Flavia de Oliveira

Ultrastructural study of the filum terminale and its elastic fibers.

OBJECTIVE:The filum terminale (FT) is a fibrovascular band involved in the pathophysiology of tethered cord syndrome (TCS). Its morphological and ultrastructural properties remain largely unknown even though they are thought to play a role in the generation of TCS in adult patients with normal level conus medullaris. MATERIALS AND METHODS:Twenty fresh adult human cadavers had their fila measured and removed. Transversal and longitudinal sections of the proximal, middle, and distal thirds of FT were submitted to light microscopy analysis with four different techniques. Five fila were selected for longitudinal and transversal scanning electron microscopy analysis. RESULTS:The bulk of the FT is composed of 5- to 20-&mgr;m thick longitudinal bundles of Type 1 collagen separated by 3- to 10-&mgr;m intervals, although capillaries and other elements may be present. A delicate (0.05–1.5 &mgr;m) meshwork of predominantly Type 3 collagen transversal fibers connects these bundles. Abundant longitudinally oriented elastic and elaunin fibers are found inside collagen bundles. A complex tridimensional structure is evidenced on electron microscopy. CONCLUSION:The longitudinal arrangement of collagen bundles and the impressive amount of elastic and elaunin fibers should elicit considerable elastic properties to the FT. An altered elasticity mechanism has been proposed for TCS; further studies are needed with TCS patients to define whether the collagen structure, Type 1/Type 3 proportion, or elastic fiber content are altered, which could lead to new histopathological definitions of TCS, helping neurosurgeons in the difficult management of TCS patients with normal level conus medullaris.

Morphological changes in distant muscle fibers following thermal injury in Wistar rats

PURPOSE Thermal injury causes catabolic processes as the body attempts to repair the damaged area. This study evaluated the effects of a scald injury on the morphology of muscle fibers belonging to a muscle distant from the lesion. METHODS Thirty Wistar rats were divided into control (C) and scalded (S) groups. Group S was scalded over 45% of the body surface, standardized by body weight. Rats in both groups were euthanized at four, seven and 14 days following the injury. The middle portions of the medial gastrocnemius muscles were sectioned, stained with hematoxylin and eosin and Picrosirius, and submitted to histological analysis. RESULTS Control group sections exhibited equidistantly distributed polygonal muscle fibers with peripheral nuclei, characteristic of normal muscle. The injured group sections did not consistently show these characteristics; many fibers in these sections exhibited a rounded contour, variable stain intensities, and greater interfiber distances. A substantially increased amount of connective tissue was also observed on the injured group sections. CONCLUSION This experimental model found a morphological change in muscle distant from the site of thermal injury covering 45% of the body surface.

The connective tissue of the adductor canal – a morphological study in fetal and adult specimens

The adductor canal is a conical or pyramid‐shaped pathway that contains the femoral vessels, saphenous nerve and a varying amount of fibrous tissue. It is involved in adductor canal syndrome, a claudication syndrome involving young individuals. Our objective was to study modifications induced by aging on the connective tissue and to correlate them to the proposed pathophysiological mechanism. The bilateral adductor canals and femoral vessels of four adult and five fetal specimens were removed en bloc and analyzed. Sections 12 µm thick were obtained and the connective tissue studied with Sirius Red, Verhoeff, Weigert and Azo stains. Scanning electron microscopy (SEM) photomicrographs of the surfaces of each adductor canal were also analyzed. Findings were homogeneous inside each group. The connective tissue of the canal was continuous with the outer layer of the vessels in both groups. The pattern of concentric, thick collagen type I bundles in fetal specimens was replaced by a diffuse network of compact collagen bundles with several transversal fibers and an impressive content of collagen III fibers. Elastic fibers in adults were not concentrated in the thick bundles but dispersed in line with the transversal fiber system. A dynamic compression mechanism with or without an evident constricting fibrous band has been proposed previously for adductor canal syndrome, possibly involving the connective tissue inside the canal. The vessels may not slide freely during movement. These age‐related modifications in normal individuals may represent necessary conditions for this syndrome to develop.

The chemopreventive activity of apple against carcinogenesis: antioxidant activity and cell cycle control

Apples and their derivatives are rich in phytochemicals, including flavonoids (catechins, flavonols, quercetin) and phenolic acids (quercetin glycosides, catechin, epicatechin, procyanidins), vitamins, and fibers, that confer an important antioxidant property. Chemoprevention is defined by the use of natural or synthetic agents to interfere with the progression, reverse, or inhibit carcinogenesis, thereby reducing the risk of developing clinically invasive disease. The aim of this article is to present data generated from the use of apples as a chemopreventive agent in carcinogenesis using in-vivo and in-vitro test systems. Apple and its bioactive compounds can exert chemopreventive properties as a result of antioxidant activity and cell cycle control. However, future focus of research on apple such as identifying the specific phytochemical responsible for the anticarcinogenic effect, timing of consumption, and adequate amount of apples to achieve the best preventive effect using human large randomized-controlled trials is needed. Furthermore, animal studies are also relevant for better understanding the role of this fruit in human health as well as modulation of degenerative diseases such as cancer. Therefore, this area warrants further investigation as a new way of thinking, which would apply not only to apples but also to other fruit used as promising therapeutic agents against human diseases.

Peer mentoring program in an interprofessional and interdisciplinary curriculum in Brazil

The Federal University of São Paulo, Baixada Santista Campus was founded in 2006 with five degree‐granting programs in physical education, physiotherapy, nutrition, psychology, and occupational therapy. The guiding principle behind the programs’ educational mission was centered on the development of health care professionals capable of working in interdisciplinary teams with an emphasis on holistic patient care. This pedagogical structure required peer‐mentoring programs in order to integrate different areas of knowledge and to improve learning strategies among new generations of students. The authors’ objective in the present report is to discuss the strategies and activities of the peer‐mentoring program in histophysiology and gross anatomy in an interdisciplinary and interprofessional curriculum. Evaluations by students, mentors and professors are presented, along with a statistical analysis of variance comparing student performance in the module assessments according to their participation in the peer‐mentoring activities. The results demonstrated that students who participated in peer‐mentoring activities enjoyed a higher rate of academic success than those who did not participate. In addition, student and mentor evaluations of the peer mentoring program were highly positive. The program enabled mentors to gain a deeper knowledge of the subjects addressed in the learning modules, as well as to develop intrinsic teaching skills during their time as mentors. In short, the authors believe that the peer‐mentoring program has been validated for its effectiveness in raising student academic performance. Anat Sci Educ 8: 338–347.

Low-level laser therapy modulates musculoskeletal loss in a skin burn model in rats

PURPOSE To investigate the effectiveness of low-level laser therapy (LLLT) on gastrocnemius muscle morphology and Myod immunoexpression in a model of dorsal burn in rats. METHODS Sixteen male Wistar rats were distributed into two groups: control group (CG): rats submitted to scald burn injury without treatment and laser treated group (LG): rats submitted to scald burn injury and treated with laser therapy. Fourteen days post-surgery, gastrocnemius muscle was evaluated being the specimens stained with HE and morphometric data was evaluated. MyoD expression was assessed by immunohistochemistry. RESULTS The results showed that laser treated animals presented more organized tissue morphology compared to the non-treated animals, with a higher number of nucleus in the fibers. Also, the cross sectional area of the fibers and the MyoD immunoexpression in the laser treated groups was higher. CONCLUSION Low-level laser therapy had positive effects on gastrocnemius muscle, improving tissue muscle morphology, increasing cross sectional area and MyoD immunoexpression.

Anacardic Acid from Brazilian Cashew Nut Trees Reduces Dentine Erosion

The aim of this study was to analyze the effect of solutions containing saturated anacardic acid (AA) on dentine erosion in vitro. AA was chemically isolated from natural cashew nutshell liquid obtained by continuous extraction in a Soxhlet extractor and was fully saturated by catalytic hydrogenation. Matrix metalloproteinase 2 (MMP-2) activity, when exposed to buffers containing 100 µmol/l AA, was analyzed using zymography. Bovine root samples were subjected to erosive demineralization (Sprite Zero™, 4 × 90 s/day) and remineralization with artificial saliva between the erosive cycles for 5 days. The samples were treated as follows, after the first and the last acid exposure (1 min; n = 12/group): (1) 100 µmol/l epigallocatechin-3-gallate (EGCG) (positive control); (2) 0.05% NaF; (3) 100 µmol/l saturated AA; (4) saturated AA and EGCG; (5) saturated AA, EGCG and NaF; (6) untreated (negative control). Dentine erosion was measured using a contact profilometer. Two dentine samples from each group were analyzed using scanning electron microscopy. Saturated AA reduced the activity of MMP-2. ANOVA and Tukeys test revealed that all treatments significantly reduced dentine loss compared to the negative control (6.03 ± 0.98 µm). Solutions containing saturated AA (1.97 ± 1.02 µm) showed the greatest reduction in dentine erosion compared to the NaF (3.93 ± 1.54 µm) and EGCG (3.79 ± 0.83 µm) solutions. Therefore, it may be concluded that AA significantly reduces dentine erosion in vitro, possibly by acting as an MMP-2 inhibitor.

The cytotoxic effect of TiF4 and NaF on fibroblasts is influenced by the experimental model, fluoride concentration and exposure time

Objective Titanium tetrafluoride (TiF4) has shown promising effect in preventing tooth lesions. Therefore, we compared the cytotoxicity of TiF4 with sodium fluoride (NaF) (already applied in Dentistry) considering different fluoride concentrations, pH values and experimental models. Materials and methods Step 1) NIH/3T3 fibroblasts were exposed to mediums containing NaF or TiF4 (from 0.15 to 2.45% F), both at native and adjusted pH, for 6 h. Step 2) NIH/3T3 were exposed to NaF or TiF4 varnishes with 0.95, 1.95 or 2.45% F (native pH), for 6, 12 or 24 h. We applied MTT (1st and 2nd steps) and Hoescht/PI stain (2nd step) assays. Step 3) NIH/3T3 were exposed to NaF or TiF4 varnish (2.45% F), at native pH, for 6 or 12 h. The cell stiffness was measured by atomic force microscopy (AFM). Results Step 1) All cells exposed to NaF or TiF4 mediums died, regardless of the F concentration and pH. Step 2) Both varnishes, at 1.90 and 2.45% F, reduced cell viability by similar extents (33–86% at 6 h, 35–93% at 12 h, and 87–98% at 24 h) compared with control, regardless of the type of fluoride. Varnishes with 0.95% F did not differ from control. Step 3) TiF4 and NaF reduced cell stiffness to a similar extent, but only TiF4 differed from control at 6 h. Conclusions Based on the results of the 3 experimental steps, we conclude that TiF4 and NaF have similar cytotoxicity. The cytotoxicity was dependent on F concentration and exposure time. This result gives support for testing the effect of TiF4 varnish in vivo.

Burn injury induces histopathological changes and cell proliferation in liver of rats

AIM To investigate effects of severe burn injury (BI) in rat liver through the histopathological and inflammatory markers analysis. METHODS Forty-two male Wistar rats were distributed into two groups, control (C) and subjected to scald BI (SBI). The animals were euthanized one, four and 14 d post sham or 45% of the total body surface BI. Liver fragments were submitted to histopathological, morphoquantitative (hepatocyte area and cell density), ciclooxigenase-2 (COX-2) immunoexpression, and gene expression [real-time polymerase chain reaction for tumor necrosis factor (TNF)-α, inducible nitric oxide synthase (iNOS) and caspase-3] methods. RESULTS Histopathological findings showed inflammatory process in all periods investigated and hepatocyte degeneration added to increased amount of connective tissue 14 d post injury. Hepatocyte area, the density of binucleated hepatocytes and density of sinusoidal cells of SBI groups were increased when compared with control. COX-2 immunoexpression was stronger in SBI groups. No differences were found in TNF-α, iNOS and caspase-3 gene expression. CONCLUSION BI induces histopathological changes, upregulation of COX-2 immunoexpression, and cell proliferation in liver of rats.

Burn Injury Induces Skeletal Muscle Degeneration, Inflammatory Host Response, and Oxidative Stress in Wistar Rats

Burn injuries (BIs) result in both local and systemic responses distant from the site of thermal injury, such as skeletal muscle. The purpose of this study was to investigate the expression of cyclooxygenase-2 (COX-2) and hydroxy-2′-deoxyguanosine (8-OHdG) as a result of inflammation and reactive oxygen species production, respectively. A total of 16 male rats were distributed into two groups: control (C) and submitted to BI. The medial part of gastrocnemius muscle formed the specimens, which were stained with hematoxylin and eosin and were evaluated. COX-2 and 8-OHdG expressions were assessed by immunohistochemistry, and cell profile area and density of muscle fibers (number of fibers per square millimeter) were evaluated by morphometric methods. The results revealed inflammatory infiltrate associated with COX-2 immunoexpression in BI-gastrocnemius muscle. Furthermore, a substantial decrease in the muscle cell profile area of BI group was noticed when compared with the control group, whereas the density of muscle fibers was higher in the BI group. 8-OHdG expression in numerous skeletal muscle nuclei was detected in the BI group. In conclusion, the BI group is able to induce skeletal muscle degeneration as a result of systemic host response closely related to reactive oxygen species production and inflammatory process.