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1.
Med J Armed Forces India ; 79(3): 280-285, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37193527

RESUMEN

Background: Obstetrics as a speciality has a very long association with the transfusion services and poses its own set of immunohematological (IHL) challenges. A study was carried out to evaluate the spectrum of IHL issues in obstetrics in our setup and to suggest a way forward. Methods: This study was carried out in a transfusion services setup catering to antenatal care (ANC) clientele in two tertiary-level health care setups. Samples were collected from all ANC patients requiring transfusion and patients reporting for Indirect Coombs Test (ICT). Data included ICT positive cases with implicated alloantibodies, those requiring specialised procedures and the foetal outcome. The results were described using descriptive statistics by frequencies and percentages. Results: A total of 4683 eligible samples were included in the study, out of 21,893 antenatal patients visiting our setup during study period. One hundred thirty-six ANC patient samples were found to be ICT positive. The most common single alloantibody was anti-D (n = 77, 57.5%). Double antibody positivity was found in 28 patients. Multiple alloantibodies were found in 1 patient. Up to 48% of these allo-anti D cases necessitated specialised procedures. Conclusion: The IHL issues of obstetrics faced in our setup are no less than that in Indian population. We have much higher frequency of double alloantibody in our ANC population. The authors propose that all multiparous ANC patients, especially with a history of transfusion, irrespective of Rh D status should be screened for irregular alloantibodies to circumvent these issues and the last-minute rush for provision of compatible units.

2.
Med J Armed Forces India ; 78(Suppl 1): S226-S231, 2022 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-36147414

RESUMEN

Background: General guidelines describing the potential indications and contraindications of Fresh Frozen Plasma (FFP) exist. However, their implementation is inadequate, leading to inappropriate use in various clinical settings. This study aims to define the appropriateness of the FFP usage in terms of therapeutic versus prophylactic indications. Methods: Retrospective audit was conducted over one year prior to and after an educational intervention (1122 patients for 6072 FFP units and 1061 patients for 4858 FFP units, respectively). Clinical diagnosis, indication for FFP transfusion, and coagulation profile were noted, and episodes of transfusion were divided into appropriate and inappropriate based on the guidelines of the British Committee for Standards in Hematology (2004 reviewed in 2018) and College of American Pathologists (1994). Results: Initial audit found 51.8% of FFP transfusions to be inappropriate (3069 of 5922). Coagulation profile (with INR values less than 1.5 times of the normal) was the most common cause of inappropriate transfusion (15.08%). 56.7% of FFP were prophylactically transfused. Re-audit after educational interventions showed a 22.3% reduction in the number of inappropriate transfusions. Conclusion: Inappropriate, as well as high prophylactic usage of FFP, was noticed in the initial audit, which reduced significantly after educational interventions. Regular CMEs, interactive sessions with clinicians, functioning Hospital Transfusion Committees, and prospective audits can affirm, further improve and reinforce the existing Hospital Transfusion Guidelines.

3.
Med J Armed Forces India ; 78(3): 296-301, 2022 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-35855709

RESUMEN

Background: Treatment with high-dose chemotherapy and stem cell transplantation has prolonged survival in patients of multiple myeloma (MM). A dose-response relationship between number of CD34+ cells infused and leukocyte and platelet recovery, exists. Patients receiving dose of <2.0 × 106 CD34+ cells/kg have delayed engraftment. The level of optimal cutoff for accelerated engraftment is yet to be validated. Hence, this study was undertaken to study the association of CD 34+ cell dose with engraftment kinetics in patients of MM who underwent autolgous peripheral blood stem cell transplant (PBSCT). Methods: We retrospectively analyzed 19 patients of MM who underwent PBSCT at our center between December 2016 to December 2018. Complete blood counts were carried out daily after transplantation to record neutrophil and platelet engraftment. Results: Based on the CD34+ cell dose given : <5 × 106/kg (category 1), 5-10 × 106/kg (category 2), >5 × 106/kg (category 3), the mean (SD) neutrophil engraftment time was 11.3 (0.5) days, 10.6 (0.9) days, and 10.2 (1.3) days respectively. Platelet engraftment time was 12.4 (2.60) days, 10.6 (1.14) days, and 11.2 (1.64) days for category 1, 2, and 3 patients, respectively. Correlation co-efficient between CD 34+cell dose and days for neutrophil and platelet engraftment was found to be -0.24 and -0.20, respectively. Time for neutrophil engraftment was found to be significantly associated with CD34+ cell dose category. Conclusion: CD 34+ cell dose appears as the strongest predictor of leukocyte and platelet engraftment. CD 34+ cell dose of >5.0 × 106 cells/kg leads to an accelerated neutrophil and platelet engraftment in patients of MM.

4.
J Org Chem ; 86(10): 7242-7255, 2021 May 21.
Artículo en Inglés | MEDLINE | ID: mdl-33949861

RESUMEN

Dehalogenative deuteration reactions are generally performed through metal-mediated processes. This report demonstrates a mild protocol for hydrodehalogenation and dehalogenative deuteration of aryl/heteroaryl halides (39 examples) using a reduced odd alternant hydrocarbon phenalenyl under transition metal-free conditions and has been employed successfully for the incorporation of deuterium in various biologically active compounds. The combined approach of experimental and theoretical studies revealed a single electron transfer-based mechanism.

5.
J Sci Food Agric ; 101(13): 5378-5390, 2021 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-33644855

RESUMEN

BACKGROUND: Consumptive water footprint (CWF) is a comprehensive measure of water consumption by paddy and can be used to assess the impact on freshwater volume. The seasonal water consumption and water footprints of paddy under any irrigation practice vary with changing the transplanting dates. The present study aimed to investigate the impact of shifting transplanting dates on CWFs of paddy under the system of rice intensification (SRI) using a crop model. A medium-duration variety (IR-36) was cultivated during kharif (monsoon) and rabi (non-monsoon) seasons of 2015/16 and 2016/17. The field data were used to calibrate and validate the crop model, Agricultural Production Systems Simulator (APSIM)-Oryza, as well as simulate paddy yield, evapotranspiration and consumptive water footprints (CWFs) under different transplanting dates. RESULTS: The APSIM-Oryza simulated grain yield was found to be closely matched with the observed yield during both calibration (r2  = 0.98, root-mean-square error < 300 kg ha-1 ) and validation (r2  = 0.88, root-mean-square error < 400 kg ha-1 ). The seasonal water savings in SRI practice was 18-21% compared to conventional, with an effect of a 20-30% improvement in the yield. The early transplanting on 1 July in kharif and 15 December in rabi can produce maximum grain yields of 4.55 and 5.15 t ha-1 , respectively, with a minimum CWF of 1064 and 855 m3 t-1 under SRI for the study region. CONCLUSION: The comparison of yield and CWF scenarios under different transplanting dates revealed the superiority of early transplanting in terms of yield improvement with the least irrigation requirement and CWF under SRI. © 2021 Society of Chemical Industry.


Asunto(s)
Riego Agrícola/métodos , Oryza/metabolismo , Agua/análisis , Modelos Biológicos , Oryza/crecimiento & desarrollo , Estaciones del Año , Suelo/química , Agua/metabolismo
6.
Asian J Transfus Sci ; 18(1): 73-78, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39036689

RESUMEN

INTRODUCTION: Hepcidin is the key regulator of systemic iron homeostasis. In iron-loading anemias, hepcidin levels are regulated by opposite forces of erythropoiesis and iron overload. In ß-thalassemia major patients, transfusions are the predominant cause of iron overload; in such chronically transfused patients, hepcidin concentrations are significantly higher than nontransfused patients, due to both increased iron load of transfusions and the suppression of ineffective erythropoiesis. AIM: This study aims to evaluate the effect of blood transfusions on serum hepcidin levels in chronically transfused patients of ß-thalassemia major and correlate with hemoglobin and serum ferritin levels of pre- and posttransfusion. MATERIALS AND METHODS: Thirty-three ß-thalassemia major patients requiring monthly transfusions were included in the study. Blood samples, collected pretransfusion and 7 days posttransfusion, were evaluated for hemoglobin, serum ferritin, and serum hepcidin using enzyme immunoassay. STATISTICAL ANALYSIS: Data were statistically analyzed through SPSS software and P < 0.05 is considered statically significant. RESULTS: Posttransfusion levels of hemoglobin, serum ferritin, and serum hepcidin increased. Posttransfusion levels of hepcidin were near normal levels. Pre- and posttransfusion hepcidin concentrations were significantly associated with hemoglobin levels. CONCLUSION: Serum hepcidin concentrations vary depending on the degree of erythropoiesis drive and level of anemia. We found that the serum hepcidin levels decrease over the inter-transfusion interval and transfusions cause suppression of ineffective erythropoiesis by the increase in hemoglobin. Posttransfusion values of hepcidin in our study were closer to normal levels which may be due to lower erythropoietic drive posttransfusion. We suggest that the measurement of serum hepcidin in chronically transfused ß-thalassemia patients can be used as a follow-up investigation for better management of these patients.

7.
Chem Sci ; 14(10): 2606-2615, 2023 Mar 08.
Artículo en Inglés | MEDLINE | ID: mdl-36908958

RESUMEN

Solid-state radical generation is an attractive but underutilized methodology in the catalytic strong bond activation process, such as the aryl-halide bond. Traditionally, such a process of strong bond activation relied upon the use of transition metal complexes or strongly reducing photocatalysts in organic solvents. The generation of the aryl radical from aryl halides in the absence of transition-metal or external stimuli, such as light or cathodic current, remains an elusive process. In this study, we describe a reduced organic hydrocarbon, which can act as a super reductant in the solid state to activate strong bonds by solid-state single electron transfer (SSSET) under the influence of mechanical energy leading to a catalytic strategy based on the mechano-SSSET or mechanoredox process. Here, we investigate the solid-state synthesis of the super electron donor phenalenyl anion in a ball mill and its application as an active catalyst in strong bond (aryl halide) activation. Aryl radicals generated from aryl halides by employing this strategy are competent for various carbon-carbon bond-forming reactions under solvent-free and transition metal-free conditions. We illustrate this approach for partially soluble or insoluble polyaromatic arenes in accomplishing solid-solid C-C cross-coupling catalysis, which is otherwise difficult to achieve by traditional methods using solvents.

8.
Hematol Transfus Cell Ther ; 45(4): 456-460, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-36273983

RESUMEN

INTRODUCTION: Approximately 55.52% of the Indian population had been fully vaccinated by Jan. 2022, since its first roll out on January 16, 2021. A few concerns were raised concerning the Covishield vaccination related to thrombotic thrombocytopenia. Apheresis-derived platelet concentrates are frequently required in a plethora of clinical situations and post-vaccination decrement of platelet counts might lead to increased deferral of the platelet-pheresis donors. OBJECTIVES: The aim of the study was to discover the effect of the Covishield vaccination on deferral rates of plateletpheresis donors. METHODS: Blood samples were collected from the potential platelet donors for the completion of the standard questionnaire for the complete blood count. The data collected were tabulated in the MS Excel spreadsheet and the biostatistical analysis was performed with the SPSS v23. A p-value of < 0.05 was taken as significant. We compared this data with age- and sex-matched controls. RESULTS: The mean age of cases and controls was 29.69 ± 8.57 and 30.15 ± 7.11, respectively. There was a significant difference in platelet counts of cases (188496.35 ± 72065.66/cumm) and controls (269524.50 ± 53981.60/cumm). Furthermore, donors who received one dose had higher platelet counts of 248676.47 ± 80075.24/cumm than those who received both doses of vaccine (179970.83 ± 66773.73/cumm) . The difference in deferral rates between the two groups was remarkable (34.7% vs. 0.9%, with the p-value < 0.001). CONCLUSION: Vaccination certainly increased the deferral rates of plateletpheresis donors due to low platelet counts. Average platelet counts were low in fully vaccinated individuals, however, the platelets returned to normal counts as the post-vaccination days progressed.

9.
Asian J Transfus Sci ; 17(1): 63-68, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37188022

RESUMEN

PURPOSE: Assessment of residual white blood cell (rWBC) count is vital to ascertain the quality of leukodepleted (LD) blood components. Automated cell analyzers lack the sensitivity for the assessment of very few leukocytes as found in LD blood components. Flow Cytometry (FC) based methods and Nageotte hemocytometer are the most commonly used techniques for this purpose. The objective of this study was to compare the use of Nageotte hemocytometer and FC for quality control of LD red blood cell units. MATERIALS AND METHODS: A prospective, observational study was conducted in the Department of Immunohematology and Blood Transfusion of a tertiary care center from September 2018 to September 2020. About 303 LD-packed red blood cell units were tested by FC and Nageotte hemocytometer for rWBCs. RESULTS: The number of rWBC (mean) detected by flow cytometer and Nageotte's hemocytometer was 1.06 ± 0.43 white blood cell (WBC)/µL and 0.67 ± 0.39 WBC/µL, respectively. Coefficient of variation was 58.37% by Nageotte hemocytometer method and 40.46% by FC. Linear regression analysis did not show any correlation (R2= 0.098, P = 0.001) whereas Pearson's correlation coefficient showed a weak relation (r = 0.31) between the two methods. CONCLUSION: Flow cytometric technique provides a more precise and accurate objective tool compared to Nageotte hemocytometer which is labor intensive, time consuming, and prone to errors arising out of subjectivity along with reported underestimation bias. In the absence of adequate infrastructure, resources, and trained workforce, Nageotte hemocytometer method is a reliable alternative. Nageotte's chamber could be best used in the resource-constrained setup as it offers a relatively inexpensive, simple, and viable means to enumerate rWBCs.

10.
Asian J Transfus Sci ; 17(2): 202-209, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-38274976

RESUMEN

BACKGROUND: Hematopoietic stem cell transplantation (HSCT) has emerged as a curative measure for life-threatening hematological disorders. It can be autologous or allogeneic depending on the disease characteristics. Providing transfusion support to the transplant patients can be challenging, especially in AB-mismatched allogeneic HSCT. In this study, we investigated the impact of ABO incompatibility in patients undergoing allogeneic HSCT. MATERIALS AND METHODS: A retrospective review was conducted in 76 patients with hematological diseases who underwent allogeneic HSCT. Transfusion requirements, engraftment profile, incidence of graft versus host disease (GvHD), and mortality for a period of 1 year were analyzed. RESULTS: ABO incompatibility between donor and the patient did not significantly affect the neutrophil and platelet (PLT) engraftment time (P = 0.389, 0.349, respectively), packed red blood cells transfusion requirement, and duration of initial hospital stay. However, patients of ABO-incompatible HSCT received more PLT transfusions posttransplant which was statistically significant. 29.1% of ABO compatible and 16.7% incompatible HSCT patients developed GVHD. Mortality rates in the two groups were 16.7% and 8.3%, respectively. However, differences in both the parameters were not statistically significant. CONCLUSION: Our study showed that ABO incompatibility does not significantly affect the outcome and should not be a limiting factor for selection of donor. Donor availability and human leukocyte antigen (HLA) matching remain the critical selection criteria.

11.
Indian J Pathol Microbiol ; 65(1): 195-197, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35074995

RESUMEN

Myelodysplastic syndromes (MDSs) are clonal hematopoietic stem cell neoplasms characterized by bone marrow failure leading to ineffective hematopoiesis, dyspoiesis, and cytopenias with a risk of progression to acute leukemia. Immunological syndromes have been reported to occur along with MDS in literature. However, cold autoimmune hemolytic anemia (AIHA) has rarely been reported in association with MDS. Herein, we report a case of an elderly male who presented with fever and cytopenias. He was being treated as a case of megaloblastic anemia in the past with no response to therapy. At present admission, the peripheral blood smear examination revealed red cell agglutination, thrombocytopenia with 4% blasts. Cold agglutinin disease was confirmed by a thermal agglutination test and bone marrow evaluation showed adequate megakaryocytes with 10% blasts; consistent with the diagnosis of MDS with excess blasts (MDS-EB2). Cytogenetic studies revealed multiple abnormalities. This report is being discussed in view of its rarity of presentation of cold AIHA with MDS.


Asunto(s)
Anemia Hemolítica Autoinmune/complicaciones , Anemia Hemolítica Autoinmune/diagnóstico , Síndromes Mielodisplásicos/diagnóstico , Anciano , Biopsia , Médula Ósea/patología , Humanos , Inmunohistoquímica , Leucemia Mieloide Aguda/complicaciones , Masculino , Síndromes Mielodisplásicos/patología
12.
J Supercomput ; 78(13): 14813-14845, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35431450

RESUMEN

In this work, we propose a multi-tier architectural model to separate functionality and security concerns for distributed cyber-physical systems. On the line of distributed computing, such systems require the identification of leaders for distribution of work, aggregation of results, etc. Further, we propose a fault-tolerant leader election algorithm that can independently elect the functionality and security leaders. The proposed election algorithm identifies a list of potential leader capable nodes to reduce the leader election overhead. It keeps identifying the highest potential node as the leader, whenever needed, including the situation when one has failed. We also explain the proposed architecture and its management method through a case study. Further, we perform several experiments to evaluate the system performance. The experimental results show that the proposed architectural model improves the system performance in terms of latency, average response time, and the number of real-time tasks completed within the deadline.

13.
Asian J Transfus Sci ; 16(2): 251-256, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36687532

RESUMEN

BACKGROUND: Most of the red blood cell (RBC) storage lesions can be attributed to oxidative stress encountered by the RBCs throughout the duration of their storage. Various donor variables at the time of donation may be responsible for the total antioxidant capacity of the supernatant and thus, the "storability" and the magnitude of development of these RBC storage lesions. It is known that uric acid (UA) is responsible for more than 60% of the TAC of the blood. This study aims to explore the relationship between donor UA levels and the difference in percentage hemolysis, an important RBC storage lesion, on day 1 and day 21, in stored packed RBCs (PRBCs) units. MATERIALS AND METHODS: The serum UA of 100 healthy voluntary male blood donors was estimated at the time of blood donation. The percentage hemolysis in the supernatant of the leukoreduced citrate phosphate dextrose/saline-adenine-glucose-mannitol RBC units (n = 100) prepared from these donors was calculated on day 1 and day 21. The difference in percentage hemolysis between donors with high normal serum UA levels (>7 mg/dL) was compared to that of the donors with low normal serum UA levels (<5 mg/dL) to observe the effect of donor UA levels on the difference in percentage hemolysis. RESULTS: The mean of the differences in percentage hemolysis in the supernatant in low UA group (<5 mg/dL) was higher than the mean of the differences in percentage hemolysis in the supernatant in high UA group (>7 mg/dL) and this was statistically significant (P < 0.001). The donor serum UA level and difference in percentage hemolysis on day 21 and day 1 were found to be negatively co-related. CONCLUSION: Higher levels of serum UA of blood donors seem to have a protective effect on the stored PRBC units as shown in this study. Hence, the potential of UA as one of the constituents of RBC additive solutions might lead to the enhancement of the quality of stored PRBC units by decreasing the RBC storage lesions.

14.
Asian J Transfus Sci ; 15(2): 146-150, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34908745

RESUMEN

BACKGROUND: Cryoprecipitate helps in replenishing important coagulation factors like fibrinogen, Factor VIII and von Willebrand factor without running the risk of volume overload. It is very useful in the treatment of trauma patients with active bleeding and works best when administered early. Extending the shelf life of thawed cryoprecipitate beyond 4 hours enables us to manage inventory better, reduces the burden of demand vs supply as well as minimizes wastage. It can also help in logistically supporting the transfusion services in making cryoprecipitate readily available in mass casualty scenarios (war, natural calamity) in remote locations by reducing the time required for thawing cryoprecipitate and the need for costly storage equipment. AIM: The aim of this study was to compare the levels of Factor VIII, Fibrinogen and von Willebrand factor on thawed cryoprecipitate after prolonged storage for 5 days at a temperature of 2-6°C. METHODOLOGY: The above mentioned coagulation factors were analyzed in cryoprecipitate at the time of product thaw and again after 120 hours of 2 to 6°C storage using fully automated coagulation analyser (STA Compact Max). All parameters were expressed as Mean ± Standard deviation and were analyzed using paired t-test with level of significance, P < 0.05. RESULTS: There was a significant decrease in the level of Factor VIII, whereas the levels of fibrinogen and von Willebrand Factor remained stable during the storage period. All the cryoprecipitate units retained factor activities above therapeutic range even after 5 days of storage at 2-6°C. CONCLUSION: Although the levels of clotting factors are reduced during storage, they are still maintained above the therapeutic range. In scenarios where maintaining frozen cryoprecipitate inventory is a logistical challenge and emergency massive demands of cryoprecipitate are foreseen, the use of pre-thawed cryoprecipitate can be considered as a viable option.

15.
Lab Med ; 51(4): 362-369, 2020 Jul 08.
Artículo en Inglés | MEDLINE | ID: mdl-31758694

RESUMEN

BACKGROUND: Donor factors have a variable correlation with cluster of differentiation (CD)34+ cell dose in allogeneic peripheral blood stem cell (PBSC) harvests. CD34+ cell dose affects the speed of hematopoietic recovery and percentage of donor chimerism in the recipient. METHODS: A total of 25 allogeneic PBSC transplants performed during a 3-year period were included. All donors underwent mobilization with filgrastim. Leukapheresis, flowcytometric CD34+ cell enumeration, and chimerism analysis were performed and correlated with recipient outcome. RESULTS: Besides age, all other donor parameters had a positive correlation with CD34+ cell count. Engraftment kinetics and chimerism had a positive correlation with the CD34+ yield of the PBSC product. Acute graft-vs-host disease (GVHD) was observed in patients with complete chimerism at day 30 after transplantation. CONCLUSION: Adequate CD34+ cell yield happens in healthy donors, independent of donor demographic patterns with G-CSF only. A diverse population of donors can thus be approached for Matched Unrelated Donor (MUD) transplants. An accurate quantitative analysis of early donor chimerism in the recipient (at day 30) is an excellent tool for post-transplant monitoring for acute GvHD.


Asunto(s)
Donantes de Sangre/estadística & datos numéricos , Enfermedad Injerto contra Huésped/epidemiología , Trasplante de Células Madre de Sangre Periférica/efectos adversos , Factores de Edad , Antígenos CD34/genética , Antígenos CD34/metabolismo , Filgrastim/farmacología , Factor Estimulante de Colonias de Granulocitos/metabolismo , Fármacos Hematológicos/farmacología , Humanos , Trasplante de Células Madre de Sangre Periférica/métodos , Trasplante de Células Madre de Sangre Periférica/estadística & datos numéricos , Células Madre de Sangre Periférica/efectos de los fármacos , Células Madre de Sangre Periférica/metabolismo , Trasplante Homólogo
16.
J Nanosci Nanotechnol ; 9(8): 4948-60, 2009 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-19928173

RESUMEN

Use of correlation function and interface distribution function to obtain the morphological parameters from Small Angle X-ray Scattering data makes it as an important quantitative method to evaluate lamellar morphology. Analysis using correlation function assumes lamellar stack morphology with variation of electron density along one dimension where lateral width of lamellae is much larger than the long period normal to the lamellae and the electron density varies with a rectangular profile for alternating crystalline and amorphous layers. In this work, a modified Porod law approach is used for the deviation from ideal two phase model and the thickness of transition zone with variation in electron densities is calculated. Morphological parameters of various grades of organically modified Polypropylene clay nanocomposites, such as long period, linear crystallinity, lamellar thickness and amorphous thickness are estimated using a combination of correlation and interface distribution function. Presence of transition zones does not influence the values for amorphous layer thickness, crystalline layer thickness and long period. Variations in values of long period calculated from correlation and interface function suggest a distribution of lamellar sizes in the polymer and nanocomposites. A new model consisting of the integrated correlation function of polymer and organoclay was developed to quantify the extent of exfoliation of organoclay in the nanocomposites by introducing a parameter, the exfoliation factor, beta. For a highly non-exfoliated system, the large number of clay tactoids is highly correlated and interacting, the correlation function of nanocomposites will be similar to that of nanoclay samples with low values of exfoliation factor. The correlation function of well exfoliated nanocomposites is similar to neat polymer, and such systems have high values of the exfoliation factor. Moreover, the exfoliation factor, which is easily determined by a scattering experiment, correlated well to the important engineering properties of the nanocomposites.

17.
Mater Sci Eng C Mater Biol Appl ; 105: 109982, 2019 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-31546427

RESUMEN

Titanium and its alloys especially Ti6Al4V have long been used in biomedical implants. Although, Ti6Al4V is biocompatible, yet there has been consistent effort to improve its osteoconductive and osteogenic property to enhance the implant performance. In this regard, surface modification of Ti6Al4V implants with TiO2 nanotubes and subsequent application of biopolymeric coating has started emerging as a promising approach. Keeping this perspective in mind, here we have coated nano TiO2 modified Ti6Al4V surface with silk fibroin isolated from B. mori cocoons. The coating of silk fibroin was done on the implant using electrophoretic deposition technique at three different voltages. Topography analysis by AFM confirms the uniform coating of silk fibroin. A variation in contact angle from 89.7 ±â€¯2° to 83.6 ±â€¯2° was observed when tested for wettability using drop shape analyzer. The biocompatibility studies showed SF coated substrates support the adhesion of both MG63 bone cells and human mesenchymal stem cells (hMSCs). The formation of peripheral vinculin complexes on SF surface confirmed the adhesion through focal adhesion points. Consequently, SF coating improved the cellular expression of alkaline phosphatase by 1.1 times compared to the polished Ti6Al4V surface (PTi64). Increased expression of late osteogenic markers osterix and osteocalcin was also observed in hMSCs cultured on SF coated nanotubular surface compared to PTi64. These results together implied that coating of silk fibroin on TiO2 modified Ti6Al4V surface improve the osteogenic potential of the implant.


Asunto(s)
Huesos/efectos de los fármacos , Materiales Biocompatibles Revestidos/farmacología , Fibroínas/farmacología , Nanotubos/química , Osteogénesis/efectos de los fármacos , Prótesis e Implantes , Titanio/farmacología , Actinas/metabolismo , Fosfatasa Alcalina/metabolismo , Aleaciones , Animales , Bombyx , Calcificación Fisiológica/efectos de los fármacos , Adhesión Celular/efectos de los fármacos , Diferenciación Celular/efectos de los fármacos , Línea Celular , Proliferación Celular/efectos de los fármacos , Forma de la Célula/efectos de los fármacos , Humanos , Células Madre Mesenquimatosas/efectos de los fármacos , Células Madre Mesenquimatosas/metabolismo , Nanotubos/ultraestructura , Osteocalcina/metabolismo , Espectroscopía Infrarroja por Transformada de Fourier , Vinculina/metabolismo , Humectabilidad
18.
Ambio ; 48(2): 192-212, 2019 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-29855893

RESUMEN

The impacts of climate change are of particular concern to the coastal region of tropical countries like India, which are exposed to cyclones, floods, tsunami, seawater intrusion, etc. Climate-change adaptation presupposes comprehensive assessment of vulnerability status. Studies so far relied either on remote sensing-based spatial mapping of physical vulnerability or on certain socio-economic aspects with limited scope for upscaling or replication. The current study is an attempt to develop a holistic and robust framework to assess the vulnerability of coastal India at different levels. We propose and estimate cumulative vulnerability index (CVI) as a function of exposure, sensitivity and adaptive capacity, at the village level, using nationally comparable and credible datasets. The exposure index (EI) was determined at the village level by decomposing the spatial multi-hazard maps, while sensitivity (SI) and adaptive capacity indices (ACI) were estimated using 23 indicators, covering social and economic aspects. The indicators were identified through the literature review, expert consultations, opinion survey, and were further validated through statistical tests. The socio-economic vulnerability index (SEVI) was constructed as a function of sensitivity and adaptive capacity for planning grassroot-level interventions and adaptation strategies. The framework was piloted in Sindhudurg, a coastal district in Maharashtra, India. It comprises 317 villages, spread across three taluks viz., Devgad, Malvan and Vengurla. The villages in Sindhudurg were ranked based on this multi-criteria approach. Based on CVI values, 92 villages (30%) in Sindhudurg were identified as highly vulnerable. We propose a decision tool for identifying villages vulnerable to changing climate, based on their level of sensitivity and adaptive capacity in a two-dimensional matrix, thus aiding in planning location-specific interventions. Here, vulnerability indicators are classified and designated as 'drivers' (indicators with significantly high values and intervention priority) and 'buffers' (indicators with low-to-moderate values) at the village level. The framework provides for aggregation or decomposition of CVI and other sub-indices, in order to plan spatial contingency plans and enable swift action for climate adaptation.


Asunto(s)
Cambio Climático , Tormentas Ciclónicas , Toma de Decisiones , Inundaciones , India
19.
Regen Med ; 13(5): 545-558, 2018 07 01.
Artículo en Inglés | MEDLINE | ID: mdl-30124377

RESUMEN

AIM: Cartilage damage is a common age-related problem that leads to progressive proteoglycan loss. Glucosamine stimulates proteoglycan synthesis and, therefore, its effect on the cartilage extracellular matrix synthesis over silk fibroin:chitosan (SF:CS) tissue-engineered scaffold was investigated for cartilage construct generation. MATERIALS & METHODS: Human mesenchymal stem cells (hMSCs) were cultured and differentiated over SF:CS-glucosamine porous scaffold, under dynamic culture condition in spinner flask bioreactor. RESULTS: hMSCs-seeded scaffold in dynamic culture exhibited homogenous cell distribution, proliferation and higher cell density at the core than static culture. Glucosamine in scaffold promoted proteoglycan and collagenous matrix synthesis as revealed by histological and immunofluorescence studies. Quantitative-PCR analysis showed upregulation of cartilage-specific genes, thereby confirming the chondrogenic differentiation. CONCLUSION: The chondrogenic differentiation of hMSCs was enhanced by the synergistic effect of glucosamine incorporated in SF:CS scaffold and influence of 3D dynamic culture environment, thereby resulting in chondrogenic phenotype of the cells that promoted cartilage regeneration.


Asunto(s)
Diferenciación Celular , Quitosano/química , Condrogénesis , Fibroínas/química , Glucosamina/química , Células Madre Mesenquimatosas/metabolismo , Andamios del Tejido/química , Técnicas de Cultivo de Célula/métodos , Humanos , Células Madre Mesenquimatosas/citología
20.
J Biomed Mater Res A ; 106(2): 397-407, 2018 02.
Artículo en Inglés | MEDLINE | ID: mdl-28960800

RESUMEN

Cartilage construct generation includes a scaffold with appropriate composition to mimic matrix of the damaged tissue on which the stem cells grow and differentiate. In this study, umbilical cord blood (UCB) derived human mesenchymal stem cells (hMSCs) were seeded on freeze dried porous silk-fibroin (SF)/chitosan (CS) scaffolds. Influence of static and dynamic (spinner flask bioreactor) culture conditions on the developing cartilage construct were studied by in-vitro characterization for viability, proliferation, distribution, and chondrogenic differentiation of hMSCs over the scaffold. Constructs developed in spinner flask consisted of 62% live cells, and exhibited 543% more cell density at the core than constructs cultured in static system. Quantification of DNA and glycosaminoglycans accumulation after 21 days showed the progression of chondrogenic differentiation of hMSCs was higher in dynamic culture compared to static one. In constructs generated under dynamic condition, histology staining for proteoglycan matrix, and fluorescence staining for collagen-II and aggrecan showed positive correlation between early and late stage chondrogenic markers, which was further confirmed by quantitative PCR analysis, showing low collagen-I expression and highly expressed Sox9, collagen-II and aggrecan. The present study demonstrated that construct generated by combining 3D SF/CS scaffold with UCB-hMSCs under dynamic condition using spinner flask bioreactor can be used for cartilage tissue regeneration for future medical treatments. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 397-407, 2018.


Asunto(s)
Cartílago/fisiología , Técnicas de Cultivo de Célula/métodos , Sangre Fetal/citología , Fibroínas/farmacología , Células Madre Mesenquimatosas/citología , Andamios del Tejido/química , Animales , Bombyx , Adhesión Celular/efectos de los fármacos , Diferenciación Celular/efectos de los fármacos , Forma de la Célula/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Células Cultivadas , Condrocitos/efectos de los fármacos , Condrocitos/metabolismo , Condrogénesis/efectos de los fármacos , ADN/metabolismo , Fluorescencia , Glicosaminoglicanos/metabolismo , Humanos , Inmunofenotipificación , Células Madre Mesenquimatosas/efectos de los fármacos , Células Madre Mesenquimatosas/ultraestructura , Porosidad
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