An engineered enzyme embedded into PLA to make self-biodegradable plastic.

Plastic production reached 400 million tons in 2022 (ref. 1), with packaging and single-use plastics accounting for a substantial amount of this2. The resulting waste ends up in landfills, incineration or the environment, contributing to environmental pollution3. Shifting to biodegradable and compostable plastics is increasingly being considered as an efficient waste-management alternative4. Although polylactide (PLA) is the most widely used biosourced polymer5, its biodegradation rate under home-compost and soil conditions remains low6-8. Here we present a PLA-based plastic in which an optimized enzyme is embedded to ensure rapid biodegradation and compostability at room temperature, using a scalable industrial process. First, an 80-fold activity enhancement was achieved through structure-based rational engineering of a new hyperthermostable PLA hydrolase. Second, the enzyme was uniformly dispersed within the PLA matrix by means of a masterbatch-based melt extrusion process. The liquid enzyme formulation was incorporated in polycaprolactone, a low-melting-temperature polymer, through melt extrusion at 70 °C, forming an 'enzymated' polycaprolactone masterbatch. Masterbatch pellets were integrated into PLA by melt extrusion at 160 °C, producing an enzymated PLA film (0.02% w/w enzyme) that fully disintegrated under home-compost conditions within 20-24 weeks, meeting home-composting standards. The mechanical and degradation properties of the enzymated film were compatible with industrial packaging applications, and they remained intact during long-term storage. This innovative material not only opens new avenues for composters and biomethane production but also provides a feasible industrial solution for PLA degradation.

[The false aneurysm of the left ventricle complicating mitral valvular surgery]. / Faux anévrysme du ventricule gauche compliquant un remplacement valvulaire mitral.

The false aneurysm of the left ventricle is a rare complication after a mitral valvular surgery. It results from the rupture of the ventricular wall inside an adhering pericardium, thus constituting a cavity whose wall is devoid of myocardial elements and communicates with the ventricle by a large collar. Its clinical presentation remains not very specific with an insidious spontaneous evolution which is generally done towards rupture with sudden death by tamponade. Various sophisticated modern diagnostic techniques allows a precise diagnosis. The letal nature of this lesion must be recognized and justifies an immediate surgical repair. We report the case of a 68 years old patient who presented herself in consultation of cardiology with a NYHA IIb (New York Heart Association) cardiac failure 4 months after a surgery of mitral valvular replacement. The transthoracic echography showed a voluminous false aneurysm of the left ventricle confirmed by cardiac CT scan. She has benefited from an anevrismectomy with good clinic evolution. This observation illustrates the late and silent character of the development of the false aneurysm of the left ventricle after mitral valvular surgery.

Le faux anévrysme du ventricule gauche est une complication rare après chirurgie valvulaire mitrale1. Il résulte de la rupture de la paroi du ventricule dans le péricarde adhérant, constituant ainsi une cavité dont le mur est dépourvu d'éléments myocardiques et qui communique avec le ventricule par un large collet. Sa présentation clinique reste peu spécifique avec une évolution spontanée insidieuse qui se fait le plus souvent vers la rupture avec mort subite par tamponnade1,2. Diverses techniques diagnostiques modernes permettent un diagnostic précis. La nature potentiellement létale de cette lésion doit être reconnue et justifie une réparation chirurgicale immédiate. Nous rapportons le cas d'une patiente âgée de 68 ans qui s'est présentée en consultation de cardiologie avec un tableau d'insuffisance cardiaque gauche stade IIB selon la New York Heart Association (NYHA) 4 mois après une chirurgie de remplacement valvulaire mitral. L'échographie transthoracique a montré un volumineux faux anévrysme de la paroi inférolatérale du ventricule gauche, confirmé par le scanner cardiaque. Elle a bénéficié d'une anévrysmectomie avec bonne évolution clinique. Cette observation illustre le caractère tardif et parfois silencieux du développement du faux anévrysme du ventricule gauche après chirurgie valvulaire mitrale.

Effects of oxygen on responses to heating in two lizard species sampled along an elevational gradient.

Thermal tolerance is an important variable in predictive models about the effects of global climate change on species distributions, yet the physiological mechanisms responsible for reduced performance at high temperatures in air-breathing vertebrates are not clear. We conducted an experiment to examine how oxygen affects three variables exhibited by ectotherms as they heat-gaping threshold, panting threshold, and loss of righting response (the latter indicating the critical thermal maximum)-in two lizard species along an elevational (and therefore environmental oxygen partial pressure) gradient. Oxygen partial pressure did not impact these variables in either species. We also exposed lizards at each elevation to severely hypoxic gas to evaluate their responses to hypoxia. Severely low oxygen partial pressure treatments significantly reduced the gaping threshold, panting threshold, and critical thermal maximum. Further, under these extreme hypoxic conditions, these variables were strongly and positively related to partial pressure of oxygen. In an elevation where both species overlapped, the thermal tolerance of the high elevation species was less affected by hypoxia than that of the low elevation species, suggesting the high elevation species may be adapted to lower oxygen partial pressures. In the high elevation species, female lizards had higher thermal tolerance than males. Our data suggest that oxygen impacts the thermal tolerance of lizards, but only under severely hypoxic conditions, possibly as a result of hypoxia-induced anapyrexia.

[Stroke : don't forget the aorta!] / AVC : n'oubliez pas l'aorte !

We are presenting a particular case of stroke occurring in a 45-years old woman.

Nous présentons un cas particulier d'accident vasculaire cérébral survenu chez une patiente de 45 ans.

Oxygen concentration affects upper thermal tolerance in a terrestrial vertebrate.

We tested the oxygen limitation hypothesis, which states that animals decline in performance and reach the upper limits of their thermal tolerance when the metabolic demand for oxygen at high temperatures exceeds the circulatory system's ability to supply adequate oxygen, in air-breathing lizards exposed to air with different oxygen concentrations. Lizards exposed to hypoxic air (6% O2) gaped, panted, and lost their righting response at significantly lower temperatures than lizards exposed to normoxic (21% O2) or hyperoxic (35% O2) air. A greater proportion of lizards in the hyperoxic treatment were able to withstand body temperatures above 44°C than in the normoxic treatment. We also found that female lizards had a higher panting threshold than male lizards, while sex had no effect on gaping threshold and loss of righting response. Body size affected the temperature at which lizards lost the righting response, with larger lizards losing the response at lower temperatures than smaller lizards when exposed to hypoxic conditions. These data suggest that oxygen limitation plays a mechanistic role in the thermal tolerance of lizards.

Simulation of normal pelvic mobilities in building an MRI-validated biomechanical model.

INTRODUCTION AND HYPOTHESIS: Three-dimensional modeling of feminine pelvic mobility is difficult because the sustaining system is not well understood and ligaments are especially difficult to identify on imaging. METHODS: We built a 3-D numerical model of the pelvic cavity, based on magnetic resonance (MR) images and knowledge about anatomy and validated it systematically. RESULTS: The quantitative results of this model allow for the non-destructive localization of the structures involved in pelvic statics. With a better configuration of the functional pelvis and topological criteria, we can obtain a coherent anatomical and functional model. CONCLUSIONS: This model is the first step in developing a tool to localize and characterize pelvic imbalance in patients.

North Sea ecosystem change from swimming crabs to seagulls.

A recent increase in sea temperature has established a new ecosystem dynamic regime in the North Sea. Climate-induced changes in decapods have played an important role. Here, we reveal a coincident increase in the abundance of swimming crabs and lesser black-backed gull colonies in the North Sea, both in time and in space. Swimming crabs are an important food source for lesser black-backed gulls during the breeding season. Inhabiting the land, but feeding mainly at sea, lesser black-backed gulls provide a link between marine and terrestrial ecosystems, since the bottom-up influence of allochthonous nutrient input from seabirds to coastal soils can structure the terrestrial food web. We, therefore, suggest that climate-driven changes in trophic interactions in the marine food web may also have ensuing ramifications for the coastal ecology of the North Sea.

Early and late parameters describing the offset of neuromuscular blockade are highly intercorrelated.

BACKGROUND: Neuromuscular blocking agents have always shown wide inter-individual variability when it comes to their duration of action. This prevents clinicians from anticipating the evolution of the neuromuscular block for any given patient. With this study, we aimed to assess the nature of the relationships existing between different time course parameters used to describe paralysis onset and offset. METHODS: Sixty American Society of Anesthesiologists (ASA) score III-IV anaesthetised patients were randomised to receive a single equipotent dose (2ED95) of either rocuronium, mivacurium or atracurium. We used acceleromyography to monitor neuromuscular transmission. We described the relationships between the time-interval measurements of: onset, the first response (T1) reappearance, T1 25% of control, train-of-four ratio 0.25 and 0.75. Pearson correlation coefficients were calculated. RESULTS: We found no significant relationships between onset and any of the four parameters used to describe the offset. On the other hand, we showed strong and highly significant linear relationships between all the parameters describing the offset for each of the muscle relaxants studied (correlation coefficients ranging from 0.850 to 0.992). CONCLUSIONS: We evidenced strong linear correlations between the four offset time course parameters of spontaneous recovery after a single neuromuscular blocking agents (NMBAs) bolus. Such relationships open up new clinical perspectives concerning quantitative neuromuscular transmission monitoring: the scope of individual valuable anticipation of the patient's recovery.

Body size impacts critical thermal maximum measurements in lizards.

Understanding the mechanisms behind critical thermal maxima (CTmax; the high body temperature at which neuromuscular coordination is lost) of organisms is central to understanding ectotherm thermal tolerance. Body size is an often overlooked variable that may affect interpretation of CTmax, and consequently, how CTmax is used to evaluate mechanistic hypotheses of thermal tolerance. We tested the hypothesis that body size affects CTmax and its interpretation in two experimental contexts. First, in four Sceloporus species, we examined how inter- and intraspecific variation in body size affected CTmax at normoxic and experimentally induced hypoxic conditions, and cloacal heating rate under normoxic conditions. Negative relationships between body size and CTmax were exaggerated in larger species, and hypoxia-related reductions in CTmax were unaffected by body size. Smaller individuals had faster cloacal heating rates and higher CTmax, and variation in cloacal heating rate affected CTmax in the largest species. Second, we examined how body size interacted with the location of body temperature measurements (i.e., cloaca vs. brain) in Sceloporus occidentalis, then compared this in living and deceased lizards. Brain temperatures were consistently lower than cloacal temperatures. Smaller lizards had larger brain-cloacal temperature differences than larger lizards, due to a slower cloacal heating rate in large lizards. Both live and dead lizards had lower brain than cloacal temperatures, suggesting living lizards do not actively maintain lower brain temperatures when they cannot pant. Thermal inertia influences CTmax data in complex ways, and body size should therefore be considered in studies involving CTmax data on species with variable sizes.

Structure, composition and mechanical relations to function in sea urchin spine.

Sea urchins have characteristic spines that fulfil critical functions. Several studies revealed marked spine internal heterogeneities at different structural levels despite the single-crystal character of the spines. Most of these studies did not speculate about the functional meaning of these heterogeneities. Spine heterogeneities were investigated in the sea urchin Paracentrotuslividus and their possible functional implications discussed. Spines mainly show two morphological parts: the base, made of a meshwork stereom, and the shaft, with longitudinal plain septa and a central core of meshwork stereom. Electron Backscatter Diffraction showed no difference in crystallite orientation between the two structures. Atomic Absorption Spectrometry and Energy dispersive X-ray analysis revealed that Mg was not uniformly distributed in the spine. Mg concentration is higher in the inner part of the septa than in the septum outer part. Furthermore, a cyclic pattern of Mg concentration in septa was observed. This is suggested to be linked to the spine ontogeny. Nano- and microindentation analyses revealed that the septa have higher stiffness and hardness than the meshwork stereom and that septum stiffness and hardness present different trends in longitudinal and transverse section. These mechanical heterogeneities may have an adaptive functional value.

Resting memory CD8+ T cells are hyperreactive to antigenic challenge in vitro.

The characteristics of CD8+ T cells responsible for memory responses are still largely unknown. Particularly, it has not been determined whether different activation thresholds distinguish naive from memory CD8+ T cell populations. In most experimental systems, heterogeneous populations of primed CD8+ T cells can be identified in vivo after immunization. These cells differ in terms of cell cycle status, surface phenotype, and/or effector function. This heterogeneity has made it difficult to assess the activation threshold and the relative role of these subpopulations in memory responses. In this study we have used F5 T cell receptor transgenic mice to generate a homogeneous population of primed CD8+ T cells. In the F5 transgenic mice, peptide injection in vivo leads to activation of most peripheral CD8+ T cells. In vivo BrdU labeling has been used to follow primed T cells over time periods spanning several weeks after peptide immunization. Our results show that the majority of primed CD8+ T cells generated in this system are not cycling and express increased levels of CD44 and Ly6C. These cells remain responsive to secondary peptide challenge in vivo as evidenced by short term upregulation of activation markers such as CD69 and CD44. The activation thresholds of naive and primed CD8+ T cells were compared in vitro. We found that CD8+ T cells from primed mice are activated by peptide concentrations 10-50-fold lower than naive mice. In addition, the kinetics of interleukin 2R alpha chain upregulation by primed CD8+ T cells differ from naive CD8+ T cells. These primed hyperresponsive CD8+ T cells might play an important role in the memory response.

Transfer dynamics of macroplastics in estuaries - New insights from the Seine estuary: Part 2. Short-term dynamics based on GPS-trackers.

The dynamics of plastic debris were assessed in the Seine River, especially in the estuary, using plastic bottles equipped with GPS-trackers. In one year, 50 trajectories were recorded, covering a wide range of hydrometeorological conditions. Results show a succession of stranding/remobilization episodes in combination with alternating upstream and downstream transport in the estuary. In the end, 100% of the tracked bottles stranded somewhere, for hours or weeks, from one to several times at different sites. The overall picture shows that different physical phenomena interact with various time scales ranging from hours/days (high/low tides) to weeks/months (spring/neap tides and highest tides) and years (seasonal river flow). Thus, the fate of plastic debris is highly unpredictable, but the consequence of those interactions is that the transfer of debris is chaotic and not straightforward, and its residence time is much longer than the transit time of water.

Differentiation of a teratocarcinoma line: preferential development of cholinergic neurons.

A line of embryonal carcinoma cells, PCC7-S, established in vitro from a spontaneous testicular teratocarcinoma, has been studied. Upon removing the cells from a low density monolayer culture system and permitting the cells to form aggregates in suspension, we observed a change of several physical and biochemical parameters: (a) reduction in average cell volume, (b) blockage and accumulation of cells in G1, (c) rise in secreted protease activity, (d) rise in acetylcholinesterase and choline acetyltransferase activities, and (e) disappearance of embryonic antigen F9. Although PCC7 aggregates did not undergo substantial morphological changes while suspended, when aggregates 4 or more days old were allowed to attach to plastic tissue culture dishes, substantial neurite outgrowth occurred over the next 1-3 d. This process was markedly enhanced by the addition to the growth medium of carboxymethylcellulose and inhibitors of DNA synthesis. Transmission electron microscopy disclosed a neurite ultrastructure consistent with that of neuronal processes. A veratridine-stimulated, tetrodotoxin-blocked sodium influx of 100 nmol/min per mg protein was also observed in these differentiated surface cultures. This cell line is discussed in terms of its utility for the study of early events leading to a commitment to cellular differentiation, as well as for the investigation of terminal differentiation to cholinergic neurons.

Induction of pituitary lactotrope differentiation by luteinizing hormone alpha subunit.

Addition of gonadotropin releasing hormone to cultures of fetal rat pituitary induced differentiation of lactotropes as revealed by immunocytochemistry. Antiserum to luteinizing hormone (LH) (recognizing native LH), but not antiserum to LH-beta (recognizing both native LH and its beta subunit), inhibited this induction. Further addition of highly purified LH-alpha subunit in culture medium also induced lactotrope differentiation. Thus, the alpha subunit may have a specific biological activity of its own with probable practical use in clinical investigations.

The rationale of opportunistic bilateral salpingectomies (OBS) during benign gynaecological and obstetric surgery: a consensus text of the Flemish Society of Obstetrics and Gynaecology (VVOG).

Ovarian cancer (OC), is a disease difficult to diagnose in an early stage implicating a poor prognosis. The 5-year overall survival in Belgium has not changed in the last 18 years and remains 44 %. There is no effective screening method (secondary prevention) to detect ovarian cancer at an early stage. Primary prevention of ovarian cancer came in the picture through the paradigm shift that the fallopian tube is often the origin of ovarian cancer and not the ovary itself. Opportunistic bilateral salpingectomy (OBS) during benign gynaecological and obstetric surgery might have the potential to reduce the risk of ovarian cancer by as much as 65 %. Bilateral risk-reducing salpingectomy during a benign procedure is feasible, safe, appears to have no impact on the ovarian function and seems to be cost effective. The key question is whether we should wait for a RCT or implement OBS directly in our daily practice. Guidelines regarding OBS within our societies are therefore urgently needed. Our recommendation is to inform all women without a child wish, undergoing a benign gynaecological or obstetrical surgical procedure about the pro's and the con's of OBS and advise a bilateral salpingectomy. Furthermore, there is an urgent need for a prospective registry of OBS. The present article is the consensus text of the Flemish Society of Obstetrics and Gynaecology (VVOG) regarding OBS.

Organic synthesis in soft wall-free microreactors: real-time monitoring of fluorogenic reactions.

A new approach of "laboratory on a chip" (LOC) devoted to organic synthesis based on electrically operated ionic liquid microdroplets used as air-stable "soft" microreactors was recently introduced. A number of challenging issues have yet to be addressed to allow standard macroscale organic chemistry to be directly transposed in these nonclassical microreactors. In particular, since standard (i.e., magnetical or mechanical) stirring methods are prohibited in such wall-free microreactors, effective alternatives have to be developed to circumvent mass-transfer limitations. With this aim in mind, a fluorogenic version of a click chemistry reaction was developed to evaluate the efficiency of alternative mixing methods on the reaction kinetics. We demonstrate that the combination of chaotic advection created by surface acoustic waves combined with a temperature increase (Marangoni effect) leads to the same kinetics regime as in standard macroscale conditions. This opens the route for application of the new generation of LOC to efficient organic synthesis in microscale.

Translational mini-review series on the immunogenetics of gut disease: immunogenetics of coeliac disease.

Recent advances in immunological and genetic research in coeliac disease provide new and complementary insights into the immune response driving this chronic intestinal inflammatory disorder. Both approaches confirm the central importance of T cell-mediated immune responses to disease pathogenesis and have further begun to highlight other relevant components of the mucosal immune system, including innate immunity and the control of lymphocyte trafficking to the mucosa. In the last year, the first genome wide association study in celiac disease led to the identification of multiple new risk variants. These risk regions implicate genes involved in the immune system. Overlap with autoimmune diseases is striking with several of these regions being shown to confer susceptibility to other chronic immune-mediated diseases, particularly type 1 diabetes.

Novel method of doxorubicin-SPION reversible association for magnetic drug targeting.

A new method of reversible association of doxorubicin (DOX) to superparamagnetic iron oxide nanoparticles (SPION) is developed for magnetically targeted chemotherapy. The efficacy of this approach is evaluated in terms of drug loading, delivery kinetics and cytotoxicity in vitro. Aqueous suspensions of SPION (ferrofluids) were prepared by coprecipitation of ferric and ferrous chlorides in alkaline medium followed by surface oxidation by ferric nitrate and surface treatment with citrate ions. The ferrofluids were loaded with DOX using a pre-formed DOX-Fe(2+) complex. The resulting drug loading was as high as 14% (w/w). This value exceeds the maximal loading known from literature up today. The release of DOX from the nanoparticles is strongly pH-dependent: at pH 7.4 the amount of drug released attains a plateau of approximately 85% after 1h, whereas at pH 4.0 the release is almost immediate. At both pH, the released drug is iron-free. The in vitro cytotoxicity of the DOX-loaded SPION on the MCF-7 breast cancer cell line is similar to that of DOX in solution or even higher, at low-drug concentrations. The present study demonstrates the potential of the novel method of pH-sensitive DOX-SPION association to design novel magnetic nanovectors for chemotherapy.