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51.
52.
Albert Kingman 《Journal of periodontal research》1992,27(4):378-389
Simulation studies were conducted to address specific statistical issues which arise in the design and analysis of gingivitis studies whose principal aim is the demonstration of superiority or equivalence of one product to another. The effects of measurement scale, using differences or ratios of group means, particular statistical test produces and specific rules demonstrating superiority or equivalence were investigated. An alternative concept to equivalence—denoted “least as good”—was also defined and evaluated. For a wide class of possible distributions of gingivitis scores, characterized by specific gamma distributions, the student-t test applied to means of subject GI gingivitis scores proved to be the most powerful of the test produces considered, having statistical properties quite similar to the randomization or permutation test procedure. Transformations of subject GI mean gingivitis scores did not produce an advantage in demonstrating either superiority or equivalence, and in some cases made it more difficult. Little difference was observed in test results when using the difference in group means as compared with using the ratio of group means for demonstrating either equivalence or superiority. The clinically significant rule produced the lowest false-positive rates for products slightly better than the active control, and similar false-positive and -negative rates as the statistically significant rule for products clearly superior to the active control. Demonstration of product equivalence will require more subjects per group than demonstrating product superiority, the size of this difference being a function of the definition of superiority that is accepted. Showing that the 90% confidence interval for 100*R is completely contained within the [90%, 110%] interval is the preferred method of demonstrating equivalence today, although much more research needs to be done to improve methods for demonstrating product equivalence. The “least as good” alternative to “equivalence” makes it easier to demonstrate “equivalence” for products slightly better than the active control product, but both experience great difficulty in demonstrating equivalence for lest products not quite as good as the active control. 相似文献
53.
The authors present a patient with a complex vascular malformation composed of bilateral spontaneous carotid-cavernous fistulas (CCF's). The abnormality was supplied on the right side by the right external carotid artery (ECA) and the right internal carotid artery (ICA), and on the left side only by the left ICA. There was also an arteriovenous communication between the right ECA and the lateral sinus. Surgical embolization of both cavernous sinuses with oxidized cellulose was achieved on one side by direct puncture and on the other through one of its venous affluents, successfully occluding both CCF's and preserving the patency of both ICA's without any neurological deficit. The arteriovenous communication between the right ECA and the lateral sinus was occluded by embolization of the occipital artery and ligation of the right ECA. 相似文献
54.
55.
Cess A. Visser Jan T. Keijer Jeroen J. Bax Albert C. van Rossum Frans C. Visser 《The international journal of cardiovascular imaging》1997,13(5):415-431
In the past 20 years, radionuclide scintigraphy has proven to be a sensitive clinical tool in the assessment of myocardial perfusion abnormalities. Magnetic resonance imaging may also be used to study myocardial perfusion, but its potential value still has to emerge in the clinical setting. This review addresses the potential and achievements of both methods in clinical cardiology. 相似文献
56.
Jan Paul Ouwens Wim van der Bij Thomas W van der Mark Albert Geertsma Do A Piers Wim J de Boer Gerard H Ko?ter 《The Journal of heart and lung transplantation》2004,23(1):115-121
BACKGROUND: A decrease in forced expiratory volume in 1 second (FEV(1)) as a diagnostic criterion for bronchiolitis obliterans syndrome (BOS) after single lung transplantation may be influenced significantly by the presence of the native lung. To quantify and to discriminate between the relative contribution of graft and native lung to the FEV(1), we retrospectively investigated the diagnostic value of combined FEV(1) measurements and ventilation scintigraphy in pulmonary dysfunction after single lung transplantation in 11 recipients with pulmonary vascular disease, 3 with obstructive lung disease, and 3 with restrictive lung disease. METHODS: We assessed function of the native lung and the graft, and subsequently calculated an adjusted grading of BOS by correcting routine FEV(1) measurements using linear interpolation of bi-annual lung ventilation scans. RESULTS: The contribution of the native lung to the total FEV(1) was slight (median, 9%) in recipients with obstructive disease compared with recipients with vascular (38%) or restrictive lung diseases (27%). Adjusted BOS grading was not useful in patients with obstructive disease. In the other patient groups, the onset of adjusted BOS Grade 1 and standard BOS Grade 1 was at a median of 220 days (range, 127-1146 days) and 836 days (184-3065 days), respectively. CONCLUSION: Ventilation scintigraphy is a useful adjunct in the (early) diagnosis of BOS in recipients of single lung transplants who have vascular and restrictive lung diseases. 相似文献
57.
Mark R. Beauchamp Albert V. Carron Serena McCutcheon Oliver Harper 《Annals of behavioral medicine》2007,33(2):200-206
Background: A growing body of research suggests that older exercisers prefer to exercise alone rather than in group-based settings. One
limitation of these studies, however, has been that researchers have failed to take into account the age-related characteristics
of groups when asking adults about their preferences for exercise settings.Purpose: The overall purpose of this study was to examine the exercise preferences of 947 adults for involvement in standard exercise
classes populated by participants from various categories across the age spectrum.Results: The results revealed that when faced with the prospect of exercising with considerably older or younger exercisers, participants
found such an exercise context to be largely unappealing. However, in accordance with the basic tenets of self-categorization
theory, the results revealed that older and younger adults alike express a positive preference for exercising in standard
exercise classes comprised of similarly aged participants.Conclusions: The findings of this study challenge a growing call for exercise interventions for older adults to be primarily directed
at the individual-level, and suggest that group-related intervention strategies may indeed be attractive to older exercisers. 相似文献
58.
Abhishek Srivastava Anirban Ghosh Somnath Saha V. P. Saha Debdulal Chakraborty 《Indian journal of otolaryngology and head and neck surgery》2007,59(4):322-326
38 cases of sarcoma of head and neck region were analysed in a retrospective way in relation to age, anatomic location, histological,
clinical profile, and surgical approaches. Compared to other types of head and neck neoplasms, such as squamous cell carcinoma,
soft tissue sarcomas have low rates of regional metastases. However the biological behaviour of soft tissue sarcoma is more
aggressive specially in paediatric age group. In the present series, CT scan was considered as the primary modality of investigation.
Surgery generally has been recommended as the primary method of treatment for achieving local control, except in those high-grade
tumours arising in sites not amenable to resection. 3-year and 5-year survival rates in this present series 50% and 31.6%
respectively. 相似文献
59.
60.
Aurélie Daelemans Thierry Leloup Christine Decaesteker Albert De Mey 《Nordisk plastikkirurgisk forening [and] Nordisk klubb for handkirurgi》2006,40(6):335-344
Our aim was to develop and validate a new method to assess objectively and quantitatively the morphology of the nostrils after nasal or nasolabial surgery. We used digital analysis using specific mathematical algorithms to assess several geometric measurements, particularly of facial asymmetry, expressed in adimensional units. Forty-five patients with no facial anomalies (control group) were used initially to evaluate the method and to obtain variables for statistical reference. Thirty-five patients operated on for unilateral cleft lip and palate (cleft group) were then analysed and compared with the control group. Individual scores were obtained for each patient, computed, and correlated with those established by a lay panel. Statistical analysis showed good sensitivity and reliability (R>0.8). 相似文献