Revised contraindications for the use of non-medical WB-electromyostimulation. Evidence-based German consensus recommendations

Whole-body electromyostimulation has proven to be a highly effective alternative to conventional resistance-type exercise training. However, due to adverse effects in the past, very extensive contraindications have been put in place for the commercial, non-medical WB-EMS market. Considering recent positive innovations e.g., federal regulation, mandatory trainer education, revised guidelines, and new scientific studies on WB-EMS application, we believe that a careful revision of the very restrictive contraindications on WB-EMS is needed. This applies all the more because many cohorts with limited options for conventional exercise have so far been excluded. During a first meeting of an evidence-based consensus process, stakeholders from various backgrounds (e.g., research, education, application) set the priorities for revising the contraindications. We decided to focus on four categories of absolute contraindications: "Arteriosclerosis, arterial circulation disorders", "Diabetes mellitus" (DM), "Tumor and cancer" (TC), "Neurologic diseases, neuronal disorders, epilepsy". Based on scientific studies, quality criteria, safety aspects and benefit/risk assessment of the category, DM and TC were moved to the relative contraindication catalogue, while arteriosclerosis/arterial circulation disorders and neurologic diseases/neuronal disorders/epilepsy were still considered as absolute contraindications. While missing evidence suggests maintaining the status of neurologic diseases/neuronal disorders as an absolute contraindication, the risk/benefit-ratio does not support the application of WB-EMS in people with arteriosclerosis/arterial circulation diseases. Despite these very cautious modifications, countries with less restrictive structures for non-medical WB-EMS should consider our approach critically before implementing the present revisions. Considering further the largely increased amount of WB-EMS trials we advice regular updates of the present contraindication list.

Fatigue as a key factor for testing knee stability with single leg drop landing for injury prevention and return to play tests

Objectives

Fatigue can decrease knee stability and increase the injury risk. However, fatigue is rarely being applied throughout movement analysis. The aim of this study was to investigate if the knee stability throughout SLDLs differ between cyclic and acyclic sports, before and after fatigue in general, and between the dominant and non-dominant leg of soccer players.

Methods

A total of 43 active male (n = 34) and female (n = 9) athletes (age: 26.5 ± 7.2) participated in this study with a pre-post-design. Subjects performed a single leg drop landing (SLDL) from a plyobox. For each leg, the two-dimensional frontal plane projection angle (FPPA) was analyzed. After pretesting the shuttle run test was performed until exhaustion, before repeating the measurements.

Results

ANOVA with repeated measures was applied and identified no significance difference for the FPPA between cyclic and acyclic sports (F = 0.98, p = 0.33), a significant difference before and after fatigue (F = 12.49, p = 0.002) and no significant difference between the dominant and non dominant leg of soccer players (F = 4.35, p = 0.26).

Discussion

Fatigue seems to be able to have a significant influence on knee stability in the frontal axis. Therefore, fatigue should be included in motion analysis for injury prevention and return to play tests because during this physical state most injuries happen.

AB0680 Psychological impact of autologous stem cell transplantation in systemic sclerosis patients and influence of support and coping strategies

Background

In severe cases of systemic sclerosis (SSc), autologous hematopoietic stem cell transplantation (aHSCT) is superior compared to cyclophosphamide with respect to effect on skin and lung manifestations, survival and quality of life. Nevertheless, major physical and psychological impacts have been found in a first qualitative study by Spierings et al. (2020) 1.

Objectives

Assessment of subjectively experienced physical and psychological impacts of aHSCT and exploration of potential interrelations of those impacts.

Methods

A SSc sample was assessed retrospectively after aHSCT in a two-step-approach. In the first step, 6 questionnaires were used: Global physical and mental health (SF-36 and Scleroderma Health Assessment Questionnaire = SHAQ), body image (Adapted Satisfaction with Appearance Scale = ASWAP), coping strategies (Freiburger Fragebogen zur Krankheitsverarbeitung = FKV-15), resilience (Resilienzskala = RS-11), and control beliefs (Fragebogen zur Erfassung von Kontrollüberzeugung zu Krankheit und Gesundheit = KKG). In the second step, semi-structured interviews based on Spierings et al. (2020) 1 were conducted and analysed via mixed methods qualitative content analysis following Mayring (2014).

Results

19 patients (12 female, 7 male, mean age 53.47 years (SD = 9.50)) completed all questionnaires and interviews in a mean time of 6.56 years after aHSCT (SD = 3.90, range 1-12 years). A strong correlation was found between perceived physical impairment (SHAQ) and body image dissatisfaction (ASWAP) (Pearson’s r = .63, p < .001). There was also a strong negative correlation between body image dissatisfaction (ASWAP) and the physical component of SF-36 (pcSF-36; r = -.59, p = .004) and a smaller correlation for the mental component of SF-36 (mcSF-36: r = -.38, p = .054). Depressive coping was negatively associated with SF-36 (pcSF-3: r = -.605, p = .003; mcSF-36: r = -.808, p < .001) (see Figure 1), whereas resilience was associated with a positive impact (pcSF-36: r = .622, p = .002; mcSF-36 r = .595, p = .004). In the qualitative content analysis of the interviews, all patients reported symptom improvements (mainly skin), which were associated with their coping strategies (depressive coping with fewer improvements, active coping with more improvements). Describing their emotional state during aHSCT, 7 patients verbalized “despair”, 6 “loss of control”, 5 “emotional instability”, 4 ”distress due to distance from home”, 4 “loneliness”, 3 “listlessness”, 2 “concern for feelings of relatives”, and 2 “depersonalisation”. As valuable professional emotional support during aHSCT, 6 patients named nurses and 8 named physicians, while the crucial role of daily ward rounds of the specialised transplant team rather than the primary care team was emphasised. The additional support by a psychology team was not deemed necessary by 7 patients, while 4 patients would have wished such a support. 7 patients rated their physical and mental recovery after aHSCT as satisfying, 4 as better than expected, 4 as disappointing, and 3 as causing impatience.

Figure 1.

Correlation of SF-36 (physical and mental component) and FVK-15 (Depressive Coping Score) by Pearson’s Correlation Coefficient

Conclusion

A transient negative impact of aHSCT on mental wellbeing of the majority of SSc patients is evident, but can be relieved by professional teams highly specialised in this particular treatment option.

References

[1]Julia Spierings, et al. From “being at war” to “getting back on your feet”: A qualitative study on experiences of patients with systemic sclerosis treated with hematopoietic stem cell transplantation. Journal of Scleroderma and Related Disorders, vol. 5, 3: pp. 202-209.

Disclosure of Interests

None declared

POS0809 CHARACTERIZATION OF RELAPSES IN PATIENTS WITH GIANT CELL ARTERITIS (GCA) PATIENTS- DATA FROM THE REAL-LIFE TREATMENT AND SAFETY (REATS)-GCA COHORT

Background

Giant cell arteritis (GCA) has the tendency to relapse once treatment is tapered or stopped. Such relapses represent a potential threat to GCA patients as they can lead to severe symptoms and organ damage.

Objectives

To assess the frequency and type of relapses in patients with GCA

Methods

The Real-Life Treatment and Safety (REATS)-GCA cohort has been established by extracting the data on clinical presentation, inflammatory markers, imaging, comorbidities, treatments and serious adverse events of GCA patients from 6 specialized centres in Germany. We undertook descriptive and survival analyses (Kaplan-Meier), and compared baseline characteristics of participants with vs. without relapse. Ethical approval for the cohort was obtained.

Results

We included 395 patients with a mean age of 71 years, including 264 (66.8 %) females and 129 (32.7%) males. Diagnosis of GCA was supported by temporal artery ultrasound in 37%, 18F-FDG-PET/CT in 29%, temporal artery biopsy in 14% of patients and by MRI or clinically in the remaining patients. 31% of patients presented with an isolated cranial manifestation and 18% with isolated extracranial manifestations. Most common presenting symptoms were headache (57%), fatigue (55%), weight loss (42%) and polymyalgia (38%) (Table 1). The most common comorbidities at the time of study inclusion were arterial hypertension (68%), followed by osteoporosis (26%). Within a median total follow-up duration of 22.2 (11.7-40.6) months, 97 of the 395 patients relapsed including 15 patients who relapsed more than once. The median (IQR) time to first relapse was 12.5 (7.1-21.8) months. Median relapse-free survival was 7.8 years with a relapse risk of 12% (CI, 9 to 15%) at 1 year and 38% (CI, 30 to 45%) at 5 years (Figure 1). Most common symptoms at relapse were headache (35%), polymyalgia (23%), fatigue (19%) and night sweats (12%) (Table 1). Three patients relapsed with sudden loss of vision. Among the 114 relapses observed, 94 (83%) occurred under prednisolone treatment with a median dose of 7.0 mg/day (IQR 4.0-12.5). 26 (23%) occurred under methotrexate and 14 (12%) under tocilizumab treatment. Comparing the baseline characteristics that were documented in this study, we did not find a statistically significant difference in relapsing versus non-relapsing GCA patients.

Table 1.Symptom at disease onsetN=395 (%)Symptom at relapseN=97 (%)Headache216 (54.7)Headache35 (30.7)Fatigue208 (52.7)Polymyalgia (PMR)23 (20.2)Weight loss159 (40.3)Fatigue19 (16.7)Polymyalgia (PMR)144 (36.5)Vision impairment13 (11.4)Night sweats140 (35.4)Night sweats12 (10.5)Headache in the temple area125 (31.6)Headache in the temple area12 (10.5)Jaw pain121 (30.6)Jaw pain11 (9.6)Vision impairment118 (29.9)Morning stiffness7 (6.1)Morning stiffness89 (22.5)Weight loss7 (6.1)Fever80 (20.3)Claudication upper limb6 (5.3)Swelling temporal arteries77 (19.5)Arthralgia6 (5.3)Vision loss57 (14.4)Claudication lower limb5 (4.4)Scalp tenderness38 (9.6)Vision loss3 (2.6)Claudication upper limb38 (9.6)Arthritis3 (2.6)Claudication lower limb34 (8.6)Scalp tenderness2 (1.8)Arthralgia28 (7.1)Fever2 (1.8)Arthritis3 (0.8)Swelling temporal arteries2 (1.8)Figure 1.

Conclusion

About one fourth of GCA patients relapsed and the overwhelming majority of relapses occurred before patients were able to stop glucocorticoids. The leading symptoms at relapse are headache and fatigue, while loss of vision is rare (0.76%). Baseline characteristics seem to be poorly informative about the risk of relapse, therefore regular monitoring of GCA patients is necessary.

Acknowledgements

This research was financially supported by Roche Pharma Ag and Chugai Pharma Europe Ltd.

Disclosure of Interests

Verena Schönau Speakers bureau: Novartis, Janssen, Grant/research support from: Roche, Chugai, Giulia Corte: None declared, Sebastian Ott: None declared, Koray Tascilar: None declared, Fabian Hartmann: None declared, Bernhard Manger: None declared, Bernhard Hellmich: None declared, Alexander Pfeil: None declared, Peter Oelzner: None declared, Wolfgang A. Schmidt: None declared, Andreas Krause: None declared, Marc Schmalzing: None declared, Matthias Fröhlich: None declared, Michael Gernert: None declared, Nils Venhoff: None declared, Jörg Henes: None declared, Jürgen Rech Speakers bureau: Abbvie, Biogen, BMS, Chugai, GSK, Lilly, MSD; Novartis, Roche, Sanofi, Sobi, UCB,, Consultant of: Biogen, BMS, Chugai, GSK, Lilly, MSD, Novartis, Roche, Sanofi, Sobi, UCB, Grant/research support from: Sobi, Novartis, Georg Schett: None declared

Rationale and design of the CRAFT (Continuous ReAssessment with Flexible ExTension in Rare Malignancies) multicenter phase II trial

BACKGROUND

Approvals of cancer therapeutics are primarily disease entity specific. Current molecular diagnostic approaches frequently identify actionable alterations in rare cancers or rare subtypes of common cancers for which the corresponding treatments are not approved and unavailable within clinical trials due to entity-related eligibility criteria. Access may be negotiated with health insurances. However, approval rates vary, and critical information required for a scientific evaluation of treatment-associated risks and benefits is not systematically collected. Thus clinical trials with optimized patient selection and comprehensive molecular characterization are essential for translating experimental treatments into standard care.

PATIENTS AND METHODS

Continuous ReAssessment with Flexible ExTension in Rare Malignancies (CRAFT) is an open-label phase II trial for adults with pretreated, locally advanced, or metastatic solid tumors. Based on the evaluation by a molecular tumor board, patients are assigned to combinations of six molecularly targeted agents and a programmed death-ligand 1 (PD-L1) antagonist within seven study arms focusing on (i) BRAF V600 mutations; (ii) ERBB2 amplification and/or overexpression, activating ERBB2 mutations; (iii) ALK rearrangements, activating ALK mutations; (iv and v) activating PIK3CA and AKT mutations, other aberrations predicting increased PI3K-AKT pathway activity; (vi) aberrations predicting increased RAF-MEK-ERK pathway activity; (vii) high tumor mutational burden and other alterations predicting sensitivity to PD-L1 inhibition. The primary endpoint is the disease control rate (DCR) at week 16; secondary and exploratory endpoints include the progression-free survival ratio, overall survival, and patient-reported outcomes. Using Simon's optimal two-stage design, 14 patients are accrued for each study arm. If three or fewer patients achieve disease control, the study arm is stopped. Otherwise, 11 additional patients are accrued. If the DCR exceeds 7 of 25 patients, the null hypothesis is rejected for the respective study arm.

CONCLUSIONS

CRAFT was activated in October 2021 and will recruit at 10 centers in Germany.

TRIAL REGISTRATION NUMBERS

EudraCT: 2019-003192-18; ClinicalTrials.gov: NCT04551521.

Cutaneous epithelioid hemangiomas show somatic mutations in the MAPK pathway

BACKGROUND

Epithelioid hemangioma (EH) arising from the skin is a benign vascular tumor with marked inflammatory cell infiltration, which exhibits a high tendency to persist and frequently recurs after resection. So far, the underlying pathogenesis is largely elusive.

OBJECTIVES

To identify genetic alterations by next-generation-sequencing and/or droplet digital PCR (ddPCR) in cutaneous EH.

METHODS

DNA and RNA from an EH lesion of an index patient were subjected to whole genome and RNA sequencing. Multiplex PCR-based panel sequencing of genomic DNA isolated from archival formalin-fixed paraffin-embedded (FFPE) tissue of 18 cutaneous EH patients was performed. ddPCR was used to confirm mutations.

RESULTS

We identified somatic mutations in genes of the MAPK pathway (MAP2K1 and KRAS) in cutaneous EH biopsies. By ddPCR we could confirm the recurrent presence of activating, low-frequency mutations affecting MAP2K1. In total, 9 out of 18 analyzed patients showed activating MAPK pathway mutations, which were mutually exclusive. Comparative analysis of tissue areas enriched for lymphatic infiltrate or aberrant endothelial cells, respectively, revealed an association of these mutations with the presence of endothelial cells.

CONCLUSIONS

Taken together, our data suggest that EH shows somatic mutations in genes of the MAPK pathway which might contribute to the formation of this benign tumor.

An antibiofilm coating of 5-aryl-2-aminoimidazole covalently attached to a titanium surface

Biofilms, especially those formed by Staphylococcus aureus, play a key role in the development of orthopedic implant infections. Eradication of these infections is challenging due to the elevated tolerance of biofilm cells against antimicrobial agents. In this study, we developed an antibiofilm coating consisting of 5-(4-bromophenyl)-N-cyclopentyl-1-octyl-1H-imidazol-2-amine, designated as LC0024, covalently bound to a titanium implant surface (LC0024-Ti). We showed in vitro that the LC0024-Ti surface reduces biofilm formation of S. aureus in a specific manner without reducing the planktonic cells above the biofilm, as evaluated by plate counting and fluorescence microscopy. The advantage of compounds that only inhibit biofilm formation without affecting the viability of the planktonic cells, is that reduced development of bacterial resistance is expected. To determine the antibiofilm activity of LC0024-Ti surfaces in vivo, a biomaterial-associated murine infection model was used. The results indicated a significant reduction in S. aureus biofilm formation (up to 96%) on the LC0024-Ti substrates compared to pristine titanium controls. Additionally, we found that the LC0024-Ti substrates did not affect the attachment and proliferation of human cells involved in osseointegration and bone repair. In summary, our results emphasize the clinical potential of covalent coatings of LC0024 on titanium implant surfaces to reduce the risk of orthopedic implant infections. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 1908-1919, 2019.

Determination of ventricular volumes in coronary artery disease

Aim: Comparison of two gated SPECT analysis tools – gated SPECT quantification (GSQ) and emory cardiac toolbox (ECT) – in patients with coronary artery disease (CAD) and severely impaired left ventricular function (preoperative: EF <35% by cardiac catheter). Patients, methods: A total of 56 gatedSPECT examinations (oneday hybrid-protocol with 201Tl-chloride for rest and 99mTcsestamibi for stress applied during low-dose dobutamine stress MR-examination; temporal resolution; 8 phases per cardiac cycle) were performed in 36 patients (31 preoperatively, 25 postoperatively) and compared with MRI in 48 cases. Left ventricular end-diastolic (LV-EDV) and end-systolic (LV-ESV) volumes as well as the left ventricular ejection fraction (LV-EF) were calculated. Results: The total volumetric assessment by both analysis algorithms (n = 56) showed good intraclass correlation coefficients preoperatively (n=31), but even better postoperatively (n=25). The mean reconstruction time was approximately 3 minutes (±2 SD) for GSQ and 15 minutes (±5 SD) for ECT. In comparison to MRI the results of both analysis tools also correlated well, but the agreement decreased in the presence of scared tissue. The mean LV-EF (MRI) preoperatively was 30.4%, in 6/36 patients above the values calculated from cardiac catheter, postoperatively 34.6%. Conclusion: Both gated SPECT analysis tools showed reliable volumetric assessments in high-risk patients with CAD and severely reduced LV-EF in comparison to MRI, with advantages for GSQ in terms of postprocessing time. However, for the calculation of LV-EF a markedly lower concordance with MR-results was observed for both methods depending on the presence of myocardial scars.

Is there a sex-shift in prevalence of allergic rhinitis and comorbid asthma from childhood to adulthood? A meta-analysis

Background

Allergic rhinitis and asthma as single entities affect more boys than girls in childhood but more females in adulthood. However, it is unclear if this prevalence sex-shift also occurs in allergic rhinitis and concurrent asthma. Thus, our aim was to compare sex-specific differences in the prevalence of coexisting allergic rhinitis and asthma in childhood, adolescence and adulthood.

Methods

Post-hoc analysis of systematic review with meta-analysis concerning sex-specific prevalence of allergic rhinitis. Using random-effects meta-analysis, we assessed male–female ratios for coexisting allergic rhinitis and asthma in children (0–10 years), adolescents (11–17) and adults (> 17). Electronic searches were performed using MEDLINE and EMBASE for the time period 2000–2014. We included population-based observational studies, reporting coexisting allergic rhinitis and asthma as outcome stratified by sex. We excluded non-original or non-population-based studies, studies with only male or female participants or selective patient collectives.

Results

From a total of 6539 citations, 10 studies with a total of 93,483 participants met the inclusion criteria. The male–female ratios (95% CI) for coexisting allergic rhinitis and asthma were 1.65 (1.52; 1.78) in children (N = 6 studies), 0.61 (0.51; 0.72) in adolescents (N = 2) and 1.03 (0.79; 1.35) in adults (N = 2). Male–female ratios for allergic rhinitis only were 1.25 (1.19; 1.32, N = 5) in children, 0.80 (0.71; 0.89, N = 2) in adolescents and 0.98 (0.74; 1.30, N = 2) in adults, respectively.

Conclusions

The prevalence of coexisting allergic rhinitis and asthma shows a clear male predominance in childhood and seems to switch to a female predominance in adolescents. This switch was less pronounced for allergic rhinitis only.

Electronic supplementary material

The online version of this article (10.1186/s13601-017-0176-5) contains supplementary material, which is available to authorized users.

Volume replacement during trauma resuscitation: a brief synopsis of current guidelines and recommendations

INTRODUCTION

Intravascular volume and fluid replacement are still cornerstones to correct fluid deficits during early trauma resuscitation, but optimum strategies remain under debate.

METHODS

A synopsis of best current knowledge with reference to the following guidelines and recommendations is presented: (1) The European Guideline on Management of Major Bleeding and Coagulopathy following Trauma (fourth edition), (2) S3 Guideline on Treatment of Patients with Severe and Multiple Injuries [English Version of the German Guideline S3 Leitlinie Polytrauma/Schwerverletzten-Behandlung/AWMF Register-Nr. 012/019 sponsored by the German Society for Trauma Surgery/Deutsche Gesellschaft für Unfallchirurgie (DGU)], and (3) S3 Guideline Intravascular Volume Treatment in the Adult [AWMF Register-Nr 001/020 sponsored by the German Society for Anesthesiology and Intensive Medicine/Deutsche Gesellschaft für Anästhesiologie und Intensivmedizin (DGAI)].

RESULTS AND CONCLUSIONS

Volume replacement at a reduced level in severely injured and bleeding trauma patients is advocated (permissive hypotension) until the bleeding is controlled. ATLS principles with Hb, BE, and/or lactate can assess perfusion, estimate/monitor the extent of bleeding/shock, and guide therapy. Isotonic crystalloid solutions are first-line and specific recommendations apply for patients with TBI.

Antibacterial activity of a new broad-spectrum antibiotic covalently bound to titanium surfaces

Biofilm-associated infections, particularly those caused by Staphylococcus aureus, are a major cause of implant failure. Covalent coupling of broad-spectrum antimicrobials to implants is a promising approach to reduce the risk of infections. In this study, we developed titanium substrates on which the recently discovered antibacterial agent SPI031, a N-alkylated 3, 6-dihalogenocarbazol 1-(sec-butylamino)-3-(3,6-dichloro-9H-carbazol-9-yl)propan-2-ol, was covalently linked (SPI031-Ti). We found that SPI031-Ti substrates prevent biofilm formation of S. aureus and Pseudomonas aeruginosa in vitro, as quantified by plate counting and fluorescence microscopy. To test the effectiveness of SPI031-Ti substrates in vivo, we used an adapted in vivo biomaterial-associated infection model in mice in which SPI031-Ti substrates were implanted subcutaneously and subsequently inoculated with S. aureus. Using this model, we found a significant reduction in biofilm formation (up to 98%) on SPI031-Ti substrates compared to control substrates. Finally, we demonstrated that the functionalization of the titanium surfaces with SPI031 did not influence the adhesion and proliferation of human cells important for osseointegration and bone repair. In conclusion, these data demonstrate the clinical potential of SPI031 to be used as an antibacterial coating for implants, thereby reducing the incidence of implant-associated infections. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:2191-2198, 2016.

Adipose-Derived Stem Cells Respond to Increased Osmolarities

Cell therapies present a feasible option for the treatment of degenerated cartilaginous and intervertebral disc (IVD) tissues. Microenvironments of these tissues are specific and often differ from the microenvironment of cells that, could be potentially used for therapy, e.g. human adipose-derived stem cells (hASC). To ensure safe and efficient implantation of hASC, it is important to evaluate how microenvironmental conditions at the site of implantation affect the implanted cells. This study has demonstrated that cartilaginous tissue-specific osmolarities ranging from 400-600 mOsm/L affected hASC in a dose- and time-dependent fashion in comparison to 300 mOsm/L. Increased osmolarities resulted in transient (nuclear DNA and actin reorganisation) and non-transient, long-term morphological changes (vesicle formation, increase in cell area, and culture morphology), as well as reduced proliferation in monolayer cultures. Increased osmolarities diminished acid proteoglycan production and compactness of chondrogenically induced pellet cultures, indicating decreased chondrogenic potential. Viability of hASC was strongly dependent on the type of culture, with hASC in monolayer culture being more tolerant to increased osmolarity compared to hASC in suspension, alginate-agarose hydrogel, and pellet cultures, thus emphasizing the importance of choosing relevant in vitro conditions according to the specifics of clinical application.

In vitro effects of different sources of fibrinogen supplementation on clot initiation and stability in a model of dilutional coagulopathy

OBJECTIVES

To analyse which fibrinogen source may improve coagulation using an in vitro 33% dilutional coagulopathy model.

BACKGROUND

Uncritical volume resuscitation in the context of trauma haemorrhage contributes to the iatrogenic arm of the acute trauma-induced coagulopathy through dilution and depletion of coagulation factors, with fibrinogen reaching critical levels first.

MATERIALS AND METHODS

By using an experimental model of 33% dilutional coagulopathy, we have analysed which fibrinogen source may exert superior effects on improving haemocoagulative capacities and correcting depleted fibrinogen levels. As fibrinogen sources, we supplemented (i) fresh frozen plasma (FFP), (ii) fibrinogen concentrate low-dose (Fib_low ) and (iii) fibrinogen concentrate high-dose (Fib_high ), the latter both in the presence and absence of additional FXIII.

RESULTS

The dilution was associated with decreased haemoglobin and haematocrit levels. Fibrinogen supplementation with fibrinogen-containing formulations led to increased fibrinogen levels (FFP: 172·2 ± 17·4 mg dL^-1 ; Fib_low : 211·5 ± 20·61 mg dL^-1 ; Fib_high : 255·8 ± 21·4 mg dL^-1 ) than in a diluted-only sample (155·5 ± 19·7 mg dL^-1 ). Extrinsically activated assay with tissue factor (EXTEM) clot formation times, α-angles and maximum clot firmness significantly improved in the groups of Fib_low + FXIII (79 ± 12·2 s; 74·3 ± 2·4°; 62 ± 2·3 mm), Fib_high (70·8 ± 10·6 s; 76·2 ± 2·7°; 64·3 ± 2·3 mm) and Fib_high + FXIII (69·8 ± 11·5 s; 77·5 ± 2·7°; 64·33 ± 2·5 mm) compared with the dilution groups (104·2 ± 19 s; 69·7 ± 2·9°; 56·5 ± 3·1 mm). In contrast, rotational thromboelastometric trace (ROTEM) measures of samples supplemented with FFP largely remained unchanged.

CONCLUSION

Fibrinogen concentrates corrected and improved haemodilution-induced changes in blood clotting in vitro. High-dose fibrinogen supplementation was associated with correction and improvement in clot dynamics and stability.

[Early viscoelasticity-based coagulation therapy for severely injured bleeding patients: Report of the consensus group on the consensus conference 2014 for formulation of S2k guidelines]

Although there is increasing interest in the use of a viscoelastic test procedure (ROTEM/TEG) for diagnostics and therapy guidance of severely injured and bleeding patients, currently no uniformly accepted guidelines exist for how this technology should be integrated into clinical treatment. In September 2014 an international multidisciplinary group of opinion leaders in the field of trauma-induced coagulopathy and other disciplines involved in the treatment of severely injured patients were assembled for a 2-day consensus conference in Philadelphia (USA). This panel included trauma/accident surgeons, general/abdominal surgeons, vascular surgeons, emergency/intensive care surgeons, hematologists, transfusion specialists, anesthesiologists, laboratory physicians, pathobiologists/pathophysiologists and the lay public. A total of nine questions regarding the impact of viscoelastic testing in the early treatment of trauma patients were developed prior to the conference by a panel consensus. Early use was defined as baseline viscoelastic test result thresholds obtained within the first minutes of hospital arrival, when conventional laboratory results are not yet available. The available data for each question were then reviewed in person using standardized presentations by the expert panel. A consensus summary document was then developed and reviewed by the panel in an open forum. Finally, a 2-round Delphi poll was administered to the panel of experts regarding viscoelastic thresholds for triggering the initiation of specific treatments including fibrinogen (concentrates), platelet concentrates, blood plasma products and prothrombin complex concentrates (PCC). This report summarizes the findings and recommendations of this consensus conference, which correspond to a S2k guideline according to the system of the Association of the Scientific Medical Societies in Germany (AWMF) and taking formal consensus findings including Delphi methods into consideration.

Inter- and intraobserver reliability of the Rockwood classification in acute acromioclavicular joint dislocations

PURPOSE

The reliability of the Rockwood classification, the gold standard for acute acromioclavicular (AC) joint separations, has not yet been tested. The purpose of this study was to investigate the reliability of visual and measured AC joint lesion grades according to the Rockwood classification.

METHODS

Four investigators (two shoulder specialists and two second-year residents) examined radiographs (bilateral panoramic stress and axial views) in 58 patients and graded the injury according to the Rockwood classification using the following sequence: (1) visual classification of the AC joint lesion, (2) digital measurement of the coracoclavicular distance (CCD) and the horizontal dislocation (HD) with Osirix Dicom Viewer (Pixmeo, Switzerland), (3) classification of the AC joint lesion according to the measurements and (4) repetition of (1) and (2) after repeated anonymization by an independent physician. Visual and measured Rockwood grades as well as the CCD and HD of every patient were documented, and a CC index was calculated (CCD injured/CCD healthy). All records were then used to evaluate intra- and interobserver reliability.

RESULTS

The disagreement between visual and measured diagnosis ranged from 6.9 to 27.6 %. Interobserver reliability for visual diagnosis was good (0.72-0.74) and excellent (0.85-0.93) for measured Rockwood grades. Intraobserver reliability was good to excellent (0.67-0.93) for visual diagnosis and excellent for measured diagnosis (0.90-0.97). The correlations between measurements of the axial view varied from 0.68 to 0.98 (good to excellent) for interobserver reliability and from 0.90 to 0.97 (excellent) for intraobserver reliability.

CONCLUSION

Bilateral panoramic stress and axial radiographs are reliable examinations for grading AC joint injuries according to Rockwood's classification. Clinicians of all experience levels can precisely classify AC joint lesions according to the Rockwood classification. We recommend to grade acute ACG lesions by performing a digital measurement instead of a sole visual diagnosis because of the higher intra- and interobserver reliability.

LEVEL OF EVIDENCE

Case series, Level IV.

[Left ventricular projectile migration after an accidental close-range gunshot wound]

We report the case of a 24-year-old female after sustaining a shotgun wound in the left upper extremity and chest. Initial emergency diagnostics revealed numerous shotgun pellets scattered throughout the left-side soft tissue, chest and upper lung lobe with one pellet having migrated into the left ventricle of the heart.Due to the devastating injury pattern, gunshot wounds are interdisciplinarily challenging and should include extended initial diagnostics, such as contrast agent CT. The potential toxicity of elevated lead blood levels have to be taken into further account.

3-Dimensional porous nanocomposite scaffolds based on cellulose nanofibers for cartilage tissue engineering: tailoring of porosity and mechanical performance

Fully bio-based 3D porous scaffold based on cellulose nanofibers with potential use in cartilage tissue engineering was developed.

Covalent immobilization of antimicrobial agents on titanium prevents Staphylococcus aureus and Candida albicans colonization and biofilm formation

OBJECTIVES

Biofilm-associated implant infections represent a serious public health problem. Covalent immobilization of antimicrobial agents on titanium (Ti), thereby inhibiting biofilm formation of microbial pathogens, is a solution to this problem.

METHODS

Vancomycin (VAN) and caspofungin (CAS) were covalently bound on Ti substrates using an improved processing technique adapted to large-scale coating of implants. Resistance of the VAN-coated Ti (VAN-Ti) and CAS-coated Ti (CAS-Ti) substrates against in vitro biofilm formation of the bacterium Staphylococcus aureus and the fungal pathogen Candida albicans was determined by plate counting and visualized by confocal laser scanning microscopy. The efficacy of the coated Ti substrates was also tested in vivo using an adapted biomaterial-associated murine infection model in which control-Ti, VAN-Ti or CAS-Ti substrates were implanted subcutaneously and subsequently challenged with the respective pathogens. The osseointegration potential of VAN-Ti and CAS-Ti was examined in vitro using human bone marrow-derived stromal cells, and for VAN-Ti also in a rat osseointegration model.

RESULTS

In vitro biofilm formation of S. aureus and C. albicans on VAN-Ti and CAS-Ti substrates, respectively, was significantly reduced compared with biofilm formation on control-Ti. In vivo, we observed over 99.9% reduction in biofilm formation of S. aureus on VAN-Ti substrates and 89% reduction in biofilm formation of C. albicans on CAS-Ti substrates, compared with control-Ti substrates. The coated substrates supported osseointegration in vitro and in vivo.

CONCLUSIONS

These data demonstrate the clinical potential of covalently bound VAN and CAS on Ti to reduce microbial biofilm formation without jeopardizing osseointegration.

Patterns of early resuscitation associated with mortality after penetrating injuries

BACKGROUND

Penetrating injuries are rare in European populations so their management represents a particular challenge. The aim was to assess early therapeutic aspects that are associated with favourable outcomes in patients with penetrating trauma.

METHODS

Patients with penetrating injuries documented from 2009 to 2013 in the TraumaRegister DGU® were analysed. Patients with a primary admission and an Injury Severity Score (ISS) of at least 9 were included. The Revised Injury Severity Classification (RISC) II score was used for mortality prediction, and a standardized mortality ratio (SMR) calculated per hospital. Hospitals with favourable outcome (SMR below 1) were compared with those with poor outcome (SMR 1 or more).

RESULTS

A total of 50 centres had favourable outcome (1242 patients; observed mortality rate 15.7 per cent) and 34 centres had poor outcome (918 patients; observed mortality rate 24.4 per cent). Predicted mortality rates according to RISC-II were 20.4 and 20.5 per cent respectively. Mean(s.d.) ISS values were 22(14) versus 21(14) (P = 0.121). Patients in the favourable outcome group had a significantly shorter time before admission to hospital and a lower intubation rate. They received smaller quantities of intravenous fluids on admission to the emergency room, but larger amounts of fresh frozen plasma, and were more likely to receive haemostatic agents. A higher proportion of patients in the favourable outcome group were treated in a level I trauma centre. Independent risk factors for hospital death following penetrating trauma identified by multivariable analysis included gunshot injury mechanism and treatment in non-level I centres.

CONCLUSION

Among penetrating traumas, gunshot injuries pose an independent risk of death. Treatment of penetrating trauma in a level I trauma centre was significantly and independently associated with lower hospital mortality.

Identification and characterization of an anti-pseudomonal dichlorocarbazol derivative displaying anti-biofilm activity

Pseudomonas aeruginosa strains resistant towards all currently available antibiotics are increasingly encountered, raising the need for new anti-pseudomonal drugs. We therefore conducted a medium-throughput screen of a small-molecule collection resulting in the identification of the N-alkylated 3,6-dihalogenocarbazol 1-(sec-butylamino)-3-(3,6-dichloro-9H-carbazol-9-yl)propan-2-ol (MIC = 18.5 μg mL⁻¹). This compound, compound 1, is bacteriostatic towards a broad spectrum of Gram-positive and Gram-negative pathogens, including P. aeruginosa. Importantly, 1 also eradicates mature biofilms of P. aeruginosa. 1 displays no cytotoxicity against various human cell types, pointing to its potential for further development as a novel antibacterial drug.

Improving tactile sensation in laparoscopic surgery by overcoming size restrictions

Hepatic tumors appear as stiff inclusions within the surrounding soft, healthy tissue. In open surgery they are searched for by manual palpation with the gloved fingertip. However, to exploit the benefits of MIS it is mandatory to implement a substitution for the human sense of touch. Therefore, a tactile instrument has been developed with the aim of enlarging the sensing area at the tool tip once it enters the abdominal cavity through the trocar. The provision of a large sensitive surface enables the detection of nearly all sizes of tumors and decreases the time needed for the performance of this task. A prototype was manufactured by laser sintering in PA serving as a carrier for an existing flexible silicone sensor. Automated as well as manual subject palpation tests have shown that a prototypical instrument with a laterally opening lid would be a suitable device for tumor detection in laparoscopic liver surgery.

Covalent Binding of Heparin to Functionalized PET Materials for Improved Haemocompatibility

The hemocompatibility of vascular grafts made from poly(ethylene terephthalate) (PET) is insufficient due to the rapid adhesion and activation of blood platelets that occur upon incubation with whole blood. PET polymer was treated with NH_x radicals created by passing ammonia through gaseous plasma formed by a microwave discharge, which allowed for functionalization with amino groups. X-ray photoelectron spectroscopy characterization using derivatization with 4-chlorobenzaldehyde indicated that approximately 4% of the –NH₂ groups were associated with the PET surface after treatment with the gaseous radicals. The functionalized polymers were coated with an ultra-thin layer of heparin and incubated with fresh blood. The free-hemoglobin technique, which is based on the haemolysis of erythrocytes, indicated improved hemocompatibility, which was confirmed by imaging the samples using confocal optical microscopy. A significant decrease in number of adhered platelets was observed on such samples. Proliferation of both human umbilical vein endothelial cells and human microvascular endothelial cells was enhanced on treated polymers, especially after a few hours of cell seeding. Thus, the technique represents a promising substitute for wet-chemical modification of PET materials prior to coating with heparin.

Experimental analysis of the mechanical behavior of the viscoelastic porcine pancreas and preliminary case study on the human pancreas

The aim of this article is to study the mechanical properties of the pancreas. Up to now, the mechanical properties of the pancreas are not sufficiently characterized. The possibility of intraoperative mechanical testing of pathological pancreata will allow the classification of pancreatic diseases in the future. The application of mechanical parameters instead of the intraoperative frozen section analysis shortens waiting times in the operating room. This study proves the general applicability of shear rheology for the determination of the mechanical properties of pancreas and the assessment of graft quality for transplantation. Porcine and human pancreas samples were examined ex vivo and a nonlinear viscoelastic behavior was observed. Pancreas was found to be more viscous than liver but both abdominal organs showed a similar flow behavior. The shear deformation dependence of healthy human pancreas was similar to porcine pancreas. An increase in the post-mortem time led to an increase in the complex modulus for a post-mortem time up to 8.5 days. Histological investigations showed that an increased amount of collagen coincides with the stiffening of the pancreatic tissue.

Infrastructure and clinical practice for the detection and management of trauma-associated haemorrhage and coagulopathy

PURPOSE

Early detection and management of post-traumatic haemorrhage and coagulopathy have been associated with improved outcomes, but local infrastructures, logistics and clinical strategies may differ.

METHODS

To assess local differences in infrastructure, logistics and clinical management of trauma-associated haemorrhage and coagulopathy, we have conducted a web-based survey amongst the delegates to the 15th European Congress of Trauma and Emergency Surgery (ECTES) and the 2nd World Trauma (WT) Congress held in Frankfurt, Germany, 25-27 May 2014.

RESULTS

446/1,540 delegates completed the questionnaire yielding a response rate of 29%. The majority specified to work as consultants/senior physicians (47.3%) in general (36.1%) or trauma/orthopaedic surgery (44.5%) of level I (70%) or level II (19%) trauma centres. Clinical assessment (>80%) and standard coagulation assays (74.6%) are the most frequently used strategies for early detection and monitoring of bleeding trauma patients with coagulopathy. Only 30% of the respondents declared to use extended coagulation assays to better characterise the bleeding and coagulopathy prompted by more individualised treatment concepts. Most trauma centres (69%) have implemented local protocols based on international and national guidelines using conventional blood products, e.g. packed red blood cell concentrates (93.3%), fresh frozen plasma concentrates (93.3%) and platelet concentrates (83%), and antifibrinolytics (100%). 89% considered the continuous intake of anticoagulants including "new oral anticoagulants" and platelet inhibitors as an increasing threat to bleeding trauma patients.

CONCLUSIONS

This study confirms differences in infrastructure, logistics and clinical practice for the detection and management of trauma-haemorrhage and trauma-associated coagulopathy amongst international centres. Ongoing work will focus on geographical differences.

Evaluation of the toxicity of 5-aryl-2-aminoimidazole-based biofilm inhibitors against eukaryotic cell lines, bone cells and the nematode Caenorhabditis elegans

Previously, we have synthesized several series of compounds based on the 5-aryl-2-aminoimidazole scaffold, which showed a preventive activity against microbial biofilms. We here studied the cytotoxicity of the most active compounds of each series. First, the cytostatic activity was investigated against a number of tumor cell lines (L1210, CEM and HeLa). A subset of monosubstituted 5-aryl-2-aminoimidazoles showed a moderate safety window, with therapeutic indices (TIs) ranging between 3 and 20. Whereas introduction of a (cyclo-)alkyl chain at the N1-position strongly reduced the TI, introduction of a (cyclo-)alkyl chain or a triazole moiety at the 2N-position increased the TI up to 370. Since a promising application of preventive anti-biofilm agents is their use in anti-biofilm coatings for orthopedic implants, their effects on cell viability and functional behavior of human osteoblasts and bone marrow derived mesenchymal stem cells were tested. The 2N-substituted 5-aryl-2-aminoimidazoles consistently showed the lowest toxicity and allowed survival of the bone cells for up to 4 weeks. Moreover they did not negatively affect the osteogenic differentiation potential of the bone cells. Finally, we examined the effect of the compounds on the survival of Caenorhabditis elegans, which confirmed the higher safety window of 2N-substituted 5-aryl-2-aminoimidazoles.

S-palmitoylation represents a novel mechanism regulating the mitochondrial targeting of BAX and initiation of apoptosis

The intrinsic pathway of apoptotic cell death is mainly mediated by the BCL-2-associated X (BAX) protein through permeabilization of the mitochondrial outer membrane (MOM) and the concomitant release of cytochrome c into the cytosol. In healthy, non-apoptotic cells, BAX is predominantly localized in the cytosol and exhibits a dynamic shuttle cycle between the cytosol and the mitochondria. Thus, the initial association with mitochondria represents a critical regulatory step enabling BAX to insert into MOMs, promoting the release of cytochrome c and ultimately resulting in apoptosis. However, the molecular mode of how BAX associates with MOMs and whether a cellular regulatory mechanism governs this process is poorly understood. Here we show that in both primary tissues and cultured cells, the association with MOMs and the proapoptotic action of BAX is controlled by its S-palmitoylation at Cys-126. A lack of BAX palmitoylation reduced BAX mitochondrial translocation, BAX oligomerization, caspase activity and apoptosis. Furthermore, ectopic expression of specific palmitoyl transferases in cultured healthy cells increases BAX S-palmitoylation and accelerates apoptosis, whereas malignant tumor cells show reduced BAX S-palmitoylation consistent with their reduced BAX-mediated proapoptotic activity. Our findings suggest that S-palmitoylation of BAX at Cys126 is a key regulatory process of BAX-mediated apoptosis.

Assessment of cardiac inflammation and remodeling during the development of streptozotocin-induced diabetic cardiomyopathy in vivo: a time course analysis

In this study, we examined cardiac inflammation, fibrosis and left ventricular (LV) function during the development of streptozotocin (STZ)-induced diabetic cardiomyopathy using an animal model of diabetes mellitus (DM). Diabetes was induced in 22 Sprague‑Dawley rats by an intraperitoneal single injection of STZ (70 mg/kg). Non-diabetic animals served as the controls (n=6). LV function was documented using the conductance catheter technique 2 and 6 weeks after the induction of diabetes. Cardiac tissue was analyzed for cardiac immune cell infiltration, oxidative stress and remodeling in rats with STZ-induced diabetes at 2 different time points by immunohistochemistry. Cardiac function was significantly impaired in the diabetic animals. After 2 weeks, the induction of diabetes resulted in impaired cardiac function indexed by a decrease in systolic and diastolic LV function. This impairment of LV performance continued for up to 6 weeks after the STZ injection. This was associated with an increase in cardiac CD3+ and CD8a+ immune cell invasion and fibrosis, indexed by an increase in collagen content (p<0.05). Furthermore, oxidative stress response and matrix remodeling were increased after 2 weeks and this continued for up to 6 weeks after the induction of diabetes. In conclusion, cardiac dysfunction is associated with cardiac inflammation and adverse remodeling in experimental diabetic cardiomyopathy. Our results suggest that the model of STZ-induced diabetic cardiomyopathy is a robust model for investigating cardiac immune response and LV remodeling processes under diabetic conditions.

[Two-years' follow-up after lumbar disc surgery.]

INTRODUCTION

Outcome studies of lumbar disc surgery document a success rate ranging between 49% and 90%, according to the evaluation criteria used. The aim of the present study was to investigate the prognostic value of pain history and of sociodemographic, psychodiagnostic and medical factors for the long-term outcome after lumbar disc surgery.

METHODS

Between selection for and performance of operations for herniated lumbar disc, 100 patients took part in standardized interviews about their clinical and social history. During the same session they answered one questionnaire on depression and one on coping strategies in response to pain. Two years after the operation, 83 patients answered the standardized follow-up questionnaires.

RESULTS

During the follow-up period, 7 (8.4%) patients had further back surgery, and 20% of the patients reported severe back pain on the follow up. With multivariate discriminant analysis, correct prediction of at most moderate back pain or severe back pain 2 years after the operation had been possible in 94.3% of the patients. The important predictors were found to be: duration of subjectively reduced working capability, pain at other locations, consideration or application for disability pension, depression, and severe acute pain. Risk factors for further back surgery were pain at other locations, guest for social support in response to pain, absence of muscle palsy and of Laségue's sign.

CONCLUSION

Anamnestic information on the pain history and psychological factors have prognostic value for the outcome after lumbar disc surgery. If there is no absolute medical indication for disc surgery, we suggest reconsidering the treatment planned for patients with the risk factors specified.

Optimizing the medium perfusion rate in bone tissue engineering bioreactors

There is a critical need to increase the size of bone grafts that can be cultured in vitro for use in regenerative medicine. Perfusion bioreactors have been used to improve the nutrient and gas transfer capabilities and reduce the size limitations inherent to static culture, as well as to modulate cellular responses by hydrodynamic shear. Our aim was to understand the effects of medium flow velocity on cellular phenotype and the formation of bone-like tissues in three-dimensional engineered constructs. We utilized custom-designed perfusion bioreactors to culture bone constructs for 5 weeks using a wide range of superficial flow velocities (80, 400, 800, 1,200, and 1,800 µm/s), corresponding to estimated initial shear stresses ranging from 0.6 to 20 mPa. Increasing the flow velocity significantly affected cell morphology, cell-cell interactions, matrix production and composition, and the expression of osteogenic genes. Within the range studied, the flow velocities ranging from 400 to 800 µm/s yielded the best overall osteogenic responses. Using mathematical models, we determined that even at the lowest flow velocity (80 µm/s) the oxygen provided was sufficient to maintain viability of the cells within the construct. Yet it was clear that this flow velocity did not adequately support the development of bone-like tissue. The complexity of the cellular responses found at different flow velocities underscores the need to use a range of evaluation parameters to determine the quality of engineered bone.

Bone grafts engineered from human adipose-derived stem cells in perfusion bioreactor culture

We report engineering of half-centimeter-sized bone constructs created in vitro using human adipose-derived stem cells (hASCs), decellularized bone scaffolds, and perfusion bioreactors. The hASCs are easily accessible, can be used in an autologous fashion, are rapidly expanded in culture, and are capable of osteogenic differentiation. hASCs from four donors were characterized for their osteogenic capacity, and one representative cell population was used for tissue engineering experiments. Culture-expanded hASCs were seeded on fully decellularized native bone scaffolds (4 mm diameter x 4 mm thick), providing the necessary structural and mechanical environment for osteogenic differentiation, and cultured in bioreactors with medium perfusion. The interstitial flow velocity was set to a level necessary to maintain cell viability and function throughout the construct volume (400 microm/s), via enhanced mass transport. After 5 weeks of cultivation, the addition of osteogenic supplements (dexamethasone, sodium-beta-glycerophosphate, and ascorbic acid-2-phosphate) to culture medium significantly increased the construct cellularity and the amounts of bone matrix components (collagen, bone sialoprotein, and bone osteopontin). Medium perfusion markedly improved the distribution of cells and bone matrix in engineered constructs. In summary, a combination of hASCs, decellularized bone scaffold, perfusion culture, and osteogenic supplements resulted in the formation of compact and viable bone tissue constructs.

Tissue engineered bone grafts: biological requirements, tissue culture and clinical relevance

The tremendous need for bone tissue in numerous clinical situations and the limited availability of suitable bone grafts are driving the development of tissue engineering approaches to bone repair. In order to engineer viable bone grafts, one needs to understand the mechanisms of native bone development and fracture healing, as these processes should ideally guide the selection of optimal conditions for tissue culture and implantation. Engineered bone grafts have been shown to have capacity for osteogenesis, osteoconduction, osteoinduction and osteointegration - functional connection between the host bone and the graft. Cells from various anatomical sources in conjunction with scaffolds and osteogenic factors have been shown to form bone tissue in vitro. The use of bioreactor systems to culture cells on scaffolds before implantation further improved the quality of the resulting bone grafts. Animal studies confirmed the capability of engineered grafts to form bone and integrate with the host tissues. However, the vascularization of bone remains one of the hurdles that need to be overcome if clinically sized, fully viable bone grafts are to be engineered and implanted. We discuss here the biological guidelines for tissue engineering of bone, the bioreactor cultivation of human mesenchymal stem cells on three-dimensional scaffolds, and the need for vascularization and functional integration of bone grafts following implantation.

Hypoxia and stem cell-based engineering of mesenchymal tissues

Stem cells have the ability for prolonged self-renewal and differentiation into mature cells of various lineages, which makes them important cell sources for tissue engineering applications. Their remarkable ability to replenish and differentiate in vivo is regulated by both intrinsic and extrinsic cellular mechanisms. The anatomical location where the stem cells reside, known as the "stem cell niche or microenvironment," provides signals conducive to the maintenance of definitive stem cell properties. Physiological condition including oxygen tension is an important component of the stem cell microenvironment and has been shown to play a role in regulating both embryonic and adult stem cells. This review focuses on oxygen as a signaling molecule and the way it regulates the stem cells' development into mesenchymal tissues in vitro. The physiological relevance of low oxygen tension as an environmental parameter that uniquely benefits stem cells' expansion and maintenance is described along with recent findings on the regulatory effects of oxygen on embryonic stem cells and adult mesenchymal stem cells. The relevance to tissue engineering is discussed in the context of the need to specifically regulate the oxygen content in the cellular microenvironment in order to optimize in vitro tissue development.

Evaluation of rabbit auricular chondrocyte isolation and growth parameters in cell culture

Auricular cartilage is an attractive potential source of cells for many tissue engineering applications. However, there are several requirements that have to be fulfilled in order to develop a suitable tissue engineered implant. Animal experiments serve as important tools for validating novel concepts of cartilage regeneration; therefore rabbit auricular chondrocytes were studied. Various parameters including isolation procedures, passage number, rate of proliferation and gene expression profile for major extracellular matrix components were evaluated in order to assess the potential use of elastic chondrocytes for tissue engineering. Chondrocytes were isolated from rabbit ear cartilage and grown in monolayer cultures over four passages. Yields of harvested cells and proliferation were analysed from the digestion step to the fourth passage, and changes in phenotype were monitored. The proliferation capacity of cell cultures decreased during cultivation and was accompanied by enlargement of cells, this phenomenon being especially evident in the third and fourth passages. The expression of cartilage specific genes for collagen type II, aggrecan and cartilage non-specific collagen type I was determined. The mRNA levels for all three genes were obviously lower in the primo culture than immediately after isolation. During subsequent cultivation the expression of collagen type II decreased further, while there were only slight changes in expression of aggrecan and collagen type I. This study provides a valuable basis for testing of different tissue engineering applications in rabbit model, where auricular chondrocytes are considered as cell source.

[Determination of ventricular volumes in coronary artery disease: comparison of two gated SPECT analysis tools with MRI]

AIM

Comparison of two gated SPECT analysis tools -- gated SPECT quantification (GSQ) and emory cardiac toolbox (ECT) -- in patients with coronary artery disease (CAD) and severely impaired left ventricular function (preoperative: EF <35% by cardiac catheter).

PATIENTS, METHODS

A total of 56 gated SPECT examinations (one-day hybrid-protocol with (201)Tl-chloride for rest and (99m)Tc-sestamibi for stress applied during low-dose dobutamine stress MR-examination; temporal resolution; 8 phases per cardiac cycle) were performed in 36 patients (31 preoperatively, 25 postoperatively) and compared with MRI in 48 cases. Left ventricular end-diastolic (LV-EDV) and end-systolic (LV-ESV) volumes as well as the left ventricular ejection fraction (LV-EF) were calculated.

RESULTS

The total volumetric assessment by both analysis algorithms (n = 56) showed good intraclass correlation coefficients preoperatively (n = 31), but even better postoperatively (n = 25). The mean reconstruction time was approximately 3 minutes ( +/- 2 SD) for GSQ and 15 minutes ( +/- 5 SD) for ECT. In comparison to MRI the results of both analysis tools also correlated well, but the agreement decreased in the presence of scared tissue. The mean LV-EF (MRI) preoperatively was 30.4%, in 6/36 patients above the values calculated from cardiac catheter, postoperatively 34.6%.

CONCLUSION

Both gated SPECT analysis tools showed reliable volumetric assessments in high-risk patients with CAD and severely reduced LV-EF in comparison to MRI, with advantages for GSQ in terms of postprocessing time. However, for the calculation of LV-EF a markedly lower concordance with MR-results was observed for both methods depending on the presence of myocardial scars.

Myocardial viability assessment in patients with highly impaired left ventricular function: comparison of delayed enhancement, dobutamine stress MRI, end-diastolic wall thickness, and TI201-SPECT with functional recovery after revascularization

This study compared different magnetic resonance imaging (MRI) methods with Tl(201) single photon emission computerized tomography (SPECT) and the "gold standard" for viability assessment, functional recovery after coronary artery bypass grafting (CABG). Twenty patients (64+/-7.3 years) with severely impaired left ventricular function (ejection fraction [EF] 28.6+/-8.7%) underwent MRI and SPECT before and 6 months after CABG. Wall-motion abnormalities were assessed by stress cine MRI using low-dose dobutamine. A segment with a nonreversible defect in Tl(201)-SPECT and a delayed enhancement (DE) in an area >50% of the entire segment, as well as an end-diastolic wall thickness <6 mm, was defined as nonviable. The mean postoperative EF (n=20) improved slightly from 28.6+/-8.7% to 32.2+/-12.4% (not significant). Using the Tl(201)-SPECT as the reference method, end-diastolic wall thickness, MRI-DE, and stress MRI showed high sensitivity of 94%, 93%, and 84%, respectively, but low specificities. Using the recovery of contractile function 6 months after CABG as the gold standard, MRI-DE showed an even higher sensitivity of 99%, end-diastolic wall thickness 96%, stress MRI 88%, and Tl(201)-SPECT 86%. MRI-DE showed advantages compared with the widely used Tl(201)-SPECT and all other MRI methods for predicting myocardial recovery after CABG.