Beneficial effects of residual right ventricular outflow tract obstruction on right ventricular volume and function in patients after repair of tetralogy of Fallot

Preservation of the pulmonary valve, even at the expense of a mild residual stenosis, is the current surgical policy for the management of patients with tetralogy of Fallot (TOF). This study aimed to assess the long-term effect of a residual right ventricular outflow tract obstruction (RVOTO) on RV dimension and function. This study prospectively assessed 53 children (mean age, 13.4 ± 6.4 years) after repair of TOF using cardiovascular magnetic resonance imaging. Residual RVOTO on echocardiography was defined as a peak systolic RVOT gradient of 25 mmHg or higher. Patients with RVOTO (n = 29) had significantly less pulmonary regurgitation (25.2 ± 10.6 %) than patients without RVOTO (30.8 ± 9.3 %; p = 0.05) (n = 24). Compared with patients who had no RVOTO, children with RVOTO had significantly smaller RV end-diastolic volume (94.0 ± 2.6 vs 104.0 ± 20.7 ml/m(2); p < 0.05) and end-systolic volume (42.9 ± 20.0 vs 48.9 ± 13.2 ml/m(2); p < 0.05), whereas RV ejection fraction did not differ significantly between the two groups (55.5 ± 8.4 vs 54.0 ± 6.6 %). Restrictive physiology, assessed by late diastolic forward flow in the main pulmonary artery, was equally distributed within the two groups (31 vs 25 %; nonsignificant difference). According to the study data, residual RVOTO after repair of TOF does not affect RV function, whereas RV dimensions and the degree of pulmonary regurgitation are more favorable in the long-term follow-up evaluation of those patients. These results confirm the beneficial effects of the current strategy for repair of TOF.

A family of secreted pathogenesis-related proteins in Candida albicans

Analysing culture supernatants of yeast and hyphal cells of Candida albicans, we found two close homologues of pathogenesis-related (PR-) 1 proteins, Rbe1p and Rbt4p, in the secretome. Due to sequence homology, three additional, yet not characterized open reading frames, ORF19.6200, ORF19.2787 and ORF19.2336, together with RBE1 and RBT4 were assigned to a novel family of CaPRY proteins. In a Δrbe1/Δrbt4 deletion strain, genome-wide transcriptional analysis revealed differential transcription of only a limited set of genes implicated in virulence and oxidative stress response. Single deletion of RBE1 or RBT4 in a clinical C. albicans isolate resulted in a moderate but significant attenuation in virulence in a mouse model for disseminated candidiasis. However, a synergistic effect was observed in a Δrbe1/Δrbt4 double deletion strain, where virulence was strongly affected. Remarkably, transcription of RBT4 and RBE1 was each upregulated in blastospores of Δrbe1 or hyphae of Δrbt4 deletion strains respectively, indicating functional complementation thereby compensating a potential virulence defect in the single deletion strains. Furthermore, the double deletion strain showed increased sensitivity to attack by polymorphonuclear leucocytes. Therefore, the crucial contribution of both C. albicans pathogenesis-related proteins to virulence might be vested in protection against phagocyte attack.

Hepatocyte growth factor mobilizes non-bone marrow-derived circulating mesoangioblasts

AIMS

The identification of factors that mobilize subsets of endogenous progenitor cells may provide new therapeutic tools to enhance the repair of ischaemic tissue. We previously identified circulating mesenchymal cells that co-express endothelial markers (so-called circulating mesoangioblasts, cMABs) in children undergoing heart surgery with cardiopulmonary bypass (CPB). However, the mechanisms by which these cells are mobilized and their origin is unclear.

METHODS AND RESULTS

Circulating CD73(+)CD45(-)KDR(+) cMABs were analysed in adults undergoing heart surgery with (n = 21) or without CPB (n = 8). During surgery with CPB, cMABs are mobilized with a maximal response at the end of the operation. In contrast, off-pump heart surgery does not stimulate cMAB mobilization, indicating that the stress mediated by CPB induces the mobilization of cMAB. Circulating mesoangioblasts were enriched in blood obtained from the coronary sinus. Histologically, CD73(+) cells were detected around vessels in the heart, indicating that the heart is one of the niches of cMABs. Consistently, studies in gender mismatched bone marrow transplanted patients demonstrated that cMABs did not originate from the bone marrow. Cytokine profiling of serum samples revealed that hepatocyte growth factor (HGF) was profoundly increased at the time point of maximal mobilization of cMABs. Hepatocyte growth factor stimulated the migration of cMABs. Importantly, injection of recombinant HGF increased cMABs in rats.

CONCLUSIONS

Hepatocyte growth factor induces mobilization of non-haematopoietic progenitor cells with a cardiac repair capacity. This newly identified function together with the known pleiotrophic effects of HGF makes HGF an attractive therapeutic option for the treatment of ischaemic heart disease.

Sox2 transduction enhances cardiovascular repair capacity of blood-derived mesoangioblasts

RATIONALE

Complementation of pluripotency genes may improve adult stem cell functions.

OBJECTIVES

Here we show that clonally expandable, telomerase expressing progenitor cells can be isolated from peripheral blood of children. The surface marker profile of the clonally expanded cells is distinct from hematopoietic or mesenchymal stromal cells, and resembles that of embryonic multipotent mesoangioblasts. Cell numbers and proliferative capacity correlated with donor age. Isolated circulating mesoangioblasts (cMABs) express the pluripotency markers Klf4, c-Myc, as well as low levels of Oct3/4, but lack Sox2. Therefore, we tested whether overexpression of Sox2 enhances pluripotency and facilitates differentiation of cMABs in cardiovascular lineages.

METHODS AND RESULTS

Lentiviral transduction of Sox2 (Sox-MABs) enhanced the capacity of cMABs to differentiate into endothelial cells and cardiomyocytes in vitro. Furthermore, the number of smooth muscle actin positive cells was higher in Sox-MABs. In addition, pluripotency of Sox-MABs was shown by demonstrating the generation of endodermal and ectodermal progenies. To test whether Sox-MABs may exhibit improved therapeutic potential, we injected Sox-MABs into nude mice after acute myocardial infarction. Four weeks after cell therapy with Sox-MABs, cardiac function was significantly improved compared to mice treated with control cMABs. Furthermore, cell therapy with Sox-MABs resulted in increased number of differentiated cardiomyocytes, endothelial cells, and smooth muscle cells in vivo.

CONCLUSIONS

The complementation of Sox2 in Oct3/4-, Klf4-, and c-Myc-expressing cMABs enhanced the differentiation into all 3 cardiovascular lineages and improved the functional recovery after acute myocardial infarction.

A regenerative strategy for heart failure in hypoplastic left heart syndrome: intracoronary administration of autologous bone marrow-derived progenitor cells

Novel surgical strategies have dramatically improved the initial outcome of newborns with hypoplastic left heart syndrome. However, the single systemic right ventricle remains a major challenge, with limited effectiveness of pharmacologic therapy. The present case documents that the intracoronary administration of autologous bone marrow-derived progenitor cells is technically feasible in a critically ill infant with hypoplastic left heart syndrome and severe heart failure after a hybrid comprehensive stage II procedure. Cell therapy might represent an option before heart transplantation in children with single ventricle physiology presenting with severe heart failure.

Intracoronary administration of autologous bone marrow-derived progenitor cells in a critically ill two-yr-old child with dilated cardiomyopathy

DCM is the most common cardiomyopathy in childhood. Effectiveness of anticongestive therapy is limited in most cases and about one-third of children diagnosed with DCM die or receive heart transplantation within the first year after diagnosis. Cardiac stem cell transplantation has become a promising therapy to treat heart failure in adult patients. Based on these promising results, the cardiac stem cell therapy might also represent a new therapeutic option particularly in young children. The present case documents for the first time intracoronary administration of autologous bone marrow-derived progenitor cells in a critically ill two-yr-old child with severe heart failure caused by DCM. Because of progressive worsening of the clinical condition despite maximal anticongestive treatment, the decision to perform autologous stem cell therapy was made. Cardiac stem cell therapy proved to be technically feasible, was associated with improvement in cardiac function, and might represent an option before heart transplantation in children with severe heart failure.

[Involuntary patient admission and treatment against patient's will by emergency physicians]

INTRODUCTION

The treatment of acutely ill patients who presumably lack the insight or judgement to determine their need for medical treatment, is a difficult challenge for emergency physicians. We have carried out a study to assess the frequency and relevance of involuntary treatment and procedures in medical emergency services.

METHODS

Retrospective chart analysis for a 1-year period was performed for all treatment protocols of a medical emergency service unit and for all court-ordered treatments of a guardianship court. Cases of involuntary treatment by emergency physicians were identified and analysed.

RESULTS

In 10.4% of all emergency calls analysed a relevant and acute psychiatric condition was found. In 0.3% of the cases or 4.8% of the psychiatric cases, involuntary inpatient commitment was chosen by the emergency physician.

DISCUSSION

Involuntary inpatient commitment by emergency physicians was only necessary in relatively few cases. Nevertheless, in order to be able to correctly consider treatment and management options, emergency physicians should be aware of the basic conditions for treatment without a patient's consent.

Implantation of stents to ensure an adequate interatrial communication in patients with hypoplastic left heart syndrome

AIMS

To assess the feasibility of interatrial stenting for left atrial decompression in infants with hypoplastic left heart syndrome treated by a "hybrid-approach", with bilateral surgical banding of the pulmonary arteries and percutaneous stenting of the arterial duct.

PATIENTS AND METHODS

We stented the atrial septum in 5 infants aged from 21 to 77 days, making the intervention as an elective procedure in 4, but as a rescue procedure in the fifth patient, who had a restrictive foramen. The stents, comprising 2 Jo-stents of 17 millimetres hand-crimped on a balloon catheter with dimensions of 10 by 20 millimetres, and 3 premounted Genesis stents with dimensions of 10 by 19 millimetres, were placed using a 6 French long or short sheath by femoral venous access. The stents were expanded under fluoroscopic guidance to create a slightly diabolo-shaped form that fitted the septum.

RESULTS

The percutaneous interventions were successfully performed in all cases, producing significant improvement in clinical condition after placement. The saturations of oxygen increased from an average of 64% plus or minus 18% to 88% plus or minus 7%, (p < 0.05). During a mean follow up of 2.5 months, without any anticoagulant therapy, there were no complications related to the stenting. Surgical removal of the stents was uneventful during reconstruction of the aortic arch and creation of a bidirectional cavopulmonary connection in 4 patients, and during cardiac transplantation in one.

CONCLUSION

In the context of the hybrid approach, definitive decompression of the left atrium can be achieved by stenting the atrial septum in infants with hypoplastic left heart syndrome. Placement of the stents is safe and effective, with insertion in the form of a diabolo reducing the risk of dislocation, as well as embolisation of the stent.

New Inotropic Pharmacologic Strategies Targeting the Failing Myocardiumin the Newborn and Infant

Pharmacologic support of the failing neonatal heart to maintain cardiac output, which is vital for sufficient end organ perfusion, is a challenging task for the pediatric intensivist, especially since strategies which have been proven to be effective in adults cannot necessarily be extrapolated to neonates. The unique biochemical properties and structure of the neonatal heart, including the increased non-contractile tissue mass, a lower responsiveness to beta adrenergic agents and the heart rate dependent cardiac output with a limited ability to increase stroke volume, favor some of the new inotropes of the Ca+ sensitizer family. Focusing on the after load reduction, inodilators as phosphodiesterase inhibitors and human brain natriuretic peptide offer treatment options for the neonatal myocardium. Additionally, thyroxine and steroids have been investigated in neonates with low cardiac output after surgery for congenital heart disease. Gene therapy, in particular cardiac-selective gene transfer, might offer perspectives for future support for the neonatal heart. This text reviews some of the most recent pharmacologic strategies targeting the failing myocardium in the critically ill newborn and infant.

Arthroscopic treatment of chronically painful calcifying tendinitis of the supraspinatus tendon

PURPOSE

The purpose of this study was to analyze the outcome of arthroscopic removal of calcifying tendinitis of the rotator cuff, to document the postoperative pain evolution, and to analyze structural changes of the supraspinatus tendon by use of ultrasonography.

METHODS

Fifty-four of 58 patients with a mean age of 45.4 years (+/-8 years) enrolled in the study were available for follow-up. The calcific deposits were exclusively located in the supraspinatus tendon. Shoulder function was evaluated by using the Constant score. Radiographs were obtained preoperatively, immediately postoperatively, and at 3, 6, 12, and 24 months. The integrity of the rotator cuff was assessed by using ultrasonography.

RESULTS

Shoulder function according to the Constant score improved from 32.8 points (+/-19.8) preoperatively to 90.9 (+/-13.0) at 24 months (P < 0.001). The evolution of postoperative pain was very irregular; 31% of the patients were pain free or reached their minimum pain level after 3 months, 17% after 6 months, 20% after 9 months, and 28% after 12 months; 78% of the patients returned to work within 6 weeks, irrespective of their profession. At the final follow-up 92% of the patients were very satisfied with the outcome. Ultrasonography revealed minor structural changes of the supraspinatus tendon in 66% of the patients.

CONCLUSIONS

The study confirmed previously reported successful results of arthroscopic treatment of calcifying tendinitis of the rotator cuff. Complete intraoperative removal of the deposit did not appear to be essential. Even if most of the patients were able to return to work within 6 weeks, postoperative recovery was prolonged over several months in most of the patients. The clinical relevance of the ultrasonographic changes of the supraspinatus tendon has not yet been determined.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Posttraumatic anterior-inferior instability of the shoulder: arthroscopic findings and clinical correlations

INTRODUCTION

The main purpose of our study was to evaluate intra-articular lesions in glenohumeral-instability with arthroscopy and correlate them with clinical findings as well as history of instability.

MATERIAL AND METHODS

In this prospective multi-centre study, we evaluated arthroscopic findings in 303 patients with posttraumatic anterior-inferior instability of the shoulder. The study cohort was divided into 2 groups: patients with a history of one dislocation (Group 1, n=61, 20.1%) and patients with a history of more than one dislocation (Group 2, n=242, 79.9%).

RESULTS

In Group 1, 37 patients had an IGHL-lesion, 31 a MGHL-lesion and 41 a Hill-Sachs lesion. In Group 2, 182 patients had an IGHL-lesion, 172 a MGHL-lesion and 203 a Hill-Sachs lesion. The percentage of lesions in Group 2 (IGHL-75.2%, MGHL-71.1%, Hill-Sachs-83.9%) was significantly higher than in Group 1 (IGHL-60.7%, MGHL-50.8%, Hill-Sachs-67.2%, P=0.0233, P=0.0026, and P=0.0033, respectively). Within Group 2 we found significantly more Hill-Sachs-lesions with a history of an increasing number of recurrences (P=0.0436). We also found an increase of IGHL- and MGHL-lesions with an increasing number of recurrences, but this difference was not significant. The distribution of lesion types of the anterior labrum-ligament complex showed no significant difference between the two groups, apart from a higher incidence of ALPSA-lesions within Group 2 (34.7% versus 18.0% in Group 1). The results of this study show that recurrences after primary posttraumatic anterior-inferior shoulder dislocation cause increasing ligamental damage as well as increasing Hill-Sachs lesions within the gleno-humeral joint.

CONCLUSION

Thus we conclude that early surgical stabilization after posttraumatic anterior-inferior shoulder dislocation is necessary to prevent increasing damage within the shoulder joint.

Identification and characterization of Cor33p, a novel protein implicated in tolerance towards oxidative stress in Candida albicans

We applied two-dimensional gel electrophoresis to identify downstream effectors of CPH1 and EFG1 under hypha-inducing conditions in Candida albicans. Among the proteins that were expressed in wild-type cells but were strongly downregulated in a cph1Delta/efg1Delta double mutant in alpha-minimal essential medium at 37 degrees C, we could identify not-yet-characterized proteins, including Cor33-1p and Cor33-2p. The two proteins are almost identical (97% identity) and represent products of allelic isoforms of the same gene. Cor33p is highly similar to Cip1p from Candida sp. but lacks any significant homology to proteins from Saccharomyces cerevisiae. Strikingly, both proteins share homology with phenylcoumaran benzylic ether reductases and isoflavone reductases from plants. For other hypha-inducing media, like yeast-peptone-dextrose (YPD) plus serum at 37 degrees C, we could not detect any transcription for COR33 in wild-type cells, indicating that Cor33p is not hypha specific. In contrast, we found a strong induction for COR33 when cells were treated with 5 mM hydrogen peroxide. However, under oxidative conditions, transcription of COR33 was not dependent on EFG1, indicating that other regulatory factors are involved. In fact, upregulation depends on CAP1 at least, as transcript levels were clearly reduced in a Deltacap1 mutant strain under oxidative conditions. Unlike in wild-type cells, transcription of COR33 in a tsa1Delta mutant can be induced by treatment with 0.1 mM hydrogen peroxide. This suggests a functional link between COR33 and thiol-specific antioxidant-like proteins that are important in the oxidative-stress response in yeasts. Concordantly, cor33Delta deletion mutants show retarded growth on YPD plates supplemented with hydrogen peroxide, indicating that COR33 in general is implicated in conferring tolerance toward oxidative stress on Candida albicans.

Partial release of the superficial medial collateral ligament for open-wedge high tibial osteotomy. A human cadaver study evaluating medial joint opening by stress radiography

To perform an open-wedge high-tibial osteotomy (HTO), the medial proximal tibia is frequently exposed by partial distal release of the overlying insertion of the medial collateral ligament (MCL). Biomechanically, any release of the MCL can increase knee laxity when valgus stress is applied. Clinically however, post-surgical valgus instability following HTO with partial MCL release is an uncommon complication. It is known that the open-wedge procedure can re-tention an intact MCL by the width of the base of the wedge. However, this re-tentioning effect is uncertain in small wedge sizes, preexisting medial compartment laxity and in the presence of a partially detached MCL. Considering the good clinical results after HTO, we hypothesized that a partial release of the superficial MCL for HTO does not play a crucial role in stabilizing valgus forces in the human knee. We therefore measured the effect of partial versus complete release of the superficial MCL to determine medial knee laxity represented by the amount of medial joint opening (MJO) under valgus stress in this human cadaver study. In ten knee pairs, the superficial and deep MCL were sectioned in sequence with a standardized abduction force of 15 kp with a Scheuba apparatus applied. In group 1 (5 knee pairs), the superficial MCL was completely sectioned whereas in group 2 (5 knee pairs), sectioning of the superficial MCL was restricted to the anterior border to mimic the surgical exposure for an HTO. To account for the interindividual variability of ligamentous laxity, only increments of MJO within knee pairs were statistically evaluated. Stress radiography did not reveal any significant differences in increments of MJO between knee pair specimens with complete versus partial release of the superficial MCL. We disproved our hypothesis and concluded that the anterior fibers of the superficial MCL do play a crucial role in maintaining valgus stability in this biomechanical setting. Therefore, the release of the superficial MCL for open-wedge HTO should be kept to a minimum to decrease the potential of late valgus instability. This is especially important in patients with small wedge sizes and medial compartment laxity since the anterior MCL fibers are the main contributor to medial joint stability and the re-tentioning effect of the remaining MCL fibers is presumably decreased.

Differentiation of circulating endothelial progenitor cells to a cardiomyogenic phenotype depends on E-cadherin

Progenitor cells may contribute to cardiac regeneration. Here, we investigated the role of cadherins and integrins for differentiation of human adult circulating endothelial progenitor cells (EPCs) into cardiomyocytes (CM) in a co-culture system. N- and E-cadherin were expressed in EPCs and were localized at the interface between EPCs and CM. Incubation of a blocking antibody against E-cadherin reduced the expression of CM marker protein in EPCs. Blocking antibodies against N- or P-cadherin or the beta1- and beta2-integrins were not effective. These data suggested that cell-to-cell communication mediated by E-cadherin contributes to the acquirement of a cardiomyogenic phenotype of human endothelial progenitor cells.

Primary stability of various forms of osteosynthesis in the treatment of fractures of the proximal tibia

The treatment of fractures of the proximal tibia is complex and makes great demands on the implants used. Our study aimed to identify what levels of primary stability could be achieved with various forms of osteosynthesis in the treatment of diaphyseal fractures of the proximal tibia. Pairs of human tibiae were investigated. An unstable fracture was simulated by creating a defect at the metaphyseal-diaphyseal junction. Six implants were tested in a uniaxial testing device (Instron) using the quasi-static and displacement-controlled modes and the force-displacement curve was recorded. The movements of each fragment and of the implant were recorded video-optically (MacReflex, Qualysis). Axial deviations were evaluated at 300 N.

The results show that the nailing systems tolerated the highest forces. The lowest axial deviations in varus and valgus were also found for the nailing systems; the highest axial deviations were recorded for the buttress plate and the less invasive stabilising system (LISS). In terms of rotational displacement the LISS was better than the buttress plate.

In summary, it was found that higher loads were better tolerated by centrally placed load carriers than by eccentrically placed ones. In the case of the latter, it appears advantageous to use additive procedures for medial buttressing in the early phase.

Ultrasonographic evaluation at 6-month follow-up of plantar fasciitis after extracorporeal shock wave therapy

INTRODUCTION

The aim of this study was to investigate the effect of extracorporeal shock wave therapy (ESWT) on the ultrasonographic appearance of chronically painful, proximal plantar fasciitis.

MATERIALS AND METHODS

Twenty-two patients with a unilateral proximal plantar fasciitis were prospectively enrolled after unsuccessful conservative treatment lasting 6 months. The contralateral plantar fascia was used as the control. ESWT (3x3000 shock waves/session of 0.2 mJ/mm2) was performed at weekly intervals. The thickness of the plantar fascia was measured ultrasonographically about 2 cm distal of the medial calcaneal tuberosity. Pain estimation on a visual analogue scale (VAS) and the comfortable walking time were recorded. No local anaesthesia was applied. Follow-up was done at 6, 12 and 24 weeks.

RESULTS

Before ESWT, the plantar fasciitis side was ultrasonographically significantly thicker than the control side (p<0.05), whereas 6 months after ESWT, the thickness of the fascia was no longer significantly different. The decrease in thickness of the plantar fasciitis side was significant (p<0.05). Pain during activities of daily living decreased by 79% according to the VAS, and the comfortable walking time increased, both significantly (p<0.01). In patients with little pain (VAS<30), the thickness of the plantar fasciitis side was significantly less (p<0.01) compared with patients who still suffered more pain (VAS>30).

CONCLUSION

After ESWT, the thickness of the plantar fascia in patients with plantar fasciitis decreased, pain and walking time improved (all significantly).

[Stability, bone healing and loss of correction after valgus realignment of the tibial head. A roentgen stereometry analysis]

In high tibial closing-wedge osteotomies (HTO), closure of an osteotomy gap after resection of a bony wedge can be associated with a fissure of the medial cortex of the tibial head (MCT). The effect of a broken MCT on the recurrence of varus deformity is disputed. In this study, serial roentgen stereometric analysis (RSA) was used to determine the fixation stability of a rigid internal "L" plate after HTO. Full weight lower limb radiographs were used to determine the sagittal alignment in patients with varying degrees of varus malalignment and correction over time. Forty-two patients with varus gonarthrosis stage I-III (Ahlback) were treated with HTO and internal fixation with an L-shaped rigid plate. Patients were followed by serial RSA, conventional radiographs, and clinical evaluation (Hospital of Special Surgery score) over a 12-month period. In 19 of 42 successive patients, an average wedge size of 6.9 degrees was resected leaving the MCT intact (group 1). In 23 of 42 of patients, the MCT was unintentionally fissured during surgery when an average 10.3 degrees -wedge was resected (group 2). In group 2, RSA revealed a fivefold increase in lateral displacement of the distal tibial segment within 3 weeks after HTO. Twelve weeks after HTO, translations between tibial segments were below the accuracy of the RSA setup in the majority of patients. Group 1 patients demonstrated a higher initial fixation stability, less occurrence of varus deformity, and a higher HSS score compared to patients with larger wedge sizes and frequent fracture of the MCT (group 2). Before bone healing is achieved, the integrity of the MCT plays a crucial role for the clinical and radiological outcome after HTO.

[Imaging and preoperative planning of osteotomy of tibial head osteotomy]

Valgus-producing osteotomy of the proximal tibia is a well-established treatment for medial femorotibial osteoarthritis in the varus knee. The ideal patient is active, under 55 years of age, has a stable varus deformity of less than 10 degrees, a good bone stock, and an osteoarthritis stage that is restricted to the medial compartment of the knee. Coventry reported a failure rate in proximal tibial osteotomy to be significantly higher when the postoperative alignment was less than 8 degrees of anatomical valgus. Hernigou noted better clinical long-term results in cases with a precise correction of malalignment. There are different preoperative planning methods varying between simple estimates of correction angles and specific radiographic planning tools. The reproducibility of operative outcome with regard to a predictable anatomic alignment and functional recovery must have high priority. This chapter deals with different preoperative planning methods to improve the reliability of surgical results after tibial osteotomy.

Biomechanical properties of patellar and hamstring graft tibial fixation techniques in anterior cruciate ligament reconstruction: experimental study with roentgen stereometric analysis

BACKGROUND

Reliable fixation of the soft hamstring grafts in ACL reconstruction has been reported as problematic.

HYPOTHESIS

The biomechanical properties of patellar tendon (PT) grafts fixed with biodegradable screws (PTBS) are superior compared to quadrupled hamstring grafts fixed with BioScrew (HBS) or Suture-Disc fixation (HSD).

STUDY DESIGN

Controlled laboratory study with roentgen stereometric analysis (RSA).

METHODS

Ten porcine specimens were prepared for each group. In the PT group, the bone plugs were fixed with a 7 x 25 mm BioScrew. In the hamstring group, four-stranded tendon grafts were anchored within a tibial tunnel of 8 mm diameter either with a 7 x 25 mm BioScrew or eight polyester sutures knotted over a Suture-Disc. The grafts were loaded stepwise, and micromotion of the graft inside the tibial tunnel was measured with RSA.

RESULTS

Hamstring grafts failed at lower loads (HBS: 536 N, HSD 445 N) than the PTBS grafts (658 N). Stiffness in the PTBS group was much greater compared to the hamstring groups (3500 N/mm versus HBS = 517 N/mm and HSD = 111 N/mm). Irreversible graft motion after graft loading with 200 N was measured at 0.03 mm (PTBS), 0.38mm (HBS), and 1.85mm (HSD). Elasticity for the HSD fixation was measured at 0.67 mm at 100 N and 1.32 mm at 200 N load.

CONCLUSION

Hamstring graft fixation with BioScrew and Suture-Disc displayed less stiffness and early graft motion compared to PTBS fixation. Screw fixation of tendon grafts is superior to Suture-Disc fixation with linkage material since it offers greater stiffness and less graft motion inside the tibial tunnel.

CLINICAL RELEVANCE

Our results revealed graft motion for hamstring fixation with screw or linkage material at loads that occur during rehabilitation. This, in turn, may lead to graft laxity.

Statin therapy in patients with coronary artery disease improves the impaired endothelial progenitor cell differentiation into cardiomyogenic cells

Human endothelial progenitor cells (EPCs) can differentiate into cardiomyogenic cells in vitro. We tested the effects of statin therapy on the differentiation rate of EPCs from patients with coronary artery disease (CAD), who may benefit from autologous cell therapy.EPCs from 3 age-matched groups were tested: No CAD (n = 13), CAD patients with (n = 10) or without (n = 16) statin therapy. From 4 CAD patients, EPCs were tested before and after 4 weeks of therapy with 20 mg atorvastatin. After 6 days of co-culture with rat neonatal cardiomyocytes, EPC differentiation was quantified by immunostaining for alpha-sarcomeric actinin flow cytometry analysis. After 6 days of co-culture, the percentage of -sarcomeric actinin-positive EPCs was significantly (p = 0.014) higher in EPCs from adults without CAD (8.07% +/- 1.48% of EPCs) compared to EPCs from CAD patients without statin (3.56% +/- 0.72%). Importantly, patients with statin therapy revealed significantly higher numbers of alpha-sarcomeric actinin-positive EPCs (6.36% +/- 0.69%, p = 0.01) compared to CAD patients without statin. In addition, statin therapy resulted in a significant (p = 0.017) increase of EPC differentiation in all 4 CAD patients investigated before and 4 weeks after statin therapy. The survival of EPCs did not differ between the different groups suggesting that the regulation of EPC differentiation is not secondary to altered EPC survival. In vitro, EPC treatment with 0.1 micro M atorvastatin did not affect EPC differentiation (116.15% +/- 49.11% of control).EPCs from patients with CAD display impaired differentiation into cardiomyogenic cells. This defect can be improved by in vivo, statin therapy.

[Arthroscopic elbow surgery in rheumatoid arthritis]

The technique of arthroscopic elbow surgery and its possibilities in the rheumatoid arthritic elbow is discussed. Emphasis is placed on the description of arthroscopic anterior (anterolateral, anteromedial, superomedial) and posterior approaches (straight lateral, posterolateral, straight posterior) to the elbow and the surrounding neurovascular anatomy. Technical hints for elbow arthroscopy especially with relevance to the rheumatoid population are given.

Identification of cell surface determinants in Candida albicans reveals Tsa1p, a protein differentially localized in the cell

To identify cell surface proteins of Candida albicans, the predominant fungal pathogen in humans, we have established an approach using a membrane impermeable biotin derivative in combination with affinity purification. We were able to identify 29 different proteins under two distinct conditions. Among mannoproteins, heat shock proteins and glycolytic enzymes we found thiol-specific antioxidant-like protein 1 (Tsa1p) to be differentially localized depending on the conditions applied. Only in hyphally grown cells Tsa1p was localized to the cell surface whereas in blastospores no surface but mainly nuclear localization was found. This indicates that cell surface expression of at least some proteins is mediated by differential translocation.

Transdifferentiation of blood-derived human adult endothelial progenitor cells into functionally active cardiomyocytes

BACKGROUND

Further to promoting angiogenesis, cell therapy may be an approach for cardiac regeneration. Recent studies suggest that progenitor cells can transdifferentiate into other lineages. However, the transdifferentiation potential of endothelial progenitor cells (EPCs) is unknown.

METHODS AND RESULTS

EPCs were obtained from peripheral blood mononuclear cells of healthy adults or coronary artery disease (CAD) patients by cultivating with endothelial cell medium and growth factors. After 3 days, >95% of adherent cells were functionally and phenotypically EPCs. Diacetylated LDL-labeled EPCs were then cocultivated with rat cardiomyocytes for 6 days, resulting in significant increases of EPC cell length and size to a cardiomyocyte-like morphology. Biochemically, 9.94+/-1.39% and 5.04+/-1.09% of EPCs from healthy adults (n=15) or CAD patients (n=14, P<0.01 versus healthy adults), respectively, expressed alpha-sarcomeric actinin as measured by flow cytometry. Immunocytochemistry showed that human EPCs expressed alpha-sarcomeric actinin, cardiac troponin I (both with partial sarcomeric organization), atrial natriuretic peptide, and myocyte enhancer factor 2. Fluo 4 imaging demonstrated calcium transients synchronized with adjacent rat cardiomyocytes in transdifferentiated human EPCs. Single-cell microinjection of Lucifer yellow and calcein-AM labeling of cardiomyocytes demonstrated gap junctional communication between 51+/-7% of EPCs (16 hours after labeling, n=4) and cardiomyocytes. EPC transdifferentiation into cardiomyocytes was not observed with conditioned medium but in coculture with paraformaldehyde-fixed cardiomyocytes.

CONCLUSIONS

EPCs from healthy volunteers and CAD patients can transdifferentiate in vitro into functionally active cardiomyocytes when cocultivated with rat cardiomyocytes. Cell-to-cell contact but not cellular fusion mediates EPC transdifferentiation. The therapeutic use of autologous EPCs may aid cardiomyocyte regeneration in patients with ischemic heart disease.

A screen in Saccharomyces cerevisiae identified CaMCM1, an essential gene in Candida albicans crucial for morphogenesis

Morphogenesis in Saccharomyces cerevisiae and the pathogenic yeast Candida albicans is governed in part by the same molecular circuits. In S. cerevisiae, FLO11/MUC1 expression has been shown to be modulated by multiple signalling pathways required for pseudohyphal development. We have established a screen in S. cerevisiae to identify regulators of fungal development in C. albicans based on FLO11::lacZ expression as a reporter. This screen identified both known components of the mitogen-activated protein kinase (MAPK) cascade and the cAMP cascade that are important for hyphal development in C. albicans, as well as genes not yet known to be involved in morphogenesis. The Candida homologue of MCM1 is one of the novel factors identified in this screen as being important for morphogenesis. CaMcm1p levels do not vary significantly in different cell types and respond to an autoregulatory feedback mechanism, arguing that CaMcm1p activity is regulated by post-translational modifications. Both overexpression and repression of this essential gene led to the induction of hyphae. Moreover, we found that the expression of HWP1, a hyphae-specific gene, was induced by repression of CaMCM1. The changes in morphology and HWP1 expression were not the result of a change in expression levels of NRG1 or TUP1, known repressors of hyphal development. Thus, CaMcm1p is a component of a hitherto unknown regulatory mechanism of hyphal growth.

[Biodegradable meniscus fixations: a comparative biomechanical study]

PURPOSE

Numerous new all inside meniscus repair techniques using biodegradable fixation devices have become available in the last years. Few studies have dealt with the biomechanical properties of these implants so far. The aim of this study was to analyze meniscus repairs under cyclic loading conditions for different fixation devices (Meniscus Arrow, Clearfix Meniscal Screw, Meniscal Dart, BioStinger) and to compare them to standard suture techniques.

MATERIAL AND METHODS

Eighty meniscus repairs on 27 medial porcine menisci were performed. For biomechanical testing loosening, number of failures, failure modes and failure loads were evaluated under cyclic and maximum loading conditions. Testing was performed on a materials testing machine.

RESULTS

During cyclic loading 10 out of 40 (25%) fixation devices failed. A gap appeared between the 2 parts of the meniscus within the first loading cycles. The failure strengths obtained with the 4 meniscus fixation devices did not differ significantly (Meniscus Arrow: 44 N; Clearfix Meniscal Screw: 35 N; Meniscal Dart: 33 N; BioStinger: 54 N). Besides for the BioStinger, the values of the sutures were significantly higher. The use of a stronger suture material (PDS 0) increased the failure load significantly. During maximum loading the fixation devices failed by both pull-out of the head or the tip of the device, except for the BioStinger showing only pull-out of the head. All sutures failed by breakage, except for the PDS 0 horizontal sutures in which 50% of complete tissue failures could be noted.

CONCLUSION

This study shows that meniscal fixation devices may fail under repetitive loading conditions. A gap appeared between the meniscal margins within the first loading cycles irrespective of the suture type and fixation device used. Both gapping and failure modes of the fixation devices may be design-specific. The maximum failure loads differed significantly between the bioabsorbable devices and the sutures. Stronger suture materials increased the failure loads significantly. To allow a complete evaluation of new meniscus fixation devices not only biomechanical, but also biological and clinical parameters need to be analyzed in forthcoming studies.

EFG1 is a major regulator of cell wall dynamics in Candida albicans as revealed by DNA microarrays

Cell wall dynamics in Candida albicans, the most common fungal pathogen in man, underlie regulatory processes during the yeast-to-hyphae transition. To analyse this regulation at the transcriptional level, we have established a DNA microarray representing genes implicated in cell wall biogenesis. Using these microarrays, we were able to identify YWP1 and HWP2 that are specifically transcribed in the yeast or hyphal growth form respectively. Cluster analysis revealed at least two major clusters of genes: cluster I comprised genes that were upregulated under at least one hyphae-inducing condition. Three as yet not further characterized genes were attributed to cluster II. These genes were transcribed in the yeast form of C. albicans and were downregulated in an EFG1-dependent manner under specific hyphae-inducing conditions. We show further that, in contrast to CPH1, EFG1 plays a major role in the transcriptional regulation of cell wall proteins under the conditions investigated. EFG1 was essential for the transcription of both hyphae-specific genes such as HWP1 and HWP2 as well as the yeast form-specific gene YWP1. Moreover, we found that, under various conditions, EFG1 also can act as a strong repressor for the transcription of RBE1, another not yet characterized cell wall protein. Overall, our data show that EFG1 plays a major role in the induction and repression of cell wall genes, not only in the hyphal form but also in the yeast form of C. albicans.