Neck, J.W. van

Changes of mandibular ramal height, during growth in unilateral hemifacial microsomia patients and unaffected controls (Article)

2013-03-01T00:00:00Z

The aim of this study was to design mandibular ramal height growth curves for patients with HFM and compare those with the curves for a Dutch reference population. Two hundred fifty-one pre-operative orthopantomograms (OPTs) from 84 patients with unilateral HFM were used in conjunction with a control set of 2260 OPTs from 329 healthy individuals from the Nijmegen Growth Study (NGS) to determine mandibular ramal distances. For grades I/IIa and IIb/III, and for both sides, growth curves were constructed for mandibular ramal height with a linear curve-fitting procedure. This procedure revealed a significant difference between HFM patients and the NGS control group (p < 0.001); both in the mild and severe group mandibular ramal height differed significantly between the affected and non-affected side (p < 0.001). Growth was similar between HFM patients and the NGS control group. HFM patients therefore start with a smaller mandible and end with a smaller mandible, but experience growth similar to the Dutch normal population. These growth curves may aid the timing and determination of the combined surgical orthodontic treatment plan for HFM patients.

Metric properties of advanced imaging methods in osteoarthritis of the hand: A systematic review (Article)

2013-01-24T00:00:00Z

Objective: To assess the value of advanced imaging techniques in the detection of hand osteoarthritis (OA) and hand OA progression. Methods: PubMed/Medline and Embase were searched until April 2012 for studies on imaging of hand OA that presented quantitative data on validity, reliability or responsiveness. Articles presenting only data on conventional radiography (CR) were excluded. Methodological quality was assessed by the Quality Assessment of Diagnostic Accuracy Studies (QUADAS) checklist for validity, the Quality Appraisal of Reliability Studies (QAREL) for reliability and the COSMIN (COnsensus-based Standards for the selection of health Measurement INstruments) for responsiveness. Results: Of 627 citations, 25 studies on ultrasonography (US), MRI or scintigraphy were included. No studies on CT, positron emission tomography or single photon emission CT met our eligibility criteria. Validity was generally assessed against healthy controls, CR or clinical examination. Overall, US and MRI detected more disease than CR and found significant differences between patients and healthy controls. Scintigraphy detected fewer pathological joints than CR. Intra- and inter-reader reliability varied for US (κ=0.01-1.0) and MRI (κ=0.15-0.84 and intraclass correlation coefficient=0.21-0.99) and was good for scintigraphy (κ=0.61-0.84). There were no responsiveness studies for MRI. US responsiveness studies showed a reduction of soft-tissue changes after treatment which correlated with decrease in pain (r=0.7-0.8). For scintigraphy, scores decreased over time while CR showed progression of hand OA. Conclusions: MRI and US seem to be the most promising candidates for early detection of hand OA and for future use in clinical trials. However, further research is needed to improve scoring methods, to compare US with MRI, to confirm reliability of MRI and to further determine the responsiveness of US and MRI. Copyright Article author (or their employer) 2013.

Comparing scaffold-free and fibrin-based adipose-derived stromal cell constructs for adipose tissue engineering: An in vitro and in vivo study (Article)

2012-12-07T00:00:00Z

Success of adipose tissue engineering for soft tissue repair has been limited by insufficient adipogenic differentiation, an unfavorable host response, and insufficient vascularization. In this study, we examined how scaffold-free spheroid and fibrin-based environments impact these parameters in human adipose-derived stromal cell (ASC)-based adipose constructs. ASCs were differentiated in spheroids or fibrin-based constructs. After 7 days, conditioned medium was collected and spheroids/fibrin-based constructs were either harvested or implanted subcutaneously in athymic mice. Following 7 days of implantation, the number of blood vessels in fibrin-based constructs was significantly higher than in spheroids (93 ± 45 vs. 23 ± 11 vessels/mm2) and the inflammatory response to fibrin-based constructs was less severe. The reasons for these results were investigated further in vitro. We found that ASCs in fibrin-based constructs secreted significantly higher levels of the angiogenic factors VEGF and HGF and lower levels of the inflammatory cytokine IL-8. Furthermore, ASCs in fibrin-based constructs secreted significantly higher levels of leptin and showed a 2.5-fold upregulation of the adipogenic transcription factor PPARG and a fourfold to fivefold upregulation of the adipocyte-specific markers FABP4, perilipin, and leptin. These results indicate that fibrin-based ASC constructs are potentially more suitable for ASC-based adipose tissue reconstruction than scaffold-free spheroids.

Craniofacial morphology in unilateral hemifacial microsomia (Article)

2012-11-30T00:00:00Z

Hemifacial microsomia (HFM) is a complex three-dimensional congenital condition that is characterized by mandibular hypoplasia and unilateral or bilateral microtia; although, other facial structures may be affected. Little is known about craniofacial growth and morphology in patients with HFM; therefore, we examined 75 HFM patients by means of a cephalometric analysis in a longitudinal study on serial lateral cephalograms. We hypothesized that the growth of several facial structures on both sides of HFM patients would be different compared to Dutch controls. We determined patients with HFM had more retruded mandibles and maxillae and a more vertical morphology compared to the reference population. In addition, there was a more retruded and vertical pattern on the affected side compared to the unaffected side and in patients with a severe condition compared to those with a mild condition. 'Mild' HFM patients were more similar to the Dutch reference population than the 'severe' HFM patients. Individual HFM growth curves showed very high inter-variability, further strengthening the need for individualized treatment plans that consider all three dimensions and the severity of the condition.

Diabetes-impaired wound healing is improved by matrix therapy with heparan sulfate glycosaminoglycan mimetic OTR4120 in rats (Article)

2012-10-01T00:00:00Z

Wound healing in diabetes is frequently impaired, and its treatment remains a challenge. We tested a therapeutic strategy of potentiating intrinsic tissue regeneration by restoring the wound cellular environment using a heparan sulfate glycosaminoglycan mimetic, OTR4120. The effect of OTR4120 on healing of diabetic ulcers was investigated. Experimental diabetes was induced by intraperitoneal injection of streptozotocin. Seven weeks after induction of diabetes, rats were ulcerated by clamping a pair of magnet disks on the dorsal skin for 16 h. After magnet removal, OTR4120 was administered via an intramuscular injection weekly for up to 4 weeks. To examine the effect of OTR4120 treatment on wound healing, the degree of ulceration, inflammation, angiogenesis, and collagen synthesis were evaluated. We found that OTR4120 treatment significantly reduced the degree of ulceration and the time of healing. These effects were associated with reduced neutrophil infiltration and macrophage accumulation and enhanced angiogenesis. OTR4120 treatment also increased the collagen content with an increase of collagen type I biosynthesis and reduction of collagen type III biosynthesis. Moreover, restoration of the ulcer biomechanical strength was significantly enhanced after OTR4120 treatment. This study shows that matrix therapy with OTR4120 improves diabetes-impaired wound healing.

Heparan Sulfate Proteoglycan Mimetics Promote Tissue Regeneration: An Overview (In Book)

2012-09-05T00:00:00Z

Vascularization of prevascularized and non-prevascularized fibrin-based human adipose tissue constructs after implantation in nude mice (Article)

2012-03-01T00:00:00Z

Adipose regeneration strategies have been hampered by the inability to supply an adequate vascular supply following implantation. Vascularization in vitro, also called prevascularization, is a promising method that could promote the vascularization of engineered adipose tissue constructs upon implantation. In this study we compared the ability of prevascularized-to-non-prevascularized fibrin-based human adipose tissue to promote vascularization. Human adipose tissue-derived stromal cells (ASCs) and different mixtures (1:1, 1:2 and 1:5) of ASCs with human umbilical vein endothelial cells (HUVECs) were cultured in fibrin at two different densities (1.0 × 106and 10 × 106cells/ml) for 7 days. Histological analysis revealed that prevascular structures formed in 1:5 ASC/HUVEC fibrin-based constructs seeded with a total of 10 × 106cells/ml. These constructs and ASC-only constructs were implanted subcutaneously in athymic mice for 7 days and generated lipid-containing grafts. The numbers and densities of blood vessels within the ASC/HUVEC constructs were similar to those of ASC-only constructs. Furthermore, immunostaining studies demonstrated human-derived vasculature within a few of the ASC/HUVEC and ASC-only constructs. A subset of this human-derived vasculature contained erythrocytes, indicating integration with the host vasculature. In conclusion, our study indicated no difference in the rate of vascularization of prevascularized ASC/HUVEC and non-prevascularized ASC-only fibrin-based constructs, suggesting that prevascularization of these fibrin-based constructs does not promote vascularization. Our results further indicated that not only endothelial cells, but also ASCs may contribute to the formation of vascular lumina upon implantation. This finding is interesting, since it demonstrates the possibility of vascularized adipose tissue engineering from a single cell source.

Characterization of a three-dimensional mucosal equivalent: Similarities and differences with native oral mucosa (Article)

2012-02-01T00:00:00Z

The aim of this study was to create and characterize a tissue-engineered mucosal equivalent (TEM) that closely resembles native mucosa. TEM consists of human primary keratinocytes and fibroblasts isolated from biopsies taken from healthy donors and seeded onto a de-epidermized dermis and cultured for 14 days at the air/liquid interface. The structure of TEM was examined and compared with native nonkeratinizing oral mucosa (NNOM). The various components of the newly formed epidermal layer, basement membrane and underlying connective tissue were analyzed using immunohistochemistry. The mucosal substitute presented in this study showed a mature stratified squamous epithelium that was similar to that of native oral mucosa, as demonstrated by K19, desmoglein-3 and involucrin staining. In addition, the expression of basement membrane components collagen type IV, laminin-5 and integrin α6 and β4 in TEM proved to be consistent with native oral mucosa. The expression of PAS, Ki67, K10 and K13, however, appeared to be different in TEM compared to NNOM. Nevertheless, the similarities with native oral mucosa makes TEM a promising tool for studying the biology of mucosal pathologies such as oral mucositis or fibrosis as well as the development of new therapies. Copyright

Heparan sulfate glycosaminoglycan mimetic improves pressure ulcer healing in a rat model of cutaneous ischemia-reperfusion injury (Article)

2011-07-01T00:00:00Z

Pressure ulcers are a major clinical problem, with a large burden on healthcare resources. This study evaluated the effects of the heparan sulfate glycosaminoglycan mimetic, OTR4120, on pressure ulceration and healing. Ischemia-reperfusion (I-R) was evoked to induce pressure ulcers by external clamping and then removal of a pair of magnet disks on rat dorsal skin for a single ischemic period of 16 hours. Immediately after magnet removal, rats received an intramuscular injection of OTR4120 weekly for up to 1 month. During the ischemic period, normal skin perfusion was reduced by at least 60% and at least 20-45% reperfused into the ischemic region after compression release. This model caused sustained skin incomplete necrosis for up to 14 days and led to grade 2-3 ulcers. OTR4120 treatment decreased the area of skin incomplete necrosis and degree of ulceration. OTR4120 treatment also reduced inflammation and increased angiogenesis. In OTR4120-treated ulcers, the contents of vascular endothelial growth factor, platelet-derived growth factor, and transforming growth factor beta-1 were increased. Moreover, OTR4120 treatment promoted early expression of alpha-smooth muscle actin and increased collagen biosynthesis. Long-term restoration of wounded tissue biomechanical strength was significantly enhanced after OTR4120 treatment. Taken together, we conclude that OTR4120 treatment reduces pressure ulcer formation and potentiates the internal healing bioavailability.

Hypoxia preconditioning of tissue-engineered mucosa enhances its angiogenic capacity in vitro (Article)

2011-06-01T00:00:00Z

Improving vascularization of tissue-engineered oral mucosa (TEM) is a major challenge in the field of plastic surgery. Hypoxia is a stimulator of angiogenesis through a number of mechanisms. Therefore, hypoxia is a critical parameter that can be controlled in an effort to improve angiogenesis. In the present study we studied the secretion of a number of angiogenic factors during hypoxia exposure and evaluated the effect of TEM conditioned medium on endothelial cells. TEM was constructed by seeding human oral mucosa keratinocytes and fibroblasts on acellular human donor skin. TEM was exposed to hypoxia during 6, 12, and 24h. Cellular hypoxia was assessed by immunolocalization of the hypoxia-inducible factor-1α. Secretion of vascular endothelial growth factor, placental growth factor (PlGF), tissue inhibitors of matrix metalloproteinases-1 and -2, and the activity of matrix metalloproteinase-9 significantly increased during hypoxia exposure. Moreover, conditioned medium from hypoxic TEM strongly enhanced endothelial cell proliferation and migration. In vitro exposure of TEM to hypoxia improves its capacity to support endothelial cell proliferation and migration, which suggests that hypoxia preconditioning of TEM potentially improves angiogenic responses for in vivo implantation.

Unexpected healing of radiation-induced scalp lesions with OTR4120, a heparan sulfate mimetic (Article)

2011-05-01T00:00:00Z

Ultrasound-guided needle positioning near the sciatic nerve to elicit compound muscle action potentials from the gastrocnemius muscle of the rat (Article)

2011-01-15T00:00:00Z

The use of ultrasound-guided electrode positioning in near-nerve myography was investigated. This is a minimally invasive technique that allows repeated measurements to increase accuracy and hence decreases animal numbers. Ultrasound imaging of the sciatic nerve was performed in nine rats using a 55. MHz high-end transducer. Once visualised, a monopolar needle electrode was placed through the skin near this nerve. Upon stimulation, two surface electrodes, placed over the gastrocnemius muscle, recorded compound muscle action potentials (CMAPs). Reproducibility was tested having two teams of investigators perform the recordings consecutively. Reliability of the procedure was determined by comparing the ultrasound method to the conventional technique, which requires an incision through muscle and skin to expose the sciatic nerve. In all animals the sciatic nerve was visible on ultrasound images. Both methods showed CMAP latencies (duration was determined as the time interval between the onset latency and positive peak). The conventional method had a mean latency of 3.4 ± 0.5. ms, our method had a mean latency of 3.3 ± 0.5. ms. Reproducibility was excellent (observed latencies and amplitudes: 3.3 versus 3.3. ms and 25.6 ± 5.1. mV versus 22.5 ± 8.8. mV) resulting in a coefficient of variation for duration of 2.1% and for amplitude 6.7%. Interclass correlation coefficient was 0.828 for duration. Comparing the three different measurements no significant differences were found and our new method can therefore be considered reliable and comparable to the conventional method.Ultrasound-guided near-nerve needle positioning is a reproducible and reliable minimally invasive method for selectively eliciting CMAPs, which allows repeated CMAP measurements for studying nerve regeneration in rats.

Surgical management of neuroma pain: A prospective follow-up study (Article)

2010-12-01T00:00:00Z

Painful neuromas can cause severe loss of function and have great impact on the daily life of patients. Surgical management remains challenging; despite improving techniques, success rates are low. To accurately study the success of surgical neuroma treatment and factors predictive of outcome, a prospective follow-up study was performed. Between 2006 and 2009, pre- and post-operative questionnaires regarding pain (VAS, McGill), function (DASH), quality of life (SF-36), symptoms of psychopathology (SCL-90), epidemiologic determinants and other outcome factors were sent to patients surgically treated for upper extremity neuroma pain. Pain scores after diagnostic nerve blocks were documented at the outpatient clinic before surgery. Thirty-four patients were included, with an average follow up time of 22 months. The mean VAS score decreased from 6.8 to 4.9 after surgery (p < 0.01), 19 (56%) of patients were satisfied with surgical results. Upper extremity function improved significantly (p = 0.001). Neuroma patients had significantly lower quality of life compared to a normal population. Employment status, duration of pain and CRPS symptoms were found to be prognostic factors. VAS scores after diagnostic nerve block were predictive of post-operative VAS scores (p = 0.001). Furthermore, smoking was significantly related to worse outcome (relative risk: 2.10). The results could lead to improved patient selection and treatment strategies. If a diagnostic nerve block is ineffective in relieving pain, patients will most likely not benefit from surgical treatment. Patients should be encouraged to focus on activity and employment instead of their symptoms. Smoking should be discouraged in patients who will undergo surgical neuroma treatment.

Delay of denervation atrophy by sensory protection in an end-to-side neurorrhaphy model: A pilot study (Article)

2010-12-01T00:00:00Z

Object: Temporary sensory innervation delays the atrophy process. A major disadvantage of most experimental models is that sensory-protected muscles must be denervated a second time to allow reinnervation by the affected nerve. The aim of this study was to assess the effect of sensory protection on denervated gastrocnemius muscle in an end-to-side neurorrhaphy model, in which denervated muscles may be preserved until axons of the native nerve reach their target without the necessity for a second operation. Methods: The tibial nerve of 24 female Lewis rats was transected. Twelve animals acted as the controls. In the other 12 animals, the end of the sural nerve was connected to the side of the distal tibial nerve stump (sensory protection group). At 5 and 10 weeks, wet gastrocnemius muscle weight was reported as a ratio of the operated to the unoperated side. For histological analysis, muscle samples were rapidly frozen and sections were stained with haematoxylin and eosin, Oil Red O stain and modified Gomori trichrome stain. Results: The difference between the sensory protection group and the control group was statistically significant at 5 (0.36 ± 0.01 and 0.29 ± 0.01, respectively; p < 0.001) and 10 weeks postoperatively (0.28 ± 0.01 and 0.19 ± 0.00, respectively; p < 0.001). Histological observations revealed that sensory-protected muscles underwent less atrophy. Conclusion: Sensory protection delays atrophy in an end-to-side neurorrhaphy model.

Prevascular structures promote vascularization in engineered human adipose tissue constructs upon implantation (Article)

2010-09-01T00:00:00Z

Abstract Vascularization is still one of the most important limitations for the survival of engineered tissues after implantation. In this study, we aim to improve the in vivo vascularization of engineered adipose tissue by pre-forming vascular structures within in vitro-engineered adipose tissue constructs that can integrate with the host vascular system upon implantation. Different cell culture media were tested and different amounts of human adipose tissue-derived mesenchymal stromal cells (ASC) and human umbilical vein endothelial cells (HUVEC) were combined in spheroid co-cultures to obtain optimal conditions for the generation of prevascularized adipose tissue constructs. Immunohistochemistry revealed that prevascular structures were formed in the constructs only when 20% ASC and 80% HUVEC were combined and cultured in a 1:1 mixture of endothelial cell medium and adipogenic medium. Moreover, the ASC in these constructs accumulated lipid and expressed the adipocyte-specific gene fatty acid binding protein-4. Implantation of prevascularized ASC/HUVEC constructs in nude mice resulted in a significantly higher amount of vessels (3717 vessels/mm2) within the constructs compared to non-prevascularized constructs composed only of ASC (3 4 vessels/mm2). Moreover, a subset of the pre-formed human vascular structures (3.6±4.2 structures/mm2) anastomosed with the mouse vasculature as indicated by the presence of intravascular red blood cells. Our results indicate that pre-formed vascular structures within in vitro-engineered adipose tissue constructs can integrate with the host vascular system and improve the vascularization upon implantation.

Insufficient pain relief after surgical neuroma treatment: Prognostic factors and central sensitisation (Article)

2010-09-01T00:00:00Z

Background: Treatment of patients with neuromatous pain is difficult. Numerous treatment methods have been described, but none has been completely effective in providing sufficient pain relief. Patient-specific prognostic factors, predicting pain after surgical neuroma treatment, can help clinicians in the process of patient treatment and care. Methods: A computerised bibliographical database (PubMed Medline) was searched for articles concerning prognostic factors predicting the outcome of surgical neuroma treatment, and all the reference lists were checked. Results: Evidence for predicting the outcome was found for neuromas of the radial sensory branch and digital nerves, discrete nerve syndrome, workers compensation, employment status, litigation involvement, duration of pain and number of previous operations. Psychosocial problems are often found in neuroma patients. In chronic neuropathic pain patients, changes in the central nervous system at the level of spinal cord and in the somatosensory cortex can be found. Conclusions: Neuromas of the radial sensory branch and digital nerves, discrete nerve syndrome, workers' compensation, employment status, litigation involvement, duration of pain and number of previous operations appear to predict the amount of pain after neuroma surgery. However, in a minority of patients, a bad outcome cannot be explained by these factors; in these patients, central sensitisation and psychosocial factors may play a role in maintaining pain. Research focussing on prognostic factors and the central changes induced by painful peripheral injury can lead to new and improved clinical treatment algorithms for the relief and prevention of chronic neuropathic pain.

Histological validation of ultrasound-guided neurography in early nerve regeneration (Article)

2009-12-01T00:00:00Z

Ultrasound-guided near-nerve neurography is a new tool that can be used to assess nerve regeneration before reinnervation occurs. In this study, ultrasound-guided near-nerve measurements were validated against axon diameter counts in rabbits during a 15-week regeneration period after a crush lesion of their peroneal nerve. The course of the nerve was determined ultrasonically, and the active near-nerve needle electrode was maneuvered just next to the nerve under ultrasound guidance. Measured action potentials were compared with axon diameter counts from histological sections of these same nerves. A moderate to good positive correlation was found, which reached a maximum of 0.7 at a cut-off of 3 μm, corresponding to the minimal size of the myelinated axons. Our results suggest that, following a similar validation study in humans, ultrasound-guided near-nerve neurography may be clinically useful when early evaluation of nerve activity is needed.

High-resolution ultrasonography of the cutaneous nerve branches in the hand and wrist (Article)

2009-12-01T00:00:00Z

Ultrasonography can be used in the diagnosis of various neuropathies, including nerve injury. Nerves often involved in traumatic and iatrogenic injury are small cutaneous branches in the hand and wrist, which cannot be seen in detail using current ultrasound probes. This study explored the potential of high-resolution ultrasonography in seeing these nerve branches in the human. The VisualSonics Vevo 770 system with a 15-82.5 MHz probe was compared to a commonly used 5-12 MHz probe and ultrasound machine. The accuracy was validated by ultrasound guided dye injection into cadaver nerves, with subsequent anatomical dissection and verification. Results were confirmed in two healthy volunteers. The Vevo 770 system was able to accurately identify the small cutaneous nerves. It could also depict the median nerve and its fascicles in greater detail. This may be useful for clinical diagnosis, localisation and follow-up of neuropathies and nerve injuries.

Cold Intolerance in Surgically Treated Neuroma Patients: A Prospective Follow-Up Study (Article)

2009-11-01T00:00:00Z

Purpose: Cold intolerance may impose great changes on patients' lifestyle, work, and leisure activities, and it is often severely disabling. This study aims to investigate the prevalence and severity of cold intolerance in patients with injury-related neuromas of the upper extremity and improvement of symptoms after surgical treatment. Furthermore, we try to find predictors for cold intolerance and correlations with other symptoms. Methods: Between January 2006 and February 2009, 34 consecutive patients with surgically treated neuroma-specific neuropathic pain of the upper extremities were sent a questionnaire composed of general questions concerning epidemiologic variables and several specific validated questionnaires, including the Visual Analog Scale for pain. To estimate the prevalence of cold intolerance objectively in neuroma patients, we used the validated CISS (Cold Intolerance Symptom Severity) questionnaire with a prespecified cutoff point. Results: The CISS questionnaire was filled out by 33 patients before and 30 after surgery for neuroma-specific neuropathic pain, with a mean follow-up time of 24 months. We found a prevalence of cold intolerance of 91% before surgery, with a mean CISS score above the cutoff point for abnormal cold intolerance. After surgery, the prevalence of cold intolerance and the mean CISS score were not significantly different, whereas the mean Visual Analog Scale score decreased significantly (p < .01). CISS scores were lower in patients with neuromas associated with sharp injury of the peripheral nerve (p = .02). A higher VAS score correlated significantly with a higher CISS score (p = .01). Conclusions: Cold intolerance is a difficult and persistent problem that has a high prevalence in patients with a painful injury-related neuroma. There seems to be a relationship between severity of cold intolerance as measured by CISS, pain as measured by the Visual Analog Scale, and type of injury. Cold intolerance may not disappear with time or surgical treatment. Type of study/level of evidence: Therapeutic IV.

Stimulated neovascularization, inflammation resolution and collagen maturation in healing rat cutaneous wounds by a heparan sulfate glycosaminoglycan mimetic, OTR4120 (Article)

2009-11-01T00:00:00Z

Heparan sulfate glycosaminoglycans (HS-GAGs) are not only the structural elements of tissue architecture but also regulate the bioavailability and transduction pathways of heparan sulfate-bound polypeptides released by cells or the extracellular matrix. Heparan sulfate-bound polypeptides include inflammatory mediators, chemokines, angiogenic factors, morphogens, and growth-promoting factors that induce cell migration, proliferation, and differentiation in wound healing. OTR4120, a polymer engineered to mimic the properties of HS-GAGs, is used to replace the natural HS-GAGs that are degraded during wound repair, and enhance the tissue regeneration by preserving the cellular microenvironment and the endogenous signals needed for tissue regeneration. We previously demonstrated that OTR4120 treatment had a long-term effect on increasing breaking strength and vasodilation in healing rat full-thickness excisional wounds. The present study investigates the underlying mechanisms of the effects of OTR4120 treatment in improving the quality of cutaneous wound repair. We found that OTR4120 treatment stimulated inflammation resolution and increased neovascularization. OTR4120 treatment also promoted epidermal migration and proliferation during reepithelialization. Moreover, the granulation tissue formation and collagen maturation were improved in OTR4120-treated wounds. Three months after wounding, the effects of OTR4120 treatment on vascularization and inflammation resolution were normalized, except for an improved neodermis. We conclude that OTR4120 is a potential matrix therapeutic agent that ensures the quality of normal cutaneous wound repair and may restore impaired wound healing characterized by deficient angiogenesis and prolonged inflammation.

Histomorphometric comparison between continuous and discontinuous distraction osteogenesis (Article)

2009-10-01T00:00:00Z

Introduction: Experimental research on optimising the distraction protocol has been performed extensively in the past. However, relatively little research has been done on the rhythm of distraction. Findings in the orthopaedic literature showed that the outcome of distraction osteogenesis (DO) is positively influenced by increasing the rhythm of distraction. The aim of this study is to quantitatively compare continuous with discontinuous rhythms of distraction in rabbits. Materials and methods: Tissue blocks of regenerated bone were harvested from thirty-eight young adult female New-Zealand White rabbits. After a latency period of three days, rabbits were subjected for eleven days to either single daily activation of the distractor at a rate of 0.9 mm/d, or triple daily activation at a rate of 0.9 mm/d, or continuous activation at a rate of 0.9 mm/d. After three weeks of consolidation, bone regenerates were analysed using histomorphometry. Results: The continuous DO group showed significantly (p < .01) more regenerate bone volume in the central part of the regenerate than the discontinuous DO groups. Higher osteoblastic activity was seen, as well as more blood vessels (p < .05). Bone volume and the number of blood vessels correlated significantly in the central part of the regenerate (p < .05). Also, the early mineral apposition rate (MAR) was higher than the late MAR (p < .05). Conclusions: Continuous DO significantly accelerates bone formation when compared with discontinuous DO.

Continuous Versus Discontinuous Distraction: Evaluation of Bone Regenerate Following Various Rhythms of Distraction (Article)

2009-04-01T00:00:00Z

Purpose: To investigate continuous distraction osteogenesis (DO) of the nasal bones in a rabbit model, and to compare data from this continuous DO study with data from a previously conducted discontinuous DO study. In addition, radiographic and ultrasonographic bone-fill scores were determined to investigate whether these scores provided reliable predictive value for the amount of new bone formation in the distraction area. Materials and Methods: Skeletally mature female New Zealand White rabbits were subjected to distraction of the nasal bones. A custom-made continuous distractor was used to perform automatic non-stop distraction. Bone data were obtained from radiography, ultrasonography, and microcomputed tomography. Data from this experiment were compared with data from a previous study on discontinuous distraction rhythms. Results: Ultrasonographic bone-fill scores correlated significantly to actual bone volume in contrast to radiographic bone-fill scores. Bone volume was significantly higher in the continuous DO group compared with the discontinuous DO groups. Conclusion: Continuous distraction resulted in accelerated osteogenesis compared with discontinuous distraction. Furthermore, bone-fill scores based on ultrasonography showed a significant correlation with actual bone volumes.

Auto-crosslinked hyaluronic acid gel accelerates healing of rabbit flexor tendons in vivo (Article)

2009-03-01T00:00:00Z

This study's purpose was to assess the in vivo effect of auto-crosslinked hyaluronic acid (HA) gel, a natural HA derivative with increased viscosity and tissue residence time, on adhesions and healing of injured and surgically repaired rabbit digital flexor tendons. The second and third right deep digital flexor tendons from 48 rabbits (n = 96 tendons) were cut and repaired with a modified Kessler and running peripheral suture. Animals were randomized to two groups, receiving either HA gel or saline injected around both freshly repaired tendons. After 2, 3, 6, and 12 weeks, six rabbits in each group were euthanized. Tendon pull-out force and breaking strength were measured as a value for adhesion formation and tendon healing, respectively. A histological assessment of adhesions and healing was related to the mechanical results.Asignificantly faster increase in breaking strength was found in HA gel-treated compared to saline-treated tendons; this coincided with a significantly accelerated tissue repair response after injury. No significant difference in adhesion formation was found between the two groups at any time. Our results indicate a significant acceleration of in vivo healing of tendons treated with HA gel. Adhesion formation was unaffected. These results could have important clinical value in promoting rehabilitation after tendon injury.

Linear mandibular measurements: Comparison between orthopantomograms and lateral cephalograms (Article)

2009-03-01T00:00:00Z

Objective: To investigate the reliability of length measurements of the mandible by comparing orthopantomograms (OPTs) with lateral cephalograms. Design: Observational study. Setting: OPTs and lateral cephalograms were taken of 20 human dry skulls. Four orthodontists and four maxillofacial surgeons located landmarks on all radiographs using a computer program for cephalometric measurements. Intraobserver and interobserver variability in locating landmarks was assessed, as well as positioning of the skulls prior to radiography between the x-ray assistants. Magnification differences between the left and right side of the mandible on the OPT were determined for five skulls. Kappa statistics were used to calculate the intraclass correlation coefficient for intraobserver and interobserver differences. An F test was used to assess differences between methods and between type of observer. Results: No significant differences were found in the magnification factor of the left and right side of the mandible. Compared with a lateral cephalogram, the OPT had comparable reliability in measuring mandibular distances condyliongonion, gonion-menton, and condylion-menton. No significant differences were observed between the x-ray assistants in taking the OPTs and lateral cephalograms or in repositioning the skulls. Significant differences were found between orthodontists and maxillofacial surgeons for landmark measurements. Conclusion: An OPT is as reliable as a lateral cephalogram for linear measurements of the mandible (condylion-gonion, gonion-menton, and condylion-menton).

Angiogenic Capacity of Human Adipose-Derived Stromal Cells during Adipogenic Differentiation: An In Vitro Study (Article)

2009-02-01T00:00:00Z

Background: Improving vascularization of engineered adipose tissue constructs is a major challenge in the field of plastic surgery. Although human adipose-derived stromal cells (hASCs) are known to release factors that stimulate new blood vessel formation, detailed information about the effects of adipogenic differentiation on the angiogenic potential of hASCs remains largely unknown. In the present study, we studied the expression and secretion of a large panel of angiogenic factors during hASC differentiation and evaluated the effects of hASC-conditioned medium (hASC-CM) on endothelial cells. Methods: hASCs were cultured on adipogenic medium or basal medium. Conditioned medium was collected, and cells were harvested following 0, 3, 7, 14, and 22 days of culture. The stage of adipogenic differentiation of hASC was assessed using Oil Red O staining, fatty acid binding protein-4 gene expression, and glycerol-3-phosphate dehydrogenase activity. Results: Gene expression of vascular endothelial growth factor (VEGF), placental growth factor, angiopoietin-1 (ANGPT1), angiopoietin-2 (ANGPT2), and protein secretion of VEGF significantly increased during short-term adipogenic differentiation of hASCs. Moreover, conditioned medium from differentiated hASCs strongly enhanced endothelial cell numbers compared to conditioned medium from undifferentiated hASCs. Conclusion: In vitro adipogenic differentiation of hASCs improves their ability to support endothelial viable cell numbers and suggests that hASCs differentiated for a short period potentially improve angiogenic responses for in vivo implantation.

Sensory Testing of Inferior Alveolar Nerve Injuries: A Review of Methods Used in Prospective Studies (Article)

2009-02-01T00:00:00Z

Purpose: The inferior alveolar nerve (IAN) can be injured during trauma or surgery. So far there is no consensus for evaluating IAN injury. This study aimed to identify a testing method suitable for daily clinical practice which allows us to identify nerve injury, grade its severity, and monitor its recovery. Materials and Methods: Covering a 20-year period, prospective studies on sensory changes after mandibular procedures were reviewed regarding sensory testing methods; 75 studies on third molar removal, osteotomy, fracture, and implants were included. Results: These studies reported varying incidences. In third molar removal and implant studies, a limited number of sensory tests were used, whereas in osteotomy and fracture studies more detailed testing was performed, using reproducible tests like light touch test with Semmes-Weinstein monofilaments and 2-point discrimination. Conclusions: Sensory function was not uniformly tested and presented, making a comparison of data impossible and highlighting the need for uniform testing methodology. Based on the results of this review, the light touch test with Semmes-Weinstein monofilaments for grading is recommended, using a grid and control site describing unilateral or bilateral nerve injury. Additionally, a visual analog scale-based questionnaire should be used to evaluate subjective sensibility. Using this method to test IAN injuries will allow comparison of future studies and provide valuable insight in the severity and prognosis of IAN injuries.

Rabbits as a model for research into craniofacial distraction osteogenesis (Article)

2008-12-01T00:00:00Z

Various factors affect the choice of the appropriate animal for craniofacial research. We have evaluated the rabbit as a suitable animal for research on craniofacial distraction osteogenesis. We describe our experience with housing and handling them, surgical and experimental protocols, and compare them with other animals. We introduce, and describe the use of, a continuous hydraulic distractor on the nasal bones of the rabbit. Fifty-two skeletally mature New Zealand White rabbits were used. Forty-two of the 52 operations were uneventful. Ten of the fifty-two developed complications, of which two were animal-related, and the other eight distractor-related. During the experiments the animals stayed healthy, and the distraction procedures were well tolerated. Rabbits are excellent for use in biological research on craniofacial distraction osteogenesis. Specifically, their nasal bones are easily accessible, the size and shape of the nasal bones allow various commercially available as well as custom-made distractors to be attached to the bones easily, their care and housing are relatively simple and inexpensive, and harvesting of tissue for further analyses is no problem because their skulls are of a manageable size and shape compared with other laboratory animals.

Significant reduction in neural adhesions after administration of the regenerating agent OTR4120, a synthetic glycosaminoglycan mimetic, after peripheral nerve injury in rats: Technical note (Article)

2008-11-01T00:00:00Z

Object. Extradural and intraneural scar formation after peripheral nerve injury frequently causes tethering and compression of the nerve as well as inhibition of axonal regeneration. Regenerating agents (RGTAs) mimic stabilizing and protective properties of sulphated glycosaminoglycan toward heparin-binding growth factors. The aim of this study was to assess the effect of an RGTA known as OTR4120 on extraneural fibrosis and axonal regeneration after crush injury in a rat sciatic nerve model. Methods. Thirty-two female Wistar rats underwent a standardized crush injury of the sciatic nerve. The animals were randomly allocated to RGTA treatment or sham treatment in a blinded design. To score neural adhesions, the force required to break the adhesions between the nerve and its surrounding tissue was measured 6 weeks after nerve crush injury. To assess axonal regeneration, magnetoneurographic measurements were performed after 5 weeks. Static footprint analysis was performed preoperatively and at Days 1, 7, 14, 17, 21, 24, 28, 35, and 42 postoperatively. Results. The magnetoneurographic data show no significant difference in conduction capacity between the RGTA and the control group. In addition, results of the static footprint analysis demonstrate no improved or accelerated recovery pattern. However, the mean pullout force of the RGTA group (67 ± 9 g [mean ± standard error of the mean]) was significantly (p < 0.001) lower than that of the control group (207 ± 14 g [mean ± standard error of the mean]). Conclusions. The RGTAs strongly reduce nerve adherence to surrounding tissue after nerve crush injury.

Ultrasound-guided near-nerve neurography for early evaluation of nerve regeneration (Article)

2008-09-30T00:00:00Z

For early assessment of axonal outgrowth after trauma, the nerve is surgically exposed to enable compound nerve action potential (CNAP) recordings across the lesion site. Near-nerve neurography, with needle electrodes placed transcutaneously near the nerve, could be a minimally invasive alternative if the needle placement procedure and low reproducibility are improved. We developed ultrasound-guided near-nerve neurography, which facilitates needle placement, and assessed its potential for evaluating nerve regeneration. Measurements were performed at varying times after crush lesion of the peroneal nerve of 25 rabbits. To test if ultrasound-guided near-nerve signals could be measured prior to muscle reinnervation, they were compared with recordings of compound muscle action potentials. A comparison with conventional intra-operative CNAP recordings was made by measuring nerve signal amplitude with both techniques and by assessing reproducibility. In all cases where intra-operative signals could be measured, near-nerve signals were also detected. Compound nerve activity could be recorded after 5 weeks, whereas compound muscle activity appeared after approximately 8 weeks. Reproducibility was slightly better for near-nerve than for intra-operative recordings. We conclude that ultrasound-guided near-nerve neurography is able to assess nerve regeneration well before compound muscle activity can be detected. Its accuracy and reproducibility are similar to those of conventional intra-operative recordings.

Single versus triple daily activation of the distractor: no significant effects of frequency of distraction on bone regenerate quantity and architecture (Article)

2008-04-01T00:00:00Z

OBJECTIVES: To study the effect of two different frequencies of distraction on the quantity and architecture of bone regenerate using micro-computed tomography, and to determine whether radiographic and ultrasonographic bone-fill scores provide reliable predictive value for the amount of new bone in the distraction area. MATERIAL AND METHODS: Twenty-six skeletally mature rabbits underwent three full days of latency, after which midface distraction was started. Low-frequency group (n=12): a distraction rate of 0.9 mm/d achieved by one daily activation for 11 days to create a 10mm distraction gap. High-frequency group (n=12): idem, but three daily activations were used instead of one. Control group (n=2) underwent no distraction. After 21 days of consolidation, bone-fill in the distraction area was assessed by means of ultrasonography and radiography. Micro-computed tomography was used to quantify new bone formation and bone architecture. RESULTS: Relative bone volume (BV/TV) showed a tendency towards a difference (P=0.09) between the low and high-frequency groups. No significant differences were found for bone architecture. No significant correlation between BV/TV values and bone-fill scores was found. CONCLUSIONS: An increase in rhythm from one to three activations daily does not create significantly more bone. Bone-fill score values provided no reliable predictive value for the amount of new bone formation.

RGTA OTR 4120, a heparan sulfate proteoglycan mimetic, increases wound breaking strength and vasodilatory capability in healing rat full-thickness excisional wounds (Article)

2008-03-01T00:00:00Z

ReGeneraTing Agents (RGTAs), a family of polymers engineered to protect and stabilize heparin-binding growth factors, have been shown to promote tissue repair and regeneration. In this study, the effects of one of these polymers, RGTA OTR4120, on healing of full-thickness excisional wounds in rats were investigated. Two 1.5 cm diameter circular full-thickness excisional wounds were created on the dorsum of a rat. After creation of the wounds, RGTA OTR4120 was applied. The progress of healing was assessed quantitatively by evaluating the wound closure rate, vasodilatory capability, and wound breaking strength. The results showed a triple increase of the local vascular response to heat provocation in the RGTA OTR4120-treated wounds as compared with vehicle-treated wounds. On days 14 and 79 after surgery, the wounds treated with RGTA OTR4120 gained skin strength 12% and 48% of the unwounded skin, respectively, and displayed a significantly increased gain in skin strength when compared with control animals. These results raise the possibility of efficacy of RGTA OTR4120 in accelerating surgically cutaneous wound healing by enhancing the wound breaking strength and improving the microcirculation.

3D surface imaging in medicine: A review of working principles and implications for imaging the unsedated child (Article)

2008-03-01T00:00:00Z

This article provides an overview of the methods used for optical surface imaging during the last 30 years, with the primary focus on the imaging of the unsedated child. The goal is to provide the reader with an overview of the working methods behind the published articles. This will enable the reader to better interpret current data and decide if a certain approach is suitable for their particular research question.

Recommendations for optimal distraction protocols for various animal models on the basis of a systematic review of the literature (Article)

2007-10-01T00:00:00Z

The principles of orthopaedic distraction osteogenesis (DO) have been successfully applied to the craniofacial skeleton, but the latency time, rate and rhythm of distraction, and length of the consolidation period that are optimal for long-bone distraction may be suboptimal for craniofacial DO. The aim of this study was to provide recommendations for optimal distraction parameters in animal experimental research on craniofacial DO. The data used were from studies, added to the PubMed database between 1 January 1973 and 1 January 2007, on the outcome of DO resulting from variations in a single distraction parameter while standardizing the other distraction parameters. Although experimental animal group sizes were rather small, especially in those studies that used large animals, and both skeletally mature and immature animals were used, the (in most cases quantitative) data provided useful information on the optimal parameters in craniofacial DO. A latency period may not be necessary at all. Distraction should be performed at a rate of 1mm/day (this may be halved when small animals such as rats are used) preferably with a continuous rhythm, followed by a consolidation period of 6-8 weeks. These recommendations can be used as basic guidelines for further animal experimental studies on craniofacial DO.

Administration of human insulin-like growth factor-binding protein-1 increases circulating levels of growth hormone in mice. (Article)

2004-09-01T00:00:00Z

GH is the major regulator of circulating IGF-I, which, in return, controls pituitary GH secretion by negative feedback. IGF-binding protein-1 (IGFBP-1) is believed to modify this feedback through its effects on free IGF-I. In the present study we investigated the potential influence of IGFBP-1 on GH secretion in the absence or presence of a GH receptor antagonist (GHRA) that specifically blocks peripheral GH action. We administered human (h) IGFBP-1 and GHRA to mice alone or in combination for 2 or 7 d. GHRA was administered in a dose previously shown to block GH action without an effect on circulating GH or IGF-I levels. hIGFBP-1 administration increased stimulated circulating GH levels and serum total IGF-I and IGFBP-3 levels. Coadministration of GHRA abolished the hIGFBP-1-induced increase in serum IGF-I and IGFBP-3 levels, whereas stimulated GH levels remained increased. Free IGF-I levels in serum were unchanged in all treatment groups. In conclusion, GH serum levels increased in response to hIGFBP-1 administration, even in the setting of normal IGF-I levels. This finding suggests a direct involvement of IGFBP-1 in GH secretion.

The role of the IGF axis in IGFBP-1 and IGF-I induced renal enlargement in Snell dwarf mice (Article)

2001-01-01T00:00:00Z

Insulin-like growth factor (IGF) binding protein-1 (IGFBP-1) is generally believed to inhibit IGF action in the circulation. In contrast, IGFBP-1 has been reported to interact with cell surfaces and enhance IGF-I action locally in some tissues. Renal IGFBP-1 levels are found elevated in various conditions characterized by renal growth (e.g. diabetes mellitus, hypokalemia). To test whether IGFBP-1 is a renotropic factor, IGFBP-1 was administered alone or in combination with IGF-I to Snell dwarf mice, an in vivo model without compensatory feedback effects on growth hormone (GH) secretion. In three control groups of Snell dwarf mice, placebo, GH or IGF-I was administered. Compared with placebo, kidney weight increased in all treated groups, however, with different effects on kidney morphology. Administration of IGF-I, alone or in combination with IGFBP-1, tended to increase glomerular volume, while no changes were seen in the other groups. Administration of IGFBP-1 or IGFBP-1+IGF-I both caused dilatation of the thin limbs of Henle's loop, while GH or IGF-I administration had no visible effect. Furthermore, IGF-I administration resulted in an increased mean number of nuclei per cortical area and renal weight, whereas GH, IGF-I+IGFBP-1 or IGFBP-1 caused a decreased renal nuclei number. In situ hybridization and immunohistochemistry showed specific changes of the renal IGF system expression patterns in the different groups. Particularly, IGFBP-1 administration resulted in extensive changes in the mRNA expression of the renal IGF system, whereas the other administration regimen resulted in less prominent modifications. In contrast, administration of IGFBP-1 and IGFBP-1+IGF-I resulted in identical changes in the protein expression of the renal IGF system. Our results indicate that IGFBP-1, alone or in combination with IGF-I, demonstrated effects on the renal tubular system that differ from the effects of IGF-I.

Dose-response effects of a new growth hormone receptor antagonist (B2036-PEG) on circulating, hepatic and renal expression of the growth hormone/insulin-like growth factor system in adult mice (Article)

2000-01-01T00:00:00Z

The effects of growth hormone (GH) in regulating the expression of the hepatic and renal GH and insulin-like growth factor (IGF) system were studied by administering a novel GH receptor antagonist (GHRA) (B2036-PEG) at different doses (0, 1.25, 2.5, 5 and 10 mg/kg/day) to mice for 7 days. No differences were observed in the groups with respect to body weight, food consumption or blood glucose. However, a dose-dependent decrease was observed in circulating IGF-I levels and in hepatic and renal IGF-I levels at the highest doses. In contrast, in the 5 and 10 mg/kg/day GHRA groups, circulating and hepatic transcriptional IGF binding protein-3 (IGFBP-3) levels were not modified, likely resulting in a significantly decreased IGF-I/IGFBP-3 ratio. Hepatic GH receptor (GHR) and GH binding protein (GHBP) mRNA levels increased significantly in all GHRA dosage groups. Endogenous circulatory GH levels increased significantly in the 2.5 and 5 mg/kg/day GHRA groups. Remarkably, increased circulating IGFBP-4 and hepatic IGFBP-4 mRNA levels were observed in all GHRA administration groups. Renal GHR and GHBP mRNA levels were not modified by GHRA administration at the highest doses. Also, renal IGFBP-3 mRNA levels remained unchanged in most GHRA administration groups, whereas IGFBP-1, -4 and -5 mRNA levels were significantly increased in the 5 and 10 mg/kg/day GHRA administration groups. In conclusion, the effects of a specific GHR blockade on circulating, hepatic and renal GH/IGF axis reported here, may prove useful in the future clinical use of GHRAs.

The effect of epidermal growth factor and IGF-I infusion on hepatic and renal expression of the IGF-system in adult female rats (Article)

2000-01-01T00:00:00Z

Systemic administration of epidermal growth factor (EGF) in neonatal rats results in reduced body weight gain and decreased circulating levels of IGF-I, suggesting its involvement in EGF-induced growth retardation. We investigated the effect of EGF and/or IGF-I administration for 7 days on circulating IGF-I and IGFBP levels and hepatic and renal IGF-system mRNA expression profiles in adult female rats. EGF administration (30 microg/rat/day) did not influence body weight, liver or kidney weight. In contrast, IGF-I (400 microg/rat/day) and EGF/IGF-I administration increased both body weight and kidney weight. Also, serum IGF-I and the 30 kDa IGFBPs (IGFBP-1 and -2) were significantly increased in these groups. Serum IGFBP-3 levels increased in the IGF-I group along with increased hepatic IGFBP-1 and -3 mRNA levels. In contrast, in the EGF administration group serum IGFBP-3 levels were significantly decreased; however, the mRNA levels remained unchanged. In the EGF/IGF-I administration group, serum IGF-I and IGFBP-3 levels were significantly lowered when compared with the IGF-I administration group. This was in contrast to the effect on kidney weight increase that was identical for the IGF-I and EGF/IGF-I groups. The decrease in serum IGFBP-3 was not reflected at the hepatic IGFBP-3 mRNA level. IGFBP-3 expression might be regulated at a post-transcriptional level although EGF induced IGFBP-3 proteolysis could not be demonstrated in vitro. We conclude that EGF administration reduced serum IGFBP-3 whereas IGF-I administration increased the level of IGFBP-3 and IGF-I and resulted in an increased body and kidney weight in adult female rats.

Generation of antisera to mouse insulin-like growth factor binding proteins (IGFBP)-1 to -6: comparison of IGFBP protein and messenger ribonucleic acid localization in the mouse embryo (Article)

1999-01-01T00:00:00Z

The insulin-like growth factor (IGF) system is an important regulator of fetal growth and differentiation. IGF bioavailability is modulated by IGF binding proteins (IGFBPs). We have generated six different antisera, directed to synthetic peptide fragments of mouse IGFBP-1 through -6. The specificity of the produced antisera was demonstrated by enzyme-linked immunosorbent assay, Western blotting, and by immunohistochemistry on sections of mouse embryos of 13.5 days post coitum. Specificity for the IGFBP-2 through -6 antisera also was confirmed immunohistochemically in liver and lung of corresponding gene deletion (knock-out) mutant mice and wild-type litter mates. Immunohistochemistry and messenger RNA (mRNA) in situ hybridization on sections of mouse embryos of 13.5 days post coitum revealed tissue-specific expression patterns for the six IGFBPs. The only site of IGFBP-1 protein and mRNA production was the liver. IGFBP-2, -4, and -5 protein and mRNA were detected in various organs and tissues. IGFBP-3 and -6 protein and mRNA levels were low. In several tissues, such as lung, liver, kidney, and tongue, more than one IGFBP (protein and mRNA) could be detected. Differences between mRNA and protein localization were extensive for IGFBP-3, -5, and -6, suggesting that these IGFBPs are secreted and transported. These results confirm the different spatial localization of the IGFBPs, on the mRNA and protein level. The overlapping mRNA and protein localization for IGFBP-2 and -4, on the other hand, may indicate that these IGFBPs also function in an auto- or paracrine manner.