Histological evaluation of chitosan-based biomaterials used for the correction of critical size defects in rat's calvaria

Chitosan, a biopolymer obtained from chitin, and its derivates, such as chitosan hydrochloride, has been reported as wound healing accelerators and as possible bone substitutes for tissue engineering, and therefore these Substances could be relevant in dentistry and periodontology. The purpose of this investigation was to make a histological evaluation of chitosan and chitosan hydrochloride biomaterials (gels) used in the correction of critical size bone defects made in rat's calvaria. Bone defects of 8 mm in diameter were surgically created in the calviria of 50 Holtzman (Rattus norvegicus) rats and filled with blood clot (control), low molecular weight chitosan, high molecular weight chitosan, low molecular weight chitosan hydrochloride, and high molecular weight chitosan hydrochloride, numbering 10 animals, divided into two experimental periods (15 and 60 days), for each biomaterial. The histological evaluation was made based on the morphology of the new-formed tissues in defect's region, and the results indicated that there was no statistical difference between the groups when the new bone formation in the entire defect's area were compared (p > 0.05) and, except in the control groups, assorted degrees of inflammation Could be Seen. In Conclusion, chitosan and chitosan hydrochloride biomaterials used in this study were not able to promote new bone formation in critical size defects made in rat's calvaria. (C) 2009 Wiley Periodicals, Inc. J Biomed Mater Res 93A: 107-114, 2016

Different Molecular Weight Chitosan-Based Membranes for Tissue Regeneration

Natural polymers, such as chitosan, obtained from chitin, are been widely studied for use in the tissue regeneration field. This study established a protocol to attain membranes made from this biopolymer, consisting of high or low molecular weight chitosan. The biocompatibility of these membranes was histologically evaluated, comparing them to collagen membrane surgically implanted in rat subcutaneous tissue. Fifteen Holtzmann rats were divided in three experimental groups: High and Low Molecular Weight Chitosan membranes (HMWC and LMWC) and Collagen membranes (C-control group); each of them with three experimental periods: 7, 15 and 30 days. As a result, after the seven days evaluation, the membranes were present and associated with a variable degree of inflammation, and after the 15 and 30 days evaluations, the membranes were absent in all groups. It is concluded that the chitosan-based membranes were successfully attained and presented comparable resorption times to collagen membranes.

5-HT2 and 5-HT3 receptors in the lateral parabrachial nucleus mediate opposite effects on sodium intake

The present study investigated the role of several 5-HT receptor subtypes in the lateral parabrachial nucleus (LPBN) in the control of sodium appetite (i.e. NaCl consumption). Male Holtzman rats had cannulas implanted bilaterally into the LPBN for the injection of 5-HT receptor agonists and antagonists in conjunction with either acute fluid depletion or 24-h sodium depletion. Following these treatments, access to 0.3 M NaCl was provided and the intakes of saline and water were measured for the next 2 h. Bilateral injections of the 5-HT2A receptor antagonist, ketanserin or the 5-HT2C receptor antagonist, mianserin into the LPBN increased 0.3 M NaCl intake without affecting water intake induced by acute fluid-depletion. Bilateral injections of the 5-HT2B receptor agonist, BW723C86 hydrochloride, had no effect on 0.3 M NaCl or water intake under these conditions. Treatment of the LPBN with the 5-HT2B/2C receptor agonist, 2-(2-methyl-4-clorophenoxy) propanoic acid (mCPP) caused dose-related reductions in 0.3 M NaCl intake after 24 h sodium depletion. The effects of mCPP were prevented by pretreating the LPBN with the 5-HT2B/2C receptor antagonist, SDZSER082. Activation of 5-HT3 receptors by the receptor agonist, 1-phenylbiguanicle (PBG) caused dose-related increases in 0.3 M NaCl intake. Pretreatment of the LPBN with the 5-HT3 receptor antagonist, 1-methyl-N-[8-methyl-8-azabicyclo (3.2.1)-oct-3-yl]-1H-indazole-3-carboxamide (LY-278,584) abolished the effects of PBG, but LY-278,584 had no effects on sodium or water intake when injected by itself. PBG injected into the LPBN did not alter intake of palatable 0.06 M sucrose in fluid replete rats. The results suggest that activation of the 5-HT2A and 5-HT2C receptor subtypes inhibits sodium ingestion. In contrast, activation of the 5-HT3 receptor subtype increases sodium ingestion. Therefore, multiple serotonergic receptor subtypes in the LPBN are implicated in the control of sodium intake, sometimes by mediating opposite effects of 5-HT. The results provide new information concerning the control of sodium intake by LPBN mechanisms. (C) 2007 IBRO. Published by Elsevier Ltd. All rights reserved.

Antimicrobial activity of disinfectant agents incorporated into type IV dental stone

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Functional effects of castration on alpha(1)-adrenoceptors in rat vas deferens

The effects of castration on alpha(1)-adrenoceptors in rat vas deferens were investigated by determining the actions of selective antagonists against the contractions induced by noradrenaline. The results obtained in vas deferens from control rats suggest participation of alpha(1A)-adrenoceptors as judged by the pA(2) values for prazosin (9.6), benoxathian (9.5), 2(2,6-dimethoxyphenoxyethyl) amino-methyl-1,4-benzodioxone hydrochloride) (WB 4101) (9.6), phentolamine (8.4), 8-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-8-azaspiro[4.5] decane-7,9-dionedihydrochloride (BMY 7378) (6.7) and by the insensitivity to chloroethylclonidine (100 mu M, 45 min). In vas deferens from castrated rats, WE 4101 and spiperone showed slopes lower than 1.0 in the Schild plots, suggesting participation of multiple receptors. In these organs, noradrenaline contractions were partially inhibited by chloroethylclonidine (100 mu M, 45 min), indicating participation of alpha(1B)-adrenoceptors. After chloroethylclonidine treatment, WE 4101 showed a slope not different from 1.0 in the Schild plot, resulting in a pA(2) of 9.4, which indicates an interaction with alpha(1A)-adrenoceptors. It is suggested that castration modifies the functional alpha(1)-adrenoceptors subtypes in rat vas deferens. (C) 1998 Elsevier B.V. B.V. All rights reserved.

Effects of castration and of testosterone replacement on alpha(1)-adrenoceptor subtypes in the rat vas deferens

The contractions of the rat vas deferens in response to noradrenaline are mediated through alpha(1A)-adrenoceptors. We observed participation of alpha(1B)-adrenoceptors in these contractions after castration. We now investigated the time course of this plasticity and the effects of testosterone by determining the actions of competitive antagonists on noradrenaline-induced contractions after 7, 14, 21 and 30 days of castration. BMY 7378 (8-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-8-azaspiro[4.5]decane-7,9-dione dihydrochloride) antagonised noradrenaline-induced contractions in control and castrated rats with low pA(2) values (congruent to 6.8). In control vas deferens, WB 4101 (2-(2,6-dimethoxyphenoxyethyl)aminomethyl-1,4-benzodioxane hydrochloride) had a slope in the Schild plot no different from 1.0, while slopes lower than 1.0 ( approximate to 0.6) were observed for vas deferens from castrated rats. Chloroethylclonidine was ineffective in the control vas while it inhibited noradrenaline-induced contractions in vasa from castrated rats and converted the complex antagonism by WB 4101 into simple competitive antagonism. Treatment of castrated rats with testosterone prevented the effects of castration. The results suggest that alpha(1B)-adrenoceptors are detectable in vas deferens from at least the 7th through the 30th day after castration and that testosterone prevents this plasticity. (C) 2003 Elsevier B.V. B.V. All rights reserved.

Detection of propranolol in pharmaceutical formulations by diffuse reflectance spectroscopy

This paper describes an analytical reflectometric method that has an objective not only the industrial quality control but also to detect possible falsifications and/or adulterations of propranolol in pharmaceutical formulations. The method is based on the diffuse reflectance measurements of the colored product (III) of the spot test reaction between propranolol hydrochloride (I) and 2,6-dichloroquinone-4-chloroimide (II) using filter paper as solid support. Spot test conditions have been investigated using experimental design in order to identify and optimize the critical factors. The factors evaluated were DCQ concentration, propranolol solvent and DCQ solvent. The best reaction conditions were achieved with the addition of 30 mu L, of propranolol solution in ethanol 35% (v/v) and 30 mu L of DCQ solution at 70 mg mL(-1) in acetone, in this order. All reflectance measurements were carried out at 500 nm and the linear range was from 8.45 x 10(-4) to 8.45 x 10(-2) mol L-1 (r= 0.998). The limit of detection was 1.01 x 10(-4) mol L-1. No interference was observed from the assessed excipients and drugs. The method was applied to determine propranolol in commercial brands of pharmaceuticals. The results obtained by the proposed method were favorably compared with those given by the British Pharmacopoeia procedure. (C) 2007 Elsevier B.V. All rights reserved.

Determination of nitrite in meat products and water using dapsone with combined spot test/diffuse reflectance on filter paper

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Molecular Docking and Molecular Dynamic Studies of Semi-Synthetic Piperidine Alkaloids as Acetylcholinesterase Inhibitors

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Envenomation by scorpion in dog: case report

A case admitted at the Small Animals Clinics Service, Veterinary Hospital, FMVZ - UNESP, in May, 1999 is described. A Brazilian Terrier dog, 3 years and 3 months old, weighing 1.7 kg was brought after 2 hours and a half from contact with a scorpion (Tityus bahiensis). The dog showed vocalization inserted with drowsiness. Physical examination showed slightly hyperemic mucous, pain, agressiveness, tachypnea, tachycardia, and discrete erythema on the right forelimb palmar face. An anesthetic block was performed around the stung area using 2% lidocaine hydrochloride without vasoconstrictor (10mL). The animal was asymptomatic, after 24 h treatment.

Thermal decomposition of some chemotherapic substances

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Electroactive layer-by-layer films of iron tetrasulfonated phthalocyanine

Electroactive films of iron tetrasulfonated phthalocyanine (FeTsPc) were assembled via the electrostatic layer-by-layer technique (LBL), in which FeTsPc layers were alternated with the polycationic poly(allylamine hydrochloride) (PAN). The multilayer formation was monitored via UV-Vis spectroscopy by measuring the increase in the Q Band of FeTsPc at 676 nm. Film thickness was estimated by profilometry as ca. 10 Angstrom per bilayer. Fourier transform infrared and UV-Vis absorption spectroscopy suggested specific interactions between FeTsPc and PAR Cyclic voltammograms showed reproducible pairs of oxidation-reduction peaks at 0.92 mV and 0.70 mV, respectively, for a 50-bilayer PAH/FeTsPc film at 50 mV/s (vs Ag/AgNO3).

Rapid spot test analysis for the detection of urotropine in pharmaceutical preparations

The widespread falsification and/or adulteration of commercially available pharmaceutical preparations call for reliable methods of drug identification, preferably through selective and rapid sorting color tests that could be undertaken with minimum equipment remote from laboratory facilities. The present work deals with a convenient adaptation and refinement of a spot test devised by Feigl (1966) for urotropine, based on the hydrolytic cleavage of that substance in the presence of sulfuric acid, splitting out formaldehyde which is identified by its color reaction with chromotropic acid. A simple emergency kit was developed for the quick, efficient, inexpensive and easy performance of urotropine tests by semiskilled personnel even in the drugstore laboratory (or office) as well as in a mobile screening operation. It is shown that when the reagents are added according to the recommended sequence a self-heating system is generated, increasing substantially the reactions' rates and the test sensitivity as well. The identification limit found was 25 mug of urotropine, for both solid and liquid samples. The possible interference of 84 substances/materials was investigated. Interference was noted only for methylene blue, acriflavine, Ponceau Red, Bordeaux Red (these dyes are often included in urotropine dosage forms), pyramidone, dipyrone, quinine and tetracycline. A simple procedure for removing most of the interferences is described. Data for 8 commercial dosage forms and results obtained from their analysis are presented.

Determination of the betaine content of feed ingredients using high-performance liquid chromatography

A series of studies was conducted to establish a methodology for the accurate and efficient determination of betaine in different feed ingredients. The final methodology involves an extraction step in which the feed sample is heated for 3h in a methanolic KOH solution using a Goldfisch apparatus. Impurities are removed by the addition of activated charcoal and concentrated (36%) HCl. After centrifugation the extractant is passed through a strong cation exchange resin (Dowex 50W-X12, H+). The betaine retained in the column is eluted with 1.5 N HCl. A 2 nil aliquot of the elute is air dried and reconstituted with 1 ml of deionised water. HPLC separation with a cation exchange column (Partisil SCX-10) is used for the separation of betaine from other compounds. The mobile phase is kept constant at 50mm KH2PO4 in water, and eluted compounds are detected by UV absorbance (200nm). The flow rate is maintained at 1.5ml min(-1). This assay is very accurate over the range of betaine concentrations from 15 to 650 mug ml(-1), with a lower detection limit in feeds of approximately 500 mug g(-1) when 4g of sample is extracted. Recovery assays done with standard betaine hydrochloride and hard red wheat resulted in a consistent recovery of 80%. Betaine content was quantified in several feed ingredients, including alfalfa (1.77 mg kg(-1)), wheat (3.96 mg kg(-1)), wheat middlings (4.98 mg kg(-1)) and poultry meal (0.77 mg kg(-1)). Betaine in corn and soybean meal was not detectable by this method, even when 16g of sample was used (<125 mg kg(-1)). Betaine present in several feed ingredients should influence choline supplementation to animal feeds and may have implications for human health. (C) 2002 Society of Chemical Industry.

Nanoscale manipulation of CdSe quantum dots in layer-by-layer films: influence of the host polyelectrolyte on the luminescent properties

Thioglycolic acid-capped Use quantum dots (QDs) were assembled on glass substrates with two distinct polyelectrolytes, viz poly(allylamine hydrochloride) (PAH) and poly(amidoamine) (PAMAM), generation 4 dendrimer, via the layer-by-layer (LbL) technique. Films containing up to 30 polyelectrolyte/QD bilayers were prepared. The growth of the multilayers was monitored with UV-vis spectroscopy, which showed an almost linear increase in the absorbance of the 2.8 nm QDs at 535 nm with the number of deposited bilayers. AFM measurements estimated a film thickness of 3 nm per bilayer for the PAH/Cdse films. The adsorption process and the optical properties of the PAMAM/CdSe LbL films were further analyzed layer-by-layer using surface plasmon resonance (SPR), from which a thickness of 3.2 nm was found for a PAMAM/CdSe bilayer. Photoluminescence measurements revealed higher photooxidation of the quantum dots in PAH/CdSe than in PAMAM/CdSe films. (c) 2004 Elsevier B.V. All rights reserved.