations of the apical membrane, but transtrophoblastic channels could not be found. The interlobular regions comprised syncytiotrophoblast, enclosing maternal venous blood channels, and cytotrophoblast. There was a prominent subplacenta composed of cytotrophoblast and syncytiotrophoblast. Microvilli projected into spaces between the cytotrophoblasts and into lacunae within the syncytiotrophoblast. The yolk sac epithelium exhibited coated pits, endocytotic vesicles and larger vacuoles, consistent with a role in protein uptake from the uterine lumen. Tight junctions between these cells provided a barrier to diffusion by the intercellular route. The reproductive biology of the rock cavy differs from other members of the family, including the guinea pig, but the architecture of the placenta remains remarkably constant. (c) 2004 Elsevier Ltd. All rights reserved.

Testosterone stimulates growth and secretory activity of the female prostate in the adult gerbil (Meriones unguiculatus)

The prostate of the female gerbil (Meriones unguiculatus) is similar to the human female prostate (Skene gland) and, despite its reduced size, it is functional and shows secretory activity. However, virtually nothing is known about its physiological regulation. This study was thus undertaken to evaluate the behavior of the gerbil female prostate in a hyperandrogenic condition. Adult females received subcutaneous injections of testosterone cypionate (1 mg/kg body weight every 48 h) up to 21 days. Circulating levels of testosterone and estradiol were monitored, and the prostate and ovaries subjected to structural and immunocytochemical analyses. The treatment resulted in sustained high levels of circulating testosterone, and caused a transient increase in estradiol. There was an increase in epithelial cell proliferation accompanied by significant reorganization of the epithelium and an apparent reduction in secretory activity, followed by a progressive increase in luminal volume density and accumulation of secretory products. Immunocytochemistry identified the expression of androgen receptor and a prostate-specific antigen (PSA)-related antigen in prostatic epithelial cells. A circulating PSA-related antigen was also found, and its concentration showed strong negative correlation with circulating estrogen. Epithelial dysplasia was detected in the prostate of treated females. Analysis of the ovaries showed the occurrence of a polycystic condition and stromal cell hyperplasia. The results indicate that testosterone has a stimulatory effect on the female prostate, inducing epithelial cell proliferation, differentiation, secretory activity, and dysplasia. The results also suggest that prostatic growth and activity, polycystic ovaries, and ovarian stromal cell hyperplasia are related to a hyperandrogenic condition in females.

Light microscopy and computer three-dimensional reconstruction of the blood capillaries of the enamel organ of rat molar tooth germs

We performed a light microscope and a computer three-dimensional reconstruction study of serial sections of the molar enamel organ of 3- and 5-day-old rats perfused with Indian ink through the arterial system. The tooth germs were fixed in Bouin's solution, embedded in paraffin, sectioned and stained with haematoxylin and eosin. For the three-dimensional reconstruction, light micrographs of the serial sections were digitized, and aligned using the serial EM Align software downloaded from http://synapses.bu.edu/tools/. After alignment, the boundaries of the India-ink-filled blood vessels were manually traced with a mouse using the software IGL trace (version 1.26b), also downloaded from the above website. After tracing, a three-dimensional representation of the blood vessel contours was generated in a VRML format and visualized with the help of the software Cortona Web3D viewer (version 4.0) downloaded from http://www.parallelgraphics.com/products/cortona. Our results showed that in regions where ameloblasts are polarized the capillaries are arranged in three distinct levels: (1) penetrating and leaving capillaries in relation to the outer enamel epithelium; (2) capillaries crossing and branching inside the stellate reticulum; and (3) capillaries branching and anastomosing profusely within the stratum intermedium, thereby forming an extensive capillary plexus intimately associated with the cells of the stratum intermedium. The existence of a conspicuous capillary plexus intermingled with cells of the stratum intermedium, as shown in our results, suggests that some molecules produced by cells of the stratum intermedium could be released into the capillary plexus and thereafter carried to the dental follicle.

Abnormal expression of bcl-2 and bax in rat tongue mucosa during the development of squamous cell carcinoma induced by 4-nitroquinoline 1-oxide

4-Nitroquinoline 1-oxide (4NQO)-induced rat tongue carcinogenesis is a useful model for studying oral squamous cell carcinoma. The aim of this study was to investigate the expression of bcl-2 and bax during tongue carcinogenesis induced by 4NQO. Male Wistar rats were distributed into three groups of 10 animals each and treated with 50 ppm 4NQO solution through their drinking water for 4, 12 or 20 weeks. Ten animals were used as negative control. Although no histological changes were induced in the epithelium after 4 weeks of carcinogen exposure, bcl-2 and bax were over-expressed (P < 0.01) in all layers of the 'normal' epithelium. The expression levels were the same in all layers of epithelium for both the antibodies used (bcl-2 or bax). In dysplastic lesions at 12 weeks following carcinogen administration, the levels of bcl-2 and bax expression did not increase when compared to negative control with the immunoreactivity for bcl-2 being restricted to the superficial layer of epithelium. In well-differentiated squamous cell carcinoma induced after 20 weeks of treatment with 4NQO, bcl-2 was expressed in some cells of tumour islands. on the other hand, immunostaining for bax was widely observed at the tumour nests. The labelling index for bcl-2 and bax showed an increase (P < 0.05) after only 4 weeks of 4NQO administration. In conclusion, our results suggest that abnormalities in the apoptosis pathways are associated with the development of persistent clones of mutated-epithelial cells in the oral mucosa. Bcl-2 and bax expression appears to be associated with a risk factor in the progression of oral cancer.

Paradental cyst: Report of two cases

Background: the paradentat cyst is an odontogenic lesion of inflammatory origin that has few clinical signs and symptoms apart from recurring acute episodes. A well-defined radiolucency associated with the roots or distal to the crown may be seen radiographically. The purpose of this article is to report on different aspects of two cases involving paradental cysts. In the first case, the patient complained about recurring pericoronitis. A semilunar-shaped radiolucency on the distal aspect of the mandibular third molar was noted on the periapical radiograph. In the second case, the patient's main complaint was chronic trauma of the overlying mucosa. Radiographs revealed an enlarged pericoronal space.Methods: In both cases, the mandibular third molar was extracted due to a lack of space. Lesional samples were sent for histopathologic analysis.Results: In the first case, the drainage of cystic fluid and a regular concavity were found during tooth removal. In the second case, a nodular lesion was found adhering to the disto-buccal surface of the tooth arising from the distal wall of a periodontal pocket. The histopathologic analysis revealed a hyperplastic stratified squamous epithelium with arcading lining a fibrous capsule with inflammatory infiltrate, resulting in a final diagnosis of a paradental cyst.Conclusions: the presence of a paradental cyst should be considered when recurrent inflammatory periodontal processes are associated with partially erupted vital teeth, even when characteristic radiographic findings are absent. Definitive diagnosis requires a clinicopathologic correlation incorporating surgical, radiographic, and histologic findings.

ULTRASTRUCTURE OF THE MANDIBULAR GLANDS OF PACHYCONDYLA-STRIATA ANTS (HYMENOPTERA, PONERINAE) .1. WORKERS

The mandibular glands of Pachycondyla striata workers consists of a proximal reservoir and secretory portion. The secretion is transported from the cytoplasm of the secretory cells to reservoir through individual canaliculi which is subdivided into two portions : an intracytoplasmatic and extracellular one. The reservoir consists of an epithelium made up of thin cells has a thick cuticle. The secretory cells showed a large amount of structures forming the citoskeleton always associated with myelin figures.

Verruciform xanthoma of the oral mucosa. Report of four cases and a review of the literature

We present four new cases of verruciform xanthoma (VX) in the oral mucosa and review the literature. Clinical, histological, and immunohistochemical features of four new cases of VX were analysed together with cases found in a review of the literature. Expression of CD-68 was studied by immunohistochemistry. Only 162 cases were reported in the oral mucosa. Ninety were males (55.5%) and 72 were females (44.5%). Mean age was 44.9 years. The majority of cases occurred in masticatory mucosa (69.7%). Our cases exhibited papillary or verrucous proliferation of squamous epithelium associated with hyperparakeratosis and with numerous foamy cells confined to the lamina propria papillae. Foamy cells were positive to CD-68 antibody, showing a macrophagic nature. VX is a rare benign lesion, and is probably inflammatory. However, its aetiology and pathological mechanisms remain unknown. (C) 2001 Elsevier B.V. Ltd. All rights reserved.

Structure and ultrastructure of the ventral prostate of isogenic mice (C57B1/6J) submitted to chronic alcohol ingestion

Morphological and functional alterations caused by chronic alcohol ingestion in testes and accessory sex organs have been studied both in man and in laboratory animals. The aim of the present study was to examine the possible occurrence of deleterious effects of chronic alcohol ingestion on the secretory epithelium of the ventral prostate of mice. Twenty-four adult male C57BL/6J mice were divided into three groups. The alcohol-treated group was allowed to drink only 6% (v/v) ethanol, the isocaloric group received a diet of water/sucrose with a calorie content equivalent to a 6% alcohol solution and the control group received water. Both groups were fed ad libitum with solid Purina rat chow. After 120 days, animals from each group were anesthetized with ethyl ether, weighed and processed for light and transmission electron microscopy. The results demonstrated reduction in the glandular epithelium cell height and disorganization of the Golgi complex. Moreover, abundant membrane-bound structures, most likely representing cytoplasmic material, were observed, as well as accumulation of dense bodies. Statistical analysis showed that bodyweight gain was similar for both groups. In conclusion, chronic alcohol ingestion has harmful effects on the secretory epithelium cells of the ventral lobe of the prostate of mice after 120 days of treatment. (C) 2001 Harcourt Publishers Ltd.

A specialized midgut region in stingless bees (Hymenoptera: Apidae: Meliponinae)

Ultrastructure of the anterior end of the midgut of three Neotropical stingless bees, including an obligate necrophagous species Trigona hypogea, suggests that this midgut region has no role in nutrient absorption because its lumen is reduced by a thick cuticle that lines the outer epithelium of the cardiac valve. A possible involvement of this midgut region in the production of the peritrophic membrane compounds is discussed.

A morphometric ultrastructural study of the seminal vesicle of rats submitted to experimental chronic alcoholism

The effects of chronic alcohol ingestion on the secretory epithelium of the seminal vesicle were studied in rats (Rattus norvegicus). Male adult albino Wistar rats were divided into two groups: alcoholic and control. Tips of the seminal vesicle were removed and prepared for light and electron microscopy. Ultrastructural observations on the epithelial cells of the seminal vesicle showed reduced epithelial cell size, decreased apical secretory vacuoles, irregularly shaped nuclei with deep infoldings, increased lipid droplets and dense bodies, a small number of microvilli covering the cell surface, and signs of degeneration. In addition to the hormonal effects, alcohol may act on the secretory epithelium of the seminal vesicle.