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101.
R van der Weide KJ Zuiderveld WP Mali MA Viergever 《Canadian Metallurgical Quarterly》1998,17(5):831-841
Coil embolization is a safe treatment for cerebral aneurysms only if the width of the neck in relation to the fundus of the aneurysm is small. Therefore, accurate visualization of the aneurysmal neck is required both in the diagnostic process and during the intervention. Conventional digital subtraction angiography (DSA) is still the preferred modality for the examination of cerebrovascular abnormalities like aneurysms, but it often does not provide the required morphological characteristics due to the suboptimal selection of projection angles and resulting overprojections of surrounding vasculature. This paper presents a method for performing a computer-assisted calculation of the optimal projection angles for DSA by post-processing computed tomographic angiography (CTA) volume data using ray-casting techniques and a combination of image processing algorithms. By means of phantom studies, retrospective simulations of angiograms, and in vivo applications of calculated optimal viewing angles, it is demonstrated that the proposed method results in better angiographic projections of the neck of saccular aneurysms with small neck-fundus ratio than those acquired at standard angles prescribed by clinical protocols. 相似文献
102.
We previously described a high incidence of digit/limb anomalies in the offspring of A/J mice subjected to surgery on day 12.5 postconception (p.c.), but not in the offspring of untreated control mice. To investigate the cause of these defects, we compared the offspring of mice in experimental groups involving adrenalectomy, sham adrenalectomy, blood sampling, and anesthesia with the offspring of control mice. All treatments significantly reduced fetal weight and increased resorptions as compared with the controls. The highest incidence of digit anomalies occurred in the offspring of dams from which blood samples had been drawn on days 12.5, 14.5, and 15.5 p.c. The incidence of isolated cleft palate was also increased in the offspring of mice that had been subjected to blood sampling. We conclude that digit anomalies in the offspring of A/J mice result from fetal vascular disruptive phenomena subsequent to maternal blood loss induced hypovolemia and hypoperfusion to the uterus and placenta as has been suggested for uterine vascular clamping, misoprostol, chorionic villus sampling, and cocaine teratogenesis. The etiology for cleft lip in these mice may involve mechanisms unrelated to uterine/placental hypoperfusion. 相似文献
103.
KP Braun RA de Graaf WP Vandertop RH Gooskens KA Tulleken K Nicolay 《Canadian Metallurgical Quarterly》1998,40(6):832-839
The severity and progression of ventricular enlargement, the occurrence of cerebral edema, and the localization of ischemic metabolic changes were investigated in a rat model of hydrocephalus, using in vivo 1H MR spectroscopic imaging (SI) and diffusion weighted MRI (DW MRI). Hydrocephalic rats were studied 1, 2, 4, and 8 weeks after injection of kaolin into the cisterna magna. Parametric images of the apparent diffusion coefficient (ADC) revealed a varying degree of ventriculomegaly in all rats, with different time courses of ventricular expansion. Extracellular white matter edema was observed during the early stages of hydrocephalus, most extensively in cases of progressive ventriculomegaly. In gray matter regions, ADC values were not changed, compared with controls. In case of fatal hydrocephalus, high lactate levels were observed throughout the whole brain. In all other rats, at all time points after kaolin injection, lactate was detected only in voxels containing cerebrospinal fluid. This suggests accumulation of lactate in the ventricles, and/or an ongoing periventricular production of lactate as a consequence of cerebral ischemia in experimental hydrocephalus. 相似文献
104.
105.
WP Goldman JD Baty VD Buckles S Sahrmann JC Morris 《Canadian Metallurgical Quarterly》1998,55(5):674-680
We evaluated the data of the National Collegiate Athletic Association Injury Surveillance System on collegiate wrestling with a focus on musculoskeletal injuries. Over 800,000 athlete-exposures during an 11-year period compose these data. Findings particular to wrestling and a comparison with other collegiate sports are included. Collegiate wrestling had a relatively high rate of injury at 9.6 injuries per 1000 athlete-exposures. It was second to spring football in total injury rate. Most injuries in this study were not serious, with 6.3% resulting in surgery and 37.6% resulting in a week or more off from wrestling. There was only one catastrophic, nonfatal injury. The knee, shoulder, and ankle were the most commonly injured regions, and injuries to them were often the more serious. Sprains, strains, and contusions were the most common injury types. Takedowns and sparring were the most common activities at the time of injury. Mechanism of injury was evaluated; rotation about a planted foot and contact with environmental objects were identified as areas needing further attention. Illegal action accounted for only 4.6% of injuries in competition. Competition had a significantly higher injury rate than practice, but the injury profiles of these two areas showed both to be equally important. The preseason and regular season had higher injury rates than the postseason, but, again, the injury profiles of these periods were similar. Injury percentages were similar among the 10 weight classes. 相似文献
106.
107.
WP Maksymowych C Gorodezky A Olivo C Alaez C Wong R Burgos-Vargas J Sanchez-Corona C Ramos-Remus AS Russell 《Canadian Metallurgical Quarterly》1997,24(5):904-907
OBJECTIVE: HLA class II encoded factors may influence the phenotype of ankylosing spondylitis (AS). These include HLA DRB1*07 for peripheral arthritis, and polymorphism of the HLA-linked LMP2 locus and HLA DRB1*08 for acute anterior uveitis (AAU). We studied the relationship between DRB1*08 and disease phenotype in additional populations of individuals with AS. METHODS: The patient population included 385 unrelated HLA-B27 positive individuals with AS. These included 204 Caucasians and 2 populations of Mexican Mestizo with AS: 106 with predominately adult onset disease from Guadalajara and 75 with predominately juvenile onset disease from Mexico City. The control population of 428 individuals included 210 random and 36 HLA-B27 positive unrelated Canadian Caucasians and 173 random and 9 HLA-B27 positive Mexican Mestizo from Mexico City. DRB1*08 typing was by sequence specific polymerase chain reaction. RESULTS: A significantly higher prevalence of DRB1*08 was observed in Mexican patients with juvenile onset disease (44.9%) and especially those with undifferentiated spondyloarthropathy (55.6%) compared to normal unrelated Mexican Mestizo (25.4%) (p < 0.01 for both) and in patients with undifferentiated spondyloarthropathy versus B27 controls (11.1%) (p = 0.03), although no significant differences were observed in within patient group comparisons based on phenotypic features of disease such as AAU and age at onset. No significant relationship between DRB1*08 and disease phenotype was evident in Caucasian individuals. CONCLUSION: Our data suggest DRB1*08 may influence the phenotype of spondyloarthritis in Mexican Mestizo, but do not support the view that DRB1*08 influences the development of AAU, as reported in a Japanese population. 相似文献
108.
109.
High dose chemotherapy and stem-cell rescue (bone marrow transplantation) is used increasingly in the treatment of malignant disorder. Numerous trials have demonstrated the effectiveness of bone marrow transplantation in the treatment of non-Hodgkin's lymphoma. However, there are many unanswered questions as to the role of high-dose therapy in certain subtypes of lymphoma, the timing of transplant, and even the type of transplant to perform. An attempt will be made to clarify many of these unanswered questions. The utilization of high-dose therapy for non-Hodgkin's lymphoma is recommended for most patients who have relapsed after initial therapy. Transplantation in first remission is not recommended routinely. Allogeneic bone marrow transplantation should by reserved for individuals with poorly responding disease or in individuals with bone marrow involvement. The precise roles of purging and transplantation of individuals with low grade lymphoma are being investigated. 相似文献
110.