Co-delivery of rhBMP-2 and zoledronic acid using calcium sulfate/hydroxyapatite carrier as a bioactive bone substitute to enhance and accelerate spinal fusion

Recombinant human bone morphogenetic protein-2 (rhBMP-2) has been FDA-approved for lumbar fusion, but supraphysiologic initial burst release due to suboptimal carrier and late excess bone resorption caused by osteoclast activation have limited its clinical usage. One strategy to mitigate the pro-osteoclast side effect of rhBMP-2 is to give systemic bisphosphonates, but it presents challenges with systemic side effects and low local bioavailability. The aim of this in vivo study was to analyze if posterolateral spinal fusion (PLF) could be improved by utilizing a calcium sulfate/hydroxyapatite (CaS/HA) carrier co-delivering rhBMP-2 and zoledronic acid (ZA). Six groups were allocated (CaS/HA, CaS/HA + BMP-2, CaS/HA + systemic ZA, CaS/HA + local ZA, CaS/HA + BMP-2 + systemic ZA, and CaS/HA + BMP-2 + local ZA). 10-week-old male Wistar rats, were randomly assigned to undergo L4-L5 PLF with implantation of group-dependent scaffolds. At 3 and 6 weeks, the animals were euthanized for radiography, μCT, histological staining, or biomechanical testing to evaluate spinal fusion. The results demonstrated that the CaS/HA biomaterial alone or in combination with local or systemic ZA didn't support PLF. However, the delivery of rhBMP-2 significantly promoted PLF. Combining systemic ZA with BMP-2 didn't enhance spinal fusion. Notably, the co-delivery of rhBMP-2 and ZA using the CaS/HA carrier significantly enhanced and accelerated PLF, without inhibiting systemic bone turnover, and potentially reduced the dose of rhBMP-2. Together, the treatment regimen of CaS/HA biomaterial co-delivering rhBMP-2 and ZA could potentially be a safe and cost-effective off-the-shelf bioactive bone substitute to enhance spinal fusion.

Adipocyte Precursor-Derived NRG1 Promotes Resistance to FGFR Inhibition in Urothelial Carcinoma

Aberrations of the fibroblast growth factor receptor (FGFR) family members are frequently observed in metastatic urothelial cancer (mUC), and blocking the FGF/FGFR signaling axis is used as a targeted therapeutic strategy for treating patients. Erdafitinib is a pan-FGFR inhibitor, which has recently been approved by the FDA for mUC with FGFR2/3 alterations. Although mUC patients show initial response to erdafitinib, acquired resistance rapidly develops. Here, we found that adipocyte precursors promoted resistance to erdafitinib in FGFR-dependent bladder and lung cancer in a paracrine manner. Moreover, neuregulin 1 (NRG1) secreted from adipocyte precursors was a mediator of erdafitinib resistance by activating human epidermal growth factor receptor 3 (ERBB3; also known as HER3) signaling, and knockdown of NRG1 in adipocyte precursors abrogated the conferred paracrine resistance. NRG1 expression was significantly downregulated in terminally differentiated adipocytes compared with their progenitors. Pharmacologic inhibition of the NRG1/HER3 axis using pertuzumab reversed erdafitinib resistance in tumor cells in vitro and prolonged survival of mice bearing bladder cancer xenografts in vivo. Remarkably, data from single-cell RNA sequencing revealed that NRG1 was enriched in platelet-derived growth factor receptor-A (PDGFRA) expressing inflammatory cancer-associated fibroblasts, which is also expressed on adipocyte precursors. Together, this work reveals a paracrine mechanism of anti-FGFR resistance in bladder cancer, and potentially other cancers, that is amenable to inhibition using available targeted therapies.

SIGNIFICANCE

Acquired resistance to FGFR inhibition can be rapidly promoted by paracrine activation of the NRG1/HER3 axis mediated by adipocyte precursors and can be overcome by the combination of pertuzumab and erdafitinib treatment. See related commentary by Kolonin and Anastassiou, p. 648.

Manufacture and Deformation Angle Control of a Two-Direction Soft Actuator Integrated with SMAs

In this contribution, the development of a 3D-printed soft actuator integrated with shape memory alloys (SMA) wires capable of bending in two directions is presented. This work discusses the design, manufacturing, modeling, simulation, and feedback control of the actuator. The SMA wires are encased in Polytetrafluoroethylene (PTFE) tubes and then integrated into the 3D-printed matrix made of thermoplastic polyurethane (TPU). To measure and control the deformation angle of the soft actuator, a computer vision system was implemented. Based on the experimental results, a mathematical model was developed using the system identification method and simulated to describe the dynamics of the actuator, contributing to the design of a controller. However, achieving precise control of the deformation angle in systems actuated by SMA wires is challenging due to their inherent nonlinearities and hysteretic behavior. A proportional-integral (PI) controller was designed to address this challenge, and its effectiveness was validated through real experiments.

Influence of the Scalpel Finishing Technique on Marginal Gap Formation in Class II Resin Composite Restorations

OBJECTIVES

Modern adhesives and composites allow the restoration of deep defects. In such cases, the matrix technique is particularly challenging, and excess composite is a common problem. Removing such overhangs with a scalpel has already been described as a substance preserving or selective finishing technique. Clinically, restoration margins may appear as a white line after scalpel finishing, and it is unclear whether this line represents a marginal gap and/or whether scalpel finishing promotes marginal gap formation. Therefore, the aim of this study was to investigate the influence of scalpel finishing of deep Class II composite restorations on marginal gap formation.

METHODS AND MATERIALS

Standardized mesioocclusal-distal (MOD) cavities were prepared and restored in 60 human molars randomly divided into six finishing protocol groups: G1, scalpels (SC); G2, oscillating files (OF); G3, finishing strips (FS); G4, scalpels and finishing strips (SC+FS); G5, scalpels and polishing discs (SC+PD); G6, polishing discs alone (PD, controls). The groups were additionally assigned to finishing and polishing in a phantom head (groups 1-4) or hand-held setting (groups 5-6) to simulate clinical and in-vitro research conditions, respectively. After restoration, artificial aging was performed by thermocycling (5-55°C, 2500 cycles) and mechanical loading (50 newtons (N) with 500,000 cycles) prior to scanning electron microscopy analysis of proximal restoration margin quality on the mesial and distal surfaces (n=120) of each tooth. Outcomes (perfect margin, marginal gap, overhang, marginal fracture) were statistically analyzed by t-test, Mann-Whitney U test, single-factor analysis of variance, post-hoc t-test, Kruskal-Wallis test and Dunn-Bonferroni correction for multiple group comparisons. Cohen's effect size d(Cohen) was calculated to show the strength of the relationship between variables.

RESULTS

Overall, marginal quality was significantly better in the hand-held setting (SC+PD and PD) than the phantom head setting (SC, OF, FS, SC+FS). The best marginal quality was achieved with oscillating files in the phantom head setting and with scalpels plus polishing discs in the hand-held setting. Marginal gaps occurred significantly more often with scalpels, but the proportion of gaps was very low and clinically insignificant. Finishing strips were the least effective instruments for removing overhangs but performed better in combination with scalpels.

CONCLUSIONS

Scalpel finishing can effectively and gently remove overhangs from enamel. However, blades should be used with caution as they can cut the dentin and cementum. Scalpel finishing does not lead to a clinically relevant increase in marginal gaps, but should be followed by polishing, whenever possible, to eliminate any marginal fractures that might be present.

Problem of implicit assumptions about left ventricular geometry in the calculation of myocardial mass by echocardiography – a validation study with cardiac magnetic resonance

Background/Introduction

Cardiac magnetic resonance imaging (CMR) is regarded as the reference method in assessing left ventricular (LV) myocardial mass. However, 2-dimensional echocardiography (Echo) is still used due to availability and practicability.

Purpose

We sought to assess measurements of LV myocardial mass from Echo exams and validate the results with CMR on a large cohort of patients.

Methods

We analyzed 357 patients who underwent clinically indicated CMR examinations and performed a standard Echo at the same day. In Echo, the commonly used Devereux formula (CUBE) was assessed for the calculation of LV mass: 0.8 × {1.04 × [([LV end-diastolic diameter + diastolic septum-thickness + posterior wall-thickness]3 − LV end-diastolic diameter3)]} + 0.6. Mass was indexed on body surface area (g/m2). Correlation (r), regression (R2) and Bland-Altman analysis were performed in order to assess bias between the two methods. Significance was defined as a 2-tailed P value <0.05.

Results

LV myocardial mass was measured in 345 patients with CMR and Echo. The median age was 61 years [19–79], 44% were female and CMR was performed due to coronary artery diseases (45%), suspected or florid myocarditis (31%) or further diagnosis of non-ischemic heart failure (24%). LV ejection fraction (EF) ranged between 13 and 71%. We found a significant relation of measurements for myocardial mass between Echo and CMR (R2=0.6, p<0.001) (Figure 1, left). However, there was a significant proportional bias (R2=0.47, p<0.001) depending in the amount of LV mass measured (Figure 1, right). As expected, the measurement bias correlated not only with the amount of mean wall-thickness (septum & posterior wall) from Echo, but also with LV end-diastolic diameter (r=−0.55 and −0.41, p<0.001 for all). Interestingly, the amount of LV EF correlated reversely with the proportional bias (r=0.34, p<0.001).

Conclusion

The results provided by our study, highlight the problem of implicit assumptions of LV geometry in the calculation of LV myocardial mass by Echo (CUBE) compared to CMR. Furthermore, the strongly biased differences between these two measurement methods are not negligible and warrant further investigation.

Funding Acknowledgement

Type of funding sources: None.

The automatic identification of left ventricular chambers and quantification of ejection fraction using a novel artificial intelligence-based system – a validation against cardiac magnetic resonance

Background/Introduction

Cardiac magnetic resonance imaging (CMR) is regarded as the reference method in assessing left ventricular (LV) ejection fraction (EF). However, 2-dimensional echocardiography (2D-Echo) is the most frequently used technique due to availability and practicability. The interpretation of 2D-Echo examinations depends on the user's expertise and may vary between different operators. A novel vendor-independent software based on artificial intelligence (AI) performs both, automated evaluation of 2D-Echo exams and calculations of LV EF in one workflow.

Purpose

We sought to assess the ability of the AI to automatically identify appropriate LV 4- and 2-chamber views (4CV) (2CV) from 2D-Echo exams and validate the resulting EF with CMR.

Methods

We consecutively enrolled 128 patients who underwent clinically indicated CMR examinations and performed a standard 2D-Echo at the same day. The server-based AI solution recognized the optimal LV 4CV and 2CV from 2D-Echo according to quality and depth criteria and automatically performed calculation of biplane EF by endocardial borderline detection. LV EF from CMR and AI were supervised by independent cardiologists blinded to the mutual results. Pearson's correlation (R) and Bland-Altman analysis with limits of agreement (LOA) were performed in order to assess bias between the two methods. Significance was defined as a 2-tailed P value <0.05.

Results

CMR was performed and LV EF was measured in all 128 patients. The median age was 60 years [20–86], 65% were males and CMR was performed due to coronary artery diseases (33%), suspected/florid myocarditis (20%) or further diagnosis of non-ischemic heart failure (47%). Eleven cases (9%) did not pass AI's criteria due to impaired acoustic window or poor 2D-Echo images. The AI system detected either 4CV or 2CV (ratio 1.2) in 13 patients (10%), and both 4CV and 2CV in 104 patients (81% overall feasibility) with a correct classification of 100%. For these 104 patients, excellent correlation was found for AI's biplane LV EF and LV EF from CMR with r=0.91 (p<0.001) (Figure 1, left). However, the absolute mean bias between AI and CMR was 3.5% (p<0.001) and LOAs were −10.6 and +17.5% (Figure 1, right).

Conclusion

The results provided by the AI-based software showed good capabilities and a perfect classification rate to identify 4CV and 2CV. In addition, the LV EF results were excellent compared to CMR, especially since our study did not include “echocardiographically” pre-selected patients. However, differences between AI and CMR measurements are not negligible and warrant further investigation.

Funding Acknowledgement

Type of funding sources: None.

Left ventricular ejection fraction – human vs artificial intelligence: quo vadis?

Background/Introduction

Two-dimensional echocardiography (Echo) is a feasible method for assessing left ventricular (LV) ejection fraction (EF) in daily practice. However, the interpretation of Echo exams depends on the user's expertise and may vary between different operators. A novel, vendor-neutral artificial intelligence (AI) performs both, automated evaluation of Echo exams and calculations of biplane LV EF in one workflow.

Purpose

We sought to assess the ability of the AI to automatically identify appropriate LV 4- and 2-chamber views (4CV) (2CV) from routine Echo examinations and compare the resulting biplane EF with conventional hand-tracing biplane Simpson method (Human).

Methods

We prospectively enrolled 311 patients who underwent clinically indicated Echo exams. Biplane LV EF was manually traced online on 4CV and 2CV by cardiologists (Human). After completion of the exam, the AI-based solution recognized the optimal LV 4CV and 2CV according to quality and depth criteria and automatically performed the calculation of biplane EF by endocardial borderline detection without Human's interaction. Spearman's correlation (R) and Bland-Altman analysis with limits of agreement (LOA) were assessed for bias between the two methods. In a subgroup of 20 patients, Echo exams were automatically reanalyzed by the AI, and conventional biplane Simpson of LV EF was performed by two cardiologists blinded to the previous results to determine intraclass correlation (ICC). Significance was defined as a 2-tailed p value <0.05.

Results

311 patients (median age 72 years [19–97]; 40% female) received an Echo for valvular heart disease, ischemic and non-ischemic heart failure or other indications (39, 31, 19 and 11%). 16 cases (5%) did not pass AI's criteria due to poor Echo imaging or impaired acoustic window of patients. In 53 patients (17%) either 4CV or 2CV were recognized, but the AI system successfully identified both 4CV and 2CV in 242 patients (overall feasibility 78%). For these 242 patients, correlation between AI and Human biplane LV EF was r=0.83 (p<0.001) (Figure 1 left). The absolute mean bias between methods was 5.2% (p<0.001) and absolute LOA ranged from −9.0 to +19.4% (Figure 1 right). ICC of LV EF by Human was 0.77 (p<0.001). The AI's ability to correctly re-/classify 4CV and 2CV was 100% with an ICC of 1 for fully automated LV EF measurements.

Conclusion

The results provided by the AI-based software showed very good capability to identify 4CV and 2CV and good LV EF result compared to Human manual tracings, especially since patients were not pre-selected. However, differences between AI and Human measurements are not negligible and warrant further investigations.

Funding Acknowledgement

Type of funding sources: None.

Numerical Investigation of the Orientability of Single Reinforcement Fibers in Polymer Matrices

Fiber-reinforced polymers are increasingly being used, especially in lightweight structures. Here, the effective adaptation of mechanical or physical properties to the necessary application or manufacturing requirements plays an important role. In this context, the alignment of reinforcing fibers is often hindered by manufacturing aspects. To achieve graded or locally adjusted alignment of different fiber lengths, common manufacturing technologies such as injection molding or compression molding need to be supported by the external non-mechanical process. Magnetic or electrostatic fields seem to be particularly suitable for this purpose. The present work shows a first simulation study of the alignment of magnetic particles in polymer matrices as a function of different parameters. The parameters studied are the viscosity of the surrounding polymer as a function of the focused processing methods, the fiber length, the thickness and permeability of the magnetic fiber coatings, and the magnetic flux density. The novelty of the presented works is in the development of an advanced simulation model that allows the simulative representation and reveal of the fluid–structure interaction, the influences of these parameters on the inducible magnetic torque and fiber alignment of a single fiber. Accordingly, the greatest influence on fiber alignment is caused by the magnetic flux density and the coating material.

OP0072 SINGLE CELL SEQUENCING REVEALS CLONALLY EXPANDED CYTOTOXIC CD4+ T CELLS IN THE JOINTS OF ACPA+ RA PATIENTS

Background:

CD4+ T cells with cytotoxic functions (CD4+ CTL) have gained attention in recent years. Accumulating evidence supports their importance in defense against human viral infections such as CMV1, EBV2, dengue3, HIV4, 5 and SARS-CoV-26. Moreover, expansion of so called CD28null cytotoxic CD4+ T cells have been reported in the blood of patients with rheumatic diseases such as rheumatoid arthritis (RA)7, myositis8 and vasculitis9 as well as in cardiovascular diseases10.

Objectives:

Here, we aimed to investigate the presence and clonal expansion of CD4+ CTL in the peripheral blood (PB) and synovial fluid (SF) of RA patients using single cell technologies.

Methods:

We assessed the expression of cytotoxic effector molecules and transcription factors in CD4+ T cells in synovial fluid (n=21) and paired peripheral blood (n=16) from ACPA- and APCA+ RA patients by multi-parameter flow cytometry. We performed single cell sequencing, in combination with 5´ TCRab sequencing, on purified CD4+ T cells from the peripheral blood (PB) and synovial fluid (SF) of ACPA+ RA patients (n=7).

Results:

Flow cytometry experiments show that Granzyme-B+ Perforin-1+ CD4+ CTL are significantly increased in the SF of ACPA+ RA patients as compared to ACPA- RA patients (p=0.0072). The presence of CD4+ CTL could be confirmed by single cell sequencing in SF of each ACPA+ RA patient tested (n=7). Moreover, we found that the adhesion G-protein coupled receptor GPR56 is selectively expressed on the recently described peripheral helper (TPH) T-cell subset11 and associates with the expression of tissue resident memory markers LAG-3, CXCR6 and CD69. In blood, we confirmed a previous report12 showing that GPR56 delineates cytotoxic CD4+ T cells. Finally, expanded TCR clones expressing cytotoxic effector molecules were identified in synovial fluid of ACPA+ RA patients and, for some patients, in their corresponding peripheral blood.

Conclusion:

We identified GPR56 as a marker of TPH cells in SF of ACPA+ RA patients that associates with tissue residency receptors. The combination of single cell sequencing and multi-parameter flow cytometry highlights the importance of CD4+ CTL in ACPA+ RA and suggests a potential therapeutic target (Figure 1).

References:

[1]Casazza J. P. et al., J Exp Med2006,203 (13), 2865-77.

[2]Landais E. et al., Blood2004,103 (4), 1408-16.

[3]Kurane I. et al. J Exp Med1989,170 (3), 763-75.

[4]Appay V. et al. J Immunol2002,168 (11), 5954-8.

[5]Juno J. A. et al. Front Immunol2017,8, 19.

[6]Meckiff B. J. et al. Cell2020,183 (5), 1340-1353 e16.

[7]Schmidt D. et al. J Clin Invest1996,97 (9), 2027-37.

[8]Fasth A. E. et al. J Immunol2009,183 (7), 4792-9.

[9]Moosig F. et al. Clin Exp Immunol1998,114 (1), 113-8.

[10]Sato K. et al. J Exp Med2006,203 (1), 239-50.

[11]Rao D. A., et al. Nature2017,542 (7639), 110-114.

[12]Peng Y. M. et al. J Leukoc Biol2011,90 (4), 735-40.

Acknowledgements:

We thank the patients who donated samples and the medical staff at the Rheumatology Clinic of Karolinska University Hospital. Julia Boström, Gloria Rostvall, and Susana Hernandez Machado are acknowledged for organizing the sampling, storage, and administration of biomaterial. This study is supported by grants from Dr. Margaretha Nilssons, the Nanna Svartz, the Ulla and Gustaf af Ugglas foundations and the Swedish association against rheumatism.

Disclosure of Interests:

Alexandra Argyriou: None declared, Marc H Wadsworth II Employee of: Pfizer, Inc, Cambridge, MA 02139, United States, Adrian Lendvai: None declared, Stephen Christensen Employee of: Pfizer, Inc, Cambridge, MA 02139, United States, Aase Hensvold: None declared, Christina Gerstner: None declared, Kellie Kravarik Employee of: Pfizer, Inc, Cambridge, MA 02139, United States, Aaron Winkler Employee of: Pfizer, Inc, Cambridge, MA 02139, United States, Vivianne Malmström: None declared, Karine Chemin: None declared

POS0348 GENETIC SUSCEPTIBILITY VARIANTS FOR RHEUMATOID ARTHRITIS ARE NOT ASSOCIATED WITH EARLY REMISSION; A MULTI-COHORT STUDY

Background:

Patients who achieve remission promptly could have a specific genetic risk profile that supports regaining immune tolerance. The identification of these genes could provide novel drug targets.

Objectives:

To test the association between RA genetic risk variants with achieving remission at 6 months.

Methods:

We computed genetic risk scores (GRS) comprising of the RA susceptibility variants1 and HLA-SE status separately in 4425 patients across eight datasets from inception cohorts. Remission was defined as DAS28CRP<2.6 at 6 months. Missing DAS28CRP values in patients were imputed using predictive mean matching by MICE. We first tested whether baseline DAS28CRP changed with increasing GRS using linear regression. Next, we calculated odds ratios for GRS and HLA-SE on remission using logistic regression. Heterogeneity of the outcome between datasets was mitigated by running inverse variance meta-analysis.

Results:

Evaluation of the complete dataset, baseline clinical variables did not differ between patients achieving remission and those who did not (Table 1). Distribution of GRS was consistent between datasets. Neither GRS nor HLA-SE was associated with baseline DAS2DAS (OR1.01; 95% CI 0.99-1.04). A fixed effect meta-analysis (Figure 1.) showed no significant effect of the GRS (OR 0.99; 95% CI 0.94-1.03) or HLA-SE (OR 0.8CRP87; 95% CI 0.75-1.01) on remission at 6 months.

Table 1.

Summary of the data separated by disease activity after 6 months.

allRemission at 6 monthsNo remission at 6 monthsN4425*15582430Age, mean (sd)55.38 (13.87)5517 (14.09)55.62 (13.59)Female %68.98%65.43%70.73%ACPA+ %61.94%63.53%61.67%Baseline DAS28, mean (sd)4.76 (1.22)4.47 (1.23)5.1 (1.15)

*not all patients had 6 months data

Conclusion:

In these combined cohorts, RA genetics risk variants are not associated with early disease remission. At baseline there was no difference in genetic risk between patients achieving remission or not. Studies encompassing other genetic variants are needed to elucidate the genetics of RA remission.

References:

[1]Knevel R et al. Sci Transl Med. 2020;12(545):eaay1548.

Acknowledgements:

This project has received funding from the Innovative Medicines Initiative 2 Joint Undertaking under grant agreement No 777357, RTCure.

This project has received funding from Pfizer Inc.

Disclosure of Interests:

Samantha Jurado Zapata: None declared, Marc Maurits: None declared, Yann Abraham Employee of: Pfizer, Erik van den Akker: None declared, Anne Barton: None declared, Philip Brown: None declared, Andrew Cope: None declared, Isidoro González-Álvaro: None declared, Carl Goodyear: None declared, Annette van der Helm - van Mil: None declared, Xinli Hu Employee of: Pfizer, Thomas Huizinga: None declared, Martina Johannesson: None declared, Lars Klareskog: None declared, Dennis Lendrem: None declared, Iain McInnes: None declared, Fraser Morton: None declared, Caron Paterson: None declared, Duncan Porter: None declared, Arthur Pratt: None declared, Luis Rodriguez Rodriguez: None declared, Daniela Sieghart: None declared, Paul Studenic: None declared, Suzanne Verstappen: None declared, Leonid Padyukov: None declared, Aaron Winkler Employee of: Pfizer, John D Isaacs: None declared, Rachel Knevel Grant/research support from: Pfizer

Interceptive use of pendulum for advance resolution of class II patient: a guided eruption plan to reduce stress on permanent teeth root

Use of the so-called distalizing mechanics is a common treatment to correct class II malocclusion. One of the first appliances made for molar distalization was the pendulum, which resulted immediately efficient. The knowledge of pendulum efficacy, in regards to distalizing treatment in adolescence, has guided the research to analyze pendulum effect in childhood: checking the pre-eruptive, natural and distal movement of upper second premolar following first upper molar distalization in order to obtain an advance resolution on Angle's Class II patient, limited treatment time, reduced periodontal inflammation and stress on permanent teeth root. A pilot study testing the possibility of a prospective study was necessary on 6 patients treated following an accurate protocol (6 months and 1-year Rx control) and 6 patient control after one year. Statistical analysis by T-Test was done. Oral hygiene controls every month were done. Second upper bicuspid vertical (1.6mm) and sagittal (2.5mm) movement mean values allow to emphasize a distal variation of tooth axis inclination of treatment group than control group, and a second upper bicuspid distal departure from "gubernaculus dentis" of second deciduous molar in treated patients. Periodontal inflammation appears inexistent on second and first upper premolar germs after the comparison between RX exam of treatment and control groups because of exploiting deciduous teeth. Besides periodontal inflammation and teeth root stress on first upper molar of treatment group, after RX analysis, results were limited compared to control groups because of the advanced orthodontic interceptive treatment during a previous stage of first upper molar root development.

The complexity of surface acoustic wave fields used for microfluidic applications

Using surface acoustic waves (SAW) for the agitation and manipulation of fluids and immersed particles or cells in lab-on-a-chip systems has been state of the art for several years. Basic tasks comprise fluid mixing, atomization of liquids as well as sorting and separation (or trapping) of particles and cells, e.g. in so-called acoustic tweezers. Even though the fundamental principles governing SAW excitation and propagation on anisotropic, piezoelectric substrates are well-investigated, the complexity of wave field effects including SAW diffraction, refraction and interference cannot be comprehensively simulated at this point of time with sufficient accuracy. However, the design of microfluidic actuators relies on a profound knowledge of SAW propagation, including superposition of multiple SAWs, to achieve the predestined functionality of the devices. Here, we present extensive experimental results of high-resolution analysis of the lateral distribution of the complex displacement amplitude, i.e. the wave field, alongside with the electrical S-parameters of the generating transducers. These measurements were carried out and are compared in setups utilizing travelling SAW (tSAW) excited by single interdigital transducer (IDT), standing SAW generated between two IDTs (1DsSAW, 1D acoustic tweezers) and between two pairs of IDTs (2DsSAW, 2D acoustic tweezers) with different angular alignment in respect to pure Rayleigh mode propagation directions and other practically relevant orientations. For these basic configurations, typically used to drive SAW-based microfluidics, the influence of common SAW phenomena including beam steering, coupling coefficient dispersion and diffraction on the resultant wave field is investigated. The results show how tailoring of the acoustic conditions, based on profound knowledge of the physical effects, can be achieved to finally realize a desired behavior of a SAW-based microacoustic-fluidic system.

FRI0100 COMPARISON OF PATIENTS (PTS) WITH RHEUMATOID ARTHRITIS (RA) AMONG DISEASE ACTIVITY CATEGORIES AFTER 6 MONTHS OF TREATMENT WITH A TUMOUR NECROSIS FACTOR INHIBITOR (TNFI): RESULTS FROM THE CORRONA® RA REGISTRY

Background:

Targeting remission (REM) or low disease activity (LDA) is a widely accepted treatment strategy for RA. However, there are limited data on the proportion of pts who achieve these targets, or remain in moderate (MDA) or high disease activity (HDA) following advanced therapy.

Objectives:

To estimate the proportion of RA pts in disease activity states (REM, LDA, MDA, and HDA) who were biologic-naïve at initiation and had continuous treatment with a TNFi for 6–12 months in the Corrona RA registry.

Methods:

Eligible pts were aged ≥18 years, biologic-naïve, initiated TNFi treatment between January 1, 2010 and July 31, 2019, and had continuous use of a TNFi for 6–12 months. Disease activity was defined based on Clinical Disease Activity Index (CDAI) at the visit closest to 6-month follow-up: REM, ≤2.8; LDA, >2.8–10; MDA, >10–22; and HDA, >22. Disease characteristics, disease activity measures, and pt-reported outcomes (PROs) were reported at TNFi initiation and at the 6-month follow-up visit.

Results:

2586 biologic-naïve pts who initiated a TNFi and had continuous use for 6–12 months were included. At TNFi initiation, 167 (6%) were in REM, 479 (19%) had LDA, 907 (35%) had MDA, and 1033 (40%) had HDA. After 6–12 months of treatment, 563 (21.8%) were in REM, 923 (35.7%) had LDA, 674 (26.1%) had MDA, and 426 (16.5%) had HDA. Pts with HDA/MDA at 6–12 months were more likely to have a history of hypertension (32.7% HDA; 34.0% MDA; vs 23.6% REM) and had higher mean body mass index (BMI) (30.9 HDA; 31.1 MDA; vs 29.0 REM) at baseline compared with pts in REM. Disease activity measures and PROs were worse in pts with MDA and HDA vs LDA and REM after 6–12 months (Table). Pt Global Assessment was higher than Physician Global Assessment across all groups.

Conclusion:

While 57.4% of pts who initiated a TNFi experienced a favorable outcome, >40% required additional or alternative intervention to achieve REM/LDA. Pts who remained in MDA/HDA continued to have an inadequate response to TNFi (as measured by disease activity measures and PROs) after 6–12 months of treatment compared with those who achieved REM/LDA.

Table

Summary of disease activity measures and PROs in previously biologic-naïve pts at the 6–12-month follow-up visit, stratified by disease activity category at the 6–12-month follow-up visit

Characteristics at 6–12 months, mean (standard deviation)Disease activity category at 6–12 monthsREM (n=563)LDA (n=923)MDA (n=674)HDA (n=426)CDAI1.2 (0.8)6.2 (2.1)15.4 (3.4)32.7 (9.2)Tender joint count (28)0.1 (0.3)1.0 (1.3)4.3 (3.3)13.4 (7.0)Swollen joint count (28)0.1 (0.3)1.1 (1.6)4.0 (3.6)9.1 (5.9)C-reactive protein6.4 (22.7)7.0 (10.6)11.1 (19.9)12.6 (22.1)Modified health assessment questionnaire0.1 (0.2)0.3 (0.4)0.5 (0.5)0.8 (0.5)Pt global assessment6.6 (6.8)28.6 (20.9)43.7 (25.7)58.0 (22.7)Physician global assessment3.6 (4.3)12.1 (10.4)27.4 (15.9)44.9 (19.8)Pt pain assessment8.7 (11.0)30.3 (23.5)46.1 (27.0)59.9 (24.4)Pt fatigue assessment15.7 (19.2)34.5 (26.6)48.3 (28.0)59.4 (27.5)Morning stiffness (min)16.5 (36.5)55.4 (146.3)96.9 (197.5)143.6 (260.0)

Disclosure of Interests:

Joel M Kremer Shareholder of: May own stocks and opinions, Grant/research support from: Research and consulting fees from AbbVie Inc., Consultant of: AbbVie, Amgen, BMS, Genentech, Inc., Gilead, GSK, Lilly, Pfizer, Regeneron and Sanofi, Employee of: Corrona, LLC employee, Anne Winkler Consultant of: AbbVie, Pfizer, and Novratis, Speakers bureau: AbbVie, Janssen, Sanofi, Genentech, Celgene, Eli Lilly, and Novartis., Laura Anatale-Tardiff Employee of: Corrona, LLC employee, Robert McLean Employee of: Corrona, LLC, Ying Shan Employee of: Corrona, LLC employee, Page Moore Employee of: Corrona, LLC employee, Namita Tundia Shareholder of: May own stocks and options, Employee of: AbbVie employee, Jessica Suboticki Shareholder of: AbbVie Inc., Employee of: AbbVie Inc., John Tesser Consultant of: Sanofi/Regeneron, Speakers bureau: Sanofi/Regeneron

THU0032 MODIFIED PEPTIDES AS A NOVEL IMMUNOTHERAPY FOR RHEUMATOID ARTHRITIS

Background:

Rheumatoid arthritis (RA) is a highly prevalent and severe systemic autoimmune disease associated with permanent disability and strong socio-economic burdens. Currently, there is no therapeutic treatment and RA patients rely on lifelong, costly treatments. Imcyse develops modified peptides eliciting antigen specific cytolytic CD4 T cells (cCD4+) that induce apoptosis of antigen presenting cells (APC) in a contact dependent manner. cCD4+ also induce apoptosis of autoantigen-specific bystander T-cells, activated by the same APC thus eliminating the risk of general immunosuppression. Peptides consist of MHC class II T cell epitopes of a target autoantigen modified in their flanking region by the addition of an amino acid sequence containing a thiol-disulphide oxidoreductase active motif1.

Objectives:

The goal of this study was to synthesize modified peptides from a target RA autoantigen and test their potency to generatein vitrospecific and cytolytic CD4+ T cells from RA patients.

Methods:

We designed modified peptides from a target RA autoantigen after in silico and in vitro assessment to identify MHC II core binding region, HLA class II binding capacities and physiochemical properties.

CD4+ T cells were purified from PBMC of a newly diagnosed seropositive RA patient and co-cultured with autologous APC in the presence of the modified peptide. The CD4+ T cells were restimulated periodically. Peptide’s ability to generate specific CD4+ T cells was evaluated by flow cytometric analysis of the expression of surface activation marker CD154 (CD40L). The peptide specific CD4+ T cell lines were sorted based on their surface CD154 expression. Their pro-apoptotic activity was assessed after overnight (O/N) co-culture of CD4+ T cells with fluorescent tracer labelled autologous lymphoblastoid cells lines (LCL). Flow cytometry quantification of LCL apoptosis was measured by annexin V staining. MHC II restriction of CD4+ T cells was demonstrated by the addition of blocking antibodies against HLA-DR, DP or DQ molecules.

Results:

CD4+ T cells were in vitro expanded after six consecutive stimulations with the peptide. We investigated their specificity by flow cytometry and showed that 69% of CD4+ T cells that were stimulated O/N in the presence of the peptide expressed the activation marker CD154 versus 29% of CD4+ T cells that were stimulated in its absence. These cells were sorted based on CD154 expression following specific stimulation. Cell enrichment was then assessed by flow cytometric analysis. Data showed that more than 91% (background 3%) were peptide specific based on CD154 expression.

After co-culture of CD4+ T cells with LCL, in independent experiments, Annexin V binding was detected on peptide loaded LCL, ranging from 69% to 89%, while when LCL were kept unloaded these values were between 30% and 55%, respectively, indicating that when specifically activated, these CD4+ T cells had pro-apoptotic activity. When both the peptide and blocking antibodies against HLA-DR, DP or DQ molecules added in the co-culture the pro-apoptotic activity was inhibited by 68%, 20% and 25%, respectively.

Conclusion:

The preliminary but very promising data show that our modified peptide generates peptide-specific CD4+ T cells with lytic properties that lyse target APC in an HLA class II specific manner. Our plan is to show that these CD4+ T cells can also induce apoptosis in bystander T cells and to further validate our results in additional RA donors.

References:

[1]Carlier, V. A., Vanderelst, L., Janssens, W. & Jacquemin, M. G. Increased Synapse Formation Obtained by T Cell Epitopes Containing a CxxC Motif in Flanking Residues Convert CD4 + T Cells into Cytolytic Effectors.7, (2012).

Disclosure of Interests:

Eleni Araklioti Grant/research support from: This work was supported by Pfizer Inc. and by Walloon Region, Ludivine Herman Grant/research support from: This work was supported by Pfizer Inc. and by Walloon Region, Ngoc Quynh Nhu Nguyen Grant/research support from: This work was supported by Pfizer Inc. and by Walloon Region, Roxana Roohi Ahangarani Grant/research support from: This work was supported by Pfizer Inc. and by Walloon Region, Milos Erak Grant/research support from: This work was supported by Pfizer Inc. and by Walloon Region, Bernard Lauwerys: None declared, Patrick Durez Speakers bureau: AbbVie, Bristol-Myers Squibb, Celltrion, Eli Lilly, Pfizer, Sanofi, Vincent Geenen: None declared, Aaron Winkler Shareholder of: Shareholder of Pfizer, Inc, Employee of: Full time employee of Pfizer, Inc, Marcelle Van Mechelen Grant/research support from: This work was supported by Pfizer Inc. and by Walloon Region, Luc Vander Elst Grant/research support from: This work was supported by Pfizer Inc. and by Walloon Region, Vincent Carlier Grant/research support from: This work was supported by Pfizer Inc. and by Walloon Region

Schistocytic anaemia, severe thrombocytopenia, and renal dysfunction: thrombotic microangiopathy due to severe acquired ADAMTS-13 deficiency

We present the case of a woman (age: 64 years) with acute thrombotic microangiopathy due to severe acquired ADAMTS-13 (von Willebrand factor-cleaving protease) deficiency. She was successfully treated with plasma exchange therapy and glucocorticosteroids. She relapsed seven months later, and splenectomy led to lasting remission.

Pathomechanisms of thrombotic thrombocytopenic purpura, especially the role of ADAMTS-13, are discussed and therapeutic measures outlined.

[Phonemic balance of the Freiburg monosyllabic speech test]

BACKGROUND

ISO 8253-3 [4] describes the requirements for speech tests with respect to their phonemic balance. The fulfillment of these requirements by the Freiburg monosyllabic speech test were examined.

METHODS

The Freiburg monosyllables were phonologically transcribed and analyzed with respect to their structural types, vowels and consonants, as well as phonological classes, and compared to reference values.

RESULTS

The phonemic distribution of the Freiburg monosyllables differs slightly from the reference values for the German language. The differences are presumably related to the restriction to monosyllabic substantives. Most test lists (except for 12) contain similar proportions of different phonem classes for vowel and consonants according to Hahlbrock and ISO 8253-3 [4].

CONCLUSION

The deviations of test lists 5, 11, and 15 in a study for perceptual equivalence cannot be explained by phonemic imbalance in comparison to other test lists. Only the lower recognition rates for test list 12 might be explained by its deviant phonemic distribution.

[Test-retest reliability of the Freiburg monosyllabic speech test]

BACKGROUND

ISO 8253-3 describes the requirements for speech tests used in audiology. One aspect is the test-retest reliability, which was here examined for the Freiburg monosyllabic speech test.

METHODS

Speech recognition scores were examined for 30 listeners with normal hearing ability. All 20 lists of the Freiburg monosyllabic speech test were tested at four different presentation levels. The retest was carried out 7-9 months later.

RESULTS

The test-retest reliability of the Freiburg monosyllabic speech test in this study is between 13 percentage points for a speech recognition score of 95 %, and 24 percentage points for a speech recognition score of 39 %. The measurement accuracy can be estimated using binomial distribution.

CONCLUSION

The reproducibility of the results is limited by the small number of test items (20 words) in each list. This does not fulfill the requirements for speech tests in diagnostics and rehabilitation. An improvement of the test-retest reliability can be achieved using several test lists.

[Evaluation of the perceptual equivalence of test lists in the Freiburg monosyllabic speech test]

BACKGROUND

In the past, the perceptual balance of test lists for the Freiburg monosyllabic speech test (FBE) was frequently evaluated without producing consistent results. Until now, the studies used very diverse methods and did not accurately follow the standardized specifications. In this study, therefore, the perceptual equivalence of test lists was verified with a large group of participants according to the standard ISO EN 8253-3.

METHODS

A total of 160  suitable otologically normal subjects were recruited at two institutions, each of whom listened to all test lists of the FBE using predefined measurement conditions. The subjects were divided in three groups depending on the transducer used for test list presentation (headphones "HDA 200" and "TDH 39", as well as free-field loudspeaker, "FF"). Lists that deviated were identified using the approaches specified in the standard.

RESULTS

The reference curve for FBE was not met by any group. While the "HDA 200" group indicated 4.6 dB lower thresholds, results for the "TDH 39" and "FF" groups showed 1.2 and 2.5 dB higher thresholds, respectively. For an average speech recognition score of 44.3 %, test lists 5, 11, 12, and 15 lay outside the calculated tolerance range of 4.5 to -4.4 percent points. The same lists also deviated when calculating discrimination functions and therefore do not fulfill the criteria for perceptual equivalence.

DISCUSSION

In the future, lists identified as deviating from the norm should not be used. The results of this study only partly agree with results from former studies.

Compact SAW aerosol generator

In this work, we discuss and demonstrate the principle features of surface acoustic wave (SAW) aerosol generation, based on the properties of the fluid supply, the acoustic wave field and the acoustowetting phenomena. Furthermore, we demonstrate a compact SAW-based aerosol generator amenable to mass production fabricated using simple techniques including photolithography, computerized numerical control (CNC) milling and printed circuit board (PCB) manufacturing. Using this device, we present comprehensive experimental results exploring the complexity of the acoustic atomization process and the influence of fluid supply position and geometry, SAW power and fluid flow rate on the device functionality. These factors in turn influence the droplet size distribution, measured here, that is important for applications including liquid chromatography, pulmonary therapies, thin film deposition and olfactory displays.

[Impact of a Senso-Motoric Intervention in COPD-Patients Participating in an Outpatient Pulmonary Rehabilitation Program: A Randomized Controlled Trial]

Objective Exercise training provides a cornerstone of pulmonary rehabilitation (PR) in COPD-patients. However, the components of the training are not yet fully investigated. We conducted a randomized controlled trial to investigate the effectiveness of a sensory-motoric training (SMT) in comparison to a conventional strength training (KT) according to the physical performance. Patients and Methods: 43 COPD patients were randomized and participated either in the intervention group (SMT = 30 minutes SMT per day) or in the control group (KT = 30 minutes KT per day). The SMT was performed as circuit training with five stations. The primary endpoint was the difference between T1 (start of the PR) and T2 (end of the PR) in 5-Times Sit-to-stand test (5-STST) in the intergroup comparison. Secondary endpoints were the intra- and intergroup comparisons of T1 and T2 in the 6-Minute Walk Test (6-MWT), COPD Assessment Test (CAT), St. George Respiratory Questionnaire (SGRQ), Hospital Anxiety- and Depression Scale (HADS) and in lung function. Results No significant differences were seen in the results of the 5-STST between the groups. Likewise, in the 6-MWT, SGRQ, CAT, HADS and lung function. The intragroup comparison between T1 and T2 showed significant differences in 5-STST, 6-MWT, SGRQ, CAT and HADS in both groups. The differences in lung function were not significantly, neither in the inter- nor in the intragroup comparison. Conclusion Similarly to a conventional strength training improvements in exercise capacity could be achieved with a SMT during PR in COPD patients. Further studies are necessary to define the role of the SMT in regards to postural control.

Temperature and layer thickness dependent in situ investigations on epindolidione organic thin-film transistors

We report on in situ performance evaluations as a function of layer thickness and substrate temperature for bottom-gate, bottom-gold contact epindolidione organic thin-film transistors on various gate dielectrics. Experiments were carried out under ultra-high vacuum conditions, enabling quasi-simultaneous electrical and surface analysis. Auger electron spectroscopy and thermal desorption spectroscopy (TDS) were applied to characterize the quality of the substrate surface and the thermal stability of the organic films. Ex situ atomic force microscopy (AFM) was used to gain additional information on the layer formation and surface morphology of the hydrogen-bonded organic pigment. The examined gate dielectrics included SiO2, in its untreated and sputtered forms, as well as the spin-coated organic capping layers poly(vinyl-cinnamate) (PVCi) and poly((±)endo,exo-bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid, diphenylester) (PNDPE, from the class of polynorbornenes). TDS and AFM revealed Volmer-Weber island growth dominated film formation with no evidence of a subjacent wetting layer. This growth mode is responsible for the comparably high coverage required for transistor behavior at 90-95% of a monolayer composed of standing molecules. Surface sputtering and an increased sample temperature during epindolidione deposition augmented the surface diffusion of adsorbing molecules and therefore led to a lower number of better-ordered islands. Consequently, while the onset of charge transport was delayed, higher saturation mobility was obtained. The highest, bottom-contact configuration, mobilities of approximately 2.5 × 10-3cm2/Vs were found for high coverages (50 nm) on sputtered samples. The coverage dependence of the mobility showed very different characteristics for the different gate dielectrics, while the change of the threshold voltage with coverage was approximately the same for all systems. An apparent decrease of the mobility with increasing coverage on the less polar PNDPE was attributed to a change in molecular orientation from upright standing in the thin-film phase to tilted in the bulk phase. From temperature-dependent mobility measurements we calculated activation barriers for the charge transport between 110 meV and 160 meV, depending on the dielectric configuration.

Optimizing pentacene thin-film transistor performance: Temperature and surface condition induced layer growth modification

In this work we present in situ electrical and surface analytical, as well as ex situ atomic force microscopy (AFM) studies on temperature and surface condition induced pentacene layer growth modifications, leading to the selection of optimized deposition conditions and entailing performance improvements. We prepared p++-silicon/silicon dioxide bottom-gate, gold bottom-contact transistor samples and evaluated the pentacene layer growth for three different surface conditions (sputtered, sputtered + carbon and unsputtered + carbon) at sample temperatures during deposition of 200 K, 300 K and 350 K. The AFM investigations focused on the gold contacts, the silicon dioxide channel region and the highly critical transition area. Evaluations of coverage dependent saturation mobilities, threshold voltages and corresponding AFM analysis were able to confirm that the first 3-4 full monolayers contribute to the majority of charge transport within the channel region. At high temperatures and on sputtered surfaces uniform layer formation in the contact-channel transition area is limited by dewetting, leading to the formation of trenches and the partial development of double layer islands within the channel region instead of full wetting layers. By combining the advantages of an initial high temperature deposition (well-ordered islands in the channel) and a subsequent low temperature deposition (continuous film formation for low contact resistance) we were able to prepare very thin (8 ML) pentacene transistors of comparably high mobility.

[Preliminary Short-term Results of an All-day Outpatient Pulmonary Rehabilitation Program in an Acute Hospital on Patients with Mild to Very Severe COPD]

INTRODUCTION

Positive effects of pulmonary rehabilitation on chronic obstructive pulmonary disease (COPD) are well known, and inpatient rehabilitation programs are the preferred modality in Germany. In this paper, we report on the recent results of a daily outpatient rehabilitation program offered at an acute hospital, the first of this kind in Germany. It is not known whether this kind of rehabilitation is an effective approach.

METHODS

32 consecutive COPD patients GOLD-stage II-IV, phenotype B-D (mean 64.5±21.9 years; 18 male, 14 female) completed a rehabilitation program of 19 (15-21) days conducted according to the recommendations of the National Accociation for Rehabilitation. In this prospective observational study, data (walking distance in the 6-MWD, BODE-Index, HADS-, BDI/TDI-, CAT-questionnaire) were collected at the beginning (T1) and at the end (T2) of the program and the results are presented in a pre- vs. post-analysis.

RESULTS

We found significant positive effects for most of the measured parameters, except for body plethysmography, diffusion capacity and blood gas. Especially the increase in the 6 min walking distance (6-MWD) was remarkable (T1: 485.78±158.24, T2: 527.97±146.75 m, p=0.0212). There were no adverse events or complications. All participants were able to complete the program properly.

CONCLUSION

Most of the measured parameters in COPD patients with stage II or worse disease improved significantly during the comprehensive outpatient rehabilitation program. A limitation of this study is the small number of cases, and further conclusions can only be made after examining a larger sample. The setting of this rehabilitation program in an acute hospital seems to be meaningful in an organisational and structural sense.

The effect of grape seed and grape marc meal extract on milk performance and the expression of genes of endoplasmic reticulum stress and inflammation in the liver of dairy cows in early lactation

During the periparturient phase, cows are typically in an inflammation-like condition, and it has been suggested that inflammation associated with the development of stress of the endoplasmic reticulum (ER) in the liver contributes to the development of fatty liver syndrome and ketosis. In the present study, we investigated the hypothesis that feeding grape seed and grape marc meal extract (GSGME) as a plant extract rich in flavonoids attenuates inflammation and ER stress in the liver of dairy cows. Two groups of cows received either a total mixed ration as a control diet or the same total mixed ration supplemented with 1% of GSGME over the period from wk 3 prepartum to wk 9 postpartum. Dry matter intake during wk 3 to 9 postpartum was not different between the 2 groups. However, the cows fed the diet supplemented with GSGME had an increased milk yield and an increased daily milk protein yield. Cows supplemented with GSGME moreover had a significantly reduced mRNA abundancy of fibroblast growth factor (FGF) 21, a stress hormone induced by various stress conditions, in the liver in wk 1 and 3 postpartum. In contrast, mRNA abundances of a total of 3 genes involved in inflammation and 14 genes involved in ER stress response, as well as concentrations of triacylglycerols and cholesterol, in liver samples of wk 1 and 3 postpartum did not differ between the 2 groups. Overall, this study shows that supplementation of GSGME did not influence inflammation or ER stress in the liver but increased milk yield, an effect that could be due to effects on ruminal metabolism.

SAW-based fluid atomization using mass-producible chip devices

Surface acoustic wave (SAW)-based fluid atomizers are ideally suited to generate micrometer-sized droplets without any moving parts or nozzles. Versatile application fields can be found for instance in biomedical, aerosol or thin film technology, including medical inhalators or particle deposition for advanced surface treatment. Such atomizers also show great potential for on-chip integration and can lead to economic production of hand-held and even disposable devices, with either a single functionality or integrated in more complex superior systems. However, this potential was limited in the past by fluid supply mechanisms inadequate for mass production, accuracy and reliability. In this work, we briefly discuss existing fluid supply methods and demonstrate a straightforward new approach suited for reliable and cost-effective mass-scale manufacturing of SAW atomizer chips. Our approach is based on a fluid supply at the boundary of the acoustic beam via SU-8 microchannels produced by a novel one-layer/double-exposure photolithography method. Using this technique, we demonstrate precise and stable fluid atomization with almost ideal aerosol plume geometry from a dynamically stabilized thin fluid film. Additionally, we demonstrate the possibility of in situ altering the droplet size distribution by controlling the amount of fluid available in the active region of the chip.

In situ preparation, electrical and surface analytical characterization of pentacene thin film transistors

The fabrication of organic thin film transistors with highly reproducible characteristics presents a very challenging task. We have prepared and analyzed model pentacene thin film transistors under ultra-high vacuum conditions, employing surface analytical tools and methods. Intentionally contaminating the gold contacts and SiO2 channel area with carbon through repeated adsorption, dissociation, and desorption of pentacene proved to be very advantageous in the creation of devices with stable and reproducible parameters. We mainly focused on the device properties, such as mobility and threshold voltage, as a function of film morphology and preparation temperature. At 300 K, pentacene displays Stranski-Krastanov growth, whereas at 200 K fine-grained, layer-like film growth takes place, which predominantly influences the threshold voltage. Temperature dependent mobility measurements demonstrate good agreement with the established multiple trapping and release model, which in turn indicates a predominant concentration of shallow traps in the crystal grains and at the oxide-semiconductor interface. Mobility and threshold voltage measurements as a function of coverage reveal that up to four full monolayers contribute to the overall charge transport. A significant influence on the effective mobility also stems from the access resistance at the gold contact-semiconductor interface, which is again strongly influenced by the temperature dependent, characteristic film growth mode.