Facial Allograft Donation: An Interpretative Phenomenological Analysis of the Experiences of Family Members.

Facial allograft transplantation can be regarded as a particular and complex type of donation because of its perceptibility and the importance of the face as an identity characteristic. As research on this topic is currently lacking, the objective of this study is to explore the experiences of the family members of the donor in facial allograft donation. In-depth, semi-structured interviews were conducted separately with the donor's family members and analyzed using interpretative phenomenological analysis. Six themes were identified: (1) Contrasting facial donation to that of more commonly donated organs; (2) Consenting to facial donation; (3) Expectations towards the recipient of the facial graft; (4) Expectations and consequences of restoration of the donor's face; (5) Relationship with the medical team during the process; and (6) Media attention. The findings of our study help to better support donor families through the facial donation process and to improve facial transplantation procedures.

Bacterial origins of thymidylate metabolism in Asgard archaea and Eukarya.

Asgard archaea include the closest known archaeal relatives of eukaryotes. Here, we investigate the evolution and function of Asgard thymidylate synthases and other folate-dependent enzymes required for the biosynthesis of DNA, RNA, amino acids and vitamins, as well as syntrophic amino acid utilization. Phylogenies of Asgard folate-dependent enzymes are consistent with their horizontal transmission from various bacterial groups. We experimentally validate the functionality of thymidylate synthase ThyX of the cultured 'Candidatus Prometheoarchaeum syntrophicum'. The enzyme efficiently uses bacterial-like folates and is inhibited by mycobacterial ThyX inhibitors, even though the majority of experimentally tested archaea are known to use carbon carriers distinct from bacterial folates. Our phylogenetic analyses suggest that the eukaryotic thymidylate synthase, required for de novo DNA synthesis, is not closely related to archaeal enzymes and might have been transferred from bacteria to protoeukaryotes during eukaryogenesis. Altogether, our study suggests that the capacity of eukaryotic cells to duplicate their genetic material is a sum of archaeal (replisome) and bacterial (thymidylate synthase) characteristics. We also propose that recent prevalent lateral gene transfer from bacteria has markedly shaped the metabolism of Asgard archaea.

Synthesis and Structure-Activity Relationship Studies of Pyrido [1,2-e]Purine-2,4(1H,3H)-Dione Derivatives Targeting Flavin-Dependent Thymidylate Synthase in Mycobacterium tuberculosis.

In 2002, a new class of thymidylate synthase (TS) involved in the de novo synthesis of dTMP named Flavin-Dependent Thymidylate Synthase (FDTS) encoded by the thyX gene was discovered; FDTS is present only in 30% of prokaryote pathogens and not in human pathogens, which makes it an attractive target for the development of new antibacterial agents, especially against multi-resistant pathogens. We report herein the synthesis and structure-activity relationship of a novel series of hitherto unknown pyrido[1,2-e]purine-2,4(1H,3H)-dione analogues. Several synthetics efforts were done to optimize regioselective N1-alkylation through organopalladium cross-coupling. Modelling of potential hits were performed to generate a model of interaction into the active pocket of FDTS to understand and guide further synthetic modification. All those compounds were evaluated on an in-house in vitro NADPH oxidase assays screening as well as against Mycobacterium tuberculosis ThyX. The highest inhibition was obtained for compound 23a with 84.3% at 200 µM without significant cytotoxicity (CC50 > 100 µM) on PBM cells.

Water and ion diffusion in partially-water saturated compacted kaolinite: Role played by vapor-phase diffusion in water mobility.

Diffusion is the main transport process of water and solutes in clay-rich porous media owing to their very low permeability, so they are widely used as barriers against contaminant spreading. However, the prediction of contaminant mobility can be very complicated when these media are partially water-saturated. We conducted diffusion experiments for water (HTO and HDO) and ions (22Na+ and 125I-) through partially water saturated compacted kaolinite, a weakly charged clay material, to quantify the distinct diffusive behavior of these species. The osmosis method was used to set kaolinite samples at 67, 86 and 100% saturation. The results showed that desaturation led to a sharp decrease in diffusive rates by factors of 6.5, 18 and 35 for HTO, 125I- and 22Na+, respectively, from 100 to 67% of the degree of saturation. Thus, to interpret water diffusivities, we proposed a model taking into account the diffusion of water in both gas and liquid phases, using diffusion data obtained for ions, considered as inert species. This model was capable of properly predicting water diffusive flux, especially at a low degree of saturation (67% saturation), for which the assumption made for the occurrence of air phase continuity throughout the sample appears to be more relevant than at 86% saturation.

Synthesis of acyclic nucleoside phosphonates targeting flavin-dependent thymidylate synthase in Mycobacterium tuberculosis.

Flavin-Dependent Thymidylate Synthase (FDTS) encoded by ThyX gene was discovered as a new class of thymidylate synthase involved in the de novo synthesis of dTMP named only in 30 % of human pathogenic bacteria. This target was pursed for the development of new antibacterial agents against multiresistant pathogens. We have developed a new class of ANPs based on the mimic of two natural's cofactors (dUMP and FAD) as inhibitors against Mycobacterium tuberculosis ThyX. Several synthetic efforts were performed to optimize regioselective N1-alkylation, cross-coupling metathesis and Sonogashira cross-coupling. Compound 19c showed a poor 31.8% inhibitory effect on ThyX at 200 µM.

Free-living amoebae promote Candida auris survival and proliferation in water.

Candida auris is an emerging species responsible for life-threatening infections. Its ability to be resistant to most systemic antifungal classes and its capacity to persist in a hospital environment have led to health concerns. Currently, data about environmental reservoirs are limited but remain essential in control of C. auris spread. The aim of our study was to explore the interactions between C. auris and two free-living amoeba (FLA) species, Vermamoeba vermiformis and Acanthamoeba castellanii, potentially found in the same water environment. Candida auris was incubated with FLA trophozoites or their culture supernatants. The number of FLA and yeasts was determined at different times and transmission electron microscopy (TEM) was performed. Supernatants of FLAs promoted yeast survival and proliferation. Internalization of viable C. auris within both FLA species was also evidenced by TEM. A water environmental reservoir of C. auris can therefore be considered through FLAs and contamination of the hospital water networks would consequently be possible.

Mechanism of Naphthoquinone Selectivity of Thymidylate Synthase ThyX.

Naphthoquinones (NQs) are natural and synthetic compounds with a wide range of biological activities commonly attributed to their redox activity and/or chemical reactivity. However, genetic and biochemical experiments have recently demonstrated that 2-hydroxy-NQs (2-OH-NQs) act as highly specific noncovalent inhibitors of the essential bacterial thymidylate synthase ThyX in a cellular context. We used biochemical experiments and molecular dynamics simulations to elucidate the selective inhibition mechanism of NQ inhibitors of ThyX from Mycobacterium tuberculosis (Mtb). Free energy simulations rationalized how ThyX recognizes the natural substrate dUMP in the N3-ionized form using an arginine, Arg199, in Mtb. The results further demonstrated that 2-OH-NQ, similar to dUMP, binds to ThyX in the ionized form, and the strong and selective binding of 2-OH-NQ to ThyX is also explained by electrostatic interactions with Arg199. The stronger binding of the close analog 5F-dUMP to ThyX and its inhibitory properties compared with dUMP were explained by the stronger acidity of the uracil N3 atom. Our results, therefore, revealed that the ionization of 2-OH-NQs drives their biological activities by mimicking the interactions with the natural substrate. Our observations encourage the rational design of optimized ThyX inhibitors that ultimately may serve as antibiotics.

Diversity of circular RNAs and RNA ligases in archaeal cells.

Circular RNAs (circRNAs) differ structurally from other types of RNAs and are resistant against exoribonucleases. Although they have been detected in all domains of life, it remains unclear how circularization affects or changes functions of these ubiquitous nucleic acid circles. The biogenesis of circRNAs has been mostly described as a backsplicing event, but in archaea, where RNA splicing is a rare phenomenon, a second pathway for circRNA formation was described in the cases of rRNAs processing, tRNA intron excision, and Box C/D RNAs formation. At least in some archaeal species, circRNAs are formed by a ligation step catalyzed by an atypic homodimeric RNA ligase belonging to Rnl3 family. In this review, we describe archaeal circRNA transcriptomes obtained using high throughput sequencing technologies on Sulfolobus solfataricus, Pyrococcus abyssi and Nanoarchaeum equitans cells. We will discuss the distribution of circular RNAs among the different RNA categories and present the Rnl3 ligase family implicated in the circularization activity. Special focus is given for the description of phylogenetic distributions, protein structures, and substrate specificities of archaeal RNA ligases.

Synthesis and Structure-Activity Relationship Studies of Benzo[b][1,4]oxazin-3(4H)-one Analogues as Inhibitors of Mycobacterial Thymidylate Synthase†X.

Since the discovery of a flavin-dependent thymidylate synthase (ThyX or FDTS) that is absent in humans but crucial for DNA biosynthesis in a diverse group of pathogens, the enzyme has been pursued for the development of new antibacterial agents against Mycobacterium tuberculosis, the causative agent of the widespread infectious disease tuberculosis (TB). In response to a growing need for more effective anti-TB drugs, we have built upon our previous screening efforts and report herein an optimization campaign of a novel series of inhibitors with a unique inhibition profile. The inhibitors display competitive inhibition toward the methylene tetrahydrofolate cofactor of ThyX, enabling us to generate a model of the compounds bound to their target, thus offering insight into their structure-activity relationships.

Facing a New Face: An Interpretative Phenomenological Analysis of the Experiences of a Blind Face Transplant Patient and His Partner.

Increasing evidence points to good functional, aesthetic, and psychosocial outcomes after face transplantation. However, research investigating how patients and their families subjectively experience the transplantation process is lacking thus far. This study aims to investigate the personal experiences of a blind face transplant patient and his partner. In-depth interviews exploring different experiences were conducted with both partners separately 20 months after face transplantation. The interviews were analyzed using interpretative phenomenological analysis. Seven themes were identified in both interviews: coping with the facial trauma, motivation for the face transplantation, outcomes of the face transplantation, acceptance of the new face, gratitude toward the donor family, relation to the medical team, and dealing with the media. Two further themes were only mentioned by the patient (coping with complications and coping with blindness) and one theme only by the partner (loss of choices). The results of this study increase our understanding of the transplantation process as experienced by a face transplant recipient and his partner. They may help to better inform professionals to optimize transplantation procedures or supportive interventions.

Influence of cell confluence on the cAMP signalling pathway in vascular smooth muscle cells.

The influence of cell confluence on the ß-adrenoceptor (ß-AR)/cAMP/phosphodiesterase (PDE) pathway was investigated in cultured rat aortic smooth muscle cells (RASMCs). Cells were plated either at low density (LD: 3·103cells/cm2) or high density (HD: 3·104cells/cm2) corresponding to non-confluent or confluent cells, respectively, on the day of experiment. ß-AR-stimulated cAMP was monitored in real-time using the fluorescence resonance energy transfer (FRET)-based cAMP sensor, Epac2-camps. A brief application (15s) of the ß-AR agonist isoprenaline (Iso) induced a typical transient FRET signal, reflecting cAMP production followed by its rapid degradation. The amplitude of this response, which increased with the concentration of Iso (10 or 100nM), was higher in HD than in LD cells, whatever the Iso concentration used. However, activation of adenylyl cyclase by L-858051 (100µM) induced a similar saturating response in both LD and HD cells. A ß1-AR antagonist (CGP 20712A, 100nM) reduced the Iso (100nM) response in HD but not LD cells, whereas a ß2-AR antagonist (ICI 118,551, 5nM) reduced this response in HD cells and almost abolished it in LD cells. Competitive [125I]-ICYP binding experiments with betaxolol, a ß-AR ligand, identified two binding sites in HD cells, corresponding to ß1- and ß2-ARs with a proportion of 11% and 89%, respectively, but only one binding site in LD cells, corresponding to ß2-ARs. Total cAMP-PDE activity (assessed by a radioenzymatic assay) was increased in HD cells compared to LD cells. This increase was associated with a rise in mRNA expression of five cAMP-PDEs subtypes (PDE1A, 3A, 4A, 4B and 7B) in HD cells, and a decrease in basal [cAMP]i (assessed by an EIA assay). PDE4 inhibition with Ro-20-1724 (10µM) strongly prolonged the Iso response in LD and HD cells, whereas PDE3 inhibition with cilostamide (1µM) slightly prolonged Iso response only in LD cells. Interestingly, inhibition of PDE4 unmasked an effect of PDE3 in HD cells. Our results show that in cultured RASMCs, the ß-AR/cAMP/PDE signalling pathway is substantially modulated by the cell density. In HD cells, Iso response involves both ß1- and ß2-AR stimulation and is mainly controlled by PDE4, PDE3 being recruited only after PDE4 inhibition. In LD cells, Iso response involves only ß2-AR stimulation and is controlled by PDE4 and to a lower degree by PDE3. This low density state is associated with an absence of membrane expression of the ß1-AR, a lower cAMP-PDE activity and a higher basal [cAMP]i. This study highlights the critical role of the cellular environment in controlling the vascular ß-AR signalling.

Discovery of a new Mycobacterium tuberculosis thymidylate synthase X inhibitor with a unique inhibition profile.

Tuberculosis (TB), mainly caused by Mycobacterium tuberculosis (Mtb), is an infection that is responsible for roughly 1.5 million deaths per year. The situation is further complicated by the wide-spread resistance to the existing first- and second-line drugs. As a result of this, it is urgent to develop new drugs to combat the resistant bacteria as well as have lower side effects, which can promote adherence to the treatment regimens. Targeting the de novo synthesis of thymidylate (dTMP) is an important pathway to develop drugs for TB. Although Mtb carries genes for two families of thymidylate synthases (TS), ThyA and ThyX, only ThyX is essential for its normal growth. Both enzymes catalyze the conversion of uridylate (dUMP) to dTMP but employ a different catalytic approach and have different structures. Also, ThyA is the only TS found in humans. This is the rationale for identifying selective inhibitors against ThyX. We exploited the NADPH oxidation to NADP+ step, catalyzed by ThyX, to develop a spectrophotometric biochemical assay. Success of the assay was demonstrated by its effectiveness (average Z'=0.77) and identification of selective ThyX inhibitors. The most potent compound is a tight-binding inhibitor with an IC50 of 710nM. Its mechanism of inhibition is analyzed in relation to the latest findings of ThyX mechanism and substrate and cofactor binding order.

High-throughput sequencing reveals circular substrates for an archaeal RNA ligase.

It is only recently that the abundant presence of circular RNAs (circRNAs) in all kingdoms of Life, including the hyperthermophilic archaeon Pyrococcus abyssi, has emerged. This led us to investigate the physiologic significance of a previously observed weak intramolecular ligation activity of Pab1020 RNA ligase. Here we demonstrate that this enzyme, despite sharing significant sequence similarity with DNA ligases, is indeed an RNA-specific polynucleotide ligase efficiently acting on physiologically significant substrates. Using a combination of RNA immunoprecipitation assays and RNA-seq, our genome-wide studies revealed 133 individual circRNA loci in P. abyssi. The large majority of these loci interacted with Pab1020 in cells and circularization of selected C/D Box and 5S rRNA transcripts was confirmed biochemically. Altogether these studies revealed that Pab1020 is required for RNA circularization. Our results further suggest the functional speciation of an ancestral NTase domain and/or DNA ligase toward RNA ligase activity and prompt for further characterization of the widespread functions of circular RNAs in prokaryotes. Detailed insight into the cellular substrates of Pab1020 may facilitate the development of new biotechnological applications e.g. in ligation of preadenylated adaptors to RNA molecules.

Adsorption of norovirus and ostreid herpesvirus type 1 to polymer membranes for the development of passive samplers.

AIMS: This study was performed to develop a passive sampling methodology for the detection of two viruses in seawater in the area of shellfish production, the norovirus (NoV), a human pathogen implicated in gastroenteritis outbreaks linked to oyster consumption and the ostreid herpesvirus type 1 (OsHV-1), a virus associated with mass mortalities of Pacific oysters. METHODS AND RESULTS: Commercially, membranes were tested for their capacity to adsorb virus: zetapor, gauze, nylon, low-density polyethylene (LDPE) and polyvinylidene difluoride (PVDF). Laboratory exposures of membranes to contaminated water samples (stool, sewage, seawater) were performed. Our data show that the amount of NoV GII genome per membrane measured with qRT-PCR increased with the time of exposure up to 24 h, for all types of membranes except gauze. After 15 days of exposure, the amount of NoV GII per membrane continued to increase only for nylon and LDPE. The amount of OsHV-1 per zetapor membrane was significantly increased as soon as 4 h of exposure, and after 24 h of exposure for all types of membranes. Exposure of membranes to serial dilutions of various samples revealed that the amount of NoV GII and OsHV-1 per membrane is significantly higher in diluted samples. The detection of NoV and OsHV-1, respectively, with zetapor and PVDF membranes was found to be more efficient than the direct analysis of sewage and seawater. CONCLUSIONS: All membranes immersed in contaminated samples adsorbed NoV GII and OsHV-1. The amount of both viruses increased with the time of exposure. Zetapor and PVDF membranes seem to be more adapted to NoV GII and OsHV-1 detection respectively. SIGNIFICANCE AND IMPACT OF THE STUDY: Membranes tested will be used as passive samplers to improve the detection of virus in oyster production areas. Also, passive samplers could be a valuable tool for microbiome analysis with new generation sequencing.

Predictive modeling targets thymidylate synthase ThyX in Mycobacterium tuberculosis.

There is an urgent need to identify new treatments for tuberculosis (TB), a major infectious disease caused by Mycobacterium tuberculosis (Mtb), which results in 1.5 million deaths each year. We have targeted two essential enzymes in this organism that are promising for antibacterial therapy and reported to be inhibited by naphthoquinones. ThyX is an essential thymidylate synthase that is mechanistically and structurally unrelated to the human enzyme. DNA gyrase is a DNA topoisomerase present in bacteria and plants but not animals. The current study set out to understand the structure-activity relationships of these targets in Mtb using a combination of cheminformatics and in vitro screening. Here, we report the identification of new Mtb ThyX inhibitors, 2-chloro-3-(4-methanesulfonylpiperazin-1-yl)-1,4-dihydronaphthalene-1,4-dione) and idebenone, which show modest whole-cell activity and appear to act, at least in part, by targeting ThyX in Mtb.

Long-Term Multifunctional Outcome and Risks of Face Vascularized Composite Allotransplantation.

Vascularized composite allotransplantation (VCA) to reconstruct complex centrally located facial defects and to restore vital functions in a 1-staged procedure has worldwide gained acceptance. Continuous long-term multidisciplinary follow-up of face transplant patients is mandatory for surveillance of the complications associated with the immunosuppressive regime and for functional assessment of the graft. In December 2011, our multidisciplinary team performed a digitally planned face transplant at the Ghent University Hospital, Belgium on a 55-year-old man with a large central facial defect after a high-energy ballistic injury. The patient was closely followed to assess functional recovery, immunosuppressive complications, overall well-being, and quality of life. Three years postoperatively, the patient and his family are very satisfied with the overall outcome, and social reintegration in the community is successful. Motor and sensory functions have recovered near normal. Infectious and medical complications have been serious but successfully managed. Immunosuppressive maintenance therapy consists of corticoids, tacrolimus, and mycophenolate mofetil in minimal doses. Epithetic reconstruction of both eyes gave a tremendous improvement on the overall aesthetic outcome. Despite serious complications during the first 12 months, multifunctional outcome in the first face transplant in Belgium (#19 worldwide) is successful. This should be attributed to the continuous and long-term multidisciplinary team approach. As only few reports of other face transplant patients on long-term follow-up are available, more data need to be collected and reported to further outweigh the risk benefit ratio of this life changing surgery.

Facial transplantation in a blind patient: psychologic, marital, and family outcomes at 15 months follow-up.

BACKGROUND: Quality of life has frequently been reported to improve after vascularized composite allotransplantation of the face. However, psychosocial functioning of the partner or of particular patient groups such as blind patients are until now less well investigated. OBJECTIVE: The aim of this study is to investigate psychologic, marital, and family functioning of a blind 54-year-old patient, Mr. A, and his partner after facial transplantation. METHODS: Depressive and anxiety symptoms, hopelessness, personality, coping, resilience, illness cognitions, marital support, dyadic adjustment, family functioning, and quality of life of Mr. A and his partner were assessed before and after facial transplantation and at 15 months follow-up. Reliable change index (RCI) was further calculated to evaluate the magnitude of change. RESULTS: Most psychologic, marital, and family scores of both Mr. A and his partner were within a normative and healthy range before and after transplant and at 15 months follow-up. Resilience (RCI: 3.6), affective responsiveness (RCI: -3.6), and disease benefits (RCI: 2.6) of Mr. A further improved at 15 months follow-up whereas the physical quality of life (RCI: -14.8) strongly decreased. Only marital support (RCI: -2.1) and depth (RCI: -2.0) of the partner decreased at 15 months. CONCLUSIONS: The results of this study point to positive psychosocial outcomes in a blind patient after facial transplantation. Further, they may underscore the importance of good psychosocial functioning before transplantation of both partners and of their involvement in psychologic and psychiatric treatment. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, V.

Complex facial reconstruction by vascularized composite allotransplantation: the first Belgian case.

INTRODUCTION: Complex injuries to the central part of the face are difficult to reconstruct with the current plastic surgery methods. The ultimate one-staged approach to restore anatomy and vital facial functions is to perform a vascularized composite allotransplantation (VCA). METHODS: A 54-year-old man suffered from a high-energy ballistic injury, resulting in a large central facial defect. A temporary reconstruction was performed with a free plicated anterolateral thigh (ALT) flap. Considering the goal to optimally restore facial function and aesthetics, VCA was considered as an option for facial reconstruction. A multidisciplinary team approach, digital planning, and cadaver sessions preceded the transplantation. RESULTS: A digitally planned facial VCA was performed involving the bilateral maxillae, the hard palate, a part of the left mandible, and the soft tissues of the lower two-thirds of the face. Due to meticulous preparations, minimal adjustments were necessary to achieve good fitting in the recipient. At week 17, a grade 4 rejection was successfully treated; sensory and motor recovery was noted to occur from the fourth postoperative month. Several serious infectious and medical problems have occurred until 15-months postoperatively; following that, the clinical situation has remained stable. Two years postoperatively, the patient and his family are very satisfied with the overall outcome and social reintegration in the community is successful. CONCLUSION: The first face transplant in Belgium (#19 worldwide) was successful because of a meticulous 3-year preparation by a large multidisciplinary team. In our experience, preparatory cadaver dissections and three-dimensional (3D) computed tomographic (CT) modeling were valuable tools for an optimal intraoperative course and good alignment of the bony structures. Continuous long-term multidisciplinary follow-up is mandatory for surveillance of the complications associated with the immunosuppressive regime and for functional assessment of the graft.

Alteration of vascular reactivity in heart failure: role of phosphodiesterases 3 and 4.

BACKGROUND AND PURPOSE: This study examined the role of the main vascular cAMP-hydrolysing phosphodiesterases (cAMP-PDE) in the regulation of basal vascular tone and relaxation of rat aorta mediated by ß-adrenoceptors, following heart failure (HF). EXPERIMENTAL APPROACH: Twenty-two weeks after proximal aortic stenosis, to induce HF, or SHAM surgery in rats, we evaluated the expression, activity and function of cAMP-PDE in the descending thoracic aorta. KEY RESULTS: HF rat aortas exhibited signs of endothelial dysfunction, with alterations of the NO pathway, and alteration of PDE3 and PDE4 subtype expression, without changing total aortic cAMP-hydrolytic activity and PDE1, PDE3 and PDE4 activities. Vascular reactivity experiments using PDE inhibitors showed that PDE3 and PDE4 controlled the level of PGF2α -stimulated contraction in SHAM aorta. PDE3 function was partially inhibited by endothelial NO, whereas PDE4 function required a functional endothelium and was under the negative control of PDE3. In HF, PDE3 function was preserved, but its regulation by endothelial NO was altered. PDE4 function was abolished and restored by PDE3 inhibition. In PGF2α -precontracted arteries, ß-adrenoceptor stimulation-induced relaxation in SHAM aorta, which was abolished in the absence of functional endothelium, as well as in HF aortas, but restored after PDE3 inhibition in all unresponsive arteries. CONCLUSIONS AND IMPLICATIONS: Our study underlines the key role of the endothelium in controlling the contribution of smooth muscle PDE to contractile function. In HF, endothelial dysfunction had a major effect on PDE3 function and PDE3 inhibition restored a functional relaxation to ß-adrenoceptor stimulation.