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1.
2.
Short-Ti inversion-recovery pulse sequence: analysis and initial experience in cancer imaging 总被引:2,自引:0,他引:2
Inversion recovery (IR), commonly considered a pulse sequence capable of producing T1-weighted images with excellent display of normal anatomy, is versatile: The null point and peak time provide a useful, succinct summary of the properties of IR and its capacity for producing both T1- and T2-weighted images. Shortening of the inversion time (TI) and creation of a short-TI inversion-recovery (STIR) pulse sequence increases sensitivity to malignancy and other abnormalities by making the effects of prolonged T1 and T2 on signal intensity additive and by nulling the signal from fat. The authors examined over 300 patients with various malignancies and compared STIR images with T1- and T2-weighted images obtained at 0.5 T. In 43 cases, signal-difference-to-noise ratios (SD/Ns) were calculated between tumor, fat, and muscle. In general, STIR images demonstrated tumor as a conspicuously high-intensity area in a background of muted, discernible anatomic detail. The good contrast achieved with STIR sequences between tumor and fat (SD/N = 18.1) and tumor and muscle (SD/N = 12.9) consolidated into a single image the information contained separately on T1- and T2-weighted images, which facilitates efficient detection and localization of malignancy. 相似文献
3.
Federico Ferrando-Castagnetto Enrique Macri Alejandro Silva Darío Padula Gastón Garcés 《Educación Médica》2019
Introduction
Although an objective structured clinical examination (OSCE) format has been applied in Uruguay since 2004, and providing reliable performance measures, perceptions of it properties and level of student satisfaction have not been determined.Objective
To evaluate the face validity of OSCE format as a contribution to its local feasibility study.Material and methods
At the end of the introductory clinical course, the sub-cohort enrolled at the University Hospital responded to a 28-item questionnaire aimed at exploring perceptions about the properties of the OSCE about the potential factors ‘design’ and ‘apparent validity’. After analysing the reliability of the original questionnaire, the questionnaire was refined in an attempt to provide a shorter and more reliable tool.Results
The original questionnaire showed good internal consistency (Cronbach alpha = 0.70), with a dominance of ‘agreement/total agreement’ opinions on authenticity of the stimuli, dynamic, relevance, and equity of the test. Students perceived organisational obstacles during the test, expressing disagreement to include some stations only aimed at assessing communication skills, and requiring personalised feedback sessions. The refined version of the questionnaire provides consistent measures on student perceptions and is a useful tool that can be widely applied. A discussion is presented on the contributions of this experience to a comprehensive feasibility study of the new format during curriculum transition.Conclusions
The OSCE is well evaluated by students at the end of the propaedeutic course, supporting its validity. Educational potentials of the new format should be exploited, providing effective feedback to students, clinical teachers, and institutions. 相似文献4.
The effects of antioxidant supplementation during Percoll preparation on human sperm DNA integrity 总被引:20,自引:6,他引:20
Hughes CM; Lewis SE; McKelvey-Martin VJ; Thompson W 《Human reproduction (Oxford, England)》1998,13(5):1240-1247
The integrity of sperm DNA is crucial for the maintenance of genetic
health. A major source of damage is reactive oxygen species (ROS)
generation; therefore, antioxidants may afford protection to sperm DNA. The
objectives of the study were, first, to measure the effects of antioxidant
supplementation in vitro on endogenous DNA damage in spermatozoa using the
single cell gel electrophoresis (comet) assay and, second, to assess the
effect of antioxidant supplementation given prior to X-ray irradiation on
induced DNA damage. Spermatozoa from 150 patients were prepared by Percoll
centrifugation in the presence of ascorbic acid (300, 600 microM), alpha
tocopherol (30, 60 microM), urate (200, 400 microM), or acetyl cysteine (5,
10 microM). DNA damage was induced by 30 Gy X-irradiation. DNA strand
breakage was measured using the comet assay. Sperm DNA was protected from
DNA damage by ascorbic acid (600 microM), alpha tocopherol (30 and 60
microM) and urate (400 microM). These antioxidants provided protection from
subsequent DNA damage by X-ray irradiation. In contrast, acetyl cysteine or
ascorbate and alpha tocopherol together induced further DNA damage.
Supplementation in vitro with the antioxidants ascorbate, urate and alpha
tocopherol separately has beneficial effects for sperm DNA integrity.
相似文献
5.
Carlo Capella Luciana Usellini Mauro Papotti Luigia Macri Giovanna Finzi Vincenzo Eusebi Gianni Bussolati 《Ultrastructural pathology》1990,14(4):321-334
The ultrastructural patterns of neuroendocrine (NE) differentiated breast carcinomas are analyzed and discussed. Reports in the literature describe wide variations in the size of observed dense-core membrane-bound granules and discrepancies in their interpretation. In the present study 24 cases of breast carcinoma with recognized morphologic, histochemical, and immunocytochemical features of NE tumors were investigated. Five different types of dense-core granules of neurosecretory (NS) type (confirmed by the ultrastructural localization of chromogranin A) and five different cell types were recognized. Some amphicrine cells were found to contain both mucin and NS granules. Another notable ultrastructural feature of breast NE carcinomas was the presence of clear vesicles of presynaptic type, which correlated with expression of synaptophysin. 相似文献
6.
How to use Chlamydia antibody testing in subfertility patients 总被引:1,自引:9,他引:1
Screening for tubal factor subfertility by means of Chlamydia antibody
testing (CAT) was introduced into the initial work-up of subfertile couples
several years ago. The results reported, however, are heterogeneous, and no
uniformity exists in cut-off levels of titres, or in definitions of tubal
factor subfertility. We performed a prospective cohort study to evaluate
the implications of varying the definitions of tubal pathology and of
modifying the cut-off levels on the clinical impact of CAT in predicting
tubal factor subfertility. In 227 consecutive patients who attended our
fertility clinic, the Chlamydia IgG antibody titre was determined and
related to tuboperitoneal abnormalities at laparoscopy as a reference
standard. According to received operating characteristic (ROC) curve
analysis, a titre of 16 is the optimum cut-off level. Increasing the
cut-off level improves specificity and positive likelihood ratio (LR+), at
the expense of sensitivity and negative LR (LR-). Changing the definition
of tubal factor subfertility from unspecified tuboperitoneal abnormalities
into extensive adhesions and/or bilateral distal tubal occlusion improves
LR+, LR- and kappa significantly. We conclude that CAT is more accurate in
predicting severe distal tubal pathology than unspecified tuboperitoneal
abnormalities. Although from a statistical point of view a titre of 16 is
the optimum cut-off level, from a clinical point of view 32 or 64 may be
preferable, depending on the aim of screening and the inception cohort.
相似文献
7.
8.
A. Greco A. Gallo M. Fusconi G. Magliulo R. Turchetta C. Marinelli G.F. Macri A. De Virgilio M. de Vincentiis 《Autoimmunity reviews》2013,12(3):396-400
ObjectivesThe objective of our study was to review our current knowledge of the aetiopathogenesis of Cogan's syndrome, including viral infection and autoimmunity, and to discuss disease pathogenesis with relevance to pharmacotherapy.Systematic review methodologyRelevant publications on the aetiopathogenesis and pharmacotherapy of Cogan's syndrome from 1945 to 2012 were analysed.Results and conclusionsCogan's syndrome is a rare autoimmune vasculitis, and its pathogenesis is unknown. Infection, but primarily autoimmunity, may play contributing roles in the pathogenesis of this disease. It is characterised by ocular and audiovestibular symptoms similar to those of Meniere's syndrome. Approximately 70% of patients have systemic disease, of which vasculitis is considered the pathological mechanism. The immunologic theory is based on the release of auto-antibodies against corneal, inner ear and endothelial antigens, and of anti-nuclear cytoplasmic auto-antibodies (ANCA).Corticosteroids are the first line of treatment, and multiple immunosuppressive drugs have been tried with varying degrees of success. Tumour necrosis factor (TNF)-alpha blockers are a category of immunosuppressive agents representing a recent novel therapeutic option in Cogan's syndrome. 相似文献
9.
R. A. Greenberg K. W. Anstey R. Macri A. Heesters S. Bean R. Zlotnik Shaul 《HEC forum》2014,26(2):135-146
The literature fails to reflect general agreement over the nature of the services and procedures provided by bioethicists, and the training and core competencies this work requires. If bioethicists are to define their activities in a consistent way, it makes sense to look for common ground in shared communities of practice. We report results of a survey of the services and procedures among bioethicists affiliated with the University of Toronto Joint Centre for Bioethics (JCB). This is the largest group of bioethicists working in healthcare organizations in Canada. The results suggest there are many common services and procedures of JCB bioethicists. This survey can serve as a baseline for further exploration of the work of JCB bioethicists. Common practices exist with respect to the domains of practice, individual reporting relationships, service availability within business hours and the education and training of the bioethicist. 相似文献
10.
Mika VJ Mustonen Seppo Pyrh?nen Pirkko-Liisa Kellokumpu-Lehtinen 《World journal of clinical oncology》2014,5(3):393-405
Although more widespread screening and routine adjuvant therapy has improved the outcome for breast cancer patients in recent years, there remains considerable scope for improving the efficacy, safety and tolerability of adjuvant therapy in the early stage disease and the treatment of advanced disease. Toremifene is a selective estrogen receptor modifier (SERM) that has been widely used for decades in hormone receptor positive breast cancer both in early and late stage disease. Its efficacy has been well established in nine prospective randomized phase III trials compared to tamoxifen involving more than 5500 patients, as well as in several large uncontrolled and non-randomized studies. Although most studies show therapeutic equivalence between the two SERMs, some show an advantage for toremifene. Several meta-analyses have also confirmed that the efficacy of toremifene is at least as good as that of tamoxifen. In terms of safety and tolerability toremifene is broadly similar to tamoxifen although there is some evidence that toremifene is less likely to cause uterine neoplasms, serious vascular events and it has a more positive effect on serum lipids than does tamoxifen. Toremifene is therefore effective and safe in the treatment of breast cancer. It provides not only a useful therapeutic alternative to tamoxifen, but may bring specific benefits. 相似文献