Resistencia de unión a la dentina de dos cementos selladores de endodoncia después de la medicación intraconducto de hidróxido de calcio con dos tipos de vehículos / Dentin bond strength of two endodontic sealers after intracanal medication of calcium hydroxide with two types of vehicle

Objetivo: Comparar la resistencia de unión a la dentina del cemento sellador tipo Grossman (Grossdent) y Apexit Plus (Ivoclar Vivadent) después de la medicación intraconducto de hidróxido de calcio Ca(OH)2 con vehículos de paramonoclorofenol alcanforado (PMCFA) y de clorhexidina al 2% (CHX). Metodología: Estudio experimental in vitro. Se seleccionó una muestra de 44 dientes humanos monorradiculares y fueron divididos en 4 grupos con medicación intraconducto (n = 9) y 2 grupos control. Los dientes fueron desinfectados y los conductos radiculares instrumentados usando una técnica híbrida. Se medicaron dos grupos con hidróxido de calcio más PMCFA y dos grupos con hidróxido de calcio más CHX 2% durante dos semanas. De cada grupo con medicación uno fue obturado con cemento sellador endodóntico Grossman y el otro con Apexit Plus, mediante la técnica de compactación lateral. Los grupos control fueron obturados solo con los dos cementos anteriormente mencionados. Se cortaron las muestras en discos de 2 mm de espesor y fueron sometidas a prueba de empuje con una máquina de ensayo universal. Resultados: El valor de la media más alta lo obtuvo el grupo medicado con Ca(OH)2 más PMCFA y obturado con Apexit Plus (m 3,742 y DE 0,808), mientras que el valor más bajo lo presentó el grupo de Ca(OH)2 más PMCFA obturado con cemento Grossman (m 1,371 y DE 0,699), presentaron diferencias significativas (p < 0,001). Conclusión: La resistencia de unión a la dentina radicular se ve influenciada por la medicación intraconducto previa a la obturación endodóntica. (AU)

Objective: Compare the dentin bond strength of Grossman ́s sealer (Grossdent) and Apexit Plus sealer (IvoclarVivadent) after intra-canal medication of calcium hydroxide Ca(OH)2 associated with vehicles of camphorated parachlorophenol (CMPC) and chlorhexidine 2% (CHX). Methodology: This was an in vitro experimental study. A sample of 44 monoradicular human teeth were disinfected and divided into 4 groups of intra-canal medication (N= 9) and 2 control groups. The teeth were disinfected and root canals were instrumented using a hybrid technique. Two groups were medicated with Ca(OH)2 and CMPC and two groups with Ca(OH)2 and CHX 2% for two weeks. One group of each medication was filled with Grossman ́s sealer and the others with Apexit Plus sealer using the lateral compaction technique. The control groups were filled only with the two sealers mentioned previously. Samples were cut into 2 mm thick discs and placed on a push test with a universal testing machine. Results: The highest value of the means was obtained by the group medicated with Ca(OH)2 in association with CMPC and filled with Apexit Plus (m 3.742; SD 0.808), while the lowest value was presented by the group of Ca(OH)2 associated with CMPC, filled with Grossman ́s sealer (m 1,371; SD 0.699). Statistical differences were considered with p<0.001. Conclusion: Root dentin bond strength is influenced by intra-canal medication prior to endodontic filling. (AU)

Analgesic effect of a single preoperative dose of the antibiotic ceftriaxone in humans.

UNLABELLED: Repeated injections of the antibiotic ceftriaxone cause analgesia in rodents by upregulating the glutamate transporter, GLT-1. No evidence is available in humans. We studied the effect of a single intravenous administration of ceftriaxone in patients undergoing decompressive surgery of the median or ulnar nerves. Forty-five patients were randomized to receive saline, ceftriaxone (2 g), or cefazolin (2 g), 1 hour before surgery. Cefazolin, which is structurally related to ceftriaxone, was used as a negative control. Pain thresholds were measured 10 minutes before drug injections and then 4 to 6 hours after surgery. Ceftriaxone caused analgesia in all patients, whereas cefazolin was inactive. We also performed animal studies to examine whether a single dose of ceftriaxone was sufficient to induce analgesia. A single intraperitoneal injection of ceftriaxone (200 mg/kg), but not cefazoline (200 mg/kg), caused analgesia in mouse models of inflammatory or postsurgical pain, and upregulated GLT-1 in the spinal cord. Ceftriaxone-induced analgesia was additive to that produced by blockade of mGlu5 receptors, which are activated by extrasynaptic glutamate. These data indicate that a single dose of ceftriaxone causes analgesia in humans and mice and suggest that ceftriaxone should be used for preoperative antimicrobial prophylaxis when a fast relief of pain is desired. PERSPECTIVE: The study reports for the first time that a single preoperative dose of ceftriaxone causes analgesia in humans. A single dose of ceftriaxone could also relieve inflammatory and postsurgical pain and upregulate GLT-1 expression in mice. Ceftriaxone should be preferred to other antibiotics for antimicrobial prophylaxis to reduce postoperative pain.

Hyperalgesic activity of kisspeptin in mice.

BACKGROUND: Kisspeptin is a neuropeptide known for its role in the hypothalamic regulation of the reproductive axis. Following the recent description of kisspeptin and its 7-TM receptor, GPR54, in the dorsal root ganglia and dorsal horns of the spinal cord, we examined the role of kisspeptin in the regulation of pain sensitivity in mice. RESULTS: Immunofluorescent staining in the mouse skin showed the presence of GPR54 receptors in PGP9.5-positive sensory fibers. Intraplantar injection of kisspeptin (1 or 3 nmol/5 µl) induced a small nocifensive response in naive mice, and lowered thermal pain threshold in the hot plate test. Both intraplantar and intrathecal (0.5 or 1 nmol/3 µl) injection of kisspeptin caused hyperalgesia in the first and second phases of the formalin test, whereas the GPR54 antagonist, p234 (0.1 or 1 nmol), caused a robust analgesia. Intraplantar injection of kisspeptin combined with formalin enhanced TRPV1 phosphorylation at Ser800 at the injection site, and increased ERK1/2 phosphorylation in the ipsilateral dorsal horn as compared to naive mice and mice treated with formalin alone. CONCLUSION: These data demonstrate for the first time that kisspeptin regulates pain sensitivity in rodents and suggest that peripheral GPR54 receptors could be targeted by novel drugs in the treatment of inflammatory pain.

High number of striatal dopaminergic neurons during early postnatal development: correlation analysis with dopaminergic fibers.

Dopamine (DA) axons in the developing striatum cluster in discrete areas called "DA islands". During the third postnatal week, most DA islands are no-longer detectable and the DA innervation becomes uniform. In this study we explored the relationship between the pattern of DA innervation and the number of striatal tyrosine hydroxylase positive (TH+) cells during early postnatal development. By using dedicated stereology we found that the newborn striatum contains striatal TH+ cells, which cluster around newly sprouted DA axons. The number of these cells decreases when DA axons develop a full pattern of striatal innervation. This condition suggests a causal relationship between the amount of striatal DA innervation and the presence of striatal DA neurons. A better knowledge of the mechanisms regulating the ontogenesis of the nigrostriatal DA system may pave the way to strategies of neurorescue of the DA system.