Leptomeningeal Interfoliar Enhancement on Vessel Wall MR Imaging as a Unique Radiologic Finding of Susac Syndrome.

Susac syndrome is a rare disorder affecting the brain, retina, and inner ear, probably triggered by an immune-mediated endotheliopathy. Diagnosis is based on clinical presentation and ancillary test findings (brain MR imaging, fluorescein angiography, and audiometry). Recently, vessel wall MR imaging has shown increased sensitivity in the detection of subtle signs of parenchymal, leptomeningeal, and vestibulocochlear enhancement. In this report, we describe a unique finding identified using this technique in a series of 6 patients with Susac syndrome and discuss its potential value for diagnostic work-up and follow-up.

Photoinactivation of Aedes aegypti larvae using riboflavin as photosensitizer.

More than half of the global population lives in areas where the Aedes aegypti mosquito is present. Efforts have been made to deal with the population of this mosquito in the larval and adult stages to prevent outbreaks of diseases (Dengue, Zika, Chikungunya, and Yellow Fever). In this scenario, photodynamic inactivation may be an effective alternative method to control this vector population. To evaluate the efficacy of the riboflavin - B2 vitamin - as photosensitizer (PS) in the photodynamic inactivation of Ae. aegypti larvae, different concentrations (0; 0.005; 0.010; 0.025; 0.050; 0.075 and 0.100 mg mL-1) were evaluated under white light from RGB LEDs at a light dose of 495.2  J cm-2. The results reveal that riboflavin can be successfully applied as a PS agent to photoinactivate Ae. aegypti larvae, showing its potential to deal with the larvae population.

Brain and spinal cord lesion criteria distinguishes AQP4-positive neuromyelitis optica and MOG-positive disease from multiple sclerosis.

OBJECTIVE: Test the ability of a brain and spinal cord MRI criteria to differentiate neuromyelitis optica spectrum disorders and MOG-disease from MS. MRI criteria was further tested in patients with CIS and pediatric MS. BACKGROUND: MOG-disease and neuromyelitis optica spectrum disorders can present clinical and radiological features strikingly similar to those of MS. Previously, diagnostic criteria based on brain MRI have been proposed to distinguish between these demyelinating diseases (Matthews-Jurynczik criteria), but spinal cord imaging and its relevance in CIS have not been evaluated. Simple brain and spinal cord MRI criteria may help separate these three inflammatory CNS diseases both in adults and children, aiding in early diagnostic decision-making, such as need for antibody testing. DESIGN/METHODS: We included 150 participants (23 with aquaporin-4-positive neuromyelitis optica spectrum disorder, 14 with MOG-disease, 20 with aquaporin-4-negative neuromyelitis optica spectrum disorder, 48 with adult-onset relapsing remitting MS, 24 with pediatric-onset MS and 21 with clinically isolated syndrome). Brain and spinal cord MRI scans were anonymised and scored by 2 separate raters, based on two sets of criteria: one previously described by Matthews and colleagues (including presence of at least one lesion adjacent to the body of lateral ventricle and in the inferior temporal lobe, or presence of subcortical U-fiber lesion or a Dawson's finger-type lesion), and an extended version including spinal cord features (non-longitudinally extensive cervical lesion). RESULTS: Extended MRI brain and spinal cord lesion criteria were able to separate adult-onset relapsing remitting MS with 100% sensitivity and 87% specificity from aquaporin-4-positive neuromyelitis optica spectrum disorder; and with 100% sensitivity and 79% specificity from MOG-disease. Additionally, brain and spinal cord criteria showed 100% sensitivity and specificity in patients presenting optic neuritis. Brain and spinal cord criteria were less sensitive in patients with CIS and in pediatric MS patients. CONCLUSIONS: Our data suggest radiological criteria can be useful to separate MS from MOG- and aquaporin-4-positive neuromyelitis optica spectrum disorders, in particular in patients with optic neuritis. Further work is needed to support their use in CIS.

Effect of pre-emptive analgesia on clinical parameters and tissue levels of TNF-α and IL-1ß in third molar surgery: a triple-blind, randomized, placebo-controlled study.

This study aimed to evaluate whether pre-emptive analgesia modifies the tissue expression of tumour necrosis factor alpha (TNF-α) and interleukin 1 beta (IL-1ß), and whether there is an association with postoperative surgical outcomes. A triple-blind, randomized, placebo-controlled study of patients undergoing mandibular third molar removal was performed. Volunteers were allocated randomly to receive etoricoxib 120 mg, ibuprofen 400 mg, or placebo 1h before surgery. Twenty-four surgical sites per group were required (95% confidence level and 80% statistical power). Pain scores differed significantly between groups (P<0.001). Etoricoxib and ibuprofen reduced pain scores compared to placebo (P<0.05). Pain scores peaked at 4h postoperative in the experimental groups, but at 2h postoperative in the placebo group (P<0.05). A significant reduction in TNF-α concentration from time 0' to time 30' was seen for ibuprofen (P=0.001) and etoricoxib (P=0.016). The ibuprofen group showed a significant reduction in IL-1ß levels from time 0' to time 30' (P=0.038). In conclusion, TNF-α and IL-1ß levels and the inflammatory events in third molar surgery were inversely associated with the degree of cyclooxygenase 2 selectivity of the non-steroidal anti-inflammatory drugs used pre-emptively. Patients given pre-emptive analgesia showed significant reductions in the clinical parameters pain, trismus, and oedema when compared to the placebo group.

O role-playing entre surdos: discurso e cognição / The role-playing between deaf: discourse and cognition

O role-playing é um tipo de atividade que tem inúmeros propósitos, dentre os quais a prática deestratégias militares e a formação de competências nas mais diversas áreas, como medicina, direito,administração, etc. Este relato de pesquisa tem por objetivo analisar a relação entre discurso e cogniçãode surdos quando estes realizavam esse tipo de atividade. O corpus foi obtido a partir da filmagem deuma atividade realizada por surdos. A turma era composta por seis estudantes que estavam realizando umjogo de role-playing. Considerando o fenômeno linguagem em sua amplitude, pôde-se verificar que ocampo metafórico da situação lúdica fornece mais que uma estilística do jogar. O que se percebeu foi queno próprio jogo subjazem metáforas, ordenadas por regras(AU)

Influence of white matter MRI hyper-intensities on acute l-dopa response in patients with Parkinson's disease.

OBJECTIVE: To determine whether brain white matter hyperintensities (WMH) influence l-dopa response in Parkinson's disease (PD) patients. METHODS: We prospectively evaluated 60 PD patients with an acute l-dopa challenge test, and assessed motor performance with the Movement Disorders Society revised Unified Parkinson's Disease Rating Scale (MDS-UPDRS) during "ON" and "OFF" medication states. Magnetic resonance images were examined using a visual semi-quantitative rating scale for quantification and distribution analysis of WMH. l-dopa challenge test response was correlated to extent and location of WMH, to determine a potential association between them. RESULTS: Subjects with greater deep WMH burden, showed less response to l-dopa on axial motor symptoms (R = -0.35; p < 0.027), when tested with Part III of the MDS-UPDRS before and after acute levodopa challenge. CONCLUSIONS: Results suggest WMH may affect response to l-dopa on axial function of PD patients, which could be due to either non-dopaminergic (cortico-basal ganglia) motor pathway disruption, or postsynaptic nigrostriatal pathway involvement.

Tephrosia toxicaria†Pers. reduces temporomandibular joint inflammatory hypernociception: the involvement of the HO-1 pathway.

BACKGROUND: We investigated both the efficacy and the sub-chronic toxicity of Tephrosia toxicaria Pers. in the zymosan-induced temporomandibular joint (TMJ) inflammatory hypernociception in rats evaluating the possible role of heme oxygenase-1 (HO-1). METHODS: Rats were pretreated with T. toxicaria (0.2, 2.0 or 20 mg/kg) 60 min before the intra-articular injection of zymosan (2 mg, 40 µL) in the left TMJ. In another series of experiments, rats were treated with ZnPP-IX (3 mg/kg), a specific HO-1 inhibitor, before T. toxicaria (20 mg/kg). Von Frey test was used to evaluate inflammatory hypernociception (g) 4 h after zymosan injection. Six hours after zymosan injection, the synovial lavage was collected for total cell count and myeloperoxidase (MPO) activity, and joint tissue for histopathological analysis and immunohistochemistry for HO-1. To evaluate the sub-chronic toxicity, mice received T. toxicaria (20 mg/kg) or saline once a day for 14 days to analyse body mass, organ weight and biochemical parameters. RESULTS: T. toxicaria partially reversed the zymosan-induced head withdrawal threshold, the number of cells and the MPO activity. T. toxicaria reduced the inflammatory cell influx in the synovial membrane. TMJ immunohistochemical analyses treated with T. toxicaria showed increased HO-1 expression. These effects of T. toxicaria were not observed in the presence of ZnPP-IX. T. toxicaria treatment for 14 days did not show significant signs of toxicity when administrated to mice. CONCLUSIONS: T. toxicaria did not produce any signs of toxicity and effectively decreased zymosan-induced TMJ inflammatory hypernociception dependent, at least in part, upon the HO-1 pathway integrity.

Neurografía de alta resolución del nervio peroneo en resonancia magnética 3T / High resolution 3T magnetic resonance neurography of the peroneal nerve

La neuropatía del nervio peroneo es la mononeuropatía más común de los miembros inferiores. Entre las causas se incluyen el traumatismo, los tumores del nervio y de la vaina, el atrapamiento, y otras como el perineuroma, la fibromatosis, el linfoma y el ganglión intraneural y extraneural. El diagnóstico se basa en las manifestaciones clínicas y los estudios electrofisiológicos. Actualmente, sin embargo, el complemento diagnóstico con neurografía por resonancia magnética (RM) permite aproximarse al lugar y la causa de esta neuropatía. El objetivo de este trabajo es describir con la RM la anatomía del nervio peroneo, sus relaciones y los músculos que inerva; mencionar las manifestaciones clínicas y electrofisiológicas de sus lesiones; describir los parámetros técnicos que se emplean en nuestra institución; y mostrar la apariencia en RM de las diversas enfermedades que afectan al nervio peroneo (AU)

Peroneal neuropathy is the most common mononeuropathy of the lower limbs. The causes of peroneal neuropathy include trauma, tumors of the nerve and nerve sheath, entrapment, and others like perineurioma, fibromatosis, lymphoma, and intraneural and externeural ganglia. The diagnosis is based on clinical manifestations and electrophysiological studies. Nowadays, however, magnetic resonance (MR) neurography is a complementary diagnostic technique that can help determine the location and cause of peroneal neuropathy. In this article, we describe the MR anatomy of the peroneal nerve, its relations, and the muscles it innervates. We also discuss the clinical and electrophysiological manifestations of peroneal neuropathy, describe the technical parameters used at our institution, and illustrate the MR appearance of various diseases that involve the peroneal nerve (AU)

[High resolution 3T magnetic resonance neurography of the peroneal nerve]. / Neurografía de alta resolución del nervio peroneo en resonancia magnética 3T.

Peroneal neuropathy is the most common mononeuropathy of the lower limbs. The causes of peroneal neuropathy include trauma, tumors of the nerve and nerve sheath, entrapment, and others like perineurioma, fibromatosis, lymphoma, and intraneural and externeural ganglia. The diagnosis is based on clinical manifestations and electrophysiological studies. Nowadays, however, magnetic resonance (MR) neurography is a complementary diagnostic technique that can help determine the location and cause of peroneal neuropathy. In this article, we describe the MR anatomy of the peroneal nerve, its relations, and the muscles it innervates. We also discuss the clinical and electrophysiological manifestations of peroneal neuropathy, describe the technical parameters used at our institution, and illustrate the MR appearance of various diseases that involve the peroneal nerve.

Histology of palate and soft palate tonsil of collared peccary (Tayassu tajacu).

Peccaries are characterized by a prominent skin gland, known as scent gland, which is located in the middle of the rump. These animals are able to survive in a great variety of habitats, from humid tropical forests to semi-arid areas. They are omnivorous animals, and their diet includes fibrous material, vegetables, fruits, small vertebrates and insects. Collared peccary hard palate and soft palate tonsils were studied, macroscopic morphometric data were collected and tissue samples were paraffin-embedded. Sections were stained with HE, Gomori's trichrome and von Kossa; the first two were used to study general organization and the latter to detect calcium deposits. The hard palate showed one incisive papilla followed by several rugae united by a distinct raphe. The hard palate is lined by a keratinised squamous epithelium resting on a dense connective, whereas in the soft palate, the epithelium is parakeratinised and showed lymphocyte infiltration. The palate showed several pacinian corpuscles in the propria-submucosa. Two ovoid-shaped tonsils were found in the soft palate, and several crypts were observed on its surface. The epithelium was highly infiltrated by lymphocytes, and within the crypts, tonsilloliths were frequently observed. The study showed that the general organization of collared peccary palate is similar to other species, but in its oropharynx, only the soft palate tonsil was present and the pacinian corpuscles formed small aggregates.

Protective effect of Chresta martii extract against indomethacin-induced gastric lesions in mice.

Chresta martii (Asteraceae) is a plant found in the Xingó region (semi-arid area) in Northeastearn Brazil, and is recognized by the local population as a traditional herb used to treat gastric diseases. This is the first report of the chemical composition, acute toxicity, and gastroprotective effect in mice of the hydroalcoholic extract (HAE) from the aerial parts (leaves and flowers) of Chresta martii. Animals received HAE doses from 10 to 2000 mg/kg, i.p. or 50 to 3000 mg/kg, p.o.) and were observed over 48 h for toxicity signs and mortality; sub-chronic toxicity was evaluated through 14 days treatment with once-daily HAE doses (400 mg/kg, p.o.). The gastroprotective effect of HAE was demonstrated on the indomethacin-induced gastric ulcer model after the administration of extracts. Data comparison of ulcer index averages between saline and HAE (100 or 400 mg/kg, p.o.) groups showed significant (P < 0.01) inhibition (71.73 and 76.72 %, respectively) of indomethacin-induced gastric lesions. Histological analyses showed significant (P < 0.05) inhibition of leukocyte migration in HAE-treated groups. A fingerprint of the HAE obtained by HPLC/UV/MS analysis showed major peaks characteristic of sesquiterpene lactones. Compound 1 was isolated and elucidated as a new natural product. Its capacity to prevent leukocyte chemotaxis was demonstrated in vitro, corroborating the pharmacological effects observed for C. martii HAE.

Is arterial stiffness in HIV-infected individuals associated with HIV-related factors?

We investigated the association between pulse wave velocity (PWV) and HIV infection, antiretroviral treatment-related characteristics, viral load, immune status, and metabolic changes in a cross-sectional study nested in a cohort of HIV/AIDS patients who have been followed for metabolic and cardiovascular changes since 2007. The study included patients recruited from the cohort (N = 261) and a comparison group (N = 82) of uninfected individuals, all enrolled from April to November 2009. Aortic stiffness was estimated using the carotid-femoral PWV (Complior-Artech, Paris, France). The groups were similar with respect to age, metabolic syndrome, diabetes mellitus, Framingham score, and use of antihypertensive and hypolipidemic medications. Hypertension was more frequent among the controls. Individuals with HIV had higher triglyceride, glucose and HDL cholesterol levels. Among individuals with HIV/AIDS, those with a nadir CD4+ T-cell count <200 cells/mm³ had a higher PWV (P = 0.01). There was no statistically significant difference when subjects were stratified by gender. Heart rate, age, male gender, and blood pressure were independently correlated with PWV. Nadir CD4+ T-cell count did not remain in the final model. There was no significance difference in PWV between HIV-infected individuals and uninfected controls. PWV was correlated with age, gender, and blood pressure across the entire population and among those infected with HIV. We recommend cohort studies to further explore the association between inflammation related to HIV infection and/or immune reconstitution and antiretroviral use and PWV.

Is arterial stiffness in HIV-infected individuals associated with HIV-related factors?

We investigated the association between pulse wave velocity (PWV) and HIV infection, antiretroviral treatment-related characteristics, viral load, immune status, and metabolic changes in a cross-sectional study nested in a cohort of HIV/AIDS patients who have been followed for metabolic and cardiovascular changes since 2007. The study included patients recruited from the cohort (N = 261) and a comparison group (N = 82) of uninfected individuals, all enrolled from April to November 2009. Aortic stiffness was estimated using the carotid-femoral PWV (Complior-Artech, Paris, France). The groups were similar with respect to age, metabolic syndrome, diabetes mellitus, Framingham score, and use of antihypertensive and hypolipidemic medications. Hypertension was more frequent among the controls. Individuals with HIV had higher triglyceride, glucose and HDL cholesterol levels. Among individuals with HIV/AIDS, those with a nadir CD4+ T-cell count <200 cells/mm³ had a higher PWV (P = 0.01). There was no statistically significant difference when subjects were stratified by gender. Heart rate, age, male gender, and blood pressure were independently correlated with PWV. Nadir CD4+ T-cell count did not remain in the final model. There was no significance difference in PWV between HIV-infected individuals and uninfected controls. PWV was correlated with age, gender, and blood pressure across the entire population and among those infected with HIV. We recommend cohort studies to further explore the association between inflammation related to HIV infection and/or immune reconstitution and antiretroviral use and PWV.

Channelling optics for high quality imaging of sensory hair.

A long distance microscope (LDM) is extended by a lens and aperture array. This newly formed channelling LDM is superior in high quality, high-speed imaging of large field of views (FOV). It allows imaging the same FOV like a conventional LDM, but at improved magnification. The optical design is evaluated by calculations with the ray tracing code ZEMAX. High-speed imaging of a 2 × 2 mm(2) FOV is realized at 3.000 frames per second and 1 µm per pixel image resolution. In combination with flow sensitive hair the optics forms a wall shear stress sensor. The optics images the direct vicinity of twenty-one flow sensitive hair distributed in a quadratic array. The hair consists of identical micro-pillars that are 20 µm in diameter, 390 µm in length and made from polydimethylsiloxane (PDMS). Sensor validation is conducted in the transition region of a wall jet in air. The wall shear stress is calculated from optically measured micro-pillar tip deflections. 2D wall shear stress distributions are obtained with currently highest spatiotemporal resolution. The footprint of coherent vortical structures far away from the wall is recovered in the Fourier spectrum of wall shear stress fluctuations. High energetic patterns of 2D wall shear stress distributions are identified by proper orthogonal decomposition (POD).

Metabolic syndrome prevalence is increased in rheumatoid arthritis patients and is associated with disease activity.

OBJECTIVES: To evaluate the prevalence of metabolic syndrome (MetS) in patients with rheumatoid arthritis (RA) vs. controls, and to verify possible associations of MetS with specific disease-related factors. METHODS: The subjects were 283 RA patients and 226 healthy controls, frequency matched by age and sex. MetS was defined according to National Cholesterol Education Program (NCEP) criteria. Disease activity was evaluated with the Disease Activity Score using 28 joints (DAS28). A standardized clinical evaluation was performed and cardiovascular risk factors were assessed. RESULTS: The criteria for MetS were met by 39.2% RA patients vs. 19.5% in the control group (p < 0.001). Increased waist circumference, elevated blood pressure (BP), and fasting glucose were more frequent in RA patients than controls (p < 0.001 for all associations). By multiple logistic regression analysis (adjusted for age, sex, and years at school), the risk of having MetS was significantly higher for RA patients than for controls [odds ratio (OR) 1.87, 95% confidence interval (CI) 1.17-3.00, p = 0.009]. The DAS28 was significantly higher in RA patients with MetS than in those without MetS (3.59 ± 1.27 vs. 3.14 ± 1.53; p = 0.01). Disease duration, the presence of rheumatoid factor, and extra-articular manifestations were similar for patients with and without MetS. CONCLUSIONS: MetS frequency was higher in RA patients than in controls. Among RA patients, MetS was associated with disease activity. The higher prevalence of cardiovascular risk factors in RA suggests that inflammatory processes play a notable role in the development of cardiovascular disease (CVD), and indicates that tight control of systemic inflammatory activity and CVD modifiable risk factors should be recommended.

Cranz-Schardin camera with a large working distance for the observation of small scale high-speed flows.

The Cranz-Schardin camera utilizes a Q-switched Nd:YAG laser and four single CCD cameras. Light pulse energy in the range of 25 mJ and pulse duration of about 5 ns is provided by the laser. The laser light is converted to incoherent light by Rhodamine-B fluorescence dye in a cuvette. The laser beam coherence is intentionally broken in order to avoid speckle. Four light fibers collect the fluorescence light and are used for illumination. Different light fiber lengths enable a delay of illumination between consecutive images. The chosen interframe time is 25 ns, corresponding to 40 × 10(6) frames per second. Exemplarily, the camera is applied to observe the bow shock in front of a water jet, propagating in air at supersonic speed. The initial phase of the formation of a jet structure is recorded.

Visualizing flow partitioning in a model of the upper human lung airways.

The convective transport of fluid within the human upper airways is investigated in a transparent model of the tracheobronchial tree. Oscillatory flow through the branching network with six generations was studied at varying Reynolds numbers between 400 and 2600 and Womersley numbers from 5.5 to 12.3 in the trachea representing clinical conditions during high frequency oscillatory ventilation. The flow partitioning within the model was visualized using advection of neutrally buoyant tracer particles, which were illuminated by short light pulses and recorded by a high speed camera. Integration of the particle locations for a large number of cycles provides the probability distribution of particles passing certain branches within the bifurcating network, and thus, the dispersion of particles in the airways. The results show the different characteristics of flow partitioning at varying Womersley and Reynolds numbers.

Single-pill amlodipine/atorvastatin helps patients of diverse ethnicity attain recommended goals for blood pressure and lipids (the Gemini-AALA study).

The Gemini-AALA (Australia, Asia, Latin America, Africa/Middle East) study evaluated the efficacy and safety of single-pill amlodipine/atorvastatin (Caduet) for the treatment of patients of diverse ethnicity with concomitant hypertension and dyslipidaemia. This was a 14-week, open-label study including patients from 27 countries across the Middle East, Asia-Pacific, Africa and Latin America. Eight dosage strengths of single-pill amlodipine/atorvastatin (5/10, 10/10, 5/20, 10/20, 5/40, 10/40, 5/80 and 10/80 mg) were titrated to improve blood pressure and lipid control. Blood pressure and lipid goals were determined according to the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC 7) and National Cholesterol Education Program Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (NCEP ATP III) guidelines, respectively (blood pressure, <140/90 or <130/80 mm Hg; low-density lipoprotein cholesterol (LDL-C), <4.1 to <2.6 mmol l(-1) (<160 to <100 mgdl(-1))). Overall, 1649 patients received study medication. Most patients (91.4%) had >or=1 cardiovascular risk factor (as defined by NCEP ATP III guidelines) in addition to hypertension/dyslipidaemia, and 61.7% had coronary heart disease/risk equivalent. At baseline, mean blood pressure was 146.6/88.3 mm Hg and LDL-C was 3.4 mmol l(-1) (130.2 mgdl(-1)). At week 14, 55.2% of patients reached both blood pressure and lipid goals, 61.3% reached blood pressure goal and 87.1% reached lipid goal (34.0% were at lipid goal at baseline). Mean blood pressure reduction was 20.2/11.4 mm Hg. For patients who were lipid-lowering drug naive at baseline, mean reduction in LDL-C was 41.0%. Treatment-related adverse events led to the discontinuation of 3.6% of patients. Single-pill amlodipine/atorvastatin therapy was well tolerated and effective for the reduction of blood pressure and lipids to recommended goals in patients from diverse ethnic backgrounds.

Nitric oxide synthase inhibition prevents alveolar bone resorption in experimental periodontitis in rats.

BACKGROUND: Periodontitis is the most frequent cause of tooth loss in adults. Nitric oxide (NO) has been linked to bone resorption mechanisms during inflammation processes. The aim of this study was to investigate the effect of NOS (NO synthase) inhibitors in the alveolar bone loss in an experimental periodontitis disease (EPD) model. METHODS: Wistar rats were subjected to a ligature placement around the second upper left molars and were sacrificed at 11 days. Alveolar bone loss was evaluated by the sum of distances between the cusp tips and the alveolar bone along the axis of each molar root, subtracting from the contralateral side. Histopathological analysis was based on cell influx, alveolar bone, and cementum integrity. Leukogram was performed at 6 hours and 1, 7, and 11 days after the EPD induction. Groups were treated with the NOS inhibitors, aminoguanidine (AG) (2.5 to 10 mg/kg/d), or L-arginine methyl ester (L-NAME, 5 to 20 mg/kg/d) intraperitoneally (i.p.), 1 hour before the EPD induction and daily for 11 days. Controls received only saline (EPD group). As controls for L-NAME specificity, groups were co-treated with either L-arginine (150 to 600 mg/kg/d) or D-arginine (600 mg/kg/d) and L-NAME (20 mg/kg/d). Different groups were used for morphometric and histopathological analysis. RESULTS: Both L-NAME and AG significantly and dose-dependently inhibited the alveolar bone loss as compared to EPD group. L-NAME (20 mg/kg/d) reduced the alveolar bone loss by 50%, whereas AG (5 mg/kg/d) reduced it by 47% compared to EPD. This result was coupled to a significant reduction of cell influx to the periodontium, as well as to the preservation of alveolar bone and cementum, seen at histopathology, for both compounds. The co-administration of L-arginine, but not of D-arginine reversed L-NAME effects. CONCLUSION: These data provide evidence that NOS inhibitors prevent inflammatory bone resorption in experimental periodontitis.