Cytotoxicity of intracanal dressings on apical papilla cells differ upon activation with E. faecalis LTA

Abstract Objective The aim of this study was to investigate the cytotoxic effects of modified triple antibiotic paste and an experimental composition using calcium hydroxide on lipoteichoic acid (LTA)-primed apical papilla cells (APC). Material and Methods Human APC were tested for in vitro cytotoxicity of modified Triple Antibiotic Paste (mTAP - Ciprofloxacin, Metronidazole and Cefaclor at 1:1:1) and of a paste of Ciprofloxacin, Metronidazole and Calcium hydroxide (CMC - 1:1:2) and modified CMC (mCMC - 2:2:1) by using MTT assay. The substances were reconstituted in DMEM at 1,000 µg/mL and » serially diluted before being kept in contact with cells for 1, 3, 5 and 7 days. Further, cells were primed with 1 µg/mL of Enterococcus faecalis LTA for 7 days prior to the viability test with 1,000 µg/mL of each substance. Statistical analysis was performed using one-way analysis of variance (ANOVA) and two-way ANOVA respectively followed by Tukey's post-test. Significance levels were set at p<0.05. Results In the first assay, the higher cytotoxic rates were reached by mTAP for all experimental periods. CMC was found toxic for APC at 5 and 7 days, whereas mCMC did not affect the cell viability. Only CMC and mCMC were able to induce some cellular proliferation. In the second assay, when considering the condition with medium only, LTA-primed cells significantly proliferated in comparison to LTA-untreated ones. At this context, mTAP and CMC showed similar cytotoxicity than the observed for LTA-untreated cells, while mCMC was shown cytotoxic at 7 days only for LTA-primed APC. Comparing the medications, mTAP was more cytotoxic than CMC and mCMC. Conclusion mTAP showed higher cytotoxicity than CMC and mCMC and the effect of topic antimicrobials might differ when tested against apical papilla cells under physiological or activated conditions.

Frecuencia de mutaciones de la nitrorreductasa RdxA de Helicobacter pylori para la activación del metronidazol en una población del departamento del Cauca, Colombia / Frequency of Helicobacter pylori nitroreductase RdxA mutations for metronidazole activation in a population in the Cauca Department, Colombia

RESUMEN Introducción. La resistencia al metronidazol es un factor clave relacionado con el fracaso del tratamiento contra la infección por Helicobacter pylori asociada, principalmente, con mutaciones en la nitrorreductasa RdxA. A pesar de su importancia, los estudios sobre esta proteína son aún incipientes en Popayán, Colombia. Objetivo. Evaluar la frecuencia de las mutaciones en la nitrorreductasa RdxA en una población de pacientes con enfermedad gastrointestinal por H. pylori. Materiales y métodos. El ADN de 170 biopsias gástricas se amplificó mediante reacción en cadena de la polimerasa (PCR) para detectar las mutaciones en la nitrorreductasa RdxA. Se analizaron las secuencias traducidas a aminoácidos y se compararon con la cepa de referencia 26695. Resultados. La frecuencia de mutaciones de la nitrorreductasa RdxA en la población de estudio fue de 78 %. Su distribución más frecuente se detectó en las posiciones D59N (en 153 muestras), R131K (en 101 muestras), R90K (en 97 muestras), A118T (en 42 muestras), I160F (en 32 muestras), H97T (en 26 muestras) y en los codones de parada Q50*; D59*; E75*; C159* y I160* en cinco, una, tres, diez y seis muestras, respectivamente. El genotipo de virulencia más frecuente fue el vacAs1/m1 negativo para cagA (48,6 %). Conclusiones. La gran frecuencia de mutaciones en la nitrorreductasa RdxA en aislamientos de H. pylori en Popayán sugiere que los tratamientos empíricos con metronidazol no serían una opción válida para su erradicación en pacientes de la población estudiada.

ABSTRACT Introduction: Resistance to metronidazole is a key factor associated with Helicobacter pylori treatment failure. Even though resistance is mostly associated with RdxA nitroreductase mutations, studies of this H. pylori protein in Popayán (Colombia) are still incipient. Objective: To evaluate the frequency of mutations in the RdxA nitroreductase in a population of patients with H. pylori-positive gastrointestinal disease. Materials and methods: We amplified the DNA of 170 gastric biopsies by PCR to detect mutations in the RdxA nitroreductase. An analysis of DNA sequences translated into amino acid sequences was done and then compared to the reference strain 26695. Results: The frequency of RdxA nitroreductase mutations in this study population was 78%. Its most frequent distribution was found in positions D59N (153 samples), R131K (101 samples), R90K (97 samples), A118T (42 samples), I160F (32 samples) and H97T (26 samples), and meaningful stop codons Q50*, D59*; E75*, C159* and I160* in five, one, three, ten and six samples, respectively. The most common virulence genotype was vacAs1/m1 cagA negative (48.6 %). Conclusions: The high frequency of RdxA nitroreductase mutations in H. pylori isolates in Popayán (Colombia) indicates that empirical therapy with metronidazole may not be a valid option for the eradication of H. pylori in patients of the studied population.

Effect of irrigation technique for removal of triple antibiotic paste on bond strength of MTA to root dentin

Abstract This study evaluated the bond strength of mineral trioxide aggregate (MTA) to root canal dentin after the performance of various irrigation procedures to remove triple antibiotic paste (TAP). A total of 56 single-rooted human mandibular premolars were instrumented using a rotary system to size 40 and divided randomly into a control group (no intracanal dressing) and three experimental groups (TAP application for 28 days). TAP was then removed by rinsing with 10 mL 2.5% NaOCl using three irrigation systems (Vibringe sonic irrigation, CanalBrush, and syringe irrigation). The coronal and middle parts of root canals were then obturated with MTA. After storage for 1 week, each specimen was embedded in an acrylic block and sectioned horizontally (2-mm-thick slices) at two levels (coronal and middle). Bond strength of MTA to root canal dentin was assessed in 28 samples per group via push-out test using a universal testing machine. Data from the four groups were compared using one-way analysis of variance. Tukey's test was used for multiple comparisons. Push-out bond strength values were significantly higher in the control and Vibringe groups than in the CanalBrush and syringe irrigation groups (p < 0.001). TAP removal from root canals with the Vibringe irrigation system may increase the push-out bond strength of MTA compared with the use of the CanalBrush or syringe irrigation.

Chromatographic methods for simultaneous determination of diiodohydroxyquinoline and Metronidazole in their binary mixture

Two chromatographic methods were developed for analysis ofdiiodohydroxyquinoline [DIHQ] and metronidazole [MTN]. In the first method, diiodohydroxyquinoline and metronidazole were separated on TLC silica gel 60F254 plate using chloroform: acetone: glacial acetic acid [7.5: 2.5: 0.1, by volume] as mobile phase. The obtained bands were then scanned at 254 nm. The second method is a RP-HPLC method in which diiodohydroxyquinoline and metronidazole were separated on a reversed-phase C18 column using water: methanol [60 :40, V/V, PH=3.6] as mobile phase at a flow rate of 0.7 mL.min[-1] and UV detection at 220 nm. The mentioned methods were successfully used for determination of diiodohydroxyquinoline and metronidazole in pure form and in their pharmaceutical formulation

Physical and release properties of metronidazole suppositories

Purpose: A study was made of the effects of some bases and adjuvants on the physical and release properties of metronidazole suppositories with a view to providing more information for the optimization of the rectal formulation of metronidazole. Method: Suppositories (1g) containing 200mg of metronidazole each were prepared in witepsol (H15 and E75) and polyethylene glycol (PEG 2850 and 4650) bases; using different concentrations of Tween 80; sodium salicylate and methylcellulose as adjuvants. The setting time; solidification point and melting range of the suppositories were determined; along with their crushing strength; disintegration time and the time for 80of metronidazole to be released from the suppositories (t80). Results: The ranking of setting time for the suppositories was witepsol H15 PEG 2850 witepsol E75 PEG 4650; while the ranking of solidification point; melting range; crushing strength; disintegration time and the time for 80of metronidazole to be released from the suppositories (t80) was the reverse of that for setting time. Optimal concentrations of Tween 80 and sodium salicylate were observed for the suppository formulations. Using Kitazawa plots; all formulations showed two dissolution rate constants; k1 and k2 intersecting at time t1; with formulations containing 5 to 20w/w of methylcellulose exhibiting a third dissolution rate constant; k3 intersecting with k2 at time t2. Conclusion: The physical and release properties of metronidazole sup-positories are influenced considerably by the bases and adjuvants employed. Tween 80 and sodium salicylate can probably be used to formulate only immediate-release supposi- tories while methylcellulose can be useful for sustained-release metronidazole suppositories. Some insight into these inferences can be obtained from parameters derived from Kitazawa plots

Absceso hepático amibiano: experiencia en los últimos cinco años en el Hospital Central Militar / Amebic liver abscess: experience of five years

Se revisaron los expedientes clínicos de 69 pacientes con diagnóstico de absceso hepático amibiano, hospitalizados de enero de 1994 a mayo de 1999 en el Hospital Central Militar.De los 69 casos estudiados 53 (76.8 por ciento) correspondieron al sexo masculino y 16 (23.2 por ciento) al sexo femenino (relación 3:1). La edad mínima fue de 14 años y la máxima de 87, (promedio 47 años). El promedio de enfermos estudiados por año fue de 11 pacientes. Los datos clínicos más frecuentes fueron dolor en hipocondrio derecho en todos los pacientes (100 por ciento), fiebre en 63 pacientes (91.3 por ciento) y malestar general dentro del cual se integran la astenia y la adinamia, en 62 pacientes (90 por ciento). La sensibilidad del ultrasonido fue del 100 por ciento.En todos los pacientes se inició tratamiento médico desde el momento del diagnóstico por USG con metronidazol y combinándose metronidazol más una cefalosporina si el paciente presentaba enfermedad concomitante (diabetes mellitus, reincidencia del absceso, etc.); en 36 pacientes (52 por ciento). Se realizó drenaje del absceso a 44 pacientes, de los cuales 29 pacientes fueron puncionados guiados por USG, presentando reincidencia en 8 pacientes y por drenaje percutáneo se manejaron 15 pacientes con dos reincidencias. Hubo falla del tratamiento médico 12 casos (17.3 por ciento).Con relación a las complicaciones se presentaron 2 casos con abdomen agudo de ingreso por perforación del absceso a cavidad abdominal los cuales fueron llevados a laparotomía exploradora de urgencia y un caso con apertura a bronquios en el cual el manejo fue conservador, la mortalidad fue del 0 por ciento en toda la serie.

Novos quimioterápicos antiparasitários: albendazol e secnidazol / A news chemotherapics agents (drugs) for treatment of parasites infections: albendazole and secnidazole

Os autores descrevem dois novos quimioterápicos empregados no tratamento das parasitoses - Albendazol e Secnidazol -, destacando sobretudo suas aplicaçöes clínicas e seus efeitos colaterais