Vascular study of decellularized porcine long bones: Characterization of a tissue engineering model

INTRODUCTION

Massive bone allografts enable the reconstruction of critical bone defects in numerous conditions (e.g. tumoral, infection or trauma). Unfortunately, their biological integration remains insufficient and the reconstruction may suffer from several postoperative complications. Perfusion-decellularization emerges as a tissue engineering potential solution to enhance osseointegration. Therefore, an intrinsic vascular study of this novel tissue engineering tool becomes essential to understand its efficacy and applicability.

MATERIAL AND METHODS

32 porcine long bones (humeri and femurs) were used to assess the quality of their vascular network prior and after undergoing a perfusion-decellularization protocol. 12 paired bones were used to assess the vascular matrix prior (N = 6) and after our protocol (N = 6) by immunohistochemistry. Collagen IV, Von Willebrand factor and CD31 were targeted then quantified. The medullary macroscopic vascular network was evaluated with 12 bones: 6 were decellularized and the other 6 were, as control, not treated. All 12 underwent a contrast-agent injection through the nutrient artery prior an angio CT-scan acquisition. The images were processed and the length of medullary vessels filled with contrast agent were measured on angiographic cT images obtained in control and decellularized bones by 4 independent observers to evaluate the vascular network preservation. The microscopic cortical vascular network was evaluated on 8 bones: 4 control and 4 decellularized. After injection of gelatinous fluorochrome mixture (calcein green), non-decalcified fluoroscopic microscopy was performed in order to assess the perfusion quality of cortical vascular lacunae.

RESULTS

The continuity of the microscopic vascular network was assessed with Collagen IV immunohistochemistry (p-value = 0.805) while the decellularization quality was observed through CD31 and Von Willebrand factor immunohistochemistry (p-values <0.001). The macroscopic vascular network was severely impaired after perfusion-decellularization; nutrient arteries were still patent but the amount of medullary vascular channels measured was significantly higher in the control group compared to the decellularized group (p-value <0.001). On average, the observers show good agreement on these results, except in the decellularized group where more inter-observer discrepancies were observed. The microscopic vascular network was observed with green fluoroscopic signal in almost every canals and lacunae of the bone cortices, in three different bone locations (proximal metaphysis, diaphysis and distal metaphysis).

CONCLUSION

Despite the aggressiveness of the decellularization protocol on medullary vessels, total porcine long bones decellularized by perfusion retain an acellular cortical microvascular network. By injection through the intact nutrient arteries, this latter vascular network can still be used as a total bone infusion access for bone tissue engineering in order to enhance massive bone allografts prior implantation.

ARNI effects in HFrEF. Risk reduction beyond LVEF

Background

The imbalance of cardiac autonomic nervous system function plays an important role in heart failure associated mortality. ARNI has demonstrated a paramount effect in reducing risk of death and hospitalization for worsening of heart failure. However, its exact mechanism of action remains only partly understood. We sought to prospectively compare heart rate variability as a noninvasive measure of cardiac autonomic nervous system function.

Methods

The study design was prospective sequential observational. Patients served as their own internal control. Patients with heart failure with reduced ejection fraction (HFrEF) receiving optimal medical therapy who were scheduled for a switch to ARNI therapy underwent echocardiography and a standardized 30-minute 12-lead Holter ECG recording before starting ARNI therapy. A monitoring of the parameters was performed 3 months after the start of therapy. Physicians were instructed to increase ARNI dose to the highest tolerated or maximum dose. Besides left ventricular ejection fraction (LVEF) we assessed heart rate (HR), standard deviation of normal-to-normal intervals (SDNN) and mean square of differences between consecutive R-R intervals (RMSSD).

Results

We recruited 55 patients and baseline characteristics were as follows: age 65±12 years, male sex 78%, NT-proBNP 4989±809 pg/ml, LVEF 28±6%, HR 75±9 bpm, SDNN 43±2 ms, RMSSD 19±2 ms. All patients received beta-blocker therapy and the dosage was similar at baseline and follow-up. After 3 months of ARNI therapy, heart rate showed a significant reduction of 7% (74±14 bpm vs. 69±11 min, P=0.005). SDNN increased by 49% (43±2 ms vs. 64±4 ms, P&lt;0.001) and RMSSD by 42% (19±2 ms vs. 27±3 ms, P=0.01). These results were accompanied by increased LVEF (28±6% vs. 38±10%, P&lt;0.001) and reduced plasma NT-proBNP levels (4989±809 pg/ml vs. 2602±87 pg/ml, P&lt;0.04). NYHA Class of affected patients changed from III to II.

Conclusion

After changing from ACE/AT1-I to ARNI, significant improvement of autonomic cardiac nervous system function could be observed. ARNI apparently activates the parasympathetic nervous system as suggested by decreased HR and increased SDNN and RMSSD. Therefore, part of its cardioprotective and beneficial effects may relate to the restoration of autonomic cardiac nervous system function. Potential beneficial effects regarding incidence of sudden cardiac arrest may relate to these observations.

Funding Acknowledgement

Type of funding sources: None.

An Ultra-Fast TSP on a CNT Heating Layer for Unsteady Temperature and Heat Flux Measurements in Subsonic Flows

In this paper, the authors demonstrate the application of a modified Ru(phen)-based temperature-sensitive paint which was originally developed for the evaluation of unsteady aero-thermodynamic phenomena in high Mach number but short duration experiments. In the present work, the modified TSP with a temperature sensitivity of up to -5.6%/K was applied in a low Mach number long-duration test case in a low-pressure environment. For the demonstration of the paint's performance, a flat plate with a mounted cylinder was set up in the High-Speed Cascade Wind Tunnel (HGK). The test case was designed to generate vortex shedding frequencies up to 4300 Hz which were sampled using a high-speed camera at 40 kHz frame rate to resolve unsteady surface temperature fields for potential heat-transfer estimations. The experiments were carried out at reduced ambient pressure of p∞ = 13.8 kPa for three inflow Mach numbers being Ma∞=[0.3;0.5;0.7]. In order to enable the resolution of very low temperature fluctuations down to the noise floor of 10-5 K with high spatial and temporal resolution, the flat plate model was equipped with a sprayable carbon nanotube (CNT) heating layer. This constellation, together with the thermal sensors incorporated in the model, allowed for the calculation of a quasi-heat-transfer coefficient from the surface temperature fields. Besides the results of the experiments, the paper highlights the properties of the modified TSP as well as the methodology.

Complication rates of percutaneous brachial artery puncture: effect of live ultrasound guidance

Purpose

The current literature on the use of brachial artery access is controversial. Some studies found increased puncture site complications. Others found no higher complication rates than in patients with femoral or radial access. The purpose of this study was to determine the impact of ultrasound (US)-guidance on access site complications.

Materials and methods

This is a single-center retrospective study of all consecutive patients with brachial arterial access for interventional procedures. Complications were classified into minor complications (conservative treatment only) and major complications (requiring surgical intervention). The brachial artery was cannulated in the antecubital fossa under US-guidance. After the intervention, manual compression or closure devices, both followed by a compression bandage for 3 h, either achieved hemostasis.

Results

Seventy-five procedures in seventy-one patients were performed in the study period using brachial access. Access was successful in all cases (100%). Procedures in different vascular territories were performed: neurovascular (10/13.5%), upper extremity (32/43.2%), visceral (20/27.0%), and lower extremity (12/16.3%). Sheath size ranged from 3.2F to 8F (mean: 5F). Closure devices were used in 17 cases (22.7%). In total, six complications were observed (8.0%), four minor complications (5.3%, mostly puncture site hematomas), and two major complications, that needed surgical treatment (2.7%). No brachial artery thrombosis or upper extremity ischemia occurred.

Conclusion

Exclusive use of US-guidance resulted in a low risk of brachial artery access site complications in our study compared to the literature. US-guidance has been proven to reduce the risk of access site complications in several studies in femoral access. In addition, brachial artery access yields a high technical success rate and requires no additional injection of spasmolytic medication. Sheath size was the single significant predictor for complications.

Treatment resistance analysis reveals GLUT-1-mediated glucose uptake as a major target of synthetic rocaglates in cancer cells

Rocaglates are natural compounds that have been extensively studied for their ability to inhibit translation initiation. Rocaglates represent promising drug candidates for tumor treatment due to their growth‐inhibitory effects on neoplastic cells. In contrast to natural rocaglates, synthetic analogues of rocaglates have been less comprehensively characterized, but were also shown to have similar effects on the process of protein translation. Here, we demonstrate an enhanced growth‐inhibitory effect of synthetic rocaglates when combined with glucose anti‐metabolite 2‐deoxy‐D‐glucose (2DG) in different cancer cell lines. Moreover, we unravel a new aspect in the mechanism of action of synthetic rocaglates involving reduction of glucose uptake mediated by downregulation or abrogation of glucose transporter GLUT‐1 expression. Importantly, cells with genetically induced resistance to synthetic rocaglates showed substantially less pronounced treatment effect on glucose metabolism and did not demonstrate GLUT‐1 downregulation, pointing at the crucial role of this mechanism for the anti‐tumor activity of the synthetic rocaglates. Transcriptome profiling revealed glycolysis as one of the major pathways differentially regulated in sensitive and resistant cells. Analysis of synthetic rocaglate efficacy in a 3D tissue context with a co‐culture of tumor and normal cells demonstrated a selective effect on tumor cells and substantiated the mechanistic observations obtained in cancer cell lines. Increased glucose uptake and metabolism is a universal feature across different tumor types. Therefore, targeting this feature by synthetic rocaglates could represent a promising direction for exploitation of rocaglates in novel anti‐tumor therapies.

Phase separation directs ubiquitination of gene-body nucleosomes

The conserved yeast E3 ubiquitin ligase Bre1 and its partner, the E2 ubiquitin-conjugating enzyme Rad6, monoubiquitinate histone H2B across gene bodies during the transcription cycle¹. Although processive ubiquitination might-in principle-arise from Bre1 and Rad6 travelling with RNA polymerase II², the mechanism of H2B ubiquitination across genic nucleosomes remains unclear. Here we implicate liquid-liquid phase separation³ as the underlying mechanism. Biochemical reconstitution shows that Bre1 binds the scaffold protein Lge1, which possesses an intrinsically disordered region that phase-separates via multivalent interactions. The resulting condensates comprise a core of Lge1 encapsulated by an outer catalytic shell of Bre1. This layered liquid recruits Rad6 and the nucleosomal substrate, which accelerates the ubiquitination of H2B. In vivo, the condensate-forming region of Lge1 is required to ubiquitinate H2B in gene bodies beyond the +1 nucleosome. Our data suggest that layered condensates of histone-modifying enzymes generate chromatin-associated 'reaction chambers', with augmented catalytic activity along gene bodies. Equivalent processes may occur in human cells, and cause neurological disease when impaired.

Quantification of Blood Velocity with 4D Digital Subtraction Angiography Using the Shifted Least-Squares Method

BACKGROUND AND PURPOSE

4D-DSA provides time-resolved 3D-DSA volumes with high temporal and spatial resolutions. The purpose of this study is to investigate a shifted least squares method to estimate the blood velocity from the 4D DSA images. Quantitative validation was performed using a flow phantom with an ultrasonic flow probe as ground truth. Quantification of blood velocity in human internal carotid arteries was compared with measurements generated from 3D phase-contrast MR imaging.

MATERIALS AND METHODS

The centerlines of selected vascular segments and the time concentration curves of each voxel along the centerlines were determined from the 4D-DSA dataset. The temporal shift required to achieve a minimum difference between any point and other points along the centerline of a segment was calculated. The temporal shift as a function of centerline point position was fit to a straight line to generate the velocity. The proposed shifted least-squares method was first validated using a flow phantom study. Blood velocities were also estimated in the 14 ICAs of human subjects who had both 4D-DSA and phase-contrast MR imaging studies. Linear regression and correlation analysis were performed on both the phantom study and clinical study, respectively.

RESULTS

Mean velocities of the flow phantom calculated from 4D-DSA matched very well with ultrasonic flow probe measurements with 11% relative root mean square error. Mean blood velocities of ICAs calculated from 4D-DSA correlated well with phase-contrast MR imaging measurements with Pearson correlation coefficient r = 0.835.

CONCLUSIONS

The availability of 4D-DSA provides the opportunity to use the shifted least-squares method to estimate velocity in vessels within a 3D volume.

Recursive decentralized localization for multi-robot systems with asynchronous pairwise communication

This paper provides a fully decentralized algorithm for collaborative localization based on the extended Kalman filter. The major challenge in decentralized collaborative localization is to track inter-robot dependencies, which is particularly difficult when sustained synchronous communication between the robots cannot be guaranteed. Current approaches suffer from the need for particular communication schemes, extensive bookkeeping of measurements, overly conservative assumptions, or the restriction to specific measurement models. This paper introduces a localization algorithm that is able to approximate the inter-robot correlations while fulfilling all of the following conditions: communication is limited to two robots that obtain a relative measurement, the algorithm is recursive in the sense that it does not require storage of measurements and each robot maintains only the latest estimate of its own pose, and it supports generic measurement models. The fact that the proposed approach can handle these particularly difficult conditions ensures that it is applicable to a wide range of multi-robot scenarios. We provide mathematical details on our approximation. Extensive experiments carried out using real-world datasets demonstrate the improved performance of our method compared with several existing approaches.

Correlations between Motor Symptoms across Different Motor Tasks, Quantified via Random Forest Feature Classification in Parkinson's Disease

Background

Objective assessments of Parkinson’s disease (PD) patients’ motor state using motion capture techniques are still rarely used in clinical practice, even though they may improve clinical management. One major obstacle relates to the large dimensionality of motor abnormalities in PD. We aimed to extract global motor performance measures covering different everyday motor tasks, as a function of a clinical intervention, i.e., deep brain stimulation (DBS) of the subthalamic nucleus.

Methods

We followed a data-driven, machine-learning approach and propose performance measures that employ Random Forests with probability distributions. We applied this method to 14 PD patients with DBS switched-off or -on, and 26 healthy control subjects performing the Timed Up and Go Test (TUG), the Functional Reach Test (FRT), a hand coordination task, walking 10-m straight, and a 90° curve.

Results

For each motor task, a Random Forest identified a specific set of metrics that optimally separated PD off DBS from healthy subjects. We noted the highest accuracy (94.6%) for standing up. This corresponded to a sensitivity of 91.5% to detect a PD patient off DBS, and a specificity of 97.2% representing the rate of correctly identified healthy subjects. We then calculated performance measures based on these sets of metrics and applied those results to characterize symptom severity in different motor tasks. Task-specific symptom severity measures correlated significantly with each other and with the Unified Parkinson’s Disease Rating Scale (UPDRS, part III, correlation of r² = 0.79). Agreement rates between different measures ranged from 79.8 to 89.3%.

Conclusion

The close correlation of PD patients’ various motor abnormalities quantified by different, task-specific severity measures suggests that these abnormalities are only facets of the underlying one-dimensional severity of motor deficits. The identification and characterization of this underlying motor deficit may help to optimize therapeutic interventions, e.g., to “automatically” adapt DBS settings in PD patients.

Improvement of mesh recolonization in abdominal wall reconstruction with adipose vs. bone marrow mesenchymal stem cells in a rodent model

BACKGROUND

Reconstruction of muscle defects remains a challenge. Our work assessed the potential of an engineered construct made of a human acellular collagen matrix (HACM) seeded with porcine mesenchymal stem cells (MSCs) to reconstruct abdominal wall muscle defects in a rodent model.

METHODS

This study compared 2 sources of MSCs (bone-marrow, BMSCs, and adipose, ASCs) in vitro and in vivo for parietal defect reconstruction. Cellular viability and growth factor release (VEGF, FGF-Beta, HGF, IGF-1, TGF-Beta) were investigated under normoxic/hypoxic culture conditions. Processed and recellularized HACMs were mechanically assessed. The construct was tested in vivo in full thickness abdominal wall defect treated with HACM alone vs. HACM+ASCs or BMSCs (n=14). Tissue remodeling was studied at day 30 for neo-angiogenesis and muscular reconstruction.

RESULTS

A significantly lower secretion of IGF was observed with ASCs vs. BMSCs under hypoxic conditions (-97.6%, p<0.005) whereas significantly higher VEGF/FGF secretions were found with ASCs (+92%, p<0.001 and +72%, p<0.05, respectively). Processing and recellularization did not impair the mechanical properties of the HACM. In vivo, angiogenesis and muscle healing were significantly improved by the HACM+ASCs in comparison to BMSCs (p<0.05) at day 30.

CONCLUSION

A composite graft made of an HACM seeded with ASCs can improve muscle repair by specific growth factor release in hypoxic conditions and by in vivo remodeling (neo-angiogenesis/graft integration) while maintaining mechanical properties.

Comparison of the Diagnostic Utility of 4D-DSA with Conventional 2D- and 3D-DSA in the Diagnosis of Cerebrovascular Abnormalities

BACKGROUND AND PURPOSE

4D-DSA is a time-resolved technique that allows viewing of a contrast bolus at any time and from any desired viewing angle. Our hypothesis was that the information content in a 4D-DSA reconstruction was essentially equivalent to that in a combination of 2D acquisitions and a 3D-DSA reconstruction.

MATERIALS AND METHODS

Twenty-six consecutive patients who had both 2D- and 3D-DSA acquisitions were included in the study. The angiography report was used to obtain diagnoses and characteristics of abnormalities. Diagnoses included AVM/AVFs, aneurysms, stenosis, and healthy individuals. 4D-DSA reconstructions were independently reviewed by 3 experienced observers who had no part in the clinical care. Using an electronic evaluation form, these observers recorded their assessments based only on the 4D reconstructions. The clinical evaluations were then compared with the 4D evaluations for diagnosis and lesion characteristics.

RESULTS

Results showed both interrater and interclass agreements (κ = 0.813 and 0.858). Comparing the 4D diagnosis with the clinical diagnosis for the 3 observers yielded κ values of 0.906, 0.912, and 0.906. The κ values for agreement among the 3 observers for the type of abnormality were 0.949, 0.845, and 0.895. There was complete agreement on the presence of an abnormality between the clinical and 4D-DSA in 23/26 cases. In 2 cases, there were conflicting opinions.

CONCLUSIONS

In this study, the information content of 4D-DSA reconstructions was largely equivalent to that of the combined 2D/3D studies. The availability of 4D-DSA should reduce the requirement for 2D-DSA acquisitions.

Enhanced vascular biocompatibility of decellularized xeno-/allogeneic matrices in a rodent model

Glutaraldehyde preservation is the gold standard for cardiovascular biological prosthesis. However, secondary calcifications and the absence of tissue growth remain major limitations. Our study assessed in vitro and in vivo the biocompatibility of human (fascia lata, pericardium) and porcine tissues (pericardium, peritoneum) treated with a physicochemical procedure for decellularization and non-conventional pathogens inactivation. Biopsies were performed before and after treatment to assess decellularization (HE/Dapi staining/DNA quantification/MHC I/alpha gal immunostaining) and mechanical integrity. Forty-five rats received an abdominal aortic patch of native cryopreserved tissues (n = 20), treated tissues (n = 20) or glutaraldehyde-preserved bovine pericardium (GBP, control, n = 5). Grafts were explanted at 4 weeks and processed for HE/von Kossa staining and immunohistochemistries for lymphocytes (CD3)/macrophages (CD68) histomorphometry. 95% of decellularization was obtained for all tissues except for fascia lata (75%). Mechanical properties were slightly altered. In the in vivo model, a significant increase of CD3 and CD68 infiltrations was found in native and control implants in comparison with decellularized tissues (p < 0.05). Calcifications were found in 3 controls. Decellularized tissues were recolonized. GBP showed the most inflammatory response. This physicochemical treatment improves the biocompatibility of selected xeno/allogeneic tissues in comparison with their respective native cryopreserved tissues and with GBP. Incomplete decellularization is associated with a significantly higher inflammatory response. Our treatment is a promising tool in the field of tissue decellularization and tissue banking.

PHF13 is a molecular reader and transcriptional co-regulator of H3K4me2/3

PHF13 is a chromatin affiliated protein with a functional role in differentiation, cell division, DNA damage response and higher chromatin order. To gain insight into PHF13's ability to modulate these processes, we elucidate the mechanisms targeting PHF13 to chromatin, its genome wide localization and its molecular chromatin context. Size exclusion chromatography, mass spectrometry, X-ray crystallography and ChIP sequencing demonstrate that PHF13 binds chromatin in a multivalent fashion via direct interactions with H3K4me2/3 and DNA, and indirectly via interactions with PRC2 and RNA PolII. Furthermore, PHF13 depletion disrupted the interactions between PRC2, RNA PolII S5P, H3K4me3 and H3K27me3 and resulted in the up and down regulation of genes functionally enriched in transcriptional regulation, DNA binding, cell cycle, differentiation and chromatin organization. Together our findings argue that PHF13 is an H3K4me2/3 molecular reader and transcriptional co-regulator, affording it the ability to impact different chromatin processes.

DOI:http://dx.doi.org/10.7554/eLife.10607.001

In human and other eukaryotic cells, DNA is packaged around proteins called histones to form a structure known as chromatin. Chemical tags added to the histones alter how the DNA is packaged and the activity of the genes encoded by that DNA. For example, many active genes are packaged around histone H3 proteins that have “Lysine 4 tri-methyl” tags attached to them. Another protein that is associated with chromatin is called PHF13 and it has several roles, including repairing damaged DNA. However, it was not known whether PHF13 binds to chromatin via the chemical tags, or in another way.

Ho-Ryun, Xu, Fuchs et al. used several biochemical techniques in mouse and human cells to explore how PHF13 specifically interacts with chromatin. These experiments showed that PHF13 binds specifically to DNA and to two types of methyl tags (lysine 4-tri-methyl or lysine 4-di-methyl). These chemical tags are predominantly found at active promoters as well as at a small subset of less active promoters known as bivalent promoters. PHF13 interacted with other proteins on the chromatin that are known to either drive or repress gene activity and it’s depletion affected the activity of many genes. Whether PHF13 increased or decreased gene activity depended on whether it was bound to active or bivalent promoters. The active promoters targeted by PHF13 had higher numbers of the tri-methyl tags whereas the di-methyl tags were more common on the bivalent promoters.

These findings provide preliminary evidence that a protein binding to different methyl tags in the same place on histone H3 can have opposite effects on gene activity. Ho-Ryun, Xu, Fuchs et al. now intend to find out more about the other proteins that interact with PHF13 on chromatin.

DOI:http://dx.doi.org/10.7554/eLife.10607.002

Mediator and TREX-2: Emerging links between transcription initiation and mRNA export

Nuclear pore proteins interact dynamically with chromatin to regulate gene activities. A key question is how nucleoporin interactions mechanistically alter a gene's intranuclear position and transcriptional output. We reported recently on a direct interaction between the nuclear pore-associated TREX-2 complex and promoter-bound Mediator. This highlights how nuclear-pore associated adaptors gain regulatory access to the core transcription machinery. In this Extra View, we discuss an additional implication that arises from our work and the recent literature: how promoter elements may regulate mRNA metabolism beyond transcription initiation.

Controlled synthesis of PVP-based carbon-supported Ru nanoparticles: synthesis approaches, characterization, capping agent removal and catalytic behavior

PVP-capped Ru nanoparticles were synthesized, immobilized on several carbon supports and tested in galactose hydrogenation.

The Nuclear Pore-Associated TREX-2 Complex Employs Mediator to Regulate Gene Expression

Nuclear pore complexes (NPCs) influence gene expression besides their established function in nuclear transport. The TREX-2 complex localizes to the NPC basket and affects gene-NPC interactions, transcription, and mRNA export. How TREX-2 regulates the gene expression machinery is unknown. Here, we show that TREX-2 interacts with the Mediator complex, an essential regulator of RNA Polymerase (Pol) II. Structural and biochemical studies identify a conserved region on TREX-2, which directly binds the Mediator Med31/Med7N submodule. TREX-2 regulates assembly of Mediator with the Cdk8 kinase and is required for recruitment and site-specific phosphorylation of Pol II. Transcriptome and phenotypic profiling confirm that TREX-2 and Med31 are functionally interdependent at specific genes. TREX-2 additionally uses its Mediator-interacting surface to regulate mRNA export suggesting a mechanism for coupling transcription initiation and early steps of mRNA processing. Our data provide mechanistic insight into how an NPC-associated adaptor complex accesses the core transcription machinery.

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The nuclear pore-associated TREX-2 complex directly interacts with Mediator

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TREX-2 regulates Mediator association with Cdk8 and RNA Pol II Ser5 phosphorylation

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TREX-2 and the Med31 submodule co-regulate specific inducible and constitutive genes

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A similar TREX-2 surface promotes both transcription and mRNA export

Impact of perioperative chemotherapy on survival in patients with advanced primary urethral cancer: results of the international collaboration on primary urethral carcinoma

BACKGROUND

To investigate the impact of perioperative chemo(radio)therapy in advanced primary urethral carcinoma (PUC).

PATIENTS AND METHODS

A series of 124 patients (86 men, 38 women) were diagnosed with and underwent surgery for PUC in 10 referral centers between 1993 and 2012. Kaplan-Meier analysis with log-rank testing was used to investigate the impact of perioperative chemo(radio)therapy on overall survival (OS). The median follow-up was 21 months (mean: 32 months; interquartile range: 5-48).

RESULTS

Neoadjuvant chemotherapy (NAC), neoadjuvant chemoradiotherapy (N-CRT) plus adjuvant chemotherapy (ACH), and ACH was delivered in 12 (31%), 6 (15%) and 21 (54%) of these patients, respectively. Receipt of NAC/N-CRT was associated with clinically node-positive disease (cN+; P = 0.033) and lower utilization of cystectomy at surgery (P = 0.015). The objective response rate to NAC and N-CRT was 25% and 33%, respectively. The 3-year OS for patients with objective response to neoadjuvant treatment (complete/partial response) was 100% and 58.3% for those with stable or progressive disease (P = 0.30). Of the 26 patients staged ≥cT3 and/or cN+ disease, 16 (62%) received perioperative chemo(radio)therapy and 10 upfront surgery without perioperative chemotherapy (38%). The 3-year OS for this locally advanced subset of patients (≥cT3 and/or cN+) who received NAC (N = 5), N-CRT (N = 3), surgery-only (N = 10) and surgery plus ACH (N = 8) was 100%, 100%, 50% and 20%, respectively (P = 0.016). Among these 26 patients, receipt of neoadjuvant treatment was significantly associated with improved 3-year relapse-free survival (RFS) (P = 0.022) and OS (P = 0.022). Proximal tumor location correlated with inferior 3-year RFS and OS (P = 0.056/0.005).

CONCLUSION

In this series, patients who received NAC/N-CRT for cT3 and/or cN+ PUC appeared to demonstrate improved survival compared with those who underwent upfront surgery with or without ACH.

Attenuation of blood flow pulsatility along the Atlas slope: a physiologic property of the distal vertebral artery?

BACKGROUND AND PURPOSE

Physiologic and pathologic arterial tortuosity may attenuate blood flow pulsatility. The aim of this prospective study was to assess a potential effect of the curved V3 segment (Atlas slope) of the vertebral artery on arterial flow pulsatility. The pulsatility index and resistance index were used to assess blood flow pulsatility.

MATERIALS AND METHODS

Twenty-one healthy volunteers (17 men, 4 women; mean age, 32 years) were examined with a 3T MR imaging system. Blood velocities were measured at 2 locations below (I and II) and at 1 location above the V3 segment (III) of the vertebral artery by using a high-resolution 2D-phase-contrast sequence with multidirectional velocity-encoding.

RESULTS

Pulsatility and resistance indices decreased along all measurement locations from proximal to distal. The pulsatility index decreased significantly from location II to III and from I to II. However, the decrease was more pronounced along the Atlas slope than in the straight-vessel section below. The decrease of the resistance index was highly significant along the Atlas slope (location II to III). The decrease from location I to II was small and not significant.

CONCLUSIONS

The pronounced decrease in pulsatility and resistance indices along the interindividually uniformly bent V3 segment compared with a straight segment of the vertebral artery indicates a physiologic attenuating effect of the Atlas slope on arterial flow pulsatility. A similar effect has been described for the carotid siphon. A physiologic reduction of pulsatility in brain-supplying arteries would be in accordance with several recent publications reporting a correlation of increased arterial flow pulsatility with leukoencephalopathy and lacunar stroke.

First Report of Rose rosette virus Associated with Rose Rosette Disease Infecting Knockout Roses in Florida

Roses are one of the most popular flowering shrubs in the United States, with a total wholesale value of US$194 million. Among the major states, Florida is the fourth largest producer of roses with a total value exceeding US$20 million (4). In Florida, the roses have become especially popular in recent years with the introduction of Knock Out and other shrub roses. Virus-like symptoms including witches'-broom, excessive thorns, abnormal red discoloration of shoots and foliages, distorted leaves, and deformed buds and flowers were initially observed on Knock Out roses in a commercial nursery in Quincy, FL, in November 2013. Fifteen plants out of ~250,000 plants showed these characteristic symptoms. Total RNA extracts (RNeasy Plant Mini Kit, Qiagen, Valencia, CA) from eight symptomatic and two non-symptomatic rose samples were subjected to reverse-transcription (RT) assays using SuperScript III Reverse transcriptase (Invitrogen, Life Technologies, NY) and random hexamer primers. The cDNA synthesized was then subjected to PCR assay using Platinum Taq DNA polymerase (Invitrogen, Life Technologies) and using Rose rosette virus (RRV) specific primers RRV-F and RRV-R (1), targeting the core region of the RNA1 genome of the virus. The RT-PCR assays using the specific primers produced amplicons of 375 bp, only in the symptomatic leaf samples. The obtained amplicons were PCR purified and sequenced directly (GenBank Accession Nos. KF990370 to KF990377). BLAST analysis of these sequences revealed a higher identity of 99% with the RRV (HQ871942) in the NCBI database. Pairwise comparison of the eight RRV sequences exhibited 99 to 100% identity among themselves. These results revealed the association of RRV with the symptomatic rose plants. Eight symptomatic and two non-symptomatic rose plant samples were tested for RRV using blot hybridization assay, utilizing a digoxigenin-labeled DNA probe of 511 bp, targeting the RNA1 genome of the RRV. All eight symptomatic rose plants showed a positive reaction to the RRV-specific probes, confirming the presence of RRV in the samples, while the non-symptomatic and the buffer control did not produce any reactions. Even though the virus is reported to spread by an eriophyid mite Phyllocoptes fructiphilus, thorough examination of the infected samples showed absence of the vector. The samples were also tested using RT-PCR for the presence of Rose cryptic virus (RCV) and Blackberry chlorotic ringspot virus (BCRV) using specific primers (2,3). The samples tested negative for the RCV and BCRV. This is the first report of occurrence of RRV on rose in Florida. Considering the economic importance of the rose plants and the highly destructive nature of RRV, this report underscores the need for immediate effective quarantine and management of the virus for protecting the economically important rose industry in Florida. References: (1) A. G. Laney et al. J. Gen. Virol. 92:1727, 2011. (2) S. Sabanadzovic and N. Abou Ghanem-Sabanadzovic. J. Plant Pathol. 90:287, 2008. (3) I. E. Tzanetakis et al. Plant Pathol. 55:568, 2006. (4) USDA. 2007 Census of Agriculture 3:25, Washington, DC, 2010.

Expectation mismatch: differences between self-generated and cue-induced expectations

Expectation of upcoming stimuli and tasks can lead to improved performance, if the anticipated situation occurs, while expectation mismatch can lead to less efficient processing. Researchers have used methodological approaches that rely on either self-generated expectations (predictions) or cue-induced expectations to investigate expectation mismatch effects. Differentiating these two types of expectations for different contents of expectation such as stimuli, responses, task sets and conflict level, we review evidence suggesting that self-generated expectations lead to larger facilitating effects and conflict effects on the behavioral and neural level - as compared to cue-based expectations. On a methodological level, we suggest that self-generated as compared to cue-induced expectations allow for a higher amount of experimental control in many experimental designs on expectation effects. On a theoretical level, we argue for qualitative differences in how cues vs. self-generated expectations influence performance. While self-generated expectations might generally involve representing the expected event in the focus of attention in working memory, cues might only lead to such representations under supportive circumstances (i.e., cue of high validity and attended).

Levetiracetam rectal administration in healthy dogs

BACKGROUND

Levetiracetam is used to manage status epilepticus (SE) and cluster seizures (CS) in humans. The drug might be absorbed after rectal administration and could offer a practical adjunct to rectal administration of diazepam in managing SE and CS.

HYPOTHESIS

Levetiracetam is rapidly absorbed after rectal administration in dogs and maintains target serum concentrations for at least 9 hours.

ANIMALS

Six healthy privately owned dogs between 2 and 6 years of age and weighing 10-20 kg.

METHODS

Levetiracetam (40 mg/kg) was administered rectally and blood samples were obtained immediately before (time zero) and at 10, 20, 40, 60, 90, 180, 360, and 540 minutes after drug administration. Dogs were observed for signs of adverse effects over a 24-hour period after drug administration.

RESULTS

CLEV at 10 minutes was 15.3 ± 5.5 μg/mL (mean, SD) with concentrations in the target range (5-40 μg/mL) for all dogs throughout the sampling period. Cmax (36.0 ± 10.7 μg/mL) and Tmax (103 ± 31 minutes) values were calculated and 2 disparate groups were appreciated. Dogs with feces in the rectum at the time of drug administration had lower mean Cmax values (26.7 ± 3.4 μg/mL) compared with those without (45.2 ± 4.4 μg/mL). Mild sedation was observed between 60 and 90 minutes without other adverse effects noted.

CONCLUSIONS AND CLINICAL IMPORTANCE

This study supports the use of rectally administered levetiracetam in future studies of clinical effectiveness in the management of epileptic dogs.

SPOC1-mediated antiviral host cell response is antagonized early in human adenovirus type 5 infection

Little is known about immediate phases after viral infection and how an incoming viral genome complex counteracts host cell defenses, before the start of viral gene expression. Adenovirus (Ad) serves as an ideal model, since entry and onset of gene expression are rapid and highly efficient, and mechanisms used 24–48 hours post infection to counteract host antiviral and DNA repair factors (e.g. p53, Mre11, Daxx) are well studied. Here, we identify an even earlier host cell target for Ad, the chromatin-associated factor and epigenetic reader, SPOC1, recently found recruited to double strand breaks, and playing a role in DNA damage response. SPOC1 co-localized with viral replication centers in the host cell nucleus, interacted with Ad DNA, and repressed viral gene expression at the transcriptional level. We discovered that this SPOC1-mediated restriction imposed upon Ad growth is relieved by its functional association with the Ad major core protein pVII that enters with the viral genome, followed by E1B-55K/E4orf6-dependent proteasomal degradation of SPOC1. Mimicking removal of SPOC1 in the cell, knock down of this cellular restriction factor using RNAi techniques resulted in significantly increased Ad replication, including enhanced viral gene expression. However, depletion of SPOC1 also reduced the efficiency of E1B-55K transcriptional repression of cellular promoters, with possible implications for viral transformation. Intriguingly, not exclusive to Ad infection, other human pathogenic viruses (HSV-1, HSV-2, HIV-1, and HCV) also depleted SPOC1 in infected cells. Our findings provide a general model for how pathogenic human viruses antagonize intrinsic SPOC1-mediated antiviral responses in their host cells. A better understanding of viral entry and early restrictive functions in host cells should provide new perspectives for developing antiviral agents and therapies. Conversely, for Ad vectors used in gene therapy, counteracting mechanisms eradicating incoming viral DNA would increase Ad vector efficacy and safety for the patient.

Viruses have acquired functions that target and modulate host cell signaling and diverse regulatory cascades, leading to efficient viral propagation. During the course of productive infection, Ad gene products manipulate destruction pathways to prevent viral clearance or cell death prior to viral genome amplification and release of progeny. Recently, we reported that chromatin formation and cellular SWI/SNF chromatin remodeling processes play a key role in Ad transcriptional regulation. Here, we observe for the first time that SPOC1, identified as a regulator of DNA damage response and chromatin structure, plays an essential role in restricting Ad gene expression and progeny production. This host cell antiviral mechanism is efficiently counteracted by tight association with the major core protein pVII bound to the incoming viral genome. Subsequently, SPOC1 undergoes proteasomal degradation via the Ad E1B-55K/E4orf6-dependent, Cullin-based E3 ubiquitin ligase complex. We also show that other viruses from RNA and DNA families also induce efficient degradation of SPOC1. These analyses of evasion strategies acquired by viruses and other human pathogens should provide important insights into factors manipulating the epigenetic environment to potentially inactivate, or amplify host cell immune responses, since detailed molecular mechanisms and the full repertoire of cellular targets still remain elusive.

The neural correlates of perceptual load induced attentional selection: an fMRI study

The neural correlates of perceptual load induced attentional selection were investigated in an functional magnetic resonance imaging (fMRI) experiment in which attentional selection was manipulated through the variation of perceptual load in target search. Participants searched for a vertically or horizontally oriented bar among heterogeneously (the high load condition) or homogeneously (the low load condition) oriented distractor bars in the central display, which was flanked by a vertical or horizontal bar presented at the left or the right periphery. The search reaction times were longer when the central display was of high load than of low load, and were longer when the flanker was incongruent than congruent with the target. Importantly, the flanker congruency effect was manifested only in the low load condition, not in the high load condition, indicating that the perceptual load in target search determined whether the task-irrelevant flanker was processed. Imaging analyses revealed a set of fronto-parietal regions having higher activations in the high than in the low load condition. Anterior cingulate cortex (ACC) was more activated for the incongruent than for the congruent trials. Moreover, ACC and bilateral anterior insula were sensitive to the interaction between perceptual load and flanker congruency such that the activation differences between the incongruent and congruent conditions were significant in the low, but not in the high load condition. These results are consistent with the claim that ACC and bilateral anterior insula may exert executive control by selectively biasing processing in favor of task-relevant information and this biasing depends on the resources currently available to the control system.

OFF bipolar cells express distinct types of dendritic glutamate receptors in the mouse retina

Parallel representations of the visual world are already established at the very first synapse of the visual system. Cone photoreceptors, which hyperpolarize in response to light, forward the visual signal onto distinct types of ON and OFF cone bipolar cells (BCs). In the case of OFF BCs, the glutamatergic cone input is integrated by ionotropic glutamate receptors, giving rise to a sign-preserving mode of synaptic transmission. The combination of glutamate receptor (GluR) subunits, i.e. AMPA or kainate subunits, importantly contributes to shaping the OFF bipolar cells' distinct response properties. The mouse is one of the few mammals in which the (most likely) complete set of (five) retinal OFF BC types is identified. However, it is not clear which GluR subtypes are expressed by the different mouse OFF BC types. We addressed this question by combining immunolabeling, electrical whole-cell recordings and pharmacology, and present evidence that the different types of OFF BCs express distinct types of glutamate receptors: Type 1 BCs exclusively expressed AMPA receptors, whereas type 2 and type 3a BCs expressed kainate receptors of different subunit compositions. Additionally, we found that two OFF BC types (3b and 4) very likely express both AMPA and kainate receptors but, interestingly, the two receptor subunits were not co-localized at the same dendritic site. The complex, BC type-specific expression pattern of GluRs we describe here supports their essential role in establishing parallel pathways at the first synapse of the mouse visual system.

First Report of Pseudomonas cichorii Causing Leaf Spot of Stevia Detected in Florida

During a routine nursery inspection in Hernando County, Florida in July 2011, leaf spot symptoms were observed on the popular sugar substitute stevia (Stevia rebaudiana). Spots were roughly circular to irregular in shape, variable in size, and dark brown with a yellow halo. White to cream-colored, circular, convex, gram-negative bacterial colonies were isolated on nutrient agar and identified as Pseudomonas cichorii based on the LOPAT scheme (2). DNA from four individual colonies inoculated in nutrient broth was extracted using DNeasy columns (Qiagen Inc., Valencia, CA). The PCR-amplified product from four different genes, 16S rRNA (1.5 Kbp), gyrB (0.9 Kbp), rpoB (1.2 Kbp), and rpoD (0.7 Kbp), was sequenced (GenBank Accession Nos. JQ994483, JQ994484, JQ994485, and JQ994486). Nucleotide and translated amino acid sequences for each gene were compared to the nucleotide and protein databases, respectively. The best matches were always with P. cichorii with nucleotide identities ranging from 98 to 99% and amino acid identities from 99 to 100%. Four healthy stevia plants were spray inoculated with 20 ml of a 10⁸ CFU ml^-1 suspension prepared from a 24-hour-old culture, of which two were sprayed with carborundum (silicon carbide) immediately prior to inoculation. Two additional plants were sprayed with carborundum only or sterile tap water only and served as healthy controls. Symptoms began to develop 4 days after inoculation. Spots originated at the tips or edges of the leaves and enlarged over time. Enlarging lesions progressed to encompass the entire leaf, accompanied by water soaking, curling, and necrosis. Blighting typically spread down to the stem and caused dieback. The pathogen was successfully reisolated from the lesions and produced identical LOPAT scheme results. Based on the information collected, it is believed that this is the first confirmed report of bacterial leaf spot caused P. cichorii on stevia worldwide. This find is significant due to the rising popularity of stevia cultivation for its sweetness and medicinal properties (1). To our knowledge, stevia is not currently being grown commercially in Florida; however, there is commercial acreage being developed elsewhere in the United States. References: (1) D. Patil et al. Asian J. Pharm. Clin. Res. 5:1, 2011. (2) N. W. Schaad et al. Laboratory Guide for Identification of Plant Pathogenic Bacteria. 3rd Edition. The American Phytopathological Society. St. Paul, MN, 2001.

SPOC1 modulates DNA repair by regulating key determinants of chromatin compaction and DNA damage response

Survival time-associated plant homeodomain (PHD) finger protein in Ovarian Cancer 1 (SPOC1, also known as PHF13) is known to modulate chromatin structure and is essential for testicular stem-cell differentiation. Here we show that SPOC1 is recruited to DNA double-strand breaks (DSBs) in an ATM-dependent manner. Moreover, SPOC1 localizes at endogenous repair foci, including OPT domains and accumulates at large DSB repair foci characteristic for delayed repair at heterochromatic sites. SPOC1 depletion enhances the kinetics of ionizing radiation-induced foci (IRIF) formation after γ-irradiation (γ-IR), non-homologous end-joining (NHEJ) repair activity, and cellular radioresistance, but impairs homologous recombination (HR) repair. Conversely, SPOC1 overexpression delays IRIF formation and γH2AX expansion, reduces NHEJ repair activity and enhances cellular radiosensitivity. SPOC1 mediates dose-dependent changes in chromatin association of DNA compaction factors KAP-1, HP1-α and H3K9 methyltransferases (KMT) GLP, G9A and SETDB1. In addition, SPOC1 interacts with KAP-1 and H3K9 KMTs, inhibits KAP-1 phosphorylation and enhances H3K9 trimethylation. These findings provide the first evidence for a function of SPOC1 in DNA damage response (DDR) and repair. SPOC1 acts as a modulator of repair kinetics and choice of pathways. This involves its dose-dependent effects on DNA damage sensors, repair mediators and key regulators of chromatin structure.

Laurel Wilt, Caused by Raffaelea lauricola, is Confirmed in Miami-Dade County, Center of Florida's Commercial Avocado Production

Laurel wilt, caused by Raffaelea lauricola, threatens native and nonnative species in the Lauraceae in the southeastern United States, including the important commercial crop, avocado, Persea americana (2,4). Although the pathogen's vector, Xyleborus glabratus, was detected in Miami-Dade County, FL in January 2010, laurel wilt had not been reported (4). In February 2011, symptoms of the disease were observed on native swampbay, P. palustris, in Miami-Dade County (25°72'N, 80°48'W). Externally, foliage was brown, necrotic, and did not abscise; internally, sapwood was streaked with dark gray-to-bluish discoloration; and, in dead trees, holes of natal galleries of the vector from which columns of frass were attached were evident. On a semiselective medium for R. lauricola, a fungus with the pathogen's phenotype was isolated from symptomatic sapwood. Colonies were slow growing, light cream in color, with dendritic, closely appressed mycelium and often a slimy surface. A representative strain of the fungus was further identified with PCR primers for diagnostic small subunit (SSU) rDNA (1) and its SSU sequence (100% match, GenBank Accession No. JN578863). In each of two experiments, plants of 'Simmonds' avocado, the most important cultivar in Florida, were inoculated with three strains of the fungus, as described previously (3). Symptoms of laurel wilt developed in all inoculated plants and the fungus was recovered from each. After aerial and further ground surveys, additional symptomatic swampbay trees, some of which had defoliated, were detected in the vicinity of the original site. Since swampbay defoliates only a year or more after symptoms develop (4), the 2010 detection of X. glabratus may have coincided with an undetected presence of the disease. As of July 2011, a 6-km-diameter disease focus was evident in the area, the southernmost edge of which is 5 km from the nearest commercial avocado orchard. In August 2011, a dooryard avocado tree immediately north of the above focus was affected by laurel wilt, and an SSU sequence confirmed the involvement of R. lauricola (GenBank Accession No. JN613280). The outbreak of laurel wilt in Miami-Dade County represents a 150 km southerly jump in the distribution of this disease in the United States ( http://www.fs.fed.us/r8/foresthealth/laurelwilt/dist_map.shtml ) and is the first time this disease has been found in close proximity to Florida's primary commercial avocado production area. Approximately 98% of the state's commercial avocados, worth nearly $54 million per year, are produced in Miami-Dade County. Since effective fungicidal and insecticidal measures have not been developed for large, fruit-bearing trees, mitigation efforts will focus on the rapid identification and destruction of infected trees (3,4). References: (1) T. J. Dreaden et al. Phytopathology 98:S48, 2008. (2) S. W. Fraedrich et al. Plant Dis. 92:215, 2008. (3) R. C. Ploetz et al. Plant Dis. 95:977, 2011. (4) R. C. Ploetz et al. Recovery Plan for Laurel Wilt of Avocado. National Plant Disease Recovery System, USDA, ARS, 2011.

Dampening of blood-flow pulsatility along the carotid siphon: does form follow function?

BACKGROUND AND PURPOSE

The tortuous distal part of the ICA may have an attenuating effect on pulsatile arterial flow. We investigated local arterial blood flow patterns in the ICA proximal and distal to the carotid siphon to detect quantitative waveform changes.

MATERIALS AND METHODS

Arterial flow patterns were analyzed by using flow-sensitized 4D PC MR imaging (time-resolved 3D PCMR) at 3T in 17 healthy volunteers. Time-resolved blood flow velocities were extracted from the source data at the C4 and C7 segments of the ICA. PI, RI, and PA were calculated by using time-resolved flow volume. A linear mixed-effects model was applied to compare values at C4 and C7. Furthermore, 3D blood flow visualization was performed for all 34 ICAs.

RESULTS

PI, RI, and PA were significantly lower at the distal C7 segment compared with the proximal C4 segment of the ICA (P < .0001). Helical flow patterns were observed in 5 ICAs of 4 subjects.

CONCLUSIONS

Arterial flow patterns showed a significant reduction in PI, RI, and PA when compared distal to proximal to the carotid siphon. The observed attenuation of flow pulsatility is most likely related to the contorted shape of the distal ICA and may bear a protective effect for downstream cerebral vasculature.

Enhanced cartilage regeneration in MIA/CD-RAP deficient mice

Melanoma inhibitory activity/cartilage-derived retinoic acid-sensitive protein (MIA/CD-RAP) is a small soluble protein secreted from chondrocytes. It was identified as the prototype of a family of extracellular proteins adopting an SH3 domain-like fold. In order to study the consequences of MIA/CD-RAP deficiency in detail we used mice with a targeted gene disruption of MIA/CD-RAP (MIA−/−) and analyzed cartilage organisation and differentiation in in vivo and in vitro models. Cartilage formation and regeneration was determined in models for osteoarthritis and fracture healing in vivo, in addition to in vitro studies using mesenchymal stem cells of MIA−/− mice. Interestingly, our data suggest enhanced chondrocytic regeneration in the MIA−/− mice, modulated by enhanced proliferation and delayed differentiation. Expression analysis of cartilage tissue derived from MIA−/− mice revealed strong downregulation of nuclear RNA-binding protein 54-kDa (p54^nrb), a recently described modulator of Sox9 activity. In this study, we present p54^nrb as a mediator of MIA/CD-RAP to promote chondrogenesis. Taken together, our data indicate that MIA/CD-RAP is required for differentiation in cartilage potentially by regulating signaling processes during differentiation.

Gallium nitride electrodes for membrane-based electrochemical biosensors

We report on the deposition of planar lipid bilayers (supported membranes) on gallium nitride (GaN) electrodes for potential applications as membrane-based biosensors. The kinetics of the lipid membrane formation upon vesicle fusion were monitored by simultaneous measurements of resistance and capacitance of the membrane using AC impedance spectroscopy in the frequency range between 50 mHz and 50 kHz. We could identify a two-step process of membrane spreading and self-healing. Despite its relatively low resistance, the membrane can be modeled by a parallel combination of an ideal resistor and capacitor, indicating that the membrane efficiently blocks the diffusion of ions.

Long-term effects of chondrospheres on cartilage lesions in an autologous chondrocyte implantation model as investigated in the SCID mouse model

Microtraumata often lead to articular cartilage lesions. Due to the bradytrophic character of hyaline cartilage, these lesions are hardly repaired by the organism. Autologous chondrocyte implantation (ACI) was established for restoring isolated structural cartilage defects in knee joints. However, results are not always convincing. Human chondrocytes from patients undergoing total knee arthroplasty were cultured in monolayer followed by condensing single chondrocytes to spheroids (chondrospheres). The integrative capacity of chondrospheres was examined by implanting them into lesions in human articular cartilage specimens and co-implanting them into SCID mice. Mice were sacrificed after 4, 12 and 24 weeks. HE and safranin O staining as well as immunohistochemistry using anti-S100, anti-collagen I and II antibodies were performed and analyzed using semiquantitative scores. Integration of the chondrospheres with the (native) cartilage matrix was analyzed by determining the percentage of adhering surface. With respect to long-term stability, the chondrocytes within chondrospheres showed a typical chondrocytic morphology. Immunohistochemically, a high collagen II production was detected. Over a time period of 24 weeks, an increasing content of collagen type II, glycosaminoglycans and collagenous fibers were found. Importantly, the newly synthesized cartilaginous matrix integrated continuously with the native cartilage lesion border. In conclusion, the presented data demonstrate that chondrospheres are able to restore and conserve their phenotype for at least 24 weeks under in vivo conditions. Moreover, chondrospheres adhere to full-thickness cartilage defects and appear to produce a cartilaginous extracellular matrix which fuses with native cartilage thus generating an autologous cartilage-like repair tissue.

Role of the Netrin System of Repellent Factors on Synovial Fibroblasts in Rheumatoid Arthritis and Osteoarthritis

Changes in the expression of repellent factors, i.e., Netrins and their receptors, may be responsible for the invasive behavior of the synovial tissue cells in patients with rheumatoid arthritis (RA) and osteoarthritis (OA). This study was carried out to analyze the expression of Netrins and their receptors in synovial cells of patients with RA, OA, and control subjects without synovial inflammation. Quantitative RT-PCR was performed to measure the expression of Netrin-1, −3, −4, Neogenin, DCC, UNC5A-D. The influence of Netrin-1 on synovial fibroblasts (SF) was analyzed by determining proliferation, migration, and their ability to organize collagen. SF expressed all repellent factors of the Netrin family. When comparing SF of healthy donors to patients with RA and OA, a stronger expression of UNC5B (4 fold) and UNC5C (769 fold) in RA and OA was found, whereas expression of the other molecules revealed no significant differences. Treating the SF-cells with recombinant Netrin-1 resulted in inhibition of migration of RA- and OA-SFs whereas control cells were not affected. The stronger expression of UNC5B and UNC5C receptors might contribute to the disordered phenotype of RA- and OA-SFs. Addition of Netrin-1 reduces the migratory ability of SFs, potentially by repulsion, as seen in neuronal cells in embryonic development. Due to its function, Netrin-1 may constitute a novel target in the treatment of OA and RA.

[Case report--surgical therapy of a retroperitoneal liposarcoma weighing 45 kg]

Due to the late onset of symptoms, retroperitoneal liposarcoma are often diagnosed in advanced stages when adjacent organs have been infiltrated and the tumours have reached extensive sizes. Surgery remains the first choice of therapy. We report on the primary resection of a 45-kg liposarcoma that was removed en-bloc including the left kidney and descending colon with -tumour-free margins. Nine months later, the follow-up revealed a right-sided recurrence of the tumour, which was surgically removed including the right ureter. Since then, the patient has been without any signs of tumour recurrence or metastases. This report demonstrates that even extreme-ly large tumours can be removed safely and that the size is not a contraindication for primary surgical treatment. Local recurrence is common as seen in our case, and occurs even after R0 resection up to 10 years after the first operation. Recurrences should be surgically removed as this is the only treatment which has been shown to increase survival in even R1 and R2 situations.