Oligodeoxynucleotides containing unmethylated cytosine-guanine motifs are effective immunostimulants against pneumococcal meningitis in the immunocompetent and neutropenic host.

BACKGROUND: Bacterial meningitis is a fatal disease with a mortality up to 30% and neurological sequelae in one fourth of survivors. Available vaccines do not fully protect against this lethal disease. Here, we report the protective effect of synthetic oligodeoxynucleotides containing unmethylated cytosine-guanine motifs (CpG ODN) against the most frequent form of bacterial meningitis caused by Streptococcus pneumoniae. METHODS: Three days prior to the induction of meningitis by intracerebral injection of S. pneumoniae D39, wild-type and Toll-like receptor (TLR9)-/- mice received an intraperitoneal injection of 100 µg CpG ODN or vehicle. To render mice neutropenic, anti-Ly-6G monoclonal antibody was daily administrated starting 4 days before infection with a total of 7 injections. Kaplan-Meier survival analyses and bacteriological studies, in which mice were sacrificed 24 h and 36 h after infection, were performed. RESULTS: Pre-treatment with 100 µg CpG ODN prolonged survival of immunocompetent and neutropenic wild-type mice but not of TLR9-/- mice. There was a trend towards lower mortality in CpG ODN-treated immunocompetent and neutropenic wild-type mice. CpG ODN caused an increase of IL-12/IL-23p40 levels in the spleen and serum in uninfected animals. The effects of CpG ODN on bacterial concentrations and development of clinical symptoms were associated with an increased number of microglia in the CNS during the early phase of infection. Elevated concentrations of IL-12/IL-23p40 and MIP-1α correlated with lower bacterial concentrations in the blood and spleen during infection. CONCLUSIONS: Pre-conditioning with CpG ODN strengthened the resistance of neutropenic and immunocompetent mice against S. pneumoniae meningitis in the presence of TLR9. Administration of CpG ODN decreased bacterial burden in the cerebellum and reduced the degree of bacteremia. Systemic administration of CpG ODN may help to prevent or slow the progression to sepsis of bacterial CNS infections in healthy and immunocompromised individuals even after direct inoculation of bacteria into the intracranial compartments, which can occur after sinusitis, mastoiditis, open head trauma, and surgery, including placement of an external ventricular drain.

Concomitant multipotent and unipotent dental pulp progenitors and their respective contribution to mineralised tissue formation.

Upon in vitro induction or in vivo implantation, the stem cells of the dental pulp display hallmarks of odontoblastic, osteogenic, adipogenic or neuronal cells. However, whether these phenotypes result from genuine multipotent cells or from coexistence of distinct progenitors is still an open question. Furthermore, determining whether a single cell-derived progenitor is capable of undergoing a differentiation cascade leading to tissue repair in situ is important for the development of cell therapy strategies. Three clonal pulp precursor cell lines (A4, C5, H8), established from embryonic ED18 first molars of mouse transgenic for a recombinant plasmid adeno-SV40, were induced to differentiate towards the odonto/osteogenic, chondrogenic or adipogenic programme. Expression of phenotypic markers of each lineage was evaluated by RT-PCR, histochemistry or immunocytochemistry. The clones were implanted into mandibular incisors or calvaria of adult mice. The A4 clone was capable of being recruited towards at least 3 mesodermal lineages in vitro and of contributing to dentin-like or bone formation, in vivo, thus behaving as a multipotent cell. In contrast, the C5 and H8 clones displayed a more restricted potential. Flow cytometric analysis revealed that isolated monopotent and multipotent clones could be distinguished by a differential expression of CD90. Altogether, isolation of these clonal lines allowed demonstrating the coexistence of multipotential and restricted-lineage progenitors in the mouse pulp. These cells may further permit unravelling specificities of the different types of pulp progenitors, hence facilitating the development of cell-based therapies of the dental pulp or other cranio-facial tissues.

Efficacy of fosfomycin and its combination with linezolid, vancomycin and imipenem in an experimental peritonitis model caused by a Staphylococcus aureus strain with reduced susceptibility to vancomycin.

The objective of this study was to evaluate the in vitro and in vivo efficacies of therapies including fosfomycin against clinical Staphylococcus aureus isolates with reduced susceptibility to vancomycin (hGISA). Time-kill curves were performed over 24 h. Peritonitis in C57BL/6 mice was induced by intraperitoneal inoculation of 10(8) CFU/ml. Four hours later (0 h), therapy was started and the treatment groups were: control (not treated), fosfomycin (100 mg/kg/5 h), vancomycin (60 mg/kg/5 h), imipenem (30 mg/kg/5 h), fosfomycin plus linezolid, fosfomycin plus vancomycin and fosfomycin plus imipenem, receiving subcutaneous therapy over 25 h. Bacterial counts in peritoneal fluid, bacteraemia and mortality rates were determined. In vitro, fosfomycin showed a synergistic effect when combined with the other antimicrobials tested. In the animal model, fosfomycin combinations were effective and significantly reduced the bacteraemia rates achieved in the control, imipenem and vancomycin groups (p < 0.05). The best combination in vivo was fosfomycin plus imipenem. Also, fosfomycin plus linezolid was significantly better than vancomycin alone, reducing the bacterial concentration in the peritoneal fluid. In conclusion, in vitro and in vivo, fosfomycin in combination with linezolid, vancomycin or imipenem exerted a good activity. Fosfomycin plus imipenem was the most active combination, decreasing 3 log CFU/ml, and appears to be a promising combination for clinical practice.

In vitro and in vivo activities of linezolid alone and combined with vancomycin and imipenem against Staphylococcus aureus with reduced susceptibility to glycopeptides.

The objective of this study was to evaluate the in vitro and in vivo efficacies of linezolid (35 mg/kg/5 h), vancomycin (60 mg/kg/5 h), imipenem (30 mg/kg/5 h), linezolid+imipenem, linezolid+vancomycin and vancomycin+imipenem against two clinical Staphylococcus aureus isolates with reduced susceptibility to glycopeptides using time-kill curves and the murine peritonitis model. Time-kill curves were performed over 24 h. For the murine peritonitis model, peritonitis was induced by the intraperitoneal inoculation of 10(8) CFU/ml of each bacterial strain. Four hours later (0 h), the mice were randomly assigned to a control group or to therapeutic groups receiving subcutaneous treatment for 25 h. Bacterial counts in peritoneal fluid, bacteraemia and mortality rates were determined. The time-kill curves showed that the addition of linezolid to imipenem yielded synergistic results after 24 h. The addition of linezolid decreased vancomycin activity. In the animal model, vancomycin and linezolid monotherapies produced comparable bacterial decreases in mice infected with each strain but linezolid achieved higher rates of blood sterilisation. Linezolid tested either in monotherapy or in combination showed similar efficacy against both strains in terms of bacterial killing, number of negative blood cultures and survival. Linezolid and vancomycin were moderately bactericidal and similar in efficacy against glycopeptide-intermediate or -resistant S. aureus. Linezolid combinations, as effective as linezolid tested alone, could be considered as alternative options for the treatment of glycopeptide-intermediate S. aureus (GISA) infections.

Evaluation of meropenem alone and combined with rifampin in the guinea pig model of pneumococcal meningitis.

Meropenem is a broad-spectrum carbapenem antibiotic that is highly active against the pathogens causing meningitis. The aims of this study was to determine the efficacies of meropenem alone and combined with rifampin against two Streptococcus pneumoniae strains with different susceptibility to beta-lactams using the guinea pig meningitis model and compare them with the standard ceftriaxone plus vancomycin therapy. All treatments except rifampin were bactericidal from 6 h. The addition of rifampin did not improve the activity of meropenem alone. Our results provide good evidence of the efficacy of meropenem in the treatment of penicillin- and cephalosporin-susceptible and -resistant pneumococcal meningitis similar to that of ceftriaxone plus vancomycin, suggesting that meropenem might be a good option in the management of this infection.

Sclerostin Deficiency Promotes Reparative Dentinogenesis.

In humans, the SOST gene encodes sclerostin, an inhibitor of bone growth and remodeling, which also negatively regulates the bone repair process. Sclerostin has also been implicated in tooth formation, but its potential role in pulp healing remains unknown. The aim of this study was to explore the role of sclerostin in reparative dentinogenesis using Sost knockout mice ( Sost-/-). The pulps of the first maxillary molars were mechanically exposed in 3-mo-old Sost-/- and wild-type (WT) mice ( n = 14 mice per group), capped with mineral trioxide aggregate cement, and the cavities were filled with a bonded composite resin. Reparative dentinogenesis was dynamically followed up by micro-computed tomography and characterized by histological analyses. Presurgical analysis revealed a significantly lower pulp volume in Sost-/- mice compared with WT. At 30 and 49 d postsurgery, a large-forming reparative mineralized bridge, associated with osteopontin-positive mineralization foci, was observed in the Sost-/- pulps, whereas a much smaller bridge was detected in WT. At the longer time points, the bridge, which was associated with dentin sialoprotein-positive cells, had expanded in both groups but remained significantly larger in Sost-/- pulps. Sclerostin expression in the healing WT pulps was detected in the cells neighboring the forming dentin bridge. In vitro, mineralization induced by Sost-/- dental pulp cells (DPCs) was also dramatically enhanced when compared with WT DPCs. These observations were associated with an increased Sost expression in WT cells. Taken together, our data show that sclerostin deficiency hastened reparative dentinogenesis after pulp injury, suggesting that the inhibition of sclerostin may constitute a promising therapeutic strategy for improving the healing of damaged pulps.

Experimental study of clinafloxacin alone and in combination in the treatment of ciprofloxacin-susceptible and -resistant pneumococcal meningitis.

The increasing incidence of ciprofloxacin resistance in Streptococcus pneumoniae may limit the efficacy of the new quinolones in difficult-to-treat infections such as meningitis. The aim of the present study was to determine the efficacy of clinafloxacin alone and in combination with teicoplanin and rifampin in the therapy of ciprofloxacin-susceptible and ciprofloxacin-resistant pneumococcal meningitis in rabbits. When used against a penicillin-resistant ciprofloxacin-susceptible strain (Clinafloxacin MIC 0.12 microg/ml), clinafloxacin at a dose of 20 mg/kg per day b.i.d. decreased bacterial concentration by -5.10 log cfu/ml at 24 hr. Combinations did not improve activity. The same clinafloxacin schedule against a penicillin- and ciprofloxacin-resistant strain (Clinafloxacin MIC 0.5 microg/ml) was totally ineffective. Our data suggest that a moderate decrease in quinolone susceptibility, as indicated by the detection of any degree of ciprofloxacin resistance, may render these antibiotics unsuitable for the management of pneumococcal meningitis.

Automatic segmentation of breast MR images through a Markov random field statistical model.

An algorithm dedicated to automatic segmentation of breast magnetic resonance images is presented in this paper. Our approach is based on a pipeline that includes a denoising step and statistical segmentation. The noise removal preprocessing relies on an anisotropic diffusion scheme, whereas the statistical segmentation is conducted through a Markov random field model. The continuous updating of all parameters governing the diffusion process enables automatic denoising, and the partial volume effect is also addressed during the labeling step. To assess the relevance, the Jaccard similarity coefficient was computed. Experiments were conducted on synthetic data and breast magnetic resonance images extracted from a high-risk population. The relevance of the approach for the dataset is highlighted, and we demonstrate accuracy superior to that of traditional clustering algorithms. The results emphasize the benefits of both denoising guided by input data and the inclusion of spatial dependency through a Markov random field. For example, the Jaccard coefficient for the clinical data was increased by 114%, 109%, and 140% with respect to a K-means algorithm and, respectively, for the adipose, glandular and muscle and skin components. Moreover, the agreement between the manual segmentations provided by an experienced radiologist and the automatic segmentations performed with this algorithm was good, with Jaccard coefficients equal to 0.769, 0.756, and 0.694 for the above-mentioned classes.

ES cells-derived ectomesenchymal cells for tooth engineering.

Recent progresses in stem cell biology and tissue engineering allow considering the possible development of new therapies for compensating the dental tissue losses associated with traumas, pathologies or ageing. The possibility of generating a tooth by mimicking development through reassociations between dental epithelial cells and ectomesenchymal cells derived from the neural crest (NC) has been demonstrated in the mouse. In the search of cell sources to be used for a human transfer, pluripotent stem cells could represent a good alternative. Our study thus focuses on obtaining, ectomesenchymal cells from pluripotent ES cells, capable of promoting tooth histomorphogenesis, when reassociated with a competent dental epithelium. To this end, two ES differentiation protocols, using cyclopamine or a combination of FGF2 and BMP4, have been developed and tested for their capacity to generate such cells. The differentiated ES cells were characterized by quantitative RT-PCR. Both protocols led the cells to acquire in 10 days a mesenchymal-like cell morphology. Rapidly after induction, the cells loose their expression of pluripotent genes while sequentially activating typical NC specifiers. However, the kinetics of gene activation differed between the 2 protocols. Interestingly, Twist, a gene whose expression in the NC is associated with a commitment towards an ectomesenchymal fate, is only activated under the influence of FGF2 and BMP4. Reassociation experiments with a competent epithelium will allow testing the odontogenic potential of the differentiated ES cells. These experiments performed in the mouse system should allow defining a strategy for obtaining odontogenic competent human cells.

[Severe pre-eclampsia. An evidence-based practice proposal]. / Preeclampsia grave. Propuesta de actuación basada en la evidencia.

OBJECTIVES: There are several treatment proposals for the obstetric patient with pre-eclampsia, but there is limited evidence on the adequacy of standard treatment. International healthcare organisations recommend that hospitals or anaesthesia departments have written guidelines, protocols or recommendations for dealing with common or severe situations. We propose evidence-based recommendations for the treatment of pre-eclampsia. MATERIAL AND METHODS: A literature review was performed using several sources, bibliography databases, recommendations made by specialist societies, and reviews. Four anaesthesiologists reviewed the references selected, in order to design clinical questions (these were obtained from recent pre-eclampsia review articles). Consensus of at least 3 out of 4 experts was required. The Oxford criteria for evidence were chosen to classify the scientific articles, and the Jadad score was applied to the final articles selected. RESULTS: A total of 50 clinical questions were designed and answered. These were classified into: general questions, influence of the type of delivery, pre-anaesthesia evaluation, peripartum treatment (including analgesia and anaesthesia), eclampsia, post-delivery period, and intensive care and transport. Most of the responses showed low scientific evidence. CONCLUSIONS: Evidence-based recommendations for severe pre-eclampsia treatment were provided with special emphasis on the anaesthesiologist point of view.

The retrospective binning method improves the consistency of phase binning in respiratory-gated PET/CT.

This study assesses the accuracy of prospective phase-gated PET/CT data binning and presents a retrospective data binning method that improves image quality and consistency. Respiratory signals from 17 patients who underwent 4D PET/CT were analysed to evaluate the reproducibility of temporal triggers used for the standard phase-based gating method. Breathing signals were reprocessed to implement retrospective PET data binning. The mean and standard deviation of time lags between automatic triggers provided by the Real-time Position Management (RPM, Varian) gating device and inhalation peaks derived from respiratory curves were computed for each patient. The total number of respiratory cycles available for 4D PET/CT according to the binning mode (prospective versus retrospective) was compared. The maximum standardized uptake value (SUV(max)), biological tumour volume (BTV) and tumour trajectory measures were determined from the PET/CT images of five patients. Compared to retrospective binning (RB), prospective gating approach led to (i) a significant loss in breathing cycles (15%) and (ii) the inconsistency of data binning due to temporal dispersion of triggers (average 396 ms). Consequently, tumour characterization could be impacted. In retrospective mode, SUV(max) was up to 27% higher, where no significant difference appeared in BTV. In addition, prospective mode gave an inconsistent spatial location of the tumour throughout the bins. Improved consistency with breathing patterns and greater motion amplitude of the tumour centroid were observed with retrospective mode. The detection of the tumour motion and trajectory was improved also for small temporal dispersion of triggers. This study shows that the binning mode could have a significant impact on 4D PET images. The consistency of triggers with breathing signals should be checked before clinical use of gated PET/CT images, and our RB method improves 4D PET/CT image quantification.

Experimental study of meropenem in the therapy of cephalosporin-susceptible and -resistant pneumococcal meningitis.

Meropenem is a carbapenem antibiotic that is highly active against the pathogens causing meningitis. Results with meropenem in the experimental rabbit model of penumococcal meningitis have been controversial, and the possible role of renal dehydropeptidase I in meropenem efficacy has been suggested. The aim of this study was to determine the efficacy of meropenem in two meningitis models and the possible influence of the animal model over results. Two strains of Streptococcus pneumoniae with different susceptibility to beta-lactams have been used in a guinea pig model and the classical rabbit meningitis model. Meropenem was bactericidal at 6 h in the guinea pig model against both strains with a reduction of >4 log ufc/ml. In the rabbit model it was bactericidal at 6 h against the susceptible strain, but against the resistant 3/8 therapeutical failures were recorded at 6 h, being bactericidal at 24 h. In conclusion, meropenem has shown bactericidal activity in both experimental models. This work emphasises the importance of an adequate election of the animal model for the appropriate development of studies of antimicrobial efficacy. We believe that guinea pig should be considered the best choice among laboratory animal species when assessing meropenem efficacy.

Experimental study of teicoplanin, alone and in combination, in the therapy of cephalosporin-resistant pneumococcal meningitis.

OBJECTIVES: The aim of the study was to determine the efficacy of teicoplanin, alone and in combination with ceftriaxone, in a rabbit model of cephalosporin-resistant pneumococcal meningitis, and to assess the effect of concomitant therapy with dexamethasone. METHODS: In vitro killing curves of teicoplanin, with and without ceftriaxone, were performed. Groups of eight animals per treatment were inoculated with a cephalosporin-resistant pneumococcal strain (penicillin MIC, 4 mg/L; ceftriaxone MIC, 2 mg/L; teicoplanin MIC, 0.03 mg/L) and treated over a 26 h period. Teicoplanin was administered at a dose of 15 mg/kg, alone and in combination with ceftriaxone at 100 mg/kg with or without dexamethasone at 0.25 mg/kg. CSF samples were collected at different time-points, and bacterial titres, white blood cell counts, lactate and protein concentrations and bacteriostatic/bactericidal titres were determined. Blood and CSF teicoplanin pharmacokinetic and pharmacodynamic parameters were determined. RESULTS: Teicoplanin alone promoted a decrease in bacterial counts at 6 h of -2.66 log cfu/mL and was bactericidal at 24 h, without therapeutic failures. Similar good results were obtained when dexamethasone was used simultaneously, in spite of the penetration of teicoplanin into the CSF being significantly reduced, from 2.31% to 0.71%. Teicoplanin and ceftriaxone combinations were synergic in vitro, but not in the meningitis model. CONCLUSIONS: Teicoplanin alone was very effective in this model of cephalosporin-resistant pneumococcal meningitis. The use of concomitant dexamethasone resulted in lower CSF teicoplanin levels, but not in therapeutic failures. The combination of teicoplanin plus ceftriaxone and dexamethasone might be a good alternative for the empirical therapy of pneumococcal meningitis. Additional data should confirm our experiments, in advance of clinical trials to assess efficacy in humans.

Preeclampsia grave. Propuesta de actuación basada en la evidencia / Severe pre-eclampsia. An evidence-based practice proposal

Objetivos. Aunque hay numerosas pautas de tratamiento de la preeclampsia en la paciente obstétrica, hay escasa evidencia acerca de lo adecuado del tratamiento estándar. Por otra parte, organismos sanitarios internacionales recomiendan que haya disponibles recomendaciones, protocolos o guías escritas para la atención de situaciones frecuentes o graves por parte de hospitales o servicios de anestesia. Nuestro objetivo fue elaborar recomendaciones basadas en la evidencia sobre el abordaje terapéutico de la paciente con preeclampsia grave. Material y métodos. Se realizó una revisión de la bibliografía obtenida de diversas fuentes, bases de datos, recomendaciones de sociedades y revisiones. Se llevó a cabo por 4 anestesiólogos expertos que plantearon preguntas clínicas (extraídas de la lectura de revisiones recientes sobre preeclampsia). Para la selección final se requirió consenso de al menos 3 de los 4 expertos. Se siguieron los criterios de asignación de evidencia de Oxford y se aplicó la escala de Jadad a los estudios seleccionados. Resultados. Se eligieron 50 preguntas clínicas que fueron respondidas. Se clasificaron en: medidas generales, influencia de la forma de parto, evaluación preanestésica, tratamiento periparto (incluyendo la analgesia y anestesia), eclampsia, posparto y tratamiento intensivo y traslado. La mayoría de las respuestas presentan una evidencia científica baja que las avale. Conclusiones. Se proponen unas recomendaciones basadas en la evidencia para el tratamiento de la preeclampsia grave, especialmente enfocadas a los anestesiólogos(AU)

Objectives. There are several treatment proposals for the obstetric patient with pre-eclampsia, but there is limited evidence on the adequacy of standard treatment. International healthcare organisations recommend that hospitals or anaesthesia departments have written guidelines, protocols or recommendations for dealing with common or severe situations. We propose evidence-based recommendations for the treatment of pre-eclampsia. Material and methods. A literature review was performed using several sources, bibliography databases, recommendations made by specialist societies, and reviews. Four anaesthesiologists reviewed the references selected, in order to design clinical questions (these were obtained from recent pre-eclampsia review articles). Consensus of at least 3 out of 4 experts was required. The Oxford criteria for evidence were chosen to classify the scientific articles, and the Jadad score was applied to the final articles selected. Results. A total of 50 clinical questions were designed and answered. These were classified into: general questions, influence of the type of delivery, pre-anaesthesia evaluation, peripartum treatment (including analgesia and anaesthesia), eclampsia, post-delivery period, and intensive care and transport. Most of the responses showed low scientific evidence. Conclusions. Evidence-based recommendations for severe pre-eclampsia treatment were provided with special emphasis on the anaesthesiologist point of view(AU)