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Introduction Determining the normal values for acoustic radiation force impulse (ARFI) shear wave elastography of the thoracolumbar fascia (TLF) and define possible factors of influence. Methods We measured the shear wave velocity (SWV) in m/s and the diameter (anterior-posterior) in mm of the TLF bilateral in 267 healthy participants with the Acuson S3000™ (Siemens) using the virtual touch image quantification mode (VTIQ). The parameters were tested for correlations with the anthropometric data of the participants, between different age groups and the genders, as well as information obtained from the history, such as smoking and sporting activities. Results We determined a mean SWV of 3.28 ± 0.55 m/s for the left thoracolumbar fascia and 3.44 ± 0.55 m/s for the right. The diameter on the right was 2.7 ± 0.8 mm. On the left, it was 2.7 ± 0.9 mm. Neither body mass index (BMI) nor gender had a significant effect on either of the measured parameters (p > 0.05). The same goes for regular medication, sporting activity or the consumption of alcohol (p > 0.05). The results concerning the effect of smoking and age were inconclusive as they only had a significant influence to either the right or the left side of the TLF but not on the other side. Conclusions We collected the normal value for ARFI shear wave elastography of the TLF in 267 healthy participants. Furthermore, neither gender, BMI, sports activity nor the consumption of alcohol affected the elasticity or the diameter of the thoracolumbar fascia.

Alveolar echinococcosis (AE) is a rare zoonotic disease caused by the larval stage of Echinococcus multilocularis. Despite its low world-wide prevalence, this disease shows differences in the regional distribution of cases. In the present cohort study, we analyse the distribution of AE according to environmental and geographical factors in Germany. We identified the place of residence of 591 cases of AE from the national database for AE, and georeferenced these localities in the Universal Transverse Mercator coordinate system. Data on elevation, air temperature, precipitation height and land cover were mapped out and correlated with the distribution of cases of disease during the period 1992-2018. Moran's I statistic was used for spatial autocorrelation. Differences in frequency distribution between elevation, air temperature, precipitation height and landscape feature classes were analysed with the Kruskal-Wallis test. With the multiple linear regression analysis, we determined the influences and interactions of geographical and climatic factors on the number of AE cases. The results showed a heterogeneous distribution of AE cases with a higher concentration in southern Germany than in the rest of Germany (I = 0.225517, Z = 35.8182 and p < 0.001). There was a statistically significant difference in frequency distribution between precipitation height, air temperature, elevation and landscape feature classes and AE cases in Germany (p < 0.0001). In regions with higher elevations (505-672 m), moderate average air temperatures (6.0-7.9°C) and higher precipitation rates (701-1000 mm) most AE cases were recorded. It seems, that regions with higher precipitation rates, higher elevations and moderate average air temperatures have a higher infection burden and infection conditions. It is therefore extremely important to generate greater awareness of the disease in these regions, with the aim of recognising potential cases of AE as early as possible and introducing the appropriate therapeutic measures.

Granulocytes are key effector cells of the innate immune system that cause substantial by-stander tissue damage in a broad range of inflammatory disorders. Specific antibodies with the potential to regulate granulocyte survival are present in polyclonal intravenous immunoglobulin (IVIG) preparations and may contribute to the anti-inflammatory effects of high-dose IVIG therapy. Here, we discuss idiosyncratic characteristics of antibodies to FAS and Siglecs contained in IVIG pertaining to granulocyte death regulation and highlight implications for research and clinical practice.

Background Pulmonary metastasectomy is widely accepted for different malignant diseases. The role of mediastinal lymph node (LN) dissection in these procedures is discussed controversially. We evaluated our results of LN removal at the time of pulmonary metastasectomy with respect to the frequency of unexpected LN disease. Methods This was a retrospective analysis of 313 resections performed in 209 patients. Operations were performed in curative intention. Patients with known thoracic LN involvement and those without lymphadenectomy (n = 43) were excluded. Patients were analyzed according the type of LN dissection. Subgroups of different primary cancers were evaluated separately. Results Sublobar resections were performed in 256 procedures with lymphadenectomy, and 14 patients underwent lobectomy. Patients underwent radical lymphadenectomy (n = 158) or LN sampling (n = 112). The overall incidence of unexpected tumor in LN was 17% (radical lymphadenectomy, 15.8%; sampling, 18.8%). Unexpected LN involvement was found in 17 patients (35.5%) with breast cancer, in 120 (9.2%) with colorectal cancer, and in 53 (20.8%) with renal cell carcinoma. The 5-year survival was 30.2% if LN were tumor negative and 25% if positive ( p = 0.19). LN sampling vs radical removal had no significant effect on 5-year survival (23.6% vs 30.9%; p = 0.29). Conclusions Dissection of mediastinal LN in resection of lung metastases will reveal unexpected LN involvement in a relevant proportion of patients, in particular in breast and renal cancer. Routine LN dissection appears necessary and may become important for further therapeutic decisions. On the basis of our data, LN sampling seems to be sufficient.

Zinc is an essential micronutrient that is crucial for many vital cellular functions such as DNA and protein synthesis, metabolism, and intracellular signaling. Therefore, the intracellular zinc concentration is tightly regulated by zinc transporters and zinc-binding proteins. The members of the SCL39 transporter family transport zinc into the cytosol. The SLC39A2 (hZIP2) protein is highly expressed in prostate epithelial cells and was found to be involved in prostate cancer development. Thus far, there is no specific modulator available for the SLC39 transporters. The aim of this study was to develop a screening assay for compound screening targeting hZIP2. Employing the pIRES2-DsRed Express 2 bicistronic vector, we detected human ZIP2 expression at the plasma membrane in transiently transfected HEK293 cells. Using the FLIPR Tetra fluorescence plate reader, we demonstrated that ZIP2 transports Cd(2+) with an apparent K(m) value of 53.96 nM at an extracellular pH of 6.5. The cadmium influx via hZIP2 was inhibited by zinc in a competitive manner. We found that hZIP2 activity can be measured using cadmium in the range of 0.1 to 10 µM with our assay. In summary, for the first time we developed an assay for human ZIP2 that can be adapted to other zinc transporters.

TRPV5 and TRPV6 are two major calcium transport pathways in the human body maintaining calcium homeostasis. TRPV5 is mainly expressed in the distal convoluted and connecting tubule where it is the major, regulated pathway for calcium reabsorption. TRPV6 serves as an important calcium entry pathway in the duodenum and the placenta. Previously, we showed that human TRPV6 (hTRPV6) transports several heavy metals. In this study we tested whether human TRPV5 (hTRPV5) also transports cadmium and zinc, and whether hTRPV5 together with hTRPV6 are involved in cadmium and zinc toxicity. The hTRPV5 mRNA and protein were expressed in HEK293 cells transiently transfected with pTagRFP-C1-hTRPV5. The overexpression of the hTRPV5 protein at the plasma membrane was revealed by cell surface biotinylation and immunofluorescence techniques. We observed that both cadmium and zinc permeate hTRPV5 in ion imaging experiments using Fura-2 or Newport Green DCF. Our results were further confirmed using whole-cell patch clamp technique. Transient overexpression of hTRPV5 or hTRPV6 sensitized cells to cadmium and zinc. Toxicity curves of cadmium and zinc were also shifted in hTRPV6 expressing HEK293 cells clones. Our results suggest that TRPV5 and TRPV6 are crucial gates controlling cadmium and zinc levels in the human body especially under low calcium dietary conditions, when these channels are maximally upregulated.

Spider dragline silk, solely made from protein, outperforms synthetic fibers in terms of toughness and extensibility, which is thought to originate from its refined nano-scale hierarchical structure. The key for understanding the outstanding mechanical performance of dragline silk lies in a detailed description of the underlying molecular structure and dynamics under load conditions. Here, we aim at determining the ingredients for silk's outstanding toughness using multi-scale computational simulations. First, we present large-scale molecular-dynamics simulations of the structure and dynamics of silk protein. We introduce the most comprehensive, to date, spider silk models comprising of hundred 500-residue chains of two spider proteins, namely MaSp1 and MaSp2, using a collapsing-annealing protocol [1]. Our systems are composed of crystalline beta-sheet segments completely embedded in and connected with an amorphous phase. On this basis, we developed a three-dimensional continuum model of dragline silk for finite element analysis. Such model takes into account the plasticity of the beta-sheets, the rate-dependent dynamics of the amorphous phase, and the viscous friction between them [2]. Tensile properties, velocity-dependent effects and hysteresis are in good agreement with experimental data. Intriguingly, the simulations revealed that under load conditions, crystals rearrange into lamellar bands. We could confirm this trend by small-angle neutron scattering of silk fibers under stress, with simulations and experiments showing quantitatively the same shift and intensity in the signal from the periodically forming bands. The increased order results in a more homogenous stress distribution and higher fiber toughness. Our combined atomistic and fiber-level simulations and experiments suggest that the test stress-induced order is a common feature in materials combining crystalline and amorphous phases on the nano-scale.[1] Cruz-Chu, E. R et al. Faraday Discussions (2009) 143, 47-62[2] Sandeep Patil et al. PLOS One (2014) 9, e104832

Objective In aortic valve regurgitation and aortic dilatation, preservation of the aortic valve is possible by means of root remodeling (Yacoub procedure) or valve reimplantation (David procedure). In vivo studies suggest that reimplantation might substantially influence aortic valve-motion characteristics. Evaluation of aortic valve movement in vivo, however, is technically limited and is difficult to standardize. We evaluated the aortic valve-motion pattern echocardiographically in vitro after reimplantation and remodeling. Methods By using aortic roots of house pigs (aortoventricular diameter, 22 mm) a Yacoub procedure (22-mm graft; group Y, n = 5) or a David I procedure (24-mm graft; group D, n = 5) was performed. Roots after supracommissural replacement (22-mm graft; group C, n = 5) served as control valves. In an electrohydraulic, computer-controlled pulse duplicator the valves were tested at flows of 2, 4, 7, and 9 L/min. Echocardiographically assessed parameters were rapid valve-opening velocity, slow valve-closing velocity, rapid valve-closing velocity, rapid valve-opening time, rapid valve-closing time, ejection time, maximum valve opening, slow valve-closing displacement, and maximum flow velocity. Results Mean rapid valve-opening velocity and mean rapid valve-closing velocity at a cardiac output of 2 to 9 L/min were fastest in group D (rapid valve-opening velocity: 69 ± 10 cm/s [group D] vs 39 ± 4 cm/s [group Y] vs 42 ± 4 cm/s [group C], P = .0041; rapid valve-closing velocity: 22 ± 2 cm/s [group D] vs 16 ± 2 cm/s [group Y] vs 17 ± 1 cm/s [group C], P = .0272), and slow valve-closing velocity was slowest in group D (0.2 ± 0.1 cm/s [group D] vs 1.0 ± 0.3 cm/s [group Y] vs 0.6 ± 0.1 cm/s [group C], P = .0063). With increasing cardiac output, the difference in rapid valve-opening velocity between the groups increased, the difference in slow valve-closing velocity remained unchanged, and the difference in rapid valve-closing velocity decreased. Conclusions In this standardized experimental setting remodeling of the aortic valve provides significantly smoother valve movements. This might contribute to preservation of a better valve performance during long-term follow-up.

Background. Pneumonectomy has traditionally been the treatment of choice for central lung tumors. Bronchial sleeve resections are increasingly considered as a reasonable alternative. For tumor involvement of both central airways and pulmonary artery, bronchovascular sleeve resections are possible, but considered to be technically demanding and associated with a higher perioperative risk. In addition, their role as adequate oncologic treatment for lung cancer is unclear. We have compared the early and long-term results of bronchovascular sleeve resection with those of bronchial sleeve resection and pneumonectomy. Methods. We retrospectively analyzed all patients who underwent bronchial sleeve resection (group I, n 104), bronchovascular sleeve resection (group II, n 67), and pneumonectomy (group III, n 63) for central lung cancer in our institution. Results. The groups were comparable regarding demographics and tumor, node, and metastasis (TNM) stage. Early mortality was 1.9% in group I, 1.5% in group II, and 6.3% in group III (p 0.19). The rate of bronchial complications was 0.96% in group I, 0% in group II, and 7.9% in group III (p 0.006). Five-year survival was 46.1% in group I, 42.9% in group II, and 30.4% in group III (p 0.16). Freedom from local recurrence of disease (5 years) was 83.8% in group I, 84.2% in group II, and 88.7% in group III (p 0.56). Conclusions. Bronchovascular sleeve resections are as safe as bronchial sleeve resections for the treatment of central lung cancer. Both procedures have comparable early and long-term results, which are similar to those of pneumonectomy. It appears reasonable to apply bronchovascular sleeve resections more liberally.

Objective: Valve-preserving aortic replacement has evolved into an accepted therapeutic option for aortic ectasia with morphologically intact leaflets. Some patients, however, exhibit additional leaflet prolapse. We compared the results of established valve-preserving techniques with those of the combination of valve-preserving aortic surgery and additional repair of leaflet prolapse. Methods: Between October 1995 and March 2000, 99 patients underwent valve-preserving root replacement by means of root remodeling or valve reimplantation for acute dissection (n = 25), chronic dissection (n = 4), or aneurysm (n = 70). In group A (63 patients) either root remodeling (n = 49) or valve reimplantation (n = 14) was performed with a standard technique. In group B (36 patients) valvepreserving aortic replacement (remodeling, n = 31; reimplantation, n = 5) was combined with repair of leaflet prolapse in the presence of bicuspid (n = 24) or tricuspid (n = 12) valve anatomy. Additional replacement of the aortic arch was required more frequently in group A (group A, n = 43; group B, n = 14; P =.006); otherwise, the groups were comparable. Results: Cardiopulmonary bypass (group A, 133 ± 31 minutes; group B, 117 ± 30 minutes; P =.006) and myocardial ischemia times (group A, 96 ± 25 minutes; group B, 88 ± 20 minutes; P =.05) were significantly longer in group A. Mortality was not significantly different between groups (group A, 4.8%; group B, 0%). One patient in each group underwent secondary valve replacement, and all other patients had stable valve function. Freedom from aortic regurgitation of grade 2 or greater after 48 months was 93.0% in both groups. Conclusion: Repair of leaflet prolapse in conjunction with valve-preserving root replacement leads to midterm results that are equal to those of valve-preserving root replacement for morphologically intact leaflets. J Thorac Cardiovasc Surg 2001;122:270-7

Aortic valve preservation is a promising alternative to conventional composite replacement of aortic valve and ascending aorta. This approach may have a physiologic benefit compared with valve replacement similar to that seen in mitral valve reconstruction. We investigated aortic valve gradients at rest and during exercise in patients who had undergone valve-preserving aortic replacement and compared them with composite replacement of valve and aorta.Four groups were studied: nine patients underwent composite valve replacement (group A: valve diameter, 23 to 27 mm), eight patients underwent remodeling of the aortic root (group B), and another nine patients had reimplantation of the aortic valve (group C). Healthy volunteers were studied as a control group (group D). Using continuous-wave Doppler echocardiography, all patients were examined on a bicycle ergometer for aortic valve gradients (0 to 75 W).There were no differences among the groups with respect to age, body surface, left ventricular end-diastolic diameter, fractional shortening, or left ventricular mass. Maximum resting gradients were significantly elevated in group A compared with groups B, C, and D (group A: 21.3 +/- 7.1 mm Hg; group B: 9.0 +/- 4.5 mm Hg; group C: 8.6 +/- 3.7 mm Hg; group D: 4.9 +/- 1.6 mm Hg; p0.05). At 75 W, group A exhibited significantly higher gradients than all other groups (group A: 31.3 +/- 7.5 mm Hg; group B: 13.9 +/- 6.6 mm Hg; group C: 12.8 +/- 3.5 mm Hg; group D: 9. 2 +/- 1.9 mm Hg; p0.05). There was no significant difference among the other groups. Both valve-preserving groups had only insignificantly higher gradients than the control group.Our data strongly support the suggestion that preserving the aortic valve restores nearly normal hemodynamic function of the aortic valve. Long-term observations will have to prove the clinical relevance of restoring physiologic aortic valve hemodynamics.

To improve postoperative pulmonary reserve, we have employed parenchyma-sparing resections for central lung tumors irrespective of pulmonary function. The results of lobectomy, pneumonectomy, and sleeve resection were analyzed retrospectively.From October 1995 to June 1999, 422 typical lung resections were performed for lung cancer. Of these, 301 were lobectomies (group I), 81 were sleeve resections (group II), and 40 were pneumonectomies (group III).Operative mortality was 2% in group I, 1.2% in group II, and 7.5% in group III (group I and II vs. group III, p0.03). Mean time of intubation was 1.0+/-4.1 days in group I, 0.9+/-1.3 days in group II, and 3.6+/-11.2 days in group III (groups I and II vs. group III, p0.01). The incidence of bronchial complications was 1.3% in group I, none in group II, and 7.5% in group III (group I and II vs group III, p0.001). After 2 years, survival was 64% in group I, 61.9% in group II, and 56.1% in group III (p = NS). Freedom from local disease recurrence was 92.1% in group I, 95.7% in group II, and 90.9% in group III after 2 years (p = NS).Sleeve resection is a useful surgical option for the treatment of central lung tumors, thus avoiding pneumonectomy with its associated risks. Morbidity, early mortality, long-term survival, and recurrence of disease after sleeve resection are similar to those seen after lobectomy.

Background . Currently, isolated reconstruction of a regurgitant bicuspid aortic valve can be performed with adequate early results. Dilatation of the proximal aorta is known to be associated with this valve anomaly and may be partially responsible for the development of primary regurgitation or secondary failure of valve repair. We have used repair of the bicuspid valve with remodeling of the aortic root as an alternative to insertion of a composite graft. Methods . Between October 1995 and May 1999, 16 patients (12 men, 4 women, aged 35 to 73 years) were seen with a regurgitant bicuspid aortic valve and dilatation of the proximal aorta of more than 50 mm. All patients underwent repair of the valve using either coapting sutures alone (n = 12) or in combination with triangular resection of a median raphe (n = 4). Using a Dacron graft, the aortic root was remodeled and the ascending aorta (n = 16) and proximal arch (n = 4) replaced. Results . No patient died. The postoperative degree of aortic regurgitation was less than grade II in all patients. Valve function has remained stable in all patients between 2 and 43 months postoperatively. Conclusions . Reconstruction of the regurgitant bicuspid valve in the presence of proximal aortic dilatation is feasible with good results by combining the root remodeling technique with valve repair.

Background . Osteoporosis has been recognized as an important side effect of long-term and of pulsed steroid application after heart transplantation. Methods . In June 1989 a prospective clinical trial was started to study bone demineralization by quantitative computed tomographic scan. All patients received vitamin D and calcium. In group I (n = 30) synthetic calcitonin (40 Medical Research Council Standard Units subcutaneously per day was administered in 14-day cycles, whereas group II patients (n = 31) received a placebo preparation. Repeat trabecular and cortical quantitative computed tomographic scans of the thoracic (T12) and lumbar spine (L1, L2, L3) were obtained within 48 weeks after heart transplantation. Results . Expressed as the means of T12, L1, L2, and L3, trabecular bone density decreased significantly from 100 ± 24 to 79 ± 29 mg/mL within 3 weeks after heart transplantation, followed by a further reduction to 67 ± 29 mg/mL after 3 months in the calcitonin group. The values for cortical bone density decreased significantly from 229 ± 37 to 202 ± 40 mg/mL (calcitonin) 3 weeks after heart transplantation. Comparable results were obtained in the placebo group. In both groups bone density remained stable thereafter. Intergroup differences were not of statistical significance. Conclusions . In heart transplant recipients progressive trabecular bone demineralization is limited to the first 3 postoperative months. Thereafter, bone density remained stable. A positive effect of synthetic calcitonin in addition to prophylactic calcium and vitamin D application could not be proved by repeat quantitative computed tomography.

Focal adhesion kinase (FAK) is a crucial component of focal adhesion sites, transducing signals between the cytosol and the extracellular matrix. The translocation of FAK to focal adhesion sites and its functional activation by tyrosine phosphorylation leads to the formation of large multi-molecular focal adhesion complexes. The three-dimensional structure of FAK consists of a tyrosine kinase domain and two large non-catalytic regions. The N-terminal FERM domain is involved in auto-inhibition of the kinase by blocking a phosphorylation site (Tyr576/577)[1], and also includes a basic patch for anchoring FAK to membrane-embedded PIP2. The exposure of this phosphorylation site induces the maximum activity of FAK. We tested if mechanical forces as they are present at focal adhesion sites can induce an allosteric switch to an active state of FAK with an exposed phosphorylation site, using Molecular Dynamics simulations of membrane-bound and unbound FAK.We indeed find mechanical forces propagated onto FAK when tethered between the membrane and the cytoskeleton to remove the auto-inhibitory FERM domain from the kinase domain of FAK. We instead observe an only partial FAK activation upon anchoring FAK to the membrane in the absence of mechanical force. The mechano-transduction mechanism of FAK can explain how FAK acts as a force sensor, translating mechanical forces at the focal adhesion site into downstream biochemical signal events including the MAPK pathway.[1] D. Lietha, X. Cai, D.F.J. Ceccarelli, Y. Li, M. D. Schaller and M. J. Eck. Cell, 2007(129), 1177-1187

Background A systemic inflammatory response after open heart operation may be responsible for hyperdynamic circulatory instability and organ dysfunction. To what extent mediator release is involved needs to be clarified. Methods Ten patients with postoperative hyperdynamic circulatory dysregulation (group I) requiring application of α -constrictors and 10 patients with routine cardiac procedures and stable postoperative hemodynamic indices (group II) were analyzed for mediator release and metabolic and hemodynamic changes until the third postoperative day. Results Group I patients showed a significantly increased cardiac index and decreased systemic vascular resistance after bypass (cardiac index, group I: 5.2 ± 1.2 l · min −1 · m −2 , group II: 2.5 ± 1.6 L · min −1 · m −2 ; systemic vascular resistance, group I: 495 ± 204 dyne · s · cm −5 , group II: 1,356 ± 466 dyne · s · cm −5 ) and at 3 hours (cardiac index, group I: 4.4 ± 0.8 L · min −1 · m −2 , group II: 2.9 ± 0.6 L · min −1 · m −2 ; systemic vascular resistance, group I: 567 ± 211 dyne · s · cm −5 , group II: 1,053 ± 273 dyne · s · cm −5 ). Significantly higher serum levels of interleukin-6 were assessed in group I (postbypass, group I: 6,812 ± 9,293 pg/mL, group II: 295 ± 303 pg/mL; 3 hours, group I: 3,474 ± 5,594 pg/mL, group II: 286 ± 296 pg/mL). Concentrations of elastase, tumor necrosis factor, soluble tumor necrosis factor receptor, and interleukin-8 were elevated in group I (not significant). Early postoperative levels of soluble E-selectin and soluble intercellular adhesion molecule were also higher in group I (not significant). Continuously increased levels of endotoxin could be detected in only 3 of 10 patients in group I. Severe lactic acidosis (≥5 mmol/L) occurred in group I only. Conclusions Postoperative hyperdynamic instability after open heart operations appears to be associated with a certain pattern of mediator release. In particular, interleukin-6 appears to be involved in circulatory dysregulation and metabolic derangement.

Nowadays in many European heart centers the activation of the fibrinolytic system, always occurring during cardiopulmonary bypass, is routinely reduced by high-dose application of the proteinase inhibitor aprotinin (total of >4 million KIU). In this study parameters of myocardial ischemic injury were investigated with the aim of identifying further benefits of aprotinin, particularly the protection of the myocardium during the ischemic period of aortic crossclamping. Forty patients with coronary artery disease who underwent aorta-coronary bypass grafting were randomly and in a double-blind fashion divided into two groups, one that received high-dose aprotinin therapy and one that received only saline solution. Markers such as troponin T, with high specificity for detection of myocardial ischemia and infarction, and markers with more general specificity such as creatine kinase, its isoenzyme, and lactate dehydrogenase showed significantly increased values after ischemia in both groups. In patients who received high-dose aprotinin therapy 3 days after cardiopulmonary bypass all parameters measured showed significantly lower levels compared with those in the control group. Therefore we can presume that the application of high-dose aprotinin provides myocardial protection from perioperative ischemic injury. (J THORAC CARDIOVASC SURG 1995;109:1164-72)

Donor lungs contain large amounts of passenger leukocytes which are transferred to the recipient by organ transplantation. In this study we have analysed the fate of these cells and have studied the population of donor leucocytes detectable in the blood circulation of ten lung transplanted patients during the first postoperative weeks. To this aim we have applied immunocytological as well as flow cytometric analyses using monoclonal antibodies against polymorphic HLA class I antigens that differed between donor and recipient as well as antibodies against cell differentiation markers. The results demonstrate that donor cells can be detected in the circulation of all lung transplanted patients but there is a considerable interindividual variability between 0.9% and 17.5% (mean 5.1%) on postoperative day 3. Cells were usually detectable for 2–4 weeks and had disappeared in all patients after 1 month. The circulating donor cells consisted exclusively of lymphocytes. T cells were the predominant population, most of which seemed to be CD45R0+, but B and NK (natural killer) cells were also present. Probably due to the small numbers of patients studied no correlation between clinical parameters and the extent of donor lymphocyte persistence; there were no clinical graft-versus-host reactions. The findings demonstrate the regular existence of a transient (macro)chimerism due to passenger lymphocytes in the early phase after lung transplantation. The immunological function and the relation between this phenomenon and the long-term microchimerism which frequently develops after solid organ transplantation remain unclear.

Disordered proteins have the capacity to self-assemble from random coils to partial or complete folded structures. Such combination of amorphous/ordered phases within the protein structure is determined by the aminoacid sequence as well as enviromental factors, such as flow or confinement, and it is expected that the proportion of each phase would play a role in the activity and biological function of the protein. Nevertheless, modeling the molecular arrangement of disordered/folded structures poses a challenge and it has been possible only for few short fragments or individual proteins. For macromolecular complexes, computationally analyzing properties such as dynamics, mechanics or heat transfer requires taking the polymeric nature of chain entanglements into account. We devised a new approach based on an existing collapsing-annealing Molecular Dynamics protocol [1] for building amorphous phases of long disordered protein chains. We adapted it to also include structured phases such as beta-sheet units, by steering parts of the protein chains into the experimentally known conformations. As a proof-of-concept, we successfully set up a model of 100 intrinsically disordered chains each comprising 500 aminoacids of silk spidroin. This resulted in a compact protein-only system (20 nm)ˆ3 in size. Then, we introduced silk crystalline units based on x-ray scattering data, highlighting that our newly-develop protocol can handle composite materials with partial structure as well. Our full detail atomistic structure is the most comprehensive silk model computationally studied to date, up to our knowledge. We believe our approach to be valuable for a wide range of Molecular Dynamics simulations, in which the disordered polymeric component of proteins dominates in the assembly or biomaterial.[1] Cruz-Chu, E. R et al. Faraday Discussions (2009) 143, 47-62.

Mechanical pulling forces have been shown to significantly alter the rate of redox reactions in various thiol/disulfide exchange systems [1]. However, it has been questioned if force can directly affect the electron affinity of such redox systems [2]. We here investigated the impact of mechanical force on disulfide bonds. We used hybrid quantum/molecular mechanical simulations of cystine in water and extensive conformational sampling to estimate redox potentials under pulling forces in the range of 0 to 3300 pN. We found that forces as small as a few 100 pN alter the redox potential by several 100 mV, which is significant regarding that similar variations are found among simple reducing agents or upon mutations in thioredoxin. Thus, mechanical stress as proteins in living organisms often experience can tune biochemical reactivity not only by protein unfolding and exposure of reaction sites but also by directly tuning the electronic energy of a bond.[1] Wiita et al. 2007. Nature. 450:124-127; Jiminez et al. 2009. Nat. Struct. Mol. Biol. 16: 890-896.[2] Kucharski et al. 2009. Angew. Chem. Int. Ed. 48:7040-7043.View Large Image | View Hi-Res Image | Download PowerPoint Slide

Silk is an intriguing protein-based material that combines elasticity and strength to an extent not yet reached by any synthetic material today. Silk fibers are composed of highly-ordered beta-sheet crystals and an amorphous peptide matrix that both contribute to its outstanding mechanical properties. However, how the way of organization of these two components affects silk fiber mechanics has remained unclear. To quantify the mechanics of silk fibers and its components, we here in a bottom-up approach extract elastic and rupture parameters of silk composite units from all-atom molecular simulations and a novel force distribution analysis serve as input for finite element analysis [1,2]. By doing so, we can derive macroscopic fiber mechanics from the nano-structure, in quantitative agreement with experiments. One of our most striking predictions is that a serial arrangement of silk crystals in the fiber, as commonly observed in form of lamellae for other block copolymers, outperforms a random distribution, in sharp contrast to the current view of silk fiber organization [3]. We also show why the typical beta-strand length of eight residues in silk crystals is mechanically optimal [2]. Finally, a smaller cross-sectional area of silk crystals (∼1nm2) in fibers provides a better reinforcement of the amorphous phase than larger ones. [3] We expect our straightforward multiscale approach to serve as a guideline for the design of silk-like synthetic materials.1. S Xiao, W Stacklies, M Cetinkaya, B Markert, and F Graeter. Biophys J, 96(10):3997–4005, May 2009.2. S Xiao, W Stacklies, C Debes, and F Graeter. Soft Matter, 2010.3. M Cetinkaya, S Xiao, B Markert, W Stacklies, and F Graeter. in review, 2010.

We describe the case of a 58-year-old female patient who underwent redo mitral valve replacement and remained in heart failure. The diagnosis of a left ventricular-right atrial fistula was made. The fistula was closed surgically with a patch of autologous pericardium. The patient improved immediately after the operation and has been asymptomatic since.

We reviewed 78 patients with Hylamer acetabular liners (DePuy-Dupont Orthopedics, Warsaw, IN), with a mean follow-up of 3.8 years (range, 2-6 years), for signs of osteolysis secondary to polyethylene wear. Nine patients (11.5%) showed osteolysis greater than 1 cm2. One patient had a greater trochanter fracture through a lytic area, one patient required a revision at 4 years for severe acetabular and femoral lysis with lesser trochanter fracture, and a second patient is awaiting revision.

Protein folds have been invented and adopted under various evolutionary constraints. The question arises how general mechanical attributes that control protein function have been sampled by the evolving protein domain repertoire in the varying biological environment.We assessed three measures, namely flexibility, foldability, and mechanical strength, for ∼100,000 protein domains, using geometrical sampling (Concoord), contact order, and coarse-grained protein unfolding, respectively. In general, we find high mechanical stability to involve low protein flexibility and low foldability.In order to reconstruct protein architecture evolution, we used infor-mation embedded in a structural genomic census of fold architectures defined by a phylogenomic analysis of 185 completely sequenced genomes using advanced hidden Markov models. Interestingly, flexibility is found to increase in evolution, hinting towards a fine-tuning of protein function during evolution towards dynamic regulation.Finally, our work can explain how proteins as an intricate network of inter-molecular bonds were designed by evolution as a response to mechanical stress.

ADAMTS13 is a plasma zinc metalloproteinase crucial for primary haemostasis, the enzymatic activity of which is biomechanically controlled. Shear stress-induced partial unfolding of its substrate, the von Willebrand factor (vWF) A2 domain, is essential for efficient cleavage of the target 1605Y-1606M peptide bond. However, the mechanisms of stress-activated vWF A2 recognition and cleavage by ADAMTS13 have yet to be fully resolved.From our newly developed Molecular Dynamics (MD) based force distribution analysis, we find force to propagate in the cleavage-ready vWF A2 unfolding intermediate such that the target peptide bond is selectively pre-stressed and thus putatively weakened for cleavage by ADAMTS13. MD simulations of the ADAMTS13-vWF A2 complex allowed us to identify residues adjacent to the cleaved peptide bond that are relevant for efficient A2 binding. Subsequent QM calculations using semi-empirical PM6-DH method provided relative binding energies in good agreement with experiments. The force-dependent hydrolysis of the Y-M peptide bond was explored by QM and hybrid QM/MM calculations. Mechanical stretching, induced by a shear stress, facilitates the cleavage reaction. Finally, the enzyme reduces the entropic cost of substrate binding by increasing fast-scale dynamics in the regions distant from the catalytic site (e.g. disintegrin domain).Overall, our study reveals the subtle details of ADAMTS13 biomechanical function.