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1.
J Radiol Prot ; 43(4)2023 10 25.
Artigo em Inglês | MEDLINE | ID: mdl-37797608

RESUMO

A method has been developed for solving the Fredholm equation in the barrier geometry for reconstructing the surface activity density (SAD) from the results of measuring the ambient dose equivalent rate (ADER). Inclusion of the barrier geometry means that the method takes into account the shielding effect of buildings and structures on the contaminated site. The method was based on the representation of the industrial site, buildings and radiation fields in the form of a raster and the use of the visibility matrix (VM) of raster cells to describe the barrier geometry. The developed method was applied to a hypothetical industrial site with a size of 200 × 200 conventional units for four types of SAD distribution over the surface of the industrial site: 'fragmentation', 'diffuse', 'uniform' and 'random'. The method of Lorentz curves was applied to estimate the compactness of the distributions of SAD and the ADER for the considered radiation sources. It was shown that the difference between the Lorentz curve for SAD and ADER means that the determination of the spatial distribution of SAD over the industrial site by solving the integral equation is essentially useful for determining the location of radiation source locations on the industrial site. The accuracy of SAD reconstruction depends on the following parameters: resolution (fragmentation) of the raster, the height of the radiation detector above the scanned surface, and the angular aperture of the radiation detector. The measurement of ADER is simpler and quicker than the direct measurement of SAD and its distribution. This represents a significant advantage if SAD distribution needs to be determined in areas with high radiation dose-rate during limited time. The developed method is useful for supporting radiation monitoring and optimizing the remediation of nuclear legacies, as well as during the recovery phase after a major accident.


Assuntos
Monitoramento de Radiação , Radioisótopos , Monitoramento de Radiação/métodos
2.
J Radiol Prot ; 43(4)2023 10 25.
Artigo em Inglês | MEDLINE | ID: mdl-37797613

RESUMO

A method for reconstructing surface activity density (SAD) maps based on the solution of the Fredholm equation has been developed and applied. The construction of SAD maps was carried out for the site of the temporary storage (STS) of spent fuel and radioactive waste (RW) in Andreeva Bay using the results of measuring campaign in 2001-2002 and for the sheltering construction of the solid RW using the results of measurements in 2021. The Fredholm equation was solved in two versions: under conditions of a barrier-free environment and taking into account buildings and structures located on the industrial site of the STS Andreeva Bay. Lorenz curves were generated to assess the compactness of the distributions of SAD and ambient dose equivalent rate (ADER) for the industrial site and the sheltering construction at STS Andreeva Bay, the area of the IV stage uranium tailing site near the city of Istiklol in the Republic of Tajikistan, and for roofs of the Chernobyl nuclear power plant. The nature of impact of the resolution (fragmentation) of the raster, the value of the radius of mutual influence of points (contamination sites), the height of the radiation detector above the scanned surface and the angular aperture of the radiation detector on the accuracy of the SAD reconstruction is shown. The method developed allows more accurate planning of decontamination work when only ADER measurements data is available. The proposed method can be applied to support the process of decontamination of radioactively contaminated territories, in particular during the remediation of the STS Andreeva Bay.


Assuntos
Acidente Nuclear de Chernobyl , Monitoramento de Radiação , Resíduos Radioativos , Baías , Monitoramento de Radiação/métodos , Resíduos Radioativos/análise , Radioisótopos
3.
J Radiol Prot ; 43(3)2023 08 24.
Artigo em Inglês | MEDLINE | ID: mdl-37489839

RESUMO

In the 1960s, a shore technical base (STB) was established at Andreeva Bay on the Kola Peninsula, in northwest Russia. The STB maintained nuclear submarines and the nuclear icebreaker fleet, receiving and storing fresh and spent nuclear fuel (SNF) as well as solid and liquid radioactive waste (RW). It was subsequently re-designated as a site for temporary storage (STS) for SNF and RW. Over time, the SNF storage facilities partly lost their containment functions, leading to radioactive contamination of workshops and the site above permitted values. The technological and engineering infrastructure at the site was also significantly degraded as well as the condition of the stored SNF. At present, the STS Andreeva Bay facility is under decommissioning. This paper describes progress with the creation of safe working measures for workers involved in site remediation and SNF recovery operations, including the determination of safe shift times in high radiation areas, as part of overall optimization of safety. Results are presented for the successful application of these measures in the period 2019-2021, during which time significant SNF recovery and removal operations were completed without incident. Significant important experience has been gained to support safe removal of remaining SNF, including the most hazardous degraded fuel, as well as recovery of other higher level RW and decommissioning of the old storage buildings and structures.


Assuntos
Monitoramento de Radiação , Resíduos Radioativos , Humanos , Baías , Monitoramento de Radiação/métodos , Resíduos Radioativos/análise , Reatores Nucleares , Federação Russa
4.
J Radiol Prot ; 42(2)2022 04 26.
Artigo em Inglês | MEDLINE | ID: mdl-35467550

RESUMO

The International Atomic Energy Agency has coordinated an international project addressing enhancements of methods for modelling the biosphere in post-closure safety assessments of solid radioactive waste disposal. This has resulted in the enhanced BIOMASS methodology that is described elsewhere in this special issue. To a large degree, the enhancements to the BIOMASS methodology arose from experience gained in applying the original methodology, both in the context of other international projects and in assessments of existing or proposed disposal facilities for solid radioactive wastes. Here, this experience is used, together with information on the status of solid radioactive waste disposal programmes worldwide, to identify opportunities for applying the enhanced methodology and for learning from those applications. This provides a basis for identifying research and development to support application of the enhanced methodology in a variety of environmental settings. These research and development requirements include aspects related to climate change under a variety of forcing scenarios, landform development in climatic regimes ranging from cold, polar to arid, tropical, modelling of groundwater flow and contaminant transport in surface-water catchments where both fractured rock and porous sediments are present, and studies of the transport of key radioisotopes of elements central to major biogeochemical cycles, such as those of carbon, chlorine, sulphur and iodine. In addition, some remarks are made on aspects of the application of the enhanced methodology that could imply review and updating of regulations and regulatory guidance, e.g. in relation to the definition of representative persons or groups to be considered in assessments and in respect of approaches to the assessment of radiological impacts on non-human biota. Furthermore, consideration is given as to how the scientific and technical experience that has been gained and methods that have been developed in the context of solid radioactive disposal facilities could support management of contaminated sites and legacy facilities that are likely to require long-term management and stewardship.


Assuntos
Resíduos Radioativos , Radioatividade , Eliminação de Resíduos , Biomassa , Resíduos Radioativos/análise , Pesquisa
5.
J Radiol Prot ; 40(2): 410-430, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-31968313

RESUMO

This paper deals with classification of dose distributions of nuclear workers based on antikurtosis (Q) and entropy coefficients (K) and their relationship presented in QK-diagrams. It is shown that determination of the most appropriate distribution to adopt, for a specific data set of a wide range of input data, requires building and analysing QK-diagrams for distributions of logarithms of individual doses. Actual dose distributions for emergency and occupational exposure situations were then considered, as well as doses for one day of work during clean-up and routine activities. It is shown that, in all cases, three types of distributions of logarithms of individual doses were present: normal, Weibull and Chapeau. The location of the representation point of a dose distribution reflects the degree of dose control of the group of workers whose individual doses are collectively displayed in the QK-diagram. The more the representation point of the analysed distribution of the logarithms of the individual dose of a given contingent of workers deviates from the point of the lognormal distribution, the more there was intervention in the process of individual dose accumulation. Thus, QK-diagrams could be used to develop a dose control function. It is shown that the hybrid lognormal distribution, which is widely used in the field of radiation safety, for the purpose of approximation of real dose distributions, is unable to satisfactorily describe many dose distributions arising in aftermath operations and occupational exposure.


Assuntos
Exposição Ocupacional/classificação , Exposição Ocupacional/prevenção & controle , Doses de Radiação , Liberação Nociva de Radioativos/classificação , Humanos , Método de Monte Carlo , Doenças Profissionais/prevenção & controle , Lesões por Radiação/prevenção & controle , Monitoramento de Radiação , Federação Russa
6.
J Radiol Prot ; 38(2): 480-509, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29388554

RESUMO

The Coastal Technical Base (CTB) №569 at Andreeva Bay was established in the early 1960s and intended for the refueling of nuclear submarine reactors and temporary storage of spent nuclear fuel (SNF) and radioactive waste (RW). In 2001, the base was transferred to the Russian Ministry for Atomic Energy and the site remediation began. The paper describes in detail the radiation situation change at the technical site in Andreeva Bay from 2002-2016, the period of preparation for the most critical phase of remedial work: removal of spent fuel assemblies. The analysis of aggregated indicators and data mining were used. The article suggests the best number and location of checkpoints needed to ensure sufficient accuracy of the radiation situation description. The fractal properties of the radiation field are studied using the Hurst index. The relationship between checkpoints was assessed using the method of searching for checkpoint communities. The decrease in the integral of the ambient dose equivalent rate (ADER) at the technical site was evaluated by the method of time series decomposition. Three components of time series were identified: trend, seasonal and residual. The trend of the ADER integral over the technical site is a monotonic decreasing function, where the initial and final values differ tenfold. Taking into account that 137Cs dominates the radiation situation on-site, it is clear that the ADER due to the radionuclide decay will have decreased by 1.4 times. It is estimated that only a small proportion of 137Cs has migrated off-site. Therefore, approximately a sevenfold decrease in dose rate is mainly due to remediation activities of personnel. During the year, the seasonal component varies the ADER integral by a factor of two, due to snowfall. The residual component reflects the uncertainty of the ADER integral calculation and phases of active SNF and RW management. The methods developed are used to support the optimization of remediation work as well as regulatory supervision of occupational radiation protection.


Assuntos
Centrais Nucleares/normas , Reatores Nucleares , Doses de Radiação , Resíduos Radioativos , Federação Russa , Fatores de Tempo
7.
J Radiol Prot ; 37(3): 697-714, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28657905

RESUMO

Radiation doses received by workers during their movement within areas contaminated as a result of events and activities, leading to emergency or existing exposure situations, may provide a substantial contribution to total external exposure during remediation work. This paper describes an approach to minimise worker external exposure in these circumstances, based on graph theory. The paper describes several tasks, including: searching for a route with the lowest dose, searching for an optimal bypass with a given set of control points and searching for the optimal road network coverage. Classical graph theory algorithms have been used (Dijkstra's algorithm, Chinese postman problem and travelling salesman problem). Algorithms for solving the above mentioned problems have been developed and were included in the information-analytical system for radiation safety. This software has been applied for optimisation of protection during remediation work at the Andreeva Bay site of temporary storage for spent fuel and radioactive waste in the Kola Peninsula, both in the context of existing exposure situations and improving the preparedness for emergency exposure situations.


Assuntos
Exposição Ocupacional/prevenção & controle , Doses de Radiação , Monitoramento de Radiação/métodos , Proteção Radiológica/métodos , Gestão da Segurança/métodos , Algoritmos , Humanos , Resíduos Radioativos , Software
9.
Bone Joint J ; 98-B(5): 634-40, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-27143734

RESUMO

AIMS: Few reports compare the contribution of the talonavicular articulation to overall range of movement in the sagittal plane after total ankle arthroplasty (TAA) and tibiotalar arthrodesis. The purpose of this study was to assess changes in ROM and functional outcomes following tibiotalar arthrodesis and TAA. PATIENTS AND METHODS: Patients who underwent isolated tibiotalar arthrodesis or TAA with greater than two-year follow-up were enrolled in the study. Overall arc of movement and talonavicular movement in the sagittal plane were assessed with weight-bearing lateral maximum dorsiflexion and plantarflexion radiographs. All patients completed Short Form-12 version 2.0 questionnaires, visual analogue scale for pain (VAS) scores, and the Foot and Ankle Ability Measure (FAAM). RESULTS: In all, 41 patients who underwent TAA and 27 patients who underwent tibiotalar arthrodesis were enrolled in the study. The mean total arc of movement was 34.2° (17.0° to 59.1°) with an average contribution from the talonavicular joint of 10.5° (1.2° to 28.8°) in the TAA cohort. The average total arc of movement was 24.3° (6.9° to 44.3°) with a mean contribution from the talonavicular joint of 22.8° (5.6° to 41.4°) in the arthrodesis cohort. A statistically significant difference was detected for both total sagittal plane movement (p = 0.00025), and for talonavicular motion (p < 0.0001). A statistically significant lower VAS score (p = 0.0096) and higher FAAM (p = 0.01, p = 0.019, respectively) was also detected in the TAA group. CONCLUSION: TAA preserves more anatomical movement, has better pain relief and better patient-perceived post-operative function compared with patients undergoing fusion. The relative increase of talonavicular movement in fusion patients may play a role in the outcomes compared with TAA and may predispose these patients to degenerative changes over time. TAKE HOME MESSAGE: TAA preserves more anatomic sagittal plane motion and provides greater pain relief and better patient-perceived outcomes compared with ankle arthrodesis. Cite this article: Bone Joint J 2016;98-B:634-40.


Assuntos
Articulação do Tornozelo/cirurgia , Artrodese , Artroplastia de Substituição do Tornozelo , Amplitude de Movimento Articular/fisiologia , Adulto , Idoso , Articulação do Tornozelo/fisiopatologia , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Avaliação de Resultados da Assistência ao Paciente , Estudos Retrospectivos , Articulações Tarsianas/fisiologia , Escala Visual Analógica , Adulto Jovem
10.
Phys Chem Chem Phys ; 18(8): 5799-806, 2016 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-26426572

RESUMO

The bipedal spin label Rx is more restricted in its conformation and dynamics than its monopodal counterpart R1. To systematically investigate the utility of the Rx label, we have attempted to comprehensively survey the attachment of Rx to protein secondary structures. We have examined the formation, structure and dynamics of the spin label in relation to the underlying protein in order to determine feasibility and optimum conditions for distance and orientation measurement by pulsed EPR. The labeled proteins have been studied using molecular dynamics, CW EPR, pulsed EPR distance measurement at X-band and orientation measurement at W-band. The utility of different modes and positions of attachment have been compared and contrasted.


Assuntos
Espectroscopia de Ressonância de Spin Eletrônica , Proteínas/química , Marcadores de Spin , Simulação de Dinâmica Molecular
12.
J Radiol Prot ; 35(3): 571-96, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26160861

RESUMO

In compliance with the fundamentals of the government's policy in the field of nuclear and radiation safety approved by the President of the Russian Federation, Russia has developed a national program for decommissioning of its nuclear legacy. Under this program, the State Atomic Energy Corporation 'Rosatom' is carrying out remediation of a Site for Temporary Storage of spent nuclear fuel (SNF) and radioactive waste (RW) at Andreeva Bay located in Northwest Russia. The short term plan includes implementation of the most critical stage of remediation, which involves the recovery of SNF from what have historically been poorly maintained storage facilities. SNF and RW are stored in non-standard conditions in tanks designed in some cases for other purposes. It is planned to transport recovered SNF to PA 'Mayak' in the southern Urals. This article analyses the current state of the radiation safety supervision of workers and the public in terms of the regulatory preparedness to implement effective supervision of radiation safety during radiation-hazardous operations. It presents the results of long-term radiation monitoring, which serve as informative indicators of the effectiveness of the site remediation and describes the evolving radiation situation. The state of radiation protection and health care service support for emergency preparedness is characterized by the need to further study the issues of the regulator-operator interactions to prevent and mitigate consequences of a radiological accident at the facility. Having in mind the continuing intensification of practical management activities related to SNF and RW in the whole of northwest Russia, it is reasonable to coordinate the activities of the supervision bodies within a strategic master plan. Arrangements for this master plan are discussed, including a proposed programme of actions to enhance the regulatory supervision in order to support accelerated mitigation of threats related to the nuclear legacy in the area.


Assuntos
Reatores Nucleares/legislação & jurisprudência , Exposição Ocupacional/legislação & jurisprudência , Monitoramento de Radiação/legislação & jurisprudência , Proteção Radiológica/legislação & jurisprudência , Proteção Radiológica/métodos , Resíduos Radioativos/legislação & jurisprudência , Gerenciamento de Resíduos/legislação & jurisprudência , Gerenciamento de Resíduos/métodos , Regulamentação Governamental , Humanos , Resíduos Industriais/legislação & jurisprudência , Federação Russa , Gestão da Segurança/legislação & jurisprudência
13.
Placenta ; 36(7): 738-49, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25956987

RESUMO

INTRODUCTION: Plasmodium chabaudi AS-infection in pregnant A/J and C57BL/6J mice results in mid-gestational pregnancy loss. Although associated with increased systemic and placental pro-inflammatory responses and coagulopathy, the molecular mechanisms that underlie poor pregnancy outcomes in these mice are not yet fully understood. This study investigates the relationships between inflammation, apoptosis and malaria-induced pregnancy loss. METHODS: Infection with P. chabaudi AS in early murine pregnancy and term human placental tissues from an endemic setting were assessed by histology, immunohistochemistry, TUNEL staining, real-time PCR, flow cytometry, western blot, and ELISA. RESULTS: Quantitative PCR reveals accumulation of lymphocytes and monocytes and upregulation of chemokines that attract these cell types in malaria-exposed mid-gestational A/J conceptuses. Monocyte accumulation is confirmed by flow cytometry and placental immunohistochemistry. Concurrent with initiation of malaria-induced abortion, markers of apoptosis are evident in the junctional zone, but not the labyrinth, of A/J placentae. In contrast, mid-gestation conceptuses in infected C57BL/6J lack evidence for monocyte accumulation, exhibiting low or no in situ placental staining despite trophoblast immunoreactivity for the monokine, CCL2. Additionally, placental apoptosis is not consistently observed, and when evident, appears after malaria-induced abortion typically initiates. Similarly, trophoblast apoptosis in term human placental malaria is not observed. Of those studied, a sole common feature of malaria-induced abortion in A/J and C57BL/6J mice is elevation of plasma tumor necrosis factor. DISCUSSION: Consistent with our previous observations, tumor necrosis factor is likely to be a central driver of malaria-induced pregnancy loss in both strains, but likely operates through mechanisms distinct from placental apoptosis in C57BL/6J mice.


Assuntos
Aborto Espontâneo/parasitologia , Apoptose/fisiologia , Inflamação/complicações , Malária/complicações , Plasmodium chabaudi , Complicações Parasitárias na Gravidez/fisiopatologia , Animais , Quimiocina CCL2/sangue , Quimiocinas/análise , Feminino , Idade Gestacional , Humanos , Imuno-Histoquímica , Inflamação/patologia , Inflamação/fisiopatologia , Leucócitos/patologia , Linfócitos/patologia , Camundongos , Camundongos Endogâmicos A , Camundongos Endogâmicos C57BL , Monócitos/patologia , Placenta/química , Placenta/parasitologia , Placenta/patologia , Gravidez , Complicações Parasitárias na Gravidez/patologia , Trofoblastos/patologia , Fator de Necrose Tumoral alfa/análise , Fator de Necrose Tumoral alfa/sangue
14.
J Radiol Prot ; 34(4): 755-73, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25254659

RESUMO

Andreeva Bay in northwest Russia hosts one of the former coastal technical bases of the Northern Fleet. Currently, this base is designated as the Andreeva Bay branch of Northwest Center for Radioactive Waste Management (SevRAO) and is a site of temporary storage (STS) for spent nuclear fuel (SNF) and other radiological waste generated during the operation and decommissioning of nuclear submarines and ships. According to an integrated expert evaluation, this site is the most dangerous nuclear facility in northwest Russia. Environmental rehabilitation of the site is currently in progress and is supported by strong international collaboration. This paper describes how the optimization principle (ALARA) has been adopted during the planning of remediation work at the Andreeva Bay STS and how Russian-Norwegian collaboration greatly contributed to ensuring the development and maintenance of a high level safety culture during this process. More specifically, this paper describes how integration of a system, specifically designed for improving the radiological safety of workers during the remediation work at Andreeva Bay, was developed in Russia. It also outlines the 3D radiological simulation and virtual reality based systems developed in Norway that have greatly facilitated effective implementation of the ALARA principle, through supporting radiological characterisation, work planning and optimization, decision making, communication between teams and with the authorities and training of field operators.


Assuntos
Locais de Resíduos Perigosos , Imageamento Tridimensional/métodos , Modelos Organizacionais , Cultura Organizacional , Proteção Radiológica/métodos , Resíduos Radioativos/prevenção & controle , Gestão da Segurança/organização & administração , Descontaminação/métodos , Noruega , Monitoramento de Radiação/métodos , Federação Russa
15.
Neuroscience ; 272: 76-87, 2014 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-24797326

RESUMO

Successful regeneration after injury requires either the direct reformation of the circuit or the formation of a bridge circuit to provide partial functional return through a more indirect route. Presently, little is known about the specificity of how regenerating axons reconnect or reconstruct functional circuits. We have established an in vivo Dorsal root entry zone (DREZ) model, which in the presence of Nerve Growth Factor (NGF), shows very robust regeneration of peptidergic nociceptive axons, but not other sensory axons. Expression of NGF in normal, non-injured animals leads to robust sprouting of only the peptidergic nociceptive axons. Interestingly, NGF-induced sprouting of these axons leads to severe chronic pain, whereas, regeneration leads to protective-like pain without chronic pain. Using this model we set out to compare differences in behavioral outcomes and circuit features between these two groups. In this study, we examined pre-synaptic and post-synaptic markers to evaluate the relationship between synaptic connections and behavioral responses. NGF-induced sprouting of calcitonin gene-related peptide (CGRP) axons resulted in a significant redistribution of synapses and cFos expression into the deeper dorsal horn. Regeneration of only the CGRP axons showed a general reduction in synapses and cFos expression within laminae I and II; however, inflammation of the hindpaw induced peripheral sensitization. These data show that although NGF-induced sprouting of peptidergic axons induces robust chronic pain and cFos expression throughout the entire dorsal horn, regeneration of the same axons resulted in normal protective pain with a synaptic and cFos distribution similar, albeit significantly less than that shown by the sprouting of CGRP axons.


Assuntos
Axônios/metabolismo , Fator de Crescimento Neural/metabolismo , Regeneração Nervosa/fisiologia , Plasticidade Neuronal/fisiologia , Nociceptores/metabolismo , Medula Espinal/metabolismo , Animais , Feminino , Dor/metabolismo , Ratos Sprague-Dawley , Traumatismos da Medula Espinal/metabolismo
16.
J Environ Radioact ; 131: 89-109, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-24238917

RESUMO

Decisions on permitting, controlling and monitoring releases of radioactivity into the environment rely on a great variety of factors. Important among these is the prospective assessment of radionuclide behavior in the environment, including migration and accumulation among and within specific environmental media, and the resulting environmental and human health impacts. Models and techniques to undertake such assessments have been developed over several decades based on knowledge of the ecosystems involved, as well as monitoring of previous radionuclide releases to the environment, laboratory experiments and other related research. This paper presents developments in the assessment of radiation doses and related research for some of the key radionuclides identified as of potential significance in the context of releases to the biosphere from disposal facilities for solid radioactive waste. Since releases to the biosphere from disposal facilities involve transfers from the geosphere to the biosphere, an important aspect is the combined effects of surface hydrology, near-surface hydrogeology and chemical gradients on speciation and radionuclide mobility in the zone in which the geosphere and biosphere overlap (herein described as the geosphere-biosphere subsystem). In turn, these aspects of the environment can be modified as a result of environmental change over the thousands of years that have to be considered in radioactive waste disposal safety assessments. Building on the experience from improved understanding of the behavior of the key radionuclides, this paper proceeds to describe development of a generic methodology for representing the processes and environmental changes that are characteristic of the interface between the geosphere and the biosphere. The information that is provided and the methodology that is described are based on international collaborative work implemented through the BIOPROTA forum, www.bioprota.org.


Assuntos
Meio Ambiente , Resíduos Radioativos , Instalações de Eliminação de Resíduos , Fenômenos Geológicos , Radioisótopos
17.
Exp Neurol ; 250: 156-64, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24099728

RESUMO

Different experimental and clinical strategies have been used to promote survival of transplanted embryonic ventral mesencephalic (VM) neurons. However, few studies have focused on the long-distance growth of dopaminergic axons from VM transplants. The aim of this study is to identify some of the growth and guidance factors that support directed long-distance growth of dopaminergic axons from VM transplants. Lentivirus encoding either glial cell line-derived neurotrophic factor (GDNF) or netrin-1, or a combination of lenti-GDNF with either lenti-GDNF family receptor α1 (GFRα-1) or lenti-netrin-1 was injected to form a gradient along the corpus callosum. Two weeks later, a piece of embryonic day 14 VM tissue was transplanted into the corpus callosum adjacent to the low end of the gradient. Results showed that tyrosine hydroxylase (TH(+)) axons grew a very short distance from the VM transplants in control groups, with few axons reaching the midline. In GDNF or netrin-1 expressing groups, more TH(+) axons grew out of transplants and reached the midline. Pathways co-expressing GDNF with either GFRα-1 or netrin-1 showed significantly increased axonal outgrowth. Interestingly, only the GDNF/netrin-1 combination resulted in the majority of axons reaching the distal target (80%), whereas along the GDNF/GFRα-1 pathway only 20% of the axons leaving the transplant reached the distal target. This technique of long-distance axon guidance may prove to be a useful strategy in reconstructing damaged neuronal circuits, such as the nigrostriatal pathway in Parkinson's disease.


Assuntos
Axônios/fisiologia , Transplante de Tecido Encefálico/métodos , Neurônios Dopaminérgicos/transplante , Fator Neurotrófico Derivado de Linhagem de Célula Glial/metabolismo , Fatores de Crescimento Neural/metabolismo , Proteínas Supressoras de Tumor/metabolismo , Animais , Western Blotting , Feminino , Humanos , Imuno-Histoquímica , Mesencéfalo/transplante , Camundongos , Netrina-1 , Ratos , Ratos Sprague-Dawley , Transfecção
18.
Parasite Immunol ; 34(4): 224-35, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22251385

RESUMO

The molecular mechanisms that underlie poor birth outcomes in malaria during pregnancy remain poorly defined. To assess the role of host immune responses, mice known to respond differentially to Plasmodium chabaudi AS infection were studied. Following infection at day 0 of pregnancy, A/J mice developed significantly higher parasitemia than C57BL/6 (B6) mice and succumbed to infection. Both strains had evidence of parasite accumulation in the placenta at mid-gestation and aborted, with significantly higher embryo loss in infected A/J mice on day 9. While infection-induced systemic tumour necrosis factor (TNF) and interleukin (IL)-1ß in the latter were significantly higher at day 11, day 10 IL-10 levels were higher in B6 mice. No differences in the levels of splenic lymphocyte subsets, neutrophils or monocytes between infected pregnant A/J and B6 mice were observed, with most cell types expanding in response to infection regardless of pregnancy. Antibody ablation of TNF exacerbated infection in A/J mice and did not ameliorate pregnancy outcome. Thus, malaria induces poor pregnancy outcome in both the mouse strains in the context of quantitatively different systemic inflammatory responses. Further evaluation of the roles of soluble and cellular immune components, particularly at the uteroplacental level, will be required to define the most critical pregnancy-compromising mechanisms.


Assuntos
Aborto Espontâneo/etiologia , Malária/imunologia , Malária/parasitologia , Plasmodium chabaudi/patogenicidade , Complicações Parasitárias na Gravidez/imunologia , Animais , Citocinas/metabolismo , Feminino , Inflamação/imunologia , Malária/complicações , Camundongos , Camundongos Endogâmicos C57BL , Parasitemia/parasitologia , Placenta/parasitologia , Gravidez , Complicações Parasitárias na Gravidez/parasitologia
19.
Ann R Coll Surg Engl ; 93(7): 542-7, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22004638

RESUMO

Earlier diagnosis is a key aim in achieving improved outcomes for patients with cancer. Bone and soft tissue sarcomas represent approximately 1% of all malignant tumours. Delays in diagnosis are frequent both because of their rarity and because the clinical features are easily confused with other conditions. In 2000 advice on earlier diagnosis was widely publicised. This study investigates how two factors that may act as a proxy for delay in diagnosis have varied over a 25-year period and whether there is evidence of improvement. Data on symptom duration and tumour size were collected prospectively on all new sarcoma patients referred to an orthopaedic oncology unit over 25 years. Data were available for 2,568 patients with primary bone sarcomas and 2,366 with soft tissue sarcomas. The mean sarcoma size at diagnosis was 10.7 cm and 9.9 cm respectively. The size of bone sarcomas had not changed over time but there had been a slight decrease in the size of soft tissue sarcomas (10.3 cm before 2000 vs 9.6 cm after 2000, p=0.03). The duration of symptoms reported by patients varied widely with a median of 16 weeks for bone sarcomas and 26 weeks for soft tissue sarcomas. The median duration of symptoms for bone sarcomas had actually increased since 2000 (16 weeks before vs 20 weeks after 2000, p<0.01). It remained unchanged for soft tissue sarcomas. These data show there is huge room for improvement in diagnosing bone and soft tissue sarcomas. New strategies are needed urgently.


Assuntos
Neoplasias Ósseas/patologia , Sarcoma/patologia , Neoplasias de Tecidos Moles/patologia , Adulto , Fatores Etários , Diagnóstico Tardio , Detecção Precoce de Câncer , Feminino , Humanos , Masculino , Fatores Sexuais , Carga Tumoral
20.
Eur J Pediatr Surg ; 21(4): 263-5, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21590655

RESUMO

OBJECTIVE: Aim of the study was determine health care outcomes from the patients' perspective in patients reliant on Mitrofanoff catheterisation for bladder emptying. SUBJECTS/PATIENTS: Patients over the age of 16 dependent on Mitrofanoff catheterisation for bladder emptying were asked to complete a health care outcome questionnaire, the SF-36 (®) Health Survey v2. Quality of life measures for 8 health concepts were compared against published data for the normal population. RESULTS: Out of a total of 25 patients who were eligible for enrolment into our study, we were able to contact 19 patients. The norm-based score for Physical Functioning (PF=50.4), Role Physical (RP=53.8), Bodily Pain (BP=55.6), Vitality (VT=56.9), Social Functioning (SF=51.5), Role Emotional (RE=52.2), and Mental Health (MH=54.6) were all higher than those reported within the normal population (normal=50.0). Physical and mental component summary measures were higher than in the normal population. When compared against age-matched norms our patient group scored higher than the normal population for all measures except Physical Functioning (50.4 vs. 53.4) and physical component summary (51.9 vs. 53.5). The self-reported scores for Vitality, Mental Health and the mental component summary were all statistically significantly better than those seen in the age-matched control population (p<0.01). CONCLUSIONS: Quality of life in patients dependent on Mitrofanoff catheterisation for bladder emptying is good. The SF-36 measures 8 major health care outcomes and in our patients these measures of health were similar to those seen in the general population, rather than the poorer outcomes reported in patients with other chronic medical conditions.


Assuntos
Cateterismo Uretral Intermitente , Qualidade de Vida , Incontinência Urinária/terapia , Adolescente , Estudos de Casos e Controles , Estudos Transversais , Seguimentos , Humanos , Cateterismo Uretral Intermitente/psicologia , Procedimentos de Cirurgia Plástica , Autorrelato , Incontinência Urinária/etiologia , Incontinência Urinária/psicologia , Sistema Urinário/anormalidades , Sistema Urinário/cirurgia , Adulto Jovem
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