Early iron deficiency produces persistent damage to visual tracts in Wistar rats

In this study, morphological changes in the optic nerve were determined by light microscopy in Wistar rats on an iron-deficient diet for 32 days or for 21 days followed by 10 days on an iron-recovery diet. The morphometric findings showed significantly fewer blood vessels and oligodendrocytes in the iron-deficient rats and iron-recovery rats than in the control group, as well as more astrocytes in the iron-recovery rats. Serum iron levels of the iron-deficient rats were significantly lower than those of the controls. On the other hand, iron-recovery rats had normal serum iron levels, but no change in the abnormal morphology of the myelinated axons and morphometric parameters. Our data indicate that iron is necessary for maintenance of the optic nerve cell structure, and morphological damage from iron-deficiency is not easily reverted by iron reposition.

A morphometric study on the longitudinal and lateral symmetry of the sural nerve in mature and aging female rats

Aging affects peripheral nerve function and regeneration in experimental models but few literature reports deal with animals aged more than one year. We investigated morphological and morphometric aspects of the sural nerve in aging rats. Female Wistar rats 360, 640 and 720 days old were killed, proximal and distal segments of the right and left sural nerves were prepared for light microscopy and computerized morphometry. No morphometric differences between proximal and distal segments or between right and left sides at the same levels were found in all experimental groups. No increase in fiber and axon sizes was observed from 360 to 720 days. Likewise, no difference in total myelinated fiber number was observed between groups. Myelinated fiber population distribution was bimodal, being the 720-days old animals` distribution shifted to the left, indicating a reduction of the fiber diameters. The 9 ratio distribution of the 720-days old animals` myelinated fiber was also shifted to the left, which suggests axonal atrophy. Morphological alterations due to aging were observed, mainly related to the myelin sheath, which suggests demyelination. Large fibers were more affected than the smaller ones. Axon abnormalities were not as common or as obvious as the myelin changes and Wallerian degeneration was rarely found. These alterations were observed in all experimental groups but were much less pronounced in rats 360 days old and their severity increased with aging. in conclusion, the present study indicates that the aging neuropathy present in the sural nerve of female rats is both axonal and demyelinating. (C) 2008 Elsevier B.V. All rights reserved.

Morphology and morphometry of the vagus nerve in male and female spontaneously hypertensive rats

The vagus nerve is an important component of the efferent arm of the baroreflex. Blood pressure levels as well as baroreflex control of circulation are significantly different in male and female spontaneously hypertensive rats (SHR). We proposed to investigate the morphometric differences between genders using the vagus nerve of SHR. Adult animals (20 weeks old) were anesthetized and had their arterial pressure (AP) and heart rate (HR) recorded by a computerized system. The rats were then systemically perfused with a fixative solution and had their cervical vagi nerves prepared for light microscopy. Proximal and distal segments of the left and right vagi nerves were evaluated for morphometric parameters including fascicle area and diameter, myelinated fiber number, density, area and diameter. Comparisons were made between sides and segments on the same gender as well as between genders. Differences were considered significant when p<0.05. Male SHR had significantly higher AP and HR. Morphometric data showed no differences between the same levels of both sides and between segments on the same side for male and female rats. In addition, no significant morphometric differences were observed when genders were compared. This is the first description of vagus nerve morphometry in SHR indicating that gender differences in AP and HR cannot be attributed to dissimilarities in vagal innervation of the heart. These data provide a morphological basis for further studies involving functional investigations of the efferent arm of the baroreflex in hypertension. (C) 2007 Elsevier B.V. All rights reserved.

Experimental selective choriocapillaris photothrombosis using a modified indocyanine green formulation

Background: This in vivo study assessed and compared the effectiveness of an aqueous indocyanine green (ICG) formulation (R-ICG) and a lipid ICG formulation (L-ICG) in occluding the rabbit choriocapillaris, and determined the singlet oxygen quantum yields and aggregation properties of both formulations in vitro. Methods: Singlet oxygen production and aggregation were compared. The eye fundus of 30 albino rabbits was irradiated 0-15 min after dye injection using an 810 nm diode laser. Fluorescein angiography and light microscopy were used to evaluate the safety and efficacy of R-ICG and L-ICG. Results: L-ICG decreased the dimerisation constant and the tendency of ICG to form aggregates, and increased the efficiency of ICG in generating singlet oxygen (R-ICG, Phi Delta= 0.120 and L-ICG, Phi Delta= 0.210). Using a 10 mg/kg dose, choriocapillaris occlusion was achieved at a light dose of 35.8 J/cm(2) with L-ICG and 71.6 J/cm(2) with R-ICG with minimal damage to the neurosensory retina. Conclusion: Restrictions to the use of ICG in aqueous solution, low singlet oxygen quantum yields and high aggregation tendency, were overcome with L-ICG. The lower laser irradiance required to obtain choriocapillaris occlusion may suggest that L-ICG is a more potent and selective photosensitiser than R-ICG.

Fine Structure of the Dorsal Surface of Ostrich`s (Struthio camelus) Tongue

The tongue of birds fills the oral cavity and has a beak-like shape. Morphological studies of birds reveal a correlation between the structure of the tongue and the mechanism of food intake and the type of food. However, several studies have shown morphological differences among the tongues of bird species. The aim of this study was to analyze ostrich tongue morphology and ultrastructural features using scanning electron microscopy. Tongues from 12 adult ostriches were examined. Six tongues were sectioned sagittally into lateral and middle portions, fixed in 10% formaldehyde solution, and examined under light microscopy. The other six samples were sectioned longitudinally, and the dorsal and ventral surfaces were separated, Immersion-fixed In modified Karnovsky solution, and examined under scanning electron microscopy. The tongue surface of the ostrich was smooth, without lingual papillae, and covered by stratified non-keratinized epithelium. In the submucosal layer, mucous salivary glands were surrounded by connective-tissue capsules, with septa dividing the glands Into lobes. Numerous salivary gland ducts of different sizes and connective-tissue laminae dividing each opening could be clearly seen in scanning electron microscope Images. The ventral surface had fewer openings than the dorsal surface. In samples treated with NaOH, connective-tissue papillae from the dorsal region were oriented posteriorly.

Placentation in the Amazonian manatee (Trichechus inunguis)

Evidence from several sources supports a close phylogenetic relationship between elephants and sirenians. To explore whether this was reflected in similar placentation, we examined eight delivered placentae from the Amazonian manatee using light microscopy and immunohistochemistry. In addition, the fetal placental circulation was described by scanning electron microscopy of vessel casts. The manatee placenta was zonary and endotheliochorial, like that of the elephant. The interhaemal barrier comprised maternal endothelium, cytotrophoblasts and fetal endothelium. We found columnar trophoblast beneath the chorionic plate and lining lacunae in this region, but there was no trace in the term placenta of haemophagous activity. The gross anatomy of the cord and fetal membranes was consistent with previous descriptions and included a four-chambered allantoic sac, as also found in the elephant and other afrotherians. Connective tissue septae descended from the chorionic plate and carried blood vessels to the labyrinth, where they gave rise to a dense capillary network. This appeared to drain into shorter vessels near the chorionic plate. The maternal vasculature could not be examined in the same detail, but maternal capillaries ran rather straight and roughly parallel to the fetal ones. Overall, there is a close resemblance in placentation between the manatee and the elephant.

PRECLINICAL INVESTIGATION OF THE RETINAL BIOCOMPATIBILITY OF SIX NOVEL VITAL DYES FOR CHROMOVITRECTOMY

Purpose: To investigate the retinal biocompatibility of six novel vital dyes for chromovitrectomy. Methods: An amount of 0.05 mL of 0.5% and 0.05% light green (LG), fast green (FG), Evans blue (EB), brilliant blue (BriB), bromophenol blue (BroB), or indigo carmine (IC) was injected intravitreally in the right eye, whereas in the left eye balanced salt solution was applied for control in rabbits` eyes. Clinical examination, fluorescein angiography, histology with light microscopy, and transmission electron microscopy were performed after 1 and 7 days. Retinal cell layers were evaluated for morphologic alterations and number of cells. The electroretinographic changes were assessed at baseline, 24 hours and 7 days. Results: Fluorescein angiography disclosed hypofluorescent spots only in the 0.5% EB group. Light microscopy and transmission electron microscopy disclosed slight focal morphologic changes in eyes exposed to 0.05% IC, FG, BriB, similar to the control at 1 and 7 days. In the lower dose groups, EB, LG, and BroB caused substantial retinal alterations by light microscopy. At the higher dose, BroB and EB produced diffuse cellular edema and vacuolization within the ganglion cells, bipolar cells, and photoreceptors. FG and IC at 0.5% caused slight retinal alterations similar to balanced salt solution injection. LG at 0.5% caused diffuse vacuolization of bipolar cells after 1 and 7 days. Injection of 0.5% EB caused a significant decrease in neuroretinal cell counts in comparison to control eyes in the 7-day examination (P < 0.05). Electroretinography revealed intermittent prolonged latency and decreased amplitude in eyes injected with 0.5% EB, LG, BriB, and BroB, while at the lower dose, only LG and EB induced few functional changes. Conclusion: The progressive order of retinal biocompatibility, from safest to most toxic, was IC, FG, BriB, BroB, LG, EB.

Evaluation of three different adhesive systems using a bacterial method to develop secondary caries in vitro

Purpose: To assess the effects of three different dental adhesive systems on the formation of secondary root caries, in vitro, with a standardized interfacial gap in a filled cavity model. Methods: 40 sound human molars were selected and randomly assigned to four experimental groups: Clearfil SE Bond (CSEB), Xeno III (X-III), Scotchbond Multi-Purpose Plus (SBMP) and negative control (NC) without an adhesive system. After the standardized Class V cavity preparations on the buccal and lingual surfaces, restorations were placed with resin composite (Filtek Z250) using a standardized interfacial gap, using a 3 x 2 mm piece of 50 mu m metal matrix. The teeth were sterilized with gamma irradiation and exposed to a cariogenic challenge using a bacterial system with Streptococcus mutans. Depth and extension of wall lesions formed and the depth of outer lesions were measured by software coupled with light microscopy. Results: For wall lesion extension the ANOVA test showed differences between groups except between X-HI and SBMP (P= 0.294). The Tukey`s test of confidence intervals indicated smaller values for the CSEB group than for the others. For wall lesion depth the CSEB group also presented the smallest mean values of wall lesion depth when compared to the others (P< 0.0001) for all comparisons using Tukey`s test. Regarding outer lesion depth, all adhesives showed statistically similar behavior. SEM evaluation of the morphologic appearance of caries lesions confirmed the statistical results showing small caries lesion development for cavities restored with CSEB adhesive system, which may suggest that this adhesive system interdiffusion zone promoted a good interaction with subjacent dentin protecting the dental tissues from recurrent caries. (Am J Dent 2010;23:93-97).

Effect of low-intensity laser therapy on mast cell degranulation in human oral mucosa

Little is known about the physiological mechanisms related to low-intensity laser therapy (LILT), particularly in acute inflammation and subsequent wound healing. The objective of this study was to verify the effect of LILT on mast cell degranulation. Epulis fissuratum tissues from eight patients were used. One part of the lesion was irradiated with an AsGaAl laser (lambda = 670 nm, 8.0 J/cm(2), 5 mW, 4 min). The other part was not irradiated. Then, the specimens were immediately removed, fixed and examined by light microscopy. The number of mast cells was similar in laser-treated samples when compared with non-irradiated specimens. The degranulation indexes of the mast cells observed in the irradiated samples were significantly higher than those of controls (P < 0.05). LILT with the parameters used increased the number of degranulated mast cells in oral mucosa.

Polysaccharide fraction of Agaricus brasiliensis avoids tumor-induced IL-10 production and changes the microenvironment of subcutaneous Ehrlich adenocarcinoma

Subcutaneous Ehrlich tumor-bearing mice were treated with in situ inoculation of a P-glucan-rich extract of Agaricus brasiliensis (ATF), which reduced tumor growth. Histopathological analysis showed that the tumor masses of control mice (Ehr) presented giant tumor cells and many mitotic figures whereas the tumor tissue obtained from ATF-treated animals (Ehr-ATF) presented a lower frequency of both mitotic and giant cells, associated with a higher frequency of apoptotic cells than Ehr. Analysis of the lymphoproliferative activity of spleen cells showed that the treatment had a suppressive rather than a stimulatory effect. Spleen cells of the Ehr group produced higher in vitro levels of IL-10 than normal controls and this occurrence was partially avoided by treatment with ATF. Analysis of cytokine production by tumor-infiltrating cells (ELISpot) showed that ATF induced a higher number of IFN-gamma-producing cells at 7 and 14 days as well as reduction of IL-10-secreting cells at the latter time. Confocal microscopy analysis showed higher intensity of labeling of CD4+ and Mac-3+ cells in ATF-treated mice. Analysis of in situ expression of angiogenic growth factors showed a slight decrease of FGF-2 mRNA in Ehr-ATF animals (7th day) but not of VEGF-A or TGF-beta expression. This fraction could not directly lyse either lymphocytes or tumor cells and we speculate that antitumor effect of ATF could be due to induction of a selective migration of immunocompetent cells from the spleen to the tumor site and to the switch of cytokine production. (C) 2009 Elsevier Inc. All rights reserved.

Biocompatibility evaluation of alendronate paste in rat`s subcutaneous tissue

Alendronate is a known inhibitor of root resorption and the development of alendronate paste would enhance its utilization as intracanal medication. Therefore, this study aimed to investigate the biocompatibility of experimental alendronate paste in subcutaneous tissue of rats, for utilization in teeth susceptible to root resorption. The study was conducted on 15 male rats, weighing similar to 180-200 grams. The rats` dorsal regions were submitted to one incision on the median region and, laterally to the incision, the subcutaneous tissue was raised and gently dissected for introduction of two tubes, in each rat. The tubes were sealed at one end with gutta-percha and taken as control. The tubes were filled with experimental alendronate paste. The animals were killed at 7, 15 and 45 days after surgery and the specimens were processed in laboratory. The histological sections were stained with hematoxylin-eosin and analyzed by light microscopy. Scores were assigned to the in. ammatory process and statistically compared by the Tukey test (P < 0.05). Alendronate paste promoted severe inflammation process at 7 days, with statistically significant difference compared to the control (P < 0.05%). However, at 15 days, there was a regression of in. ammation and the presence of connective tissue with collagen fibers, fibroblasts and blood vessels was observed. After 45 days, it was observed the presence of well-organized connective tissue, with collagen fibers and fibroblasts, and few in. ammatory cells. No statistical difference was observed between the control and experimental paste at 15 and 45 days. The experimental alendronate paste was considered biocompatible with subcutaneous tissue of rat.

Effects of Green Tea Use on Wound Healing

Green tea, a product from Camellia sinensis, consists of over 200 componentes. The most known are the catechins, ou polyphenolic compounds, or flavonoids, but it contains also polysacharide conjugates, amino acids, caffeine and vitamins. Studies have suggested that the regular consumption of green tea reduces the risk of cancer, protecting agains initial events and progression of the disease, may act as antioxidant, has bactericidal properties, and that green tea consumption may be an adjuvant in the treatment of diabetes mellitus, hypertension and hypercholesterolemia. Our experimental study was carried out with male Wistar rats, separated in two groups, experimental and control. The animals in control group were given water ad libitum, and the animals in the experimental group received green tea instead of water. After 2 weeks of experimental period, all the animals, suffered surgical wounds on the dorsum. The animals were sacrificed on I, 3 and 7 days after surgery. Skin samples were used for light microscopy evaluation. Our results allowed us to observe that the experimental group (green tea drinking) presented accelerated epithelial neformation on day 3 after surgery, when epithelial neoformation is in the initial phases. The surgical areas presented 48.20% X 27.32% epithelial neoformation for green tea group and their controls respectivelly at this time. The results of the present study, along with other information about green tea in the literature, strongly suggests that regular use of green tea may be beneficial in surgery situations, when fast epithelial neoformation is desirable.

The role of dentists in-diagnosing osteogenesis imperfecta in patients with dentinogenesis imperfecta

Background. Osteogenesis imperfecta (OI), also known as ""brittle bone disease,"" can be difficult to diagnose in its mild form. The authors describe a clinical case of a diagnosis of dentinogenesis imperfecta (DI), In which a literature review combined with an analysis of dental alterations led to indications of OI involvement. Case Description. Since DI can be associated with OI, the authors reviewed correlated studies and obtained a new medical history from the patient. They then conducted a radiographic and clinical examination of the dentition and submitted an affected third molar to scanning electron microscopy analysis. They compared their findings with descriptions of OI type I dental alterations in the literature and confirmed their diagnosis by means of a medical evaluation. Clinical Implications. In cases in which DI is diagnosed, patients should be examined carefully and the occurrence of OI should be considered `since, in its mild form, it might be misdiagnosed.

Dental erosion in asthma: A case-control study from south east Queensland

Background: Asthma medication places patients at risk of dental erosion by reducing salivary protection against extrinsic or intrinsic acids. But patterns of lesions in asthmatics may differ from patterns in non-asthmatics, because gastro-oesophageal reflux (GOR) is found in 60 per cent of asthmatics. Methods: The lesions in 44 asthma cases were compared to those of age and sex match controls with no history of asthma or medications drawn from the dental records of 423 patients referred concerning excessive tooth wear. The subjects were 70 males age range 15 to 55 years and 18 females age range 18 to 45. Anamnestic clinical data were compared between the two groups. Models of all 88 subjects were examined by light microscopy, and wear patterns were recorded on permanent central incisor, canine, premolar and first molar teeth. Results: Clinical differences were a higher incidence of tooth hypersensitivity; xerostomia, salivary gland abnormalities, gastric complaints, and self induced vomiting in the cases. No differences were found between the cases and controls on citrus fruit and acid soft drink consumption. More occlusal erosion sites were found in cases, whereas more attrition sites were found in the controls. There were no significant differences in palatal erosion on maxillary anterior teeth found between cases and controls. Lingual erosion of the mandibular incisors, found only in GOR patients, was not observed. Conclusions: A higher incidence of erosion was found in asthmatics. Gastro-oesophageal reflux symptoms were not associated with the sign of lingual mandibular incisor erosion. The clinical significance is that asthmatics are at risk of dental erosion from extrinsic acid, but GOR does not appear to contribute in a site-specific manner.

Macrophages, myofibroblasts and neointimal hyperplasia after coronary artery injury and repair

Macrophages participate in the restenosis process through the release of cytokines, metalloproteinases and growth factors. Studies of peritoneal granulation tissue suggest that macrophages may be precursors of myofibroblasts. This study examined the contribution of monocyte/macrophage lineage cells to neointimal cellular mass in a porcine model of thermal vascular injury. Thermal coronary artery injury caused medial smooth muscle cell necrosis and transformation of the media into an extracellular matrix barrier. The neointimal hyperplasia that developed over the injury sites was evaluated by light microscopy, electron microscopy and immunohistochemistry. At day 3, blood monocytes were adhered to the vessel wall and infiltrated the fibrotic media. At day 14, 42 +/- 3.9% of neointimal cells had a monocytic nuclear morphology and expressed macrophage-specific antigen SWC3 (identified by monoclonal antibody DH59B). Moreover, 9.2+/-1.8% of neointimal cells co-expressed SWC3 and alpha-smooth muscle actin and had ultrastructural characteristics intermediate between macrophages and myofibroblasts. At day 28, 10.5 +/- 3.5%, of cells expressed SWC3 and 5.2+/-1.8% of cells co-expressed SWC3 and alpha-smooth muscle actin. This study indicates that hematopoietic cells of monocyte/macrophage lineage abundantly populate the neointima in the process of lesion formation and may be precursors of neointimal myofibroblasts after thermal vascular injury. (C) 2002 Elsevier Science Ireland Ltd. All rights reserved.