"Improved quality assessment of cornelian cherry (Cornus mas L.) fruit with regard to their processing potential"

The sensory properties and appropriateness of cornelian cherry (Cornus mas L.) for processing is very closely related to its ripening stage, recognizable by firmness and skin colour to some extent. Due to the non-uniform ripening on the trees the quality of the fruits offered on the market depends very much on the harvest-method. Today, processors, who usually do not buy fresh fruits but frozen fruits or puree on the market, don`t have a suitable means for the accurate quality assessment of the raw material they need for the processing of high-quality products. The results of this work show for the first time that from the selected parameters (carbohydrates, organic acids, phenols) only flavonols, especially kaempferol-3-glucoside is appropriate to determine the stage of ripeness of cornelian cherries properly independent from species, provenance and crop year. Kaempferol 3-O-glucoside of about 1.75 mg/Kg in wild genotypes and of about 0.80 mg/Kg in most big cornelian cherry species can serve as a reference for sufficient ripeness and therefore for high fruit quality.

Stability of self-reported psychopathic traits in at-risk adolescents in youth welfare and juvenile justice institutions

BACKGROUND

The purpose of this study was to evaluate the self-reported stability of psychopathic traits in adolescents in residential care (both child welfare and juvenile justice placed juveniles) and potential influencing factors.

METHODS

We applied the Youth Psychopathic traits Inventory (YPI) in a sample of 162 adolescents (M = 15.0 years, SD = 1.3) over a mean time interval of 11 months (min. 6, max. 21 months, SD = 3.14).

RESULTS

There was no significant difference in YPI total score nor in the three underlying dimensions Grandiose-Manipulative (GM), Callous-Unemotional (CU), and Impulsive-Irresponsible (II) between t1 and t2. Furthermore, approximately 70% of the adolescents showed no clinically significant reliable change on the YPI total score (as measured with the reliable change index), 15% improved, 15% deteriorated. The strongest predictor for psychopathic traits at t2 were psychopathic traits at t1. Additional predictors for higher levels of general psychopathic traits was male sex, for CU-traits male sex and lower levels of internalizing mental health problems, and for II-traits higher levels of externalizing mental health problems. Generally, the three reliable change groups (increase, no change, decrease) did not seemed to differ on relevant factors.

CONCLUSIONS

Our results add to the findings that psychopathic traits are relatively stable in this at-risk group over approximately a 1-year time interval. Research with a longer follow-up time and more time points is warranted to better interpret these results.

ATRT-16. Mechanisms of myeloid cell-induced resistance in AT/RT

INTRODUCTION: Atypical teratoid/rhabdoid tumor (AT/RT) is a primary pediatric tumor entity of the central nervous system showing intra- and intertumoral heterogeneity concerning the molecular landscape and cellular composition. Myeloid cells are considered key orchestrators of the immunological tumor microenvironment (TME) of AT/RT. Tumor-infiltrating CD68+ macrophages favor chemotherapy resistance and recurrence, and are consequently related to a poor patient outcome. METHODS: Using single-cell RNA sequencing (scRNA-seq) of human and murine AT/RT samples, multiplex immunohistochemistry, depletion of myeloid cells in mouse models and advanced cell culture models for myeloid tumor cell communication, we obtained deeper mechanistic insight into these cell-cell interactions. RESULTS: Infiltrating CD68+ macrophages interact with AT/RT tumor cells generating intermediary hybrid-like cells with autonomous communication properties, increasing the cell heterogeneity of AT/RT. By depletion of myeloid cells in AT/RT mouse models followed by scRNA-seq of tumor and non-tumor samples, we demonstrated that tumor formation is hindered. Furthermore, we give mechanistic insights into how myeloid cells contribute to tumorigenesis. IN CONCLUSION: the dynamic and extensive interactions between tumor cells and myeloid cells do not only potentiate cellular heterogeneity but might also induce cellular plasticity associated with the acquisition of resistance to chemotherapy and seem to be essential for AT/RT development.

ATRT-15. Primordial germ cells identified as one potential cell of origin of MYC rhabdoid tumors

Rhabdoid tumors (RT) are embryonal neoplasms occurring most frequently in the central nervous system where they are termed atypical teratoid rhabdoid tumor (ATRT). A common hallmark of RT is homozygous loss of the BAF complex subunit SMARCB1. RT patients have a poor prognosis with an overall survival time of 17 months and >60% of patients suffer from relapses. The lack of an optimal treatment strategy could be attributed to the heterogeneity within and between different subgroups of ATRT. Despite the recent advancements in characterizing RT at a molecular level, the cellular origin of RT remains elusive. Thus, this study focused on the identification of the cellular origin of MYC-RT and underlying epigenetic deregulations which account for the cellular heterogeneity in these tumors. We showed that Smarcb1 abrogation in Sox2-positive progenitor cells at E6.5 give rise to RT of the MYC and SHH subgroup in genetically engineered mouse models (GEMM). To uncover distinct cells of origin (COO) for the SHH and MYC subgroups, unbiased computational approaches were used to compare single-cell transcriptomes of GEMMs with single-cell reference maps of murine early embryogenesis. While SHH tumors arise from mid/hindbrain progenitor cells, primordial germ cells (PGCs) emerge as COO of both intracranial and extracranial MYC tumors. PGCs as COO of MYC-RT were validated in vivo by using PGC-specific Smarcb1 knockout mouse model. We further characterized a deregulated transcriptome in MYC-RT compared to PGCs, which is sustained by a subset of epigenetically driven tumor cells. Deregulated expression of genes driving methylation/demethylation processes in MYC tumors and regression of these tumors upon treatment with decitabine in vitro and in vivo, indicates that DNA methylation plays a key role in cellular transformation and development of MYC-RT.

ETMR-05. Single-cell transcriptomics of ETMR reveals developmental cellular programs and tumor-pericyte communications in the microenvironment

BACKGROUND: Embryonal tumors with multilayered rosettes (ETMR) are pediatric brain tumors bearing a grim prognosis, despite intensive multimodal therapeutic approaches. Insights into cellular heterogeneity and cellular communication of tumor cells with cells of the tumor microenvironment (TME), by applying single-cell (sc) techniques, potentially identify mechanisms of therapy resistance and target-directed treatment approaches. MATERIAL AND METHODS: To explore ETMR cell diversity, we used single-cell RNA sequencing (scRNA-seq) in human (n=2) and murine ETMR (transgenic mode; n=4) samples, spatial transcriptomics, 2D and 3D cultures (including co-cultures with TME cells), multiplex immunohistochemistry and drug screens. RESULTS: ETMR microenvironment is composed of tumor and non-tumor cell types. The ETMR malignant compartment harbour cells representing distinct transcriptional metaprograms, (NSC-like, NProg-like and Neuroblast-like), mirroring embryonic neurogenic cell states and fuelled by neurogenic pathways (WNT, SHH, Hippo). The ETMR TME is composed of oligodendrocyte and neuronal progenitor cells, neuroblasts, microglia, and pericytes. Tumor-specific ligand-receptor interaction analysis showed enrichment of intercellular communication between NProg-like ETMR cells and pericytes (PC). Functional network analyses reveal ETMR-PC interactions related to stem-cell signalling and extracellular matrix (ECM) organization, involving factors of the WNT, BMP, and CxCl12 networks. Results from ETMR-PC co-culture and spatial transcriptomics pointed to a pivotal role of pericytes in keeping ETMR in a germinal neurogenic state, enriched in stem-cell signalling. Drug screening considering cellular heterogeneity and cellular communication suggested novel therapeutic approaches. CONCLUSION: ETMR demonstrated diversity in the microenvironment, with enrichment of cell-cell communications with pericytes, supporting stem-cell signalling and interfering in the organization of the tumor extracellular matrix. Targeting ETMR-PC interactions might bring new opportunities for target-directed therapy.

Single-cell transcriptomics identifies potential cells of origin of MYC rhabdoid tumors

Rhabdoid tumors (RT) are rare and highly aggressive pediatric neoplasms. Their epigenetically-driven intertumoral heterogeneity is well described; however, the cellular origin of RT remains an enigma. Here, we establish and characterize different genetically engineered mouse models driven under the control of distinct promoters and being active in early progenitor cell types with diverse embryonic onsets. From all models only Sox2-positive progenitor cells give rise to murine RT. Using single-cell analyses, we identify distinct cells of origin for the SHH and MYC subgroups of RT, rooting in early stages of embryogenesis. Intra- and extracranial MYC tumors harbor common genetic programs and potentially originate from fetal primordial germ cells (PGCs). Using PGC specific Smarcb1 knockout mouse models we validate that MYC RT originate from these progenitor cells. We uncover an epigenetic imbalance in MYC tumors compared to PGCs being sustained by epigenetically-driven subpopulations. Importantly, treatments with the DNA demethylating agent decitabine successfully impair tumor growth in vitro and in vivo. In summary, our work sheds light on the origin of RT and supports the clinical relevance of DNA methyltransferase inhibitors against this disease.

Rhabdoid tumors (RT) are aggressive paediatric cancers with yet unknown cells of origin. Here, the authors establish genetically engineered mouse models of RT and, using single-cell RNA-seq and epigenomics, identify potential cells of origin for the SHH and MYC subtypes.

POS0183 SIGLEC1 AS A TYPE I INTERFERON BIOMARKER IN IDIOPATHIC INFLAMMATORY MYOPATHIES

Background:

Idiopathic inflammatory myopathies (IIM) are autoimmune diseases that mainly affect skeletal muscle, lung, skin and joints. IIM can be separated into dermatomyositis (DM), inclusion body myositis (IBM), antisynthetase syndrome (AS) and immune-mediated necrotizing myopathy (IMNM). Type I interferons (IFN) are known to play a crucial role in the etiopathogenesis of some of these entities such as DM.[1] Sialic acid binding Ig-like lectin 1 (SIGLEC1, CD169) is part of the type I IFN signature found in SLE and DM and is expressed on the cell surface of monocytes. Thus, analysis of SIGLEC1 expression by flow cytometry enables a straightforward assessment of the type I IFN signature. Its utility has been shown for juvenile and adult SLE and other rheumatic diseases but not in IIM.[2,3] The assessment of the type I IFN system in clinical practice is an unmet need and, in this context, SIGLEC1 might be useful.

Objectives:

To assess SIGLEC1 expression on monocytes by flow cytometry as a type I IFN biomarker in IIM

Methods:

Pediatric and adult patients with a clinical diagnosis of DM, AS, IMNM and IBM and at least one measurement of SIGLEC1 who have been treated at the Department of Rheumatology, Charité - Universitätsmedizin Berlin between 2015 and 2020 were included in this retrospective study. Control groups of healthy individuals (n=19) and SLE patients (n=30) were included. Disease activity was assessed by Physician Global Assessment (PGA) and Childhood Myositis Assessment Scale (CMAS). SIGLEC1 expression on monocytes was analyzed by flow cytometry. Cross-sectional analyses (n=74) were performed using Mann Whitney-U test (MWU) and two-level mixed-effects linear regression model was used for longitudinal analyses (n=26, 110 visits). This study was approved by the local ethics committee of the Charité - Universitätsmedizin Berlin.

Results:

74 patients (adult/juvenile DM: n=21/n=17; AS: n=19; IMNM: n=8; IBM: n=9) were included. In cross-sectional analysis, SIGLEC1 expression was significantly upregulated in adult and juvenile DM patients with moderate to severe disease activity (PGA≥5) compared with adult/juvenile DM patients with no to moderate disease activity (PGA<5) (both p<0.001). In longitudinal analyses, SIGLEC1 correlated with disease activity in juvenile DM (SIGLEC1 vs. CMAS: betaST=-0.65; p<0.001) and adult DM (SIGLEC1 vs. PGA: betaST=0.52; p<0.001), better than Creatine Kinase (CK) (juvenile DM, CK vs. CMAS: betaST=-0.50; p<0.001; adult DM, CK vs PGA: betaST=0.17; p=0.149). In AS 42,1% of the patients showed elevated SIGLEC1 expression, while it was not upregulated in IMNM and only in two patients with IBM, who were concurrently positive for autoantibodies that affect the type I IFN system (see Figure 1).

Conclusion:

SIGLEC1 is a useful biomarker to identify an activated type I IFN system in IIM. Flow cytometry is used widely in laboratory medicine, which could facilitate the implementation of SIGLEC1 into clinical routine.

References:

[1]Gallay L, Mouchiroud G, Chazaud B. Interferon-signature in idiopathic inflammatory myopathies: Current Opinion in Rheumatology 2019;31:634–42. doi:10.1097/BOR.0000000000000653

[2]Rose T, Grutzkau A, Hirseland H, et al. IFNalpha and its response proteins, IP-10 and SIGLEC-1, are biomarkers of disease activity in systemic lupus erythematosus. Ann Rheum Dis 2013;72:1639–45. doi:10.1136/annrheumdis-2012-201586

[3]Stuckrad SL von, Klotsche J, Biesen R, et al. SIGLEC1 (CD169) is a sensitive biomarker for the deterioration of the clinical course in childhood systemic lupus erythematosus. Lupus 2020;:961203320965699. doi:10.1177/0961203320965699

Figure 1.

SIGLEC1 expression on monocytes in IIM subgroups and control groups; in IIM subgroups, patients with low disease activity (PGA<5) are marked in blue, patients with high disease activity (PGA≥5) are marked in red; mAb/cell, monoclonal antibodies bound per cell

Disclosure of Interests:

None declared

An extracellular vesicle-related gene expression signature identifies high-risk patients in medulloblastoma

BACKGROUND

Medulloblastoma (MB) is a malignant brain tumor in childhood. It comprises 4 subgroups with different clinical behaviors. The aim of this study was to characterize the transcriptomic landscape of MB, both at the level of individual tumors as well as in large patient cohorts.

METHODS

We used a combination of single-cell transcriptomics, cell culture models and biophysical methods such as nanoparticle tracking analysis and electron microscopy to investigate intercellular communication in the MB tumor niche.

RESULTS

Tumor cells of the sonic hedgehog (SHH)-MB subgroup show a differentiation blockade. These cells undergo extensive metabolic reprogramming. The gene expression profiles of individual tumor cells show a partial convergence with those of tumor-associated glial and immune cells. One possible cause is the transfer of extracellular vesicles (EVs) between cells in the tumor niche. We were able to detect EVs in co-culture models of MB tumor cells and oligodendrocytes. We also identified a gene expression signature, EVS, which shows overlap with the proteome profile of large oncosomes from prostate cancer cells. This signature is also present in MB patient samples. A high EVS expression is one common characteristic of tumors that occur in high-risk patients from different MB subgroups or subtypes.

CONCLUSIONS

With EVS, our study uncovered a novel gene expression signature that has a high prognostic significance across MB subgroups.

ATRT-13. DIFFERENT CELLS OF ORIGIN PAVE THE WAY FOR MOLECULAR HETEROGENEITY IN RHABDOID TUMORS

Rhabdoid tumors (RT) are rare but highly aggressive pediatric neoplasms. These tumors carry homozygous loss-of-function alterations of SMARCB1 in almost all cases with an otherwise low mutational load. RT arise at different intracranial (ATRT) as well as extracranial (MRT) anatomical sites. Three main molecular subgroups (ATRT-SHH, ATRT-TYR, ATRT-MYC) have been characterized for ATRT which are epigenetically and clinically diverse, while MRT show remarkable similarities with ATRT-MYC distinct from ATRT-SHH and ATRT-TYR. Even though there are hypotheses about various cells of origin among RT subgroups, precursor cells of RT have not yet been identified. Previous studies on the temporal control of SMARCB1 knockout in genetically engineered mouse models have unveiled a tight vulnerable time frame during embryogenesis with regard to the susceptibility of precursor cells to result in RT. In this study, we employed single-cell RNA sequencing to describe the intra- and intertumoral heterogeneity of murine ATRT-SHH and -MYC as well as extracranial MYC tumor cells. We defined subgroup-specific tumor markers for all RT classes but also observed a notable overlap of gene expression patterns in all MYC subgroups. By comparing these single-cell transcriptomes with available single-cell maps of early embryogenesis, we gained first insights into the cellular origin of RT. Finally, unsupervised clustering of published human RT methylation data and healthy control tissues confirmed the existence of different cells of origin for intracranial SHH tumors and MYC tumors independent of their anatomical localizations.

ATRT-14. MACROPHAGE-TUMOR CELL INTERACTION PROMOTES ATRT PROGRESSION AND CHEMORESISTANCE

Atypical teratoid/rhabdoid tumors (ATRT) are pediatric brain neoplasms that are known for their heterogeneity concerning pathophysiology and outcome. The three genetically rather uniform but epigenetically distinct molecular subgroups of ATRT alone do not sufficiently explain the clinical heterogeneity. Therefore, we examined the tumor microenvironment (TME) in the context of tumor diversity. By using multiplex-immunofluorescent staining and single-cell RNA sequencing (scRNA-seq) we unveiled the pan-macrophage marker CD68 as a subgroup-independent negative prognostic marker for survival of ATRT patients. ScRNA-seq analysis of murine ATRT-SHH, ATRT-MYC and extracranial RT (eRT) provide a delineation of the TME, which is predominantly infiltrated by myeloid cells: more specifically a microglia-enriched niche in ATRT-SHH and a bone marrow-derived macrophage infiltration in ATRT-MYC and eRT. Exploring the cell-cell communication of tumor cells with tumor-associated immune cells, we found that Cd68+ tumor-associated macrophages (TAMs) are central to intercellular communication with tumor cells. Moreover, we uncovered distinct tumor phenotypes in murine ATRT-MYC that share genetic traits with TAMs. These intermediary cells considerably increase the intratumoral heterogeneity of ATRT-MYC tumors. In vitro co-culture experiments recapitulated the capability of ATRT-MYC cells to interchange cell material with macrophages extensively, in contrast to ATRT-SHH cells. We found that microglia are less involved in the exchange of information with ATRT cells and that direct contact is a prerequisite for incorporation. A relapse xenograft model implied that intermediary cells are involved in the acquisition of chemotherapy resistance. We show evidence that TAM-tumor cell interaction is one mechanism of chemotherapy resistance and relapse in ATRT.

ETMR-05. SINGLE-CELL RNA-SEQ OF ETMR REVEALS CELL PROGRAMS OF DEVELOPMENTAL HIERARCHY AND CELLULAR DIVERSITY IN THE TUMOR MICROENVIRONMENT

Embryonal tumors with multilayered rosettes (ETMR) are deadly brain malignancies affecting young children. No standard treatment is available and the median survival is less than 12 months. Molecularly, the disease is characterized by the miRNA C19MC cluster amplification, with the expression of multiples miRNAs related to a stem cell program. The discoveries on the purely molecular mechanisms of the disease did not help to create a bridge for new treatment strategies so far and the cellular diversity of ETMR remains poorly understood. In this study, we used single-cell RNA sequencing of murine and human tumors to describe ETMR cellular heterogeneity. Our findings support that intra-tumoral heterogeneity is mainly characterized by 4 cellular programs defining a developmental hierarchy related to different metabolic states: 1) Early quiescent NSC-like cells supported by fatty-acid oxidation 2) Late NSC and NP-like proliferative cells fueled by glycolytic metabolism; 3) Post-mitotic neuroblast-like cells, relying on oxidative-phosphorylation; 4) NSC-like proliferative cells, with metabolic plasticity and capable of performing the three types of metabolism. Tumor-specific ligand-receptor interaction analysis revealed that ETMR exchange with microglia and vascular mural cells (MC) signals related to extracellular matrix (ECM) organization (Cxcl12-CxCr4), stem cell signaling (BMPs-BMP receptors), anti-apoptosis and survival (Ntf3-Ntrk), not seen in the control brain. In addition, the vascular MC showed a cancer-associated fibroblast (CAF) phenotype, with potential prognostic implications, as previously demonstrated for other tumors. This study provides new findings to build up a more robust understanding of ETMR biology and opens space for further studies in the field.

A vanishing dynamic capillarity limit equation with discontinuous flux

We prove existence and uniqueness of a solution to the Cauchy problem corresponding to the dynamics capillarity equation ∂ t u ε , δ + div f ε , δ ( x , u ε , δ ) = ε Δ u ε , δ + δ ( ε ) ∂ t Δ u ε , δ , x ∈ M , t ≥ 0 u | t = 0 = u 0 ( x ) . Here, f ε , δ and u 0 are smooth functions while ε and δ = δ ( ε ) are fixed constants. Assuming f ε , δ → f ∈ L p ( R d × R ; R d ) for some 1 < p < ∞ , strongly as ε → 0 , we prove that, under an appropriate relationship between ε and δ ( ε ) depending on the regularity of the flux f , the sequence of solutions ( u ε , δ ) strongly converges in L loc 1 ( R + × R d ) toward a solution to the conservation law ∂ t u + div f ( x , u ) = 0 . The main tools employed in the proof are the Leray-Schauder fixed point theorem for the first part and reduction to the kinetic formulation combined with recent results in the velocity averaging theory for the second. These results have the potential to generate a stable semigroup of solutions to the underlying scalar conservation laws different from the Kruzhkov entropy solutions concept.

The Heparan Sulfate Sulfotransferases HS2ST1 and HS3ST2 Are Novel Regulators of Breast Cancer Stem-Cell Properties

Heparan sulfate (HS) is a glycosaminoglycan found mainly in its protein-conjugated form at the cell surface and the extracellular matrix. Its high sulfation degree mediates functional interactions with positively charged amino acids in proteins. 2-O sulfation of iduronic acid and 3-O sulfation of glucosamine in HS are mediated by the sulfotransferases HS2ST and HS3ST, respectively, which are dysregulated in several cancers. Both sulfotransferases regulate breast cancer cell viability and invasion, but their role in cancer stem cells (CSCs) is unknown. Breast CSCs express characteristic markers such as CD44⁺/CD24^−/low, CD133 and ALDH1 and are involved in tumor initiation, formation, and recurrence. We studied the influence of HS2ST1 and HS3ST2 overexpression on the CSC phenotype in breast cancer cell lines representative of the triple-negative (MDA-MB-231) and hormone-receptor positive subtype (MCF-7). The CD44⁺/CD24^−/low phenotype was significantly reduced in MDA-MB-231 cells after overexpression of both enzymes, remaining unaltered in MCF-7 cells. ALDH1 activity was increased after HS2ST1 and HS3ST2 overexpression in MDA-MB-231 cells and reduced after HS2ST1 overexpression in MCF-7 cells. Colony and spheroid formation were increased after HS2ST1 and HS3ST2 overexpression in MCF-7 cells. Moreover, MDA-MB-231 cells overexpressing HS2ST1 formed more colonies and could not generate spheres. The phenotypic changes were associated with complex changes in the expression of the stemness-associated notch and Wnt-signaling pathways constituents, syndecans, heparanase and Sulf1. The results improve our understanding of breast CSC function and mark a subtype-specific impact of HS modifications on the CSC phenotype of triple-negative and hormone receptor positive breast cancer model cell lines.

Macrophage-tumor cell interaction promotes ATRT progression and chemoresistance

Atypical teratoid/rhabdoid tumors (ATRT) are known for their heterogeneity concerning pathophysiology and outcome. However, predictive factors within distinct subgroups still need to be uncovered. Using multiplex immunofluorescent staining and single-cell RNA sequencing we unraveled distinct compositions of the immunological tumor microenvironment (TME) across ATRT subgroups. CD68⁺ cells predominantly infiltrate ATRT-SHH and ATRT-MYC and are a negative prognostic factor for patients' survival. Within the murine ATRT-MYC and ATRT-SHH TME, Cd68⁺ macrophages are core to intercellular communication with tumor cells. In ATRT-MYC distinct tumor cell phenotypes express macrophage marker genes. These cells are involved in the acquisition of chemotherapy resistance in our relapse xenograft mouse model. In conclusion, the tumor cell-macrophage interaction contributes to ATRT-MYC heterogeneity and potentially to tumor recurrence.

Choice of factors and medium impinge on success of ESC to TSC conversion

INTRODUCTION

The first lineage separation in mammalian development occurs when totipotent cells of the zygote give rise to the inner cell mass and the trophectoderm. The lineages are strictly separated by an epigenetic barrier. In vitro derivatives of these lineages embryonic stem cells (ESC) and trophoblast stem cells (TSC) are used to study the requirements needed to overcome the barrier in ESC to TSC conversion approaches.

METHODS

Different combinations of TSC transcription factors were induced in ESC for three days. Cells were kept in TS medium with fetal bovine serum (FBS) or the chemically defined TX medium. Obtained cells were analysed for OCT4 levels, TSC surface marker levels, expression of TSC markers and methylation status of Elf5, Oct4 and Nanog promoters. Further, long-term culture stability and in vitro and in vivo differentiation was tested.

RESULTS

Overexpression of Gata3, Eomes, Tfap2c, Ets2 and Cdx2 in ESC resulted in induction of TSC fate. Overexpression of Cdx2 or four factors (Gata3, Eomes, Tfap2c and Ets2) resulted in complete conversion only when cells were cultured in TX medium. The obtained induced TSC (iTSC) display characteristics of bona fide TSC in terms of marker expression and promoter methylation patterns. The generated converted cells were shown to display self-renewal and to be capable to differentiate into TSC derivatives in vitro and in vivo.

CONCLUSION

Gata3, Eomes, Tfap2c, Ets2 and Cdx2 overexpression in ESC resulted in stable iTSC fate independent of culture conditions. For four factors or Cdx2 alone, TX medium is required for complete TSC conversion.

Tibial nailing using a suprapatellar rather than an infrapatellar approach significantly reduces anterior knee pain postoperatively: a multicentre clinical trial

AIMS

The aim of this study was to compare the incidence of anterior knee pain after antegrade tibial nailing using suprapatellar and infrapatellar surgical approaches.

PATIENTS AND METHODS

A total of 95 patients with a tibial fracture requiring an intramedullary nail were randomized to treatment using a supra- or infrapatellar approach. Anterior knee pain was assessed at four and six months, and one year postoperatively, using the Aberdeen Weightbearing Test - Knee (AWT-K) score and a visual analogue scale (VAS) score for pain. The AWT-K is an objective patient-reported outcome measure that uses weight transmitted through the knee when kneeling as a surrogate for anterior knee pain.

RESULTS

A total of 53 patients were randomized to a suprapatellar approach and 42 to an infrapatellar approach. AWT-K results showed a greater mean proportion of weight transmitted through the injured leg compared with the uninjured leg when kneeling in the suprapatellar group compared with the infrapatellar group at all timepoints at all follow-up visits. This reached significance at four months for all timepoints except 30 seconds. It also reached significance at six months at 0 seconds, and for one year at 60 seconds.

CONCLUSION

The suprapatellar surgical approach for antegrade tibial nailing is associated with less anterior knee pain postoperatively compared with the infrapatellar approach Cite this article: Bone Joint J 2019;101-B:1138-1143.

Metal-organic framework nanoparticles for arsenic trioxide drug delivery

Arsenic trioxide is a double-edged sword: On the one hand it is known as a poison, on the other hand it is used as an anticancer drug. Though effective in the treatment of leukaemia, arsenic trioxide has not been able to be introduced into the treatment of solid tumour entities yet due to its dose-limiting toxicity. However, different in vitro and in vivo studies revealed arsenic trioxide to be a potent agent against different solid tumour entities, including atypical teratoid rhabdoid tumours (ATRT), a paediatric brain tumour entity with a very poor prognosis. To improve the pharmacokinetics and therapeutic efficacy of arsenic trioxide and to reduce its toxic side effects, we propose to use a metal-organic framework (MOF) as a drug carrier material. Herein we report on using a MOF called MFU-4l (Metal-Organic Framework Ulm University), consisting of Zn(ii) ions and bis(1H-1,2,3-triazolo[4,5-b],[4',5'-i])dibenzo[1,4]dioxin ligands, to deliver arsenic trioxide in a form of dihydrogen arsenite anions. The H₂AsO₃ ^- anions were introduced to the MOF in a nanoparticle formulation via a postsynthetic side ligand exchange. The prepared material was characterised by IR, TGA, XRPD, SEM-EDX, TEM, DLS, ICP-OES and adsorption analysis. The drug release studies at different pH values were carried out as well as cytotoxicity tests with different ATRT cell lines and non-tumorous-control cell lines. The MOF-based material was shown to be a promising candidate for arsenic trioxide drug delivery.

Driving Ability and Psychotropic Drugs: Legal Framework, Forensic Aspects

Although the rate of victims of road traffic accidents is already relatively low in Switzerland compared to other western countries, still 253 people died in 2015. The Swiss parliament therefore issued in 2012 already a program called “Via secura” to increase road traffic security by means of a package of measures, ranging from immobilizing systems for the car in case of drunken drivers to stricter rules for medical assessment of ability to drive a car and better training for doctors in such assessment to finally stricter laws regarding lower tolerance for alcohol levels and zero tolerance for drug consumption when driving a car. The presentation will focus on changes in legal regulation for both medical assessment as well as rules for alcohol or drug consumption when driving a car. Positive and negative consequences for the field of forensic psychiatry are discussed.

Disclosure of interest

The author declares that he has no competing interest.

Orientation Congruency Effects for Familiar Objects

How do observers recognize objects after spatial transformations? Recent neurocomputational models have proposed that object recognition is based on coordinate transformations that align memory and stimulus representations. If the recognition of a misoriented object is achieved by adjusting a coordinate system (or reference frame), then recognition should be facilitated when the object is preceded by a different object in the same orientation. In the two experiments reported here, two objects were presented in brief masked displays that were in close temporal contiguity; the objects were in either congruent or incongruent picture-plane orientations. Results showed that naming accuracy was higher for congruent than for incongruent orientations. The congruency effect was independent of superordinate category membership (Experiment 1) and was found for objects with different main axes of elongation (Experiment 2). The results indicate congruency effects for common familiar objects even when they have dissimilar shapes. These findings are compatible with models in which object recognition is achieved by an adjustment of a perceptual coordinate system.

Preparation of photochromic paper, using fibre-attached spiropyran polymer networks

Spiropyran-based photochromic paper was prepared by covalent immobilisation of functional polymer networks. The sensitivity of the UV-induced colour change was dynamically adjusted by a damping method. Thereby, a colourimetric UV sensor was designed.

High Estradiol Levels During Postmenopause - Pitfalls in Laboratory Analysis

A 54-year-old woman was admitted with a result of high serum estradiol levels (> 4300 pg/ml) and typical postmenopausal symptoms. She had a history of an adnexectomy (normal histopathology) due to the elevated estradiol levels. After surgery, estradiol levels were as high as before. Analyzing the anti-mullerian hormone (AMH), inhibin B, DHEA-S and estrone, typical postmenopausal levels were found. Serum estradiol levels were controlled several times with rabbit-derived polyclonal as well as monoclonal antibodies to optimize the selectivity of the test system. Secondary, a radioimmunoassay was performed to exclude interferences of the detection system where lower, but still elevated estradiol levels (186 pg/ml) were found. Hypothesizing that our patient underwent a cross reaction with irregular antibodies, a control was done using sheep-derived antibodies, which proved a postmenopausal hormone level (estradiol level < 5 pg/ml). This result was confirmed using a fluorescence enzyme immunoassay (FEIA) revealing high levels of irregular antibodies (> 200 mg/l; reference < 30 mg/l). This case depicts the pitfalls of estradiol measurement detecting false elevated estradiol levels in a postmenopausal woman.

Surface Influences on the Electrodiffusive Behavior in Mesoporous Templates

The physicochemical details of the well-established template-assisted electrodeposition process for metal nanowire fabrication are investigated with respect to the physical origination for template geometry limitation. The overall process of metal reduction inside anodized Al2 O3 (AAO) is divided into three parts: i) the electrochemical reduction at the pore bottom, ii) the diffusion of the electrolytic species, and iii) the capacitive interaction between pore surface and electrolyte. The results show that the reduction of Ni is controlled by the degree of electrode recession, i.e., the pore depth. Applying Cottrell's equation to pulsed electrodeposition enables experimental access to diffusion coefficients (DNi2+). This gives a gradient in DNi2+ along with the filling process. The switch-over from crystallization to diffusion control is investigated to depend on temperature and pore length. Additionally, the electrode surface capacitance scales non-linearly with the pore depth. This is deduced as a consequence of electrostatic surface-electrolyte interaction. A minimum in the electrode capacitance at a pore length of 48 μm is identified as the point with maximum thickness of a double-layer-type surface effect to the electrolyte. The results extend the template's role from simply geometrically limiting metal growth and explain occurring process issues when filling especially high-aspect-ratio pores.

Ultrasound-guided diagnosis of fractures of the distal forearm in children

PURPOSE

Distal radius and forearm fractures are injuries that are frequently seen in trauma surgery outpatient clinics. Usually, the wrist is X-rayed in 2 planes as standard diagnostic procedure. In contrast, we evaluate in our study the accuracy of ultrasonography (US) in diagnosing these fractures.

METHODS

This prospective study includes the patients who presented at two trauma surgery clinics with a presumptive diagnosis of distal radius or forearm fracture between January and December 2012. After a clinical examination, US imaging of the distal forearm was first carried out on 6 standardized planes followed by radiographs of the wrist made in two planes. The age limit was set at the end of 11 years.

RESULTS

In total, 201 patients between 4 and 11 years of age were recruited with an average age of 9.5 years at the time of the trauma. There were 104 (51.7%) fractures distributed as follows: 89 (85.9%) injuries of the distal radius, 9 (8.7%) injuries of the distal ulna, and 6 (5.8%) combined injuries (radius and ulna). Sixty-five greenstick fractures were detected. Surgery was necessary in 34 cases. Specificity and sensitivity of ultrasound diagnosis were 99.5%.

CONCLUSION

Ultrasound imaging is suitable to demonstrate fractures of the distal forearm. It is a highly sensitive procedure in detecting distal forearm fractures. In our opinion, a negative result in ultrasound may reduce the need for further radiographs in children with distal forearm lesions. But in any doubtful situation the need for conventional radiographs remains.

Electrochemical Reaction in Single Layer MoS2: Nanopores Opened Atom by Atom

Ultrathin nanopore membranes based on 2D materials have demonstrated ultimate resolution toward DNA sequencing. Among them, molybdenum disulfide (MoS2) shows long-term stability as well as superior sensitivity enabling high throughput performance. The traditional method of fabricating nanopores with nanometer precision is based on the use of focused electron beams in transmission electron microscope (TEM). This nanopore fabrication process is time-consuming, expensive, not scalable, and hard to control below 1 nm. Here, we exploited the electrochemical activity of MoS2 and developed a convenient and scalable method to controllably make nanopores in single-layer MoS2 with subnanometer precision using electrochemical reaction (ECR). The electrochemical reaction on the surface of single-layer MoS2 is initiated at the location of defects or single atom vacancy, followed by the successive removals of individual atoms or unit cells from single-layer MoS2 lattice and finally formation of a nanopore. Step-like features in the ionic current through the growing nanopore provide direct feedback on the nanopore size inferred from a widely used conductance vs pore size model. Furthermore, DNA translocations can be detected in situ when as-fabricated MoS2 nanopores are used. The atomic resolution and accessibility of this approach paves the way for mass production of nanopores in 2D membranes for potential solid-state nanopore sequencing.

Peripartum pubic symphysis separation--Current strategies in diagnosis and therapy and presentation of two cases

BACKGROUND

During spontaneous vaginal delivery, pubic symphyseal widening is normal. Common changes are reversible after complication-free birth. However, cases of peripartum symphysis separation are rare. There is no consensus in the literature on how to treat pregnancy-related pubic symphysis separation.

METHODS

This review used a literature-based search (PubMed, 1900-2013) and analysis of 2 own case reports. Studies with conclusions regarding management were particularly considered.

RESULTS

Characteristic symptoms, suprapubic pain and tenderness radiating to the posterior pelvic girdle or lower back, may be noted 48 h after delivery. Pain on movement, especially walking or climbing stairs, is often present. Conservative treatments, such as a pelvic brace with physiotherapy and local interventions such as infiltration, are successful in most cases. Symptom reduction within 6 weeks is the most common outcome, but can take up to 6 months in some cases. Surgical intervention is needed in cases of persistent separation. Anterior plate fixation is offered as a well-known and safe procedure. Minimally invasive SI joint screw fixation is required in cases of combined posterior pelvic girdle lesions.

SUMMARY

Postpartum symphyseal rupture can be indicated with the rare occurrence of pelvic pain post-delivery, with sciatica or lumbago and decreased mobility. The diagnosis is made on clinical findings, as well as radiographs of the pelvic girdle. Conservative treatment with a pelvic brace is the gold standard in pre- and postpartum cases of symphysis dysfunction.

Injuries and overuse syndromes in competitive and elite bodybuilding

Competitive bodybuilding is a weightlifting sport similar to powerlifting, strongman competition and Olympic weightlifting, which aims to increase muscle mass, symmetry, and body definition. Although data regarding rates of injury, overuse syndromes and pain during routine training is available for these other disciplines, it is rare for competitive bodybuilding. The aim of this study was to investigate rates of injury, pain during workouts and/or overuse syndromes, as well as the influence of particular intrinsic and external factors. Data was collected using questionnaires from 71 competitive and elite bodybuilders. The information included training routines and prior injuries. Participants were recruited from bodybuilding clubs in Germany. 45.1% of athletes reported symptoms while training. The overall injury rate was computed to be 0.12 injuries per bodybuilder per year (0.24 injuries per 1 000 h of bodybuilding). Athletes over 40 exhibited higher rates of injury (p=0.029). Other investigated parameters showed no effects. Most injuries occurred in the shoulder, elbow, lumbar spine and knee regions. A large proportion of bodybuilders complained of pain not resulting in interruptions of training/competition. The injury rate is low compared to other weightlifting disciplines such as powerlifting, Olympic weightlifting or strongman competition. In comparison to team or contact sports the injury rate is minimal.

Exchangeable colloidal AFM probes for the quantification of irreversible and long-term interactions

An original method is presented to study single-colloid interaction with a substrate in liquid environment. Colloids, either in solution or adsorbed on a surface, are fixed by suction against the aperture of a microchanneled atomic force microscopy cantilever. Their adhesion to the substrate is measured, followed by their release via a short overpressure surge. Such colloid exchange procedure allows for 1), the quick variation of differently functionalized colloids within the same experiment; 2), the investigation of long-term interactions by leaving the colloids on a surface for a defined time before detaching them; and 3), the inspection of irreversible interactions. After validation of the method by reproducing literature results obtained with traditional colloidal atomic force microscopy, the serial use of colloids with different surface functionalization was shown on a micropatterned surface. Finally, concanavalin A-coated colloids were allowed to adsorb on human embryonic kidney cells and then detached one by one. The adhesion between cells and colloids was up to 60 nN, whereas individual cells adhered with 20 nN to the glass substrate. A cellular elastic modulus of 0.8 kPa was determined using the attached colloid as indenter.

Detection of RNAP-DNA complexes using solid state nanopores

Transcription is the first step in gene expression where DNA is copied into RNA. It is extensively studied at the bulk level especially the regulation mechanism, which in cancerous cells is impaired. We were interested in studying E. coli RNAP enzyme at the single-molecule level for its functional as well as molecular motor properties. With nanopore sensing, we were able to observe RNA polymerase-DNA complexes translocate through nanopores and able to distinguish between individual complexes and bare RNA polymerase. We were also able to observe orientation of RNA polymerase in the nanopore whether flow or electric field predominates. The complexity of the signals from the protein-DNA complexes experiment motivated us to develop level detection software. This software is based on a change detection method called the CUSUM algorithm. OpenNanpore software was designed to analyze in details current blockages in nanopore signals with very little prior knowledge on the signal. With this work one can separate events according to their number of levels and study those sub-populations separately.

Fast and automatic processing of multi-level events in nanopore translocation experiments

We have developed a method to analyze in detail, translocation events providing a novel and flexible tool for data analysis of nanopore experiments. Our program, called OpenNanopore, is based on the cumulative sums algorithm (CUSUM algorithm). This algorithm is an abrupt change detection algorithm that provides fitting of current blockages, allowing the user to easily identify the different levels in each event. Our method detects events using adaptive thresholds that adapt to low-frequency variations in the baseline. After event identification, our method uses the CUSUM algorithm to fit the levels inside every event and automatically extracts their time and amplitude information. This facilitates the statistical analysis of an event population with a given number of levels. The obtained information improves the interpretation of interactions between the molecule and nanopore. Since our program does not require any prior information about the analyzed molecules, novel molecule-nanopore interactions can be characterized. In addition our program is very fast and stable. With the progress in fabrication and control of the translocation speed, in the near future, our program could be useful in identification of the different bases of DNA.

[Operative treatment of pediatric open fractures of the lower limb using the Taylor spatial frame fixator]

The operative management of open fractures of the lower limb requires a consistent treatment to avoid soft tissue complications. Acute angular shortening of the fracture enabling primary soft tissue closure is still an uncommon operative technique because of difficulties in correcting the secondary deformity. The case of a pediatric open fracture of the lower limb (Gustilo type IIIa) is described, which was treated with acute angular shortening followed by gradual correction using the Taylor spatial frame (TSF).