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Judith D. Goldberg Arnold I. Weiss Kenneth J. Koury 《Journal of clinical periodontology》1986,13(5):411-414
In order to make effective use of the statistical theory of design of clinical trials for chronic diseases such as periodontal disease, certain issues must be considered. Any clinical trial requires that the disease definition be well-specified; that patient eligibility be explicit; that the observation times be explicit; that the duration and endpoint of therapy be specified; that the duration of subsequent followup observation be specified; and that the unit of observation (e.g., tooth, set of teeth, patient) be defined. In a chronic disease, the potential biases that can readily be introduced by self-selection of patients who enter the trial and/or who return for subsequent observation become more important, because subjects are required to remain on treatment and/or observation for prolonged periods. Further, the cyclical nature of some chronic diseases may require special attention to baseline definitions of active disease and disease outcome. These issues are illustrated with examples from clinical trials of hypertension, breast cancer screening, and Polycythemia Vera. Implications for periodontal disease are discussed. 相似文献
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Alemtuzumab (CAMPATH 1H) Induction Therapy in Cadaveric Kidney Transplantation—Efficacy and Safety at Five Years 总被引:2,自引:0,他引:2
Christopher J. E. Watson J. Andrew Bradley Peter J. Friend John Firth Craig J. Taylor John R. Bradley Kenneth G. C. Smith Sathia Thiru Neville V. Jamieson Geoff Hale Herman Waldmann Roy Calne 《American journal of transplantation》2005,5(6):1347-1353
Alemtuzumab is a powerful lymphocyte depleting antibody currently being evaluated in solid organ transplantation. This paper describes 5-year results of a single center study of alemtuzumab as induction in renal transplantation. Thirty-three renal transplant recipients received 20 mg alemtuzumab on day 0 and 1, followed by half-dose cyclosporin monotherapy (trough concentration 75-125 ng/mL) from day 3. They were compared in a retrospective contemporaneous-controlled manner with 66 kidney transplant recipients transplanted in the same period and center who received conventional immunosuppression with cyclosporin, azathioprine and prednisolone. In the alemtuzumab group 12% of recipients died compared to 17% in the control group (p = 0.48); likewise graft loss was similar in both groups (21% vs. 26%, respectively, p = 0.58). Incidence of acute rejection was also comparable at 5 years (31.5% vs. 33.6%), although the pattern of rejection was different with 14% patients in the alemtuzumab group experiencing rejection over 1 year post-transplant compared to none in the control group. There was no significant difference between groups in terms of infection or serious adverse events. While acknowledging the limitations of a relatively small single-center study, results suggest that alemtuzumab induction allowed satisfactory long-term patient and graft survival equivalent to that seen with standard triple immunosuppression, while avoiding steroid therapy. 相似文献
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Scalp electrical recording during paralysis: quantitative evidence that EEG frequencies above 20 Hz are contaminated by EMG. 总被引:2,自引:0,他引:2
Emma M Whitham Kenneth J Pope Sean P Fitzgibbon Trent Lewis C Richard Clark Stephen Loveless Marita Broberg Angus Wallace Dylan DeLosAngeles Peter Lillie Andrew Hardy Rik Fronsko Alyson Pulbrook John O Willoughby 《Clinical neurophysiology》2007,118(8):1877-1888
OBJECTIVE: To identify the possible contribution of electromyogram (EMG) to scalp electroencephalogram (EEG) rhythms at rest and induced or evoked by cognitive tasks. METHODS: Scalp EEG recordings were made on two subjects in presence and absence of complete neuromuscular blockade, sparing the dominant arm. The subjects undertook cognitive tasks in both states to allow direct comparison of electrical recordings. RESULTS: EEG rhythms in the paralysed state differed significantly compared with the unparalysed state, with 10- to 200-fold differences in the power of frequencies above 20 Hz during paralysis. CONCLUSIONS: Most of the scalp EEG recording above 20 Hz is of EMG origin. Previous studies measuring gamma EEG need to be re-evaluated. SIGNIFICANCE: This has a significant impact on measurements of gamma rhythms from the scalp EEG in unparalysed humans. It is to be hoped that signal separation methods will be able to rectify this situation. 相似文献
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Amit Badhwar Thomas L Forbes Marge B Lovell Alison A Dungey Sarah D McCarter Jeffrey R Scott Guy DeRose Kenneth A Harris Richard F Potter 《Canadian journal of surgery》2004,47(5):352-358
BACKGROUND: Ischemic preconditioning (IPC) has been found in animals to have a protective effect against future ischemic injury to muscle tissue. Such injury is unavoidable during some surgical procedures. To determine whether chronic ischemia in the lower extremities would imitate IPC and reduce ischemic injury during vascular surgery, we designed a controlled clinical study. PATIENTS AND METHODS: Two groups of patients at a university-affiliated medical centre with chronic lower-extremity ischemia served as models of IPC: 6 patients awaiting femoral distal bypass (FDB) and 4 scheduled for aortobifemoral (ABF) bypass grafting for aortoiliac occlusive disease. Seven patients undergoing elective open repair of an infrarenal abdominal aortic aneurysm (AAA) were chosen as non-IPC controls. Three hematologic indicators of skeletal-muscle injury, lactate dehydrogenase (LDH), creatine kinase (CK) and myoglobin, were measured before placement of the proximal clamp, during surgical ischemia, immediately upon reperfusion, 15 minutes after and 1 hour after reperfusion, and during the first, second and third postoperative days. RESULTS: Baseline markers of skeletal-muscle injury were similar in all groups. In postreperfusion samples, concentrations of muscle-injury markers were significantly lower in the 2 PC groups than in the control group. For example, at day 2, LDH levels were increased by about 30% over baseline measures in the elective AAA (control) group, whereas levels in the FDB and ABF groups remained statistically unchanged from baseline. Myoglobin in controls had increased by 977%, but only by 160% in the FDB and 528% in the ABF groups. CK levels, in a similar trend, were 1432% higher in the control group and only 111% (FDB) and 1029% (ABF) in the study groups. Taken together, these data represent a significant level of protection. CONCLUSIONS: Patients with chronic lower-extremity ischemia suffered less severe ischemic injury after a period of acute ischemia than those with acute ischemia alone. Ischemic preconditioning is one proposed mechanism to help explain this protective effect. 相似文献
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Susan W. Volk VMD PhD ; Antoneta Radu BS ; Liping Zhang MS ; Kenneth W. Liechty MD 《Wound repair and regeneration》2007,15(5):736-747
Chronic wounds create a formidable clinical problem resulting in considerable morbidity and healthcare expenditure. The etiology for wound healing impairment appears to be multifactorial; however, ischemia is a common factor in most types of chronic wounds. Ideal therapy for such wounds would be to correct deficiencies in growth factors and matrix components and provide cellular precursors required for timely wound closure. We hypothesized that stromal progenitor cell (SPC) therapy could correct the ischemic wound-healing defect through both direct and indirect mechanisms. To test this hypothesis, we used the ischemic rabbit ear model of chronic wound healing. We found that treatment of the wounds with SPCs was able to reverse the ischemic wound-healing impairment, with improved granulation tissue formation and reepithelialization compared with vehicle or bone marrow mononuclear cell controls. In vitro, SPCs were found to produce factors involved in angiogenesis and reepithelialization, and extracellular matrix components, providing evidence for both direct and indirect mechanisms for the observed correction of the healing impairment in these wounds. Treatment of ischemic wounds with SPCs can dramatically improve wound healing and provides a rationale for further studies focused on SPCs as a potential cellular therapy in impaired wound healing. 相似文献