Percutaneous transluminal angioplasty and stenting for symptomatic intracranial arterial stenosis: a systematic review and meta-analysis

OBJECTIVES: The cumulative safety and efficacy measures of percutaneous transluminal angioplasty and stenting (PTAS) for secondary stroke prevention in patients with symptomatic intracranial arterial stenosis (sICAS) have not previously been evaluated using a meta-analytical approach. METHODS: We conducted a systematic review and random effects meta-analysis of all available randomized controlled trials (RCTs) evaluating the safety and efficacy of PTAS (in comparison with medical therapy) for sICAS. RESULTS: Three RCTs (678 total patients) were included in the quantitative analysis. PTAS was associated with a higher risk of recurrent ischemic stroke in the territory of qualifying artery both within 30 days [risk ratio (RR) = 2.21, 95% confidence interval (CI) 1.10-4.43] and 1 year (RR = 1.92, 95% CI 1.10-3.36). PTAS was also related to a higher risk of any ischemic stroke within 30 days from the index event (RR = 2.08, 95% CI 1.17-3.71). The risk for intracranial hemorrhage was found to be higher in PTAS patients both within 30 days (RR = 10.60, 95% CI 1.98-56.62) and 1 year (RR = 8.15, 95% CI 1.50-44.34). The composite outcome of any stroke or death within 1 year (RR = 2.29, 95% CI 1.13-4.66) and 2 years (RR = 1.52, 95% CI 1.04-2.21) was higher in PTAS than in medical therapy. PTAS was associated with a higher risk of any stroke or death within 2 years in the sICAS subgroup located in posterior circulation (RR = 2.37, 95% CI 1.27-4.42). CONCLUSIONS: PTAS is associated with adverse early and long-term outcomes and should not be recommended in patients with sICAS. Further research to identify subgroups of patients who could also serve as candidates for future interventional trials along with efforts to reduce procedure-related complications are needed

Deposition of Cu and WOₓ films by thermal and hot-wire chemical vapor deposition: characterization and application of these films to microelectronics

During the first year of this thesis, the development of a novel home-made system for Chemical Vapor Deposition was fulfilled. It is a Low Pressure Chemical Vapor Deposition system with DLI (Direct Liquid Injection) of precursor equipped with a tungsten wire thus enabling the separate heating of the gas phase. The precursor used was hexafluoroacetyloacetonate Cu(l) trimethylvinylsilane, CupraSelect® which is liquid at room temperature. Using this home-made system, copper thin films were deposited thermally as well as with the aid of the tungsten hot-wire (Hot Wire Chemical Vapor Deposition, HWCVD) for various filament temperatures. The substrates used were W, TiN, SiLK, MPTMS and Low Temperature Oxide (LTO) on Si wafers. To be noted that HWCVD technique for copper deposition is presented for the first time in literature. In addition, the initial stages of Chemical Vapor Deposition were investigated on LTO and SiLK substrates activated with a self-assembled monolayer of 3-mercaptotrimethylsilane (MPTMS). Besides, WOₓ films originating from the tungsten wire without the use of precursor, were deposited via the thermal evaporation technique. All the above samples were characterized with various methods such as SEM, AFM, XPS and XRD whereas the deposition rate and the resistivity were also studied. The presented thesis was accomplished with the applications of copper and tungsten oxide thin films. Therefore, new ways of metallization and copper nanoelectrodes with very high aspect ratio were suggested and developed. Furthermore, nanostructured WOₓ films were studied for applications in chemical sensing and organic light emitting diodes (OLEDs). Finally, hot wire copper nanoparticles were developed for application in organic memories of variable resistance.Κατά το πρώτο έτος αυτής της διατριβής ολοκληρώθηκε η κατασκευή του πρωτότυπου συστήματος Χημικής Εναπόθεσης από Ατμό. Το συγκεκριμένο είναι ένα σύστημα χημικής εναπόθεσης από ατμό ελαττωμένης πίεσης με DLI (Direct Liquid Injection) του πρόδρομου (precursor) εξοπλισμένο και με ένα νήμα βολφραμίου καθιστώντας ικανή την αυτόνομη θέρμανση της αέριας φάσης. Ο πρόδρομος που χρησιμοποιήθηκε (hexafluoroacetyloacetonate Cu(l) trimethylvinylsilane, CupraSelect®) είναι υγρός σε θερμοκρασία δωματίου και ατμοποιείται σε συγκεκριμένες συνθήκες με τη βοήθεια του συστήματος DLI. Στη συνέχεια με το πρωτότυπο αυτό σύστημα εναποτέθηκαν υμένια χαλκού με θερμικό τρόπο αλλά και υποβοηθούμενα με θερμαινόμενο νήμα βολφραμίου (Θερμαινόμενου Νήματος Χημική Εναπόθεση από Ατμό, ΘΝΧΕΑ) για διάφορες θερμοκρασίες νήματος. Τα υποστρώματα που χρησιμοποιήθηκαν ήταν W, TiN, SiLK, MPTMS και LTO πάνω σε δισκία Si. Να σημειωθεί ότι με η μέθοδος ΘΝΧΕΑ για χαλκό αναφέρεται για πρώτη φορά στη βιβλιογραφία. Ακόμη, μελετήθηκαν τα αρχικά στάδια της χημικής εναπόθεσης από ατμό πάνω σε υποστρώματα LTO και SiLK ενεργοποιημένα με ένα αυτό-οργανωμένο στρώμα 3-mercaptotrimethylsilane (MPTMS). Επίσης, εναποτέθηκαν υμένια WOₓ προερχόμενα από το νήμα βολφραμίου χωρίς τη παρουσία αέριου πρόδρομου μέσω της διαδικασίας της θερμικής εξάχνωσης. Όλα τα παραπάνω δείγματα χαρακτηρίστηκαν με διάφορους τρόπους όπως SEM, AFM, XPS και XRD ενώ μελετήθηκε ο ρυθμός ανάπτυξης και η ειδική αντίσταση των δειγμάτων αυτών. Η ολοκλήρωση της παρούσας διδακτορικής διατριβής έγινε με τις εφαρμογές των υμενίων χαλκού και οξειδίου του βολφραμίου. Έτσι, προτάθηκαν και επιτεύχθηκαν νέοι τρόποι επιμετάλλωσης και δημιουργήθηκαν νανοηλεκτρόδια χαλκού με πολύ μεγάλο λόγο μήκους προς πλάτους. Ακόμη, έγινε χρήση των νανοδομημένων υμένιων WOₓ για χημική ανίχνευση καθώς και σε οργανικές διόδους εκπομπής φωτός (OLEDs). Τέλος, νανοσωματίδια χαλκού θερμαινόμενου νήματος αναπτύχθηκαν για εφαρμογή σε οργανικές μνήμες μεταβλητής αντίστασης

Establishment of an oral infection model resembling the periodontal pocket in a perfusion bioreactor system

Periodontal infection involves a complex interplay between oral biofilms, gingival tissues and cells of the immune system in a dynamic microenvironment. A humanized in vitro model that reduces the need for experimental animal models, while recapitulating key biological events in a periodontal pocket, would constitute a technical advancement in the study of periodontal disease. The aim of this study was to use a dynamic perfusion bioreactor in order to develop a gingival epithelial-fibroblast-monocyte organotypic co-culture on collagen sponges. An 11 species subgingival biofilm was used to challenge the generated tissue in the bioreactor for a period of 24 h. The histological and scanning electron microscopy analysis displayed an epithelial-like layer on the surface of the collagen sponge, supported by the underlying ingrowth of gingival fibroblasts, while monocytic cells were also found within the sponge mass. Bacterial quantification of the biofilm showed that in the presence of the organotypic tissue, the growth of selected biofilm species, especially Campylobacter rectus, Actinomyces oris, Streptococcus anginosus, Veillonella dispar, and Porphyromonas gingivalis, was suppressed, indicating a potential antimicrobial effect by the tissue. Multiplex immunoassay analysis of cytokine secretion showed that interleukin (IL)-1 beta, IL-2, IL-4, and tumor necrosis factor (TNF)-alpha levels in cell culture supernatants were significantly up-regulated in presence of the biofilm, indicating a positive inflammatory response of the organotypic tissue to the biofilm challenge. In conclusion, this novel host-biofilm interaction organotypic model might resemble the periodontal pocket and have an important impact on the study of periodontal infections, by minimizing the need for the use of experimental animal models

Percutaneous transluminal angioplasty and stenting for symptomatic intracranial arterial stenosis: a systematic review and meta-analysis

Objectives: The cumulative safety and efficacy measures of percutaneous transluminal angioplasty and stenting (PTAS) for secondary stroke prevention in patients with symptomatic intracranial arterial stenosis (sICAS) have not previously been evaluated using a meta-analytical approach. Methods: We conducted a systematic review and random effects meta-analysis of all available randomized controlled trials (RCTs) evaluating the safety and efficacy of PTAS (in comparison with medical therapy) for sICAS. Results: Three RCTs (678 total patients) were included in the quantitative analysis. PTAS was associated with a higher risk of recurrent ischemic stroke in the territory of qualifying artery both within 30 days [risk ratio (RR) = 2.21, 95% confidence interval (CI) 1.10–4.43] and 1 year (RR = 1.92, 95% CI 1.10–3.36). PTAS was also related to a higher risk of any ischemic stroke within 30 days from the index event (RR = 2.08, 95% CI 1.17–3.71). The risk for intracranial hemorrhage was found to be higher in PTAS patients both within 30 days (RR = 10.60, 95% CI 1.98–56.62) and 1 year (RR = 8.15, 95% CI 1.50–44.34). The composite outcome of any stroke or death within 1 year (RR = 2.29, 95% CI 1.13–4.66) and 2 years (RR = 1.52, 95% CI 1.04–2.21) was higher in PTAS than in medical therapy. PTAS was associated with a higher risk of any stroke or death within 2 years in the sICAS subgroup located in posterior circulation (RR = 2.37, 95% CI 1.27–4.42). Conclusions: PTAS is associated with adverse early and long-term outcomes and should not be recommended in patients with sICAS. Further research to identify subgroups of patients who could also serve as candidates for future interventional trials along with efforts to reduce procedure-related complications are needed

Hot-wire vapor deposition of amorphous MoS2 thin films

Amorphous, as shown by x-ray diffraction measurements, MoS2 films (a-MoS2) were deposited by heating a mo-lybdenum wire at temperatures between 500 and 700 \ub0C in H2S at 1 Torr. As shown by Scanning Electron Micro-scopy measurements, the morphology of samples depends significantly on the filament temperature; at low temperature samples are homogeneous and smooth, at in-termediate temperatures they exhibit a granular micro-structure and at high temperatures a columnar one. X-ray photoelectron spectroscopy measurements have shown S/Mo ratios in films varying between 2.5 and 1.5 depen-dent on filament temperature. Films also contain oxygen at atomic contents of 8 to 12 %. At a filament temperature of 600 \ub0C films are mainly composed of MoS2 also containing oxygen at an atomic ratio of 8%. Spectroscopic ellipsometry measurements made on a-MoS2 films have shown that their band gap is of the order of 1.4 eV, slightly higher than that for the bulk crystalline material. Photoluminescence spectroscopy measurements have shown that samples exhibit a doublet of peaks at 2.8 and 3 eV blue shifted relatively to MoS2 samples composed of one or two mono-layers. The above indicate that the electronic structure of crystalline atomic-layer thick MoS2 is preserved in a-MoS2 films

Advanced Neuroimaging Preceding Intravenous Thrombolysis in Acute Ischemic Stroke Patients Is Safe and Effective

Advanced neuroimaging is one of the most important means that we have in the attempt to overcome time constraints and expand the use of intravenous thrombolysis (IVT). We assessed whether, and how, the prior use of advanced neuroimaging (AN), and more specifically CT/MR perfusion post-processed with RAPID software, regardless of time from symptoms onset, affected the outcomes of acute ischemic stroke (AIS) patients who received IVT. Methods. We retrospectively evaluated consecutive AIS patients who received intravenous thrombolysis monotherapy (without endovascular reperfusion) during a six-year period. The study population was divided into two groups according to the neuroimaging protocol used prior to IVT administration in AIS patients (AN+ vs. AN−). Safety outcomes included any intracranial hemorrhage (ICH) and 3-month mortality. Effectiveness outcomes included door-to-needle time, neurological status (NIHSS-score) on discharge, and functional status at three months assessed by the modified Rankin Scale (mRS). Results. The rate of IVT monotherapy increased from ten patients per year (n = 29) in the AN− to fifteen patients per year (n = 47) in the AN+ group. Although the onset-to-treatment time was longer in the AN+ cohort, the two groups did not differ in door-to-needle time, discharge NIHSS-score, symptomatic ICH, any ICH, 3-month favorable functional outcome (mRS-scores of 0–1), 3-month functional independence (mRS-scores of 0–2), distribution of 3-month mRS-scores, or 3-month mortality. Conclusion. Our pilot observational study showed that the incorporation of advanced neuroimaging in the acute stroke chain pathway in AIS patients increases the yield of IVT administration without affecting the effectiveness and safety of the treatment

Advanced Neuroimaging Preceding Intravenous Thrombolysis in Acute Ischemic Stroke Patients Is Safe and Effective

Advanced neuroimaging is one of the most important means that we have in the attempt to overcome time constraints and expand the use of intravenous thrombolysis (IVT). We assessed whether, and how, the prior use of advanced neuroimaging (AN), and more specifically CT/MR perfusion post-processed with RAPID software, regardless of time from symptoms onset, affected the outcomes of acute ischemic stroke (AIS) patients who received IVT. Methods. We retrospectively evaluated consecutive AIS patients who received intravenous thrombolysis monotherapy (without endovascular reperfusion) during a six-year period. The study population was divided into two groups according to the neuroimaging protocol used prior to IVT administration in AIS patients (AN+ vs. AN-). Safety outcomes included any intracranial hemorrhage (ICH) and 3-month mortality. Effectiveness outcomes included door-to-needle time, neurological status (NIHSS-score) on discharge, and functional status at three months assessed by the modified Rankin Scale (mRS). Results. The rate of IVT monotherapy increased from ten patients per year (n = 29) in the AN- to fifteen patients per year (n = 47) in the AN+ group. Although the onset-to-treatment time was longer in the AN+ cohort, the two groups did not differ in door-to-needle time, discharge NIHSS-score, symptomatic ICH, any ICH, 3-month favorable functional outcome (mRS-scores of 0-1), 3-month functional independence (mRS-scores of 0-2), distribution of 3-month mRS-scores, or 3-month mortality. Conclusion. Our pilot observational study showed that the incorporation of advanced neuroimaging in the acute stroke chain pathway in AIS patients increases the yield of IVT administration without affecting the effectiveness and safety of the treatment