Black TiO2 nanotubes: Efficient electrodes for triggering electric field-induced stimulation of stem cell growth.

TiO2 nanostructures represent a key platform for biomedical applications, due to the combination of biocompatibility and high surface area. Especially TiO2 nanotube layers have been widely investigated due to controllable nanotopographic effects as well as for electrodes in electrostimulation experiments. In the present work we produce Ar/H2-reduced 'black' TiO2 nanotube arrays with a strongly enhanced electrical conductivity and explore their interaction with mesenchymal stem cells when used as electrodes to apply electric fields (EF) across the cells. While we observe no significant change in cell adhesion and their focal contact formation on these high conductivity nanotubes, we do observe a rapid stem cell response when EF is engaged using the 'black' TiO2 nanotube arrays as electrodes. Compared to as-formed nanotube arrays, a faster stem cell growth was observed and a lower EF intensity caused an intracellular calcium level elevation. Our results indicate that the increased conductivity in TiO2 nanotubes significantly enhances the early stem cell response to minimal electric field stimuli. STATEMENT OF SIGNIFICANCE: The use of TiO2 nanostructures in biomedical applications is widely investigated, especially considering the nanostructured surface influence on the biomaterial-cell interactions. We have previously shown that an applied electric field (EF) on stem cells grown on TiO2 nanotubes leads to synergistic osteogenic stimulation in the absence of biochemical bone-inducing supplements. Here we report that black (i.e. highly conductive nanotubes obtained by reduction treatments) TiO2 nanotubes enable short-time EF effects on stem cells: we observe a faster stem cell growth and a significantly enhanced early stem cell response to minimal EF stimuli. The application of such nanostructures under electric field is promising for therapeutic interventions for bone regeneration and tissue engineering approaches.

Molecular drug susceptibility testing in the Netherlands: performance of the MTBDRplus and MTBDRsl assays.

BACKGROUND: The performance of molecular drug susceptibility testing in countries with a low prevalence of drug resistance, such as the Netherlands, has not been adequately studied. OBJECTIVE: To evaluate the diagnostic accuracy of the GenoType(®) MTBDRplus and MTBDRsl assays to detect resistance to first- and second-line anti-tuberculosis drugs in the context of a nationwide screening programme in the Netherlands. RESULTS: The MTBDRplus assay had a sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of 100%, 99%, 80% and 100% for detecting rifampicin resistance. The sensitivity, specificity, PPV and NPV of either a katG or inhA mutation for detecting isoniazid resistance were 88%, 100%, 100% and 99%. The MTBDRsl assay had a sensitivity, specificity, PPV and NPV of 100%, 99%, 83%, and 100% for detecting moxifloxacin resistance; 62%, 71%, 58% and 74%, respectively, for detecting ethambutol resistance; 86%, 99%, 86% and 99% for detecting amikacin resistance; and 50%, 96%, 71% and 91% for detecting capreomycin resistance. CONCLUSION: The MTBDRplus and MTBDRsl assays may aid in decision making in tuberculosis treatment in low-level drug resistance settings and should preferably be used to exclude resistance.

A systematic review on the influence of trial quality on the effect of garlic on blood pressure.

BACKGROUND: Garlic is a widely used herbal product for hypertension. Previous meta-analyses on the effect of garlic on blood pressure (BP) have been contradictory however. We hypothesised that methodological deficiencies may have contributed to this disagreement. We therefore evaluated whether trials reporting on the effect of garlic on BP had sufficient methodological qualities and a proper description of BP determination. METHODS: MEDLINE , EMBASE, AMED, the COCHRANE library, IBIDS and CINA HL were systematically searched for trials reporting on the effect of garlic on BP. Both the methodological quality and the quality of blood pressure measurement were appraised using predefined quality scores. RESULTS: 32 Studies were identified. Of these studies, 13 were included previously by other meta-analyses. The methodological quality of the studies was poor. Only four trials had adequate allocation concealment, no single trial reported an intention-to-treat analysis and blinding of the evaluators was done in three trials only. Moreover, half of the studies did not report any data on BP measurement. No trials reported on the arm level. Body position was described most often. All trials fulfilling a predefined cutoff point were conducted in normotensive subjects. CONCLUSION: The effect of garlic on blood pressure cannot be ascertained. Previous meta-analyses have been based on trials with inadequate study designs, methodological deficiencies and with too little information about blood pressure measurement. In our view, use of garlic cannot be recommended as antihypertensive advice for hypertensive patients in daily practice.

CT-simulator based brachytherapy planner: seed localization and incorporation of biological considerations.

Radiation dose prescription, interpretation, and planning can be problematic for brachytherapy due to high spatial heterogeneity, varying and various dose rates, absence of superimposed calculated isodose distributions onto affected tissues, and lack of dose volume histograms. A new treatment planner has been developed to reduce these limitations in brachytherapy planning. The PC-based planning system uses a CT-simulator to sequentially scan the patient to generate orthogonal images (to localize seed positions) and subsequently axially scan the patient. This sequential scanning procedure avoids using multiple independent patient scans, templates, external frames, or fiducial markers to register the reconstructed seed positions with patient contours. Dose is computed after assigning activity to (low dose rate) Ir192, linear Cs137, or I125 seeds or dwell times (high dose rate) to the Ir192 source. The planar isodose distribution is superimposed onto axial, coronal, or sagittal views of the tissues following image reconstruction. The treatment plan computes (1) direct and cumulative volume dose histograms for individual tissues, (2) the average, standard deviation, and coefficient of skewness of the dose distribution within individual tissues, (3) an average (over all tissue pixels) survival probability (S) and average survival dose DASD for a given radiation treatment, (4) normal tissue complication probability (NTCP) delivered to a given tissue. All four computed quantities account for dose heterogeneity. These estimates of the biological response to radiation from laboratory-based studies may help guide the evaluation of the prescribed low- or high-dose rate therapy in retrospective and prospective clinical studies at a number of treatment sites.

The laryngeal mask airway for awake diagnostic bronchoscopy. A retrospective study of 200 consecutive patients.

The laryngeal mask airway (LMA) provides a view of the larynx and moving vocal cords without loss of airway control and can be used in flexible fibreoptic bronchoscopy for both anaesthetized and awake patients. In this retrospective review of 200 consecutive patients over a 30 month period, bronchoscopy was successful via the LMA in all but one patient using a technique of topical anaesthesia and sedation. The LMA directs the fibrescope to the glottis, allows respiratory function to be monitored and oxygen to be given. Complication rates were similar to those reported for transnasal awake bronchoscopy. Insertion of the LMA in the awake fasted patient is safe and easily achieved.