Could polyhexanide and chlorine dioxide be used as an alternative to chlorhexidine? A systematic review

ABSTRACT BACKGROUND: Maintenance of oral microbiota balance is the simplest way to prevent infectious oral diseases, through controlling dental biofilm. Combined use of mouthwash and mechanical removal has been shown to be a very effective way for this. OBJECTIVES: To identify clinical studies comparing the antimicrobial effect and possible adverse effects and/or side effects of chlorhexidine-based mouthwashes with those of mouthwashes containing chlorine dioxide and/or polyhexanide, for controlling oral microbiota. DESIGN AND SETTING: Systematic review designed by the stomatology sector of postgraduation in applied dental sciences of Bauru Dentistry School, University of São Paulo, Brazil. METHODS: A systematic review was conducted using online databases (PubMed, Embase, Web of Science and Science Direct) up to April 8, 2020. The search was conducted using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. RESULTS: The studies included comprised eight articles published between 2001 and 2017. A total of 295 young adults, adults and elderly people were evaluated (males 44.75% and females 55.25%). Three articles compared polyhexanide with chlorhexidine and five articles compared chlorine dioxide with chlorhexidine. No studies comparing all three mouthwashes were found. The concentrations of the study solutions were quite varied, and all rinses had an antimicrobial effect. In four studies, it was stated that no side effects or adverse effects had been found. Three studies did not address these results and only one study addressed side effects and/or adverse effects. CONCLUSION: Mouthwashes containing chlorine dioxide and polyhexanide are viable alternatives to chlorhexidine, since they reduce oral biofilm and have little or no reported side or adverse effects.

Antimicrobial activity of different disinfectants against cariogenic microorganisms

Abstract The aim of this study was to assess the in vitro antimicrobial effects of chlorhexidine digluconate (CHX), polyhexamethylene biguanide (PHBM), and octenidine dihydrochloride (OCT) on cariogenic microorganisms by using their minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). CHX, PHBM, and OCT were diluted in distilled water to the final test concentrations. Using the in-tube dilution method, Streptococcus mutans, Lactobacillus acidophilus, Lactobacillus rhamnosus, and Actinomyces viscosus were cultivated on blood agar and Mueller-Hinton broth (MHB) at 37°C for 48 h. They were read using a spectrophotometer to detect MIC. To determine MBC, samples in the range of the turbidity threshold after 24 h were transferred onto blood agar and evaluated for growth after 24 h. Different MICs and MBCs were observed in all disinfectants against each microorganism. The lowest MIC and MBC against S. mutans (60 mg/L) were obtained from PHBM. The lowest values against L. rhamnosus (15 mg/L, 30 mg/L), A. viscosus (30 mg/L), and L. acidophilus (15 mg/L, 30 mg/L) were determined by OCT. PHBM and OCT have the potential to be replaced with CHX because they were effective against cariogenic microorganisms.

QMix® irrigant reduces lipopolysacharide (LPS) levels in an in vitro model

AbstractThe presence of endotoxin inside the root canal has been associated with periapical inflammation, bone resorption and symptomatic conditions.Objectives To determine, in vitro, the effect of QMix® and other three root canal irrigants in reducing the endotoxin content in root canals.Material and Methods Root canals of single-rooted teeth were prepared. Samples were detoxified with Co-60 irradiation and inoculated with E. coli LPS (24 h, at 37°C). After that period, samples were divided into 4 groups, according to the irrigation solution tested: QMix®, 17% EDTA, 2% chlorhexidine solution (CHX), and 3% sodium hypochlorite (NaOCl). LPS quantification was determined by Limulus Amebocyte Lysate (LAL) assay. The initial counting of endotoxins for all samples, and the determination of LPS levels in non-contaminated teeth and in contaminated teeth exposed only to non-pyrogenic water, were used as controls.Results QMix® reduced LPS levels, with a median value of 1.11 endotoxins units (EU)/mL (p<0.001). NaOCl (25.50 EU/mL), chlorhexidine (44.10 EU/mL) and positive control group (26.80 EU/mL) samples had similar results. Higher levels were found with EDTA (176.00 EU/mL) when compared to positive control (p<0.001). There was no significant difference among EDTA, NaOCl and CHX groups. Negative control group (0.005 EU/mL) had statistically significant lower levels of endotoxins when compared to all test groups (p<0.001).Conclusion QMix® decreased LPS levels when compared to the other groups (p<0.001). 3% NaOCl, 2% CHX and 17% EDTA were not able to significantly reduce the root canal endotoxins load.

Central 5-HT2A receptors modulate the vagal bradycardia in response to activation of the von Bezold-Jarisch reflex in anesthetized rats

Activation of 5-hydroxytryptamine (5-HT) 5-HT1A, 5-HT2C, 5-HT3, and 5-HT7 receptors modulates the excitability of cardiac vagal motoneurones, but the precise role of 5-HT2A/2B receptors in these phenomena is unclear. We report here the effects of intracisternal (ic) administration of selective 5-HT2A/2B antagonists on the vagal bradycardia elicited by activation of the von Bezold-Jarisch reflex with phenylbiguanide. The experiments were performed on urethane-anesthetized male Wistar rats (250-270 g, N = 7-9 per group). The animals were placed in a stereotaxic frame and their atlanto-occipital membrane was exposed to allow ic injections. The rats received atenolol (1 mg/kg, iv) to block the sympathetic component of the reflex bradycardia; 20-min later, the cardiopulmonary reflex was induced with phenylbiguanide (15 µg/kg, iv) injected at 15-min intervals until 3 similar bradycardias were obtained. Ten minutes after the last pre-drug bradycardia, R-96544 (a 5-HT2A antagonist; 0.1 µmol/kg), SB-204741 (a 5-HT2B antagonist; 0.1 µmol/kg) or vehicle was injected ic. The subsequent iv injections of phenylbiguanide were administered 5, 20, 35, and 50 min after the ic injection. The selective 5-HT2A receptor antagonism attenuated the vagal bradycardia and hypotension, with maximal effect at 35 min after the antagonist (pre-drug = -200 ± 11 bpm and -42 ± 3 mmHg; at 35 min = -84 ± 10 bpm and -33 ± 2 mmHg; P < 0.05). Neither the 5-HT2B receptor antagonists nor the vehicle changed the reflex. These data suggest that central 5-HT2A receptors modulate the central pathways of the parasympathetic component of the von Bezold-Jarisch reflex.

Avaliação da ação antimicrobiana de soluções multiuso para desinfecção de lentes de contato hidrofílicas, in vitro / Antimicrobial efficacy assessment of multi-use solution to disinfect hydrophilic contact lens, in vitro

OBJETIVO: Avaliar a influência da ação antimicrobiana das soluções multiuso para desinfecção de lentes de contato hidrofílicas. MÉTODOS: Duas soluções multiuso denominadas solução A (poliquaternário-1 a 0,001 por cento e miristamidopropil dimetilamina a 0,0005 por cento) e solução B (poliaminopropil biguanida a 0,0001 por cento) foram testadas em lentes de contato hidrofílicas contaminadas com Pseudomonas aeruginosa (ATCC27583), Staphylococcus epidermidis (ATCC1226), Klebsiella pneumoniae (ATCC13883), Staphylococcus aureus (ATCC25923) e Candida albicans (ATCC 10231) para verificar a quantidade de redução do crescimento dos microrganismos após o enxágue com as soluções. Foram seguidas as instruções preconizadas pelos fabricantes. RESULTADOS: Houve redução de 90 por cento do crescimento de Pseudomonas aeruginosa, Staphylococcus epidermidis, Staphylococcus aureus e Candida albicans. Não houve crescimento de Klebsiella pneumoniae. CONCLUSÃO: As soluções testadas neste trabalho mostraram redução do número de microrganismos testados.

PURPOSE: To evaluate the efficacy of disinfecting solutions in hydrophilic contact lenses (CL). METHODS: Two multi-use solutions denominated solution A (0.001 percent polyquaternium-1 and 0.0005 percent myristamidopropyl dimethylamine) and solution B (0.0001 percent polyaminopropyl biguanide) were used. The solutions were tested in hydrophilic contact lenses infected with Pseudomonas aeruginosa (ATCC27583), Staphylococcus epidermidis (ATCC1226), Klebsiella pneumoniae (ATCC13883), Staphylococcus aureus (ATCC25923) and Candida albicans (ATCC 10231) and the decrease in microorganisms growth after the hydrophilic contact lenses were cleaned with the respective solutions was verified. The manufacture's instructions were followed. RESULTS: A decrease of 90 percent of Pseudomonas aeruginosa, Staphylococcus epidermidis, Staphylococcus aureus, Candida albicans and a decrease 100 percent of Klebsiella pneumoniae was observed. CONCLUSION: The solutions decreased the amount of microorganisms tested.

5-HT3 receptors in selective animal models of cognition.

Role of 5-HT3 receptors in cholinergic hypofunctional models of cognitive impairment in the elevated plus maze model and a passive avoidance model is studied. Cognitive impairment was caused by scopolamine (1 mg/kg, ip) in mice and 5-HT3 ligands mCPBG (1 and 5 mg/kg, ip) and ondansetron (0.5 and 5 mg/kg, ip) were administered before the pre-learning phase to study the effects on acquisition, while post-learning administration was used to determine the effects on consolidation. Ondansetron improved acquisition and retention in cholinergic hypofunctional models while mCPBG potentiated selected impaired cognitive indices. The results indicate the role of 5-HT3 receptors in cognition and that an ideal evaluation of 5-HT3 ligands in cognition should distinguish true cognitive effects from locomotor, motivational and emotional effects.

Phenyldiguanide activates cardiac receptors to produce responses by involving three different efferent pathways in anaesthetized rats.

The present study was undertaken to determine the afferent and efferent pathways involved in the phenyldiguanide (PDG)-induced reflex response in rats. Intravenous (iv) injection of PDG (10 microg/kg), produced hypotension, bradycardia and apnea over a period of time. Bilateral vagotomy abolished the PDG-induced reflex changes. Atropine (2 mg/kg; iv) blocked only the bradycardiac response produced by PDG, while prazosin (0.5 mg/kg; iv) blocked the hypotensive response, and bilateral vagotomy in these animals abolished the apneic response. In separate series of experiments, intrapericardial injection of lignocaine abolished the hypotensive and bradycardiac responses evoked by PDG in artificially ventilated rats. The results reveal that the PDG-induced reflex is mediated through vagal afferents originating from the heart and efferents involve three different pathways. The bradycardiac response was through the muscarinic receptors, the hypotension is mediated through alpha1 adrenoceptors and the apnea presumably through the spinal motoneurones supplying the respiratory muscles.

Tratamiento farmacológico de la diabetes mellitus tipo 2 / Drug theraphy for the treatment of type 2 diabetes mellitus

El tratamiento farmacológico para los pacientes con diabetes mellitus tipo 2 se encuentra en su estado más maduro, con una base racional, con el principal objetivo de la prevención de la morbilidad y la mortalidad, lo que se encuentra considerado como el distintivo más importante en esta enfermedad. El tratamiento de los pacientes con diabetes mellitus tipo 2 con dieta ocurre en 12 por ciento, con hipoglucemiantes orales en 48 por ciento, con insulina en 36 por ciento, y 4 por ciento tienen un tratamiento combinado de hipoglucemiantes orales e insulina. Durante los últimos años ha habido una gran proliferación de nuevos medicamentos para el tratamiento de los pacientes con diabetes mellitus tipo 2. Estos productos ofrecen diferentes mecanismos de acción, lo que hace importante la individualización del tratamiento. Al momento de prescribir un hipoglucemiante oral debemos tener presente los efectos colaterales y las contraindicaciones

Agentes farmacológicos actuales en el tratamiento de la Diabetes Mellitus no Insulinodependiente / Present pharmacological agents in the treatment of non-insulin-dependent diabetes

Se plantea que debido a la heterogeneidad patogénica de la diabetes mellitus no insulino, se debe considerar que diferentes agentes farmacológicos serán necesarios para tratar con éxito la enfermedad, por lo cual se realiza una revisión bibliográfica de las líneas de tratamiento actuales y en perspectivas para esta compleja entidad. Las modalidades terpéuticas actuales incluyen 5 grupos de agentes esenciales: los inhibidores de las alfaglucosidasas intestinales, las sulfonilureas, las biguanidas, la insulina y el recién incorporado grupo de las tiazolidinedionas, que si se utilizan en los comienzos de la enfermedad o en pacientes con resistencia insulínica, pudieran retrasar o prevenir el desarrollo de ésta, y pueden interferir en la reducción progresiva de la función pancreática. Se expone un grupo importante de agentes farmacológicos, así como sus posibles mecanismos de acción, sobre los cuales se ha estado investigando, para ampliar e incrementar la terapéutica de la diabetes, entre los que se encuentran los análogos de la insulina, los agentes insulinomiméticos y los preparados orales de insulina, los agentes insulinotrópicos no sulfonilureas, los análogos de la amilina, los péptidos similares al glucagón, los antagonistas alfa-2 adrenérgicos, los moduladores del metabolismo de la glucosa y algunas sustancias de origen vegetal con posibles efectos hipoglucémicos

Tratamiento farmacológico de la diabetes mellitus no insulinodependiente / Pharmacological therapy of non insulin dependent diabetes mellitus

Se describe la terapéutica farmacológica en la diabetes mellitus no dependiente de insulina (sulfonilureas, biguanidas, acarbosa e insulina). Se comentan sus mecanismos de acción, efectos secundarios y la necesidad de individualizar el tratamiento de acuerdo con el factor patogénico predominante en la hiperglucemia

Augmentation of phenyldiguanide-induced bradycardia by Buthus tamulus venom in adult rats.

Intravenous injection of phenyldiguanide (PDG) in anaesthetized rats produced dose-dependent (1-10 micrograms/kg) decrease in heart rate for a period of time (time-response area). The maximum response occurred at 10 micrograms/kg PDG. Administration of B. tamulus (BT) venom as low as 20 micrograms/kg augmented the PDG-induced bradycardia response by 2.5 times the initial PDG (10 micrograms/kg) response. The maximal augmentation was observed after 60 min of venom injection. Increasing the BT venom concentration to 40 micrograms/kg failed to enhance the reflex response (1.7 times the initial response). The threshold concentration of BT venom was 4 micrograms/kg. BT venom (100 micrograms/kg) alone, decreased the heart rate significantly only after 90 min. Results indicate that, even the sublethal concentrations of BT venom sensitize the reflexes elicited by PDG.

Hipoglicemiantes orais / Oral Hipoglycemic agentes

Os hipoglicemiantes orais säo representados pelas sulfoniluréias e as biguanidas. As sulfoniluréias agem estimulando as células beta das ilhotas de Langerhans para a secreçäo de insulina e as biguanidas diminuindo a absorçäo de glicose ao nível do trato gastrointestinal. Dentre as sulfoniluréias temos as de primeira geraçäo com açäo mais prolongada e as de segunda geraçäo, 10 a 20 vezes mais potentes, mas com meia vida plasmática mais curta. Todas, com exceçäo da gliquidona, säo eliminadas por via renal, e assim contraindicadas em pacientes urêmicos. O uso das biguanidas está proibido nos E. U. A. e Inglaterra, mas no Brasil ainda estäo sendo comercializadas, mas devem ser usadas com cautela, pois existe o risco de acidose lática em pacientes predispostos a estados de anóxia. Os hipoglicemiantes orais estäo indicados nos pacientes portadores de diabetes mellitus tipo II, insulino independentes, que ainda têm capacidade pancreática para secretar insulina

Limitations in the use of CO2 as a method for studying the J-reflex.

In order to study the J-reflex, monosynaptic reflexes were recorded from L7 or S1 ventral root after stimulation of the posterior biceps, and semi-tendinosus nerve (PBST) from the lower limb in cats anaesthetized with Pentobarbitone sodium. Intratracheal CO2 (60 ml, 100%) depressed the monosynaptic reflexes, and the depression was comparable to the effects of right atrial phenyl diguanide injection. Bilateral vagotomy did not abolish the response showing that the afferent pathway of this depression does not travel via the vagus nerve. Thus it is concluded that CO2 cannot be used to study the J-reflex.