Multispinon continua at zero and finite temperature in a near-ideal Heisenberg chain.

The space-and time-dependent response of many-body quantum systems is the most informative aspect of their emergent behavior. The dynamical structure factor, experimentally measurable using neutron scattering, can map this response in wave vector and energy with great detail, allowing theories to be quantitatively tested to high accuracy. Here, we present a comparison between neutron scattering measurements on the one-dimensional spin-1/2 Heisenberg antiferromagnet KCuF3, and recent state-of-the-art theoretical methods based on integrability and density matrix renormalization group simulations. The unprecedented quantitative agreement shows that precise descriptions of strongly correlated states at all distance, time, and temperature scales are now possible, and highlights the need to apply these novel techniques to other problems in low-dimensional magnetism.

[Reconstruction of osteochondral defects with a collagen I hydrogel. Results of a prospective multicenter study]. / Rekonstruktion von Gelenkknorpeldefekten mit einem Kollagen-I-Hydrogel. Ergebnisse einer prospektiven Multicenterstudie.

STUDY GOALS: The aim of the study was to evaluate the therapeutic benefit of CaReS®, a type I collagen hydrogel-based autologous chondrocyte implantation technique, for the treatment of osteochondral defects of the knee (Outerbridge grades III and IV) within a prospective multicenter study. MATERIAL AND METHODS: A total of 116 patients in 9 clinical centers were treated with CaReS between 2003 and 2008. The Cartilage Injury Evaluation Package 2000 of the International Cartilage Repair Society (ICRS) was employed for data acquisition and included the subjective International Knee Documentation Committee score (IKDC score), the pain level (visual analog scale, VAS), the physical and mental SF-36 score, the overall treatment satisfaction and the functional IKDC status of the indexed knee. Follow-up evaluation was performed 3, 6 and 12 months after surgery and annually thereafter. RESULTS: The mean defect size treated was 5.4 ± 2.7 cm(2) with 30% of the cartilage defects being ≤4 cm(2) and 70% ≥4 cm(2). The mean follow-up period was 30.2 ± 17.4 months (minimum 12 months and maximum 60 months). The mean IKDC score significantly improved from 42.4 ± 13.8 preoperatively to 70.5 ± 18.7 (p < 0.01) in the mean follow-up period. Global pain level significantly decreased (p < 0.001) from 6.7 ± 2.2 preoperatively to 3.2 ± 3.1 at the latest follow-up. Both the physical and mental components of the SF-36 score significantly increased. At the latest follow-up 80% of the patients rated the overall treatment satisfaction as either good or very good. The functional IKDC knee status clearly improved from preoperative to the latest follow-up when 23.4% of the patients reported having no restriction of knee function (I), 56.3% had mild restriction (II), 17,2% had moderate restriction (III) and 3.1% revealed severe restriction (IV). CONCLUSIONS: The CaReS technique is a clinically effective and safe method for the reconstruction of isolated osteochondral defects of the knee joint and reveals promising clinical outcome up to 5 years after surgery. A longer follow-up period and larger patient cohorts are needed to evaluate the sustainability of CaReS treatment.

Dissipative quantum Church-Turing theorem.

We show that the time evolution of an open quantum system, described by a possibly time dependent Liouvillian, can be simulated by a unitary quantum circuit of a size scaling polynomially in the simulation time and the size of the system. An immediate consequence is that dissipative quantum computing is no more powerful than the unitary circuit model. Our result can be seen as a dissipative Church-Turing theorem, since it implies that under natural assumptions, such as weak coupling to an environment, the dynamics of an open quantum system can be simulated efficiently on a quantum computer. Formally, we introduce a Trotter decomposition for Liouvillian dynamics and give explicit error bounds. This constitutes a practical tool for numerical simulations, e.g., using matrix-product operators. We also demonstrate that most quantum states cannot be prepared efficiently.

Influence of phosphatidylserine on cognitive performance and cortical activity after induced stress.

The aim of this study was to investigate the effect of phosphatidylserine (PS) on cognition and cortical activity after mental stress. After familiarization, 16 healthy subjects completed cognitive tasks after induced stress in a test-re-test design (T1 and T2). Directly after T1, subjects were assigned double-blind to either PS or placebo groups followed by T2 after 42 days. At T1 and T2, cortical activity was measured at baseline and immediately after stress with cognitive tasks using electro-encephalography (EEG). EEG was recorded at 17 electrode positions and fast Fourier transforms (FFT) determined power at Theta, Alpha-1, Alpha-2, Beta-1 and Beta-2. Statistics were calculated using ANOVA (group x trial x time). The main finding of the study was that chronic supplementation of phosphatidylserine significantly decreases Beta-1 power in right hemispheric frontal brain regions (F8; P < 0.05) before and after induced stress. The results for Beta-1 power in the PS group were connected to a more relaxed state compared to the controls.

[Refixation of the biceps tendon onto the radial tuberosity using two suture anchors]. / Refixation der distalen Bizepssehne an der Tuberositas radii mit zwei Spreizankern.

OBJECTIVE: Reinsertion of the distal biceps tendon onto the radial tuberosity restoring full force of flexion and supination. INDICATIONS: Distal biceps tendon avulsion from the radial tuberosity. Acute and chronic tears with a tendon stump, which can be mobilized and reduced to the radial tuberosity in flexion and supination. CONTRAINDICATIONS: Tears of the musculotendinous junction. Chronic distal biceps tendon tears with wide retraction and the need for tendon graft augmentation. Severe atrophy of the biceps muscle. SURGICAL TECHNIQUE: In supination, the skin is incised longitudinally for 4 cm, centered over the medial border of the radial tuberosity. Incision starts 2 cm distal from the humeroradial joint line. Bluntly the distal biceps tendon stump is found and mobilized. Preparation and debriding of the radial tuberosity sparing neurovascular structures. Crossing vessel branches are ligated, if needed. Positioning of two spreading anchors into the radial tuberosity and reinsertion of the tendon stump. POSTOPERATIVE MANAGEMENT: Adjustable elbow movement orthosis adapted to tendon quality and tissue tension for 6 weeks without active flexion or supination. Degree of extension is gradually increased by 20° every 2 weeks. After orthosis treatment is finished after 6 weeks, flexion and supination with weights is not allowed for another 6 weeks. RESULTS: In a retrospective study of 30 patients with a mean follow-up of 45 months (range 15-80 months), the clinical outcome was good or excellent in 99% of cases. On average, a Mayo Elbow Performance Score of 93 points (range 65-100 points) and a QuickDash of 5 points (range 0-39 points) were achieved.

Pandemic (H1N1) 2009 influenza A virus infection associated with respiratory signs in sloth bears (Melursus ursinus).

In 2009, a pandemic influenza A virus (pH1N1) spread globally in humans and infected a broad range of captive animals with close human contact. In February 2014, a pH1N1 virus was isolated from a sloth bear with respiratory signs at a US zoo, demonstrating that recurring epidemics present an ongoing threat to animals, including threatened species. This is the first report of pH1N1 infection in sloth bears. To understand the sloth bear virus within the global context of pH1N1, phylogenetic trees were inferred including full-length sequences from available non-human, non-swine hosts, representing four families in the order Carnivora and one order of birds. A combination of phylogenetic and epidemiological evidence strongly suggests the sloth bear was infected with a human-origin pH1N1 virus, supporting the implementation of biosecurity measures to protect human and animal health.

[Sliding osteotomy of the tibial tuberosity in patellofemoral instability]. / Verschiebeosteotomie der Tuberositas tibiae bei patellofemoraler Instabilität.

OBJECTIVE: The development of a stable patellofemoral joint by distal realignment with normal positioning of the patella. INDICATIONS: Patellofemoral instability with increased tibial tubercle to trochlear groove (TT-TG) distance ≥ 20 mm and higher Caton-Deschamps patellar height index ≥ 1.3. CONTRAINDICATIONS: Open epiphyseal and apophyseal plates of the proximal tibia, normal TT-TG distance with normal patellar height, and high-grade chondral lesions of the patellofemoral joint (ICRS grades 3 and 4). SURGICAL TECHNIQUE: Examination of the knee joint under anesthesia and evaluation of stability and mediolateral translation of the patella. Diagnostic knee arthroscopy and treatment of chondral or osteochondral lesions. Lateral approach to the tibial tuberosity with soft tissue mobilization and exposure of the patellar tendon. Osteotomy is performed in the frontal plane, creating a fragment at least 6 cm long. The tuberosity is slid into the desired position, medially and distally, if necessary, according to preoperative analysis and planning, followed by careful drilling of the posterior tibial cortex and lag screw osteosynthesis. POSTOPERATIVE MANAGEMENT: Partial weight-bearing of 20 kg in a MECRON knee brace for 6 weeks. Mobilization 0/0/90° from the MECRON knee brace without active knee extension. Isometric training of the thigh muscles with the knee fully extended. RESULTS: With meticulous planning and implementation, and in cases of severe trochlear dysplasia combined with medial patellofemoral ligament reconstruction, the technique of sliding osteotomy of the tibial tuberosity has a high success rate.

[Gracilis tendon augmented reconstruction of the medial patellofemoral ligament with soft tissue fixation at the patellar insertion site]. / Ersatz des medialen patellofemoralen Ligaments durch autologe Gracilissehne mit implantat- und bohrkanalfreier patellarer Fixation.

OBJECTIVE: Reconstruction of the medial patellofemoral ligament with autologous tendon augmentation and soft tissue fixation at the patellar insertion with resorbable suture material. INDICATIONS: Patellofemoral instability due to insufficiency of the medial passive stabilizers and dysplastic trochlea. CONTRAINDICATIONS: Primary traumatic dislocation of the patella without risk factors for patellar redislocation, severe osteoarthritis of the patellofemoral joint, infection. SURGICAL TECHNIQUE: Diagnostic arthroscopy to evaluate cartilage and shape of trochlea and to treat associated injuries. Harvesting of the gracilis tendon and arming with resorbable suture material. Transfer of the tendon through the medial capsule in the anatomical layer of the MPFL and weaving in u-shape through the capsule and periosteum near the patella. Soft tissue fixation with resorbable suture material. Anatomical reconstruction of the femoral insertion site. Femoral fixation with interference screw. POSTOPERATIVE TREATMENT: For 4 weeks, partial (20 kg) weight bearing with crutches; cast with physiotherapy (limited ROM extension, flexion 0-0-90°). Thereafter free range of motion and full weight bearing. RESULTS: 27 patients (age 12-45 years) with patellofemoral instability underwent reconstruction of the medial patellofemoral ligament. Clinical follow-up was assessed up to 12 months postoperatively. After 1 year, the Kujala and Flandry scores increased from preoperatively 72 points to 95 points and 65.7 points to 89.9 points, respectively. One redislocation was observed. Patient satisfaction was significantly increased at 6 months postoperatively. Reconstruction of the medial patellofemoral ligament shows good clinical results after 12 months.

Randomized trial comparing early postoperative irradiation vs. the use of nonsteroidal antiinflammatory drugs for prevention of heterotopic ossification following prosthetic total hip replacement.

PURPOSE: A randomized trial was undertaken to assess the comparative efficacy of early postoperative irradiation with either 5 or 7 Gy vs. the use of nonsteroidal antiinflammatory drug (NSAID) for prevention of heterotopic ossification (HO) following prosthetic total hip replacement (THP). METHODS AND MATERIALS: Between 1993 and 1994, 301 patients were randomized to receive postoperative irradiation (5 or 7 Gy) or NSAID. One hundred and thirteen patients were treated with NSAID (indomethacin 2 x 50 mg/day for 1 week), 93 patients were irradiated with a single 7 Gy fraction, 95 patients with a single 5 Gy fraction. The treatment volume included the soft tissues between the periacetabular region of pelvis and the intertrochanteric portion of the femur. X-rays of treated hips were obtained immediately and 6 months after surgery. Heterotopic ossification was scored according to the Brooker Grading system. One hundred patients receiving no prophylactic therapy after total hip arthroplasty between 1988 and 1992, were analyzed and defined as historical control group. RESULTS: Incidence of heterotopic ossification was 16.0% in NSAID-group (Brooker Score I: 8.0%; II: 6.2%; III: 1.8%; IV: 0%), 30.1% in 5 Gy group (Brooker Score I: 24.7%; II: 4.3%; III: 1.1%; IV: 0%), and 11.1% in 7 Gy group (Brooker Score I: 11.6%; II: 0%; III: 0%; IV: 0%). Regarding overall heterotopic ossification there was a significant difference between the NSAID group and the 5 Gy group (p < .015), respectively, between the 7 Gy group and the 5 Gy group (p < .0001). No significant difference was noted in the influence of overall HO between the NSAID and the 7 Gy group (p > 0.3). Analyzing the clinically significant HO (Brooker Score III and IV) patients irradiated with 7 Gy developed less HO than those treated with NSAID (p = 0.003). Incidence of HO was greater in the untreated historical control group (Brooker Score I: 26%; II: 15%; III: 19%; IV: 5%) than in all three prophylacticly treated groups. CONCLUSION: Prophylactic irradiation of the operative site after hip replacement with single a 7 Gy fraction is the most effective postoperative treatment schedule in prevention of clinically significant heterotopic ossification. This therapy modality is more effective than irradiation with a single 5 Gy fraction or use of NSAID.

Preoperative irradiation versus the use of nonsteroidal anti-inflammatory drugs for prevention of heterotopic ossification following total hip replacement: the results of a randomized trial.

PURPOSE: Previous studies showed the effectiveness of early preoperative (4 h before operation) irradiation for prevention of heterotopic ossification (HO) after total hip replacement. This procedure can result in logistic problems, if there is a great distance between the department of radiotherapy and the orthopedic clinic. To avoid these organizational problems a prospective study was undertaken to analyze the effectiveness of preoperative irradiation on the day preceding surgery (16-20 h before operation). METHODS AND MATERIALS: Between 1995 and 1996, 100 patients were randomized to receive a prophylactic therapy for prevention of heterotopic ossification. Forty-six patients were irradiated with 7 Gy single dose within 16-20 h before operation. Fifty-four patients were treated with nonsteroidal anti-inflammatory drugs (NSAID) (Voltaren resinat 2 x 75 mg/day for 2 weeks). Heterotopic ossification was scored according to the Brooker Grading system. One hundred patients receiving no prophylactic therapy after total hip arthroplasty between 1988 and 1992 were analyzed and defined as the historical control group. RESULTS: Incidence of heterotopic ossification was 47.8% in the 7 Gy preoperative group (Brooker Score I: 36.9%; II: 8.7%; III: 2.2%; IV: 0%) and 11.1% in the NSAID group (Brooker Score I: 9.3%; II: 1.8%; III: 0%; IV: 0%). Regarding overall heterotopic ossification there was a significant difference between the NSAID group and the 7 Gy group (p < 0.01). Analyzing the clinically significant heterotopic ossification (Brooker Score III and IV) there was no significant difference between the two treatment arms (p > 0.05). In the untreated historical control group the incidence of heterotopic ossification was 65% (Brooker Score I: 26%; II: 15%; III: 19%; IV: 5%). Referring to overall and to clinically relevant heterotopic ossification the incidence of HO was greater in the control group than in the prophylactically treated groups (p < 0.05). CONCLUSION: Irradiation within 16-20 h before operation and use of NSAID (Voltaren resinat) can reduce the incidence of clinically relevant heterotopic ossification after total hip replacement.

The chondrogenic potential of human bone-marrow-derived mesenchymal progenitor cells.

Mesenchymal progenitor cells provide a source of cells for the repair of musculoskeletal tissue. However, in vitro models are needed to study the mechanisms of differentiation of progenitor cells. This study demonstrated the successful induction of in vitro chondrogenesis with human bone-marrow-derived osteochondral progenitor cells in a reliable and reproducible culture system. Human bone marrow was removed and fractionated, and adherent cell cultures were established. The cells were then passaged into an aggregate culture system in a serum-free medium. Initially, the cell aggregates contained type-I collagen and neither type-II nor type-X collagen was detected. Type-II collagen was typically detected in the matrix by the fifth day, with the immunoreactivity localized in the region of metachromatic staining. By the fourteenth day, type-II and type-X collagen were detected throughout the cell aggregates, except for an outer region of flattened, perichondrial-like cells in a matrix rich in type-I collagen. Aggrecan and link protein were detected in extracts of the cell aggregates, providing evidence that large aggregating proteoglycans of the type found in cartilaginous tissues had been synthesized by the newly differentiating chondrocytic cells; the small proteoglycans, biglycan and decorin, were also detected in extracts. Immunohistochemical staining with antibodies specific for chondroitin 4-sulfate and keratan sulfate demonstrated a uniform distribution of proteoglycans throughout the extracellular matrix of the cell aggregates. When the bone-marrow-derived cell preparations were passaged in monolayer culture as many as twenty times, with cells allowed to grow to confluence at each passage, the chondrogenic potential of the cells was maintained after each passage.

Prevention of heterotopic ossification after total hip replacement. A prospective, randomised study using acetylsalicylic acid, indomethacin and fractional or single-dose irradiation.

We have carried out a prospective, randomised study of prophylaxis for heterotopic ossification (HO) comparing indomethacin for 7 and 14 days, acetylsalicylic acid, and fractional (4 x 3 Gy) or single exposure of 5 or 7 Gy irradiation after operation. We initially had 723 patients (733 hip replacements), but after withdrawals there were 685 hips of which 18.4% developed HO; 14% were grade I, 2.9% grade II and 1.5% grade III of the Brooker classification. We compared the results between these groups with those of a matched control series and found that indomethacin, 2 x 50 mg for 7 and 14 days, and postoperative irradiation of 4 x 3 Gy or 1 x 7 Gy, significantly reduced the development of HO compared with the control group. Patients in the acetylsalicylic acid group and those with a single irradiation of 5 Gy after operation developed significantly more ossification than those in the indomethacin and other irradiation groups. We suggest the use of 2 x 50 mg of indomethacin with mucoprotection for seven days as prophylaxis against HO after total hip replacement for all patients. A single irradiation of 7 Gy is recommended for patients who have developed HO after previous operations or to whom administration of indomethacin is contraindicated.

[Minimally invasive retrograde drilling of osteochondral lesions of the femur using an arthroscopic drill guide]. / Minimal-invasive retrograde Anbohrung der Osteochondrosis dissecans des Femurkondylus mit einem speziellen Zielinstrumentarium.

OBJECTIVE: Retrograde drilling for penetration of subchondral sclerotic bone in osteochondrosis dissecans (OCD) of the femoral condyle with preserved cartilage integrity. Hereby, revascularization of the OCD and immigration of bone marrow cells to achieve stable reintegration of the OCD into the surrounding subchondral bone. INDICATIONS: Stable juvenile and adult osteochondrosis dissecans (stage I-II of the International Cartilage Repair Society (ICRS) classification) of the medial and lateral femoral condyle with an intact articular surface and surrounding sclerosis zone, which is visible in the x-ray. CONTRAINDICATIONS: OCD stage III-IV of the ICRS grading scale. Relative contraindication: preceding retrograde drilling. SURGICAL TECHNIQUE: Arthroscopic inspection and palpation of the cartilage defect. Minimal incision over the M. vastus medialis (when the defect is located in the medial condyle) or the M. vastus lateralis (when the defect is located in the medial condyle). Preparation and dissection of the fascia of the vastus muscle. Insertion of retractors underneath the vastus muscle to expose the metaphysis of the distal femur. Intraarticular positioning of the arthroscopic drill guide, placement of the wire guide and a Kirschner(K) wire on the femur metaphysis and retrograde drilling with a 2.0-2.2 mm K wire under radiographic visualization. Length measurement of the intraosseous wire distance. Switch the guide mechanism to a multiple hole drill guide and, depending on the defect size, insertion of a further 7-10 K wires of same thickness and defined length. POSTOPERATIVE MANAGEMENT: Sterile bandage and slightly compressive dressing. Continuous active and passive knee motion. Weight bearing of 20 kg for 6 weeks, with subsequent transition to continuous weight bearing. Radiographic controls at 6 and 12 weeks postoperatively. In case of a persistent sclerosis zone in the control x-ray or clinical abnormalities, control MRI is indicated. RESULTS: A total of 55 patients with a mean age of 19.6 years were treated using the described technique: 49 patients (89.1%), and 54 knees respectively (35 juvenile OCD, 19 adult OCD), were seen with a mean follow-up of 37.9 months. An improvement was observed in 81.6% of the knees using the radiographic score, i.e., a mean improvement of 1.13 of the radiographic score published by Rodegerdts and Gleissner (preoperative 3.04 vs. postoperative 1.91). Juvenile OCD showed better radiographic results overall (88.2% healing) than adult OCD (66.7% healing).

Dephasing and the steady state in quantum many-particle systems.

We discuss relaxation in bosonic and fermionic many-particle systems. For integrable systems, time evolution can cause a dephasing effect, leading for finite subsystems to steady states. We explicitly derive those steady subsystem states and devise sufficient prerequisites for the dephasing to occur. We also find simple scenarios, in which dephasing is ineffective and discuss the dependence on dimensionality and criticality. It follows further that, after a quench of system parameters, entanglement entropy will become extensive. This provides a way of creating strong entanglement in a controlled fashion.

Anterior cruciate ligament constructs fabricated from human mesenchymal stem cells in a collagen type I hydrogel.

BACKGROUND: Disruptions of the anterior cruciate ligament (ACL) of the knee joint are common and are currently treated using ligament or tendon grafts. In this study, we tested the hypothesis that it is possible to fabricate an ACL construct in vitro using mesenchymal stem cells (MSC) in combination with an optimized collagen type I hydrogel, which is in clinical use for autologous chondrocyte transplantation (ACT). METHODS: ACL constructs were molded using a collagen type I hydrogel containing 5 x 10(5) MSC/mL and non-demineralized bone cylinders at each end of the constructs. The constructs were kept in a horizontal position for 10 days to allow the cells and the gel to remodel and attach to the bone cylinders. Thereafter, cyclic stretching with 1 Hz was performed for 14 days (continuously for 8 h/day) in a specially designed bioreactor. RESULTS: Histochemical analysis for H and E, Masson-Goldner and Azan and immunohistochemical analysis for collagen types I and III, fibronectin and elastin showed elongated fibroblast-like cells embedded in a wavy orientated collagenous tissue, together with a ligament-like extracellular matrix in the cyclic stretched constructs. No orientation of collagen fibers and cells, and no formation of a ligament-like matrix, could be seen in the non-stretched control group cultured in a horizontal position without tension. RT-PCR analysis revealed an increased gene expression of collagen types I and III, fibronectin and elastin in the stretched constructs compared with the non-stretched controls. DISCUSSION: In conclusion, ACL-like constructs from a collagen type I hydrogel, optimized for the reconstruction of ligaments, and MSC have been fabricated. As shown by other investigators, who analyzed the influence of cyclic stretching on the differentiation of MSC, our results indicate a ligament-specific increased protein and gene expression and the formation of a ligament-like extracellular matrix. The fabricated constructs are still too weak for animal experiments or clinical application and current investigations are focusing on the development of a construct with an internal augmentation using biodegradable fibers.

[Nail-patella syndrome. A 4-generation family study]. / Das Nail-Patella-Syndrom. Eine Familienstudie über 4 Generationen.

Five cases of hereditary onycho-osteodysplasie are reported. All of the family members presented dysplastic nails. Hypoplastic patella, elbow dysplasia or iliac horns were shown in variable expression. We've seen no other anomalies especially nephropathy did not occur.

The influence of variations of the coracoacromial arch on the development of rotator cuff tears.

In order to define the geometry of the coracoacromial arch in both its bony and soft parts and to bring it into relationship with rotator cuff tears, 54 cadaver shoulders (from subjects aged 47-90 years) were dissected and X-rayed (anteroposterior projection and supraspinatus outlet view). Partial rotator cuff tears were assessed additionally by transillumination and polarized microscopy. After transfixation of the coracoacromial arch with a polyurethane mould, sections were made along the coracoacromial ligament. The morphology of the acromion was described following the classification of Bigliani et al. [5]. Amongst other parameters, measurements were taken between the long axis of the scapula, the spina, and the acromion. In 19 of 22 cases, a traction osteophyte was associated with rotator cuff tears. In incomplete tears, spurs were completely encased within the ligament and did not impair the subacromial space. The number of rotator cuff tears was significantly increased in shoulders with "curved" acromia, flat acromial slope, and increased angle between the scapular plane and the spina (intact, mean 58 degrees; tears, mean 47 degrees). The morphology of the subacromial space was secondarily determined by this angle. In contrast to Bigliani et al. we were unable to find a "hooked" acromion. These results indicate that the combination of a flat and curved acromion or a position of the acromioclavicular joint above the cranial pole of the glenoid must be regarded as considerable risks for the development of rotator cuff tears. The concept of anterior acromioplasty is supported by our results.

Studies on the extraction of DesPro(2)-Val15-Leu17-aprotinin from the culture broth of a recombinant Saccharomyces cerevisiae.

The application of an aqueous two-phase system is described for the extraction of DesPro(2)-Val15-Leu17-aprotinin from yeast culture supernatant, using native chymotrypsin as affinity ligand. The interaction is driven by hydrophobic forces and leads to the accumulation of the aprotinin-chymotrypsin complex in the salt-rich (bottom) phase of a polyethyleglycol/salt system. The complex may be dissociated at low pH values. The separation of the recombinant aprotinin and the protease required chromatographic processes, which proved difficult to interface with the affinity extraction.

Rapid purification of DesPro(2)-Val15-Leu17-aprotinin from the culture broth of a recombinant Saccharomyces cerevisiae.

A rapid two-step procedure has been developed for the purification of Despro(2)-Val15-Leu17-aprotinin from the culture supernatant of a recombinant yeast by affinity and ion-exchange chromatography. DesPro(2)-Val15-Leu17-aprotinin was purified to homogeneity, as demonstrated by dodecylsulfate gel electrophoresis and analysis of the N-terminal amino acid sequence.