Survival Differences of Patients with Resected Extraskeletal Osteosarcoma Receiving Two Different (Neo)Adjuvant Chemotherapy Regimens: A Systematic Review and Meta-analysis

AIMS

Extraskeletal osteosarcoma (ESOS) is a malignant tumour developing in soft tissues, characterised by the production of osteoid or bone matrix by tumour cells. The standard treatment for localised ESOS is wide resection. Radiotherapy and chemotherapy are usually incorporated into the management of patients. Two types of chemotherapy regimen are mostly used: an osteosarcoma-type chemotherapy, based on cisplatin, and a soft-tissue sarcoma (STS)-type chemotherapy, using the combination of doxorubicin and ifosfamide. To investigate the difference in survival between these two chemotherapy regimens, a systematic review of studies reporting the 5-year disease-free survival (DFS) rates among patients with ESOS submitted to surgery and who received (neo)adjuvant chemotherapy with osteosarcoma-type or STS-type chemotherapy was carried out.

MATERIALS AND METHODS

Of the 401 articles identified by systematically searching the PubMed, Embase and Cochrane Central Register of Controlled Trials databases, six retrospective studies were included in the final analysis. In total, 319 patients with localised/resected ESOS were included in the study.

RESULTS

Our meta-analysis showed a benefit in 5-year DFS favouring the use of osteosarcoma-type chemotherapy (relative risk = 1.32, 95% confidence interval 1.03-1.69; P = 0.54); I2 heterogeneity was 0%. The 5-year DFS rate was 56.3% (95% confidence interval 48.3-64.3) with osteosarcoma-type chemotherapy and 45.2% (95% confidence interval 34.5-55.9) with STS-type chemotherapy, with I2 heterogeneity of 27% and 0%, respectively.

CONCLUSIONS

Our analysis suggests that there may be a difference regarding the type of (neo)adjuvant chemotherapy regimen used in the treatment of patients with resected ESOS in favour of osteosarcoma-type chemotherapy. Future studies evaluating the role of this treatment modality in this scenario need to consider the type of chemotherapy regimen when comparing with an arm of surgery with/without radiotherapy alone.

Development of secretome-based strategies to improve cell culture protocols in tissue engineering

Advances in skin tissue engineering have promoted the development of artificial skin substitutes to treat large burns and other major skin loss conditions. However, one of the main drawbacks to bioengineered skin is the need to obtain a large amount of viable epithelial cells in short periods of time, making the skin biofabrication process challenging and slow. Enhancing skin epithelial cell cultures by using mesenchymal stem cells secretome can favor the scalability of manufacturing processes for bioengineered skin. The effects of three different types of secretome derived from human mesenchymal stem cells, e.g. hADSC-s (adipose cells), hDPSC-s (dental pulp) and hWJSC-s (umbilical cord), were evaluated on cultured skin epithelial cells during 24, 48, 72 and 120 h to determine the potential of this product to enhance cell proliferation and improve biofabrication strategies for tissue engineering. Then, secretomes were applied in vivo in preliminary analyses carried out on Wistar rats. Results showed that the use of secretomes derived from mesenchymal stem cells enhanced currently available cell culture protocols. Secretome was associated with increased viability, proliferation and migration of human skin epithelial cells, with hDPSC-s and hWJSC-s yielding greater inductive effects than hADSC-s. Animals treated with hWJSC-s and especially, hDPSC-s tended to show enhanced wound healing in vivo with no detectable side effects. Mesenchymal stem cells derived secretomes could be considered as a promising approach to cell-free therapy able to improve skin wound healing and regeneration.

Irrigation and phosphorous fertilization management to minimize rice grain arsenic content

This research sought to minimize inorganic arsenic levels in polished rice grain by using different irrigation and phosphorous fertilization practices while also maintaining crop yield and water productivity. Two experiments were conducted during seasons 2018-2019 and 2019-2020 using a split-plot design with three blocks, five irrigation treatments (main-plots) and two phosphorous levels (sub-plots). Irrigation treatments consisted of a traditional continuous flood (CF) control and four alternatives irrigation techniques with one or two drying events during the irrigation cycle. The phosphorous fertilization levels investigated were an unfertilized control (0 kg P₂O₅ ha^-1) and the recommended fertilization level of 50 kg P₂O₅ ha^-1. Soil pH and redox potentials were measured in each treatment. Strategically-timed, low severity drying events were effective at achieving aerobic soil conditions, resulting in Eh values over 50 mV. The alternative irrigation treatment with two drying events, implemented at panicle initiation and full flowering, was the most effective in reducing inorganic arsenic in grain without affecting grain yield or the amount of irrigation water applied. This irrigation technique could be considered as an alternative management to the traditional continuous flooded to reach minimal inorganic arsenic accumulation in grain in order to attend special quality standards or specific market requirements. Accumulated inorganic arsenic in grain was below international maximum levels in all analyzed samples, with an average value of 0.084 mg kg^-1.

An automated algorithm minimising ATP failure: re-initiation to enhance anti-tachycardia pacing efficacy

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Medical Research Council, UK

Background

Re-initiation is an important mechanism of anti-tachycardia pacing (ATP) failure, whereby VT is first terminated by the initial ATP application, before being re-initiated by successive pulses. Current ICD designs are able to measure and store electrograms (EGMs) for detecting and classifying arrhythmias, which contain information that may also be used during ATP application. Developing an algorithm that automatically processes EGMs during ATP, with the goal of detecting the initial VT termination and truncating subsequent ATP pulses (which has the potential to re-initiate), may thus increase ATP efficacy.

Purpose

To develop a proof-of-concept ATP detection algorithm: Early Termination Detection Algorithm (ETDA), to automatically sense the signs of early VT termination and cease further ATP pulses based on real-time sensed EGMs from implanted devices.

Methods

A cohort of 7 porcine infarcted ventricular computational models were subject to virtual induction protocols to induce sustained VTs. Functional model properties were adjusted to provide 73 unique VT episodes (260≤VT cycle length (CL)≤480ms). For each episode, burst ATP was delivered from typical pacing sites near the right ventricle (RV) septum to evaluate its efficacy. The ATP failures and their failure mechanisms were identified, accordingly. During ATP application, five common sensing EGM vectors from implanted devices were recovered from simulations including can-to-Superior vena cava (SVC) coil, can-to-RV ring, SVC coil-to-RV coil ring, RV coil tip-to-RV coil ring and LV coil at the lateral base-to-RV tip. Our proposed ETDA utilises those EGMs for VT termination detection. Specifically, correlation coefficients (CCs) of the EGMs between two successive ATP pulses were calculated and averaged to identify sudden changes in EGM morphology that indicate VT termination (Fig A). A discriminating threshold on the CCs was chosen by comparing all re-initiation cases with detailed analysis of the actual VT termination time observed from simulation results. ETDA was then applied to all cases to identify initial termination and improvement in efficacy.

Results

Before ETDA application, ATP terminated 42 cases (58%, Fig C), with re-initiation attributing to 11 (35%) of ATP failures. Application of ETDA accurately detected VT termination in 91% of re-initiated cases, 90% of terminated cases and 81% of not-terminated cases (Fig B), which enhanced the overall ATP efficacy to 71% (P=0.08) (Fig C).

Conclusions

The real-time EGMs measured from standard ICD/CRT-D devices may be used to improve ATP efficacy through an approach such as ETDA. ETDA detects signs of early termination automatically in real time which enables identification of successful VT termination, truncating subsequent pulses that may re-initiate the VT, which enhances overall ATP efficacy.

In silico study of anti-tachycardia pacing efficacy optimisation through scar-targeted stimulation

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Medical Research Council, UK

Background

Anti-tachycardia pacing (ATP) is a reliable electrotherapy to painlessly terminate ventricular tachycardia (VT). However, ATP is often ineffective, particularly for fast VTs, which is often due to the inability of paced wavefronts to reach the re-entrant circuit, because of functional or anatomical barriers. It is thought that efficacy may be enhanced by optimised delivery closer to the re-entrant circuit driving the VT.

Purpose

To quantitatively assess the dependence of ATP efficacy upon different delivery locations with respect to the re-entrant circuit.

Methods

A cohort of 7 porcine ventricular infarct computational models were generated based on in vivo magnetic resonance imaging. Rapid-pacing protocols were applied to the cohort to induce VTs. Functional model parameters were adjusted to produce 73 episodes of sustained monomorphic VT, including 32 fast VTs (cycle length (CL)≤320ms) and 41 slow VTs (320ms-<VTCL≤<VTCL≤>480ms). Burst ATP (2 sequences of 8 pulses at 88% of VTCL) was separately delivered from 3 locations proximal to the re-entrant circuit (along the RV septum), specifically within the critical isthmus (CI), and at the Exit and Entrance sites, along with 3 locations distal to the circuit (lateral/posterior LV), based on multipolar implanted devices with LV epicardial leads, constituting 438 virtual scenarios and efficacy compared (Fig A).

Results

ATP efficacy was significantly higher for slow VTs than for fast VTs (65% vs 46%, P=0.00004) (Fig B). Separate analysis of slow VT cases revealed that delivering from distal locations to the re-entrant circuit was significantly more effective than delivering from proximal locations (72% vs 59%, P=0.04). However, for fast VT cases, the trend was reversed with proximal application (41%) being more effective than distal application (51%, P=0.15) (Fig B). Moreover, individual analysis on specific proximal locations revealed that in slow VT cases, delivering at the Exit site of VT was significantly less efficient than delivering at the Entrance site (46% vs 73%, P=0.01), with a similar (although non-significant) trend also being seen for fast VTs (44% vs 53%, P=0.5) (Fig C). Moreover, for fast VT cases, ATP delivery within the CI was overall the most effective (56%) than all other locations while this trend was not seen in slow VT cases.

Conclusions

ATP delivery proximal to the re-entrant circuit improves efficacy in fast VTs, but less so in slow VTs, where delivering from distal sites is superior. Specifically, for fast VTs, ATP delivery within the CI is the most effective. This work suggests that real-time alteration in applied ATP delivery site choice in a multipolar device (guided by the sensed VT rate by the device prior to therapy delivery) may be beneficial. Combined with the state-of-art leadless pacing technology, this also provides a clinical opportunity for patient-specific ATP delivery configuration and programming.

Virtual induction and treatment of arrhythmias (VITA): a fast automated computational tool to induce scar-related tachycardia and identify ablation targets

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): British Heart Foundation, Wellcome Trust

Background

Catheter ablation therapy of post-infarction ventricular tachycardia (VT) is often a lengthy procedure, with a high risk profile, and VT recurrence remains common. While computational modeling may aid pre-procedure planning and target identification, state-of-the-art reaction diffusion (R-D) simulations require access to high performance computing facilities, making them incompatible with clinical workflows.

Purpose

To present the Virtual Induction and Treatment of Arrhythmias (VITA), a novel, fast and fully automated computational tool to induce VT and identify subsequent ablation targets.

Methods

VITA employs multisite pacing to automatically find split activation wavefronts associated with the presence of channel isthmuses of viable myocytes within the inexcitable scar. The algorithm probes for all possible associated reentrant pathways and refines these to obtain a set of unique circuits sustaining potential clinical VTs. VT sustenance is assessed by comparing the electrical wavelength with the anatomical circuit path length. Corresponding exit sites of susceptible circuits are automatically identified, and a minimal lesion set constructed for ablation targeting. VITA also allows for rapid simulation of ECGs for clinical comparison. A summary of the VITA is shown in the Figure. VITA was tested on a virtual cohort of 7 post-infarcted porcine hearts and results compared to R-D simulations.

Results

Using only a desktop computer, VITA successfully identified all possible scar-related VT circuits and optimal ablation targets in just 48mins (per model), compared to 68.5hrs using a high-performance computer required by the R-D approach. Furthermore, VITA consistently identified more VTs associated with intra-scar circuits than R-D (Figure C).

Conclusion

VITA provides the first near real-time computational tool to aid treatment of post-infarction VTs.

In-silico optimisation of ICD defibrillation efficacy by modifying lead/can configurations using a cohort of high-resolution whole-torso heart models

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Medical Research Council, UK

Background

ICD is an effective direct therapy against VT/VF by applying a strong electrical shock across the heart between the shocking coil and can. Conventionally, patients will have a shocking coil inside the right ventricle (RV) and a can at the upper left chest. However, due to infections or other conditions, the can may need to place towards the right chest. The placement of the RV coil may also vary in different cases, for example avoiding scar. However, it is unclear how defibrillation efficacy may be altered by these unavoidable modifications to conventional lead/can configurations and whether optimisation may be possible.

Purpose

To compare defibrillation efficacy of modifications of ICD configurations in a cohort of whole-torso models.

Methods

A cohort of 15 whole torso models was generated from high resolution CT data and contrast CT cardiac scans, including 5 dilated cardiomyopathy (DCM), 5 hypertrophic cardiomyopathy (HCM) and 5 structurally normal patients (Fig A). Transvenous ICDs were represented by a shocking coil inside the RV (near apex) and a (ground) can at the upper left chest as default settings. Configurations were then varied by moving the can to the right chest, moving the RV coil up the mid-septum or adding extra grounds (Superior Vena Cava (SVC) coil, coronary sinus (CS) coil (Fig A)). Defibrillation-strength shocks were applied to all models (Fig B). DFTs and mean electrical field were evaluated across the whole heart as well as specific LV, RV, RV insertion regions, along with overall impedance.

Results

Shifting the can from left to right significantly increased DFT for the whole heart (23 J vs 15 J, P=0.03) and LV (25 J vs 17 J, P=0.03) (Fig C) and reduced the mean electrical field. Moving the RV coil further up the septum did not significantly alter DFT (Fig D), but did reduce mean electrical field for all regions and reduce impedance significantly. Additional separate coils significantly reduced DFT for all regions (Fig D) by increasing mean electrical field, whilst adding both coils significantly reduced DFT the most (whole heart: 15 J vs 6 J, P=0.03) (Fig E). Impedance was increased significantly by adding SVC coil, but reduced significantly by adding CS coil. Adding both coils increased impedance slightly.

Conclusions

Although a right-sided can increases DFT by over 50%, additional leads (grounds) may mitigate this increase by increasing mean electrical field. Moving the RV coil closer to the mid-septum reduces DFT slightly, but also reduces mean electrical field and impedance significantly.

Subthreshold delayed afterdepolarizations mediated by reduced tissue conductivity form a substrate for unidirectional block and reentry within the infarcted heart

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): British Heart Foundation, Wellcome Trust

Background

Delayed afterdepolarizations (DADs) due to spontaneous calcium release (SCR) events at the subcellular scale have been associated with arrhythmia formation in the border zone (BZ) of infarcted hearts. DADs may not only summate to form ectopic focal sources but may also inactivate sodium channels forming a substrate for unidirectional conduction block and reentry. The role played by infarct anatomy and altered intracellular coupling in facilitating this phenomenon is not fully understood.

Purpose

To use computational modelling to investigate the role of anatomical properties of the infarct BZ in creating a substrate for DAD-mediated conduction block and reentry.

Methods

MRI data from a porcine post-infarction heart was used to build the computational model. A phenomenological model was used to simulate SCRs in the BZ. Arrhythmia susceptibility was quantified by pacing the model followed by a pause, to see whether DADs would occur, and an extra S2 beat with different coupling intervals (CIs). Tissue conductivity in the BZ was decreased to investigate the effect of uncoupling on DAD-mediated conduction block.

Results

Subthreshold DADs occurring within the infarct BZ inactivated the fast sodium channels which resulted in block of S2 beats. This occurred most readily in narrow isthmuses where electrotonic load was attenuated by the non-conducting scar. DADs rendered the entire isthmus area refractory establishing a substrate for unidirectional block and reentry (see Fig. A). Reduced tissue conductivity in the BZ reduced electrotonic load on cells undergoing DADs. This led to more local tissue depolarization (Vm) as uncoupling prevented current from flowing to neighboring cells at rest (Fig. B-C). Reduced tissue conductivity also enhanced DAD-mediated block by increasing the vulnerable window for reentry initiation (700ms < S2 CI < 900ms as shown in Fig. D).

Conclusion

Subthreshold DADs provide a substrate for arrhythmogenesis in the infarct BZ. Tissue uncoupling enhanced the arrhythmogenic risk by increasing the time window of unidirectional block.

Nanostructured fibrin-based hydrogel membranes for use as an augmentation strategy in Achilles tendon surgical repair in rats

Hydrogels are polymeric biomaterials characterised by their promising biological and biomechanical properties, which make them potential alternatives for use in tendon repair. The aim of the present study was to generate in vitro, and determine the therapeutic efficacy in vivo, of novel nanostructured fibrin-based hydrogels to be used as an augmentation strategy for the surgical repair of rat Achilles tendon injuries. Fibrin, fibrin-agarose and fibrin-collagen nanostructured hydrogels (NFH, NFAH and NFCH, respectively) were generated and their biomechanical properties and cell-biomaterial interactions characterised ex vivo. Achilles tendon ruptures were created in 24 adult Wistar rats, which were next treated with direct repair (control group) or direct repair augmented with the generated biomaterials (6 rats/group). After 4 and 8 weeks, the animals were euthanised for macroscopical and histological analyses. Biomechanical characterisation showed optimal properties of the biomaterials for use in tendon repair. Moreover, biological analyses confirmed that tendon-derived fibroblasts were able to adhere to the surface of the generated biomaterials, with high levels of viability and functionality. In vivo studies demonstrated successful tendon repair in all groups. Lastly, histological analyses disclosed better tissue and extracellular matrix organisation and alignment with biomaterial-based augmentation strategies than direct repair, especially when NFAH and NFCH were used. The present study demonstrated that nanostructured fibrin-collagen hydrogels can be used to enhance the healing process in the surgical repair of tendon ruptures.

SELNET clinical practice guidelines for bone sarcoma

Bone sarcoma are infrequent diseases, representing < 0.2% of all adult neoplasms. A multidisciplinary management within reference centers for sarcoma, with discussion of the diagnostic and therapeutic strategies within an expert multidisciplinary tumour board, is essential for these patients, given its heterogeneity and low frequency. This approach leads to an improvement in patient's outcome, as demonstrated in several studies. The Sarcoma European Latin-American Network (SELNET), aims to improve clinical outcome in sarcoma care, with a special focus in Latin-American countries. These Clinical Practice Guidelines (CPG) have been developed and agreed by a multidisciplinary expert group (including medical and radiation oncologist, surgical oncologist, orthopaedic surgeons, radiologist, pathologist, molecular biologist and representatives of patients advocacy groups) of the SELNET consortium, and are conceived to provide the standard approach to diagnosis, treatment and follow-up of bone sarcoma patients in the Latin-American context.

Regional variability of arsenic content in Uruguayan polished rice

Characterization of the country internal variability of arsenic (As) accumulation in rice grain across different rice production regions is very important in order to analyze its compliance with international and regional limits. A robust sampling study scheme (n = 150 samples) was performed to determine total arsenic (tAs) and inorganic (iAs) levels from polished rice grain covering all rice producing regions along two growing seasons. The mean and median concentration of tAs were 0.178 mg kg-1 and 0.147 mg kg-¹, with a minimum and maximum value of 0.015 mg kg^-1 and 0.629 mg kg^-1, respectively and a coefficient of variation of 63.6%. The mean and median concentration of iAs were 0.062 mg kg^-1 and 0.055 mg kg^-1 respectively ranging from 0.005 mg kg^-1 up to a maximum of 0.195 mg kg^-1 and a coefficient of variation of 51.5%. A moderate correlation was revealed within iAs and tAs. Levels of iAs in all of the samples were below the international limits of 0.2 mg kg^-1 according to the international limits for human health by the Codex Alimentarius (FAO and WHO, 2019). Rice fields cultivated on soils originated from igneous geological material reported lower arsenic levels accumulated in rice grain in relation to sedimentary soils. Japonica cultivars presented significantly lower tAs and iAs concentrations than Indica ones (p = 0.0121 and p < 0.0001; respectively). Consumption of rice by male and female adults in Uruguay is safe according to its level of annual consumption and based on the mean iAs levels determined in this study.

Underreporting of mesothelioma, asbestosis and pleural plaques in Brazil

BACKGROUND

Brazil has a long history of heavy asbestos consumption. However, the number of asbestos-related diseases (ARDs) falls far below the one expected compared with other asbestos consumer countries.

AIMS

To examine underreporting of ARDs, that is mesothelioma, asbestosis and pleural plaques, in Brazil's Mortality Information System (SIM).

METHODS

Health information systems (HIS) were mapped, datasets retrieved and records of ARD deaths extracted. Records were pair-matched using anonymous linkage to create a single database. ARD-reported cases missing in SIM were considered unreported. The study's period ranged from 2008 to 2014, when every HIS contributed to the ARD records pool.

RESULTS

A total of 1298 registered ARD deaths were found, 996 cases of mesothelioma (77%) and 302 (23%) of asbestosis and pleural plaques. SIM was the major single data source of ARD but 335 mesothelioma deaths were missing, an average underreporting of 33%, with no clear time trend. For asbestosis and pleural plaques, underreporting of ARD oscillated from 55% in 2010 to 25% in 2014, a declining trend. ARD underreporting was not associated with sex or age.

CONCLUSIONS

One-third of underreported ARD deaths in the universal SIM is unacceptably high and, apparently, it has not been improving substantially over time. After recoveries from multiple databases, the number of cases is still below, which could be expected based on asbestos consumption. Interoperability of multiple information systems could enhance case detection and improve the precision of mortality estimates, which are crucial for surveillance and for evaluation of remedial policies.

Epidemiology, clinical picture and long-term outcomes of FIP1L1-PDGFRA-positive myeloid neoplasm with eosinophilia: Data from 151 patients

FIP1L1-PDGFRA-positive myeloid neoplasm with eosinophilia (F/P+ MN-eo) is a rare disease: robust epidemiological data are lacking and reported issues are scarce, of low sample-size and limited follow-up. Imatinib mesylate (IM) is highly efficient but no predictive factor of relapse after discontinuation has yet been identified. One hundred and fifty-one patients with F/P+ MN-eo (143 males; mean age at diagnosis 49 years; mean annual incidence: 0.18 case per million population) were included in this retrospective nationwide study involving all French laboratories who perform the search of F/P fusion gene (study period: 2003-2019). The main organs involved included the spleen (44%), skin (32%), lungs (30%), heart (19%) and central nervous system (9%). Serum vitamin B12 and tryptase levels were elevated in 74/79 (94%) and 45/57 (79%) patients, respectively, and none of the 31 patients initially treated with corticosteroids achieved complete hematologic remission. All 148 (98%) IM-treated patients achieved complete hematologic and molecular (when tested, n = 84) responses. Forty-six patients eventually discontinued IM, among whom 20 (57%) relapsed. In multivariate analysis, time to IM initiation (continuous HR: 1,01 [0.99-1,03]; P = .05) and duration of IM treatment (continuous HR: 0,97 [0,95-0,99]; P = .004) were independent factors of relapse after discontinuation of IM. After a mean follow-up of 80 (56) months, the 1, 5- and 10-year overall survival rates in IM-treated patients were 99%, 95% and 84% respectively. In F/P+ MN-eo, prompt initiation of IM and longer treatment durations may prevent relapses after discontinuation of IM.

Continuing and online education for health professionals in Brazil: Results from UNA-SUS

UNA-SUS System was established to enforce the National Policy of Continuing Education in Health, and it is composed of a Network of 34 public institutions (mostly Universities), responsible for online educational offerings, in response to the demands generated by the Ministry of Health. The system produces courses that are committed to the 2030 Agenda for Sustainable Development (specially Goals 3, 4, 5, 10, and 16).

Objectives

to verify the profile of users and the penetrance of UNA-SUS online courses and their contribution to the democratization of Continuing Education of health workers.

Methods

Data were collected from Arouca Platform and statistical analysis was performed by the Open Free Software R 3.6.

Results

There were more than 2.8 million enrollments, counting more than 1 million students, from every SUS health regions, Brazilian municipalities and states. Courses with the greatest demands were related to important clinical situations faced by the Primary Care professionals in Brazil. There was a predominance of women (80%), whites (36%), followed by browns (33%), singles (57%) and in the age group of 21 to 40 years (70%). Nurses, doctors and dentists were the professionals who most sought courses at UNA-SUS. No relationship was found between enrollment in population-weighted self-instructional courses and the Brazilian State HDI, but a negative relationship was established between the Gini coefficient and enrollment in courses, showing that the more unequal the region, the fewer enrolled students it had.

Conclusions

The UNA-SUS is effective in providing continuing education through free, online course offerings, reaching users from different Brazilian geographic regions, including those leaving in areas with few presential or free educational opportunities, contributing to improve the service offered by the Brazilian Public Health System.

Key messages

Continuing education for Health Professionals in Brazil using online education courses is democratic. UNA-SUS is an effective system to consolidate the National Policy of Continuing Education.

P321Subthreshold delayed afterdepolarizations form a substrate for conduction block in the infarcted heart

Funding Acknowledgements

National Institute for Health Research; British Heart Foundation; and The Wellcome Trust and Engineering and Physical Sciences Research Council.

Background

Delayed afterdepolarizations (DADs) due to spontaneous calcium (Ca) release (SCR) events from the sarcoplasmic reticulum have been implicated with a variety of arrhythmias. Such SCR events have also been reported in cells that survive in the infarct border zone (BZ). While the potential of Ca-mediated DADs to become suprathreshold and propagate in the form of ectopic beats has been well characterized, the role of subthreshold DADs in arrhythmia formation in the infarcted heart remains to be elucidated.

Purpose

To use computational modelling to investigate whether subthreshold Ca-mediated DADs may form a substrate for conduction block and reentry in the BZ. Our hypothesis is that subthreshold DADs can hinder local tissue excitability in critical infarct BZ regions by inactivating the fast sodium current (INa), leading to temporary unidirectional conduction block providing a trigger for arrhythmogenesis.

Methods

We developed an idealized infarct model of the left ventricle. The infarct region consisted of a non-conducting scar transcended by an isthmus of cells that survived myocardial infarction (border zone). These cells were made prone to Ca-mediated DADs described by a phenomenological model of SCR events. The model was pre-paced at the apex followed by a 1500ms-pacing pause to see whether DADs would emerge. An extra beat with a longer coupling interval (CI) was then applied. The following electrophysiological changes resulting from remodeling processes in the isthmus were simulated to assess their contribution to the arrhythmogenic potential of subthreshold DADs: INa loss-of-function due to a (2.5mV and 5mV) negative-shift in the steady-state channel inactivation; 50% reduction in tissue conductivity; and increased levels of fibrosis (up to 50%).

Results

On average, Ca-mediated DADs reached their maximum value 1065ms after the last paced beat (Fig. A). Despite this, in the default electrophysiological setup, simulations with extra beats with 1000ms &gt; CI &gt; 1100ms did not result in conduction block in any of the experiments. When repeated with combined changes of reduced tissue conductivity and fibrosis, subthreshold DADs were still unable to create a substrate for block. However, when combined with a 5mV-shift in INa inactivation, block at isthmus’ mouth proximal to the stimulus site was detected for extra beats 1010 ms ≥ CI ≥ 1070ms (see Fig. B). The cause of block was due to a subthreshold DAD occurring just prior to the arrival of the extra beat. All blocked beats degenerated into reentry.

Conclusions

Under most physiological conditions, subthreshold DADs are unlikely to provide a substrate for unidirectional block. However, under conditions of decreased excitability, subthreshold DADs can hinder tissue excitability in the infarcted region leading to conduction block and reentry.

Abstract Figure. DAD-mediated conduction block in the BZ

221Evaluating the ability of different substrate mapping techniques to identify scar-related ventricular tachycardia circuits using computational modelling

Funding Acknowledgements

National Institute for Health Research; British Heart Foundation; and The Wellcome Trust and Engineering and Physical Sciences Research Council.

Background

Accurate identification of targets for catheter ablation therapy of ventricular tachycardias (VTs) in the postinfarction heart remains a significant challenge. Identification of such targets often requires VT-induction to delineate the entry/exit points of the reentrant circuit sustaining the VT. However, inducibility may not be possible due to hemodynamic instability. In this scenario, substrate ablation strategies can still be performed to uncover the arrhythmogenic substrate during sinus or paced rhythm. However, substrate mapping may fail to accurately delineate the reentrant circuit resulting in VT recurrence after the procedure.

Purpose

To use computer simulations to compare the ability of different electroanatomical maps constructed following typical substrate ablation strategies to identify the VT exit site.

Methods

An image-based computational model of the porcine post-infarction left ventricle was constructed to simulate VT and paced rhythm. Electroanatomical maps were constructed based on the following features extracted from electrograms computed on the endocardial surface: activation time (AT), bipolar electrogram amplitude, signal fractionation and the reentry vulnerability index (RVI - a metric combining activation and repolarization timings to identify tissue susceptibility to reentry). Potential ablation targets during substrate mapping were compared for: highest 5% AT gradient; lowest 5% bipolar signal amplitudes; areas with fragmented signals (more than one peak); and lowest 5% RVI. The minimum distance, d, between the manually identified VT exit site and the targets was measured.

Results

The RVI performed better than the other metrics at detecting the VT exit site (see Figure). The minimum distance between sites of lowest RVI and the exit site was 3.2mm compared to 13.1mm and 15.9mm in traditional AT and voltage maps, respectively. As the scar was not transmural, parameters derived from all electrograms (including those located on dense scar regions) were used to construct the electroanatomical maps. This improved the performance of the RVI significantly, making it more specific than the other metrics as can be seen in the Figure.

Conclusions

Among all metrics investigated here, the RVI identified the vulnerable region closest to VT exit site. This finding suggests that activation-repolarization metrics may improve the detection of pro-arrhythmic regions without having to induce VT. Moreover, the RVI may be particularly well suited for detecting vulnerable regions within non-transmural scars.

Abstract Figure. VT and Substrate Mapping

Diagnostic utility and therapeutic impact of PET/CT [18F]F-Fluoromethylcholine -Choline in the biochemical recurrence of prostate cancer

OBJECTIVE

To assess the diagnostic capability of PET/CT with [¹⁸F]F-Fluoromethylcholine in prostate cancer (PC) with biochemical recurrence and its therapeutic impact.

MATERIAL AND METHODS

We included 108 patients, diagnosed with PC with biochemical criteria for recurrence. A PET/CT Choline scan was performed by dynamic pelvic and whole body study at 60min post-tracer injection. The relationship between the positive studies and the PSA value was analysed by classifying patients into three groups (<1.2/1.2-2/>2ng/ml), and the diagnostic capacity was assessed with respect to pelvic MRI and the impact on the therapeutic decision.

RESULTS

The location of recurrence was identified in 85 of 108 patients (78.7%): 34 local, 47 pelvic lymph nodes and 58 distant lesions, including retroperitoneal, mediastinal lymph nodes and distant organ lesions (bone and lung). Second tumors were diagnosed in 4 patients. No significant differences were found in the percentage of positive studies depending on primary treatment. Patients with PSA>2ng/ml showed a higher percentage of disease detection than patients with a lower PSA level, with significant differences (p<0.0001). PET/CT [¹⁸F]F-Choline was able to detect local disease, not previously known from MRI, in 29.41% of patients. PET/CT Choline had an impact on therapeutic management in 67 of 108 patients (62%).

CONCLUSIONS

PET/CT with [¹⁸F]F-Fluoromethylcholine is a useful tool in the detection of locoregional and disseminated disease of PC treated with suspicion of recurrence, providing a change in therapeutic management in 62% of patients.

Evaluation of myopic cornea lenticules. A histochemical and clinical correlation

In this work, we have analyzed the main clinical and corneal histological parameters that may be associated to the spherical equivalent (SE), age and gender of individuals with myopic refractive errors. For this purpose, 108 cornea stroma lenticules were obtained from patients subjected to ReLEx-SMILE myopia correction. Histological analyses were carried out and histochemistry and immunohistochemistry were used to quantify key histological components of the cornea stroma, including mature collagen fibers, reticular and elastic fibers, glycoproteins, proteoglycans, type-V collagen and several crystallins. Clinical and histological data were analyzed to determine their association with SE, age and gender. Results showed a significant correlation between the age range of the patients and the expression of crystallins CRY-α-A, CRY-λ1 and type-V collagen and between CRY-λ1 and corneal thickness, spherical diopters (D) and SE, although correlation between CRY-λ1 and SE was non-significant when age was controlled. Comparison of cases with low myopia and high/moderate myopia found statistical differences for D and lenticule thickness and diameter. The binary logistic regression analysis allowed us to construct a model using two clinical parameters (D and lenticule thickness). Parameters showing significant correlation with the age were the corneal radius, keratometry reading (K), OZ, CRY-α-A and type-V collagen, whereas SE, lenticule thickness, OZ, CRY-λ1 and type-V collagen showed statistically significant differences between the youngest and the oldest patients. A binary logistic regression analysis model was generated including 3 variables (D, cornea radius and OZ). No gender differences were found. The specific clinical and histological modifications found to be associated to the SE and age could be useful for a better understanding of the mechanisms involved in the genesis or progression of myopia and could establish the basement for future therapeutic options.

Effective use of mesenchymal stem cells in human skin substitutes generated by tissue engineering

Mesenchymal stem cells (MSCs) can differentiate toward epithelial cells and may be used as an alternative source for generation of heterotypical artificial human skin substitutes, thus, enhancing their development and translation potential to the clinic. The present study aimed at comparing four types of heterotypical human bioengineered skin generated using MSCs as an alternative epithelial cell source. Adipose-tissue-derived stem cells (ADSCs), dental pulp stem cells (DPSCs), Wharton's jelly stem cells (WJSCs) and bone marrow stem cells (BMSCs) were used for epidermal regeneration on top of dermal skin substitutes. Heterotypic human skin substitutes were evaluated before and after implantation in immune-deficient athymic mice for 30 d. Histological and genetic studies were performed to evaluate extracellular matrix synthesis, epidermal differentiation and human leukocyte antigen (HLA) molecule expression. The four cell types differentiated into keratinocytes, as shown by the expression of cytokeratin 10 and filaggrin 30 d post-grafting; also, they induced dermal fibroblasts responsible for the synthesis of extracellular fibrillar and non-fibrillar components, in a similar way among each other. WJSCs and BMSCs showed higher expression of cytokeratin 10 and filaggrin, suggesting these cells were more prone to epidermal regeneration. The absence of HLA molecules, even when the epithelial layer was differentiated, supports the future clinical use of these substitutes - especially ADSCs, DPSCs and WJSCs - with low rejection risk. MSCs allowed the generation of bioengineered human skin substitutes with potential clinical usefulness. According to their epidermal differentiation potential and lack of HLA antigens, WJSCs should preferentially be used.

Correlations between plasma and PET beta-amyloid levels in individuals with subjective cognitive decline: the Fundació ACE Healthy Brain Initiative (FACEHBI)

BACKGROUND

Peripheral biomarkers that identify individuals at risk of developing Alzheimer's disease (AD) or predicting high amyloid beta (Aβ) brain burden would be highly valuable. To facilitate clinical trials of disease-modifying therapies, plasma concentrations of Aβ species are good candidates for peripheral AD biomarkers, but studies to date have generated conflicting results.

METHODS

The Fundació ACE Healthy Brain Initiative (FACEHBI) study uses a convenience sample of 200 individuals diagnosed with subjective cognitive decline (SCD) at the Fundació ACE (Barcelona, Spain) who underwent amyloid florbetaben(18F) (FBB) positron emission tomography (PET) brain imaging. Baseline plasma samples from FACEHBI subjects (aged 65.9 ± 7.2 years) were analyzed using the ABtest (Araclon Biotech). This test directly determines the free plasma (FP) and total plasma (TP) levels of Aβ40 and Aβ42 peptides. The association between Aβ40 and Aβ42 plasma levels and FBB-PET global standardized uptake value ratio (SUVR) was determined using correlations and linear regression-based methods. The effect of the APOE genotype on plasma Aβ levels and FBB-PET was also assessed. Finally, various models including different combinations of demographics, genetics, and Aβ plasma levels were constructed using logistic regression and area under the receiver operating characteristic curve (AUROC) analyses to evaluate their ability for discriminating which subjects presented brain amyloidosis.

RESULTS

FBB-PET global SUVR correlated weakly but significantly with Aβ42/40 plasma ratios. For TP42/40, this observation persisted after controlling for age and APOE ε4 allele carrier status (R2 = 0.193, p = 1.01E-09). The ROC curve demonstrated that plasma Aβ measurements are not superior to APOE and age in combination in predicting brain amyloidosis. It is noteworthy that using a simple preselection tool (the TP42/40 ratio with an empirical cut-off value of 0.08) optimizes the sensitivity and reduces the number of individuals subjected to Aβ FBB-PET scanners to 52.8%. No significant dependency was observed between APOE genotype and plasma Aβ measurements (p value for interaction = 0.105).

CONCLUSION

Brain and plasma Aβ levels are partially correlated in individuals diagnosed with SCD. Aβ plasma measurements, particularly the TP42/40 ratio, could generate a new recruitment strategy independent of the APOE genotype that would improve identification of SCD subjects with brain amyloidosis and reduce the rate of screening failures in preclinical AD studies. Independent replication of these findings is warranted.

FACEHBI: A Prospective Study of Risk Factors, Biomarkers and Cognition in a Cohort of Individuals with Subjective Cognitive Decline. Study Rationale and Research Protocols

BACKGROUND

Long-term longitudinal studies with multimodal biomarkers are needed to delve into the knowledge of preclinical AD. Subjective cognitive decline has been proposed as a risk factor for the development of cognitive impairment. Thus, including individuals with SCD in observational studies may be a cost-effective strategy to increase the prevalence of preclinical AD in the sample.

OBJECTIVES

To describe the rationale, research protocols and baseline characteristics of participants in the Fundació ACE Healthy Brain Initiative (FACEHBI).

DESIGN

FACEHBI is a clinical trial (EudraCT: 2014-000798-38) embedded within a long-term observational study of individuals with SCD.

SETTING

Participants have been recruited at the memory clinic of Fundació ACE (Barcelona) from two different sources: patients referred by a general practitioner and individuals from an Open House Initiative.

PARTICIPANTS

200 individuals diagnosed with SCD with a strictly normal performance in a comprehensive neuropsychological battery.

MEASUREMENTS

Individuals will undergo an extensive neuropsychological protocol, risk factor assessment and a set of multimodal biomarkers including florbetaben PET, structural and functional MRI, diffusion tensor imaging, determination of amyloid species in plasma and neurophthalmologic assessment with optical coherence tomography.

RESULTS

Two hundred individuals have been recruited in 15 months. Mean age was 65.9 years; mean MMSE was 29.2 with a mean of 14.8 years of education.

CONCLUSIONS

FACEHBI is a long-term study of cognition, biomarkers and lifestyle that has been designed upon an innovative symptom-based approach using SCD as target population. It will shed light on the pathophysiology of preclinical AD and the role of SCD as a risk marker for the development of cognitive impairment.

Characterization of the human ridged and non-ridged skin: a comprehensive histological, histochemical and immunohistochemical analysis

The structure of the human skin is directly dependent on its location and the mechanical forces to which it is subjected. In the present work, we have performed a comprehensive analysis of the human ridged and non-ridged skin to identify the differences and similarities between both skin types. For this purpose, human skin samples were obtained from dorsal hand skin (DHS), palmar hand skin (PHS), dorsal foot skin (DFS) and plantar foot skin (PFS) from the same cadaveric donors. Histological, histochemical and semiquantitative and quantitative immunohistochemical analyses were carried out to evaluate the epidermis, dermis and basement membrane. Results show that the epithelial layer of ridged skin had larger cell number and size than non-ridged skin for most strata. Melanocytes and Langerhans cells were more abundant in non-ridged skin, whereas Merkel cells were preferentially found in ridged skin. The expression pattern of CK5/6 was slightly differed between non-ridged and ridged skin. Involucrin expression was slightly more intense in non-ridged skin than in ridged skin. Collagen was more abundant in foot skin dermis than in hand skin, and in ridged skin as compared to non-ridged skin. Elastic fibers were more abundant in DHS. Biglycan was more abundant in foot skin than in hand skin. No differences were found for blood and lymphatic vessels. The basement membrane laminin was preferentially found in foot skin. These results revealed important differences at the epithelial, dermal and basement membrane levels that could contribute to a better knowledge of the human skin histology.

Inflammation, edema and poor outcome are associated with hyperthermia in hypertensive intracerebral hemorrhages

Background and purpose

The deleterious effect of hyperthermia on intracerebral hemorrhage (ICH) has been studied. However, the results are not conclusive and new studies are needed to elucidate clinical factors that influence the poor outcome. The aim of this study was to identify the clinical factors (including ICH etiology) that influence the poor outcome associated with hyperthermia and ICH. We also tried to identify potential mechanisms involved in hyperthermia during ICH.

Methods

We conducted a retrospective study enrolling patients with non‐traumatic ICH from a prospective registry. We used logistic regression models to analyze the influence of hyperthermia in relation to different inflammatory and endothelial dysfunction markers, hematoma growth and edema volume in hypertensive and non‐hypertensive patients with ICH.

Results

We included 887 patients with ICH (433 hypertensive, 50 amyloid, 117 by anticoagulants and 287 with other causes). Patients with hypertensive ICH showed the highest body temperature (37.5 ± 0.8°C) as well as the maximum increase in temperature (0.9 ± 0.1°C) within the first 24 h. Patients with ICH of hypertensive etiologic origin, who presented hyperthermia, showed a 5.3‐fold higher risk of a poor outcome at 3 months. We found a positive relationship (r = 0.717, P < 0.0001) between edema volume and hyperthermia during the first 24 h but only in patients with ICH of hypertensive etiologic origin. This relationship seems to be mediated by inflammatory markers.

Conclusion

Our data suggest that hyperthermia, together with inflammation and edema, is associated with poor outcome only in ICH of hypertensive etiology.

Wharton's jelly-derived mesenchymal cells as a new source for the generation of microtissues for tissue engineering applications

Microtissues (MT) are currently considered as a promising alternative for the fabrication of natural, 3D biomimetic functional units for the construction of bio-artificial substitutes by tissue engineering (TE). The aim of this study was to evaluate the possibility of generating mesenchymal cell-based MT using human umbilical cord Wharton's jelly stromal cells (WJSC-MT). MT were generated using agarose microchips and evaluated ex vivo during 28 days. Fibroblasts MT (FIB-MT) were used as control. Morphometry, cell viability and metabolism, MT-formation process and ECM synthesis were assessed by phase-contrast microscopy, functional biochemical assays, and histological analyses. Morphometry revealed a time-course compaction process in both MT, but WJSC-MT resulted to be larger than FIB-MT in all days analyzed. Cell viability and functionality evaluation demonstrated that both MT were composed by viable and metabolically active cells, especially the WJSC during 4-21 days ex vivo. Histology showed that WJSC acquired a peripheral pattern and synthesized an extracellular matrix-rich core over the time, what differed from the homogeneous pattern observed in FIB-MT. This study demonstrates the possibility of using WJSC to create MT containing viable and functional cells and abundant extracellular matrix. We hypothesize that WJSC-MT could be a promising alternative in TE protocols. However, future cell differentiation and in vivo studies are still needed to demonstrate the potential usefulness of WJSC-MT in regenerative medicine.

Tissue engineering strategies for the treatment of tendon injuries: a systematic review and meta-analysis of animal models

OBJECTIVES

Recently, the field of tissue engineering has made numerous advances towards achieving artificial tendon substitutes with excellent mechanical and histological properties, and has had some promising experimental results. The purpose of this systematic review is to assess the efficacy of tissue engineering in the treatment of tendon injuries.

METHODS

We searched MEDLINE, Embase, and the Cochrane Library for the time period 1999 to 2016 for trials investigating tissue engineering used to improve tendon healing in animal models. The studies were screened for inclusion based on randomization, controls, and reported measurable outcomes. The RevMan software package was used for the meta-analysis.

RESULTS

A total of 388 references were retrieved and 35 studies were included in this systematic review. The different biomaterials developed were analyzed and we found that they improve the biomechanical and histological characteristics of the repaired tendon. At meta-analysis, despite a high heterogeneity, it revealed a statistically significant effect in favour of the maximum load, the maximum stress, and the Young's modulus between experimental and control groups. In the forest plot, the diamond was on the right side of the vertical line and did not intersect with the line, favouring experimental groups.

CONCLUSIONS

This review of the literature demonstrates the heterogeneity in the tendon tissue engineering literature. Several biomaterials have been developed and have been shown to enhance tendon healing and regeneration with improved outcomes.Cite this article: D. González-Quevedo, I. Martínez-Medina, A. Campos, F. Campos, V. Carriel. Tissue engineering strategies for the treatment of tendon injuries: a systematic review and meta-analysis of animal models. Bone Joint Res 2018;7:318-324. DOI: 10.1302/2046-3758.74.BJR-2017-0326.

Effect of particle concentration on the microstructural and macromechanical properties of biocompatible magnetic hydrogels

We analyze the effect of nanoparticle concentration on the physical properties of magnetic hydrogels consisting of polymer networks of the human fibrin biopolymer with embedded magnetic particles, swollen by a water-based solution. We prepared these magnetic hydrogels by polymerization of mixtures consisting mainly of human plasma and magnetic nanoparticles with OH^- functionalization. Microscopic observations revealed that magnetic hydrogels presented some cluster-like knots that were connected by several fibrin threads. By contrast, nonmagnetic hydrogels presented a homogeneous net-like structure with only individual connections between pairs of fibers. The rheological analysis demonstrated that the rigidity modulus, as well as the viscoelastic moduli, increased quadratically with nanoparticle content following a square-like function. Furthermore, we found that time for gel point was shorter in the presence of magnetic nanoparticles. Thus, we can conclude that nanoparticles favor the cross-linking process, serving as nucleation sites for the attachment of the fibrin polymer. Attraction between the positive groups of the fibrinogen, from which the fibrin is polymerized, and the negative OH^- groups of the magnetic particle surface qualitatively justifies the positive role of the nanoparticles in the enhancement of the mechanical properties of the magnetic hydrogels. Indeed, we developed a theoretical model that semiquantitatively explains the experimental results by assuming the indirect attraction of the fibrinogen through the attached nanoparticles. Due to this attraction the monomers condense into nuclei of the dense phase and by the end of the polymerization process the nuclei (knots) of the dense phase cross-link the fibrin threads, which enhances their mechanical properties.

Adhesive Cementation Promotes Higher Fatigue Resistance to Zirconia Crowns

Objective: The aim of this study was to investigate the influence of the cementation strategy on the fatigue resistance of zirconia crowns. The null hypothesis was that the cementation strategy would not affect the fatigue resistance of the crowns.

Methods and Materials: Seventy-five simplified molar tooth crown preparations were machined in glass fiber–filled epoxy resin. Zirconia crowns were designed (thickness=0.7 mm), milled by computer-aided design/computer-aided manufacturing, and sintered, as recommended. Crowns were cemented onto the resin preparations using five cementation strategies (n=15): ZP, luting with zinc phosphate cement; PN, luting with Panavia F resin cement; AL, air particle abrasion with alumina particles (125 μm) as the crown inner surface pretreatment + Panavia F; CJ, tribochemical silica coating as crown inner surface pretreatment + Panavia F; and GL, application of a thin layer of porcelain glaze followed by etching with hydrofluoric acid and silanization as crown inner surface pretreatment + Panavia F. Resin cement was activated for 30 seconds for each surface. Specimens were tested until fracture in a stepwise stress fatigue test (10,000 cycles in each step, 600 to 1400 N, frequency of 1.4 Hz). The mode of failure was analyzed by stereomicroscopy and scanning electron microscopy. Data were analyzed by Kaplan-Meier and Mantel-Cox (log rank) tests and a pairwise comparison (p&lt;0.05) and by Weibull analysis.

Results: The CJ group had the highest load mean value for failure (1200 N), followed by the PN (1026 N), AL (1026 N), and GL (1013 N) groups, while the ZP group had the lowest mean value (706 N). Adhesively cemented groups (CJ, AL, PN, and GL) needed a higher number of cycles for failure than the group ZP did. The groups' Weibull moduli (CJ=5.9; AL=4.4; GL=3.9; PN=3.7; ZP=2.1) were different, considering the number of cycles for failure data. The predominant mode of failure was a fracture that initiated in the cement/zirconia layer. Finite element analysis showed the different stress distribution for the two models.

Conclusion: Adhesive cementation of zirconia crowns improves fatigue resistance.

Cultural Problems Associated with the Implementation of eHealth

A major hurdle in eHealth implementation is that it is difficult to put into practice. In this study, the primary aim was to identify the main barrier associated with implementing eHealth. This study surveyed IMIA members from May to November 2015. From the results, it is clear that medical professionals were recording most of their data by hand. This paper culture is a paradigm that is difficult to break. Cultural factors are the primary barrier in eHealth implementation.

Radioguided surgery and the GOSTT concept: From pre-operative image and intraoperative navigation to image-assisted excision

Radio-guided surgery has been developed for application in those disease scheduled for surgical management, particularly in areas of complex anatomy. This is based on the use of pre-operative scintigraphic planar, tomographic and fused SPECT/CT images, and the possibility of 3D reconstruction for the subsequent intraoperative locating of active lesions using handheld devices (detection probes, gamma cameras, etc.). New tracers and technologies have also been incorporated into these surgical procedures. The combination of visual and acoustic signals during the intraoperative procedure has become possible with new portable imaging modalities. In daily practice, the images offered by these techniques and devices combine perioperative nuclear medicine imaging with the superior resolution of additional optical guidance in the operating room. In many ways they provide real-time images, allowing accurate guidance during surgery, a reduction in the time required for tissue location and an anatomical environment for surgical recognition. All these approaches have been included in the concept known as (radio) Guided intraOperative Scintigraphic Tumour Targeting (GOSTT). This article offers a general view of different nuclear medicine and allied technologies used for several GOSTT procedures, and illustrates the crossing of technological frontiers in radio-guided surgery.

Chronic periodontitis is associated with lacunar infarct: a case-control study

BACKGROUND AND PURPOSE

Chronic periodontitis (ChP) and lacunar infarct (LI) are two common diseases amongst the elderly. Although several studies have shown an association between ischaemic stroke and ChP, little is known about the relationship between ChP and LI. The study aims to investigate whether ChP is associated with the presence of lacunar stroke.

METHODS

An age- and gender-matched case-control study of 62 cases (subjects diagnosed with LI) and 60 controls is reported. Clinical periodontal measures (probing pocket depth, recession, clinical attachment level, full mouth plaque score and full mouth gingival bleeding on probing score) were assessed, and associated risk factors for periodontitis and lacunar stroke were ascertained by means of a structured questionnaire.

RESULTS

Chronic periodontitis showed a strong association with LI after adjusting for common vascular risk factors (odds ratio 4.20; 95% confidence interval 1.81-10.20; P = 0.001). Likewise, severe ChP and LI also tended to be significantly associated, independent of other vascular covariates (odds ratio 3.53; 95% confidence interval 1.07-12.77; P = 0.04).

CONCLUSIONS

Chronic periodontitis was independently associated with the presence of LI after adjusting for well-known vascular risk factors for lacunar stroke. Further observational studies are necessary to investigate the pathophysiological mechanisms that can explain this relationship.

Effect of Adhesive Cementation Strategies on the Bonding of Y-TZP to Human Dentin

This study evaluated the effects of different adhesive strategies on the adhesion of zirconia to dentin using conventional and self-adhesive cements and their corresponding adhesive resins. The occlusal parts of human molars (N=80) were sectioned, exposing the dentin. The teeth and zirconia cylinders (N=80) (diameter=3.4 mm; height=4 mm) were randomly divided into eight groups according to the factors “surface conditioning” and “cement type” (n=10 per group). One conventional cement (CC: RelyX ARC, 3M ESPE) and one self-adhesive cement (SA: RelyX U200, 3M ESPE) and their corresponding adhesive resin (for CC, Adper Single Bond Plus; for SA, Scotchbond Universal Adhesive-SU) were applied on dentin. Zirconia specimens were conditioned either using chairside (CJ: CoJet, 30 μm, 2.5 bar, four seconds), laboratory silica coating (RC: Rocatec, 110 μm, 2.5 bar, four seconds), or universal primer (Single Bond Universal-UP). Nonconditioned groups for both cements acted as the control (C). Specimens were stored in water (37°C, 30 days) and subjected to shear bond strength (SBS) testing (1 mm/min). Data (MPa) were analyzed using two-way analysis of variance and a Tukey test (α=0.05). While surface conditioning significantly affected the SBS values (p=0.0001) (C&lt;RC=CJ=UP), cement type did not (p=0.148) (CC=SA). The interaction terms were significant (p=0.014). Failure types were predominantly adhesive. Air-abrasion and the use of the universal primer improved the bond strength of zirconia to dentin compared to the control group, regardless of the type of resin cement used.

Resin Bonding to a Hybrid Ceramic: Effects of Surface Treatments and Aging

The aim of this study was to verify the effects of different surface treatments on the microtensile bond strength between resin cement and a hybrid ceramic. Thirty-two hybrid ceramic slices (8 × 10 × 3 mm) were produced and allocated among four groups according to the surface treatment: Cont = no treatment, HA = 10% hydrofluoric acid applied for 60 seconds, PA = 37% phosphoric acid applied for 60 seconds and CJ = air abrasion with silica particle coated alumina (Cojet Sand, 3M ESPE, 30 μm/2.8 bar). As a control group, eight blocks of feldspathic ceramic (8 × 10 × 3 mm) were etched by hydrofluoric acid for 60 seconds (VMII). After the surface treatments, the ceramic slices were silanized (except the Cont group) and adhesively cemented to composite resin blocks (8 × 10 × 3 mm ) with a load of 750 g (polymerized for 40 seconds each side). The cemented blocks were cut into beams (bonded surface area of ∼1 mm2). Half of the beams were aged (thermocycling of 5°C-55°C/6000 cycles + water storage at 37°C/60 days), and the other half were tested immediately after being cut. Data were analyzed by Kruskal-Wallis and Dunn tests (non-aged groups) and by one-way analysis of variance and Tukey test (aged groups; α=0.05%). The mode of failure was classified by stereomicroscopy. The surface treatment significantly affected the bond strength in each set of groups: non-aged (p=0.001) and aged (p=0.001). Before being aged, samples in the CJ, HA, and PA groups achieved the highest bond strength values. However, after being aged, only those in the HA group remained with the highest bond strength values. Adhesive failure was found most often. In conclusion, hydrofluoric acid etching should be used for surface conditioning of the studied hybrid ceramic.

Inlays made from a hybrid material: adaptation and bond strengths

The aim of this study was to evaluate the internal fit, marginal adaptation, and bond strengths of inlays made of computer-aided design/computer-aided manufacturing feldspathic ceramic and polymer-infiltrated ceramic. Twenty molars were randomly selected and prepared to receive inlays that were milled from both materials. Before cementation, internal fit was achieved using the replica technique by molding the internal surface with addition silicone and measuring the cement thicknesses of the pulpal and axial walls. Marginal adaptation was measured on the occlusal and proximal margins of the replica. The inlays were then cemented using resin cement (Panavia F2.0) and subjected to two million thermomechanical cycles in water (200 N load and 3.8-Hz frequency). The restored teeth were then cut into beams, using a lathe, for microtensile testing. The contact angles, marginal integrity, and surface patterns after etching were also observed. Statistical analysis was performed using two-way repeated measures analysis of variance (p<0.05), the Tukey test for internal fit and marginal adaptation, and the Student t-test for bond strength. The failure types (adhesive or cohesive) were classified on each fractured beam. The results showed that the misfit of the pulpal walls (p=0.0002) and the marginal adaptation (p=0.0001) of the feldspathic ceramic were significantly higher when compared to those of the polymer-infiltrated ceramic, while the bond strength values of the former were higher when compared to those of the latter. The contact angle of the polymer-infiltrated ceramic was also higher. In the present study, the hybrid ceramic presented improved internal and marginal adaptation, but the bond strengths were higher for the feldspathic ceramic.

[PET and SPECT in epilepsy]

Epilepsy is one of the most frequent chronic neurological disorders, affecting 1-2% of the population. Patients with complex partial drug resistant episodes may benefit from a surgical treatment consisting in the excision of the epileptogenic area. Localization of the epileptogenic area was classically performed with video-EEG and magnetic resonance (MR). Recently, functional neuroimaging studies of Nuclear Medicine, positron emission tomography (PET) and single photon emission tomography (SPECT) have demonstrated their utility in the localization of the epileptogenic area prior to surgery. Ictal SPECT with brain perfusion tracers show an increase in blood flow in the initial ictal focus, while PET with (18)FDG demonstrates a decrease of glucose metabolism in the interictal functional deficit zone. In this review, the basic principles and methodological characteristics of the SPECT and PET in epilepsy are described. The ictal SPECT injection mechanism, different patterns of perfusion based on the time of ictal, postictal or interictal injection are detailed and the different diagnostic sensitivities of each one of these SPECT are reviewed. Different methods of analysis of the images with substraction and fusion systems with the MR are described. Similarly, the injection methodology, quantification and evaluation of the images of the PET in epilepsy are described. Finally, the main clinical indications of SPECT and PET in temporal and extratemporal epilepsy are detailed.

Human recombinant glutamate oxaloacetate transaminase 1 (GOT1) supplemented with oxaloacetate induces a protective effect after cerebral ischemia

Blood glutamate scavenging is a novel and attractive protecting strategy to reduce the excitotoxic effect of extracellular glutamate released during ischemic brain injury. Glutamate oxaloacetate transaminase 1 (GOT1) activation by means of oxaloacetate administration has been used to reduce the glutamate concentration in the blood. However, the protective effect of the administration of the recombinant GOT1 (rGOT1) enzyme has not been yet addressed in cerebral ischemia. The aim of this study was to analyze the protective effect of an effective dose of oxaloacetate and the human rGOT1 alone and in combination with a non-effective dose of oxaloacetate in an animal model of ischemic stroke. Sixty rats were subjected to a transient middle cerebral artery occlusion (MCAO). Infarct volumes were assessed by magnetic resonance imaging (MRI) before treatment administration, and 24 h and 7 days after MCAO. Brain glutamate levels were determined by in vivo MR spectroscopy (MRS) during artery occlusion (80 min) and reperfusion (180 min). GOT activity and serum glutamate concentration were analyzed during the occlusion and reperfusion period. Somatosensory test was performed at baseline and 7 days after MCAO. The three treatments tested induced a reduction in serum and brain glutamate levels, resulting in a reduction in infarct volume and sensorimotor deficit. Protective effect of rGOT1 supplemented with oxaloacetate at 7 days persists even when treatment was delayed until at least 2 h after onset of ischemia. In conclusion, our findings indicate that the combination of human rGOT1 with low doses of oxaloacetate seems to be a successful approach for stroke treatment