New skin substitutes for burn medicine or reconstructive surgery pose an important issue in plastic surgery. Matriderm® is a clinically approved three-dimensional bovine collagen-elastin matrix which is already used as a dermal substitute of full thickness burn wounds. The drawback of an avital matrix is the limited integration in full thickness skin defects, depending on the defect size. To further optimize this process, Matriderm® has also been studied as a matrix for tissue engineering of skin albeit long-term cultivation of the matrix with cells has been difficult. Cells have generally been seeded onto the matrix with high cell loss and minimal time-consuming migration. Here we developed a cell seeded skin equivalent after microtransfer of cells directly into the matrix. First, cells were cultured, and microinjected into Matriderm®. Then, cell viability in the matrix was determined by histology in vitro. As a next step, the skin substitute was applied in vivo into a full thickness rodent wound model. The wound coverage and healing was observed over a period of two weeks followed by histological examination assessing cell viability, proliferation and integration into the host. Viable and proliferating cells could be found throughout the entire matrix. The presented skin substitute resembles healthy skin in morphology and integrity. Based on this study, future investigations are planned to examine behaviour of epidermal stem cells injected into a collagen-elastin matrix under the aspects of establishment of stem cell niches and differentiation.
skin substitute; elastin-collagen bovine matrix; Matriderm®; epidermal stem cells; fibroblasts; keratinocytes
Introduction: Tamoxifen is associated with a twofold increased risk of thromboembolic events. Third generation aromatase inhibitors (AIs), such as letrozole, anastrozole, and exemestane have therefore replaced tamoxifen in the adjuvant therapy of hormone receptor-positive breast cancer. A retrospective review was performed in patients who underwent delayed microvascular breast reconstruction and received tamoxifen at the time of surgery in order to assess the risk of both minor and major flap complications including thromboembolic events.
Patients and methods: Twenty-nine patients who underwent delayed microsurgical breast reconstruction with autologous tissue between 2006 and 2012 were included in the study. The overall complication rates were compared between patients who did versus those who did not receive tamoxifen at the time of microsurgical breast reconstruction.
Results: Breast reconstruction was performed with a DIEP flap in 25 patients and with a TRAM flap in 4 patients. Overall, the complication rate was 37.9% (n=11) consisting of 5 major (including one total flap loss) and 6 minor complications. In patients receiving tamoxifen (n=5), we observed one minor complication and one major complication with a total flap loss due to thrombus formation at the anastomosis site. In one patient pulmonary embolism occurred without association to tamoxifen. The number of thromboembolic events was equivalent in both groups (p=0.642). No increase of major (p=0.858) or minor (p=0.967) complications in the tamoxifen group could be observed. Taking the overall complication rate into account there was no statistically difference between the two groups (p=0.917).
Conclusion: In our study we could not observe an increased risk for thromobembolic events in patients receiving tamoxifen while undergoing autologous microvascular breast reconstruction.
Tamoxifen; breast cancer; adjuvant therapy; microvascular breast reconstruction
Tendinopathy of the flexor carpi ulnaris tendon is a rare entity. Recent research revealed the role of a neurovascular ingrowth at the point of pain in various tendinopathic locations, such as at the Achilles and patellar tendon, in plantar fasciitis as well as in supraspinatus and tennis elbow tendinopathy. However, beyond the elbow no such neovascularisation has been reported to date.
We present a 35‐year old tennis player suffering tremendous pain (visual analogue scale (VAS) rating of 9/10) at the flexor carpi ulnaris tendon with adjacent calcification in close proximity to the pisiform bone. The patient was assessed with power Doppler and laser Doppler quantification of neovascularisation at the point of pain.
Power Doppler and laser Doppler quantification of neovascularisation at the point of pain identified higher capillary blood flow at three points over the painful vs the non‐painful tendon (146/240/232rU vs 93/74/70rU at the non‐affected side). Sclerosing therapy using polidocanol under power and laser Doppler guidance was initiated, with immediate decrease of capillary blood flow by 25% with resolution of the neovascularisation in power Doppler. Immediately following sclerosing, the patient's reported pain level on the VAS was reduced from 9/10 to 4/10. Following a short period of rest, eccentric training of the forearm muscle was initiated over 12 weeks with functional complete recovery and complete resolution of wrist pain.
Sclerosing therapy using polidocanol under power‐ and laser‐Doppler guidance can decrease capillary blood flow by 25% with resolution of the neovascularisation. Subsequent eccentric training of the forearm muscle over 12 weeks can result in complete resolution of wrist pain.
Neovascularisation and microcirculatory changes have been reported in Achilles tendinopathy. Cryotherapy and compression, as part of a rest, ice, compression and elevation regimen, are shown to decrease pain and improve function. However, the microcirculatory changes following a given dosage of cryotherapy on mid‐portion Achilles tendon remain unclear.
Prospective clinical cohort study, level of evidence 2.
30 people (12 males, 33 (SD 12) years, body mass index 25.6 (5.3) kg/m2) were included in the cohort. 3×10 min KoldBlue ankle‐cooling bandages were applied and microcirculation of Achilles tendon mid‐portion was real‐time and continuously assessed using a laser‐Doppler‐spectrophotometry system (O2C, Germany).
Superficial capillary blood flow was reduced from 42 to 6, 5 and 3 relative units (rU) in the first, second and third cryotherapy periods, respectively (−65%, p = 0.001), with no significant capillary hyperaemia. Deep capillary tendon blood flow was reduced from 180 to 82, 53 and 52 rU (−71%, p = 0.001) within 6–9 min of application without hyperaemia. Superficial tendon oxygen saturation dropped significantly from 43% to 26%, 18% and 11% (p = 0.001) after repetitive cryotherapy, with persisting increase of tendon oxygenation during rewarming (51%, 49% and 54%, p = 0.077) up to 27% of the baseline level. At 8 mm tendon depth, cryotherapy preserved local oxygenation. Relative postcapillary venous tendon filling pressures were favourably reduced from 41 (11) to 31, 28 and 26 rU (−36%, p = 0.001) superficially and from 56 (11) to 45, 46 and 48 rU (−18%, p = 0.001) in deep capillary blood flow during cryotherapy, facilitating capillary venous clearance.
Intermittent cryotherapy of 3×10 min significantly decreases local Achilles tendon mid‐portion capillary blood flow by 71%. Within 2 min of rewarming, tendon oxygen saturation is re‐established following cryotherapy. Postcapillary venous filling pressures are reduced during cryotherapy, favouring capillary venous outflow of the healthy Achilles tendon.
We present a laminar flow reactor for bone tissue engineering that was developed based on a computational fluid dynamics model. The bioreactor design permits a laminar flow field through its specific internal shape. An integrated bypass system that prevents pressure build-up through bypass openings for pressure release allows for a constant pressure environment during the changing of permeability values that are caused by cellular growth within a porous scaffold. A macroporous ceramic scaffold, composed of zirconium dioxide, was used as a test biomaterial that studies adipose stem cell behavior within a controlled three-dimensional (3D) flow and pressure environment. The topographic structure of the material provided a basis for stem cell proliferation and differentiation toward the osteogenic lineage. Dynamic culture conditions in the bioreactor supported cell viability during long-term culture and induced cell cluster formation and extra-cellular matrix deposition within the porous scaffold, though no complete closure of the pores with new-formed tissue was observed. We postulate that our system is suitable for studying fluid shear stress effects on stem cell proliferation and differentiation toward bone formation in tissue-engineered 3D constructs.
bioreactor; bone tissue engineering; computer model; fluid dynamics; laminar flow; shear stress; 3D culture
Advanced strategies in reconstructive microsurgery and especially free tissue transfer with advanced microvascular techniques have been routinely applied and continously refined for more than three decades in day-to-day clinical work. Bearing in mind the success rates of more than 95%, the value of these techniques in patient care and comfort (one-step reconstruction of even the most complex tissue defects) cannot be underestimated.
However, anticoagulative protocols and practices are far from general acceptance and – most importantly – lack the benchmark of evidence basis while the reconstructive and microsurgical methods are mostly standardized.
Therefore, the aim of our work was to review the actual literature and synoptically lay out the mechanisms of action of the plethora of anticoagulative substances.
The pharmacologic prevention and the surgical intervention of thrombembolic events represent an established and essential part of microsurgery. The high success rates of microvascular free tissue transfer as of today are due to treatment of patients in reconstructive centers where proper patient selection, excellent microsurgical technique, tissue transfer to adequate recipient vessels, and early anastomotic revision in case of thrombosis is provided. Whether the choice of antithrombotic agents is a factor of success remains still unclear. Undoubtedly however the lack of microsurgical experience and bad technique can never be compensated by any regimen of antithrombotic therapy. All the more, the development of consistent standards and algorithms in reconstructive microsurgery is absolutely essential to optimize clinical outcomes and increase multicentric and international comparability of postoperative results and complications.
anticoagulation; microsurgery; heparin-induced thrombocytopenia (HiT); thrombosis
Strategies for improvement of nerve regeneration and optimal conditions to prevent Schwann cell (SC) loss within a nerve transplant procedure are critical. The purpose of this study was to examine SC viability, which plays an important role in peripheral nerve regeneration, under various incubation conditions up to three hours. To address this issue, Schwann cell metabolic activity was determined using different independent test methods. The following experimental conditions were compared: SCs prepared from nerves were incubated in (1) isotonic saline solution (2) Dulbecco's modified Eagles medium as used for cell culturing, (3) Hannover bioreactor medium, and (4) Leibovitz's medium. SC metabolic activity of excised rat sciatic nerve was determined at 4°C, 18°C, and 37°C over 3 hrs. The results indicate that SC activity was optimized by the usage of Leibovitz's medium or HBRM at 37°C. Greater SC viability at the time of surgical nerve grafting could contribute to improved axonal regeneration and remyelination after nerve transplantation, and thus more successful functional recovery.
Burn injury is frequently complicated by bacterial infection. Following burn injury, exposure to endotoxin produces a measurable decrease in cardiomyocyte sarcomere contractile function. Lipopolysaccharide-binding protein (LBP) is an acute phase protein that potentiates the recognition of lipopolysaccharide (LPS) by binding to the lipid A moiety of LPS. In this study we sought to determine the effect of recombinant rat LBP (rLBP) on cardiomyocyte sarcomere function after burn or sham injury in the presence or absence of bacterial endotoxin.
Rats underwent a full-thickness 30% total body surface area scald or sham burn. At 24 hours post injury, cardiomyocytes were isolated, plated at 50,000 cells/well and incubated with 50 μg/mL LPS and rLBP) or chloramphenicol acetyltransferase (BVCat, an irrelevant control protein produced using the same expression system as rLBP) at concentrations by volume of 1, 5, 10, and 30%. Subsets of cardiomyocytes were incubated with 5 % rat serum or 30% rLBP and blocking experiments were conducted using an LBP-like synthetic peptide (LBPK95A). In-vitro sarcomere function was measured using a variable rate video camera system with length detection software.
Co-culture of burn and sham injury derived cardiomyocytes with high-dose rLBP in the presence of LPS resulted in a significant reduction to the functional impairment observed in peak sarcomere shortening following exposure to LPS alone. LBP-like peptide LBPK95A at a concentration of 20 μg/mL, in the presence of LPS, abolished the ability of 30 % rLBP and 5% rat serum to restore peak sarcomere shortening of cardiomyocytes isolated following burn injury to levels of function exhibited in the absence of endotoxin exposure.
In the setting of LPS challenge following burn injury, rLBP at high concentrations restores cardiomyocyte sarcomere contractile function in vitro. Rather than potentiating the recognition of LPS by the cellular LPS receptor complex, rLBP at high concentrations likely results in an inhibitory binding effect that minimizes the impact of endotoxin exposure on cardiomyocyte function following thermal injury.
Burn trauma; Burn injury; Cardiac function; Endotoxin; Langendorff preparation; Sarcomere contraction and relaxation; Lipopolysaccharide-binding protein (LBP)
The quality of oral and poster conference presentations differ. We hypothesized that the quality of reporting is better in oral abstracts than in poster abstracts at the American Burn Association (ABA) conference meeting.
All 511 abstracts (2000: N = 259, 2008: N = 252) from the ABA annual meetings in year 2000 and 2008 were screened. RCT's and obervational studies were analyzed by two independent examiners regarding study design and quality of reporting for randomized-controlled trials (RCT) by CONSORT criteria, observational studies by the STROBE criteria and additionally the Timmer instrument.
Overall, 13 RCT's in 2000 and 9 in 2008, 77 observational studies in 2000 and 98 in 2008 were identified. Of the presented abstracts, 5% (oral; 7%(n = 9) vs. poster; 3%(n = 4)) in 2000 and 4% ((oral; 5%(n = 7) vs. poster; 2%(n = 2)) in 2008 were randomized controlled trials. The amount of observational studies as well as experimental studies accepted for presentation was not significantly different between oral and poster in both years. Reporting quality of RCT was for oral vs. poster abstracts in 2000 (CONSORT; 7.2 ± 0.8 vs. 7 ± 0, p = 0.615, CI -0.72 to 1.16, Timmer; 7.8 ± 0.7 vs. 7.5 ± 0.6,) and 2008 (CONSORT; 7.2 ± 1.4 vs. 6.5 ± 1, Timmer; 9.7 ± 1.1 vs. 9.5 ± 0.7). While in 2000, oral and poster abstracts of observational studies were not significantly different for reporting quality according to STROBE (STROBE; 8.3 ± 1.7 vs. 8.9 ± 1.6, p = 0.977, CI -37.3 to 36.3, Timmer; 8.6 ± 1.5 vs. 8.5 ± 1.4, p = 0.712, CI -0.44 to 0.64), in 2008 oral observational abstracts were significantly better than posters (STROBE score; 9.4 ± 1.9 vs. 8.5 ± 2, p = 0.005, CI 0.28 to 1.54, Timmer; 9.4 ± 1.4 vs. 8.6 ± 1.7, p = 0.013, CI 0.32 to 1.28).
Poster abstract reporting quality at the American Burn Association annual meetings in 2000 and 2008 is not necessarily inferior to oral abstracts as far as study design and reporting quality of clinical trials are concerned. The primary hypothesis has to be rejected. However, endorsement for the comprehensive use of the CONSORT and STROBE criteria might further increase the quality of reporting ABA conference abstracts in the future.
Burns; evidence; consort; strobe; timmer; reporting quality; abstract
Therapeutic strategies aiming to reduce ischemia/reperfusion injury by conditioning tissue tolerance against ischemia appear attractive not only from a scientific perspective, but also in clinics. Although previous studies indicate that remote ischemic intermittent preconditioning (RIPC) is a systemic phenomenon, only a few studies have focused on the elucidation of its mechanisms of action especially in the clinical setting. Therefore, the aim of this study is to evaluate the acute microcirculatory effects of remote ischemic preconditioning on a distinct cutaneous location at the lower extremity which is typically used as a harvesting site for free flap reconstructive surgery in a human in-vivo setting.
Microcirculatory data of 27 healthy subjects (25 males, age 24 ± 4 years, BMI 23.3) were evaluated continuously at the anterolateral aspect of the left thigh during RIPC using combined Laser-Doppler and photospectrometry (Oxygen-to-see, Lea Medizintechnik, Germany). After baseline microcirculatory measurement, remote ischemia was induced using a tourniquet on the contralateral upper arm for three cycles of 5 min.
After RIPC, tissue oxygen saturation and capillary blood flow increased up to 29% and 35% during the third reperfusion phase versus baseline measurement, respectively (both p = 0.001). Postcapillary venous filling pressure decreased statistically significant by 16% during second reperfusion phase (p = 0.028).
Remote intermittent ischemic preconditioning affects cutaneous tissue oxygen saturation, arterial capillary blood flow and postcapillary venous filling pressure at a remote cutaneous location of the lower extremity. To what extent remote preconditioning might ameliorate reperfusion injury in soft tissue trauma or free flap transplantation further clinical trials have to evaluate.
Remote ischemic preconditioning; cutaneous microcirculation; free flap; soft tissue
In the field of Plastic Reconstructive Surgery the development of new innovative matrices for skin repair is in urgent need. The ideal biomaterial should promote attachment, proliferation and growth of cells. Additionally, it should degrade in an appropriate time period without releasing harmful substances, but not exert a pathological immune response. Spider dragline silk from Nephila spp meets these demands to a large extent.
Native spider dragline silk, harvested directly out of Nephila spp spiders, was woven on steel frames. Constructs were sterilized and seeded with fibroblasts. After two weeks of cultivating single fibroblasts, keratinocytes were added to generate a bilayered skin model, consisting of dermis and epidermis equivalents. For the next three weeks, constructs in co-culture were lifted on an originally designed setup for air/liquid interface cultivation. After the culturing period, constructs were embedded in paraffin with an especially developed program for spidersilk to avoid supercontraction. Paraffin cross- sections were stained in Haematoxylin & Eosin (H&E) for microscopic analyses.
Native spider dragline silk woven on steel frames provides a suitable matrix for 3 dimensional skin cell culturing. Both fibroblasts and keratinocytes cell lines adhere to the spider silk fibres and proliferate. Guided by the spider silk fibres, they sprout into the meshes and reach confluence in at most one week. A well-balanced, bilayered cocultivation in two continuously separated strata can be achieved by serum reduction, changing the medium conditions and the cultivation period at the air/liquid interphase. Therefore spider silk appears to be a promising biomaterial for the enhancement of skin regeneration.
Lifeguard (LFG), an anti-apoptotic protein with high expression rates in breast cancer cells, has been identified as a molecule that inhibits death mediated by Fas. The molecular function of LFG and its regulation in the carcinogenesis of human breast and sarcoma cells, however, remains to be elucidated. In the present study, we investigated the ability of LFG expression to inhibit apoptosis induced by the alkyl-phospholipid perifosine. Results showed that LFG was able to be downregulated in selected sarcoma and breast cancer cell lines characterized by high endogenous LFG expression. A decreased LFG expression led to enhanced sensitivity to treatment with an agonistic Fas antibody or treatment with perifosine. Taken together, our findings indicate the role of LFG as an anti-apoptotic protein and provide further evidence of the potential of LFG as a target for the development of novel therapeutic strategies.
apoptosis; lifeguard; Fas; perifosine; cancer
Cellulite is a widespread problem involving females' buttocks and thighs based on the female specific anatomy. Given the higher number of fat cells stored in female fatty tissue in contrast to males, and the aging process of connective tissue leads to an imbalance between lipogenesis and lipolysis with subsequent large fat cells bulging the skin. In addition, microcirculatory changes have been suggested, however remain largely unknown in a controlled clinical setting. We hypothesize that the combination of extracorporeal shockwave and a daily gluteal muscle strength program is superior to the gluteal muscle strength program alone in cellulite.
Study design: Randomized-controlled trial. IRB approval was granted at Hannover Medical School, Germany on May 22, 2009. For allocation of participants, a 1:1 ratio randomization was performed using opaque envelopes for the concealment of allocation. Reporting: according to CONSORT 2010. Eligible patients were females aged 18 or over and 65 or younger with cellulite with documented cellulite 1°-4° according to the Nürnberger score. Exclusion criteria were suspected or evident pregnancy, no cellulite, no informed consent or age under 18 years or above 65 years. Patients were recruited by advertisements in local regional newspapers and via the Internet. Analysis: Intention-to-treat. Outcome parameters: a) Photonumeric severity scale, b) Nürnberger Score, c) circumference measurements, d) capillary blood flow, e) tissue oxygen saturation, f) postcapillary venous blood flow. Intervention group: Six sessions of extracorporeal focused shock wave for six sessions (2000 impulses, 0,25 mJ/m2 every 1-2 weeks) at both gluteal and thigh regions plus a specific gluteal strength exercise training. Control group: Six sessions of sham extracorporeal focused shock wave for six sessions (2000 impulses, 0,01 mJ/m2 every 1-2 weeks) at both gluteal and thigh regions plus a specific gluteal strength exercise training. Follow-up: 12 weeks. Blinding was achieved for all participants enrolled in the trial, the photograph taking the digital images for the primary outcome measure, the two assessors of the outcome measures, all additional health care providers and for the analyst from the biometrical department. Only one researcher (BJ) was aware of the group assignment performing the randomisation and the extracorporeal shock wave therapy.
This randomised-controlled trial will provide much needed evidence on the clinical effectiveness of focused extracorporal shock wave therapy as an adjunct to gluteal strength training in females suffering cellulite.
Several materials have been used for tissue engineering purposes, since the ideal matrix depends on the desired tissue. Silk biomaterials have come to focus due to their great mechanical properties. As untreated silkworm silk has been found to be quite immunogenic, an alternative could be spider silk. Not only does it own unique mechanical properties, its biocompatibility has been shown already in vivo. In our study, we used native spider dragline silk which is known as the strongest fibre in nature.
Steel frames were originally designed and manufactured and woven with spider silk, harvesting dragline silk directly out of the animal. After sterilization, scaffolds were seeded with fibroblasts to analyse cell proliferation and adhesion. Analysis of cell morphology and actin filament alignment clearly revealed adherence. Proliferation was measured by cell count as well as determination of relative fluorescence each after 1, 2, 3, and 5 days. Cell counts for native spider silk were also compared with those for trypsin-digested spider silk. Spider silk specimens displayed less proliferation than collagen- and fibronectin-coated cover slips, enzymatic treatment reduced adhesion and proliferation rates tendentially though not significantly. Nevertheless, proliferation could be proven with high significance (p<0.01).
Native spider silk does not require any modification to its application as a biomaterial that can rival any artificial material in terms of cell growth promoting properties. We could show adhesion mechanics on intracellular level. Additionally, proliferation kinetics were higher than in enzymatically digested controls, indicating that spider silk does not require modification. Recent findings concerning reduction of cell proliferation after exposure could not be met. As biotechnological production of the hierarchical composition of native spider silk fibres is still a challenge, our study has a pioneer role in researching cellular mechanics on native spider silk fibres.
Introduction: Many studies have demonstrated the existence of an anti-inflammatory, parasympathetic pathway, termed as the inflammatory reflex. Burn-induced heart failure has been investigated in many previous studies. Proinflammatory cytokines, such as TNF-α, IL-1β, and IL-6, have been shown to play a key pathogenetic role and vagus nerve stimulation attenuates proinflammatory cytokine production. This study was designed to evaluate postburn alterations of cardiac functional parameters after vagal electrostimulation. Material and Methods: A 30% total body surface area standardized, full-thickness rat burn model was used. Electric stimulation of the vagus nerve was performed. The following functional cardiac parameters were measured by ventricular microcatheterization: Maximal and minimal left ventricular pressure, mean left ventricular pressure, end-diastolic pressure (EDP), positive and negative pressure rise and fall (±dP/dt), cardiac contractility index, and assessment of the heart rate. Results: Vagus nerve stimulation improved maximal and minimal left ventricular pressure values compared with burn-only animals. End-diastolic pressure was elevated significantly in stimulated animals; however, EDP values were comparable with those in sham-injured animals. Analyzing positive and negative pressure development, ±dP/dt was restored to levels measured in sham-injured animals but not to control animal levels. No variations in heart rate were found. Conclusion: We as well as others have shown that inflammation after burn injury is a key pathogenetic element, and this study provides new evidence that cardiac function is also improved by vagus nerve stimulation. These results lead us to consider novel therapeutic options for the treatment of postburn cardiac dysfunction.
Objective: Nerve regenerative is a complex problem and cell therapy strategies are being developed to enhance axonal regeneration. One approach is to transplant peripheral myelin–forming cells (Schwann cells or olfactory ensheathing cells) that can secrete neurotrophic factors and participate in remyelination of regenerated axons. The objectives of this report are to first review the basic regeneration properties of myelinated axons. Next, to review studies that show functional improvement after transplantation of peripheral myelinating cells in the injured spinal cord. The final objective is to review recent studies using this approach as an adjunct cell therapy for microsurgical repair of peripheral nerve. Methods: Schwann cells and olfactory ensheathing cells were transplanted into injured spinal cord and peripheral nerve. In the microsurgical repair studies, rat sciatic nerves were repaired with epineural sutures (10.0). Olfactory ensheathing cells were transplanted in the experimental group at the time of repair. Histological and behavioral assessment was carried out at 5 weeks postsurgery. Results: Experimental transplantation of olfactory ensheathing cells at the time of microsurgical repair of peripheral nerve leads to increased axonal regeneration across the repair site and improved functional outcome. Conclusions: Olfactory ensheathing cells can integrate and participate in neural repair in both spinal cord and peripheral nerve. They promote axonal sprouting and contribute to remyelination associated with appropriate axon nodal sodium channel clustering necessary for proper impulse conduction. These experimental observations suggest that adjunct cell transplantation with microsurgical repair should be considered as a possible tool in peripheral nerve repair.
Treatment of ruptured Achilles tendons currently constitutes of conservative early functional treatment or surgical treatment either by open or minimal invasive techniques. We hypothesize that an experimental Achilles tendon suture in an animal model significantly deteriorates Achilles tendon microcirculation immediately following suturing.
Fifteen Achilles tendons of eight male Wistar rats (275–325 g) were included. After preparation of the Achilles tendon with a medial paratendinous approach, Achilles tendon microcirculation was assessed using combined Laser-Doppler and spectrophotometry (Oxygen-to-see) regarding:
- tendinous capillary blood flow [arbitrary units AU]
- tendinous tissue oxygen saturation [%]
- tendinous venous filling pressure [rAU]
The main body of the Achilles tendon was measured in the center of the suture with 50 Hz. 10 minutes after Achilles tendon suture (6-0 Prolene), a second assessment of microcirculatory parameters was performed.
Achilles tendon capillary blood flow decreased by 57% following the suture (70 ± 30 AU vs. 31 ± 16 AU; p < 0.001). Tendinous tissue oxygen saturation remained at the same level before and after suture (78 ± 17% vs. 77 ± 22%; p = 0.904). Tendinous venous filling pressure increased by 33% (54 ± 16 AU vs. 72 ± 20 AU; p = 0.019) after suture.
Achilles tendon suture in anaesthetised rats causes an acute loss of capillary perfusion and increases postcapillary venous filling pressures indicating venous stasis. The primary hypothesis of this study was confirmed. In contrast, tendinous tissue oxygen saturation remains unchanged excluding acute intratendinous hypoxia within the first 10 minutes after suture. Further changes of oxygen saturation remain unclear. Furthermore, it remains to be determined to what extent reduced capillary blood flow as well as increased postcapillary stasis might influence tendon healing from a microcirculatory point of view in this animal setting.
We present a case of combined median nerve contusion with immediate loss of sensation after the strangulation with a wakeboarding rope and prolonged referral to our department 72 hours after the injury accompanied by an acute carpal tunnel syndrome with immediate relief of numbness of a significant proportion of the median nerve following surgical decompression.
The palmar branch of the median nerve was surrounded by a significant haematoma in addition to the strangulation damage caused by its more superficial location in contrast to the median nerve.
In case of acute median neuropathy, urgent surgical intervention with exploration, decompression of both, the median nerve and the superficial branch of the median nerve, accompanied by compartment measurements of the forearm should be performed to regain or re-establish neurological integrity.
Deep sternal infections, also known as poststernotomy mediastinitis, are a rare but often fatal complication in cardiac surgery. They are a cause of increased morbidity and mortality and have a significant socioeconomic aspect concerning the health system. Negative pressure wound therapy (NPWT) followed by muscular pectoralis plasty is a quite new technique for the treatment of mediastinitis after sternotomy. Although it could be demonstrated that this technique is at least as safe and reliable as other techniques for the therapy of deep sternal infections, complications are not absent. We report about our experiences and complications using this therapy in a set of 54 patients out of 3668 patients undergoing cardiac surgery in our institution between January 2005 and April 2007.
Transplantation of myelin-forming cells can remyelinate axons, but little is known of the sodium channel organization of axons myelinated by donor cells. Sciatic nerve axons of female wild type mice were transected by a crush injury and Schwann cells (SCs) from green fluorescence protein (GFP)-expressing male mice were transplanted adjacent to the crush site. The male donor cells were identified by GFP fluorescence and fluorescence in situ hybridization (FISH) for Y chromosome. In nerves of GFP-expressing mice, GFP was observed in the axoplasm and in the cytoplasmic compartments of the Schwann cells, but not in the myelin. Following transplantation of GFP-SCs into crushed nerve of wild type mice, immuno-electron microscopic analysis indicated that GFP was observed in the cytoplasmic compartments of engrafted Schwann cells which formed myelin. Nodal and paranodal regions of the axons myelinated by the GFP-SCs were identified by Nav 1.6 sodium channel and Caspr immunostaining, respectively. Nuclear identification of the Y chromosome by FISH confirmed the donor origin of the myelin-forming cells. These results indicate that engrafted GFP-SCs participate in myelination of regenerated peripheral nerve fibers and that Nav 1.6 sodium channel, which is the dominant sodium channel at normal nodes, is reconstituted on the regenerated axons.
Schwann cells; Transplantation; Peripheral nerve
Complications arising from accidental intraarterial drug injections have been described in the past. However, given the multitude of injected substances and complex pathophysiology, guidelines regarding diagnosis and management of patients with intraarterial injections remain vague. As such it remains unclear, when to expect limb ischemia and whether and for how long to monitor patients after intraarterial injections.
We present the case of a "near miss event" in an i.v. drug abuser presenting to the emergency department 3 hours after injection of water dissolved zolpidem (Ambien™) tablets into the right ulnar artery. Chief complaint was forearm pain. Clinical examination at the time revealed no concern for limb ischemia and patient was discharged. The patient returned unplanned 18 hours after injection with an ischemic right hand. Angiography revealed no flow in the distal ulnar artery and minimal flow in the palmar arch. Emergent intraarterial thrombolysis with Urokinase was performed and restored hand perfusion. Clinical follow-up 3 months after injury showed full recovery with regular recapillarisation and normal Allen test.
This case report highlights the need to rigorously monitor patients with suspected intraarterial injections for potential delayed onset of limb ischemia. This is to our knowledge the first described case report of a successful revascularization after prolonged ischemia with delayed onset after zolpidem injection. We recommend close monitoring of these patients for at least 24 hours in addition to starting prophylactic anticoagulation.
The conserved protein domain UPF0005 is a protein family signature distributed among many species including fungi and bacteria. Although of unknown functionality this motif has been found in newly identified antiapoptotic proteins comprising the BI-1 family, namely Bax-inhibitory Protein-1 (BI-1), Lifeguard (LFG), and h-GAAP. In a search for vertebrate proteins presumably belonging to the BI-1 family, we found that Growth-hormone inducible transmembrane protein (Ghitm) is another prospective member of the BI-1 family. Here we characterise Ghitm in a first analysis regarding its phylogeny, expression in cancer cell lines, and proteomical properties.
protein family; Bax-inhibitor; programmed cell death; bioinformatics; apoptosis inhibitors; transmembrane protein
Repair success for injuries to the flexor tendon in the hand is often limited by the in vivo behaviour of the suture used for repair. Common problems associated with the choice of suture material include increased risk of infection, foreign body reactions, and inappropriate mechanical responses, particularly decreases in mechanical properties over time. Improved suture materials are therefore needed. As high-performance materials with excellent tensile strength, spider silk fibres are an extremely promising candidate for use in surgical sutures. However, the mechanical behaviour of sutures comprised of individual silk fibres braided together has not been thoroughly investigated. In the present study, we characterise the maximum tensile strength, stress, strain, elastic modulus, and fatigue response of silk sutures produced using different braiding methods to investigate the influence of braiding on the tensile properties of the sutures. The mechanical properties of conventional surgical sutures are also characterised to assess whether silk offers any advantages over conventional suture materials. The results demonstrate that braiding single spider silk fibres together produces strong sutures with excellent fatigue behaviour; the braided silk sutures exhibited tensile strengths comparable to those of conventional sutures and no loss of strength over 1000 fatigue cycles. In addition, the braiding technique had a significant influence on the tensile properties of the braided silk sutures. These results suggest that braided spider silk could be suitable for use as sutures in flexor tendon repair, providing similar tensile behaviour and improved fatigue properties compared with conventional suture materials.
Tissue engineering plays an important role in the production of skin equivalents for the therapy of chronic and especially burn wounds. Actually, there exists no (cellularized) skin equivalent which might be able to satisfactorily mimic native skin. Here, we utilized a laser-assisted bioprinting (LaBP) technique to create a fully cellularized skin substitute. The unique feature of LaBP is the possibility to position different cell types in an exact three-dimensional (3D) spatial pattern. For the creation of the skin substitutes, we positioned fibroblasts and keratinocytes on top of a stabilizing matrix (Matriderm®). These skin constructs were subsequently tested in vivo, employing the dorsal skin fold chamber in nude mice. The transplants were placed into full-thickness skin wounds and were fully connected to the surrounding tissue when explanted after 11 days. The printed keratinocytes formed a multi-layered epidermis with beginning differentiation and stratum corneum. Proliferation of the keratinocytes was mainly detected in the suprabasal layers. In vitro controls, which were cultivated at the air-liquid-interface, also exhibited proliferative cells, but they were rather located in the whole epidermis. E-cadherin as a hint for adherens junctions and therefore tissue formation could be found in the epidermis in vivo as well as in vitro. In both conditions, the printed fibroblasts partly stayed on top of the underlying Matriderm® where they produced collagen, while part of them migrated into the Matriderm®. In the mice, some blood vessels could be found to grow from the wound bed and the wound edges in direction of the printed cells. In conclusion, we could show the successful 3D printing of a cell construct via LaBP and the subsequent tissue formation in vivo. These findings represent the prerequisite for the creation of a complex tissue like skin, consisting of different cell types in an intricate 3D pattern.
Autologous cells can be used for a bioactivation of osteoimplants to enhance osseointegration. In this regard, adipose derived stem cells (ASCs) offer interesting perspectives in implantology because they are fast and easy to isolate. However, not all materials licensed for bone implants are equally suited for cell adhesion. Surface modifications are under investigation to promote cytocompatibility and cell growth. The presented study focused on influences of a Nitinol-nanoparticle coating on ASCs. Possible toxic effects as well as influences on the osteogenic differentiation potential of ASCs were evaluated by viability assays, scanning electron microscopy, immunofluorescence and alizarin red staining. It was previously shown that Nitinol-nanoparticles exert no cell toxic effects to ASCs either in soluble form or as surface coating. Here we could demonstrate that a Nitinol-nanoparticle surface coating enhances cell adherence and growth on Nitinol-surfaces. No negative influence on the osteogenic differentiation was observed. Nitinol-nanoparticle coatings offer new possibilities in implantology research regarding bioactivation by autologous ASCs, respectively enhancement of surface attraction to cells.