Cells in Slow Motion: Apparent Undercooling Increases Glassy Behavior at Physiological Temperatures

Solvent conditions are unexpectedly sufficient to drastically and reversibly slow down cells. In vitro on the molecular level, protein-solvent interactions drastically change in the presence of heavy water (D₂ O) and its stronger hydrogen bonds. Adding D₂ O to the cell medium of living cells increases the molecular intracellular viscosity. While cell morphology and phenotype remain unchanged, cellular dynamics transform into slow motion in a changeable manner. This is exemplified in the slowdown of cell proliferation and migration, which is caused by a reversible gelation of the cytoplasm. In analogy to the time-temperature superposition principle, where temperature is replaced by D₂ O, an increase in viscosity slows down the effective time. Actin networks, crucial structures in the cytoplasm, switch from a power-law-like viscoelastic to a more rubber-like elastic behavior. The resulting intracellular resistance and dissipation impair cell movement. Since cells are highly adaptive non-equilibrium systems, they usually respond irreversibly from a thermodynamic perspective. D₂ O induced changes, however, are fully reversible and their effects are independent of signaling as well as expression. The stronger hydrogen bonds lead to glass-like, drawn-out intramolecular dynamics, which may facilitate longer storage times of biological matter, for instance, during transport of organ transplants.

POS0041 THE GASOTRANSMITTER HYDROGEN SULFIDE (H2S) IS PROTECTIVE AGAINST CALCIFIC TENDINOPATHY (CT)

Background:

Pathological (or heterotopic) calcification is the deposition of calcium-containing crystals in soft tissues that normally do not calcify. The deposition of these crystals in tendons such as the rotator cuff and the Achilles tendon is known as calcific tendinopathy (CT). CT is a painful condition, which increases tendon rupture rate and leads to disability.

Objectives:

To understand what inhibits calcification, in order to provide new strategies to treat a condition for which existing therapies are ineffective.

Methods:

We investigated the role of the gasotransmitter hydrogen sulfide (H2S), and in particular of the H2S-producing enzyme cystathionine γ-lyase (CSE) in CT. In vitro, we induced calcification in tenocytes from WT and CSE KO mice or we treated WT tenocytes with different H2S donors. In vivo, calcification was assessed in a surgery-induced murine model of CT (tenotomy of the Achilles tendon) and in a spontaneous model of CT (aging). Samples obtained from patients with rotator cuff or Achilles tendon CT were also analyzed. To investigate the underlying mechanisms of the CSE-H2S effect, we focused on the bone morphogenic proteins (BMPs) pathway. We additionally explored if altered extracellular matrix (ECM) organization, due to lysyl oxidase (LOX) activity and aberrant collagen-crosslinks, could also be involved in CT. In this context, we studied if H2S could affect LOX expression and activity.

Results:

In vitro, tenocyte calcification was inhibited by exogenous H2S-donors, while it was exacerbated in CSE KO tenocytes. The protective role of CSE-H2S was confirmed in vivo. In aged mice, microtomography analysis revealed exacerbated Achilles tendon calcification in CSE KO mice compared to WT. In the surgery-induced model of CT, an inverse correlation between calcification and CSE expression in operated Achilles tendon was seen over time. Similarly, inversed correlation between calcification and CSE expression was found in human CT samples.

Reduced calcification in tenocytes exposed to H2S was accompanied by decreased expression of genes coding for BMP2, BMP4 and decreased activation of the BMP signaling pathway (pSMAD1/5/8). On the contrary, BMPs expression and BMPs-pathway activation were exacerbated in CSE KO tenocytes compared to WT tenocytes.

We next investigated whether ECM disorganization could play a role in CT. Tenocytes cultured in calcification media and treated with the pan-inhibitor of lysyl oxidases (LOX, LOXL1-4) β-aminopropionitrile (BAPN) showed decreased calcification. This pointed to a potential beneficial role of LOX inhibition, therefore decreased collagen-crosslinks, in CT. By analysis of LOXs gene expression in WT and CSE KO tenocytes cultured in calcifying condition, we found much higher expression (4-fold) of LOX, LOL2 and LOXL4 in CSE KO tenocytes. Moreover, H2S-donors inhibited LOX activity. Altogether, these results suggest that decreased H2S could lead to aberrant LOX expression and activity, excessive collagen cross-links in the ECM, and ultimately calcification. Further experiments are ongoing to prove these hypotheses.

Conclusion:

We suggest targeting H2S production by CSE, or supplying an H2S-donor, is of therapeutic relevance to pathological calcification in the context of CT and can modify its disease course.

The anti-mineralizing effect of H2S in tendons could be due to both inhibition of the BMPs pathway and suppression of abnormal LOXs activity.

Disclosure of Interests:

None declared.

An altered heparan sulfate structure in the articular cartilage protects against osteoarthritis

OBJECTIVE

Osteoarthritis (OA) is a progressive degenerative disease of the articular cartilage caused by an unbalanced activity of proteases, cytokines and other secreted proteins. Since heparan sulfate (HS) determines the activity of many extracellular factors, we investigated its role in OA progression.

METHODS

To analyze the role of the HS level, OA was induced by anterior cruciate ligament transection (ACLT) in transgenic mice carrying a loss-of-function allele of Ext1 in clones of chondrocytes (Col2-rtTA-Cre;Ext1e2fl/e2fl). To study the impact of the HS sulfation pattern, OA was surgically induced in mice with a heterozygous (Ndst1+/-) or chondrocyte-specific (Col2-Cre;Ndst1fl/fl) loss-of-function allele of the sulfotransferase Ndst1. OA progression was evaluated using the OARSI scoring system. To investigate expression and activity of cartilage degrading proteases, femoral head explants of Ndst1+/- mutants were analyzed by qRT-PCR, Western Blot and gelatin zymography.

RESULTS

All investigated mouse strains showed reduced OA scores (Col2-rtTA-Cre;Ext1e2fl/e2fl: 0.83; 95% HDI 0.72-0.96; Ndst1+/-: 0.83, 95% HDI 0.74-0.9; Col2-Cre;Ndst1fl/fl: 0.87, 95% HDI 0.76-1). Using cartilage explant cultures of Ndst1 animals, we detected higher amounts of aggrecan degradation products in wildtype samples (NITEGE 4.24-fold, 95% HDI 1.05-18.55; VDIPEN 1.54-fold, 95% HDI 1.54-2.34). Accordingly, gelatin zymography revealed lower Mmp2 activity in mutant samples upon RA-treatment (0.77-fold, 95% HDI: 0.60-0.96). As expression of major proteases and their inhibitors was not altered, HS seems to regulate cartilage degeneration by affecting protease activity.

CONCLUSION

A decreased HS content or a reduced sulfation level protect against OA progression by regulating protease activity rather than expression.

THU0435 CALCIUM PYROPHOSPHATE DIHYDRATE (CPPD) CRYSTALS BUT NOT BASIC CALCIUM PHOSPHATE (BCP) CRYSTALS INDUCE SYNDECAN-4 EXPRESSION IN CARTILAGE

Background:

Chondrocalcinosis is a painful rheumatic condition caused by the deposition of calcium pyrophosphate dihydrate crystals (CPPD) in joint tissues, and especially in cartilage. It is known that CPPD crystals cause inflammation and degenerative changes in joint, but the underlying mechanisms remain poorly understood. In particular, nothing is known about how these crystals regulates transmembrane heparan sulphate proteoglycans (HSPGs). Our attention focused on one family of HSPGs called syndecans as they have important roles both as adhesion molecules, by mediating chondrocyte-extracellular matrix interactions, and as modulators of intracellular signaling triggered by cytokines and growth factors.

Objectives:

The aim of this study was to evaluate how CPPD crystals modulates syndecan expression in chondrocytes and in cartilage, and how this modulation can be ultimately linked to cartilage damage during chondrocylcinosis.

Methods:

Murine chondrocitic ATDC5 cells were stimulated with 0,1 ng/ml CPPD crystals or with 0,1 ng/ml basic-calcium phosphate crystals (BCP), a family of calcium-containing crystals found in other rheumatic conditions such as osteoarthritis (OA). Cytotoxicity was evaluated by lactate dehydrogenase (LDH) release in the supernatant at 30 minutes, and 3, 6, 24 hours after stimulation. At the same time-points, mRNA expression levels of syndecans (Synd-1, -2, -3, -4) and of matrix-degrading enzymes (Mmp-3, -9, -13; Adamts-4, -5) was analysed by qRT-PCR. Finally, Syndecan-4 protein expression was studied by immunohistochemistry (IHC) in cartilage samples of patients with chondrocalcinosis and in samples of patients with severe OA without chondrocalcinosis as control.

Results:

LDH assay revealed no increased cytotoxicity by CPPD or BCP at any time-point. qRT-PCR indicated that CPPD crystals but not BCP crystals induced Synd-2 and -3 upregulation at 30 minutes after stimulation and Synd-4 upregulation at 3 hours, while no modulation of syndecans was seen at later time-points. CPPD also induced Adamts-4 expression at 3 hours after stimulation, and Mmp-9 expression at 3 and 6 hours. The expression of the other matrix-degrading enzymes was not affected. Human chondrocalcinosis cartilage exhibited enhanced Synd-4 expression compared to severe OA cartilage containing BCP calcification. Interestingly, Synd-4 expression was observed in the extracellular matrix but not on cell membrane, suggesting that maybe Synd-4 undergoes shedding (Figure 1).

Figure 1.

Representative Synd-4 IHC in control patients (Ctrl, severe OA) and chondrocalcinosis patients (CPPD). Note increased Synd-4 expression in extracellular matrix of CPPD patients compared to Ctrl ones.

Conclusion:

BCP and CPPD crystals seem to trigger differential effects in terms of modulation of syndecans in chondrocitic cells. CPPD crystals induce Synd-4 and Adamts-4 and Mmp-9 which are not induced by BCP crystals. It remains to be clarified whether the two events are interlinked. In particular, further studies are required to investigate if Adamts-4 and Mmp-9 are involved in Synd-4 shedding or if vice versa Synd-4 regulates Adamts-4 and Mmp-9 activation and downstream cartilage breakdown in chondrocalcinosis.

Disclosure of Interests: :

Sonia Nasi: None declared, Jessica Bertrand Grant/research support from: Pfizer, Speakers bureau: Pfizer, Miriam Bollmann: None declared, Richard Stange: None declared, Thomas Pap: None declared

Half-body MRI volumetry of abdominal adipose tissue in patients with obesity

Background

The purpose of this study was to determine to what extent the whole volumes of abdominal subcutaneous (ASAT) and visceral adipose tissue (VAT) of patients with obesity can be predicted by using data of one body half only. Such a workaround has already been reported for dual-energy x-ray absorption (DEXA) scans and becomes feasible whenever the field of view of an imaging technique is not large enough.

Methods

Full-body abdominal MRI data of 26 patients from an obesity treatment center (13 females and 13 males, BMI range 30.8–41.2 kg/m², 32.6–61.5 years old) were used as reference (REF). MRI was performed with IRB approval on a clinical 1.5 T MRI (Achieva dStream, Philips Healthcare, Best, Netherlands). Segmentation of adipose tissue was performed with a custom-made Matlab software tool. Statistical measures of agreement were the coefficient of determination R² of a linear fit.

Results

Mean ASAT_REF was 12,976 (7812–24,161) cm³ and mean VAT_REF was 4068 (1137–7518) cm³. Mean half-body volumes relative to the whole-body values were 50.8% (48.2–53.7%) for ASAT_L and 49.2% (46.3–51.8%) for ASAT_R. Corresponding volume fractions were 56.4% (51.4–65.9%) for VAT_L and 43.6% (34.1–48.6%) for VAT_R. Correlations of ASAT_REF with ASAT_L as well as with ASAT_R were both excellent (R² > 0.99, p < 0.01). Corresponding correlations of VAT_REF were marginally lower (R² = 0.98 for VAT_L, p < 0.01, and R² = 0.97 for VAT_R, p < 0.01).

Conclusions

In conclusion, abdominal fat volumes can be reliably assessed by half-body MRI data, in particular the subcutaneous fat compartment.

[Stimulation of fracture healing by growth factors and cell-based technologies]

Bone has the special capability to completely regenerate after trauma and to re-establish its original geometry and biomechanical stability corresponding to the pretrauma conditions. Nevertheless, in daily clinical practice impaired fracture healing and nonunions are regular complications as a result of inadequate mechanical stability and/or insufficient biological processes around the fracture region. Since the beginning of the millennium, intensive research on the physiological processes in bone healing as well as the production and clinical administration of growth factors have enabled the possibility to improve the local biological processes during fracture healing by osteoinduction. Although the initial clinical results, particularly of bone morphogenetic proteins, in fracture healing were promising, growth factors did not become established for unrestricted use in the clinical application. Currently, additional growth factors are being investigated with respect to the potential supportive and osteoinductive characteristics for enhancement of fracture healing and possible clinical applications. Furthermore, the development of cell-based technologies is another promising approach to positively stimulate fracture healing. In addition to the gold standard of autologous bone grafting, harvesting of mesenchymal stroma cells by aspiration has gained in importance in recent years. Allogeneic bone cell transplantation procedures and in particular gene therapy are promising new strategies for the treatment of disorders of fracture healing. This review gives an overview of present and future possibilities for modulation of fracture healing by growth factors and cell-based technologies.

MRI assessment of changes in adipose tissue parameters after bariatric surgery

Bariatric surgery and other therapeutic options for obese patients are often evaluated by the loss of weight, reduction of comorbidities or improved quality of life. However, little is currently known about potential therapy-related changes in the adipose tissue of obese patients. The aim of this study was therefore to quantify fat fraction (FF) and T1 relaxation time by magnetic resonance imaging (MRI) after Roux-en-Y gastric bypass surgery and compare the resulting values with the preoperative ones. Corresponding MRI data were available from 23 patients (16 females and 7 males) that had undergone MRI before (M0) and one month after (M1) bariatric surgery. Patients were 22–59 years old (mean age 44.3 years) and their BMI ranged from 35.7–54.6 kg/m² (mean BMI 44.6 kg/m²) at M0. Total visceral AT volumes (V_VAT-T, in L) were measured by semi-automatic segmentation of axial MRI images acquired between diaphragm and femoral heads. MRI FF and T1 relaxation times were measured in well-defined regions of visceral (VAT) and subcutaneous (SAT) adipose tissue using two custom-made analysis tools. Average BMI values were 45.4 kg/m² at time point M0 and 42.4 kg/m² at M1. Corresponding V_VAT-T values were 5.94 L and 5.33 L. Intraindividual differences in both BMI and V_VAT-T were highly significant (p<0.001). Average relaxation times T1_VAT were 303.7 ms at M0 and 316.9 ms at M1 (p<0.001). Corresponding T1_SAT times were 283.2 ms and 280.7 ms (p = 0.137). Similarly, FF_VAT differences (M0: 85.7%, M1: 83.4%) were significant (p <0.01) whereas FF_SAT differences (M0: 86.1, M1: 85.9%) were not significant (p = 0.517). In conclusion, bariatric surgery is apparently not only related to a significant reduction in common parameters of adipose tissue distribution, here BMI and total visceral fat volume, but also significant changes in T1 relaxation time and fat fraction of visceral adipose tissue. Such quantitative MRI measures may potentially serve as independent biomarkers for longitudinal and cross-sectional measurements in obese patients.

Dicomflex: A novel framework for efficient deployment of image analysis tools in radiological research

Objective

Medical image processing tools in research are often developed from scratch without the use of predefined software structures, which potentially makes them less reliable and difficult to maintain. The objective here was to present and evaluate a novel framework (Dicomflex) for the deployment of tools with a uniform workflow, commonly encountered in medical image analysis.

Materials and methods

The object-oriented code was developed using Matlab. Dicomflex applications follow the common workflow of image-slice selection, user interaction, image processing, result visualization and progression to next slice. The framework consists of three important classes that host functionality, two configuration files and a front end that displays images, graphs and resulting data.

Results

So far, three different research tools have been created under the new framework. In comparison with previous Matlab analysis tools used at our institution, users of Dicomflex tools subjectively considered the learning phase to be shorter and handling to be simpler and more intuitive. They also highlighted the benefit and comfort of the standardized interface and predefined workflow. The framework-inherent handling of software versions was considered highly beneficial for maintenance as well as data and software management at different project stages. The clear separation of framework-related and unrelated code allows for a fast and more direct design of new tools in well-defined steps. The flexibility of the framework translates to a wide range of image processing tasks, such as segmentation, region-of-interest (ROI) analyses or computation of functional parameter maps, but is limited to 2D datasets.

Conclusion

Potential medical applications include the assessment of cardiac performance, detection of cerebrovascular disease or characterization of cancerous lesions. Dicomflex tools share a similar workflow and host the pertinent functions only. This may be relevant for many image processing needs in radiological research, where quick software deployment and reliability of results is essential.

[Safety culture in orthopedics and trauma surgery : Course concept: interpersonal competence by the German Society for Orthopaedics and Trauma (DGOU) and Lufthansa Aviation Training]

Patient safety has become a central and measurable key factor in the routine daily medical practice. The human factor plays a decisive role in safety culture and has moved into focus regarding the reduction of treatment errors and undesired critical incidents. Nonetheless, the systematic training in communication and interpersonal competences has so far only played a minor role. The German Society of Orthopaedics and Trauma (DGOU) in cooperation with the Lufthansa Aviation Training initiated a course system for interpersonal competence. Several studies confirmed the reduction of critical incidents and costs after implementation of a regular and targeted human factor training. The interpersonal competence should be an essential component of specialist training within the framework of a 3‑column model.

[Interpersonal competence in orthopedics and traumatology : Why technical and procedural skills alone are not sufficient]

Patient safety has increasingly gained significance as criterion which clinics and doctors will be measured against in terms of ethics and finances. The "human factor" moved into focus regarding the question of how to reduce treatment errors in clinical daily routine. Nevertheless, systematic mediation of interpersonal competences only plays a minor role in the catalogue of requirements for medical specialization and professional training. This is the case not only in orthopedics and traumatology, but in other medical fields as well. At the insistence of DGOU and in cooperation with Lufthansa Flight Training, a training model was initiated, comparable to training models used in aviation. In aviation, apart from the training of procedural and technical abilities, regular soft skills training has become standard in the training of all Lufthansa staff. Several studies confirm that by improving communication, interaction, and teamwork skills not only a reduction of intolerable incidents is observed, but also a positive economic effect. Interpersonal competences should be firmly anchored in orthopedics and traumatology and thus be implemented as third post in specialist training.

[The Summer School of the German Society for Orthopaedics and Traumatology - A Success Story]

Background: It has been known for several years that orthopaedic and trauma clinics suffer from a shortage of young people, due to the substantial loss in attractiveness. The Youth Forum OU has been addressing this problem for many years, by initiating many projects such as the Summer School to counteract this trend. The purpose of this research is to evaluate the success of Summer Schools since 2009. Methods: The Youth Forum OU performed a survey in December 2014 to answer the research question on the basis of an internet-based poll of the student participants in all Summer Schools between 2009 and 2014. Following data cleansing, 121 students and former students were included in the survey. Results: Seventy-two completed questionnaires were collected and included in the evaluation. The survey included 40 % of Summer School participants, with a mean age of 27.3 years (SD ± 2.95); 50 % were female. Participation in the Summer School helped 50 % of the respondents to decide to start advanced study in orthopaedics and/or traumatology (OU). One third of these Summer School participants had already finished a university degree; 100 % are now residents in orthopaedics and/or traumatology. Regardless of prior plans, 87.2 % of participants are now residents in OU. Thirty-three are still students: 78.8 % have already decided to work in OU. The survey also served to identify the factors positively and negatively associated with OU. Unfavourable factors included the reputation of OU, and the difficulty of reconciling family and work. Favourable factors included surgical work and personal experience during university studies. Discussion: The aim of this study was to evaluate whether the efforts of the Youth Forum OU, the German Society for Orthopaedics and Traumatology (DGOU) and the local hospitals lead to increased interest in OU. The answer to this question is positive. This is particularly true for those students who did not plan to become an orthopaedic or trauma surgeon before participating in a Summer School. In conclusion, the efforts to recruit residents for OU by using Summer Schools were successful. Moreover, this research offers approaches to counteract the loss of attractiveness of OU.

The lensing effect of trapped particles in a dual-beam optical trap

In dual-beam optical traps, two counterpropagating, divergent laser beams emitted from opposing laser fibers trap and manipulate dielectric particles. We investigate the lensing effect that trapped particles have on the beams. Our approach makes use of the intrinsic coupling of a beam to the opposing fiber after having passed the trapped particle. We present measurements of this coupling signal for PDMS particles, as well as a model for its dependence on size and refractive index of the trapped particle. As a more complex sample, the coupling of inhomogeneous biological cells is measured and discussed. We show that the lensing effect is well captured by the simple ray optics approximation. The measurements reveal intricate details, such as the thermal lens effect of the beam propagation in a dual-beam trap. For a particle of known size, the model further allows to infer its refractive index simply from the coupling signal.

[Daily routine in orthopedics and traumatology - results of a nationwide survey of residents]

BACKGROUND

The subject orthopedics and traumatology suffers by a loss of attractiveness which results in a lack of young blood. The aim of this study of the Youth Forum of the German Society of Orthopedics and Traumatology (DGOU) is to register the working conditions of residents in orthopedics.

MATERIAL AND METHODS

In the months September and October 2013 we performed a survey on members of the following German societies: German Society of Orthopedics and Traumatology (DGOU), German Society of Traumatology (DGU) and the German Society of Orthopedics and Orthopedic Surgery (DGOOC), (age < 40). Our questionnaire includes 15 questions.

RESULTS

We achieved 28,9 % (n = 331) answered questionnaires. The mean working time per week is 55 hours. 73 % of all participants do more than 5 emergency services per month. 52 % are more than 3 times on duty for 24 hours. Only 13 % of all residents have well ordered working hours. Normally working time is divided into three parts: one third for bureaucracy, one for operation theatre and the last for other activities (e.g. ward round). 35,6 % do only one surgery per week, 12 % do not perform any surgeries. An annual report is performed only in 45 %. A structured concept of training only exists in 16 % of all hospitals. In addition to clinical work 45 % are involved in scientific projects, mostly in their spare-time. Finally 58 % of all surgeons would still recommend orthopedics and traumatology.

CONCLUSION

In order to maintain orthopedics and traumatology as an attractive it is necessary to implement flexible working time models and to reorganize and improve training-concepts.

[Further training in the faculty of orthopedics and trauma surgery. Outstanding, average or insufficient?]

A well structured and executed and practical residency program is important to secure a sufficient number of well trained orthopedic surgeons in the future. Some of the residents, however, see substantial shortcomings here. Additionally, orthopedic residency programs struggle to be a valid alternative for graduated medical students when comparing them to residency programs in other medical specialities or alternative job options. In improving the current situation program directors as well as residents must play a key role. A rapid improvement of structural shortcomings of German residency programs does not only provide an advantage in recruiting new residents now, but may also help to maintain the high quality in orthopedic health care in the future.

[How many generalists and how many specialists does orthopedics and traumatology need?]

The training in orthopedic and trauma surgery has changed significantly with the introduction of the new residency program. The contents taught have already been reduced in breadth and the current developments in the outpatient and particularly in the clinical landscape also contribute to increasing specialization. This trend favors structures in which comprehensive medical care for the population in Germany in orthopedic and trauma surgery appears to be endangered and in which the future efforts for e.g. polytraumatised patients need to be questioned. The Young Forum of the German Society for Orthopedics and Traumatology actively accompanies a discussion about the necessity and value of generalists to ensure the level of care in Germany in addition to the specialists.

[Treatment of periprosthetic and peri-implant fractures : modern plate osteosynthesis procedures]

Periprosthetic fractures are increasing not only due to the demographic development with high life expectancy, the increase in osteoporosis and increased prosthesis implantation but also due to increased activity of the elderly population. The therapeutic algorithms are manifold but general valid rules for severe fractures are not available. The most commonly occurring periprosthetic fractures are proximal and distal femoral fractures but in the clinical routine fractures of the tibial head, ankle, shoulder, elbow and on the borders to other implants (peri-implant fractures) and complex interprosthetic fractures are being seen increasingly more. It is to be expected that in the mid-term further options, such as cement augmentation of cannulated polyaxial locking screws will extend the portfolio of implants for treatment of periprosthetic fractures. The aim of this review article is to present the new procedures for osteosynthesis of periprosthetic fractures.

Active contractions in single suspended epithelial cells

Investigations of active contractions in tissue cells to date have been focused on cells that exert forces via adhesion sites to substrates or to other cells. In this study we show that also suspended epithelial cells exhibit contractility, revealing that contractions can occur independently of focal adhesions. We employ the Optical Stretcher to measure adhesion-independent mechanical properties of an epithelial cell line transfected with a heat-sensitive cation channel. During stretching the heat transferred to the ion channel causes a pronounced Ca(2+) influx through the plasma membrane that can be blocked by adequate drugs. This way the contractile forces in suspended cells are shown to be partially triggered by Ca(2+) signaling. A phenomenological mathematical model is presented, incorporating a term accounting for the active stress exerted by the cell, which is both necessary and sufficient to describe the observed increase in strain when the Ca(2+) influx is blocked. The median and the shape of the strain distributions depend on the activity of the cells. Hence, it is unlikely that they can be described by a simple Gaussian or log normal distribution, but depend on specific cellular properties such as active contractions. Our results underline the importance of considering activity when measuring cellular mechanical properties even in the absence of measurable contractions. Thus, the presented method to quantify active contractions of suspended cells offers new perspectives for a better understanding of cellular force generation with possible implications for medical diagnosis and therapy.

[Arthroplasty for fractures of the femur near the hip joint]

The incidence of proximal fractures of the femur will increase with the demographic change in the German population. Besides osteosynthesis, which in most cases of femoral neck, pertrochanteric and femoral head fracture is the method of choice, arthroplasty of the hip is likewise an established therapy. Indications are dislocated femoral neck fractures of the elderly. But there are good results for arthroplasty after proximal femoral fractures in younger active patients as well, when the fracture was not recognized or treated immediately. The outcome of hip arthroplasty after fracture is influenced by the elderly and unhealthy patient himself and the difficult planning and operation conditions due to fracture and its morphology. Most important for the best result are an interdisciplinary preparation of the patient and a well-planned surgery. In these cases common complications like thromboembolism, massive intraoperative blood loss and general infections like urinary tract infection can be reduced. For hip arthroplasty after fracture total hip replacement as well as hemiarthroplasty with bipolar prosthesis should be considered. The implant chosen and the implantation technique with or without bone cement has to be determined. Facts like the general state of health, biological age, level of activity and comorbidities should be taken into account appropriately.

Randomised clinical trial: a herbal preparation of myrrh, chamomile and coffee charcoal compared with mesalazine in maintaining remission in ulcerative colitis--a double-blind, double-dummy study

BACKGROUND

The herbal treatment with myrrh, dry extract of chamomile flowers and coffee charcoal has anti-inflammatory and antidiarrhoeal potential and might benefit patients with UC. Aminosalicylates are used as standard treatment for maintaining remission in ulcerative colitis (UC).

AIM

To compare the efficacy of the two treatments in maintaining remission in patients with ulcerative colitis.

METHODS

We performed a randomised, double-blind, double-dummy study over a 12-month period in patients with UC. Primary endpoint was non-inferiority of the herbal preparation as defined by mean Clinical Colitis Activity Index (CAI-Rachmilewitz). Secondary endpoints were relapse rates, safety profile, relapse-free times, endoscopic activity and faecal biomarkers.

RESULTS

A total of 96 patients (51 female) with inactive UC were included. Mean CAI demonstrated no significant difference between the two treatment groups in the intention-to-treat (P = 0.121) or per-protocol (P = 0.251) analysis. Relapse rates in total were 22/49 patients (45%) in the mesalazine treatment group and 25/47 patients (53%) in the herbal treatment group (P = 0.540). Safety profile and tolerability were good and no significant differences were shown in relapse-free time, endoscopy and faecal biomarkers.

CONCLUSIONS

The herbal preparation of myrrh, chamomile extract and coffee charcoal is well tolerated and shows a good safety profile. We found first evidence for a potential efficacy non-inferior to the gold standard therapy mesalazine, which merits further study of its clinical usefulness in maintenance therapy of patients with ulcerative colitis. EudraCT-Number 2007-007928-18.

Willow bark extract STW 33-I in the long-term treatment of outpatients with rheumatic pain mainly osteoarthritis or back pain

STUDY OBJECTIVE

Efficacy and safety of willow bark extract for pain reduction in patients suffering from musculoskeletal disorders (MSD) has been shown in clinical short term trials. Therefore this observational study over 6 months should evaluate patterns of treatments like mono- or combinations therapy, dosage and safety during long-term treatment under pragmatic conditions with the aqueous willow bark extract STW 33-I, (Proaktiv(®); drug-extract-ratio 16-23:1).

PATIENTS AND METHODS

The patients were treated with STW 33-I; comedication with other NSAIDs and opioids was allowed. An extensive case report form including pain questionnaires and patient diary was used for outcome evaluation.

RESULTS

Four hundred and thirty-six patients with rheumatic pain mainly due to osteoarthritis (56.2%) and back pain (59.9%) were included. During the study the mean reductions from baseline value 58.4±22.6-31.8±22.5 after 24 weeks in the pain intensity scale (VAS 0-100mm) were significant even after 3 weeks with a reduction by 26 mm (45.6% of the baseline value) at the end of the study. The relative reductions of the weekly means of the daily patient self-rated scores of the pain (6-point Likert-scales) were between 33% and 44% of the baseline values during the course of the study. We present results of subgroups according their analgetic/antiphlogistic comedication. The distribution and specification of the main adverse events and the ratings of the treatment showed a good tolerability. No relevant drug interactions were reported.

CONCLUSION

These data suggest that STW 33-I can be used as a basic treatment in the long-term therapy of painful musculoskeletal disorders and that it can be combined with NSAIDs and opioids if necessary.

The potential of implant augmentation in the treatment of osteoporotic distal femur fractures: a biomechanical study

PURPOSE

Osteoporotic fractures of the distal femur are an underestimated and increasing problem in trauma and orthopaedic surgery. Therefore, this study investigates the biomechanical potential of implant augmentation in the treatment of these fractures.

METHODS

Twelve osteoporotic surrogate distal femora were randomly assigned to the augmented or non-augmented group. All specimens were fixed using the LCP DF. In the augmented group additionally 1ml Vertecem V+ was injected in each screw hole before screw positioning. The construct represents an AO 33 A3 fracture. Biomechanical testing was performed as sinusoidal axial loading between 50 and 500N with 2Hz for 45,000 cycles, followed by loading between 50 and 750N until failure.

RESULTS

The augmented group showed significant higher axial stiffness (36%). Additionally the displacement after 45,000 cycles was 3.4 times lower for the augmented group (0.68±0.2mm vs. 2.28±0.2mm). Failure occurred after 45,130 cycles (SD 99) in all of the non-augmented specimens and in two specimens of the augmented group after 69,675 cycles (SD 1729). Four of the augmented specimens showed no failure. The failure mode of all specimens in both groups was a medial cut-out.

CONCLUSIONS

This study shows a promising potential of implant augmentation in the treatment of osteoporotic distal femur fractures.

[Compatibility of science and clinical aspects. Between realism and utopia]

The working environment for young residents in orthopedic surgery has changed tremendously over the past 10 years. Due to cumulative clinical requirements and increasing demands on work-life balance research activity has become less attractive. Successful incorporation of research into the career of residents is a challenging project for the future. The young forum of the German Association for Orthopedics and Traumatology (DGOU) provides different approaches to enhance the quality of research and to help young orthopedists and trauma surgeons.

Phase II trial on the effects of Silexan in patients with neurasthenia, post-traumatic stress disorder or somatization disorder

Silexan, a novel lavender oil preparation for oral use, has been authorized in Germany for the treatment of states of restlessness during anxious mood. An open-label, exploratory trial was performed to assess the potential of the medicinal product in the treatment of restlessness caused by anxiety as related to several disorders. Outcome measures included the Symptom Checklist-90-Revised (SCL-90-R), von Zerssen's Depression Scale (D-S), the 36-item Short Form Health Survey Questionnaire (SF-36), and a sleep diary. 50 male and female patients with neurasthenia (ICD-10 F48.0), post-traumatic stress disorder (PSD; F43.1), or somatization disorder (F45.0, F45.1) were included to receive 1 × 80 mg/day Silexan over 6 weeks; 47 could be analyzed for efficacy as full analysis set. At baseline, patients suffered from restlessness (96%), depressed mood (98%), sleep disturbances (92%), or anxiety (72%). Of those, resp. 62%, resp. 57%, resp.51%, resp. 62% showed improvements during treatment (p < 0.001). For all patients, mean D-S score decreased by 32.7% and SCL-90-R Global Severity Index by 36.4% as compared to baseline, (p < 0.001), while the SF-36 Mental Health Score increased by 48.2% (p < 0.001). Waking-up frequency (p = 0.002), Waking-up duration (p < 0.001) and morning tiredness (p = 0.005) were reduced, while efficiency of sleep (p = 0.018) and mood (p = 0.03) improved. Patients suffering from neurasthenia or PSD showed comparable improvements with most outcomes. The results in this trial justify to further investigate Silexan in disorders with accompanying restlessness caused by sub-threshold anxiety. Adverse reactions, predominantly gastrointestinal complaints, were judged as mild or moderate.

Local delivery of growth factors using coated suture material

The optimization of healing processes in a wide range of tissues represents a central point for surgical research. One approach is to stimulate healing processes with growth factors. These substances have a short half-life and therefore it seems useful to administer these substances locally rather than systemically. One possible method of local delivery is to incorporate growth factors into a bioabsorbable poly (D, L-lactide) suspension (PDLLA) and coat suture material. The aim of the present study was to establish a procedure for the local delivery of growth factors using coated suture material. Sutures coated with growth factors were tested in an animal model. Anastomoses of the colon were created in a rat model using monofilament sutures. These were either untreated or coated with PDLLA coating alone or coated with PDLLA incorporating insulin—like growth factor-I (IGF-I). The anastomoses were subjected to biomechanical, histological, and immunohistochemical examination. After 3 days the treated groups showed a significantly greater capacity to withstand biomechanical stress than the control groups. This finding was supported by the results of the histomorphometric. The results of the study indicate that it is possible to deliver bioactive growth factors locally using PDLLA coated suture material. Healing processes can thus be stimulated locally without subjecting the whole organism to potentially damaging high systemic doses.

[Periprosthetic fractures. An interdisciplinary challenge]

Demographic changes and rising numbers of implanted prostheses accompanied by increasing demands on mobility and activities of the elderly will lead to an increasing number of periprosthetic fractures in the future. Poor bone quality, geriatric comorbidities and multiple prostheses result in an increased risk for this type of fracture in the old patient. Management of these patients is challenging and demanding and needs an interdisciplinary approach. The present work describes the different aspects of periprosthetic fractures in the geriatric patient with regard to epidemiology, risk factors, prevention and treatment options.

Calcium imaging in the optical stretcher

The Microfluidic Optical Stretcher (MOS) has previously been shown to be a versatile tool to measure mechanical properties of single suspended cells. In this study we combine optical stretching and fluorescent calcium imaging. A cell line transfected with a heat sensitive cation channel was used as a model system to show the versatility of the setup. The cells were loaded with the Ca(2+) dye Fluo-4 and imaged with confocal laser scanning microscopy while being stretched. During optical stretching heat is transferred to the cell causing a pronounced Ca(2+) influx through the cation channel. The technique opens new perspectives for investigating the role of Ca(2+) in regulating cell mechanical behavior.

Cholesterol reduction using psyllium husks - do gastrointestinal adverse effects limit compliance? Results of a specific observational study

PURPOSE

Despite known cholesterol lowering effects the use of psyllium husk (Plantaginis ovatae testa) in Germany for hypercholesterolemia is limited compared to their use as a laxative. To investigate whether use in hypercholesterolemia is limited due to adverse effects on the gastrointestinal system, a prospective observational study was conducted.

METHODS

Sixty-two outpatients with documented hypercholesterolemia and complaints of constipation were identified from an academic clinical center. Treatment with 3.5g psyllium husk preparation administered three times daily was initiated and patients were monitored at weekly intervals. Gastrointestinal symptoms were quantified using a validated Nepean Dyspepsia Index modified to identify both upper and lower abdominal symptoms. Diaries and study medication records were used to evaluate compliance.

RESULTS

Fifty-four of 62 patients enrolled in the study completed the study protocol with 4 subjects discontinuing due to adverse reactions associated with psyllium husks. Total cholesterol was significantly decreased from 252+/-39mg/dl before treatment to 239+/-37mg/dl after 3 weeks of treatment. Similarly, low density lipoprotein (LDL)-cholesterol decreased from 174+/-34 to 162+/-31mg/dl during the study. Triglycerides and high density lipoprotein (HDL) were unchanged. Gastrointestinal symptoms were rated lower at the end than at the beginning of the study. In week 1 most of the patients reported gastrointestinal symptoms and also gastrointestinal adverse reactions, which however, showed a decrease from week 1 to weeks 2 and 3 in the diaries. Patient response to study medication was positive for patients completing the study.

CONCLUSIONS

Psyllium husk preparations may be a therapeutic option for patients with mild to moderately elevated cholesterol levels. Adverse gastrointestinal symptoms associated with the preparation appear to be transient in some of the patients. Compliance may be optimized with adequate patient counseling.