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Sample records for pretransplant graft irradiation

  1. Effect of total lymphoid irradiation and pretransplant blood transfusion on pancreatic islet allograft survival

    SciTech Connect

    Mendez-Picon, G.; McGeorge, M.

    1983-05-01

    Total lymphoid irradiation (TLI) has been shown to have a strong immunosuppressive effect both experimentally and clinically. Pretransplant blood transfusions have also been shown to have a strong beneficial effect in the outcome of organ transplantation. A study was made of the effect of TLI and pretransplant blood transfusions, alone and in combination, as an immunosuppressive modality in the isolated pancreatic islet transplant in the rat model. Donor rats (Fischer RT1v1) were kept on a 50% DL-ethionine supplemented diet for 4-6 weeks prior to pancreas removal. Recipient rats (Lewis RT1) were made diabetics prior to transplantation by iv injection of streptozotocin (45 mg/kg). Transfusion protocol consisted of a biweekly transfusion of 2 ml of either donor specific or third party transfusions. Total lymphoid irradiation was carried out by daily administration of 200 rads during one week prior to transplantation. Transplantation of the isolated islets was performed by intraportal injection. Syngeneic transplant of one and a half donor pancreata in each recipient reverted the diabetic condition indefinitely (greater than 100 days). Untreated allogenic grafts had a mean survival time (MST) of 5.2 days. Total lymphoid irradiation in dosages of 800, 1000, and 1200 rads, as the only immunosuppressive regimen, prolonged the MST of allografts to 15.3, 16.5, and 21.8 days, respectively (P less than .05). Pretransplant third party blood transfusion had no effect on allograft survival (MST 6.0). When donor specific blood transfusions were given, the MST was prolonged to 25.3 days (P less than .05). When TLI was administered to recipients of donor specific transfusions, the MST of the allografts did not show any statistical significant difference when compared with untreated animals. This abrogation of the beneficial effect of specific blood transfusion was observed in all dosages of TLI employed: 800 rad (MST 3.0), 1000 rad (MST 8.0), 1200 rad (MST 5.18).

  2. Graft irradiation abrogates graft-versus-host disease in combined pancreas-spleen transplantation

    SciTech Connect

    Schulak, J.A.; Sharp, W.J.

    1986-04-01

    A model of combined pancreas-spleen transplantation (PST) was studied in LBN F1 recipients of Lewis grafts in order to evaluate the efficacy of pretransplant graft irradiation in preventing lethal graft-versus-host disease (GVHD). Recipients of unmodified PST uniformly developed severe GVHD and died (MST = 16.7 +/- 3.8 days). Whole body donor irradiation with either 500 or 250 rad prevented lethal GVHD. Similarly, ex vivo graft irradiation with either 1000 or 500 rad also resulted in normal weight gain, graft function, and host survival for the 6-week study period. Conversely, delay of graft irradiation until 3 days after transplantation failed to prevent this complication (MST = 15.8 +/- 3.7 days). Recipients of irradiated grafts displayed glucose tolerance tests that were identical to those in the control group indicating that the doses of radiation employed in these experiments were not deleterious to islet function. Irradiated spleen grafts appeared histologically normal at 6 weeks after transplantation. Cells derived from these grafts failed to stimulate lymph node enlargement in a popliteal lymph node assay for GVHD, suggesting that these spleens may have become repopulated with host cells. These experiments confirm that PST has the potential to cause lethal GVHD and suggest that pretransplant graft irradiation may be used to prevent its occurrence.

  3. Spontaneous bacterial peritonitis prevalence in pre-transplant patients and its effect on survival and graft loss post-transplant

    PubMed Central

    Shah, Neeral L; Intagliata, Nicolas M; Henry, Zachary H; Argo, Curtis K; Northup, Patrick G

    2016-01-01

    AIM To investigate the incidence of spontaneous bacterial peritonitis (SBP) in pre-transplant patients and its effect on post transplant mortality and graft failure. METHODS We conducted a retrospective cohort study of patient records from the organ procurement and transplant network data set. Patients were identified by the presence of SBP pre-transplant. Univariate post-transplant survival models were constructed using the Kaplan-Meier technique and multivariate models were constructed using the Cox proportional hazards model. Variables that affected post-transplant graft survival were identified in the SBP population. RESULTS Forty-seven thousand eight hundred and eighty patient records were included in the analysis for both groups, and 1966 (4.11%) patients were identified in the data set as having pre-transplant SBP. Patients that had pre-transplant SBP had higher rates of graft loss from recurrent hepatitis C virus (HCV) (3.6% vs 2.0%, P < 0.0001), infections leading to graft loss (1.9% vs 1.3%, P = 0.02), primary non-function (4.3% vs 3.0%, P < 0.0001) and chronic rejection (1.1% vs 0.7%, P = 0.04). Kaplan-Meier survival analysis showed a statistically significant difference in all-cause survival in patients with a history of SBP vs those without (P < 0.0001). Pre-transplant history of SBP was independently predictive of mortality due to recurrent HCV (HR = 1.11, 95%CI: 1.02-1.21, P < 0.017) after liver transplantation. CONCLUSION HCV patients prior to the advent of directing acting anti-viral agents had a higher incidence of pre-transplant SBP than other patients on the liver transplant wait list. SBP history pre-transplant resulted in a higher rate of graft loss due to recurrent HCV infection and chronic rejection. PMID:28083084

  4. Pretransplant transcriptome profiles identify among kidneys with delayed graft function those with poorer quality and outcome.

    PubMed

    Mas, Valeria R; Scian, Mariano J; Archer, Kellie J; Suh, Jihee L; David, Krystle G; Ren, Qing; Gehr, Todd W B; King, Anne L; Posner, Marc P; Mueller, Thomas F; Maluf, Daniel G

    2011-01-01

    Robust biomarkers are needed to identify donor kidneys with poor quality associated with inferior early and longer-term outcome. The occurrence of delayed graft function (DGF) is most often used as a clinical outcome marker to capture poor kidney quality. Gene expression profiles of 92 preimplantation biopsies were evaluated in relation to DGF and estimated glomerular filtration rate (eGFR) to identify preoperative gene transcript changes associated with short-term function. Patients were stratified into those who required dialysis during the first week (DGF group) versus those without (noDGF group) and subclassified according to 1-month eGFR of >45 mL/min (eGFR(hi)) versus eGFR of ≤45 mL/min (eGFR(lo)). The groups and subgroups were compared in relation to clinical donor and recipient variables and transcriptome-associated biological pathways. A validation set was used to confirm target genes. Donor and recipient characteristics were similar between the DGF versus noDGF groups. A total of 206 probe sets were significant between groups (P < 0.01), but the gene functional analyses failed to identify any significantly affected pathways. However, the subclassification of the DGF and noDGF groups identified 283 probe sets to be significant among groups and associated with biological pathways. Kidneys that developed postoperative DGF and sustained an impaired 1-month function (DGF(lo) group) showed a transcriptome profile of significant immune activation already preimplant. In addition, these kidneys maintained a poorer transplant function throughout the first-year posttransplant. In conclusion, DGF is a poor marker for organ quality and transplant outcome. In contrast, preimplant gene expression profiles identify "poor quality" grafts and may eventually improve organ allocation.

  5. Pre-transplant donor CD4(-) invariant NKT cell expansion capacity predicts the occurrence of acute graft-versus-host disease.

    PubMed

    Rubio, M-T; Bouillié, M; Bouazza, N; Coman, T; Trebeden-Nègre, H; Gomez, A; Suarez, F; Sibon, D; Brignier, A; Paubelle, E; Nguyen-Khoc, S; Cavazzana, M; Lantz, O; Mohty, M; Urien, S; Hermine, O

    2017-04-01

    Clinically useful pre-transplant predictive factors of acute graft-versus-host-disease (aGVHD) after allogeneic hematopoietic stem cell transplantation (allo-SCT) are lacking. We prospectively analyzed HSC graft content in CD34(+), NK, conventional T, regulatory T and invariant natural killer T (iNKT) cells in 117 adult patients before allo-SCT. Results were correlated with occurrence of aGVHD and relapse. In univariate analysis, iNKT cells were the only graft cell populations associated with occurrence of aGVHD. In multivariate analysis, CD4(-) iNKT/T cell frequency could predict grade II-IV aGVHD in bone marrow and peripheral blood stem cell (PBSC) grafts, while CD4(-) iNKT expansion capacity was predictive in PBSC grafts. Receiver operating characteristic analyses determined the CD4(-) iNKT expansion factor as the best predictive factor of aGVHD. Incidence of grade II-IV aGVHD was reduced in patients receiving a graft with an expansion factor above versus below 6.83 (9.7 vs 80%, P<0.0001), while relapse incidence at two years was similar (P=0.5).The test reached 94% sensitivity and 100% specificity in the subgroup of patients transplanted with human leukocyte antigen 10/10 PBSCs without active disease. Analysis of this CD4(-) iNKT expansion capacity test may represent the first diagnostic tool allowing selection of the best donor to avoid severe aGVHD with preserved graft-versus-leukemia effect after peripheral blood allo-SCT.

  6. Postoperative irradiation of fresh autogenic cancellous bone grafts

    SciTech Connect

    Schwartz, H.C.; Leake, D.L.; Kagan, A.R.; Snow, H.; Pizzoferrato, A.

    1986-01-01

    Discontinuity defects were created in the mandibles of dogs and then reconstructed immediately with fresh autogenic cancellous bone grafts and Dacron-urethane prostheses. The grafts were irradiated to a total dose of 5000 rads after waiting intervals of between 3 and 12 weeks. Nonirradiated grafts served as controls. The grafts were evaluated clinically, radiographically, and histologically. There was complete incorporation of all grafts, regardless of the interval between surgery and radiotherapy. There were no soft-tissue complications. The controls were distinguishable from the irradiated grafts only by the presence of hematopoietic bone marrow. Fibrofatty marrow was observed in the irradiated grafts. Theoretical support for this technique is found in the biology of cancellous bone grafting and the pathology of radiation injury. In view of the difficulties associated with mandibular bone grafting in preoperatively irradiated patients, a new method of reconstructing selected cancer patients who require both mandibular resection and radiotherapy is suggested.

  7. Influence of Deceased Donor and Pretransplant Recipient Parameters on Early Overall Kidney Graft-Survival in Germany

    PubMed Central

    Fischer-Fröhlich, Carl-Ludwig; Kutschmann, Marcus; Feindt, Johanna; Schmidtmann, Irene; Kirste, Günter; Frühauf, Nils R.; Wirges, Ulrike; Rahmel, Axel; Schleicher, Christina

    2015-01-01

    Background. Scarcity of grafts for kidney transplantation (KTX) caused an increased consideration of deceased donors with substantial risk factors. There is no agreement on which ones are detrimental for overall graft-survival. Therefore, we investigated in a nationwide multicentre study the impact of donor and recipient related risks known before KTX on graft-survival based on the original data used for allocation and graft acceptance. Methods. A nationwide deidentified multicenter study-database was created of data concerning kidneys donated and transplanted in Germany between 2006 and 2008 as provided by the national organ procurement organization (Deutsche Stiftung Organtransplantation) and BQS Institute. Multiple Cox regression (significance level 5%, hazard ratio [95% CI]) was conducted (n = 4411, isolated KTX). Results. Risk factors associated with graft-survival were donor age (1.020 [1.013–1.027] per year), donor size (0.985 [0.977–0.993] per cm), donor's creatinine at admission (1.002 [1.001–1.004] per µmol/L), donor treatment with catecholamine (0.757 [0.635–0.901]), and reduced graft-quality at procurement (1.549 [1.217–1.973]), as well as recipient age (1.012 [1.003–1.021] per year), actual panel reactive antibodies (1.007 [1.002–1.011] per percent), retransplantation (1.850 [1.484–2.306]), recipient's cardiovascular comorbidity (1.436 [1.212–1.701]), and use of IL2-receptor antibodies for induction (0.741 [0.619–0.887]). Conclusion. Some donor characteristics persist to impact graft-survival (e.g., age) while the effect of others could be mitigated by elaborate donor-recipient match and care. PMID:26539298

  8. Pretransplant β2-Microglobulin Is Associated with the Risk of Acute Graft-versus-Host-Disease after Allogeneic Hematopoietic Cell Transplant.

    PubMed

    Costa-Lima, Carolina; Miranda, Eliana Cristina Martins; Colella, Marcos Paulo; Aranha, Francisco Jose Penteado; de Souza, Carmino Antonio; Vigorito, Afonso Celso; De Paula, Erich Vinicius

    2016-07-01

    The risk of acute graft-versus-host disease (aGVHD) can be reliably estimated by the hematopoietic cell transplantation-specific comorbidity index (HCT-CI), which can be further refined by the incorporation of pre-hematopoietic cell transplantation (HCT) serum levels of inflammatory biomarkers such as ferritin and albumin. β2-Microglobulin (β2-m) is a key component of the MHC class I complex, which is independently associated with mortality and frailty in the general population. We took advantage of our institutional protocol that includes measurement of pre-HCT β2-m serum levels in the most patients to investigate whether pre-transplant β2-m levels were associated with the risk of aGVHD. One hundred three consecutive patients submitted to allogeneic HCT, of which 26 developed grades II to IV aGVHD, were included in the analysis. β2-m was significantly associated with age and HCT-CI. Higher levels of β2-m were observed in patients who developed aGVHD (P = .008). In the multivariate Cox regression model, β2-m and HCT-CI remained independently associated with the risk of developing aGVHD. In conclusion, the association between β2-m and the occurrence of aGVHD suggests that the measurement of this protein before HCT might represent an additional element for risk stratification of aGVHD.

  9. The Kidney Donor Profile Index (KDPI) of Marginal Donors Allocated by Standardized Pre-Transplant Donor Biopsy Assessment: Distribution and Association with Graft Outcomes

    PubMed Central

    Gandolfini, I.; Buzio, C.; Zanelli, P.; Palmisano, A.; Cremaschi, E.; Vaglio, A.; Piotti, G.; Melfa, L.; La Manna, G.; Feliciangeli, G.; Cappuccilli, M.; Scolari, M.P.; Capelli, I.; Panicali, L.; Baraldi, O.; Stefoni, S.; Buscaroli, A.; Ridolfi, L.; D'Errico, A.; Cappelli, G.; Bonucchi, D.; Rubbiani, E.; Albertazzi, A.; Mehrotra, A.; Cravedi, P.; Maggiore, U.

    2015-01-01

    Pre-transplant donor biopsy (PTDB)-based marginal-donor allocation systems to single or dual renal transplantation could increase the use of organs with Kidney Donor Profile Index (KDPI) in the highest range (e.g. >80 or >90), whose discard rate approximates 50% in the US. To test this hypothesis, we retrospectively calculated the KDPI and analyzed the outcomes of 442 marginal kidney transplants (340 single transplants: 278 with a PTDB Remuzzi score <4 [median KDPI:87; interquartile range(IQR):78-94] and 62 with a score =4 [median KDPI:87; IQR:76-93]; 102 dual transplants [median KDPI: 93; IQR:86-96]) and 248 single standard transplant controls [median KDPI:36; IQR:18-51]. PTDB-based allocation of marginal grafts led to a limited discard rate of 15% for kidneys with KDPI of 80-90 and of 37% for kidneys with a KDPI of 91-100. Although 1-year eGFRs were significantly lower in recipients of marginal kidneys (-9.3, -17.9, and -18.8ml/min, for dual transplants, single kidneys with PTDB score <4, and =4, respectively; P<0.001), graft survival (median follow-up 3.3 years) was similar between marginal and standard kidney transplants (hazard ratio: 1.20 [95% confidence interval: 0.80 to 1.79; P=0.38]). In conclusion, PTDB-based allocation allows the safe transplantation of kidneys with KDPI in the highest range that may otherwise be discarded. PMID:25155294

  10. Pre-transplant Evaluation of Donor Urinary Biomarkers can Predict Reduced Graft Function After Deceased Donor Kidney Transplantation

    PubMed Central

    Koo, Tai Yeon; Jeong, Jong Cheol; Lee, Yonggu; Ko, Kwang-Pil; Lee, Kyoung-Bun; Lee, Sik; Park, Suk Joo; Park, Jae Berm; Han, Miyeon; Lim, Hye Jin; Ahn, Curie; Yang, Jaeseok

    2016-01-01

    Abstract Several recipient biomarkers are reported to predict graft dysfunction, but these are not useful in decision making for the acceptance or allocation of deceased donor kidneys; thus, it is necessary to develop donor biomarkers predictive of graft dysfunction. To address this issue, we prospectively enrolled 94 deceased donors and their 109 recipients who underwent transplantation between 2010 and 2013 at 4 Korean transplantation centers. We investigated the predictive values of donor urinary neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), and L-type fatty acid binding protein (L-FABP) for reduced graft function (RGF). We also developed a prediction model of RGF using these donor biomarkers. RGF was defined as delayed or slow graft function. Multiple logistic regression analysis was used to generate a prediction model, which was internally validated using a bootstrapping method. Multiple linear regression analysis was used to assess the association of biomarkers with 1-year graft function. Notably, donor urinary NGAL levels were associated with donor AKI (P = 0.014), and donor urinary NGAL and L-FABP were predictive for RGF, with area under the receiver-operating characteristic curves (AUROC) of 0.758 and 0.704 for NGAL and L-FABP, respectively. The best-fit model including donor urinary NGAL, L-FABP, and serum creatinine conveyed a better predictive value for RGF than donor serum creatinine alone (P = 0.02). In addition, we generated a scoring method to predict RGF based on donor urinary NGAL, L-FABP, and serum creatinine levels. Diagnostic performance of the RGF prediction score (AUROC 0.808) was significantly better than that of the DGF calculator (AUROC 0.627) and the kidney donor profile index (AUROC 0.606). Donor urinary L-FABP levels were also predictive of 1-year graft function (P = 0.005). Collectively, these findings suggest donor urinary NGAL and L-FABP to be useful biomarkers for RGF, and support

  11. Cartilage grafting in facial reconstruction with special consideration of irradiated grafts

    SciTech Connect

    Donald, P.J.

    1986-07-01

    The search for the perfect facial implant for reconstruction of the face continues. Cartilage, once thought to be an undesirable graft material because of its propensity for absorption, has regained popularity in the past decade. Various preparation techniques have been employed to ensure graft sterility and diminished absorption. An improved understanding of cartilage structure and physiology has shed considerable light on the host-graft relationship. Gamma irradiation is a time-honored method of preservation. An experiment was undertaken to investigate the physiology of irradiated cartilage grafts following prolonged implantation on the facial skeleton of sheep and dog. Merthiolate preserved grafts were used as controls. Direct observation, histochemical techniques, autoradiography, and transmission electron micrography were used to determine chondrocyte viability and matrix composition. It was surprising to note that following implantation of 16 to 72 months, complete resorption was seen in 87.7% of the irradiated grafts and in 43.8% of the Merthiolate stored controls. Many of the grafts acquired chondrocytes from the host and produced new proteoglycan matrix as well as undergoing some degree of ossification. A comparison to the clinical situation in humans is made. 98 references.

  12. Albumin grafting on biomaterial surfaces using gamma-irradiation

    SciTech Connect

    Kamath, K.R.

    1993-01-01

    Surface modification has been used extensively in various fields to introduce desirable surface properties without affecting the bulk properties of the material. In the area of biomaterials, the approach of surface modification offers an effective alternative to the synthesis of new biomaterials. The specific objective of this study was to modify different biomaterial surfaces by albumin grafting to improve their blood compatibility. The modified surfaces were characterized for surface-induced platelet activation and thrombus formation. This behavior was correlated with the conditions used for grafting. In particular, albumin was functionalized to introduce pendant double bonds into the molecule. The functionalized albumin was covalently attached to various surfaces, such as dimethyldichlorosilane-coated glass, polypropylene, polycarbonate, poly(vinyl chloride), and polyethylene by gamma-irradiation. Platelet adhesion and activation on these surfaces was examined using video microscopy and scanning electron microscopy. The extent of grafting was found to be dependent on the albumin concentration used for adsorption and the gamma-irradiation time. Release of the grafted albumin during exposure to blood was minimal. The albumin-grafted fibers maintained their thromboresistant properties even after storage at elevated temperatures for prolonged time periods. Finally, the approach was used to graft albumin on the PLEXUS Adult Hollow Fiber Oxygenators (Shiley). The blood compatibility of the grafted oxygenators improved significantly when compared to controls.

  13. Effects of pre- and postoperative irradiation on the healing of bone grafts in the rabbit

    SciTech Connect

    Morales, M.J.; Marx, R.E.; Gottlieb, C.F.

    1987-01-01

    Healing of cellular bone grafts irradiated at various times in the postsurgical course was compared to the healing characteristics of bone grafts placed into already irradiated tissue and to controls of irradiated host mandible in a rabbit model. Physical graft consolidation was assessed by load stress characteristics and serial histologic examination. Results indicated that grafts placed into already irradiated tissues failed to form bone in both phases of expected regeneration resulting in structurally weakened and histologically deficient ossicles. Bone grafts irradiated after placement were tolerant of irradiation. Bone grafts irradiated after four weeks were found to be less affected by irradiation than those irradiated within the first four weeks, forming an ossicle structurally and histologically superior to that of bone ossicles developed from grafts placed into irradiated tissues.

  14. Pretransplant pulmonary function tests predict risk of mortality following fractionated total body irradiation and allogeneic peripheral blood stem cell transplant

    SciTech Connect

    Singh, Anurag K. . E-mail: singan@mail.nih.gov; Karimpour, Shervin E.; Savani, Bipin N.; Guion, Peter M.S.; Hope, Andrew J.; Mansueti, John R.; Ning, Holly; Altemus, Rosemary M. Ph.D.; Wu, Colin O.; Barrett, A. John

    2006-10-01

    Purpose: To determine the value of pulmonary function tests (PFTs) done before peripheral blood stem cell transplant (PBSCT) in predicting mortality after total body irradiation (TBI) performed with or without dose reduction to the lung. Methods and Materials: From 1997 to 2004, 146 consecutive patients with hematologic malignancies received fractionated TBI before PBSCT. With regimen A (n = 85), patients were treated without lung dose reduction to 13.6 gray (Gy). In regimen B (n = 35), total body dose was decreased to 12 Gy (1.5 Gy twice per day for 4 days) and lung dose was limited to 9 Gy by use of lung shielding. In regimen C (n = 26), lung dose was reduced to 6 Gy. All patients received PFTs before treatment, 90 days after treatment, and annually. Results: Median follow-up was 44 months (range, 12-90 months). Sixty-one patients had combined ventilation/diffusion capacity deficits defined as both a forced expiratory volume in the first second (FEV{sub 1}) and a diffusion capacity of carbon dioxide (DLCO) <100% predicted. In this group, there was a 20% improvement in one-year overall survival with lung dose reduction (70 vs. 50%, log-rank test p = 0.042). Conclusion: Among those with combined ventilation/diffusion capacity deficits, lung dose reduction during TBI significantly improved survival.

  15. Li + grafting of ion irradiated polyethylene

    NASA Astrophysics Data System (ADS)

    Švorčík, V.; Rybka, V.; Vacík, J.; Hnatowicz, V.; Öchsner, R.; Ryssel, H.

    1999-02-01

    Foils of oriented polyethylene (PE) were irradiated with 63 keV Ar + and 155 keV Xe + ions to different fluences at room temperature and then doped from water solution of LiCl. The as irradiated and irradiated plus doped samples were examined by IR, EPR and neutron depth profiling (NDP) technique. The sheet resistance was also measured by the standard two points method. After Li salt doping of ion modified layer of PE, a reaction between degraded macromolecules and Li occur and thus a new chemical structure C-Li + is formed. Owing to the presence of these cations on the polymer chain, the irradiated plus doped layer exhibits higher electric conductivity compared to as-irradiated ones.

  16. Irradiated homologous cartilage grafts. Long-term results

    SciTech Connect

    Welling, D.B.; Maves, M.D.; Schuller, D.E.; Bardach, J.

    1988-03-01

    The use of irradiated homologous cartilage for the restoration of facial contour defects remains a controversial issue in reconstructive surgery. Both favorable and unfavorable reports can be found in the literature. Some basic research concerning the rate and mechanism of resorption has been completed but has failed to resolve the issue of the usefulness of this material in day-to-day practice. One frequently cited reference concerning the use of irradiated homologous cartilage in reconstructive surgery was coauthored by two of the present investigators ten years ago. In an effort to place this study in a long-term perspective, we examined 42 of the original 107 patients who formed the initial population base. Sixty-two of the original 145 irradiated homologous cartilage grafts have been followed up for an average of nine years, with an average resorption rate of approximately 75%. Eighteen of 24 grafts followed up from 11 to 16 years completely resorbed. In spite of complete graft resorption, some patients have maintained satisfactory facial contour with fibrous tissue replacement of the cartilage.

  17. Cellulose functionalization via high-energy irradiation-initiated grafting of glycidyl methacrylate and cyclodextrin immobilization

    NASA Astrophysics Data System (ADS)

    Desmet, Gilles; Takács, Erzsébet; Wojnárovits, László; Borsa, Judit

    2011-12-01

    Cotton-cellulose was functionalized using gamma-irradiation-induced grafting of glycidyl methacrylate (GMA) to obtain a hydrophobic cellulose derivative with epoxy groups suitable for further chemical modification. Two grafting techniques were applied. In pre-irradiation grafting (PIG) cellulose was irradiated in air and then immersed in a GMA monomer solution, whereas in simultaneous grafting (SG) cellulose was irradiated in an inert atmosphere in the presence of the monomer. PIG led to a more homogeneous fiber surface, while SG resulted in higher grafting yield but showed clear indications of some GMA-homopolymerization. Effects of the reaction parameters (grafting method, absorbed dose, monomer concentration, solvent composition) were evaluated by SEM, gravimetry (grafting yield) and FTIR spectroscopy. Water uptake of the cellulose decreased while adsorption of a pesticide molecule increased upon grafting. The adsorption was further enhanced by β-cyclodextrin immobilization during SG. This method can be applied to produce adsorbents from cellulose based agricultural wastes.

  18. Pre-irradiation induced emulsion graft polymerization of acrylonitrile onto polyethylene nonwoven fabric

    NASA Astrophysics Data System (ADS)

    Liu, Hanzhou; Yu, Ming; Deng, Bo; Li, Linfan; Jiang, Haiqing; Li, Jingye

    2012-01-01

    Acrylonitrile has been widely used in the modification of polymers by graft polymerization. In the present work, pre-irradiation induced emulsion graft polymerization method is used to introduce acrylonitrile onto PE nonwoven fabric instead of the traditional reaction in organic solvents system. The degree of grafting (DG) is measured by gravimetric method and the kinetics of the graft polymerization is studied. The existence of the graft chains is proven by Fourier transform infrared spectroscopy (FT-IR) analysis. Thermal stability of the grafted polymer is measured by Thermogravimetric analysis (TGA).

  19. The effects of irradiation dose on the stiffness of cartilage grafts.

    PubMed

    Donald, P J; Deckard-Janatpour, K; Sharkey, N; Lagunas-Solar, M

    1996-03-01

    Various centers report irradiated cartilage graft absorption rates that differ quite widely. We postulated that a major factor governing this phenomenon might be irradiation dose. Irradiation produces collagen cross-binding and increased resistance to absorption of such material when implanted. Since cross-binding produces stiffening of collagen, cartilage grafts were exposed to increasing doses of irradiation and their elastic modulus was measured. The postulate was that increasing radiation doses will produce grafts of increasing stiffness. Sternal cartilage, harvested from horses, was cut into blocks of a standard size and irradiated to 4, 6, 8, and 10 megarads. The elastic modulus of each specimen and matched control were measured on an Instron flexural testing machine (Instron Corp, Canton, MA). Irradiation at all four doses reduced the elastic modulus of the cartilage grafts, with the lowest dose producing a reduction of 50% and the highest dose one of 90%. High-dose irradiation appears to lessen greatly the stiffness of cartilage grafts and may be responsible for increasing absorption of grafts in centers in which high doses are used.

  20. Synthesis and characterization of azo acrylates grafted onto polyethylene terephthalate by gamma irradiation

    NASA Astrophysics Data System (ADS)

    Bucio, Emilio; Skewes, Phill; Burillo, Guillermina

    2005-07-01

    Polyethylene terephthalate (PET) films were grafted with acryloyl chloride by gamma irradiation, and the grafted films were reacted with Disperse Red 1 or 4-phenylazophenol. The films where characterized by atomic force microscopy, differential scanning calorimetry, FTIR-ATR, light polarized microscopy, elemental analysis and UV spectroscopy. The surface of the films was homogeneous, and the dye underwent trans to cis photoreaction, whereby the red films became colorless by the irradiation of UV light at room temperature.

  1. Grafting of acrylic acid onto polypropylene films irradiated with argon ions

    NASA Astrophysics Data System (ADS)

    Massa, G.; Mazzei, R.; García Bermúdez, G.; Filevich, A.; Smolko, E.

    2005-07-01

    Polypropylene (PP) foils were irradiated with 100 keV energy Argon ions at different fluences ranging from 1012 up to 2 × 1015 cm-2 and then grafted with acrylic acid (AA). The grafting yield was measured by weight difference and the structural changes on the films were analysed using Fourier transform infrared spectroscopy (FTIR). Different parameters that determined the grafting process such us fluence, grafting time and monomer concentration were analysed. The grafting reached an optimum value at 79% in aqueous solution at 30 min grafting time. The grafting yield as a function of the ion fluence plot, presented a maximum value, as previously found in a study of heavy beam on polymers.

  2. Grafting of HEMA onto dopamine coated stainless steel by 60Co-γ irradiation method

    NASA Astrophysics Data System (ADS)

    Jin, Wanqin; Yang, Liming; Yang, Wei; Chen, Bin; Chen, Jie

    2014-12-01

    A novel method for grafting of 2-hydroxyethyl methacrylate (HEMA) onto the surface of stainless steel (SS) was explored by using 60Co-γ irradiation. The surface of SS was modified by coating of dopamine before radiation grafting. The grafting reaction was performed in a simultaneous irradiation condition. The chemical structures change of the surface before and after grafting was demonstrated by Fourier transform infrared (FTIR) spectrometer. The hydrophilicity of the samples was determined by water contact angle measurement in the comparison of the stainless steel in the conditions of pristine, dopamine coated and HEMA grafted. Surface morphology of the samples was characterized by atomic force microscope (AFM) and scanning electron microscope (SEM). The corrosion resistance properties of the samples were evaluated by Tafel polarization curve. The hemocompatibility of the samples were tested by platelet adhesion assay.

  3. Allograft tolerance in pigs after fractionated lymphoid irradiation. II. Kidney graft after conventional total lymphoid irradiation and bone marrow cell grafting

    SciTech Connect

    Fradelizi, D.; Mahouy, G.; de Riberolles, C.; Lecompte, Y.; Alhomme, P.; Douard, M.C.; Chotin, G.; Martelli, H.; Daburon, F.; Vaiman, M.

    1981-05-01

    Experiments with pigs have been performed in order to establish bone marrow chimerism and kidney graft tolerance between SLA genotyped semi-incompatible animals. Recipients were conditioned by means of conventional fractionated total lymphoid irradiation (TLI) delivered by a vertical cobalt source. The principal lymphoid regions of the pig, including thymus and spleen, were submitted to irradiation. Two protocols were tested: A = 250 cGy four times a week x 13 times (TLI) (two animals) and B = 350 cGy three times a week x 8 times (TLI) (four animals). Bone marrow cells were injected 24 h after the last irradiation. One day later, bilateral nephrectomy and the graft of one kidney from the bone marrow cell donor were performed simultaneously. Results convinced us that application of the TLI protocol to humans is not yet practicable and that further experimental work is needed.

  4. Increasing irradiation temperature maximizes vitamin E grafting and wear resistance of ultrahigh molecular weight polyethylene.

    PubMed

    Oral, Ebru; Neils, Andrew L; Rowell, Shannon L; Lozynsky, Andrew J; Muratoglu, Orhun K

    2013-04-01

    Vitamin E stabilization of radiation crosslinked ultrahigh molecular weight polyethylene (UHMWPE) for total joint implants can be done by blending of UHMWPE resin powder with vitamin E, followed by consolidation and irradiation of the blend. It is well known that vitamin E prevents crosslinking in UHMWPE during ionizing radiation. We hypothesized that there would also be a significant amount of grafting of vitamin E onto UHMWPE during irradiation. Spectroscopic analysis of radiation crosslinked vitamin E-blended UHMWPE before and after extraction with boiling hexane showed vitamin E grafting in up to 30% of the blended vitamin E. Grafting increased with irradiation temperature. We also discovered that increasing irradiation temperature resulted in better preservation of active vitamin E in the polymer and increased crosslinking efficiency of UHMWPE. As a result, warm-irradiated vitamin E-blended UHMWPEs had significantly less wear than those irradiated at ambient temperature. It may be desirable to graft vitamin E on UHMWPE to decrease the possibility of elution and increase long-term stability. Warm irradiation of vitamin E blends may present an advantage in increasing vitamin E potency, as well as decreasing the wear of UHMWPE, which is crucial in decreasing the incidence of periprosthetic osteolysis in total joint replacement patients.

  5. Graft irradiation in the treatment of acute rejection of renal transplants: a randomized study

    SciTech Connect

    Pilepich, M.V.; Anderson, C.B.; Etheredge, E.E.; Sicard, G.A.; Melzer, J.S.; Blum, J.

    1982-05-01

    A randomized study of graft irradiation in the treatment of acute rejection of renal transplants was conducted from 1978 to 1981. Patients developing clinical signs of an acute graft rejection received customary antirejection treatment in the form of intravenous administration of high-dose (1 gm per day) of methylprednisolone. They were at the same time randomized to either receive therapeutic irradiation (175 rad every other day to a total of 525 rad) or sham irradiation. Neither the patient nor the Transplant Service surgeons knew at any time whether the radiation treatment had been given. Eighty-three rejection episodes occurring in 64 grafts were entered into the study. Acute rejection was reversed in 84.5% of grafts in the control and 75% in the treated group. The incidence of recurrent rejection was higher in the treated group (66 vs. 46%) and graft survival was lower (22% vs. 54%). The study failed to demonstrate a beneficial effect of graft irradiation in the treatment of acute renal allograft rejection, when used in conjunction with high dose steriods.

  6. RECIPIENT PRETRANSPLANT INOSINE MONOPHOSPHATE DEHYDROGENASE ACTIVITY IN NONMYELOABLATIVE HCT

    PubMed Central

    Bemer, Meagan J.; Risler, Linda J.; Phillips, Brian R.; Wang, Joanne; Storer, Barry E.; Sandmaier, Brenda M.; Duan, Haichuan; Raccor, Brianne S.; Boeckh, Michael J.; McCune, Jeannine S.

    2014-01-01

    Mycophenolic acid, the active metabolite of mycophenolate mofetil (MMF), inhibits inosine monophosphate dehydrogenase (IMPDH) activity. IMPDH is the rate-limiting enzyme involved in de novo synthesis of guanosine nucleotides and catalyzes the oxidation of inosine 5’- monophosphate (IMP) to xanthosine 5’-monophosphate (XMP). We developed a highly sensitive liquid chromatography–mass spectrometry method to quantitate XMP concentrations in peripheral blood mononuclear cells (PMNC) isolated from the recipient pretransplant and used this method to determine IMPDH activity in 86 nonmyeloablative allogeneic hematopoietic cell transplantation (HCT) patients. The incubation procedure and analytical method yielded acceptable within-sample and within-individual variability. Considerable between-individual variability was observed (12.2-fold). Low recipient pretransplant IMPDH activity was associated with increased day +28 donor T-cell chimerism, more acute graft-versus-host disease (GVHD), lower neutrophil nadirs, and more cytomegalovirus reactivation, but not with chronic GVHD, relapse, non-relapse mortality, or overall mortality. We conclude that quantitation of the recipient’s pretransplant IMPDH activity in PMNC lysate could provide a useful biomarker to evaluate a recipient’s sensitivity to MMF, but confirmatory studies are needed. Further trials should be conducted to confirm our findings and to optimize postgrafting immunosuppression in nonmyeloablative HCT recipients. PMID:24923537

  7. Free bone graft reconstruction of irradiated facial tissue: Experimental effects of basic fibroblast growth factor stimulation

    SciTech Connect

    Eppley, B.L.; Connolly, D.T.; Winkelmann, T.; Sadove, A.M.; Heuvelman, D.; Feder, J. )

    1991-07-01

    A study was undertaken to evaluate the potential utility of basic fibroblast growth factor in the induction of angiogenesis and osseous healing in bone previously exposed to high doses of irradiation. Thirty New Zealand rabbits were evaluated by introducing basic fibroblast growth factor into irradiated mandibular resection sites either prior to or simultaneous with reconstruction by corticocancellous autografts harvested from the ilium. The fate of the free bone grafts was then evaluated at 90 days postoperatively by microangiographic, histologic, and fluorochrome bone-labeling techniques. Sequestration, necrosis, and failure to heal to recipient osseous margins was observed both clinically and histologically in all nontreated irradiated graft sites as well as those receiving simultaneous angiogenic stimulation at the time of graft placement. No fluorescent activity was seen in these graft groups. In the recipient sites pretreated with basic fibroblast growth factor prior to placement of the graft, healing and reestablishment of mandibular contour occurred in nearly 50 percent of the animals. Active bone formation was evident at cortical margins adjacent to the recipient sites but was absent in the more central cancellous regions of the grafts.

  8. Effects of extra irradiation on surface and bulk properties of PMPC-grafted cross-linked polyethylene.

    PubMed

    Yamane, Shihori; Kyomoto, Masayuki; Moro, Toru; Watanabe, Kenichi; Hashimoto, Masami; Takatori, Yoshio; Tanaka, Sakae; Ishihara, Kazuhiko

    2016-01-01

    Sterilization using high-energy irradiation is an important aspect of implementing an ultra-high molecular weight polyethylene acetabular liner in total hip arthroplasty (THA). In this study, we evaluate the effects of extra irradiations such as gamma-ray or plasma irradiation during sterilization of the poly(2-methacryloyloxyethyl phosphorylcholine [MPC]) (PMPC) surface and cross-linked polyethylene (CLPE) substrate of a PMPC-grafted CLPE acetabular liner. The PMPC-grafted surface yielded high wettability and low friction properties regardless of the extra irradiations as compared with untreated CLPE. During a hip simulator test, wear resistance of the PMPC-grafted CLPE liner was maintained after extra irradiation, which is due to the high wettability characteristics of the PMPC surface. In particular, the PMPC-grafted CLPE liner treated with plasma irradiation showed greater wettability and wear resistance than that with gamma-ray irradiation. However, we could not clearly observe the changes in chemical properties and morphology of the PMPC surface after both extra irradiations. The physical and mechanical properties attributed to CLPE substrate performance were also unchanged. In contrast, PMPC-grafted CLPE treated with plasma irradiation showed improved oxidation resistance as compared to that treated with gamma-ray irradiation after accelerated aging. Thus, we conclude that PMPC-grafted CLPE with plasma irradiation has promise as a lifelong solution for bearing in THA.

  9. Pretransplant and protocol biopsies may help in defining short and mid-term kidney transplant outcome.

    PubMed

    Esposito, C; Migotto, C; Torreggiani, M; Maggi, N; Manini, A; Castoldi, F; Grosjean, F; Mangione, F; Abelli, M; Scaramuzzi, M L; Catucci, D; Dal Canton, A

    2012-09-01

    Although many variables may affect long-term graft survival no biomarker is available to identify donor kidney with poor quality and with inadequate short and long-term outcome. While in marginal donors pre-transplant renal biopsies are commonly performed to establish if donor kidneys are suitable for transplantation they are not performed in standard donors. In this study we assessed the relevance of pre-transplant morphological features on post-transplant renal function and evaluated the association between perioperative parameters with posttransplant histological and clinical findings. Kidney transplant recipients undergone pre-transplant and post transplant protocol biopsies at 1, 6, and 12 months were enrolled in the study. Perioperative and posttransplant clinical and biochemical parameters were recorded. Semiquantitative analysis of PAS stained kidney sections was used to determine the degree of lesions. Glomerular volume was measured by computed morphometry. A strong inverse correlation was found between donor age and renal graft function at 1, 6, and 12 months after transplantation. A prompt functional recovery was associated with a better renal function at 6 months and one year. Kidneys with higher glomerular volume demonstrated a lower serum creatinine at 1 month. Higher tubulo-interstitial grading at protocol biopsies was associated with a poor renal function at 1 month. Our findings confirm the importance of donor age in kidney transplant long-term outcome and demonstrate that pretransplant and protocol biopsies are valid options to determine graft outcome and to define therapeutic strategies and tailor immunosuppressive regimen for each patient.

  10. Pre-Transplant Cardiovascular Risk Factors Affect Kidney Allograft Survival: A Multi-Center Study in Korea

    PubMed Central

    Lee, Jung Pyo; Bae, Eunjin; Kang, Eunjeong; Kim, Hack-Lyoung; Kim, Yong-Jin; Oh, Yun Kyu; Kim, Yon Su; Kim, Young Hoon; Lim, Chun Soo

    2016-01-01

    Background Pre-transplant cardiovascular (CV) risk factors affect the development of CV events even after successful kidney transplantation (KT). However, the impact of pre-transplant CV risk factors on allograft failure (GF) has not been reported. Methods and Findings We analyzed the graft outcomes of 2,902 KT recipients who were enrolled in a multi-center cohort from 1997 to 2012. We calculated the pre-transplant CV risk scores based on the Framingham risk model using age, gender, total cholesterol level, smoking status, and history of hypertension. Vascular disease (a composite of ischemic heart disease, peripheral vascular disease, and cerebrovascular disease) was noted in 6.5% of the patients. During the median follow-up of 6.4 years, 286 (9.9%) patients had developed GF. In the multivariable-adjusted Cox proportional hazard model, pre-transplant vascular disease was associated with an increased risk of GF (HR 2.51; 95% CI 1.66–3.80). The HR for GF (comparing the highest with the lowest tertile regarding the pre-transplant CV risk scores) was 1.65 (95% CI 1.22–2.23). In the competing risk model, both pre-transplant vascular disease and CV risk score were independent risk factors for GF. Moreover, the addition of the CV risk score, the pre-transplant vascular disease, or both had a better predictability for GF compared to the traditional GF risk factors. Conclusions In conclusion, both vascular disease and pre-transplant CV risk score were independently associated with GF in this multi-center study. Pre-transplant CV risk assessments could be useful in predicting GF in KT recipients. PMID:27501048

  11. The biological and biomechanical effects of irradiation on anterior spinal bone grafts in a canine model.

    PubMed

    Emery, S E; Brazinski, M S; Koka, A; Bensusan, J S; Stevenson, S

    1994-04-01

    We evaluated the effects of irradiation on the healing of anterior vertebral strut grafts with use of a canine model. Through a left thoracotomy, a partial corpectomy of the seventh thoracic vertebra and autogenous iliac strut-grafting from the sixth to the eighth thoracic levels were performed in twenty-two adult beagles. Four groups were established: Group I (control) received no irradiation, Group II received preoperative irradiation, Group III received postoperative irradiation that began on the third postoperative day, and Group IV received postoperative irradiation that began on the twenty-first postoperative day. The irradiation protocol was five treatments of 500 centigray three times a week for a total of 2500 centigray. Fluorochromes were administered at regular intervals postoperatively. The beagles were killed three months postoperatively, and non-destructive biomechanical testing was done to evaluate the stiffness of the construct. The quality of healing at the junctions of the graft with the sixth and eighth thoracic vertebrae, the degree of revascularization of the graft, and the amount of new-bone formation were evaluated histologically. Statistical evaluation of the biomechanical data revealed no significant difference in the stiffness of the construct between Groups I, II, and IV. The specimens from Group III were significantly less stiff than those from Group I (the control group) in torsion (p = 0.03) and left lateral bending (p = 0.04) and than those from Group II in flexion (p = 0.02) and left lateral bending (p = 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)

  12. Modification on liquid retention property of cassava starch by radiation grafting with acrylonitrile. I. Effect of γ-irradiation on grafting parameters

    NASA Astrophysics Data System (ADS)

    Kiatkamjornwong, S.; Chvajarernpun, J.; Nakason, C.

    1993-07-01

    Radiation modification on liquid retention properties of native cassava starch, gelatinized at 85°C, by graft copolymerization with acrylonitrile was carried out by mutual irradiation to gamma-rays. A thin aluminum foil was used to cover the inner wall of the reaction vessel, so that the homopolymer concentration was reduced to be less than 1.0% with a distilled water retention value of 665 g/g of the dry weight of the saponified grafted product. Confirmation of graft copolymerization and saponification reactions was made by the infrared spectrophotometric technique. The combined effect of radiation parameters in terms of an irradiation time and a dose rate to the total dose on the extent of the grafting reaction expressed in terms of grafting parameters which directly influenced liquid retention values was evaluated in conjunction with statistical analysis.

  13. Pre-transplant dialysis modality does not influence short- or long-term outcome in kidney transplant recipients: analysis of paired kidneys from the same deceased donor.

    PubMed

    Dipalma, Teresa; Fernández-Ruiz, Mario; Praga, Manuel; Polanco, Natalia; González, Esther; Gutiérrez-Solis, Elena; Gutiérrez, Eduardo; Andrés, Amado

    2016-09-01

    Previous studies have reported contradictory results regarding the effect of pre-transplant dialysis modality on the outcomes after kidney transplantation (KT). To minimize the confounding effect of donor-related variables, we performed a donor-matched retrospective comparison of 160 patients that received only one modality of pre-transplant dialysis (peritoneal dialysis [PD] and hemodialysis [HD] in 80 patients each) and that subsequently underwent KT at our center between January 1990 and December 2007. Cox regression models were used to evaluate the association between pre-transplant dialysis modality and primary study outcomes (death-censored graft survival and patient survival). To control for imbalances in recipient-related baseline characteristics, we performed additional adjustments for the propensity score (PS) for receiving pre-transplant PD (versus HD). There were no significant differences according to pre-transplant dialysis modality in death-censored graft survival (PS-adjusted hazard ratio [aHR]: 0.65; 95% confidence interval [95% CI]: 0.25-1.68) or patient survival (aHR: 0.58; 95% CI: 0.13-2.68). There were no differences in 10-year graft function or in the incidence of post-transplant complications either, except for a higher risk of lymphocele in patients undergoing PD (odds ratio: 4.31; 95% CI: 1.15-16.21). In conclusion, pre-transplant dialysis modality in KT recipients does not impact short- or long-term graft outcomes or patient survival.

  14. Pre-irradiation grafting of acrylonitrile onto chitin for adsorption of arsenic in water

    NASA Astrophysics Data System (ADS)

    Hanh, Truong Thi; Huy, Ha Thuc; Hien, Nguyen Quoc

    2015-01-01

    Radiation-induced grafting is an effective technique for preparation of novel materials. In this study, partially deacetylated chitin with deacetylation degree (DDA) of about 40% was graft-copolymerized with acrylonitrile (AN) by a γ-ray pre-irradiation method. The maximal grafting degree of AN onto pre-irradiated chitin at 25±1.2 kGy was 114% for AN concentration in dimethylformamide of 40% (v/v) at 70 °C for 8 h. The mixture ratio of 0.1 N NH2OH·HCl to 0.1 N NaOH was selected to be 7:3 (v/v) for amidoxime conversion of cyano-groups on grafted chitin (Chi-g-AN). The characteristics of modified chitin were depicted by the FT-IR spectra, BET area and SEM images. Adsorption equilibrium of As(III) onto Chi-g-AN converted amidoxime (Chi-g-AN-C) fits with the Langmuir model and the maximal adsorption capacity was 19.724 mg/g. The break-through times of As(III) on Chi-g-AN-C in column adsorption experiments increased with the increase in bed depths.

  15. Pre-Transplant Depression Is Associated with Length of Hospitalization, Discharge Disposition, and Survival after Liver Transplantation

    PubMed Central

    Rogal, Shari S.; Mankaney, Gautham; Udawatta, Viyan; Chinman, Matthew; Good, Chester B.; Zickmund, Susan; Bielefeldt, Klaus; Chidi, Alexis; Jonassaint, Naudia; Jazwinski, Alison; Shaikh, Obaid; Hughes, Christopher; Fontes, Paulo; Humar, Abhinav; DiMartini, Andrea

    2016-01-01

    Depression after liver transplantation has been associated with decreased survival, but the effects of pre-transplant depression on early and late post-transplant outcomes remain incompletely evaluated. We assessed all patients who had undergone single-organ liver transplantation at a single center over the prior 10 years. A diagnosis of pre-transplant depression, covariates, and the outcomes of interest were extracted from the electronic medical record. Potential covariates included demographics, etiology and severity of liver disease, comorbidities, donor age, graft type, immunosuppression, and ischemic times. In multivariable models adjusting for these factors, we evaluated the effect of pre-transplant depression on transplant length of stay (LOS), discharge disposition (home vs. facility) and long-term survival. Among 1115 transplant recipients with a median follow-up time of 5 years, the average age was 56±11 and MELD was 12±9. Nineteen percent of the study population had a history of pre-transplant depression. Pre-transplant depression was associated with longer LOS (median = 19 vs. 14 days, IRR = 1.25, CI = 1.13,1.39), discharge to a facility (36% vs. 25%, OR 1.70,CI = 1.18,2.45), and decreased survival (HR = 1.54,CI = 1.14,2.08) in this cohort, accounting for other potential confounders. In conclusion, pre-transplant depression was significantly associated with longer transplant length of stay, discharge to a facility, and mortality in this cohort. PMID:27820828

  16. Synthesis and characterisation of starch grafted superabsorbent via 10 MeV electron-beam irradiation.

    PubMed

    Zhang, Sufen; Wang, Wei; Wang, Haiyan; Qi, Wenyuan; Yue, Ling; Ye, Qingfu

    2014-01-30

    A starch-graft-polyacrylamide (St-g-PAM) superabsorbent crosslinked by N,N'-methyl bisacrylamide (MBA) was prepared using 10 MeV simultaneous electron beam irradiation at room temperature and subsequent alkaline hydrolysis. The effects of the irradiation dose, acryliamide-to-anhydroglucose unit (AM-to-AGU) ratio and crosslinker amount on the properties of the obtained polymers were evaluated. The structure of the graft copolymer was confirmed by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM). Optimisation treatments were carried out and found for a total dose of 8 kGy, an AM-to-AGU ratio of 4.5 mol mol(-1) and a crosslinker-to-AM ratio of 0.4%mol mol(-1). The obtained superabsorbent polymer showed the maximum absorptions of 1,452 gg(-1) and 83 gg(-1) for distilled water and saline solution, respectively (relative to its own dry weight). The results suggest 10 MeV electron beam irradiation is more efficient than γ-ray irradiation due to its higher energy and dose rate.

  17. Pre-irradiation induced emulsion co-graft polymerization of acrylonitrile and acrylic acid onto a polyethylene nonwoven fabric

    NASA Astrophysics Data System (ADS)

    Liu, Hanzhou; Yu, Ming; Ma, Hongjuan; Wang, Ziqiang; Li, Linfan; Li, Jingye

    2014-01-01

    A pre-irradiation induced emulsion co-graft polymerization method was used to introduce acrylonitrile and acrylic acid onto a PE nonwoven fabric. The use of acrylic acid is meant to improve the hydrophilicity of the modified fabric. The kinetics of co-graft polymerization were studied. The existence of polyacrylonitrile (PAN) and poly(acrylic acid) (PAAc) graft chains was proven by Fourier transform infrared spectroscopy (FTIR) analysis. The existence of the nitrile groups in the graft chains indicates that they are ready for further amidoximation and adsorption of heavy metal ions.

  18. Microfiltration membranes prepared from polyethersulfone powder grafted with acrylic acid by simultaneous irradiation and their pH dependence

    NASA Astrophysics Data System (ADS)

    Deng, Bo; Li, Jingye; Hou, Zhengchi; Yao, Side; Shi, Liuqing; Liang, Guoming; Sheng, Kanglong

    2008-07-01

    Polyethersulfone (PES) powder was grafted with acrylic acid (AAc) by simultaneous γ-ray irradiation. The kinetics of the radiation induced graft polymerization was studied and the grafted PES powder was characterized. Then, microfiltration (MF) membranes were prepared from PES-g-PAAc powder with different degrees of grafting (DG) under phase inversion method. The swelling behavior and the mean pore size of MF membranes were measured, and the filtration property was tested. The results showed that the pore size and the flux of MF membranes increased with the increase in DG. And, MF membranes' properties were dependent on the pH value.

  19. In vitro allograft irradiation prevents graft-versus-host disease in small-bowel transplantation

    SciTech Connect

    Lee, K.K.; Schraut, W.H.

    1985-04-01

    In small-bowel transplantation, the transfer of large numbers of donor lymphocytes with the intestinal allograft may provoke a lethal graft-versus-host reaction. The effectiveness of allograft irradiation in vitro as a method of preventing graft-versus-host disease (GVHD) was studied in a rat model of small-bowel transplantation, with the Lewis----Lewis X Brown Norway F1 hybrid strain combination. Cold harvested small-bowel allografts were irradiated immediately prior to heterotopic or orthotopic transplantation. Animals that had received heterotopic allografts irradiated with 0, 250, or 500 rad all died of GVHD after 14.4 +/- 3.0, 15.0 +/- 1.3, and 14.2 +/- 1.9 days, respectively. None of the animals that had received allografts treated with 1000 rad developed clinical or pathologic evidence of GVHD, however, and all survived for more than 6 months (P less than 0.001). Allograft function was studied in animals that underwent orthotopic transplantation. Recipients of nonirradiated orthotopic allografts all died of GVHD after 14.0 +/- 0.7 days, whereas recipients of allografts irradiated with 1000 rad all survived for more than 5 months (P less than 0.001). After 120 days, weight gain (51.8 +/- 11.7%), serum albumin (3.9 +/- 0.7 g/dl), serum triglycerides (67.0 +/- 24.3 mg/dl), CBC, and differential in these animals were not statistically different from those in either age-matched isograft recipients or normal animals, and when the rats were sacrificed, irradiated allografts showed no changes suggestive of radiation injury. These results indicate that irradiation of small-bowel allografts in vitro prevents development of GVHD, and that this can be achieved at a dose which does not cause injury to or malfunction of the allograft.

  20. Graft polymerization of guar gum with acryl amide irradiated by microwaves for colonic drug delivery.

    PubMed

    Shahid, Muhammad; Bukhari, Shazia Anwer; Gul, Yousra; Munir, Hira; Anjum, Fozia; Zuber, Mohammad; Jamil, Tahir; Zia, Khalid Mahmood

    2013-11-01

    This article is aimed to discuss the modification of guar gum through microwave irradiation by varying the time of irradiation. The characterization of the modified products was carried out using FTIR spectroscopic analysis. The FT-IR spectrum of the pure guar gum (GG) sample showed a broad peak at 3298 cm(-1) while the modified GG sample displayed a peak at 1541 cm(-1) which was absent in the crude sample. The X-ray diffraction (XRD) analysis confirmed the increase in crystallinity due to grafting of the sample with polyacrylamide (GG-g-PAM). Scanning electron microscope (SEM) images revealed that granular form of guar gum was changed into fibrillar structure after grafting. Thermo-gravimetric analysis of the modified samples was also carried out and discussed. The role of guar gum as a matrix for controlled release of drug triamcinolone was evaluated. The GG-acrylamide grafted samples presented a correlation between drug release and time of microwave exposure. The results revealed that such modified product has potential applications in colonic drug delivery system.

  1. Synthesis of perm-selective membranes by grafting acrylic acid into air-irradiated Teflon-FEP films

    NASA Astrophysics Data System (ADS)

    Bozzi, Annick; Chapiro, Adolphe

    Grafting acrylic acid into air-irradiated Teflon-FEP films was investigated. Pre-irradiation doses ranged from 0.5 to 10 kGy. Grafting occurred at 45 or 60°C. Homopolymerization inhibitors, ferrous ions or methylene blue, were added to the system. It was found that after completion of the reaction, within 40-100 min, membranes were obtained with very low electric resistivities. The influence of added inhibitors, pre-irradiation dose and grafting temperature was studied. From the results it is concluded that the initiating centers in air-irradiated Teflon-FEP are, on the one hand, peroxides of structure POOP', in which P is a polymeric radical and Pprime; a small fragment, and on the other trapped PO .2 radicals. The latter only react after losing their oxygen. In the presence of polymerization inhibitors, initiation involves a redox process which reduces the overall activation energy.

  2. Gas-phase and liquid-phase pre-irradiation grafting of AAc onto LDPE and HDPE films for pervaporation membranes

    NASA Astrophysics Data System (ADS)

    Zhigong, Rao; Guixiang, Li; Sugo, Takanobu; Okamoto, Jiro

    A study has been made on gas-phase and liquid-phase pre-irradiation grafting of acrylic acid onto LDPE and HDPE films for pervaporation membranes of ethanol-water mixtures. It was found that the degree of grafting, percent volume change of grafted membranes and length of grafting chains depend on the methods of grafting, crystal state of substrate films and diffusion rate of the monomer in the films. The pervaporation characteristics of grafted membranes is influenced directly by the surface hydrophilicity of grafted membranes, temperature of the feed, degree of grafting, crosslinking of grafted chains and alkaline metal ions in the functional groups. The potassium ion exchange membrane of HDPE synthesized by gas-phase grafting has better pervaporation efficiency. At 80 wt% ethanol in the feed, 25°C feed temperature and 70% degree of grafting a grafted membrane has a 0.65 kg/m 2h flux and a separation factor of 20.

  3. In vitro and in vivo study of He + ion irradiated collagen for development of small diameter stent graft material

    NASA Astrophysics Data System (ADS)

    Suzuki, Y.; Iwaki, M.; Takahashi, N.; Yotoriyama, T.; Kurotobi, K.; Ujiie, H.; Hori, T.

    2005-05-01

    Recently, stent graft technology for endovascular treatment of aortic dissections has made tremendous advances. It is now possible to apply this minimally invasive technique to a wider range of pathology. The aim of this study was to develop anti-thrombogenic coronary stent and graft materials using ion-beam technology. Our previous study indicted that collagen surfaces irradiated with He + ion at a fluence of 1 × 10 14 ions/cm 2 have excellent blood compatibility. The ion-beam-irradiated collagen grafts demonstrated a high anti-thrombogenicity and graft patency. 150 keV-He +-irradiated collagen with a fluence of 1 × 10 14 ions/cm 2 has the properties of anti-thrombogenicity and cell attachment. In vitro plasma protein adsorption was evaluated to investigate the mechanisms of anti-thrombogenicity of these surfaces. From these results, anti-thrombogenicity of the He +-irradiated collagen was caused by the reduction of the plasma protein adsorption, such as fibrinogen or von Willebrand factor, by ion-beam irradiation. Japanese white rabbits weighing 3-4.5 kg were used in this animal study. Collagen-coated graft material implanted with He + ions at a fluence of 1 × 10 14 ions/cm 2 exhibited excellent anti-thrombogenicity and demonstrated patency for one year.

  4. Separate effects of irradiation and of graft-versus-host reaction on rat mucosal mast cells.

    PubMed Central

    Cummins, A G; Munro, G H; Huntley, J F; Miller, H R; Ferguson, A

    1989-01-01

    T cell mediated immune responses in the gut can produce enteropathy and malabsorption. We have investigated the relevance of mucosal mast cells (MMC) to the mechanisms of this enteropathy by using graft-versus-host reaction (GvHR) in the rat as a model of mucosal delayed type hypersensitivity. Measurements of mucosal architecture, intraepithelial lymphocytes (IEL) and MMC counts were performed in control and experimental rats, and release of rat mast cell protease II (RMCPII) into the bloodstream was used as an index of MMC activation. In unirradiated rats, jejunal MMC count was increased on day 14 of the GvHR (mean 272/mm2 v 182 in controls, p less than 0.01), as was serum RMCPII (p less than 0.01). Irradiated rats (4.5 Gy, reconstituted with isogeneic spleen cells) had low counts of IEL and crypt hyperplasia seven to 14 days after irradiation. Irradiated rats with GvHR (induced by ip injection of parental strain spleen cells) and studied on days 7, 10 and 14, had significant enteropathy with longer crypts and higher CCPR than matched irradiated animals (p less than 0.05 on day 14 when compared with irradiation alone). Intraepithelial lymphocytes counts, however, reflected only the effect of radiation. Irradiation, with or without GvHR, led to the virtual disappearance of jejunal MMC, undetectable jejunal RMCPII and very low levels of RMCPII in serum (all p less than 0.01 when compared with unirradiated controls). These experiments show that there is a modest expansion in jejunal MMC in unirradiated rats with semiallogeneic GvHR, whereas irradiation, alone or associated with GvHR, profoundly depletes MMC for at least two weeks. The enteropathy of GvHR can evolve in the virtual absence of MMC. PMID:2707634

  5. Novel insights into pretransplant allosensitization in heart transplant recipients in the contemporary era of immunosuppression and rejection surveillance.

    PubMed

    Svobodova, Eva; Gazdic, Tomas; Kubanek, Milos; Vymetalova, Jevgenija; Voska, Ludek; Kment, Martin; Lanska, Vera; Kolesar, Libor; Urban, Marian; Netuka, Ivan; Pirk, Jan; Melenovsky, Vojtech; Kautzner, Josef; Slavcev, Antonij; Malek, Ivan

    2016-01-01

    Solid-phase assays (SPA) have facilitated detection and definition of antibodies to human leukocyte antigens (HLA) and major histocompatibility complex class I chain-related antigen A (MICA). However, clinical consequences of pretransplant SPA results in heart transplantation have been studied insufficiently in the current era of immunosuppression and rejection surveillance. Pretransplant sera, panel-reactive antibodies (PRA), pretransplant crossmatch, and clinical data were retrospectively analyzed in 264 adult heart transplant recipients. The specificity of HLA and MICA antibodies and C1q-binding activity of donor-specific antibodies (DSA) were defined using SPA. Pretransplant HLA antibodies were detected in 57 (22%) individuals, in 28 individuals (11%); these antibodies were DSA after transplant. Preformed DSA and elevated peak PRA were independent predictors of pathologic AMR, which occurred in 19 individuals (7%). The increasing number of DSA and the cumulative mean fluorescence intensity of DSA were associated with AMR. C1q-binding assay was a suboptimal predictor of AMR in our cohort. Pretransplant allosensitization and MICA antibodies were related neither to impaired graft survival nor to other adverse clinical events during a median follow-up of 39 months. Identification of preformed DSA by SPA, in addition to PRA monitoring, may predict AMR in the contemporary era of heart transplantation.

  6. Minor antigen graft-versus-host reactions revealed in irradiated spleen and popliteal lymph node assays

    SciTech Connect

    Claman, H.N.; Jaffee, B.D.

    1984-10-01

    The graft-versus-hot (GVH) reaction across minor (non-H-2) histocompatibility barriers was studied in mice, in vivo. To increase GVH potential and to mimic clinical bone marrow transplantation protocols, we modified the popliteal lymph node (PLN) and the splenomegaly assays by irradiating the recipients before they received allogeneic lymphoid cell suspensions. In several combinations across major (H-2), minor (non-H-2) and multiple minor (non-H-2 plus minor lymphocyte stimulation) barriers, increased recipient organ weight (a measure of GVH activity) was seen with irradiated F1 recipients of parental cells. The irradiated splenomegaly (x-splenomegaly) assay was more sensitive than the (x-PLN) assay, but both correlated with in vivo GVH experiments of the P----F1 variety. The x-splenomegaly test indicated histoincompatibility in a system (B10.D2----BALB/c) in which the primary in vitro mixed leukocyte reactions is nonreactive, but in which systemic GVH can be induced. The x-splenomegaly test should be useful in analyzing complex reactions involving minor histocompatibility antigens in vivo.

  7. Impaction bone grafting with freeze-dried irradiated bone. Part I. Femoral implant stability: cadaver experiments in a hip simulator.

    PubMed

    Cornu, Olivier; Bavadekar, Ashit; Godts, Bernard; Van Tomme, John; Delloye, Christian; Banse, Xavier

    2003-10-01

    Processed freeze-dried irradiated allografts seem to be used less than instead of fresh-frozen allografts for impaction bone grafting in revision hip arthroplasties. Although biologically acceptable, their use is discouraged because of their questionable mechanical properties following freeze-drying and irradiation procedures. To address this question, we impacted freeze-dried grafts in 6 cadaveric femurs and loaded with a cemented Charnley prosthesis. The routinely used fresh-frozen allografts were used as controls in the contralateral side. These constructs were compared simultaneously in a walking hip simulator for their stability during 900,000 loading cycles. The mechanical parameters were axial inducible displacement and subsidence of the implant. The former parameter was lower in the implant mounted on freeze-dried impacted grafts than that mounted on the fresh-frozen bone. The latter parameter was also lower in the freeze-dried group. At the end of the test, we found no implant loosening in either group and their 'pull out' resulted in cement-prosthesis debonding, which showed the mechanical integrity of the impacted grafts. Freeze-dried grafts provide more stable fixation of the stem than fresh-frozen morselized grafts, when tested in a hip simulator.

  8. Preparation of starch-poly-glutamic acid graft copolymers by microwave irradiation and the characterization of their properties

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Graft copolymers of waxy maize starch and poly-y-glutamic acid (PGA) were produced in an aqueous solution using microwave irradiation. The microwave reaction conditions were optimized with regard to temperature and pH. The temperature of 180 deg C and pH 7.0 were the best reaction conditions resulti...

  9. Preparation of starch-poly-glutamic acid graft copolymers by microwave irradiation and the characterization of their properties.

    PubMed

    Xu, Jingyuan; Krietemeyer, Elizabeth F; Finkenstadt, Victoria L; Solaiman, Daniel; Ashby, Richard D; Garcia, Rafael A

    2016-04-20

    Graft copolymers of waxy maize starch and poly-γ-glutamic acid (PGA) were produced in an aqueous solution using microwave irradiation. The microwave reaction conditions were optimized with regard to temperature and pH. The temperature of 180°C and pH7.0 were the best reaction conditions resulting in a PGA graft of 0.45% based on nitrogen analysis. The average graft content and graft efficiency for the starch-PGA graft copolymer prepared at 180°C and pH7.0 were 4.20% and 2.73%, respectively. The starch-PGA graft copolymer produced at 180°C and pH7.0 could absorb more than 20 times its own weight amount of water and form a gel. The preliminary rheology study revealed that the starch-PGA graft copolymer gel exhibited viscoelastic solid behavior while the control sample of waxy starch showed viscoelastic liquid behavior.

  10. Cranial grafting of stem cell-derived microvesicles improves cognition and reduces neuropathology in the irradiated brain

    PubMed Central

    Baulch, Janet E.; Acharya, Munjal M.; Allen, Barrett D.; Ru, Ning; Chmielewski, Nicole N.; Martirosian, Vahan; Giedzinski, Erich; Syage, Amber; Park, Audrey L.; Benke, Sarah N.; Parihar, Vipan K.; Limoli, Charles L.

    2016-01-01

    Cancer survivors face a variety of challenges as they cope with disease recurrence and a myriad of normal tissue complications brought on by radio- and chemotherapeutic treatment regimens. For patients subjected to cranial irradiation for the control of CNS malignancy, progressive and debilitating cognitive dysfunction remains a pressing unmet medical need. Although this problem has been recognized for decades, few if any satisfactory long-term solutions exist to resolve this serious unintended side effect of radiotherapy. Past work from our laboratory has demonstrated the neurocognitive benefits of human neural stem cell (hNSC) grafting in the irradiated brain, where intrahippocampal transplantation of hNSC ameliorated radiation-induced cognitive deficits. Using a similar strategy, we now provide, to our knowledge, the first evidence that cranial grafting of microvesicles secreted from hNSC affords similar neuroprotective phenotypes after head-only irradiation. Cortical- and hippocampal-based deficits found 1 mo after irradiation were completely resolved in animals cranially grafted with microvesicles. Microvesicle treatment was found to attenuate neuroinflammation and preserve host neuronal morphology in distinct regions of the brain. These data suggest that the neuroprotective properties of microvesicles act through a trophic support mechanism that reduces inflammation and preserves the structural integrity of the irradiated microenvironment. PMID:27044087

  11. Cranial grafting of stem cell-derived microvesicles improves cognition and reduces neuropathology in the irradiated brain.

    PubMed

    Baulch, Janet E; Acharya, Munjal M; Allen, Barrett D; Ru, Ning; Chmielewski, Nicole N; Martirosian, Vahan; Giedzinski, Erich; Syage, Amber; Park, Audrey L; Benke, Sarah N; Parihar, Vipan K; Limoli, Charles L

    2016-04-26

    Cancer survivors face a variety of challenges as they cope with disease recurrence and a myriad of normal tissue complications brought on by radio- and chemotherapeutic treatment regimens. For patients subjected to cranial irradiation for the control of CNS malignancy, progressive and debilitating cognitive dysfunction remains a pressing unmet medical need. Although this problem has been recognized for decades, few if any satisfactory long-term solutions exist to resolve this serious unintended side effect of radiotherapy. Past work from our laboratory has demonstrated the neurocognitive benefits of human neural stem cell (hNSC) grafting in the irradiated brain, where intrahippocampal transplantation of hNSC ameliorated radiation-induced cognitive deficits. Using a similar strategy, we now provide, to our knowledge, the first evidence that cranial grafting of microvesicles secreted from hNSC affords similar neuroprotective phenotypes after head-only irradiation. Cortical- and hippocampal-based deficits found 1 mo after irradiation were completely resolved in animals cranially grafted with microvesicles. Microvesicle treatment was found to attenuate neuroinflammation and preserve host neuronal morphology in distinct regions of the brain. These data suggest that the neuroprotective properties of microvesicles act through a trophic support mechanism that reduces inflammation and preserves the structural integrity of the irradiated microenvironment.

  12. Recipient pretransplant inosine monophosphate dehydrogenase activity in nonmyeloablative hematopoietic cell transplantation.

    PubMed

    Bemer, Meagan J; Risler, Linda J; Phillips, Brian R; Wang, Joanne; Storer, Barry E; Sandmaier, Brenda M; Duan, Haichuan; Raccor, Brianne S; Boeckh, Michael J; McCune, Jeannine S

    2014-10-01

    Mycophenolic acid, the active metabolite of mycophenolate mofetil (MMF), inhibits inosine monophosphate dehydrogenase (IMPDH) activity. IMPDH is the rate-limiting enzyme involved in de novo synthesis of guanosine nucleotides and catalyzes the oxidation of inosine 5'-monophosphate to xanthosine 5'-monophosphate (XMP). We developed a highly sensitive liquid chromatography-mass spectrometry method to quantitate XMP concentrations in peripheral blood mononuclear cells (PMNCs) isolated from the recipient pretransplant and used this method to determine IMPDH activity in 86 nonmyeloablative allogeneic hematopoietic cell transplantation (HCT) patients. The incubation procedure and analytical method yielded acceptable within-sample and within-individual variability. Considerable between-individual variability was observed (12.2-fold). Low recipient pretransplant IMPDH activity was associated with increased day +28 donor T cell chimerism, more acute graft-versus-host disease (GVHD), lower neutrophil nadirs, and more cytomegalovirus reactivation but not with chronic GVHD, relapse, nonrelapse mortality, or overall mortality. We conclude that quantitation of the recipient's pretransplant IMPDH activity in PMNC lysate could provide a useful biomarker to evaluate a recipient's sensitivity to MMF. Further trials should be conducted to confirm our findings and to optimize postgrafting immunosuppression in nonmyeloablative HCT recipients.

  13. Protected graft copolymer-formulated fibroblast growth factors mitigate the lethality of partial body irradiation injury

    PubMed Central

    Castillo, Gerardo M.; Nishimoto-Ashfield, Akiko; Jones, Cynthia C.; Kabirov, Kasim K.; Zakharov, Alexander; Lyubimov, Alexander V.

    2017-01-01

    We evaluated the mitigating effects of fibroblast growth factor 4 and 7 (FGF4 and FGF7, respectively) in comparison with long acting protected graft copolymer (PGC)-formulated FGF4 and 7 (PF4 and PF7, respectively) administered to C57BL/6J mice a day after exposure to LD50/30 (15.7 Gy) partial body irradiation (PBI) which targeted the gastrointestinal (GI) system. The PGC that we developed increased the bioavailability of FGF4 and FGF7 by 5- and 250-fold compared to without PGC, respectively, and also sustained a 24 hr presence in the blood after a single subcutaneous administration. The dose levels tested for mitigating effects on radiation injury were 3 mg/kg for the PF4 and PF7 and 1.5 mg each for their combination (PF4/7). Amifostine administered prior to PBI was used as a positive control. The PF4, PF7, or PF4/7 mitigated the radiation lethality in mice. The mitigating effect of PF4 and PF7 was similar to the positive control and PF7 was better than other mitigators tested. The plasma citrulline levels and hematology parameters were early markers of recovery and survival. GI permeability function appeared to be a late or full recovery indicator. The villus length and crypt number correlated with plasma citrulline level, indicating that it can act as a surrogate marker for these histology evaluations. The IL-18 concentrations in jejunum as early as day 4 and TPO levels in colon on day 10 following PBI showed statistically significant changes in irradiated versus non-irradiated mice which makes them potential biomarkers of radiation exposure. Other colon and jejunum cytokine levels are potentially useful but require larger numbers of samples than in the present study before their full utility can be realized. PMID:28207794

  14. Protected graft copolymer-formulated fibroblast growth factors mitigate the lethality of partial body irradiation injury.

    PubMed

    Castillo, Gerardo M; Nishimoto-Ashfield, Akiko; Jones, Cynthia C; Kabirov, Kasim K; Zakharov, Alexander; Lyubimov, Alexander V

    2017-01-01

    We evaluated the mitigating effects of fibroblast growth factor 4 and 7 (FGF4 and FGF7, respectively) in comparison with long acting protected graft copolymer (PGC)-formulated FGF4 and 7 (PF4 and PF7, respectively) administered to C57BL/6J mice a day after exposure to LD50/30 (15.7 Gy) partial body irradiation (PBI) which targeted the gastrointestinal (GI) system. The PGC that we developed increased the bioavailability of FGF4 and FGF7 by 5- and 250-fold compared to without PGC, respectively, and also sustained a 24 hr presence in the blood after a single subcutaneous administration. The dose levels tested for mitigating effects on radiation injury were 3 mg/kg for the PF4 and PF7 and 1.5 mg each for their combination (PF4/7). Amifostine administered prior to PBI was used as a positive control. The PF4, PF7, or PF4/7 mitigated the radiation lethality in mice. The mitigating effect of PF4 and PF7 was similar to the positive control and PF7 was better than other mitigators tested. The plasma citrulline levels and hematology parameters were early markers of recovery and survival. GI permeability function appeared to be a late or full recovery indicator. The villus length and crypt number correlated with plasma citrulline level, indicating that it can act as a surrogate marker for these histology evaluations. The IL-18 concentrations in jejunum as early as day 4 and TPO levels in colon on day 10 following PBI showed statistically significant changes in irradiated versus non-irradiated mice which makes them potential biomarkers of radiation exposure. Other colon and jejunum cytokine levels are potentially useful but require larger numbers of samples than in the present study before their full utility can be realized.

  15. Impaction bone grafting with freeze-dried irradiated bone. Part II. Changes in stiffness and compactness of morselized grafts: experiments in cadavers.

    PubMed

    Cornu, Olivier; Bavadekar, Ashit; Godts, Bernard; Van Tomme, John; Delloye, Christian; Banse, Xavier

    2003-10-01

    In the technique of impaction bone grafting, implant stability depends on the mechanical properties of the impacted morselized grafts. Although the procedure is usually performed with fresh-frozen femoral heads, there is still some concern about their supply and safety. Bone processing is a potential solution, but the mechanical properties of this material during and after impaction need to be determined. We used 6 osteoarthrotic femoral heads to prepare two paired batches of morselized bone. One batch was morselized and frozen. The other batch was chemically treated, morselized, freeze-dried and then gamma-irradiated. We impacted 18 samples from each batch in a contained cylinder. Freeze-dried bone grafts were tested after 30 minutes of rehydration. The changes in the compactness and stiffness of the material were monitored during the impaction. The compaction of the freeze-dried bone was faster than that of their fresh-frozen control. The maximal stiffness reached by both materials was the same (55 MPa), but the freeze-dried grafts required three to four times fewer impactions to achieve that stiffness. After 3, 10 and 50 impactions the freeze-dried bone was stiffer than the fresh-frozen bone. As it is easier to impact, the freeze-dried bone may be mechanically more efficient than the fresh-frozen bone in surgical conditions. Moreover, the processed bone meets the highest safety standards, as regards the risk of disease transmission.

  16. Mutual irradiation grafting on indigenous aramid fiber-3 in diethanolamine and epichlorohydrin and its effect on interfacially reinforced epoxy composite

    NASA Astrophysics Data System (ADS)

    Xing, Lixin; Liu, Li; Xie, Fei; Huang, Yudong

    2016-07-01

    The surface of indigenous aramid fiber-3 (IAF3) was decorated via mutual irradiation grafting process in diethanolamine (DEA) and epichlorohydrin (ECH), respectively, with the assist of high energy gamma rays. This modification method with great permeability produced the homogeneous and ameliorative AF3 surfaces, which were observed by the scanning electron microscopy (SEM) and atom forced microscopy (AFM). Enhanced surface free energy and reduced contact angles of irradiated AF3 verified the fabulous effectiveness of mutual irradiation without seriously injured tensile strength. The composites based on epoxy resin (ER) polymer as the matrix and irradiated IAF3 grafted DEA and ECH as the reinforcement. By capitalizing on the irradiated IAF3 which has higher wettability and adsorption on resin, the irradiated IAF3-ECH/ER composites exhibit admirable interfacial mechanical performance as compared to the pristine IAF3 contained composites. The interfacial shear strength (IFSS), interlaminar shear strength (ILSS) and flexural strength of composites were remarkable improved to 86.5, 60.13 and 511 MPa respectively, from the pristine IAF3/ER composite with IFSS of 65.9 MPa, ILSS of 48.1 MPa, and flexural strength of 479 MPa.

  17. Pretransplant identification of acute rejection risk following kidney transplantation.

    PubMed

    Lebranchu, Yvon; Baan, Carla; Biancone, Luigi; Legendre, Christophe; Morales, José Maria; Naesens, Maarten; Thomusch, Oliver; Friend, Peter

    2014-02-01

    Lack of an accepted definition for 'high immunological risk' hampers individualization of immunosuppressive therapy after kidney transplantation. For recipient-related risk factors for acute rejection, the most compelling evidence points to younger age and African American ethnicity. Recipient gender, body mass, previous transplantation, and concomitant infection or disease do not appear to be influential. Deceased donation now has only a minor effect on rejection risk, but older donor age remains a significant predictor. Conventional immunological markers (human leukocyte antigen [HLA] mismatching, pretransplant anti-HLA alloantibodies, and panel reactive antibodies) are being reassessed in light of growing understanding about the role of donor-specific antibodies (DSA). At the time of transplant, delayed graft function is one of the most clear-cut risk factors for acute rejection. Extended cold ischemia time (≥ 24 h) may also play a contributory role. While it is not yet possible to establish conclusively the relative contribution of different risk factors for acute rejection after kidney transplantation, the available data point to variables that should be taken into account at the time of transplant. Together, these offer a realistic basis for planning an appropriate immunosuppression regimen in individual patients.

  18. Immunological and clinical observations in diabetic kidney graft recipients pretreated with total-lymphoid irradiation

    SciTech Connect

    Waer, M.; Vanrenterghem, Y.; Roels, L.; Ang, K.K.; Bouillon, R.; Lerut, T.; Gruwez, J.; van der Schueren, E.; Vandeputte, M.; Michielsen, P.

    1987-03-01

    In a feasibility study, twenty patients with end-stage diabetic nephropathy were treated with fractionated total-lymphoid irradiation (TLI, mean dose 25 Gy), before transplantation of a first cadaveric kidney. During radiotherapy, only one patient had a serious side effect (bone marrow depression). After transplantation four patients died (one of a myocardial infarction, one of ketoacidosis, and two of infections occurring during treatment of rejection crises). One graft was lost because of chronic rejection. The other 15 patients have a functioning graft (mean follow-up 24 months) and receive low-dose prednisone alone (less than 10 mg/day, n = 11) or in conjunction with cyclosporine (n = 4) as maintenance immunosuppressive therapy. A favorable clinical outcome after TLI (no, or only one, steroid-sensitive rejection crisis) was significantly correlated with a high pre-TLI helper/suppressor lymphocyte ratio, a short interval between TLI and the time of transplantation, and the occurrence of functional suppressor cells early after TLI. The most striking immunological changes provoked by TLI consisted of a long-term depression of the mixed lymphocyte reaction and of the phytohemagglutinin, and Concanavalin A or pokeweed-mitogen-induced blastogenesis. A rapid and complete recovery of the natural killer cell activity was observed after TLI. A permanent inversion of the OKT4+ (T helper/inducer) over OKT8+ (T suppressor/cytotoxic) lymphocyte ratio was provoked by a decrease of the OTK4+ subpopulation, together with a supranormal recovery of the OKT8+ lymphocytes. A majority of the latter lymphocytes did also express the Leu 7 and the Leu 15 phenotype.

  19. Immunosuppressive Total Lymphoid Irradiation-Based Reconditioning Regimens Enable Engraftment After Graft Rejection or Graft Failure in Patients Treated With Allogeneic Hematopoietic Stem Cell Transplantation

    SciTech Connect

    Heinzelmann, Frank; Lang, Peter J.; Ottinger, Hellmut; Faul, Christoph; Bethge, Wolfgang; Handgretinger, Rupert; Bamberg, Michael; Belka, Claus

    2008-02-01

    Purpose: To retrospectively evaluate the efficacy of total lymphoid irradiation (TLI)-based reconditioning regimens in patients with graft failure or graft rejection after allogeneic hematopoietic stem cell transplantation. Methods and Materials: The results of 14 patients (7 adults and 7 children) with a variety of hematologic malignant diseases treated with a TLI-based reconditioning regimen with 7-Gy single-dose application plus anti-T-lymphocyte antibody OKT3 (n = 11) and/or antithymocyte globulin (n = 7)/fludarabine (n = 9), followed by an infusion of peripheral blood stem cells (n = 13) or bone marrow stem cells (n = 1) from related or unrelated donors, were retrospectively analyzed. Results: Of the 14 recipients, the data from 11 were evaluable for engraftment after TLI-based reconditioning because 3 adults died early (at Day 2, 5, and 15) after the second transplantation of infectious complications. Engraftment in 4 adults was seen after a median of 12 days (range, 10-18) and occurred after a median of 10 days (range, 9-32) in the 7 children. TLI-based reconditioning was well-tolerated with no severe toxicity. The median overall survival and disease-free survival for the whole cohort was 140 days (range, 5-1,268). After a median follow-up of 681 days, the disease-free survival and overall survival rate was 85.7% and 85.7%, respectively, in the children. Despite engraftment in the 4 remaining adults, 1 died of fatal graft-vs.-host disease, 1 of infectious complications, 1 of disease relapse, and 1 of acute respiratory distress syndrome. Conclusions: In patients with graft failure or graft rejection after allogeneic hematopoietic stem cell transplantation, TLI-based reconditioning regimens allow sustained engraftment, paralleled by a favorable toxicity profile, potentially leading to long-term survival.

  20. Effect of UV-irradiation intensity on graft polymerization of 2-methacryloyloxyethyl phosphorylcholine on orthopedic bearing substrate.

    PubMed

    Kyomoto, Masayuki; Moro, Toru; Yamane, Shihori; Hashimoto, Masami; Takatori, Yoshio; Ishihara, Kazuhiko

    2014-09-01

    Photoinduced grafting of 2-methacryloyloxyethyl phosphorylcholine (MPC) onto cross-linked polyethylene (CLPE) was investigated for its ability to reduce the wear of orthopedic bearings. We investigated the effect of UV-irradiation intensity on the extent of poly(MPC) (PMPC) grafting, and found that it increased with increasing intensity up to 7.5 mW/cm(2), and the remained fairly constant. It was found to be extremely important to carefully control the UV intensity, as at higher values, a PMPC gel formed via homopolymerization of the MPC, resulting in the formation of cracks at the interface of the PMPC layer and the CLPE substrate. When the CLPE was exposed to UV-irradiation during the graft polymerization process, some of its physical and mechanical properties were slightly changed due to cross-linking and scission effects in the surface region; however, the results of all of the tests exceed the lower limits of the ASTM standards. Modification of the CLPE surface with the hydrophilic PMPC layer increased lubrication to levels that match articular cartilage. The highly hydrated thin PMPC films mimicked the native cartilage extracellular matrix that covers synovial joint surface, acting as an extremely efficient lubricant, and providing high-wear resistance.

  1. Removal of reactive dyes from textile wastewater by immobilized chitosan upon grafted Jute fibers with acrylic acid by gamma irradiation

    NASA Astrophysics Data System (ADS)

    Hassan, Mahmoud S.

    2015-10-01

    Jute fibers were grafted with acrylic acid by gamma irradiation technique. Chitosan was immobilized upon the grafted Jute fibers to be used as an adsorbent for waste reactive dye. The treated Jute fibers were characterized by using of Fourier-transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM) and X-ray diffraction (XRD). The effect of Jute treatment on its thermal stability by using thermogravimetric analysis (TGA) and its mechanical properties were investigated. The adsorption isotherm and the different factors affecting the dye adsorption such as pH and contact time were also studied. It was found that the dye adsorption was enhanced in the low pH range and increased with increasing of the contact time, regardless of temperature change.

  2. Synthesis of poly(sulfobetaine methacrylate)-grafted chitosan under γ-ray irradiation for alamethicin assembly.

    PubMed

    Zhou, Yuan; Dong, Ping; Wei, Yanqi; Qian, Jun; Hua, Daoben

    2015-08-01

    Interaction between peptide and lipid membrane plays a major role in biological activity of membrane-active peptide. We describe here a new biocompatible polymeric assembly to support membrane peptide. Specifically, chitosan-graft-poly(sulfobetaine methacrylate) (CS-g-PSBMA) was synthesized for alamethicin assembly by controlled polymerization under γ-ray irradiation. The graft copolymer could self-assemble into micelles in distilled water for supporting alamethicin. The assembly of alamethicin with CS-g-PSBMA micelles in aqueous solutions was related with the ratio of alamethicin/CS-g-PSBMA: the more alamethicin, the smaller sizes of the hybrid complex. Moreover, alamethicin penetrated into the hydrophobic cores of CS-g-PSBMA micelles while displayed secondary helical conformation in the complex. The results indicate that CS-g-PSBMA assemblies can be used to support membrane peptide.

  3. Engraftment of allogeneic bone marrow without graft-versus-host disease in mongrel dogs using total lymphoid irradiation

    SciTech Connect

    Gottlieb, M.; Strober, S.; Hoppe, R.T.; Grumet, F.C.; Kaplan, H.S.

    1980-06-01

    We achieved long-term engraftment of unmatched bone marrow (BM) in dogs without graft-versus-host disease (GVHD) using a regimen of total lymphoid irradiation (TLI) which could be applied clinically. Twelve normal adult mongrel dogs were given TLI in 18 fractions of 100 rad each (total dose, 1800 rad) over 4 weeks to mantle and abdominal fields in continuity. Nine of the 12 were transfused with one or two random donor whole blood transfusions during the irradiation regimen to determine the risk of sensitization after the onset of immunosuppression. A mean (+- SD) of 0.71 +- 0.54 x 10/sup 9/ BM cells/kg of recipient body weight from unrelated sex-mismatched donors was infused within 24 h of the 18th irradiation fraction. Engraftment was assessed by demonstration of donor-type sex chromosomes in spontaneous metaphase spreads of recipient marrow aspirates, and by the appearance of donor-type red blood cells antigens (DEA) in the recipients' blood. Three untransfused and nine transfused recipients were shown to be stable mixed BM chimeras during a followup period of 2 to 11 months after transplantation. Blood transfusion during TLI did not result in graft rejection. We observed no clinical signs of acute or chronic GVHD. TLI has minimal toxicity when compared with conditioning regimens currently used in BM transplantation for aplastic anemia. Potential advantages of the TLI regimen include the opportunity to use unmatched marrow donors and protection from GVHD.

  4. Preparation of metal adsorbent from poly(methyl acrylate)-grafted-cassava starch via gamma irradiation

    NASA Astrophysics Data System (ADS)

    Suwanmala, Phiriyatorn; Hemvichian, Kasinee; Hoshina, Hiroyuki; Srinuttrakul, Wannee; Seko, Noriaki

    2012-08-01

    Metal adsorbent containing hydroxamic acid groups was successfully synthesized by radiation-induced graft copolymerization of methyl acrylate (MA) onto cassava starch. The optimum conditions for grafting were studied in terms of % degree of grafting (Dg). Conversion of the ester groups present in poly(methyl acrylate)-grafted-cassava starch copolymer into hydroxamic acid was carried out by treatment with hydroxylamine (HA) in the presence of alkaline solution. The maximum percentage conversion of the ester groups of the grafted copolymer, % Dg=191 (7.63 mmol/g of MA), into the hydroxamic groups was 70% (5.35 mmol/g of MA) at the optimum condition. The adsorbent of 191%Dg had total adsorption capacities of 2.6, 1.46, 1.36, 1.15 and 1.6 mmol/g-adsorbent for Cd2+, Al3+, UO22+, V5+ and Pb2+, respectively, in the batch mode adsorption.

  5. Grafting of neural stem and progenitor cells to the hippocampus of young, irradiated mice causes gliosis and disrupts the granule cell layer

    PubMed Central

    Sato, Y; Shinjyo, N; Sato, M; Osato, K; Zhu, C; Pekna, M; Kuhn, H G; Blomgren, K

    2013-01-01

    Ionizing radiation persistently reduces the pool of neural stem and progenitor cells (NSPCs) in the dentate gyrus (DG) of the hippocampus, which may explain some of the learning deficits observed in patients treated with radiotherapy, particularly pediatric patients. A single dose of 8 Gy irradiation (IR) was administered to the brains of postnatal day 14 (P14) C57BL/6 mice and 1.0 × 105 bromodeoxyuridine-labeled, syngeneic NSPCs were injected into the hippocampus 1 day, 1 week or 6 weeks after IR. Cell survival and phenotype were evaluated 5 weeks after grafting. When grafted 1 day post-IR, survival and neuronal differentiation of the transplanted NSPCs were lower in irradiated brains, whereas the survival and cell fate of grafted cells were not significantly different between irradiated and control brains when transplantation was performed 1 or 6 weeks after IR. A young recipient brain favored neuronal development of grafted cells, whereas the older recipient brains displayed an increasing number of cells developing into astrocytes or unidentified cells. Injection of NSPCs, but not vehicle, induced astrogliosis and reduced thickness of the dorsal blade of the GCL after 5 months. In summary, we demonstrate that age and interval between IR and grafting can affect survival and differentiation of grafted NSPCs. The observed long-term gliosis and degeneration warrant caution in the context of NSPC grafting for therapeutical purposes. PMID:23598403

  6. A mild method of amine-type adsorbents syntheses with emulsion graft polymerization of glycidyl methacrylate on polyethylene non-woven fabric by pre-irradiation

    NASA Astrophysics Data System (ADS)

    Ma, Hongjuan; Yao, Side; Li, Jingye; Cao, Changqing; Wang, Min

    2012-09-01

    A mild pre-irradiation method was used to graft glycidyl methacrylate (GMA) onto polyethylene (PE) non-woven fabric (NF). The polymer was irradiated by electron beam in air atmosphere at room temperature. The degree of grafting (Dg) was determined as a function of reaction time, absorbed dose, monomer concentration and temperature. After 30 kGy irradiation, with 5% GMA, surfactant Tween 20 (Tw-20) of 0.5% at 55 °C for 15 min, the trunk polymer was made grafted with a Dg of 150%. Selected PE-g-PGMA of different Dg was modified with aminated compounds such as ethylenediamine (EDA), diethylenetriamine (DETA), triethylenetetramine (TETA) and tetraethylenepentamine (TEPA). The obtained amine-type adsorbents were prepared to remove copper and uranium ions from solution. It was shown that at least 90% of copper and 60% of uranium with the initial concentration from 3 to 1000 ppb can be removed from water.

  7. Emulsion graft polymerization of 4-chloromethylstyrene on kenaf fiber by pre-irradiation method

    NASA Astrophysics Data System (ADS)

    Mohamed, Nor Hasimah; Tamada, Masao; Ueki, Yuji; Seko, Noriaki

    2013-01-01

    The stability of micelle size in 3% 4-chloromethylstyrene (CMS), 0.3% Tween 20 in water emulsion over time was studied using a static light scattering. It was found that the micelle diameter decreased with storage time and temperature. The influence of micelle size over time was then explored by adjusting the ratio of CMS to Tween 20 (10:1, 10:2, 10:4) at CMS concentration of 0.2-5.0%. It was found that the increase in average micelle diameter resulted in a decreased in the stability of CMS emulsion. Graft polymerization of CMS on kenaf fiber was carried out in emulsion with 350 nm micelle at various CMS concentrations at a dose of 150 kGy. It was found that the degree of grafting (Dg) was strongly dependent on the monomer concentration and time. However, the increase in micelles diameter from 250 nm to 500 nm resulted in the increased in Dg from 3% to 153%. This extraordinary result led us to investigate the micelle size distributions of CMS emulsion during graft polymerization. It was found that the diameter of micelle decreased rapidly to 100 nm within 2 h. It was discovered from digital photomicrography the existence of multiple emulsions in the CMS emulsion. It was proposed that the enhancement of grafting yield is governed by emulsion breakdown mechanisms through radical effect during radiation induced graft polymerization.

  8. Enhanced wear resistance of orthopaedic bearing due to the cross-linking of poly(MPC) graft chains induced by gamma-ray irradiation.

    PubMed

    Kyomoto, Masayuki; Moro, Toru; Miyaji, Fumiaki; Konno, Tomohiro; Hashimoto, Masami; Kawaguchi, Hiroshi; Takatori, Yoshio; Nakamura, Kozo; Ishihara, Kazuhiko

    2008-02-01

    We assumed that the extra energy supplied by gamma-ray irradiation produced cross-links in 2-methacryloyloxyethyl phosphorylcholine (MPC) polymer grafted cross-linked polyethylene (CLPE-g-MPC) and investigated its effects on the tribological properties of CLPE-g-MPC. In this study, we found that the gamma-ray irradiation produced cross-links in three kinds of regions of CLPE-g-MPC: poly(MPC) layer, CLPE-MPC interface, and CLPE substrate. The dynamic coefficient of friction of CLPE-g-MPC slightly increased with increasing irradiation doses. After the simulator test, both the nonsterilized and gamma-ray sterilized CLPE-g-MPC cups exhibited lower wear than the untreated CLPE ones. In particular, the gamma-ray sterilized CLPE-g-MPC cups showed extremely low and stable wear. As for the nonsterilized CLPE-g-MPC cups, the weight change varied with each cup. When the CLPE surface is modified by poly(MPC) grafting, the MPC graft polymer leads to a significant reduction in the sliding friction between the surfaces that are grafted because water thin films formed can behave as extremely efficient lubricants. Such a cross-link of poly(MPC) slightly increases the friction of CLPE by gamma-ray irradiation but provides a stable wear resistant layer on the friction surface. The cross-links formed by gamma-ray irradiation would give further longevity to the CLPE-g-MPC cups.

  9. Irradiation mediated synthesis of a superabsorbent hydrogel network based on polyacrylamide grafted onto salep

    NASA Astrophysics Data System (ADS)

    Bardajee, Ghasem Rezanejade; Pourjavadi, Ali; Soleyman, Rouhollah; Sheikh, Nasrin

    2008-09-01

    The synthesis and swelling behavior of a new superabsorbent hydrogel based on natural salep grafted with polyacrylamide is described. The new biopolymer was synthesized via simultaneous crosslinking and graft copolymerization of acrylamide monomer onto a salep backbone using radiochemical methods. Various parameters such as relative contents of salep and acrylamide, as well as total dose of γ-rays were examined. The best synthesis condition is reported and a mechanism for superabsorbent hydrogel formation suggested. Factors affecting the swelling behavior of hydrogel were also studied.

  10. Preparation and characterization of poly(methyl methacrylate) and poly(maleic anhydride-co-diallyl phthalate) grafted carbon black through γ-ray irradiation

    NASA Astrophysics Data System (ADS)

    Bo, Yang; Cui, Jiayang; Cai, Yangben; Xu, Shiai

    2016-02-01

    In this study, the grafting polymerization of methyl methacrylate (MMA) monomer and maleic anhydride/diallyl phthalate (MAH/DAP) co-monomer onto the surface of carbon black (CB) were carried out at room temperature and normal pressure by γ-ray irradiation. The surface chemistry of grafted CBs were characterized by infrared spectroscopy (IR), thermo-gravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS). The results show that there are some remanent polymers on the surface of modified CBs after extract for 48 h, indicating that poly(methyl methacrylate) (PMMA) and poly(MAH-co-DAP) have been successfully grafted onto the surface of CB without using initiator due to the high energy of γ-ray irradiation. Dynamic light scattering (DLS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) reveal that the grafted CBs have smaller average aggregate size and better dispersibility than that of CB in absolute ethanol. In addition, it was found that the amount of oxygen groups and the irradiation doses/dose rates have little effect on the grafting degree of CB.

  11. Performance of membrane electrode assemblies based on proton exchange membranes prepared by pre-irradiation induced grafting

    NASA Astrophysics Data System (ADS)

    Li, Jingye; Matsuura, Akio; Kakigi, Tomoyuki; Miura, Takaharu; Oshima, Akihiro; Washio, Masakazu

    Proton exchange membranes (PEMs) were prepared by pre-irradiation induced grafting of styrene (S) or styrene/divinylbenzene (S/DVB) into the radiation-crosslinked polytetrafluoroethylene (RX-PTFE) films and then sulfonated. The thicknesses of the obtained PEMs were lower than 20 μm and the ion exchange capacity (IEC) values were around 2 meq g -1. The surfaces of the PEMs and carbon electrodes were coated with Nafion ® dispersion, and then membrane electrode assembles (MEAs) were prepared by hot-pressing them together. A MEA based on a Nafion ® 112 membrane was also prepared under same procedure for comparison. The performances of the MEAs in a single cell were tested under different cell temperatures and humidifications. Electrochemical impedance spectra (EIS) were measured with ac frequencies which ranged from 100 kHz to 1 Hz at a dc density of 0.5 A cm -2. The obtained impedance curves in Nyquist representation were semicircular.

  12. Preparation and characterization of mono-sheet bipolar membranes by pre-irradiation grafting method for fuel cell applications

    NASA Astrophysics Data System (ADS)

    Guan, Yingjie; Fang, Jun; Fu, Tao; Zhou, Huili; Wang, Xin; Deng, Zixiang; Zhao, Jinbao

    2016-09-01

    A new method for the preparation of the mono-sheet bipolar membrane applied to fuel cells was developed based on the pre-irradiation grafting technology. A series of bipolar membranes were successfully prepared by simultaneously grafting of styrene onto one side of the poly(ethylene-co-tetrafluoroethylene) base film and 1-vinylimidazole onto the opposite side, followed by the sulfonation and alkylation, respectively. The chemical structures and microstructures of the prepared membranes were investigated by ATR-FTIR and SEM-EDS. The TGA measurements demonstrated the prepared bipolar membranes have reasonable thermal stability. The ion exchange capacity, water uptake and ionic conductivity of the membranes were also characterized. The H2/O2 single fuel cells using these membranes were evaluated and revealed a maximum power density of 107 mW cm-2 at 35 °C with unhumidified hydrogen and oxygen. The preliminary performances suggested the great prospect of these membranes in application of bipolar membrane fuel cells.

  13. Kinetics of a methyl methacrylate polymerization initiated by the stable free radicals in irradiated polytetrafluoroethylene and properties of the resultant graft polymer

    SciTech Connect

    Donato, K.A.E.

    1987-01-01

    The kinetics of the polymerization of methyl methacrylate (MMA) initiated by the stable free radicals in commercially available irradiated polytetrafluoroethylene micropowder and the rheological, thermal, chemical, and mechanical properties of the resultant graft polymer are described. Test tube runs using different ratios of MMA to PTFE were made to determine the feasibility of the reaction and optimum reaction conditions. The amount of graft produced was equal to the weight gain of the solids after removal of the adventitious homopolymer by extraction in acetone. Test quantities of material were produced in a 500 milliliter agitated reactor. A higher ratio of PTFE to excess MMA and longer reaction times result in higher conversion in test tubes. A kinetic model was developed to relate the original concentration of PTFE free radical to the amount of MMA polymer. Graft polymer containing PTFE micropowder, PMMA graft, and PMMA homopolymer in a ratio of 18:5:1 was used for property characterization. The graft material extrudes well at 513K and has a viscosity comparable to that of PMMA homopolymer. The material is stable upon re-extrusion. DSC thermograms show that the heat of transition of the PTFE melting peak is proportional to the amount of PTFE in the sample. Good solvents for PMMA are detrimental to the structural integrity of the graft extrudate; heat treatment improves the chemical resistance. The PTFE block controls the mechanical properties of the graft.

  14. In vitro hemocompatibility of sulfonated polypropylene non-woven fabric prepared via a facile γ-ray pre-irradiation grafting method

    NASA Astrophysics Data System (ADS)

    Li, Rong; Wu, Guozhong; Ye, Yin

    2015-11-01

    Sulfonated polypropylene non-woven fabric (PPNWF) was successfully prepared via γ-ray pre-irradiation-induced graft polymerization of sodium styrenesulfonate (SSS) and acrylamide (AAm). The effect of pre-irradiation dose, reaction temperature, reaction time and concentration of binary monomer on the degree of grafting (DG) was studied. The chemical structure of the original and modified PPNWF materials were investigated by attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS) to confirm the successful introduction of sulfonated (sbnd SO3-) group. The wettability was examined via measurement of de-ionized water adsorption percentage, which demonstrated that the hydrophilicity of PPNWF was greatly enhanced after graft modification. A little amount of bovine serum albumin (BSA) adsorption and nearly no platelet adhesion on the surface of modified PPNWF and low hemolytic ratio of the modified PPNWF revealed that the sulfonated PPNWF exhibited good hemocompatibility. Besides, blood clotting time measurement indicated that the anticoagulant property of PPNWF was effectively enhanced via SSS modification. Consequently, the hydrophilicity, in vitro hemocompatibility and anticoagulant effect of PPNWF were significantly improved by γ-ray pre-irradiation-induced graft polymerization of SSS.

  15. The Use Of Laser Irradiation To Stimulate Adipose Derived Stem Cell Proliferation And Differentiation For Use In Autologous Grafts

    NASA Astrophysics Data System (ADS)

    Abrahamse, Heidi

    2009-09-01

    fluences on ADSC viability and proliferation. This paper reviews the development of MSCs as potential therapeutic interventions such as autologous grafts as well as the contribution of low intensity laser irradiation on the maintenance of these cells.

  16. Gamma-ray co-irradiation induced graft polymerization of NVP and SSS onto polypropylene non-woven fabric and its blood compatibility

    NASA Astrophysics Data System (ADS)

    Li, Rong; Wang, Hengdong; Wang, Wenfeng; Ye, Yin

    2013-10-01

    Sodium styrenesulfonate was grafted onto PPNWF via γ-ray co-irradiation method with the existence of N-vinyl-2-pyrrolidone. The effect of absorbed dose, dose rate and concentration of binary monomer on the degree of grafting was investigated. The surface chemical change was characterized by attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS). The wettability was characterized through the measurement of adsorption percentage of water and phosphate buffer solution (PBS). The result demonstrated that the grafted poly(NVP-co-SSS) chains can improve the hydrophilicity of PPNWF. Furthermore, the modified PPNWF has good blood compatibility, such as low hemolysis rate, low platelet adhesion and effectively extending the blood coagulation times. Consequently, hydrophilicity and hemocompatibility of PPNWF were greatly enhanced by the immobilization of poly(NVP-co-SSS) chains.

  17. Surface grafting of a thermoplastic polyurethane with methacrylic acid by previous plasma surface activation and by ultraviolet irradiation to reduce cell adhesion.

    PubMed

    Alves, P; Pinto, S; Kaiser, Jean-Pierre; Bruinink, Arie; de Sousa, Hermínio C; Gil, M H

    2011-02-01

    The material performance, in a biological environment, is mainly mediated by its surface properties and by the combination of chemical, physical, biological, and mechanical properties required, for a specific application. In this study, the surface of a thermoplastic polyurethane (TPU) material (Elastollan(®)1180A50) was activated either by plasma or by ultra-violet (UV) irradiation. After surface activation, methacrylic acid (MAA) was linked to the surface of TPU in order to improve its reactivity and to reduce cell adhesion. Grafted surfaces were evaluated by X-ray photoelectron spectroscopy (XPS), by atomic force microscopy (AFM) and by contact angle measurements. Blood compatibility studies and cell adhesion tests with human bone marrow cells (HBMC) were also performed. If was found that UV grafting method led to better results than the plasma activation method, since cell adhesion was reduced when methacrylic acid was grafted to the TPU surface by UV.

  18. The graft-versus-host reaction and immune function. II. Recruitment of pre-T-cells in vivo by graft-versus-host-induced dysplastic thymuses following irradiation and bone marrow treatment

    SciTech Connect

    Seddik, M.; Seemayer, T.A.; Lapp, W.S.

    1984-03-01

    The graft-versus-host (GVH) reaction induces thymic dysplasia and an arrest in T cell differentiation. Studies were performed to test the effect of irradiation and reconstitution with bone marrow on GVH-induced thymic dysplasia and T cell differentiation. GVH reactions were induced in CBAxAF1 adult mice by the injection of A strain lymphoid cells. All GVH-reactive mice were immunosuppressed by day 7 after GVH induction and thymic dysplasia was evident by day 24. Forty days after the induction of the GVH reaction the mice were irradiated (850 rads) and repopulated with 10-15 X 10(6) syngeneic or parental bone marrow cells. Thirty days after irradiation and bone marrow reconstitution, GVH-reactive mice were used for histological and functional studies. These mice displayed near-normal thymus morphology with scattered epithelial cells in the medulla, and normal numbers of Thy-1-positive cells. Donor cells had totally repopulated thymuses of irradiated bone marrow reconstituted mice by day 19 after irradiation. T helper cell function did not recover in the reconstituted mice. These results suggest that (1) the process responsible for GVH-induced thymic dysplasia is radiosensitive, and (2) the thymus has the potential to regenerate a normal structure, but fails to regain normal function.

  19. Surface characterization of poly(N-isopropylacrylamide) grafted tissue culture polystyrene by electron beam irradiation, using atomic force microscopy, and X-ray photoelectron spectroscopy.

    PubMed

    Akiyama, Yoshikatsu; Kushida, Ai; Yamato, Masayuki; Kikuchi, Akihiko; Okano, Teruo

    2007-03-01

    To understand features of polymers grafted by electron beam (EB) irradiation method, we investigated topology of poly(N-isopropylacrylamide) (PIPAAm) grafted tissue culture polystyrene (TCPS) (PIPAAm-TCPS) prepared by EB irradiation, using atomic force microscopy (AFM) in air and under aqueous conditions. Furthermore, surfaces properties of PIPAAm-TCPS surfaces before and after cell culture were also examined for evaluation of functionality of the surface as biomaterials, using XPS analysis. Three types of PIPAAm-TCPSs with different graft densities (1.0+/-0.1, 1.6+/-0.1, and 2.0+/-0.1 microg/cm2 of the grafted) were obtained (abbreviated as 11PIPAAm-, 16PIPAAm-, and 20PIPAAm-TCPS) by using different initial monomer concentration (20, 55, and 65 wt%). Contact angles (costheta value) of the surfaces increased with an increase in density of the grafted polymer. AFM observation in air clearly revealed that original TCPS surface possesses scratched and grooved topology (ca. 10 nm height of the scratch), while PIPAAm-TCPSs surfaces exhibited nanoordered PIPAAm particle-like domains. The size of the particles also increased proportionally initial IPAAm monomer concentration. The 11PIPAAm-and 16PIPAAm-TCPS surfaces having ca. 10-30 nm and ca. 40-50 nm size of the particles also displayed scratched and grooved topology featured in basal TCPS. However, the larger sizes of the particles (ca. 40-100 nm) formed on 20PIPAAm-TCPS surfaces adequately conceals the topological feature of the basal TCPS surfaces. The AFM images indicate that the graft polymer is as ultra thin as the scratch and grooves featured on basal TCPS are discernible, and the grafted PIPAAm layer become thicker with an increase of the monomer concentration. For 16PIPAAm-TCPS surfaces, the nanoordered particles were also observable in aqueous conditions at 20 degrees C and 37 degrees C. Comparison between the images obtained at 20 degrees C and 37 degrees C suggest that the domains are not likely to exhibit

  20. Experimental studies of immunologically mediated enteropathy. Development of cell mediated immunity and intestinal pathology during a graft-versus-host reaction in irradiated mice.

    PubMed Central

    Mowat, A M; Felstein, M V; Borland, A; Parrott, D M

    1988-01-01

    The intestinal component of a graft-versus-host reaction (GvHR) provides a useful experimental model to elucidate the pathogenesis of clinical enteropathies which cause villus atrophy and crypt hyperplasia and which are associated with a local immune response. One to three days after induction of GvHR in heavily irradiated (CBAxBALB/c)F1 mice, a proliferative form of enteropathy developed. Compared with controls, these mice had increased counts of jejunal intraepithelial lymphocytes and had a four-fold increase in crypt cell production rate as well as an increase in crypt length. These changes were accompanied by a marked enhancement of splenic natural killer cell activity. After day three, the crypt cell production rate fell to zero and cytotoxic T lymphocytes (CTL) which could lyse targets of host origin appeared. In parallel, mice with GvHR developed significant villus shortening and their clinical condition deteriorated. Further experiments showed that increased counts of intraepithelial lymphocytes, villus atrophy and crypt hyperplasia also occurred in grafts of fetal CBA intestine implanted under the kidney capsule of (CBAxBALB/c)F1 mice with GvHR. As these grafts are syngeneic to the injected CBA spleen cells, they should not be attacked by anti-host cytotoxic T lymphocytes. We suggest that the proliferative and destructive components of enteropathy in GvHR are caused by lymphokines released by an anti-host delayed type hypersensitivity reaction. PMID:3294125

  1. Reconstruction of irradiated bone segmental defects with a biomaterial associating MBCP+(R), microstructured collagen membrane and total bone marrow grafting: an experimental study in rabbits.

    PubMed

    Jégoux, Franck; Goyenvalle, Eric; Cognet, Ronan; Malard, Olivier; Moreau, Francoise; Daculsi, Guy; Aguado, Eric

    2009-12-15

    The bone tissue engineering models used today are still a long way from any oncologic application as immediate postimplantation irradiation would decrease their osteoinductive potential. The aim of this study was to reconstruct a segmental critical size defect in a weight-bearing bone irradiated after implantation. Six white New Zealand rabbits were immediately implanted with a biomaterial associating resorbable collagen membrane EZ(R) filled and micro-macroporous biphasic calcium phosphate granules (MBCP+(R)). After a daily schedule of radiation delivery, and within 4 weeks, a total autologous bone marrow (BM) graft was injected percutaneously into the center of the implant. All the animals were sacrificed at 16 weeks. Successful osseous colonization was found to have bridged the entire length of the defects. Identical distribution of bone ingrowth and residual ceramics at the different levels of the implant suggests that the BM graft plays an osteoinductive role in the center of the defect. Periosteum-like formation was observed at the periphery, with the collagen membrane most likely playing a role. This model succeeded in bridging a large segmental defect in weight-bearing bone with immediate postimplantation fractionated radiation delivery. This has significant implications for the bone tissue engineering approach to patients with cancer-related bone defects.

  2. Natural resistance of lethally irradiated F1 hybrid mice to parental marrow grafts is a function of H-2/Hh-restricted effectors

    SciTech Connect

    Daley, J.P.; Nakamura, I.

    1984-04-01

    The natural resistance of F1 hybrid mice against parental bone marrow grafts is thought to be mediated by natural killer (NK)-like effector cells. However, unlike the NK cell activity against a wide range of tumors and normal cells, hybrid resistance is characterized by the immunogenetic specificity controlled by a set of unique noncodominant genes denoted as Hh. Two alternative hypotheses can account for the specificity. Thus, the specificity may reflect either the Hh restriction of effectors or the Hh gene control of mechanisms regulating non-Hh-restricted effector activity. In this study, therefore, we tested the recognition specificity of putative effectors mediating hybrid resistance in lethally irradiated H-2b/d and H-2b/k F1 hybrid mice to the engraftment of parental H-2b bone marrow. As a direct means of defining the effector specificity, rejection of parental bone marrow grafts was subjected to competitive inhibition in situ by irradiated tumor cells. Of the 16 independent lines of lymphoma and other hemopoietic tumor cells tested, the ability to inhibit hybrid resistance was the exclusive property of all tumors derived from mice homozygous for the H-2Db region, regardless of whether the tumor cells were susceptible or resistant to NK cell-mediated cytotoxicity in vitro. Four cell lines heterozygous for the H-2Db were noninhibitory, including one that is susceptible to natural killing. Pretreatment of the F1 hosts with an interferon inducer augmented the resistance with no alteration in the recognition specificity of effector cells. Therefore, natural resistance to parental H-2b bone marrow grafts was mediated by effectors restricted by the H-2Db/Hh-1b gene(s), and not by the nonrestricted NK cells detectable in conventional in vitro assays.

  3. The role of pattern-recognition receptors in graft-versus-host disease and graft-versus-leukemia after allogeneic stem cell transplantation.

    PubMed

    Heidegger, Simon; van den Brink, Marcel R M; Haas, Tobias; Poeck, Hendrik

    2014-01-01

    Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is the only treatment with curative potential for certain aggressive hematopoietic malignancies. Its success is limited by acute graft-versus-host disease (GVHD), a life-threatening complication that occurs when allo-reactive donor T cells attack recipient organs. There is growing evidence that microbes and innate pattern-recognition receptors (PRRs) such as toll-like receptors (TLR) and nod-like receptors (NLR) are critically involved in the pathogenesis of acute GVHD. Currently, a widely accepted model postulates that intensive chemotherapy and/or total-body irradiation during pre-transplant conditioning results in tissue damage and a loss of epithelial barrier function. Subsequent translocation of bacterial components as well as release of endogenous danger molecules stimulate PRRs of host antigen-presenting cells to trigger the production of pro-inflammatory cytokines (cytokine storm) that modulate T cell allo-reactivity against host tissues, but eventually also the beneficial graft-versus-leukemia (GVL) effect. Given the limitations of existing immunosuppressive therapies, a better understanding of the molecular mechanisms that govern GVHD versus GVL is urgently needed. This may ultimately allow to design modulators, which protect from GvHD but preserve donor T-cell attack on hematologic malignancies. Here, we will briefly summarize current knowledge about the role of innate immunity in the pathogenesis of GVHD and GVL following allo-HSCT.

  4. New CO2 adsorbent containing aminated poly(glycidyl methacrylate) grafted onto irradiated PE-PP nonwoven sheet

    NASA Astrophysics Data System (ADS)

    Mahmoud Nasef, Mohamed; Abbasi, Ali; Ting, T. M.

    2014-10-01

    A new CO2 adsorbent containing triethylamine (TEA) was prepared by radiation induced grafting of glycidyl methacrylate (GMA) onto polyethylene coated polypropylene (PE-PP) non-woven sheet followed by amination reaction. The degree of grafting (DOG%) was controlled by variation of monomer concentration and absorbed dose. The incorporation of aminated poly(GMA) was investigated by Fourier transform infrared (FTIR) and scanning electron microscope (SEM). The adsorbent with DOG of 350% and amination yield of 60% exhibited CO2 adsorption capacity of 4.52 mol/kg at ambient temperature and pressure.

  5. Effect of low-level laser therapy irradiation and Bio-Oss graft material on the osteogenesis process in rabbit calvarium defects: a double blind experimental study.

    PubMed

    Rasouli Ghahroudi, Amir Alireza; Rokn, Amir Reza; Kalhori, Katayoun A M; Khorsand, Afshin; Pournabi, Alireza; Pinheiro, A L B; Fekrazad, Reza

    2014-05-01

    This study aims to assess the effect of low-level laser therapy (LLLT) irradiation and Bio-Oss graft material on the osteogenesis process in the rabbit calvarium defects. Twelve white male New Zealand rabbits were included in this study. Four 8-mm diameter identical defects were prepared on each rabbit's calvarium. One site was left as an untreated control (C), the second site was filled with Bio-Oss (B), the third site was treated with laser irradiation (L), and the fourth site treated with Bio-Oss and laser irradiation (B + L). In the laser group, a diode laser (wavelength 810 nm, output power 300 mW, irradiation mode CW, energy density 4 J/cm2) was applied immediately after surgery and then one other day for the next 20 days. After 4 and 8 weeks, the animals were sacrificed and histological and histomorphometric examinations were performed and the data were subjected to Friedman and repeated measurements ANOVA tests. Significant differences were not found regarding inflammation severity, foreign body reactions, and vitality of newly formed bone on 4th and 8th week after operation. The mean amount of new bone was 15.83 and 18.5% in the controls on the 4th and 8th week; 27.66 and 25.16% in the laser-irradiated group; 35.0 and 41.83% in Bio-Oss and 41.83 and 47.0% in the laser + Bio-Oss treated specimens with significant statistical differences (p <0.05). Application of LLLT in combination with Bio-Oss® can promote bone healing. Therefore, LLLT may be clinically beneficial in promoting bone formation in skeletal defects.

  6. Prevention of pure red cell aplasia after major or bidirectional ABO blood group incompatible hematopoietic stem cell transplantation by pretransplant reduction of host anti-donor isoagglutinins

    PubMed Central

    Stussi, Georg; Halter, Jörg; Bucheli, Eveline; Valli, Piero V.; Seebach, Lutz; Gmür, Jürg; Gratwohl, Alois; Schanz, Urs; Passweg, Jakob R.; Seebach, Jörg D.

    2009-01-01

    Background Persistent anti-donor isoagglutinins after major ABO blood group incompatible hematopoietic stem cell transplantation may cause delayed red blood cell engraftment and post-transplant pure red cell aplasia. Design and Methods We investigated the effect of pretransplant anti-donor isoagglutinin reduction by in vivo absorption and/or plasmapheresis on the incidence of pure red cell aplasia and the time to red blood cell engraftment in 153 hematopoietic stem cell transplant recipients with major ABO incompatibility. Results Twelve patients (8%) developed pure red cell aplasia, 3/98 (3%) with, and 9/55 (16%) without prior isoagglutinin reduction (p=0.009). Red blood cell engraftment was faster in patients with isoagglutinin reduction; in addition, peripheral blood hematopoietic stem cell transplantation, acute graft-versus-host disease, and younger age were associated with faster red blood cell engraftment in Cox regression analysis. In patients with pure red cell aplasia the mean red blood cell engraftment occurred after 225 days (p<0.001) and was associated with a simultaneous decrease of anti-donor isoagglutinins. Patients with pure red cell aplasia had higher pretransplant anti-donor isoagglutinin titers (p=0.001) and received more post-transplant red blood cell transfusions (p<0.001). Conclusions Following major ABO incompatible hematopoietic stem cell transplantation, pure red cell aplasia and delayed red blood cell engraftment depend on the levels of anti-donor isoagglutinins and are efficiently prevented by the pretransplant removal of these isoagglutinins. The benefits of reducing the time of transfusion-dependency and transfusion-associated risks must be carefully balanced against the potential side effects of isoagglutinin reduction. PMID:19144657

  7. Reconstruction of the proximal humerus by combined use of extracorporeally-irradiated osteochondral graft and free vascularized fibula following resection of Ewing sarcoma.

    PubMed

    Muramatsu, Keiichi; Fukano, Reiji; Ihara, Koichiro; Iwanaga, Ryuta; Taguchi, Toshihiko

    2010-12-01

    Reconstruction of the proximal humerus following limb-saving resection of malignant bone tumor is extremely challenging. We describe here a novel anatomical reconstruction technique in a young patient. A 6-year-old girl with Ewing sarcoma of the proximal humerus was treated by wide excision of the tumor followed by reconstruction with extracorporeally-irradiated osteoarticular autograft combined with an intramedullary inserted free vascularized fibula graft. Proper alignment of the shoulder joint was maintained with no osteoarthritic changes after 16 months. The resulting limb function was satisfactory. This biological reconstruction method was safe and without serious complication. It is indicated for the reconstruction of non-weight-bearing joints and is ideal for the proximal humerus.

  8. Effect of pre-irradiation PPO-grafted maleic anhydride on structure and properties of PPO-g-MAH/PA66 blends

    NASA Astrophysics Data System (ADS)

    Li, Wenfei; Yao, Zhanhai; Yao, Ruixiang; Li, Xuan; Liu, Shumei

    2014-04-01

    The pre-irradiation polyphenylene oxide (PPO)-graft-maleic anhydride (PPO-g-MAH) was carried out by reactive extrusion. The chemical structure of PPO-g-MAH was characterized by means of Fourier-transform infrared spectroscopy. The wettability of PPO-g-MAH was characterized by the contact angle method. The blends of PPO-g-MAH/polyamide 66 (PA66) were prepared. Compared with the PPO/PA66 blends, mechanical properties of PPO-g-MAH/PA66 blends were distinctly improved. Smaller dispersed particle sizes with narrower distribution were found in PPO-g-MAH/PA66 blends, via field-emitted scanning electron microscopy. Rheological properties of PPO-g-MAH/PA66 blends were studied with a rotational rheometer.

  9. Pre-transplant low level HLA antibody shows a composite poor outcome in long-term outcome of renal transplant recipients.

    PubMed

    Tian, Jun; Li, Dadong; Alberghini, Tod V; Rewinski, Michael; Guo, Ning; Bow, Laurine M

    2015-03-01

    To determine the significance of low-level DSA (donor specific antibody) in patients transplanted with negative cytotoxicity AHG (antihuman immunoglobulin) crossmatch, data from 279 patients who received a kidney transplant between July 1999 and March 2006 were collected. All kidney recipients received ABO-compatible donors. A poor outcome was defined as any one of the following: death, Cr>2.0 mmol/L, occurrence of a rejection episode. Luminex Screening and Single Antigen assays from Tepnel Life Codes were used to detect human leukocyte antigen antibodies on pre-transplant sera retrospectively. Twenty-four out of 279 recipients demonstrated the presence of solid-phase DSA (MFI>1000) present pre-transplant. In DSA+ group, the accumulated good versus poor outcome rate was 0.30 versus 0.70, respectively. These rates were 0.49 and 0.51, respectively, in the DSA- group. The difference in composite poor outcome between DSA+ versus DSA- group was significant (p=0.030). The DSA- group had no difference in patient survival as compared to the DSA+ group (p=0.061). There is no statistically significant difference for either mortality or outcome results between high MFI (>2000) and low MFI (≤2000) groups. Our data suggest that solid-phase antibodies which are not strong enough to elicit a positive T-AHG crossmatch may influence long-term graft outcome.

  10. [Effect of pre-transplant donor specific antibody on antibody-mediated rejection and graft dysfunction].

    PubMed

    Wang, Ning; Li, Wei; Zhang, Sheng

    2016-05-01

    目的:研究肾移植受者的术前供者特异性抗体(donor specific antibody,DSA)与其术后发生抗体介导的体液排斥反应(antibody-mediated rejection,AMR)及移植肾功能的关系。方法:选取符合要求的肾移植受者88例。术前采用Luminex流式法对肾移植受者进行DSA检测,并将受者分为DSA阳性组(n=20)与DSA阴性组(n=68)。随访时间为2年。术后参照Banff 2005标准对移植肾病理形态进行评估分级,并观察移植肾的情况。结果: DSA阳性组与阴性组AMR发生率分别为20.0%和1.5%,移植物丢失发生率分别为15.0%和1.5%,两组比较差异均有统计学意义(分别P<0.01,P<0.05);AMR受者最高DSA的荧光指数中值(mean fluorescence intensity,MFI)较非AMR受者差异明显(P<0.01);受试者工作特征(receiver operating characteristic,ROC)曲线显示肾移植术后受者发展为AMR的最高MFI阈值为7909.5。两组移植肾功能延迟回复的发生相比较,差异无统计学意义(P>0.05)。结论:肾移植术前检测DSA水平,可以预测AMR的发生风险和移植肾功能状态。最高DSA值的MFI截点(7909.5)能够预测AMR发生的风险。.

  11. Beneficial Effect of Short Pretransplant Period of Hypothermic Pulsatile Perfusion of the Warm-Ischemic Kidney after Cold Storage: Experimental Study.

    PubMed

    Lázaro, Alberto; Humanes, Blanca; Jado, Juan Carlos; Mojena, Marina; González-Nicolás, María Ángeles; Del Cañizo, Juan Francisco; Tejedor, Alberto; Lledó-García, Enrique

    2016-01-01

    Warm ischemia (WI) produces a significant deleterious effect in potential kidney grafts. Hypothermic machine perfusion (HMP) seems to improve immediate graft function after transplant. Our aim was to analyze the effect of short pretransplant periods of pulsatile HMP on histology and renal injury in warm-ischemic kidneys. Twelve minipigs were used. WI was achieved in the right kidney by applying a vascular clamp for 45 min. After nephrectomy, autotransplant was performed following one of two strategies: cold storage of the kidneys or cold storage combined with perfusion in pulsatile HMP. The graft was removed early to study renal morphology, inflammation (fibrosis), and apoptosis. Proinflammatory activity and fibrosis were less pronounced after cold storage of the kidneys with HMP than after cold storage only. The use of HMP also decreased apoptosis compared with cold storage only. The detrimental effects on cells of an initial and prolonged period of WI seem to improve with a preservation protocol that includes a short period of pulsatile HMP after cold storage and immediately before the transplant, in comparison with cold storage only.

  12. Beneficial Effect of Short Pretransplant Period of Hypothermic Pulsatile Perfusion of the Warm-Ischemic Kidney after Cold Storage: Experimental Study

    PubMed Central

    Humanes, Blanca; Jado, Juan Carlos; Mojena, Marina; González-Nicolás, María Ángeles; del Cañizo, Juan Francisco; Lledó-García, Enrique

    2016-01-01

    Warm ischemia (WI) produces a significant deleterious effect in potential kidney grafts. Hypothermic machine perfusion (HMP) seems to improve immediate graft function after transplant. Our aim was to analyze the effect of short pretransplant periods of pulsatile HMP on histology and renal injury in warm-ischemic kidneys. Twelve minipigs were used. WI was achieved in the right kidney by applying a vascular clamp for 45 min. After nephrectomy, autotransplant was performed following one of two strategies: cold storage of the kidneys or cold storage combined with perfusion in pulsatile HMP. The graft was removed early to study renal morphology, inflammation (fibrosis), and apoptosis. Proinflammatory activity and fibrosis were less pronounced after cold storage of the kidneys with HMP than after cold storage only. The use of HMP also decreased apoptosis compared with cold storage only. The detrimental effects on cells of an initial and prolonged period of WI seem to improve with a preservation protocol that includes a short period of pulsatile HMP after cold storage and immediately before the transplant, in comparison with cold storage only. PMID:27556029

  13. Subclinical pulmonary function defects following autologous and allogeneic bone marrow transplantation: relationship to total body irradiation and graft-versus-host disease

    SciTech Connect

    Tait, R.C.; Burnett, A.K.; Robertson, A.G.; McNee, S.; Riyami, B.M.; Carter, R.; Stevenson, R.D. )

    1991-06-01

    Pulmonary function results pre- and post-transplant, to a maximum of 4 years, were analyzed in 98 patients with haematological disorders undergoing allogeneic (N = 53) or autologous bone marrow transplantation (N = 45) between 1982 and 1988. All received similar total body irradiation based regimens ranging from 9.5 Gy as a single fraction to 14.4 Gy fractionated. FEV1/FVC as a measure of airway obstruction showed little deterioration except in patients experiencing graft-versus-host disease in whom statistically significant obstructive ventilatory defects were evident by 6 months post-transplant (p less than 0.01). These defects appeared to be permanent. Restrictive ventilatory defects, as measured by reduction in TLC, and defects in diffusing capacity (DLCO and KCO) were also maximal at 6 months post-transplant (p less than 0.01). Both were related, at least in part, to the presence of GVHD (p less than 0.01) or use of single fraction TBI with absorbed lung dose of 8.0 Gy (p less than 0.05). Fractionated TBI resulted in less marked restricted ventilation and impaired gas exchange, which reverted to normal by 2 years, even when the lung dose was increased from 11.0 Gy to between 12.0 and 13.5 Gy. After exclusion of patients with GVHD (30% allografts) there was no significant difference in pulmonary function abnormalities between autograft and allograft recipients.

  14. Treatment of aggressive multiple myeloma by high-dose chemotherapy and total body irradiation followed by blood stem cells autologous graft

    SciTech Connect

    Fermand, J.P.; Levy, Y.; Gerota, J.; Benbunan, M.; Cosset, J.M.; Castaigne, S.; Seligmann, M.; Brouet, J.C.

    1989-01-01

    Eight patients with stage III aggressive multiple myeloma, refractory to current chemotherapy in six cases, were treated by high-dose chemotherapy (nitrosourea, etoposide, and melphalan) (HDC) and total body irradiation (TBI), followed by autografting with blood stem cells. These cells were previously collected by leukapheresis performed during hematologic recovery following cytotoxic drug-induced bone marrow aplasia. Seven patients were alive 9 to 17 months after HDC-TBI and graft. One died at day 40 from cerebral bleeding. All living patients achieved a 90% or greater reduction in tumor mass. In two cases, a complete remission (CR) has persisted at a follow-up of 15 and 16 months. Three patients have been well and off therapy with stable minimal residual disease (RD) since 10, 11, and 17 months, respectively. A patient in apparent CR and another with RD have relapsed 9 to 12 months posttreatment. Autologous blood-derived hematopoietic stem cells induced successful and sustained engraftment in all living patients. These results, although still preliminary, indicate that HDC and TBI, followed by blood stem cells autograft, which has both practical and theoretical interest over allogeneic or autologous bone marrow transplantation, deserve consideration in selected patients with multiple myeloma.

  15. Treatment of cutaneous and/or soft tissue manifestations of corticosteroids refractory chronic graft versus host disease (cGVHD) by a total nodal irradiation (TNI).

    PubMed

    Peyraga, Guillaume; Lizee, Thibaut; Gustin, Pierre; Clement-Colmou, Karen; Di Bartolo, Christelle; Supiot, Stephane; Mahe, Marc-Andre; François, Sylvie; Mege, Martine

    2017-02-09

    The management of corticosteroids refractory chronic graft versus host disease (cGVHD) remains controversial. Retrospective analysis of patients treated at the Integrated Center of Oncology by total nodal irradiation (TNI) was performed to evaluate its therapy potency. TNI delivers a dose of 1 Gy in a single session. The delimitation of the fields is clinical (upper limit: external auditory meatus; lower limit: mid-femur). No pre-therapeutic dosimetry scanner was necessary. Evaluation of the efficacy was by clinical measures at 6 months after the treatment. Twelve patients were treated by TNI between January 2010 and December 2013. TNI was used in second-line treatment or beyond. The median time between allograft and TNI was 31.2 months, and the median time between the first manifestations of cGVHD and TNI was about 24.2 months. Of the 12 patients, nine had a clinical response at 6 months (75%), including five complete clinical responses (41.6%). Five patients could benefit from a reduction of corticosteroid doses. Three patients had hematologic toxicity. TNI could be considered as an option for the treatment of a cutaneous and/or soft tissues corticosteroids refractory cGVHD. However, prospective randomized and double-blind trials remain essential to answer the questions about TNI safety and effectiveness.

  16. Total lymphoid irradiation in kidney and liver transplantation in the baboon: prolonged graft survival and alterations in T cell subsets with low cumulative dose regimens

    SciTech Connect

    Myburgh, J.A.; Smith, J.A.; Stark, J.H.; Browde, S.

    1984-02-01

    Prolonged kidney and liver allograft survival was produced in baboons by low cumulative doses (500 to 1200 rad) of total lymphoid irradiation (TLI). Continuing normal graft function for more than 1 year after transplantation was seen in 10 animals in this series. The longest survivor (> 4 years) rejected a third party kidney allograft in typically acute fashion 1 yr after the original transplantation. The dose-response effect was parabolic, with a cumulative dose of 800 rad given as twice weekly fractions of 100 rad each being the most effective. With smaller cumulative doses (500 or 600 rad) results were improved if TLI was administered as a large number of smaller fractions. These regimens are free of the radiation related mortality observed in earlier studies with larger cumulative doses. Alterations in T cell subpopulations were studied in these baboons with the use of the anti-human monoclonal antibodies OKT11 (anti-total T cells), OKT4 (anti-T helper cells; Th), and OKT8 (anti-T suppressor/cytotoxic cells, Tsc), which cross-react with baboon lymphocytes. After completion of TLI but before transplantation, the relative percentage of Tsc cells fell and the percentage of Th and the Th/Tsc ratio rose. Transplantation was followed by an inversion of this ratio due to reciprocal changes in the percentages of Th and Tsc cells. This pattern persisted and increased until 6 mo after transplantation, when it reverted to that seen in untreated control animals.

  17. Longitudinal trajectory of sexual functioning after hematopoietic cell transplantation: impact of chronic graft-versus-host disease and total body irradiation.

    PubMed

    Wong, F Lennie; Francisco, Liton; Togawa, Kayo; Kim, Heeyoung; Bosworth, Alysia; Atencio, Liezl; Hanby, Cara; Grant, Marcia; Kandeel, Fouad; Forman, Stephen J; Bhatia, Smita

    2013-12-05

    This prospective study described the trajectory of sexual well-being from before hematopoietic cell transplantation (HCT) to 3 years after in 131 allogeneic and 146 autologous HCT recipients using Derogatis Interview for Sexual Function and Derogatis Global Sexual Satisfaction Index. Sixty-one percent of men and 37% of women were sexually active pre-HCT; the prevalence declined to 51% (P = .01) in men and increased to 48% (P = .02) in women at 3 years post-HCT. After HCT, sexual satisfaction declined in both sexes (P < .001). All sexual function domains were worse in women compared with men (P ≤ .001). Orgasm (P = .002) and drive/relationship (P < .001) declined in men, but sexual cognition/fantasy (P = .01) and sexual behavior/experience (P = .01) improved in women. Older age negatively impacted sexual function post-HCT in both sexes (P < .01). Chronic graft-versus-host disease was associated with lower sexual cognition/fantasy (P = .003) and orgasm (P = .006) in men and sexual arousal (P = .05) and sexual satisfaction (P = .005) in women. All male sexual function domains declined after total body irradiation (P < .05). This study identifies vulnerable subpopulations that could benefit from interventional strategies to improve sexual well-being.

  18. Bone graft

    MedlinePlus

    Autograft - bone; Allograft - bone; Fracture - bone graft; Surgery - bone graft; Autologous bone graft ... Fuse joints to prevent movement Repair broken bones (fractures) that have bone loss Repair injured bone that ...

  19. Radiation grafting on natural films

    NASA Astrophysics Data System (ADS)

    Lacroix, M.; Khan, R.; Senna, M.; Sharmin, N.; Salmieri, S.; Safrany, A.

    2014-01-01

    Different methods of polymer grafting using gamma irradiation are reported in the present study for the preparation of newly functionalized biodegradable films, and some important properties related to their mechanical and barrier properties are described. Biodegradable films composed of zein and poly(vinyl alcohol) (PVA) were gamma-irradiated in presence of different ratios of acrylic acid (AAc) monomer for compatibilization purpose. Resulting grafted films (zein/PVA-g-AAc) had their puncture strength (PS=37-40 N mm-1) and puncture deformation (PD=6.5-9.8 mm) improved for 30% and 50% PVA in blend, with 5% AAc under 20 kGy. Methylcellulose (MC)-based films were irradiated in the presence of 2-hydroxyethyl methacrylate (HEMA) or silane, in order to determine the effect of monomer grafting on the mechanical properties of films. It was found that grafted films (MC-g-HEMA and MC-g-silane) using 35% monomer performed higher mechanical properties with PS values of 282-296 N mm-1 and PD of 5.0-5.5 mm under 10 kGy. Compatibilized polycaprolactone (PCL)/chitosan composites were developed via grafting silane in chitosan films. Resulting trilayer grafted composite film (PCL/chitosan-g-silane/PCL) presented superior tensile strength (TS=22 MPa) via possible improvement of interfacial adhesion (PCL/chitosan) when using 25% silane under 10 kGy. Finally, MC-based films containing crystalline nanocellulose (CNC) as a filling agent were prepared and irradiated in presence of trimethylolpropane trimethacrylate (TMPTMA) as a grafted plasticizer. Grafted films (MC-g-TMPTMA) presented superior mechanical properties with a TS of 47.9 MPa and a tensile modulus (TM) of 1792 MPa, possibly due to high yield formation of radicals to promote TMPTMA grafting during irradiation. The addition of CNC led to an additional improvement of the barrier properties, with a significant 25% reduction of water vapor permeability (WVP) of grafted films.

  20. Effects of LED or laser phototherapy on bone defects grafted with MTA and irradiated with laser or LED light: a comparative Raman spectroscopic study

    NASA Astrophysics Data System (ADS)

    Pinheiro, Antonio L. B.; Soares, Luiz G. P.; Barbosa, Artur Felipe S.; Silveira, Landulfo, Jr.

    2012-03-01

    We studied peaks of calcium hydroxyapatite - CHA on defects grafted with MTA, treated or not with Light Emitting Diode - LED or IR Laser. 54 rats were divided in 6 groups each subdivided into 3 subgroups (15,21,30d). LED (λ850 +/- 10nm) or IR Laser (λ850 nm) was applied over (LED) or in 4 points around the defect at 48 h intervals for 15 days. Raman readings were taken at the surface of the defect. The smaller overall intensity of the peak was found in Group MTA + Laser (1510.2 +/- 274.1) and the highest on Group LED (2322 +/- 715). There were no statistically significant differences between non-irradiated subjects on regards the CHA peaks. On the other hand, there were statistically significant differences between the Group Clot and LED, Clot and Laser, and Clot and MTA + Laser (p =0.01, p = 0.02, p = 0.003). There were no significant differences between Group MTA and MTA + LED (p=0.2) but significant differences were seen between Groups MTA and MTA + Laser (p=0.01). Significant differences were also observed between Groups LED and Laser (p <0.001) and between Groups MTA + LED and MTA + Laser (p=0.009). MTA, due to its characteristics, seemed to be directly affected by the light. However, the use of either phototherapy positively affected bone healing similarly as observed on different studies using other biomaterials. The overall analysis of our results indicated that the use of either light source resulted in a better, more advanced, and of quality bone repair.

  1. Radiation resistivity of polyacenaphthylene-grafted polyethylene

    NASA Astrophysics Data System (ADS)

    Hayakawa, Kiyoshi; Kawase, Kaoru; Yamakita, Hiromi

    Thin poly (ethylene-g-acenaphthylene) films prepared by the vapor-phase grafting method were subjected to the γ-irradiation in air, and various changes in tensile and structural properties of the film were investigated by comparing with those of the untreated or crosslinked polyethylene film. Polyethylene got to lose its inherent necking property by oxidative degradation and to be brittle-fractured by the irradiation dose less than 100 Mrad in air. The polyacenaphthylene-grafted polyethylenes (extent of grafting, ˜ 54 by {100( P-P°) }/{P°}), however, kept their ductility up to 200 Mrad or more, and the rate of increase in elastic modulus as well as yield strength with the increasing irradiation dose was considerably lower than that of untreated or crosslinked polyethylene. The effect of the grafting extent, and that of the irradiation dose-rate on the fracture energy were also examined. The weight increase of polyethylene due to the oxygen consumption and the resulting formation of carbonyl group which proceeded proportionally with the irradiation dose were remarkably suppressed by the grafting, whereas the double bond formation seemed to be unaffected by it. The grafted film held the original content of gel fraction unchanged during the irradiation in air, but the average molecular weight of the sol fraction decreased gradually. Meanwhile, the gel fraction of the crosslinked polyethylene was degenerated by a small dose of irradiation. The analysis of gaseous products revealed the formation of water, methanol, acetaldehyde and so forth from the irradiated grafted film. The grafting procedure and the subsequent irradiation of the grafted film did not affect the degree of crystallinity of the backbone polyethylene. The role played by the grafted polyacenaphthylene for endowing the radiation resistivity to polyethylene and its inherent limitation in effect were discussed from the structural point of view of the grafted film.

  2. Properties of starch-polyglutamic acid (PGA) graft copolymer prepared by microwave irradiation - Fourier transform infrared spectroscopy (FTIR) and rheology studies

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The rheological properties of waxy starch-'-polygutamic acid (PGA) graft copolymers were investigated. Grafting was confirmed by FTIR spectroscopy. The starch-PGA copolymers absorbed water and formed gels, which exhibited concentration-dependent viscoelastic solid properties. Higher starch-PGA conce...

  3. Impact of pretransplant therapy and depth of disease response before autologous transplantation for multiple myeloma.

    PubMed

    Vij, Ravi; Kumar, Shaji; Zhang, Mei-Jie; Zhong, Xiaobo; Huang, Jiaxing; Dispenzieri, Angela; Abidi, Muneer H; Bird, Jennifer M; Freytes, César O; Gale, Robert Peter; Kindwall-Keller, Tamila L; Kyle, Robert A; Landsburg, Daniel J; Lazarus, Hillard M; Munker, Reinhold; Roy, Vivek; Sharma, Manish; Vogl, Dan T; Wirk, Baldeep; Hari, Parameswaran N

    2015-02-01

    Patients with multiple myeloma (MM) who are eligible for autologous stem cell transplantation (ASCT) typically receive a finite period of initial therapy before ASCT. It is not clear if patients with suboptimal (less than a partial) response to initial therapy benefit from additional alternative therapy with intent to maximize pretransplant response. We identified 539 patients with MM who had an ASCT after having achieved less than a partial response (PR) to first-line induction chemotherapy between 1995 and 2010. These patients were then divided into 2 groups: those who received additional salvage chemotherapy before ASCT (n = 324) and those who had no additional salvage chemotherapy immediately before ASCT (n = 215). Additional pretransplant chemotherapy resulted in deepening responses in 68% (complete response in 8% and PR in 60%). On multivariate analysis there was no impact of pretransplant salvage chemotherapy on treatment-related mortality, risk for relapse, progression-free survival, or overall survival. In conclusion, for patients achieving less than a PR to initial induction therapy, including with novel agent combinations, additional pre-ASCT salvage chemotherapy improved the depth of response and pre-ASCT disease status but was not associated with survival benefit.

  4. Obesity is an independent risk factor for pre-transplant portal vein thrombosis in liver recipients

    PubMed Central

    2012-01-01

    Background Portal vein thrombosis is a frequent complication in end-stage cirrhosis with a considerable peri-operative risk for liver transplant candidates. We aimed to characterize the pre-transplant portal vein thrombosis in a cohort of liver transplant recipients, and to identify independent risk factors for this complication. Methods 380 consecutive primary orthotopic liver transplants were performed in the Digestive Surgery Department of “12 de Octubre” Hospital (Madrid, Spain), between January 2001 and December 2006. The main risk factors considered were smoking, obesity, metabolic disorders, previous immobility, surgery or trauma, nephrotic syndrome, associated tumor, inflammatory disease, neoplasm myeloprolipherative. Furthermore we have reported genetic thrombophilia results for 271 recipients. Results Sixty-two (16.3%) patients developed pre-transplant portal vein thrombosis and its presence had no impact in the overall survival of liver recipients. Obesity was the only independent risk factor for pre-transplant portal vein thrombosis. Conclusion We recommend close control of cardiovascular factors in patients with liver cirrhosis in order to avoid associated thrombosis. PMID:22909075

  5. The ability of pretransplant test-dose pharmacokinetic profiles to reduce early adverse events after renal transplantation.

    PubMed

    Kahan, B D; Welsh, M; Rutzky, L; Lewis, R; Knight, R; Katz, S; Napoli, K; Grevel, J; Van Buren, C T

    1992-02-01

    Pretransplant test-dose pharmacokinetic profiles were used to determine individual cyclosporine drug bioavailability and clearance rates in renal transplant patients. Assuming a linear relation between dose and area under the concentration curve (AUC), starting i.v. and p.o. CsA doses were computed from the test-dose results. Target values were 400 ng/ml steady-state concentration (Css) during continuous intravenous infusion, and 500 ng/ml average drug concentration (Cavss = AUC/dosing interval) after oral administration, based upon measurements with the specific monoclonal antibody 3H-tracer radioimmunoassay. The outcomes after dose individualization with a 1-(n = 32), 2-(n = 38), or 3-(n = 41) hr i.v. infusion test dose and a p.o. test dose (n = 111) were compared with 228 historical control patients who received a uniform protocol of CsA i.v. at 2.5 mg/kg/day and p.o. at 14 mg/kg/day. The observed Css after i.v. CsA was within 10% of the target concentration in 73% of recipients tested with the 3-hr protocol, a significantly greater fraction than achieved with either the uniform dose (14%), or the 1-(34%) and 2-(25%) hr protocols. Patients in the 3-hr protocol group showed reduced incidences of delayed graft function, early graft loss, and rejection episodes, and a lower mean serum creatinine value, particularly at 7 but also at 30 days posttransplantation. Administration of the predicted oral dose produced a peak concentration of greater than or equal to 700 ng/ml drug absorption in 60% of recipients at 3 days, 90% at 5 days, and 98% at 7 days. The test-dose method less effectively predicted the appropriate oral CsA dose to produce target Cssav and failed to reduce the 90-day rejection incidence. Despite its limitations with the more-complicated p.o. route, the test-dose method successfully predicts i.v. CsA doses, thereby reducing the incidence of early adverse events.

  6. Possibility of Solid-State Graft Copolymerization on Poly(ethylene terephthalate) Films by Plasma Irradiation and Effects of Surface Modification

    NASA Astrophysics Data System (ADS)

    Narushima, Kazuo; Matsuda, Noriko; Mizutani, Chie; Yamashita, Nanami; Inagaki, Norihiro; Iio, Kokoro; Isono, Yoshihiro; Islam, Mohammed Rafiqul

    2007-07-01

    A solid-state graft copolymerization for poly(ethylene terephthalate) (PET) films was proposed for a new surface modification technique. The functional groups included in graft monomers can be introduced on a PET surface. Allylbiguanide hydrochloric acid salt (ABG), N-methylol acrylamide (NM-AAm), and N-isopropyl acrylamide (NIP-AAm) were used as graft monomers. This technique led to a large change in the N/C atomic ratio on the PET film surfaces, which shows that nitrogen functional groups were introduced on PET surfaces. On the grafted PET films, a new N 1s spectrum appeared. This N 1s spectrum contained two components, namely, amino and amido groups, which suggests that the two groups were introduced onto the PET surfaces. In particular, isopropyl groups were introduced on the PET surface in the case of NIP-AAm. The formation of these functional groups demonstrated changes in the surface properties of PET, such as improved wettability.

  7. Determinants of graft survival in pediatric and adolescent live donor kidney transplant recipients: a single center experience.

    PubMed

    El-Husseini, Amr A; Foda, Mohamed A; Shokeir, Ahmed A; Shehab El-Din, Ahmed B; Sobh, Mohamed A; Ghoneim, Mohamed A

    2005-12-01

    To study the independent determinants of graft survival among pediatric and adolescent live donor kidney transplant recipients. Between March 1976 and March 2004, 1600 live donor kidney transplants were carried out in our center. Of them 284 were 20 yr old or younger (mean age 13.1 yr, ranging from 5 to 20 yr). Evaluation of the possible variables that may affect graft survival were carried out using univariate and multivariate analyses. Studied factors included age, gender, relation between donor and recipient, original kidney disease, ABO blood group, pretransplant blood transfusion, human leukocyte antigen (HLA) matching, pretransplant dialysis, height standard deviation score (SDS), pretransplant hypertension, cold ischemia time, number of renal arteries, ureteral anastomosis, time to diuresis, time of transplantation, occurrence of acute tubular necrosis (ATN), primary and secondary immunosuppression, total dose of steroids in the first 3 months, development of acute rejection and post-transplant hypertension. Using univariate analysis, the significant predictors for graft survival were HLA matching, type of primary urinary recontinuity, time to diuresis, ATN, acute rejection and post-transplant hypertension. The multivariate analysis restricted the significance to acute rejection and post-transplant hypertension. The independent determinants of graft survival in live-donor pediatric and adolescent renal transplant recipients are acute rejection and post-transplant hypertension.

  8. Pretransplant NPM1 MRD levels predict outcome after allogeneic hematopoietic stem cell transplantation in patients with acute myeloid leukemia.

    PubMed

    Kayser, S; Benner, A; Thiede, C; Martens, U; Huber, J; Stadtherr, P; Janssen, J W G; Röllig, C; Uppenkamp, M J; Bochtler, T; Hegenbart, U; Ehninger, G; Ho, A D; Dreger, P; Krämer, A

    2016-07-29

    The objective was to evaluate the prognostic impact of pre-transplant minimal residual disease (MRD) as determined by real-time quantitative polymerase chain reaction in 67 adult NPM1-mutated acute myeloid leukemia patients receiving allogeneic hematopoietic stem cell transplantation (HSCT). Twenty-eight of the 67 patients had a FLT3-ITD (42%). Median age at transplantation was 54.7 years, median follow-up for survival from time of allografting was 4.9 years. At transplantation, 31 patients were in first, 20 in second complete remission (CR) and 16 had refractory disease (RD). Pre-transplant NPM1 MRD levels were measured in 39 CR patients. Overall survival (OS) for patients transplanted in CR was significantly longer as compared to patients with RD (P=0.004), irrespective of whether the patients were transplanted in first or second CR (P=0.74). There was a highly significant difference in OS after allogeneic HSCT between pre-transplant MRD-positive and MRD-negative patients (estimated 5-year OS rates of 40 vs 89%; P=0.007). Multivariable analyses on time to relapse and OS revealed pre-transplant NPM1 MRD levels >1% as an independent prognostic factor for poor survival after allogeneic HSCT, whereas FLT3-ITD had no impact. Notably, outcome of patients with pre-transplant NPM1 MRD positivity >1% was as poor as that of patients transplanted with RD.

  9. Reconstruction of Irradiated Mandible after Segmental Resection of Osteoradionecrosis—A Technique Employing a Microvascular Latissimus Dorsi Flap and Subsequent Particulate Iliac Bone Grafting

    PubMed Central

    Hillerup, Soren; Elberg, Jens Jorgen; Thorn, Jens Jorgen; Andersen, Mikael

    2014-01-01

    The fibula osteocutaneous flap has revolutionized the options of mandibular segmental defect bridging in osteoradionecrosis (ORN). In selected cases, however, the fibula flap is not an option because of atherosclerosis or other features that compromise the vascularity of the lower leg and foot. The aim of this study is to present an alternative method of mandibular segmental reconstruction employing a latissimus dorsi (LD) flap and subsequent particulate iliac free bone graft reconstruction. In 15 patients with ORN, a mandibular segmental defect was bridged with a reconstruction plate, and the defect site was primed with a LD musculocutaneous flap wrapped around the reconstruction plate to bring in vascularized tissue and optimize healing conditions for a subsequent particulate iliac free bone graft reconstruction. The management of defect closure was successful in all 15 patients. Twelve patients had a subsequent bone grafting from the posterior ileum for repair of defects up to 14 cm length. Three patients had no bone graft for various reasons. In three patients dental rehabilitation was achieved with implant supported prosthodontic appliances. Ten patients met the success criteria of uneventful graft healing with restitution of osseous continuity, mandibular height, symmetry and function, and avoidance of reconstruction plate fracture. PMID:25136407

  10. Pre-transplant thymic function is associated with the risk of cytomegalovirus disease after solid organ transplantation.

    PubMed

    Gracia-Ahufinger, I; Ferrando-Martínez, S; Montejo, M; Muñoz-Villanueva, M C; Cantisán, S; Rivero, A; Solana, R; Leal, M; Torre-Cisneros, J

    2015-05-01

    Cytomegalovirus (CMV) disease is an important complication in solid organ transplant recipients. Thymic function in adults is associated with specific T-cell immunity. Pre-transplant thymic function was analysed in 75 solid organ transplant patients by the use of nested PCR. The primary outcome was the incidence of CMV disease 12 months after transplantation. Using multivariable logistic regression, we studied whether pre-transplant thymic function is an independent risk factor for CMV disease after transplantation. Thymic function was related to the risk of CMV disease in CMV-seropositive recipients. In these recipients, pre-transplant thymic function of <9.5 (OR 11.27, 95% CI 1.11-114.43, p 0.040) and the use of thymoglobulin (OR 8.21, 95% CI 1.09-61.84, p 0.041) were independent risk factors for CMV disease at 12 months after transplantation. Patients with pre-transplant thymic function values of <9.5 had a higher subsequent incidence of CMV disease (24%) than patients with values of ≥ 9.5 (3%) (log-rank test: 5.727; p 0.017). The positive and negative predictive values of these pre-transplant thymic function cut-offs were 0.24 (95% CI 0.10-0.45) and 0.97 (95% CI 0.82-1.00), respectively. Pre-transplant thymic function in CMV-seropositive candidates could be useful in determining the risk of post-transplant CMV disease in solid organ transplant patients, selecting a group of low-risk candidates.

  11. Radiation-induced grafting of diallyldimethylammonium chloride onto acrylic acid grafted polyethylene

    NASA Astrophysics Data System (ADS)

    Francis, Sanju; Dhanawade, B. R.; Mitra, D.; Varshney, Lalit; Sabharwal, Sunil

    2009-01-01

    Diallyldimethylammonium chloride (DADMAC) was grafted onto polyethylene (PE) films by a double grafting procedure. The PE film was initially modified by grafting acrylic acid (AA), through a mutual irradiation method. AA-g-PE film, thus obtained was subjected to subsequent radiation grafting reaction of DADMAC, to give a DADMAC-g-AA-g-PE film having a comb-type structure. The influence of different conditions, such as the extent of AA grafting, DADMAC concentration, absorbed dose and dose rate, on the grafting yield of DADMAC was investigated. A maximum DADMAC grafting of 30% was achieved. The equilibrium degree of swelling (EDS) of the grafted films were gravimetrically determined. TGA and FT-IR techniques were employed to characterize the grafted PE films.

  12. Fludarabine with pharmacokinetically guided IV busulfan is superior to fixed-dose delivery in pretransplant conditioning of AML/MDS patients.

    PubMed

    Andersson, B S; Thall, P F; Valdez, B C; Milton, D R; Al-Atrash, G; Chen, J; Gulbis, A; Chu, D; Martinez, C; Parmar, S; Popat, U; Nieto, Y; Kebriaei, P; Alousi, A; de Lima, M; Rondon, G; Meng, Q H; Myers, A; Kawedia, J; Worth, L L; Fernandez-Vina, M; Madden, T; Shpall, E J; Jones, R B; Champlin, R E

    2017-04-01

    We hypothesized that IV busulfan (Bu) dosing could be safely intensified through pharmacokinetic (PK-) dose guidance to minimize the inter-patient variability in systemic exposure (SE) associated with body-sized dosing, and that this should improve outcome of AML/MDS patients undergoing allogeneic stem cell transplantation. To test this hypothesis, we treated 218 patients (median age 50.7 years, male/female 50/50%) with fludarabine 40 mg/m(2) once daily x4, each dose followed by IV Bu, randomized to 130 mg/m(2) (N=107) or PK-guided to average daily SE, AUC of 6000 μM min (N=111), stratified for remission status and allo-grafting from HLA-matched donors. Toxicity and GvHD rates in the groups were similar; the risk of relapse or treatment-related mortality remained higher in the fixed-dose group throughout the 80-month observation period. Further, PK-guidance yielded safer disease control, leading to improved overall and PFS, most prominently in MDS patients and in AML patients not in remission at allogeneic stem cell transplantation. We conclude that AML/MDS patients receiving pretransplant conditioning treatment with our 4-day regimen may benefit significantly from PK-guided Bu dosing. This could be considered an alternative to fixed-dose delivery since it provides the benefit of precise dose delivery to a predetermined SE without increasing risk(s) of serious toxicity and/or GvHD.

  13. Identification of Molecular Markers of Delayed Graft Function Based on the Regulation of Biological Ageing

    PubMed Central

    McGuinness, Dagmara; Leierer, Johannes; Shapter, Olivier; Mohammed, Suhaib; Gingell-Littlejohn, Marc; Kingsmore, David B.; Little, Ann-Margaret; Kerschbaum, Julia; Schneeberger, Stefan; Maglione, Manuel; Nadalin, Silvio; Wagner, Sylvia; Königsrainer, Alfred; Aitken, Emma; Whalen, Henry; Clancy, Marc; McConnachie, Alex; Koppelstaetter, Christian; Stevenson, Karen S.; Shiels, Paul G.

    2016-01-01

    Introduction Delayed graft function is a prevalent clinical problem in renal transplantation for which there is no objective system to predict occurrence in advance. It can result in a significant increase in the necessity for hospitalisation post-transplant and is a significant risk factor for other post-transplant complications. Methodology The importance of microRNAs (miRNAs), a specific subclass of small RNA, have been clearly demonstrated to influence many pathways in health and disease. To investigate the influence of miRNAs on renal allograft performance post-transplant, the expression of a panel of miRNAs in pre-transplant renal biopsies was measured using qPCR. Expression was then related to clinical parameters and outcomes in two independent renal transplant cohorts. Results Here we demonstrate, in two independent cohorts of pre-implantation human renal allograft biopsies, that a novel pre-transplant renal performance scoring system (GRPSS), can determine the occurrence of DGF with a high sensitivity (>90%) and specificity (>60%) for donor allografts pre-transplant, using just three senescence associated microRNAs combined with donor age and type of organ donation. Conclusion These results demonstrate a relationship between pre-transplant microRNA expression levels, cellular biological ageing pathways and clinical outcomes for renal transplantation. They provide for a simple, rapid quantitative molecular pre-transplant assay to determine post-transplant allograft function and scope for future intervention. Furthermore, these results demonstrate the involvement of senescence pathways in ischaemic injury during the organ transplantation process and an indication of accelerated bio-ageing as a consequence of both warm and cold ischaemia. PMID:26734715

  14. Long-Term Outcomes after Treatment with Clofarabine ± Fludarabine with Once-Daily Intravenous Busulfan as Pretransplant Conditioning Therapy for Advanced Myeloid Leukemia and Myelodysplastic Syndrome.

    PubMed

    Alatrash, Gheath; Thall, Peter F; Valdez, Benigno C; Fox, Patricia S; Ning, Jing; Garber, Haven R; Janbey, Selma; Worth, Laura L; Popat, Uday; Hosing, Chitra; Alousi, Amin M; Kebriaei, Partow; Shpall, Elizabeth J; Jones, Roy B; de Lima, Marcos; Rondon, Gabriela; Chen, Julianne; Champlin, Richard E; Andersson, Borje S

    2016-10-01

    Pretransplant conditioning regimens critically determine outcomes in the setting of allogeneic stem cell transplantation (allo-SCT). The use of nucleoside analogs such as fludarabine (Flu) in combination with i.v. busulfan (Bu) has been shown to be highly effective as a pretransplant conditioning regimen in acute myeloid leukemia (AML), chronic myeloid leukemia (CML), and myelodysplastic syndrome (MDS). Because leukemia relapse remains the leading cause of death after allo-SCT, we studied whether clofarabine (Clo), a nucleoside analog with potent antileukemia activity, can be used to complement Flu. In a preliminary report, we previously showed the safety and efficacy of Clo ± Flu with i.v. Bu in 51 patients with high-risk AML, CML, and MDS. The study has now been completed, and we present long-term follow-up data on the entire 70-patient population, which included 49 (70%), 8 (11%), and 13 (19%) patients with AML, MDS, and CML, respectively. Thirteen patients (19%) were in complete remission, and 41 patients (59%) received matched unrelated donor grafts. Engraftment was achieved in all patients. Sixty-three patients (90%) achieved complete remission. There were no deaths reported at day +30, and the 100-day nonrelapse mortality rate was 4% (n = 3). Thirty-one percent of patients (n = 22) developed grades II to IV acute graft-versus-host disease, and the median overall survival and progression-free survival times were 2.4 years and .9 years, respectively. Our results confirm the safety and overall and progression-free survival advantage of the arms with higher Clo doses and lower Flu doses, which was most prominent in the AML/MDS group.

  15. Pretransplant FDG-PET in aggressive non-Hodgkin lymphoma: systematic review and meta-analysis.

    PubMed

    Adams, Hugo J A; Kwee, Thomas C

    2017-04-01

    This study aimed to systematically review and meta-analyze the value of pretransplant FDG-PET in predicting outcome after autologous stem cell transplantation in aggressive non-Hodgkin lymphoma. MEDLINE was systematically searched; included studies were methodologically assessed and meta-analyzed, when possible. Overall methodological quality of included studies (n = 11) was poor, with moderate risk of bias in the domains of study participation (n = 7) and prognostic factor measurement (n = 7), and high risk of bias in the domains of outcome measurement (n = 10), and study confounding (n = 11). In all aggressive non-Hodgkin lymphomas, pooled sensitivity and specificity were 54.0% and 73.1% in predicting treatment failure, and 54.5% and 68.7% in predicting death. Because of interstudy heterogeneity, additional subgroup analyses were performed. In newly diagnosed aggressive non-Hodgkin lymphoma, pooled sensitivity and specificity were 20.0% and 70.0% in predicting treatment failure, and 8.3% % and 30.5% in predicting death. In refractory/relapsed aggressive non-Hodgkin lymphoma, pooled sensitivity and specificity were 68.1% and 72.1% in predicting treatment failure, and 77.3% and 69.6% in predicting death. At present, pretransplant FDG-PET cannot be recommended in aggressive non-Hodgkin lymphoma, because available studies suffer from major methodological flaws, and reported prognostic estimates are low (i.e., poor in newly diagnosed and moderate in refractory/relapsed aggressive non-Hodgkin lymphoma).

  16. Prognostic value of pretransplant FDG-PET in refractory/relapsed Hodgkin lymphoma treated with autologous stem cell transplantation: systematic review and meta-analysis.

    PubMed

    Adams, Hugo J A; Kwee, Thomas C

    2016-04-01

    This study aimed to systematically review the prognostic value of pretransplant (18)F-fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) in refractory/relapsed Hodgkin lymphoma treated with autologous stem cell transplantation (SCT). MEDLINE was systematically searched for appropriate studies. Included studies were methodologically appraised. Results of individual studies were meta-analyzed, if possible. Eleven studies, comprising a total of 745 refractory/relapsed Hodgkin lymphoma patients who underwent FDG-PET before autologous SCT, were included. The overall methodological quality of these studies was moderate. The proportion of pretransplant FDG-PET positive patients ranged between 25 and 65.2 %. Progression-free survival ranged between 0 and 52 % in pretransplant FDG-PET positive patients, and between 55 and 85 % in pretransplant FDG-PET negative patients. Overall survival ranged between 17 and 77 % in pretransplant FDG-PET positive patients, and between 78 and 100 % in FDG-PET negative patients. Based on five studies that provided sufficient data for meta-analysis, pooled sensitivity and specificity of pretransplant FDG-PET in predicting treatment failure (i.e., either progressive, residual, or relapsed disease) were 67.2 % (95 % confidence interval [CI] 58.2-75.3 %) and 70.7 % (95 % CI 64.2-76.5 %), respectively. Based on two studies that provided sufficient data for meta-analysis, pooled sensitivity and specificity of pretransplant FDG-PET in predicting death during follow-up were 74.4 % (95 % CI 58.8-86.5 %) and 58.0 % (95 % CI 49.3-66.3 %), respectively. In conclusion, the moderate quality evidence suggests pretransplant FDG-PET to have value in predicting outcome in refractory/relapsed Hodgkin lymphoma patients treated with autologous SCT. Nevertheless, a considerable proportion of pretransplant FDG-PET positive patients remains disease free and a considerable proportion of pretransplant FDG-PET negative patients develops disease relapse

  17. Study on thermal properties and crystallization behavior of electron beam irradiated ethylene vinyl acetate (EVA)/waste tyre dust (WTD) blends in the presence of polyethylene graft maleic anhydride (PEgMAH)

    SciTech Connect

    Ramli, Syuhada; Ahmad, S. H.; Ratnam, C. T.; Athirah, Nurul

    2013-11-27

    The aim of this article is to show the effects of the electron beam irradiation dose and presence of a compatibiliser on the thermal properties and crystallinity of EVA/WTD blends. The purpose of applying electron beam radiation with doses range 50 to 200 kGy and adding a compatibiliser was to enhance the compatibility of the studied blends and at the same time to investigate the possibility of using this technique in the process of recycling polymeric materials. As the compatibilisers, the polyethylene grafted maleic anhydride (PEgMAH) was utilized, they were added at the amounts of 1-5 phr respectively. The enhancement of thermal properties was accompanied by the following effects, discussed in this article: i) an irradiated EVA/WTD blend at 200kGy was found to improve the thermal properties of EVA, ii) the addition of PEgMAH in EVA/WTD blends and the subsequent irradiation allowed prevention of degradation mechanism. iii) the ΔH{sub f} and crystallinity percentage decrease at higher PEgMAH content.

  18. Study on thermal properties and crystallization behavior of electron beam irradiated ethylene vinyl acetate (EVA)/waste tyre dust (WTD) blends in the presence of polyethylene graft maleic anhydride (PEgMAH)

    NASA Astrophysics Data System (ADS)

    Ramli, Syuhada; Ratnam, C. T.; Ahmad, S. H.; Athirah, Nurul

    2013-11-01

    The aim of this article is to show the effects of the electron beam irradiation dose and presence of a compatibiliser on the thermal properties and crystallinity of EVA/WTD blends. The purpose of applying electron beam radiation with doses range 50 to 200 kGy and adding a compatibiliser was to enhance the compatibility of the studied blends and at the same time to investigate the possibility of using this technique in the process of recycling polymeric materials. As the compatibilisers, the polyethylene grafted maleic anhydride (PEgMAH) was utilized, they were added at the amounts of 1-5 phr respectively. The enhancement of thermal properties was accompanied by the following effects, discussed in this article: i) an irradiated EVA/WTD blend at 200kGy was found to improve the thermal properties of EVA, ii) the addition of PEgMAH in EVA/WTD blends and the subsequent irradiation allowed prevention of degradation mechanism. iii) the ΔHf and crystallinity percentage decrease at higher PEgMAH content.

  19. Bone grafts.

    PubMed

    Hubble, Matthew J W

    2002-09-01

    Bone grafts are used in musculoskeletal surgery to restore structural integrity and enhance osteogenic potential. The demand for bone graft for skeletal reconstruction in bone tumor, revision arthroplasty, and trauma surgery, couple with recent advances in understanding and application of the biology of bone transplantation, has resulted in an exponential increase in the number of bone-grafting procedures performed over the last decade. It is estimated that 1.5 million bone-grafting procedures are currently performed worldwide each year, compared to a fraction of that number 20 years ago. Major developments also have resulted in the harvesting, storage, and use of bone grafts and production of graft derivatives, substitutes, and bone-inducing agents.

  20. Blood irradiation: Rationale and technique

    SciTech Connect

    Lewis, M.C. )

    1990-01-01

    Upon request by the local American Red Cross, the Savannah Regional Center for Cancer Care irradiates whole blood or blood components to prevent post-transfusion graft-versus-host reaction in patients who have severely depressed immune systems. The rationale for blood irradiation, the total absorbed dose, the type of patients who require irradiated blood, and the regulations that apply to irradiated blood are presented. A method of irradiating blood using a linear accelerator is described.

  1. Pre-transplant weight loss predicts inferior outcome after allogeneic stem cell transplantation in patients with myelodysplastic syndrome.

    PubMed

    Radujkovic, Aleksandar; Becker, Natalia; Benner, Axel; Penack, Olaf; Platzbecker, Uwe; Stölzel, Friedrich; Bornhäuser, Martin; Hegenbart, Ute; Ho, Anthony D; Dreger, Peter; Luft, Thomas

    2015-10-27

    Allogeneic stem cell transplantation (alloSCT) represents a curative therapeutic option for patients with myelodysplastic syndrome (MDS), but relapse and non-relapse mortality (NRM) limit treatment efficacy. Based on our previous observation in acute myeloid leukemia we investigated the impact of pre-transplant weight loss on post-transplant outcome in MDS patients. A total of 111 patients diagnosed with MDS according to WHO criteria transplanted between 2000 and 2012 in three different transplant centers were included into the analysis. Data on weight loss were collected from medical records prior to conditioning therapy and 3-6 months earlier. Patient, disease and transplant characteristics did not differ between patients with weight loss (2-5%, n = 17; > 5%, n = 17) and those without (n = 77). In a mixed effect model, weight loss was associated with higher risk MDS (p = 0.046). In multivariable analyses, pre-transplant weight loss exceeding 5% was associated with a higher incidence of relapse (p < 0.001) and NRM (p = 0.007). Pre-transplant weight loss of 2-5% and > 5% were independent predictors of worse disease-free (p = 0.023 and p < 0.001, respectively) and overall survival (p = 0.043 and p < 0.001, respectively). Our retrospective study suggests that MDS patients losing weight prior to alloSCT have an inferior outcome after transplantation. Prospective studies addressing pre-transplant nutritional interventions are highly warranted.

  2. Successful Stem Cell Transplantation in a Patient with Pretransplant Hepatic Inflammatory Pseudotumour

    PubMed Central

    Soe, Zarni; Wong, Benjamin; Ong, Ching Ching; Teo, Lynette; Tan, Lip Kun

    2016-01-01

    Inflammatory pseudotumours (IPT) are rare benign neoplasms of unknown aetiology. We present a case of hepatic IPT which was incidentally discovered in a patient with relapsed B-acute lymphoblastic leukaemia (B-ALL) undergoing pretransplant workup. After investigation to exclude an infective cause she underwent a reduced intensity conditioning stem cell transplant (SCT) successfully and currently remains well and in remission. On repeat liver MRI after SCT, the IPT was seen to be resolving. To the best of our knowledge this is the first report of an adult patient with hepatic IPT successfully undergoing SCT. The reduction in size of the IPT after SCT also suggests an inflammatory rather than an infective aetiology for IPT. PMID:28018703

  3. Syngeneic transplantation in aplastic anemia: pre-transplant conditioning and peripheral blood are associated with improved engraftment: an observational study on behalf of the Severe Aplastic Anemia and Pediatric Diseases Working Parties of the European Group for Blood and Marrow Transplantation.

    PubMed

    Gerull, Sabine; Stern, Martin; Apperley, Jane; Beelen, Dietrich; Brinch, Lorentz; Bunjes, Donald; Butler, Andrew; Ganser, Arnold; Ghavamzadeh, Ardeshir; Koh, Mickey B; Komarnicki, Mieczyslaw; Kröger, Nicolaus; Maertens, Johan; Maschan, Alexei; Peters, Christina; Rovira, Montserrat; Sengeløv, Henrik; Socié, Gerard; Tischer, Johanna; Oneto, Rosi; Passweg, Jakob; Marsh, Judith

    2013-11-01

    Aplastic anemia is usually treated with immunosuppression or allogeneic transplant, depending on patient and disease characteristics. Syngeneic transplant offers a rare treatment opportunity with minimal transplant-related mortality, and offers an insight into disease mechanisms. We present here a retrospective analysis of all syngeneic transplants for aplastic anemia reported to the European Group for Blood and Marrow Transplantation. Between 1976 and 2009, 88 patients received 113 transplants. Most transplants (n=85) were preceded by a conditioning regimen, 22 of these including anti-thymocyte globulin. About half of transplants with data available (39 of 86) were followed by posttransplant immunosuppression. Graft source was bone marrow in the majority of cases (n=77). Transplant practice changed over time with more transplants with conditioning and anti-thymocyte globulin as well as peripheral blood stem cells performed in later years. Ten year overall survival was 93% with 5 transplant-related deaths. Graft failure occurred in 32% of transplants. Risk of graft failure was significantly increased in transplants without conditioning, and with bone marrow as graft source. Lack of posttransplant immunosuppression also showed a trend towards increased risk of graft failure, while anti-thymocyte globulin did not have an influence. In summary, syngeneic transplant is associated with a significant risk of graft failure when no conditioning is given, but has an excellent long-term outcome. Furthermore, our comparatively large series enables us to recommend the use of pre-transplant conditioning rather than not and possibly to prefer peripheral blood as a stem cell source.

  4. Impact of pretransplant rifaximin therapy on early post-liver transplant infections.

    PubMed

    Esfeh, Jamak Modaresi; Hanouneh, Ibrahim A; Koval, Christine E; Kovacs, Christopher; Dalal, Deepan S; Ansari-Gilani, Kianoush; Confer, Bradley D; Eghtesad, Bijan; Zein, Nizar N; Menon, K V Narayanan

    2014-05-01

    Bacterial and fungal infections are major causes of morbidity and mortality after liver transplantation (LT). The role of intestinal decontamination in the prevention of post-LT infections is controversial. Rifaximin is widely used for the treatment of hepatic encephalopathy. The effect of rifaximin on post-LT infections is unknown. The aim of our study was to determine the effect of rifaximin therapy in the pretransplant period on early bacterial infections (EBIs) and fungal infections within the first 30 days after LT. All adult patients who underwent LT at our institution (January 2009 to July 2011) were included in this retrospective cohort study. Patients receiving antibiotics other than pretransplant protocol antibiotics were excluded. Patients were stratified into 2 groups based on the presence or absence of rifaximin therapy for at least 2 days before LT. Infections were defined by the isolation of any bacterial or fungal organisms within 30 days of LT. Multivariate regression analysis, Student t tests, and Pearson's chi-square tests were used to compare the 2 groups. Two hundred sixty-eight patients were included, and 71 of these patients (26.5%) were on rifaximin at the time of LT. The 2 groups were comparable with respect to age, sex, race, and Model for End-Stage Liver Disease score. There were no significant differences in the rates of EBIs (30% for the non-rifaximin group and 25% for the rifaximin group, P = 0.48) or fungal infections between the 2 groups. There was no increase in antimicrobial resistance among the infecting organisms. There was no difference in survival between the rifaximin and non-rifaximin groups (98% versus 97%, P = 0.36). In conclusion, the use of rifaximin in the pre-LT period was not associated with an increased risk of bacterial or fungal infections in the early post-LT period.

  5. Skin graft

    MedlinePlus

    ... that need skin grafts to heal Venous ulcers, pressure ulcers , or diabetic ulcers that do not heal Very ... chap 17. Read More Burns Patient Instructions Preventing pressure ulcers Surgical wound care - open Review Date 3/13/ ...

  6. Immune reactivity after high-dose irradiation

    SciTech Connect

    Gassmann, W.; Wottge, H.U.; von Kolzynski, M.; Mueller-Ruchholtz, W.

    1986-03-01

    Immune reactivity after total-body irradiation was investigated in rats using skin graft rejection as the indicator system. After sublethal irradiation with 10.5 Gy (approximately 50% lethality/6 weeks) the rejection of major histocompatibility complex allogeneic skin grafts was delayed significantly compared with nonirradiated control animals (28 versus 6.5 days). In contrast, skin grafts were rejected after 7.5 days in sublethally irradiated animals and 7 days in lethally irradiated animals if additional skin donor type alloantigens--namely, irradiated bone marrow cells--were given i.v. either simultaneously or with a delay of not more than 24 hr after the above conditioning regimen. These reactions were alloantigen-specific. They were observed in six different strain combinations with varying donors and recipients. Starting on day 2 after irradiation, i.v. injection of bone marrow gradually lost its effectivity and skin grafts were no longer rejected with uniform rapidity; skin donor marrow given on days 4 or 8 did not accelerate skin graft rejection at all. These data show that for approximately 1-2 days after high-dose total-body irradiation rats are still capable of starting a vigorous immune reaction against i.v.-injected alloantigens. The phenomenon of impaired rejection of skin grafted immediately after high-dose irradiation appears to result from the poor accessibility of skin graft alloantigens during the early postirradiation phase when vascularization of the grafted skin is insufficient.

  7. Comparison of structural changes in skin and amnion tissue grafts for transplantation induced by gamma and electron beam irradiation for sterilization.

    PubMed

    Mrázová, H; Koller, J; Kubišová, K; Fujeríková, G; Klincová, E; Babál, P

    2016-06-01

    Sterilization is an important step in the preparation of biological material for transplantation. The aim of the study is to compare morphological changes in three types of biological tissues induced by different doses of gamma and electron beam radiation. Frozen biological tissues (porcine skin xenografts, human skin allografts and human amnion) were irradiated with different doses of gamma rays (12.5, 25, 35, 50 kGy) and electron beam (15, 25, 50 kGy). Not irradiated specimens served as controls. The tissue samples were then thawn and fixed in 10 % formalin, processed by routine paraffin technique and stained with hematoxylin and eosin, alcian blue at pH 2.5, orcein, periodic acid Schiff reaction, phosphotungstic acid hematoxylin, Sirius red and silver impregnation. The staining with hematoxylin and eosin showed vacuolar cytoplasmic changes of epidermal cells mainly in the samples of xenografts irradiated by the lowest doses of gamma and electron beam radiation. The staining with orcein revealed damage of fine elastic fibers in the xenograft dermis at the dose of 25 kGy of both radiation types. Disintegration of epithelial basement membrane, especially in the xenografts, was induced by the dose of 15 kGy of electron beam radiation. The silver impregnation disclosed nuclear chromatin condensation mainly in human amnion at the lowest doses of both radiation types and disintegration of the fine collagen fibers in the papillary dermis induced by the lowest dose of electron beam and by the higher doses of gamma radiation. Irradiation by both, gamma rays and the electron beam, causes similar changes on cells and extracellular matrix, with significant damage of the basement membrane and of the fine and elastic and collagen fibers in the papillary dermis, the last caused already by low dose electron beam radiation.

  8. Pre-transplant diabetes mellitus is a risk factor for non-relapse mortality, especially infection-related mortality, after allogeneic hematopoietic SCT.

    PubMed

    Takano, K; Fuji, S; Uchida, N; Ogawa, H; Ohashi, K; Eto, T; Sakamaki, H; Morishima, Y; Kato, K; Suzuki, R; Fukuda, T

    2015-04-01

    Diabetes mellitus (DM) is a factor in the hematopoietic cell transplantation-comorbidity index. However, the impact of pre-transplant DM on morbidity and cause-specific non-relapse mortality (NRM) remains unclear. We performed a retrospective study with registry data that included a total of 7626 patients who underwent their first allogeneic hematopoietic SCT (HSCT) between 2007 and 2010. The median age was 44 years (range 0-88). Compared with patients without pre-transplant DM (non-DM group, n=7248), patients with pre-transplant DM (DM group, n=378) were older and were more likely to have high-risk disease, a reduced-intensity conditioning regimen and GVHD prophylaxis using tacrolimus. Multivariate analyses showed that pre-transplant DM was associated with increased risks of NRM (hazard ratio (HR)1.46, 95% confidence interval (CI) 1.21-1.76, P<0.01) and infection-related NRM (HR 2.08, 95% CI 1.58-2.73, P<0.01). The presence of pre-transplant DM was associated with an increased risk of overall mortality in a multivariate analysis (HR 1.55, 95% CI 1.35-1.78, P<0.01). In conclusion, pre-transplant DM was a risk factor for NRM, particularly infection-related mortality, after allogeneic HSCT. To improve the clinical outcome in patients with DM, the benefits of strict infection control and appropriate glycemic control should be explored in future trials.

  9. Synergistic photocatalytic inactivation mechanisms of bacteria by graphene sheets grafted plasmonic AgAgX (X = Cl, Br, I) composite photocatalyst under visible light irradiation.

    PubMed

    Xia, Dehua; An, Taicheng; Li, Guiying; Wang, Wanjun; Zhao, Huijun; Wong, Po Keung

    2016-08-01

    By coupling graphene sheet and plasmonic photocatalysis technologies, a series of AgAgX/RGOs (X = Cl, Br, I; RGO = reduced graphene oxide) composites were prepared and found to be efficient antimicrobial agents for water disinfection upon visible light. Attributed to the efficient charge transfer by RGO sheets, the optimum AgAgBr/0.5% RGO could completely inactivate 2 × 10(7) cfu mL(-1) of Escherichia coli within 8 min, much faster than bare AgAgBr within 35 min. The synergistic antimicrobial mechanism of AgAgBr/0.5% RGO was studied by Ag(+) ions release evaluation, radical scavengers study, and radical determination. The enhanced photocatalytic activity of irradiated AgAgBr/0.5% RGO originated from the synergistic activities of its three components including Ag, AgBr and RGO, and the proposed mechanisms contained enhanced attraction by RGO followed by two pathways: primary oxidative stress caused by plasma induced reactive species like H2O2 and bactericidal effect of released Ag(+) ions. Furthermore, characterization of E. coli cells using SEM, fluorescent microscopy, and cytoplasmic substance leakage illustrated that VL irradiated AgAgBr/0.5% RGO could not only cause metabolic dysfunction but also destroy the cell envelope and biomolecular, while irradiated Ag(+) ions play a differential bactericidal action with a limited metabolic injury and no cell-membrane damage. The present work provides an efficient water disinfection technology and also opens a new idea in studying the antimicrobial mechanism of plasmonic photocatalyst.

  10. Impact of Pre-transplant Therapy and Depth of Disease Response prior to Autologous Transplantation for Multiple Myeloma

    PubMed Central

    Vij, Ravi; Kumar, Shaji; Zhang, Mei-Jie; Zhong, Xiaobo; Huang, Jiaxing; Dispenzieri, Angela; Abidi, Muneer H.; Bird, Jennifer M.; Freytes, César O.; Gale, Robert Peter; Kindwall-Keller, Tamila L.; Kyle, Robert A.; Landsburg, Daniel J.; Lazarus, Hillard M.; Munker, Reinhold; Roy, Vivek; Sharma, Manish; Vogl, Dan T.; Wirk, Baldeep; Hari, Parameswaran N.

    2014-01-01

    Patients with multiple myeloma (MM), who are eligible for autologous stem cell transplantation (ASCT), typically receive a finite period of initial therapy prior to ASCT. It is not clear if patients with suboptimal (less than a partial) response to initial therapy benefit from additional alternative therapy with intent to maximize pre-transplant response. We identified 539 patients with MM who had an ASCT after having achieved less than a partial response (PR) to first line induction chemotherapy between 1995 and 2010. These patients were then divided into two groups: those who received additional salvage chemotherapy prior to ASCT (n=324) and those who had no additional salvage chemotherapy immediately prior to ASCT (n=215). Additional pre-transplant chemotherapy resulted in deepening responses in 68% (complete response in 8% and PR in 60%). On multivariate analysis there was no impact of pre-transplant salvage chemotherapy on treatment related mortality (TRM), risk for relapse, progression free or overall survival. In conclusion, for patients achieving a less than PR to initial induction therapy including with novel agent combinations, additional pre-ASCT salvage chemotherapy improved the depth of response and pre-ASCT disease status but was not associated with survival benefit. PMID:25445028

  11. Pretransplant HLA mistyping in diagnostic samples of acute myeloid leukemia patients due to acquired uniparental disomy.

    PubMed

    Dubois, V; Sloan-Béna, F; Cesbron, A; Hepkema, B G; Gagne, K; Gimelli, S; Heim, D; Tichelli, A; Delaunay, J; Drouet, M; Jendly, S; Villard, J; Tiercy, J-M

    2012-09-01

    Although acquired uniparental disomy (aUPD) has been reported in relapse acute myeloid leukemia (AML), pretransplant aUPD involving chromosome 6 is poorly documented. Such events could be of interest because loss of heterozygosity (LOH) resulting from aUPD in leukemic cells may lead to erroneous results if HLA typing for hematopoietic stem cell donor searches is performed on blood samples drawn during blastic crisis. We report here six AML patients whose HLA typing was performed on DNA extracted from peripheral blood obtained at diagnosis. We observed LOH involving the entire HLA region (three patients), HLA-A, B, C (two patients) and HLA-A only (one patient). An array-comparative genomic hybridization showed that copy number was neutral for all loci, thus revealing partial aUPD of chromosome 6p21. When HLA typing was performed on remission blood samples both haplotypes were detected. A 3-4% LOH incidence was estimated in AML patients with high blast counts. Based on DNA mixing experiments, we determined by PCR sequence-specific oligonucleotide hybridization on microbeads arrays a detection threshold for HLA-A, B, DRB1 heterozygosity in blood samples with <80% blasts. Because aUPD may be partial, any homozygous HLA result should be confirmed by a second typing performed on buccal swabs or on blood samples from the patient in remission.

  12. Modification of microcrystalline cellulose by gamma radiation-induced grafting

    NASA Astrophysics Data System (ADS)

    Madrid, Jordan F.; Abad, Lucille V.

    2015-10-01

    Modified microcrystalline cellulose (MCC) was prepared through gamma radiation-induced graft polymerization of glycidyl methacrylate (GMA). Simultaneous grafting was employed wherein MCC with GMA in methanol was irradiated with gamma radiation in nitrogen atmosphere. The effects of different experimental factors such as monomer concentration, type of solvent and absorbed dose on the degree of grafting, Dg, were studied. The amount of grafted GMA, expressed as Dg, was determined gravimetrically. Information from grafted samples subjected to Fourier transformed infrared spectroscopy (FTIR) in attenuated total reflectance (ATR) mode showed peaks corresponding to GMA which indicates successful grafting. The X-ray diffraction (XRD) analysis revealed that the crystalline region of MCC was not adversely affected after grafting with GMA. The thermogravimetric analysis (TGA) data showed that the decomposition of grafted MCC occurred at higher temperature compared to the base MCC polymer.

  13. Pretransplant Factors and Associations with Postoperative Respiratory Failure, ICU Length of Stay, and Short-Term Survival after Liver Transplantation in a High MELD Population

    PubMed Central

    Pedersen, Mark R.; Choi, Myunghan; Brink, Jeffrey A.

    2016-01-01

    Changes in distribution policies have increased median MELD at transplant with recipients requiring increasing intensive care perioperatively. We aimed to evaluate association of preoperative variables with postoperative respiratory failure (PRF)/increased intensive care unit length of stay (ICU LOS)/short-term survival in a high MELD cohort undergoing liver transplant (LT). Retrospective analysis identified cases of PRF and increased ICU LOS with recipient, donor, and surgical variables examined. Variables were entered into regression with end points of PRF and ICU LOS > 3 days. 164 recipients were examined: 41 (25.0%) experienced PRF and 74 (45.1%) prolonged ICU LOS. Significant predictors of PRF with univariate analysis: BMI > 30, pretransplant MELD, preoperative respiratory failure, LVEF < 50%, FVC < 80%, intraoperative transfusion > 6 units, warm ischemic time > 4 minutes, and cold ischemic time > 240 minutes. On multivariate analysis, only pretransplant MELD predicted PRF (OR 1.14, p = 0.01). Significant predictors of prolonged ICU LOS with univariate analysis are as follows: pretransplant MELD, FVC < 80%, FEV1 < 80%, deceased donor, and cold ischemic time > 240 minutes. On multivariate analysis, only pretransplant MELD predicted prolonged ICU LOS (OR 1.28, p < 0.001). One-year survival among cohorts with PRF and increased ICU LOS was similar to subjects without. Pretransplant MELD is a robust predictor of PRF and ICU LOS. Higher MELDs at LT are expected to increase need for ICU utilization and modify expectations for recovery in the immediate postoperative period. PMID:27980860

  14. Pretransplant Factors and Associations with Postoperative Respiratory Failure, ICU Length of Stay, and Short-Term Survival after Liver Transplantation in a High MELD Population.

    PubMed

    Pedersen, Mark R; Choi, Myunghan; Brink, Jeffrey A; Seetharam, Anil B

    2016-01-01

    Changes in distribution policies have increased median MELD at transplant with recipients requiring increasing intensive care perioperatively. We aimed to evaluate association of preoperative variables with postoperative respiratory failure (PRF)/increased intensive care unit length of stay (ICU LOS)/short-term survival in a high MELD cohort undergoing liver transplant (LT). Retrospective analysis identified cases of PRF and increased ICU LOS with recipient, donor, and surgical variables examined. Variables were entered into regression with end points of PRF and ICU LOS > 3 days. 164 recipients were examined: 41 (25.0%) experienced PRF and 74 (45.1%) prolonged ICU LOS. Significant predictors of PRF with univariate analysis: BMI > 30, pretransplant MELD, preoperative respiratory failure, LVEF < 50%, FVC < 80%, intraoperative transfusion > 6 units, warm ischemic time > 4 minutes, and cold ischemic time > 240 minutes. On multivariate analysis, only pretransplant MELD predicted PRF (OR 1.14, p = 0.01). Significant predictors of prolonged ICU LOS with univariate analysis are as follows: pretransplant MELD, FVC < 80%, FEV1 < 80%, deceased donor, and cold ischemic time > 240 minutes. On multivariate analysis, only pretransplant MELD predicted prolonged ICU LOS (OR 1.28, p < 0.001). One-year survival among cohorts with PRF and increased ICU LOS was similar to subjects without. Pretransplant MELD is a robust predictor of PRF and ICU LOS. Higher MELDs at LT are expected to increase need for ICU utilization and modify expectations for recovery in the immediate postoperative period.

  15. Proximal Tibial Bone Graft

    MedlinePlus

    ... All Site Content AOFAS / FootCareMD / Treatments Proximal Tibial Bone Graft Page Content What is a bone graft? Bone grafts may be needed for various ... the proximal tibia. What is a proximal tibial bone graft? Proximal tibial bone graft (PTBG) is a ...

  16. End-Stage Renal Disease after Liver Transplantation in Patients with Pre-Transplant Chronic Kidney Disease

    PubMed Central

    Bahirwani, Ranjeeta; Forde, Kimberly A.; Mu, Yifei; Lin, Fred; Reese, Peter; Goldberg, David; Abt, Peter; Reddy, K Rajender; Levine, Matthew

    2014-01-01

    Renal dysfunction prior to liver transplantation has a marked impact on post-transplant kidney outcomes. The aim of this study was to assess post-transplant renal function in patients with chronic kidney disease (CKD) receiving orthotopic liver transplantation (OLT) alone. METHODS Retrospective review of 40 OLT recipients with pre-transplant CKD (serum creatinine ≥ 2 mg/dl for at least 3 months) at the University of Pennsylvania from February 2002 to July 2010. Primary outcome was estimated glomerular filtration rate (eGFR) up to 3 years post-transplant. Secondary outcomes included incidence of stage 4 CKD (eGFR < 30 ml/min), need for renal replacement therapy (RRT), meeting criteria for kidney transplant listing (eGFR ≤ 20 ml/min), and mortality. RESULTS Median patient age was 56.5 years and 48% patients had pre-transplant diabetes. Median serum creatinine at transplant was 2.7 mg/dl (eGFR 24 ml/min). Median eGFR at 1, 2, and 3 years post-transplant was 35, 34, and 37 ml/min respectively. Twelve patients (30%) required RRT at a median of 1.21 years posttransplant and 16 (40%) achieved an eGFR ≤ 20 ml/min at 1.09 years post-transplant. Mortality was 35% at a median of 1.60 years post-transplant. CONCLUSIONS OLT recipients with pre-transplant CKD have a substantial burden of post-transplant renal dysfunction and high short-term mortality, questioning the rationale for OLT alone in this population. PMID:24382253

  17. Human umbilical cord blood-derived stromal cells, a new resource in the suppression of acute graft-versus-host disease in haploidentical stem cell transplantation in sublethally irradiated mice.

    PubMed

    Zhang, Cheng; Chen, Xing-Hua; Zhang, Xi; Gao, Lei; Kong, Pei-Yan; Peng, Xian-gui; Liang, Xue; Gao, Li; Gong, Yi; Wang, Qing-Yu

    2011-04-15

    Human umbilical cord blood-derived stromal cells (hUCBDSCs), a novel population isolated from CD34(+) cells by our laboratory, exerted an immunosuppressive effect on xenogenic T cells. This study aimed to investigate whether hUCBDSCs play a critical role in the suppression of acute graft-versus-host disease (aGVHD). The hUCBDSCs were co-cultured with splenocytes (SPCs) of donor C57BL/6 mice. The aGVHD in the recipient (B6×BALB/c) F1 mice was induced by the infusion of bone marrow cells and SPCs from donor mice following sublethal irradiation. The shift in vivo for hUCBDSCs was detected. The proliferation and cell cycle of SPCs were tested by cell counting kit-8 and flow cytometry, respectively. The expression of CD49b natural killer (NK) cells and CD3 T cells was detected by flow cytometry in co-culture and post-transplantation. IL-4, and IFN-γ were detected by ELISA in the serum of co-culture and post-transplantation. The survival time, body weight, clinical score, and histopathological score were recorded for mice post-transplantation. The hUCBDSCs promoted the proliferation of SPCs and significantly increased the ratio of the S and G(2)/M phase (p < 0.05). The hUCBDSCs significantly increased the expression of CD49b NK cells and IL-4 protein and decreased the expression of CD3 T cells and IFN-γ protein both in vitro and in vivo. The survival time of mice with co-transplantation of hUCBDSCs was significantly prolonged, and decreased clinical and histopathological scores were also observed. The hUCBDSCs were continually detected in the target organs of GVHD. These results suggest that hUCBDSCs possess the capability of suppressing aGVHD, possibly via their influence on CD3 T cells, NK cells, and cytokines.

  18. Coronary Artery Bypass Grafting

    MedlinePlus

    ... from the NHLBI on Twitter. What Is Coronary Artery Bypass Grafting? Coronary artery bypass grafting (CABG) is ... bypass multiple coronary arteries during one surgery. Coronary Artery Bypass Grafting Figure A shows the location of ...

  19. Syngeneic transplantation in aplastic anemia: pre-transplant conditioning and peripheral blood are associated with improved engraftment: an observational study on behalf of the Severe Aplastic Anemia and Pediatric Diseases Working Parties of the European Group for Blood and Marrow Transplantation

    PubMed Central

    Gerull, Sabine; Stern, Martin; Apperley, Jane; Beelen, Dietrich; Brinch, Lorentz; Bunjes, Donald; Butler, Andrew; Ganser, Arnold; Ghavamzadeh, Ardeshir; Koh, Mickey B; Komarnicki, Mieczyslaw; Kröger, Nicolaus; Maertens, Johan; Maschan, Alexei; Peters, Christina; Rovira, Montserrat; Sengeløv, Henrik; Socié, Gerard; Tischer, Johanna; Oneto, Rosi; Passweg, Jakob; Marsh, Judith

    2013-01-01

    Aplastic anemia is usually treated with immunosuppression or allogeneic transplant, depending on patient and disease characteristics. Syngeneic transplant offers a rare treatment opportunity with minimal transplant-related mortality, and offers an insight into disease mechanisms. We present here a retrospective analysis of all syngeneic transplants for aplastic anemia reported to the European Group for Blood and Marrow Transplantation. Between 1976 and 2009, 88 patients received 113 transplants. Most transplants (n=85) were preceded by a conditioning regimen, 22 of these including anti-thymocyte globulin. About half of transplants with data available (39 of 86) were followed by posttransplant immunosuppression. Graft source was bone marrow in the majority of cases (n=77). Transplant practice changed over time with more transplants with conditioning and anti-thymocyte globulin as well as peripheral blood stem cells performed in later years. Ten year overall survival was 93% with 5 transplant-related deaths. Graft failure occurred in 32% of transplants. Risk of graft failure was significantly increased in transplants without conditioning, and with bone marrow as graft source. Lack of posttransplant immunosuppression also showed a trend towards increased risk of graft failure, while anti-thymocyte globulin did not have an influence. In summary, syngeneic transplant is associated with a significant risk of graft failure when no conditioning is given, but has an excellent long-term outcome. Furthermore, our comparatively large series enables us to recommend the use of pre-transplant conditioning rather than not and possibly to prefer peripheral blood as a stem cell source. PMID:23894010

  20. Photoinduced graft-copolymer synthesis and characterization of methacrylic acid onto natural biodegradable lignocellulose fiber.

    PubMed

    Khan, Ferdous

    2004-01-01

    UV radiation induced graft copolymerization of methacrylic acid onto natural lignocellulose (jute) fiber was carried out both by "simultaneous irradiation and grafting" and by preirradiation methods using 1-hydroxycyclohexyl-phenyl ketone as a photoinitiator. In the "simultaneous irradiation and grafting" method, the variation of graft weight with UV-radiation time, monomer concentration, and the concentration of photoinitiator was investigated. In the case of the preirradiation method, the incorporation of 2-methyl-2-propene 1-sulfonic acid, sodium salt, into the grafting reaction solution played a most important role in suppressing the homopolymer/gel formation and facilitating graft copolymerization. The optimum value of the reaction parameters on the percentage of grafting was evaluated. In comparison, results showed that the method of graft-copolymer synthesis has significant influence on graft weight. The study on the mechanical and thermal properties of grafted samples was conducted. The results showed that the percentage of grafting has a significant effect on the mechanical and thermal properties in the case of grafted samples. Considering the water absorption property, the jute-poly(methacrylic acid)-grafted sample showed a maximum up to 42% increase in hydrophilicity with respect to that of the "as received" sample. Attenuated total reflection infrared studies indicate that the estimation of the degree of grafting could be achieved by correlating band intensities with the percent graft weight.

  1. Total lymphoid irradiation

    SciTech Connect

    Sutherland, D.E.; Ferguson, R.M.; Simmons, R.L.; Kim, T.H.; Slavin, S.; Najarian, J.S.

    1983-05-01

    Total lymphoid irradiation by itself can produce sufficient immunosuppression to prolong the survival of a variety of organ allografts in experimental animals. The degree of prolongation is dose-dependent and is limited by the toxicity that occurs with higher doses. Total lymphoid irradiation is more effective before transplantation than after, but when used after transplantation can be combined with pharmacologic immunosuppression to achieve a positive effect. In some animal models, total lymphoid irradiation induces an environment in which fully allogeneic bone marrow will engraft and induce permanent chimerism in the recipients who are then tolerant to organ allografts from the donor strain. If total lymphoid irradiation is ever to have clinical applicability on a large scale, it would seem that it would have to be under circumstances in which tolerance can be induced. However, in some animal models graft-versus-host disease occurs following bone marrow transplantation, and methods to obviate its occurrence probably will be needed if this approach is to be applied clinically. In recent years, patient and graft survival rates in renal allograft recipients treated with conventional immunosuppression have improved considerably, and thus the impetus to utilize total lymphoid irradiation for its immunosuppressive effect alone is less compelling. The future of total lymphoid irradiation probably lies in devising protocols in which maintenance immunosuppression can be eliminated, or nearly eliminated, altogether. Such protocols are effective in rodents. Whether they can be applied to clinical transplantation remains to be seen.

  2. Nickel adsorption by sodium polyacrylate-grafted activated carbon.

    PubMed

    Ewecharoen, A; Thiravetyan, P; Wendel, E; Bertagnolli, H

    2009-11-15

    A novel sodium polyacrylate grafted activated carbon was produced by using gamma radiation to increase the number of functional groups on the surface. After irradiation the capacity for nickel adsorption was studied and found to have increased from 44.1 to 55.7 mg g(-1). X-ray absorption spectroscopy showed that the adsorbed nickel on activated carbon and irradiation-grafted activated carbon was coordinated with 6 oxygen atoms at 2.04-2.06 A. It is proposed that this grafting technique could be applied to other adsorbents to increase the efficiency of metal adsorption.

  3. Study on chemical, UV and gamma radiation-induced grafting of 2-hydroxyethyl methacrylate onto chitosan

    NASA Astrophysics Data System (ADS)

    Casimiro, M. H.; Botelho, M. L.; Leal, J. P.; Gil, M. H.

    2005-04-01

    In the present study, 2-hydroxyethyl methacrylate has been grafted onto chitosan by using either chemical initiation, or photo-induction or gamma radiation-induced polymerisation, all under heterogeneous conditions. The evidence of grafting was provided by Fourier transform infrared spectroscopy and thermal analysis. The results concerning the effect of initiator concentration, initial monomer concentration and dose rate influencing on the yield of grafting reactions are presented. These suggest that gamma irradiation is the method that leads to higher yields of grafting.

  4. Moderator's view: Pretransplant weight loss in dialysis patients: cum grano salis.

    PubMed

    Sever, Mehmet Sukru; Zoccali, Carmine

    2015-11-01

    A high Body Mass Index (BMI) predicts delayed graft function, all cause and cardiovascular death after transplantation but such risk excess is apparently confined to patients included in studies performed before 2000. Perhaps with the exception of morbid obesity (BMI > 40), clinical outcomes in transplanted obese patients are definitely better than in listed dialysis patients who don't receive a renal transplant. Furthermore the new Scientific Registry of Transplant Recipients (SRTR) risk calculator incorporates BMI into the prediction model of the global risk for the graft's and patient's survival appropriately framing the risk of obesity in a multidimensional risk context. In the aggregate, available knowledge suggests that clinical decisions on weight loss before transplantation should be context specific. Renal transplant patients from living donors have substantial better survival in comparison to well matched dialysis patients listed for the same intervention at all BMI categories. Therefore renal transplantation in obese patients with a living donor may be prioritized. The attitude of fully informed obese patients at accepting the risk driven by transplantation, the experience of the surgical team with obese patients (including also robotic surgery) are of obvious importance. Renal transplantation should be timely considered when reasonable attempts at weight loss failed or appear overtly unrealistic. Transplantation in morbidly obese patients with BMI > 40, a category where the survival advantage of transplantation vs dialysis is probably small and still uncertain, particularly so in African-Americans, should be deferred until significant weight loss is achieved.

  5. Electrostrictive Graft Elastomers

    NASA Technical Reports Server (NTRS)

    Su, Ji (Inventor); Harrison, Joycelyn S. (Inventor); St.Clair, Terry L. (Inventor)

    2003-01-01

    An electrostrictive graft elastomer has a backbone molecule which is a non-crystallizable, flexible macromolecular chain and a grafted polymer forming polar graft moieties with backbone molecules. The polar graft moieties have been rotated by an applied electric field, e.g., into substantial polar alignment. The rotation is sustained until the electric field is removed. In another embodiment, a process for producing strain in an elastomer includes: (a) providing a graft elastomer having a backbone molecule which is a non-crystallizable, flexible macromolecular chain and a grafted polymer forming polar graft moieties with backbone molecules; and (b) applying an electric field to the graft elastomer to rotate the polar graft moieties, e.g., into substantial polar alignment.

  6. Preirradiation grafting of ethylene vinyl acetate copolymer resins

    NASA Astrophysics Data System (ADS)

    Ringrose, B. J.; Kronfli, E.

    1999-07-01

    Acrylic acid was graft copolymerised on to EVA powdered resins containing 9%, 18% and 28% vinyl acetate. A preirradiation grafting method was used and the effect on graft level of varying the parameters of gamma irradiation dose (2-50 kGy), dose rate (0.5-5 kGy h -1), monomer concentration (2.5-25%) and grafting time (1-4 h) and temperature (35-98°C) was investigated. The graft copolymer resins were converted into film and characterised in terms of their hydrophilicity and electrolytic resistance in alkaline solutions. Depending on the vinyl acetate content and rheological properties of the base EVA copolymer, high graft weight resins can be converted into semipermeable films suitable for a range of applications including battery separator membranes and topical medical dressings.

  7. Radiation-induced grafting of sweet sorghum stalk for copper(II) removal from aqueous solution.

    PubMed

    Dong, Jing; Hu, Jun; Wang, Jianlong

    2013-11-15

    The influence of main components (cellulose, hemicellulose and lignin) of the sweet sorghum stalk on radiation-induced grafting reaction and adsorption of copper from aqueous solution was investigated. Sweet sorghum stalk was grafted with acrylic acid induced by γ-irradiation. The results showed that the grafted stalk contained 1.6 mmol/g carboxyl groups, and its maximal adsorption capacity was 13.32 mg/g. The cellulose, hemicellulose and lignin of the raw materials were confirmed to involve in grafting reaction through comparing the grafting yield and the structure of the grafted materials. Both the structure and the composition of the sweet sorghum stalk had influence on the grafting reaction and adsorption capacity. The adsorption capacity of the grafted sweet sorghum stalk increased about five times, and the adsorption isotherm of the grafted materials conformed to the Langmuir model. The main mechanism for copper adsorption involved in ion exchange.

  8. Antibody Subclass Repertoire and Graft Outcome Following Solid Organ Transplantation

    PubMed Central

    Valenzuela, Nicole M.; Hickey, Michelle J.; Reed, Elaine F.

    2016-01-01

    Long-term outcomes in solid organ transplantation are constrained by the development of donor-specific alloantibodies (DSA) against human leukocyte antigen (HLA) and other targets, which elicit antibody-mediated rejection (ABMR). However, antibody-mediated graft injury represents a broad continuum, from extensive complement activation and tissue damage compromising the function of the transplanted organ, to histological manifestations of endothelial cell injury and mononuclear cell infiltration but without concurrent allograft dysfunction. In addition, while transplant recipients with DSA as a whole fare worse than those without, a substantial minority of patients with DSA do not experience poorer graft outcome. Taken together, these observations suggest that not all DSA are equally pathogenic. Antibody effector functions are controlled by a number of factors, including antibody concentration, antigen availability, and antibody isotype/subclass. Antibody isotype is specified by many integrated signals, including the antigen itself as well as from antigen-presenting cells or helper T cells. To date, a number of studies have described the repertoire of IgG subclasses directed against HLA in pretransplant patients and evaluated the clinical impact of different DSA IgG subclasses on allograft outcome. This review will summarize what is known about the repertoire of antibodies to HLA and non-HLA targets in transplantation, focusing on the distribution of IgG subclasses, as well as the general biology, etiology, and mechanisms of injury of different humoral factors. PMID:27822209

  9. Radiation-induced grafting of styrene onto polyimide ion track membranes

    NASA Astrophysics Data System (ADS)

    Friese, K.; Mehnert, R.; Placek, V.; Trautmann, C.; Angert, N.; Spohr, R.; Trautmann, Ch.

    1995-11-01

    The radiation induced grafting of styrene onto polyimide was carried out by applying the method of preirradiation as well as the simultaneous irradiation of polymer and monomer. The polymerization was initiated by gamma irradiation and by swift heavy ions. The result of these experiments was that no grafting occurs by applying the preirradiation method but grafting (up to 30%) is obtained by using the simultaneous method. For an explanation some ESR-experiments were carried out. We found that even the non-irradiated polyimide has a clear ESR signal with two different lines, probably as a result of absorbed oxygen and thermally formed radicals. The preirradiation method was not successful, because no peroxy-radicals are formed after irradiation. Grafting by initiation with heavy ions results in small grafting yields, but etching of the membranes is markedly reduced.

  10. Proton exchange membranes prepared by grafting of styrene/divinylbenzene into crosslinked PTFE membranes

    NASA Astrophysics Data System (ADS)

    Li, Jingye; Ichizuri, Shogo; Asano, Saneto; Mutou, Fumihiro; Ikeda, Shigetoshi; Iida, Minoru; Miura, Takaharu; Oshima, Akihiro; Tabata, Yoneho; Washio, Masakazu

    2005-07-01

    Thin PTFE membranes were prepared by coating the PTFE dispersion onto the aluminum films. Thus the thin crosslinked PTFE (RX-PTFE) membranes were obtained by means of electron beam irradiation above the melting temperature of PTFE under oxygen-free atmosphere. The RX-PTFE membranes were pre-irradiated and grafted by styrene with or without divinylbenzene (DVB) in liquid phase. The existence of DVB accelerated the initial grafting rate. The styrene grafted RX-PTFE membranes are white colored, on the other hand, the styrene/DVB grafted RX-PTFE membranes are colorless. The proton exchange membranes (PEMs) were obtained by sulfonating the grafted membranes using chlorosulfonic acid. The ion exchange capacity (IEC) values of the PEMs ranging from 1.5 to 2.8 meq/g were obtained. The PEMs made from the styrene/DVB grafted membranes showed higher chemical stability than those of the styrene grafted membranes under oxidative circumstance.

  11. Fulminant transfusion-associated graft-versus-host disease in a premature infant

    SciTech Connect

    Berger, R.S.; Dixon, S.L.

    1989-05-01

    A fatal case of transfusion-associated graft-versus-host disease developed in a premature infant after receiving several blood products, including nonirradiated white blood cells. Transfusion-associated graft-versus-host disease can be prevented. Irradiation of blood products is the least controversial and most effective method. Treatment was unsuccessful in most reported cases of transfusion-associated graft-versus-host disease. Therefore irradiation of blood products before transfusing to patients susceptible to transfusion-associated graft-versus-host disease is strongly recommended.

  12. Immobilization of enzymes and antibodies to radiation grafted polymers for therapeutic and diagnostic applications

    NASA Astrophysics Data System (ADS)

    Hoffman, Allan S.; Gombotz, Wayne R.; Uenoyama, Satoshi; Dong, Liang C.; Schmer, Gottfried

    Pre-irradiation and mutual radiation grafting were employed to produce poly(methacrylic acid) (MAAc) hydrogels on polypropylene/polyethylene (PP/PE) copolymer films, PP films and porous PP fibers of a plasma filter. A diphenyl picryl hydrazyl (DPPH) assay was developed to measure the surface peroxide concentration of the pre-irradiated PP/PE films prior to grafting. Mutually grafted porous PP fibers were used for subsequent immobilization of L-asparaginase while the mutually grafted PP/PE films were used to immobilize a schistosoma monoclonal antibody.

  13. Grafting chitosan and polyHEMA on carbon nanotubes surfaces: "grafting to" and "grafting from" methods.

    PubMed

    Mahmoodian, Hossein; Moradi, Omid; Shariatzadeh, Behnam

    2014-02-01

    We report a simple method for engineering chitosan (CS) functionalized multi-walled carbon nanotube (MWCNT) composites with a biomedically important polymer, poly-2-hydroxyethyl methacrylate (polyHEMA), by chemical grafting HEMA monomers via free radical polymerization. Functionalization of CS and polyHEMA occurred in three steps. First, using microwave irradiation, CS was grafted onto the surface and sidewall of the carbon nanotubes. Second, HEMA monomers were grafted onto the polymeric matrix surface. The final step involved free radical polymerization of HEMA monomers. Composite synthesis was confirmed by Fourier transform infrared (FTIR) spectroscopy. Moreover, the presence of polyHEMA on the surface of the CS functionalized carbon nanotubes was confirmed by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and thermo gravimetric analysis (TGA) analyses. Furthermore, in the aqueous phase, our novel composites exhibited higher dispersibility compared with pristine MWCNTs. Considering the biomedical importance of polyHEMA and CS polymers, we expect these materials to be useful in the pharmaceutical industry as novel biomaterial composites with potential applications in drug delivery.

  14. Apoptotic signaling through Fas and TNF receptors ameliorates GVHD in mobilized peripheral blood grafts.

    PubMed

    Mizrahi, K; Yaniv, I; Ash, S; Stein, J; Askenasy, N

    2014-05-01

    Mobilized peripheral blood (mPB) is a prevalent source of hematopoietic progenitors for transplantation; however, allogeneic and haploidentical transplants are often accompanied by severe GVHD. Following the observation that murine GVHD is ameliorated by pretransplant donor cell exposure to Fas-ligand (FasL) without host-specific sensitization, we assessed the susceptibility of mPB cells to spontaneous and receptor-induced apoptosis as a possible approach to GVHD prophylaxis. Short incubation for 4 h resulted in spontaneous apoptosis of 50% of the T and B lymphocytes and 60% myeloid cells. Although expression of Fas and TNF-R1 was proportionate to fractional apoptosis, cell death was dominated by spontaneous apoptosis. Functional assays revealed that the death receptors modulated mPB graft composition as compared with incubation in medium, without detectable quantitative variations. Removal of dead cells increased the frequency of mPB myeloid progenitors (P<0.001 vs medium), and recipients of mPB exposed to death ligands displayed reduced GVHD (P<0.01 vs medium) and improved survival following lipopolysacharide stimulation. mPB grafts exposed to the apoptotic challenge retained SCID reconstituting potential and graft versus tumor activity. These data emphasize that short-term exposure of mPB grafts to an apoptotic challenge is effective in reduction of GVHD effector activity.

  15. Temperature- and pH-sensitive interpenetrating polymer networks grafted on PP: Cross-linking irradiation dose as a critical variable for the performance as vancomycin-eluting systems

    NASA Astrophysics Data System (ADS)

    Muñoz-Muñoz, Franklin; Ruiz, Juan-Carlos; Alvarez-Lorenzo, Carmen; Concheiro, Angel; Bucio, Emilio

    2012-05-01

    This work focuses on the effect of gamma-ray radiation conditions on the stimuli-responsiveness and drug-eluting performance of polypropylene (PP) substrates grafted with interpenetrating networks of N-isopropylacrylamide (NIPAAm) and acrylic acid (AAc). PNIPAAm was cross-linked applying 10-100 kGy doses in the presence and absence of the chemical cross-linker N,N'-methylenebisacrylamide (MBAAm). Then, the net-PP-g-PNIPAAm was interpenetrated with PAAc synthesized under a 2.5 kGy dose to obtain net-PP-g-PNIPAAm-inter-net-PAAc films. The amount of grafted PNIPAAm (80%, 125% and 145% levels) and the cross-linking radiation dose (10, 40 and 70 kGy levels) strongly determine the interpenetration of PAAc, the swelling degree, the amount of vancomycin loaded and its release rate. The chemical cross-linker only caused a minor decrease in the degree of swelling. The higher the PNIPAAm grafted on PP and the lower the cross-linking radiation dose, the more the PAAc in the IPN and, consequently, the higher the vancomycin loaded through specific interactions and the more sustained the release (>8 h). The films possessing these features exhibited vancomycin release rate per surface unit suitable to prevent bacterial growth. Thus, adequate tuning of the radiation doses during grafting and cross-linking of the PNIPAAm networks may enable to achieve surface-modified materials for medical devices with an antibiofilm performance.

  16. Allogeneic stem cell transplant for adults with myelodysplastic syndromes: relevance of pre-transplant disease status.

    PubMed

    Busca, Alessandro; Pecoraro, Clara; Giaccone, Luisa; Bruno, Benedetto; Allione, Bernardino; Corsetti, Maria Teresa; Pini, Massimo; Marmont, Filippo; Audisio, Ernesta; D'Ardia, Stefano; Frairia, Chiara; Castiglione, Anna; Ciccone, Giovannino; Levis, Alessandro; Vitolo, Umberto; Falda, Michele

    2014-04-01

    The aim of the present study was to investigate the outcome of 94 adult patients with myelodysplasia (MDS) who received an allogeneic stem cell transplant between January 1995 and September 2010 in two Italian hematology centers. At the time of transplant, 53 patients (56%) had relapsed/refractory disease. The cumulative incidence of grades II-IV acute graft-versus-host disease (GVHD) and chronic GVHD was 33% (95% confidence interval [CI] 21-45%) and 78% (95% CI 66-90%), respectively. The cumulative incidence of transplant-related mortality (TRM) at 100 days was 13% (95% CI 6-21%). The 2-year progression free survival (PFS) and overall survival (OS) were 41% (95% CI 31-51%) and 49% (95% CI 38-59%), respectively. On multivariate analysis, advanced disease stage at transplant was the major independent variable associated with an inferior 2-year PFS (HR 3.66, 95% CI 1.98-6.76) and OS (HR 3.68, 95% CI 1.95-6.93). Use of an alternative donor was an independent variable associated with TRM (HR 3.18, 95% CI 1.31-7.72). In conclusion, our data suggest that disease status at the time of transplant is the major predictor for improved PFS and OS, and treatments required to reach this goal may have value in leading to an improved outcome.

  17. R&D for graft adsorbents by radiation processing

    NASA Astrophysics Data System (ADS)

    Seko, Noriaki; Tamada, Masao

    Fibrous adsorbent for removal and recovery of metal ions have been synthesized by graft polymerization. In the grafting, the functional groups which have high selectivity against for target metal ions such as Fe, Sc, As, and U are introduced onto nonwoven fabric. When the monomer has a chelate group which makes selective coordination bond to specific these ions, it was directly grafted on the trunk polymer. In the case of precursor monomer having functional groups such as epoxy ring, the grafted trunk fabric is chemically modified. The resultant fibrous adsorbent leads the swift adsorption of metal ions. This property by using fibrous material can reduce the column size of adsorbent in the purification of waste water. The size of purification equipment becomes quite compact and that implies total volume of equipment can reduce. Instead of organic solvent, emulsion system which disperses monomer micelles in water with assistance of surfactant was found to accelerate the graft polymerization. This means the air pollution from organic solvent can be avoided by water system grafting. Furthermore, since the emulsion grafting was highly efficient, the required irradiation dose was considerably lower compared to general organic solvent system. As a result, the emulsion grafting has enormous potential for natural polymer to use as a trunk material for grafting. If a natural polymer such as cellulose can be used, the dependence on petroleum resources, the amount of industrial waste and the generation of carbon dioxide will be reduced to some extent.

  18. Diagnosis and differential diagnosis of hepatic graft versus host disease (GVHD)

    PubMed Central

    Matsukuma, Karen E.; Wei, Dongguang; Sun, Kai; Ramsamooj, Rajendra

    2016-01-01

    Graft versus host disease (GVHD) is a common complication following allogeneic hematopoietic cell transplantation (HCT) that typically manifests as injury to the skin, gastrointestinal mucosa, and liver. In some cases, hepatic GVHD may be histologically indistinguishable from other disorders such as infection and drug-induced liver injury (DILI). Additionally, clinical signs and symptoms are frequently confounded by the superimposed effects of pretransplant chemoradiotherapy, immunotherapy (IT) (targeted to the underlying malignancy), GVHD prophylaxis, and infection. Thus, careful attention to and correlation with clinical findings, laboratory values, and histologic features is essential for diagnosis. This review, aimed at the practicing pathologist, will discuss current clinical and histologic criteria for GVHD, the approach to diagnosis of hepatic GVHD, and features helpful for distinguishing it from other entities in the differential diagnosis. PMID:27034810

  19. Anti-fouling ultrafiltration membrane prepared from polysulfone-graft-methyl acrylate copolymers by UV-induced grafting method.

    PubMed

    Hua, Helin; Li, Na; Wu, Linlin; Zhong, Hui; Wu, Guangxial; Yuan, Zonghuan; Lin, Xiangwei; Tang, Lianyi

    2008-01-01

    Membrane fouling is one of the most important challenges faced in membrane ultrafiltration operations. The copolymers of polysulfone-graft-methyl acrylate were synthesized by homogeneous photo-initiated graft copolymerization. The variables affecting the degree of grafting, such as the time of UV (Ultraviolet-visible) irradiation and the concentrations of the methyl acrylate and photoinitiator, were investigated. The graft copolymer membranes were prepared by the phase inversion method. The chemical and morphological changes were characterized by attenuated total reflection-Fourier transform infrared spectroscopy (ATR/FT-IR), scanning electron microscopy, and water contact angles measurements. Results revealed that methyl acrylate groups were present on the membranes and the graft degree of methyl acrylate had remarkable effect on the performance of membranes. Pure water contact angle on the membrane surface decreases with the increase of methyl acrylate graft degree, which indicated that the hydrophilicity of graft copolymer membranes was improved. The permeation fluxes of pure water and bovine serum albumin solution were measured to evaluate the antifouling property of graft copolymer membranes, the results of which have shown an enhancement of antifouling property for graft copolymer membranes.

  20. Modification of polyetherurethane for biomedical application by radiation-induced grafting. I. Grafting procedure, determination of mechanical properties, and chemical modification of grafted films

    SciTech Connect

    Jansen, B.; Ellinghorst, G.

    1985-11-01

    Radiation grafting of monomers onto suitable trunk polymers is a useful tool for tailoring new polymers for special purposes. This technique has been used in the past for the development of biocompatible materials, e.g., by grafting hydrogels onto mechanically stable polymers. In this first part of our work, the radiation grafting of hydrophilic or reactive monomers onto a polyetherurethane film using the pre-swelling technique is described. Following this technique the trunk polymer was swollen in the monomer before irradiation. As monomers 2-hydroxyethyl methacrylate (HEMA), 2,3-epoxypropyl methacrylate (GMA), 2,3-dihydroxypropyl methacrylate (GOMA), and acrylamide (AAm) were used. The kinetics of the grafting reactions were examined, and the distribution of the graft component inside the trunk polymer was investigated by means of infrared (IR) spectroscopy. Surface-grafted as well as bulk- and surface-grafted products could be obtained. The mechanical behavior of the grafted films--especially in the water-swollen state--was examined and compared with that of the pure trunk polymer. In nearly all cases it was found that the tensile strength sigma B and the elongation at break epsilon R decreases as the grafting yield increases. Modification of GMA- and AAm-grafted films via chemical reactions was performed to create new functional groups of biomedical interest. In this manner a diol structure, a carboxylic acid structure, and a sulfonic acid group could be introduced in the grafted polymer. The water uptake of such modified films is increased markedly when compared with that of the unmodified samples.

  1. ACL Revision in Synthetic ACL graft failure

    PubMed Central

    Etcheto, H. Rivarola; Zordán, J.; Escobar, G.; Collazo, C.; Palanconi, M.; Autorino, C.; Salinas, E. Alvarez

    2017-01-01

    The development of synthetic grafts as an alternative to biological grafts for reconstruction of the anterior cruciate ligament dates from 1980. The interest is awakened due to the potential advantages of: The absence of morbidity associated with donor site, and early return to sport. However, this surgical technique has had multiple complications associated with graft: mechanical failures (synthetic graft failure, loss of fixation), synovial foreign body reaction, recurrent stroke, recurrent instability and ultimately, early osteoarthritis. Objectives: We describe the synthetic graft failure LCA, intraoperative findings and details of surgical technique. Methods: Patient 35 years old, with a history of ACL reconstruction four years of evolution in another health center, consultation with the Service knee arthroscopy for acute knee pain left knee during secondary sporting event to a rotation mechanism with fixed foot. On physical examination, presents and positive Lachman maneuver Pivot. Radiografia in a widening of the tibial tunnel is observed. NMR shows a discontinuity of fibers of synthetic graft. Results: First time arthroscopic revision where synthetic plastic LCA identifies with Disruption fiber pattern. Intraoperatively, hypertrophic chronic synovitis localized predominantly in intercóndilo is observed. debridement thereof is performed, and proceeds to the extraction of the synthetic ligament. Then he was made prior cruentado and revival of the edges of the tunnel, filling them with non-irradiated structural bone allograft. At four months as planned and after confirmation by studies incorporating bone graft was performed the second time with the new plastic ACL. It was planned like a primary graft surgery with autologous hamstring prepared in fourfold form, and fixation with modified transtibial technique Biotransfix system proximal and distal screw Biocomposite (arthrex®). A quadruple graft 9 mm was obtained, making good positioning of tunnels and stable

  2. Rationale and recommendations for the irradiation of blood products

    SciTech Connect

    Pritchard, S.L.; Rogers, P.C.

    1987-01-01

    Blood products are often irradiated to prevent proliferation of lymphocytes which could cause graft-vs.-host disease in immunocompromised recipients. The effects of irradiation on the function of blood components is discussed. It is concluded that 1500 rad is sufficient to prevent lymphocyte proliferation and production of graft-vs.-host disease in vivo, although 10 to 20% of lymphocytes are still capable of proliferation in vitro after 1500 rad. Neutrophils and erythrocytes are extremely radioresistant and their function is unaffected by 1500 rad. There are limited data to suggest that platelet yields may be slightly reduced following irradiation. Guidelines for the use of irradiated blood products are suggested.61 references.

  3. Pre-transplant assessment of CMV-specific immune response by Elispot assay in kidney transplant recipients.

    PubMed

    Rittà, Massimo; Costa, Cristina; Sidoti, Francesca; Ballocco, Cinzia; Ranghino, Andrea; Messina, Maria; Biancone, Luigi; Cavallo, Rossana

    2015-07-01

    Cytomegalovirus (CMV) primary infection or re-activation in solid organ transplant (SOT) recipients is associated with increased morbidity and mortality, with patients with IgG-CMV D+/R- sero-matching at greater risk. The impact of pre-transplant CMV-specific host cellular immunity on the long-term risk of CMV replication in kidney transplants (KT) was prospectively evaluated in eighty patients by CMV-EliSpot assay. The study population included 54 male and 26 female recipients, with CMV-IgG distribution: 60 D+/R+, 11 D-/R+, 7 D+/R-, 2 D-/R-. At pre-transplantation, 49 KT (61.3%) were CMV-responders by EliSpot. At 3-month follow up, 16 (32.7%) out of 49 CMV-responders showed CMV blood infection, compared to 8 (25.8%) out of 31 non-responders. No further episode of CMV viraemia was reported in the responder group, in comparison to 15 out 31 non-responders (48.4%) showing at least one episode of CMV-DNAemia at 12-month follow-up. Baseline CMV-IgG serology showed a strong correlation with EliSpot determinations; KT recipients exhibiting at least one episode of CMV viraemia at 12-month follow-up showed lower baseline CMV-EliSpot values than those without signs of CMV replication. The study suggests that monitoring CMV-specific T-cell responses at pre-transplantation by EliSpot assay may be useful for predicting the post-transplantation risk of CMV infection and reactivation.

  4. Failure to fully disclose during pretransplant psychological evaluation in alcoholic liver disease: a driving under the influence corroboration study.

    PubMed

    Bajaj, Jasmohan S; Saeian, Kia; Hafeezullah, Muhammad; Franco, Jose; Thompson, Andrea; Anderson, Rebecca

    2008-11-01

    The prevention of recidivism in alcoholic liver disease is one of the aims of pretransplant psychological evaluation (PE). Failure to fully disclose the extent of alcohol use is evidence of ongoing alcoholism. Driving under the influence (DUI) represents objective evidence of alcohol abuse, but verifying DUIs through official records is not standard during PE. The aim of this study was to determine whether there was failure to fully disclose alcohol abuse on the part of patients on the basis of the Wisconsin Department of Transportation (DOT) DUI rate. Demographics, alcohol abuse/abstinence history, and DUIs admitted by the patient on PE were collected for 82 alcoholic patients with cirrhosis. The DOT was queried for DUIs before PE for all patients. Discrepancies between PE and DOT DUI numbers were evaluated and re-presented to the psychologist without identifiers. Psychosocial recommendation was then evaluated in light of DOT/PE DUI discrepancies. Six patients did not drive. The remaining 76 had 29 +/- 8 years of alcohol abuse and reported sobriety for 55 +/- 64 months before PE. Eighteen DUIs that were not originally admitted were discovered; 63% of DUIs occurred in the period during which patients claimed to be sober. Two patients had been rejected for transplant for other causes. Re-presenting the case to the psychologist with the new knowledge of DUIs would have prevented transplant clearance for the remaining 16 (21%, P = 0.000005 versus prior PE). In conclusion, official DUI records in prospective transplant candidates may identify patients who do not fully disclose the extent of their alcohol abuse and may be at risk for adverse outcomes.

  5. Risk of end-stage renal disease among liver transplant recipients with pre-transplant renal dysfunction

    PubMed Central

    Ruebner, R; Goldberg, D; Abt, PL; Bahirwani, R; Levine, M; Sawinski, D; Bloom, RD; Reese, PP

    2012-01-01

    Guidelines recommend restricting simultaneous liver-kidney (SLK) transplant to candidates with prolonged dialysis or estimated glomerular filtration rate (eGFR) <30 ml/min/1.73m2 for 90 days. However, few studies exist to support the latter recommendation. Using SRTR and Medicare dialysis data, we assembled a cohort of 4997 liver transplant recipients from 2/27/2002–1/1/2008. Serial eGFRs were calculated from serum creatinines submitted with MELD reports. We categorized recipients by eGFR patterns in the 90 days pre-transplant: Group 1 (eGFR always >30), Group 2 (eGFR fluctuated), Group 3 (eGFR always <30) and Group 4 (short-term dialysis). For Group 2, we characterized fluctuations in renal function using time-weighted mean eGFR. Among liver-alone recipients in Group 3, the rate of end-stage renal disease (ESRD) by 3 years was 31%, versus <10% for other groups (p<0.001). In multivariable Cox regression, eGFR Group, diabetes (HR 2.65, p<0.001) and black race (HR 1.83, p=0.02) were associated with ESRD. Among liver-alone recipients in Group 2, only diabetics with time-weighted mean eGFR<30 had a substantial ESRD risk (25.6%). In summary, among liver transplant candidates not on prolonged dialysis, SLK should be considered for those whose eGFR is always <30 and diabetic candidates whose weighted mean eGFR is <30 for 90 days. PMID:22759237

  6. Calcar bone graft

    SciTech Connect

    Bargar, W.L.; Paul, H.A.; Merritt, K.; Sharkey, N.

    1986-01-01

    A canine model was developed to investigate the use of an autogeneic iliac bone graft to treat the calcar deficiency commonly found at the time of revision surgery for femoral component loosening. Five large male mixed-breed dogs had bilateral total hip arthroplasty staged at three-month intervals, and were sacrificed at six months. Prior to cementing the femoral component, an experimental calcar defect was made, and a bicortical iliac bone graft was fashioned to fill the defect. Serial roentgenograms showed the grafts had united with no resorption. Technetium-99 bone scans showed more uptake at three months than at six months in the graft region. Disulfine blue injection indicated all grafts were perfused at both three and six months. Thin section histology, fluorochromes, and microradiographs confirmed graft viability in all dogs. Semiquantitative grading of the fluorochromes indicated new bone deposition in 20%-50% of each graft at three months and 50%-80% at six months. Although the calcar bone graft was uniformly successful in this canine study, the clinical application of this technique should be evaluated by long-term results in humans.

  7. Replacement of 137Cs irradiators with x-ray irradiators.

    PubMed

    Dodd, Brian; Vetter, Richard J

    2009-02-01

    Self-shielded 137Cs irradiators have been used for many years to irradiate blood products to prevent graft vs. host disease and to irradiate cells and small animals in research. A report by the National Academy of Sciences recommends that careful consideration be given to replacement of 137Cs irradiators with x-ray irradiators. Several manufacturers and users of x-ray irradiators were contacted to determine costs of replacing and maintaining 137Cs irradiators with x-ray units and to assess users' experience with x-ray irradiators. Purchase costs of x-ray units are similar to 137Cs irradiators, but maintenance costs are significantly higher if annual service contracts are used. Performance of the two irradiator types appears to be equivalent, but in some cases x-ray irradiations may need to be performed in multiple configurations to achieve adequate uniformity in dose. No literature reports were found that evaluated the biological effectiveness of x rays vs. 137Cs gamma rays; therefore, a careful study should be conducted to determine the biological effectiveness of x rays vs. 137Cs gamma rays for biological responses relevant to transfusion medicine and immunological research. Throughput may be problematic for large transfusion medicine programs, and back-up plans may be necessary in case the x-ray unit needs to be taken out of service for extended maintenance. Disposition of a 137Cs irradiator will add to the cost of replacement with an x-ray unit, but disposal may be possible through the U.S. Department of Energy's Off-Site Source Recovery Program.

  8. Grafts in "closed" rhinoplasty.

    PubMed

    Scattolin, A; D'Ascanio, L

    2013-06-01

    Rhinoplasty is a fascinating and complex surgical procedure aiming at attaining a well-functioning and aesthetically pleasant nose. The use of grafts is of the utmost importance for the nasal surgeon to achieve such results. However, the philosophy and technical use of nasal grafts are different in "closed" and "open" rhinoplasty. The aim of this paper is not detailed description of the numerous grafts reported in the literature; we will describe the main principles of grafts use in "closed" rhinoplasty derived from our experience, with special reference to the philosophical and technical differences in their employment between "closed" and "open" rhinoplasty. Some cases are reported as an example of graft use in "endonasal" approach rhinoplasty.

  9. Effects of solvents on the radiation grafting reaction of vinyl compounds on poly (3-hydroxybutyrate)

    NASA Astrophysics Data System (ADS)

    Torres, Maykel González; Talavera, José Rogelio Rodríguez; Muñoz, Susana Vargas; Pérez, Manuel González; Castro, Ma. Pilar. Carreón.; Cortes, Jorge Cerna; Muñoz, Rodrigo Alonso Esparza

    2015-03-01

    Vinyl Acetate was grafted onto poly (3-hydroxybutyrate) by the simultaneous gamma irradiation method using different types of solvents and in bulk (solvent free), at 10 kGy and 1.62 kGy/h dose and dose rate respectively. Subsequent complete hydrolysis allowed the conversion of grafted chains from poly (vinyl acetate) to poly (vinyl alcohol). The aim of this study is to determine the effect of solvent through the estimation of the dependence of the degree of grafting with the choice of solvent, the calculation of the degree of crystallinity, and to study the biodegradation of the products. The results showed a greater degree of grafting in bulk, while the more suitable solvent was hexane. Characterization of the grafted copolymer indicated that crystallinity percentage decreased by an increase in grafting, while the biodegradability was promoted by the increment in poly (vinyl alcohol) grafted.

  10. Graft polymerization using radiation-induced peroxides and application to textile dyeing

    NASA Astrophysics Data System (ADS)

    Enomoto, Ichiro; Katsumura, Yosuke; Kudo, Hisaaki; Soeda, Shin

    2011-02-01

    To improve the dyeing affinity of ultra high molecular weight polyethylene (UHMWPE) fiber, surface treatment by radiation-induced graft polymerization was performed. Methyl methacrylate (MMA), acrylic acid (AA) and styrene (St) were used as the monomers. The grafting yields as a function of storage time after irradiation were examined. Although the grafting yield of St after the sulfonation processing was quite low compared with those of MMA and AA, it was successfully dyed to a dark color with a cationic dye. Some acid dyes can dye the grafted fiber with AA. The acid dye is distributed to the amorphous domains of the AA grafted fiber. The dyeing concentration depended on the grafting yield, and the higher the grafting yield the darker the dye color.

  11. Radiation-grafting of acrylamide onto silicone rubber films for diclofenac delivery

    NASA Astrophysics Data System (ADS)

    Magaña, Hector; Palomino, Kenia; Cornejo-Bravo, Jose M.; Alvarez-Lorenzo, Carmen; Concheiro, Angel; Bucio, Emilio

    2015-02-01

    This work focuses on the pre-irradiation grafting of acrylamide (AAm) onto silicone rubber films (SR) and evaluates the effect of gamma-ray radiation conditions on the grafting yield, which in turn may influence the performance of the grafted materials as components of drug-eluting devices. Pristine and modified SR were characterized using FTIR-ATR, DSC, TGA, swelling, and water contact angle analysis in order to elucidate the effects of AAm grafting onto SR. Grafted films with content in AAm ranging from 0.81% to 22.20% showed excellent cytocompatibility against fibroblasts, and capability to uptake the anti-inflammatory drug diclofenac. Amount of drug loaded directly correlated with the grafting degree of the films. Drug release studies were performed at pH 7.4 and 37 °C (physiological conditions). Most grafted films released the drug in a sustained way for at least three hours.

  12. Characterization of methyl methacrylate grafting onto preirradiated biodegradable lignocellulose fiber by gamma-radiation.

    PubMed

    Khan, Ferdous

    2005-01-14

    Gamma-radiation-induced graft copolymerization of methyl methacrylate onto natural lignocellulose (jute) fiber was carried out by the preirradiation method in an aqueous medium by using octylphenoxy-polyethoxyethanol as an emulsifier. The different factors that influenced the graft copolymer reaction process were investigated. In the case of radiation-dose-dependent grafting, samples irradiated in the presence of air produced up to 73% graft weight compared to 53% obtained in the case of irradiation in a nitrogen environment. By assuming Arrhenius reaction kinetics, the activation energy (E(a)) of the grafting reaction process was evaluated for different reaction temperatures. Moreover, the graft copolymer reaction was controlled by incorporating a homopolymer-inhibiting agent and three different chain-transfer agents in the reaction medium. The mechanical and thermal properties of jute fiber 'as received' and jute-graft-poly(methyl methacrylate) were also investigated. The results showed that the percentage of grafting with jute fiber has a significant effect on the properties. The kinetic parameters were evaluated from TGA thermograms by using Broido's method in the temperature range 240-350 degrees C. Scanning electron micrographs show that the structural changes on the surface of jute fibers were induced by graft copolymerization of methyl methacrylate monomer. Fiber-fiber surface friction was measured in terms of the average maximum load and the kinetic friction. SEM of jute-graft-poly(methyl methacrylate).

  13. Stearyl methacrylate-grafted-chitosan nanoparticle as a nanofiller for PLA: Radiation-induced grafting and characterization

    NASA Astrophysics Data System (ADS)

    Rattanawongwiboon, Thitirat; Haema, Kamonwon; Pasanphan, Wanvimol

    2014-01-01

    This paper reports a one-pot synthesis using radiation-induced grafting technique to modify biopolymer-based chitosan nanoparticles as a nanofiller for blending with poly(lactic acid) (PLA). Hydrophobic stearyl methacrylate (SMA) was grafted onto non-irradiated chitosan (CS0) and pre-irradiated chitosan with a γ-ray dose of 40 kGy (CS40) to obtain stearyl methacrylate-grafted-chitosan nanoparticles (SMA-g-CSNPs).The effects of the pre-irradiated CS, grafting doses and SMA concentrations on degree of grafting (DG) and particle formation were studied. FT-IR and XRD were used to characterize the chemical and packing structure of SMA-g-CSNPs. The particle formulation and size of SMA-g-CSNPs were observed by TEM and AFM. The spherical core-shell SMA-g-CSNPs with the size ranging from 50 to 140 nm were successfully prepared. The SMA-g-CSNPs from CS40 has higher DG and smaller particle size when compared with CS0. The SMA-g-CSNPs are able to improve the compatibility between CS and PLA.

  14. Bone graft substitutes.

    PubMed

    Bhatt, Reena A; Rozental, Tamara D

    2012-11-01

    Replacement of missing bone stock is a reconstructive challenge to upper extremity surgeons and decision-making with regards to available choices remains difficult. Preference is often given to autograft in the form of cancellous, cortical, or corticocancellous grafts from donor sites. However, the available volume from such donor sites is limited and fraught with potential complications. Advances in surgical management and medical research have produced a wide array of potential substances that can be used for bone graft substitute. Considerations in selecting bone grafts and substitutes include characteristic capabilities, availability, patient morbidity, immunogenicity, potential disease transmission, and cost variability.

  15. Microwave assisted synthesis of acrylamide grafted locust bean gum and its application in drug delivery.

    PubMed

    Kaity, Santanu; Isaac, Jinu; Kumar, P Mahesh; Bose, Anirbandeep; Wong, Tin Wui; Ghosh, Animesh

    2013-10-15

    Acrylamide grafted copolymer of locust bean gum was prepared by microwave irradiation using ceric ammonium nitrate as redox initiator. The grafting process was optimized in terms of irradiation time, amount of initiator and acrylamide by using constant amount of native locust bean gum. The grafted gum was characterized by Fourier transform infrared spectroscopy (FT-IR), (13)C nuclear magnetic resonance (NMR), scanning electron microscopy (SEM), X-ray diffraction study (XRD), differential scanning calorimetry (DSC), elemental analysis, contact angle, viscosity, molecular weight, swelling and biodegradability studies. The grafted gum was found to be biodegradable and non-toxic. It was further used to prepare controlled-release matrix tablet of buflomedil hydrochloride. The in vitro release profile of the tablet showed the rate controlling property of acrylamide grafted locust bean gum was similar to that of hydroxypropyl methylcellulose (HPMC-K15M).

  16. Correction of murine SCID-X1 by lentiviral gene therapy using a codon-optimized IL2RG gene and minimal pretransplant conditioning.

    PubMed

    Huston, Marshall W; van Til, Niek P; Visser, Trudi P; Arshad, Shazia; Brugman, Martijn H; Cattoglio, Claudia; Nowrouzi, Ali; Li, Yuedan; Schambach, Axel; Schmidt, Manfred; Baum, Christopher; von Kalle, Christof; Mavilio, Fulvio; Zhang, Fang; Blundell, Mike P; Thrasher, Adrian J; Verstegen, Monique M A; Wagemaker, Gerard

    2011-10-01

    Clinical trials have demonstrated the potential of ex vivo hematopoietic stem cell gene therapy to treat X-linked severe combined immunodeficiency (SCID-X1) using γ-retroviral vectors, leading to immune system functionality in the majority of treated patients without pretransplant conditioning. The success was tempered by insertional oncogenesis in a proportion of the patients. To reduce the genotoxicity risk, a self-inactivating (SIN) lentiviral vector (LV) with improved expression of a codon optimized human interleukin-2 receptor γ gene (IL2RG) cDNA (coγc), regulated by its 1.1 kb promoter region (γcPr), was compared in efficacy to the viral spleen focus forming virus (SF) and the cellular phosphoglycerate kinase (PGK) promoters. Pretransplant conditioning of Il2rg(-/-) mice resulted in long-term reconstitution of T and B lymphocytes, normalized natural antibody titers, humoral immune responses, ConA/IL-2 stimulated spleen cell proliferation, and polyclonal T-cell receptor gene rearrangements with a clear integration preference of the SF vector for proto-oncogenes, contrary to the PGK and γcPr vectors. We conclude that SIN lentiviral gene therapy using coγc driven by the γcPr or PGK promoter corrects the SCID phenotype, potentially with an improved safety profile, and that low-dose conditioning proved essential for immune competence, allowing for a reduced threshold of cell numbers required.

  17. Metabolic Serum Profiles for Patients Receiving Allogeneic Stem Cell Transplantation: The Pretransplant Profile Differs for Patients with and without Posttransplant Capillary Leak Syndrome

    PubMed Central

    Reikvam, Håkon; Grønningsæter, Ida-Sofie; Ahmed, Aymen Bushra; Hatfield, Kimberley; Bruserud, Øystein

    2015-01-01

    Allogeneic stem cell transplantation is commonly used in the treatment of younger patients with severe hematological diseases, and endothelial cells seem to be important for the development of several posttransplant complications. Capillary leak syndrome is a common early posttransplant complication where endothelial cell dysfunction probably contributes to the pathogenesis. In the present study we investigated whether the pretreatment serum metabolic profile reflects a risk of posttransplant capillary leak syndrome. We investigated the pretransplant serum levels of 766 metabolites for 80 consecutive allotransplant recipients. Patients with later capillary leak syndrome showed increased pretherapy levels of metabolites associated with endothelial dysfunction (homocitrulline, adenosine) altered renal regulation of fluid and/or electrolyte balance (betaine, methoxytyramine, and taurine) and altered vascular function (cytidine, adenosine, and methoxytyramine). Additional bioinformatical analyses showed that capillary leak syndrome was also associated with altered purine/pyrimidine metabolism (i.e., metabolites involved in vascular regulation and endothelial functions), aminoglycosylation (possibly important for endothelial cell functions), and eicosanoid metabolism (also involved in vascular regulation). Our observations are consistent with the hypothesis that the pretransplant metabolic status can be a marker for posttransplant abnormal fluid and/or electrolyte balance. PMID:26609191

  18. Surface modification of poly(styrene-b-(ethylene-co-butylene)-b-styrene) elastomer via photo-initiated graft polymerization of poly(ethylene glycol)

    NASA Astrophysics Data System (ADS)

    Li, Xiaomeng; Luan, Shifang; Yang, Huawei; Shi, Hengchong; Zhao, Jie; Jin, Jing; Yin, Jinghua; Stagnaro, Paola

    2012-01-01

    Poly(styrene-b-(ethylene-co-butylene)-b-styrene) (SEBS) copolymer biomedical elastomer was covalently grafted with poly(ethylene glycol) methyl ether methacrylate (PEGMA) via a photo-initiated graft polymerization technique. The surface graft polymerization of SEBS with PEGMA was verified by ATR-FTIR and XPS. Effect of graft polymerization parameters, i.e., monomer concentration, UV irradiation time and initiator concentration on the grafting density was investigated. Comparing with the virgin SEBS film, the PEGMA-modified SEBS film presented an enhanced wettability and a larger surface energy. Besides, the surface grafting of PEGMA imparted excellent anti-platelet adhesion and anti-protein adsorption to the SEBS surface.

  19. Total lymphoid irradiation and discordant cardiac xenografts

    SciTech Connect

    Kaplan, E.; Dresdale, A.R.; Diehl, J.T.; Katzen, N.A.; Aronovitz, M.J.; Konstam, M.A.; Payne, D.D.; Cleveland, R.J. )

    1990-01-01

    Total lymphoid irradiation can prolong concordant cardiac xenografts. The effects of total lymphoid irradiation in a discordant xenograft model (guinea pig to rat) were studied with and without adjuvant pharmacologic immunosuppression. Inbred Lewis rats were randomly allocated to one of four groups. Group 1 (n = 6) served as a control group and rats received no immunosuppression. Group 2 (n = 5) received triple-drug therapy that consisted of intraperitoneal azathioprine (2 mg/kg), cyclosporine (20 mg/kg), and methylprednisolone (1 mg/kg) for 1 week before transplantation. Group 3 animals (n = 5) received 15 Gy of total lymphoid irradiation in 12 divided doses over a 3-week period. Group 4 (n = 6) received both triple-drug therapy and total lymphoid irradiation as described for groups 2 and 3. Complement-dependent cytotoxicity assay was performed to determine if a correlation between complement-dependent cytotoxicity and rejection-free interval existed. Rejection was defined as cessation of graft pulsation and was confirmed by histologic test results. Only groups 1 and 2 showed a difference in survival (group 1, 6.9 +/- 1.0 minutes; group 2, 14.2 +/- 2.7 minutes, p = 0.02). Although total lymphoid irradiation did decrease complement-dependent cytotoxicity, linear regression revealed no correlation between complement-dependent cytotoxicity and graft survival (coefficient of correlation, 0.30). Unlike concordant cardiac xenografts, total lymphoid irradiation with or without triple-drug therapy does not prolong graft survival.

  20. Dendritic cell count in the graft predicts relapse in patients with hematologic malignancies undergoing an HLA-matched related allogeneic peripheral blood stem cell transplant.

    PubMed

    Rajasekar, Reena; Lakshmi, Kavitha M; George, Biju; Viswabandya, Auro; Thirugnanam, Rajasekar; Abraham, Aby; Chandy, Mammen; Srivastava, Alok; Mathews, Vikram

    2010-06-01

    We investigated the impact of the number of infused and reconstituted immunocompetent cells including dendritic cells (DCs) on clinical outcome of patients with hematologic malignancies undergoing an allogeneic peripheral blood stem cell transplantation. Sixty-nine consecutive patients with hematologic malignancies were included in the analysis. The median age of the cohort was 32 years (range: 2-62 years) and there were 39 (57%) males. Twenty-one (30%) patients relapsed with a cumulative incidence of 44 % +/- 14% at a median follow up of 28 months. On a multivariate analysis, a high plasmacytoid dendritic cell (PC) content in the graft was associated with higher risk of relapse. The patients were further categorized based on the median PC counts in the graft as high (> or =2.3 x 10(6)/kg) and low (<2.3 x 10(6)/kg) groups. The baseline characteristics of these 2 groups were comparable. The group that had a high PC content in the graft had significantly higher risk of relapse and lower overall survival (OS) and event-free survival (EFS). Our data suggests that PC content in the graft predicts clinical outcomes such as relapse and survival in patients with hematologic malignancies undergoing an allogeneic HLA matched related peripheral blood stem cell transplantation. There is potential for pretransplant manipulation of this cellular subset in the graft.

  1. Swelling, ion uptake and biodegradation studies of PE film modified through radiation induced graft copolymerization

    NASA Astrophysics Data System (ADS)

    Kaur, Inderjeet; Gupta, Nitika; Kumari, Vandna

    2011-09-01

    An attempt to develop biodegradable polyethylene film grafting of mixture of hydrophilic monomers methacrylic acid (MAAc) and acrylamide (AAm) onto PE film has been carried out by preirradiation method using benzoyl peroxide as the radical initiator. Since ether linkages are susceptible to easy cleavage during degradation process, PE film was irradiated before the grafting reactions by γ-rays to introduce peroxidic linkages (PE-OO-PE) that offer sites for grafting. The effect of irradiation dose, monomer concentration, initiator concentration, temperature, time and amount of water on the grafting percent was determined. Maximum percentage of grafting of binary mixture (MAAc+AAm), (1792%) was obtained at a total concentration of binary monomer mixture=204.6×10 -2 mol/L ([MAAc]=176.5×10 -2 mol/L, [AAm]=28.1×10 -2 mol/L), [BPO]=8.3×10 -2 mol/L at 100 °C in 70 min. The grafted PE film was characterized by the Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA) and Scanning Electron Microscopic (SEM) methods. Some selective properties of grafted films such as swelling studies, ion uptake and biodegradation studies have been investigated. The grafted films show good swelling in water, ion uptake studies shows promising results for desalination of brackish water and the soil burial test shows that PE film grafted with binary monomer mixture degrades up to 47% within 50 days.

  2. Study on biotribological properties of UHMWPE grafted with MPDSAH.

    PubMed

    Deng, Yaling; Xiong, Dangsheng; Shao, Silong

    2013-04-01

    In order to prolong the service life of artificial joints, a zwitterion monomer of MPDSAH ((3-(methacryloylamino)propyl)dimethyl (3-sulfopropyl)ammonium hydroxide) was grafted onto ultra-high molecular weight polyethylene (UHMWPE) powders to construct a brush-like structure by UV irradiation, and then the grafted UHMWPE powders were hot pressed as the bulk materials. The wettability of bulk materials surface with different monomer concentrations was analyzed. The tribological properties of modified UHMWPE bulk materials were investigated under distilled water and saline by sliding against stainless steel ball. The measurement of Fourier-transform infrared (FT-IR) spectroscopy indicates that MPDSAH is successfully grafted onto the surface of UHMWPE powders by UV irradiation. The contact angles of modified UHMWPE are decreased and the surface wettability is effectively improved. The friction coefficient of the modified sample is lower than that of untreated UHMWPE in aqueous lubricants during a long-term friction. With the increase of monomer concentration, the wear rate of grafted UHMWPE decreases gradually in distilled water. The grafting hydrophilic macromolecule polymer is helpful to form a lubricating film of water, which leads to the improvement of the lubricity of UHMWPE.

  3. Grafting in revision rhinoplasty.

    PubMed

    Bussi, M; Palonta, F; Toma, S

    2013-06-01

    Rhinoplasty is one of the most difficult aesthetic surgery procedures with a high rate of revision. In revision rhinoplasty the surgeon should explore the patient's concerns and then verify the possibility to satisfy expectations after complete internal and external examination of the nose. For the vast majority of complex secondaries, an open approach is the only reasonable method. In fact, in secondary nasal surgery, because of the scarring process following the primary operation, dissection is tedious, and landmarks are lost. One of the main objectives for the surgeon who approaches secondary rhinoplasty is to restore the structural support of the nose and to replace the lost volume of soft tissues. To achieve this purpose, the surgeon must often rely on grafts. An ideal grafting material must be easy to sculpt, resistant to trauma, infection and extrusion, mechanically stable, inert and readily available. For all these reasons, autogenous cartilage grafts harvested from septum, auricular concha and rib represent the first choice in rhinoplasty. In order to obtain a camouflage graft that provides natural contouring to the nose, temporalis fascia can be used. All these carefully trimmed grafts are useful in tip revision surgery, in secondary surgery of the dorsum and to resolve or reduce functional problems.

  4. Graft versus host anti-Rho(D) following minor Rh-incompatible orthotopic liver transplantation.

    PubMed

    Lee, J H; Mintz, P D

    1993-11-01

    Hemolysis caused by ABO antibodies after ABO-compatible, nonidentical solid organ transplantation has been previously reported. The passenger B lymphocytes within the donor organ presumably generate an acute, primarily red cell-directed graft vs. host (GVH) response. Graft survival may also be compromised. GVH Rh antibodies have also been described, primarily in renal transplants. Only three cases, two only in abstract form, have been reported thus far describing GVH Rh antibodies in liver transplant patients, to which we add a fourth. A 62-year-old blood group A Rho(D)-positive woman with cirrhosis underwent orthotopic liver transplantation from a group A Rho(D)-negative, previously Rho(D)-sensitized donor and subsequently developed acute, self-limited hemolysis requiring four units of packed red cells. Anti-Rho(D) was identified in both serum and red cell eluate. An antibody detection test, identification, and assessment of the antibody reactivity score from the pretransplant donor specimen may identify patients at risk for hemolysis due to GVH Rh antibodies.

  5. The role of hydroperoxides as a precursor in the radiation-induced graft polymerization of methyl methacrylate to ultra-high molecular weight polyethylene

    NASA Astrophysics Data System (ADS)

    Enomoto, Ichiro; Katsumura, Yosuke; Kudo, Hisaaki; Sekiguchi, Masayuki

    2010-06-01

    A graft polymerization of methyl methacrylate (MMA) to ultra-high molecular weight polyethylene (UHMWPE) with Co-60 γ-ray irradiation in air at room temperature has been carried out. The grafting yields were measured as a function of the storage time (elapsed time from the end of irradiation to the start of grafting), and it was found that the yields reach at the maximum values at around several days since the end of irradiation. In order to clarify the precursor of the graft polymerization, changes of the radical yields and the carbonyl groups were measured as a function of storage time with ESR and microscopic FT-IR, respectively. From the similarities between the depth profiles of the hydroperoxide formation and the grafting products, it was concluded that the hydroperoxides can be main precursors of the grafting of the radiation-induced polymerization of MMA to UHMWPE under the given conditions.

  6. Photoinduced Graft-Polymerization of Acrylic Acid on Polyethylene and Polypropylene Surfaces: Comparative Study Using IR-ATR Spectroscopy

    NASA Astrophysics Data System (ADS)

    Gorbachev, A. A.; Tretinnikov, O. N.; Shkrabatovskaya, L. V.; Prikhodchenko, L. K.

    2014-11-01

    Photoinduced graft-polymerization of acrylic acid on the surface of polyethylene and polypropylene films containing a photoinitiator pre-adsorbed from a thin layer of non-de-aerated aqueous monomer solution was investigated. Data about the monomer conversion and grafting depth as functions of the UV irradiation time and polymer nature were obtained using IR-ATR spectroscopy.

  7. Independent Pre-Transplant Recipient Cancer Risk Factors after Kidney Transplantation and the Utility of G-Chart Analysis for Clinical Process Control

    PubMed Central

    Kurok, Marlene; Goldis, Alon; Dreier, Maren; Kaltenborn, Alexander; Gwinner, Wilfried; Barthold, Marc; Liebeneiner, Jan; Winny, Markus; Klempnauer, Jürgen; Kleine, Moritz

    2016-01-01

    Background The aim of this study is to identify independent pre-transplant cancer risk factors after kidney transplantation and to assess the utility of G-chart analysis for clinical process control. This may contribute to the improvement of cancer surveillance processes in individual transplant centers. Patients and Methods 1655 patients after kidney transplantation at our institution with a total of 9,425 person-years of follow-up were compared retrospectively to the general German population using site-specific standardized-incidence-ratios (SIRs) of observed malignancies. Risk-adjusted multivariable Cox regression was used to identify independent pre-transplant cancer risk factors. G-chart analysis was applied to determine relevant differences in the frequency of cancer occurrences. Results Cancer incidence rates were almost three times higher as compared to the matched general population (SIR = 2.75; 95%-CI: 2.33–3.21). Significantly increased SIRs were observed for renal cell carcinoma (SIR = 22.46), post-transplant lymphoproliferative disorder (SIR = 8.36), prostate cancer (SIR = 2.22), bladder cancer (SIR = 3.24), thyroid cancer (SIR = 10.13) and melanoma (SIR = 3.08). Independent pre-transplant risk factors for cancer-free survival were age <52.3 years (p = 0.007, Hazard ratio (HR): 0.82), age >62.6 years (p = 0.001, HR: 1.29), polycystic kidney disease other than autosomal dominant polycystic kidney disease (ADPKD) (p = 0.001, HR: 0.68), high body mass index in kg/m2 (p<0.001, HR: 1.04), ADPKD (p = 0.008, HR: 1.26) and diabetic nephropathy (p = 0.004, HR = 1.51). G-chart analysis identified relevant changes in the detection rates of cancer during aftercare with no significant relation to identified risk factors for cancer-free survival (p<0.05). Conclusions Risk-adapted cancer surveillance combined with prospective G-chart analysis likely improves cancer surveillance schemes by adapting processes to identified risk factors and by using G-chart alarm

  8. Grafts for Ridge Preservation

    PubMed Central

    Jamjoom, Amal; Cohen, Robert E.

    2015-01-01

    Alveolar ridge bone resorption is a biologic phenomenon that occurs following tooth extraction and cannot be prevented. This paper reviews the vertical and horizontal ridge dimensional changes that are associated with tooth extraction. It also provides an overview of the advantages of ridge preservation as well as grafting materials. A Medline search among English language papers was performed in March 2015 using alveolar ridge preservation, ridge augmentation, and various graft types as search terms. Additional papers were considered following the preliminary review of the initial search that were relevant to alveolar ridge preservation. The literature suggests that ridge preservation methods and augmentation techniques are available to minimize and restore available bone. Numerous grafting materials, such as autografts, allografts, xenografts, and alloplasts, currently are used for ridge preservation. Other materials, such as growth factors, also can be used to enhance biologic outcome. PMID:26262646

  9. Urinary CD133+ Extracellular Vesicles Are Decreased in Kidney Transplanted Patients with Slow Graft Function and Vascular Damage

    PubMed Central

    Dimuccio, Veronica; Ranghino, Andrea; Praticò Barbato, Loredana; Fop, Fabrizio; Biancone, Luigi; Camussi, Giovanni; Bussolati, Benedetta

    2014-01-01

    Extracellular vesicles (EVs) present in the urine are mainly released from cells of the nephron and can therefore provide information on kidney function. We here evaluated the presence of vesicles expressing the progenitor marker CD133 in the urine of normal subjects and of patients undergoing renal transplant. We found that EV expressing CD133 were present in the urine of normal subjects, but not of patients with end stage renal disease. The first day after transplant, urinary CD133+ EVs were present at low levels, to increase thereafter (at day 7). Urinary CD133+ EVs significantly increased in patients with slow graft function in respect to those with early graft function. In patients with a severe pre-transplant vascular damage of the graft, CD133+ EVs did not increase at day 7. At variance, the levels of EVs expressing the renal exosomal marker CD24 did not vary in the urine of patients with end stage renal disease or in transplanted patients in respect to controls. Sorted CD133+ EVs were found to express glomerular and proximal tubular markers. These data indicate that urinary CD133+ EVs are continuously released during the homeostatic turnover of the nephron and may provide information on its function or regenerative potential. PMID:25100147

  10. Radiation induced graft copolymerization of methyl methacrylate onto chrome-tanned pig skins

    NASA Astrophysics Data System (ADS)

    Pietrucha, K.; Pȩkala, W.; Kroh, J.

    Graft copolymerization of methyl methacrylate (MMA) onto chrome-tanned pig skins was carried out by the irradiation with 60Co ?-rays. The grafted polymethyl methacrylate (PMMA) chains were isolated by acid hydrolysis of the collagen backbone in order to characterize the graft copolymers. Proof of grafting was obtained through the detection of amino acid endgroups in the isolated grafts by reaction with ninhydrin. The grafting yield of MMA in aqueous emulsion was found to be higher than that for pure MMA and MMA in acetone. The degree of grafting increases with increasing monomer concentration in emulsion and reaches maximum at radiation dose ca 15 kGy. The yield of grafting is very high - ca 90% of monomer converts into copolymer and only 10% is converted into homopolymer. The present paper reports the physical properties of chrome-tanned pig skins after graft polymerization with MMA in emulsion. Modified leathers are more resistant against water absorption and abrasion in comparison with unmodified ones. They have more uniform structure over the whole surface, greater thickness and stiffness. The results reported seem to indicate that MMA may be used in the production of shoe upper and sole leathers. The mechanism of some of the processes occuring during radiation grafting of MMA in water emulsion on tanned leathers has been also suggested and discussed.

  11. Graft-versus-host disease

    MedlinePlus

    GVHD; Bone marrow transplant - graft-versus-host disease; Stem cell transplant - graft-versus-host disease; Allogeneic transplant - ... GVHD may occur after a bone marrow, or stem cell, transplant in which someone receives bone marrow ...

  12. Radiation grafting of methyl methacrylate monomer on natural rubber latex. [Gamma radiation

    SciTech Connect

    Sundardi, F.; Kadariah, S.

    1984-05-01

    A method of radiation grafting of methyl methacrylate (MMA) monomer on natural rubber (NR) latex has been studied. The irradiation dose in radiation emulsion polymerization of MMA monomer was lower compared to the irradiation dose for grafting of MMA monomer on NR latex, in order to obtain the same degree of conversion. This is due to the size of the rubber particles which are quite large and, hence, not sufficient to ensure an ideal emulsion polymerization. The irradiation dose for radiation grafting of MMA monomer on latex was around 300 krad to obtain a 75% degree of conversion. However, this irradiation dose was lower compared to the irradiation dose for bulk polymerization of MMA momomer, in order to obtain the same degree of conversion. This is due to the gel effect in the viscous media. Radiation grafting of MMA monomer on NR latex does not influence the pH of the latex, but influences the viscosity significantly. The viscosity of the NR latex increased with an increase in irradiation dose, due to the increase of the total solid content in the latex. The MMA monomer converted to P-MMA in NR latex was largely grafted on the NR, or at least insoluble in a solvent for P-MMA, such as acetone or toluene. The hardness of the pure gum vulcanizate increased with an increase in the degree of grafting or P-MMA content, but the other physical properties, such as tensile strength, modulus, elongation at break, and thermal stability, were not greatly influenced by the degree of grafting. 9 references, 3 figures, 5 tables.

  13. Bone Grafts in Craniofacial Surgery

    PubMed Central

    Elsalanty, Mohammed E.; Genecov, David G.

    2009-01-01

    Reconstruction of cranial and maxillofacial defects is a challenging task. The standard reconstruction method has been bone grafting. In this review, we shall describe the biological principles of bone graft healing, as pertinent to craniofacial reconstruction. Different types and sources of bone grafts will be discussed, as well as new methods of bone defect reconstruction. PMID:22110806

  14. Grafting effects on vegetable quality

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the United States, vegetable grafting is rare and few experiments have been done to determine optimal grafting procedures and production practices for different geographical and climatic regions in America. Grafting vegetables to control soilborne disease is a common practice in Asia, parts of E...

  15. Accelerated adhesion of grafted skins by laser-induced stress wave-based gene transfer of hepatocyte growth factor

    NASA Astrophysics Data System (ADS)

    Aizawa, Kazuya; Sato, Shunichi; Saitoh, Daizoh; Tsuda, Hitoshi; Ashida, Hiroshi; Obara, Minoru

    2009-02-01

    In our previous study, we delivered plasmid DNA coding for human hepatocyto growth factor (hHGF) to rat skin grafts based on laser-induced stress wave (LISW), by which production of CD31-positive cells in the grafted skins was found to be enhanced, suggesting improved angiogenesis. In this study, we validated the efficacy of this method to accelerate adhesion of grafted skins; reperfusion and reepithelialization in the grafted skins were examined. As a graft, dorsal skin of a rat was exsected and its subcutaneous fat was removed. Plasmid DNA expression vector for hHGF was injected into the graft; on its back surface a laser target with a transparent sheet for plasma confinement was placed, and irradiated with three nanosecond laser pulses at a laser fluence of 1.2 J/cm2 (532 nm; spot diameter, 3 mm) to generate LISWs. After the application of LISWs, the graft was transplanted onto its donor site. We evaluated blood flow by laser Doppler imaging and analyzed reepithelialization based on immunohistochemistry as a function of postgrafting time. It was found that both reperfusion and reepithelialization were significantly enhanced for the grafts with gene transfection than for normal grafts; reepithelialization was completed within 7 days after transplantation with the transfected grafts. These findings demonstrate that adhesion of grafted skins can be accelerated by delivering HGF gene to the grafts based on LISWs.

  16. Skin graft - slideshow

    MedlinePlus

    ... anatomy URL of this page: //medlineplus.gov/ency/presentations/100100.htm Skin graft - series—Normal anatomy To use the sharing features on this page, please enable JavaScript. Go to slide 1 out of 4 Go to slide 2 ...

  17. Acrylonitrile grafted to PVDF

    SciTech Connect

    Yang, Jin; Eitouni, Hany Basam

    2015-03-31

    PVDF-g-PAN has been synthesized by grafting polyacrylonitrile onto polyvinylidene fluoride using an ATRP/AGET method. The novel polymer is ionically conducive and has much more flexibility than PVDF alone, making it especially useful either as a binder in battery cell electrodes or as a polymer electrolyte in a battery cell.

  18. Grafting for disease resistance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The primary purpose of grafting vegetables worldwide has been to provide resistance to soilborne diseases. The potential loss of methyl bromide as a soil fumigant combined with pathogen resistance to commonly used pesticides will make resistance to soil born pathogens even more important in the futu...

  19. Grafting for disease resistance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The primary purpose of grafting vegetables worldwide has been to provide resistance to soil-borne diseases. The potential loss of methyl bromide as a soil fumigant combined with pathogen resistance to commonly used pesticides will make resistance to soil-borne pathogens even more important in the fu...

  20. The versatile autogenous rib graft in septorhinoplasty.

    PubMed

    Sherris, D A; Kern, E B

    1998-01-01

    In the graft depleted revision rhinoplasty patient and the patient with major tissue needs, alternatives to septal and conchal cartilage grafts are needed. The costal cartilage graft and rib bone/costal cartilage combination graft are excellent alternatives. In this study 14 patients received 40 grafts from 20 autogenous ribs harvested during septorhinoplasty. Materials were harvested for use as septal replacement grafts, cantilevered grafts, dorsal onlay grafts, columellar struts, and tip grafts. Patient followup was 6 to 31 months, and no evidence of graft resorption or warpage was evident during that period. Complications of harvest were minimal, and harvest techniques are detailed.

  1. Bone Graft Substitution and Augmentation.

    PubMed

    Nauth, Aaron; Lane, Joseph; Watson, J Tracy; Giannoudis, Peter

    2015-12-01

    Selection of appropriate bone graft or bone graft substitute requires careful recognition of the bone healing needs of the patient's specific clinical problem and a thorough understanding of the different properties possessed by the available bone grafts and substitutes. Although autogenous iliac crest bone graft remains the gold standard of treatment for delayed unions, nonunions, and bone defects, there are a number of promising alternatives available, and emerging evidence suggests that they can be very effective when used in the proper setting. Among these, reamer-irrigator-aspirator bone graft, bone marrow concentrate, bone morphogenetic proteins, and calcium phosphate cements have received a great deal of attention in the literature. This review describes these grafts in detail along with the evidence for their use. In addition, a framework is provided for selecting the appropriate graft or substitute based on their provided properties.

  2. Radiation-induced and RAFT-mediated grafting of poly(hydroxyethyl methacrylate) (PHEMA) from cellulose surfaces

    NASA Astrophysics Data System (ADS)

    Kodama, Yasko; Barsbay, Murat; Güven, Olgun

    2014-01-01

    This paper presents the results of RAFT mediated free-radical graft copolymerization of 2-hydroxyethyl methacrylate (HEMA) onto cellulose fibers in a "grafting-from" approach under γ-irradiation. The effects of absorbed dose and monomer concentration on the graft ratios were investigated at different monomer (HEMA) to RAFT agent (cumyl dithiobenzoate, CDB) ratios. Cellulose-g-PHEMA copolymers with various graft ratios up to 92% (w/w) have been synthesized. The synthesized copolymers were characterized by ATR-FTIR spectroscopy, X-ray photoelectron spectroscopy, elemental analysis and scanning electron microscopy. The results of various techniques confirmed the existence of PHEMA in the copolymer composition.

  3. Singly and binary grafted poly(vinyl chloride) urinary catheters that elute ciprofloxacin and prevent bacteria adhesion.

    PubMed

    Islas, Luisa; Alvarez-Lorenzo, Carmen; Magariños, Beatriz; Concheiro, Angel; del Castillo, Luis Felipe; Burillo, Guillermina

    2015-07-05

    Acrylic acid (AAc) and poly(ethylene glycol) methacrylate (PEGMA) were singly and dually grafted onto poly(vinyl chloride) (PVC) urinary catheters with the aim of preventing biofouling by endowing the catheters with the ability to load and release antimicrobial agents and to avoid bacteria adhesion. The polymers were grafted applying an oxidative pre-irradiation ((60)Co source) method in two steps. Grafting percentage and kinetics were evaluated by varying the absorbed pre-irradiation dose, reaction time, monomer concentration, and reaction temperature. Catheters with grafting percentages ranging from 8 to 207% were characterized regarding thermal stability, surface hydrophilicity, mechanical properties, swelling, and lubricity. The modified catheters proved to have better compatibility with fibroblast cells than PVC after long exposure times. Furthermore, grafted catheters were able to load ciprofloxacin and sustained its release in urine medium for several hours. Ciprofloxacin-loaded catheters inhibited the growth of Escherichia coli and Staphylococcus aureus in the catheter surroundings and prevented bacteria adhesion.

  4. Radiation grafting of acrylic and methacrylic acid to cellulose fibers to impart high water sorbency

    SciTech Connect

    Zahran, A.H.; Williams, J.L.; Stannett, V.T.

    1980-04-01

    Acrylic and methacrylic acids have been directly grafted to rayon and cotton using the preirradiation technique with /sup 60/ Co gamma rays. The rate of grafting increased with increasing temperature and monomer concentration, as did the final degree of grafting. The amount and rate of grafting also increased with the total irradiation dose but tended to level off at higher doses, in agreement with the leveling off of the radical content reported previously. Methacrylic acid grafted more and faster than acrylic acid to both rayon and cotton. Methacrylic acid grafted more with rayon than cotton, but acrylic acid gave somewhat similar yields with both fibers. The water abosrbency of the grafted fibers depended strongly on their posttreatment. Decrystallizing with 70% zinc chloride or with hot sodium hydroxidy developed supersorbency. The two treatments in succession, respectively, gave the highest values. Metacrylic acid brought about less sorbency than the corrsponding acrylic acid grafts. Useful levels of grafting and supersorbency could be readily and practically achieved by the methods described.

  5. Radiation-induced graft polymerization of amphiphilic monomers with different polymerization characteristics onto hydrophobic polysilane

    NASA Astrophysics Data System (ADS)

    Tanaka, Hidenori; Iwasaki, Isao; Kunai, Yuichiro; Sato, Nobuhiro; Matsuyama, Tomochika

    2011-08-01

    The structures of poly(methyl-n-propylsilane) (PMPrS) amphiphilically modified through γ-ray-induced graft polymerization were investigated with 1H NMR measurement. By the use of methyl methacrylate (MMA) or diethyl fumarate (DEF) as monomers for the graft polymerization, grafting yield rose with increasing total absorption dose and monomer concentrations, but decreased with increasing dose rate. This result means that grafting yield of modified PMPrS can be controlled by changing irradiation conditions. However, the number of PMMA or PDEF graft chains per PMPrS chain was estimated to be less than 1.0 by analysis of 1H NMR spectra, and this value was lower than that we had expected. To improve graft density, maleic anhydride (MAH), which is known as a non-homopolymerizable monomer in radical polymerization, was used as a monomer for grafting. As a result, high density grafting (one MAH unit for 4.2 silicon atoms) was attained. It demonstrates that the structure of γ-ray-modified polysilane strongly depends on the polymerization characteristics of grafted monomers.

  6. Protein absorption and fouling on poly(acrylic acid)-graft-polypropylene microfiltration membrane

    NASA Astrophysics Data System (ADS)

    Liu, Yanjun; Ma, Huiying; Lv, Chunying; Yang, Jia; Fu, Xueqi

    2009-07-01

    A series of pH-sensitive poly (acrylic acid)-graft-polypropylene hollow fiber microfiltration membranes were prepared by UV-photo-irradiation. Bovine serum albumin (BSA) was chosen as the model protein to investigate its absorption and fouling behaviors on membranes. The results showed that the hydrophilicity of grafted membrane was improved by poly(acrylic acid) chains with parts of membrane pores blocked. The grafted membranes were markedly pH-dependent on the water permeability as pH was altered from 1 to 11. The zeta potential of grafted membranes calculated by streaming potential was negative in most pH range. Electrostatic interaction energy calculated by DLVO theory showed the electric interaction force between grafted membrane and BSA was attractive. With the rise of grafting degree, the electric attractive force between grafted membrane and BSA increased as pH=3 and decreased as pH=8, while it kept basically unchanged as pH=4.7. As a result, most serious fouling was observed as pH=4.7. Grafted membranes had a lower BSA absorption and better antifouling behavior as pH=8, while the opposite result was revealed as pH=3. In conclusion, the absorption and fouling behavior of BSA on membranes was pH-dependent due to the pH-dependence of membrane charge, and the conformation of BSA and grafting chains.

  7. Corneal grafting and banking.

    PubMed

    Ehlers, Niels; Hjortdal, Jesper; Nielsen, Kim

    2009-01-01

    Corneal transplantation was conceptualized at the end of the 18th century, but it took more than 100 years before human corneal grafting was introduced. The greatest step forward was the demonstration by Filatov that corneal tissue can be collected and used post mortem. The history of eye banking includes the development of preservation techniques. Storage in cold to minimize microbial growth and tissue disintegration was first choice but during the last 30 years this has been taken over by warm storage (organ culture) where the donor cornea proves its sterility and vitality before being transferred to the recipient. The long-term organ culture storage makes exchange between centres possible and allows for histocompatibility matching. The internationalization led to the establishing of the European Eye Bank Association but also to an increasing number of governmental regulations. Developments in years to come may lead to control of graft biomechanics and optics. This technical development tends to favour a centralization.

  8. [Grafting of carotid arteries].

    PubMed

    Belov, Iu V; Stepanenko, A B; Gens, A P; Bazylev, V V; Seleznev, M N; Savichev, D D

    2005-01-01

    Over 5-years, 167 reconstructive surgeries for stenosis of internal carotid arteries (ICA) were performed in 124 patients. Mean age of the patients was 63.5 years. One hundred and twenty-nine carotid endarterectomies (CEAE) in 86 patients and 38 reconstructive operations of ICA in 38 patients were performed. There were no lethal outcomes in short- and long-term postoperative period. In short-term period after prosthesis of ICA restenosis was revealed in 3% patients, after eversion CEAE in 3% patients the embolism was seen, after standard CEAE restenosis were diagnosed in 8% patients and thrombosis -- in 3%. In long-term period after grafting of ICA the strokes were seen in 3%, stenosis -- in 6% patients, after eversion endarterectomy -- in 0 and 3% patients, and after standard CEAE -- in 3 and 24% patients, respectively. It is concluded that grafting of ICA is adequate surgical method of reconstruction and stroke prevention in specific variants of carotid atherosclerosis.

  9. Grafting of acrylic acid on etched latent tracks induced by swift heavy ions on polypropylene films

    NASA Astrophysics Data System (ADS)

    Mazzei, R.; Fernández, A.; García Bermúdez, G.; Torres, A.; Gutierrez, M. C.; Magni, M.; Celma, G.; Tadey, D.

    2008-06-01

    In order to continue with a systematic study that include different polymers and monomers, the residual active sites produced by heavy ion beams, that remain after the etching process, were used to start the grafting process. To produce tracks, foils of polypropylene (PP) were irradiated with 208Pb of 25.62 MeV/n. Then, these were etched and grafted with acrylic acid (AA) monomers. Experimental curves of grafting yield as a function of grafting time with the etching time as a parameter were measured. Also, the grating yield as a function of the fluence and etching time was obtained. In addition, the permeation of solutions, with different pH, through PP grafted foils was measured.

  10. Radiation-induced graft polymerization of chitosan onto poly(3-hydroxybutyrate).

    PubMed

    Torres, Maykel González; Muñoz, Susana Vargas; Rosales, Silvia G Solís; Carreón-Castro, Ma del Pilar; Muñoz, Rodrigo Alonso Esparza; González, Roberto Olayo; González, Miriam Rocío Estévez; Talavera, Rogelio Rodríguez

    2015-11-20

    Chitosan is among the most studied biopolymers and offers important advantages, such as biodegradability, biocompatibility and nontoxicity. In this study, this polysaccharide was grafted onto poly(3-hydroxybutyrate) using the simultaneous gamma-irradiation-initiated polymerization method. The polyester was immersed in diverse solvents, which allowed the preparation of graft copolymers with different yields and crystallinities. A successful synthesis and the estimation of the degree of crystallinity were verified by spectroscopic and calorimetric techniques. The most suitable method was found to be the thermoanalytical approach because it displayed a linear relationship between the degree of crystallinity and the increasing degree of grafting. The results also indicated that the lowest degree of grafting was seen for acetic acid (14.27%), while the highest degree corresponded to ethyl acetate (32.11%). The mechanism of grafting was proposed on the basis of the experimental results.

  11. Dacron Graft Aneurysm Treated by Endovascular Stent-Graft

    SciTech Connect

    Ofer, Amos; Nitecki, Samy; Hoffman, Aaron; Engel, Ahuva

    2001-01-15

    A 72-year old man who underwent aorto-bifemoral bypass with insertion of a Dacron graft 18 years previously presented with an aneurysm in the left limb of his graft. Angiography also demonstrated a bilateral occlusion of the popliteal arteries. Computed tomography (CT) angiography was performed and showed a localized dilation of 3 cm in the left limb of the graft, which had a diameter of 14 mm throughout. In view of the technical difficulties of a surgical procedure, an endovascular stent was considered. Through a left femoral arteriotomy, a stent graft was inserted and deployed in the left limb of the graft. This resulted in total exclusion of the Dacron graft aneurysm. To the best of our knowledge, this is the first report of such a procedure.

  12. Siloxane-grafted membranes

    DOEpatents

    Friesen, D.T.; Obligin, A.S.

    1989-10-31

    Composite cellulosic semipermeable membranes are disclosed which are the covalently bonded reaction product of an asymmetric cellulosic semipermeable membrane and a polysiloxane containing reactive functional group. The two reactants chemically bond by ether, ester, amide or acrylate linkages to form a siloxane-grafted cellulosic membrane having superior selectivity and flux stability. Selectivity may be enhanced by wetting the surface with a swelling agent such as water.

  13. Siloxane-grafted membranes

    DOEpatents

    Friesen, Dwayne T.; Obligin, Alan S.

    1989-01-01

    Composite cellulosic semipermeable membranes are disclosed which are the covalently bonded reaction product of an asymmetric cellulosic semipermeable membrane and a polysiloxane containing reactive functional groups. The two reactants chemically bond by ether, ester, amide or acrylate linkages to form a siloxane-grafted cellulosic membrane having superior selectivity and flux stability. Selectivity may be enhanced by wetting the surface with a swelling agent such as water.

  14. Radiation-induced graft polymerization of acrylamide and acrylic acid onto polyethylene

    NASA Astrophysics Data System (ADS)

    Grushevskaya, L. N.; Aliev, R. E.; Kabanov, V. Ya.

    The radiation-induced grafting of acrylamide onto low-density polyethylene by the different methods and under different conditions was investigated: by the direct liquid phase method from this monomer solution in water (in neutral and acid media) and acetone, and by the pre-irradiation method from aqueous solutions as well as from its sublimated vapour. The molecular masses of polyacrylamide homopolymers were determined. The discussion and comparison of different methods of acrylamide grafting are performed. The relationship between rates of graft polymerization onto polyethylene and homopolymerization of acrylic acid in the presence of metal ions is considered.

  15. [Food irradiation].

    PubMed

    Migdał, W

    1995-01-01

    A worldwide standard on food irradiation was adopted in 1983 by Codex Alimentarius Commission of the Joint Food Standard Programme of the Food and Agriculture Organization (FAO) of the United Nations and the World Health Organization (WHO). As a result, 41 countries have approved the use of irradiation for treating one or more food items and the number is increasing. Generally, irradiation is used to: food loses, food spoilage, disinfestation, safety and hygiene. The number of countries which use irradiation for processing food for commercial purposes has been increasing steadily from 19 in 1987 to 33 today. In the frames of the national programme on the application of irradiation for food preservation and hygienization an experimental plant for electron beam processing has been established in Institute of Nuclear Chemistry and Technology. The plant is equipped with a small research accelerator Pilot (19MeV, 1 kW) and an industrial unit Elektronika (10MeV, 10 kW). On the basis of the research there were performed at different scientific institutions in Poland, health authorities have issued permission for irradiation for: spices, garlic, onions, mushrooms, potatoes, dry mushrooms and vegetables.

  16. Tissue irradiator

    DOEpatents

    Hungate, F.P.; Riemath, W.F.; Bunnell, L.R.

    1975-12-16

    A tissue irradiator is provided for the in-vivo irradiation of body tissue. The irradiator comprises a radiation source material contained and completely encapsulated within vitreous carbon. An embodiment for use as an in- vivo blood irradiator comprises a cylindrical body having an axial bore therethrough. A radioisotope is contained within a first portion of vitreous carbon cylindrically surrounding the axial bore, and a containment portion of vitreous carbon surrounds the radioisotope containing portion, the two portions of vitreous carbon being integrally formed as a single unit. Connecting means are provided at each end of the cylindrical body to permit connections to blood- carrying vessels and to provide for passage of blood through the bore. In a preferred embodiment, the radioisotope is thulium-170 which is present in the irradiator in the form of thulium oxide. A method of producing the preferred blood irradiator is also provided, whereby nonradioactive thulium-169 is dispersed within a polyfurfuryl alcohol resin which is carbonized and fired to form the integral vitreous carbon body and the device is activated by neutron bombardment of the thulium-169 to produce the beta-emitting thulium-170.

  17. Poly(2-methacryloyloxyethyl phosphorylcholine) grafting and vitamin E blending for high wear resistance and oxidative stability of orthopedic bearings.

    PubMed

    Kyomoto, Masayuki; Moro, Toru; Yamane, Shihori; Watanabe, Kenichi; Hashimoto, Masami; Takatori, Yoshio; Tanaka, Sakae; Ishihara, Kazuhiko

    2014-08-01

    The ultimate goal in manipulating the surface and substrate of a cross-linked polyethylene (CLPE) liner is to obtain not only high wear resistance but also high oxidative stability and high-mechanical properties for life-long orthopedic bearings. We have demonstrated the fabrication of highly hydrophilic and lubricious poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) grafting layer onto the antioxidant vitamin E-blended CLPE (HD-CLPE(VE)) surface. The PMPC grafting layer with a thickness of 100 nm was successfully fabricated on the vitamin E-blended CLPE surface by using photoinduced-radical graft polymerization. Since PMPC has a highly hydrophilic nature, the water wettability and lubricity of the PMPC-grafted CLPE and HD-CLPE(VE) surfaces were greater than that of the untreated CLPE surface. The PMPC grafting contributed significantly to wear reduction in a hip-joint simulator wear test. Despite high-dose gamma-ray irradiation for cross-linking and further UV irradiation for PMPC grafting, the substrate modified by vitamin E blending maintained high-oxidative stability because vitamin E is an extremely efficient radical scavenger. Furthermore, the mechanical properties of the substrate remained almost unchanged even after PMPC grafting or vitamin E blending, or both PMPC grafting and vitamin E blending. In conclusion, the PMPC-grafted HD-CLPE(VE) provided simultaneously high-wear resistance, oxidative stability, and mechanical properties.

  18. Rapid, facile microwave-assisted synthesis of xanthan gum grafted polyaniline for chemical sensor.

    PubMed

    Pandey, Sadanand; Ramontja, James

    2016-08-01

    Grafting method, through microwave radiation procedure is extremely productive in terms of time consumption, cost effectiveness and environmental friendliness. In this study, conductive and thermally stable composite (mwXG-g-PANi) was synthesized by grafting of aniline (ANi) on to xanthan gum (XG) using catalytic weight of initiator, ammonium peroxydisulfate in the process of microwave irradiation in an aqueous medium. The synthesis of mwXG-g-PANi were confirm by FTIR, XRD, TGA, and SEM. The influence of altering the microwave power, exposure time of microwave, concentration of monomer and the amount of initiator of graft polymerization were studied over the grafting parameters, for example, grafting percentage (%G) and grafting efficiency (%E). The maximum %G and %E achieved was 172 and 74.13 respectively. The outcome demonstrates that the microwave irradiation strategy can increase the reaction rate by 72 times over the conventional method. Electrical conductivity of XG and mwXG-g-PANi composite film was performed. The fabricated grafted sample film were then examined for the chemical sensor. The mwXG-g-PANi, effectively integrated and handled, are NH3 sensitive and exhibit a rapid sensing in presence of NH3 vapor. Chemiresistive NH3 sensors with superior room temperature sensing performance were produced with sensor response of 905 at 1ppb and 90% recovery within few second.

  19. Radiation-grafted, chemically modified membranes part I - Synthesis of a selective aluminum material

    NASA Astrophysics Data System (ADS)

    Bazante-Yamaguishi, Renata; Moura, Eduardo; Manzoli, José E.; Geraldo, Aurea B. C.

    2014-01-01

    Polymeric membranes were styrene grafted by irradiation methods and the obtained material was chemically modified to become aluminum selective. For this purpose, polymeric substrates of PVC (polyvinyl chloride) and PP (polypropylene) were styrene grafted mutually by gamma and electron beam irradiation. The modification process includes three basic reaction paths: Friedel-Crafts acylation, 2-methylanisole coupling and a final oxidation to achieve aluminum selectivity. Although this specific chemical modification in derivatives of polystyrene is not new, the new challenge is to obtain a selective material where original membrane characteristics (physical shape and mechanical resistance) are minimally conserved after such an aggressive treatment.

  20. Practical dosimetric aspects of blood and blood product irradiation

    SciTech Connect

    Fearon, T.C.; Luban, N.L.

    1986-09-01

    The method of choice to reduce susceptibility to transfusion-transmitted graft-versus-host disease is irradiation of allogenic blood and blood products for transfusion to immunosuppressed recipients. Optimal irradiation requires delivery of a known and homogeneous absorbed dose. The use of absorbed dose in air measured at the center of the irradiation volume without proper compensation for sample absorption can lead to approximately 20 percent underexposure. A lucite cylinder was used to provide the delivery of a homogeneous irradiation dose to blood products of different volumes by allowing rotation of the product.

  1. Pretransfusion blood irradiation: Clinical rationale and dosimetric considerations

    SciTech Connect

    Masterson, M.E.; Febo, R. )

    1992-05-01

    The irradiation of blood before transfusion into immunosuppressed patients is an increasingly common technique used to prevent graft-versus-host disease. A technical procedure is described for the calibration of blood irradiators, including the determination of absolute dose rate and relative dose distribution over the blood volume. Results of dose rate measurements on commercially available irradiators indicate differences of +5% to {minus}13% with manufacturer-supplied calibrations and variations in the relative dose rate over the irradiation volume from 70% to 180%. The clinical implications of these findings and the need for accurate dosimetry are discussed.

  2. Liver steatosis in pre-transplant liver biopsies can be quantified rapidly and accurately by nuclear magnetic resonance analysis.

    PubMed

    Bertram, Stefanie; Myland, Cathrin; Swoboda, Sandra; Gallinat, Anja; Minor, Thomas; Lehmann, Nils; Thie, Michael; Kälsch, Julia; Pott, Leona; Canbay, Ali; Bajanowski, Thomas; Reis, Henning; Paul, Andreas; Baba, Hideo A

    2017-02-01

    Donor livers marginally acceptable or acceptable according to extended criteria are more frequently transplanted due to the growing discrepancy between demand and availability of donor organs. One type of marginally acceptable graft is a steatotic donor liver, because it is more sensitive to ischemia-reperfusion injury. Thus, quantitative assessment of steatosis is crucial prior to liver transplantation. Extent of steatosis of 49 pre-reperfusion liver biopsies from patients who received orthotopic liver transplantation was assessed by three techniques: semi-quantitative histological evaluation, computerized histomorphometry, and NMR-based estimation of fat content. The findings were correlated to clinical data and to histological examination of corresponding post-reperfusion biopsies for quantification of ischemia-reperfusion injury. We found that values obtained through all three assessment methods were positively correlated. None of the values obtained by the three applied methods correlated with clinical outcome or extent of ischemia-reperfusion injury. Quantitative evaluation of steatosis by NMR yields results comparable to histological and morphometrical assessment. This technique is rapid (<5 min), accurately quantifies fat in donor livers, and provides results that can be used when evaluation by a pathologist is not available.

  3. Femoral impaction grafting

    PubMed Central

    Scanelli, John A; Brown, Thomas E

    2013-01-01

    Femoral impaction grafting is a reconstruction option applicable to both simple and complex femoral component revisions. It is one of the preferred techniques for reconstructing large femoral defects when the isthmus is non-supportive. The available level of evidence is primarily derived from case series, which shows a mean survivorship of 90.5%, with revision or re-operation as the end-point, with an average follow-up of 11 years. The rate of femoral fracture requiring re-operation or revision of the component varies between several large case series, ranging from 2.5% to 9%, with an average of 5.4%. PMID:23362469

  4. Irradiation subassembly

    DOEpatents

    Seim, O.S.; Filewicz, E.C.; Hutter, E.

    1973-10-23

    An irradiation subassembly for use in a nuclear reactor is described which includes a bundle of slender elongated irradiation -capsules or fuel elements enclosed by a coolant tube and having yieldable retaining liner between the irradiation capsules and the coolant tube. For a hexagonal bundle surrounded by a hexagonal tube the yieldable retaining liner may consist either of six segments corresponding to the six sides of the tube or three angular segments each corresponding in two adjacent sides of the tube. The sides of adjacent segments abut and are so cut that metal-tometal contact is retained when the volume enclosed by the retaining liner is varied and Springs are provided for urging the segments toward the center of the tube to hold the capsules in a closely packed configuration. (Official Gazette)

  5. Spasm in Arterial Grafts in Coronary Artery Bypass Grafting Surgery.

    PubMed

    He, Guo-Wei; Taggart, David P

    2016-03-01

    Spasm of arterial grafts in coronary artery bypass grafting surgery is still a clinical problem, and refractory spasm can occasionally be lethal. Perioperative spasm in bypass grafts and coronary arteries has been reported in 0.43% of all coronary artery bypass grafting surgery, but this may be an underestimate. Spasm can develop not only in the internal mammary artery but more frequently in the right gastroepiploic and radial artery. The mechanism of spasm can involve many pathways, particularly those involving regulation of the intracellular calcium concentration. Endothelial dysfunction also plays a role in spasm. Depending on the clinical scenario, the possibility of spasm during and after coronary artery bypass grafting should be confirmed by angiography. If present, immediate intraluminal injection of vasodilators is often effective, although other procedures such as an intraaortic balloon pump or extracorporeal membrane oxygenation may also become necessary to salvage the patient. Prevention of spasm involves many considerations, and the principles are discussed in this review article.

  6. The efficacy of the use of IR laser phototherapy (LPT) on bone defect grafted with biphasic ceramic on rats with iron deficiency anemia: Raman spectroscopy analysis.

    PubMed

    Rosa, Cristiane Becher; de Castro, Isabele Cardoso Vieira; Júnior, João Alves Reis; Aragão, Juliana Silveira; Barbosa, Artur Felipe Santos; Silveira, Landulfo; Pinheiro, Antonio L B

    2014-05-01

    The aim of this study was to evaluate bone repair in anemic and non-anemic rats submitted or not to laser phototherapy and hydroxyapatite graft. Animals were divided in eight groups of five animals: Clot; Laser; Graft; Graft + Laser; iron deficiency anemia (IDA) + Clot; IDA + Laser; IDA + graft; IDA + graft + Laser. When appropriate irradiation with infrared laser was done during 15 days at a 48-h interval. Animals were killed at day 30; samples were analyzed by Raman spectroscopy. Three shifts were studied and statistically analyzed: ~960, ~1,070, and ~1,454 cm(-1). Graft + laser showed highest ~960 peak was statistically different from all other healthy groups. No statistical difference was found between Clot and IDA + Clot in any shift. The IDA + Graft and IDA + Graft + Laser groups had low mean peak values for shifts ~960, ~1,070, and ~1,454 cm(-1). The results in this study indicate that using hydroxyapatite (HA) and laser irradiation in healthy subjects is favorable to mineral deposition and bone maturation, this being of importance for some groups at risk, such as astronauts. In iron deficiency anemia cases, the use of graft, associated or not to laser irradiation, resulted in low collagen and low carbonate and phosphate HA.

  7. Long Term Clinical Outcome of Patients with Severe Combined Immunodeficiency who Received Related Donor Bone Marrow Transplants without Pre-transplant Chemotherapy or Post-transplant GVHD Prophylaxis

    PubMed Central

    Railey, Mary Dell; Lokhnygina, Yuliya; Buckley, Rebecca H.

    2009-01-01

    Objective To determine long term health benefits of non-ablative bone marrow transplantation for severe combined immunodeficiency (SCID), we investigated our cohort of 161 related donor bone marrow transplanted SCID patients. Only 16 (10%) had HLA-identical donors. Study design All 124 survivors were sent questionnaires about their current clinical statuses. Details from clinic visits were also compiled. One hundred eleven patients (90%) were reached. We compared outcomes of patients transplanted before and after 3.5 months of life and by molecular defect. Results The overall survival rate is 77%, but the rate for the 48 infants transplanted in the first 3.5 months of life is 94%, compared with 70% for the 113 transplanted after 3.5 months (p=0.002). Twenty-eight (76%) of the 37 deceased patients died from viral infections present at diagnosis. One or more clinical problems were reported to have been present in the past two years in 71 (64%) of the survivors, although 95 (86%) are considered healthy by their families. Conclusions Most patients with SCID transplanted with related donor marrow without pre-transplant chemotherapy have done well long-term, but those transplanted at <3.5 months of age had a superior survival rate, a lower rate of clinical problems, less need for booster transplants and better nutritional status. PMID:19818451

  8. Asymptomatic inferior vena cava abnormalities in three children with end-stage renal disease: risk factors and screening guidelines for pretransplant diagnosis.

    PubMed

    Thomas, S E; Hickman, R O; Tapper, D; Shaw, D W; Fouser, L S; McDonald, R A

    2000-02-01

    We report two children with end-stage renal disease (ESRD) found to have inferior vena cava (IVC) thrombosis at the time of renal transplantation. The children suffered from renal diseases that included congenital hepatic fibrosis and portal hypertension as part of their pathophysiology. Neither child had evidence of hypercoaguability or clinical symptoms of IVC thrombosis. Prior to transplantation, the renal replacement therapy consisted primarily of peritoneal dialysis. During their hospital courses, these children had central venous catheters placed for temporary hemodialysis, episodes of peritonitis and numerous abdominal surgeries. The medical literature to date has not identified a link between IVC thrombosis and portal hypertension, nor has an association between the patients' primary renal disease and IVC thrombosis been found. We also report the finding of asymptomatic IVC narrowing in a third patient with obstructive uropathy, colonic dysmotility and numerous abdominal surgeries. IVC narrowing was diagnosed by CT scan during his pretransplant evaluation. In this paper, we consider similarities between these three patients that may have predisposed each of them to asymptomatic IVC pathology, including large-bore central venous access as young children and/or recurrent scarring abdominal processes. A discussion regarding appropriate screening of the 'high-risk patient' for IVC pathology prior to kidney transplantation and surgical options for children with this rare complication are presented.

  9. Methods of fiber surface grafting for interphase design and tailored composite response

    NASA Astrophysics Data System (ADS)

    Arnold, Jesse Judson

    1997-11-01

    The objective of this research was to develop methods of fiber surface grafting for interphase formation, and to experimentally evaluate and model these interphases in order to further elucidate their role in fiber-reinforced composites. Surface modification by sp{60}Co gamma irradiation was used initially to graft acrylic polymers on the surface of ultra-high modulus (UHMPE) fibers. This technique utilized low dose rates and low total doses, and achieved grafting with retention of the exceptional UHMPE properties. The surface properties of the fibers were evaluated using fourier transform infra-red spectroscopy (FTIR), electron spectroscopy for chemical analysis (ESCA), and mechanical tests and dynamic mechanical spectrometry (DMS) of discontinuous fiber composites. Depending on the glass transition temperature, Tg, and chemical structure of the graft, the fiber/matrix adhesion and the interfacial failure mechanism was tailored to provide either enhanced reinforcement or toughening. Using a three-phase block model, the DMS characteristics of the composites were modeled and the reinforcement efficiencies extrapolated as a function of surface treatment. The model successfully predicts the tan delta response of the composite and the appearance of additional loss dispersions associated with the interphase. However, the interactions between the high-energy gamma radiation and the fiber and grafts yield interphases that are difficult to characterize and control. The hydroperoxidation grafting method was subsequently developed, which permitted the grafting of tethered, linear chains by a free radical-type polymerization. Poly(styrene-stat-acrylonitrile) was grafted initially, in which the nitrogen in acrylonitrile was used as a marker to verify grafting and to estimate the grafting efficiency by ESCA analysis. Tapping modesp{TM} atomic force microscopy (TMAFM) images of the grafted fibers revealed a nodular surface topography with dimensions that were correlated to the

  10. Polyether/Polyester Graft Copolymers

    NASA Technical Reports Server (NTRS)

    Bell, Vernon L., Jr.; Wakelyn, N.; Stoakley, D. M.; Proctor, K. M.

    1986-01-01

    Higher solvent resistance achieved along with lower melting temperature. New technique provides method of preparing copolymers with polypivalolactone segments grafted onto poly (2,6-dimethyl-phenylene oxide) backbone. Process makes strong materials with improved solvent resistance and crystalline, thermally-reversible crosslinks. Resulting graft copolymers easier to fabricate into useful articles, including thin films, sheets, fibers, foams, laminates, and moldings.

  11. Graft selection in cerebral revascularization.

    PubMed

    Baaj, Ali A; Agazzi, Siviero; van Loveren, Harry

    2009-05-01

    Cerebral revascularization constitutes an important treatment modality in the management of complex aneurysms, carotid occlusion, tumor, and moyamoya disease. Graft selection is a critical step in the planning of revascularization surgery, and depends on an understanding of graft and regional hemodynamics, accessibility, and patency rates. The goal of this review is to highlight some of these properties.

  12. Grafting effects on vegetable quality

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Vegetable grafting began in the 1920s to control soil-borne disease. It is now a common practice in Asia, parts of Europe, and the Middle East. In Japan and Korea most of the cucurbits and tomatoes (Lycopersicon esculentum Mill.) grown are grafted. This practice is rare in the U.S. and there have...

  13. Continuous ACL graft, results

    PubMed Central

    Díaz, Jorge Luis; Vega, Marcelo; Matesevach, Ivan

    2017-01-01

    Objectives: describe our technique using hamstring graft that respects the proximal continuity of Semitendinosus and uses the superior biological potential of the distal periosteum., preserving and stressing the ST reinforce the retropulsión and dynamic control of external rotation of the knee. Here the technique, results, difficulties and foundations. Methods: The sample of this research was composed of 229 cases operated between 01/03/97 and 01/03/13 in Arthroscopy Private Center., 166 male and 63 female, the postop follow-up was 86 months. Evaluated with IKDC, Lysholm, Hamstring EMG. Comparative histology study in rabbits. Results: IKDC and Lysholm score showed 93% of very good results. Conclusion: Dynamic ACL reconstruction achieves a static-dynamic stabilization of the knee. Grafts have a plus in their biological potential (proximal continuity - osteo-periosteal insertion of the tendons in the femoral tunnel). The hamstring maintains its functionality (EMG). 93% satisfactory results (IKDC, Lysholm). It is a valid surgical option in ACL injuries.

  14. Predictive model for delayed graft function based on easily available pre-renal transplant variables.

    PubMed

    Zaza, Gianluigi; Ferraro, Pietro Manuel; Tessari, Gianpaolo; Sandrini, Silvio; Scolari, Maria Piera; Capelli, Irene; Minetti, Enrico; Gesualdo, Loreto; Girolomoni, Giampiero; Gambaro, Giovanni; Lupo, Antonio; Boschiero, Luigino

    2015-03-01

    Identification of pre-transplant factors influencing delayed graft function (DGF) could have an important clinical impact. This could allow clinicians to early identify dialyzed chronic kidney disease (CKD) patients eligible for special transplant programs, preventive therapeutic strategies and specific post-transplant immunosuppressive treatments. To achieve these objectives, we retrospectively analyzed main demographic and clinical features, follow-up events and outcomes registered in a large dedicated dataset including 2,755 patients compiled collaboratively by four Italian renal/transplant units. The years of transplant ranged from 1984 to 2012. Statistical analysis clearly demonstrated that some recipients' characteristics at the time of transplantation (age and body weight) and dialysis-related variables (modality and duration) were significantly associated with DGF development (p ≤ 0.001). The area under the receiver-operating characteristic (ROC) curve of the final model based on the four identified variables predicting DGF was 0.63 (95 % CI 0.61, 0.65). Additionally, deciles of the score were significantly associated with the incidence of DGF (p value for trend <0.001). Therefore, in conclusion, in our study we identified a pre-operative predictive model for DGF, based on inexpensive and easily available variables, potentially useful in routine clinical practice in most of the Italian and European dialysis units.

  15. [Stent Grafting for Aortic Dissection].

    PubMed

    Uchida, Naomichi

    2016-07-01

    The purpose of stent graft for aortic dissection is to terminate antegrade blood flow into the false lumen through primary entry. Early intervention for primary entry makes excellent aortic remodeling and emergent stent grafting for complicated acute type B aortic dissection is supported as a class I. On the other hand stent grafting for chronic aortic dissection is controversial. Early stent grafting is considered with in 6 months after on-set if the diameter of the descending aorta is more than 40 mm. Additional interventions for residual false lumen on the downstream aorta are still required. Stent graft for re-entry, candy-plug technique, and double stenting, other effective re-interventions were reported. Best treatment on the basis of each anatomical and physical characteristics should be selected in each institution. Frozen elephant trunk is alternative procedure for aortic dissection without the need to take account of proximal anatomical limitation and effective for acute type A aortic dissection.

  16. Irradiated foods

    MedlinePlus

    ... it reduces the risk of food poisoning . Food irradiation is used in many countries. It was first approved in the U.S. to prevent sprouts on white potatoes, and to control insects on wheat and in certain spices and seasonings.

  17. Graft polymerization of acrylic acid and methacrylic acid onto poly(vinylidene fluoride) powder in presence of metallic salt and sulfuric acid

    NASA Astrophysics Data System (ADS)

    Deng, Bo; Yu, Yang; Zhang, Bowu; Yang, Xuanxuan; Li, Linfan; Yu, Ming; Li, Jingye

    2011-02-01

    Poly(vinylidene fluoride) (PVDF) powder was grafted with acrylic acid (AAc) or methacrylic acid (MAA) by the pre-irradiation induced graft polymerization technique. The presence of graft chains was proven by FT-IR spectroscopy. The degree of grafting (DG) was calculated by the acid-base back titration method. The synergistic effect of acid and Mohr's salt on the grafting kinetics was examined. The results indicated that adding sulfuric acid and Mohr's salt simultaneously in AAc or MAA solutions led to a strong enhancement in the degree of grafting. The grafted PVDF powder was cast into microfiltration (MF) membranes using the phase inversion method and some properties of the obtained MF membranes were characterized.

  18. Study and Optimization on graft polymerization under normal pressure and air atmospheric conditions, and its application to metal adsorbent

    NASA Astrophysics Data System (ADS)

    Ueki, Yuji; Chandra Dafader, Nirmal; Hoshina, Hiroyuki; Seko, Noriaki; Tamada, Masao

    2012-07-01

    Radiation-induced graft polymerization of glycidyl methacrylate (GMA) onto non-woven polyethylene (NWPE) fabric was achieved under normal pressure and air atmospheric conditions, without using unique apparatus such as glass ampoules or vacuum lines. To attain graft polymerization under normal pressure and air atmospheric conditions, the effects of the pre-irradiation dose, pre-irradiation atmosphere, pre-irradiation temperature, de-aeration of GMA-emulsion, grafting atmosphere in a reactor, and dissolved oxygen (DO) concentration in GMA-emulsion on the degree of grafting (Dg) were investigated in detail. It was found that the DO concentration had the strongest influence, the pre-irradiation dose, de-aeration of emulsion and grafting atmosphere had a relatively strong impact, and the pre-irradiation atmosphere and pre-irradiation temperature had the least effect on Dg. The optimum DO concentration before grafting was 2.0 mg/L or less. When a polyethylene bottle was used as a reactor instead of a glass ampoule, graft polymerization under normal pressure and air atmospheric conditions could be achieved under the following conditions; the pre-irradiation dose was more than 50 kGy, the volume ratio of GMA-emulsion to air was 50:1 or less, and the DO concentration in GMA-emulsion during grafting was below 2.0 mg/L. Under these grafting conditions, Dg was controlled within a range of up to 362%. The prepared GMA-grafted NWPE (GMA-g-NWPE) fabric was modified with a phosphoric acid to obtain an adsorbent for heavy metal ions. In the column-mode adsorption tests of Pb(II), the adsorption performance of the produced phosphorylated GMA-g-NWPE fabric (fibrous metal adsorbent) was not essentially dependent on the flow rate of the feed. The breakthrough points of 200, 500, and 1000 h-1 in space velocity were 483, 477 and 462 bed volumes, and the breakthrough capacities of the three flow rates were 1.16, 1.15 and 1.16 mmol-Pb(II)/g-adsorbent.

  19. Syntheses of amine-type adsorbents with emulsion graft polymerization of glycidyl methacrylate

    NASA Astrophysics Data System (ADS)

    Seko, N.; Bang, L. T.; Tamada, M.

    2007-12-01

    Glycidyl methacrylate (GMA) which was precursor monomer for the synthesis of metal ion adsorbent was emulsified by surfactant of Tween 20 (Tw-20). The emulsion of 5% GMA in the water was stable for 48 h at Tw-20 concentration of 0.5%. Graft polymerization of GMA on polyethylene fiber was carried out in the emulsion state at various pre-irradiation doses. Degree of grafting (Dg) reached 103%, 301% and 348% for 1 h grafting at 40 °C with pre-irradiation of 10, 30 and 40 kGy, respectively. But the Dg was depressed when the pre-irradiation dose was over 50 kGy since cross-linking occurred simultaneously in the trunk polymer. Dg decreased with increment of Tw-20 concentration in emulsion of 5% GMA at pre-irradiation of 40 kGy. The three kinds of amine-type adsorbents were synthesized by reacting diethylenetriamine (DETA), triethylenetetramine (TETA) and ethylenediamine (EDA) with GMA-grafted polyethylene fiber. The synthesized EDA-type adsorbent had the highest selectivity against U ion and the distribution coefficient was 2.0 × 10 6.

  20. Engineered Water Highways in Fuel Cells: Radiation Grafting of Gas Diffusion Layers.

    PubMed

    Forner-Cuenca, Antoni; Biesdorf, Johannes; Gubler, Lorenz; Kristiansen, Per Magnus; Schmidt, Thomas Justus; Boillat, Pierre

    2015-11-04

    A novel method to produce gas diffusion layers with patterned wettability for fuel cells is presented. The local irradiation and subsequent grafting permits full design flexibility and wettability tuning, while modifying throughout the whole material thickness. These water highways have improved operando performance due to an optimized water management inside the cells.

  1. Surface modification by γ-ray-induced grafting of PDMAEMA/PEGMEMA onto PE films

    NASA Astrophysics Data System (ADS)

    Titaux, G. A.; Contreras-García, A.; Bucio, E.

    2009-07-01

    Radiation grafting of poly[2-(dimethylamino) ethyl methacrylate] (PDMAEMA) and poly(ethylene glycol) methyl ether methacrylate (PEGMEMA) onto polyethylene (PE) films was synthesized using gamma radiation from a 60Co source. PE was modified by the PDMAEMA and PEGMEMA by pre-irradiation and one-step method. Grafting as a function of the pre-irradiation dose between 50 and 200 kGy, dose rate of 9 kGy h -1, and monomer concentration 50% of PDMAEMA/PEGMEMA (1/1) in toluene. The characterization of the graft copolymer obtained was carried out by FTIR-ATR, TGA, and DSC. Stimuli-responsive behavior and critical pH point were studied by swelling in water, pH and thermo-responsive films of PE-g-(DMAEMA/PEGMEMA) presented a lower critical solution temperature (LCST) of 55 °C and critical pH point around 8.5.

  2. Are Aortic Stent Grafts Safe in Pregnancy?

    PubMed Central

    Khandanpour, Nader; Mehta, Tapan A.; Adiseshiah, M.; Meyer, Felicity J.

    2015-01-01

    Aortic stent grafts are increasingly used to treat aortic aneurysms and also other aortic pathologies. The safety of aortic stent grafts in pregnancy has never been studied or reported. We report on two cases of aortic stent grafts in pregnant women and discuss the effect of pregnancy on these aortic stent grafts. PMID:26229702

  3. Radiation-induced graft copolymerization of binary monomer mixture containing acrylonitrile onto polyethylene films

    NASA Astrophysics Data System (ADS)

    Choi, Seong-Ho; Nho, Young Chang

    2000-04-01

    Graft copolymerization of acrylonitrile (AN)/acrylic acid (AA), acrylonitrile (AN)/methacrylic acid (MA), and acrylonitrile (AN)/glycidyl methacrylate (GMA) onto pre-irradiated polyethylene (PE) films were studied. The effect of reaction conditions such as solvents, additives, and monomer composition on the grafting yields was investigated. The extent of grafting was found to increase with increasing sulfuric acid concentration when sulfuric acid as an additive was added to the grafting solution. In AN/AA mixture, the proportion of acrylonitrile in the copolymer increased with an increasing AN component in feed monomers. On the other hand, in AN/MA mixture, acrylonitrile component in copolymer was very slight in spite of the increase AN component in feed monomers. In the AN/GMA mixture, the proportion of acrylonitrile in the copolymer increased with increasing acrylonitrile component in AN/GMA feed monomer.

  4. EPR investigation on radiation-induced graft copolymerization of styrene onto polyethylene: Energy transfer effects

    NASA Astrophysics Data System (ADS)

    Salih, M. A.; Buttafava, A.; Ravasio, U.; Mariani, M.; Faucitano, A.

    2007-08-01

    In this paper, energy transfer phenomena concerning the in-source graft copolymerization of styrene onto LDPE were investigated through the EPR analysis of the radical intermediates. The model solution experiments have shown a substantial deviation of the experimental G (radicals) values with respect to the additivity law, which reflect the negative effect of the styrene monomer concentration on the initiation rate of the graft copolymerization. The EPR measurements performed on polyethylene- co-styrene graft copolymers of various composition following low-temperature vacuum gamma irradiation have confirmed the decrease of the total radical yields with increasing the styrene concentration. The effect was partly attributed to the heterogeneity of the graft copolymer matrix and to the lack of molecular mobility in the solid state at low temperature, which prevents the attainment of the favourable geometrical configurations in intermolecular energy and charge transfer events.

  5. Lysozyme immobilization onto PVC catheters grafted with NVCL and HEMA for reduction of bacterial adhesion

    NASA Astrophysics Data System (ADS)

    Guadarrama-Zempoalteca, Yesica; Díaz-Gómez, Luis; Meléndez-Ortiz, H. Iván; Concheiro, Angel; Alvarez-Lorenzo, Carmen; Bucio, Emilio

    2016-09-01

    The aim of the present work was to functionalize poly(vinyl chloride) (PVC) urinary catheters with grafted copolymers that can improve the biocompatibility and serve as binding points of lysozyme. PVC catheters were modified by grafting a mixture of N-vinylcaprolactam (NVCL) and 2-hydroxyethylmethacrylate (HEMA) applying a gamma-ray pre-irradiation method. The effect of absorbed dose, monomer concentration, temperature, and reaction time on the grafting percentage was evaluated. The grafted catheters were characterized regarding surface composition (FTIR-ATR spectroscopy), thermal properties (DSC and TGA) and swelling in aqueous medium. Lysozyme was directly coupled onto PVC-g-(NVCL/HEMA) previously activated using carbonyldiimidazole. Antimicrobial lytic activity of the modified catheters over time was tested against Micrococcus lysodeikticus. Lysozyme diminished the adhesion of Staphylococcus aureus onto the functionalized catheters, which may be suitable to prevent biofilm formation.

  6. Design and Validation of an Augmented Hematopoietic Cell Transplantation-Comorbidity Index Comprising Pretransplant Ferritin, Albumin, and Platelet Count for Prediction of Outcomes after Allogeneic Transplantation.

    PubMed

    Vaughn, Jennifer E; Storer, Barry E; Armand, Philippe; Raimondi, Roberto; Gibson, Christopher; Rambaldi, Alessandro; Ciceri, Fabio; Oneto, Rosi; Bruno, Benedetto; Martin, Paul J; Sandmaier, Brenda M; Storb, Rainer; Sorror, Mohamed L

    2015-08-01

    Pretransplant values of serum ferritin, albumin, and peripheral blood counts were previously suggested to provide prognostic information about hematopoietic cell transplantation (HCT) outcomes. Whether these "biomarkers" have prognostic value independent of each other and the HCT-comorbidity index (HCT-CI) is unknown. We analyzed data from 3917 allogeneic HCT recipients at multiple sites in the United States and Italy using multivariate models including each biomarker and the HCT-CI. Data from all sites were then randomly divided into a training set (n = 2352) to develop weights for the relevant biomarkers to be added to the HCT-CI scores and a validation set (n = 1407) to validate an augmented HCT-CI compared with the original index. Multivariate analysis with data from one site showed that ferritin, albumin, and platelets-not neutrophils or hemoglobin-were independently associated with increased nonrelapse mortality (NRM) and decreased overall survival. Findings were validated in data from the other sites. Subsequently, in a training set from all sites, ferritin >2500 mg/dL (hazard ratio [HR], 1.69); albumin 3 to 3.5 g/dL (HR, 1.61) and <3.0 g/dL (HR, 2.27); and platelets 50 to <100,000 (HR, 1.28), 20 to <50,000 (HR, 1.29), and <20,000 (HR, 1.55) were statistically significantly associated with NRM. Weights were assigned to these laboratory values following the same equation used to design the original index. In the validation set, the addition of the biomarkers to the original index to develop an augmented HCT-CI resulted in a statistically significant increase in a higher c-statistic estimate for prediction of NRM (P = .0007). Ferritin, albumin, and platelet counts are important prognostic markers that further refine the discriminative power of the HCT-CI for transplant outcomes.

  7. Design and Validation of an Augmented Hematopoietic Cell Transplantation-Comorbidity Index Comprising Pre-transplant Ferritin, Albumin and Platelet Count for Prediction of Outcomes after Allogeneic Transplantation

    PubMed Central

    Vaughn, Jennifer E.; Storer, Barry; Armand, Philippe; Raimondi, Roberto; Gibson, Christopher; Rambaldi, Alessandro; Ciceri, Fabio; Oneto, Rosi; Bruno, Benedetto; Martin, Paul J.; Sandmaier, Brenda M.; Storb, Rainer; Sorror, Mohamed L.

    2015-01-01

    Purpose Pre-transplant values of serum ferritin, albumin and peripheral blood counts were previously suggested to provide prognostic information about hematopoietic cell transplantation (HCT) outcomes. Whether these “biomarkers” have prognostic value independent of each other and the HCT-comorbidity index (HCT-CI) is unknown. Patients and Methods We analyzed data from 3917 allogeneic HCT recipients at multiple sites in the US and Italy using multivariate models including each biomarker and the HCT-CI. Data from all sites were then randomly divided into a training set (n=2352) to develop weights for the relevant biomarkers to be added to the HCT-CI scores and a validation set (n=1407) to validate an augmented HCT-CI compared to the original index. Results Multivariate analysis with data from one site showed that ferritin, albumin and platelets-- not neutrophils or hemoglobin--were independently associated with increased non-relapse mortality (NRM) and decreased overall survival. Findings were validated in data from the other sites. Subsequently, in a training set from all sites, ferritin >2500 mg/dL (HR:1.69); albumin 3–3.5 g/dL (HR:1.61) and <3.0 g/dL (HR:2.27); and platelets 50–<100,000 (HR:1.28), 20–<50,000 (HR:1.29) and <20,000 (HR:1.55) were statistically significantly associated with NRM. Weights were assigned to these laboratory values following the same equation used to design the original index. In the validation set, The addition of the biomarkers to the original index to develop an augmented HCT-CI resulted in a statistically significant increase in higher c-statistic estimate for prediction of NRM. (p=0.0007). Conclusion Ferritin, albumin, and platelet counts are important prognostic markers that further refine the discriminative power of the HCT-CI for transplant outcomes. PMID:25862589

  8. Polyethylene terephthalate membrane grafted with peptidomimetics: endothelial cell compatibility and retention under shear stress.

    PubMed

    Rémy, Murielle; Bareille, Reine; Rerat, Vincent; Bourget, Chantal; Marchand-Brynaert, Jacqueline; Bordenave, Laurence

    2013-01-01

    The present work aimed to treat a polyethylene terephthalate (PET) surface to make the biomaterial more 'attractive' in terms of attachment and shear stress response to endothelial cells with a view to possible applications in vascular grafting. A surface wet-chemistry protocol was applied to graft track-etched PET membranes with RGD peptidomimetics based on the tyrosine template and active at the nano-level vs. isolated human αvβ3 receptor, which was monitored by X-ray photoelectron spectroscopy, contact angle measurement and atomic force microscopy for characterization. A primary culture of human saphenous vein endothelial cells was used before and after sterilization of the membranes (heat treatment or γ-ray irradiation) to test the benefit of grafting. The optimal surface concentrations of grafted molecules were around 50 pmol/cm². Compared to GRGDS, the peptidomimetics promoted cell attachment with similar or slightly better performances. Endothelialized grafted supports were further exposed to 2 h of shear stress mimicking arterial conditions. Cells were lost on non-grafted PET whereas cells on grafted polymers sterilized by γ-ray irradiation withstood forces with no significant difference in focal contacts. At the mRNA level, cells on functionalized PET were able to respond to shear stress with NFkB upregulation. Thus, grafting of peptidomimetics as ligands of the αvβ3 integrin could be a relevant strategy to improve the adhesion of human endothelial cells and to obtain an efficient endothelialized PET for the surgery of small-diameter vascular prostheses.

  9. Radiation-grafting of vinyl monomers separately onto polypropylene monofilament sutures

    NASA Astrophysics Data System (ADS)

    López-Saucedo, Felipe; Alvarez-Lorenzo, Carmen; Concheiro, Angel; Bucio, Emilio

    2017-03-01

    N-isopropylacrylamide (NIPAAm), 2-hydroxyethylmethacrylate (HEMA) and N-vinylimidazole (NVIm) were grafted separately onto polypropylene (PP) monofilament sutures. These grafted copolymers have properties with potential application in the synthesis of new medical devices. Co-60 gamma radiation was employed with dose rate of 9.2 kGyh-1 in synthesis of copolymers with different grafting percentages: PP-g-PNIPAAm from 11% to 175%, PP-g-PHEMA from 6% to 130%, and PP-g-PNVIm from 10% to 17%. Both NIPAAm and HEMA were grafted applying the pre-irradiation method under different reaction conditions: dose, temperature, monomer concentration and reaction time; NVIm was grafted by simultaneous method with doses from 20 up to 60 kGy. Grafted polymers were characterized by FTIR-ATR, TGA and DSC; and their swelling in water was recorded. Modified suture PP-g-PNIPAAm had thermo-responsive properties while PP-g-PNVIm exhibited pH-sensitive swelling. Overall, the implemented grafting strategies provided a hydrophilic surface layer that did not cause detrimental effects on mechanical properties and cytocompatibility of the sutures.

  10. Mechanical properties of radiation-sterilised human Bone-Tendon-Bone grafts preserved by different methods.

    PubMed

    Kamiński, A; Gut, G; Marowska, J; Lada-Kozłowska, M; Biwejnis, W; Zasacka, M

    2009-08-01

    Patellar tendon auto- and allo-grafts are commonly used in orthopedic surgery for reconstruction of the anterior cruciate ligaments (ACL). Autografts are mainly used for primary reconstruction, while allografts are useful for revision surgery. To avoid the risk of infectious disease transmission allografts should be radiation-sterilised. As radiation-sterilisation supposedly decreases the mechanical strength of tendon it is important to establish methods of allograft preservation and sterilisation assuring the best quality of grafts and their safety at the same time. Therefore, the purpose of this study was to compare the tensile strength of human patellar tendon (cut out as for ACL reconstruction), preserved by various methods (deep fresh freezing, glycerolisation, lyophilisation) and subsequently radiation-sterilised with doses of 0, 25, 50 or 100 kGy. Bone-Tendon-Bone grafts (BTB) were prepared from cadaveric human patella tendons with both patellar and tibial attachments. BTB grafts were preserved by deep freezing, glycerolisation or lyophilisation and were subsequently radiation-sterilised with doses of 0 (control), 25, 50 or 100 kGy. All samples were subjected to mechanical failure tensile tests with the use of Instron system in order to estimate their mechanical properties. All lyophilised grafts were rehydrated before performing of those tests. Obtained mechanical tests results of examined grafts suggest that deep-frozen irradiated grafts retain their initial mechanical properties to an extent which does not exclude their clinical application.

  11. Gamma radiation-induced grafting of glycidyl methacrylate (GMA) onto water hyacinth fibers

    NASA Astrophysics Data System (ADS)

    Madrid, Jordan F.; Nuesca, Guillermo M.; Abad, Lucille V.

    2013-04-01

    Water hyacinth fibers (Eichhornia crassipes) were functionalized using radiation-induced graft polymerization of glycidyl methacrylate by γ-rays from 60Co source. The simultaneous grafting technique was employed wherein the water hyacinth fibers were irradiated in nitrogen atmosphere in the presence of glycidyl methacrylate dissolved in water/methanol solvent. The effects of different grafting parameters to the grafting yield were evaluated. The optimal values of solvent, absorbed dose, dose rate, and concentration of monomer were found to be 1:3 (volume/volume) water-methanol solvent, 10 kGy, 8 kGy h-1 dose rate and 5% volume/volume glycidyl methacrylate, respectively. Using the optimum conditions, degree of grafting of approximately 58% was achieved. The grafted water hyacinth fibers were characterized using Attenuated Total Reflectance-Fourier Transformed Infrared Spectroscopy (ATR-FTIR), Thermogravimetric Analysis (TGA), Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDX). The results of these tests confirmed the successful grafting of glycidyl methacrylate onto water hyacinth fibers.

  12. Histoplasma infection of aortofemoral bypass graft.

    PubMed

    Patel, Nishit; Bronze, Michael S

    2014-05-01

    Histoplasma infection of vascular grafts is extremely rare. To our knowledge, there are only 4 cases reported with Histoplasma capsulatum infection of the aortic graft. All had previous disseminated histoplasmosis and atherosclerotic peripheral vascular disease. They were treated surgically with explantation of the infected graft and reimplantation of new graft in extra-anatomic uninfected site. The authors present a new case of H capsulatum infection of aortofemoral bypass graft, but unlike the other cases, this case was managed without surgical intervention.

  13. Dynamics of anti-human leukocyte antigen antibodies after renal transplantation and their impact on graft outcome.

    PubMed

    de Souza, Patrícia Soares; David-Neto, Elias; Panajotopolous, Nicolas; Agena, Fabiana; Rodrigues, Hélcio; Ronda, Carla; David, Daísa Ribeiro; Kalil, Jorge; Nahas, Wiliam Carlos; de Castro, Maria Cristina Ribeiro

    2014-11-01

    The purpose of this study was to sequentially monitor anti-HLA antibodies and correlate the results with antibody-mediated rejection (AMR), graft survival (GS), and graft function (GF). We collected sera from 111 kidney transplant recipients on transplant days 0, 7, 14, 30, 60, 90, 180, and 360 and analyzed PRA levels by ELISA. DSAs were analyzed by single-antigen beads in rejecting kidneys. At pre-transplant, 79.3% of the patients were non-sensitized (PRA = 0%) and 20.7% were sensitized (PRA > 1%). After transplant, patients were grouped by PRA profile: no anti-HLA antibodies pre- or post-transplant (group HLApre-/post-; n = 80); de novo anti-HLA antibodies post-transplant (group HLApre-/post+; n = 8); sensitized pre-transplant/increased PRA post-transplant (group HLApre+/post↑; n = 9); and sensitized pre-transplant/decreased PRA post-transplant (group HLApre+/post↓; n = 14). De novo anti-HLA antibodies were detected at 7-180 d. In sensitized patients, PRA levels changed within the first 30 d post-transplant. Incidence of AMR was higher in HLApre-/post+ and HLApre+/post↑ than in HLApre-/post-, and HLApre+/post↓ (p < 0.001) groups. One-yr death-censored GS was 36% in group HLApre+/post↑, compared with 98%, 88% and 100% in groups HLApre-/post-, HLApre-/post+, and HLApre+/post↓, respectively (p < 0.001). Excluding first-year graft losses, GF and GS were similar among the groups. In conclusion, post-transplant antibody monitoring can identify recipients at higher risk of AMR.

  14. Abaca/polyester nonwoven fabric functionalization for metal ion adsorbent synthesis via electron beam-induced emulsion grafting

    NASA Astrophysics Data System (ADS)

    Madrid, Jordan F.; Ueki, Yuji; Seko, Noriaki

    2013-09-01

    A metal ion adsorbent was developed from a nonwoven fabric trunk material composed of both natural and synthetic polymers. A pre-irradiation technique was used for emulsion grafting of glycidyl methacrylate (GMA) onto an electron beam irradiated abaca/polyester nonwoven fabric (APNWF). The dependence of degree of grafting (Dg), calculated from the weight of APNWF before and after grafting, on absorbed dose, reaction time and monomer concentration were evaluated. After 50 kGy irradiation with 2 MeV electron beam and subsequent 3 h reaction with an emulsion consisting of 5% GMA and 0.5% polyoxyethylene sorbitan monolaurate (Tween 20) surfactant in deionized water at 40 °C, a grafted APNWF with a Dg greater than 150% was obtained. The GMA-grafted APNWF was further modified by reaction with ethylenediamine (EDA) in isopropyl alcohol at 60 °C to introduce amine functional groups. After a 3 h reaction with 50% EDA, an amine group density of 2.7 mmole/gram adsorbent was achieved based from elemental analysis. Batch adsorption experiments were performed using Cu2+ and Ni2+ ions in aqueous solutions with initial pH of 5 at 30 °C. Results show that the adsorption capacity of the grafted adsorbent for Cu2+ is four times higher than Ni2+ ions.

  15. [Kidney grafts from elderly donors].

    PubMed

    Hiesse, Christian; Pessione, Fabienne; Cohen, Sophie

    2003-06-07

    FROM AN EPIDEMIOLOGICAL POINT OF VIEW: The epidemiology of renal transplantation had greatly changed over the past 10 years. The increasing number of patients with renal failure and candidates for transplantation increases the demand for grafts, whereas the sampling rate of organs remains stable. The mean age of the donors is rising, hence underlining the question of the use of organs of so-called "borderline" quality. THE WEAK POINTS OF ELDERLY GRAFTS: Aging of the kidneys affects the structure of the parenchyma and renal function, which decreases, notably in hypertensive persons. The elderly graft exhibits a critical mass of nephrons that is insufficient to fulfil the functional requirements of a poorly equipped recipient. The recipient is more sensitive to the added agressions: prolonged ischemia and immunological and medicinal agressions. THE RESULTS OF RENAL GRAFT FROM ELDERLY DONORS: They are quantitatively and qualitatively inferior to those of renal transplants from "ideal" donors. The donor's age is a significant factor influencing negatively influences the survival of the transplanted kidney, but dependent on past vascular history. Good results regarding the maintenance of dialysis are obtained by selecting the donors and by avoiding added risk factors. THE ASSESSMENT OF A GRAFT FROM AN ELDERLY DONOR: This, basically, relies on clinical criteria: donor's history, cause of death and accurate measurement of the renal function. A biopsy of the graft, at the time of sampling, provides useful information. TRANSPLANTATION STRATEGY OF A GRAFT FROM AN ELDERLY DONOR: Donor-recipient matching by age is a common approach. Grafting of both kidneys in the same recipient is a method presently under assessment. The episode of ischemia must be reduced and the immunosuppressive therapy adapted.

  16. Bone Grafting: Sourcing, Timing, Strategies, and Alternatives.

    PubMed

    Egol, Kenneth A; Nauth, Aaron; Lee, Mark; Pape, Hans-Christoph; Watson, J Tracy; Borrelli, Joseph

    2015-12-01

    Acute fractures, nonunions, and nonunions with bone defects or osteomyelitis often need bone graft to facilitate union. There are several factors to consider when it is determined that a bone graft is needed. These factors include the source of the bone graft (autograft vs. allograft), proper timing for placement of the bone graft, strategies to avoid further complications (particularly in the setting of osteomyelitis), and with the development of a variety of bone graft substitutes, whether alternatives to autograft are available and appropriate for the task at hand. Autograft bone has commonly been referred to as the "gold standard" of bone grafts, against which the efficacy of other grafts has been measured. The best timing for when to place a bone graft or substitute is also somewhat controversial, particularly after an open fracture or a potentially contaminated bed. The treatment of infected nonunions, particularly those that require a graft to facilitate healing, can be quite challenging. Typically, the infection is completely eradicated before placement of a bone graft, but achieving a sterile bed and the timing of a bone graft require strategic thinking and planning. This review outlines the benefits of autografts, the most suitable sites for harvesting bone grafts, the timing of bone graft procedures, the potential risks and benefits of grafting in the face of infection, and the currently available bone graft extenders.

  17. Costal Grafting in Mandibular Reconstruction

    PubMed Central

    Bourlet, Jerôme; Château, Joseph; Jacquemart, Mathieu; Dufour, Clémence; Mojallal, Ali; Gleizal, Arnaud

    2015-01-01

    Background: Reconstruction of mandibular bone defect is a common indication in craniomaxillofacial surgery, and free fibular flap is the gold standard for this indication. However, there are alternatives; nonvascular bone grafting is one of them, and we present the costal grafting for mandibular reconstruction, a classic technique that is reliable, efficient, and produced less morbidity than the technique of using composite free flaps. Method: A 9-year retrospective review of 54 patients treated surgically for mandibular reconstruction was performed. The criterion mainly analyzed was graft survival. The surgical technique was described in detail. Results: A total of 54 patients with mandibular bone defect were identified. Five symphysis, 46 corpus, and 20 ramus defects were considered. These patients underwent reconstruction by costal grafting, and the engrafting was successful in 92.6% of cases. Dental rehabilitation with dental implants was realized in 70% of cases. Conclusions: The approach described in this article allowed the authors to obtain good results with costal grafting for mandibular reconstruction and dental rehabilitation. Costal grafting is a good alternative for fibula free flap in specific indications. Reconstruction of mandibular bone defect is a common indication in craniomaxillofacial surgery. Since the 1980s, the gold standard for these defects is the use of free fibular flap.1 In some cases, this technique is contradicted; the surgeon then has several possibilities for the use of free osteomyocutaneous flaps (iliac crest, scapula, and serrato-costal flaps).2–8 PMID:26893990

  18. Interventions in Infrainguinal Bypass Grafts

    SciTech Connect

    Mueller-Huelsbeck, S. Order, B.-M.; Jahnke, T.

    2006-02-15

    The interventional radiologist plays an important role in the detection and prevention of infrainguinal bypass failure. Early detection and evaluation of flow-limiting lesions effectively preserve graft (venous bypass and polyester or expanded polytetrafluoroethylene bypass) patency by identifying stenoses before occlusion occurs. Delay in treatment of the at-risk graft may result in graft failure and a reduced chance of successful revascularization. For this reason, surveillance protocols form an important part of follow-up after infrainguinal bypass surgery. As well as having an understanding of the application of imaging techniques including ultrasound, MR angiography, CT angiography and digital subtraction angiography, the interventional radiologist should have detailed knowledge of the minimally invasive therapeutic options. Percutaneous transluminal angioplasty (PTA), or alternatively cutting balloon angioplasty, is the interventional treatment of choice in prevention of graft failure and occlusion. Further alternatives include metallic stent placement, fibrinolysis, and mechanical thrombectomy. Primary assisted patency rates following PTA can be up to 65% at 5 years. When the endovascular approach is unsuccessful, these therapeutic options are complemented by surgical procedures including vein patch revision, jump grafting, or placement of a new graft.

  19. Bilateral internal thoracic artery grafting

    PubMed Central

    2013-01-01

    The effectiveness of the left internal mammary artery graft to the anterior descending coronary artery as a surgical strategy has been shown to improve the survival rate and decrease the risk of adverse cardiac events in patients undergoing coronary bypass surgery. These clinical benefits appear to be related to the superior short and long-term patency rates of the internal thoracic artery graft. Although the advantages of using of both internal thoracic arteries (ITA) for bypass grafting have taken longer to prove, recent results from multiple data sets now support these findings. The major advantage of bilateral ITA grafting appears to be improved survival rate, while the disadvantages of complex ITA grafting include the increased complexity of operation, and an increased risk of wound complications. While these short-term disadvantages have been mitigated in contemporary surgical practice, they have not eliminated. Bilateral ITA grafting should be considered the procedure of choice for patients undergoing coronary bypass surgery that have a predicted survival rate of longer than ten years. PMID:23977627

  20. Radicals contributing to preirradiation graft polymerization onto porous polyethylene

    NASA Astrophysics Data System (ADS)

    Uezu, Kazuya; Saito, Kyoichi; Furusaki, Shintaro; Sugo, Takanobu; Ishigaki, Isao

    Porous polyethylene hollow fiber was irradiated by an electron beam at 160 kGy and 8 kGy/min. The concentrations of the radicals such as alkyl, allyl and peroxy were determined by analyzing an integral form of ESR spectra. The comparison of the decay of the radicals with and without contact with air demonstrated that the key radical contributing to the preirradiation graft polymerization is the alkyl radical. The decay of the alkyl radical was simulated by the diffusion-controlled model in the spherical crystallites of polyethylene.

  1. [Graft or CVC? A prosthetic graft is the better choice].

    PubMed

    Cifarelli, M

    2009-01-01

    For more than 30 years, research and industry have attempted to introduce into clinical practice solutions and products that could remedy the impossibility to use native veins. Vascular grafts of various types have been created that would approach the ideal characteristics as closely as possible with low antigenic power, high resistance to infections, low risk of thrombosis, and easy pierceability but high resistance to puncturing. For this purpose various materials, either totally synthetic such as PTFE, biological homologous or heterologous, or biosynthetic with mixed components have been created. In addition, different configurations to improve the hemodynamic outline of synthetic grafts have been studied: grafts of varying caliber, conical or equipped with cuffs, and various systems of wall reinforcement to increase the resistance to punctures. But each of these types favors one aspect over another: biological grafts show better compliance with the native vein but offer less resistance to punctures and ectatic processes; synthetic grafts, instead, tend to be more vulnerable to intimal hyperplasia at the venous anastomosis, which is the Achilles' heel of grafts. In recent years, the use of tunneled central venous catheters (CVCs) has grown exponentially. This has offered a new, important solution to the vascular access problem, but the extensive use of CVCs is not always justified. In comparison with grafts, CVCs have various disadvantages including insertion-related complications, possible malfunctioning, risk of infections and thrombosis, but above all a high risk of steno-occlusion of central veins. Also in this field, research and industry are offering more and more reliable and secure products. More resistant, flexible, tolerable and less thrombogenic materials are being used and various configurations which would offer the best performance with the least insertion-related risks have been introduced: double-lumen CVCs with input and output staggered in oval

  2. Patency of femoropopliteal and femorotibial grafts after outflow revascularization (jump grafts) to bypass distal disease.

    PubMed

    Andros, G; Harris, R W; Dulawa, L B; Oblath, R W; Salles-Cunha, S X

    1984-11-01

    Repair of failing femorodistal bypass grafts with secondary distal "jump" grafts was performed 34 times in 33 patients. Indication for operation was limb salvage for all distal jump grafts and for 85% of the initial femorodistal bypass grafts. Autogenous vein bypass grafts were used in 28 of 33 initial femorodistal grafts (85%) and in 29 of 34 secondary jump grafts (85%). Sixteen of the 33 initial grafts in jeopardy extended to the infrapopliteal level (48%) and 19 of the jump grafts terminated in foot or ankle arteries (56%). The 12 jump grafts performed in the first 2 months of the initial graft were associated with high rates (9%) of graft thrombosis and amputation. Early loss of viability of initial grafts probably resulted from technical and judgment errors or underestimation of distal disease. Progression of distal disease produced late failure after 1 year of implantation of the initial grafts. The 1-year patency rate of the initial femorodistal grafts was 63% but only 32% of these grafted limbs were viable and were not at risk of amputation. Distal jump grafts produced a 49% improvement in limb viability (to an 81% limb salvage rate) and an 11% increase in the initial graft patency rate (to 74%) at 1 year.

  3. Simultaneous radiation induced graft polymerization of N-vinyl-2-pyrrolidone onto polypropylene non-woven fabric for improvement of blood compatibility

    NASA Astrophysics Data System (ADS)

    Li, Rong; Wang, Hengdong; Wang, Wenfeng; Ye, Yin

    2013-07-01

    In this study, N-vinyl-2-pyrrolidone (NVP) was grafted onto polypropylene non-woven fabric (PPNWF) through a simultaneous irradiation induced graft polymerization technique. Effect of the parameters of graft polymerization, i.e., monomer concentration, absorbed dose and dose rate, on the degree of grafting (DG) was investigated. The graft polymerization of NVP was confirmed by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS). A contact angle goniometry was used to test water contact angle (WCA) of original PPNWF and modified samples. The in vitro blood compatibility, including hemolysis, protein adsorption, platelet adhesion and activated partial thromboplastin time (APTT) of tested specimens, was evaluated. The results demonstrated that the hemocompatibility of PPNWF was improved via graft polymerization of NVP.

  4. X-irradiation removes endogenous primordial germ cells (PGCs) and increases germline transmission of donor PGCs in chimeric chickens.

    PubMed

    Nakamura, Yoshiaki; Usui, Fumitake; Miyahara, Daichi; Mori, Takafumi; Ono, Tamao; Kagami, Hiroshi; Takeda, Kumiko; Nirasawa, Keijiro; Tagami, Takahiro

    2012-01-01

    Primordial germ cells (PGCs) are embryonic precursors of germline cells with potential applications in genetic conservation, transgenic animal production and germline stem cell research. These lines of research would benefit from improved germline transmission of transplanted PGCs in chimeric chickens. We therefore evaluated the effects of pretransplant X-irradiation of recipient embryos on the efficacy of germline transmission of donor PGCs in chimeric chickens. Intact chicken eggs were exposed to X-ray doses of 3, 6 and 9 Gy (dose rate = 0.12 Gy/min) after 52 h of incubation. There was no significant difference in hatching rate between the 3-Gy-irradiated group and the nonirradiated control group (40.0 vs. 69.6%), but the hatching rate in the 6-Gy-irradiated group (28.6%) was significantly lower than in the control group (P<0.05). No embryos irradiated with 9 Gy of X-rays survived to hatching. X-irradiation significantly reduced the number of endogenous PGCs in the embryonic gonads at stage 27 in a dose-dependent manner compared with nonirradiated controls. The numbers of endogenous PGCs in the 3-, 6- and 9-Gy-irradiated groups were 21.0, 9.6 and 4.6% of the nonirradiated control numbers, respectively. Sets of 100 donor PGCs were subsequently transferred intravascularly into embryos irradiated with 3 Gy X-rays and nonirradiated control embryos. Genetic cross-test analysis revealed that the germline transmission rate in the 3-Gy-irradiated group was significantly higher than in the control group (27.5 vs. 5.6%; P<0.05). In conclusion, X-irradiation reduced the number of endogenous PGCs and increased the germline transmission of transferred PGCs in chimeric chickens.

  5. Craniofacial Bone Grafting: Wolff's Law Revisited

    PubMed Central

    Oppenheimer, Adam J.; Tong, Lawrence; Buchman, Steven R.

    2008-01-01

    Bone grafts are used for the reconstruction of congenital and acquired deformities of the facial skeleton and, as such, comprise a vital component of the craniofacial surgeon's armamentarium. A thorough understanding of bone graft physiology and the factors that affect graft behavior is therefore essential in developing a more intelligent use of bone grafts in clinical practice. This article presents a review of the basic physiology of bone grafting along with a survey of pertinent concepts and current research. The factors responsible for bone graft survival are emphasized. PMID:22110789

  6. Modification of LDPE molecular structure by gamma irradiation for bioapplications

    NASA Astrophysics Data System (ADS)

    Ferreira, L. M.; Falcão, A. N.; Gil, M. H.

    2005-07-01

    The surface properties of low-density polyethylene (LDPE) can be modified by the grafting of 2-hydroxyethyl methacrylate (HEMA). This was done aiming at the production of new materials suitable for bioapplications. Samples with different monomer concentrations were prepared from LDPE particles by gamma irradiation, following different irradiation protocols, including irradiation in presence and absence of air. The samples were characterized by thermal analysis techniques (DSC and TGA) and by Fourier transform infrared spectroscopy (FTIR). The results obtained show a decrease in the crystallinity of the supporting matrix for copolymers with high yields of grafting. However, the new materials prepared maintain good structural order resulting from the protective effect of polyHEMA grafted onto LDPE backbone. These effects can improve the diffusion of other species deeper inside the matrix and increase the material hydrophilicity. The studies performed made possible the selection of experimental protocols adequate for the production of new copolymeric materials with high grafting yield. These were used in the production of new LDPE films with enhanced hydrophilic properties.

  7. Phytosanitary Irradiation

    PubMed Central

    Hallman, Guy J.; Blackburn, Carl M.

    2016-01-01

    Phytosanitary treatments disinfest traded commodities of potential quarantine pests. Phytosanitary irradiation (PI) treatments use ionizing radiation to accomplish this, and, since their international commercial debut in 2004, the use of this technology has increased by ~10% annually. Generic PI treatments (one dose is used for a group of pests and/or commodities, although not all have been tested for efficacy) are used in virtually all commercial PI treatments, and new generic PI doses are proposed, such as 300 Gy, for all insects except pupae and adult Lepidoptera (moths). Fresh fruits and vegetables tolerate PI better than any other broadly used treatment. Advances that would help facilitate the use of PI include streamlining the approval process, making the technology more accessible to potential users, lowering doses and broadening their coverage, and solving potential issues related to factors that might affect efficacy. PMID:28231103

  8. Propensity Score-Based Survival Benefit of Simultaneous Liver-Kidney Transplant over Liver Transplant Alone for Recipients with Pre-Transplant Renal Dysfunction

    PubMed Central

    Sharma, Pratima; Shu, Xu; Schaubel, Douglas E.; Sung, Randall S.; Magee, John C.

    2015-01-01

    Survival benefit of simultaneous liver-kidney transplant (SLKT) over liver transplant alone (LTA) is unclear from the current literature. Additionally, the role of donor kidney quality, measured by kidney donor risk index (KDRI), in survival benefit of SLKT is not studied. We compared survival benefit after SLKT and LTA among recipients with similar pre-transplant renal dysfunction using novel methodology, specifically with respect to survival probability and area under the survival curve by dialysis status and KDRI. Methods Data were obtained from the Scientific Registry of Transplant Recipients. The study cohort included patients with pre-LT renal dysfunction who were waitlisted and received either a SLKT (n=1,326) or a LTA (n=4,283) between 3/1/02–12/31/09. Inverse Probability of Treatment Weighted (IPTW) – SLKT and LTA survival curves, along with the 5-year area under the survival curve were computed by dialysis status at transplant. The difference in the area under the curve represents the average additional survival time gained via SLKT over LTA. Results For patients not on dialysis, SLKT resulted in a significant 3.7 month gain in 5-year mean post-transplant survival time. The decrease in mortality rate differs significantly by KDRI, and an estimated 76% of SLKT recipients received a kidney with KDRI sufficiently low for mortality. The mortality decrease for SLKT was concentrated in the first year post-transplant. The difference between SLK and LTA 5-year mean post-transplant survival time was 1.4 months and non-significant for patients not on dialysis. Conclusion The propensity score-adjusted survival among SLKT and LTA recipients was similar for those who were dialysis at LT. Although statistically significant, the survival advantage of SLKT over LTA was of marginal clinical significance among patients not on dialysis; and occurred only if the donor kidney was of sufficient quality. These results should be considered in the ongoing debate regarding the

  9. Anterior Cruciate Ligament Graft Choices

    PubMed Central

    Macaulay, Alec A.; Perfetti, Dean C.; Levine, William N.

    2012-01-01

    Context: Reconstruction of the anterior cruciate ligament (ACL) is a common surgical procedure; however, there is no consensus to what the best graft option is to replace the injured ACL. The main options available consist of allografts and autografts, which include patellar tendon, hamstring tendon, and quadriceps tendon autografts. Evidence Acquisition: The PubMed database was searched in August 2010 for English-language articles pertaining to ACL grafts. Results: Postoperative outcome variables were analyzed to determine similarities and differences among the different graft options. These variables include stability, strength, function, return to sports, patient satisfaction, complications, and cost. Conclusions: Both allografts and the 3 main options for autografts can provide excellent results in ACL reconstruction and lead to a high percentage of satisfied patients. However, differences exist among the graft choices. Both the similarities and the differences are important to discuss with a patient who will be undergoing ACL reconstruction so that he or she has the best information available when making a choice of graft. PMID:23016071

  10. Prognostic pre-transplant factors in myelodysplastic syndromes primarily treated by high dose allogeneic hematopoietic stem cell transplantation: a retrospective study of the MDS subcommittee of the CMWP of the EBMT.

    PubMed

    Cremers, E M P; van Biezen, A; de Wreede, L C; Scholten, M; Vitek, A; Finke, J; Platzbecker, U; Beelen, D; Schwerdtfeger, R; Volin, L; Harhalakis, N; Blijlevens, N; Nagler, A; Kröger, N; de Witte, T

    2016-12-01

    Many pre-transplant factors are known to influence the outcome of allogeneic stem cell transplantation (SCT) treatment in myelodysplastic syndromes (MDS). However, patient cohorts are often heterogeneous by disease stage and treatment modalities, which complicates interpretation of the results. This study aimed to obtain a homogeneous patient cohort by including only de novo MDS patients who received upfront allogeneic SCT after standard high dose myelo-ablative conditioning. The effect of pre-transplant factors such as age, disease stage, transfusions, iron parameters and comorbidity on overall survival (OS), non-relapse mortality (NRM), and relapse incidence (RI) was evaluated in 201 patients. In this cohort, characterized by low comorbidity and a short interval between diagnosis and transplantation, NRM was the most determinant factor for survival after SCT (47 % after 2-year follow-up). WHO classification and transfusion burden were the only modalities with a significant impact on overall survival after SCT. Estimated hazard ratios (HR) showed a strongly increased risk of death, NRM and RI, in patients with a high transfusion-burden (HR 1.99; P = 0.006, HR of 1.89; P = 0.03 and HR 2.67; P = 0.03). The HR's for ferritin level and comorbidity were not significantly increased.

  11. Plant grafting: new mechanisms, evolutionary implications

    PubMed Central

    Goldschmidt, Eliezer E.

    2014-01-01

    Grafting, an old plant propagation practice, is still widely used with fruit trees and in recent decades also with vegetables. Taxonomic proximity is a general prerequisite for successful graft-take and long-term survival of the grafted, composite plant. However, the mechanisms underlying interspecific graft incompatibility are as yet insufficiently understood. Hormonal signals, auxin in particular, are believed to play an important role in the wound healing and vascular regeneration within the graft union zone. Incomplete and convoluted vascular connections impede the vital upward and downward whole plant transfer routes. Long-distance protein, mRNA and small RNA graft-transmissible signals currently emerge as novel mechanisms which regulate nutritional and developmental root/top relations and may play a pivotal role in grafting physiology. Grafting also has significant pathogenic projections. On one hand, stock to scion mechanical contact enables the spread of diseases, even without a complete graft union. But, on the other hand, grafting onto resistant rootstocks serves as a principal tool in the management of fruit tree plagues and vegetable soil-borne diseases. The ‘graft hybrid’ historic controversy has not yet been resolved. Recent evidence suggests that epigenetic modification of DNA-methylation patterns may account for certain graft-transformation phenomena. Root grafting is a wide spread natural phenomenon; both intraspecific and interspecific root grafts have been recorded. Root grafts have an evolutionary role in the survival of storm-hit forest stands as well as in the spread of devastating diseases. A more fundamental evolutionary role is hinted by recent findings that demonstrate plastid and nuclear genome transfer between distinct Nicotiana species in the graft union zone, within a tissue culture system. This has led to the formation of alloploid cells that, under laboratory conditions, gave rise to a novel, alloploid Nicotiana species

  12. Irradiation as a safety procedure in tissue banking.

    PubMed

    Dziedzic-Goclawska, Anna; Kaminski, Artur; Uhrynowska-Tyszkiewicz, Izabela; Stachowicz, Wacław

    2005-01-01

    The Central Tissue Bank in Warsaw was established in 1963 and since then ionising radiation has been routinely applied to sterilise tissue grafts. Connective tissue grafts such as bone, cartilage, tendons, sclera, pericardium, skin, acellular dermis and amnion irradiated with a dose of 35 kGy in a (60)Co source and/or with an electron beam 10 MeV accelerator are prepared in our Tissue Bank and two other multi-tissue banks operating in Poland. Over 250,000 radiation-sterilised tissue grafts have been prepared and used in hospitals throughout Poland and no infectious disease transmission or other adverse post-transplantation reactions have been reported up to today. It should be kept in mind however, that high doses of ionising radiation can evoke numerous chemical and physical changes that may affect the biological quality of tissue allografts. Therefore, interdisciplinary research has been undertaken at the Central Tissue Bank in Warsaw to establish the origin and stability of free radicals and other paramagnetic entities induced by irradiation in bone. The effects of various preservation procedures (e.g. lyophilisation, deep-freezing) and irradiation conditions (doses, temperature of irradiation) on the osteoinductive potential and mechanical properties of bone and on the degradation of collagen, a major constituent of all connective tissue grafts, have been also studied. The results of these studies indicate that radiation-induced changes can be diminished by modification of tissue preservation methods and that, to some extent, it is possible to reduce undesired radiation-induced damage to the tissue grafts.

  13. A hydrated phospholipid polymer-grafted layer prevents lipid-related oxidative degradation of cross-linked polyethylene.

    PubMed

    Kyomoto, Masayuki; Moro, Toru; Yamane, Shihori; Takatori, Yoshio; Tanaka, Sakae; Ishihara, Kazuhiko

    2017-01-01

    The surface and substrate of a cross-linked polyethylene (CLPE) liner are designed to achieve resistance against oxidative degradation in the construction of hip joint replacements. In this study, we aimed to evaluate the oxidative degradation caused by lipid absorption of a highly hydrophilic nanometer-scaled thickness layer prepared by grafting a poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) layer and a high-dose gamma-ray irradiated CLPE with vitamin E blending (HD-CLPE[VE]). The HD-CLPE(VE) and PMPC-grafted HD-CLPE(VE) exhibited extremely high oxidation resistance regardless of lipid absorption, even though residual-free radical levels were detectable. The water wettability of the PMPC-grafted CLPE and PMPC-grafted HD-CLPE(VE) surfaces was considerably greater than that of untreated surfaces. The hydrated PMPC-grafted layer also exhibited extremely low solubility for squalene. Lipids such as squalene and cholesterol esters diminished the oxidation resistance of CLPE despite the vitamin E improvement. Notably, the PMPC-grafted surface was resistant to lipid absorption and diffusion as well as subsequent lipid-related oxidative degradation, likely because of the presence of the hydrated PMPC-grafted layer. Together, these results provide preliminary evidence that the resistance against lipid absorption and diffusion of a hydrated PMPC-grafted layer might positively affect the extent of resistance to the in vivo oxidation of orthopedic implants.

  14. Highly hydrophilic ultra-high molecular weight polyethylene powder and film prepared by radiation grafting of acrylic acid

    NASA Astrophysics Data System (ADS)

    Wang, Honglong.; Xu, Lu.; Li, Rong.; Pang, Lijuan.; Hu, Jiangtao.; Wang, Mouhua.; Wu, Guozhong.

    2016-09-01

    The surface properties of ultra-high molecular weight polyethylene (UHMWPE) are very important for its use in engineering or composites. In this work, hydrophilic UHMWPE powder and film were prepared by γ-ray pre-irradiation grafting of acrylic acid (AA) and further neutralization with sodium hydroxide solution. Variations in the chemical structure, grafting yield and hydrophilicity were investigated and compared. FT-IR and XPS analysis results showed that AA was successfully grafted onto UHMWPE powder and film; the powder was more suitable for the grafting reaction in 1 wt% AA solution than the film. Given a dose of 300 kGy, the grafting yield of AA was ∼5.7% for the powder but ∼0.8% for the film under identical conditions. Radiation grafting of a small amount of AA significantly improved the hydrophilicity of UHMWPE. The water contact angle of the UHMWPE-g-PAA powder with a grafting yield of AA at ∼5.7% decreased from 110.2° to 68.2°. Moreover, the grafting powder (UHMWPE-g-PAA) exhibited good dispersion ability in water.

  15. Specific and nonspecific T-cell-mediated suppression of antihost immune reactivity in graft-versus-host reaction

    SciTech Connect

    Bril, H.; Molendijk-Lok, B.D.; Benner, R.

    1983-09-01

    Intravenous immunization of mice with irradiated (2000 rads) allogeneic lymphoid cells induces the generation of suppressor T cells. Such suppressor T cells are capable of suppressing the antihost immune reactivity during acute and delayed graft-versus-host reactions. These suppressor T cells are strictly antigen-specific as far as their activation is concerned, but also suppress the reaction against unrelated antigens presented by the irradiated host.

  16. Radiation graft copolymerization of butyl methacrylate and acrylamide onto low density polyethylene and polypropylene films, and its application in wastewater treatment

    NASA Astrophysics Data System (ADS)

    Abdel Ghaffar, A. M.; El-Arnaouty, M. B.; Aboulfotouh, Maysara E.; Taher, N. H.; Taha, Ahmed A.

    2014-09-01

    Butyl methacrylate and acrylamide (BMA/AAm) comonomers were grafted onto low-density polyethylene (LDPE) and polypropylene (PP) films using the mutual gamma radiation grafting technique. The influences of grafting conditions such as solvent, monomer concentration, monomer composition, and irradiation dose on the grafting yield were determined. It was found that using dimethyl formamide as a solvent enhanced the copolymerization process. The grafting yield increases as the comonomer concentration increases up to 60%. Also it was found that the degree of grafting of BMA/AAm onto both LDPE and PP films increases as the AAm content increases till an optimum value at 50:50 wt%. The grafting yield of the comonomers was found to increase with increase in the radiation dose. It was observed that the degree of grafting of polyethylene films is higher than that of polypropylene (PP) films at the same conditions. Some selected properties of the graft copolymers, such as water uptake and thermal properties, were determined using thermogravimetric analysis. The morphology and structure of the grafted films were investigated using scanning electron microscopy, infra-red, and X-ray diffraction. Improvement in such properties of the prepared copolymers was observed which offers possible uses in some practical applications such as the removal of some heavy metals from wastewater. It was found that the maximum metal uptake by the copolymer followed the order Cu2+>Co2+>Ni2+ ions.

  17. Gamma-Irradiated Sterile Cornea for Use in Corneal Transplants in a Rabbit Model

    PubMed Central

    Yoshida, Junko; Heflin, Thomas; Zambrano, Andrea; Pan, Qing; Meng, Huan; Wang, Jiangxia; Stark, Walter J.; Daoud, Yassine J.

    2015-01-01

    Purpose: Gamma irradiated corneas in which the donor keratocytes and endothelial cells are eliminated are effective as corneal lamellar and glaucoma patch grafts. In addition, gamma irradiation causes collagen cross inking, which stiffens collagen fibrils. This study evaluated gamma irradiated corneas for use in corneal transplantations in a rabbit model comparing graft clarity, corneal neovascularization, and edema. Methods: Penetrating keratoplasty was performed on rabbits using four types of corneal grafts: Fresh cornea with endothelium, gamma irradiated cornea, cryopreserved cornea, and fresh cornea without endothelium. Slit lamp examination was performed at postoperative week (POW) one, two, and four. Corneal clarity, edema, and vascularization were graded. Confocal microscopy and histopathological evaluation were performed. A P < 0.05 was statistically significant. Results: For all postoperative examinations, the corneal clarity and edema were statistically significantly better in eyes that received fresh cornea with endothelium compared to the other three groups (P < 0.05). At POW 1, gamma irradiated cornea scored better than the cryopreserved and fresh cornea without endothelium groups in clarity (0.9 vs. 1.5 and 2.6, respectively), and edema (0.6 vs. 0.8 and 2.0, respectively). The gamma irradiated corneas, cryopreserved corneas and the fresh corneas without endothelium, developed haze and edema after POW 2. Gamma irradiated cornea remained statistically significantly clearer than cryopreserved and fresh cornea without endothelium during the observation period (P < 0.05). Histopathology indicated an absence of keratocytes in gamma irradiated cornea. Conclusion: Gamma irradiated corneas remained clearer and thinner than the cryopreserved cornea and fresh cornea without endothelium. However, this outcome is transient. Gamma irradiated corneas are useful for lamellar and patch grafts, but cannot be used for penetrating keratoplasty. PMID:26180475

  18. Types of Coronary Artery Bypass Grafting

    MedlinePlus

    ... from the NHLBI on Twitter. Types of Coronary Artery Bypass Grafting There are several types of coronary ... for you based on your needs. Traditional Coronary Artery Bypass Grafting Traditional CABG is used when at ...

  19. Who Needs Coronary Artery Bypass Grafting?

    MedlinePlus

    ... from the NHLBI on Twitter. Who Needs Coronary Artery Bypass Grafting? Coronary artery bypass grafting (CABG) is used to treat people ... or after a heart attack to treat blocked arteries. Your doctor may recommend CABG if other treatments, ...

  20. Costal Cartilage Grafts in Rhinoplasty.

    PubMed

    Fedok, Fred G

    2016-01-01

    Cartilage grafts are regularly used in rhinoplasty. Septal and auricular donor sites are commonly used. Many situations compel the surgeon to use other alternative donor sites, including revision rhinoplasty and trauma. Many patients have a small amount of native septal cartilage and are unable to provide adequate septal cartilage to be used for frequently performed rhinoplasty maneuvers. The rib cage provides an enormous reserve of costal cartilage that can be carved into a variety of necessary grafts. A description of the technique of harvesting costal cartilage, a review of complications and management, and illustrative cases examples are included.

  1. Modification of fiber properties through grafting of acrylonitrile to rayon by chemical and radiation methods.

    PubMed

    Kaur, Inderjeet; Sharma, Neelam; Kumari, Vandna

    2013-11-01

    Fibrous properties of rayon has been modified through synthesis of graft copolymers of rayon with acrylonitrile (AN) by chemical method using ceric ammonium nitrate (CAN/HNO3) as a redox initiator and gamma radiation mutual method. Percentage of grafting (Pg) was determined as a function of initiator concentration, monomer concentration, irradiation dose, temperature, time of reaction and the amount of water. Maximum percentage of grafting (160.01%) using CAN/HNO3 was obtained at [CAN] = 22.80 × 10(-3) mol/L, [HNO3] = 112.68 × 10(-2) mol/L and [AN] = 114.49 × 10(-2) mol/L in 20 mL of water at 45 °C within 120 min while in case of gamma radiation method, maximum Pg (90.24%) was obtained at an optimum concentration of AN of 76.32 × 10(-2) mol/L using 10 mL of water at room temperature with total dose exposure of 3.456 kGy/h. The grafted fiber was characterized by FTIR, SEM, TGA and XRD studies. Swelling behavior of grafted rayon in different solvents such as water, methanol, ethanol, DMF and acetone was studied and compared with the unmodified rayon. Dyeing behavior of the grafted fiber was also investigated.

  2. Biotribological properties of UHMWPE grafted with AA under lubrication as artificial joint.

    PubMed

    Deng, Yaling; Xiong, Dangsheng; Wang, Kun

    2013-09-01

    Osteolysis caused by wear particles from polyethylene in the artificial hip joints is a serious issue. In order to endow the low friction and wear of the bearing surface of ultra-high molecular weight polyethylene (UHMWPE) artificial joint for a longer term, hydrophilic acrylic acid (AA) was grafted on UHMWPE powders with the method of ultraviolet irradiation and then the modified powders were hot pressed. The tribological properties of modified UHMWPE sliding against CoCrMo metallic plate on reciprocating tribometer under calf serum, saline and distilled water lubrication during a long-term friction were investigated. The measurement of Fourier-transform infrared spectroscopy indicates that AA is successfully grafted on the surface of UHMWPE powders by photo-induced graft polymerization. Contact angles of UHMWPE are decreased from 83° to 35° by grafting and the surface wettability is effectively improved. The tensile strength of modified sample decreases. The friction coefficient and wear rate of UHMWPE-g-PAA under calf serum, saline and distilled water lubrication are lower than that of untreated UHMWPE. With the increase of grafting ratio, the wear rate of UHMWPE-g-PAA decreases firstly and then increases. The modified UHMWPE with grafting ratio of 3.5 % has the lowest wear rate, which is just quarter of the untreated UHMWPE. The hydrated PAA polymer brushes enclosed in the UHMWPE bulk material provide continuous lubrication during long term sliding.

  3. Crystal structure and mechanical properties of UHMWPE-g-PMA fiber prepared by radiation grafting

    NASA Astrophysics Data System (ADS)

    Xing, Zhe; Wang, Mouhua; liu, Weihua; Hu, Jiangtao; Wu, Guozhong

    2013-05-01

    Methyl acrylate (MA) monomer was grafted onto ultra-high molecular weight polyethylene (UHMWPE) fibers by γ-ray pre-irradiation induced graft polymerization. The grafting of MA on UHMWPE fiber was confirmed by thermogravimetric analysis and Fourier-transform infrared spectroscopy. The degree of grafting (DG) increased with an increase in absorbed dose and reached a significantly high value (approximately 200%) at 100 kGy. Scanning electron microscopy analysis revealed that the surface of the UHMWPE-g-PMA fibers was covered by the MA grafting layer and became rough. The monoclinic crystalline and orientated intermediate phases were disordered by the grafting chains such that degree of orientation declined gradually with increasing DG. The tensile strength of UHMWPE-g-PMA fiber decreased with increasing dose but was independent of DG, whereas the fiber modulus declined with DG. UHMWPE-g-PMA fiber that possesses desirable mechanical properties could be obtained at a dose of less than 10 kGy.

  4. Hydrolyzed polyacrylamide grafted maize starch based microbeads: application in pH responsive drug delivery.

    PubMed

    Setty, C Mallikarjuna; Deshmukh, Anand S; Badiger, Aravind M

    2014-09-01

    The present study details the synthesis, characterization and pharmaceutical application of hydrolysed polyacrylamide grafted maize starch (HPam-g-MS) as promising polymeric material for the development of pH responsive microbeads. Different grades of graft copolymer were synthesized by changing the net microwave irradiation time, while keeping all other factors constant. Acute oral toxicity study performed in rodents ensured the bio-safety of graft copolymer for clinical application. Various batches of aceclofenac loaded microbeads were prepared by ionic gelation method using synthesized graft copolymers and evaluated for formulation parameters. FTIR spectroscopy confirmed the chemical compatibility between drug and graft copolymer. Results of in vitro release study (USP type-II) carried out in two different pH media (pH 1.2 acid buffer and pH 7.4 phosphate buffer) showed that release rate of drug from developed microbeads was a function of both: (a) surrounding pH and (b) the matrix composition. The drug release was relatively higher at alkaline pH as compared to acidic pH and this feature is desirable from viewpoint of site specific drug delivery. A direct correlation was observed between percentage grafting and microbeads performance and it presents a scope for further research on application and optimization of HPam-g-MS based microbeads as drug delivery carriers.

  5. Could mucin 16 and colony-stimulating factor 2-receptor beta possible graft versus host disease biomarkers? Medical hypotheses.

    PubMed

    Souza, Milena Monteiro de; de Paula, Fabiana Martins; Hsieh, Ricardo; Macedo, Maria Cristina Martins Almeida; Corral, Marcelo Andreetta; Nunes, Thaís Borguezan; De Paula, Fernanda; Lourenço, Silvia Vanessa

    2017-03-01

    Graft versus host disease (GVHD) occurs after bone marrow transplantation and is one of the most important causes of death worldwide. Reviews demonstrated GVHD patients with involvement of various tissues and organs, such as salivary glands. The diagnosis of acute GVHD has been the biopsies and the histopathologic evaluation of tissue from an involved organ. These procedures are invasive. Saliva proteins as possible biomarker for GVHD could facilitate the management and diagnosis accuracy. For support the proposed hypotheses, in this pilot study we collected whole saliva samples from patients with undergoing allogeneic hematopoietic cell transplantation (HCT) and from healthy subjects. Samples were collected prospectively between pre-transplant, thirty days, one hundred and, two hundred days after transplant. The proteomic profile was analyzed using SDS-PAGE and LCMS-ESI-IT-TOF mass spectrometry. The relevant personal data, past medical history were also recorded. The most relevant proteins found exclusively in GVHD patients were: CSF2RB, Protocadherin (Pcdh) Fat 2 precursor, protein capicua homolog isoform CIC-S, MUC16 and RGPD8_HUMAN RANBP2. This study aims to conduct an initial evaluation of the possible presence of such biomarkers in saliva from GVHD patients, and suggested a potential application of proteomics analysis as a alternative method to diagnose GVHD.

  6. Synthesis of polytetrafluoroethylene based olefinic copolymer by gamma radiation grafting

    NASA Astrophysics Data System (ADS)

    Ferreto, H. F. R.; Lima, L. F. C. P.; Parra, D. F.; Zaia, V.; Lugão, A. B.

    2007-12-01

    High speed extrusion of linear low density polyethylene (LLDPE) is limited by processes shortcoming known as 'melt fracture' and 'sharkskin', which are surface defect of the extruded polymer. This defect results in a product with a rough surface that lacks luster and with poor surface properties. The fluoropolymer processing additives are used to eliminate the surface defect by coating the die wall and inducing slip at the coated fluoropolymer surface/LLDPE interface. The aim of this study was to obtain a recycled polytetrafluoroethylene polymer grafted with an olefin that could improve the extrudability of the LLDPE. The copolymer was obtained by irradiating recycled PTFE in an inert atmosphere followed by grafting an olefinic monomer the polymeric matrix (PTFE). After a certain time of contact, the copolymer was heat treated to allow recombination and elimination of the radicals, both in a reactive and/or inert atmosphere. The olefinic monomer used was 1,3-butadiene. The 1,3-butadiene monomer was found to be more effective with respect to grafting. The specimens were studied using Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and differential thermogravimetry (DTG). The obtained copolymer (0.2-2.0 wt%) was mixed with LLDPE. The rheological properties of the mixture were determined with a torque rheometer. The results indicated that the developed process rendered a copolymer which when added to LLDPE, improved the extrusion process and eliminated the defect 'melt fracture'.

  7. [Transfusion associated graft versus host disease following cardiovascular surgery].

    PubMed

    Aybey, Bekir; Coşkun, Diler; Aytaç, Jale

    2006-01-01

    In this report, a case of transfusion-associated graft versus host disease that developed following coronary arter bypass grafting and mitral annuloplasty operations, has been presented. The diagnosis of 62 year-old male patient was based on the presence of typical findings as fever, liver function disorders, skin rash and hypoplastic bone marrow findings that began ten days after the operation; with the exclusion of other pathologies (e.g. drug eruptions, viral infections, septicemia, scalded skin syndrome and toxic epidermal necrolysis) and histopathological findings of skin biopsy. There was a history of five units of blood transfusion of which one was from a close relative. The blood from the relative was thought to be responsible for the disease. With this case, we wanted to emphasize once more that transfusion of the blood of a relative must be avoided in patients who have undergone major operations such as cardiovascular surgery. The irradiation of these bloods before transfusion may be effective to prevent graft versus host disease.

  8. Synthesis of arsenic graft adsorbents in pilot scale

    NASA Astrophysics Data System (ADS)

    Hoshina, Hiroyuki; Kasai, Noboru; Shibata, Takuya; Aketagawa, Yasushi; Takahashi, Makikatsu; Yoshii, Akihiro; Tsunoda, Yasuhiko; Seko, Noriaki

    2012-08-01

    Synthesis of arsenic (As) adsorbents in pilot scale was carried out with a synthesizing apparatus by radiation-induced graft polymerization of 2-hydroxyethyl methacrylate phosphoric acid monomer (PA), which consists of phosphoric acid mono- (50%) and di- (50%) ethyl methacrylate esters onto a nonwoven cotton fabric (NCF), and following chemical modification by contact with a zirconium (Zr) solution. The apparatus which was equipped with reaction tanks, a washing tank and a pump can produce up to 0.3 m×14 m size of the As(V) adsorbent in one reaction. A degree of grafting of 150% was obtained at an irradiation dose of 20 kGy with 5% of PA solution mixed with deionized water for 1 h at 40 °C. Finally, after Zr(IV) was loaded onto a NCF with 5 mmol/L of Zr(IV) solution, the graft adsorbent for the removal of As(V) was achieved in pilot-scale. The adsorbent which was synthesized in pilot scale was evaluated in batch mode adsorption with 1 ppm (mg/l) of As(V) solution for 2 h at room temperature. As a result, the adsorption capacity for As(V) was 0.02 mmol/g-adsorbent.

  9. Stimulation of post-traumatic regeneration of skeletal muscles of old rats after x-ray irradiation

    SciTech Connect

    Bulyakova, N.V.; Popova, M.F.

    1987-09-01

    The authors seek a method of stimulating restorative processes in irradiated muscles of old animals. Rats were used in the experiments. Different series of experiments were performed, including complete transverse section of the gastrocnemius muscle after local x-ray irradiation, and laser therapy of the transversly divided gastrocnemius muscle. Post-traumatic regeneration of the gastrocnemius muscle of old rats is illustrated schematically. The experimental data showed that pulsed laser therapy or grafting of minced unirradiated muscle tissue can largely restore the regenerative capacity of the gastrocnemius muscle of old rats when depressed by x-ray irradiation, but the method of grafting minced unirradiated muscle tissue was more effective.

  10. Organosiloxane-grafted natural polymer coatings

    DOEpatents

    Sugama, Toshifumi

    1998-01-01

    A new family of polysaccharide graft polymers are provided as corrosion resistant coatings having antimicrobial properties which are useful on light metals such as aluminum, magnesium, zinc, steel and their alloys. Methods of making the polysaccharide graft polymers are also included. The methods of making the polysaccharide graft polymers involve reacting a polysaccharide source with an antimicrobial agent under conditions of hydrolysis-condensation.

  11. Grafting efficiency of synthetic polymers onto biomaterials: a comparative study of grafting-from versus grafting-to.

    PubMed

    Hansson, Susanne; Trouillet, Vanessa; Tischer, Thomas; Goldmann, Anja S; Carlmark, Anna; Barner-Kowollik, Christopher; Malmström, Eva

    2013-01-14

    In the present study, the two grafting techniques grafting-from - by activators regenerated by electron transfer atom transfer radical polymerization (ARGET ATRP) - and grafting-to - by copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) - were systematically compared, employing cellulose as a substrate. In order to obtain a meaningful comparison, it is crucial that the graft lengths of the polymers that are grafted from and to the substrates are essentially identical. Herein, this was achieved by utilizing the free polymer formed in parallel to the grafting-from reaction as the polymer for the grafting-to reaction. Four graft lengths were investigated, and the molar masses of the four free polymers (21 ≤ M(n) ≤ 100 kDa; 1.07 ≤ Đ(M) ≤ 1.26), i.e. the polymers subsequently employed in the grafting-to reaction, were shown to be in the same range as the molar masses of the polymers grafted from the surface (23 ≤ M(n) ≤ 87 kDa; 1.08 ≤ Đ(M) ≤ 1.31). The molecular weights of the chains grafted from the surface were established after cleavage from the cellulose substrates via size exclusion chromatography (SEC). High-resolution Fourier transform infrared microscopy (FT-IRM) was employed as an efficient tool to study the spatial distribution of the polymer content on the grafted substrates. In addition, the functionalized substrates were analyzed by X-ray photoelectron spectroscopy (XPS), contact angle (CA) measurements, and field-emission scanning electron microscopy (FE-SEM). For cellulose substrates modified via the grafting-from approach, the content of polymer on the surfaces increased with increasing graft length, confirming the possibility to tailor not only the length of the polymer grafts but also the polymeric content on the surface. In comparison, for the grafting-to reaction, the grafted content could not be controlled by varying the length of the preformed polymer: the polymer content was essentially the same for the four graft lengths

  12. Use of Irradiated Foods

    NASA Technical Reports Server (NTRS)

    Brynjolfsson, A.

    1985-01-01

    The safety of irradiated foods is reviewed. Guidelines and regulations for processing irradiated foods are considered. The radiolytic products formed in food when it is irradiated and its wholesomeness is discussed. It is concluded that food irradiation processing is not a panacea for all problems in food processing but when properly used will serve the space station well.

  13. Polyether-polyester graft copolymer

    NASA Technical Reports Server (NTRS)

    Bell, Vernon L. (Inventor)

    1987-01-01

    Described is a polyether graft polymer having improved solvent resistance and crystalline thermally reversible crosslinks. The copolymer is prepared by a novel process of anionic copolymerization. These polymers exhibit good solvent resistance and are well suited for aircraft parts. Previous aromatic polyethers, also known as polyphenylene oxides, have certain deficiencies which detract from their usefulness. These commercial polymers are often soluble in common solvents including the halocarbon and aromatic hydrocarbon types of paint thinners and removers. This limitation prevents the use of these polyethers in structural articles requiring frequent painting. In addition, the most popular commercially available polyether is a very high melting plastic. This makes it considerably more difficult to fabricate finished parts from this material. These problems are solved by providing an aromatic polyether graft copolymer with improved solvent resistance and crystalline thermally reversible crosslinks. The graft copolymer is formed by converting the carboxyl groups of a carboxylated polyphenylene oxide polymer to ionic carbonyl groups in a suitable solvent, reacting pivalolactone with the dissolved polymer, and adding acid to the solution to produce the graft copolymer.

  14. Acrylic polymer-grafted polypropylene sutures for covalent immobilization or reversible adsorption of vancomycin.

    PubMed

    García-Vargas, M; González-Chomón, C; Magariños, B; Concheiro, A; Alvarez-Lorenzo, C; Bucio, E

    2014-01-30

    Glycidyl methacrylate (GMA) and acrylic acid (AAc) were separately grafted onto polypropylene (PP) monofilament sutures by means of pre-irradiation using a (60)Co γ-source, with the purpose of loading vancomycin via (i) covalent immobilization through the glycidyl groups of GMA and (ii) ionic interaction with AAc moieties. The effect of absorbed radiation dose, monomer concentration, temperature and reaction time on the grafting degree was evaluated in detail. GMA grafting ranged from 25% to 800% while the grafting yield of AAc onto PP could be tuned between 9% and 454%, at doses from 5 to 50 kGy and a dose rate 13.7 kGy/h. Grafting of GMA or AAc decreased the decomposition temperature and made the sutures swellable to a certain extent. GMA grafting led to a continuous, smooth and thick coating, which was suitable for immobilization of up to 1.9 μg vancomycin per gram. The immobilized vancomycin enabled a reduction in the Staphylococcus aureus CFU adhered to the suture surface. On the other hand, dried AAc-functionalized sutures exhibited a rough and cracked surface which was responsible for a minor increase in the coefficient of friction. PP-g-AAc sutures exhibited pH-dependent swelling and remarkably high capability to host vancomycin (up to 109.9 mg/g), particularly those with an intermediate degree of grafting. Some AAc-functionalized sutures were shown able to inhibit bacterial growth after successive challenges with fresh lawns. Therefore, tuning the yield of grafting of GMA or AAc may enable the preparation of drug-suture combination products that retain or release, respectively, antimicrobial agents.

  15. Immunity of fungal infections alleviated graft reject in liver transplantation compared with non-fungus recipients

    PubMed Central

    Xing, Tonghai; Zhong, Lin; Lin, Lihui; Qiu, Guoqiang; Peng, Zhihai

    2015-01-01

    Objective: To evaluate of the immune tolerance in adult LT recipients with Invasive fungal infections (IFIs). Methods: 109 consecutive LT recipients who received LT were included. Percentage of T subsets (CD4+CD25hiCD127- T cells, CD4+CD25loCD45RA+ T cells, CD4+CD25loCD45RA- and CD4+CD45RA-CD45RO+ T cells populations), levels of cytokines (IL-1b, IL-2, IL-4, IL-6, IL-8, IL-10, IFN-γ, IL-12p70, IL-17, TNF-α, TNF-β and GM-CSF) were detected by FACS and Bioplex in peripheral blood. Biopsy specimens were fixed, monoclonal antibodies against CD4, Foxp3 and IL-17 were applied to the above sections and FISH was performed. Results: The risk of acute rejection was decreased in fungal infected liver transplant recipients comparing with non-fungal infected group. CD4+CD25hiCD127T cell population was increased in peripheral blood and memory CD4+CD45RA-CD45RO+ T cell population decreased. There was significant lower levels observed in naïve CD4+CD25loCD45RA+ and CD4+CD25loCD45RA- T cell populations in fungal infected liver transplant. Moreover, IL-2, IL-6, IL-10 and GM-CSF were decreased. However, no significant difference with IL-4 and IL-8 in serum in two infected LT recipients. Conclusion: The incidence of graft rejection in liver transplantation recipients with fungal infections was lower than the non-fungal group. It is important to assess the risk during pretransplant and postoperation for liver transplantation. PMID:26045766

  16. Allograft tissue irradiation and failure rate after anterior cruciate ligament reconstruction: A systematic review

    PubMed Central

    Dashe, Jesse; Parisien, Robert L; Cusano, Antonio; Curry, Emily J; Bedi, Asheesh; Li, Xinning

    2016-01-01

    AIM: To evaluate whether anterior cruciate ligament (ACL) allograft irradiation is effective for sterility without compromising graft integrity and increasing failure rate. METHODS: A literature search was conducted using PubMed, Cochrane, and Google. The following search terms were used: “Gamma irradiation AND anterior cruciate ligament AND allograft” with a return of 30 items. Filters used included: English language, years 1990-2015. There were 6 hits that were not reviewed, as there were only abstracts available. Another 5 hits were discarded, as they did not pertain to the topic of interest. There were 9 more articles that were excluded: Three studies were performed on animals and 6 studies were meta-analyses. Therefore, a total of 10 articles were applicable to review. RESULTS: There is a delicate dosing crossover where gamma irradiation is both effective for sterility without catastrophically compromising the structural integrity of the graft. Of note, low dose irradiation is considered less than 2.0 Mrad, moderate dose is between 2.1-2.4 Mrad, and high dose is greater than or equal to 2.5 Mrad. Based upon the results of the literature search, the optimal threshold for sterilization was found to be sterilization at less than 2.2 Mrad of gamma irradiation with the important caveat of being performed at low temperatures. The graft selection process also must include thorough donor screening and testing as well as harvesting the tissue in a sterile fashion. Utilization of higher dose (≥ 2.5 Mrad) of irradiation causes greater allograft tissue laxity that results in greater graft failure rate clinically in patients after ACL reconstruction. CONCLUSION: Allograft ACL graft gamma irradiated with less than 2.2 Mrad appears to be a reasonable alternative to autograft for patients above 25 years of age. PMID:27335815

  17. Temperature-responsiveness and biocompatibility of DEGMA/OEGMA radiation-grafted onto PP and LDPE films

    NASA Astrophysics Data System (ADS)

    Ramírez-Jiménez, Alejandro; Alvarez-Lorenzo, Carmen; Concheiro, Angel; Bucio, Emilio

    2014-06-01

    Polypropylene (PP) and low density polyethylene (LDPE) were modified by γ-ray grafting of di(ethylene glycol) methyl ether methacrylate (DEGMA) and oligo (ethylene glycol) methyl ether methacrylate (OEGMA300 or OEGMA475 with Mn 300 and 475 respectively) with different monomer concentrations and mol ratios. The grafting percentage was evaluated as a function of the solvent, irradiation dose, reaction time, temperature, and monomers concentration. The grafted materials were more hydrophilic than the pristine polymers, as observed by contact angle and swelling in water. Temperature-responsive behavior was evaluated using DSC showing transitions between 34 and 48 °C. In vitro hemocompatibility, protein adsorption, cytotoxicity and bacteria adhesion tests were also carried out. Overall, the DEGMA/OEGMA grafting provides hemo and cytocompatible materials that exhibit temperature-responsive hydrophilic features and decreased protein adsorption.

  18. Microwave induced synthesis of graft copolymer of binary vinyl monomer mixtures onto delignified Grewia optiva fibre: Application in dye removal

    NASA Astrophysics Data System (ADS)

    Gupta, Vinod; Pathania, Deepak; Priya, Bhanu; Singha, A. K.; Sharma, Gaurav

    2014-08-01

    Grafting method, through microwave radiation technique is very effective in terms of time consumption, cost effectiveness and environmental friendliness. Via this method, delignified Grewia optiva identified as a waste biomass, was graft copolymerized with methylmethacrylate (MMA) as an principal monomer in a binary mixture of ethyl methacrylate (EMA) and ethyl acrylate (EA) under microwave irradiation (MWR) using ascorbic acid/H2O2 as an initiator system. The concentration of the comonomer was optimized to maximize the graft yield with respect to the primary monomer. Maximum graft yield (86.32%) was found for dGo-poly(MMA-co-EA) binary mixture as compared to other synthesized copolymer. The experimental results inferred that the optimal concentrations for the comonomers to the optimized primary monomer was observed to be 3.19 mol/L×10-1 for EMA and 2.76 mol/L×10-1 for EA. Delignified and graft copolymerized fibre were subjected to evaluation of physicochemical properties such as swelling behaviour and chemical resistance. The synthesized graft copolymers were characterized with Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and X-ray diffraction techniques. Thermal stability of dGo-poly(MMA-co-EA) was found to be more as compared to the delignified Grewia optiva fibre and other graft copolymers. Although the grafting technique was found to decrease percentage crystallinity and crystallinity index among the graft copolymers but there was significant increase in their acid/base and thermal resistance properties. The grafted samples have been explored for the adsorption of hazardous methylene dye from aqueous system.

  19. Surgical Outcomes of Porcine Acellular Dermis Graft in Anophthalmic Socket: Comparison with Oral Mucosa Graft

    PubMed Central

    Teo, Livia; Woo, Young Jun; Kim, Dong Kyu; Kim, Chang Yeom

    2017-01-01

    Purpose We describe our experience with the Permacol graft in anophthalmic socket reconstruction, and compare it to the autologous buccal mucosal graft, emphasizing the postoperative vascularization and contraction of each graft. Methods This was a retrospective comparative study. We measured the time necessary for the graft surface to be completely vascularized, as well as the fornix depth of the conjunctival sac in anophthalmic patients. Results Ten patients underwent Permacol graft reconstruction, with 44 undergoing buccal mucosal graft reconstruction. Seven eyelids (70%) in the Permacol group had a good outcome, with improvement in lower eyelid position and prosthesis retention. Nine out of 10 eyelids (90%) in this group showed complete vascularization of the graft at 2.6 ± 1.9 months postoperatively, while the grafted buccal mucosa was fully vascularized at 1.1 ± 0.3 months postoperatively (p < 0.01). Postoperative fornix depth in the Permacol group was 9.1 ± 2.2 mm, compared to 14.9 ± 4.5 mm in the buccal mucosal graft group (p < 0.01). Mean increases in fornix depth were 33.1% and 67.9% of the mean vertical length of the implanted graft. Conclusions The Permacol graft can be useful as spacer graft material in anophthalmic socket patients. It takes longer to vascularize, and undergoes greater graft shrinkage with time, compared to the buccal mucosal graft. PMID:28243018

  20. Immune mechanisms in organ allograft rejection. V. Pivotal role of the cytotoxic-suppressor T cell subset in the rejection of heart grafts bearing isolated class I disparities in the inbred rat

    SciTech Connect

    Lowry, R.P.; Forbes, R.D.; Blackburn, J.H.; Marghesco, D.M.

    1985-11-01

    The cellular requirements for rejection of heart grafts bearing isolated major histocompatibility complex (MHC) subregion RT1A-encoded class I disparities was assessed by adoptive transfer. Sublethally irradiated (780 rads) (PVG X WF)F1 recipients of irradiated PVG-RT1r1 heart grafts were selectively reconstituted with spleen cells from syngeneic donors previously sensitized with two sequential PVG-RT1r1 skin grafts. PVG-RT1r1 heart grafts were rejected acutely in recipients reconstituted with 10 X 10(6) unfractionated immune spleen cells or inocula (5 X 10(6) cells) depleted of SIg+ cells, but additional depletion of cytotoxic T cells and their precursors resulted in marked prolongation of graft survival. Reducing the reconstituting inocula from 4 X 10(6) to 2.5 X 10(6) spleen cells prolonged graft survival to that observed in unreconstituted recipients. Additional studies were performed to define the immunologic basis for prolonged survival of PVG-RT1r1 heart grafts in homozygous PVG recipients. Although lymphoid cells of naive PVG failed to proliferate on coculture with irradiated PVG-RT1r1, bulk cultures yielding but weak and variable CTL generation, lymphoid cells from specifically sensitized PVG proliferated and generated greater cytotoxic T lymphocyte (CTL) activity under identical conditions, strongly suggesting, therefore, that prolonged heart graft survival in this strain combination is related to low CTL precursor frequency.

  1. Radiation-grafted membranes based on polyethylene for direct methanol fuel cells

    NASA Astrophysics Data System (ADS)

    Sherazi, Tauqir A.; Guiver, Michael D.; Kingston, David; Ahmad, Shujaat; Kashmiri, M. Akram; Xue, Xinzhong

    Styrene was grafted onto ultrahigh molecular weight polyethylene powder (UHMWPE) by gamma irradiation using a 60Co source. Compression moulded films of selected pre-irradiated styrene-grafted ultrahigh molecular weight polyethylene (UHMWPE-g-PS) were post-sulfonated to the sulfonic acid derivative (UHMWPE-g-PSSA) for use as proton exchange membranes (PEMs). The sulfonation was confirmed by X-ray photoelectron spectroscopy (XPS). The melting and flow properties of UHMWPE and UHMWPE-g-PS are conducive to forming homogeneous pore-free membranes. Both the ion conductivity and methanol permeability coefficient increased with degree of grafting, but the grafted membranes showed comparable or higher ion conductivity and lower methanol permeability than Nafion ® 117 membrane. One UHMWPE-g-PS membrane was fabricated into a membrane-electrode assembly (MEA) and tested as a single cell direct methanol fuel cell (DMFC). Low membrane cost and acceptable fuel cell performance indicate that UHMWPE-g-PSSA membranes could offer an alternative approach to perfluorosulfonic acid-type membranes for DMFC.

  2. Modification of flax fibres by radiation induced emulsion graft copolymerization of glycidyl methacrylate

    NASA Astrophysics Data System (ADS)

    Moawia, Rihab Musaad; Nasef, Mohamed Mahmoud; Mohamed, Nor Hasimah; Ripin, Adnan

    2016-05-01

    Flax fibres were modified by radiation induced graft copolymerization of glycidyl methacrylate (GMA) by pre-irradiation method in an emulsion medium. The effect of reaction parameters on the degree of grafting (DOG) such as concentration of bleaching agent, absorbed dose, monomer concentration, temperature and reaction time were investigated. The DOG was found to be dependent on the investigated parameters. The incorporation of poly(GMA) grafts in the bleached flax fibres was confirmed by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The structural and mechanical changes were evaluated by X-ray diffraction (XRD) and mechanical tester, respectively. The results revealed that reacting bleached flax fibres irradiated with 20 kGy with 5% GMA emulsion containing 0.5% polyoxyethylene-sorbitan monolaurate (Tween 20) surfactant at 40 °C for 1 h led to a maximum DOG of 148%. The grafted fibres showed sufficient mechanical strength and hydrophobicity which make them promising precursors for development of adsorbents after appropriate chemical treatments.

  3. Grafting of water turbines runner

    SciTech Connect

    Yang, I.T.

    1983-12-01

    It is possible to graft upon or hybridize two different types of water turbines' runner in order to attain more perfect performance to meeting engineering needs. The answer is positive and very interesting, as shown in the research experiment in the Hydromachines Laboratory of Gansu University of Technology. Grafting a group of propeller blades (Ns=440 N.KW) on a Francis turbine runner (Ns=200) with certain boundary conditions in the flow areas, a new hybrid multiplex runner performance has been achieved. Its efficiency curve has been improved at high speed and large flow rate operating conditions that could be able to meet the engineering requirements when the head of the hydropower station is lower than normal. Its unit rotation speed is increased about 25% over that of the Francis. The general performance curve of this hybrid runner will be provided in this paper.

  4. Surface characterization of binary grafting of AAc/NIPAAm onto poly(tetrafluoroethylene) (PTFE)

    NASA Astrophysics Data System (ADS)

    Adem, E.; Avalos-Borja, M.; Bucio, E.; Burillo, G.; Castillon, F. F.; Cota, L.

    2005-07-01

    The present study shows results on radiation grafting of acrylic acid (AAc) and N-isopropylacrylamide (NIPAAm) mixtures onto polytetrafluoroethylene (PTFE) films. The main objective is to use the modified polymer for immobilization of the avidin-streptavidin systems or other bio-compounds. Grafting onto PTFE was carried out by the pre-irradiation oxidative method in air at different dose rates and irradiation doses. The irradiation was produced with the electron beam of a 2 MV van de Graaff accelerator, and gamma-rays, from a Gamma Beam 651 PT. The samples were placed in glass ampoules with the AAc and NIPAAm mixtures, in an aqueous solution. Graft polymerization was performed by heating of the polymer-monomer composition in an argon atmosphere at temperature of 50 °C. Surface funcionalization was studied by X-ray photoelectron spectroscopy (XPS); morphology of the surface was studied by scanning electron microscopy (SEM) and hydrophylization of the surface, by contact angle measurements (static method).

  5. [Bone grafts using tissue engineering].

    PubMed

    Delloye, C

    2001-01-01

    An overview of bone grafts and, in particular, the allografts is presented. The availability of bone allografts, has promoted their use at the expense of the autograft. However, the loss of the cellular activity in an allograft, makes them less performant than an autograft. The use of an allograft in a small size defect can be advocated provided that the implantation technique is stringent. In case of a large segmental bone defect, an allograft can be considered whereas an autograft is not anymore possible. A massive bone allograft allows an anatomical reconstruction and the preservation of strong tendon insertions. In tumor surgery, a bone allograft has become one of the best options to reshape the skeleton. To offset the poor remodeling of the massive bone allografts, and to improve the take of small size bone allografts, researches are presently carried on, using tissue engineering in order to recover a cellular population. The aim is to combine an acellular bone graft with the cells of the recipient. Cells are procured from the bone marrow. Stromal cells are isolated, cultured, so that they will grow with an osteoblastic phenotype. They can be used alone or in association with a bone graft. It is believed that tomorrow such cellular therapy will become a routine procedure.

  6. Assessment of the use of LED phototherapy on bone defects grafted with hydroxyapatite on rats with iron-deficiency anemia and nonanemic: a Raman spectroscopy analysis.

    PubMed

    de Castro, Isabele Cardoso Vieira; Rosa, Cristiane Becher; Dos Reis Júnior, João Alves; Moreira, Luiz Gaudêncio Passos; Aragão, Juliana S; Barbosa, Artur Felipe dos Santos; Silveira, Landulfo; Pinheiro, Antonio L B

    2014-09-01

    This study aimed to assess bone repair in defects grafted or not with hydroxyapatite (HA) on healthy and iron-deficiency anemia (IDA) rats submitted or not to LED phototherapy (LED-PT) by Raman spectroscopy. The animals were divided in eight groups with five rats each: Clot; Clot + LED; IDA + Clot; IDA + LED; Graft; Graft + LED; IDA + Graft; and IDA + Graft + LED. When appropriated, irradiation with IR LED (λ850 ± 10 nm, 150 mW, CW, Φ = 0.5 cm(2), 16 J/cm(2), 15 days) was carried out. Raman shifts: ∼ 960 [symmetric PO4 stretching (phosphate apatite)], ∼ 1,070 [symmetric CO3 stretching (B-type carbonate apatite)], and ∼ 1,454 cm(-1) [CH2/CH3 bending in organics (protein)] were analyzed. The mean peak values for ∼ 960, ∼ 1,070, and ∼ 1,454 cm(-1) were nonsignificantly different on healthy or anemic rats. The group IDA + Graft + LED showed the lowest mean values for the peak ∼ 960 cm(-1) when compared with the irradiated IDA group or not (p ≤ 0.001; p ≤ 0.001). The association of LED-PT and HA-graft showed lowest mean peak at ∼ 1,454 cm(-1) for the IDA rats. The results of this study indicated higher HA peaks as well as a decrease in the level of organic components on healthy animals when graft and LED phototherapy are associated. In the other hand, IDA condition interfered in the graft incorporation to the bone as LED phototherapy only improved bone repair when graft was not used.

  7. Canine pancreas and kidney transplantation following total-lymphoid irradiation

    SciTech Connect

    Williamson, P.; Allen, R.D.; Deane, S.A.; Ekberg, H.; Grierson, J.M.; Hawthorne, W.J.; Mears, D.C.; Tiver, K.; Little, J.M.; Stewart, G.J. )

    1990-10-01

    The effect of total-lymphoid irradiation on survival of canine pancreas and kidney allografts was studied. TLI had a marked immunosuppressive effect as measured by in vitro immune responses and reduced circulating leukocytes. Despite the changes, median graft survival times for animals treated with 800 cGy (9 days) or 1800 cGy (9.5 days) were not significantly different from untreated control animals (7 days). The addition of low-dose antithymocyte globulin (10 mg/kg/day) on post-transplant days 0, 2, 4, 6, 8, and 10 had no measurable synergistic effect. Similarly, median segmental pancreas allograft survival times after 1700-2200 cGy of TLI treatment (16.5 days) were only marginally longer than those of untreated controls (9 days). The only animal to maintain a graft for greater than 200 days was matched to the donor in mixed lymphocyte culture (MLC). This animal was able to reject a third-party skin graft after 8 days while a graft from the original donor was still surviving after 21 days when the pancreas graft failed from a chronic-type rejection. These results indicate that TLI alone or in combination with ATG will not be predictably effective as a method of prolonging allograft survival. The role of matching major histocompatibility complex antigens in TLI treatment requires clarification.

  8. Conservative Pancreas Graft Preservation at the Extreme

    PubMed Central

    Laurence, Jerome Martin; Sapisochin, Gonzalo; Selzner, Markus; Norgate, Andrea; Kumar, Deepali; McGilvary, Ian D.; Preig, Paul D.; Schiff, Jeffrey; Cattral, Mark S.

    2016-01-01

    Because of the value some patients place in remaining insulin-independent after pancreas transplantation, they may be reluctant to undergo graft pancreatectomy, even in the face of extreme complications, such as graft thrombosis and duodenal segment leak. Partly, for this reason, a variety of complex salvage techniques have been described to save the graft in such circumstances. We report a case of a series of extreme complications related to a leak from the duodenal segment after a simultaneous pancreas and kidney transplant. These included infected thrombosis of the inferior vena cava associated with a graft venous thrombosis and a retroperitoneal fistula. The patient retained graft function with insulin independence and repeatedly declined graft pancreatectomy against the advice of the transplant team. Conservative treatment with percutaneous drainage, antibiotics, and anticoagulation was eventually successful. This outcome is unique in our experience and may be instructive to teams caring for pancreas transplant recipients. PMID:27500244

  9. Planarian immobilization, partial irradiation, and tissue transplantation.

    PubMed

    Guedelhoefer, Otto C; Sánchez Alvarado, Alejandro

    2012-08-06

    The planarian, a freshwater flatworm, has proven to be a powerful system for dissecting metazoan regeneration and stem cell biology. Planarian regeneration of any missing or damaged tissues is made possible by adult stem cells termed neoblasts. Although these stem cells have been definitively shown to be pluripotent and singularly capable of reconstituting an entire animal, the heterogeneity within the stem cell population and the dynamics of their cellular behaviors remain largely unresolved. Due to the large number and wide distribution of stem cells throughout the planarian body plan, advanced methods for manipulating subpopulations of stem cells for molecular and functional study in vivo are needed. Tissue transplantation and partial irradiation are two methods by which a subpopulation of planarian stem cells can be isolated for further study. Each technique has distinct advantages. Tissue transplantation allows for the introduction of stem cells, into a naïve host, that are either inherently genetically distinct or have been previously treated pharmacologically. Alternatively, partial irradiation allows for the isolation of stem cells within a host, juxtaposed to tissue devoid of stem cells, without the introduction of a wound or any breech in tissue integrity. Using these two methods, one can investigate the cell autonomous and non-autonomous factors that control stem cell functions, such as proliferation, differentiation, and migration. Both tissue transplantation and partial irradiation have been used historically in defining many of the questions about planarian regeneration that remain under study today. However, these techniques have remained underused due to the laborious and inconsistent nature of previous methods. The protocols presented here represent a large step forward in decreasing the time and effort necessary to reproducibly generate large numbers of grafted or partially irradiated animals with efficacies approaching 100 percent. We cover the

  10. Planarian Immobilization, Partial Irradiation, and Tissue Transplantation

    PubMed Central

    Guedelhoefer IV, Otto C.; Sánchez Alvarado, Alejandro

    2012-01-01

    The planarian, a freshwater flatworm, has proven to be a powerful system for dissecting metazoan regeneration and stem cell biology1,2. Planarian regeneration of any missing or damaged tissues is made possible by adult stem cells termed neoblasts3. Although these stem cells have been definitively shown to be pluripotent and singularly capable of reconstituting an entire animal4, the heterogeneity within the stem cell population and the dynamics of their cellular behaviors remain largely unresolved. Due to the large number and wide distribution of stem cells throughout the planarian body plan, advanced methods for manipulating subpopulations of stem cells for molecular and functional study in vivo are needed. Tissue transplantation and partial irradiation are two methods by which a subpopulation of planarian stem cells can be isolated for further study. Each technique has distinct advantages. Tissue transplantation allows for the introduction of stem cells, into a naïve host, that are either inherently genetically distinct or have been previously treated pharmacologically. Alternatively, partial irradiation allows for the isolation of stem cells within a host, juxtaposed to tissue devoid of stem cells, without the introduction of a wound or any breech in tissue integrity. Using these two methods, one can investigate the cell autonomous and non-autonomous factors that control stem cell functions, such as proliferation, differentiation, and migration. Both tissue transplantation5,6 and partial irradiation7 have been used historically in defining many of the questions about planarian regeneration that remain under study today. However, these techniques have remained underused due to the laborious and inconsistent nature of previous methods. The protocols presented here represent a large step forward in decreasing the time and effort necessary to reproducibly generate large numbers of grafted or partially irradiated animals with efficacies approaching 100 percent. We

  11. Commercial food irradiation

    SciTech Connect

    Black, E.F.; Libby, L.M.

    1983-06-01

    Food irradiation is discussed. Irradiation exposes food to gamma rays from a cobalt-60 or a cesium-137 source, or to high-energy electrons emitted by an electron accelerator. A major advantage is that food can be packaged either before or after treatment. FDA regulations with regard to irradiation are discussed. Comments on an 'Advance Notice' on irradiation, published by the FDA in 1981 are summarized.

  12. Novel expansion techniques for skin grafts

    PubMed Central

    Kadam, Dinesh

    2016-01-01

    The quest for skin expansion is not restricted to cover a large area alone, but to produce acceptable uniform surfaces, robust engraftment to withstand mechanical shear and infection, with a minimal donor morbidity. Ease of the technique, shorter healing period and reproducible results are essential parameters to adopt novel techniques. Significant advances seen in four fronts of autologous grafting are: (1) Dermal–epidermal graft expansion techniques, (2) epidermal graft harvests technique, (3) melanocyte-rich basal cell therapy for vitiligo and (4) robust and faster autologous cell cultures. Meek's original concept that the sum of perimeter of smaller grafts is larger than the harvested graft, and smaller the graft size, the greater is the potential for regeneration is witnessed in newer modification. Further, as graft size becomes smaller or minced, these micrografts can survive on the wound bed exudate irrespective of their dermal orientation. Expansion produced by 4 mm × 4 mm sized Meek micrografts is 10-folds, similarly 0.8 mm × 0.8 mm size micrografts produce 100-fold expansion, which becomes 700-fold with pixel grafts of 0.3 mm × 0.3 mm size. Fractional skin harvest is another new technique with 700 μ size full thickness graft. These provide instant autologous non-cultured graft to cover extensive areas with similar quality of engraftment surface as split skin grafts. Newer tools for epidermal blister graft harvest quickly, with uniform size to produce 7-fold expansions with reproducible results. In addition, donor area heals faster with minimal scar. Melanocyte-rich cell suspension is utilised in vitiligo surgery tapping the potential of hair root melanocytes. Further advances in the cell culture to reduce the cultivation time and provide stronger epidermal sheets with dermal carrier are seen in trials. PMID:27274117

  13. Preoperative graft assessment in aortocoronary bypass surgery

    PubMed Central

    Tinica, Grigore; Vartic, Cristina Luca; Mocanu, Veronica; Baran, Dana; Butcovan, Doina

    2016-01-01

    Coronary artery bypass graft (CABG) is a surgical procedure able to improve the blood supply to the myocardium. In the present study, the distal segments of grafts taken from the internal thoracic artery (ITA), radial artery (RA) and saphenous vein (SV) for use in aortocoronary bypass surgery were examined. The morphologies of the grafts were investigated in order to draw conclusions concerning their patency and viability. In addition, clinical and laboratory risk factors considered to be significant predictors of lesion severity in graft vessels used in CABGs were investigated. In total, 54 distal graft segments of ITAs, RAs and SVs from 20 men and 6 women aged between 42 and 78 years, were evaluated. Histological analyses were used to visualize graft lesions. Morphometrically, the intimal thickness index (ITI) and luminal narrowing were assessed as an indication of graft patency. The histological changes observed in the graft vessel walls included the presence of distinct atheromatous plaques (fatty streaks in 2 cases) or thickening of the intima (20 cases) and media (17 cases). Morphometric analysis showed that the mean ITI of the vessel conduits was 0.37 in the SVs, 0.95 in the RAs, and 1.66 in the ITAs. No patient had >50% conduit stenosis. By assessing the association between risk factors and graft lesions, it was found that all the patients showed risk factors for atherosclerosis, such as age (61.54%), arterial hypertension (65.38%), hyperlipidemia (65.38%), smoking (34.61%), diabetes mellitus (38.46%) and obesity (15.38%). The presence of pre-existing lesions in bypass grafts may contribute to a reduction in their viability, particularly in the case of venous grafts. Further long-term follow-ups are mandatory to evaluate the consequences of such lesions upon the patency of the grafts. PMID:27446279

  14. Organosiloxane-grafted natural polymer coatings

    DOEpatents

    Sugama, Toshifumi

    1998-12-01

    A new family of polysaccharide graft polymers are provided as corrosion resistant coatings having antimicrobial properties which are useful on light metals such as aluminum, magnesium, zinc, steel and their alloys. Methods of making the polysaccharide graft polymers are also included. The methods of making the polysaccharide graft polymers involve reacting a polysaccharide source with an antimicrobial agent under conditions of hydrolysis-condensation. 17 figs.

  15. Induction of tolerance to cardiac allografts in lethally irradiated rats reconstituted with syngeneic bone marrow

    SciTech Connect

    Hartnett, L.C.

    1983-01-01

    Generally, organ grafts from one individual animal to another are rejected in one-two weeks. However, if the recipients are given Total Body Irradiation (TBI) just prior to grafting, followed by reconstitution of hemopoietic function with syngeneic (recipient-type) bone marrow cells, then vascularized organ grafts are permanently accepted. Initially after irradiation, it is possible to induce tolerance to many strain combinations in rats. This thesis examines the system of TBI as applied to the induction of tolerance in LEW recipients of WF cardiac allografts. These two rat strains are mismatched across the entire major histocompatibility complex. When the LEW recipient are given 860 rads, a WF cardiac allograft and LEW bone marrow on the same day, 60% of the grafts are accepted. Methods employed to improve the rate of graft acceptance include: treating either donor or recipient with small amounts of methotrexate, or waiting until two days after irradiation to repopulate with bone marrow. It seems from these investigations of some of the early events in the induction of tolerance to allografts following TBI and syngeneic marrow reconstitution that an immature cell population in the bone marrow interacts with a radioresistant cell population in the spleen to produce tolerance to completely MHC-mismatched allografts.

  16. Interdigitating reticulum cells in human renal grafts.

    PubMed

    Wakabayashi, T; Onoda, H

    1991-01-01

    Seventeen human renal graft biopsies taken 1 h to 50 days after transplantation and 3 human renal non-graft biopsies (2 minimal change and 1 non-tumour portion of angiomyolipoma) were investigated with immunoelectron microscopy in order to identify interdigitating reticulum cells (IDC) or dendritic cells (DC) in renal tissues. The antibodies used consisted of a rabbit polyclonal antibody of antihuman S100 beta protein, mouse monoclonal antibodies of antihuman HLA-DR, anti-CD3, and anti-CD1a. IDC or DC were identified in 11 renal grafts. They were found both in the glomerular and interstitial (peritubular) capillary lumens but not in the interstitium of 1 case: both were present in the interstitial capillary lumens and interstitium of another case, and in the interstitium only of 9 cases. In the remaining 6 grafts and 3 non-grafts they were not detected. These 6 grafts and 3 non-grafts did not show any pathological change except for foot process fusion of the glomerular epithelia in 2 cases of minimal change. These findings suggest that IDC or DC are not normally present in human renal tissues. The presence of the cell in the glomerular and peritubular capillary lumens of a biopsy taken after 1 h and their presence in the interstitial capillary lumens of another graft biopsy, suggest that the IDC or DC in human renal grafts are derived from recipients, not donors, and that they migrate from the circulating blood toward the interstitium.

  17. Plant grafting: insights into tissue regeneration

    PubMed Central

    2016-01-01

    Abstract For millennia, people have cut and joined different plants together through a process known as grafting. The severed tissues adhere, the cells divide and the vasculature differentiates through a remarkable process of regeneration between two genetically distinct organisms as they become one. Grafting is becoming increasingly important in horticulture where it provides an efficient means for asexual propagation. Grafting also combines desirable roots and shoots to generate chimeras that are more vigorous, more pathogen resistant and more abiotic stress resistant. Thus, it presents an elegant and efficient way to improve plant productivity in vegetables and trees using traditional techniques. Despite this horticultural importance, we are only beginning to understand how plants regenerate tissues at the graft junction. By understanding grafting better, we can shed light on fundamental regeneration pathways and the basis for self/non‐self recognition. We can also better understand why many plants efficiently graft whereas others cannot, with the goal of improving grafting so as to broaden the range of grafted plants to create even more desirable chimeras. Here, I review the latest findings describing how plants graft and provide insight into future directions in this emerging field. PMID:28316790

  18. Late infection in Dacron arterial grafts.

    PubMed

    Harvey, D R; Bliss, B P

    1975-06-01

    We report a series of cases of late infection in Dacron arterial grafts. Late infection is defined as that presenting de novo 6 months or more after the patient's discharge from hospital with a clean healed wound. One hundred and ten patients were followed up and 6 cases of this type of infection occurred. The diagnosis was made on clinical grounds and usually pain, suppuration in the line of graft, or graft exposure were the presenting features. Secondary haemorrhage, common in early infection, did not occur. Conservative management failed in most cases and removal of the infected graft was necessary. The difficult problems associated with revascularization are discussed.

  19. Does Total Body Irradiation Conditioning Improve Outcomes of Myeloablative HLA-Identical Sibling Transplants for Chronic Lymphocytic Leukemia?

    PubMed Central

    Sabloff, Mitchell; Sobecks, Ronald M.; Ahn, Kwang Woo; Zhu, Xiaochun; de Lima, Marcos; Brown, Jennifer R.; Inamoto, Yoshihiro; Holland, H. Kent; Aljurf, Mahmoud D.; Laughlin, Mary J.; Kamble, Rammurti T.; Hsu, Jack W.; Wirk, Baldeep M.; Seftel, Matthew; Lewis, Ian D.; Arora, Mukta; Alyea, Edwin P.; Kalaycio, Matt E.; Cortes, Jorge; Maziarz, Richard T.; Gale, Robert Peter; Saber, Wael

    2014-01-01

    An allogeneic hematopoietic cell transplant (HCT) from an HLA-identical donor after high-dose (myeloablative) pre-transplant conditioning, is an effective therapy for some people with chronic lymphocytic leukemia (CLL). Because CLL is a highly radiosensitive cancer, we hypothesized total body irradiation (TBI) conditioning regimens may be associated with better outcomes than those without TBI. To answer this we analyzed data from 180 subjects with CLL receiving myeloablative doses of TBI (N=126) or not (N=54), transplanted from an HLA-identical sibling donor, between 1995 and 2007 and reported to the Center for International Blood & Marrow Transplant Research (CIBMTR). At 5 years, treatment-related mortality was 48% (95% CI, 39–57%) vs. 50% (95% CI, 36–64%); p=NS. Relapse rates were 17% (95% CI, 11–25%) vs. 22% (95% CI, 11–35%); p=NS. Five-year progression-free survival and overall survival was 34% (95% CI, 26–43%) vs. 28% (95% CI, 15–42%); p=NS and 42% (95% CI, 33–51%) vs. 33% (95% CI, 19–48%); p=NS, respectively. The single most common cause of death in both cohorts was recurrent/progressive CLL. No variable tested in the multivariate analysis was found to significantly affect these outcomes including having failed fludarabine. Within the limitations of this study we found no difference in HLA-identical sibling transplant outcomes between myeloablative TBI and chemotherapy pre-transplant conditioning in persons with CLL. PMID:24321745

  20. Welding irradiated stainless steel

    SciTech Connect

    Kanne, W.R. Jr.; Chandler, G.T.; Nelson, D.Z.; Franco-Ferreira, E.A.

    1993-12-31

    Conventional welding processes produced severe underbead cracking in irradiated stainless steel containing 1 to 33 appm helium from n,a reactions. A shallow penetration overlay technique was successfully demonstrated for welding irradiated stainless steel. The technique was applied to irradiated 304 stainless steel that contained 10 appm helium. Surface cracking, present in conventional welds made on the same steel at the same and lower helium concentrations, was eliminated. Underbead cracking was minimal compared to conventional welding methods. However, cracking in the irradiated material was greater than in tritium charged and aged material at the same helium concentrations. The overlay technique provides a potential method for repair or modification of irradiated reactor materials.

  1. The effects of different schedules of total-body irradiation in heterotopic vascularized bone transplantation. An experimental study in the Lewis rat

    SciTech Connect

    Gonzalez del Pino, J.; Benito, M.; Randolph, M.A.; Weiland, A.J. )

    1990-12-01

    To evaluate the effects of irradiation on heterotopically placed vascularized knee isografts, a single dose of 10 Gy of total-body irradiation was given to Lewis donor rats. Irradiation was delivered either 2 or 6 days prior to harvesting or subsequent transplantation, and evaluated at 1, 2, and 4 weeks after grafting. Irradiation caused endothelial depopulation of the graft artery, although vascular pedicle patency was maintained throughout the study. Bone graft viability and mineralization were normal. Dramatic changes in the bone marrow were seen that included an increase of its fat content (P less than 0.001), and a concomitant decrease in bone marrow-derived immunocompetent cells. These changes were more prominent in recipients of grafts from day -6 irradiated donor rats. Total-body irradiation did not prejudice the use of vascularized bone grafts, and exhibited an associated immunosuppresant effect over the vascular endothelium and bone marrow. This may be a further rational conditioning procedure to avoid recipient manipulation in vascularized bone allotransplantation.

  2. Total lymphoid irradiation in heart transplantation: Adjunctive treatment for recurrent rejection

    SciTech Connect

    Frist, W.H.; Winterland, A.W.; Gerhardt, E.B.; Merrill, W.H.; Atkinson, J.B.; Eastburn, T.E.; Stewart, J.R.; Eisert, D.R. )

    1989-12-01

    In the face of recurrent heart transplant graft rejection refractory to all conventional immunotherapy, retransplantation is customary treatment. The case of a heart transplant recipient unsuitable for retransplantation whose recurrent rejection was successfully treated with postoperative total lymphoid irradiation is described.

  3. What to Expect during Coronary Artery Bypass Grafting

    MedlinePlus

    ... NHLBI on Twitter. What To Expect During Coronary Artery Bypass Grafting Coronary artery bypass grafting (CABG) requires ... surgery to newer, less-invasive methods. Traditional Coronary Artery Bypass Grafting This type of surgery usually lasts ...

  4. Initiator Effects in Reactive Extrusion of Starch Graft Copolymers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Graft copolymers of starch with water-soluble polymers such as polyacrylamide have potential applications including hydrogels, superabsorbents, and thickening agents. Reactive extrusion is a rapid, continuous method for production of starch graft copolymers with high reaction and grafting efficienc...

  5. High-dose electron beam sterilization of soft-tissue grafts maintains significantly improved biomechanical properties compared to standard gamma treatment.

    PubMed

    Hoburg, A; Keshlaf, S; Schmidt, T; Smith, M; Gohs, U; Perka, C; Pruss, A; Scheffler, S

    2015-06-01

    Allografts have gained increasing popularity in anterior cruciate ligament (ACL) reconstruction. However, one of the major concerns regarding allografts is the possibility of disease transmission. Electron beam (Ebeam) and Gamma radiation have been proven to be successful in sterilization of medical products. In soft tissue sterilization high dosages of gamma irradiation have been shown to be detrimental to biomechanical properties of grafts. Therefore, it was the objective of this study to compare the biomechanical properties of human bone-patellar tendon-bone (BPTB) grafts after ebeam with standard gamma irradiation at medium (25 kGy) and high doses (34 kGy). We hypothesized that the biomechanical properties of Ebeam irradiated grafts would be superior to gamma irradiated grafts. Paired 10 mm-wide human BPTB grafts were harvested from 20 donors split into four groups following irradiation with either gamma or Ebeam (each n = 10): (A) Ebeam 25 kGy, (B) Gamma 25 kGy, (C) Ebeam 34 kGy (D) Gamma 34 kGy and ten non-irradiated BPTB grafts were used as controls. All grafts underwent biomechanical testing which included preconditioning (ten cycles, 0-20 N); cyclic loading (200 cycles, 20-200 N) and a load-to-failure (LTF) test. Stiffness of non-irradiated controls (199.6 ± 59.1 N/mm) and Ebeam sterilized grafts did not significantly differ (152.0 ± 37.0 N/mm; 192.8 ± 58.0 N/mm), while Gamma-irradiated grafts had significantly lower stiffness than controls at both irradiation dosages (25 kGy: 126.1 ± 45.4 N/mm; 34 kGy: 170.6 ± 58.2 N/mm) (p < 0.05). Failure loads at 25 kGy were significantly lower in the gamma group (1,009 ± 400 N), while the failure load was significantly lower in both study groups at high dose irradiation with 34 kGy (Ebeam: 1,139 ± 445 N, Gamma: 1,073 ± 617 N) compared to controls (1,741 ± 304 N) (p < 0.05). Creep was significantly larger in the gamma irradiated groups (25 kGy: 0.96 ± 1.34 mm; 34 kGy: 1.06 ± 0.58 mm) than in the Ebeam (25 k

  6. Mouse models for graft arteriosclerosis.

    PubMed

    Qin, Lingfeng; Yu, Luyang; Min, Wang

    2013-05-14

    Graft arteriosclerois (GA), also called allograft vasculopathy, is a pathologic lesion that develops over months to years in transplanted organs characterized by diffuse, circumferential stenosis of the entire graft vascular tree. The most critical component of GA pathogenesis is the proliferation of smooth muscle-like cells within the intima. When a human coronary artery segment is interposed into the infra-renal aortae of immunodeficient mice, the intimas could be expand in response to adoptively transferred human T cells allogeneic to the artery donor or exogenous human IFN-γ in the absence of human T cells. Interposition of a mouse aorta from one strain into another mouse strain recipient is limited as a model for chronic rejection in humans because the acute cell-mediated rejection response in this mouse model completely eliminates all donor-derived vascular cells from the graft within two-three weeks. We have recently developed two new mouse models to circumvent these problems. The first model involves interposition of a vessel segment from a male mouse into a female recipient of the same inbred strain (C57BL/6J). Graft rejection in this case is directed only against minor histocompatibility antigens encoded by the Y chromosome (present in the male but not the female) and the rejection response that ensues is sufficiently indolent to preserve donor-derived smooth muscle cells for several weeks. The second model involves interposing an artery segment from a wild type C57BL/6J mouse donor into a host mouse of the same strain and gender that lacks the receptor for IFN-γ followed by administration of mouse IFN-γ (delivered via infection of the mouse liver with an adenoviral vector. There is no rejection in this case as both donor and recipient mice are of the same strain and gender but donor smooth muscle cells proliferate in response to the cytokine while host-derived cells, lacking receptor for this cytokine, are unresponsive. By backcrossing additional

  7. Fat grafting in facial rejuvenation.

    PubMed

    Marten, Timothy J; Elyassnia, Dino

    2015-04-01

    Patients with significant facial atrophy and age-related loss of facial fat generally achieve suboptimal improvement from both surface treatments of facial skin and surgical lifts. Restoring lost facial volume by fat grafting is a powerful technique that is now acknowledged by most plastic surgeons and other physicians engaged in treating the aging face as one of the most important advances in aesthetic surgery. Properly performed, the addition of fat to areas of the face that have atrophied because of age or disease can produce a significant and sustained improvement in appearance that is unobtainable by other means.

  8. Grafted methylenediphosphonate ion exchange resins

    DOEpatents

    Trochimcznk, A.W.; Gatrone, R.C.; Alexandratos, S.; Horwitz, E.P.

    1997-04-08

    An ion exchange resin is disclosed that is comprised of an insoluble copolymer onto which are grafted pendent groups that provide 1.0 to about 10 mmol/g dry weight phosphorus. The pendent groups have the formula as shown in the patent wherein R is hydrogen, a cation or mixtures thereof; and R{sup 1} is hydrogen or an C{sub 1}-C{sub 2} alkyl group. The resin also contains zero to about 5 mmol/g dry weight of pendent aromatic sulfonate groups. Processes for making and using an ion exchange resin are also disclosed.

  9. Grafted methylenediphosphonate ion exchange resins

    DOEpatents

    Trochimcznk, Andrzej W.; Gatrone, Ralph C.; Alexandratos, Spiro; Horwitz, E. Philip

    1998-01-27

    An ion exchange resin is disclosed that is comprised of an insoluble copolymer onto which are grafted pendent groups that provide 1.0 to about 10 mmol/g dry weight phosphorous. The pendent groups have the formula ##STR1## wherein R is hydrogen, a cation or mixtures thereof; and R.sup.1 is hydrogen or an C.sub.1 -C.sub.2 alkyl group. The resin also contains zero to about 5 mmol/g dry weight of pendent aromatic sulfonate groups. Processes for making and using an ion exchange-resin are also disclosed.

  10. Grafted methylenediphosphonate ion exchange resins

    DOEpatents

    Trochimcznk, Andrzej W.; Gatrone, Ralph C.; Alexandratos, Spiro; Horwitz, E. Philip

    1997-01-01

    An ion exchange resin is disclosed that is comprised of an insoluble copolymer onto which are grafted pendent groups that provide 1.0 to about 10 mmol/g dry weight phosphorous. The pendent groups have the formula ##STR1## wherein R is hydrogen, a cation or mixtures thereof; and R.sup.1 is hydrogen or an C.sub.1 -C.sub.2 alkyl group. The resin also contains zero to about 5 mmol/g dry weight of pendent aromatic sulfonate groups. Processes for making and using an ion exchange resin are also disclosed.

  11. Design and development of multilayer vascular graft

    NASA Astrophysics Data System (ADS)

    Madhavan, Krishna

    2011-07-01

    Vascular graft is a widely-used medical device for the treatment of vascular diseases such as atherosclerosis and aneurysm as well as for the use of vascular access and pediatric shunt, which are major causes of mortality and morbidity in this world. Dysfunction of vascular grafts often occurs, particularly for grafts with diameter less than 6mm, and is associated with the design of graft materials. Mechanical strength, compliance, permeability, endothelialization and availability are issues of most concern for vascular graft materials. To address these issues, we have designed a biodegradable, compliant graft made of hybrid multilayer by combining an intimal equivalent, electrospun heparin-impregnated poly-epsilon-caprolactone nanofibers, with a medial equivalent, a crosslinked collagen-chitosan-based gel scaffold. The intimal equivalent is designed to build mechanical strength and stability suitable for in vivo grafting and to prevent thrombosis. The medial equivalent is designed to serve as a scaffold for the activity of the smooth muscle cells important for vascular healing and regeneration. Our results have shown that genipin is a biocompatible crosslinker to enhance the mechanical properties of collagen-chitosan based scaffolds, and the degradation time and the activity of smooth muscle cells in the scaffold can be modulated by the crosslinking degree. For vascular grafting and regeneration in vivo, an important design parameter of the hybrid multilayer is the interface adhesion between the intimal and medial equivalents. With diametrically opposite affinities to water, delamination of the two layers occurs. Physical or chemical modification techniques were thus used to enhance the adhesion. Microscopic examination and graft-relevant functional characterizations have been performed to evaluate these techniques. Results from characterization of microstructure and functional properties, including burst strength, compliance, water permeability and suture

  12. Clinical and anti-HLA antibody profile of nine renal transplant recipients with failed grafts: donor-specific and non-donor-specific antibody development.

    PubMed

    Rebellato, Lorita M; Ozawa, Miyuki; Verbanac, Kathryn M; Catrou, Paul; Haisch, Carl E; Terasaki, Paul I

    2006-01-01

    This study applied the single antigen microsphere technology to the retrospective analysis of sequential post-transplant serum samples in the context of the patient's clinical course. Detailed information on nine of the study patients was presented as representative of the larger cohort and illustrative of different patterns of anti-HLA antibody development and different clinical scenarios that culminated in graft failure. Our major observations are summarized as follows: 1. These data confirm the high sensitivity of the single antigen bead method: In some patients, DSA and NDSA that were undetected by standard methods were found pre-transplant and in sequential post-transplant samples. 2. The precise role that anti-HLA antibody plays in a particular rejection are complicated in cases in which humoral rejection is not diagnosed in the biopsy: The possible involvement of ADCC and mechanisms involving an indirect role for antibody in the rejection process should be carefully investigated. 3. Although anti-HLA antibodies are associated with graft rejection, the time interval between detection and rejection can vary dramatically between patients. Both DSA and NDSA can be adsorbed by the graft and erratically detected in the circulation, in some cases remaining undetected until nephrectomy. 4. Anti-HLA antibody strengths often fluctuate widely over a patient's clinical course, with de novo DSA generally of greater strength than de novo NDSA. 5. In addition to DSA, we have observed the consistent induction of diverse, cross-reactive NDSA. This occurs not only during the post-transplant course but also after graft failure, when immunosuppression is tapered prior to nephrectomy. Our data support further studies to evaluate the value of prospective monitoring of anti-HLA antibodies to better understand the place of anti-HLA antibodies in acute rejection. This may improve our ability to reverse some acute rejection episodes. Since acute rejection has been considered a

  13. Differential immune response of congenic mice to ultraviolet-treated major histocompatibility complex class II-incompatible skin grafts

    SciTech Connect

    Vermeer, B.J.; Santerse, B.; Van De Kerckhove, B.A.; Schothorst, A.A.; Claas, F.H.

    1988-03-01

    The influence of ultraviolet (UVB) irradiation on the survival of H-2 class II-disparate skin grafts was studied in congenic mouse strains. Isolated skin was UVB irradiated in vitro at a dose of 40 mJ/cm/sup 2/ from both sides to remove Ia immunogenicity. Immediately after irradiation the skin was transplanted onto the flank of allogeneic mice. When B10.AQR grafts were transplanted onto B10.T(6R) recipients, a significant prolongation of the survival time was observed, while 50% of the UVB-treated grafts were not rejected at all. However, in the opposite direction--i.e., B10.T(6R) grafts onto B10.AQR recipients, no significant prolongation of the survival was observed. To test whether this effect was due to a difference in susceptibility of the donor skin to UVB irradiation or to a different immune response in the recipients, (B10.T(6R) x B10.AQR) grafts were transplanted onto the parent strains. Similar results were obtained, in that UVB-treated grafts did not show a prolonged survival in B10.AQR recipients, whereas a significant prolongation (50% of the grafts survived more than 100 days) was observed in B10.T(6R) recipients. UVB-treated (B10.T(6R) x B10.AQR)F1 grafts were also transplanted onto (B10.T(6R) x C57B1/10)F1, (B10.AQR x C57B1/10)F1, (B10.T(6R) x Balb/c)F1 and (B10.AQR x Balb/c)F1 recipients--but in none of these combinations was a prolonged survival time observed. These data suggest that, in contrast to all in vitro experiments, the abrogation of the immune response by UVB treatment of the stimulator cells is, in vivo, not a general phenomenon. The genetic constitution of the responder mice seems to play an important role in determining whether or not an immune response takes place.

  14. Radiation grafting of various water-soluble monomers on ultra-high molecular weight polyethylene powder. Part II: Thermal, FTIR and morphological characterisation

    NASA Astrophysics Data System (ADS)

    Aydınlı, Bahattin; Tin c̡er, Teoman

    2001-10-01

    Radiation induced grafted polyacrylic acid (PAA), polymethacrylic acid (PMAA), polyacrylamide (PAAm), poly N,N-dimethyl acrylamide (PNDAAm) and poly 1-vinyl-2 pyrrolidone (PVP) on ultra-high molecular weight polyethylene (UHMWPE) were characterised by DSC, FTIR and SEM analysis. While the effect of irradiation on pure UHMWPE was found to increase crystallinity and cause higher enthalpy of crystallisation, grafted UHMWPE powders showed lower crystallinity and enthalpy of crystallisation. In all grafted UHMWPE there existed secondary transitions corresponding to grafting polymers in the first run of DSC above 60°C and they became clearer at a higher grafting level. In the second run of DSC some Tg values appeared to shift to higher temperatures while some were not detected. FTIR analysis indicated the presence of water-soluble polymers in the grafted UHMWPE. The characteristic peaks of water-soluble polymers became sharper in the grafted UHMWPE. SEM analysis revealed that the grafting occurs both on fiber and microparticles of UHMWPE while flowing characteristic of powder is retained.

  15. Recipient Wound Bed Characteristics Affect Scarring and Skin Graft Contraction

    DTIC Science & Technology

    2015-02-13

    skin grafting onto hypodermis vs. onto fascia. Compared to autografts grafted onto fascia, identical thickness autografts grafted onto fat demonstrated...reduced contraction, enhanced mobility and vascularity, and reduced topographical variability. Grafts onto fat also showed reduced levels of...skin grafts onto fat report better range of motion compared with patients who receive skin grafts directly onto fascia.3 The same study also found that

  16. Cell-Assisted Lipotransfer Improves Volume Retention in Irradiated Recipient Sites and Rescues Radiation-Induced Skin Changes

    PubMed Central

    Luan, Anna; Duscher, Dominik; Whittam, Alexander J.; Paik, Kevin J.; Zielins, Elizabeth R.; Brett, Elizabeth A.; Atashroo, David A.; Hu, Michael S.; Lee, Gordon K.; Gurtner, Geoffrey C.; Longaker, Michael T.; Wan, Derrick C.

    2016-01-01

    Radiation therapy is not only a mainstay in the treatment of many malignancies but also results in collateral obliteration of microvasculature and dermal/subcutaneous fibrosis. Soft tissue reconstruction of hypovascular, irradiated recipient sites through fat grafting remains challenging; however, a coincident improvement in surrounding skin quality has been noted. Cell-assisted lipotransfer (CAL), the enrichment of fat with additional adipose-derived stem cells (ASCs) from the stromal vascular fraction, has been shown to improve fat volume retention, and enhanced outcomes may also be achieved with CAL at irradiated sites. Supplementing fat grafts with additional ASCs may also augment the regenerative effect on radiation-damaged skin. In this study, we demonstrate the ability for CAL to enhance fat graft volume retention when placed beneath the irradiated scalps of immunocompromised mice. Histologic metrics of fat graft survival were also appreciated, with improved structural qualities and vascularity. Finally, rehabilitation of radiation-induced soft tissue changes were also noted, as enhanced amelioration of dermal thickness, collagen content, skin vascularity, and biomechanical measures were all observed with CAL compared to unsupplemented fat grafts. Supplementation of fat grafts with ASCs therefore shows promise for reconstruction of complex soft tissue defects following adjuvant radiotherapy. PMID:26661694

  17. Biodegradability of poly(3-hydroxybutyrate) film grafted with vinyl acetate: Effect of grafting and saponification

    NASA Astrophysics Data System (ADS)

    Wada, Yuki; Seko, Noriaki; Nagasawa, Naotsugu; Tamada, Masao; Kasuya, Ken-ichi; Mitomo, Hiroshi

    2007-06-01

    Radiation-induced graft polymerization of vinyl acetate (VAc) onto poly(3-hydroxybutyrate) (PHB) film was carried out. At a degree of grafting higher than 5%, the grafted films (PHB-g-VAc) completely lost the enzymatic degradability that is characteristic of PHB due to the grafted VAc covering the surface of the PHB film. However, the biodegradability of the PHB-g-VAc films was recovered when the films were saponified in alkali solution under optimum conditions. Graft chains of the PHB-g-VAc film reacted selectively to become biodegradable polyvinyl alcohol (PVA). The biodegradability of the saponified PHB-g-VAc film increased rapidly with time.

  18. Ethylene vinyl acetate based radiation grafted hydrophilic matrices: Process parameter standardization, grafting kinetics and characterization

    NASA Astrophysics Data System (ADS)

    Chaudhari, C. V.; Mondal, R. K.; Dubey, K. A.; Grover, V.; Panicker, L.; Bhardwaj, Y. K.; Varshney, L.

    2016-08-01

    A transparent, elastomeric, grafted matrix for several potential applications was synthesized by single-step simultaneous radiation grafting of methacrylic acid onto ethylene vinyl acetate (EVA). CuSO4 was found to be the most suitable homo-polymerization inhibitor among different inhibitors tried. The grafting kinetics was found to be a strong function of dose rate (D) and monomer content (M) and an equation relating grafting rate Rg=Kg [M]1.13D0.23 was deduced. Crystallinity of the grafted matrices as assessed from XRD and DSC measurements indicated decrease in crystalline content with increase in grafting yield, suggesting crystalline domain of EVA get disrupted on grafting. Elastic modulus increased linearly with the increase in grafting yield, though elongation at break decreased precipitously from 900% to 30% at even ~9% grafting. Thermo-gravimetric analysis showed three step weight loss of the grafted EVA matrix. The grafting of MAA resulted in increase in surface energy mainly due to enhanced polar component.

  19. Xenon treatment protects against cold ischemia associated delayed graft function and prolongs graft survival in rats.

    PubMed

    Zhao, H; Watts, H R; Chong, M; Huang, H; Tralau-Stewart, C; Maxwell, P H; Maze, M; George, A J T; Ma, D

    2013-08-01

    Prolonged hypothermic storage causes ischemia-reperfusion injury (IRI) in the renal graft, which is considered to contribute to the occurrence of the delayed graft function (DGF) and chronic graft failure. Strategies are required to protect the graft and to prolong renal graft survival. We demonstrated that xenon exposure to human proximal tubular cells (HK-2) led to activation of range of protective proteins. Xenon treatment prior to or after hypothermia-hypoxia challenge stabilized the HK-2 cellular structure, diminished cytoplasmic translocation of high-mobility group box (HMGB) 1 and suppressed NF-κB activation. In the syngeneic Lewis-to-Lewis rat model of kidney transplantation, xenon exposure to donors before graft retrieval or to recipients after engraftment decreased caspase-3 expression, localized HMGB-1 within nuclei and prevented TLR-4/NF-κB activation in tubular cells; serum pro-inflammatory cytokines IL-1β, IL-6 and TNF-α were reduced and renal function was preserved. Xenon treatment of graft donors or of recipients prolonged renal graft survival following IRI in both Lewis-to-Lewis isografts and Fischer-to-Lewis allografts. Xenon induced cell survival or graft functional recovery was abolished by HIF-1α siRNA. Our data suggest that xenon treatment attenuates DGF and enhances graft survival. This approach could be translated into clinical practice leading to a considerable improvement in long-term graft survival.

  20. Thermal stability of grafted fibers. [Gamma radiation

    SciTech Connect

    Sundardi, F.; Kadariah; Marlianti, I.

    1983-10-01

    Presented the experimental results on the study of thermal stability of grafted fibers, i.e., polypropylene-, polyester-, and rayon-grafted fibers. These fibers were obtained by radiation grafting processes using hydrophylic monomers such as 1-vinyl 2-pyrolidone, acrylic acid, N-methylol acrylamide, and acrylonitrile. The thermal stability of the fibers was studied using a Shimadzu Thermal Analyzer DT-30. The thermal stability of the fibers, which can be indicated by the value of the activation energy for thermal degradation, was not improved by radiation grafting. The degree of improvement depends on the thermal stability of the monomers used for grafting. The thermal stability of a polypropylene fiber, either a grafted or an ungrafted one, was found to be inferior compared to the polyester of a rayon fiber, which may be due to the lack of C=O and C=C bonds in the polypropylene molecules. The thermal stability of a fiber grafted with acrylonitrile monomer was found to be better than that of an ungrafted one. However, no improvement was detected in the fibers grafted with 1-vinyl 2-pyrrolidone monomer, which may be due to the lower thermal stability of poly(1-vinyl-2-pyrrolidone), compared to the polypropylene or polyester fibers. 17 figures, 3 tables.

  1. Intraoperative anterior cruciate ligament graft contamination.

    PubMed

    Pasque, Charles B; Geib, Timothy M

    2007-03-01

    Intraoperative anterior cruciate ligament graft contamination is a rare but potentially devastating occurrence for any surgeon to encounter. Most instances in our experience have happened when a surgeon first enters practice or is operating in a new environment with new staff. Based on the currently available literature and the senior author's personal experience with 3 cases, intraoperative cleansing of the graft followed by implantation is a reasonable option. The protocol used successfully in these 3 cases includes getting the graft off of the floor immediately, removing any suture material in the graft, cleansing the graft for 15 to 30 minutes each in chlorohexidine and triple antibiotic solution, followed by a normal saline rinse. All graft sutures should then be replaced. The graft should then be resized and the tibial and femoral tunnels adjusted if needed. After implantation of the graft, additional intraoperative and postoperative intravenous antibiotic and/or oral antibiotic administration is also recommended for the first 1 to 2 weeks. Close clinical follow-up is also very important the first 6 weeks postoperatively and should include candid communication with the patient and family.

  2. Mycobacterium chelonei infection of a corneal graft.

    PubMed Central

    Aylward, G. W.; Stacey, A. R.; Marsh, R. J.

    1987-01-01

    We present a case of Mycobacterium chelonei infection in a corneal graft. The chronic ulceration and stromal infiltration followed a well defined course and eventually responded to topical amikacin, though a further graft was required. Previous cases of keratitis due to the M. fortuitum complex are reviewed. Images PMID:3311141

  3. Spreader Grafts in Functional Rhinoplasty.

    PubMed

    Kim, Leslie; Papel, Ira D

    2016-02-01

    Management of the middle vault is paramount to achieving optimal aesthetic and functional outcomes in rhinoplasty. The ideal treatment for middle vault complications, such as internal nasal valve collapse, inverted-V deformity, and middle vault dorsal asymmetry, is prevention. Risk factors for middle vault problems in rhinoplasty that may be identified in preoperative consultation include short nasal bones, long and weak upper lateral cartilages, thin skin, previous trauma or surgery, preoperative positive Cottle maneuver, tension nose deformity, and anteriorly positioned inferior turbinates. When any of these risk factors are identified, preventive measures should be pursued. These include preservation of middle vault support structures, judicious resection in dorsal hump reduction, use of conservative osteotomies, and reconstruction of the cartilaginous middle vault with structural grafting. Spreader grafts have become the workhorse in middle vault reconstruction. They are invaluable in restoring nasal dorsal aesthetic lines, repairing or maintaining the internal nasal valve, and buttressing a corrected crooked nose. Functional and aesthetic problems related to the middle nasal vault are among the most common reasons for patients seeking revision rhinoplasty. Although complications in rhinoplasty are inevitable, underlying their etiology and instituting prophylactic treatment can significantly help reduce their occurrence.

  4. Electrostrictive Graft Elastomers and Applications

    NASA Technical Reports Server (NTRS)

    Su, J.; Harrison, J. S.; St.Clair, T. L.; Bar-Cohen, Y.; Leary, S.

    1999-01-01

    Efficient actuators that are lightweight, high performance and compact are needed to support telerobotic requirements for future NASA missions. In this work, we present a new class of electromechanically active polymers that can potentially be used as actuators to meet many NASA needs. The materials are graft elastomers that offer high strain under an applied electric field. Due to its higher mechanical modulus, this elastomer also has a higher strain energy density as compared to previously reported electrostrictive polyurethane elastomers. The dielectric, mechanical and electromechanical properties of this new electrostrictive elastomer have been studied as a function of temperature and frequency. Combined with structural analysis using x-ray diffraction and differential scanning calorimetry on the new elastomer, structure-property interrelationship and mechanisms of the electric field induced strain in the graft elastomer have also been investigated. This electroactive polymer (EAP) has demonstrated high actuation strain and high mechanical energy density. The combination of these properties with its tailorable molecular composition and excellent processability makes it attractive for a variety of actuation tasks. The experimental results and applications will be presented.

  5. [Autologous fat grafting and rhinoplasty].

    PubMed

    Nguyen, P S; Baptista, C; Casanova, D; Bardot, J; Magalon, G

    2014-12-01

    Revision rhinoplasty can be very challenging especially in cases of thin skin. Autologous fat graft is utilized in numerous applications in plastic surgery; however, its use relative to the nasal region remains uncommon. Adipose tissue, by virtue of its volumetric qualities and its action on skin trophicity, can be considered to be a gold standard implant. From 2006 until 2012, we have treated patients by lipofilling in order to correct sequelae of rhinoplasty. The mean quantity of adipose tissue injected was 2.1cm(3) depending on the importance of the deformity and the area of injection: irregularity of the nasal dorsum, visible lateral osteotomies, saddle nose. Following the course of our practice, we conceived micro-cannulas that allow a much greater accuracy in the placement of the graft and enable to perform interventions under local anesthesia. These non-traumatic micro-cannulas do not cause post-operative ecchymosis and swelling which shorten the recovery time for the patient. On patients who have undergone multiple operations, lipofilling can be a simple and reliable alternative to correct imperfections that may take place after a rhinoplasty.

  6. Coaxial electrospinning multicomponent functional controlled-release vascular graft: Optimization of graft properties.

    PubMed

    Yin, Anlin; Luo, Rifang; Li, Jiukai; Mo, Xiumei; Wang, Yunbing; Zhang, Xingdong

    2017-04-01

    Small diameter vascular grafts possessing desirable biocompatibility and suitable mechanical properties have become an urgent clinic demand. Herein, heparin loaded fibrous grafts of collagen/chitosan/poly(l-lactic acid-co-ε-caprolactone) (PLCL) were successfully fabricated via coaxial electrospinning. By controlling the concentration of heparin and the ratio of collagen/chitosan/PLCL, most grafts had the heparin encapsulation efficiency higher than 70%, and the heparin presented sustained release for more than 45 days. Particularly, such multicomponent grafts had relative low initial burst release, and after heparin releasing for 3 weeks, the grafts still showed good anti-platelet adhesion ability. In addition, along with the excellent cell biocompatibility, the fabricated grafts possessed suitable mechanical properties including good tensile strength, suture retention strength, burst pressure and compliance which could well match the native blood vessels. Thus, the optimized graft properties could be properly addressed for vascular tissue application via coaxial electrospinning.

  7. Intestinal helminths regulate lethal acute graft-versus-host disease and preserve the graft-versus-tumor effect in mice.

    PubMed

    Li, Yue; Chen, Hung-Lin; Bannick, Nadine; Henry, Michael; Holm, Adrian N; Metwali, Ahmed; Urban, Joseph F; Rothman, Paul B; Weiner, George J; Blazar, Bruce R; Elliott, David E; Ince, M Nedim

    2015-02-01

    Donor T lymphocyte transfer with hematopoietic stem cells suppresses residual tumor growth (graft-versus-tumor [GVT]) in cancer patients undergoing bone marrow transplantation (BMT). However, donor T cell reactivity to host organs causes severe and potentially lethal inflammation called graft-versus-host disease (GVHD). High-dose steroids or other immunosuppressive drugs are used to treat GVHD that have limited ability to control the inflammation while incurring long-term toxicity. Novel strategies are needed to modulate GVHD, preserve GVT, and improve the outcome of BMT. Regulatory T cells (Tregs) control alloantigen-sensitized inflammation of GVHD, sustain GVT, and prevent mortality in BMT. Helminths colonizing the alimentary tract dramatically increase the Treg activity, thereby modulating intestinal or systemic inflammatory responses. These observations led us to hypothesize that helminths can regulate GVHD and maintain GVT in mice. Acute GVHD was induced in helminth (Heligmosomoides polygyrus)-infected or uninfected BALB/c recipients of C57BL/6 donor grafts. Helminth infection suppressed donor T cell inflammatory cytokine generation and reduced GVHD-related mortality, but maintained GVT. H. polygyrus colonization promoted the survival of TGF-β-generating recipient Tregs after a conditioning regimen with total body irradiation and led to a TGF-β-dependent in vivo expansion/maturation of donor Tregs after BMT. Helminths did not control GVHD when T cells unresponsive to TGF-β-mediated immune regulation were used as donor T lymphocytes. These results suggest that helminths suppress acute GVHD using Tregs and TGF-β-dependent pathways in mice. Helminthic regulation of GVHD and GVT through intestinal immune conditioning may improve the outcome of BMT.

  8. Modifying glass fiber surface with grafting acrylamide by UV-grafting copolymerization for preparation of glass fiber reinforced PVDF composite membrane.

    PubMed

    Luo, Nan; Zhong, Hui; Yang, Min; Yuan, Xing; Fan, Yaobo

    2016-01-01

    Experimental design and response surface methodology (RSM) were used to optimize the modification of conditions for glass surface grafting with acrylamide (AM) monomer for preparation of a glass fiber reinforced poly(vinylidene fluoride) (PVDF) composite membrane (GFRP-CM). The factors considered for experimental design were the UV (ultraviolet)-irradiation time, the concentrations of the initiator and solvent, and the kinds and concentrations of the silane coupling agent. The optimum operating conditions determined were UV-irradiation time of 25 min, an initiator concentration of 0-0.25 wt.%, solvent of N-Dimethylacetamide (DMAC), and silane coupling agent KH570 with a concentration of 7 wt.%. The obtained optimal parameters were located in the valid region and the experimental confirmation tests conducted showed good accordance between predicted and experimental values. Under these optimal conditions, the water absorption of the grafted modified glass fiber was improved from 13.6% to 23%; the tensile strength was enhanced and the peeling strength of the glass fiber reinforced PVDF composite membrane was improved by 23.7% and 32.6% with an AM concentration at 1 wt.% and 2 wt.%. The surface composition and microstructure of AM grafted glass fiber were studied via several techniques including Field Emission Scanning Electron Microscopy (FESEM), Fourier transform infrared spectroscopy-attenuated total reflectance (FTIR-ATR) and energy dispersive X-ray spectroscopy (EDX). The analysis of the EDX and FTIR-ATR results confirmed that the AM was grafted to the glass fiber successfully by detecting and proving the existence of nitrogen atoms in the GFRP-CM.

  9. Confounding Factors Affecting the National Institutes of Health (NIH) Chronic Graft-Versus-Host Disease Organ-Specific Score and Global Severity

    PubMed Central

    Aki, Sahika Zeynep; Inamoto, Yoshihiro; Carpenter, Paul A.; Storer, Barry E.; Sandmaier, Brenda M.; Lee, Stephanie J.; Martin, Paul J.; Flowers, Mary E.D.

    2016-01-01

    The 2005 NIH chronic graft-versus-host disease (cGVHD) organ severity is based on the assessment of current status regardless of whether abnormalities are due to GVHD. The score assignment does not require knowledge of past manifestations, attribution, or whether cGVHD is still active. The aim of this study is to describe confounding factors affecting organ scores in patients with cGVHD. The study included 189 consecutive cGVHD patients evaluated at our center in 2013. Providers completed the NIH 0–3 organ-specific scoring evaluation with two questions added for each organ to identify abnormalities that were 1) not attributed to cGVHD, or 2) attributed to cGVHD plus other causes. Abnormalities attributed to causes other than GVHD were recorded. Eighty (14%) abnormalities were not attributed to cGVHD in at least one organ, and 41 (7%) abnormalities were attributed to cGVHD plus other causes in at least one organ. A total of 436 (78%) abnormalities were attributed only to cGVHD. Abnormalities not attributed to cGVHD were observed most frequently in the lung, gastrointestinal tract and skin. Most common abnormalities included pre-transplant condition, sequelae from GVHD, deconditioning, infections and medications. Our results support the the 2014 NIH consensus recommendation to consider attribution when scoring organ abnormalities. PMID:27214071

  10. Effect of irradiation on the prevulcanized latex/low nitrosamines latex blends

    SciTech Connect

    Ibrahim, Pairu; Zin, Wan Manshol Wan; Daik, Rusli

    2015-09-25

    Radiation Prevulcanized Natural Rubber Latex (RVNRL) was blended with Low Nitrosamines Latex (LNL) at different composition ratio. Methyl Metachrylate (MMA) was added for grafting onto the blended latex. Blended latex was subjected to gamma irradiation at various doses up to 8kGy. The mechanical properties and FTIR analysis were investigated as a function of the blended composition and irradiation dose. It was found that blending at specific ratio and gamma irradiation at specific dose led to significant improvement on the properties of the latex. The optimum mechanical properties was attained at a total blending ratio of 70% RVNRL and 30% of LNL.

  11. Effect of irradiation on the prevulcanized latex/low nitrosamines latex blends

    NASA Astrophysics Data System (ADS)

    Ibrahim, Pairu; Daik, Rusli; Zin, Wan Manshol Wan

    2015-09-01

    Radiation Prevulcanized Natural Rubber Latex (RVNRL) was blended with Low Nitrosamines Latex (LNL) at different composition ratio. Methyl Metachrylate (MMA) was added for grafting onto the blended latex. Blended latex was subjected to gamma irradiation at various doses up to 8kGy. The mechanical properties and FTIR analysis were investigated as a function of the blended composition and irradiation dose. It was found that blending at specific ratio and gamma irradiation at specific dose led to significant improvement on the properties of the latex. The optimum mechanical properties was attained at a total blending ratio of 70% RVNRL and 30% of LNL.

  12. Polyethylene oxide hydration in grafted layers

    NASA Astrophysics Data System (ADS)

    Dormidontova, Elena; Wang, Zilu

    Hydration of water soluble polymers is one of the key-factors defining their conformation and properties, similar to biopolymers. Polyethylene oxide (PEO) is one of the most important biomedical-applications polymers and is known for its reverse temperature solubility due to hydrogen bonding with water. As in many practical applications PEO chains are grafted to surfaces, e.g. of nanoparticles or planar surfaces, it is important to understand PEO hydration in such grafted layers. Using atomistic molecular dynamic simulations we investigate the details of molecular conformation and hydration of PEO end-grafted to gold surfaces. We analyze polymer and water density distribution as a function of distance from the surface for different grafting densities. Based on a detailed analysis of hydrogen bonding between polymer and water in grafted PEO layers, we will discuss the extent of PEO hydration and its implication for polymer conformation, mobility and layer properties. This research is supported by NSF (DMR-1410928).

  13. Human acellular dermal matrix grafts for rhinoplasty.

    PubMed

    Sherris, David A; Oriel, Brad S

    2011-09-01

    Rhinoplasty often relies on graft material for structural support in the form of cartilage, bone grafts, or fascia. In addition, pliable grafts are often helpful for contouring and can function as a barrier. Unfortunately, grafts carry the disadvantage of requiring an additional donor site, with associated complications. Human acellular dermal matrix (ADM) biological implants offer an exciting alternative for structural support and nonstructural implantation in rhinoplasty procedures. To examine the efficacy of ADM placement in rhinoplasty and septoplasty, the authors report the results from a series of 51 patients. In this series, there were no cases of infection, skin discoloration, seroma formation, septal perforation, significant resorption, extrusion, or other complications related to ADM placement. Therefore, the authors believe that ADM offers a safe and effective alternative to traditional grafting methods for functional and aesthetic rhinoplasty.

  14. Operative strategies in aortic graft infections: is complete graft excision always necessary?

    PubMed

    Hart, Joseph P; Eginton, Mark T; Brown, Kellie R; Seabrook, Gary R; Lewis, Brian D; Edmiston, Charles E; Towne, Jonathan B; Cambria, Robert A

    2005-03-01

    The classic approach to aortic graft infections involves complete excision of the graft material with remote reconstruction of the distal circulation. Certain patients may not be well suited for this approach for physiologic or anatomic reasons. This study was undertaken to determine the outcome of partial graft excision in selected patients with aortic graft infection who were not felt to be candidates for complete graft excision. Retrospective analysis of 30 consecutive patients treated with infected grafts arising from the aorta over the past 10 years was performed. Mean interval between graft placement and infection was 5.5 years. Complete graft excision with bypass via clean tissue planes was achieved in 15 patients (group A), and partial or complete graft salvage or in situ graft replacement was performed at the discretion of the surgeon in 15 patients (group B). Perioperative mortality occurred in eight subjects (27%), including six in group A (40%) and two in group B (13%; p = NS). Six patients (20%) developed recurrent infection following graft excision, two (13%) in group A and four (27%) in group B (p = NS). Microorganisms were recovered from 24 of 30 (80%) graft cultures: 13 (43%) were gram positive, 4 (13%) were gram negative, and both gram-positive and gram-negative organisms were recovered from 7 (23%). Identification of culture isolates did not influence either perioperative mortality or the development of recurrent infection. Long-term survival was no different between the groups. We conclude that in certain high-risk patients who may not tolerate complete graft excision, local resection of infected graft segments may be preferable and leads to similar short- and long-term outcome.

  15. Oxidative product formation in irradiated neutrophils. A flow cytometric analysis

    SciTech Connect

    Wolber, R.A.; Duque, R.E.; Robinson, J.P.; Oberman, H.A.

    1987-03-01

    The effect of irradiation on neutrophil oxidative function was evaluated using a flow cytometric assay of intracellular hydrogen peroxide (H/sub 2/O/sub 2/) production. This assay quantitates the H/sub 2/O/sub 2/-dependent conversion of the nonfluorescent compound, 2'-7'-dichlorofluorescein (DCFH), into fluorescent 2'-7'-dichlorofluorescein (DCF) on a single-cell basis. Intracellular H/sub 2/O/sub 2/ production in response to stimulation with phorbol myristate acetate was not affected by neutrophil irradiation at doses up to 2500 rad. In addition, irradiation of intracellular DCFH and aqueous 2'-7'-dichlorofluorescein diacetate (DCFH-DA) resulted in DCF production, which suggested that oxidative molecules produced by aqueous radiolysis were detected by this assay. This study indicates that radiation doses of 1500 to 2500 rad, which are sufficient to prevent induction of graft-versus-host disease by transfused blood components, are not deleterious to neutrophil oxidative metabolism.

  16. [How to handle unexpected biological abnormalities observed in the pre-donation workup for hematopoietic stem cell transplantation: an SFGM-TC report on pre-transplant cytomegalovirus, Epstein-Barr virus, Toxoplasma gondii, or syphilis IgM positive serology test].

    PubMed

    Duléry, R; Giraud, C; Beaumont, J-L; Bilger, K; Borel, C; Dhedin, N; Thiebaut, A; Willems, E; Alain, S; Alfandari, S; Dewilde, A; Jouet, J-P; Milpied, N; Yakoub-Agha, I

    2013-08-01

    In the attempt to harmonize clinical practices between different French transplantation centers, the French Society of Bone Marrow Transplantation and Cell Therapy (SFGM-TC) set up the third annual series of workshops which brought together practitioners from all member centers and took place in October 2012 in Lille. Here we report our results and recommendations regarding the management of pre-transplant donor's cytomegalovirus, Epstein-Barr virus, Toxoplasma gondii, or syphilis IgM positive serology test.

  17. Polyvinyl alcohol {gamma}-ray grafted nylon 4 membrane for pervaporation and evapomeation

    SciTech Connect

    Lai, J.Y.; Chen, R.Y.; Lee, K.R

    1993-05-01

    Nylon 4, which possesses high mechanical strength and good affinity for water, can be considered as a liquid separation membrane. To improve the hydrophilicity of a Nylon 4 membrane for pervaporation and evapomeation processes, and to overcome the hydrolysis of polyvinyl alcohol (PVA), this study attempts to prepare a PVA-g-Nylon 4 membrane by {gamma}-ray irradiation grafting of vinyl acetate (VAc) onto Nylon 4 membrane, followed by hydrolysis treatment. The effects of down-stream pressure, irradiation dose, VAc monomer concentration, degree of grafting, feed composition, and size of alcohols on the separation of water-alcohol mixtures were studied. The surface properties of the prepared membrane were characterized by FTIR, ESCA, and a contact angle meter. A separation factor of 13.8 and a permeation rate of 0.352 kg/m{sup 2}-h can be obtained for a PVA-g-Nylon 4 membrane with a degree of grafting of 21.2% for a 90-wt% ethanol feed concentration. Compared to the pervaporation process, the evapomeation process has a significantly increased separation factor with a decreased permeation rate for the same PVA-g-Nylon 4 membrane. 24 refs., 9 figs., 4 tabs.

  18. Prolonged heart xenograft survival using combined total lymphoid irradiation and cyclosporine

    SciTech Connect

    Knechtle, S.J.; Halperin, E.C.; Saad, T.; Bollinger, R.R.

    1986-05-01

    Total lymphoid irradiation and cyclosporine have profound immunosuppressive properties and permit successful heart allotransplantation. Cyclosporine used alone has not permitted consistently successful transplantation between species in all cases. Total lymphoid irradiation has not been applied to xenotransplantation. The efficacy of total lymphoid irradiation alone and in combination with cyclosporine was examined using an animal model of heart xenotransplantation. Heterotopic heart transplants were performed using inbred Syrian hamsters as donors and Lewis rats as recipients. Total lymphoid irradiation was administered preoperatively over 3 weeks for a total dose of 15 gray. Cyclosporine was started on the day of surgery and was given as a daily intramuscular injection of 2.5, 5, or 10 mg/kg/day until rejection was complete. Neither total lymphoid irradiation nor cyclosporine alone markedly prolonged graft survival. However, combined total lymphoid irradiation and cyclosporine, 5 or 10 mg/kg/day, dramatically prolonged graft survival to greater than 100 days in most recipients. There were no treatment-related deaths. In conclusion, combined total lymphoid irradiation and cyclosporine permit successful long-term survival of heart xenotransplants in this hamster-to-rat model.

  19. Prognostic factors for corneal graft recovery after severe corneal graft rejection following penetrating keratoplasty

    PubMed Central

    2013-01-01

    Background To investigate the outcome and prognostic factors for corneal graft recovery after severe corneal graft rejection following penetrating keratoplasty (PKP) treated with topical and systemic steroids. Methods Fifty-eight eyes in 58 patients with severe corneal graft rejection following PKP were treated with topical and systemic steroids. Factors affecting the reversibility and maintenance of graft transparency were analyzed. Results Graft transparency was restored in 37 of 58 eyes (63.8%). Clarity of the graft was maintained in 25 of 37 eyes after transparency was restored, while corneal decompensation developed at a mean of 6.0 ± 4.3 months in the remainder. The interval between rejection and treatment with systemic steroids was shorter in cases that recovered graft transparency (OR, 0.88, 95% CI. 0.80–0.97, P = 0.0093). Corneal decompensation after the recovery of corneal transparency tend to occur in cases of regraft (OR, 0.09, 95% CI. 0.01–0.54, P = 0.0091). Conclusions Severe corneal graft rejection after PKP was reversible in approximately two-thirds of the cases, with graft transparency being maintained in two-thirds of them when treated with both topical and systemic steroids. Early treatment confers a benefit in terms of the recovery of graft transparency. PMID:23432898

  20. Evaluation of synthetic vascular grafts in a mouse carotid grafting model

    PubMed Central

    Tan, Richard P.; Michael, Praveesuda L.; Lee, Bob S. L.; Vanags, Laura Z.; Ng, Martin K. C.; Bursill, Christina A.; Wise, Steven G.

    2017-01-01

    Current animal models for the evaluation of synthetic grafts are lacking many of the molecular tools and transgenic studies available to other branches of biology. A mouse model of vascular grafting would allow for the study of molecular mechanisms of graft failure, including in the context of clinically relevant disease states. In this study, we comprehensively characterise a sutureless grafting model which facilitates the evaluation of synthetic grafts in the mouse carotid artery. Using conduits electrospun from polycaprolactone (PCL) we show the gradual development of a significant neointima within 28 days, found to be greatest at the anastomoses. Histological analysis showed temporal increases in smooth muscle cell and collagen content within the neointima, demonstrating its maturation. Endothelialisation of the PCL grafts, assessed by scanning electron microscopy (SEM) analysis and CD31 staining, was near complete within 28 days, together replicating two critical aspects of graft performance. To further demonstrate the potential of this mouse model, we used longitudinal non-invasive tracking of bone-marrow mononuclear cells from a transgenic mouse strain with a dual reporter construct encoding both luciferase and green fluorescent protein (GFP). This enabled characterisation of mononuclear cell homing and engraftment to PCL using bioluminescence imaging and histological staining over time (7, 14 and 28 days). We observed peak luminescence at 7 days post-graft implantation that persisted until sacrifice at 28 days. Collectively, we have established and characterised a high-throughput model of grafting that allows for the evaluation of key clinical drivers of graft performance. PMID:28355300

  1. Adaptive significance of root grafting in trees

    SciTech Connect

    Loehle, C.; Jones, R.

    1988-12-31

    Root grafting has long been observed in forest trees but the adaptive significance of this trait has not been fully explained. Various authors have proposed that root grafting between trees contributes to mechanical support by linking adjacent root systems. Keeley proposes that this trait would be of greatest advantage in swamps where soils provide poor mechanical support. He provides as evidence a greenhouse study of Nyssa sylvatica Marsh in which seedlings of swamp provenance formed between-individual root grafts more frequently than upland provenance seedlings. In agreement with this within-species study, Keeley observed that arid zone species rarely exhibit grafts. Keeley also demonstrated that vines graft less commonly than trees, and herbs never do. Since the need for mechanical support coincides with this trend, these data seem to support his model. In this paper, the authors explore the mechanisms and ecological significance of root grafting, leading to predictions of root grafting incidence. Some observations support and some contradict the mechanical support hypothesis.

  2. Grafted dopamine neurons: Morphology, neurochemistry, and electrophysiology.

    PubMed

    Strömberg, Ingrid; Bickford, Paula; Gerhardt, Greg A

    2010-02-09

    Grafting of dopamine-rich tissue to counteract the symptoms in Parkinson's disease became a promising tool for future treatment. This article discusses how to improve the functional outcome with respect to graft outgrowth and functions of dopamine release and electrophysiological responses to graft implantation in the host brain striatal target. It has been documented that a subpopulation of the dopamine neurons innervates the host brain in a target-specific manner, while some of the grafted dopamine neurons never project to the host striatum. Neurochemical studies have demonstrated that the graft-induced outgrowth synthesize, store, metabolize and release dopamine and possibly other neurotransmitters such as 5-HT. Furthermore, the released dopamine affects the dopamine-depleted brain in areas that are larger than the graft-derived nerve fibers reach. While stem cells will most likely be the future source of cells to be used in grafting, it is important to find the guiding cues for how to reinnervate the dopamine-depleted striatum in a proper way with respect to the dopamine subpopulations of A9 and A10 to efficiently treat the motor abnormalities seen in Parkinson's disease.

  3. Polypeptide Grafted Hyaluronan: Synthesis and Characterization

    PubMed Central

    Wang, Xiaojun; Messman, Jamie; Mays, Jimmy W.; Baskaran, Durairaj

    2010-01-01

    Poly(L-leucine) grafted hyaluronan (HA-g-PLeu) has been synthesized via a Michael addition reaction between primary amine terminated poly(L-leucine) and acrylate functionalized HA (TBAHA-acrylate). The precursor hyaluronan was first functionalized with acrylate groups by reaction with acryloyl chloride in the presence of triethylamine in N,N-dimethylformamide. 1H NMR analysis of the resulting product indicated that an increase in the concentration of acryloylchoride with respect to hydroxyl groups on HA has only a moderate effect on functionalization efficiency, f. A precise control of stoichiometry was not achieved, which could be attributed to partial solubility of intermolecular aggregates and the hygroscopic nature of HA. Michael addition at high [PLeu-NH2]/[acrylate]TBAHA ratios gave a molar grafting ratio of only 0.20 with respect to the repeat unit of HA, indicating grafting limitation due to insolubility of the grafted HA-g-PLeu. Soluble HA-g-PLeu graft copolymers were obtained for low grafting ratios (< 0.039) with < 8.6 % by mass of PLeu and were characterized thoroughly using light scattering, 1H NMR, FT-IR and AFM techniques. Light scattering experiments showed a strong hydrophobic interaction between PLeu chains, resulting in aggregates with segregated non-grafted HA segments. This yields local networks of aggregates as demonstrated by atomic force microscopy. Circular dichroism spectroscopy showed a β-sheet conformation for aggregates of poly(L-leucine). PMID:20690642

  4. Pre-transplant prognostic factors of long-term survival after allogeneic peripheral blood stem cell transplantation with matched related/unrelated donors

    PubMed Central

    Servais, Sophie; Porcher, Raphaël; Xhaard, Alienor; Robin, Marie; Masson, Emeline; Larghero, Jerome; Ribaud, Patricia; Dhedin, Nathalie; Abbes, Sarah; Sicre, Flore; Socié, Gérard; de Latour, Regis Peffault

    2014-01-01

    Mobilized peripheral blood has become the predominant stem cell source for allogeneic hematopoietic cell transplantation. In this retrospective single center study of 442 patients with hematologic malignancies, we analyzed prognostic factors for long-term survival after peripheral blood stem cell transplantation from HLA-matched related or unrelated donors. To account for disease/status heterogeneity, patients were risk-stratified according to the Disease Risk Index. Five-year overall survival was similar after transplants with matched related and unrelated donors (45% and 46%, respectively; P=0.49). Because donor age ≥60 years impacted outcome during model building, we further considered 3 groups of donors: matched unrelated (aged <60 years by definition), matched related aged <60 years and matched related aged ≥60 years. In multivariate analysis, the donor type/age group and the graft CD34+ and CD3+ cell doses impacted long-term survival. Compared with matched unrelated donor transplant, transplant from matched related donor <60 years resulted in similar long-term survival (P=0.67) while transplant from matched related donor ≥60 years was associated with higher risks for late mortality (hazard ratio (HR) 4.41; P=0.006) and treatment failure (HR: 6.33; P=0.009). Lower mortality risks were observed after transplant with CD34+ cell dose more than 4.5×106/kg (HR: 0.56; P=0.002) and CD3+ cell dose more than 3×108/kg (HR: 0.61; P=0.01). The Disease Risk Index failed to predict survival. We built an “adapted Disease Risk Index” by modifying risks for myeloproliferative neoplasms and multiple myeloma that improved stratification ability for progression-free survival (P=0.04) but not for overall survival (P=0.82). PMID:24241489

  5. Pre-transplant prognostic factors of long-term survival after allogeneic peripheral blood stem cell transplantation with matched related/unrelated donors.

    PubMed

    Servais, Sophie; Porcher, Raphaël; Xhaard, Alienor; Robin, Marie; Masson, Emeline; Larghero, Jerome; Ribaud, Patricia; Dhedin, Nathalie; Abbes, Sarah; Sicre, Flore; Socié, Gérard; Peffault de Latour, Regis

    2014-03-01

    Mobilized peripheral blood has become the predominant stem cell source for allogeneic hematopoietic cell transplantation. In this retrospective single center study of 442 patients with hematologic malignancies, we analyzed prognostic factors for long-term survival after peripheral blood stem cell transplantation from HLA-matched related or unrelated donors. To account for disease/status heterogeneity, patients were risk-stratified according to the Disease Risk Index. Five-year overall survival was similar after transplants with matched related and unrelated donors (45% and 46%, respectively; P=0.49). Because donor age ≥60 years impacted outcome during model building, we further considered 3 groups of donors: matched unrelated (aged <60 years by definition), matched related aged <60 years and matched related aged ≥60 years. In multivariate analysis, the donor type/age group and the graft CD34(+) and CD3(+) cell doses impacted long-term survival. Compared with matched unrelated donor transplant, transplant from matched related donor <60 years resulted in similar long-term survival (P=0.67) while transplant from matched related donor ≥60 years was associated with higher risks for late mortality (hazard ratio (HR) 4.41; P=0.006) and treatment failure (HR: 6.33; P=0.009). Lower mortality risks were observed after transplant with CD34(+) cell dose more than 4.5×10(6)/kg (HR: 0.56; P=0.002) and CD3(+) cell dose more than 3×10(8)/kg (HR: 0.61; P=0.01). The Disease Risk Index failed to predict survival. We built an "adapted Disease Risk Index" by modifying risks for myeloproliferative neoplasms and multiple myeloma that improved stratification ability for progression-free survival (P=0.04) but not for overall survival (P=0.82).

  6. Surface modification of polyethylene film by acrylamide graft and alcoholysis for improvement of antithrombogenicity

    NASA Astrophysics Data System (ADS)

    Zhao, Guowei; Chen, Yashao; Wang, Xiaoli

    2007-03-01

    To improve antithrombogenicity of polyethylene (PE) films, the films pretreated by Ar plasma were radiated by ultraviolet light to initiate grafting polymerization with acrylamide (AAm) in absence of photo-initiator, then the AAm-grafted PE films (PE-g-AAm) were alcoholized with octadecyl alcohol. Effects of Ar plasma composite parameter ( W/ FM), pretreated time, AAm monomer concentration, and UV irradiation time on grafting rate were investigated systematically. AAm-grafted PE film and alcoholized PE film (PE-g-SAAm) were characterized by contact angle, X-ray photoelectron spectroscopy (XPS), attenuated total reflectance Fourier transfer infrared (ATR-FT-IR) spectroscopy and atomic force microscope (AFM), respectively. The results indicated that the moieties of AAm and stearyl were successively immobilized onto the PE surface. The platelet adhesion experiment showed that antithrombogenicity of the modified PE films was improved in comparison with PE films. The change in antithrombogenicity is attributed to the surface of the modified film in presence of tail-like structure which consists of polyacrylamide as spacer and stearyl as end groups.

  7. One-pot synthesis of fluorescent polysaccharides: adenine grafted agarose and carrageenan.

    PubMed

    Oza, Mihir D; Prasad, Kamalesh; Siddhanta, A K

    2012-08-01

    New fluorescent polysaccharides were synthesized by grafting the nucleobase adenine on to the backbones of agarose and κ-carrageenan, which were characterized by FT-IR, (13)C NMR, TGA, XRD, UV, and fluorescence properties. The synthesis involved a rapid water based potassium persulfate (KPS) initiated method under microwave irradiation. The emission spectra of adenine grafted agarose and κ-carrageenan were recorded in aqueous (5×10(-5) M) solution, exhibiting λ(em,max) 347 nm by excitation at 261 nm, affording ca. 30% and 40% enhanced emission intensities, respectively compared to that of pure adenine solution in the same concentration. Similar emission intensity was recorded in the pure adenine solution at its molar equivalent concentrations present in the 5×10(-5) M solution of the agarose and carrageenan grafted products, that is, 3.28×10(-5) M and 4.5×10(-5) M respectively. These fluorescent adenine grafted products may have potential utility in various sensor applications.

  8. Introduction of anticoagulation group to polypropylene film by radiation grafting and its blood compatibility

    NASA Astrophysics Data System (ADS)

    Mao, Chun; Zhang, Can; Qiu, Yongzhi; Zhu, Aiping; Shen, Jian; Lin, Sicong

    2004-04-01

    Based on in vitro tests for an improvement of the blood compatibility of polypropylene (PP) films by grafting O-butyrylchitosan (OBCS), we prepared a novel biocompatible film. The immobilization was accomplished by irradiating with ultraviolet light, OBCS being coated on the film surface to photolyze azide groups, thus cross-linking OBCS and PP together. The grafted sample films were verified by attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), electron spectroscopy for chemical analysis (ESCA) and the water contact angle measurements. The blood compatibility of the OBCS-grafted PP films was evaluated by platelet rich plasma (PRP) contacting experiments and protein adsorption experiments using blank PP film as the control. It demonstrated that blood compatibility of the OBCS-grafted surfaces is better than that of the blank PP. The suitable modifications could be carried out to tailor PP biomaterial to meet the specific needs of different biomedical applications. These results suggest that the photocrosslinkable chitosan developed here has the potential of serving as a new biomaterial in medical use.

  9. A Reappraisal of Saphenous Vein Grafting

    PubMed Central

    Yuan, Shi-Min; Jing, Hua

    2011-01-01

    Autologous saphenous vein grafting has been broadly used as a bypass conduit, interposition graft, and patch graft in a variety of operations in cardiac, thoracic, neurovascular, general vascular, vascular access, and urology surgeries, since they are superior to prosthetic veins. Modified saphenous vein grafts (SVG), including spiral and cylindrical grafts, and vein cuffs or patches, are employed in vascular revascularization to satisfy the large size of the receipt vessels or to obtain a better patency. A loop SVG helps flap survival in a muscle flap transfer in plastic and reconstructive surgery. For dialysis or transfusion purposes, a straight or loop arteriovenous fistula created in the forearm or the thigh with an SVG has acceptable patency. The saphenous vein has even been used as a stent cover to minimize the potential complications of standard angioplasty technique. However, the use of saphenous vein grafting is now largely diminished in treating cerebrovascular disorders, superior vena cava syndrome, and visceral revascularization due to the introduction of angioplasty and stenting techniques. The SVG remains the preferable biomaterial in coronary artery bypass, coronary ostioplasty, free flap transfer, and surgical treatment of Peyronie disease. Implications associated with saphenous vein grafting in vascular access surgery for the purpose of dialysis and chemotherapy are considerable. Vascular cuffs and patches have been developed as an important and effective means of enhancing the patency rates of the grafts by linking the synthetic material to the receipt vessel. In addition, saphenous veins can be a cell source for tissue engineering. We review the versatile roles that saphenous vein grafting has played as well as its current status in therapy. PMID:21245602

  10. Flow characteristics in narrowed coronary bypass graft

    NASA Astrophysics Data System (ADS)

    Bernad, S. I.; Bosioc, A.; Bernad, E. S.; Petre, I.; Totorean, A. F.

    2016-06-01

    Tortuous saphenous vein graft (SVG) hemodynamics was investigated using computational fluid dynamics (CFD) techniques. Computed tomography (CT) technology is used for non-invasive bypass graft assessment 7 days after surgery. CT investigation shown two regions with severe shape remodelling first is an elbow type contortion and second is a severe curvature with tortuous area reduction. In conclusion, the helical flow induced by vessel torsion may stabilize the blood flow in the distal part of the SVG, reducing the flow disturbance and suppressing the flow separation, but in the distal end of the graft, promote the inflammatory processes in the vessels.

  11. Role of TDTH and Tc populations in organ graft rejection. I. Functional analysis of graft-infiltrating T cells

    SciTech Connect

    Stepkowski, S.M.; Duncan, W.R.

    1986-10-01

    To analyze the role of T cell subpopulations in the rejection of organ allografts, we developed a new model for obtaining large numbers of graft infiltrating cells (GICs). We isolated W3/25+ Th/DTH and OX8+ Ts/c from vascularized, irradiated rat spleen allografts. W3/25+ GICs obtained from spleen allografts transplanted to normal recipients were highly effective in eliciting cardiac allograft rejection when transferred to sublethally irradiated recipients, however, the OX8+ subset was incapable of eliciting rejection. On the other hand, when OX8+ GICs were obtained from spleen allografts transplanted to previously immunized recipients, they were as efficient as the W3/25+ Th/DTH subset in eliciting cardiac allograft destruction. These results indicate that the W3/25+, OX8- T cell is required for the rejection of primary organ allografts, but that the rejection of a secondary allograft by an immune recipient may be mediated, independently, by both W3/25+ and OX8+ cells.

  12. A comparative study on the graft copolymerization of acrylic acid onto rayon fibre by a ceric ion redox system and a γ-radiation method.

    PubMed

    Kaur, Inderjeet; Kumar, Raj; Sharma, Neelam

    2010-10-13

    Functionalization of rayon fibre has been carried out by grafting acrylic acid (AAC) both by a chemical method using a Ce(4+)-HNO(3) redox initiator and by a mutual irradiation (γ-rays) method. The reaction conditions affecting the grafting percentage have been optimized for both methods, and the results are compared. The maximum percentage of grafting (50%) by the chemical method was obtained utilizing 18.24 × 10(-3) moles/L of ceric ammonium nitrate (CAN), 39.68 × 10(-2) moles/L of HNO(3), and 104.08 × 10(-2) moles/L of AAc in 20 mL of water at 45°C for 120 min. For the radiation method, the maximum grafting percentage (60%) was higher, and the product was obtained under milder reaction conditions using a lower concentration of AAc (69.38 × 10(-2) moles/L) in 10 mL of water at an optimum total dose of 0.932 kGy. Swelling studies showed higher swelling for the grafted rayon fibre in water (854.54%) as compared to the pristine fibre (407%), while dye uptake studies revealed poor uptake of the dye (crystal violet) by the grafted fibre in comparison with the pristine fibre. The graft copolymers were characterized by IR, TGA, and scanning electron micrographic methods. Grafted fibre, prepared by the radiation-induced method, showed better thermal behaviour. Comparison of the two methods revealed that the radiation method of grafting of acrylic acid onto rayon fibre is a better method of grafting in comparison with the chemical method.

  13. Comminuting irradiated ferritic steel

    DOEpatents

    Bauer, Roger E.; Straalsund, Jerry L.; Chin, Bryan A.

    1985-01-01

    Disclosed is a method of comminuting irradiated ferritic steel by placing the steel in a solution of a compound selected from the group consisting of sulfamic acid, bisulfate, and mixtures thereof. The ferritic steel is used as cladding on nuclear fuel rods or other irradiated components.

  14. Perspective on food irradiation

    SciTech Connect

    Not Available

    1987-02-01

    Recent US Food and Drug Administration approval of irradiation treatment for fruit, vegetables and pork has stimulated considerable discussion in the popular press on the safety and efficacy of irradiation processing of food. This perspective is designed to summarize the current scientific information available on this issue.

  15. MASSIVE LEAKAGE IRRADIATOR

    DOEpatents

    Wigner, E.P.; Szilard, L.; Christy, R.F.; Friedman, F.L.

    1961-05-30

    An irradiator designed to utilize the neutrons that leak out of a reactor around its periphery is described. It avoids wasting neutron energy and reduces interference with the core flux to a minimum. This is done by surrounding all or most of the core with removable segments of the material to be irradiated within a matrix of reflecting material.

  16. Feasibility of the Use of RapiGraft and Skin Grafting in Reconstructive Surgery

    PubMed Central

    Cho, In Gook; Kwon, Joon Hyun; Lee, Jeong Woo; Choi, Kang Young; Chung, Ho Yun; Cho, Byung Chae

    2016-01-01

    Background Skin grafting is a relatively simple and thus widely used procedure. However, the elastic and structural quality of grafted skin is poor. Recently, various dermal substitutes have been developed to overcome this disadvantage of split-thickness skin grafts. The present study aims to determine the feasibility of RapiGraft as a new dermal substitute. Methods This prospective study included 20 patients with partial- or full-thickness skin defects; the patients were enrolled between January 2013 and March 2014. After skin defect debridement, the wound was divided into two parts by an imaginary line. Split-thickness skin grafting alone was performed on one side (group A), and RapiGraft and split-thickness skin grafting were used on the other side (group B). All patients were evaluated using photographs and self-questionnaires. The Manchester scar scale (MSS), a chromameter, and a durometer were used for the scar evaluation. The average follow-up period was 6 months. Results The skin graft take rates were 93% in group A and 89% in group B, a non-significant difference (P=0.082). Statistically, group B had significantly lower MSS, vascularity, and pigmentation results than group A (P<0.05 for all). However, the groups did not differ significantly in pliability (P=0.155). Conclusions The present study indicates that a simultaneous application of RapiGraft and a split-thickness skin graft is safe and yields improved results. Therefore, we conclude that the use of RapiGraft along with skin grafting will be beneficial for patients requiring reconstructive surgery. PMID:27689048

  17. Radiobiological speculations on therapeutic total body irradiation

    SciTech Connect

    Vriesendorp, H.M. )

    1990-01-01

    Unexpected total body irradiation (TBI) of human beings, involved in nuclear warfare or in accidents in nuclear reactors can be lethal. In the 1950s, bone marrow transplantation was discovered as a potentially life saving procedure after TBI in the dose range of 5.0 to 12.0 Gy. Since that time, deliberate or therapeutic TBI has been used to condition patients with a lethal bone marrow disorder for bone marrow replacement. The therapeutic ratio of TBI followed by bone marrow transplantation is small. Many potentially lethal complications can occur, such as acute TBI side effects, late TBI side effects or immunological complications of bone marrow transplantation such as graft versus host disease or graft rejection. The benefits of TBI and bone marrow transplantation are that they offer a chance for cure of previously lethal bone marrow disorders. The optimal parameters for TBI remain to be defined. The review discusses the current clinical and experimental animal data, as they relate to the future definition of less toxic TBI procedures with a better therapeutic ratio. Different TBI procedures are required for patients with malignant vs. non-malignant disorders or for patients with histoincompatible vs. histocompatible bone marrow donors.77 references.

  18. Nasal reconstruction with articulated irradiated rib cartilage

    SciTech Connect

    Murakami, C.S.; Cook, T.A.; Guida, R.A. )

    1991-03-01

    Nasal structural reconstruction is a formidable task in cases where there is loss of support to both the nasal dorsum and tip. A multitude of surgical approaches and materials have been used for the correction of the saddle-nose deformity with varying degrees of success. Articulated irradiated rib cartilage inserted through an external rhinoplasty approach was used to reconstruct nasal deformities in 18 patients over a 6-year period. Simultaneous use of a midline forehead flap to reconstruct the overlying soft tissue was required in four cases. Follow-up ranged from 1 to 6 years (mean, 2.8 years). Results were rewarding in most cases with marked improvement in nasal support and airway. Revision and/or replacement secondary to trauma or warping of the graft was required in four cases. None of the patients exhibited infection, extrusion, or noticeable resorption. A description of the surgical technique, review of all the cases, and recommendation for continued use of this graft material are discussed.

  19. Self-monitoring bypass grafts enable early intervention

    NASA Astrophysics Data System (ADS)

    Neville, Richard F.; Gupta, Samit K.; Kuraguntla, David J.

    2016-09-01

    Prosthetic grafts used for lower extremity revascularization and dialysis access fail due to hyperplastic stenosis and thrombosis. Graft surveillance is advocated to monitor function, however, graft failure can occur between episodic examinations. An innovative self-monitoring graft system allows automated surveillance with assessment of graft function using a cloud-based algorithm. We performed proof of concept experiments with in vitro and in vivo models to assess the feasibility such a real-time graft surveillance system. Initial in-vitro and in-vivo experiments demonstrate the ability for a self-monitoring graft system to remotely monitor hemodynamic parameters reflecting graft function using wireless data transmission. This automated system shows promise to deliver real-time data that can be analyzed by cloud-based algorithms alerting the clinician of a change in graft function or development of stenosis for further diagnostic study or intervention prior to graft failure.

  20. Irradiation Creep in Graphite

    SciTech Connect

    Ubic, Rick; Butt, Darryl; Windes, William

    2014-03-13

    An understanding of the underlying mechanisms of irradiation creep in graphite material is required to correctly interpret experimental data, explain micromechanical modeling results, and predict whole-core behavior. This project will focus on experimental microscopic data to demonstrate the mechanism of irradiation creep. High-resolution transmission electron microscopy should be able to image both the dislocations in graphite and the irradiation-induced interstitial clusters that pin those dislocations. The team will first prepare and characterize nanoscale samples of virgin nuclear graphite in a transmission electron microscope. Additional samples will be irradiated to varying degrees at the Advanced Test Reactor (ATR) facility and similarly characterized. Researchers will record microstructures and crystal defects and suggest a mechanism for irradiation creep based on the results. In addition, the purchase of a tensile holder for a transmission electron microscope will allow, for the first time, in situ observation of creep behavior on the microstructure and crystallographic defects.

  1. A Highly Thermostable Ceramic-Grafted Microporous Polyethylene Separator for Safer Lithium-Ion Batteries.

    PubMed

    Zhu, Xiaoming; Jiang, Xiaoyu; Ai, Xinping; Yang, Hanxi; Cao, Yuliang

    2015-11-04

    The safety concern is a critical obstacle to large-scale energy storage applications of lithium-ion batteries. A thermostable separator is one of the most effective means to construct the safe lithium-ion batteries. Herein, we demonstrate a novel ceramic (SiO2)-grafted PE separator prepared by electron beam irradiation. The separator shows similar thickness and pore structure to the bare separator, while displaying strong dimensional thermostability, as the shrinkage ratio is only 20% even at an elevated temperature of 180 °C. Besides, the separator is highly electrochemically inert, showing no adverse effect on the energy and power output of the batteries. Considering the excellent electrochemical and thermal stability, the SiO2-grafted PE separator developed in this work is greatly beneficial for constructing safer lithium-ion batteries.

  2. Bio-compatibility of ion beam-modified and RGD-grafted polyethylene

    NASA Astrophysics Data System (ADS)

    Ročková-Hlaváčková, K.; Švorčík, V.; Bačáková, L.; Dvořánková, B.; Heitz, J.; Hnatowicz, V.

    2004-09-01

    Polyethylene (PE) was implanted with 15 keV Ar + and Kr + ions to the fluences from 3 × 10 12-1 × 10 15 cm -2 and subsequently grafted with amino acid sequence Arg-Gly-Asp (RGD), i.e. a minimum adhesion motif recognized by integrin receptors on cells. The structural changes of PE were studied using goniometric technique, UV-VIS, LIF spectroscopy and by measuring specimen electrical resistance. The adhesion and proliferation of mouse embryonic fibroblasts 3T3 on the modified PE were studied under in vitro conditions. Addition of RGD sequence onto double bonds created by the ion irradiation on polymeric chain was observed. The adhesion and proliferation of the 3T3 cells is increased by ion implantation and additionally also by RGD grafting.

  3. Swelling characteristics of konjac glucomannan superabsobent synthesized by radiation-induced graft copolymerization

    NASA Astrophysics Data System (ADS)

    Wu, Jia; Deng, Xiao; Lin, Xiangyang

    2013-02-01

    Graft copolymerization of konjac glucomannan (KGM) and acrylic acid was induced by 60Co-γ irradiation at room temperature. The effects of radiation dose and monomer-to-KGM ratio on grafting yield and equilibrium water absorbency were investigated. The KGM-based superabsorbent polymer (KSAP) could absorb water 625 times of its dry weight when the radiation dose was 5.0 kGy and monomer-to-KGM ratio was 5. The structure of KSAP was characterized by FTIR, XRD, and SEM. KSAP showed a lower crystallinity than KGM. The porous microstructure of KSAP was revealed by SEM. The diffusion mechanism of water in the hydrogel is consistent with the anomalous diffusion model. Cations, especially multivalent cations, greatly reduced water absorbency of KSAP. Rising temperature, acidic or basic solutions are not favorable for the swelling of KSAP.

  4. Subacute radiation dermatitis: a histologic imitator of acute cutaneous graft-versus-host disease

    SciTech Connect

    LeBoit, P.E.

    1989-02-01

    The histopathologic changes of radiation dermatitis have been classified either as early effects (necrotic keratinocytes, fibrin thrombi, and hemorrhage) or as late effects (vacuolar changes at the dermal-epidermal junction, atypical radiation fibroblasts, and fibrosis). Two patients, one exposed to radiation therapeutically and one accidentally, are described. Skin biopsy specimens showed an interface dermatitis characterized by numerous dyskeratotic epidermal cells with lymphocytes in close apposition (satellite cell necrosis); that is, the epidermal changes were similar to those in acute graft-versus-host disease. Because recipients of bone marrow transplants frequently receive total body irradiation as part of their preparatory regimen, the ability of radiation to cause persistent epidermal changes similar to those in acute graft-versus-host disease could complicate the interpretation of posttransplant skin biopsy specimens.

  5. Chemical and radiation crosslinked polymer electrolyte membranes prepared from radiation-grafted ETFE films for DMFC applications

    NASA Astrophysics Data System (ADS)

    Chen, Jinhua; Asano, Masaharu; Yamaki, Tetsuya; Yoshida, Masaru

    To develop a highly chemically stable polymer electrolyte membrane for application in a direct methanol fuel cell (DMFC), doubly crosslinked membranes were prepared by chemical crosslinking using bifunctional monomers, such as divinylbenzene (DVB) and bis(p, p-vinyl phenyl) ethane (BVPE), and by radiation crosslinking. The membranes were prepared by grafting of m, p-methylstyrene (MeSt) and p-tert-butylstyrene (tBuSt) into poly(ethylene- co-tetrafluoroethylene) (ETFE) films and subsequent sulfonation. The effects of the DVB and BVPE crosslinkers on the grafting kinetics and the properties of the prepared membranes, such as water uptake, proton conductivity and chemical stability were investigated. Radiation crosslinking was introduced by irradiation of the ETFE base film, the grafted film or the sulfonated membrane. The membrane crosslinked by DVB and BVPE crosslinkers and post-crosslinked by γ-ray irradiation of the corresponding grafted film possessed the highest chemical stability among the prepared membranes, a significantly lower methanol permeability compared to Nafion ® membranes, and a better DMFC performance for high methanol feed concentration. Therefore, this doubly crosslinked membrane was promising for application in a DMFC where relatively high methanol concentration could be fed.

  6. Poly(ether-ether-ketone) orthopedic bearing surface modified by self-initiated surface grafting of poly(2-methacryloyloxyethyl phosphorylcholine).

    PubMed

    Kyomoto, Masayuki; Moro, Toru; Yamane, Shihori; Hashimoto, Masami; Takatori, Yoshio; Ishihara, Kazuhiko

    2013-10-01

    We investigated the production of free radicals on a poly(ether-ether-ketone) (PEEK) substrate under ultraviolet (UV) irradiation. The amount of the ketyl radicals produced from the benzophenone (BP) units in the PEEK molecular structure initially increased rapidly and then became almost constant. Our observations revealed that the BP units in PEEK acted as photoinitiators, and that it was possible to use them to control the graft polymerization of poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC). This "self-initiated surface graft polymerization" method is very convenient in the absence of external photoinitiator. We also investigated the effects of the monomer concentration and UV irradiation time on the extent of the grafted PMPC layer. Furthermore, as an application to improving the durability of artificial hips, we demonstrated the nanometer-scale photoinduced grafting of PMPC onto PEEK and carbon fiber-reinforced PEEK (CFR-PEEK) orthopedic bearing surfaces and interfaces. A variety of test revealed significant improvements in the water wettability, frictional properties, and wear resistance of the surfaces and interfaces.

  7. Swelling properties of cassava starch grafted with poly (potassium acrylate-co-acrylamide) superabsorbent hydrogel prepared by ionizing radiation

    SciTech Connect

    Barleany, Dhena Ria Ulfiyani, Fida; Istiqomah, Shafina; Rahmayetty; Heriyanto, Heri; Erizal

    2015-12-29

    Natural and synthetic hydrophylic polymers can be phisically or chemically cross-linked in order to produce hydrogels. Starch based hydrogels grafted with copolymers from acrylic acid or acrylamide have become very popular for water absorbent application. Superabsorbent hydrogels made from Cassava starch grafted with poly (potassium acrylate-co-acrylamide) were prepared by using of ϒ-irradiation method. Various important parameters such as irradiation doses, monomer to Cassava starch ratio and acrylamide content were investigated. The addition of 7,5 % w w{sup −1} acrylamide into the reaction mixture generated a starch graft copolymer with a water absorption in distilled water as high as 460 g g{sup −1} of its dried weight. The effectivity of hydrogel as superabsorbent for aqueous solutions of NaCl and urea was evaluated. The obtained hydrogel showed the maximum absorptions of 317 g g{sup −1} and 523 g g{sup −1} for NaCl and urea solution, respectively (relative to its own dry weight). The structure of the graft copolymer was analyzed by using Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscope (SEM)

  8. Swelling properties of cassava starch grafted with poly (potassium acrylate-co-acrylamide) superabsorbent hydrogel prepared by ionizing radiation

    NASA Astrophysics Data System (ADS)

    Barleany, Dhena Ria; Ulfiyani, Fida; Istiqomah, Shafina; Heriyanto, Heri; Rahmayetty, Erizal

    2015-12-01

    Natural and synthetic hydrophylic polymers can be phisically or chemically cross-linked in order to produce hydrogels. Starch based hydrogels grafted with copolymers from acrylic acid or acrylamide have become very popular for water absorbent application. Superabsorbent hydrogels made from Cassava starch grafted with poly (potassium acrylate-co-acrylamide) were prepared by using of ϒ-irradiation method. Various important parameters such as irradiation doses, monomer to Cassava starch ratio and acrylamide content were investigated. The addition of 7,5 % w w-1 acrylamide into the reaction mixture generated a starch graft copolymer with a water absorption in distilled water as high as 460 g g-1 of its dried weight. The effectivity of hydrogel as superabsorbent for aqueous solutions of NaCl and urea was evaluated. The obtained hydrogel showed the maximum absorptions of 317 g g-1 and 523 g g-1 for NaCl and urea solution, respectively (relative to its own dry weight). The structure of the graft copolymer was analyzed by using Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscope (SEM).

  9. Prosthetic Arteriovenous Graft Contact Dermatitis Masquerading as an Arteriovenous Graft Infection in a Hemodialysis Patient

    PubMed Central

    Ramagiri-Vinod, Nagadarshini; Tahir, Hassan; Narukonda, Sandhya; Joshi, Medha

    2016-01-01

    Prosthetic arteriovenous (AV) graft is the second most common vascular access of choice in hemodialysis patients. Rare complications of such grafts are increasingly seen due to rising population of patients on hemodialysis. Infections and thrombosis are the most common complications. Though metallic implants are known to cause hypersensitivity skin reactions, prosthetic AV grafts are rarely known to cause such kind of reactions due to inert nature of materials used in their preparation. We present a case of 54-year-old male who developed contact dermatitis after AV graft creation which was mistreated initially as infection. PMID:27493977

  10. Fludarabine Allows Dose Reduction for Total Body Irradiation in Pediatric Hematopoietic Stem Cell Transplantation

    SciTech Connect

    Kornguth, David G. . E-mail: dkorngut@mdanderson.org; Mahajan, Anita; Woo, Shiao; Chan, Ka Wah; Antolak, John; Ha, Chul S.

    2007-07-15

    Purpose: To examine, in the setting of total body irradiation (TBI) for the preparation of pediatric hematopoietic stem cell transplantation (HSCT), whether TBI dose can be reduced without compromising the efficacy of a regimen consisting of fludarabine and radiotherapy; and whether there is any increased risk of pulmonary toxicity due to the radiosensitizing effect of fludarabine. Methods and Materials: A total of 52 pediatric patients with hematologic malignancies received TBI-based conditioning regimens in preparation for allogeneic HSCT. Twenty-three patients received 12 Gy in 4 daily fractions in combination with cyclophosphamide, either alone or with other chemotherapeutic and biologic agents. Twenty-nine patients received 9 Gy in 3 fractions in conjunction with fludarabine and melphalan. Clinical and radiation records were reviewed to determine engraftment, pulmonary toxicity (according to Radiation Therapy Oncology Group criteria), transplant-related mortality, recurrence of primary disease, and overall survival. Results: The two groups of patients had comparable pretransplant clinical characteristics. For the 12-Gy and 9-Gy regimens, the engraftment (89% and 93%; p = 0.82), freedom from life-threatening pulmonary events (65% and 79%; p = 0.33), freedom from relapse (60% and 73%; p = 0.24), and overall survival (26% and 47%; p = 0.09) were not statistically different. Conclusions: The addition of fludarabine and melphalan seems to allow the dose of TBI to be lowered to 9 Gy without loss of engraftment or antitumor efficacy.

  11. Anterior cervical discectomy: to graft or not to graft?

    PubMed

    Konduru, S; Findlay, G

    2009-02-01

    The debate regarding whether to perform an interbody fusion after anterior cervical discectomy (ACD) has been going on for the last 50 years. Several prospective randomized clinical trials have been performed to evaluate the clinical outcome following anterior cervical discectomy with and without interbody fusion. None of these studies show a significant difference between the two techniques in terms of relief of arm pain or neck pain. The operative time, in-hospital stay and time for return to work seem to be slightly longer following anterior cervical discectomy with interbody grafting (ACDF) compared to ACD alone. However a temporary increase in postoperative axial pain seems to be a common complication following ACD. There is also no difference in the clinical outcomes between ACD and ACDF with plating and ACDF with interbody spacers. However, if a fusion procedure is undertaken, the use of interbody spacers does have the advantage of avoiding donor site complications. There is also some evidence to suggest that plate fixation can lead to increased fusion rates. There is a significant risk of a degree of segmental kyphosis following ACD. These radiological features, however, do not correlate with the clinical outcome. Radiological and clinical studies fail to show a significant difference in recurrence of foraminal narrowing or the rates of reoperation following ACD or ACDF. The available body of evidence suggests that the addition of a fusion procedure following anterior cervical decompression may give improved radiological results but does not necessarily result in improved clinical outcomes.

  12. Carboxylated nanodiamonds inhibit γ-irradiation damage of human red blood cells

    NASA Astrophysics Data System (ADS)

    Santacruz-Gomez, K.; Silva-Campa, E.; Melendrez-Amavizca, R.; Teran Arce, F.; Mata-Haro, V.; Landon, P. B.; Zhang, C.; Pedroza-Montero, M.; Lal, R.

    2016-03-01

    Nanodiamonds when carboxylated (cNDs) act as reducing agents and hence could limit oxidative damage in biological systems. Gamma (γ)-irradiation of whole blood or its components is required in immunocompetent patients to prevent transfusion-associated graft versus host disease (TA-GVHD). However, γ-irradiation of blood also deoxygenates red blood cells (RBCs) and induces oxidative damage, including abnormalities in cellular membranes and hemolysis. Using atomic force microscopy (AFM) and Raman spectroscopy, we examined the effect of cNDs on γ-irradiation mediated deoxygenation and morphological damage of RBCs. γ-Radiation induced several morphological phenotypes, including stomatocytes, codocytes and echinocytes. While stomatocytes and codocytes are reversibly damaged RBCs, echinocytes are irreversibly damaged. AFM images show significantly fewer echinocytes among cND-treated γ-irradiated RBCs. The Raman spectra of γ-irradiated RBCs had more oxygenated hemoglobin patterns when cND-treated, resembling those of normal, non-irradiated RBCs, compared to the non-cND-treated RBCs. cND inhibited hemoglobin deoxygenation and morphological damage, possibly by neutralizing the free radicals generated during γ-irradiation. Thus cNDs have the therapeutic potential to preserve the quality of stored blood following γ-irradiation.Nanodiamonds when carboxylated (cNDs) act as reducing agents and hence could limit oxidative damage in biological systems. Gamma (γ)-irradiation of whole blood or its components is required in immunocompetent patients to prevent transfusion-associated graft versus host disease (TA-GVHD). However, γ-irradiation of blood also deoxygenates red blood cells (RBCs) and induces oxidative damage, including abnormalities in cellular membranes and hemolysis. Using atomic force microscopy (AFM) and Raman spectroscopy, we examined the effect of cNDs on γ-irradiation mediated deoxygenation and morphological damage of RBCs. γ-Radiation induced several

  13. Infected aortoiliofemoral grafts: magnetic resonance imaging.

    PubMed

    Justich, E; Amparo, E G; Hricak, H; Higgins, C B

    1985-01-01

    Three patients with proved infected aortoiliofemoral grafts were examined by magnetic resonance (MR) imaging using a spin echo technique. MR clearly identified the perigraft abscess, the involvement of adjacent structures, and the longitudinal extent of the process in all patients. The MR findings were: Abscesses create a high signal intensity, somewhat less than fat. The perigraft abscess has a great contrast with the signal void of flowing blood in the graft. Inflammatory changes cause an inhomogeneous intermediate signal, slightly more intense than muscle. Both abscesses and edematous areas increase their signal intensity with long repetition rates and long echo delays. Areas of gas appear black. They cannot be distinguished from calcified plaques. Additional information is gained about the graft patency. Although the specificity has to be proved, MR imaging is sensitive in the detection of infected grafts and for defining the longitudinal extent of the perigraft abscess.

  14. Polyethylene glycol-grafted polystyrene particles.

    PubMed

    Meng, Fenghua; Engbers, Gerard H M; Feijen, Jan

    2004-07-01

    Densely pegylated particles that can serve as a model system for artificial cells were prepared by covalently grafting amino polyethylene glycol (PEG, molecular weight 3400 or 5000) onto carboxyl polystyrene particles (PS-COOH) using carbodiimide chemistry. PEG-modified particles (PS-PEG) were characterized by determination of the PEG surface concentration, zeta-potential, size, and morphology. Under optimized grafting conditions, a dense "brush-like" PEG layer was formed. A PEG surface concentration of approximately 60 pmol/cm2, corresponding with an average distance between grafted PEG chains of approximately 17 A can be realized. It was shown that grafting of PEG onto PS-COOH reduced the adsorption of proteins from human plasma (85 vol %) in phosphate-buffered saline up to 90%.

  15. Fluorescent Bioactive Corrole Grafted-Chitosan Films.

    PubMed

    Barata, Joana F B; Pinto, Ricardo J B; Vaz Serra, Vanda I R C; Silvestre, Armando J D; Trindade, Tito; Neves, Maria Graça P M S; Cavaleiro, José A S; Daina, Sara; Sadocco, Patrizia; Freire, Carmen S R

    2016-04-11

    Transparent corrole grafted-chitosan films were prepared by chemical modification of chitosan with a corrole macrocycle, namely, 5,10,15-tris(pentafluorophenyl)corrole (TPFC), followed by solvent casting. The obtained films were characterized in terms of absorption spectra (UV-vis), FLIM (fluorescence lifetime imaging microscopy), structure (FTIR, XPS), thermal stability (TGA), thermomechanical properties (DMA), and antibacterial activity. The results showed that the chemical grafting of chitosan with corrole units did not affect its film-forming ability and that the grafting yield increased with the reaction time. The obtained transparent films presented fluorescence which increases with the amount of grafted corrole units. Additionally, all films showed bacteriostatic effect against S. aureus, as well as good thermomechanical properties and thermal stability. Considering these features, promising applications may be envisaged for these corrole-chitosan films, such as biosensors, bioimaging agents, and bioactive optical devices.

  16. Free Fat Graft for Congenital Hand Differences

    PubMed Central

    Ishigaki, Daisuke; Satake, Hiroshi; Iba, Kousuke

    2012-01-01

    Background Free fat graft has been used for the treatment of congenital hand differences. However, there have been a few reports about the outcome of that treatment. In this study, the outcome of free fat grafts for congenital hand and foot differences was investigated. Methods Fourteen bones with longitudinal epiphyseal bracket, 3 wrists with Madelung deformity, and 5 cases of osseous syndactyly were treated with free fat graft with osteotomy, physiolysis, or separation of osseous syndactyly. Of the fourteen bones with longitudinal epiphyseal bracket, 9 were treated with open wedge osteotomy with free fat graft and 5 with physiolysis and free fat graft. The Madelung deformity was treated with physiolysis with free fat graft. For osseous syndactyly, syndactyly release with free fat graft was performed five times on four hands. Results In the fourteen cases with longitudinal epiphyseal bracket, lateral deviation improved in all except two cases after surgery. The average lateral deviation angle changed from 32.5 degrees before surgery to 15.2 degrees after surgery. The average improvement of the lateral deviation angle was 12.2 degrees in the osteotomy group and 20.6 degrees in the physiolysis group. The mean ratio of improvement of the lateral deviation angle to the lateral deviation angle before surgery was 39.4% in the osteotomy group and 51.2% in the physiolysis group. The Madelung deformity improved after surgery in two cases but there was no improvement in one case. For these conditions, the results were not good enough when surgery was done after age 13 or at age four for severely hypoplastic brachymesophalangy. Of the 5 cases of osseous syndactyly, reunion of the separated bones occurred in one case. The grafted free fat should be deep enough to cover the osteotomy site of the bones to prevent reunion of the separated bones. Conclusions Physiolysis and free fat graft performed during the growth period can correct the deviation due to longitudinal epiphyseal

  17. Pretransplant mobilization with granulocyte colony-stimulating factor improves B-cell reconstitution by lentiviral vector gene therapy in SCID-X1 mice.

    PubMed

    Huston, Marshall W; Riegman, Adriaan R A; Yadak, Rana; van Helsdingen, Yvette; de Boer, Helen; van Til, Niek P; Wagemaker, Gerard

    2014-10-01

    Hematopoietic stem cell (HSC) gene therapy is a demonstrated effective treatment for X-linked severe combined immunodeficiency (SCID-X1), but B-cell reconstitution and function has been deficient in many of the gene therapy treated patients. Cytoreductive preconditioning is known to improve HSC engraftment, but in general it is not considered for SCID-X1 since the poor health of most of these patients at diagnosis and the risk of toxicity preclude the conditioning used in standard bone marrow stem cell transplantation. We hypothesized that mobilization of HSC by granulocyte colony-stimulating factor (G-CSF) should create temporary space in bone marrow niches to improve engraftment and thereby B-cell reconstitution. In the present pilot study supplementing our earlier preclinical evaluation (Huston et al., 2011), Il2rg(-/-) mice pretreated with G-CSF were transplanted with wild-type lineage negative (Lin(-)) cells or Il2rg(-/-) Lin(-) cells transduced with therapeutic IL2RG lentiviral vectors. Mice were monitored for reconstitution of lymphocyte populations, level of donor cell chimerism, and antibody responses as compared to 2 Gy total body irradiation (TBI), previously found effective in promoting B-cell reconstitution. The results demonstrate that G-CSF promotes B-cell reconstitution similar to low-dose TBI and provides proof of principle for an alternative approach to improve efficacy of gene therapy in SCID patients without adverse effects associated with cytoreductive conditioning.

  18. Pretransplant Mobilization with Granulocyte Colony-Stimulating Factor Improves B-Cell Reconstitution by Lentiviral Vector Gene Therapy in SCID-X1 Mice

    PubMed Central

    Huston, Marshall W.; Riegman, Adriaan R.A.; Yadak, Rana; van Helsdingen, Yvette; de Boer, Helen; van Til, Niek P.

    2014-01-01

    Abstract Hematopoietic stem cell (HSC) gene therapy is a demonstrated effective treatment for X-linked severe combined immunodeficiency (SCID-X1), but B-cell reconstitution and function has been deficient in many of the gene therapy treated patients. Cytoreductive preconditioning is known to improve HSC engraftment, but in general it is not considered for SCID-X1 since the poor health of most of these patients at diagnosis and the risk of toxicity preclude the conditioning used in standard bone marrow stem cell transplantation. We hypothesized that mobilization of HSC by granulocyte colony-stimulating factor (G-CSF) should create temporary space in bone marrow niches to improve engraftment and thereby B-cell reconstitution. In the present pilot study supplementing our earlier preclinical evaluation (Huston et al., 2011), Il2rg−/− mice pretreated with G-CSF were transplanted with wild-type lineage negative (Lin−) cells or Il2rg−/− Lin− cells transduced with therapeutic IL2RG lentiviral vectors. Mice were monitored for reconstitution of lymphocyte populations, level of donor cell chimerism, and antibody responses as compared to 2 Gy total body irradiation (TBI), previously found effective in promoting B-cell reconstitution. The results demonstrate that G-CSF promotes B-cell reconstitution similar to low-dose TBI and provides proof of principle for an alternative approach to improve efficacy of gene therapy in SCID patients without adverse effects associated with cytoreductive conditioning. PMID:25222508

  19. Non-Anastomotic Rupture of a Woven Dacron Graft in the Descending Thoracic Aorta Treated with Endovascular Stent Grafting.

    PubMed

    Lee, Youngok; Kim, Gun-Jik; Kim, Young Eun; Hong, Seong Wook; Lee, Jong Tae

    2016-12-01

    The intrinsic structural failure of a Dacron graft resulting from the loss of structural integrity of the graft fabric can cause late graft complications. Late non-anastomotic rupture has traditionally been treated surgically via open thoracotomy. We report a case of the successful use of thoracic endovascular repair to treat a Dacron graft rupture in the descending aorta. The rupture occurred 20 years after the graft had been placed. Two stent grafts were placed at the proximal portion of the surgical graft, covering almost its entire length.

  20. Abrogation of hybrid resistance to bone marrow engraftment by graft versus host induced immune deficiency

    SciTech Connect

    Hakim, F.T.; Shearer, G.M.

    1986-03-01

    Lethally irradiated F/sub 1/ mice, heterozygous at the hematopoietic histocompatibility (Hh) locus at H-2D/sup b/, reject bone marrow grafts from homozygous H-2/sup b/ parents. This hybrid resistance (HR) is reduced by prior injection of H-2/sup b/ parental spleen cells. Since injection of parental spleen cells produces a profound suppression of F/sub 1/ immune functions, the authors investigated whether parental-induced abrogation of HR was due to graft-vs-host induced immune deficiency (GVHID). HR was assessed by quantifying engraftment in irradiated mice using /sup 125/I-IUdR spleen uptake; GVHID by measuring generation of cytotoxic T lymphocytes (CTL) from unirradiated mice. They observed correlation in time course, spleen dose dependence and T cell dependence between GVHID and loss of HR. The injection of B10 recombinant congenic spleens into (B10 x B10.A) F/sub 1/ mice, prior to grafting with B10 marrow, demonstrated that only those disparities in major histocompatibility antigens which generated GVHID would result in loss of HR. Spleens from (B10 x B10.A(2R))F/sub 1/ mice (Class I disparity only) did not induce GVHID or affect HR, while (B10 x B10.A(5R)F/sub 1/ spleens (Class I and II disparity) abrogated CTL generation and HR completely. GVHID produced by a Class II only disparity, as in (B10 x B10.A(5R))F/sub 1/ spleens injected into (B6/sup bm12 x B10.A(5R))F/sub 1/ mice, was also sufficient to markedly reduce HR to B10 bone marrow. Modulation of hematopoietic graft rejection by GVHID may affect marrow engraftment in man.

  1. DNA nanosensor surface grafting and salt dependence

    NASA Astrophysics Data System (ADS)

    Carvalho, B. G.; Fagundes, J.; Martin, A. A.; Raniero, L.; Favero, P. P.

    2013-02-01

    In this paper we investigated the Paracoccidoides brasiliensis fungus nanosensor by simulations of simple strand DNA grafting on gold nanoparticle. In order to improve the knowledge of nanoparticle environment, the addiction of salt solution was studied at the models proposed by us. Nanoparticle and DNA are represented by economic models validated by us in this paper. In addition, the DNA grafting and salt influences are evaluated by adsorption and bond energies calculations. This theoretical evaluation gives support to experimental diagnostics techniques of diseases.

  2. Biomaterials in Maxillofacial Surgery: Membranes and Grafts

    PubMed Central

    Rodella, Luigi F.; Favero, Gaia; Labanca, Mauro

    2011-01-01

    Today, significant differences in the use of biomaterials (membranes and grafts) of animal or synthetic origin have yet to be reported. Nevertheless, some evidences suggest that synthetic materials have a lower risk of disease transmission. This review aims to assess the available informations on regenerative bone technique using reasorbable membranes and bone grafts. In particular, biocompatibility, immunological response, tissue reaction, reabsorption time and histological features of materials daily use in dentistry and in maxillofacial surgery were emphasized. PMID:23675225

  3. Biomaterials in maxillofacial surgery: membranes and grafts.

    PubMed

    Rodella, Luigi F; Favero, Gaia; Labanca, Mauro

    2011-06-01

    Today, significant differences in the use of biomaterials (membranes and grafts) of animal or synthetic origin have yet to be reported. Nevertheless, some evidences suggest that synthetic materials have a lower risk of disease transmission. This review aims to assess the available informations on regenerative bone technique using reasorbable membranes and bone grafts. In particular, biocompatibility, immunological response, tissue reaction, reabsorption time and histological features of materials daily use in dentistry and in maxillofacial surgery were emphasized.

  4. Increased bacterial infections after transfusion of leukoreduced non-irradiated blood products in recipients of allogeneic stem cell transplants after reduced-intensity conditioning.

    PubMed

    Jaime-Pérez, José C; Villarreal-Villarreal, César D; Salazar-Riojas, Rosario; Méndez-Ramírez, Nereida; Vázquez-Garza, Eduardo; Gómez-Almaguer, David

    2015-03-01

    Blood components transfused to hematopoietic stem cell transplant (HSCT) recipients are irradiated to prevent transfusion-associated graft-versus-host disease (TA-GVHD). The effect of transfusing non-irradiated blood products in HSCT outcome, including incidence of transplant complications, bacterial infections, acute and chronic GVHD presentation, and characteristics, has not been documented. Clinical records as well as blood bank and electronic databases of HSCT patients grafted after reduced-intensity conditioning who received irradiated versus non-irradiated blood products, after blood irradiation became unavailable at our center, were scrutinized for transplant outcome, clinical evolution, engraftment characteristics including days to neutrophil and platelet recovery, acute and chronic GVHD, rate and type of infections, and additional transplant-related comorbidities. All transfused blood products were leukoreduced. A total of 156 HSCT recipients was studied, 73 received irradiated and 83 non-irradiated blood components. Bacterial infections were significantly more frequent in patients transfused with non-irradiated blood products, P = .04. Clinically relevant increased rates of fever and neutropenia and mucositis were also documented in these patients. No cases of TA-GVHD occurred. Classical GVHD developed in 37 patients (50.7%) who received irradiated blood products and 36 (43.9%) who received non-irradiated blood products, P = .42. Acute GVHD developed in 28 patients (38.4%) in the blood-irradiated and 33 patients (39.8%) in the non-irradiation group, P = .87. The 2-year GVHD-free survival rate was 40% in the irradiated versus 40.6% in the non-irradiation group, P = .071. Increased bacterial infections were found in HSCT recipients transfused with non-irradiated blood products, which ideally must always be irradiated.

  5. Oversized vein grafts develop advanced atherosclerosis in hypercholesterolemic minipigs

    PubMed Central

    2012-01-01

    Background Accelerated atherosclerosis is the main cause of late aortocoronary vein graft failure. We aimed to develop a large animal model for the study of pathogenesis and treatment of vein graft atherosclerosis. Methods An autologous reversed jugular vein graft was inserted end-to-end into the transected common carotid artery of ten hypercholesteroemic minipigs. The vein grafts were investigated 12-14 weeks later with ultrasound and angiograpy in vivo and microscopy post mortem. Results One minipig died during follow up (patent vein graft at autopsy), and one vein graft thrombosed early. In the remaining eight patent vein grafts, the mean (standard deviation) intima-media thickness was 712 μm (276 μm) versus 204 μm (74 μm) in the contralateral control internal jugular veins (P < .01). Advanced atherosclerotic plaques were found in three of four oversized vein grafts (diameter of graft > diameter of artery). No plaques were found in four non-oversized vein grafts (P < .05). Conclusions Our model of jugular vein graft in the common carotid artery of hypercholesterolemic minipigs displayed the components of human vein graft disease, i.e. thrombosis, intimal hyperplasia, and atherosclerosis. Advanced atherosclerosis, the main cause of late failure of human aortocoronary vein grafts was only seen in oversized grafts. This finding suggests that oversized vein grafts may have detrimental effects on patient outcome. PMID:22463679

  6. Polypeptide Grafted Hyaluronan: Synthesis and Characterization

    SciTech Connect

    Wang, Xiaojun; Messman, Jamie M; Mays, Jimmy; Baskaran, Durairaj

    2010-01-01

    Poly(L-leucine) grafted hyaluronan (HA-g-PLeu) has been synthesized via a Michael addition reaction between primary amine terminated poly(L-leucine) and acrylate-functionalized HA (TBAHA-acrylate). The precursor hyaluronan was first functionalized with acrylate groups by reaction with acryloyl chloride in the presence of triethylamine in N,N-dimethylformamide. 1H NMR analysis of the resulting product indicated that an increase in the concentration of acryloylchoride with respect to hydroxyl groups on HA has only a moderate effect on functionalization efficiency, f. A precise control of stoichiometry was not achieved, which could be attributed to partial solubility of intermolecular aggregates and the hygroscopic nature of HA. Michael addition at high [PLeu- NH2]/[acrylate]TBAHA ratios gave a molar grafting ratio of only 0.20 with respect to the repeat unit of HA, indicating grafting limitation due to insolubility of the grafted HA-g-PLeu. Soluble HA-g-PLeu graft copolymers were obtained for low grafting ratios (<0.039) with <8.6% by mass of PLeu and were characterized thoroughly using light scattering, 1H NMR, FT-IR, and AFM techniques. Light scattering experiments showed a strong hydrophobic interaction between PLeu chains, resulting in aggregates with segregated nongrafted HA segments. This yields local networks of aggregates, as demonstrated by atomic force microscopy. Circular dichroism spectroscopy showed a -sheet conformation for aggregates of poly(L-leucine).

  7. Photoacoustic detection of neovascularities in skin graft

    NASA Astrophysics Data System (ADS)

    Yamazaki, Mutsuo; Sato, Shunichi; Saitoh, Daizo; Ishihara, Miya; Okada, Yoshiaki; Ashida, Hiroshi; Obara, Minoru

    2005-04-01

    We previously proposed a new method for monitoring adhesion of skin graft by measuring photoacoustic (PA) signal originated from the neovascularities. In this study, immunohistochemical staining (IHC) with CD31 antibody was performed for grafted skin tissue to observe neovascularity, and the results were compared with PA signals. We also used a laser Doppler imaging (LDI) to observe blood flow in the grafted skin, and sensitivity of PA measurement and that of LDI were compared. In rat autograft models, PA signals were measured for the grafted skin at postgrafting times of 0-48 h. At 6 h postgrafting, PA signal was observed in the skin depth region of 500-600 mm, while the results of IHC showed that angiogenesis occurred at the depth of about 600 mm. Depths at which PA signal and angiogenesis were observed decreased with postgrafting time. These indicate that the PA signal observed at 6 h postgrafting originated from the neovascularities in the skin graft. Results of LDI showed no blood-originated signal before 48 h postgrafting. These findings suggest that PA measurement is effective in monitoring the adhesion of skin graft in early stage after transplantation.

  8. Neointimal hyperplasia associated with synthetic hemodialysis grafts

    PubMed Central

    Li, Li; Terry, Christi M.; Shiu, Yan-Ting E.; Cheung, Alfred K.

    2008-01-01

    Stenosis is a major cause of failure of hemodialysis vascular grafts and is primarily caused by neointimal hyperplasia (NH) at the anastomoses. The objective of this article is to provide a scientific review of the biology underlying this disorder and a critical review of the state-of-the-art investigational preventive strategies in order to stimulate further research in this exciting area. The histology of the NH shows myofibroblasts (that are probably derived from adventitial fibroblasts), extracellular matrices, pro-inflammatory cells including foreign-body giant cells, a variety of growth factors and cytokines, and neovasculature. The contributing factors of the pathogenesis of NH include surgical trauma, bioincompatibility of the synthetic graft, and the various mechanical stresses that result from luminal hypertension and compliance mismatch between the vessel wall and graft. These mechanical stimuli are focal in nature and may have a significant influence on the preferential localization of the NH. Novel mechanical graft designs and local drug delivery strategies show promise in animal models in preventing graft NH development. Successful prevention of graft stenosis would provide a superior alternative to the native fistula as hemodialysis vascular access. PMID:18668026

  9. Effects of storage on irradiated red blood cells: An in-vitro and in-vivo study. Master's thesis

    SciTech Connect

    Knoll, S.E.

    1991-08-01

    Irradiation of red blood cell units has recently become a topic of special concern as the result of increasing reports of graft versus host disease in immunocompetent blood transfusion recipients. This study was designed to evaluate the potassium elevations observed in stored irradiated red blood cells and to evaluate the in vivo survival of stored irradiated red blood cells using a dog model. In the in vitro study ten units of human CPDA-1 packed red blood cells were made into paired aliquots; one aliquot of each pair was irradiated with 3000 rads of gamma radiation and the potassium content measured at points throughout 35 days of storage. A significant increase in potassium levels in the irradiated aliquots was observed from the first day after irradiation and continued through the entire storage period.

  10. Water swelling properties of the electron beam irradiated PVA-g-AAc hydrogels

    NASA Astrophysics Data System (ADS)

    Wang, Qingguo; Zhou, Xue; Zeng, Jinxia; Wang, Jizeng

    2016-02-01

    In this paper, the electron beam irradiation technology being more suitable for the industry application is explored to fabricate the acrylic acid (AAc) monomer-grafted polyvinyl alcohol (PVA-g-AAc) hydrogels. ATR-IR spectra of the PVA-g-AAc hydrogels shows an obvious absorption peak of the sbnd Cdbnd O group at 1701 cm-1, indicating that the AAc monomers were grafted onto the PVA macromolecules. This paper also studied some effects of the mass ratio of PVA/AAc, pH of buffer solution and irradiation dosage on the water swelling properties of the electron beam irradiated PVA-g-AAc hydrogels. The water swelling ratio of PVA-g-AAc hydrogels decreases with increased irradiation dosage and mass ratio of PVA/AAc, whereas swelling ratio increases with increased pH of buffer solution and soaking time. The water-swelling behavior of PVA-g-AAc hydrogels occurred easily in an alkaline environment, particularly in a buffer solution with pH 9.2. Both PVA-g-AAc hydrogels (PVA/AAc = 1/5, w/w) irradiated with 5 kilogray (kGy) and PVA-g-AAc hydrogels (PVA/AAc = 1/1, w/w) irradiated with 15 kGy could easily absorb water and lead to high water swelling ratios (up to about 600%), which are potential candidates to meet the requirements for some biomedical applications.

  11. Radiation-induced graft copolymerization of poly(ethylene glycol) monomethacrylate onto deoxycholate-chitosan nanoparticles as a drug carrier

    NASA Astrophysics Data System (ADS)

    Pasanphan, Wanvimol; Rattanawongwiboon, Thitirat; Rimdusit, Pakjira; Piroonpan, Thananchai

    2014-01-01

    Poly(ethylene glycol) monomethacrylate-grafted-deoxycholate chitosan nanoparticles (PEGMA-g-DCCSNPs) were successfully prepared by radiation-induced graft copolymerization. The hydrophilic poly(ethylene glycol) monomethacrylate was grafted onto deoxycholate-chitosan in an aqueous system. The radiation-absorbed dose is an important parameter on degree of grafting, shell thickness and particle size of PEGMA-g-DCCSNPs. Owing to their amphiphilic architecture, PEGMA-g-DCCSNPs self-assembled into spherical core-shell nanoparticles in aqueous media. The particle size of PEGMA-g-DCCSNPs measured by TEM varied in the range of 70-130 nm depending on the degree of grafting as well as the irradiation dose. Berberine (BBR) as a model drug was encapsulated into the PEGMA-g-DCCSNPs. Drug release study revealed that the BBR drug was slowly released from PEGMA-g-DCCSNPs at a mostly constant rate of 10-20% in PBS buffer (pH 7.4) at 37 °C over a period of 23 days.

  12. Radiation-grafting of 2-hydroxyethylmethacrylate and oligo (ethylene glycol) methyl ether methacrylate onto polypropylene films by one step method

    NASA Astrophysics Data System (ADS)

    Ramírez-Jiménez, Alejandro; Alvarez-Lorenzo, Carmen; Concheiro, Angel; Bucio, Emilio

    2012-01-01

    Polypropylene films were modified with 2-hydroxyethylmethacrylate (HEMA) and oligo (ethylene glycol) methyl ether methacrylate (OEGMA) using the pre-irradiation method with gamma-rays (one step method). The effect of absorbed dose from 10 to 100 kGy, temperature (50, 60, and 70 °C), monomer concentration between 12.5% and 62.5%, monomers ratio from 10% to 90% and reaction time from 5 to 50 h; on the degree of grafting was determined. The grafted samples were analyzed by FTIR-ATR, TGA, DSC, swelling, and contact angle. Grafts onto polymeric films between 3% and 109% were obtained at doses from 10 to 100 kGy and a dose rate around 7.4 kGy/h. The graft percent increased with the content in HEMA in the HEMA:OEGMA feed mixture, which indicates a lower reactivity of OEGMA compared to HEMA. The hydrogel layer grafted on the polypropylene substrate increases the hydrophilicity of the surface and also provides certain temperature-responsiveness, which may be of interest for biomedical applications.

  13. Effects of thymus irradiation on the immune competence of T cells after total-lymphoid irradiation

    SciTech Connect

    Palathumpat, V.C.; Vandeputte, M.M.; Waer, M. )

    1990-07-01

    Spleen cells from mice receiving TLI, with or without thymus shielding, were investigated for in vitro and in vivo defects. At 4-6 weeks after irradiation spleen cells of both groups showed a normal number of Thy1 (T cells), L3T4 (CD4 positive T cells) cells, and an absence of natural suppressor cells. Splenocytes of the nonthymic shielded TLI group were not able to mount either a normal in vitro response (in MLR or PHA) or an in vivo graft-versus-host-disease reaction when injected into lethally irradiated adult allogeneic recipients or into neonatal F1 hybrids. This was in contrast to the normal immune capacity of spleen cells from the thymus shielded group that gave normal MLR and PHA tests in vitro and provoked GVHD in vivo. Thymuses recovered from mice receiving TLI with or without thymic shielding were however equally efficient in restoring the immune capacity after transplantation into neonatally thymectomized mice as measured by the PHA assay. Thymic irradiation is therefore necessary but not sufficient for creating long-lasting immune defects after TLI.

  14. Alaskan Commodities Irradiation Project

    SciTech Connect

    Zarling, J.P.; Swanson, R.B.; Logan, R.R.; Das, D.K.; Lewis, C.E.; Workman, W.G.; Tumeo, M.A.; Hok, C.I.; Birklid, C.A.; Bennett, F.L.

    1988-12-01

    The ninety-ninth US Congress commissioned a six-state food irradiation research and development program to evaluate the commercial potential of this technology. Hawaii, Washington, Iowa, Oklahoma and Florida as well as Alaska have participated in the national program; various food products including fishery products, red meats, tropical and citrus fruits and vegetables have been studied. The purpose of the Alaskan study was to review and evaluate those factors related to the technical and economic feasibility of an irradiator in Alaska. This options analysis study will serve as a basis for determining the state's further involvement in the development of food irradiation technology. 40 refs., 50 figs., 53 tabs.

  15. Prolongation of rat heart allografts by donor-specific blood transfusion treated with ultraviolet irradiation

    SciTech Connect

    Oluwole, S.F.; Iga, C.; Lau, H.; Hardy, M.A.

    1985-07-01

    The effect of donor-specific blood transfusion was compared to that of UVB-irradiated donor-specific blood transfusion on heart allograft survival in inbred rats with major histocompatibility differences. In one series ACI rats received heterotopic heart grafts from Lewis rats and 1 mL transfusion of donor-type blood at 1, 2, and 3 weeks prior to the transplantation. Fifty percent of the grafts were permanently accepted (survival greater than 200 days). Following UVB-irradiated donor-specific blood transfusion, 55% of the grafts survived indefinitely. In a mixed lymphocyte reaction ACI lymphocytes are weak responders to Lewis lymphocytes. In another series, Lewis rats received ACI hearts. Donor-specific transfusions at 1, 2, and 3 weeks prior to transplantation did not significantly alter the survival of heart allografts. Lewis lymphocytes react strongly to ACI stimulator cells in a mixed lymphocyte reaction. However, when the donor blood was UVB-irradiated prior to transfusion, the ACI allograft survival was significantly prolonged in this ACI-to-Lewis strain combination. When Lewis rats received W/F hearts following either donor-specific or UVB-irradiated donor-specific transfusions, the hearts' survival was similarly and significantly prolonged, but did not become permanent. Mixed lymphocyte reaction reveals that the stimulation index of Lewis lymphocytes against W/F lymphocytes is greater than that of ACI versus Lewis, but is less than that between Lewis responder cells against ACI stimulators.

  16. Bone-Grafting in Polyostotic Fibrous Dysplasia

    PubMed Central

    Leet, Arabella I.; Boyce, Alison M.; Ibrahim, Khalda A.; Wientroub, Shlomo; Kushner, Harvey; Collins, Michael T.

    2016-01-01

    Background: Polyostotic fibrous dysplasia is a skeletal disease that results from somatic activating mutations in the gene GNAS in skeletal stem cells, leading to proliferation of immature osteogenic cells with replacement of normal marrow and bone with fibro-osseous tissue. Lesions may cause bone deformity or fracture. In the surgical care of polyostotic fibrous dysplasia, the role of grafting and the optimal grafting material are not clear. The purpose of this study was to evaluate the long-term survival of bone-grafting procedures in subjects with polyostotic fibrous dysplasia over time. Methods: The operative reports and radiographs of a cohort of subjects with polyostotic fibrous dysplasia followed in a natural history study were reviewed. Twenty-three subjects (mean age at the time of enrollment, thirteen years [range, two to forty years]) with fifty-two bone-grafting procedures had a mean follow-up time of 19.6 years (range, twenty-nine months to forty-seven years). Kaplan-Meier life table estimates, Cox proportional hazard models, and t tests comparing means were performed to assess various aspects of graft survival. Results: Kaplan-Meier curves showed a 50% estimate of survival of 14.5 years. Cox proportional hazards models showed no advantage comparing allograft with autograft or structural with nonstructural graft materials. The mean age of the patients was significantly greater (p < 0.001) in the subgroup of subjects in whom grafts were maintained over time (20.9 years) compared with the subgroup of patients whose grafts were resorbed over time (9.8 years). Conclusions: Bone-grafting, including both allograft and autograft, is of limited value in ablating the lesions of fibrous dysplasia. The expectations of patients and surgeons should include the high probability of graft resorption over time with return of bone characteristics of fibrous dysplasia, particularly in younger patients. This suggests the maintenance of normal bone mechanics with implant

  17. Outcomes of acute leukemia patients transplanted with naive T cell–depleted stem cell grafts

    PubMed Central

    Bleakley, Marie; Heimfeld, Shelly; Loeb, Keith R.; Jones, Lori A.; Chaney, Colette; Seropian, Stuart; Gooley, Ted A.; Sommermeyer, Franziska; Riddell, Stanley R.; Shlomchik, Warren D.

    2015-01-01

    BACKGROUND. Graft-versus-host disease (GVHD) is a major cause of morbidity and mortality following allogeneic hematopoietic stem cell transplantation (HCT). In mice, naive T cells (TN) cause more severe GVHD than memory T cells (TM). We hypothesized that selective depletion of TN from human allogeneic peripheral blood stem cell (PBSC) grafts would reduce GVHD and provide sufficient numbers of hematopoietic stem cells and TM to permit hematopoietic engraftment and the transfer of pathogen-specific T cells from donor to recipient, respectively. METHODS. In a single-arm clinical trial, we transplanted 35 patients with high-risk leukemia with TN-depleted PBSC grafts following conditioning with total body irradiation, thiotepa, and fludarabine. GVHD prophylactic management was with tacrolimus immunosuppression alone. Subjects received CD34-selected PBSCs and a defined dose of TM purged of CD45RA+ TN. Primary and secondary objectives included engraftment, acute and chronic GVHD, and immune reconstitution. RESULTS. All recipients of TN-depleted PBSCs engrafted. The incidence of acute GVHD was not reduced; however, GVHD in these patients was universally corticosteroid responsive. Chronic GVHD was remarkably infrequent (9%; median follow-up 932 days) compared with historical rates of approximately 50% with T cell–replete grafts. TM in the graft resulted in rapid T cell recovery and transfer of protective virus-specific immunity. Excessive rates of infection or relapse did not occur and overall survival was 78% at 2 years. CONCLUSION. Depletion of TN from stem cell allografts reduces the incidence of chronic GVHD, while preserving the transfer of functional T cell memory. TRIAL REGISTRATION. ClinicalTrials.gov (NCT 00914940). FUNDING. NIH, Burroughs Wellcome Fund, Leukemia and Lymphoma Society, Damon Runyon Cancer Research Foundation, and Richard Lumsden Foundation. PMID:26053664

  18. Grafting onto poly(ethylene terephthalate) driven by 172 nm UV light

    NASA Astrophysics Data System (ADS)

    Zhu, Zhengmao; Kelley, Michael J.

    2005-10-01

    The reactivity of the surface of poly(ethylene terephthalate) (PET) film under 172 nm UV irradiation (xenon excimer lamp) towards nitrogen-borne 1-octene, n-nonane and heptafluorodecene vapor was investigated. Materials receiving from 0 to 24 J/cm 2 of UV were examined by X-ray photoelectron spectroscopy (XPS), time of flight secondary ion mass spectroscopy (ToF/SIMS), water and mineral oil contact angle measurement and atomic force microscopy (AFM). A uniform nanoscale layer developed on PET surface attributed to the grafting reaction between photolytically-produced polymer radicals and vapor phase molecules.

  19. Analysis of Fibular Single Graft and Fibular Double-barrel Graft for Mandibular Reconstruction

    PubMed Central

    Shimizu, Yusuke; Ihara, Jyun; Kishi, Kazuo

    2016-01-01

    Background: High-quality mandibular reconstruction using vascularized free fibular graft is necessary to provide an osseointegrated dental implant and fixed denture. An appropriate crown–implant ratio is needed, and a good match between bones is extremely important. There are no articles describing the analysis and evaluation of both the fibula and mandible in the same patients. Methods: Computed tomography images of both mandible and fibula of 80 patients were selected in a random manner. We measured bone height of the fibula and mandible at specified points and evaluated the difference of bone height between the fibula and mandible using fibular single or double-barrel grafts. Results: The percentage of patients who had a “good” result for a fibular single graft was only 13.8%. There was no significant difference in bone heights when analyzed by gender. Whether patients were dentulous or not had a large influence on the difference between fibular and mandibular bone heights. Most young patients, but only half of older patients, needed fibular double-barrel grafts. Overweight patients with a high body mass index more often needed fibular double-barrel grafts. Conclusions: For mandibular reconstruction using a fibular graft, preoperative analysis of the patient’s profile and proper use of a fibular single or double-barrel graft contribute to minimizing the difference between the height of the grafted fibula and native mandible and are keys to an ideal reconstruction with good cosmetics and function. PMID:27622091

  20. Treatment of Venous Aortorenal Bypass Graft Aneurysm Using a Stent-Graft

    SciTech Connect

    Novotny, Jiri Peregrin, Jan H.; Stribrna, Jarmila; Janousek, Radim

    2010-02-15

    We present the case of a 77-year-old male patient who had undergone a bilateral venous aortorenal bypass graft 30 years previously. Thirteen years previously, the patient was shown to have a decrease in renal function, with mild shrinking of both kidneys; additionally, a stenosis was found in the left proximal anastomosis. At the most recent follow-up visit (1 year previously), ultrasound revealed an aneurysm (42 mm in diameter) of the left renal bypass graft; the finding was confirmed by CT angiography. A significant ostial stenosis of the left renal bypass graft was also confirmed. It was decided to place a self-expandable stent-graft into the aneurysm while also attempting to dilate the stenosis. Proximal endoleak after stent-graft placement necessitated the implantation of another, balloon-expandable stent-graft into the bypass graft ostium. Postprocedural angiography and follow-up by CT angiography at 3 months confirmed good patency of the stent-grafts and complete thrombosis of the aneurysmal sac, with preserved kidney perfusion. Renal function remained unaltered, while the hypertension is better controlled.

  1. Grafting Seedless Watermelons, How and Why? Will Grafting Help With Disease Control?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In recent years, the practice of grafting seedless watermelons (triploids) onto rootstocks belonging to other Cucurbitaceae genera has gained importance in the United States. Grafting vegetable crops, especially cucurbit’s, is very common in Europe and Asia. In these regions, the practice of crop ...

  2. Physical properties of agave cellulose graft polymethyl methacrylate

    SciTech Connect

    Rosli, Noor Afizah; Ahmad, Ishak; Abdullah, Ibrahim; Anuar, Farah Hannan

    2013-11-27

    The grafting polymerization of methyl methacrylate and Agave cellulose was prepared and their structural analysis and morphology were investigated. The grafting reaction was carried out in an aqueous medium using ceric ammonium nitrate as an initiator. The structural analysis of the graft copolymers was carried out by Fourier transform infrared and X-ray diffraction. The graft copolymers were also characterized by field emission scanning electron microscopy (FESEM). An additional peak at 1732 cm{sup −1} which was attributed to the C=O of ester stretching vibration of poly(methyl methacrylate), appeared in the spectrum of grafted Agave cellulose. A slight decrease of crystallinity index upon grafting was found from 0.74 to 0.68 for cellulose and grafted Agave cellulose, respectively. Another evidence of grafting showed in the FESEM observation, where the surface of the grafted cellulose was found to be roughed than the raw one.

  3. Physical properties of agave cellulose graft polymethyl methacrylate

    NASA Astrophysics Data System (ADS)

    Rosli, Noor Afizah; Ahmad, Ishak; Abdullah, Ibrahim; Anuar, Farah Hannan

    2013-11-01

    The grafting polymerization of methyl methacrylate and Agave cellulose was prepared and their structural analysis and morphology were investigated. The grafting reaction was carried out in an aqueous medium using ceric ammonium nitrate as an initiator. The structural analysis of the graft copolymers was carried out by Fourier transform infrared and X-ray diffraction. The graft copolymers were also characterized by field emission scanning electron microscopy (FESEM). An additional peak at 1732 cm-1 which was attributed to the C=O of ester stretching vibration of poly(methyl methacrylate), appeared in the spectrum of grafted Agave cellulose. A slight decrease of crystallinity index upon grafting was found from 0.74 to 0.68 for cellulose and grafted Agave cellulose, respectively. Another evidence of grafting showed in the FESEM observation, where the surface of the grafted cellulose was found to be roughed than the raw one.

  4. Food irradiation in perspective

    NASA Astrophysics Data System (ADS)

    Henon, Y. M.

    1995-02-01

    Food irradiation already has a long history of hopes and disappointments. Nowhere in the world it plays the role that it should have, including in the much needed prevention of foodborne diseases. Irradiated food sold well wherever consumers were given a chance to buy them. Differences between national regulations do not allow the international trade of irradiated foods. While in many countries food irradiation is still illegal, in most others it is regulated as a food additive and based on the knowledge of the sixties. Until 1980, wholesomeness was the big issue. Then the "prerequisite" became detection methods. Large amounts of money have been spent to design and validate tests which, in fact, aim at enforcing unjustified restrictions on the use of the process. In spite of all the difficulties, it is believed that the efforts of various UN organizations and a growing legitimate demand for food safety should in the end lead to recognition and acceptance.

  5. [The irradiation process].

    PubMed

    Barillot, I; Chauvet, B; Hannoun Lévi, J M; Lisbona, A; Leroy, T; Mahé, M A

    2016-09-01

    The purpose of this article is to describe the regulatory framework of the radiotherapy practice in France, the external irradiation and brachytherapy process and the guidelines for patient follow-up.

  6. Repeat corneal graft failure due to graft-to-host herpetic infection

    PubMed Central

    2013-01-01

    Background Herein, we present the case of a young female patient with keratoconus, who was subjected twice to repeat keratoplasty, and each time, she experienced a corneal graft failure. Findings Under the suspicion of herpetic eye disease, we administered topical and systemic anti-herpetic treatment after the second repeat keratoplasty. The postoperative course was uneventful, and the corneal graft is clear, until recently. Immunohistochemistry and DNA-polymerase chain reaction were negative for herpes simplex virus-1 (HSV-1) in the host cornea, but they detected HSV-1 in both transplanted corneal grafts, thereby supporting our clinical hypothesis that graft-to-host HSV-1 infection elicited this chain reaction of complications in our patient. Conclusion This clinical report illustrates in a unique way the dramatic impact an unsuspected herpetic infection in the corneal graft in cases of keratoplasty may have and underscores the necessity of suspecting and adequately treating these distinct cases. PMID:23514192

  7. Adolescent External Iliac Artery Trauma: Recurrent Aneurysmal Dilatation of an Iliofemoral Saphenous Vein Graft Treated by Stent-Grafting

    SciTech Connect

    Lenton, James; Davies, John; Homer-Vanniasinkam, S.; McPherson, Simon

    2008-09-15

    An adolescent male sustained a severe penetrating injury to the external iliac artery. Emergency surgical revascularization was with a reversed long saphenous vein interposition graft. The primary graft and the subsequent revision graft both became aneurysmal. The second graft aneurysm was successfully excluded by endovascular stent-grafts with medium-term primary patency. A venous graft was used initially rather than a synthetic graft to reduce the risk of infection and the potential problems from future growth. Aneurysmal dilatation of venous grafts in children and adolescents is a rare but recognized complication. To the best of our knowledge, exclusion of these aneurysms with stent-grafts has not been previously reported in the adolescent population.

  8. Onlay Bone Grafts in Head and Neck Reconstruction

    PubMed Central

    Yazar, Sukru

    2010-01-01

    Bone grafts are used in a variety of clinical situations and can be divided into two categories: treatment of bone gaps (inlay bone grafting) and bone projection (onlay bone grafting). Cortical grafts are useful in situations requiring immediate mechanical strength. These grafts can survive with or without complete revascularization or resorption and are primarily used by plastic surgeons in the treatment of bone volume deficiency. Cancellous grafts, in contrast, have no mechanical strength and therefore require additional support to bridge bone defects. Thus, they are used primarily for the treatment of bone gaps and in general revascularize quickly, resorb completely, and stimulate significant new bone formation. PMID:22550447

  9. Aorto-coronary vein graft 'Y' anastomosis made easy.

    PubMed

    Jarvis, Martin Amadee

    2011-10-01

    Vein graft-to-vein graft anastomosis, creating a 'Y' graft, is a useful technique when there is a lack of good-quality autologous vein to perform individual aorto-coronary bypass grafts or when the ascending aorta is short or atheromatous, limiting the space for proximal graft anastomosis. Unlike artery-to-artery composite grafts, which are resistant to flow-limiting technique-based distortions, the accurate construction of vein-to-vein anastomoses is critical. A technique is described that facilitates accurate placement of the anastomosis that prevents kinking, twisting or displacement.

  10. Shear-induced metastable states of end-grafted polystyrene

    SciTech Connect

    Sasa, Leslie A.; Yearley, Eric J.; Jablin, Michael S.; Majewski, Jaroslaw; Hjelm, Rex P.; Gilbertson, Robert D.; Lavine, Adrienne S.

    2011-08-15

    The in situ molecular scale response of end-grafted polystyrene to shear against a deuterated polystyrene melt was investigated with neutron reflectometry. The derived grafted polystyrene density profiles showed that the grafted polystyrene was retained on the quartz wafer during the measurements. The profiles suggested that the end-grafted polystyrene response to shear results in a series of metastable states, rather than equilibrium states assumed in the current theory. Except for some possible extension and/or contraction of the grafted polystyrene with shear, there was no obvious correlation between the grafted polymer structure and the shear thinning behavior observed in these samples.

  11. Engineering anatomically shaped human bone grafts.

    PubMed

    Grayson, Warren L; Fröhlich, Mirjam; Yeager, Keith; Bhumiratana, Sarindr; Chan, M Ete; Cannizzaro, Christopher; Wan, Leo Q; Liu, X Sherry; Guo, X Edward; Vunjak-Novakovic, Gordana

    2010-02-23

    The ability to engineer anatomically correct pieces of viable and functional human bone would have tremendous potential for bone reconstructions after congenital defects, cancer resections, and trauma. We report that clinically sized, anatomically shaped, viable human bone grafts can be engineered by using human mesenchymal stem cells (hMSCs) and a "biomimetic" scaffold-bioreactor system. We selected the temporomandibular joint (TMJ) condylar bone as our tissue model, because of its clinical importance and the challenges associated with its complex shape. Anatomically shaped scaffolds were generated from fully decellularized trabecular bone by using digitized clinical images, seeded with hMSCs, and cultured with interstitial flow of culture medium. A bioreactor with a chamber in the exact shape of a human TMJ was designed for controllable perfusion throughout the engineered construct. By 5 weeks of cultivation, tissue growth was evidenced by the formation of confluent layers of lamellar bone (by scanning electron microscopy), markedly increased volume of mineralized matrix (by quantitative microcomputer tomography), and the formation of osteoids (histologically). Within bone grafts of this size and complexity cells were fully viable at a physiologic density, likely an important factor of graft function. Moreover, the density and architecture of bone matrix correlated with the intensity and pattern of the interstitial flow, as determined in experimental and modeling studies. This approach has potential to overcome a critical hurdle-in vitro cultivation of viable bone grafts of complex geometries-to provide patient-specific bone grafts for craniofacial and orthopedic reconstructions.

  12. LVAD Outflow Graft Angle and Thrombosis Risk.

    PubMed

    Aliseda, Alberto; Chivukula, Venkat Keshav; Mcgah, Patrick; Prisco, Anthony R; Beckman, Jennifer A; Garcia, Guilherme J M; Mokadam, Nahush A; Mahr, Claudius

    This study quantifies thrombogenic potential (TP) of a wide range of left ventricular assist device (LVAD) outflow graft anastomosis angles through state-of-the-art techniques: 3D imaged-based patient-specific models created via virtual surgery and unsteady computational fluid dynamics with Lagrangian particle tracking. This study aims at clarifying the influence of a single parameter (outflow graft angle) on the thrombogenesis associated with flow patterns in the aortic root after LVAD implantation. This is an important and poorly-understood aspect of LVAD therapy, because several studies have shown strong inter and intrapatient thrombogenic variability and current LVAD implantation strategies do not incorporate outflow graft angle optimization. Accurate platelet-level investigation, enabled by statistical treatment of outliers in Lagrangian particle tracking, demonstrates a strong influence of outflow graft anastomoses angle on thrombogenicity (platelet residence times and activation state characterized by shear stress accumulation) with significantly reduced TP for acutely-angled anastomosed outflow grafts. The methodology presented in this study provides a device-neutral platform for conducting comprehensive thrombogenicity evaluation of LVAD surgical configurations, empowering optimal patient-focused surgical strategies for long-term treatment and care for advanced heart failure patients.

  13. Polymer Grafted Nanoparticle-based Oil Dispersants

    NASA Astrophysics Data System (ADS)

    Kim, Daehak; Krishnamoorti, Ramanan

    2015-03-01

    Particle-based oil dispersants mainly composed of inorganic nanoparticles such as silica nanoparticles are considered as environmentally friendly oil dispersants due to their biocompatibility and relatively low toxicity. The oil-water interfacial tension is reduced when nanoparticles segregate to the oil-water interface and this segregation is improved by grafting interfacially active polymer brushes. In this study, surfactant-like amphiphilic block copolymers were grafted from silica nanoparticles using an atom transfer radical polymerization (ATRP) method in order to increase their interfacial activity. We have studied the interfacial activity of such hybrid nanoparticles using pendant drop interfacial tension measurements, and their structure using small angle X-ray scattering. Amphiphilic copolymer grafted nanoparticles significantly reduced oil-water interfacial tension compared to the interfacial tension reduction induced by homopolymer grafted nanoparticles or the corresponding free ungrafted copolymer. Moreover, hard and stable oil-water emulsions were formed by applying the block copolymer grafted nanoparticles due to the formation of interparticle network structures, which were observed by cryo-scanning electron microscopy (SEM) and small angle neutron scattering (SANS)

  14. Comparison of different skin preservation methods with gamma irradiation.

    PubMed

    Guerrero, Linda; Camacho, Bernardo

    2017-02-11

    Allografts are in constant demand, not only for burn victims, but also for all open wounds as "biological dressings". Tissue quality and security are two of the major concerns of Tissue Banks. There are limited studies published. There has been extensive discussion on the subject of preservation methods for cadaver skin. Most literature available comes from clinical reports. In this research, the authors compared 85% glycerolized non irradiated skin allografts with three glycerolized irradiated skin allografts (using different glycerol concentrations 50%, 70% and 85%). The evaluation of allograft quality was done by measuring physical and biological properties of such prepared human tissue grafts. In the histological structure evaluation changes were minimal and did not alter the skin structure. The clinical function of their behavior as temporal dressings was tested. They proved to have similar capabilities for improving granulating tissue and contributing to wound beds closure (Hickerson et al. (1994) [1]).

  15. Induction of transplantation tolerance in mice across major histocompatibility barrier by using allogeneic thymus transplantation and total lymphoid irradiation

    SciTech Connect

    Waer, M.; Palathumpat, V.; Sobis, H.; Vandeputte, M. )

    1990-07-15

    The use of allogeneic thymus transplantation as a means of inducing tolerance across MHC barriers was investigated in thymectomized, total lymphoid irradiated BALB/c mice. In 90% of the animals long term outgrowth of histologically normal C57BL thymus grafts was observed. None of the latter animals was chimeric. All thymus graft-bearing mice showed specific nonresponsiveness for C57BL MHC Ag in mixed lymphocyte reaction and cell-mediated lympholysis. Spleen cells of the C57BL thymus-bearing mice were unable to induce lethal graft-vs-host disease in neonatal (BALB/c X C57BL) F1 mice but provoked a vigorous graft-vs-host disease reaction in (BALB/c x C3H) F1 neonates. Tolerant mice permanently accepted C57BL heart and pancreas grafts, but all rejected C3H grafts. Induction of tolerance of BALB/c pre-T cells through allogeneic thymus graft and/or specific suppressor cells seems to be involved. The present model offers new opportunities to study thymocyte maturation in a fully allogeneic environment and may yield applications for clinical organ transplantation.

  16. Why Do Grafts Clot Despite Access Blood Flow Surveillance?

    SciTech Connect

    Arbabzadeh, Massoud; Mepani, Bhupendra; Murray, Brian M.

    2002-12-15

    Purpose: To look in more detail at those grafts that clot despite access blood flow (ABF) surveillance and the outcome of radiological thrombectomy in those grafts. Methods: Retrospective review was carried out of all polytetrafluoroethylene grafts that clotted from September 1, 1998 to October 30, 2000. During this period, each graft had ABF measured monthly and was referred for prophylactic angioplasty if flow fell below 600 ml/min or by 25%. Results: Thirty-one of 62 monitored grafts clotted (0.44 episodes per patient per month). Five were surgically thrombectomized and 19 were radiologically thrombectomized. The last available ABF prior to graft thrombosis averaged 804 {+-} 108 ml/min and ranged from 215 to 2497 ml/min.Nine of the 23 grafts failed to trigger either of the ABF criteria prior to initial thrombosis. All but one of the 17 grafts throbolysedradiologically showed evidence of significant (>50%) venous stenoses,though additional lesions were found in nine. Thrombolysis was successful in 14 grafts, with ABF rising from 693 {+-} 96 to 941 {+-} 135 ml/min (p <0.05). Six additional grafts reclotted and were lost (6-month graft survival 37%). Conclusion: (1) A significant proportion (40%)of graft thromboses that occur despite ABF surveillance occur in grafts with preserved ABF (>600 ml/min); (2) over 70% can be successfully thrombectomized /angioplastied with about 35% long-term (6 months)survival.

  17. Inability of donor total body irradiation to prolong survival of vascularized bone allografts: Experimental study in the rat

    SciTech Connect

    Gonzalez del Pino, J.; Benito, M.; Randolph, M.A.; Weiland, A.J. )

    1990-07-01

    At the present time, the toxic side effects of recipient immunosuppression cannot be justified for human non-vital organ transplantation. Total body irradiation has proven effective in ablating various bone-marrow-derived and endothelial immunocompetent cellular populations, which are responsible for immune rejection against donor tissues. Irradiation at a dose of 10 Gy was given to donor rats six days prior to heterotopic transplantation of vascularized bone allografts to host animals. Another group of recipient rats also received a short-term (sixth to fourteenth day after grafting), low dose of cyclosporine. Total body irradiation was able merely to delay rejection of grafts across a strong histocompatibility barrier for one to two weeks, when compared to nonirradiated allografts. The combination of donor irradiation plus cyclosporine did not delay the immune response, and the rejection score was similar to that observed for control allografts. Consequently, allograft viability was quickly impaired, leading to irreversible bone damage. This study suggest that 10 Gy of donor total body irradiation delivered six days prior to grafting cannot circumvent the immune rejection in a vascularized allograft of bone across a strong histocompatibility barrier.

  18. Cold-Plasma Assisted Grafting of Paper

    NASA Astrophysics Data System (ADS)

    Gaiolas, C.; Costa, A. P.; Nunes, M.; Silva, M. J. Santos; Belgacem, M. N.

    2008-08-01

    The treatment of cellulose with cold-plasma in the presence of two silanes (vinyltrimethoxysilane and γ-methacryloxypropyltrimethoxysilane) was found to be efficient in grafting of cellulose macromolecules. The occurrence of the grafting was proved by contact angle measurement, ESCA and SEM. Thus, after solvent extraction of the modified substrates, in order to remove unbounded grafts, the polar component of the surface energy of treated samples decreased from 23 mJ/m2 to practically zero. The ESCA spectra showed the appearance of two new peaks at 102 and 150 eV, relative to the presence of Si atoms and a substantial increase in C1 signal, attributed to the enrichment of the surface by C-H moieties borne by the silanes.

  19. COLD-PLASMA ASSISTED GRAFTING OF PAPER

    SciTech Connect

    Gaiolas, C.; Costa, A. P.; Nunes, M.; Silva, M. J. Santos; Belgacem, M. N.

    2008-08-28

    The treatment of cellulose with cold-plasma in the presence of two silanes (vinyltrimethoxysilane and {gamma}-methacryloxypropyltrimethoxysilane) was found to be efficient in grafting of cellulose macromolecules. The occurrence of the grafting was proved by contact angle measurement, ESCA and SEM. Thus, after solvent extraction of the modified substrates, in order to remove unbounded grafts, the polar component of the surface energy of treated samples decreased from 23 mJ/m{sup 2} to practically zero. The ESCA spectra showed the appearance of two new peaks at 102 and 150 eV, relative to the presence of Si atoms and a substantial increase in C1 signal, attributed to the enrichment of the surface by C-H moieties borne by the silanes.

  20. [Fundamentals and principles of grafts and flaps].

    PubMed

    Cruz-Navarro, Natalio; León-Dueñas, Eduardo

    2014-01-01

    Reconstructive surgery of large urethral stenosis and the management of congenital anomalies such as hypospadias and epispadias require covering large cutaneous and mucosal defects with different techniques. The objective of this work is to define the main differences between tissues to be transferred and to study the principles that must govern the management of the various flaps and grafts used for these techniques. We analyze the anatomical and physiological features that may be key to understand the success and possible failures of these procedures, and we review technical details that must accompany in every case, not only during the operation, but also during the preoperative and postoperative period. We conclude stating that grafts (mainly oral and preputial mucosa) and flaps are increasingly used for the repair of urethral stenosis. Grafts must be prepared adequately in the back table and thinned to the maximum, and also be fixed properly, to guarantee their immobility until neovascularization is assured.

  1. Grafting Polymer Loops onto Functionalized Nanotubes: Monitoring Grafting and Loop Formation

    SciTech Connect

    Ashcraft, Earl C; Ji, Haining; Mays, Jimmy; Dadmun, Mark D

    2011-01-01

    Polystyrene functionalized at both ends (telechelic polymer) with epoxide groups (epoxy PS epoxy) was reacted with carboxylated multiwall carbon nanotubes (COOH MWNT) in solution in order to graft polymer chains at both ends onto the MWNT surface, forming loops. FT-IR spectroscopy was employed to monitor the formation of aromatic esters and to quantify the amount of telechelic grafted to the nanotube surface as a function of reaction time. When the samples were further annealed in the melt, an increase in the aromatic ester peak was observed, indicating that the unreacted chain ends further grafted to MWNT surfaces to form loops. By reacting the grafted nanotube samples further with monocarboxy terminated poly(4-methylstyrene) (COOH P4MS), the amount of epoxy PS epoxy that had only reacted at one end was determined. Reaction rate analysis indicates that that the grafting of epoxy PS epoxy to the nanotube surface is reaction controlled, as the FT-IR spectroscopy signal grows as a function of approximately t0.3. These studies exemplify how FT-IR spectroscopy can be used as a novel technique to quantify the amount of grafted polymer, grafting rate, and percent of difunctional polymers that form loops, and provide a method to create loop covered nanoparticles.

  2. Graft preservation solutions in cardiovascular surgery.

    PubMed

    Winkler, Bernhard; Reineke, David; Heinisch, Paul Philip; Schönhoff, Florian; Huber, Christoph; Kadner, Alexander; Englberger, Lars; Carrel, Thierry

    2016-08-01

    Vein grafts are still the most commonly used graft material in cardiovascular surgery and much effort has been spent in recent years on investigating the optimal harvesting technique. One other related topic of similar importance remained more or less an incidental one. The storage solutions of vein grafts following procurement and prior to implantation are, despite their assumed impact, a relatively neglected theme. There is no doubt that the endothelium plays a key role in long-term patency of vein grafts, but the effects of the different storage solutions on the endothelium remain unclear : In a review of the literature, we could find 20 specific papers that addressed the question, of which the currently available preservation solutions are superior, harmless, damaging or ineffective. The focus lies on saline and autologous whole blood. Besides these two storage media, novel or alternative solutions have been investigated with surprising findings. In addition, a few words will be spent on potential alternatives and novel solutions on the market. As there is currently no randomized clinical trial regarding saline versus autologous whole blood available, this review compares all previous studies and methods of analysis to provide a certain level of evidence on this topic. In summary, saline has negative effects on the endothelial layers and therefore may compromise graft patency. Related factors, such as distension pressure, may outbalance the initial benefit of autologous whole blood or storage solutions and intensify the harmful effects of warm saline. In addition, there is no uniform consent on the superiority of autologous whole blood for vein graft storage. This may open the door to alternatives such as the University of Wisconsin solution or one of the specific designed storage solutions like TiProtec™ or Somaluthion™. Whether these preservation solutions are superior or advantageous remains the subject of further studies.

  3. Carboxylated nanodiamonds inhibit γ-irradiation damage of human red blood cells.

    PubMed

    Santacruz-Gomez, K; Silva-Campa, E; Melendrez-Amavizca, R; Teran Arce, F; Mata-Haro, V; Landon, P B; Zhang, C; Pedroza-Montero, M; Lal, R

    2016-04-07

    Nanodiamonds when carboxylated (cNDs) act as reducing agents and hence could limit oxidative damage in biological systems. Gamma (γ)-irradiation of whole blood or its components is required in immunocompetent patients to prevent transfusion-associated graft versus host disease (TA-GVHD). However, γ-irradiation of blood also deoxygenates red blood cells (RBCs) and induces oxidative damage, including abnormalities in cellular membranes and hemolysis. Using atomic force microscopy (AFM) and Raman spectroscopy, we examined the effect of cNDs on γ-irradiation mediated deoxygenation and morphological damage of RBCs. γ-Radiation induced several morphological phenotypes, including stomatocytes, codocytes and echinocytes. While stomatocytes and codocytes are reversibly damaged RBCs, echinocytes are irreversibly damaged. AFM images show significantly fewer echinocytes among cND-treated γ-irradiated RBCs. The Raman spectra of γ-irradiated RBCs had more oxygenated hemoglobin patterns when cND-treated, resembling those of normal, non-irradiated RBCs, compared to the non-cND-treated RBCs. cND inhibited hemoglobin deoxygenation and morphological damage, possibly by neutralizing the free radicals generated during γ-irradiation. Thus cNDs have the therapeutic potential to preserve the quality of stored blood following γ-irradiation.

  4. ORNL irradiation creep facility

    SciTech Connect

    Reiley, T.C.; Auble, R.L.; Beckers, R.M.; Bloom, E.E.; Duncan, M.G.; Saltmarsh, M.J.; Shannon, R.H.

    1980-09-01

    A machine was developed at ORNL to measure the rates of elongation observed under irradiation in stressed materials. The source of radiation is a beam of 60 MeV alpha particles from the Oak Ridge Isochronous Cyclotron (ORIC). This choice allows experiments to be performed which simulate the effects of fast neutrons. A brief review of irradiation creep and experimental constraints associated with each measurement technique is given. Factors are presented which lead to the experimental choices made for the Irradiation Creep Facility (ICF). The ICF consists of a helium-filled chamber which houses a high-precision mechanical testing device. The specimen to be tested must be thermally stabilized with respect to the temperature fluctuations imposed by the particle beam which passes through the specimen. Electrical resistance of the specimen is the temperature control parameter chosen. Very high precision in length measurement and temperature control are required to detect the small elongation rates relevant to irradiation creep in the test periods available (approx. 1 day). The apparatus components and features required for the above are presented in some detail, along with the experimental procedures. The damage processes associated with light ions are discussed and displacement rates are calculated. Recent irradiation creep results are given, demonstrating the suitability of the apparatus for high resolution experiments. Also discussed is the suitability of the ICF for making high precision thermal creep measurements.

  5. Investigation of the formation of peroxide in. gamma. -irradiated polyethylene by the method of iodometric titration

    SciTech Connect

    Savost'yanov, V.S.; Kritskaya, D.A.; Ponomarev, A.N.

    1986-09-01

    The concentrations of hydroperoxides (HP) and dialkyl peroxides (DAP) in polyethylene (PE) powder, ..gamma.. irradiated in air at 295 K at a dose of 0.22-2.8 J/(kg x sec) up to doses of 16-300 kJ/kg, were determined by various methods of iodometric titration. Under the indicated conditions, the HP concentration reached 0.18 mole/kg, DPA 0.07 mole/kg, G /SUB HP/ was 8.3 1/100 eV; G /SUB GP/ ..integral..I /SUP -0.5/ . On the basis of the total absence of grafting of acrylamide onto ..gamma..-irradiated PE after reduction during titration of HP in it, it was concluded that grafted polymerization is initiated by the radicals of thermal decomposition of HP in PE.

  6. Platelet--arterial synthetic graft interaction and its modification

    SciTech Connect

    Callow, A.D.; Connolly, R.; O'Donnell, T.F. Jr.; Gembarowicz, R.; Keough, E.; Ramberg-Laskaris, K.; Valeri, C.R.

    1982-11-01

    We compared the in vivo platelet reactivity of two commonly used clinical grafts, Dacron and expanded polytetrafluoroethylene (PTFE), with that of a control autogenous artery graft and assessed whether platelet reactivity was modified by the platelet-antiaggregating agent prostacyclin (PGI2) (epoprostenol). Grafts were randomly placed into the carotid arteries of 21 baboons. Platelets labeled with /sup 111/In were infused within one hour after implantation graft for gamma camera scanning of platelet uptake. The accumulation of platelets on Dacron grafts began almost immediately after injection and reached a peak after one to two hours. The PTFE and control autogenous artery grafts accumulated comparable small amounts of platelets. Prostacyclin was then infused in a second series of baboons with Dacron grafts, at a rate of 150 to 200 ng/kg/min. It prevented the usual platelet uptake when administered concomitant with graft implantation and reduced previously established platelet activity.

  7. Vascularized bone graft from the supracondylar region of the femur.

    PubMed

    Doi, Kazuteru; Hattori, Yasunori

    2009-01-01

    Free vascularized thin corticoperiosteal grafts and small periosteal bone grafts harvested from the supracondylar region of the femur are described. These grafts are nourished from the articular branch of the descending genicular artery and vein. Unlike currently used vascularized bone grafts, this graft can be successfully harvested with disturbing the vascularity. Thin corticoperiosteal grafts consist of periosteum with a thin layer of outer cortical bone and include the cambium layer, which has a better osteogenic capacity. This graft is elastic and readily conforms to the recipient bed configuration. Thin corticoperiosteal grafts were used for fracture nonunion of the long bone with smaller bone defect and to treat forty-six patients with avascular necrosis of the body of the talus, scaphoid, and lunate bone.

  8. Conduits for Coronary Bypass: Vein Grafts

    PubMed Central

    Farkas, Emily A

    2012-01-01

    The saphenous vein has been the principal conduit for coronary bypass grafting from the beginning, circa 1970. This report briefly traces this history and concomitantly presents one surgeons experience and personal views on use of the vein graft. As such it is not exhaustive but meant to be practical with a modest number of references. The focus is that of providing guidance and perspective which may be at variance with that of others and recognizing that there may be many ways to accomplish the task at hand. Hopefully the surgeon in training/early career may find this instructive on the journey to surgical maturity. PMID:23130300

  9. Biodegradable metal adsorbent synthesized by graft polymerization onto nonwoven cotton fabric

    NASA Astrophysics Data System (ADS)

    Sekine, Ayako; Seko, Noriaki; Tamada, Masao; Suzuki, Yoshio

    2010-01-01

    A fibrous adsorbent for Hg ions was synthesized by radiation-induced emulsion graft polymerization of glycidyl methacrylate (GMA) onto a nonwoven cotton fabric and subsequent chemical modification. The optimal pre-irradiation dose for initiation of the graft polymerization of GMA, which minimized the effects of radiation damage on the mechanical strength of the nonwoven cotton fabric, was found to be 10 kGy. The GMA-grafted nonwoven cotton fabric was subsequently modified with ethylenediamine (EDA) or diethylenetriamine (DETA) to obtain a Hg adsorbent. The resulting amine-type adsorbents were evaluated for batch and continuous adsorption of Hg. In batch adsorption, the distribution coefficients of Hg reached 1.9×10 5 and 1.0×10 5 for EDA- and DETA-type adsorbents, respectively. A column packed with EDA-type adsorbent removed Hg from 1.8 ppm Hg solution at a space velocity of 100 h -1, which corresponds to 16,000 times the volume of the packed adsorbent. The adsorbed Hg on the EDA-type adsorbent could be completely eluted by 1 M HCl solution. A microbial oxidative degradation test revealed that the EDA-type adsorbent is biodegradable.

  10. Radiation-induced graft copolymerization of dimethylaminoethyl methacrylate onto graphene oxide for Cr(VI) removal

    NASA Astrophysics Data System (ADS)

    Ma, Hui-Ling; Zhang, Youwei; Zhang, Long; Wang, Liancai; Sun, Chao; Liu, Pinggui; He, Lihua; Zeng, Xinmiao; Zhai, Maolin

    2016-07-01

    Dimethylaminoethyl methacrylate (DMAEMA)-grafted graphene oxide hybrid materials (GO-g-P) were fabricated using γ-ray irradiation at ambient temperature. The morphology and structure of GO-g-P were characterized by Fourier-transform infrared spectroscopy (FT-IR), X-ray photoelectron (XPS), thermogravimetric analysis (TGA) and X-ray diffraction (XRD). It was confirmed that DMAEMA was grafted successfully on the surface of graphene sheet. The grafting yield of GO-g-P increased with monomer concentration (0-2.5 mol L-1) and dose (0-40 kGy). The resulting adsorbent (GO-g-P) with amine groups was highly efficient for removing Cr(VI) from its acidic aqueous solution and could be easily separated by filtration. The optimum pH for Cr(VI) removal was observed at pH 1.1 and the Cr(VI) uptake of GO-g-P at this pH was 82.4 mg g-1.

  11. Photodynamic damage to cartilage and synovial tissue grafted on a chick's chorioallantoic membrane

    NASA Astrophysics Data System (ADS)

    Fisher, M.; Nahir, A. M.; Kimel, Sol

    1997-09-01

    Rheumatoid arthritis (RA) is a chronic inflammatory disease of the synovial joints causing pain deformities and disability. The highly vascular inflamed synovium has aggressive and destructive characteristics, it invades, erodes and gradually destroys cartilage and underlying bone. Photodynamic therapy (PDT) was performed using the chick chorioallantoic membrane (CAM) model to investigate the vitality of synovium and cartilage implanted on the CAM. Synovium, obtained from human patients, was grafted onto the CAM; gross microscopy and histology proved its vitality 7 days post grafting. Cartilage obtained from rabbit knee joint was also maintained on the CAM for 7 days. Its vitality was demonstrated by histology and by measuring metabolic and enzymatic activity of cartilage cells (chondrocytes) as well as the collagen and proteoglycans content. Selective PDT was performed using aluminum phthalocyanine tetrasulfonate (AlPcS4), a hydrophilic compound, soluble in biological solutions, as a photosensitizer. After irradiation with a diode laser (lambda equals 670 nm, 10 mW) damage was observed in vascularized synovium grafts, whereas avascular cartilage remained intact.

  12. Autologous Bone Graft in Foot and Ankle Surgery.

    PubMed

    Miller, Christopher P; Chiodo, Christopher P

    2016-12-01

    Bone graft is a common adjunct procedure in orthopedic surgery used for fusions, fracture repair, and the reconstruction of skeletal defects in the foot and ankle. Autologous graft, or autograft, involves the transport of bone from a donor site to another location in the same patient. It is considered by many to be the gold standard of bone grafting, as it is provides all biologic factors required for functional graft. Further, autograft is 100% histocompatible with no risk of disease transmission.

  13. Segmental pancreatic allograft survival in baboons treated with combined irradiation and cyclosporine: a preliminary report

    SciTech Connect

    du Toit, D.F.; Heydenrych, J.J.; Smit, B.; Louw, G.; Zuurmond, T.; Laker, L.; Els, D.; Weideman, A.; Wolfe-Coote, S.; van der Merwe, E.A.

    1985-04-01

    The present study was undertaken to evaluate the effectiveness of cyclosporine (CS) alone, total lymphoid irradiation (TLI) alone, and CS in combination with total body irradiation (TBI) in suppressing segmental pancreatic allograft rejection in totally pancreatectomized outbred chacma baboons. The administration of CS 25 mg/kg/day and 50 mg/ kg/day resulted in mean graft survival of 21.5 days and 24.5 days, respectively. CS 85 mg/kg/day resulted in median graft survival of 9 days. There was a wide daily fluctuation of CS serum trough levels exhibited between primates receiving the same oral dose. TBI in excess of 300 rads resulted in irreversible bone marrow suppression. Modest results were achieved in recipients of TBI-76 rads (38 x 2 rads), with median graft survival of 21 days, results not different from recipients treated with CS. TLI recipients of 600 rads (150 x 4 rads) resulted in median pancreatic graft survival of 16 days. TBI together with oral CS administration exhibited no synergistic or additive effect and a single peroperative donor-specific blood transfusion did not enhance pancreatic allograft survival in this model. However, of 10 primates receiving TBI 100 rads (50 x 2 rads) and CS 25 mg/kg/day administered orally indefinitely, four remained normoglycemic for more than 60 days. TBI 100 rads (50 x 2 rads) together with oral and parenteral CS resulted in necrotizing enterocolitis in four of six recipients.

  14. Kidney allograft survival in dogs treated with total lymphoid irradiation

    SciTech Connect

    Howard, R.J.; Sutherland, D.E.R.; Lum, C.T.; Lewis, W.I.; Kim, T.H.; Slavin, S.; Najarian, J.S.

    1981-02-01

    Total lymphoid irradiation (TLI) is immunosuppressive and, in rodents, can induce a state where transplantation of allogenic bone marrow results in chimerism and permanent acceptance of organ allografts from the donor strain. Twelve splenectomized dogs were treated with TLI (150 rads per fraction, total dose 1950 to 3000 rads) before bilateral nephrectomy and renal allotransplantation. Eight dogs received bone marrow from the kidney donor. In 13 untreated control dogs renal allografts functioned for a mean +- (SE) of 4.7 +- 0.3 days. In the four TLI treated dogs who did not receive bone marrow the renal allografts functioned for 15 to 76 days (two dogs died with functioning grafts). In the eight TLI treated dogs who received donor bone marrow, two died immediately after transplantation, two rejected at 3 and 13 days, one died at 13 days with a functioning graft, and two have had the grafts function for longer than 500 days. Chimerism was not detected in the one dog tested. The response of peripheral blood lymphocytes to stimulation with phytohemaglutinin and in mixed lymphocyte culture was suppressed for at least one month after TLI. The results confirm the immunosuppressive effect of TLI. The absence of kidney rejection in two recipients of donor bone marrow show the potential of this approach to induce long-term immunologic unresponsiveness as to an organ allograft, but the outcome is unpredictable and further experiments are needed to define the optimal conditions for administration of TLI and bone marrow to the recipients.

  15. Superhydrophobic bio-fibre surfaces via tailored grafting architecture.

    PubMed

    Nyström, Daniel; Lindqvist, Josefina; Ostmark, Emma; Hult, Anders; Malmström, Eva

    2006-09-14

    Superhydrophobic bio-fibre surfaces with a micro-nano-binary surface structure have been achieved via the surface-confined grafting of glycidyl methacrylate, using a branched "graft-on-graft" architecture, followed by post-functionalisation to obtain fluorinated brushes.

  16. 21 CFR 872.3930 - Bone grafting material.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Bone grafting material. 872.3930 Section 872.3930...) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3930 Bone grafting material. (a) Identification. Bone grafting material is a material such as hydroxyapatite, tricalcium phosphate, polylactic...

  17. 21 CFR 872.3930 - Bone grafting material.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Bone grafting material. 872.3930 Section 872.3930...) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3930 Bone grafting material. (a) Identification. Bone grafting material is a material such as hydroxyapatite, tricalcium phosphate, polylactic...

  18. 21 CFR 872.3930 - Bone grafting material.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Bone grafting material. 872.3930 Section 872.3930...) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3930 Bone grafting material. (a) Identification. Bone grafting material is a material such as hydroxyapatite, tricalcium phosphate, polylactic...

  19. Defense mechanisms involved in disease resistance of grafted vegetables

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Vegetable grafting with resistant rootstocks is an effective strategy to control a variety of soil-borne diseases and root-knot nematodes in the Cucurbitaceae and Solanaceae. In addition, improved resistance to some foliar diseases and viruses has also been reported in grafted plants. Hence, graft...

  20. Immobilization of peroxidase on SPEU film via radiation grafting

    NASA Astrophysics Data System (ADS)

    Hongfei, Ha; Guanghui, Wang; Jilan, Wu

    The acrylic acid or acrylamide were grafted via radiation onto segmented polyetherurethane (SPEU) film which is a kind of biocompatible material. Then the Horse radish peroxidase was immobilized on the grafted SPEU film through chemical binding. Some quantitative relationships between the percent graft and the activity, amount of immobilized enzyme were given. The properties and application of obtained biomaterial was studied as well.

  1. Adding value to grafted watermelon: Novel benefits and potential pitfalls

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Grafted watermelons are commonly used in Asia and areas of Europe but are not widely used in the United States. The traditional reason for grafting watermelons has been for resistance to soil borne diseases such as Fusarium. We began to explore novel benefits which might make grafted watermelons m...

  2. Superoxide generation and cytotactic response of irradiated neutrophils

    SciTech Connect

    Eastlund, D.T.; Charbonneau, T.T.

    1988-07-01

    Irradiation of blood components has been used to prevent transfusion-related graft-versus-host disease (GVHD) in immunocompromised patients. This study was designed to determine the effect of irradiation on neutrophil aggregation, chemotaxis, and superoxide generation. Purified neutrophils were irradiated with a Cesium source at four doses ranging from 0 to 17,500 rads. Formyl-methionyl-leucyl-phenylalanine (FMLP) and zymosan-treated serum (ZTS) cytotaxin-induced chemotaxis and migration were determined in the agarose assay. Neutrophil aggregation to FMLP was determined by aggregometry. Superoxide generation and random migration were not affected by irradiation at doses up to 17,500 rads. When compared to nonirradiated controls, the chemotactic response to ZTS remained normal, with an insignificant decline from 174 +/- 31.0 to 150 +/- 42.3 (mean +/- SD) units. The chemotactic response to FMLP declined insignificantly, from 228 +/- 31.3 at 0 rad to 207 +/- 26.4 at 17,500 rads. The aggregation response to FMLP remained within the normal range but declined from 0.78 +/- 0.11 to 0.61 +/- 0.18. At the radiation doses currently used to reduce the risk of transfusion-related GVHD, neutrophil superoxide generation and chemotactic response remain essentially normal.

  3. Production of high melt strength polypropylene by gamma irradiation

    NASA Astrophysics Data System (ADS)

    Lugão, A. B.; Artel, B. W. H.; Yoshiga, A.; Lima, L. F. C. P.; Parra, D. F.; Bueno, J. R.; Liberman, S.; Farrah, M.; Terçariol, W. R.; Otaguro, H.

    2007-11-01

    High melt strength polypropylene (HMS-PP) has been recently developed and introduced in the market by the major international producers of polypropylene. Therefore, BRASKEM, the leading Brazilian PP producer, together with EMBRARAD, the leading Brazilian gamma irradiator, and the IPEN (Institute of Nuclear Energy and Research) worked to develop a national technology for the production of HMS-PP. One of the effective approaches to improve melt strength and extensibility is to add chain branches onto polypropylene backbone using gamma radiation. Branching and grafting result from the radical combinations during irradiation process. Crosslinking and main chain scission in the polymer structure are also obtained during this process. In this work, gamma irradiation technique was used to induce chemical changes in commercial polypropylene with two different monomers, Tri-allyl-isocyanurate (TAIC) and Tri-methylolpropane-trimethacrylate (TMPTMA), with concentration ranging from 1.5 to 5.0 mmol/100 g of polypropylene. These samples were irradiated with a 60Co source at dose of 20 kGy. It used two different methods of HMS-PP processing. The crosslinking of modified polymers was studied by measuring gel content melt flow rate and rheological properties like melt strength and drawability. It was observed that the reaction method and the monomer type have influenced the properties. However, the concentration variation of monomer has no effect.

  4. FOOD IRRADIATION REACTOR

    DOEpatents

    Leyse, C.F.; Putnam, G.E.

    1961-05-01

    An irradiation apparatus is described. It comprises a pressure vessel, a neutronic reactor active portion having a substantially greater height than diameter in the pressure vessel, an annular tank surrounding and spaced from the pressure vessel containing an aqueous indium/sup 1//sup 1//sup 5/ sulfate solution of approximately 600 grams per liter concentration, means for circulating separate coolants through the active portion and the space between the annular tank and the pressure vessel, radiator means adapted to receive the materials to be irradiated, and means for flowing the indium/sup 1//sup 1//sup 5/ sulfate solution through the radiator means.

  5. Fuel or irradiation subassembly

    DOEpatents

    Seim, O.S.; Hutter, E.

    1975-12-23

    A subassembly for use in a nuclear reactor is described which incorporates a loose bundle of fuel or irradiation pins enclosed within an inner tube which in turn is enclosed within an outer coolant tube and includes a locking comb consisting of a head extending through one side of the inner sleeve and a plurality of teeth which extend through the other side of the inner sleeve while engaging annular undercut portions in the bottom portion of the fuel or irradiation pins to prevent movement of the pins.

  6. Improved adhesion, growth and maturation of vascular smooth muscle cells on polyethylene grafted with bioactive molecules and carbon particles.

    PubMed

    Parizek, Martin; Kasalkova, Nikola; Bacakova, Lucie; Slepicka, Petr; Lisa, Vera; Blazkova, Martina; Svorcik, Vaclav

    2009-11-20

    High-density polyethylene (PE) foils were modified by an Ar(+) plasma discharge and subsequent grafting with biomolecules, namely glycine (Gly), polyethylene glycol (PEG), bovine serum albumin (BSA), colloidal carbon particles (C) or BSA and C (BSA + C). As revealed by atomic force microscopy (AFM), goniometry and Rutherford Backscattering Spectroscopy (RBS), the surface chemical structure and surface morphology of PE changed dramatically after plasma treatment. The contact angle decreased for the samples treated by plasma, mainly in relation to the formation of oxygen structures during plasma irradiation. A further decrease in the contact angle was obvious after glycine and PEG grafting. The increase in oxygen concentration after glycine and PEG grafting proved that the two molecules were chemically linked to the plasma-activated surface. Plasma treatment led to ablation of the PE surface layer, thus the surface morphology was changed and the surface roughness was increased. The materials were then seeded with vascular smooth muscle cells (VSMC) derived from rat aorta and incubated in a DMEM medium with fetal bovine serum. Generally, the cells adhered and grew better on modified rather than on unmodified PE samples. Immunofluorescence showed that focal adhesion plaques containing talin, vinculin and paxillin were most apparent in cells on PE grafted with PEG or BSA + C, and the fibres containing alpha-actin, beta-actin or SM1 and SM2 myosins were thicker, more numerous and more brightly stained in the cells on all modified PE samples than on pristine PE. An enzyme-linked immunosorbent assay (ELISA) revealed increased concentrations of focal adhesion proteins talin and vinculin and also a cytoskeletal protein beta-actin in cells on PE modified with BSA + C. A contractile protein alpha-actin was increased in cells on PE grafted with PEG or Gly. These results showed that PE activated with plasma and subsequently grafted with bioactive molecules and colloidal C

  7. Improved Adhesion, Growth and Maturation of Vascular Smooth Muscle Cells on Polyethylene Grafted with Bioactive Molecules and Carbon Particles

    PubMed Central

    Parizek, Martin; Kasalkova, Nikola; Bacakova, Lucie; Slepicka, Petr; Lisa, Vera; Blazkova, Martina; Svorcik, Vaclav

    2009-01-01

    High-density polyethylene (PE) foils were modified by an Ar+ plasma discharge and subsequent grafting with biomolecules, namely glycine (Gly), polyethylene glycol (PEG), bovine serum albumin (BSA), colloidal carbon particles (C) or BSA and C (BSA + C). As revealed by atomic force microscopy (AFM), goniometry and Rutherford Backscattering Spectroscopy (RBS), the surface chemical structure and surface morphology of PE changed dramatically after plasma treatment. The contact angle decreased for the samples treated by plasma, mainly in relation to the formation of oxygen structures during plasma irradiation. A further decrease in the contact angle was obvious after glycine and PEG grafting. The increase in oxygen concentration after glycine and PEG grafting proved that the two molecules were chemically linked to the plasma-activated surface. Plasma treatment led to ablation of the PE surface layer, thus the surface morphology was changed and the surface roughness was increased. The materials were then seeded with vascular smooth muscle cells (VSMC) derived from rat aorta and incubated in a DMEM medium with fetal bovine serum. Generally, the cells adhered and grew better on modified rather than on unmodified PE samples. Immunofluorescence showed that focal adhesion plaques containing talin, vinculin and paxillin were most apparent in cells on PE grafted with PEG or BSA + C, and the fibres containing α-actin, β-actin or SM1 and SM2 myosins were thicker, more numerous and more brightly stained in the cells on all modified PE samples than on pristine PE. An enzyme-linked immunosorbent assay (ELISA) revealed increased concentrations of focal adhesion proteins talin and vinculin and also a cytoskeletal protein β-actin in cells on PE modified with BSA + C. A contractile protein α-actin was increased in cells on PE grafted with PEG or Gly. These results showed that PE activated with plasma and subsequently grafted with bioactive molecules and colloidal C particles

  8. Treatment of Secondary Stent-Graft Collapse After Endovascular Stent-Grafting for Iliac Artery Pseudoaneurysms

    SciTech Connect

    Clevert, D.-A. Stickel, M.; Steitz, H.-O.; Kopp, R.; Strautz, T.; Flach, P.; Johnson, T.; Jung, E.M.; Jauch, K.W.; Reiser, M.

    2007-02-15

    We report the case of a patient who developed an asymptomatic pseudoaneurysm in the left external iliac artery after transplant nephrectomy. The pseudoaneurysm most probably arose as a suture aneurysm from the external iliac artery after removal of the graft renal artery. Obviously we can not exclude the possibility it was a true aneurysm, although this seems much less likely. The pseudoaneurysm was detected during a routine CT scan and was treated interventionally with a stent-graft. One month later the asymptomatic patient underwent a vascular ultrasound examination including color Doppler, power Doppler, and B-flow as a routine control. An endoleak with collapse of the stent-graft was diagnosed. There was no evidence of stent infection. At a reintervention, the pseudoaneurysm was successfully treated using two uncovered Palmaz stents at the proximal and distal edge of the stent graft. Peri- and post-interventional ultrasound and CT angiography confirmed the exclusion of the aneurysm without an endoleak.

  9. Adoptive transfer of unresponsiveness to allogeneic skin grafts with hepatic gamma delta + T cells.

    PubMed Central

    Gorczynski, R M

    1994-01-01

    C3H/HEJ mice injected with irradiated multiple minor incompatible B10.BR lymphoid cells via the portal vein showed delayed rejection of subsequent B10.BR skin grafts. Similar delayed rejection was produced by lateral tail vein injection of B10.BR hepatic mononuclear cells or H-2k cells pulsed in vivo with B10 minor histocompatibility antigens. Inhibition of C3H anti-B10.BR immunity in vivo (assessed by delayed graft rejection) and in vitro (assessed by B10.BR-induced lymphokine production) can be transferred by radioresistant, plastic-adherent F4/80+33D1-CD4-CD8-alpha beta TcR-gamma delta TcR- mononuclear hepatic cells from (C3H/HEJ x C3H.SW)F1 mice injected 36 hr earlier with 100 x 10(6) irradiated spleen cells. By 10 days post-injection, cells transferring delayed rejection are radiosensitive, plastic non-adherent, F4/80-33D1-CD4-CD8- alpha beta Tc+- gamma delta TcR+ cells. Injection of interleukin-2 (IL-2) in vivo into mice receiving pretreatment with B10.BR cells via the portal vein, or adoptive transfer into such mice of immune anti-B10.BR lymphoid cells, abolished delayed rejection on subsequent skin grafting. Delayed rejection or modulation of lymphokine production was associated in all cases with suppression of IL-2 production and preferential retention of IL-4 production from cells stimulated in vitro. PMID:8132216

  10. Electron Beam Materials Irradiators

    NASA Astrophysics Data System (ADS)

    Cleland, Marshall R.

    2012-06-01

    Radiation processing is a well established method for enhancing the properties of materials and commercial products by treating them with ionizing energy in the form of high-energy electrons, X-rays, and gamma rays. Beneficial effects include polymerizing, cross-linking, grafting and degrading plastics, sterilizing single-use medical devices, disinfecting and disinfesting fresh foods, purifying drinking water, treating wastewater and other toxic waste materials that harm the environment, and many other applications that are still being evaluated. Industrial electron accelerators of several types have been developed and are being used for these applications. More than 1800 electron accelerators are presently installed in facilities worldwide for these purposes.

  11. Osteogenic activity of bone marrow-derived mesenchymal stem cells (BMSCs) seeded on irradiated allogenic bone.

    PubMed

    Tohma, Yasuaki; Dohi, Yoshiko; Ohgushi, Hajime; Tadokoro, Mika; Akahane, Manabu; Tanaka, Yasuhito

    2012-02-01

    Allogenic bone grafting, a technique used in orthopaedic surgery, has several problems, including low osteogenic activity. To overcome the problem, this study aimed to determine whether in vivo osteogenesis could be enhanced using allogenic irradiated bone grafts after seeding with autologous bone marrow-derived mesenchymal stem cells (BMSCs). The allogenic bone cylinders were extracted from ACI rats and sterilized by irradiation. Donor BMSCs were obtained from fresh Fischer 344 (F344) rat bone marrow by cell culture. The allogenic bone with or without BMSCs were transplanted subcutaneously into syngeneic F344 rats. At 4 weeks after transplantation, high alkaline phosphatase (ALP) activity, bone-specific osteocalcin mRNA expression and newly formed bone were detected in the allogenic bone with BMSCs. The origin of the newly formed bone was derived from cultured donor BMSCs. However, none of these identifiers of osteogenesis were detected in either the fresh or the irradiated allogenic bone without BMSCs. These results indicate the availability of autologous BMSCs to heighten the osteogenic response of allogenic bone. Our present tissue-engineering method might contribute to a wide variety of allogenic bone grafting techniques in clinical settings.

  12. Grafted silane monolayers: reconsideration of growth mechanisms

    NASA Astrophysics Data System (ADS)

    Ivanov, D. A.; Nysten, B.; Jonas, A. M.; Legras, R.

    1998-03-01

    Chemical force microscopy is a new technique devised to image chemical heterogeneities on surfaces. It requires the chemical modification of Atomic Force Microscopy (AFM) tips in order to create chemical probes. In this respect, self-assembled monolayers (SAM) of alkylchlorosilanes are particularly interesting as modifying agents for AFM tips. We report here our results on the kinetics of silanization and on the structure of such SAM's grafted on model surfaces (hydroxylated Si(100) wafers). AFM, contact angle measurements, X-ray reflectivity and X-ray photoelectron spectroscopy were used to characterize SAM's of octadecyltrichlorosilane (OTS) and octadecyldimethylchlorosilane (ODMS) grown from hexadecane and toluene solutions. The mechanism of grafting of OTS follows two stages. The first rapid stage corresponds to the nucleation and growth of island-like monolayer domains. The second slower stage is related to the densification of the monolayer. SAM's of ODMS were found to form thinner layers as compared to OTS, due to their lower grafting density probably resulting in a more disordered state of grafted alkyl chains. We also address the problems concerning the relationships between the quality of final SAM structures and the water content as well as the nature of the solvent used for silanization.

  13. Skin flaps and grafts -- self-care

    MedlinePlus

    ... drainage from the wound Drainage becoming thick, tan, green, or yellow, or smells bad (pus) Your temperature is above 100°F (37.8°C) for more than 4 hours Red streaks appear that lead away from the wound Alternative Names Autograft - self-care; Skin transplant - self-care; Split-skin graft - self- ...

  14. [Pseudoaneurysm of saphenous vein graft after CABG].

    PubMed

    Nakamura, T; Shimamoto, M; Yamazaki, F; Fujita, S; Yoshimura, T; Ueno, T; Shinozaki, T

    1995-04-01

    A 69-year-old man was admitted because of angina pectoris and thoracic descending aorta aneurysm. Staged operations were planned. First, he underwent CABG (coronary artery bypass grafting) with SVGs (saphenous vein grafts) to #4 PD, #7 and #12. Aprotinin was administrated to reduce blood loss. The routine postoperative graft angiography and enhanced CT showed a pseudoaneurysm in the SVG to #4 PD. We planned an elective operation of pseudoaneurysm repair and graft replacement of thoracic descending aorta. Also in this second operation, continuous infusion of aprotinin was started after the induction of anesthesia. About 30 minutes later, he suddenly fell in shock and cardiac arrest. Partial cardiopulmonary bypass was established and median sternotomy was performed. In the mediastinum, no bleeding was found. We found out a bleeding point of the SVG to #4 PD and a hemostatic clip on the right ventricule, and closed the bleeding point with suture. The cause of the pseudoaneurysm seemed to be defluxion of the hemostatic clip for a side brunch of the SVG. The cause of the preoperative shock may be an anaphylaxis to readministrated aprotinin.

  15. Endothelialized ePTFE Graft by Nanobiotechnology

    ClinicalTrials.gov

    2013-11-29

    The Apparatus for Processing the Tubular Graft Modification Will be Designed and Evaluated.; The On-site Capturing of the Endothelial (Progenitor) Cells by Peptide-mediated Selective Adhesion in Vitro and in Vivo Will Also be Elucidated.; The Patency Rate of ITRI-made Artificial Blood Vessels Will be Evaluated by the Porcine Animal Model.

  16. Dynamics of solvent-free grafted nanoparticles

    NASA Astrophysics Data System (ADS)

    Chremos, Alexandros; Panagiotopoulos, Athanassios Z.; Koch, Donald L.

    2012-01-01

    The diffusivity and structural relaxation characteristics of oligomer-grafted nanoparticles have been investigated with simulations of a previously proposed coarse-grained model at atmospheric pressure. Solvent-free, polymer-grafted nanoparticles as well as grafted nanoparticles in a melt were compared to a reference system of bare (ungrafted) particles in a melt. Whereas longer chains lead to a larger hydrodynamic radius and lower relative diffusivity for grafted particles in a melt, bulk solvent-free nanoparticles with longer chains have higher relative diffusivities than their short chain counterparts. Solvent-free nanoparticles with short chains undergo a glass transition as indicated by a vanishing diffusivity, diverging structural relaxation time and the formation of body-centered-cubic-like order. Nanoparticles with longer chains exhibit a more gradual increase in the structural relaxation time with decreasing temperature and concomitantly increasing particle volume fraction. The diffusivity of the long chain nanoparticles exhibits a minimum at an intermediate temperature and volume fraction where the polymer brushes of neighboring particles overlap, but must stretch to fill the interparticle space.

  17. Enhancement of surface nonwettability by grafting loops.

    PubMed

    Pei, Han-Wen; Liu, Xiao-Li; Liu, Hong; Zhu, You-Liang; Lu, Zhong-Yuan

    2017-02-08

    We present a computer simulation study on the nonwettability of a flat surface tethered with deformable looped polymer chains. Two kinds of loops are studied: monodispersed loops (loops with the same length) and polydispersed loops (loops with different lengths). Both kinds of loops include two arrangements: with regularly tethered sites and with randomly tethered sites. Regularly grafted loops form typical grooves on the surface, while randomly grafted loops form a more rugged surface. For monodispersed loops, we analyze the factors that influence the nonwettability when varying the rigidity of the loops. The loops are divided into two categories based on their rigidity according to our previous analysis procedure (Phys. Chem. Chem. Phys., 2016, 18, 18767-18775): rigid loops and flexible loops. It is found that the loop can partially form a re-entrant-like structure, which is helpful to increase the nonwettability of the surface. The surfaces with grafted loops have increased nonwettability, especially those grafted with flexible chains. However, the contact angle on the loop structure cannot further increase for the rigid chains due to a large top layer density (Phys. Chem. Chem. Phys., 2016, 18, 18767-18775). For polydispersed loops, the contact angle is highly related to the rigidity of the long loops that contact the droplet. Different from monodispersed loops, the mechanism of the nonwettability of polydispersed loops is attributed to the supporting ability (rigidity) of long loops.

  18. Grafting functional antioxidants on highly crosslinked polyethylene

    NASA Astrophysics Data System (ADS)

    Al-Malaika, S.; Riasat, S.; Lewucha, C.

    2016-05-01

    The problem of interference of antioxidants, such as hindered phenols, with peroxide-initiated crosslinking of polyethylene was addressed through the use of functional (reactive) graftable antioxidants (g-AO). Reactive derivatives of hindered phenol and hindered amine antioxidants were synthesised, characterised and used to investigate their grafting reactions in high density polyethylene; both non-crosslinked (PE) and highly peroxide-crosslinked (PEXa). Assessment of the extent of in-situ grafting of the antioxidants, their retention after exhaustive solvent extraction in PE and PEXa, and the stabilising performance of the grafted antioxidants (g-AO) in the polymer were examined and benchmarked against conventionally stabilised crosslinked & non-crosslinked polyethylene. It was shown that the functional antioxidants graft to a high extent in PEXa, and that the level of interference of the g-AOs with the polymer crosslinking process was minimal compared to that of conventional antioxidants which bear the same antioxidant function. The much higher level of retention of the g-AOs in PEXa after exhaustive solvent extraction, compared to that of the corresponding conventional antioxidants, accounts for their superior long-term thermal stabilising performance under severe extractive conditions.

  19. Fatal Saccharomyces Cerevisiae Aortic Graft Infection

    NASA Technical Reports Server (NTRS)

    Meyer, Michael (Technical Monitor); Smith, Davey; Metzgar, David; Wills, Christopher; Fierer, Joshua

    2002-01-01

    Saccharomyces cerevisiae is a yeast commonly used in baking and a frequent colonizer of human mucosal surfaces. It is considered relatively nonpathogenic in immunocompetent adults. We present a case of S. cerevisiae fungemia and aortic graft infection in an immunocompetent adult. This is the first reported case of S. cerevisiue fungemia where the identity of the pathogen was confirmed by rRNA sequencing.

  20. Effect of gamma radiation on the mechanical and barrier properties of HEMA grafted chitosan-based films

    NASA Astrophysics Data System (ADS)

    Khan, Avik; Huq, Tanzina; Khan, Ruhul A.; Dussault, Dominic; Salmieri, Stephane; Lacroix, Monique

    2012-08-01

    Chitosan films were prepared by dissolving 1% (w/v) chitosan powder in 2% (w/v) aqueous acetic acid solution. Chitosan films were prepared by solution casting. The values of puncture strength (PS), viscoelasticity coefficient and water vapor permeability (WVP) of the films were found to be 565 N/mm, 35%, and 3.30 g mm/m2 day kPa, respectively. Chitosan solution was exposed to gamma irradiation (0.1-5 kGy) and it was revealed that PS values were reduced significantly (p≤0.05) after 1 kGy dose and it was not possible to form films after 5 kGy. Monomer, 2-hydroxyethyl methacrylate (HEMA) solution (0.1-1%, w/v) was incorporated into the chitosan solution and the formulation was exposed to gamma irradiation (0.3 kGy). A 0.1% (w/v) HEMA concentration at 0.3 kGy dose was found optimal-based on PS values for chitosan grafting. Then radiation dose (0.1-5 kGy) was optimized for HEMA grafting. The highest PS values (672 N/mm) were found at 0.7 kGy. The WVP of the grafted films improved significantly (p≤0.05) with the rise of radiation dose.

  1. Homogeneous graft copolymerization of styrene onto cellulose in a sulfur dioxide-diethylamine-dimethyl sulfoxide cellulose solvent

    SciTech Connect

    Tsuzuki, M.; Hagiwara, I.; Shiraishi, N.; Yokota, T.

    1980-12-01

    Graft copolymerization of styrene onto cellulose was studied in a homogeneous system (SO/sub 2/(liquid)- diethylamine (DEA)-dimethyl sulfoxide (DMSO) medium)) by ..gamma..-ray mutual irradiation technique. At the same time, homopolymerization of styrene was also examined separately in DMSO, SO/sub 2/-DMSO, DEA-DMSO, and SO/sub 2/-DEA-DMSO media by the same technique. Polymerization of styrene hardly occurs on concentrations above 10 mole SO/sub 2/-DEA complex per mole glucose unit. Maximum percent grafting was obtained in concentrations of 4 mole, after which it decreased rapidly. Total conversion and percent grafting increased with the irradiation time. The value (=0.55) of the slope of the total conversion rate plotted against the dose was only a little higher than the 1/2 which was expected from normal kinetics. No retardation in homopolymerization of styrene in DMSO, SO/sub 2/-DMSO, and DEA-DMSO was evident, while the retardation of homopolymerization in the SO/sub 2/-DEA-DMSO medium was measurable. Sulfur atoms were detected in the polymers obtained in both of SO/sub 2/-DMSO and SO/sub 2/-DEA-DMSO solutions. All of the molecular weights of polymers obtained in the present experiment were very low (3.9 x 10/sup 3/-1.75 x 10/sup 4/).

  2. Study of polypropylene/polybutene blends modified by gamma irradiation and (high melt strength polypropylene)/polybutene blends

    NASA Astrophysics Data System (ADS)

    Yoshiga, Adriana; Otaguro, Harumi; Lima, Luís Filipe C. P.; Artel, Beatriz W. H.; Parra, Duclerc F.; Rodrigues Bueno, Jeferson; Shinzato, Rodrigo; Farrah, Marcelo; Lugão, Ademar B.

    2007-12-01

    It is well-known that polypropylene (PP) is difficult to process as a consequence of its linear structure. It is also known that grafting of long-chain branches on PP backbone using ionizing radiation is an effective approach to achieve high melt strength polypropylene (HMS PP). Chain-scission and, in minor extend, crosslinking and grafting are the predominant reaction in order to branch PP backbone. However, if multifunctional monomers are used to promote the grafting reaction, crosslinking can surpass chain scission and grafting, reducing drawability. Therefore, in an effort to enhance the processability and so the drawability, it has been found helpful to add a small amount of polybutene-1. Gamma irradiation technique was used to induce chemical changes in blends of PP and polybutene in acetylene atmosphere (crosslinker promoter) and in HMSPP/polybutene blends. The samples were irradiated with a 60Co source with doses of 12.5 and 20 kGy in the presence of acetylene. In this work, two different methods of blends processing were compared regarding rheological and mechanical properties. Effects on the strength and elongation at the yield point and at rupture were observed by mechanical tests and showed decrease of tensile strength and increase of elongation at rupture for samples obtained by irradiation of blends. The results from rheology demonstrated an increase in melt strength and drawability of blends.

  3. Host NKT cells can prevent graft-versus-host disease and permit graft antitumor activity after bone marrow transplantation.

    PubMed

    Pillai, Asha B; George, Tracy I; Dutt, Suparna; Teo, Pearline; Strober, Samuel

    2007-05-15

    Allogeneic bone marrow transplantation is a curative treatment for leukemia and lymphoma, but graft-vs-host disease (GVHD) remains a major complication. Using a GVHD protective nonmyeloablative conditioning regimen of total lymphoid irradiation and antithymocyte serum (TLI/ATS) in mice that has been recently adapted to clinical studies, we show that regulatory host NKT cells prevent the expansion and tissue inflammation induced by donor T cells, but allow retention of the killing activity of donor T cells against the BCL1 B cell lymphoma. Whereas wild-type hosts given transplants from wild-type donors were protected against progressive tumor growth and lethal GVHD, NKT cell-deficient CD1d-/- and Jalpha-18-/- host mice given wild-type transplants cleared the tumor cells but died of GVHD. In contrast, wild-type hosts given transplants from CD8-/- or perforin-/- donors had progressive tumor growth without GVHD. Injection of host-type NKT cells into Jalpha-18-/- host mice conditioned with TLI/ATS markedly reduced the early expansion and colon injury induced by donor T cells. In conclusion, after TLI/ATS host conditioning and allogeneic bone marrow transplantation, host NKT cells can separate the proinflammatory and tumor cytolytic functions of donor T cells.

  4. Modulation of graft architectures for enhancing hydrophobic interaction of biomolecules with thermoresponsive polymer-grafted surfaces.

    PubMed

    Idota, Naokazu; Kikuchi, Akihiko; Kobayashi, Jun; Sakai, Kiyotaka; Okano, Teruo

    2012-11-01

    This paper describes the effects of graft architecture of poly(N-isopropylacrylamide) (PIPAAm) brush surfaces on thermoresponsive aqueous wettability changes and the temperature-dependent hydrophobic interaction of steroids in silica capillaries (I.D.: 50 μm). PIPAAm brushes were grafted onto glass substrates by surface-initiated atom transfer radical polymerization (ATRP) that is one of the living radical polymerization techniques. Increases in the graft density and chain length of PIPAAm brushes increased the hydration of polymer brushes, resulting in the increased hydrophilic properties of the surface below the transition temperature of PIPAAm at 32 °C. More hydrophobic surface properties were also observed on surfaces modified with the block copolymers of IPAAm and n-butyl methacrylate (BMA) than that with IPAAm homopolymer-grafted surfaces over the transition temperature. Using PBMA-b-PIPAAm-grafted silica capillaries, the baseline separation of steroids was successfully achieved by only changing temperature. The incorporation of hydrophobic PBMA chains in grafted PIPAAm enhanced the hydrophobic interaction with testosterone above the transition temperature. The surface modification of hydrophobicity-enhanced thermoresponsive polymers is a promising method for the preparation of thermoresponsive biointerfaces that can effectively modulated their biomolecule and cell adsorption with the wide dynamic range of hydrophilic/hydrophobic property change across the transition temperature.

  5. Irradiating insect pests

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This is a non-technical article focusing on phytosanitary uses of irradiation. In a series of interview questions, I present information on the scope of the invasive species problem and the contribution of international trade in agricultural products to the movement of invasive insects. This is foll...

  6. Update on meat irradiation

    SciTech Connect

    Olson, D.G.

    1997-12-01

    The irradiation of meat and poultry in the United States is intended to eliminate pathogenic bacteria from raw product, preferably after packaging to prevent recontamination. Irradiation will also increase the shelf life of raw meat and poultry products approximately two to three times the normal shelf life. Current clearances in the United States are for poultry (fresh or frozen) at doses from 1.5 to 3.0 kGy and for fresh pork at doses from 0.3 to 1.0 kGy. A petition for the clearance of all red meat was submitted to the Food and Drug Administration (FDA) in July 1994. The petition is for clearances of fresh meat at doses from 1.5 to 4.5 kGy and for frozen meat at {approximately}2.5 to 7.5 kGy. Clearance for red meat is expected before the end of 1997. There are 28 countries that have food irradiation clearances, of which 18 countries have clearances for meat or poultry. However, there are no uniform categories or approved doses for meat and poultry among the countries that could hamper international trade of irradiated meat and poultry.

  7. Phytosanitary applications of irradiation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phytosanitary treatments are used to disinfest agricultural commodities of quarantine pests so the commodities can be shipped across quarantine barriers to trade. Ionizing irradiation is a promising treatment that is increasing in use. Almost 19,000 tons of sweet potatoes and several fruits, plus ...

  8. Generic phytosanitary irradiation treatments

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The history of the development of generic phytosanitary irradiation (PI) treatments is discussed beginning with its initial proposal in 1986. Generic PI treatments in use today are 150 Gy for all hosts of Tephritidae, 250 Gy for all arthropods on mango and papaya shipped from Australia to New Zeala...

  9. NSUF Irradiated Materials Library

    SciTech Connect

    Cole, James Irvin

    2015-09-01

    The Nuclear Science User Facilities has been in the process of establishing an innovative Irradiated Materials Library concept for maximizing the value of previous and on-going materials and nuclear fuels irradiation test campaigns, including utilization of real-world components retrieved from current and decommissioned reactors. When the ATR national scientific user facility was established in 2007 one of the goals of the program was to establish a library of irradiated samples for users to access and conduct research through competitively reviewed proposal process. As part of the initial effort, staff at the user facility identified legacy materials from previous programs that are still being stored in laboratories and hot-cell facilities at the INL. In addition other materials of interest were identified that are being stored outside the INL that the current owners have volunteered to enter into the library. Finally, over the course of the last several years, the ATR NSUF has irradiated more than 3500 specimens as part of NSUF competitively awarded research projects. The Logistics of managing this large inventory of highly radioactive poses unique challenges. This document will describe materials in the library, outline the policy for accessing these materials and put forth a strategy for making new additions to the library as well as establishing guidelines for minimum pedigree needed to be included in the library to limit the amount of material stored indefinitely without identified value.

  10. Influence of relaxation transitions on radiation-initiated cationic graft polymerization. [Gamma radiation

    SciTech Connect

    Kudryavtsev, V.N.; Kabanov, V.Ya.; Chalykh, A.E.; Spitsyn, V.I.

    1982-05-01

    Radiation grafting of vinyl n-butyl ether (VBE) to polyvinyl chloride (PVC) over a broad temperature range was investigated. The relaxation transitions in the PVC/VBE system were also determined. Grafting of vinyl alkyl ethers proceeds entirely by a cationic mechanism in a reaction medium that has been dried to a water concentration no greater than 0.1-1.0 ppm. In this connection, the diffusion properties of water in the temperature region were studied. Commercial films of unplasticized PVC (thickness 200 M); were subjected to swelling in two systems: in a 50% solution of VBE in benzene at 25/sup 0/C, and in the pure monomer at 40/sup 0/C. The reaction mixtures were first dried over metallic sodium in a deaerated atmosphere. The specimens were irradiated in a Co gamma-radiation unit to a dose of 10 kGy at a dose rate of 3 Gy/sec. The first reaction mixture was investigated over a range of temperatures from -60/sup 0/ to +70/sup 0/C, and the second from -15/sup 0/ to +50/sup 0/C. The degree of grafting was determined from the increase in weight of the original ungrafted film. The temperature was held to within +/-1/sup 0/C. The relaxation transitions in the swollen polymer systems were determined by two methods, thermostimulated current (TSC) and thermomechanics (TM). It was found that in the region of the glass transition of a swollen PVC-VBE system, radiation-initiated cationic graft polymerization proceeds at a maximal rate, and there are changes in state of the water molecules (the agents of breaking the ion reaction chain) and in their diffusion properties within the matrix.

  11. Delayed Graft Function 5 Months After Living Donor Kidney Transplantation

    PubMed Central

    Schulz, Tim; Pries, Alexandra; Kapischke, Matthias

    2016-01-01

    Patient: Female, 59 Final Diagnosis: Delayed kidney graft function Symptoms: — Medication: — Clinical Procedure: Living donor kidney transplantation Specialty: Transplantology Objective: Unusual clinical course Background: Delayed graft function is a clinical term to describe the failure of the transplanted kidney to function immediately after transplantation. Case Report: A 59-year-old woman suffered from a rare case of delayed graft function lasting 148 days after unrelated living donor kidney transplantation. Until now, 15 years after transplantation, organ function is still good, with serum creatinine levels about 1.4 to 2.0 mg/dl. Conclusions: Even after prolonged graft dysfunction, good graft function can be achieved. PMID:26915643

  12. Novel treatment of an 11-cm saphenous vein graft aneurysm.

    PubMed

    Harrison, Joshua W; Swartz, Michael F; Fink, Gregory W

    2009-04-01

    Saphenous vein graft pseudoaneurysms are rare and potentially fatal complications after coronary artery bypass graft surgery. Here we present an 11-cm saphenous vein graft pseudoaneurysm from a 20-year-old vein graft to the obtuse marginal artery. The pseudoaneurysm was directly located beneath the sternum and adjacent to two patent grafts. Therefore, we used a novel approach to access the aorta through a right thoracotomy, and using a pericardial patch, we closed the ostia to the pseudoaneurysm. Postoperatively there was no longer flow into the aneurysm, and at 1-year follow-up the patient is doing well.

  13. Bone graft and mesenchimal stem cells: clinical observations and histological analysis

    PubMed Central

    Bertolai, Roberto; Catelani, Carlo; Aversa, Alessandro; Rossi, Alessandro; Giannini, Domenico; Bani, Daniele

    2015-01-01

    Summary Autologous bone, for its osteoconductive, osteoinductive and osteogenetic properties, has been considered to be the gold standard for maxillary sinus augmentation procedures. Autograft procedures bring also some disadvantages: sometimes the limited amount of available intraoral bone makes necessary to obtain bone from an extraoral site, and this carries an associated morbidity. To overcome this problem we started using homologous freeze-dried bone in maxillary sinus augmentation procedures. This bone is industrially processed with γ-irradiation to eliminate its disease transmission potential and it’s considered safe, but this treatment also eliminates the osteoinductive and osteogenetic properties, making it just an inert scaffold for regeneration. Mesenchymal stem cells are successfully used in and orthopedic surgery for their amplification potential of healing mechanisms. We assumed that mesenchymal stem cells can restore the osteogenetic and osteoinductive properties in homologous bone grafts. The aim of this study was an histological evaluation of bone regeneration in maxillary sinus elevation using: 1) mesenchymal stem cells engineered freeze-dried bone allografts; 2) freeze-dried bone allografts. Twenty patients (10M, 10F) with a mean age of 55.2 years affected by severe maxillary atrophy were treated with bilateral maxillary sinus floor elevation. For each patient were randomly assigned a “test” side and a “control” side, different from each other exclusively in the composition of the graft material. The “control” sides were composed by corticocancellous freeze-dried bone chips and the “test” sides were composed by corticocancellous freeze-dried bone chips engineered in a bone marrow mesenchymal stem cells concentrate. After three months bone biopsies were performed on the grafts and histological specimens were made in order to evaluate the healed bone from an histological point of view. Histologically all the specimens showed

  14. Graft rejection by cytolytic T cells. Specificity of the effector mechanism in the rejection of allogeneic marrow

    SciTech Connect

    Nakamura, H.; Gress, R.E. )

    1990-02-01

    Cellular effector mechanisms of allograft rejection remain incompletely described. Characterizing the rejection of foreign-marrow allografts rather than solid-organ grafts has the advantage that the cellular composition of the marrow graft, as a single cell suspension, can be altered to include cellular components with differing antigen expression. Rejection of marrow grafts is sensitive to lethal doses of radiation in the mouse but resistant to sublethal levels of radiation. In an effort to identify cells mediating host resistance, lymphocytes were isolated and cloned from spleens of mice 7 days after sublethal TBI (650 cGy) and inoculation with allogeneic marrow. All clones isolated were cytolytic with specificity for MHC encoded gene products of the allogeneic marrow donor. When cloned cells were transferred in vivo into lethally irradiated (1025 cGy) recipients unable to reject allogeneic marrow, results utilizing splenic 125IUdR uptake indicated that these MHC-specific cytotoxic clones could suppress marrow proliferation. In order to characterize the effector mechanism and the ability of the clones to affect final engraftment, double donor chimeras were constructed so that 2 target cell populations differing at the MHC from each other and from the host were present in the same marrow allograft. Results directly demonstrated an ability of CTL of host MHC type to mediate graft rejection and characterized the effector mechanism as one with specificity for MHC gene products.

  15. Radiation induced emulsion graft polymerization of 4-vinylpyridine onto PE/PP nonwoven fabric for As(V) adsorption

    NASA Astrophysics Data System (ADS)

    Akkaş Kavaklı, Pınar; Kavaklı, Cengiz; Seko, Noriaki; Tamada, Masao; Güven, Olgun

    2016-10-01

    A novel nonwoven fabric adsorbent having 4-vinylpyridine functional groups was prepared by using radiation-induced emulsion graft polymerization method and grafting 4-vinylpyridine monomer onto a polyethylene-coated polypropylene nonwoven fabric (NWF) in aqueous emulsion solution. The grafting conditions of the 4-vinylpyridine monomer onto the NWF were optimised and 150% Dg VP-g-NWF was prepared using 30 kGy pre-irradiation dose, 5% VP monomer concentration and 0.5% (w/w) Tween 20 in aqueous emulsion. Grafted 4-vinylpyridine chains on the NWF were then quaternized for the preparation of QVP-g-NWF adsorbent. All fabric structures were characterized by using Fourier-transform infrared spectrometer, x-ray photoelectron spectrometer and scanning electron microscope. QVP-g-NWF adsorbent was used in batch adsorption experiments for As(V) ions by studying the pH, contact time, and initial As(V) ion concentration parameters. Results showed that QVP-g-NWF adsorbent has significant As(V) adsorption and experimental As(V) adsorption capacity was 98.04 mg As(V)/g polymer from 500 mg/L initial As(V) concentration at pH 7.00.

  16. UV-induced graft polymerization of acrylic acid in the sub-micronchannels of oxidized PET track-etched membrane

    NASA Astrophysics Data System (ADS)

    Korolkov, Ilya V.; Mashentseva, Anastassiya A.; Güven, Olgun; Taltenov, Abzal A.

    2015-12-01

    In this article, we report on functionalization of track-etched membrane based on poly(ethylene terephthalate) (PET TeMs) oxidized by advanced oxidation systems and by grafting of acrylic acid using photochemical initiation technique for the purpose of increasing functionality thus expanding its practical application. Among advanced oxidation processes (H2O2/UV) system had been chosen to introduce maximum concentration of carboxylic acid groups. Benzophenone (BP) photo-initiator was first immobilized on the surfaces of cylindrical pores which were later filled with aq. acrylic acid solution. UV-irradiation from both sides of PET TeMs has led to the formation of grafted poly(acrylic acid) (PAA) chains inside the membrane sub-micronchannels. Effect of oxygen-rich surface of PET TeMs on BP adsorption and subsequent process of photo-induced graft polymerization of acrylic acid (AA) were studied by ESR. The surface of oxidized and AA grafted PET TeMs was characterized by UV-vis, ATR-FTIR, XPS spectroscopies and by SEM.

  17. Comb-type grafted poly(N-isopropylacrylamide) gel modified surfaces for rapid detachment of cell sheet.

    PubMed

    Tang, Zhonglan; Akiyama, Yoshikatsu; Yamato, Masayuki; Okano, Teruo

    2010-10-01

    A comb-type grafted poly(N-isopropylacrylamide) (PIPAAm) gel modified surface was newly developed for providing a rapid cell sheet recovery for tissue engineering. PIPAAm macromonomer was prepared by the etherification reaction of the hydroxyl terminal moieties of PIPAAm with acryloyl chloride, followed by the radical telomerization reaction of N-isopropylacrylamide (IPAAm) monomer using 2-mercaptoethanol as a chain transfer agent. Solution containing IPAAm monomer and PIPAAm macromonomer was spread on the surface of tissue culture polystyrene (TCPS), and then the surface was subjected to electron beam irradiation for grafting the monomer and macromonomer on the surfaces, resulting in comb-type grafted PIPAAm gel modified TCPS (GG-TCPS). Besides the difference of the amount of the modified PIPAAm, no distinct difference was found between the properties of GG-TCPSs and normal-type PIPAAm gel modified TCPS (NG-TCPS) through XPS, AFM and a contact angle measurement. At 37 degrees C, bovine aortic endothelial cells (BAECs) were well adhered and spread on GG-TCPS as well as NG-TCPS regardless of the macromonomer concentration. By lowering temperature to 20 degrees C, BAECs detached themselves more rapidly from GG-TCPS compared with NG-TCPS. Upon lowering temperature, the grafted polymer was speculated to accelerate the hydration of modified PIPAAm gel, resulting in a rapid cell sheet detachment.

  18. Synthesis and characterization of N-vinylcaprolactam/N,N-dimethylacrylamide grafted onto chitosan networks by gamma radiation

    NASA Astrophysics Data System (ADS)

    Pérez-Calixto, M. P.; Ortega, A.; Garcia-Uriostegui, L.; Burillo, G.

    2016-02-01

    N-vinylcaprolactam (NVCL) and N,N-dimethylacrylamide (DMAAm) were grafted onto crosslinked chitosan by gamma radiation, using direct and indirect (pre-irradiation oxidative) methods. The binary graft systems were synthesized in one and two steps to evaluate the influences of architecture on the properties of the polymeric material. Maximum grafting percentages were obtained by the direct method. The different systems obtained were characterized by FTIR and TGA. The equilibrium swelling time of the (net-CS)-g-NVCL/DMAAm and [(net-CS)-g-NVCL]-g-DMAAm systems was 75 and 25 min, respectively, while crosslinked CS required about 24 h. Thermal and pH sensitivity were conserved in all systems; the pH response in [(net-CS)-g-NVCL]-g-DMAAm (LCST: 37°, pH: 5.2) is more defined than (net-CS)-g-NVCL/DMAAm (LCST: 37 °C, pH: 3.8). Grafting radiation showed to be an effective technique to modify CS hydrogels.

  19. Assessment of bone repair following the use of anorganic bone graft and membrane associated or not to 830-nm laser light

    NASA Astrophysics Data System (ADS)

    de Assis Limeira, Francisco, Jr.; Barbosa Pinheiro, Antônio L.; Marquez de Martinez Gerbi, Marleny E.; Pedreira Ramalho, Luciana Maria; Marzola, Clovis; Carneiro Ponzi, Elizabeth A.; Soares, Andre O.; Bandeira de Carvalho, Lívia C.; Vieira Lima, Helena Cristina; Oliveira Gonçalves, Thais; Silva Meireles, Gyselle C.; Possa, Thaise R.

    2003-06-01

    The aim of this study was to assess the effect of LLLT (λ830nm, Thera lase, DMC Equipmentos, Sao Carlos, SP, Brazil, 40mW, CW, spot size 0.60mm, 16J/cm2 per session) on the repair of bone defects on the femur of Wistar albinus rats which were grafted with anorganic bovine bone associated or not to bovine bone membrane. Five randomized groups were studied: I (Control); II (anorganic bovine bone); III (anorganic bovine bone + LLLT); IV (anorganic bovine bone + bovine bone membrane) and V (anorganic bovine bone + bovine bone membrane + LLLT). The animals were irradiated at every 48h during 15 days, the first irradiation was performed immediately after the procedure. The animals were irradiated transcutaneuosly in four points around the defect. At each point a dose of 4J/cm2 was given (f~0,60mm, 40mW) totaling 16J/cm2 per session. The animals were sacrificed 15, 21 and 30 days after surgery. The specimens were routinely processed to wax and stained with H&E and Picrosírius stains and analyzed under light microscopy. The results showed evidence of a more advanced repair on the irradiated groups when compared to non-irradiated ones. The repair of irradiated groups was characterized by both increased bone formation and amount of collagen fibers around the graft within the cavity early, considering the osteoconductive capacity of the anorganic bovine bone and the increment of the cortical repair in specimens with membrane. It is concluded that LLLT had a positive effect on the repair of bone defect submitted the implantation of graft associated or not to the use of biological membrane.

  20. Food irradiation: Activities and potentialities

    NASA Astrophysics Data System (ADS)

    Doellstaedt, R.; Huebner, G.

    After the acceptance of food irradiation up to an overall average dose of 10 kGy recommended by the Joint FAO/IAEA/WHO Expert Committee on the Wholesomeness of Irradiated Food in October 1980, the G.D.R. started a programme for the development of techniques for food irradiation. A special onion irradiator was designed and built as a pilot plant for studying technological and economic parameters of the irradiation of onions. The new principle of bulk-cargo irradiation allows the integration of this technology into the usual harvest technology for onions on the way from field to storage. Scientific and applied research work has been carried out in the past 3 yr on the irradiation of spices, potatoes, eviscerated chicken, animal feeds, fodder yeast, drugs and vaccines. In connection with the irradiation of eviscerated chicken, fodder yeast and animal feeds the basis of an antisalmonella programme has been discussed. Germ-count-reduced spices were employed for the production of test charges of preserves and tinned products. The results have led to the decision to design and build a new multipurpose irradiator for food irradiation. In order to cover the legal aspects of food irradiation the Ministry of Health issued regulations concerning the recommendation of irradiated food in the G.D.R.