Simulation dataset of thermal and epithermal neutron self-shielding correction factors for 186W(n,γ)187W reaction rate experiments using tungsten foil targets.

In the experiments of neutron interaction with research samples, the incident neutron energy spectrum, distribution inside the irradiating sample volume, is affected by the unexpected neutron self-shielding effects. The nature of these effects is due to the formation and thickness of the irradiating sample, which significantly causes neutron self-absorption and multiple scattering inside the sample volume. The datasets presented in this article showed the thermal (Gth) and epithermal (Gepi) neutron self-shielding correction factors for the 186W(n,γ)187W neutron capture reaction rate in irradiating tungsten (W) foil samples with different thicknesses. The simulations were performed for three models of surface neutron source's geometries and relative orientations of the irradiating foil samples of isotropic cylinder surface neutron source with foil sample along to the center line, isotropic cylinder neutron source with foil sample flat to the center line, and isotropic spherical neutron source with foil sample placed at the center point. The range of sample thicknesses was from 10 µm to 2.5 mm. The uncertainties for each data point are also reported in the data table, making it more convenient for reuse in related experiments or evaluations.

Early Recurrent Carpal Tunnel Syndrome in Patients with Mucopolysaccharidoses.

Early-onset carpal tunnel syndrome (CTS) is a well-known manifestation of mucopolysaccharidoses (MPS) due to excessive deposition of glycosaminoglycans in soft tissues. Standard treatment has been carpal tunnel release surgery, with the conventional technique of dividing the transverse carpal ligament. With advancement of treatments for MPS, these patients now have a longer life expectancy and are presenting with recurrent CTS. Management of recurrent CTS in these patients is not well studied. Here, we report 2 cases of recurrent CTS in MPS patients after a carpal tunnel release operation. We describe the findings on repeat operations and propose a unique technique for treating CTS in MPS patients to minimize recurrence during the initial CTS surgery. Our method involves resection of a portion of the transverse carpal ligament and use of a hypothenar fat pad flap over the median nerve.

Congenital Pseudoarthrosis of the Distal Radius Treated With Physeal-Sparing Double-Barrel Vascularized Free Fibula Transfer: A Case Report.

BACKGROUND: Neurofibromatosis type 1 is a hereditary disease that can lead to pseudoarthrosis of various long bones. Rarely, pseudoarthrosis affects the forearm, and to the best of our knowledge, this is the first reported case of pseudarthrosis of the distal radius treated by this unique method. METHODS: We present a case of a 7-year-old male who underwent multiple operations to treat pseudoarthrosis of the distal radius. RESULTS: After failed conservative and operative fixation augmented with autologous iliac crest bone grafting, the patient underwent a successful double-barrel vascularized free fibula graft while preserving the physis of the distal radius. CONCLUSION: Double-barrel vascularized free fibula bone graft can be successfully used as the definitive treatment in refractory cases of distal forearm pseudarthrosis and we believe that our technique can be applied to all cases of pseudarthrosis in other patients with a similar presentation and lesion location.

Multiple costimulatory blockade in the peripheral nerve allograft.

BACKGROUND: In the nerve allograft model, costimulation blockade has permitted good regeneration but is still inferior to the nerve isograft. We hypothesize that a short course of multiple costimulatory pathway blockade will be more effective in inhibiting the redundancy of the immune response and improve nerve regeneration through the nerve allograft. METHODS: The murine sciatic nerve allograft model was used to reconstruct a 1 cm sciatic nerve gap. Treatment consisted of the inhibition of the CD40, CD28/B7 and ICOS pathways and was compared with only single or double costimulation blockade. Assessment methods included quantitative histomorphometry and ELISPOT assay to quantify the host immune response after 3 weeks post-operatively. RESULTS: Triple costimulation blockade permitted regeneration through the nerve allograft that was equivalent to the nerve isograft. A short course of three doses was more effective than a single dose for all combinations tested. ELISPOT assay demonstrated minimal in vitro immune response with a short course of double or triple pathway-blocking agents. CONCLUSION: Costimulation blockade, especially with the simultaneous inhibition of multiple pathways, remains a promising strategy to promote regeneration through the peripheral nerve allograft, and may be uniquely suited to the temporary immunosuppressive requirements of the peripheral nerve allograft.

Production of a novel fibroblast-populated platelet matrix cocultured with keratinocytes.

We have developed a new method for the production of a dermal matrix equivalent. Human platelets were used to dilute human fibroblasts. The platelet mix was placed in a cell culture well. Addition of 200 microL of a thrombin solution caused gel formation. Gels were overlaid with standard Iscove's growth medium supplemented with 10% fetal bovine serum, insulin, and N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid buffer. Medium was exchanged regularly. Keratinocytes were plated on top of selected gels and elevated to the air-liquid interface. The gels were harvested weekly, fixed, cut, and stained with hematoxylin and eosin stains and immunostains for collagens I, III, and IV and cytokeratins. Digital image analysis was used to quantitate collagen production. Growth factors, including transforming growth factor-beta (TGF-beta), platelet-derived growth factor, and vitamin C were added. Staining identified fibroblasts within the gels with a surrounding fibrous matrix. Immunostaining for cytokeratin identified keratinocytes on the gel surface. Immunostaining revealed the fibrous matrix to be composed of collagen I and III and some collagen IV. Digital image analysis demonstrated that greater TGF-beta concentration resulted in greater collagen production. These differences were statistically significant. With development of this construct, a viable dermal/epidermal replacement may be possible. TGF-beta enhances collagen production by fibroblasts in this matrix.

Review of vascularized bone marrow transplantation: current status and future clinical applications.

In this review, we examine the applicability of the vascularized bone marrow transplant (VBMT) as an alternative to conventional bone marrow transplantation (BMT). As a new surgical approach, the VBMT is unique by transplantation of the stromal environment that eliminates the need for an engraftment period, provides critical signaling and modulatory functions, and may potentiate tolerance induction. Thus far, VBMT studies have demonstrated an absence of graft-versus-host disease (GVHD) and robust engraftment into nonmanipulated as well as irradiated recipients with evidence of immunological tolerance. Further investigation is needed to determine the applicability of VBMT as an alternative to BMT.

Surgical options for facial reanimation.

Facial palsy has devastating functional and psychosocial sequelae for patients, thus its treatment requires thorough understanding of state-of-the-art modalities that can optimize facial reanimation. Treatment depends on the mechanism and timing of injury, patient goals, overall health, and motivation. Because of its significant impact on patient's quality of life, both acute and long-standing deficits should be addressed. Often requiring multi-disciplinary efforts, an institution well-equipped in dealing with facial reanimation offers patients the most consistent results.

Lymphadenectomy prior to rat hind limb allotransplantation prevents graft-versus-host disease in chimeric hosts.

In previous rat studies, the use of mixed allogeneic chimerism (MAC) to induce host tolerance to hind limb allografts has resulted in severe graft-versus-host disease (GVHD). The purpose of this study was to determine if immunocompetent cells in bone marrow (BM) and/or lymph nodes (LNs) of transplanted limbs were responsible for inducing GVHD in mixed chimeric hosts. [ACI-->Wistar Furth] chimeric rats received ACI hind limbs that were non-irradiated, irradiated (1050 cGy) or lymphadenectomized. Rejection, GVHD and donor chimerism was assessed. Chimeric hosts rejected none of their limbs. However, hosts of non-irradiated hind limbs succumbed to GVHD 22.4+/-0.8 days after transplantation. In contrast, chimeras that received irradiated or lymphadenectomized ACI hind limbs showed no clinical or histological signs of GVHD at 5 months. We conclude that mixed chimeric hosts are susceptible to GVHD due to the immunocompetent cell load provided by the LNs, not the BM, of hind limb allografts.

A case of warfarin skin necrosis despite enoxaparin anticoagulation in a patient with protein S deficiency.

Warfarin-induced skin necrosis is a rare complication associated with the use of oral anticoagulants. Most patients develop this at the initiation of therapy, often while still receiving intravenous unfractionated heparin (UFH). Recently, low-molecular-weight heparins (LMWHs) have gained wider use, providing an option for outpatient treatment of deep-vein thrombosis. The treatment protocols are similar to UFH, including the early initiation of oral anticoagulation with warfarin. A Medline search failed to reveal any cases of warfarin-induced skin necrosis while using a LMWH. We present a patient with protein S deficiency who developed warfarin skin necrosis despite appropriate anticoagulation with enoxaparin, and review the chemical and clinical difference between UFH and LMWH.

Absence of graft-versus-host disease in the isolated vascularized bone marrow transplant.

An isolated vascularized bone marrow transplant (iVBMT) model was developed to study the contribution of the bone marrow component in a composite tissue allograft. We hypothesized that the iVBMT would be functional and cause graft-versus-host disease (GVHD) in a fraction of the recipients. Lewis iVBMT grafts were transplanted to Lewis-Brown Norway recipients. Animals were sacrificed at various times from 1 to 14 weeks. Polymerase chain reaction for microchimerism was performed on the host's marrow. No animals exhibited signs of GVHD at death. Histologic examination of the grafts showed a normal mix of hematopoietic and fatty elements and appeared to be functional. Tissues usually affected-tongue, ear, liver, and gut-also showed no evidence of disease. Polymerase chain reaction demonstrated microchimerism in both groups. These findings suggest that the vascularized bone marrow within a composite tissue allograft is not the component that causes GVHD; rather, it may serve an immunomodulatory function for tolerance induction.

Composite tissue allotransplantation.

Composite tissue allotransplantation (CTA) recently took its first steps in the clinical arena in 1998 with the successful hand transplant performed in Lyons, France. That single operation represented a culmination of many years of laboratory research in multiple fields involving integumentary/musculoskeletal transplantation. Here we review the prerequisite developments in the field of immunology, microsurgery, and pharmacotherapy that helped bring CTA to clinical reality. This new field still has many unanswered questions which are addressed below. Additionally, new evolving research in CTA is also discussed.

An extraperitoneal isolated vascularized bone marrow transplant model in the rat.

An isolated vascularized bone marrow transplant (iVBMT) model was previously developed in the rat to specifically study the role of bone marrow and its environment in a composite tissue allotransplant. An extraperitoneal model was successfully created to avoid laparotomy and cross-clamping of the great vessels. The extraperitoneal iVBMT model consisted of a left donor femur that was harvested with its nutrient vessels, anastomosed to the right femoral vessels in a syngeneic host, and then placed subcutaneously in the abdominal wall. At explant, the graft vessels were grossly patent, and histology of the graft bones showed a viable marrow compartment. Polymerase chain reaction demonstrated peripheral chimerism in the recipients. This model is technically simple with minimal morbidity in the recipient animals. By using the iVBMT, future studies across semiallogeneic and allogeneic barriers will help define the role of the bone marrow compartment in composite tissue allotransplants to potentially induce immune tolerance.