Quality of Regional Nodal Irradiation Plans in Breast Cancer Patients Across a Large Network—Can We Translate Results From Randomized Trials Into the Clinic?

PurposeRegional nodal irradiation (RNI) improved disease-free survival by 3% to 5% in 2 large randomized trials, but this small absolute advantage relies on accurate contouring and dose delivery. We audited our network to determine compliance on regional nodal coverage, contouring, and dosimetric parameters with respect to accepted guidelines.Methods and MaterialsIn our network, we have established a clinical pathway for patients with node-positive breast cancer that guides indications for RNI and dosimetric goals. We reviewed records of 183 patients with nodal macrometastases after upfront surgery or involved nodes of any size after neoadjuvant chemotherapy. Radiation treatment plans were examined to determine lymph node volumes treated, whether nodes were contoured, quality of nodal contours, and whether target coverage and normal organ dosimetric constraints were met when RNI was delivered.ResultsDespite the presence of macrometastases on sentinel lymph node biopsy, no lymph nodes were treated in 2.2% (4 of 183). Of 179 patients who received nodal irradiation, 18 received radiation to axillary levels 1 and 2 only, and 161 patients received RNI. Overall, regional nodes were not treated despite strong indications in 7.6% (14 of 183). Treated nodes were not contoured for 2.2% (4 of 179), and lymph node contours were unacceptable in 15.4% (27 of 175). Of patients receiving RNI, 14.9% (24 of 161) did not have adequate nodal target volume coverage, mean heart dose was >4 Gy for 3.1% (5 of 161), and lung V20 Gy was >35% for 8.7% (14 of 161).ConclusionsAdherence to indications for regional nodal treatment was high, but nodes were either not contoured or had unacceptable contour quality in 18% of plans, and coverage was inadequate in 15%. Because the small disease-free survival advantage seen in trials may be decreased with these deviations, routine clinical practice requires detailed peer review to fully translate results of clinical trials.     

Human facial allotransplantation: patient selection and pertinent considerations

Devastating facial deformities can cause significant functional and psychosocial injury. Significant facial disfigurement can preclude meaningful human interaction. Allotransplantation of facial tissues for reconstruction of devastating deformities has become a clinical reality, with 15 transplants performed at various centers around the world. Restoration of aesthetics and functionality has been superior to that achieved by conventional reconstruction, without the morbidity of multiple surgeries. Unlike solid organ transplantation which can be life saving, facial transplantation is considered by many to be life enhancing, highlighting the ethical argument against justification of these procedures given the risks of lifelong immunosuppression. Meticulous patient selection is mandatory, and a multidisciplinary team approach is key for the program's success. The overriding goal of screening for candidacy is to identify and select subjects who have the best chance for a positive immunologic, functional, and quality-of-life outcome. This article reviews the pertinent considerations and screening approach for appropriate patient selection in facial tissue transplantation.     

Targeted mesenchymal stem cell and vascular endothelial growth factor strategies for repair of nerve defects with nerve tissue implanted autogenous vein graft conduits

Peripheral nerve gaps exceeding 1 cm require a bridging repair strategy. Clinical feasibility of autogenous nerve grafting is limited by donor site comorbidity. In this study we investigated neuroregenerative efficacy of autogenous vein grafts implanted with tissue fragments from distal nerve in combination with vascular endothelial growth factor (VEGF) or mesenchymal stem cells (MSCs) in repair of rat peripheral nerve defects. Six‐groups of Sprague‐Dawley rats (n = 8 each) were evaluated in the autogenous setting using a 1.6 cm long peroneal nerve defect: Empty vein graft (group 1), Nerve graft (group 2), Vein graft and nerve fragments (group 3), Vein graft and nerve fragments and blank microspheres (group 4), Vein graft and nerve fragments and VEGF microspheres (group 5), Vein graft and nerve fragments and MSCs (group 6). Nerve fragments were derived from distal segment. Walking track analysis, electrophysiology and nerve histomorphometry were performed for assessment. Peroneal function indices (PFI), electrophysiology (amplitude) and axon count results for group 2 were ?9.12 ± 3.07, 12.81 ± 2.46 mV, and 1697.88 ± 166.18, whereas the results for group 5 were ?9.35 ± 2.55, 12.68 ± 1.78, and 1566 ± 131.44, respectively. The assessment results did not reveal statistical difference between groups 2 and 5 (P > 0.05). The best outcomes were seen in group 2 and 5 followed by group 6. Compared to other groups, poorest outcomes were seen in group 1 (P ≤ 0.05). PFI, electrophysiology (amplitude) and axon count results for group 1 were ?208.82 ± 110.69, 0.86 ± 0.52, and 444.50 ± 274.03, respectively. Vein conduits implanted with distal nerve‐derived nerve fragments improved axonal regeneration. VEGF was superior to MSCs in facilitating nerve regeneration. © 2015 Wiley Periodicals, Inc. Microsurgery 36:578–585, 2016.     

Analysis of cellular response to isocyanate using N‐succinimidyl N‐methylcarbamate exposure in cultured mammalian cells

Isocyanates (R? N?C?O), one of the highly reactive industrial intermediates, possess the capability to modulate the bio‐molecules by forming toxic metabolites and adducts which may cause adverse health effects. Some of their toxic degradations have previously been unknown and overlooked; of which, molecular repercussions underlying their genetic hazards upon occupational/accidental exposures still remain as an intricate issue and are hitherto unknown. To assess the genotoxic potential of methyl isocyanate in cultured mammalian cells after in vitro exposure, we performed a study in three different normal cell lines MM55.K (mouse kidney epithelial), B/CMBA.Ov (mouse ovarian epithelial), and NIH/3T3 (primary mouse embryonic fibroblast). Cellular DNA damage response was studied for qualitative phosphorylation states of ATM, γH2AX proteins and quantitative state of p53 phosphorylation; DNA cell cycle analysis and measure of cellular apoptotic index before and after treatment were also investigated. Our results demonstrate that methyl isocyanate by negatively regulating the DNA damage response pathway, might promote cell cycle arrest, and apoptosis in cultured mammalian cells suggestive of causing genetic alterations. We anticipate that these data along with other studies reported in the literature would help to design better approaches in risk assessment of occupational and accidental exposure to isocyanates. We also predict that increasing knowledge on DNA damage‐triggered signaling leading to cell death could provide new strategies for investigating the effects of DNA repair disorders and decreased repair capacity on the toxicity and carcinogenic properties of environmental toxins. Environ. Mol. Mutagen., 2009. © 2009 Wiley‐Liss, Inc.     

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. [ACIWistar 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.Abbreviations BM Bone marrow - CPM Counts per minute - CTA Composite tissue allograft - FACS Fluorescence activated cell sorter - FITC Fluorescent iso-thiocyanate - GVH Graft-versus-host - GVHD Graft-versus-host disease - HVG Host-versus-graft - LN Lymph node - MAC Mixed allogeneic chimerism - MHC Major histocompatibility complex - MLR Mixed lymphocyte reaction - MoAb Monoclonal antibody - PBL Peripheral blood lymphocytes - SEM Standard error of mean - TBI Total body irradiation - TCD T-cell depletion/T-cell depleted - TCR T-cell receptor     

Heparin-induced thrombocytopenia: an autoimmune disorder regulated through dynamic autoantigen assembly/disassembly

Heparin‐induced thrombocytopenia (HIT) is the most common drug‐induced, antibody‐mediated cause of thrombocytopenia and thrombosis. HIT is caused by IgG antibodies that bind to epitopes on platelet factor 4 (PF4) released from activated platelets that develop when it forms complexes with heparin. Anti‐PF4/antibodies develop in over 50% of patients undergoing surgery involving cardiopulmonary bypass (CPB), an incidence 20‐fold higher than HIT. Why might this occur? Binding of HIT IgG occurs only over a narrow molar ratio of reactants, being optimal at 1 mol PF4 tetramer to 1 mol unfractionated heparin (UFH). At these ratios, PF4 and UFH form ultralarge (>670 kD) complexes that bind multiple IgG molecules/complex, are highly antigenic, and promote platelet activation. Low molecular weight heparin (LMWH), which is less antigenic, forms ultralarge complexes less efficiently and largely at supratherapeutic concentrations. In transgenic mice that vary in expression of human PF4 on their platelets, antigenic complexes form between PF4 and endogenous chondroitin sulfate. Binding of HIT IgG to platelets and induction of thrombocytopenia in vivo is proportional to PF4 expression. Heparin prolongs the duration and exacerbates the severity of the thrombocytopenia. High doses of heparin, as used in CPB, or protamine, which competes with PF4 for heparin, disrupts antigen formation and prevents thrombocytopenia induced by HIT antibody. These studies may help explain the disparity between the incidence of antibody formation and clinical disease and may help identify patients at risk for HIT (high platelet PF4). They also demonstrate that this autoimmune disease can be modulated at the level of autoantigen formation and point to rational means to intervene proximal to thrombin generation. J. Clin. Apheresis. 22:, 2007 © 2007 Wiley‐Liss, Inc.     

Effect of combined anticoagulation using heparin and bivalirudin on the hemostatic and inflammatory responses to cardiopulmonary bypass in the rat

BACKGROUND: Despite high-dose heparin anticoagulation, cardiopulmonary bypass (CPB) is still associated with marked hemostatic activation. The purpose of this study was to determine whether a reduced dose of bivalirudin, added as an adjunct to heparin, would reduce thrombin generation and circulating markers of inflammatory system activation during CPB as effectively as full-dose bivalirudin, without adversely affecting postoperative hemostasis. METHODS: Using a model of normothermic CPB in rats, the authors prospectively compared markers of thrombin generation (thrombin-antithrombin complexes) and inflammatory markers (tumor necrosis factor alpha, interleukin 1beta, interleukin 6, and interleukin 10) in three groups: conventional high-dose heparin (H), full-dose bivalirudin (B), and a combined group (standard high-dose heparin with the addition of reduced dose bivalirudin or H&B), at baseline, after 60 min of CPB, and 60 min after CPB. Postoperative hemostasis was also assessed. RESULTS: Groups H&B and B showed reduced thrombin-antithrombin complex formation during CPB compared with group H (P = 0.0003), and this persisted after CPB for group B (P = 0.009). Perioperative increases in interleukin 6 and interleukin 10 showed a trend toward being reduced in animals receiving bivalirudin (P = 0.06). Evidence of residual anticoagulation was found in group H&B as measured by activated clotting time (P = 0.04) and activated partial thromboplastin time (P = 0.02), but no intergroup difference in primary hemostasis was found. CONCLUSIONS: Bivalirudin attenuates hemostatic activation during experimental CPB with potential effects on markers of the inflammatory response. However, with this dosing regimen, the combination of heparin and bivalirudin does not seem to confer any measurable advantages over full-dose bivalirudin anticoagulation.