433 research outputs found

    Signal Intensity Change on Unenhanced T1-Weighted Images in Dentate Nucleus Following Gadobenate Dimeglumine in Patients With and Without Previous Multiple Administrations of Gadodiamide

    Get PDF
    OBJECTIVES: To evaluate the impact of previous administration of gadodiamide and neural tissue gadolinium deposition in patients who received gadobenate dimeglumine. METHODS: Our population included 62 patients who underwent at least three administrations of gadobenate dimeglumine, plus an additional contrast-enhanced last MRI for reference, divided into two groups: group 1, patients who in addition to gadobenate dimeglumine administrations had prior exposure to multiple doses of gadodiamide; group 2, patients without previous exposure to other gadolinium-based contrast agent (GBCAs). Quantitative analysis was performed on the first and last gadobenate dimeglumine MRIs in both groups. Dentate nucleus-to-middle cerebellar peduncle signal intensity ratios (DN/MCP) and relative change (RC) in signal over time were calculated and compared between groups using generalized additive model. RESULTS: Group 1 showed significant increase in baseline and follow-up DN/MCP compared to group 2 (p < 0.0001). The RC DN/MCP showed a non-statistically significant trend towards an increase in patients who underwent previous gadodiamide (p = 0.0735). CONCLUSION: There is increased T1 signal change over time in patients who underwent gadobenate dimeglumine and had received prior gadodiamide compared to those without known exposure to previous gadodiamide. A potentiating effect from prior gadodiamide on subsequent administered gadobenate dimeglumine may occur. KEY POINTS: • Neural gadolinium deposition is associated with multiple administrations of less stable GBCAs. • Less stable GBCA effect on subsequent more stable GBCA administrations is undetermined. • Significant increase of DN/MCP was seen in patients with previous gadodiamide exposure. • RC DN/MCP showed a non-significant increase in patients who received previous gadodiamide. • Potentiating effects from prior gadodiamide on subsequent administered gadobenate dimeglumine may occur.info:eu-repo/semantics/publishedVersio

    Gadolinium-Based Contrast Agent Accumulation and Toxicity: an Update

    Get PDF
    In current practice, gadolinium-based contrast agents have been considered safe when used at clinically recommended doses in patients without severe renal insufficiency. The causal relationship between gadolinium-based contrast agents and nephrogenic systemic fibrosis in patients with renal insufficiency resulted in new policies regarding the administration of these agents. After an effective screening of patients with renal disease by performing either unenhanced or reduced-dose-enhanced studies in these patients and by using the most stable contrast agents, nephrogenic systemic fibrosis has been largely eliminated since 2009. Evidence of in vivo gadolinium deposition in bone tissue in patients with normal renal function is well-established, but recent literature showing that gadolinium might also deposit in the brain in patients with intact blood-brain barriers caught many individuals in the imaging community by surprise. The purpose of this review was to summarize the literature on gadolinium-based contrast agents, tying together information on agent stability and animal and human studies, and to emphasize that low-stability agents are the ones most often associated with brain deposition.info:eu-repo/semantics/publishedVersio

    Spatio-temporal Models of Lymphangiogenesis in Wound Healing

    Full text link
    Several studies suggest that one possible cause of impaired wound healing is failed or insufficient lymphangiogenesis, that is the formation of new lymphatic capillaries. Although many mathematical models have been developed to describe the formation of blood capillaries (angiogenesis), very few have been proposed for the regeneration of the lymphatic network. Lymphangiogenesis is a markedly different process from angiogenesis, occurring at different times and in response to different chemical stimuli. Two main hypotheses have been proposed: 1) lymphatic capillaries sprout from existing interrupted ones at the edge of the wound in analogy to the blood angiogenesis case; 2) lymphatic endothelial cells first pool in the wound region following the lymph flow and then, once sufficiently populated, start to form a network. Here we present two PDE models describing lymphangiogenesis according to these two different hypotheses. Further, we include the effect of advection due to interstitial flow and lymph flow coming from open capillaries. The variables represent different cell densities and growth factor concentrations, and where possible the parameters are estimated from biological data. The models are then solved numerically and the results are compared with the available biological literature.Comment: 29 pages, 9 Figures, 6 Tables (39 figure files in total

    Use of antibiotic spacers for knee endoprosthesis infections treatment

    Get PDF
    OBJCTIVE: The aim of this study is to evaluate the use of cement spacers impregnated with antibiotics for the treatment of infections in the nonconventional endoprostheses of the knee. METHODOLOGY: We have treated seven patients since 2004 (of which six were submitted to surgery in our service and one patient had been submitted to a primary tumor surgery in another removal service) with deep infection in knee tumor prosthesis. All patients were submitted to endoprosthesis removal and reconstructed with antibiotic cement spacer. All patients were monitored both clinically and by lab tests as for monitoring the evolution, being considered able for reviews after 6 (six) months without infections signs. RESULTS: We have noted a small predominance of infectious processes on the prosthesis inserted on proximal tibia as compared with distal femur (57.1% x 42.9%). The mean follow-up time of patients was 68.2 months. During the follow up, one patient died as a result of the root disease. Six patients out of seven were regarded as cured and one persisted with infection signs and symptoms. CONCLUSION: The results obtained up to date have motivated us to continue using this method of treatment.OBJETIVO: O objetivo do estudo é avaliar a utilização dos espaçadores de cimento acrílico com antibiótico no tratamento das infecções em endopróteses não convencionais de joelho. MÉTODO: Desde de 2004 foram tratados sete pacientes (seis pacientes operados no nosso serviço e um paciente que havia sido submetido a cirurgia primária do tumor em outro serviço) com infecção peri-endoprótese não convencional de joelho. Todos pacientes foram submetidos a retirada da endoprótese e reconstrução com espaçador com cimento acrílico com antibiótico. Todos os pacientes foram monitorados clínica e laboratorialmente quanto ao controle da evolução, sendo considerados aptos para a revisão e recolocação de endoprótese após 06 (seis) meses sem sinais infecciosos RESULTADOS: Notamos um discreto predomínio do do processo infeccioso nas próteses realizadas na tíbia proximal em comparação com o fêmur distal (57,1% x 42,9%). O seguimento médio dos pacientes foi 68,2 meses. Durante o seguimento, um paciente faleceu devido a doença de base. Dos sete pacientes, 6 foram considerados curados e um persistiu com sinais e sintomas de infecção. CONCLUSÃO: Os resultados obtidos até o momento tem motivado a continuidade deste método de tratamento.Universidade Federal de São Paulo (UNIFESP) Escola Paulista de Medicina Departamento de Ortopedia e TraumatologiaUNIFESP, EPM, Depto. de Ortopedia e TraumatologiaSciEL

    Science PhD Career Preferences: Levels, Changes, and Advisor Encouragement

    Get PDF
    Even though academic research is often viewed as the preferred career path for PhD trained scientists, most U.S. graduates enter careers in industry, government, or “alternative careers.” There has been a growing concern that these career patterns reflect fundamental imbalances between the supply of scientists seeking academic positions and the availability of such positions. However, while government statistics provide insights into realized career transitions, there is little systematic data on scientists' career preferences and thus on the degree to which there is a mismatch between observed career paths and scientists' preferences. Moreover, we lack systematic evidence whether career preferences adjust over the course of the PhD training and to what extent advisors exacerbate imbalances by encouraging their students to pursue academic positions. Based on a national survey of PhD students at tier-one U.S. institutions, we provide insights into the career preferences of junior scientists across the life sciences, physics, and chemistry. We also show that the attractiveness of academic careers decreases significantly over the course of the PhD program, despite the fact that advisors strongly encourage academic careers over non-academic careers. Our data provide an empirical basis for common concerns regarding labor market imbalances. Our results also suggest the need for mechanisms that provide PhD applicants with information that allows them to carefully weigh the costs and benefits of pursuing a PhD, as well as for mechanisms that complement the job market advice advisors give to their current students

    One health: the importance of companion animal vector-borne diseases

    Get PDF
    The international prominence accorded the 'One Health' concept of co-ordinated activity of those involved in human and animal health is a modern incarnation of a long tradition of comparative medicine, with roots in the ancient civilizations and a golden era during the 19th century explosion of knowledge in the field of infectious disease research. Modern One Health tends to focus on zoonotic pathogens emerging from wildlife and production animal species, but one of the most significant One Health challenges is rabies for which there is a canine reservoir. This review considers the role of small companion animals in One Health and specifically addresses the major vector-borne infectious diseases that are shared by man, dogs and cats. The most significant of these are leishmaniosis, borreliosis, bartonellosis, ehrlichiosis, rickettsiosis and anaplasmosis. The challenges that lie ahead in this field of One Health are discussed, together with the role of the newly formed World Small Animal Veterinary Association One Health Committee
    corecore