Search

Vascularized composite allografts (VCA) face ischemic challenges due to their limited availability. Reperfusion following ischemia triggers oxidative stress and immune reactions, and scavenger molecules could mitigate ischemia–reperfusion injuries and, therefore, immune rejection. We compared two scavengers in a myocutaneous flap VCA model. In total, 18 myocutaneous flap transplants were performed in Major histocompatibility complex (MHC)-defined miniature swine. In the MATCH group (n = 9), donors and recipients had minor antigen mismatch, while the animals were fully mismatched in the MISMATCH group (n = 9). Grafts were pretreated with saline, sodium iodide (NaI), or hydrogen sulfide (H2S), stored at 4 °C for 3 h, and then transplanted. Flaps were monitored until clinical rejection without immunosuppression. In the MATCH group, flap survival did not significantly differ between the saline and hydrogen sulfide treatments (p = 0.483) but was reduced with the sodium iodide treatment (p = 0.007). In the MISMATCH group, survival was similar between the saline and hydrogen sulfide treatments (p = 0.483) but decreased with the sodium iodide treatment (p = 0.007). Rhabdomyolysis markers showed lower but non-significant levels in the experimental subgroups for both the MATCH and MISMATCH animals. This study provides insightful data for the field of antioxidant-based approaches in VCA and transplantation.

Reconstructive techniques to repair severe tissue defects include the use of autologous fasciocutaneous flaps, which may be limited due to donor site availability or lead to complications such as donor site morbidity. A number of synthetic or natural dermal substitutes are in use clinically, but none have the architectural complexity needed to reconstruct deep tissue defects. The perfusion decellularization of fasciocutaneous flaps is an emerging technique that yields a scaffold with the necessary composition and vascular microarchitecture and serves as an alternative to autologous flaps. In this study, we show the perfusion decellularization of porcine fasciocutaneous flaps using sodium dodecyl sulfate (SDS) at three different concentrations, and identify that 0.2% SDS results in a decellularized flap that is efficiently cleared of its cellular material at 86%, has maintained its collagen and glycosaminoglycan content, and preserved its microvasculature architecture. We further demonstrate that the decellularized graft has the porous structure and growth factors that would facilitate repopulation with cells. Finally, we show the biocompatibility of the decellularized flap using human dermal fibroblasts, with cells migrating as deep as 150 µm into the tissue over a 7-day culture period. Overall, our results demonstrate the promise of decellularized porcine flaps as an interesting alternative for reconstructing complex soft tissue defects, circumventing the limitations of autologous skin flaps.

Silk spinning, observed in spiders and insects, exhibits a remarkable biological source of inspiration for advanced polymer fabrications. Because of the systems design, silk spinning represents a holistic and circular approach to sustainable polymer fabrication, characterized by renewable resources, ambient and aqueous processing conditions, and fully recyclable “wastes.” Also, silk spinning results in structures that are characterized by the combination of monolithic proteinaceous composition and mechanical strength, as well as demonstrate tunable degradation profiles and minimal immunogenicity, thus making it a viable alternative to most synthetic polymers for the development of advanced biomedical devices. However, the fundamental mechanisms of silk spinning remain incompletely understood, thus impeding the efforts to harness the advantageous properties of silk spinning. Here, we present a concise and timely review of several essential features of silk spinning, including the molecular designs of silk proteins and the solvent cues along the spinning apparatus. The solvent cues, including salt ions, pH, and water content, are suggested to direct the hierarchical assembly of silk proteins and thus play a central role in silk spinning. We also discuss several hypotheses on the roles of solvent cues to provide a relatively comprehensive analysis and to identify the current knowledge gap. We then review the state-of-the-art bioinspired fabrications with silk proteins, including fiber spinning and additive approaches/three-dimensional (3D) printing. An emphasis throughout the article is placed on the universal characteristics of silk spinning developed through millions of years of individual evolution pathways in spiders and silkworms. This review serves as a stepping stone for future research endeavors, facilitating the in vitro recapitulation of silk spinning and advancing the field of bioinspired polymer fabrication.

Linear prediction models based on data with large inhomogeneity or abrupt non-linearities often perform poorly because relationships between groups in the data dominate the model. Given that the data is locally linear, this can be overcome by splitting the data into smaller clusters and creating a local model within each cluster. In this study, the previously published Hierarchical Cluster-based Partial Least Squares Regression (HC-PLSR) procedure was extended to deep learning, in order to increase the interpretability of the deep learning models through local modelling. Hierarchical Cluster-based Convolutional Neural Networks (HC-CNNs), Hierarchical Cluster-based Recurrent Neural Networks (HC-RNNs) and Hierarchical Cluster-based Support Vector Regression models (HC-SVRs) were implemented and tested on spectroscopic data consisting of Fourier Transform Infrared (FT-IR) measurements of raw material dry films, for prediction of average molecular weight during hydrolysis and a simulated data set constructed to contain three clusters of observations with different non-linear relationships between the independent variables and the response. HC-CNN, HC-RNN and HC-SVR outperformed HC-PLSR for the simulated data set, showing the disadvantage of PLSR for highly non-linear data, but for the FT-IR data set there was little to gain in prediction ability from using more complex models than HC-PLSR. Local modelling can ease the interpretation of deep learning models through highlighting differences in feature importance between different regions of the input or output space. Our results showed clear differences between the feature importance for the various local models, which demonstrate the advantages of a local modelling approach with regards to interpretation of deep learning models.

Abstract Background The lateral chest wall is intimately associated with the esthetics of the breast. Patients with massive weight loss often have excess skin and fat in the lateral thoracic region causing functional, esthetic, and psychological discomfort. In addition, the breasts exhibit extreme ptosis after weight loss due to a reduction in volume and projection that is exacerbated by qualitative changes in the skin, with loss of its natural elasticity. This article describes a reliable new technique for simultaneous autologous breast augmentation and lateral thoracic dermolipectomy to provide autologous tissue for breast augmentation and simultaneous rejuvenation of the chest wall. Case presentation A 30-year-old Caucasian woman who had lost 58 kg after bariatric surgery had major skin excess sequelae combined with major breast ptosis. She wanted to correct her brachial and lateral thoracic skin and fat excess, as well as rejuvenate her breasts. The lateral thoracic panicle present was harvested and transposed in the retroglandular plane to perform autologous breast augmentation with lateral thoracic dermolipectomy. Results The patient was totally healed and complication-free at day 15. Both esthetic results and patient satisfaction were good at 6 months post-surgery. Conclusions Superolateral thoracic flap augmentation mammaplasty during thoracic dermolipectomy is a simple and safe procedure for selected patients. Durable and natural autologous breast augmentation may be achieved in a single step without the need for a breast implant, while rejuvenating the thoracic region.

The disappearance of the Oxus Civilization in southern Central Asia in the middle of the second millennium BCE represents a major break in the historical development of the area and forms an interesting study case of sociocultural transitions. Through the examination of the evolution of the ceramic productions at this period, the article discusses the impact of the interactions between the diverse cultural groups on the changes, as well as the spatiotemporal variability of the transitional processes between the Bronze and Iron Ages.

Background: Nanofat grafting (NG) is a simple and cost-effective method of lipoaspirates with inter-syringe passages, to produce stromal vascular fraction (SVF) and isolate adipose-derived stem cells (ASCs). This represents a tremendous interest in the future clinical needs of tissue engineering. In this study, we optimized the NG technique to increase the yield of ASC extractions.Methods: We analyzed three groups of SVF obtained by 20, 30, and 40 inter-syringe passages. The control group was an SVF obtained by enzymatic digestion with Celase. We studied their cell composition by flow cytometry, observed their architecture by confocal microscopy, and observed immunomodulatory properties of the ASCs from each of the SVFs by measuring inflammatory markers of macrophages obtained by an ASC monocyte co-culture.Results: We have established the first cell mapping of the stromal vascular fraction of adipose tissue. The results showed that SVF obtained by 20 inter-syringe passages contains more statistically significant total cells, more cells expressing the ASC phenotype, more endothelial cells, and produces more CFU-F than the SVF obtained by 30 and 40 passages and by enzymatic digestion. Confocal microscopy showed the presence of residual adipocytes in SVF obtained by inter-syringe passages but not by enzymatic digestion. The functional study indicates an orientation toward a more anti-inflammatory profile and homogenization of their immunomodulatory properties.Conclusion: This study places mechanically dissociated SVF in the center of approaches to easily extract ASCs and a wide variety and number of other progenitor cells, immediately available in a clinical setting to provide both the amount and quality of cells required for decellularized tissues.

Abstract Background The quality of nursing clinical placements has been found to vary. Placement evaluation tools for nursing students are available but lack contemporary reviews of clinical settings. Therefore, the aim of this study was to develop a feasible, valid and reliable clinical placement evaluation tool applicable to nursing student placements in Australia. Methods An exploratory mixed methods co-design project. Phase 1 included a literature review; expert rating of potential question items and Nominal Group Technique meetings with a range of stakeholders for item development. Phase 2 included on-line pilot testing of the Placement Evaluation Tool (PET) with 1263 nursing students, across all year levels at six Australian Universities and one further education college in 2019–20, to confirm validity, reliability and feasibility. Results The PET included 19-items (rated on a 5-point agreement scale) and one global satisfaction rating (a 10-point scale). Placements were generally positively rated. The total scale score (19 items) revealed a median student rating of 81 points from a maximum of 95 and a median global satisfaction rating of 9/10. Criterion validity was confirmed by item correlation: Intra-class Correlation Co-efficient ICC = .709; scale total to global score r = .722; and items to total score ranging from .609 to .832. Strong concurrent validity was demonstrated with the Clinical Learning Environment and Supervision Scale (r = .834). Internal reliability was identified and confirmed in two subscale factors: Clinical Environment (Cronbach’s alpha = .94) and Learning Support (alpha = .96). Based on the short time taken to complete the survey (median 3.5 min) and students’ comments, the tool was deemed applicable and feasible. Conclusions The PET was found to be valid, reliable and feasible. Use of the tool as a quality assurance measure is likely to improve education and practice in clinical environments. Further international evaluation of the instrument is required to fully determine its psychometric properties.

The blockages of pipelines caused by agglomeration of gas hydrates is a major flow assurance issue in the oil and gas industry. Some crude oils form gas hydrates that remain as transportable particles in a slurry. It is commonly believed that naturally occurring components in those crude oils alter the surface properties of gas hydrate particles when formed. The exact structure of the crude oil components responsible for this surface modification remains unknown. In this study, a successive accumulation and spiking of hydrate-active crude oil fractions was performed to increase the concentration of hydrate related compounds. Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FT-ICR MS) was then utilised to analyse extracted oil samples for each spiking generation. Machine learning-based variable selection was used on the FT-ICR MS spectra to identify the components related to hydrate formation. Among six different methods, Partial Least Squares Discriminant Analysis (PLS-DA) was selected as the best performing model and the 23 most important variables were determined. The FT-ICR MS mass spectra for each spiking level was compared to samples extracted before the successive accumulation, to identify changes in the composition. Principal Component Analysis (PCA) exhibited differences between the oils and spiking levels, indicating an accumulation of hydrate active components. Molecular formulas, double bond equivalents (DBE) and hydrogen-carbon (H/C) ratios were determined for each of the selected variables and evaluated. Some variables were identified as possibly asphaltenes and naphthenic acids which could be related to the positive wetting index (WI) for the oils.

Abstract Background Soft tissue sarcomas affecting the root of an upper extremity raise the question of limb amputation depending on their location, size, and malignancy. Malignant triton tumors are a rare subtype of neurofibrosarcomas that have been poorly reported in the literature. We report the case of a challenging reconstruction of the upper extremity using a pedicled latissimus dorsal flap. Case presentation A 25-year-old Occidental man was referred to our sarcoma unit for the management of a large, high-grade malignant peripheral nerve sheath tumor with no regional or distant extension and very fast progression. He was treated first by concomitant neoadjuvant radiotherapy and chemotherapy. Carcinologic excision was performed “en bloc” including the skin, the tumor, and the flexor muscles of our patient’s elbow. Coverage of the skin defect and elbow flexion restoration were achieved by using a homolateral pedicled musculocutaneous latissimus dorsi flap. Histological analysis showed an R0 resection. The reconstruction process recovered a complete bending of his elbow. He is still in remission at 26 months follow-up. Conclusions A malignant triton tumor is a rare, aggressive, and high-grade sarcoma. It was successfully treated and this case report describes an effective treatment modality. Reconstructive surgery, allowing large, complete tumor removal, is indispensable after neoadjuvant chemotherapy and radiotherapy.

Introduction Clinical placements are a mandatory component of nursing students’ education internationally. Despite clinical education being a key to nursing students’ achievement of nursing competencies, few studies have reviewed students’ narratives to describe their experiences of learning during clinical placement. Such studies may be important in offering a deeper insight into clinical learning experiences than quantitative surveys. Methods A s ystematic thematic synthesis of qualitative studies between 2010 and June 2020 was conducted. English language studies that offered a thematic analysis of undergraduate nursing students’ experiences of learning during placement were sought. A search was made of five databases PubMed, Ovid Medline, CinahlPlus, SCOPUS, and Google Scholar. The study was guided by the ENTREQ statement for enhancing transparency in reporting the synthesis of qualitative research. Results Twenty-seven qualitative studies were included in the review. A thematic synthesis showed over 100 themes and subthemes across the studies. A cluster analysis revealed positive elements and others that were seen in the studies as a barrier (hindrance) to clinical learning. Positive elements included supportive instructors, close supervision, and belonging (in the team). Unsupportive instructors, a lack of supervision and not being included were seen as a hindrance. Three key overarching themes that could describe a successful placement were revealed as “Preparation,” “Welcomed and wanted” and “Supervision experiences”. A conceptual model of clinical placement elements conducive to nursing students’ learning was developed to enhance understanding of the complexities associated with supervision. The findings and model are presented and discussed. Conclusion The conceptual model presents positive elements that influence students’ clinical placement experiences of learning. This model may provide a framework to guide professional development programs and strategies to support students and supervisors alike, an important step forward in moving beyond the current clinical placement rhetoric.

Introduction: Hidradenitis suppurativa (HS) is a common and debilitating disease, in which the only effective treatment involves a wide excision of the affected skin. Secondary wound healing and skin grafting are two well-known options for managing these defects, but perforator flaps provide a new therapeutic alternative by ensuring reconstructions of large defects, reducing donor site morbidity, and enhancing functional recovery. The aim of this study was to achieve a systematic review of perforator flaps use in HS. Patients and Methods: PubMed and Cochrane databases were searched from 1989 to 2021. The PRISMA statement was used in the study selection process and the review was registered on PROSPERO. Furthermore, patient characteristics, operative technique, complications, and recurrences were searched. Results: Thirty-six articles were selected including 286 patients and 387 flaps. Axillary localization was mostly represented (83.2%). Direct donor site closure was achieved in 99.1% of cases. In total, 15.1% of the flaps presented at least one of the following complications: wound dehiscence (5.5%), partial necrosis (2.9%), hematoma or seroma (2.1%), infection (2.1%), venous congestion (1.8%), and nerve injury (0.3%). Two cases of total necrosis were recorded. Recurrence of the disease was observed in 2.7% of the defects. Conclusions: Pedicled perforator flaps are a reliable and reproducible technique in the reconstruction of HS defects. They are associated with a low recurrence rate while ensuring an effective reconstruction with reduced morbidity and faster recovery compared to the techniques classically used in this indication.

Abstract Background Hirschsprung disease is a neonatal discovery in almost all cases, and the association of Hirschsprung disease in adults with symptomatic intestinal malrotation is unusual. This combination delays diagnosis and can lead to mistake in surgical strategy. Case presentation A 43-year-old patient with a history of colectomy for colonic inertia and megadolichocolon was admitted to the Carcassonne Hospital emergency room for a volvulus of small bowel obstruction in a chronic intestinal obstruction context with episodes of acute, variable-looking occlusive syndromes. Intestinal malrotation was discovered during surgical small bowel detorsion. The acute occlusion syndrome recurred after the procedure. In view of the unfavorable evolution, an emptying of the dilated small bowel and a discharge ileostomy upstream of the rectum were performed. In the face of postoperative improvement, rectal manometry and deep full parietal rectal biopsies made it possible to highlight the diagnosis of Hirschsprung disease. The patient thus had functional acute occlusive syndromes and chronic occlusion due to Hirschsprung disease of attenuated form and acute organic occlusive syndromes related to her incomplete common mesentery. Conclusions This rare association, which may be responsible for delayed diagnostic and therapeutic wandering, highlights the importance of performing manometry and deep full parietal biopsies before a colectomy for colonic inertia, as well as the possibility of suggesting a common Hirschsprung disease and/or mesentery in an adult with multiple occlusive syndromes of variable appearance.

Purpose: The decellularization of Vascularized Composite Allotransplantation (VCA) represents a first step in circumventing the need for immunosuppression by depleting donor cells from VCAs. Here we present a model of decellularization of VCAs in rats. Methods: Rat hind limbs based upon the common femoral artery were harvested and perfused through the vascular pedicle at 1ml/min through with 1% sodium dodecyl sulfate (SDS) (group 1) or 0.2% SDS (group 2) or were immersed in SDS 1% (group 3), followed by perfusion (group 1 and 2) or immersion (group 3) in 1% Triton X-100. The degree of decellularization was assessed quantitatively by determining DNA content and qualitatively by histology in all groups at the same locations. The group yielding best decellularization outcome was selected for further assessment for the preservation of ECM content and vasculature and was transplanted orthotopically to assess the ability to reperfuse these decellularized limbs in vivo. RESULTS - Gross examination and DNA quantification of less than 50 ng/mg tissue demonstrated successful decellularization only in group 2 while preserving tissue matrix architecture, including vessels. The arterial network was found to be perfusable and intact during in vivo orthotopic transplantation of the decellularized limb. No outflow was observed, however, after 115 minutes of arterial reperfusion. Conclusions: We describe a successful decellularization protocol for rat hindlimb VCAs by perfusion ex-vivo of 1% SDS. During its in vivo transplantation, decellularization alone allows for a perfusable arterial network and with further optimization, we aim to achieve venous perfusion as well.

Les pays à faibles et moyens revenus sont les plus affectées par les maladies nécessitant une intervention chirurgicale ou obstétrique. Ainsi, 5 milliards de personnes n´ont pas accès à ces soins et ne possède pas les ressources nécessaires pour lutter contre ce fardeau. La chirurgie globale est un domaine d´étude, de recherche, de pratique et de plaidoirie visant à améliorer et à promouvoir l´équité en matière de santé pour toutes les personnes nécessitant des soins chirurgicaux, obstétricaux et anesthésiques. Ce domaine est récent et encore peu connu, notamment par la communauté francophone.

Purpose: The current gold standard in organ storage is static cold storage (SCS) at 4°C in a preservation solution (UW, HTK). While kidneys can be stored for 24 hours in SCS, Vascularized Composite Allografts (VCA) have been transplanted up to 12 hours in this condition. We aimed to determine the limits of VCA viability with SCS. We used a partial heterotopic hindlimb transplantation model on rodent to assess VCA survival at various durations of SCS. Methods: Right partial hind limbs in Lewis rats were procured and a 24G Angiocath inserted in the femoral artery. Limbs were flushed with 2ml of heparin saline (100UI/ml) at room temperature and then 5ml of ice cold HTK solution. The limbs were then immersed in HTK in a sterile bag and stored at 4°C for a period of 12(group 1), 18(group 2), 24(group 3), 48 (group 4) or 0 hours (fresh controls Group 5), before microsurgical transfer to the opposite groin. Graft weight was assessed before and after cold storage. At post-operative day (POD) 21, VCAs were harvested for histological analysis. Results: In all groups, there was no significant difference of weight gain in SCS groups after extended SCS times. In group 1 (n=4), 3 rats survived until POD21; clinical evolution showed a limited epidermolysis (

An amendment to this paper has been published and can be accessed via the original article.

The study of the funeral practices of the Oxus civilization − a sedentary agro-pastoral and proto-state society located in southern Central Asia and dated from the Bronze Age (2400-1500 BCE) − allowed the particular social structure related to gender of this society to be shed in light. Female graves may contain more funeral gifts and more artefacts in precious material. In addition, a preferential distribution of the funeral goods in relation with the sex of the individuals and the type of graves could be observed. Some objects are nearly exclusively associated to women, whereas others to men. A connection between the types of funeral goods and the sex of the individuals appears obvious, although some variations look like normative conflicts, which remains to be interpreted. Nevertheless, the goods put in the graves could have acted as attributes of gender or of functions.The precise examination of the material culture and the iconography associated to each sex question the assertions previously raised concerning the social roles and status of the individuals in relation with the gender. It contributes to review our positions on the social activities, the status of women and men, and their relation, as well as to redefine the roles and powers of each one. The analysis allows thus the social organization of the Oxus civilization to be considered in a new way, particularly the gender system, which seems to be based more on an equality of status and a complementarity of powers and functions between men and women.

Deze studie1 gaat over de manieren waarop de waarde van opties toegekend aan ondernemingsbestuurders kan worden beïnvloed. Het onderzoek is gebaseerd op data van ondernemingen genoteerd aan Euronext Amsterdam in de jaren 1999-2004. Een manier om de aandelenkoers waarop in het algemeen de uitoefenprijs van de opties is gebaseerd, te beïnvloeden, is door het uitbrengen van persberichten. Om de waardestijging van de toegekende opties te maximeren, is het aantrekkelijk om tegen een zo laag mogelijke prijs in het bezit van de opties te komen. Dit kan geschieden door vóór de datum van toekenning (zeer) negatief ondernemingsnieuws te publiceren. Daardoor zal de koers van het onderliggende aandeel en daarmee de koers van de opties dalen. Na de toekenning van de opties zal de waarde ervan kunnen toenemen door het uitbrengen van (zeer) positieve persberichten. De uitkomsten van deze studie tonen aan dat opties vooral aan bestuurders van grotere ondernemingen worden verstrekt. In de periode 1999-2004 blijken negatieve persberichten vóór de toekenningsdatum te worden gepubliceerd, terwijl positieve berichten na de toekenningsdatum bekendgemaakt worden. De uitgevoerde logistische regressies zijn consistent met genoemde uitkomsten.

The aim of this study was to test seven previously published image-input methods in state-of-the-art high resolution PET brain images. Images were obtained with a High Resolution Research Tomograph plus a resolution-recovery reconstruction algorithm using two different radioligands with different radiometabolite fractions. Three of the methods required arterial blood samples to scale the image-input, and four were blood-free methods.All seven methods were tested on twelve scans with [(11)C](R)-rolipram, which has a low radiometabolite fraction, and on nineteen scans with [(11)C]PBR28 (high radiometabolite fraction). Logan V(T) values for both blood and image inputs were calculated using the metabolite-corrected input functions. The agreement of image-derived Logan V(T) values with the reference blood-derived Logan V(T) values was quantified using a scoring system. Using the image input methods that gave the most accurate results with Logan analysis, we also performed kinetic modelling with a two-tissue compartment model.For both radioligands the highest scores were obtained with two blood-based methods, while the blood-free methods generally performed poorly. All methods gave higher scores with [(11)C](R)-rolipram, which has a lower metabolite fraction. Compartment modeling gave less reliable results, especially for the estimation of individual rate constants.OUR STUDY SHOWS THAT: 1) Image input methods that are validated for a specific tracer and a specific machine may not perform equally well in a different setting; 2) despite the use of high resolution PET images, blood samples are still necessary to obtain a reliable image input function; 3) the accuracy of image input may also vary between radioligands depending on the magnitude of the radiometabolite fraction: the higher the metabolite fraction of a given tracer (e.g., [(11)C]PBR28), the more difficult it is to obtain a reliable image-derived input function; and 4) in association with image inputs, graphical analyses should be preferred over compartmental modelling.