Morphological and autoradiographic studies on the corneal and limbal epithelium of rabbits

The investigation was centered on the morphological features of the conjunctiva-cornea transition (limbus) of the rabbit eye and the proliferative behavior of its epithelium. The eyes were processed for examination with light and electron microscopy, as well as for autoradiography after intravitreal injection of [H-3]thymidine ([H-3]TdR). At the sites of extraocular muscle insertion, the vascularization of the stroma extended to the peripheral cornea, and the limbal epithelium was thin with its basal stratum made up by clear cuboidal cells. In between the muscle insertions, the cuboidal clear cells, as well as the stroma blood vessels; were scarce. At the light microscope level, the basement membrane was distinct in the cornea but not in the limbus or the conjunctiva. Autoradiographs demonstrated that, at the limbus, the basal cells migrated very quickly to the suprabasal region and remained there up to the 28-day interval. Labeled cells were identified in all epithelial layers of the cornea, including the basal one, at 21 and 28 days but not in the limbal basal clear cells. The rate of renewal of conjunctival epithelium was similar to that observed for the transition with scarce clear cells. The high-resolution autoradiographs demonstrated that the basal cuboidal clear limbal cells exhibit a quick renewal and that they are not label-retaining cells. These latter ones were detected all over the corneal epithelium and in the suprabasal layers of the limbus up to 28 days, in physiological conditions, without the need of stimulation by damage to the corneal epithelium.

Evaluation of erythrocyte dysmorphism by light microscopy with lowering of the condenser lens: A simple and efficient method

Aim: To demonstrate that the evaluation of erythrocyte dysmorphism by light microscopy with lowering of the condenser lens (LMLC) is useful to identify patients with a haematuria of glomerular or non-glomerular origin. Methods: A comparative double-blind study between phase contrast microscopy (PCM) and LMLC is reported to evaluate the efficacy of these techniques. Urine samples of 39 patients followed up for 9 months were analyzed, and classified as glomerular and non-glomerular haematuria. The different microscopic techniques were compared using receiver-operator curve (ROC) analysis and area under curve (AUC). Reproducibility was assessed by coefficient of variation (CV). Results: Specific cut-offs were set for each method according to their best rate of specificity and sensitivity as follows: 30% for phase contrast microscopy and 40% for standard LMLC, reaching in the first method the rate of 95% and 100% of sensitivity and specificity, respectively, and in the second method the rate of 90% and 100% of sensitivity and specificity, respectively. In ROC analysis, AUC for PCM was 0.99 and AUC for LMLC was 0.96. The CV was very similar in glomerular haematuria group for PCM (35%) and LMLC (35.3%). Conclusion: LMLC proved to be effective in contributing to the direction of investigation of haematuria, toward the nephrological or urological side. This method can substitute PCM when this equipment is not available.

Characteristics of Filiform, Fungiform and Vallate Papillae and Surface of Interface Epithelium-Connective Tissue of the Maned Sloth Tongue Mucosa (Bradypus torquatus, Iliger, 1811): Light and Scanning Electron Microscopy Study

The study of lingual surfaces and the surface of interface epithelium-connective tissue of the tongue of Bradypus torquatus was performed by employing the light and scanning electron microscopy (SEM) techniques. The results revealed that the rostral part of the tongue presents a round apex and covered by filiform and fungiform lingual papillae and a ventral smooth surface. It was observed that the epithelial layer of the dorsal surface possesses the basal, spinosum, granular and cornified epithelial cells. The lamina propria is characterized by a dense connective tissue forming the long, short and round papillae. Numerous typical filiform papillae are located especially in the rostral part intermingled for few fungiform papillae, which were revealed in three-dimensional SEM images. Usually, the fungiform papillae are located in the border of rostral apex of the tongue exhibiting the rounded form. They are covered by keratinized epithelial cells. In the fungiform papillae, several taste pores were observed on the surface. The vallate papillae presented numerous taste buds in the wall of epithelial cells, being that the major number of taste buds is located on the superior half of vallate papilla. The taste pores are surrounded by several laminae of keratinized epithelial cells. The samples treated with NaOH solution and examined by SEM revealed, after removal of the epithelial layer, the dense connective core in original disposition, presenting different sizes and shapes. The specimens stained with Picrosirius and examined by polarized light microscopy revealed the connective tissue, indicating the collagen fibres type I and type III.

Redescription of Amblyomma varium Koch, 1844 (Acari : Ixodidae) based on light and scanning electron microscopy

Amblyomma varium Koch, 1844 is a Neotropical tick, known as the `sloth`s giant tick`, with records from southern Central America to Argentina. It is found almost exclusively on mammals of the families Bradypodidae and Magalonychidae (Xenarthra). Differences exist in discussions with regard to the dentition of the female hypostome being either 3/3 or 4/4. The male was also originally described as having a short spur on coxa IV, but some specimens recently collected from different Brazilian localities have this spur three times longer. These differences beg the question of whether there is more than one species included under this taxon. In order to answer this question and to clarify the taxonomic characters of this species, 258 adult specimens were examined, and a redescription of male and female based on light and scanning electron microscopy is provided. In addition, DNA was extracted from males with either a long or a short spur on coxa IV to help settle this question for future investigations on their taxonomy. The morphological study showed that the dental formula pattern for males and females is 3/3 and 4/4, respectively. When sequenced, the 12 S rDNA genes of both A. varium males with long and short spurs on coxa IV were found to be identical, indicating that the length of the spurs on coxa IV is likely to be an intraspecifically polymorphic character of this species.

Amitriptyline and Acute Inflammation: A Study Using Intravital Microscopy and the Carrageenan-Induced Paw Edema Model

Background/Aims: Antidepressants are reported to exhibit antiinflammatory effects. However, mechanisms involved in this action have not been elucidated. Thus, the objectives of the present study were (a) to evaluate the effects of amitriptyline on the acute inflammatory process, and (b) to investigate the participation of alpha(1)-adrenergic receptors and glucocorticoids as possible mechanisms implicated in the amitriptyline action on inflammation. Methods and Results: Single and multiple doses of amitriptyline were administered to rats submitted to the carrageenan-induced paw edema model. The results showed a significant antiedematous reaction to amitriptyline, mainly when administered at each elimination half-life. The next step was to evaluate its effects on leukocyte behavior, using intravital microscopy. Amitriptyline produced a significant effect on leukocyte behavior. To investigate possible mechanisms involved, a glucocorticoid receptor antagonist (RU-486) and an alpha(1)-adrenergic receptor antagonist (prazosin) were used. RU-486 administration lacked the ability to decrease the amitriptyline antiinflammatory effects in the carrageenan-induced paw edema model. Prazosin pretreatment potentiated the amitriptyline antiinflammatory effect without presenting an effect per se. Conclusion:The present study shows the ability of amitriptyline to decrease edema and affect leukocyte behavior in an acute inflammatory process; and, for the first time to our knowledge, we suggest the involvement of alpha(1)-adrenoceptors in the antiinflammatory effects of amitriptyline. Copyright (C) 2010 S. Karger AG, Basel

The influence of erbium:yttrium-aluminum-garnet laser ablation with variable pulse width on morphology and microleakage of composite restorations

The objective of this study was to evaluate the influence of various pulse widths with different energy parameters of erbium:yttrium-aluminum-garnet (Er:YAG) laser (2.94 mu m) on the morphology and microleakage of cavities restored with composite resin. Identically sized class V cavities were prepared on the buccal surfaces of 54 bovine teeth by high-speed drill (n = 6, control, group 1) and prepared by Er:YAG laser (Fidelis 320A, Fotona, Slovenia) with irradiation parameters of 350 mJ/ 4 Hz or 400 mJ/2 Hz and pulse width: group 2, very short pulse (VSP); group 3, short pulse (SP); group 4, long pulse (LP); group 5, very long pulse (VLP). All cavities were filled with composite resin (Z-250-3 M), stored at 37A degrees C in distilled water, polished after 24 h, and thermally stressed (700 cycles/5-55A degrees C). The teeth were impermeabilized, immersed in 50% silver nitrate solution for 8 h, sectioned longitudinally, and exposed to Photoflood light for 10 min to reveal the stain. The leakage was evaluated under stereomicroscope by three different examiners, in a double-blind fashion, and scored (0-3). The results were analyzed by Kruskal-Wallis test (P > 0.05) and showed that there was no significant differences between the groups tested. Under scanning electron microscopy (SEM) the morphology of the cavities prepared by laser showed irregular enamel margins and dentin internal walls, and a more conservative pattern than that of conventional cavities. The different power settings and pulse widths of Er:YAG laser in cavity preparation had no influence on microleakage of composite resin restorations.

Micromorphology of Resin-Dentin Interfaces Using One-Bottle Etch&Rinse and Self-Etching Adhesive Systems on Laser-Treated Dentin Surfaces: A Confocal Laser Scanning Microscope Analysis

Background and Objectives: This study evaluated the hybrid layer (HL) morphology created by three adhesive systems (AS) on dentin surfaces treated with Er:YAG laser using two irradiation parameters. Study Design: Occlusal flat dentin surfaces of 36 human third molars were assigned into nine groups (n = 4) according to the following ASs: one bottle etch&rinse Single Bond Plus (3M ESPE), two-step Clearfil Protect Bond (Kuraray), and all-in-one S3 Bond (Kuraray) self-etching, which were labeled with rhodamine B or fluorescein isothiocyanate dextran and were applied to dentin surfaces that were irradiated with Er:YAG laser at either 120 (38.7 J/cm(2)) or 200 mJ/pulse (64.5 J/cm(2)), or were applied to untreated dentin surfaces (control group). The ASs were light-activated following MI and the bonded surfaces were restored with resin composite Z250 (3M ESPE). After 24 hours of storage in vegetable oil, the restored teeth were vertically, serially sectioned into 1-mm thick slabs, which had the adhesive interfaces analyzed with confocal laser microscope (CLSM-LSM 510 Meta). CLSM images were recorded in the fluorescent mode from three different regions along each bonded interface. Results: Non-uniform HL was created on laser-irradiated dentin surfaces regardless of laser irradiation protocol for all AS, while regular and uniform HL was observed in the control groups. ""Stretch mark""-like red lines were found within the HL as a result of resin infiltration into dentin microfissures, which were predominantly observed in 200 mJ/pulse groups regardless of AS. Poor resin infiltration into peritubular dentin was observed in most regions of adhesive interfaces created by all ASs on laser-irradiated dentin, resulting in thin resin tags with neither funnel-shaped morphology nor lateral resin projections. Conclusion: Laser irradiation of dentin surfaces at 120 or 200 mJ/pulse resulted in morphological changes in HL and resin tags for all ASs evaluated in the study. Lasers Surg. Med. 42:662-670, 2010. (C) 2010 Wiley-Liss, Inc.

Morphological analysis of human and bovine dentine by scanning electron microscope investigation

Objective: The objective of this study was to compare the superficial morphology of bovine and human sclerotic dentine. Design: For the morphological analysis, bovine (n = 3) and human (n = 3) incisors exhibiting exposed dentine were used. Dentine presented characteristics of sclerosis: brownish, smooth and shiny-the vitreous appearance. The teeth were prepared for assessment on a scanning electron microscope (SEM). Three pre-determined areas of each sample were submitted to SEM. The number of open tubules per area was obtained from the electron micrographs (n = 9 per group) for comparison purposes. Results: The number of open tubules in both species compared were similar (p > 0.05). Human dentine presented 31.89 +/- 23.94 open tubules per area, whereas bovine dentine showed 30.33 +/- 18.14 open tubules per area. Conclusion: Based on the results, we concluded that dentine exposed at the incisal surface of human and bovine teeth presented similar clinical and micro-morphological aspects, represented by surfaces with equivalent numbers of open dentinal tubules. (C) 2007 Elsevier Ltd. All rights reserved.

Effects of Ultramorphological Changes on Adhesion to Lased Dentin-Scanning Electron Microscopy and Transmission Electron Microscopy Analysis

Dentin irradiation with erbium lasers has been reported to alter the composite resin bond to this treated surface. There is still a lack of studies reporting the effect of erbium lasers on dentin organic content and elucidating how laser treatment could interfere in the quality of the resin-dentin interface. This study aimed to evaluate the effect of erbium laser irradiation on dentin morphology and microtensile bond strength (lTBS) of an adhesive to dentin. Seventy-two dentin disks were divided into nine groups (n = 8): G1-Control (600-grit SiC paper); Er:YAG groups: G2-250 mJ/4 Hz; G3-200 mJ/4 Hz; G4-180 mJ/10 Hz; G5-160 mJ/10 Hz; Er, Cr:YSGG groups: G6-2 W/20 Hz; G7-2.5 W/20 Hz; G8-3 W/20 Hz; G9-4 W/20 Hz. Specimens were processed for cross-sectional analysis by scanning electron microscopy (SEM) (n = 3), transmission electron microscopy (TEM) (n = 2), and adhesive interface (n = 3). Forty-five dentin samples (n = 5) were restored and submitted to lTBS testing. ANOVA (alpha = 5%) revealed that G1 presented the highest lTBS values and irradiated groups did not differ from each other. TEM micrographs showed a superficial layer of denatured collagen fibrils. For SEM micrographs, it was possible to verify the laser effects extending to dentin subsurface presenting a rough aspect. Cross-sectional dentin micrographs of this hybridized surface revealed a pattern of modified tags with ringlike structures around it. This in vitro study showed that erbium laser irradiation interacts with the dental hard tissue resulting in a specific morphological pattern of dentin and collagen fibrils that negatively affected the bond strength to composite resin. Microsc. Res. Tech. 74:720-726, 2011. (C) 2010 Wiley-Liss, Inc.

Adhesives bonded to erbium:yttrium-aluminum-garnet laser-irradiated dentin: transmission electron microscopy, scanning electron microscopy and tensile bond strength analyses

The aim of this in vitro study was to investigate the effect of erbium:yttrium-aluminum-garnet (Er:YAG) laser irradiation on dentinal collagen by transmission electron microscopy and to analyze the resin-dentin interface by scanning electron microscopy. A tensile bond strength test was also applied. Specimens from 69 sound human third molars were randomly divided into three groups: control (no laser), and two irradiated groups, laser 250 (250 mJ/2 Hz) and laser 400 (400 mJ/4 Hz). Then, specimens were restored with two adhesive systems, an etch-and-rinse or a self-etch system. Although ultrastructural examination showed a modified surface in the irradiated dentin, there was no statistical difference in bond strength values between the laser groups and controls (P < 0.05). In conclusion, the use of Er:YAG laser for ablating human dentin did not alter the main adhesion parameters when compared with those obtained by conventional methods, thus reinforcing its use in restorative dentistry.

Effect of the Combination of Sodium Hypochlorite and Chlorhexidine on Dentinal Permeability and Scanning Electron Microscopy Precipitate Observation

Introduction: This study compared the combined use of sodium hypochlorite (NaOCl) and chlorhexidine (CXH) with citric acid and CXH on dentinal permeability and precipitate formation. Methods: Thirty-four upper anterior teeth were prepared by rotary instrumentation and NaOCl. The root canal surfaces were conditioned for smear layer removal using 15% citric acid solution under ultrasonic activation and a final wash with distilled water. All teeth were dried, and 30 specimens were randomly divided into three equal groups as follows: positive control group (PC), no irrigation; 15% citric acid + 2% CHX group (CA + CHX); and 1% NaOCl + 2% CHX group (NaOCl + CHX). All roots were immersed in a 0.2% Rhodamine B solution for 24 hours. One-millimeter-thick slices from the cementum-enamel junction were scanned at 400 dpi and analyzed using the software ImageLab (LIDO-USP, Sao Paulo, Brazil) for the assessment of leakage in percentage. For scanning electron microscopy analysis, four teeth, irrigated for NaOCl + CHX samples, were split in half, and each third was evaluated at 1,000x and 5,000x (at the precipitate). Results: Using the analysis of variance test followed by the Bonferroni comparison method, no statistical differences between groups were found when analyzed at the cervical and medium thirds. At the apical third, differences between the PC and NaOCl + CHX (p<0.05) and CA + CHX and NaOCl + CHX could be seen (p < 0.05). Conclusion: The combination of 1% NaOCl and 2% CHX solutions results in the formation of a flocculate precipitate that acts as a chemical smear layer reducing the dentinal permeability in the apical third. (J Endod 2010;36:847-850)

Biofilm Dissolution and Cleaning Ability of Different Irrigant Solutions on Intraorally Infected Dentin

Introduction: The aim of this study was to evaluate the biofilm dissolution and cleaning ability of different irrigant solutions on intraorally infected dentin. Methods: One hundred twenty bovine dentin specimens were infected intraorally by using a removable orthodontic device. Thirty samples were used for each irrigant solution: 2% chlorhexidine and 1%, 2.5%, and 5.25% sodium hypochlorite (NaOCl). The solutions were used for 5, 15, and 30 minutes and at 2 experimental volumes, 500 mu L and 1 mL. The samples were stained by using acridine orange dye before and after the experiments and evaluated by using a confocal microscope. The percentage of biofilm, isolated cells, and noncolonized dentin was measured by using a grid system. Differences in the reduction or increase of the studied parameters were assessed by using nonparametric methods (P < .05). Results: The higher values of biofilm dissolution and noncolonized dentin were found in the 30-minute NaOCl group and in the 5-minute and 15-minute groups of 5.25% NaOCL. The use of 2% chlorhexidine solution did not improve the biofilm dissolution or increase the cleaning of the dentin in comparison with the NaOCl solutions (P < .05). Conclusions: Two percent chlorhexidine does not dissolve the biofilms. Thirty minutes of NaOCl are necessary to have higher values of biofilm dissolution and to increase the cleaning of the dentin independently of the concentration in comparison with the 5-minute and 15-minute contact times. (J Endod 2011;37:1134-1138)

Depth and percentage of penetration of endodontic sealers into dentinal tubules after root canal obturation using a lateral compaction technique: A confocal laser scanning microscopy study

Objective. The aim was to compare the percentage and depth of sealer penetration into dentinal tubules during obturation using Sealer 26, GuttaFlow, or Sealapex in root canals filled with the lateral compaction technique. Study design. Thirty root canals filled with the lateral compaction technique using GuttaFlow (n = 10), Sealapex (n = 10), or Sealer 26 (n = 10) were analyzed using confocal microscopy. The teeth were sectioned at 3 and 5 mm from the apex, and statistical analyses was performed using analysis of variance-Tukey test (P < .05). Results. Sealapex showed the deepest sealer penetration at both levels evaluated (P < .05). No statistically significance was found between Sealer 26 and GuttaFlow at the 3 mm and 5 mm levels. No statistical significance was found in the percentage of penetration around the root canal wall among the 3 sealers evaluated at both levels. Conclusions. Although Sealapex displayed deeper penetration into the dentinal tubules there was no difference in the percentage of adaptation to the root canal walls among the 3 sealers evaluated. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2009; 108: 450-457)

A nanometre-scale non-periodic structural variation in high temperature superconducting ceramics and the implications for properties

Non-periodic structural variation has been found in the high T-c cuprates, YBa2Cu3O7-x and Hg0.67Pb0.33Ba2Ca2Cu3O8+delta, by image analysis of high resolution transmission electron microscope (HRTEM) images. We use two methods for analysis of the HRTEM images. The first method is a means for measuring the bending of lattice fringes at twin planes. The second method is a low-pass filter technique which enhances information contained by diffuse-scattered electrons and reveals what appears to be an interference effect between domains of differing lattice parameter in the top and bottom of the thin foil. We believe that these methods of image analysis could be usefully applied to the many thousands of HRTEM images that have been collected by other workers in the high temperature superconductor field. This work provides direct structural evidence for phase separation in high T-c cuprates, and gives support to recent stripes models that have been proposed to explain various angle resolved photoelectron spectroscopy and nuclear magnetic resonance data. We believe that the structural variation is a response to an opening of an electronic solubility gap where holes are not uniformly distributed in the material but are confined to metallic stripes. Optimum doping may occur as a consequence of the diffuse boundaries between stripes which arise from spinodal decomposition. Theoretical ideas about the high T-c cuprates which treat the cuprates as homogeneous may need to be modified in order to take account of this type of structural variation.

Electron beam current loss at the high-vacuum-high-pressure boundary in the environmental scanning electron microscope

A significant loss in electron probe current can occur before the electron beam enters the specimen chamber of an environmental scanning electron microscope (ESEM). This loss results from electron scattering in a gaseous jet formed inside and downstream (above) the pressure-limiting aperture (PLA), which separates the high-pressure and high-vacuum regions of the microscope. The electron beam loss above the PLA has been calculated for three different ESEMs, each with a different PLA geometry: an ElectroScan E3, a Philips XL30 ESEM, and a prototype instrument. The mass thickness of gas above the PLA in each case has been determined by Monte Carlo simulation of the gas density variation in the gas jet. It has been found that the PLA configurations used in the commercial instruments produce considerable loss in the electron probe current that dramatically degrades their performance at high chamber pressure and low accelerating voltage. These detrimental effects are minimized in the prototype instrument, which has an optimized thin-foil PLA design.