During the Early Stages of Staphylococcus aureus Biofilm Formation, Induced Neutrophil Extracellular Traps Are Degraded by Autologous Thermonuclease.

Staphylococcus aureus extracellular DNA (eDNA) plays a crucial role in the structural stability of biofilms during bacterial colonization; on the contrary, host immune responses can be induced by bacterial eDNA. Previously, we observed production of S. aureus thermonuclease during the early stages of biofilm formation in a mammalian cell culture medium. Using a fluorescence resonance energy transfer (FRET)-based assay, we detected thermonuclease activity of S. aureus biofilms grown in Iscove's modified Dulbecco's medium (IMDM) earlier than that of widely studied biofilms grown in tryptic soy broth (TSB). The thermonuclease found was Nuc1, confirmed by mass spectrometry and competitive Luminex assay. These results indicate that biofilm development in IMDM may not rely on eDNA for structural stability. A bacterial viability assay in combination with wheat germ agglutinin (WGA) staining confirmed the accumulation of dead cells and eDNA in biofilms grown in TSB. However, in biofilms grown in IMDM, minimal amounts of eDNA were found; instead, polysaccharide intercellular adhesin (PIA) was detected. To investigate if this early production of thermonuclease plays a role in immune modulation by biofilm, we studied the effect of thermonuclease on human neutrophil extracellular trap (NET) formation using a nuc knockout and complemented strain. We confirmed that thermonuclease produced by early-stage biofilms grown in IMDM degraded biofilm-induced NETs. Additionally, neither the presence of biofilms nor thermonuclease stimulated an increase in reactive oxygen species (ROS) production by neutrophils. Our findings indicated that S. aureus, during the early stages of biofilm formation, actively evades the host immune responses by producing thermonuclease.

Development of grading scales of pedal sensory loss using Mokken scale analysis on the Rotterdam Diabetic Foot Study Test Battery data.

INTRODUCTION: Loss of sensation due to diabetes-related neuropathy often leads to diabetic foot ulceration. Several test instruments are used to assess sensation, such as static and moving 2-point discrimination (S2PD, M2PD), monofilaments, and tuning forks. METHODS: Mokken scale analysis was applied to the Rotterdam Diabetic Foot Study data to select hierarchies of tests to construct measurement scales. RESULTS: We developed 39-item and 31-item scales to measure loss of sensation for research purposes and a 13-item scale for clinical practice. All instruments were strongly scalable and reliable. The 39 items can be classified into 5 hierarchically ordered core clusters: S2PD, M2PD, vibration sense, monofilaments, and prior ulcer or amputation. DISCUSSION: Guided by the presented scales, clinicians may better classify the grade of sensory loss in diabetic patients' feet. Thus, a more personalized approach concerning individual recommendations, intervention strategies, and patient information may be applied.

Outcome predictors for wound healing in patients with a diabetic foot ulcer.

The aim of this study was to identify diabetic foot ulcer (DFU) patients at risk for the development of a hard-to-heal wound. This is a post-hoc analysis of a prospective cohort study including a total of 208 patients with a DFU. The primary endpoints were time to healing and the development of a hard-to-heal-wound. Univariable and multivariable logistic and Cox regression analysis were used to study the associations of patient characteristics with the primary endpoints. The number of previous DFUs [odds ratio (OR): 1.42, 95% confidence interval (CI): 1.01-1.99, P = .04], University of Texas (UT) classification grade 2 (OR: 2.93, 95% CI: 1.27-6.72, P = .01), UT classification grade 3 (OR: 2.80, 95% CI: 1.17-6.71, P = .02), and a diagnosis of foot stand deformation (OR: 1.54, 95% CI: 0.77-3.08, P = .05) were significantly associated with the development of a hard-to-heal wound. Only UT classification grade 3 (HR: 0.61, 95% CI: 0.41-0.90, P = .01) was associated with time to healing. The number of previous DFUs, UT classification grade, and a diagnosis of foot deformation are significantly associated with development of a hard-to-heal wound in patients with a DFU. The only predictor significantly associated with time to healing was UT classification grade 3. These patient characteristics can be used to identify patients at risk for the development of hard-to-heal wounds, who might need an early intervention to prevent wound problems.

Grading the loss of sensation in diabetic patients: A psychometric evaluation of the rotterdam diabetic foot study test battery.

INTRODUCTION: Static- and moving 2-point discrimination (S2PD, M2PD), 10-g monofilaments- and tuning fork are validated outcome measures of clinical manifestations of diabetes-related neuropathy. No modern statistical techniques have been used to investigate how well these instruments combine to measure sensory loss. METHODS: To grade sensory loss at the feet, we fitted parametric forms of Item Response Theory models to the data of these instruments. RESULTS: The fit statistics indicate that the loss of sensation is gradable, with readily available instruments. S2PD and M2PD are lost first, followed by vibration sense, the 10-g monofilament and the ability to feel a cold stimulus. CONCLUSIONS: This test battery appears to provide sound measurement properties in a group of diabetic patients with diverse amounts of sensory loss. This approach may be used in clinical practice to grade sensory loss reliably and quickly, with instruments that are easy to use. Muscle Nerve 58: 559-565, 2018.

Nerve reinnervation and itch behavior in a rat burn wound model.

In this study, we investigated whether postburn itch in rats, after a full thickness burn, is correlated to the nervous reinnervation of the burn wound area. For this purpose, we determined scratching duration (expressed as second/hour) at 24 hours, 2, 4, 8, and 12 weeks postburn and combined this with immunohistochemistry for protein gene product 9.5 (PGP9.5) to identify all nerve fibers, calcitonin gene related peptide (CGRP) to identify peptidergic fibers, tyrosine hydroxylase (TH) for sympathetic fibers, and growth-associated protein 43 (GAP-43) for regrowing fibers. We found a modest, but highly significant, increase in scratching duration of all burn wound rats from 3 to 12 weeks postburn (maximally 63 ± 9.5 second/hour compared to sham 3.1 ± 1.4 second/hour at 9 weeks). At 24 hours postburn, all nerve fibers had disappeared from the burn area. Around 4 weeks postburn PGP 9.5- and CGRP-immunoreactive nerve fibers returned to control levels. TH- and GAP-43-IR nerve fibers, which we found to be almost completely colocalized, did not regrow. No correlation was found between scratching duration and nervous reinnervation of the skin. The present results suggest that in rat, like in human, burn wound healing will induce increased scratching, which is not correlated to the appearance of nervous reinnervation.

Normative data for cutaneous threshold and spatial discrimination in the feet.

INTRODUCTION: No data are available for normative values of cutaneous threshold and spatial discrimination in the feet. We developed clinically applicable reference values in relation to the nerve distributions of the feet. METHODS: We determined foot sensation in 196 healthy individuals. Cutaneous threshold (1-point static discrimination, S1PD) was tested with monofilaments (0.008 to 300 gram) and spatial discrimination (2-point static [S2PD] and moving [M2PD] discrimination) on five locations per foot. RESULTS: There was a significant age-dependent increase in S1PD, S2PD, and M2PD values (P < 0.05). No significant differences were found between both feet. S1PD values differed up to 0.8 g between genders. There were no significant differences between genders for S2PD and M2PD measurements. M2PD values were generally lower than S2PD values. CONCLUSIONS: This study provides age-related normative values for foot sensation to help clinicians assess sensory deficits in relation to aging and identify patients with underlying nerve problems. Muscle Nerve 56: 399-407, 2017.

Metric properties of advanced imaging methods in osteoarthritis of the hand: a systematic review.

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.

The clinical applicability of sensor technology with body position detection to combat pressure ulcers in bedridden patients.

INTRODUCTION: Pressure Ulcers (PUs) are a major healthcare issue leading to prolonged hospital stays and decreased quality of life. Monitoring body position changes using sensors could reduce workload, improve turn compliance and decrease PU incidence. METHOD: This systematic review assessed the clinical applicability of different sensor types capable of in-bed body position detection. RESULTS: We included 39 articles. Inertial sensors were most commonly used (n = 14). This sensor type has high accuracy and is equipped with a 2-4 hour turn-interval warning system increasing turn compliance. The second-largest group were piezoresistive (pressure) sensors (n = 12), followed by load sensors (n = 4), piezoelectric sensors (n = 3), radio wave-based sensors (n = 3) and capacitive sensors (n = 3). All sensor types except inertial sensors showed a large variety in the type and number of detected body positions. However, clinically relevant position changes such as trunk rotation and head of bed elevation were not detected or tested. CONCLUSION: Inertial sensors are the benchmark sensor type regarding accuracy and clinical applicability but these sensors have direct patient contact and (re)applying the sensors requires the effort of a nurse. Other sensor types without these disadvantages should be further investigated and developed. We propose the Pressure Ulcer Position System (PUPS) guideline to facilitate this.

Computed tomography for the detection of thumb base osteoarthritis: comparison with digital radiography.

OBJECTIVE: To compare computed tomography (CT) with digital radiography for the detection of osteoarthritis (OA) of the first carpometacarpal (CMC1) and scaphotrapeziotrapezoid (STT) joint. MATERIALS AND METHODS: We retrospectively identified patients who were assessed for CMC1 OA or STT OA at our hand surgery outpatient clinic between January 2008 and March 2011, and who had both a digital radiograph and a CT scan of the hand within a 3-month period. CT and radiographic images were scored independently by two musculoskeletal radiologists for joint space narrowing (JSN), osteophytes, subchondral sclerosis, bone cysts, and erosions in the CMC1 and STT joints. RESULTS: Thirty patients were identified. The inter-reader reliability of CT for the detection of CMC1 OA (ICC 1.00) and STT OA (ICC 0.80) was higher than radiography (ICC's 0.15 and 0.45). In comparison with their own radiographical scoring, both readers detected with CT 3 more patients with CMC1 OA, and 13 and 5 more patients with STT OA. CONCLUSION: Computed tomography had a higher inter-reader reliability and detection rate for both CMC1 and STT OA, compared with radiography. As surgical treatment selection of thumb base OA depends on the presence of pathology in the CMC1 and STT joints, CT may improve treatment selection and surgical planning.

Characterization of a three-dimensional mucosal equivalent: similarities and differences with native oral mucosa.

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 ß4 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.

The effects of heparan sulphate mimetic RGTA-OTR4120 on irradiated murine salivary glands.

BACKGROUND: This study focuses on the potential of ReGeneraTing Agent OTR4120 (RGTA-OTR4120) to treat radiation-induced damage of salivary glands. RGTAs are biopolymers designed to mimic the effects of heparan sulphate, thereby stimulation tissue repair and regeneration. METHODS: C3H mice were irradiated with a single dose of 15 Gy in the head and neck region. RGTA-OTR4120 was injected 24 h after radiotherapy, followed by weekly injections. At 2, 6 and 10 weeks after radiotherapy, salivary flow rates were measured and animals were sacrificed to obtain parotid and submandibular glands for histology. Periodic acid Schiff stain was performed to visualize mucins that are produced by acinar cells. Amylase and total protein content were measured in saliva samples. RESULTS: Salivary flow rates were increased at 2 weeks, but not at 6 and 10 weeks after radiotherapy with RGTA-OTR4120 administration, compared to irradiated controls. Two and 10 weeks after radiotherapy, the mucin production activity of acinar cells was increased under influence of RGTA administration. RGTA-OTR4120 did not influence amylase or total protein secretion. CONCLUSION: RGTA-OTR4120 administration has a positive effect on salivary flow rates in irradiated mice on the short term. The effect was absent 10 weeks after radiotherapy, while at that time point, mucin producing activity of acinar cells was elevated by RGTA-OTR4120 administration. Given these results and the advantages of RGTA use in irradiated patients, further investigation on the potential of this drug to treat radiation-induced salivary gland damage, alone or in combination with other drugs, such as amifostine, is suggested.

Microfluidic evidence of synergistic effects between mesenchymal stromal cell-derived biochemical factors and biomechanical forces to control endothelial cell function.

A functional vascular system is a prerequisite for bone repair as disturbed angiogenesis often causes non-union. Paracrine factors released from human bone marrow derived mesenchymal stromal cells (BMSCs) have angiogenic effects on endothelial cells. However, whether these paracrine factors participate in blood flow dynamics within bone capillaries remains poorly understood. Here, we used two different microfluidic designs to investigate critical steps during angiogenesis and found pronounced effects of endothelial cell proliferation as well as chemotactic and mechanotactic migration induced by BMSC conditioned medium (CM). The application of BMSC-CM in dynamic cultures demonstrates that bioactive factors in combination with fluidic flow-induced biomechanical signals significantly enhanced endothelial cell migration. Transcriptional analyses of endothelial cells demonstrate the induction of a unique gene expression profile related to tricarboxylic acid cycle and energy metabolism by the combination of BMSC-CM factors and shear stress, which opens an interesting avenue to explore during fracture healing. Our results stress the importance of in vivo - like microenvironments simultaneously including biochemical, biomechanical and oxygen levels when investigating key events during vessel repair. STATEMENT OF SIGNIFICANCE: Our results demonstrate the importance of recapitulating in vivo - like microenvironments when investigating key events during vessel repair. Endothelial cells exhibit enhanced angiogenesis characteristics when simultaneous exposing them to hMSC-CM, mechanical forces and biochemical signals simultaneously. The improved angiogenesis may not only result from the direct effect of growth factors, but also by reprogramming of endothelial cell metabolism. Moreover, with this model we demonstrated a synergistic impact of mechanical forces and biochemical factors on endothelial cell behavior and the expression of genes involved in the TCA cycle and energy metabolism, which opens an interesting new avenue to stimulate angiogenesis during fracture healing.

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

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.

Histological validation of ultrasound-guided neurography in early nerve regeneration.

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 microm, 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.

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

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.

Sensory testing of inferior alveolar nerve injuries: a review of methods used in prospective studies.

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.

Cold intolerance in surgically treated neuroma patients: a prospective follow-up study.

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.

Balance, risk of falls, risk factors and fall-related costs in individuals with diabetes.

AIMS: Sensory loss and impaired balance are considered risk factors of incident falls. The aim of this study was to assess the relationship between degree of foot sensation and balance, risk of falls, incidence of fall-related injuries and costs in a cohort of patients with diabetes. METHODS: (Non)-neuropathic subjects participating in the Rotterdam Diabetic Foot Study were followed prospectively. Subjects underwent sensory testing of the feet (39 item Rotterdam Diabetic Foot Study Test Battery (RDF-39)); balance was assessed at the second follow-up (Brief-BESTest) as were data on incident falls. Medical records and financial data were abstracted to estimate fall-related morbidity and in-hospital costs. RESULTS: A higher RDF-39 score, cerebral artery disease, type 2 diabetes, height and age were predictors of the Brief-BESTest total score. 41/296 patients (13.9%) reported two or more falls during follow-up. Predictors for recurrent falls were a higher RDF-39 score (aOR: 1.124, p < 0.0005), male gender (aOR: 0.319, p = 0.016), age (aOR: 0.938, p = 0.003) and type 2 diabetes (aOR: 3.157, p = 0.100). Thirty-one patients used medical resources (median US$ 440.45 (IQR: 179-1162). CONCLUSIONS: Degree of sensory loss correlates significantly with an increased imbalance and risk of falls. The RDF-39 may be used as stratification tool in medical decision-making and patient information.

Ultrasound-guided near-nerve neurography for early evaluation of nerve regeneration.

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.

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

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.