Picea mariana Mill.) ring width and wood density measurements and provide new evidence that wood biomass production is influenced by large-scale, internal ocean-atmosphere processes. We show that while black spruce wood biomass production is primarily governed by growing season temperatures, the Atlantic ocean conveys heat from the subtropics and influences the decadal persistence in taiga forests productivity. Indeed, we argue that 20–30 years periodicities in Sea Surface Temperatures (SSTs) as part of the the Atlantic Multi-decadal Oscillation (AMO) directly influence heat transfers to adjacent lands. Winter atmospheric conditions associated with the North Atlantic Oscillation (NAO) might also impact EC’s taiga forests, albeit indirectly, through its effect on SSTs and sea ice conditions in surrounding seas. Our work emphasizes that taiga forests would benefit from the combined effects of a warmer atmosphere and stronger ocean-to-land heat transfers, whereas a weakening of these transfers could cancel out, for decades or longer, the positive effects of climate change on Eastern Canada’s largest ecosystem.Across Eastern Canada (EC), taiga forests represent an important carbon reservoir, but the extent to which climate variability affects this ecosystem over decades remains uncertain. Here, we analyze an extensive network of black spruce ( In Eastern Canada (EC), this stocking primarily results from the growth of a single tree species, black spruce (Picea mariana Mill.), which dominates the entire ecosystem from its southern fringe (49 °N) to the tree line (57 °N). Over decadal to inter-decadal time scales, the fate of this biome and its overall efficiency for trapping carbon are thus closely tied to the response of the dominant species to climate variability.Each year, nearly 20% of the world’s forest carbon stock is sequestrated by boreal biomes2. However, ongoing and projected CO2-driven warming trends for the next decades might attenuate those limitations by promoting warmer and longer growing seasons3. Yet, to what extent those changes could benefit to taiga forests in EC remains unclear due to the scarcity of data-based studies investigating links between black spruce forest growth and climate variability in the area. Another level of uncertainty stems from the fact that naturally occurring climate variability may superimpose, amplify or even counteract the monotonic effects associated with anthropogenic warming on black spruce productivity. For example, if black spruce growth is a thermo-dependent process, then mechanisms that govern heat transport and exchanges at subarctic latitudes need to be investigated to determine how they can persistently alter forest productivity and carbon sequestration capacity.Taiga forests of EC located in the unlogged part of the boreal biome (north of 52 °N) are generally considered low-productivity ecosystems, limited by cold temperatures and short growing seasons4 represents a dominant winter mode of atmospheric variability. It resumes infra-annual to multi-decadal variations in the strength and direction of storm tracks over the North Atlantic sector5. The NAO drives an array of climate variations over North America and Europe8, with a possible extended effect on forest growth during summer in EC, as evidenced by tree ring studies conducted in the area10. Other studies have also emphasized the important influence of North Atlantic Sea Surface Temperatures (SSTs) on the state of the atmosphere during the warm season11, especially to address climatic phenomena that persist on timescales longer than decades and for which oceans are most commonly assumed to play a determinant role. Those low-frequency variations are usually summarized by the Atlantic Multi-decadal Oscillation (AMO12), a horseshoe pattern that describes SST low-frequency  fluctuations in the North Atlantic. Despite of the fact that the physical mechanisms driving the AMO remain unclear , the impact of the AMO on long-term circum-Atlantic temperature and precipitation variability is unequivoqual18.Both atmospheric and oceanic dynamics should be invoked as potential internal climate variability factors that can drive persistent changes in the productivity of taiga forests in EC. The NAOMW) calculated from both ring width and ring density measurements, and we analyzed correlations with major climatic drivers such as temperatures and precipitation, as well as teleconnections with North Atlantic sea surface temperatures (AMO variability) and atmospheric dynamics (NAO variability). Our study reveals that phases of decadal to inter-decadal, persistently high (or low) forest growth in EC were triggered by low-frequency variations in the strength of heat transfers from the North Atlantic. We conclude that ocean-generated fluctuations in climate can have a significant impact on EC’s forest productivity, possibly obscuring the effects of human-induced temperature changes.Here, we use a highly replicated network of tree ring measurements from EC’s taiga forests Fig.  to unravMW) in EC’s taiga is primarily controlled by growing season temperatures , indicating that warm springs/summers positively influence wood biomass production. The spatial coherency of the response to temperatures across the investigated area is another indication of the influence of growing season temperatures on black spruce forest productivity. Indeed, the correlations with May to August temperatures are mostly positive . Our analysis only reveals a weak influence of precipitation on MW both at the site scale and the regional scale.Wood biomass production  and latewood widths (LWW) are both very poorly correlated with growing season temperatures or precipitation Fig. EWW) and latewood densities (LWD) both respond similarly to temperatures and precipitation over the 1901–2000 period, although with different strengths. Compared to MW, EWW presents slightly weaker relationships with temperatures and tends to be better associated with spring temperatures , even more than MW or EWW. In fact, LWD presents the strongest and most spatially coherent response of all proxies forming MW. The strength of this response is mostly attributable to a clear and highly significant positive effect of August temperatures on LWD  for August temperatures. The average LWD also carries a strong regional surface temperature signal, even stronger than the one imprinted into the MW series  during the twentieth century  temperatures in the circum-Atlantic area, generating colder conditions in EC during periods of positive winter NAO  over the last century. Interestingly, a cross-spectral coherency analysis also highlights a fairly high (>0.7) and significant (<0.1) coherency for periodicities between 20 and 30 years during the same period  are filtered out from both MW and the AMO series  analysis  represents 31% of the overall North-Atlantic SST variability and clearly summarizes the dominant, basin-wide, low-frequency summer AMO variability , represents decadal to inter-decadal fluctuations of SSTs over the subpolar region of the North Atlantic ocean. The second PC highlights a particularly strong response of surface temperatures over the western portion of the North-Atlantic basin, south of Greenland. The imprint of PC2 on surface air temperatures across the North-Atlantic basin extends westwards to reach the Quebec-Labrador peninsula in EC  also shows considerable spectral power between 15 and 25 years and reveals a pattern of correlation 29. South of 52 °N, temperature have had a negative impact on growth and induced widespread growth declines driven by an increase in both evaporative demand and autotrophic respiration31. Further south, in the closed-crown boreal forest, black spruce forest stands shift from precipitation-dependant to thermo-dependant populations around the 49th parallel30. Our analysis reveals a considerably more coherent response to temperatures across the entire taiga because MW is capable of tracking temperature controls throughout the growing season. Indeed, the proxy used to calculate wood biomass production (MW) integrates variations in ring width and wood density, during both the earlywood and latewood growth phases. For example, our results revealed that two proxies involved in the calculation of MW are strongly thermo-dependent: earlywood widths (EWW) and latewood densities (LWD). The thermo-dependence of EWW implies that early spring temperatures play a crucial role in the production of wood biomass. Indeed, a detailed investigation of black spruce wood micro-cores revealed that warmer (earlier) springs favor an enhanced growth33, mainly because growth initiation occurs sooner and earlywood xylem cells grow faster under such conditions. The response of MW to temperatures also appears to be very coherent because LWD reflects the strong influence of late summer conditions on latewood formation. Relationships between LWD and late summer temperatures are well established in the literature: thick-walled latewood xylem cells form during warm  summers34, therefore augmenting wood biomass produced per unit surface (volume). LWD has a notable influence on the strength and coherency of the response of MW to summer temperatures, but the overall effect on wood biomass is dampened by LWW , confirming the relevance of decadal to inter-decadal timescales for the study of processes controlling heat fluxes in the western sub-polar North Atlantic Ocean. Based on previous works36, we hypothesize that climatic and ecological impacts triggered by summer AMO variability reflect the interactions between two dominant modes of summer SST variability and their respective impacts on surface temperature patterns across the Atlantic basin. For example, from an analysis of observational records  and GCM modeling results, Frankcombe et al.36 have highlighted decadal to inter-decadal (20–30 years long) fluctuations in SSTs and subsurface temperatures at subtropical/subpolar latitudes in the North-West Atlantic Ocean. These fluctuations could correspond to those exemplified by our PC2. In fact, 20–30 years fluctuations in summer SST patterns have been attributed to the westward  migration of surface and subsurface temperature anomalies. The mechanisms invoked to explain the westward migration of temperature anomalies across the Atlantic basin involve the development of thermal Rossby waves forced by antecedent temperature and salinity gradients. Such processes have been theorized in ocean-only models37 and represent an important component of SST variability38. Such 20–30 year periodicities are clearly discernible in SST and subsurface temperature series35, GCM simulations41 and proxy-based reconstructions of the strength of the Atlantic Meriodional Overturing Circulation (AMOC)43 which has commonly been invoked as an important driving force affecting the AMO45. Overimposed on decadal to inter-decadal SST variability, Frankcombe et al.36 have highlighted an additional source of multi-decadal variability in the North Atlantic visible on frequency bands lower than 50 years and most typically associated with the dominant pattern of the AMO. It also presents a characteristic horseshoe pattern much similar to the pattern found by PC1 in the present study. The physical mechanisms causing these basin-wide, low-frequency SST variations in the North Atlantic however remain debated13. Frankcombe et al.36 argued that they most likely result from the modulation of the decadal component of SST variability by meridional temperature and salinity exchanges between North-Atlantic and Arctic waters, further affecting ocean circulation at the scale of the basin. However, from an analysis of slab-ocean models, Clement et al.13 found that those variations can be triggered by atmospheric circulation only, without any intervention from ocean circulation.Our study revealed that EC’s growing season temperatures are among the most responsive to AMO variability across the circum-Atlantic area Fig. , especia41. Sea ice cover has a well-known impact on temperatures at subpolar latitudes, but the effect appears to be strongest in late fall and winter47. However, feedbacks from ice cover on atmospheric conditions may also extend up to the warm season. Indeed, recent research has demonstrated that decadal to inter-decadal variations in sea ice concentrations covary with both temperatures and growth of black spruce forests in EC, south of 52 °N31.Here, we argue that the North-Atlantic ocean can store the heat affecting decadal to inter-decadal changes in surface air temperatures of surrounding continental masses. However, other processes need to be invoked to explain the redistribution of heat over EC. Interactions with sea ice cover are particularly relevant in that context. This is particularly true for EC, which is surrounded by the Hudson Bay and Labrador Sea, two oceanic systems that undergo significant seasonal freezing during winter. At the scale of the circum-Atlantic region, warmer SSTs contribute to reducing sea ice concentrations in both the Labrador Sea and Hudson Bay during winter. The link between North Atlantic SSTs and sea ice concentrations is supported by state-of-the-art 1000 year modeling experiments, which confirm the negative impact of summer SSTs on the ice cover of these subpolar seasMW  has recently been proposed by Sun et al.49 and could be used to investigate these complex ocean-atmosphere interactions and their impacts on climate variability at the circum-Atlantic scale.Whereas the North Atlantic stores the heat required to stimulate EC’s taiga productivity, NAO-driven winter climate variability could contribute to initiate, amplify or increase the persistency of heat transfers from oceans to adjacent lands. Our study has shown that, just like North Atlantic SSTs, the NAO shares coherent decadal to inter-decadal periodicities with both MW Fig.  and summMW Fig. . More prres Fig. . Hence, 51. Delays could also be expected with respect to interactions between NAO, AMO and ice cover dynamics at decadal to inter-decadal timescales. For example sea ice anomalies can imprint summer North Atlantic SSTs in a way that increases the persistence of severe sea ice conditions during following years52, therefore slowing down the pace at which North-Atlantic SST anomalies may propagate to adjacent lands.One question remains to be answered: why is the response of black spruce forests to North Atlantic to SST variability lagged by 4–5 years? The delay could have a biological origin and result from a preferential allocation and re-utilization of photosynthetic products stored by trees during years of favorable growth. Even if we took good care of removing the autocorrelation component in our series, it is difficult, for now, to completely rule out this effect without a deeper investigation of high-resolution dendroecological data and associated ecophysiological modeling. Another, perhaps more realistic explanation for this delay would be that ocean-atmosphere interactions that take place in the North-Atlantic sector may take up a few years to amplify to a level that significantly impacts wood biomass production across EC’s taiga. From an ocean-only perspective, several works have confirmed that AMO variability leads changes in air temperature by a few years (3 to 5 years in average) and have associated this characteristic feature to the propagation of a thermal Rossby mode across the sub-polar North-Atlantic53 are expected benefit growth of EC’s taiga forests. However, increasing temperatures will have a positive effect only up to a certain limit. In the southernmost part of the boreal forest of eastern Canada, excess heat was associated with greater temperature-induced water stress, resulting in large-scale growth declines31. In the present study, no such growth decline was observed in the MW series, probably because average temperatures are considerably colder in the taiga ecosystem than in the southern boreal region, making temperature-induced growth declines less likely in the unlogged part of the boreal forest. Our study also implied that thermo-dependent biological processes controlling black spruce growth are linked to the state of the ocean and heat transfers from lower latitudes to subarctic environments. Thus, a possible lack of phase between anthropogenic warming trends and AMO-like patterns of SST variability in the North Atlantic could attenuate the positive effects of climate change on EC’s taiga forests. Indeed, proxy-based reconstructions and state-of-the-art modeling studies have pointed to a general slowdown of the AMOC since the beginning of the 20th century, - a slowdown that should continue at least during the first part of the 21st century43. Hypothesizing that AMOC controls part of the AMO (this common belief has however been questioned recently13), thus, a slowdown of the overturning circulation associated with colder conditions in the North-West Atlantic could cancel out, for decades or longer, the beneficial effects of human-induced warming on EC’s largest ecosystem.Our findings clarify the response of EC’s largest ecosystem to long-term temperature variability. Based on our analysis, warming temperatures anticipated for the 21st century54. Density measurements were performed at each site following established procedures55. Only discs without any anomalies  were selected. Three wood samples per tree were precisely cut in 1 mm probes and then placed in a Soxhlet apparatus with ethanol for resin extraction. After a certain acclimation time to ensure constant size and hygroscopic conditions, the probes were X-rayed. To separate latewood from earlywood measurements, the X-ray micrograph was analyzed on a DENDRO 2003 microdensitometer . A cellulose acetate calibration wedge56 was used to convert the lightness of measurement into density (g/cm3) values. This densitometry analysis provided density and width measurements for both earlywood (EWD and EWW) and latewood (LWD and LWW). Cross-dating statistics are presented in Table The tree ring network used in this study is composed of 48 sites spread out across the taiga forest of EC, north of 52 °N Fig. . At eachRt and Rt−1 are the stem radial increments at the end and beginning of a given annual ring, respectively. For thin slices of wood, it is straightforward to show that BAI (cm2) is directly proportional to basal volume increment (BVI) (cm3). Therefore:In the present study, tree ring width and density measurements (for both latewood and earlywood) were used to calculate the annual biomass of wood produced by black spruce forests at each site investigated. Basal area increments (BAIs) were calculated from tree ring widths as follows (assuming a circular cross-section):EWW and LWW as follows:Proportions of BVI formed in each fraction can be estimated from 3) into mass units (g) using density measurements . Therefore, the mass of wood  can be obtained from the dimensionally correct equation:One can finally convert the respective ring volumes  and complicates the interpretations of teleconnection phenomena that dominate on those time scales. Ideally, to investigate those teleconnections, standardisation should be conducted based on the Regional Curve Standardisation method that was conceived precisely to overcome this problem57. However, it cannot be applied in our case because we do not meet the specific criteria for that method58 .MW) and other density and ring width parameters at all sites were correlated to gridded land temperature and precipitation datasets over a common period: 1901–2000 (N = 100). For this purpose, we used gridded surface air temperatures (at 2 m), precipitation and sea surface temperatures from the ERA reanalysis project (1°)59. MW values averaged across EC were also compared to regional temperature and precipitation averages based on the same method. Analyses of teleconnections between MW and NAO60 and AMO61 over the last century (1901–2000) were based on standard correlation analysis and Morlet cross-spectral coherency analysis. In order to guard against the risk of spurious spectral coherencies, 90% significance levels were calculated based on the generation of 300 Monte Carlo AR(1) randomizations. Correlations were calculated to examine the mechanisms responsible for the teleconnection. Effective degrees of freedom were calculated in order to adjust p-values for the presence of temporal autocorrelation in the series62.Annual biomass increments (


In this study, we developed fluorescent dual pH and oxygen sensors loaded in multi-well plates for in-situ and high-throughput monitoring of oxygen respiration and extracellular acidification during microbial cell growth for understanding metabolism. Biocompatible PHEMA-co-PAM materials were used as the hydrogel matrix. A polymerizable oxygen probe (OS2) derived from PtTFPP and a polymerizable pH probe (S2) derived from fluorescein were chemically conjugated into the matrix to solve the problem of the probe leaching from the matrix. Gels were allowed to cure directly on the bottom of 96-well plates at room-temperature via redox polymerization. The influence of matrix’s composition on the sensing behaviors was investigated to optimize hydrogels with enough robustness for repeatable use with good sensitivity. Responses of the dual sensing hydrogels to dissolved oxygen (DO) and pH were studied. These dual oxygen-pH sensing plates were successfully used for microbial cell-based screening assays, which are based on the measurement of fluorescence intensity changes induced by cellular oxygen consumption and pH changes during microbial growth. This method may provide a real-time monitoring of cellular respiration, acidification, and a rapid kinetic assessment of multiple samples for cell viability as well as high-throughput drug screening. All of these assays can be carried out by a conventional plate reader. Dissolved oxygen (DO) measurement has attracted great attention because oxygen is a critical indicator for monitoring the cellular microenvironment, especially in understanding metabolism , tumor r3(TMS)2) microparticles in organosilica doped in polyurethane hydrogel as a dual pH and oxygen sensing material and deposited such dual sensors in 24 well plates for monitoring bacterial growth  is the oxygen partial pressure in the nitrogen and oxygen mixture gas.A mixture of oxygen and nitrogen gas was used to saturate aqueous solutions to tune DO concentrations by bubbling into a plate reader. Fluorescence intensities at 645 nm were measured at different DO concentrations. Fluorescence intensities of the OS2 probe decreased with the increase in DO concentration. It is well-known that PHEMA-based hydrogels have excellent oxygen permeability for contact lenses ,36. The Kas for the sensing hydrogels were calculated to be 6.14 for fresh film and 6.19 for the rehydrated film after one week drying at room temperature. Similar to the oxygen responses, rehydrated films showed slightly decreased sensitivity  by a plate reader. Results showed that time dependent OD600 were not affected by the hydrogel-based sensors in the wells  under aerobic condition at 37 °C with shaking in the 96-well sensing plate. AMP concentration dependent inhibition of oxygen consumption was observed  is a β-lactam antibiotic which could act as a competitive inhibitor of the enzyme transpeptidase for cell-wall-forming, and ultimately leads to cell lysis . For thiobserved A,C. Highobserved B,D. HighE. coli. Clear cell density dependent oxygen consumption and extracellular acidification rates were observed by using the sensor gels. Further, the sensors provided the capability for studying the effects of antibiotics on cell oxygen respiration and cellular acidification. Although the current sensor formats still exhibited photo-instability and temperature effects during the measurements, our results demonstrated herein a new avenue to broaden the oxygen and pH sensor’s applications in biological fields for in-situ and high throughput analysis of pH and dissolved oxygen in cellular micro-environments. It is expected that this type dual-functional biocompatible sensing hydrogel can be used for understanding of cell growth, proliferation, and cell metabolism.New hydrophilic PHEMA-co-PAM hydrogel-based oxygen/pH dual sensing films were fabricated on the bottom of commercial multi-well plates through redox polymerization. The sensors’ sensitivity was optimized by adjusting the proportions of the hydrogel matrix components PHEMA, PAM, and the cross-linker PEGDMA. The final composition for good sensing performance was found to be a weight ratio of HEMA:AM:PEGDMA of 85:15:10. To get flat and uniform hydrogel films in the 96 well pates, a thin layer of butyl alcohol was placed on the top of the mixed monomeric precursors for gel formation in each micro-well. The sensor films with the aid of butyl alcohol are quite flat and smooth. The hydrogels could be reused and were robust enough to be washed, dried, rehydrated and stored in air for at least 1 week. Such functional 96-well plates were used for simultaneously monitoring the changes of pH and oxygen during the growth of


Streptococcus species are the most abundant genera in the oral microbiota. The prevalence of antibiotic resistant oral streptococci is on the increase and the most reported antibiotic resistance profile in oral streptococci include, among several antibiotics, resistance to β-lactams antibiotics, macrolides and tetracycline. Several studies have shown that majority of the antibiotic resistance genes that have been isolated in oral streptococci are usually associated with mobile genetic elements such as plasmids and conjugative transposons. In the current study, we used molecular based techniques to screen a total of 100 clinical oral streptococci strains isolated in Norway for the presence of Tn916/Tn916-like elements. We also investigated the diversity of these elements in oral streptococci by Restriction Fragment Length Polymorphism (RFLP) and DNA sequencing. It was found that a total of 34 strains were positive for tetracycline resistance gene, tet(M), and integrase gene (int) belonging to the Tn916-like family. The minimum inhibitory concentration (MIC) of these tetracycline-resistant oral streptococci ranged between 2-64 µg/mL. Most of the positive strains for tet(M) and int genes harbor the wild type Tn916 and a few harbor other Tn916-like elements suggesting high versatility of the Tn916 element in oral streptococci in Norway.


We present a 65-year-old male who received rivaroxaban therapy prior to and after left knee replacement surgery. The patient developed generalized weakness soon after stopping rivaroxaban. An electrocardiogram showed acute infero-lateral ischemia and an echocardiogram reported an akinetic antero-apical wall segment, an apical clot and a reduced systolic function. A subsequent coronary angiogram revealed two-vessel coronary artery thrombosis. The case illustrates a temporal relationship of coronary thrombosis following rivaroxaban cessation. This case discusses the relationship of rivaroxaban cessation and adverse events. The patient underwent a left knee replacement surgery; rivaroxaban was used prior to surgery and discontinued 12 days post-operatively. A pre-operative myocardial stress test was normal. After rivaroxaban cessation, the patient developed an acute coronary event.A 65-year-old male with hypertension and hyperlipidemia complained of generalized weakness after his left knee replacement 2 weeks ago. Physical exam was unremarkable except a borderline-low blood pressure.His electrocardiogram showed sinus rhythm, ST segment elevation with deep Q-waves in antero-septal precordial leads and isolated ST segment elevation in infero-lateral leads. The patient used rivaroxaban ™ prior to his surgery that was stopped 12 days post-operatively. He was referred immediately for cardiac catheterization, and his blood pressure responded well to saline bolus .A limited echocardiogram showed akinetic antero-apical segment (left anterior descending artery (LAD) territory) with apical clot and severely reduced left ventricular (LV) systolic function suggesting a recent anterior wall myocardial ischemia.A pre-operative myocardial perfusion-scan prior to his knee surgery showed a satisfactory LV systolic function and no evidence of reversible myocardial ischemia.Coronary angiograms revealed a double vessel coronary disease with 80% lesion in mid right coronary artery and 100% total occlusion of mid LAD. No left-to-left or right-to-left collaterals to LAD were seen. LV angiogram was not performed due to the presence of apical clot on echocardiography .In view of his late presentation, the LAD lesion was not considered acute but recent thus deemed to have no benefit of primary percutaneous coronary intervention, and percutaneous coronary intervention of right coronary artery was preceded. The intervention was successful with TIMI 3 flow post stenting. The patient tolerated the procedure well. Day one post-operatively, the patient was asymptomatic with stable vital signs. Shortly after, he witnessed a sudden cardiac arrest of pulseless electrical activity followed by ventricular fibrillation not responding to conventional treatment. A bedside echocardiogram revealed a large pericardial effusion and non-contractile ventricles suggestive of LV wall rapture. The patient was pronounced dead the same day after unsuccessful resuscitation.The novel anticoagulants are considered advancement in medical therapy where oral drugs are used conveniently without frequent monitoring. Being at the convergence point of the intrinsic and extrinsic clotting pathways, factor Xa has been the target for these novel anticoagulants therapies .Binding to the negatively charged phospholipid surfaces of the activated platelets, together with factor Va and factor Xa, leads to the formation of the prothrombinase complex, the central prothrombin activator, which finally converts prothrombin to thrombin, the major player in the clotting process. It has a rapid onset and a reversible action on the inhibition of factor Xa activity as it binds directly to the active site of factor Xa via the S1 and S4 pockets .Although the FDA has approved the use of rivaroxaban in non-valvular Afib and venous thrombo-embolism secondary prevention, a black box warning has been issued about the increased thrombotic events with cessation of therapy.In phase III clinical trial for rivaroxiban use for thromboprophylaxis after hip arthroplasty, cardiovascular events were similar between the rivaroxaban group and enoxaparin group during the study. However, during follow-up, eight events (four coronary events) occurred in seven patients in the rivaroxaban group compared to one event in the enoxaparin group .In ROCKET AF trial, the increased risk of stroke and non-CNS embolism observed in rivaroxaban group compared with warfarin group after the end of the study was explained by the absence of therapeutic anticoagulation coverage during such a transition and likely represents the intrinsic stroke rate of patients at moderate to high risk without therapeutic anticoagulation. Invasive procedures were the most common reasons for anticoagulant therapy interruptions with a median duration of 6 days .Is rivaroxaban discontinuation associated with a pro-thrombotic rebound effect? It seems counterintuitive to explain the excess strokes in rivaroxaban patients as a result of under anticoagulation in the post-trial period and the high bleeding risk in these patients at the same time .EINSTEIN investigators showed similar vascular events rivaroxaban compared to the standard therapy among the patients treated for venous thrombosis and pulmonary embolism , 7. WhilThe rebound phenomenon has been hypothesized for warfarin, but in case of rivaroxaban, it is not clear yet. Two cases of coronary thrombosis have been reported within less than a week of traditional anti-coagulation discontinuation . In otheThese reports and others raised the concern about the presence of a hypercoagulable state of the blood incident to the release of anticoagulation in patients whose clotting has been significantly depressed by anti-coagulant drugs. Others suggested that the cause is a “catching up” of the obliterating coronary artery disease .In our report, the non-invasive work-up did not reveal any evidence of a significant coronary artery disease but within few days of rivaroxaban cessation, our patient presented with a sub-acute coronary thrombosis that ended up in a devastating event.The FDA analytic review of the death events, and specifically myocardial infarction as a cause of mortality, showed no difference between rivaroxaban and warfarin. Those events were numerically in favor of rivaroxaban .Van Thiel et al raised the concern about this cardiovascular rebound phenomenon recommending additional clinical validation to establish the safety of rivaroxaban .Although it seems to be wise to minimize the interruption in anticoagulant therapy, the clinical benefit from bridging anticoagulation in patients who are transitioned from rivaroxaban to warfarin is still unclear. Bridging with ASA is another consideration.In conclusion, acute coronary event is a possible post marketing adverse event after discontinuation of rivaroxaban therapy. Individual risk factors would increase the risk of such adverse events. Alternative therapy is yet to be considered in these high-risk patients.


Streptococcus pneumoniae (S. pneumoniae). PspA variants are structurally and serologically diverse and help evade complement-mediated phagocytosis of S. pneumoniae, which is essential for its survival in the host. PspA is currently been screened for employment in the generation of more effective (serotype independent) vaccine to overcome the limitations of polysaccharide based vaccines, providing serotype specific immune responses. The cross-protection eliciting regions of PspA localize to the α-helical and proline rich regions. Recent data indicate significant variation in the ability of antibodies induced against the recombinant PspA variants to recognize distinct S. pneumoniae strains. Hence, screening for the identification of the topographical repertoire of B-cell epitopes that elicit cross-protective immune response seems essential in the engineering of a superior PspA-based vaccine. Herein, we revisit epitope identification in PspA and the utility of hybridoma technology in directing the identification of protective epitope regions of PspA that can be used in vaccine research.Pneumococcal surface protein A (PspA) is one of the most abundant cell surface protein of  Streptococcus pneumoniae (or pneumococcus) is a Gram-positive bacterium that asymptomatically colonizes the upper respiratory tract of humans. Colonization of the nasopharynx by S. pneumoniae involves adherence of the bacterium to the epithelial surface via different surface molecules (S. pneumoniae can migrate to the lungs (pneumonia), blood (bacteremia), middle ear (otitis media) and sometime cross the blood-brain barrier (meningitis) in humans  is one of most abundant surface molecules and a major determinant of protective immunity. Study of the role of PspA in virulence through insertion duplication mutagenesis revealed that PspA is essential for nasopharynx colonization . AdditioS. pneumoniae serotypes.Though PspA was originally identified by protective monoclonal antibodies (mAbs) raised in CBA/N mice , 1986, cOn analyzing the N-terminal half of PspA from the clade 2 strain Rx1 against known members of other clades, sequence homology of amino acids was found in the range of 45 (EF3296) -78% (BG9739) . As α-heFigure 1A), analysis of N-terminal half (1–288 amino acid residues) of PspA from strain Rx1 show a seven-residue periodicity in non-polar amino acid distribution  were found associated with the coiled core formation and the remaining  was found having role in promoting the helix formation. Similarity in structure corresponding to 1 through 288 amino acid residues suggests a central coiled-coil conformation of PspA from the strain Rx1 . Existence of PspA as a monomer through ultracentrifugation and spectra observed in the circular dichroism study indicates PspA of having more than 70% α-helical content , which results in the faster clearance of pneumococci by phagocytic cells bearing the C3b receptors .Attributing Recognizing different subset of pneumococcal strains, seven anti-PspA mAbs were divided into two groups on the basis of their reactivity. It was found that all epitopes recognized by these mAbs were surface accessible . SurprisEmergence of non-vaccine serotypes poses a great challenge in the management of pneumococcal diseases. These concerns are driving efforts to develop a ‘universal’ pneumococcal vaccine that is immunogenic in all age groups and broadly cross protective against all serotypes. Efforts are being made to develop a serotype independent protein based vaccine to prevent pneumococcal infections. Rather than targeting a single candidate protein, targeting a complex of proteins based on their roles in bacterial pathogenicity and physiology seems appropriate. Several studies have reported use of two or more proteins for achieving additive and broad protection against pneumococci in mice .Figure 2C) with potential to act as effective immunogens in a multi-component protein-based pneumococcal vaccine or as a carrier protein in conjugate vaccine would confer broader resistance to pneumococci. With this, protein based vaccines are considered as a better replacement of capsular-polysaccharide based vaccines.The rapid emergence of resistance to antimicrobials like penicillin has complicated the global management of pneumococcal disease. The polysaccharide vaccines have several shortcomings which include its limited serotype coverage and poor immunogenicity in high-risk groups. To this, replacement of the vaccine serotypes by other non-vaccine serotypes is currently being perused. However, increasing the number of serotypes in the vaccine increases the cost of preparation that may limit its deployment in under-developing and developing countries. These concerns are driving efforts to develop universal pneumococcal vaccine that is immunogenic in all age groups and broadly cross protective against all serotypes. As proteins are antigenically conserved across epidemiologically relevant serotypes, it is assumed that coupling proteins  coverage for possible implementation as a vaccine candidate  serotype 1 collection of andidate . IndividRepresented as hotspot of recombination events, PspA undergoes highest number of transforming events to evade host antibody response . To thisNK conceived the idea; NK and AJ equally contributed to writing of the manuscript and to preparation of figures.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


Background: Lymphoepithelial-like carcinoma (LEC) is rarely found in organs outside the nasopharyngeal area. This is the first case report of Epstein–Barr virus (EBV)-associated LEC of the extrahepatic tract. As it is very difficult to distinguish between LEC and adenocarcinoma in the clinical presentation, this article can give more insight into how the pathological analysis can help with the diagnosis.Case presentation: A 37-year-old Caucasian male with a history of Crohn's disease and primary sclerosing cholangitis presented with cholestasis. A computed tomography scan revealed a tumor in the pancreatic head without invasion into the surrounding organs. The patient underwent an uncomplicated pylorus-preserving pancreaticoduodenectomy, with pathology revealing an epithelial carcinoma of the common bile duct with metastases in 4 of the 18 resected lymph nodes. In situ hybridization demonstrated extensive EBV positivity in the tumor cells, and in serum, positive IgG anti-EBV was found. The diagnosis of EBV-associated LEC was hereby confirmed. The postoperative course was uneventful and 18 months after surgery there is no recurrence.Conclusion: In the case of an epithelial tumor in the periampullary region, one should consider EBV-associated LEC as this tumor may have a lot of similarity with the adenocarcinoma but has lower rates of recurrence after surgery and better overall survival. The diagnosis of biliary tract LEC is of importance to the physician as well to the patient, as these tumors are characterized by lower rates of recurrence and better overall survival.2 Here, we report the first EBV-related LEC of the extrahepatic biliary tract.Lymphoepithelial-like carcinoma (LEC) is usually seen in nasopharyngeal carcinoma and mostly associated with Epstein–Barr virus (EBV) infection.A 37-year-old Caucasian male with a history of Crohn's disease and primary sclerosing cholangitis presented with cholestasis. A magnetic resonance cholangiopancreatography showed a tumorous process in the pancreatic head with a double duct sign. Endoscopic ultrasound revealed a hypoechoic lesion of 3 cm in the pancreatic head with a pancreatic duct dilatation of 5.5 mm. Endoscopic retrograde cholangiopancreatogram was performed with placement of a pigtail stent in the pancreatic duct, but cannulation of the common bile duct was not possible. A computed tomography scan revealed a tumor in the pancreatic head without invasion into the surrounding organs .In situ hybridization demonstrated extensive EBV positivity in the tumor cells (As our working diagnosis was pancreatic cancer, our patient underwent an uncomplicated pylorus-preserving pancreaticoduodenectomy. The surgical specimen revealed a tumor arising in the common bile duct with pancreatic involvement, and possible extension to the duodenum and into surrounding fat tissue . The his2 To the best of our knowledge, there is only one published case that reported LEC in the distal bile duct,3 our case being the first EBV-related carcinoma of the extrahepatic biliary tract.EBV-associated LEC is rarely found in organs outside the nasopharyngeal area. Case reports described the occurrence of LEC in virtually every organ.


High plantar pressures are implicated in the development of diabetes-related foot ulcers. Whether plantar pressures remain high in patients with chronic diabetes-related foot ulcers over time is uncertain. The primary aim of this study was to compare plantar pressures at baseline and three and six months later in participants with chronic diabetes-related foot ulcers (cases) to participants without foot ulcers (controls).Standardised protocols were used to measure mean peak plantar pressure and pressure-time integral at 10 plantar foot sites  during barefoot walking. Measurements were performed at three study visits: baseline, three and six months. Linear mixed effects random-intercept models were utilised to assess whether plantar pressures differed between cases and controls after adjusting for age, sex, body mass index, neuropathy status and follow-up time. Standardised mean differences (Cohen’s d) were used to measure effect size.p = 0.005, Cohen’s d = 0.36) and mid-foot  and a higher pressure-time integral at the hallux , metatarsal 1  and mid-foot  compared to controls throughout follow-up. A reduction in pressure-time integral at multiple plantar sites over time was detected in all participants .Twenty-one cases and 69 controls started the study and 16 cases and 63 controls completed the study. Cases had a higher mean peak plantar pressure at several foot sites including the toes (Plantar pressures assessed during gait are higher in diabetes patients with chronic foot ulcers than controls at several plantar sites throughout prolonged follow-up. Long term offloading is needed in diabetes patients with diabetes-related foot ulcers to facilitate ulcer healing. Patients with diabetes-related foot ulcers (DFUs) have poor health-related quality of life and are at risk of prolonged hospitalisations –3. DFUs High plantar pressures have been implicated in the development of DFU by increasing the mechanical stress experienced by plantar tissue in the presence of diabetic peripheral neuropathy (DPN) –13. PrevThe aim of this study was to investigate plantar pressures at baseline and three and six months later in participants with DFUs (cases) compared to participants without DFUs (controls). We hypothesised that cases with DFUs would have significantly higher plantar pressures at baseline compared to controls and that these plantar pressure differences would remain during follow-up at three and six months.This was a longitudinal study which was nested in a case-control study. The study protocol and the baseline results of the study were previously published , 19. AllTwenty one participants with active unilateral plantar DFUs of more than 3 months duration (cases) and 69 type 2 diabetes mellitus participants without ulcers (controls) were initially recruited for this longitudinal study . InclusiAll anthropometric, haematological and clinical measurements were performed according to the study protocol . MeasureAll participants received standard care between follow up visits external to their involvement in the study . For cas® pressure plate  was used for plantar pressure assessment along with the associated Foot Scan ® processing software. Plantar pressures were measured in both feet at baseline, three and six months follow-up visits. All cases with DFUs were given a standard single-layer generic film wound dressing to wear over the wound during gait examination to minimise the impact of wound dressings on the study results and to standardise the type of dressing during gait assessments and to minimise the risk of wound infection , three cases (two due to orthopaedic surgery and one due to acute lower back pain) and two controls (one due to coronary artery bypass and one due to inability to attend) withdrew from the study. Prior to the six month follow-up visit [IQR 6–11.5 months], another three controls  also withdrew.p = 0.006).The baseline data from this cohort were reported in an earlier manuscript . Table 12) and a slight increase in mean ulcer area at the second follow-up (Δ = 3.4 [3.6] mm2). The stance phase duration seemed to be longer in cases compared to controls throughout follow-up. Four (19.0%) DFUs healed during follow-up and remained healed  and the mid-foot  throughout follow-up compared to controls  , metatarsal 1  and the mid-foot  in all participants (see Cases had a significantly higher mpp at toes 2–5 (rols see . Convers.38) see . Mpps deants see . The intp<0.001, d = 0.42), plantar metatarsal 1 , the mid-foot , the medial heel  and the lateral heel  throughout follow-up compared to controls , all metatarsals, including metatarsal 1  and the mid-foot  decreased during follow-up in all participants  were higher at multiple sites in cases with chronic DFUs compared to diabetes controls throughout a six month follow-up period. Overall, mpps and ptis at several sites significantly reduced over time in all participants. Although shorter wound healing times have been achieved by reducing plantar stresses on ulcerated tissue using offloading devices , whetherA number of longitudinal studies have previously assessed the association of plantar pressures with the subsequent risk of developing DFUs –37. HoweOur findings also suggest that overall plantar pressures reduced during repeated assessment. One possible reason for this is a familiarisation effect with repeated plantar pressure assessment. A previous study reported reductions in plantar pressure from baseline to follow-up for a majority of plantar sites in healthy participants . This maOur results support the need for sustained pressure offloading in patients with a history of chronic DFUs. Whether long term monitoring of plantar pressures can improve management of DFUs is controversial. Bus et al. (2011) suggested the use of in-shoe plantar pressure assessments to better inform pressure off-loading in participants with DPN at risk of developing DFU . DespiteA key area of future research focus in the field should be to characterise the important predictors of elevated plantar pressures in people with active DFUs. Recent work has outlined that foot-deformity and foot structure may be predictors of higher mid-foot plantar pressure in people with DPN and a history of DFUs . AlthougThe limitations of our study include a small sample size in combination with a rather large number of statistical comparisons, the limited number of co-variates able to be used in statistical analyses and the inability to assess the association of plantar pressure and ulcer healing due to a small number of healed ulcers. It is also likely that reductions in plantar pressures that were observed were more representative of controls rather than cases as we had more controls than cases. The poor healing rate observed in our study (4 DFUs or 19% during six months follow-up) is representative of the inclusion criteria we used (i.e. people with DFUs of more than 3 months duration). Hence our results are representative of people with chronic DFUs and supports our earlier finding that following DFU healing, plantar pressures remain higher in people with a history of DFUs . TherefoAs mentioned earlier, site specific mpp and pti have a variable level of reproducibility with repeated observations which may have also influenced our follow-up results . We asseThe strengths of this study include the longitudinal design, the reporting of reproducibility prior to data collection  and the Our results highlight the importance of offloading in the long-term management of people with DFUs . As the The findings from this study suggest that plantar pressures assessed during gait are higher in diabetes patients with chronic DFUs than controls throughout prolonged follow-up at several plantar sites. Long term offloading is needed in diabetes patients with chronic DFUs to facilitate ulcer healing.S1 File(DOCX)Click here for additional data file.S2 File(DOCX)Click here for additional data file.S3 File(DOCX)Click here for additional data file.


Staphylococcus aureus, Acinetobacter baumanii, Klebsiella pneumoniae). Moreover, colonization has been identified as a risk factor for subsequent infections in critically ill patients [Contamination of inanimate surfaces and equipment may play a role in cross-transmission of bacteria in the intensive care unit (ICU), despite current standards of terminal cleaning –3. This patients , 5.I2 statistic.We searched Medline, Scopus, and CINHAL databases for either prospective or retrospective studies reporting data on ICU-acquired bacterial species and carriage status of the same species by the prior bed occupant. An exclusion criterion was the non-ICU setting due to differences in terminal cleaning procedures and the hospital environment of the patients. We applied no language restrictions and did not consider gray literature. We performed a random-effect meta-analysis (Mantel-Haenszel method) of included studies and calculated the odds ratio (OR) for acquiring specific microorganisms as well as from the pooled data Fig. . We asseThe full search strategy can be found as Additional file I2 = 61%, P = 0.01). Figure We selected six studies for inclusion  for a total of 33,494 patients. The list of included studies and references is available as Additional file Patients admitted to ICU beds of prior occupants who were carrying bacterial pathogens should be considered at increased risk of ICU-acquisition compared to other ICU patients. It should be highlighted that these results refer to acquisition of bacteria and not to infection. However, it may be argued that acquiring bacteria may lead to colonization and nosocomial infections during the ICU stay due to disruption of natural barriers for invasive procedures , use of broad-spectrum antibiotics, and impaired immunological function. A possible explanation for these results is that bacteria frequently encountered in the ICU, especially MDR, may have the ability to survive standard terminal cleaning procedures in the environment close to the patients after discharge. Further research should evaluate the role of bacteria acquisition from prior ICU bed occupants in terms of patient-related outcomes and the impact of new strategies for terminal cleaning to reduce hospital-acquired infection.Additional file 1:Search strategy. Search strategy adopted for the systematic review. (PDF 34 kb)Additional file 2:List of included studies. Table reporting the studies included in the meta-analysis. (PDF 62 kb)


Drug-eluting stents have improved the efficacy of percutaneous coronary intervention and made it the preferred therapy in the treatment of ischemic heart diseases including acute coronary syndromes. The objective of the study was to compare the clinical efficacy and safety of sirolimus-eluting stent with that of zotarolimus-eluting stent following percutaneous coronary intervention for acute coronary syndrome patients with C-type left anterior descending stenosis.A total of 154 acute coronary syndrome patients with C-type lesions in the left anterior descending artery, requiring a stent > 28 mm in length, were randomized into two groups to receive either sirolimus- (n = 74) or zotarolimus-eluting stent (n = 80). The follow-up period after stent implantation was approximately 36 months. The primary endpoint was a major cardiac event , and the secondary endpoint included these individual end points plus stent thrombosis.After 3 years follow-up, the rate of the primary end point  was 16% in the sirolimus group (n = 12) versus 11.2% in the zotarolimus group (n = 9) (P = 0.2). Although there were four cases of stent thrombosis with sirolimus-eluting stent and one with zotarolimus-eluting stent , neither non-Q myocardial infarction  nor stent thrombosis, differed significantly.Although zotarolimus-eluting stent implantation showed more favorable results with respect to stent thrombosis and major adverse cardiac event rates compared to sirolimus-eluting stent implantation, statistically, both stent groups have nearly similar clinical safety and efficacy in the treatment of acute coronary syndromes with C-type lesions in the left anterior descending artery disease. Coronary revascularization (percutaneous and/or surgery) is the major treatment of patients presenting with acute coronary syndromes (ACS) which is a common manifestation of atherosclerotic disease. The advent of the bare metal stents (BMS) and the following drug-eluting stents (DES) have improved the efficacy of percutaneous coronary intervention (PCI), and made it the preferred therapy in the treatment of ischemic heart diseases including ACS . NeverthAlthough there is a plethora of DES trials regarding native coronary artery lesions, there are limited data comparing the first and second generation DES for the treatment of ACS patients with C type LAD lesions. The present study was conducted in the light of the conflicting results of some trials where sirolimus-eluting  and zotarolimus-eluting  stents were used in the treatment of coronary artery disease. The objective was to compare the clinic and angiographic outcomes of SES as a first generation DES, and ZES as a second generation DES. The authors hope to have made some contribution to the decision making process with regard to the choice of drug eluting stents for the treatment of ACS patients with C type native LAD lesions.This prospective study was conducted from February 2005 to March 2008. The duration of follow-up was 4 years and here we report the 3 years outcome. The study population was comprised by 154 ACS patients with C-type LAD disease undergoing implantation of an average of 31 ± 3 mm Sirolimus- (n = 74)  or 33 ± 5 mm long Zotarolimus- (n = 80)  eluting stent. Patients were eligible if they had a history of unstable angina (UA) and signs of myocardial ischemia. Patients were also required to have a de-novo target lesion in the LAD of 51% to 99% stenosis needing a stent > 28 mm in length . Exclusion criteria were patients with CAD history , chronic total occlusion, and lesions needing a < 28 mm stent.Written informed consent was obtained from all subjects, and the study protocol was approved by the local ethical committee. The angiographic inclusion and exclusion criteria were reassessed after initial angiography at the start of the procedure. All C-type LAD lesions were identified and recorded as such. Cineangiograms were analized using a validated edge system . Then patients were randomly assigned in a single-blinded manner for treatment with a SES or a ZES.All patients received aspirin (at least 100 mg once daily) and clopidogrel 75 mg once daily, or ticlopidine 250 mg twice daily at least three days before the procedure, with a loading dose of 300 mg of clopidogrel to patients not pretreated. Unfractionated heparin (UH) was administered at the beginning of the procedure at the dose of 100 IU/kg to achieve an activated clotting time > 250 s. The patients received intracoronary nitroglycerin (0.1 to 0.2 mg) before initial and final coronary angiograms to achieve maximal vasodilatation. Glycoprotein (GP) IIb/IIIa inhibitors were administered at the discretion of the operator. All patients were maintained at antiplatelet therapy after the procedure . The PCI procedure and stent implantation were performed using standard methods, through a femoral or radial approach. A C-type lesion was defined as a diffuse (> 2 cm length), excessive tortuosity of the proximal segment, extremely angulated (> 90 degrees), inability to protect major side branch [Angiographic success was defined as Thrombolysis in Myocardial Infarction (TIMI) flow grade III and < 30% residual diameter stenosis by visual assessment. Restenosis was defined as > 50% stenosis in diameter by qualitative coronary angiography within a previously stented segment. For the assigned study stent, device success was defined as ≤ 50% diameter stenosis of the target lesion, and procedural success was defined as device success with no in-hospital major adverse coronary event (MACE). Angiography was scheduled at six months or earlier if clinically indicated.Clinical follow-up was performed by either telephone contact or office visits at 1, 6, 12, 24, 36 months. All patients were invited for repeat coronary angiography between 6, 12 and 36 months; however, participation in angiographic follow-up was not mandatory for inclusion in the study. Relevant data were collected and entered into a computerized database by specialized personnel at the cardiovascular interventional heart center. Patients were asked specific questions about the development of angina according to Braunwald Classification of unstable angina. They were also monitored for (MACE), a composite end point comprising cardiac death, myocardial infarction (MI), and target vessel revascularization (PCI/CABG).Intraprocedural stent thrombosis was defined as an angiographically confirmed intraluminal filling defect within the stent resulting in TIMI anterograde flow grade 0 or I that occurred during the procedure. Postprocedural ST was defined as any of the following between the end of the procedure and the end of follow-up: angiographic documentation of stent occlusion, unexplained sudden death when the stent was not known to be patent, or MI or urgent target lesion revascularization occurring in the territory of LAD. Target vessel revascularization was defined as either percutaneous or surgical revascularization (CABG) of stented epicardial vessel.The secondary end point was stent thrombosis. Stent throbosis was classified based on the time elapsed since implantation. Stent thrombosis occurring during the stenting procedure or within the subsequent 24 hrs was defined as acute ST, subacute ST - between 1 and 30 days after implantation, late ST-between 1 month and 1 year, and very late ST-more than 1 year after the procedure. The definitions of MI and ST used in the study were consistent with the newest consensus of the Academic Research Consortium . All pri2 test. We used the Kaplan-Meier time-to-event estimates for the primary events at 24-month follow-up. With the Kaplan-Meier method and log-rank test, we compared the difference between the SES and the ZES cohorts. A P value < 0, 05 was considered statistically significant.All statistical analyses were performed with SPSS for Windows  and the nonparametric Mann-Whitney test (skew distribution). Analysis of categorical variables was done with Fisher’s exact test and chiBetween February 2005 and March 2008, a total of 154 patients were enrolled in the study and randomly assigned to receive ZES (80 patients) or SES (74 patients). Baseline clinical characteristics of patients were similar among the groups . In the Angiographic characteristics of patients in the two groups were also similar . The ratComparison of acute, subacute, late and very late stent thrombosis in groups were shown in The clinical characteristics of the patients at three years follow-up are reported in Percutaneous treatment has shown to improve clinical outcome in the symptomatic coronary artery disease by resolving coronary obstruction . MoreoveHowever, in the DES area, especially where restenosis is of less issue, ST is considered the Achilles’ heel of PCI . AlthougAlthough it has been shown that first-generation DESs are safe and efficacious for both on-label and off-label use when implanted in the native circulation , concernThere is compelling clinical evidence that ZES carries an extremely low risk of late ST . A prospUntil recently, the second generation DESs had proved to be significantly more effective and safe compared to the first-generation DESs in reducing the risk of ST in ACS patients owing to a better design, greater biocompatibility with release kinetic . HoweverThe results of the SORT OUT III differ from those observed in Endeavor clinical trial program in the sense that the SORTOUT III study included patients with complex lesions, such as bifurcations, ostial lesions, left main lesions, long lesions and chronic total occlusions, as well as patients with ACS and STEMI, and that it was powered to address clinical points. In the present study, MACE rate was significantly higher in the SES patients. The patients in our trial were in some features similar to those of in the SORTOUT study in that it included lesions > 2 cm, and patients with ACS and MI.We found increased rates of non-Q myocardial infarction and stent thrombosis, in the Zotarolimus-Eluting Endeavor stent as compared to the Sirolimus-Eluting Cypher stent although the rates were statistically insignificant.In the present study, we compared the first-generation sirolimus-eluting stent with the second-generation zotarolimus-eluting stent in ACS patients with C type LAD lesions, and found that the clinical and angiographic efficacy at 36 months was more in favor of the ZES group compared to that of the SES group. That result was consistent with Endeavor trials.The number of enrolled patients was relatively small.Despite the continuous double antiplatelet therapy one patient had ST in the ZES group and four in the SES group. Based on these results one might conclude that the ZES treatment of acute ischemic patients with C type LAD lesion is more effective than the SES treatment. Although dual antiplatelet therapy plays a key role in the prevention of ST, the type of DES might have an important impact on it. However, larger patient population studies are needed to clarify the statement in the above mentioned patient group.


The structural biology of co-translational protein folding on the ribosome is reviewed. Protein folding, a process that underpins cellular activity, begins co-translationally on the ribosome. During translation, a newly synthesized polypeptide chain enters the ribosomal exit tunnel and actively interacts with the ribosome elements – the r-proteins and rRNA that line the tunnel – prior to emerging into the cellular milieu. While understanding of the structure and function of the ribosome has advanced significantly, little is known about the process of folding of the emerging nascent chain (NC). Advances in cryo-electron microscopy are enabling visualization of NCs within the exit tunnel, allowing early glimpses of the interplay between the NC and the ribosome. Once it has emerged from the exit tunnel into the cytosol, the NC (still attached to its parent ribosome) can acquire a range of conformations, which can be characterized by NMR spectroscopy. Using experimental restraints within molecular-dynamics simulations, the ensemble of NC structures can be described. In order to delineate the process of co-translational protein folding, a hybrid structural biology approach is foreseeable, potentially offering a complete atomic description of protein folding as it occurs on the ribosome. The ribosome, a ribonucleoprotein macromolecular complex (ranging in size from 2.5 to 4.5 MDa), consists of two subunits that comprise ribosomal RNA  and ribosomal proteins (54 in bacteria and 80 in eukaryotes) , i.e. ribosomes harbouring NCs with variable chain lengths, which enable ‘snapshots’ of biosynthesis to be taken. Advances in cryo-EM have been instrumental in showing how certain NC sequences can interact with the PTC and exit tunnel, and arrest the elongation process . Moreover, the recent ‘resolution revolution’ in cryo-EM  and the individual subunits Fig. 2. Around Negative-stain EM structures of bacterial ribosomes were also able to differentiate distinct regions, in particular the central protuberance formed by the 5S RNA and r-proteins, the uL1 and uL12 stalk regions on the large subunit and the ‘head’, ‘body’ and ‘shoulder’ domains of the 16S rRNA within the small subunit. However, the limitations of negative-stain sample preparation resulted in flattened electron-density maps  was obtained by combining the X-ray data with intermediate-resolution EM maps, which led to the subsequent high-resolution structure  is essential for improving the understanding of antibiotic selectivity , which reveal novel ligand-binding sites that may be a means of devising novel therapies to specifically target cancerous human cells . In bacteria, the ribosomal exit tunnel is ∼100 Å in length, with an average diameter of 15 Å . The average diameter of the channel is said to be sufficient to accommodate water molecules and ions as well as to support some forms of NC structure, such as α-helices , and the lower region is formed by nucleotides from domains III and I of 23S rRNA and loops from uL23 and uL24 that line the vestibule region . As suggested by fluorescence anisotropy experiments on RNCs of the disordered protein PIR, NC interactions with the ribosomal surface can be mediated by electrostatics . Ribosome-associated proteins that act co-translationally on the NC include peptide deformylase (PDF), methionine aminopeptidase (MAP), signal recognition particle (SRP) and trigger factor (TF). The function of these factors ranges from N-terminal NC processing to assisting co-translational folding and translocation to membrane compartments. Coordination between ribosome binding and the function of these factors plays an apparent role in co-translational protein folding  have the capacity to induce translational arrest during peptidyl transfer . In the presence of abundant l-tryptophan levels in bacterial cells, the 24 residues of the TnaC peptide interact with the 23S rRNA nucleotides in the upper and central regions of the tunnel, and constriction-site loop residues such as Lys90 of L22 coordinate to l-tryptophan molecules to induce ribosome stalling . Another commonly used ribosome- stalling peptide is SecM, derived from the E. coli protein, which has also been analysed by cryo-EM . In bacteria, the SecM NC is translated downstream of the protein SecA, in which transient pausing by SecM is used to regulate the expression of SecA. SecA itself is a protein which forms part of the membrane-protein translocon machinery . It was found that flexibility of the N-terminal ErmBL NC was decreased by erythromycin and the NC made key interactions with the tunnel wall to induce stalling. It was also suggested that the antibiotic could remodel PTC, suggesting two possible modes of interaction for NCs inside the exit tunnel . The R16 NC forms several contacts with the vestibule region, which presumably assist in stabilizing the dynamic NC  and assist with its capacity to acquire structure. These emerging cryo-EM RNC structures corroborate the concept that NCs undergo folding on the ribosome.More recent cryo-EM studies of RNCs have also revealed that the ribosome can permit the formation of simple tertiary structure at the vestibule region, as exemplified by the zinc-binding ADR1α; the NC adopts its globular domain at the centre of the vestibule, ∼80 Å away from the PTC , typically preclude the formation of higher-order tertiary structure: the majority of co-translational folding for large proteins occurs beyond the vestibule region of the ribosome. The highly dynamic nascent chain beyond the exit tunnel has generally eluded both cryo-EM and X-ray crystallography, whereas its study is better suited to structural methods such as NMR spectroscopy, which relies on dynamics and offers residue-specific information. Using selective isotopic labelling of the NC, RNC NMR studies have included those of the Src homology 3 (SH3) domain  and structured conformations (13C labelling) of the NC, it was possible to describe a structural basis for co-translational folding of the FLN5 domain  are beginning to illuminate the role of the ribosome beyond protein translation, which includes the translational arrest and co-translational folding processes.Our understanding of how proteins fold in cells is taking shape owing to remarkable developments in experimental and methodological approaches. The elucidation of the structure and function of the ribosome has come a long way through key accomplishments made by biochemical and biophysical methods, complemented by high-resolution structural techniques: X-ray crystallography, cryo-EM and NMR spectroscopy. The recent progress in cryo-EM and NMR has further enabled researchers to tackle structural variations in ribosomal complexes of a dynamic nature. Near-atomic structures of many functional ribosome complexes (et al., 2017Given the described advances in preparative biochemistry, cryo-EM, NMR and computational biology, we are now placed in a good position to answer advanced questions related to the relationship between the ribosome and the folding behaviour of an emerging NC. For instance, how does the NC folding on stalled RNC systems differ from the folding of NCs in cells in real time? Does the ribosome select and stabilize certain folding intermediates over others during co-translational protein folding? What communication occurs between chaperones and the NC during co-translational folding? Are there any specific ‘triggers’ that force the NCs to fold co-translationally before complete post-translational folding? It is clear that the highly dynamic NC undergoes significant remodelling of its structure as it folds, and addressing these complex questions requires the combination of both experimental and computational approaches to study large macromolecular assemblies (Cuniasse et al., 2007X-ray crystallography can resolve atomic structures of molecules trapped in a rigid, crystallographic state, while NMR spectroscopy can provide atomic resolution information on both structure and dynamics on biological timescales. NMR studies of large molecules and complexes are however significantly complicated by the increased resonance linewidths associated with slower tumbling (Foster


We summarize the recent development of AIEgen based theranostic DDSs for the visualization of drug delivery processes. Drug delivery systems (DDSs) have been extensively studied as carriers to deliver small molecule chemo-drugs to tumors for cancer therapy. The therapeutic efficiency of chemo-drugs is crucially dependent on the effective drug concentrations in tumors and cancer cells. Novel DDSs that can simultaneously unveil drug distribution, drug release/activation behaviors and offer early evaluation of their therapeutic responses are highly desirable. Traditional fluorescent dye-labeled DDSs may suffer from notorious aggregation-caused quenching (ACQ) with limited sensitivity for bioimaging; in addition, the intrinsic fluorescence of these dyes requires careful selection of energy acceptor or quencher moieties for a light-up probe design, which complicates the development of self-reporting DDSs, especially the ones for reporting multiple processes. The recently emerged fluorogens with aggregation-induced emission characteristics (AIEgens) offer a straightforward solution to tackle this challenge. Thanks to the unique properties of AIEgens, new theranostic DDSs have been developed for simultaneous drug delivery and bioimaging with high signal to background ratio and multiple signal reporting capabilities. In this mini-review, we summarize the recent development of theranostic DDSs based on AIEgens for monitoring the drug distribution, drug activation and prediction of the therapeutic responses. Through illustration of their design principles and application examples, we hope to stimulate the interest in the design of more advanced theranostic DDSs for biomedical research. The therapeutic efficiency of chemo-drugs is crucially dependent on the effective drug concentrations in tumors and cancer cells. Upon intravenous injection of the pharmaceutically active payload, the drug will accumulate in the tumor tissue through passive or active targeting, then pass through the tumor extracellular matrix (ECM), bind to cells and cross the cell membrane to enter the targeted cancer cells. After being taken-up by cancer cells, the drug release or activation rate is crucial for therapeutic outcome. Similarly, prediction of the drug therapeutic effect is of equal importance to evaluate whether the therapeutic regimes work well, which is of great value to guide the therapeutic decisions made by doctors. Therefore, it is important to develop novel theranostic DDSs that can unveil their drug distribution, offer accurate assessment of drug release or activation in cancer cells and predict their therapeutic responses in cancer therapy. This will provide important information to further optimize the therapeutic regimes in order to advance the therapy. However, as most of the anticancer drugs are non-emissive, our capability remains limited in precisely answering when, where and how the anticancer drugs are delivered to cells. The tasks of accurate assessment of drug release or activation after cellular uptake as well as early evaluation of their therapeutic responses are even more challenging. However, the strong interest in personalized medicine calls for the development of theranostic DDSs that could provide a clear answer to all of these questions. So far, fluorescent dyes have been widely used for labeling DDSs to study their biodistribution. After their accumulation in tumor sites and being taken-up by cancer cells, the drug activation process was monitored in vitro and in vivo, particularly for anticancer drugs conjugated with fluorogenic dyes through tumor microenvironment responsive linkers. Recently, real-time monitoring of the therapeutic responses has been realized by imaging the drug induced cancer cell apoptosis, a pathway commonly involved in cell death. The majority of theranostic DDSs relies on fluorescent dyes with aggregation-caused quenching (ACQ) to report the signal, which limits the detection sensitivity. In addition, the intrinsic fluorescence of most dyes requires careful selection of energy acceptors or quencher moieties to realize fluorescence change, which complicates the design of self-reporting DDSs, especially the ones for reporting multiple processes.Drug delivery systems (DDSs) have been extensively studied as carriers to deliver small molecule chemo-drugs to tumors for cancer therapy. Opposite to the photophysical phenomenon of ACQ dyes, AIEgens are almost non-emissive in the molecularly dissolved state but emit intensely in the aggregated state due to the restriction of intramolecular motions and prohibition of energy dissipation via non-radiative decay channels. Tetraphenylethene (TPE), an iconic AIEgen, is of particular research interest. The central olefin stator of the TPE molecule is surrounded by four phenyl rings. As shown in  The unique features of various AIEgens with tunable absorption and emission colors have led to the development of simple light-up probes and very bright AIE nanoparticles, making them promising tools for biomedical applications.The discovery of a novel class of fluorogens with aggregation-induced emission characteristics (AIEgens) has recently received intense research interest in biosensing and bioimaging because AIEgens offer a straightforward solution to the ACQ problem.In this review, we summarize the recent development of AIEgen based theranostic DDSs for the visualization of drug delivery processes . The rev However, these methods may suffer from some problems, such as fluorescence quenching associated poor imaging sensitivity of fluorescent dyes or the potential toxicity of quantum dots. Therefore, it is highly desirable to develop biocompatible self-luminescent DDSs for real-time monitoring of the drug distribution upon intravenous injection. Inspired by the unique properties of AIEgens that are highly fluorescent in the aggregated state, several AIEgen based theranostic DDSs have been developed recently to monitor the drug distribution with promising results.To monitor the drug distribution of DDSs upon intravenous injection and internalization into selected cancer cells, the commonly used strategy is to label the DDSs through encapsulation/conjugation with fluorescent dyes or quantum dots.et al. developed a traceable DDS using TPE derivatives to fabricate self-assembled micelles to visualize the intracellular drug distribution. In this work, a hydrophilic and biocompatible polymer, polyethylene glycol (PEG), is conjugated to TPE to form an amphiphilic AIE polymer (TPE–mPEG), which can self-assemble into micelles in aqueous solution and allow efficient loading of anticancer drug doxorubicin (DOX)  . The criet al. developed two pH-responsive amphiphilic polymers based on TPE to monitor the intracellular distribution and drug release ( These amphiphilic polymers (TPE–hydrazone–mPEG and dextran–hydrazone–mPEG) self-assembled into micelles with the encapsulation of DOX, which exhibited blue fluorescence of TPE in aqueous media. The DDSs were located in endo/lysosomes after cellular uptake, which were revealed by the colocalization of the blue fluorescence of TPE and lysotracker green as an endo/lysosome specific fluorescent tracker. Moreover, the DOX showed pH-regulated release behavior and the released drug in acidic endo/lysosomal could be imaged by the fluorescence increase of TPE due to the cleavage of the hydrazone bond, which terminated the energy transfer between TPE and DOX to recover the quenched TPE fluorescence. In addition, in vitro results demonstrated that both of the drug-loaded nanoparticles exhibited dose-dependent cytotoxicity to HeLa cells. Recently, Liu et al. also developed a light-responsive amphiphilic AIE polymer for drug delivery (AIE-NPs/DOX) and imaging the cytosolic drug release to overcome drug resistance in cancer cells  of AIE-NPs/DOX with light irradiation is ∼12% of free DOX and ∼32% under dark conditions after 72 h incubation.Later on, Wang  release .26,27 er cells .28 In et al. developed a self-indicating DDS based on fluorescence resonance energy transfer (FRET) between TPE and DOX for spatiotemporal visualization of the drug distribution and release. The self-luminescent TPE nanoparticles (TPE NPs) can easily bond with DOX to form TPE–DOX NPs via electrostatic interactions in aqueous solution  sensitive nanoparticles (S-NPs) for light controlled gene delivery ( This polymer consists of oligoethylenimine (OEI) and an AIE photosensitizer (TPECM) conjugated through a ROS reactive aminoacrylate linker. The polymer can self-assemble into S-NPs and bind with DNA to show bright red fluorescence. Once the DNA is intercalated with YOYO-1, the S-NPs/DNA complexes have a yellow emission, which can be used for tracking the gene delivery. After cellular uptake, yellow fluorescence was observed in the endo/lysosomes, indicating the initial location of the genes in the cells  complexes are usually used as a prodrug which can be intracellularly reduced to the active Pt(ii) complex to restore their latent cytotoxic activity. To capture the dynamic Pt(iv) prodrug activation, Liu and Tang et al. synthesized and evaluated a targeted theranostic platinum(iv) prodrug delivery system ( Cyclic arginine–glycine–aspartic acid (cRGD) and five units of aspartic acid (D) were inserted between Pt(iv) and the AIEgens to endow the probe with targeting ability and good water-solubility. As shown in iv) was reduced intracellularly to yield the toxic Pt(ii) drug and generated a highly emissive AIE residue. The light-up fluorescence provides a reliable signal for quantitative analysis of the active drug concentration with high signal-to-noise ratio. As expected, the prodrug shows more potent cancer cell inhibition to MDA-MB-231 cells as compared with MCF-7 cells with low integrin expression.Apart from DOX, cisplatin is another chemo-drug which has been extensively used in clinics to treat a broad spectrum of human cancers, but it suffers from severe side effects which limit its clinical use. To overcome these limitations, its nontoxic form as Pt prodrug was functionalized with blue-emissive TPE as an energy donor and a red emissive anticancer drug DOX as the energy acceptor. Before drug activation, the fluorescence of TPE is quenched due to energy transfer to DOX, while red fluorescence of DOX upon direct excitation at 488 nm can be utilized for the prodrug intracellular distribution monitoring. After cellular uptake, the prodrug was first located in endo/lysosome with red fluorescence. Concomitant with the drug activation, the separation between TPE and DOX resulted in fluorescence recovery of the blue emissive TPE and its fluorescence was intensified within 2 h, indicative of drug activation for both Pt(ii) and DOX. This is further evidenced by the red fluorescence of DOX observed at 6 h in the nuclei. The simultaneous DOX and cisplatin activation resulted in synergistic anticancer effects. The IC50 of cRGD–TPE–Pt–DOX against MDA-MB-231 cells is 0.69 mM, which is 2.3 and 26.6 times lower than those of DOX (IC50 = 1.6 mM) and cisplatin (IC50 = 18.1 mM) treatments, respectively. Such a dual-acting theranostic DDS with prodrug tracking, real-time drug activation monitoring and synergistic anticancer effects is beneficial for cancer therapy.Later, the same research group further designed and constructed a traceable targeted theranostic DDS containing two prodrugs for dual-drug tracking with synergistic anticancer effects. Kim et al. developed a mitochondria targeted prodrug TPP–TPE–NQO1, which is composed of a TPE derivative conjugated with an NAD(P)H:quinone oxidoreductase-1 (NQ-1) cleavable masking unit with a mitochondria targeting triphenylphosphine (TPP) moiety. The non-fluorescent TPP–TPE–NQO1 showed preferential accumulation in cancer cells and underwent rapid reduction of the quinone scaffold in the presence of NQ-1, resulting in cyclisation, which releases the active form of the TPE derivative synchronously with strong blue fluorescence turn-on. The released AIEgen can specifically target mitochondria and induce the disruption of major metabolic pathways. As shown in in vivo and ex vivo studies. The work confirmed that the therapeutic effect was dependent on both the sub-organelle localization and specific in situ prodrug activation.DDSs that target sub-organelle combined with tumor microenvironment associated enzymatic drug activation can enhance the selectivity of cancer therapy. The mitochondrion is one of the most vital subcellular organelles which is known as the powerhouse of both normal and malignant cells. The combination of microenvironment associated enzymatic drug activation and the subsequent mitochondria targeting can induce the disruption of major metabolic pathways in mitochondria to lead to effective cancer cell death. PDT requires a PS to generate cytotoxic reactive oxygen species (ROS) upon light irradiation to induce cell death. Recently, some AIEgens were engineered to show therapeutic effects. Unlike conventional porphyrin based PSs, AIEgen PSs do not suffer from quenched fluorescence or obviously reduced photosensitizing efficiency in the aggregate state. Recently, Zhang and Yang et al. developed a red emissive probe TPEr–2AP2H containing a TPE derived PS and two peptides that could specifically target tumor overexpressed biomarker LAPTM4B proteins  scale" fill="currentColor" stroke="none"><path d="M0 1440 l0 -80 1360 0 1360 0 0 80 0 80 -1360 0 -1360 0 0 -80z M0 960 l0 -80 1360 0 1360 0 0 80 0 80 -1360 0 -1360 0 0 -80z"/></g></svg>C(CN)2] moiety to the TPE core endowed the AIEgens with photosensitivity for ROS generation. As shown in in situ fluorescence turn-on to monitor the PS activation. The selective cancer cell ablation with fluorescence-guided light irradiation is shown in et al. developed a dual targeted theranostic probe based on TPECM with activatable PDT for targeted cancer cell ablation. The probe contains a cRGD peptide to target integrins overexpressed on the cancer cell surface with a second peptide sequence to respond to cathepsin B enzymes overexpressed in cancer cell lysosomes. The probe is non-fluorescent by itself. Once it is trapped in a lysosome, cathepsin B cleaves the probe, and releases the hydrophobic TPECM residues to generate red fluorescence. This indicated the activation of the photosensitization properties of TPECM, which was subsequently used for image-guided PDT. The dual-targeted design strategy enables light-up cancer-cell imaging with a high signal-to-noise ratio and led to highly selective ablation of MDA-MB-231 cancer cells with minimum toxicity to 293T normal cells under the same experimental conditions. This probe design offers a good opportunity to develop activatable PSs without incorporating any quencher or energy acceptor, which can also achieve enhanced fluorescence and phototoxicity in the aggregate state upon activation by tumor related stimuli.Apart from the various therapeutic drugs for cancer therapy, photosensitizer (PS) drugs as an emerging therapeutic agent have received increasing attention as photodynamic therapy (PDT) can be spatiotemporally controlled with light irradiation.proteins .48 The it remains a challenge to in situ monitor ROS generation in living systems due to the extremely small radius of action (<20 nm) and short lifetime (<40 ns) of ROS. To tackle this issue, Liu et al. developed a probe which is composed of an AIEgen photosensitizer conjugated with a fluorogenic green emissive rhodol dye through a ROS cleavable aminoacrylate linker  into prodrugs or nanoparticles, in situ monitoring of the drug therapeutic effects has also been realized. In addition, some of the theranostic DDSs based on AIEgens have also been developed for real-time monitoring of the therapeutic responses which are discussed in this section.Although the above probes can monitor drug distribution and drug activation in cancer cells, they do not offer any information on the drug therapeutic responses. To monitor the therapeutic responses of a specific DDS is of high importance for clinical applications as it can guide the therapeutic decisions to evaluate the therapeutic regimes. The current clinical method to evaluate the therapeutic effect of cancer treatment is to measure the tumor size change using a magnetic resonance imaging (MRI) study. It is known that most anticancer drugs kill cancer cells through an apoptosis pathway by activating caspase enzymes within a short period of time. Therefore, the accurate detection of caspase enzyme activation in cells could be a reliable strategy to predict the therapeutic response of drugs at a very early stage. Recently, we have developed several light-up fluorescent probes based on AIEgens for real-time monitoring of cell apoptosis via the detection of caspase enzyme activation. Although these probes can monitor drug induced cell apoptosis, they are not able to quantify the therapeutic responses of drugs in real-time and in situ as the distribution or subcellular location of drugs and probes may not be the same.Apoptosis, or programmed cell death, is an important and active regulatory pathway of cell growth and proliferation.et al. developed a targeted theranostic platinum(iv) prodrug delivery system TPS–DEVD–Pt–cRGD for drug delivery to targeted cancer cells and simultaneous non-invasive early evaluation of the therapeutic response of an activated drug in situ ( Cisplatin was modified to the nontoxic form of the platinum(iv) prodrug and its two axial positions were functionalized with a targeting peptide cRGD and a built-in AIE light-up apoptosis sensor TPS–DEVD, which is composed of tetraphenylsilole (TPS) and a caspase-3 enzyme specific Asp-Glu-Val-Asp (DEVD) peptide. After cellular uptake by αvβ3 integrin overexpressed cancer cells, the Pt(iv) prodrug was reduced to form an active Pt(ii) drug and simultaneously release TPS–DEVD. The toxic Pt(ii) further induces the cell apoptosis and activates caspase-3 enzyme, which can be specifically detected by TPS–DEVD with TPS fluorescence light-up. To solve this problem, Liu and Tang  in situ .54 Cisin situ monitoring of the therapeutic response, the same group further developed a multifunctional theranostic DDS, which is composed of an AIEgen photosensitizer with red-emission and a built-in green emissive activatable AIE light-up apoptosis sensor for targeted PDT and real-time monitoring of drug activation and prediction of the therapeutic response  with ACQ properties and a green emissive TPS with AIE characteristics for tracing the whole process of PDT . This calls for the development of next generation AIEgens with fluorogenic properties, such as those with excited state intramolecular proton transfer (ESIPT) properties to bypass the background issues associated with the probe solubility. Secondly, the theranostic DDSs covered in this review mainly used AIEgens with absorption in the blue and green regions, which are not very suitable for