In vivo study of the action of a topical anti-inflammatory drug in rat teeth submitted to dental bleaching

Abstract Bleaching gel containing hydrogen peroxide (H2O2) cause damages in pulp tissue. This study investigated the action of a topical anti-inflammatory, the Otosporin®, in rats' bleached teeth with the null hypothesis of which the Otosporin® is no able to minimize the pulp inflammation that bleaching gel generates. The rat's molars were divided into groups: BLE: bleached (35% H2O2 concentration /single application of 30 min); BLE-O: bleached followed by Otosporin® (10 min); and control: placebo gel. In the second day after dental bleaching, the rats were killed, and the jaws were processed for hematoxylin-eosin and immunohistochemistry analysis for tumor necrosis factor alpha (TNF-α), interleukin (IL)-6 and IL-17. The data collected were subjected to Kruskal-Wallis and Dunn statistical tests with at a 5% level of significance (p<0.05). The BLE group had moderate to strong inflammation in the occlusal third of the coronary pulp, with necrotic areas; and BLE-O, mild inflammation (p<0.05). There was a significant difference in the occlusal and middle thirds of the coronary pulp between the BLE with BLE-O and control groups (p<0.05). There was no difference in the cervical third (p>0.05). The BLE group had a high immunoexpression of TNF-α than BLE-O and control groups (p<0.05), with moderate and mild immunoexpression, respectively. Regarding IL-6 and IL-17, the BLE group had higher immunoexpression than control (p<0.05); the BLE-O was similar to the control (p>0.05). The topical anti-inflammatory Otosporin® can reduce pulp inflammation after dental bleaching in the rat teeth.

Resumo O gel clareador à base de peróxido de hidrogênio (H2O2) causa danos ao tecido pulpar. Este estudo investigou a ação de um anti-inflamatório tópico, o Otosporin®, nos dentes de ratos clareados com a hipótese nula de que o Otosporin® não é capaz de minimizar a inflamação da polpa gerada pelo gel clareador. Os molares dos ratos foram divididos em grupos: ClA: clareado (H2O2 a 35% / aplicação única de 30 min); CLA-O: clareado seguido do Otosporin® (10 min); e controle: gel placebo. No segundo dia após a clareação dentária, os ratos foram mortos e suas maxilas foram processadas para análise de hematoxilina-eosina e imunohistoquímica para o fator de necrose tumoral alfa (TNF-a), interleucina (IL)-6 e IL-17. Os dados coletados foram submetidos aos testes estatísticos de Kruskal-Wallis e Dunn com um nível de significância de 5% (p<0,05). O grupo CLA apresentou inflamação moderada à severa no terço oclusal da polpa coronária, com áreas necróticas; e CLA-O, inflamação leve (p<0,05). Houve diferença significativa nos terços oclusal e médio da polpa coronária entre o grupo CLA com os grupos CLA-O e controle (p<0,05). Não houve diferença no terço cervical (p>0,05). O grupo CLA apresentou maior imunoexpressão para TNF-a comparado aos grupos CLA-O e controle (p<0,05), com imunoexpressão moderada e leve, respectivamente. Em relação a IL-6 e IL-17, o grupo CLA apresentou maior imunoexpressão comparado ao controle (p<0,05); o CLA-O foi semelhante ao controle (p>0,05). O anti-inflamatório tópico Otosporin® pode reduzir a inflamação pulpar após clareação em dentes de ratos.

Antimicrobial activity evaluation and comparison of methods of susceptibility for Klebsiella pneumoniae carbapenemase (KPC)-producing Enterobacter spp. isolates

Abstract The production of KPC (Klebsiella pneumoniae carbapenemase) is the major mechanism of resistance to carbapenem agents in enterobacterias. In this context, forty KPC-producing Enterobacter spp. clinical isolates were studied. It was evaluated the activity of antimicrobial agents: polymyxin B, tigecycline, ertapenem, imipenem and meropenem, and was performed a comparison of the methodologies used to determine the susceptibility: broth microdilution, Etest® (bioMérieux), Vitek 2® automated system (bioMérieux) and disc diffusion. It was calculated the minimum inhibitory concentration (MIC) for each antimicrobial and polymyxin B showed the lowest concentrations for broth microdilution. Errors also were calculated among the techniques, tigecycline and ertapenem were the antibiotics with the largest and the lower number of discrepancies, respectively. Moreover, Vitek 2® automated system was the method most similar compared to the broth microdilution. Therefore, is important to evaluate the performance of new methods in comparison to the reference method, broth microdilution.

Antimicrobial activity of different filling pastes for deciduous tooth treatment

Guedes-Pinto paste is the filling material most employed in Brazil for endodontic treatment of deciduous teeth; however, the Rifocort® ointment has been removed. Thus, the aim of this study was to investigate the antimicrobial potential of filling pastes, by proposing three new pharmacological associations to replace Rifocort® ointment with drugs of already established antimicrobial power: Nebacetin® ointment, 2% Chlorhexidine Gluconate gel, and Maxitrol® ointment. A paste composed of Iodoform, Rifocort® ointment and Camphorated Paramonochlorophenol (CPC) was employed as the gold standard (G1). The other associations were: Iodoform, Nebacetin® ointment and CPC (G2); Iodoform, 2% Chlorhexidine Digluconate gel and CPC (G3); Iodoform, Maxitrol® ointment and CPC (G4). The associations were tested for Staphylococcus aureus (S. aureus), Streptococcus mutans (S. mutans), Streptococcus oralis (S. oralis), Enterococcus faecalis (E. faecalis), Escherichia coli (E. coli), and Bacillus subtilis (B. subtilis), using the methods of dilution on solid medium – orifice agar – and broth dilution. The results were tested using statistical analysis ANOVA and Kruskal-Wallis. They showed that all the pastes had a bacteriostatic effect on all the microorganisms, without any statistically significant difference, compared with G1. S. aureus was statistically significant (multiple comparison test of Tukey), insofar as G2 and G3 presented the worst and the best performance, respectively. All associations were bactericidal for E. coli, S. aureus, S. mutans and S. oralis. Only G3 and G4 were bactericidal for E. faecalis, whereas no product was bactericidal for B. subtilis. Thus, the tested pastes have antimicrobial potential and have proved acceptable for endodontic treatment of primary teeth.

Effect of Trimetaphosphate and Fluoride Association on Hydroxyapatite Dissolution and Precipitation In Vitro

The present study analyzed the action of sodium trimetaphosphate (TMP) and/or fluoride on hydroxyapatite. Hydroxyapatite powder was suspended in different solutions: deionized water, 500 µg F/mL, 1,100 µg F/mL, 1%TMP, 3%TMP, 500 µg F/mL plus 1%TMP and 500 µg F/mL plus 3%TMP. The pH value of the solutions was reduced to 4.0 and after 30 min, raised to 7.0 (three times). After pH-cycling, the samples were analyzed by X-ray diffraction and infrared spectroscopy. The concentrations of calcium fluoride, fluoride, calcium and phosphorus were also determined. Adding 1% or 3% TMP to the solution containing 500 µg F/mL produced a higher quantity of calcium fluoride compared to samples prepared in a 1,100 µg F/mL solution. Regarding the calcium concentration, samples prepared in solutions of 1,100 µg F/mL and 500 µg F/mL plus TMP were statistically similar and showed higher values. Using solutions of 1,100 µg F/mL and 500 µg F/mL plus TMP resulted in a calcium/phosphorus ratio close to that of hydroxyapatite. It is concluded that the association of TMP and fluoride favored the precipitation of a more stable hydroxyapatite.

O presente estudo avaliou a ação do trimetafosfato de sódio (TMP) e/ou fluoreto sobre a hidroxiapatita. Pó de hidroxiapatita foi suspenso em diferentes soluções: água deionizada, 500 µg F/mL, 1100 µg F/mL, 1%TMP, 3%TMP, 500 µg F/mL adicionado a 1%TMP e 500 µg F/mL associado a 3%TMP. O pH das soluções foi reduzido para 4,0 e depois de 30 min, elevado para 7,0 (três vezes). Depois do processo de ciclagem de pH, as amostras foram analisadas por difração de raios-X e espectroscopia por infravermelho. As concentrações de fluoreto de cálcio, fluoreto, cálcio e fósforo também foram determinadas. A adição de 1% ou 3% TMP na solução contendo 500 µg F/mL produziu uma maior quantidade de fluoreto de cálcio comparado às amostras tratadas com uma solução de 1100 µg F/mL. A respeito da concentração de cálcio, amostras tratadas com soluções de 1100 µg F/mL e 500 µg F/mL adicionado ao TMP foram estatisticamente similares e mostraram maiores valores. Soluções de 1100 µg F/mL e 500 µg F/mL adicionado ao TMP resultaram em uma proporção molar Ca/P mais próxima à da hidroxiapatita. Conclui-se que a associação de TMP e F favoreceu a precipitação de uma hidroxiapatita mais estável.

In vitro evaluation of the action of irrigating solutions associated with intracanal medications on Escherichia coli and its endotoxin in root canals

OBJECTIVE: The purpose of this study was to evaluate the effcacy of auxiliary chemical substances and intracanal medications on Escherichia coli and its endotoxin in root canals. MATERIAL AND METHODS: Teeth were contaminated with a suspension of E. coli for 14 days and divided into 3 groups according to the auxiliary chemical substance used: G1) 2.5 percent sodium hypochlorite (NaOCl); G2) 2 percent chlorhexidine gel (CLX); G3) pyrogenfree solution. After, these groups were subdivided according to the intracanal medication (ICM): A) Calcium hydroxide paste (Calen®), B) polymyxin B, and C) Calcium hydroxide paste+2 percent CLX gel. For the control group (G4), pyrogen-free saline solution was used without application of intracanal medication. Samples of the root canal content were collected immediately after biomechanical preparation (BMP), at 7 days after BMP, after 14 days of intracanal medication activity, and 7 days after removal of intracanal medication. The following aspects were evaluated for all collections: a) antimicrobial activity; b) quantifcation of endotoxin by the Limulus Amebocyte Lysate test (LAL). Results were analyzed by the Kruskal-Wallis and Dunn's tests at 5 percent signifcance level. RESULTS: The 2.5 percent NaOCl and CLX were able to eliminate E. coli from root canal lumen and reduced the amount of endotoxin compared to saline. CONCLUSIONS: It was concluded that 2.5 percent NaOCl and CLX were effective in eliminating E. coli. Only the studied intracanal medications were to reduce the amount of endotoxin present in the root canals, regardless of the irrigant used.

Schistosoma mansoni antigen-driven interleukin-10 production in infected asthmatic individuals

Asthmatics infected with Schistosoma mansoni have a less severe course of asthma and an inhibition of the Th2 inflammatory response that seems to be mediated by interleukin (IL-10). The objective of this study was to evaluate the capacity of some S. mansoni antigens to stimulate IL-10 production in vitro by cells of asthmatic infected individuals. Peripheral bloods mononuclear cells were stimulated with the S. mansoni recombinant antigens Sm22.6, Sm14, P24, and PIII antigen. IL-10 was measured in the supernatants of cultures. As the recombinant antigens were cloned in Escherichia coli, we blocked contaminant endotoxin with polymyxin B added to the cultures. We demonstrated that all antigens used drove high production of IL-10 in S. mansoni infected individuals (n = 13, 408 ± 514 and 401 ± 383 pg/ml, 484 ± 245 pg/ml, 579 ± 468 pg/ml, respectively). In asthmatics infected with S. mansoni (n = 21) rP24 induced higher levels of IL-10 (565 ± 377 pg/ml) when compared to PIII, rSm14 and rSm22.6 (184 ± 209 pg/ml; 292 ± 243 pg/ml; 156 ± 247 pg/ml, respectively). Conclusion: the S. mansoni antigens evaluated in this study stimulated IL-10 production by cells from infected individuals and therefore they have the potential to be used as a modulator of the inflammatory response in asthma.

A clinicomicrobiological study on the importance of pseudomonas in nosocomially infected ICU patients, with special reference to metallo beta1-lactamase production.

The present study was conducted with a view to assess the burden of pseudomonal infection in ICU patients of a tertiary care teaching hospital in Uttaranchal. Of the 525 patients selected for the study, during a 1-year period, 60 patients developed features of nosocomial infection and among them Pseudomonas was isolated from one or more samples in 18 patients. The isolated strains were speciated and further characterized for determining their antibiogram and for production of beta-lactamase, extended spectrum beta-lactamase and metallo-beta-lactamase enzymes. Pseudomonas aeruginosa was the commonest species isolated (54.54%) and endotracheal suction material showed the highest bacterial yield. Polymyxin B was found to be the most effective antibiotic followed by imipenem and carbenicillin. Though no strain was found to be producing beta-lactamase and extended spectrum beta-lactamase enzymes, a total of 12 strains (54.54%) were metallo-beta-lactamase producers. For all the beta lactam antibiotics, excepting aztreonam, the metallo-beta-lactamase producers showed more resistance compared to the non-producers.

Induction of proliferation in resting B-cells by a factor released by activated mouse spleen cells

Mouse spleen cells activated in a mixed lymphocyte reaction release a soluble factor, which induces a significant proliferative response in fresh mouse spleen cells. This proliferation inducing factor (PIF) was found to be heat stable (90 degrees C for 45 min) and also resistant to trypsin or chymotrypsin treatment. By using a sizing HPLC column, the molecular weight of PIF appears to be 25 kDa. Mouse spleen cells treated with anti-thy-1 + complement lost Con-A induced proliferative responses but responded well to PIF. B cell depleted spleen cells obtained by negative selection panning, did not respond to PIF. These results indicate that B cells proliferated in response to PIF. Polymixin-B, which blocks the B cell proliferative response to LPS, did not inhibit PIF induced proliferation.

Comparison between the multiplex PCR, sensitivity to biotype specific phages & polymyxin B for biotyping of Vibrio cholerae O1.

A total of 196 Vibrio cholerae O1 strains isolated between 1970 and 1996 were biotyped by multiplex PCR, susceptibility to polymyxin B and sensitivity to biotype specific phages. We modified the multiplex PCR by increasing the primer concentration of tcpA to improve the results. Comparison of the results of modified multiplex PCR and sensitivity to biotype specific phages and to polymyxin B showed that multiplex PCR was as efficient as phage typing for biotyping of V. cholerae O1. All the strains of V. cholerae O1 could be accurately distinguished based on polymyxin B sensitivity. Thus our results show that susceptibility of strains of V. cholerae O1 to polymyxin B is the easiest method to biotype V. cholerae O1 and is feasible in most laboratories when compared with multiplex PCR and sensitivity to biotype specific phages.

Cytotoxigenicity in Salmonella serovars.

Twenty two strains of Salmonella belonging to eight different serovars, namely S. enterica subsp. enterica serovar S. typhimurium, S. nchanga, S. newport, S. virchow, S. bovismorbificans, S. seftenberg, S. weltevreden and S. indiana, isolated from foods of animal origin, were tested for their cytotoxicity on MDBK and Vero cell-lines. Although all the strains were found to be cytotoxic for both the cell-lines, their cytotoxic activity varied greatly. A dose-related cytotoxic effect was observed. Polymyxin B sulphate @.25 mg/ml in PBS, pH 7.2), urea (8M in Tris-HCl buffer, pH 8.2) and cell-sonication were found to augment the release of cytotoxin.

Characterization of bacillus polymyxa isolates from different Brazilian soils

Setenta e oito isolados de B. polymyxa foram obtidos de diferentes solos brasileiros com intuito de se identificar estirpes com marcadores geneticos que pudessem ser utilizadas em experimentos de troca gênica nesta espécie de Bacillus. O DNA destes isolados foi extraído e observou-se que 4 deles apresentavam um plasmídio de tamanho semelhante. Trinta e dois isolados (incluindo os 4 contendo plasmídio) foram escolhidos para estudos complementares. Todos eles mostraram-se resistentes à polimixina-B e à bacitracina e sensíveis aos outros 12 antibióticos testados. Todos os isolados produziram uma substância inibitória contra uma estirpe de Staphylococcus aureus RN45O e 7 contra uma estirpe de Pseudomonas sp. Dos 32 isolados, 25 mostraram-se sensíveis ao fago EPy-2, específico para B.polymyxa, e 2 foram capazes de fixar o nitrogênio atomosférico (teste de reduçäo de acetileno). Entretanto, nenhuma destas características acima mencionadas pode ser atribuída à presença do plasmídio, já que isolados curados (sem o plasmídio) apresentavam as mesmas características fenotípicas que aqueles contendo o plasmídio em questäo

Efecto de polimixina B sobre el mecanismo hemolítico del género Listeria / Effect of polymyxin B on the hemolytic mechanism of the genus Listeria

El contacto de polimixina B, sobre hematíes humanos produjo un efecto sobre la actividad hemolítica de las hemolisinas del género Listeria. A bajas concentraciones de antibiótico, se observó un efecto promotor de la hemólisis; verificándose una inhibición de la lisis eritrocitaria a altas concentraciones de polimixina B. Este comportamiento permitió definir perfiles hemolíticos para cada una de las especies hemolíticas del género en estudio. Listeria monocytogenes y Listeria seeligeri presentaron perfiles superponibles con un máximo hemolítico a 1.000 U/ml de polimixina B. Listeria ivanovii presentó dos picos hemolíticos: uno coincidente con aquél presentado por Listeria monocytogenes y Listeria seeligeri a 1.000 U/ml y un segundo pico a 4.000 U/ml de polimixina B

Avaliaçäo da sensibilidade "in vitro" à associaçäo de sulfato de framicetina, sulfato de polimixina B e gramicidina / Evaluation of the sensibility \"in vitro\" to the association of framycetin sulfate, polymyxin B sulfate and gramicidin

A fim de avaliar a sensibilidade "in vitro" à associaçäo de sulfato de framicetina, sulfato de polimixina B e gramicidina, estudamos amostras de 96 pacientes portadores de patologias oculares externas e de 4 lentes de contato gelatinosas. De 112 antibiogramas realizados, 80 (71,4%) foram por Staphylococcus aureus, cuja sensibilidade incluindo todas as bactérias de 85,7% (96). Esta associaçäo é composta por 3 antibióticos bactericidas näo usados sistematicamente de rotina