A Treatment Algorithm for Free Vascularized Bone Reconstruction in Rare Large Osseous Defects Involving the Wrist.

Large bone defects of the distal radius and/or carpus following tumor resection, trauma, or infection are extremely rare. There are few case reports and series in the literature on the reconstruction approaches required in such cases. Therefore, large studies cannot be used to guide the therapeutic decisions of reconstructive plastic and hand surgeons. The objective of this study is to propose a treatment algorithm to predict the functional outcome and quality of life for the different techniques of free vascularized bone reconstruction in the interval between the distal radius, the carpus, and/or the proximal metacarpal. The algorithm was developed based on our own case studies and the few treatment approaches described in the literature. It can be applied to rare cases of massive bone defects in the wrist. The flowchart enables surgeons to develop an individualized reconstruction concept for various intervals of bone defects in the area of the distal radius and proximal metacarpal bones. Ultimately, the treatment algorithm aims to maximize future quality of life (QoL) and function of the distal upper extremity in rare cases of massive wrist-bone defects.

Is overweight a predictor for a more severe course of disease in cases of necrotizing fasciitis?

PURPOSE: Necrotizing fasciitis is a rare but severe soft tissue infection, and its diagnosis is difficult and often delayed. Immediate treatment comprising extensive debridement, highly dosed broad-spectrum antibiotic therapy and intensive care is necessary to prevent fatal outcomes. Considering the global rise in overweight patients and the known negative effects of obesity on the immune system, the aim of this study was to analyze whether overweight results in a more severe course of necrotizing fasciitis, worse outcomes and an increased mortality rate among overweight patients compared than in normal weight patients. METHODS: The present study involved a retrospective analysis of 29 patients who were treated for necrotizing fasciitis in our level one trauma center during the eight-year period between 2013 and 2020. Based on their BMIs, the patients were assigned to either the overweight group (BMI > 25) or the normal weight group. RESULTS: In the study population, being overweight appeared to be a predictor for a more severe course of necrotizing fasciitis. Overweight patients suffered from sepsis significantly more often than normal weight patients (13 vs. 5; p = 0.027). Furthermore, they were dependent on invasive ventilation (26.6 ± 33.8 vs. 5.9 ± 11.9 days; p = 0.046) as well as catecholamine support (18.4 ± 23.7 vs. 3.6 ± 5.7 days; p = 0.039) for significantly longer. CONCLUSION: Necrotizing fasciitis remains a challenging and potentially fatal disease. Within the patient collective, the severity of the disease and treatment effort were increased among overweight patients.

Lower Extremity Open Fractures Fix and Flap: Does Initial Management in Non-specialized Hospitals Really Compromise its Outcome?

Introduction Managing open lower extremity fractures is challenging, with potential complications such as amputation and infection. The aim of the study was to determine whether the time delay and initial treatment of the patients treated in a non-specialized hospital before being transferred to a dedicated level I trauma center led to a worse outcome. Methods Retrospective data from 44 patients (37 males and seven females) undergoing free tissue transfer for lower extremity open fractures from January 2017 to December 2022 were analyzed. Group A received primary care externally and was later transferred for definitive treatment (n=17, 38.6%), while group B received initial care at a level I trauma center (n=27, 61.4%). Surgical outcomes, complications, the duration of the hospital stay, and assessment times were compared. Various demographic variables, co-morbidities, prior interventions, and flap types were analyzed.  Results Average age (A: 55.1±16.7; B: 38.7±19.8 years; p=0.041), overall hospitalization (A: 55.7±22.8; B: 42.8±21.3 days; p=0.041), and time to soft tissue reconstruction differed significantly between groups (A: 30.7±12.2; B: 18.9±9.3 days; p=0.013). Overall, 31.8% had multiple injuries without statistical differences between groups A and B (29.4% vs. 33.3%; p>0.05). There were no statistical differences between the groups in terms of major and minor complications and bone healing characteristics. Limb salvage was successful overall in 93.2% (A: 94.1%; B: 92.6%; P>0.05). Major complications occurred in 9.1%; three patients underwent major amputation (A: n=2; B: n=1). Minor complications were observed in 43.2% of patients (partial flap necrosis, wound dehiscence and non-union; A: 41.2%; B: 44.4%; p>0.05). Overall, 65.9% of patients (A: 64.7%; B: 66.7%; p>0.05) experienced uneventful bone healing, while 18.2% of patients (A: 23.5%; B: 14.8%; p>0.05) experienced delayed healing. Flaps used were mostly musculocutaneous (71.7%). Various assessed demographic characteristics, including age and presence of polytrauma, showed no significant influence on complications (p>0.05). Conclusion  Although there is a significant difference in the time course of externally treated patients with open fractures, prolonged treatment is not associated with a higher complication rate or compromised bone healing outcome. Despite the findings, it is important to avoid delays and strive for interdisciplinary collaboration.

Antibiotics in patients with severe burn injury-A modifiable variable in hypernatremia etiology.

INTRODUCTION: Hypernatremia is a common problem among patients with severe burn injuries and seems to be associated with an unfavorable clinical outcome. The current study was designed to evaluate the impact of antibiotics with a high proportion of sodium on this phenomenon. METHODS: All admissions to our burn center from 01/2017 till 06/2023 were retrospectively screened. All patients aged >18 years which suffered from at least 20 % total body surface burned area (TBSA) 2nd degree burn injuries or more than 10 % TBSA when including areas of 3rd degree burn injuries were included. The course of the serum Na-level was analyzed from two days before till two days after the start of the antibiotic treatment. Ampicillin/sulbactam, cefazoline and piperacillin/tazobactam were classified as high-dose sodium antibiotics (HPS), meropenem and vancomycin as low-dose sodium antibiotics (LPS). RESULTS: 120 patients met the inclusion criteria. A significant increase of the serum Na was detectable in the HPS group on day 1 and 2 after initiating the antibiotic treatment (n = 64, day 1: 2,1 (SD 4,18) mmol/l, p < 0,001; day 2: 2,44 (SD 5,26) mmol/l, p < 0,001) while no significant changes were detectable in the LPS group (n = 21, day 1: 0,18 (SD 7,45) mmol/l, p = 0,91; day 2: -0,27 (SD 7,44) mmol/l, p = 0,87). This effect was further aggravated when analyzing only the HPS patients with a TBSA ≥30 % (n = 33; day 1: 2,93 (SD 4,68) mmol/l, p = 0,002; day 2: 3,41 (SD 5,9) mmol/l, p = 0,003). CONCLUSION: The amount of sodium in antibiotics seems to have a relevant impact on the serum Na during the early stages of severe burn injury. Therefore, this aspect should be taken into account when searching for the most appropriate antibiotic treatment for patients with severe burn injury, especially when being at acute risk for a clinical relevant hypernatremia.

Dissection of Developmental Programs and Regulatory Modules Directing Endosperm Transfer Cell and Aleurone Identity in the Syncytial Endosperm of Barley.

Endosperm development in barley starts with the formation of a multinucleate syncytium, followed by cellularization in the ventral part of the syncytium generating endosperm transfer cells (ETCs) as first differentiating subdomain, whereas aleurone (AL) cells will originate from the periphery of the enclosing syncytium. Positional signaling in the syncytial stage determines cell identity in the cereal endosperm. Here, we performed a morphological analysis and employed laser capture microdissection (LCM)-based RNA-seq of the ETC region and the peripheral syncytium at the onset of cellularization to dissect developmental and regulatory programs directing cell specification in the early endosperm. Transcriptome data revealed domain-specific characteristics and identified two-component signaling (TCS) and hormone activities (auxin, ABA, ethylene) with associated transcription factors (TFs) as the main regulatory links for ETC specification. On the contrary, differential hormone signaling (canonical auxin, gibberellins, cytokinin) and interacting TFs control the duration of the syncytial phase and timing of cellularization of AL initials. Domain-specific expression of candidate genes was validated by in situ hybridization and putative protein-protein interactions were confirmed by split-YFP assays. This is the first transcriptome analysis dissecting syncytial subdomains of cereal seeds and provides an essential framework for initial endosperm differentiation in barley, which is likely also valuable for comparative studies with other cereal crops.

Thermography Supported Color Duplex Ultrasound Accelerates ALT Perforator Imaging.

BACKGROUND: The anterolateral thigh flap is a versatile and dependable perforator flap and is a popular choice in the reconstruction of various body sites. The variable perforator anatomy suggests preoperative perforator imaging to improve safety and speed of dissection. An innovative perforator imaging technique is thermography, which lately gained attention in plastic surgery. METHODS: Thirty-two healthy participants were included in this randomized study. One thigh was examined with dynamic infrared thermography and consecutively with ultrasound, while the contralateral thigh was examined with ultrasound as standalone technology. RESULTS: The application of dynamic infrared thermography prior to ultrasound perforator identification significantly accelerated the ultrasound examination duration by 90 to 130 seconds. The mean duplex ultrasound examination duration correlated positively with the hotspot and perforator quantity per thigh. CONCLUSION: The addition of thermographic perforator mapping can accelerate color duplex ultrasound anterolateral thigh perforator imaging. Furthermore, thermography supplements color duplex ultrasound with crucial information on angiosome location.

The Grasping Test Revisited: A Systematic Review of Functional Recovery in Rat Models of Median Nerve Injury.

The rat median nerve model is a well-established and frequently used model for peripheral nerve injury and repair. The grasping test is the gold-standard to evaluate functional recovery in this model. However, no comprehensive review exists to summarize the course of functional recovery in regard to the lesion type. According to PRISMA-guidelines, research was performed, including the databases PubMed and Web of Science. Groups were: (1) crush injury, (2) transection with end-to-end or with (3) end-to-side coaptation and (4) isogenic or acellular allogenic grafting. Total and respective number, as well as rat strain, type of nerve defect, length of isogenic or acellular allogenic allografts, time at first signs of motor recovery (FSR) and maximal recovery grasping strength (MRGS), were evaluated. In total, 47 articles met the inclusion criteria. Group I showed earliest signs of motor recovery. Slow recovery was observable in group III and in graft length above 25 mm. Isografts recovered faster compared to other grafts. The onset and course of recovery is heavily dependent from the type of nerve injury. The grasping test should be used complementary in addition to other volitional and non-volitional tests. Repetitive examinations should be planned carefully to optimize assessment of valid and reliable data.

The Role of CDK Pathway Dysregulation and Its Therapeutic Potential in Soft Tissue Sarcoma.

Soft tissue sarcomas (STSs) are tumors that are challenging to treat due to their pathologic and molecular heterogeneity and their tumor biology that is not yet fully understood. Recent research indicates that dysregulation of cyclin-dependent kinase (CDK) signaling pathways can be a strong driver of sarcogenesis. CDKs are enzyme forms that play a crucial role in cell-cycle control and transcription. They belong to the protein kinases group and to the serine/threonine kinases subgroup. Recently identified CDK/cyclin complexes and established CDK/cyclin complexes that regulate the cell cycle are involved in the regulation of gene expression through phosphorylation of critical components of transcription and pre-mRNA processing mechanisms. The current and continually growing body of data shows that CDKs play a decisive role in tumor development and are involved in the proliferation and growth of sarcoma cells. Since the abnormal expression or activation of large numbers of CDKs is considered to be characteristic of cancer development and progression, dysregulation of the CDK signaling pathways occurs in many subtypes of STSs. This review discusses how reversal and regulation can be achieved with new therapeutics and summarizes the current evidence from studies regarding CDK modulation for STS treatment.

[Microsurgery Training with a Commercial Smartphone Kit - a new Device]. / Neues, Smartphone-gestütztes mikrochirurgisches Trainingsmodell.

Microsurgical dissection and suturing techniques require persistent practice and perseverance. Rookies in particular often practice on the "dry model" in order to achieve a smooth transition to the application on the patient in the surgical theatre. Whether surgical glove, pig heart, with magnifying glasses, as a virtual reality tool, rat model with or without a training microscope - many different exercise models are described. For a number of years, self-made devices with smartphone cameras as a magnifying aid have also been known and are sometimes used. There is now a new commercial system from the US which allows the trainee to learn basic microsurgical techniques at any time and almost anywhere, or to perfect advanced knotting techniques such as the "through-the-loop" knot relatively easily and inexpensively. For this purpose, a conventional smartphone can be clamped in a 3 D swivel arm and anastomoses can be practiced on various vessel lumens. The smartphone therefor mimics a surgical microscope. There are prefabricated "cards" with built-in small plastic tubes of various diameters (1-3 mm) that can be used for practice.We believe that in the future such training kits can be part of the standard reporting in microsurgical training for interns and students in microsurgical centers.

Technical Note: Novel Use of CytoSorb™ Haemadsorption to Provide Wound Healing Support in Case of Severe Burn Trauma via Reduction of Hyperbilirubinaemia.

Hyperbilirubinaemia has been shown to compromise wound healing in severely burned patients. The therapy options for patients with impairment of wound healing and subsequent severe liver dysfunction are limited. A novel extracorporeal treatment, CytoSorb® (CytoSorbents Corp, USA), is a whole blood adsorber composed of highly biocompatible and porous polystyrene divinylbenzene copolymer beads covered in a polyvinylpyrrolidone coating. It is capable of extracting mainly hydrophobic middle-sized (up to 55 kDa) molecules from blood via size exclusion, including cytokines and bilirubin. We performed therapy with CytoSorb® on a severely burned (48% Total Body Surface Area-TBSA) patient with secondary sclerosing cholangitis (SCC) to promote the wound healing process by reducing bilirubin concentrations and to bridge the time to spontaneous liver regeneration or eventually to liver transplantation after two skin transplantations had failed to provide wound closure. In the first 6 days the cartridge was changed on a daily basis and later after every 2-4 days. The therapy with six adsorbers decreased a total bilirubin concentration from 14.02 to 4.29 mg/dl. By maintaining a stable bilirubin concentration under 5 mg/dl, debridement of abdomen and upper extremities with autologous skin grafting and, 4 weeks later, autologous skin grafting of the back from scrotum and lower extremities were performed successfully. After wound healing had been achieved, the CytoSorb therapy was discontinued after 57 days and 27 adsorber changes. CytoSorb therapy can be a promising support of wound and skin graft healing in patients with severe burns and liver dysfunction due to a significant reduction of total bilirubin concentration.

Tissue-Specific Transcriptome Analysis Reveals Candidate Transcripts Associated with the Process of Programmed B Chromosome Elimination in Aegilops speltoides.

Some eukaryotes exhibit dramatic genome size differences between cells of different organs, resulting from programmed elimination of chromosomes. Here, we present the first transcriptome analysis of programmed chromosome elimination using laser capture microdissection (LCM)-based isolation of the central meristematic region of Aegilops speltoides embryos where B chromosome (B) elimination occurs. The comparative RNA-seq analysis of meristematic cells of embryos with (Bplus) and without Bs (B0) allowed the identification of 14,578 transcript isoforms (35% out of 41,615 analyzed transcript isoforms) that are differentially expressed during the elimination of Bs. A total of 2908 annotated unigenes were found to be up-regulated in Bplus condition. These genes are either associated with the process of B chromosome elimination or with the presence of B chromosomes themselves. GO enrichment analysis categorized up-regulated transcript isoforms into 27 overrepresented terms related to the biological process, nine terms of the molecular function aspect and three terms of the cellular component category. A total of 2726 annotated unigenes were down-regulated in Bplus condition. Based on strict filtering criteria, 341 B-unique transcript isoforms could be identified in central meristematic cells, of which 70 were functionally annotated. Beside others, genes associated with chromosome segregation, kinetochore function and spindle checkpoint activity were retrieved as promising candidates involved in the process of B chromosome elimination.

Barley HISTIDINE KINASE 1 (HvHK1) coordinates transfer cell specification in the young endosperm.

Cereal endosperm represents the most important source of the world's food; nevertheless, the molecular mechanisms underlying cell and tissue differentiation in cereal grains remain poorly understood. Endosperm cellularization commences at the maternal-filial intersection of grains and generates endosperm transfer cells (ETCs), a cell type with a prominent anatomy optimized for efficient nutrient transport. Barley HISTIDINE KINASE1 (HvHK1) was identified as a receptor component with spatially restricted expression in the syncytial endosperm where ETCs emerge. Here, we demonstrate its function in ETC fate acquisition using RNA interference-mediated downregulation of HvHK1. Repression of HvHK1 impairs cell specification in the central ETC region and the development of transfer cell morphology, and consecutively defects differentiation of adjacent endosperm tissues. Coinciding with reduced expression of HvHK1, disturbed cell plate formation and fusion were observed at the initiation of endosperm cellularization, revealing that HvHK1 triggers initial cytokinesis of ETCs. Cell-type-specific RNA sequencing confirmed loss of transfer cell identity, compromised cell wall biogenesis and reduced transport capacities in aberrant cells and elucidated two-component signaling and hormone pathways that are mediated by HvHK1. Gene regulatory network modeling was used to specify the direct targets of HvHK1; this predicted non-canonical auxin signaling elements as the main regulatory links governing cellularization of ETCs, potentially through interaction with type-B response regulators. This work provides clues to previously unknown molecular mechanisms directing ETC specification, a process with fundamental impact on grain yield in cereals.

Laser Capture Microdissection-Based RNA-Seq of Barley Grain Tissues.

Spatiotemporal patterning throughout the plant body depends to a large degree on cell- and tissue-specific expression of genes. Subsequently, for a better understanding of cell and tissue differentiation processes during plant development it is important to conduct transcript analyses in individual cells or tissue types rather than in bulk tissues. Laser capture microdissection (LCM) provides a useful method for isolating specific cell types from complex tissue structures for downstream applications. Contrasting to mammalian cells, the texture of plant cells is more critical due to hard, cellulose-rich cell walls, large vacuoles, and air spaces which complicates tissue preparation and extraction of macromolecules, like DNA and RNA. In particular, developing barley seeds (i.e. grains) depict cell types with differences in osmomolarity (meristematic, differentiating and degenerating tissues) and contain high amounts of the main storage product starch. In this study, we report about methods allowing tissue-specific transcriptome profiling by RNA-seq of developing barley grain tissues from low-input RNA amounts. Details on tissue preparation, laser capture microdissection, RNA isolation, and linear mRNA amplification to produce high-quality samples for Illumina sequencing are provided. Particular emphasis was placed on the influence of the mRNA amplification step on the transcriptome data and the fidelity of deduced expression levels obtained by the developed methods. Analysis of RNA-seq data confirmed sample processing as a highly reliable and reproducible procedure that was also used for transcriptome analyses of different tissue types from barley plants.

Spatiotemporal Dynamics of Oligofructan Metabolism and Suggested Functions in Developing Cereal Grains.

Oligofructans represent one of the most important groups of sucrose-derived water-soluble carbohydrates in the plant kingdom. In cereals, oligofructans accumulate in above ground parts of the plants (stems, leaves, seeds) and their biosynthesis leads to the formation of both types of glycosidic linkages [ß(2,1); ß(2,6)-fructans] or mixed patterns. In recent studies, tissue- and development- specific distribution patterns of the various oligofructan types in cereal grains have been shown, which are possibly related to the different phases of grain development, such as cellular differentiation of grain tissues and storage product accumulation. Here, we summarize the current knowledge about oligofructan biosynthesis and accumulation kinetics in cereal grains. We focus on the spatiotemporal dynamics and regulation of oligofructan biosynthesis and accumulation in developing barley grains (deduced from a combination of metabolite, transcript and proteome analyses). Finally, putative physiological functions of oligofructans in developing grains are discussed.

Spatio-temporal dynamics of fructan metabolism in developing barley grains.

Barley (Hordeum vulgare) grain development follows a series of defined morphological and physiological stages and depends on the supply of assimilates (mainly sucrose) from the mother plant. Here, spatio-temporal patterns of sugar distributions were investigated by mass spectrometric imaging, targeted metabolite analyses, and transcript profiling of microdissected grain tissues. Distinct spatio-temporal sugar balances were observed, which may relate to differentiation and grain filling processes. Notably, various types of oligofructans showed specific distribution patterns. Levan- and graminan-type oligofructans were synthesized in the cellularized endosperm prior to the commencement of starch biosynthesis, while during the storage phase, inulin-type oligofructans accumulated to a high concentration in and around the nascent endosperm cavity. In the shrunken endosperm mutant seg8, with a decreased sucrose flux toward the endosperm, fructan accumulation was impaired. The tight partitioning of oligofructan biosynthesis hints at distinct functions of the various fructan types in the young endosperm prior to starch accumulation and in the endosperm transfer cells that accomplish the assimilate supply toward the endosperm at the storage phase.

Caspase-like activities accompany programmed cell death events in developing barley grains.

Programmed cell death is essential part of development and cell homeostasis of any multicellular organism. We have analyzed programmed cell death in developing barley caryopsis at histological, biochemical and molecular level. Caspase-1, -3, -4, -6 and -8-like activities increased with aging of pericarp coinciding with abundance of TUNEL positive nuclei and expression of HvVPE4 and HvPhS2 genes in the tissue. TUNEL-positive nuclei were also detected in nucellus and nucellar projection as well as in embryo surrounding region during early caryopsis development. Quantitative RT-PCR analysis of micro-dissected grain tissues revealed the expression of HvVPE2a, HvVPE2b, HvVPE2d, HvPhS2 and HvPhS3 genes exclusively in the nucellus/nucellar projection. The first increase in cascade of caspase-1, -3, -4, -6 and -8-like activities in the endosperm fraction may be related to programmed cell death in the nucellus and nucellar projection. The second increase of all above caspase-like activities including of caspase-9-like was detected in the maturating endosperm and coincided with expression of HvVPE1 and HvPhS1 genes as well as with degeneration of nuclei in starchy endosperm and transfer cells. The distribution of the TUNEL-positive nuclei, tissues-specific expression of genes encoding proteases with potential caspase activities and cascades of caspase-like activities suggest that each seed tissue follows individual pattern of development and disintegration, which however harmonizes with growth of the other tissues in order to achieve proper caryopsis development.

Gibberellin-to-abscisic acid balances govern development and differentiation of the nucellar projection of barley grains.

In cereal grains, the maternal nucellar projection (NP) constitutes the link to the filial organs, forming a transfer path for assimilates and signals towards the endosperm. At transition to the storage phase, the NP of barley (Hordeum vulgare) undergoes dynamic and regulated differentiation forming a characteristic pattern of proliferating, elongating, and disintegrating cells. Immunolocalization revealed that abscisic acid (ABA) is abundant in early non-elongated but not in differentiated NP cells. In the maternally affected shrunken-endosperm mutant seg8, NP cells did not elongate and ABA remained abundant. The amounts of the bioactive forms of gibberellins (GAs) as well as their biosynthetic precursors were strongly and transiently increased in wild-type caryopses during the transition and early storage phases. In seg8, this increase was delayed and less pronounced together with deregulated gene expression of specific ABA and GA biosynthetic genes. We concluded that differentiation of the barley NP is driven by a distinct and specific shift from lower to higher GA:ABA ratios and that the spatial-temporal change of GA:ABA balances is required to form the differentiation gradient, which is a prerequisite for ordered transfer processes through the NP. Deregulated ABA:GA balances in seg8 impair the differentiation of the NP and potentially compromise transfer of signals and assimilates, resulting in aberrant endosperm growth. These results highlight the impact of hormonal balances on the proper release of assimilates from maternal to filial organs and provide new insights into maternal effects on endosperm differentiation and growth of barley grains.

Development of endosperm transfer cells in barley.

Endosperm transfer cells (ETCs) are positioned at the intersection of maternal and filial tissues in seeds of cereals and represent a bottleneck for apoplasmic transport of assimilates into the endosperm. Endosperm cellularization starts at the maternal-filial boundary and generates the highly specialized ETCs. During differentiation barley ETCs develop characteristic flange-like wall ingrowths to facilitate effective nutrient transfer. A comprehensive morphological analysis depicted distinct developmental time points in establishment of transfer cell (TC) morphology and revealed intracellular changes possibly associated with cell wall metabolism. Embedded inside the grain, ETCs are barely accessible by manual preparation. To get tissue-specific information about ETC specification and differentiation, laser microdissection (LM)-based methods were used for transcript and metabolite profiling. Transcriptome analysis of ETCs at different developmental stages by microarrays indicated activated gene expression programs related to control of cell proliferation and cell shape, cell wall and carbohydrate metabolism reflecting the morphological changes during early ETC development. Transporter genes reveal distinct expression patterns suggesting a switch from active to passive modes of nutrient uptake with the onset of grain filling. Tissue-specific RNA-seq of the differentiating ETC region from the syncytial stage until functionality in nutrient transfer identified a high number of novel transcripts putatively involved in ETC differentiation. An essential role for two-component signaling (TCS) pathways in ETC development of barley emerged from this analysis. Correlative data provide evidence for abscisic acid and ethylene influences on ETC differentiation and hint at a crosstalk between hormone signal transduction and TCS phosphorelays. Collectively, the data expose a comprehensive view on ETC development, associated pathways and identified candidate genes for ETC specification.