Modulation of the Pharmacological Activities of Secretory Phospholipase A2 from Crotalus durissus cascavella Induced by Naringin

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Electrooxidation and determination of dopamine using a Nafion (R)-cobalt hexacyanoferrate film modified electrode

The electrocatalysis of dopamine has been studied using a cobalt hexacyanoferrate film (CoHCFe)-modified glassy carbon electrode. Using a rotating disk CoHCFe-modified electrode, the reaction rate constant for dopamine was found to be 3.5 x 105 cm(3) mol(-1) s(-1) at a concentration of 5.0 x 10(-5) mol L-1. When a Nafion (R) film is applied to the CoHCFe-modified electrode surface a high selectivity for the determination of dopamine over ascorbic acid was obtained. The analytical curve for dopamine presented linear dependence over the concentration range from 1.2 x 10(-5) to 5.0 x 10(-4) mol L-1 with a slope of 23.5 mA mol(-1) L and a linear correlation coefficient of 0.999. The detection limit of this method was 8.9 x 10(-6) mol L-1 and the relative standard deviation for five measurements of 2.5 x 10(-4) mol L-1 dopamine was 0.58%.

Guanidine Affects Differentially the Twitch Response of Diaphragm, Extensor Digitorum Longus and Soleus Nerve-Muscle Preparations of Mice

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Communication and synchronized molting in a colonial araneid spider, Eriophora bistriata

The colonial orb-weaving spider, Eriophora bistriata, coordinates molting cycles through communication. Colonies with differing molting cycles synchronize when combined. Intercycle intervals depend upon food availability. The possible coordination of this synchrony by chemical communication among spiders is discussed. © 1988 Birkhäuser Verlag Basel.

On a dual role for clonidine stimulation of the ventromedial nucleus of the hypothalamus in sodium and potassium renal excretions of rats

The effects of clonidine on sodium and potassium excretions were examined after previous administration of prazosin (an α 1-adrenergic receptor antagonist) and yohimbine (an α 2-adrenergic receptor antagonist) into the ventromedial nucleus of the hypothalamus of conscious rats. Clonidine injected into the ventromedial nucleus of the hypothalamus induced inhibitory and facilitatory effects on the urinary sodium and potassium excretions. The results suggest that facilitatory effects of clonidine on natriuresis and kaliuresis are mediated through activation of α 1-adrenoceptors and that inhibitory effects require α(2A)-adrenoceptors.

Sudden bilateral deafness from hyperleukocytosis in chronic myeloid leukemia

Sudden-onset bilateral deafness as a clinical manifestation of hyperleukocytosis in chronic myeloid leukemia (CML) is a rare occurrence. We found only 27 clinical descriptions in 16 published papers. In this work, the authors present a review on deafness in CML and describe a new case with prominent hyperleukocytosis, where the neurological findings suggest slowing of the circulation through small blood vessels in the brainstem as the cause of deafness. The evolution was good after treatment. To our knowledge, this is the second case documented with electrical auditory brainstem-evoked potentials and the first with magnetic resonance imaging. Copyright (C) 2000 S. Karger AG, Basel.

Effect of a meal feeding schedule on hepatic glycogen synthesis and gluconeogenesis in rats

We investigated the effect of a meal feeding schedule (MFS) on food intake, hepatic glycogen synthesis, hepatic capacity to produce glucose and glycemia in rats. The MFS comprised free access to food for a 2-hour period daily at a fixed mealtime (8.00-10.00 a.m.) for 13 days. The control group was composed of rats with free access to food from day 1 to 12, which were then starved for 22 h, refed with a single meal at 8.00-10.00 a.m. and starved again for another 22 h. All experiments were performed at the meal time (i.e. 8.00 a.m.). The MFS group exhibited increased food intake and higher glycogen synthase activity. Since gluconeogenesis from L-glutamine or L-alanine was not affected by MFS, we conclude that the increased food intake and higher glycogen synthase activity contributed to the better glucose maintenance showed by MFS rats at the fixed meal time. Copyright © 2001 National Science Council, ROC and S. Karger AG, Basel.

On the existence and stability of periodic orbits in non ideal problems: General results

In this work, motivated by non-ideal mechanical systems, we investigate the following O.D.E. ẋ = f (x) + εg (x, t) + ε2g (x, t, ε), where x ∈ Ω ⊂ ℝn, g, g are T periodic functions of t and there is a 0 ∈ Ω such that f (a 0) = 0 and f′ (a0) is a nilpotent matrix. When n = 3 and f (x) = (0, q (x 3) , 0) we get results on existence and stability of periodic orbits. We apply these results in a non ideal mechanical system: the Centrifugal Vibrator. We make a stability analysis of this dynamical system and get a characterization of the Sommerfeld Effect as a bifurcation of periodic orbits. © 2007 Birkhäuser Verlag, Basel.

Treatment of experimental periodontal disease by a selective inhibitor of cyclooxygenase-2 with scaling and root planing (SRP)

Lumiracoxib is a selective inhibitor of cyclooxygenase-2 (COX-2) approved for the relief of symptoms of chronic inflammatory conditions. The aim of this study was to evaluate the effects of this specific inhibitor of COX-2 as adjunctive treatment on induced periodontitis in rats. Periodontal disease was induced at the first mandibular molar of 60 rats. After 7 days, the ligature was removed and all animals were submitted to scaling and root planing (SRP) along with local irrigation with saline solution and were divided into 2 groups: SRP (n = 30)-received subcutaneous injections of 1 mg/kg of body weight/day of saline solution for 3 days and; SRP + L (n = 30)-received subcutaneous injections of 1 mg/kg of body weight/day of Lumiracoxib for 3 days. Ten animals in each group were killed at 7, 15, and 30 days. The histological description was performed and the histometric values were statistically analyzed. In Group SRP + L, the histometric analysis (0.58 ± 0.08, 0.64 ± 0.06, and 0.56 ± 0.10 mm 2) showed less bone loss (p < 0.05) than Group SRP (1.52 ± 0.08, 1.55 ± 0.09, and 1.49 ± 0.24 mm 2) at 7, 15, and 30 days, respectively. Within the limits of this study it can be concluded that subcutaneous application of specific inhibitor of COX-2 was a beneficial adjunctive treatment for periodontal diseases induced in rats. © 2010 Springer Basel AG.

Historical and recent biological markers of exposure to fluoride

Recent and historical biomarkers assess chronic or subchronic exposure to fluoride. The most studied recent biomarkers are nails and hair. Both can be non-invasively obtained, although collection of nails is more accepted by the subjects. External contamination may be a problem for both biomarkers and still needs to be better evaluated. Nails have been more extensively studied. Although the available knowledge does not allow their use as predictors of dental fluorosis by individual subjects, since reference values of fluoride have not yet been established, they have a strong potential for use in epidemiological surveys. Toenails should be preferred instead of fingernails, and variables that are known to affect nail fluoride concentrations - such as age, gender and geographical area - should be considered. The main historical biomarkers that could indicate total fluoride body burden are bone and dentin. Of these, bone is more studied, but its fluoride concentrations vary according to the type of bone and subjects' age and gender. They are also influenced by genetic background, renal function and remodeling rate, variables that complicate the establishment of a normal range of fluoride levels in bone that could indicate 'desirable' exposure to fluoride. The main issue when attempting to use bone as biomarker of fluoride exposure is the difficulty and invasiveness of sample collection. In this aspect, collection of dentin, especially from 3rd molars that are commonly extracted, is advantageous. However, mean values also span a wide range and reference concentrations have not been published yet. © 2011 S. Karger AG, Basel.

Mechanisms of action of fluoride for caries control

Fluoride was introduced into dentistry over 70 years ago, and it is now recognized as the main factor responsible for the dramatic decline in caries prevalence that has been observed worldwide. However, excessive fluoride intake during the period of tooth development can cause dental fluorosis. In order that the maximum benefits of fluoride for caries control can be achieved with the minimum risk of side effects, it is necessary to have a profound understanding of the mechanisms by which fluoride promotes caries control. In the 1980s, it was established that fluoride controls caries mainly through its topical effect. Fluoride present in low, sustained concentrations (sub-ppm range) in the oral fluids during an acidic challenge is able to absorb to the surface of the apatite crystals, inhibiting demineralization. When the pH is re-established, traces of fluoride in solution will make it highly supersaturated with respect to fluorhydroxyapatite, which will speed up the process of remineralization. The mineral formed under the nucleating action of the partially dissolved minerals will then preferentially include fluoride and exclude carbonate, rendering the enamel more resistant to future acidic challenges. Topical fluoride can also provide antimicrobial action. Fluoride concentrations as found in dental plaque have biological activity on critical virulence factors of S. mutans in vitro, such as acid production and glucan synthesis, but the in vivo implications of this are still not clear. Evidence also supports fluoride's systemic mechanism of caries inhibition in pit and fissure surfaces of permanent first molars when it is incorporated into these teeth pre-eruptively. © 2011 S. Karger AG, Basel.

Topical use of fluorides for caries control

Since the early findings on the protective effects of fluoride present in drinking water upon caries incidence and prevalence, intensive research has been conducted in order to determine the benefits, safety, as well as the cost-effectiveness of other modalities of fluoride delivery. The present chapter reviews the various forms of topical fluoride use - professionally and self-applied - with special emphasis on clinical efficacy and possible side effects. The most widely used forms of fluoride delivery have been subject of several systematic reviews, providing strong evidence supporting the use of dentifrices, gels, varnishes and mouth rinses for the control of caries progression. Dentifrices with fluoride concentrations of 1,000 ppm and above have been shown to be clinically effective in caries prevention when compared to a placebo treatment, but the evidence regarding formulations with 450-550 ppm is still subject of debate. Therefore, the recommendation for low-fluoride dentifrice use must take into account both risks and benefits. The evidence for the combined use of two modalities of fluoride application in comparison to a single modality is still inconsistent, implying that more studies with adequate methodology are needed to determine the real benefits of each method. Considering the currently available evidence and risk-benefit aspects, it seems justifiable to recommend the use of fluoridated dentifrices to individuals of all ages, and additional fluoride therapy should also be targeted towards individuals at high caries risk. © 2011 S. Karger AG, Basel.

Anti-nociceptive effects of Carpolobia lutea G. Don (Polygalaceae) leaf fractions in animal models

Leaves from Carpolobia lutea (Polygalaceae) were screened to establish the antiulcer ethnomedicinal claim and to quantitatively isolate, elucidate the active compounds by semi-preparative HPLC. The anti-nociceptive effects of Carpolobia lutea (CL) G. Don (Polygalaceae) organic leaf extracts were tested in experimental models in mice. The anti-nociceptive mechanism was determined using tail-flick test, acetic acid-induced abdominal constrictions, formalin-induced hind paw licking and the hot plate test. The fractions (ethanol, ethyl acetate, chloroform, n-hexane) and crude ethyl acetate extract of CL (770 mg/kg, i.p.) produced significant inhibitions of both phases of the formalin-induced pain in mice, a reduction in acetic acid-induced writhing as well as and an elevation of the pain threshold in the hot plate test in mice. The inhibitions were greater to those produced by indomethacin (5 mg/kg, i.p.). Ethyl acetate fraction revealed cinnamic and coumaric acids derivatives, which are described for the first time in literature. These cinnamalglucosides polyphenols characterised from CL may in part account for the pharmacological activities. These findings confirm its ethnomedical use in anti-inflammatory pain and in pains from gastric ulcer-associated symptoms. © 2011 Springer Basel AG.

Development and validation of a microbiological agar assay for determination of orbifloxacin in pharmaceutical preparations

Orbifloxacin is a fluoroquinolone with broad-spectrum antimicrobial activity, and belongs to the third generation of quinolones. Regarding the quality control of medicines, a validated microbiological assay for determination of orbifloxacin in pharmaceutical formulations has not as yet been reported. For this purpose, this paper reports the development and validation of a simple, sensitive, accurate and reproducible agar diffusion method to quantify orbifloxacin in tablet formulations. The assay is based on the inhibitory effect of orbifloxacin upon the strain of Staphylococcus aureus ATCC 25923 used as test microorganism. The results were treated statistically by analysis of variance and were found to be linear (r = 0.9992) in the selected range of 16.0-64.0 μg/mL, precise with relative standard deviation (RSD) of repeatability intraday = 2.88%, intermediate precision RSD = 3.33%, and accurate (100.31%). The results demonstrated the validity of the proposed bioassay, which allows reliable orbifloxacin quantitation in pharmaceutical samples and therefore can be used as a useful alternative methodology for the routine quality control of this medicine. © 2011 by the authors; licensee MDPI, Basel, Switzerland.

Effects of the ethyl acetate fraction of Alchornea triplinervia on healing gastric ulcer in rats

Alchornea triplinervia (Spreng.) Muell. Arg (Euphorbiaceae) is a medicinal plant commonly used by people living in the Cerrado region of Brazil to treat gastrointestinal ulcers. We previously described the gastroprotective action of methanolic extract (ME) of Alchornea triplinervia and the ethyl acetate fraction (EAF) in increasing of prostaglandin E 2 (PGE 2) gastric levels in the mucosa. In this work we evaluated the effect of EAF in promoting the healing process in rats with acetic acid-induced gastric ulcers. In addition, toxicity was investigated during treatment with EAF. After 14 days of treatment with EAF, the potent stimulator of gastric cell proliferation contributed to the acceleration of gastric ulcer healing. Upon immunohistochemical analysis, we observed a pronounced expression of COX-2, mainly in the submucosal layer. The 14-day EAF treatment also significantly increased the number of neutrophils in the gastric mucosa regeneration area. The EAF induced angiogenesis on gastric mucosa, observed as an increase of the number of blood vessels supplying the stomach in rats treated with EAF. Oral administration for 14 days of the ethyl acetate fraction from Alchornea triplinervia accelerated the healing of gastric ulcers in rats by promoting epithelial cell proliferation, increasing the number of neutrophils and stimulation of mucus production. This fraction, which contained mainly phenolic compounds, contributed to gastric mucosa healing. © 2011 by the authors; licensee MDPI, Basel, Switzerland.