Post-tooth extraction bacteraemia: a randomized clinical trial on the efficacy of chlorhexidine prophylaxis

Objectives: To investigate the development of post-extraction bacteraemia (PEB) after the prophylactic use of chlorhexidine (CHX). Patients and Methods: A total of 201 patients who underwent a tooth extraction were randomly distributed into four groups: 52 received no prophylaxis (CONTROL), 50 did a mouthwash with 0.2% CHX before the tooth extraction (CHX-MW), 51 did a mouthwash with 0.2% CHX and a subgingival irrigation with 1% CHX (CHX-MW/SUB_IR) and 48 did a mouthwash with 0.2% CHX and a continuous supragingival irrigation with 1% CHX (CHX-MW/SUPRA_IR). Peripheral venous blood samples were collected at baseline, 30 seconds after performing the mouthwash and the subgingival or supragingival irrigation, and at 30 seconds and 15 minutes after completion of the tooth extraction. Blood samples were analysed applying conventional microbiological cultures under aerobic and anaerobic conditions performing bacterial identification of the isolates. Results: The prevalences of PEB in the CONTROL, CHX-MW, CHX-MW/SUB_IR and CHX-MWSUPRA_IR groups were 52%, 50%, 55% and 50%, respectively, at 30 seconds and 23%, 4%, 10% and 27%, respectively, at 15 minutes. The prevalence of PEB at 15 minutes was significantly higher in the CONTROL group than in the CHX-MW group (23% versus 4%; p = 0.005). At the same time, no differences were found between CONTROL group and CHX-MW/SUB_IR or CHX-MW/SUPRA_IR groups. Streptococci (mostly viridans group streptococci) were the most frequently identified bacteria (69–79%). Conclusions: Performing a 0.2% CHX mouthwash significantly reduces the duration of PEB. Subgingival irrigation with 1% CHX didn’t increase the efficacy of the mouthwash while supragingival irrigation even decreased this efficacy, probably due to the influence of these maneuvers on the onset of bacteraemia. Clinical Relevance: These results confirm the suitability of performing a mouthwash with 0.2% CHX before tooth extractions in order to reduce the duration of PEB. This practice should perhaps be extended to all dental manipulationsThis work was supported by project PI11/01383 from Carlos III Institute of Health (General Division of Evaluation and Research Promotion, Madrid, Spain), which is integrated in National Plan of Research, Development and Innovation (PN I+D+I 2008–2011)S

Ex vivo vs. in vivo antibacterial activity of two antiseptics on oral biofilm

Aim: To compare the immediate antibacterial effect of two application methods (passive immersion and active mouthwash) of two antiseptic solutions on the in situ oral biofilm. Material and Methods: A randomized observer-masked crossover study was conducted. Fifteen healthy volunteers wore a specific intraoral device for 48 h to form a biofilm in three glass disks. One of these disks was used as a baseline; another one was immersed in a solution of 0.2% Chlorhexidine (0.2% CHX), remaining the third in the device, placed in the oral cavity, during the 0.2% CHX mouthwash application. After a 2-weeks washout period, the protocol was repeated using a solution of Essential Oils (EO). Samples were analyzed for bacterial viability with the confocal laser scanning microscope after previous staining with LIVE/DEAD® BacLight™. Results: The EO showed a better antibacterial effect compared to the 0.2% CHX after the mouthwash application (% of bacterial viability = 1.16 ± 1.00% vs. 5.08 ± 5.79%, respectively), and was more effective in all layers (p < 0.05). In the immersion, both antiseptics were significantly less effective (% of bacterial viability = 26.93 ± 13.11%, EO vs. 15.17 ± 6.14%, 0.2% CHX); in the case of EO immersion, there were no significant changes in the bacterial viability of the deepest layer in comparison with the baseline. Conclusions: The method of application conditioned the antibacterial activity of the 0.2% CHX and EO solutions on the in situ oral biofilm. The in vivo active mouthwash was more effective than the ex vivo passive immersion in both antiseptic solutions. There was more penetration of the antiseptic inside the biofilm with an active mouthwash, especially with the EO. Trial registered in clinicaltrials.gov with the number NCT02267239. URL: https://clinicaltrials.gov/ct2/show/NCT02267239.This work was supported by project PI11/01383 from Carlos III Institute of Health (General Division of Evaluation and Research Promotion, Madrid, Spain), which is integrated in National Plan of Research, Development and Innovation (PN I+D+I 2008-2011). This project was cofinanced by European Regional Development Fund (ERDF 2007-2013)S

In vitro Natural Killer Cell Immunotherapy for Medulloblastoma

How the immune system attacks medulloblastoma (MB) tumors effectively is unclear, although natural killer (NK) cells play an important role in immune defense against tumor cells. Interactions between receptors on NK cells and ligands expressed by tumor cells are critical for tumor control by immunotherapy. In this study, we analyzed tumor samples from 54 MB patients for expression of major histocompatibility complex class I-related chains A (MICA) and UL16 binding protein (ULPB-2), which are ligands for the NK group 2 member D activatory receptor (NKG2D). The percentage of MICA and ULBP-2 positive cells was higher than 25% in 68% and 6% of MB patients, respectively. A moderate-high intensity of MICA cytoplasmic staining was observed in 46% MB patients and weak ULBP-2 staining was observed in 8% MB patients. No correlation between MICA/ULBP-2 expression and patient outcome was found. We observed that HTB-186, a MB cell line, was moderately resistant to NK cell cytotoxicity in vitro. Blocking MICA/ULBP-2 on HTB-186, and NKG2D receptor on NK cells increased resistance to NK cell lysis in vitro. However, HLA class I blocking on HTB-186 and overnight incubation with IL-15 stimulated NK cells efficiently killed tumor cells in vitro. We conclude that although NKG2D/MICA-ULBP-2 interactions have a role in NK cell cytotoxicity against MB, high expression of HLA class I can protect MB from NK cell cytotoxicity. Even so, our in vitro data indicate that if NK cells are appropriately stimulated, they may have the potential to target MB in vivo

Tumours in the pineal region in the paediatric age: Reports of 23 cases and a review of the literature

Introducción. Los tumores de la región pineal se localizan en una encrucijada de estructuras neurovasculares de difícil acceso quirúrgico y limitadas posibilidades de resección; por ello, el manejo de estas lesiones habitualmente requiere la asociación de tratamiento adyuvante radioterápico y/o quimioterápico. Pacientes y métodos. Análisis retrospectivo de las características epidemiológicas, clínicas, neurorradiológicas y anatomopatológicas de 23 pacientes con tumores de la región pineal tratados entre los años 1997 y 2010 en el Hospital Infantil Niño Jesús. Se discuten los factores implicados en el pronóstico de esta cohorte tras el tratamiento quirúrgico o adyuvante. Resultados. El estudio incluyó 6 niñas y 17 niños con edades comprendidas entre los 4 meses y 18 años. El 95% de los pacientes comenzó con signos de hidrocefalia aguda o subaguda, que precisaron la implantación de una derivación ventriculoperitoneal (82%). Se obtuvo una muestra histológica tumoral en todos los casos. Cinco pacientes fueron biopsiados y 18 fueron intervenidos mediante craneotomía. El germinoma (ocho casos) y el teratoma maduro (un caso) fueron los tumores con mayor supervivencia; los tumores no germinomatosos (tres casos), del parénquima pineal (cuatro casos) y gliomas (cinco casos) presentaron mayor tasa de recidiva y un peor pronóstico. Conclusión. El estudio de marcadores tumorales permite orientar el diagnóstico de determinados tumores de la región pineal. Actualmente, se recomienda realizar una toma histológica tumoral para establecer un diagnóstico preciso y un tratamiento oncológico específicoIntroduction. Tumours in the pineal region are located at a meeting point of several neurovascular structures that are difficult to reach surgically and for which the possibility of resection is limited; as a result the management of these lesions usually requires associated adjunctive treatment with radiotherapy and/or chemotherapy. Patients and methods. This study is a retrospective analysis of the epidemiological, clinical, neuroimaging and pathological characteristics of 23 patients with tumours in the pineal region who were treated between the years 1997 and 2010 in the Hospital Infantil Niño Jesús. The factors involved in the prognosis of this cohort following surgical or adjunctive treatment are also discussed. Results. Subjects included in the study were 6 girls and 17 boys with ages ranging from 4 months to 18 years. It was found that the initial symptoms in 95% of the patients were signs of acute or subacute hydrocephalus, which required the placement of a ventriculoperitoneal shunt (82%). A histological sample of the tumour tissue was collected in all cases. Biopsy samples were taken in the case of five patients and 18 underwent surgery involving a craniotomy. Germinoma (eight cases) and mature teratoma (one case) were the tumours with the longest survival times; non-germinomatous tumours (three cases), those of the pineal parenchyma (four cases) and gliomas (five cases) presented the highest rates of recurrence and a poorer prognosis. Conclusions. The study of tumour markers can be used to guide the diagnosis of certain tumours of the pineal region. At present, the recommended procedure involves taking a histological sample of the tumour in order to establish an accurate diagnosis and a specific oncological treatmen

Factors Explaining Language Performance After Training in Elders With and Without Subjective Cognitive Decline

The present study explores if cognitive reserve, executive functions, and working memory capacity are predictive of performance in the language domain (specifically in sentence comprehension and naming) after a cognitive training intervention. Sixty-six Spanish older adults voluntarily participated in the study, classified either as older adults with subjective cognitive decline according to Jessen et al.’s (2014) criteria (n = 35; 70.94 ± 4.16 years old) or cognitively intact (n = 31; 71.34 ± 4.96 years old). Written sentence comprehension and visual confrontation naming were assessed both immediately after recruitment (at the baseline), and then 6 months later, once each participant had completed his/her cognitive training (a well-known program in Spain, called UMAM; English translation: Madrid City Council Memory Unit Program). Cognitive reserve, executive functions (cognitive flexibility and controlled interference efficiency), and working memory capacity were measured for all participants at the baseline. Results pointed out that the subjective cognitive decline group presented greater benefits in the language domain than cognitively intact participants. We also observed that lower executive functioning and working memory capacity at the baseline predicted larger benefits in language performance after training, but only in the group of cognitively intact older adults. However, selected predictors hardly explained subjective cognitive decline participants’ results in language performance after training

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Contribution of Altered Endocannabinoid System to Overactive mTORC1 Signaling in Focal Cortical Dysplasia

Alterations of the PI3K/Akt/mammalian target of rapamycin complex 1 (mTORC1) signaling pathway are causally involved in a subset of malformations of cortical development (MCDs) ranging from focal cortical dysplasia (FCD) to hemimegalencephaly and megalencephaly. These MCDs represent a frequent cause of refractory pediatric epilepsy. The endocannabinoid system -especially cannabinoid CB1 receptor- exerts a neurodevelopmental regulatory role at least in part via activation of mTORC1 signaling. Therefore, we sought to characterize the possible contribution of endocannabinoid system signaling to FCD. Confocal microscopy characterization of the CB1 receptor expression and mTORC1 activation was conducted in FCD Type II resection samples. FCD samples were subjected to single nucleotide polymorphism screening for endocannabinoid system elements, as well as CB1 receptor gene sequencing. Cannabinoid CB1 receptor levels were increased in FCD with overactive mTORC1 signaling. CB1 receptors were enriched in phospho-S6-positive cells including balloon cells (BCs) that co-express aberrant markers of undifferentiated cells and dysplastic neurons. Pharmacological regulation of CB1 receptors and the mTORC1 pathway was performed in fresh FCD-derived organotypic cultures. HU-210-evoked activation of CB1 receptors was unable to further activate mTORC1 signaling, whereas CB1 receptor blockade with rimonabant attenuated mTORC1 overactivation. Alterations of the endocannabinoid system may thus contribute to FCD pathological features, and blockade of cannabinoid signaling might be a new therapeutic intervention in FCD