1,354,331 research outputs found
Peripheral Nerve Regeneration by Artificial Nerve Guides
No full textIt is more than 20 years since artificial nerve guides (or conduits) were introduced into clinical practice as a reliable alternative to autograft. They are basically cylindrical conduits inside which a regenerating nerve stump may find protection and guidance. Early guides were made of silicone and were not biodegradable; they were shown to support nerve regeneration but, subsequently, were considered responsible for stenosis of the regenerated nerve in several instances, which required their removal. Degradable guides have been proposed and are now widely used. An overview of the clinical outcome of artificial nerve guides in peripheral nerve-gap injuries has shown that they perform at least as well as autografts in gaps that are no longer than 20 mm, bringing the significant advantage of avoiding donor site sacrifice and morbidity. The present knowledge and limitations of contemporary nerve guides are illustrated; research to improve the present designs is discussed. © 2009 Springer-Verlag Milan
Transmission electron microscopy of Ledderhose disease in a patient with bilateral presentation
No full textThe plantar fibromatosis of the foot, also known as Ledderhose Disease, presents itself as one or more rounded, firm, hard nodules, typically located on the medial side of the plantar vault. The etiology is unknown but Ledderhose Disease is correlated with the Dupytren contracture and Peyronie's Disease, as they are all fibroproliferative disorders. The lack of significant literature for Transmission Electron Microscopy (TEM) of Ledderhose Disease, prompted us to perform an extensive TEM analysis in a case of bilateral presentation, in a Caucasian male of 31 years of age. We confirmed the morphological similarities among these three diseases. A highly disordered assembly of collagen fibers was documented together with the morphological characters of myofibroblasts for the cell population. Presence of giant cells and possibly mast-cells was notable, but their role and relevance are matter for speculation because of the allergic diathesis of the patient. The specific history of the patient seems to exclude that a recurrent external mechanical stress was the causative action, because it was applied only on one side in an otherwise bilateral presentation. A recommendation is made to every clinician to be aware of Ledderhose Disease and to provide an early diagnosis. In case surgery is required, it should be an accurate micro-surgical excision to be performed in a qualified center
Reciprocal nerve staining (RNS) for the concurrent detection of choline acetyltransferase and myelin basic protein on paraffin-embedded sections
No full textBackground: Objective of our work was to develop a sequential double nonfluorescent immunostaining method which allows the selective identification of myelinated motor fibers in paraffin-embedded samples of peripheral nerves. Motor recovery after a nerve gap-lesion repaired by artificial nerve-guides (“conduits”) is often less complete and slower than sensory recovery. The mechanism for this is not fully understood. New method: Incubation in sheep polyclonal choline acetyltransferase antibody (Abcam 18,736) at dilution of 1:150 was followed by incubation in mouse monoclonal anti-myelin basic protein antibody (Abcam 62,631) at a dilution of 1:5000. Counterstaining was performed with hematoxylin QS (Vector Labs H-3404). Results: Immunostaining of choline acetyltransferase and myelin basic protein can be combined together and results show a good contrast between the light brown of the choline acetyltransferase reaction product and the green of myelin basic protein reaction product. Cell nuclei are stained blue. This new protocol retains the advantages of paraffin embedded sections such as (i) having a relatively simple methodology, (ii) years-long storage life, and (iii) easy sharing among laboratories. Comparison with existing method. This specific combinatorial protocol has never been used before on paraffin embedded sections. It has been named “reciprocal nerve staining” (RNS). Conclusions: Routine combination of choline acetyltransferase and myelin basic protein immunostaining provides a highly specific, highly contrasted paraffin-embedded sections where optical differentiation of myelinated motor fibers is easy and straightforward. This method will likely simplify and speed-up the routine histological study of nerve regeneration and will contribute a better identification of the nerve motor component
Plantar pressure distribution in patients with neuropathic diabetic foot
No full textPurpose: To describe the plantar pressure distribution in a selected group of patients with diabetic foot and to highlight their alterations in gait cycle, which follow the involvement of the foot in systemic diabetic neuropathy. Methods: Ten patients with diabetic foot due to insulin dependent diabetes mellitus (IDDM) were studied. Gait cycle kinematics were video-recorded, both in frontal (AP view) and in sagittal (LL view) planes. Plantar pressure measurements+ APview+LLview were synchronized and compared to a computer-graphic generated skeletal model of the foot. Results: In diabetic neuropathic patients, there was a prolonged interval between heel strike and toe-off with respect to normal controls. A limited motion, quite close to frank rigidity, affecting the mid-tarsal, sub-talar and ankle joints was noted. There was an early transfer of load from rear to front-foot. Shear stresses appeared. Metatarsal heads were over-loaded both in magnitude and in time. Areas of over-load present in the static plantar pressure measurement correlated poorly with areas of overload in dynamic plantar pressure measurement and areas where ulceration was present. Conclusion: Prolonged duration of the gait cycle and shear stresses characterize the plantar pressure pattern of diabetic neuropathic patients. Furthermore, results suggest that static plantar pressure measurement has no clinical correlation with areas where ulcerations are present. © Società Italiana Biomateriali
A suspended carbon fiber culture to model myelination by human Schwann cells
No full textAbstract: Understanding of myelination/remyelination process is essential to guide tissue engineering for nerve regeneration. In vitro models currently used are limited to cell population studies and cannot easily identify individual cell contribution to the process. We established a novel model to study the contribution of human Schwann cells to the myelination process. The model avoids the presence of neurons in culture; Schwann cells respond solely to the biophysical properties of an artificial axon. The model uses a single carbon fiber suspended in culture media far from the floor of the well. The fiber provides an elongated structure of defined diameter with 360-degree of surface available for human Schwann cells to wrap around. This model enabled us to spatially and temporally track the myelination by individual Schwann cells along the fiber. We observed cell attachment, elongation and wrapping over a period of 9 days. Cells remained alive and expressed Myelin Basic Protein and Myelin Associated Glycoprotein as expected. Natural and artificial molecules, and external physical factors (e.g., p atterned electrical impulses), may be tested with this model as possible regulators of myelination. Graphical Abstract: [InlineMediaObject not available: see fulltext.
Can we regrow a human arm? A negative perspective from an upper-limb surgeon
No full textIf we would like to devote time and money to the task of regrowing a human arm, we should feel free to do it, in principle. However, if we recognize a purpose in biomedical research, we must scrutinize this task in the light of a possible clinical application. We will then discover that regrowing a human arm is not only likely to be not possible, but also not required in the clinic. Bionic arms and better reconstructive surgery already provide a different, simpler and easier solution to the loss of a human arm, and should be promoted. Probably, "can we regrow a human arm?" is not the right question. Instead, we should ask, "can we restore the function of a lost human arm?"
A modified spica-splint in postoperative early-motion management of skier's thumb lesion: a randomized clinical trial
No full textBackground: Rupture of ulnar collateral ligament of the thumb (UCL) represents a frequent injury of the hand. Surgical repair is considered the gold standard but postoperative immobilization causes partial stiffness in a percentage of cases. Aim: The aim of this paper was to assess the effectiveness of a postoperative functional hand-based splint for the thumb which allows immediate postoperative motion. Design: Randomized prospective clinical trial. Setting. The study was carried out at the Orthopedics and Hand Surgery Unit of The Catholic University School of Medicine, Rome, Italy. Population: Thirty consecutive patients, with a diagnosis of acute complete tear of the UCL, were selected to be treated surgically (predominantly men, mean age 39). Cases presenting associated injuries were not included. Methods: Patients were randomized postoperatively into 2 groups of 15 (one using the new splint and the other using a standard spica splint). After four weeks of splinting, clinical outpatient evaluations were carried on (at one, two, six, twelve months) on both groups to evaluate: joint stability; pain; pinch strength; range of motion; time lost from work; sessions of physiotherapy. Results: Immediate postoperative motion of the operated joint produced faster and better functional results. No cases of recurrence were recorded. Conclusions: Surgical repair, combined with active metacarpophalangeal motion allowed by the new functional splint, was effective, safe and well tolerated. Clinical rehabilitation impact: Enhancing the patients' function and reducing the time of functional recovery, the reported treatment presents potential advantages in the management of this frequent acute hand injury
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