Limewater and Polymyxin B Associated with NaOCl for Endotoxin Detoxification in Root Canal with Necrotic Pulp

Abstract This clinical study investigated the effects of endodontic treatment by using different irrigants (limewater + NaOCl and polymyxin B + NaOCl) and intracanal medication on endotoxins in teeth with primary endodontic infection and radiographically visible apical periodontitis. Thirty-three teeth with necrotic pulp and periapical lesions from different patients were selected for this study. Samples were collected after the coronal opening (S1) and after instrumentation (S2). Root canals were divided in 3 groups (n = 11) according to the irrigant combination used: NaOCl + LW: 2.5% NaOCl + calcium hydroxide solution (0.14%, limewater); NaOCl + PmB: 2.5% NaOCl + 10.000 UI/mL polymyxin B; 2.5% NaOCl (control). The third sampling (S3) was performed after ethylenediaminetetraacetic acid and the fourth (S4) after samples got 14 days with intracanal medication with 2% chlorhexidine gel + calcium hydroxide. Endotoxins (lipopolysaccharide) were quantified by chromogenic Limulus amebocyte lysate (LAL). Endotoxins were detected in all root canals after the coronal opening (S1). NaOCl + PmB group presented the greatest endotoxin reduction after instrumentation (76.17%), similar to NaOCl + LW group (67.64%, p<0.05) and different from NaOCl group (42.17%, p<0.05). After intracanal medication period (S4), there was significant increase of endotoxins neutralization. It was concluded that NaOCl + PmB promoted the greatest reduction of endotoxin levels, followed by NaOCl + LW. Intracanal medications had no significant complementary role in the reduction of endotoxins at the end of the treatment

Resumo Este estudo clínico investigou os efeitos do tratamento endodôntico com uso de diferentes irrigantes (NaOCl + água de cal e NaOCl + polimixina B) e medicação intracanal sobre endotoxinas em dentes com infecção endodôntica primária e presença de lesão periapical visível radiograficamente. Foram selecionados para o estudo trinta e três dentes de pacientes que apresentavam necrose pulpar e presença de lesão periapical. As amostras foram coletadas após a abertura coronária (S1) e após a instrumentação (S2). Os canais radiculares foram divididos em 3 grupos (n = 11) de acordo com a combinação de irrigantes utilizada: NaOCl + LW:- hipoclorito de sódio 2,5% + solução de hidróxido de cálcio (água de cal 0,14%); NaOCl + PmB: hipoclorito de sódio a 2,5% + polimixina B 10.000 UI/mL; NaOCl (controle): hipoclorito de sódio a 2,5%. A terceira coleta (S3) foi realizada após aplicação do ácido etilenodiamino tetra acético (EDTA) e a quarta coleta (S4) após 14 dias de medicação intracanal de hidróxido de cálcio + clorexidina gel 2%. Endotoxinas (lipopolissacarídeos) foram quantificadas pelo ensaio cromogênico do lisado de amebócitos de Limulus (LAL). Endotoxinas foram detectadas em todos os canais radiculares após abertura coronária (S1). Grupo NaOCl + PmB apresentou a maior redução de endotoxinas após a instrumentação (76,17%), sendo similar ao grupo NaOCl + LW (67,64%, P >.05) e diferente do grupo NaOCl (42,17%, P <.05). Após o período de medicação intracanal, houve aumento significativo da neutralização de endotoxinas. Concluiu-se que NaOCl + PmB promoveu a maior redução dos níveis de endotoxinas, seguido de NaOCl + LW. A medicação intracanal não teve um papel complementar significativo na redução de endotoxinas no final do tratamento.

High mobility group box 1 as a mediator of endotoxin administration after hemorrhagic shock-primed lung injury

High mobility group box 1 (HMGB1) was discovered as a novel late-acting cytokine that contributes to acute lung injury (ALI). However, the contribution of HMGB1 to two-hit-induced ALI has not been investigated. To examine the participation of HMGB1 in the pathogenesis of ALI caused by the two-hit hypothesis, endotoxin was injected intratracheally in a hemorrhagic shock-primed ALI mouse model. Concentrations of HMGB1 in the lung of the shock group were markedly increased at 16 h (1.63 ± 0.05, compared to the control group: 1.02 ± 0.03; P < 0.05), with the highest concentration being observed at 24 h. In the sham/lipopolysaccharide group, lung HMGB1 concentrations were found to be markedly increased at 24 h (1.98 ± 0.08, compared to the control group: 1.07 ± 0.03; P < 0.05). Administration of lipopolysaccharide to the hemorrhagic shock group resulted in a notable HMGB1 increase by 4 h, with a further increase by 16 h. Intratracheal lipopolysaccharide injection after hemorrhagic shock resulted in the highest lung leak at 16 h (2.68 ± 0.08, compared to the control group: 1.05 ± 0.04; P < 0.05). Compared to the hemorrhagic shock/lipopolysaccharide mice, blockade of HMGB1 at the same time as lipopolysaccharide injection prevented significantly pulmonary tumor necrosis factor-alpha, interleukin-1beta and myeloperoxidase. Lung leak was also markedly reduced at 16 h; blockade of HMGB1 24 h after lipopolysaccharide injection failed to alter lung leak or myeloperoxidase at 48 h. Our observations suggest that HMGB1 plays a key role as a late mediator when lipopolysaccharide is injected after hemorrhagic shock-primed ALI and the kinetics of its release differs from that of one-hit ALI. The therapeutic window to suppress HMGB1 activity should not be delayed to 24 h after the disease onset.

Intratracheal Administration of Endotoxin Attenuates Hyperoxia-Induced Lung Injury in Neonatal Rats

PURPOSE: This study was undertaken to determine the effects of intratracheal administration of endotoxin on hyperoxia-induced lung injury in neonatal rats. MATERIALS AND METHODS: Newborn Sprague Dawley rat pups were divided into four experimental groups: normoxia control (NC), normoxia with endotoxin treatment (NE), hyperoxia control (HC), and hyperoxia with endotoxin treatment (HE) groups. In HC and HE, rat pups were subjected to 14 days of hyperoxia (> 95% oxygen) within 12 hours after birth. In endotoxin treated group (NE and HE), Escherichia coli endotoxin (0.5microgram in 0.03mL of saline) was given intratracheally at the 1st, 3rd and 5th postnatal day. Radial alveolar count (RAC), mean linear intercept (MLI), RAC/MLI ratios, and degree of fibrosis were measured to assess the changes in lung morphology. RESULTS: During the research period, survival rates in both HC and HE were notably reduced 7 days after endotoxin was administered, but body weight gain was considerably reduced only in HC. On day 14, significant arrest in alveolarization, as evidenced by the decrease of RAC and RAC/MLI ratio and increase of MLI as well as increased fibrosis, were noted in HC. Although slight but significant arrest in alveolarization and increased fibrosis score were observed in NE compared to NC, the hyperoxia-induced lung damage observed in HC was significantly improved in HE. CONCLUSION: This study suggests that intratracheal administration of endotoxin significantly attenuated hyperoxia-induced lung injury in neonatal rats.

Lack of neutrophil degranulation in low-dose endotoxin inhalation based on a novel intracellular assay.

To study the nature of endotoxin or lipopolysaccharide (LPS) induced inflammation, we developed a method of quantifying intracellular human neutrophil elastase (HNE) in lysed sputum polymorphs as a means to study the degranulation status of LPS-recruited neutrophils. Induced sputum, blood and exhaled nitric oxide (NO) were collected from 10 healthy non-atopic human subjects after inhaling a single 15 microg dose of Escherichia coil LPS in an open study. At 6 hours, LPS inhalation caused significant increase of sputum and blood neutrophils but without parallel increase in myeloperoxidase, HNE or interleukin-8 (IL-8) in sputum sol and blood, or exhaled NO. Intracellular HNE in lysed sputum polymorphs or purified blood neutrophils did not show any significant changes between inhaled LPS and saline, nor was there any appreciable change in percentage HNE release induced by N-Formyl-Met-Leu-Phe (fMLP) in vitro. We concluded that in healthy humans, the transient neutrophilic inflammation induced by a single dose of inhaled 15 microg LPS is mainly characterized by cell recruitment, not enhanced secretion of granular mediators or increased exhaled NO based on our experimental conditions.

Análise in vitro da eficácia da impermeabilizaçäo da dentina radicular com verniz tipo copal, em dentes obturados com os cimentos N-Rickert e Sealer-26 e preparados para retentor intra-radicular, empregando método de infiltraçäo e quantificaçäo do nível de endotoxina / Analysis in vitro of effectiveness of the impermeabilization of the root canal dentin with copal varnish in teeth filled with N-Rickert and Sealer-26 cements and prepared for a post using endotoxin level infiltration and quantification method

As pesquisas têm se concentrado nos estudos da microinfiltraçäo marginal apical, empregando diversos métodos, dos quais a penetraçäo linear de um marcador (corante ou radioisótopo) ao longo da obturaçäo do canal tem sido o mais utilizado, entretanto a ocorrência da infiltraçäo por via coronária também pode comprometer o isolamento do meio interno em relaçäo à cavidade bucal. Portanto, o selamento coronário adequado possui grande relevância para o bom êxito do tratamento endodôntico, principalmente nos dentes que necessitam de preparo para inserçäo de retentor intra-radicular. Julgou-se oportuno avaliar a eficácia da impermeabilizaçäo da dentina radicular com verniz tipo copal, em dentes obturados com os cimentos N-Rickert e Sealer-26 e preparados para retentor intra-radicular, com auxílio do método do lisado do amebócito do limulus de detecçäo e quantificaçäo da endotoxina bacteriana (LAL "Endochrome"), o qual possui especificidade para detecçäo de níveis mínimos...

Endotoxin-induced enteric hypomotility in jaundiced loops in vitro

Biliary obstruction may be accompanied by systemic endotoxemia due to increased growth of enteric microbiota and failure of hepatic clearance mechanisms. This endotoxemia is related to increased postoperative morbidity and mortality. An increased growth of the aerobic flora has been demonstrated experimentally in the presence of biliary obstruction, and in previous studies we observed intestinal hypomotility of jaundiced loops in vitro. To determine the ileal motor response in the presence of jaundice caused by biliary obstruction and in the presence of endotoxemia, an in vitro study was carried out on ileal segments from 10 female Holtzman rats, 2-3 months old, weighing 200 to 300 g, divided into two groups (N = 5): A, washed loops of jaundiced rats, and B, washed loops of jaundiced rats to which endotoxin was added. On the seventh postoperative day, we evaluated the effect of exogenous endotoxin (E. coli 0111:B4, Sigma) on the motor response to acetylcholine of distal ileal segments isolated from both animal groups. A 4-cm ileal segment, located 10 cm from the ileal papilla, was removed and studied in an organ chamber in order to assess dose-response curves to acetylcholine. There was an increase in threshold dose in jaundiced loops with intraluminally injected endotoxin when compared with the loops without intraluminal endotoxin (291 + 188 vs 8.5 + 6.7 muM, P<0.05). The maximum contraction was reduced in jaundiced loops with intraluminal endotoxin in relation to control loops (5.3 + 1.7 vs 18.7 + 4.8 mm, P<0.05), and pD2 was also reduced in jaundiced loops with intraluminal endotoxin in relation to control loops (2.4 + 0.6 vs 3.7 + 0.5, P<0.05). There was no statistical difference between jaundiced loops with and without intraluminal endotoxin when the maximal contraction doses were compared (86 + 66 vs 48 + 22 mM, P>0.05). These results demonstrate that intraluminal endotoxin depressed enteric motility in jaundiced rats.

Papel da regiäo AV3V no choque séptico experimental em ratos tratados com NaCl 7, 5 / The role of AV3V region in experimental septic shock, in rats treated with NaCl 7, 5

Nossos resultados mostram que a soluçäo de NaCl7, 5 por cento (SH) possui açäo benéfica no choque circulatório produzido pela injeçäo endovenosa de endotoxina (Etx) em ratos, apresentando um restabelecimento parcial da pressäo média, sendo este efeito abolido em animais com lesäo AV3V. Porém, no choque circulatório severo, produzido por doses altas de Etx, a SH näo foi capaz de causar benefícios, sugerindo que, neste caso, a quantidade de mediadores químicos liberados dos macrófagos pela Etx seja alta, principalmente de óxido nítrico (NO), causando hipotensäo. Estes resultados mostram que a integridade da regiäo AV3V é importante para os efeitos benéficos da SH. É possível que a produçäo e liberaçäo de NO contribua de modo significativo para os efeitos danosos da Etx. Assim, a descoberta dos mecanismos pelos quais esta molécula atua virá possibilitar a prevençäo e o tratamento mais eficaz do choque produzido por endotoxinas

Hipertermia experimental en conejos / Experimental hyperthermia in rabbit

En el presente trabajo se reprodujo y desarrolló un modelo experimental para producir hipertermia en conejos, mediante la administración de LPS de Escherichia coli (0,27:B8 de Sigma Chemical Co., EE.UU.). En la experiencia se utilizaron 15 conejos de 2.500ñ500g sanos, con temperaturas basales con un rango de 38,5 a 39,5§C. Los animales fueron agrupados en tres lotes. Los lotes 1 y 2, constituidos por 6 conejos cada uno y el lote 3 por 3 conejos. A cada animal del lote 1 se le administró vía endovenosa (EV) 0,1 *g/kg de peso de LPS de E. coli, en tanto que el lote 2 recibió 45 min previos al LPS por vía subcutánea (SC), plasma anti-LPS (600*g de inmunoglobulinas precipitantes de LPS/kg de peso corporal), con la finalidad de inhibir el efecto termogénico del LPS. El lote 3 actuó como control. Cada 15 min y durante 6h se registraron, vía rectal, las temperaturas en todos los animales. Los resultados obtenidos muestran que el LPS del serotipo (clase de bacteria) utilizado de E. coli en los lotes 1 y 2, produjo un cuadro de hipertermia durante 5h postadministración. Este presentó disposición bifásica con picos térmicos entre la primera y segunda hora y media postadministración. Los animales que recibieron, en forma previa, al LPS suero anti LPS, registraron temperaturas levemente inferiores (p<0,05). El lote testigo presentó temperatura normal

Endotoxin induces eosinophil accumalation in the rat pleural cavity

Changes in eosinophil counts after intrathoracic (it) injection of endotoxin (LPS) were investigated in Wistar rats (150 - 180 g). Increasing doses of endotoxin (62.5 - 500 ng/cavity) induced a dose-dependent increase in the number of eosinophils recovered from the rat pleural cavity 24 h later. The eosinophilia was apparent within 24 h, peaked within 48 h (from 0.76 ñ 0.12 to 3.68 ñ 0.51 eosinophils x 10**6/cavity, P < 0.001) and returned to basal levels 120h after the it inection of endotoxin (250 ng/cavity). Endotoxin (3 ng - 4 µg/ml) failed to attract eosinophilis in vitro under conditions in which PAF-acether induced a dose-related response. These findings indicate that endotoxin-induced eosinophil migration in vivo is mediated by a secondary mechanism

Efecto de la endotoxina salmonelosica en la conducción auriculo ventricular

Se realizó un estudio longuitudinal, prosprectivo, comparativo, randomizado a doble ciego en 16 pacientes con diagnostico de fiebre tifoidea en base a hemocultivo, divididos en dos grupos: 6 que recibieron placebo y 10 que recibieron verapamil, con el objeto de establecer efecto sinérgico de la endotoxina salmonelósica con el verapamil. Encontrandose que los pacientes que hicieron disociación pulso temperatura desde su ingreso y recibieron verapamil presentaron bloqueo auriculo ventricular (1 paciente). Los que no presentaron disociación y recibieron verapamil prolongaron su PR pero no llegaron a limites patologicos (2 pacientes). El resto de pacientes no presento alteraciones del PR. Por lo que sugerimos el evitar el uso de fármacos que retarden la conducción AV en pacientes con tifoidea y la monitorización de pacientes con trastornos en la conducción AV afectados por tifoidea.