Vitamin B-12 Supplement Exerts a Beneficial Effect on the Seminiferous Epithelium of Cimetidine-Treated Rats

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

Morphological evidences indicate that the interference of cimetidine on the peritubular components is responsible for detachment and apoptosis of Sertoli cells

Cimetidine, referred as antiandrogenic agent, has caused alterations in the seminiferous tubules, including alterations in the peritubular tissue and death of myoid cells by apoptosis. Regarding the structural and functional importance of the peritubular tissue for the maintenance of Sertoli cells (SC), we purpose to investigate the SC-basement membrane interface, focusing the morphological features of SC and their interaction with the basement membrane in the affected tubules by cimetidine. Ten animals were distributed into two groups, control (CG) and cimetidine (CmG) which received saline solution and 50 mg of cimetidine per kg of body weight, respectively, for 52 days. The testes were fixed, dehydrated and embedded for analyses under light and transmission electron microscopy. Paraffin sections were submitted to the TUNEL method; sections of testes embedded in glycol methacrylate were submitted to PAS method and stained by H&E for morphological and quantitative analyses of Sertoli Cells. In the CmG, the SC nuclei were positive to the TUNEL method and showed typical morphological alterations of cell death by apoptosis (from early to advanced stages). A significant reduction in the number of Sertoli Cells was probably due to death of these cells by apoptosis. A close relationship between SC nuclear alterations (including a high frequency of dislocated nuclei from the basal portion) and damage in the peritubular tissue was observed. The ultrastructural analysis showed a parallelism between the gradual advancement of apoptotic process in SC and detachment of the anchoring sites (hemidesmosomes) of SC plasma membrane from the lamina densa. The presence of portions of lamina densa underlying the detached hemidesmosomes indicates a continuous deposition of lamina densa, resulting in the thickening of the basal lamina. The results indicate a possible disarrangement of the SC cytoskeleton, including the focal adhesion structure. These alterations are related to SC apoptosis and probably result from disturbs induced by cimetidine on the peritubular tissue.

Factors affecting on bond strength of glass fiber post cemented with different resin cements to root canal

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Bond strength of Epiphany (TM) Sealer combined with different adhesive systems photo-activated with LED and QTH

The Epiphany (TM) Sealer is a new dual-curing resin-based sealer and has been introduced as an alternative to gutta-percha and traditional root canal sealers. The canal filling is claimed to create a seal with the dentinal tubules within the root canal system producing a 'monoblock' effect between the sealer and dentinal tubules. Therefore, considering the possibility to incorporate the others adhesive systems, it is important to study the bond strength of the resulting cement. Forty-eight root mandibular canines were sectioned 8-mm below CEJ. The dentine discs were prepared using a tapered diamond bur and irrigated with 1% NaOCl and 17% EDTA. Previous the application Epiphany (TM) Sealer, the Epiphany (TM) Primer, AdheSE, and One Up Bond F were applied to the root canal walls. The LED and QTH (Quartz Tungsten Halogen) were used to photo-activation during 45 s with power density of 400 and 720 mW/cm(2), respectively. The specimens were performed on a universal testing machine at a cross-head speed of 1 mm/min until bond failure occurred. The force was recorded and the debonding values were used to calculate Push-out bond strength. The analysis of variance (ANOVA) and Tukey's post-hoc tests showed significant statistical differences (P < 0.05) to Epiphany (TM) Sealer/Epiphany (TM) Primer/QTH and EpiphanyTM Sealer/AdheSE/QTH, which had the highest mean values of bond strength. The efficiency of resin-based filling materials are dependent the type of light curing unit used including the power density, the polymerization characteristics of these resin-based filling materials, depending on the primer/adhesive used.

Penetration into dentin of sodium hypochlorite associated with acid solutions

Objective. The objective of this study was to evaluate the penetration of 2.5% NaOCl associated with 17.0% EDTA, 1.0% citric acid, and 1.0% peracetic acid into dentin tubules.Study design. The roots of 44 bovine incisors were cross-sectioned and 5-mm-long fragments were produced from their middle thirds. The specimens were instrumented with ProTaper hand files, stained in crystal violet, then sectioned mesiodistally. The buccal fragments were divided into 4 groups (n = 9) and subjected to 2 consecutive 10-minute immersion periods in one of the following acid solutions combined with 2.5% NaOCl: 17.0% EDTA (group 1), 1.0% citric acid (group 2), and 1.0% peracetic acid (group 3). Nine fragments were immersed in 2.5% NaOCl (group 4). The analysis of the penetration of NaOCl solutions into dentin was performed by measuring the depth of crystal violet stain that was bleached using a steromicroscope under x50 magnification. Statistical comparisons were carried out by Kruskal-Wallis and Dunn's tests at the 5% significance level.Results. Group 1 showed less penetration into dentin than group 4 (P < .05). No statistically significant differences were observed among groups 2, 3, and 4 (P > .05).Conclusions. Association of NaOCl with acid solutions did not increase its penetration depth into root dentin. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2011;112:e155-e159)

Apical Sealing Quality of In Vitro Apicectomy Procedures After Using Both Er:YAG and Nd:YAG

The aim of this study was to evaluate the apical sealing of dentinal tubules after root-end surface cutting by using Er:YAG and Nd:YAG lasers. After root-canal instrumentation and filling, apices of 50 extracted maxillary canine human teeth were resected by Er: YAG with 400 mJ, 10 Hz, for 30 sec. The samples were randomly assigned to five groups (n = 10): (GI) treated without root-end cavity, but with Nd: YAG (1.0W, 10 Hz, 20 sec) for dentinal tubules sealing; (GII) treated with root-end cavity without the use of Nd: YAG; (GIII) treated with root-end cavity and Nd: YAG application; (GIV) treated with root-end cavity made by Er: YAG with no focus and without Nd: YAG application; and (GV) treated without root-end cavity and without Nd: YAG application. The root-end cavities were performed by using Er: YAG at 300 mJ, 10 Hz, for 20 sec. Subsequently, all teeth were waterproofed and immersed in 2% methylene blue for 48 h in a vacuum environment. The samples were longitudinally sectioned, and microleakage was measured. ANOVA and the Fisher LSD test showed that GIV was less susceptible to microleakage than were the other groups (p < 0.05). Interestingly, the use of the Er: YAG with no focus showed superior dentinal tubule sealing in comparison with the other groups, even with or without root-end cavity and Nd: YAG application.

Comparative scanning electron microscopic study of the effect of different dental conditioners on dentin micromorphology

This study evaluated comparatively by scanning electron microscopy (SEM) the effect of different dental conditioners on dentin micromorphology, when used according to the same protocol. Forty dentin sticks were obtained from 20 caries-free third human molars and were assigned to 4 groups corresponding to 3 conditioners (phosphoric acid 37%, Clearfil SE Bond and iBond) and an untreated control group. After application of the conditioners, the specimens were immersed in 50% ethanol solution during 10 s, chemically fixed and dehydrated to prepare them to SEM analysis. In the control group, dentin surface was completely covered by smear layer and all dentinal tubules were occluded. In the phosphoric acid-etched group, dentin surface was completely clean and presented exposed dentinal tubule openings; this was the only group in which the tubules exhibited the funnel-shaped aspect. In the groups conditioned with Clearfil SE Bond primer and iBond, which are less acidic than phosphoric acid, tubule openings were occluded or partially occluded, though smear layer removal was observed. SE Bond was more efficient in removing the smear layer than iBond. In the Clearfil SE Bond group, the cuff-like aspect of peritubular dentin was more evident. It may be concluded all tested conditioners were able to change dentin morphology. However, it cannot be stated that the agent aggressiveness was the only cause of the micromorphological alterations because a single morphological pattern was not established for each group, but rather an association of different aspects, according to the aggressiveness of the tested conditioner.

Morphological studies on the heart ventricle of African catfish (Clarias gariepinus)

The histological and ultrastructural characteristics of the heart ventricle in Clarias gariepinus (African catfish) has been studied by light microscopy and transmission electron microscopy. The ventricle of the heart has a saccular shape and the myocardial wall consists of an outer thin compact myocardium and an inner well-developed spongy myocardium. The myocardial layer has small myocytes, interstitial spaces and blood vessels. The myocytes are the major constituents of the ventricular wall. They are long cells, with large nuclei, and predominantly euchromatin. The sarcoplasmic reticulum of the ventricular myocytes consists of a network of tubules and subsarcolemmal cisternae oriented mainly along the longitudinal axis of the myofibrils. In contrast to the ventricular structure of other fish species described in the literature (Greer-Walker et al., 1985 Santer, 1985 Sanchez-Quintana et al., 1995, 1996), the African catfish, a freshwater sedentary fish recently introduced in neotropical climatic environments, showed a saccular ventricle that consisted of two muscle layers, a thin compact layer with large vessels and a developed spongy layer. The ultrastructure of the ventricular myocardium of C.gariepinus is similar to that of other teleosts, inclusive that of fish with other swimming habits.

A histological study of the seminal vesicle of the armoured catfish Corydoras aeneus

Most species of Corydoras exhibited a reproductive behaviour called 'T-position', and exhibited an accessory gland in the male genital tract, called the seminal vesicle. It appeared that both the structure and the composition of the fluid varied considerably between the species investigated. Consequently, different opinions were proposed regarding the possible role of seminal vesicle on this particular reproductive behaviour. Male adults of Corydoras aeneus were collected, anaesthetized, and samples of seminal vesicle were fixed in Bouin's solution. The sections were stained with haematoxylin-eosin and periodic acid Schiff. The seminal vesicle showed a system of anastomosed secretory tubules, forming a vesicular collective network, which gave rise to the vesicular ducts. The latter fused with the testicular efferent ducts and formed the spermatic ducts. Considering this fusion, when the sperm cells reached the spermatic ducts, the fluid produced at the seminal vesicle covered them. Histochemical studies evidenced the presence of neutral and acid glycosaminoglycans in the seminal fluid. Considering the reproductive behaviour of C. aeneus, it is believed that the protection associated with the immobilization of the sperm cells assures the sperm integrity during the passage through female's intestine until fertilization.

Aquaporin 9 (AQP9) localization in the adult dog testis excurrent ducts by immunohistochemistry

Aquaporins (AQPs) are small, intrinsic membrane proteins that are present in many cell types involved in fluid transport. AQP9 is a major apical water channel that is expressed throughout the efferent ducts, epididymis, and vas deferens, as well as in other regions of the human and rodent male reproductive tract. The target of this study was to examine the expression of AQP9 in epithelial cells in the adult dog efferent ducts, epididymis, and vas deferens. Samples of dog male reproductive tract comprising fragments of the testis; initial segment, caput, corpus, and cauda of the epididymis; and vas deferens were obtained from eight adult mongrel dogs. Immunohistochemistry and Western blotting procedures were used to show AQP9 localization and distribution. AQP9 expression was not detected either in dog seminiferous tubules or rete testis. However, apical labeling for AQP9 was detected in the different regions of epididymis and vas deferens, with the reaction being less intense in the caput epididymis. Thus, AQP9 is abundantly expressed in dog male reproductive tract, in which it is an important apical pathway for transmembrane flow of water and neutral solutes.

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.

Morphometric study of Rynchotus rufescens testis throughout the year

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

Morphological aspects of spermatogenic cells at different stages of sexual maturation in black isogenic C57BL/6/Uni mice

In order to study the morphological changes that occur in cells of the testes of isogenic black mouse C57BL/6/Uni into three periods during spermatogenetic used 15 mice divided into 3 groups of 5 animals with 40,50 and 60 days of age. The mice were sacrificed and weighed. Testicles were weighed and measured, and histologically processed and stained with HE, PAS and Masson Massom-H and evaluated under light microscopy. It was observed that group I with 40 days of age in the seminifcrous tubules had a lumen with sparse small amount of interstitial tubular cells. In the seminiferous epithelium type A spermatogonia, intermediate and B were identified, which occupied the compartment adbasal and intermingled with these cells in spermatocytes I in Pachytene and leptotene was observed, whereas in the adluminal compartment Golgi phase spermatids we observed the presence of acrosomal granule. In group II, the cells of the seminiferous epithelium were developed and it was observed in round spermatids cephalic hood phase plus many elongated spermatids in acrosome phase and Sertoli cells. In Group III, 60 days old, it was found that seminiferous epithelium which was of the tubules had elongated spermatids in acrosome phase and maturation, with elongated nuclei and acrosomal system typical of spermiation in the presence of sperm and residual bodies near the tubular lumen. Therefore morphological evolution of germ cell testicular spermatids can be checked and recognized in its four phases: Golgi, cap, acrosome and maturation over the age of the animal.

Structural evaluation of the effects of chronic ethanol ingestion on the testis of Calomys callosus

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

Características ultra-estruturais e diferenciativas das espermátides de piracanjuba (Brycon orbignyanus) durante a espermiogênese

A espermiogênese que ocorre em piracanjuba Brycon orbignyanus pode ser dividida em quatro etapas morfológicas, cujas características principais consistem em reduções dos volumes citoplasmático, nuclear e celular, e compactação da cromatina nuclear das espermátides, sendo que as etapas espermiogenéticas ocorrem simultaneamente. Ao final da espermiogênese, quando as espermátides atingem nível elevado de diferenciação, os núcleos se tornam mais compactos e os citoplasmas se tornam reduzidos. Estas modificações resultam na formação de células altamente diferenciadas, os espermatozóides com cabeça, peça intermediária e flagelo bem definidos. As espermátides e os espermatozóides foram observados em cistos germinativos, mas também podem ser encontrados na luz dos túbulos seminíferos.