BACKGROUND: In an attempt to reduce late referral and to improve the care of patients with chronic kidney disease (CKD), different organizations have issued guidelines on when to refer patients to the nephrologist. Most suggest referral of patients with a GFR below 60 ml/min/1.73 m2, and demand referral if the GFR is below 30 ml/min/1.73 m2. It is recommended to use the abbreviated MDRD equation to estimate GFR. This formula is, however, sensitive to the creatinine assay methodology. In addition, the impact of the implementation of such guidelines on the nephrology practice has never been evaluated. This study (i) identifies the true burden of CKD in a population and simulates the effects of a 100% implementation of the guidelines on the nephrology work load, and (ii) evaluates the validity of the estimated GFR using the abbreviated MDRD formula when routinely provided. METHODS: Different laboratories (both hospital and private) in our region were asked to report on all the serum creatinine values performed during the first week of December 2004. If patients had more than one determination, only the lowest serum creatinine value was retained. Patients already known to a nephrology unit were not included. GFR was calculated using the abbreviated MDRD, using the serum creatinine as reported by these laboratories, or after correction to the MDRD-standard using different published equations. RESULTS: 20,108 patients, with a mean age of 53.4+/-16.2 years, 48% females, had at least one serum creatinine determination in the observation period. According to the K/DOQI CKD classification, 20.2, 1.6 and 0.8% of females and 13.3, 1.6 and 0.6% of males were in stage 3, 4 and 5, respectively, when the abbreviated MDRD formula was used with the serum creatinine value as reported by the laboratories. Important differences in classifications were obtained when the different correction formulae for creatinine were applied. According to the current recommendations, this would lead to a mandatory referral of 1650-2400 CKD stage 4 patients per 100 000 inhabitants and a suggested referral of another 4100-15 360 CKD stage 3 patients per 100,000 inhabitants to a nephrology unit. CONCLUSION: Implementation of the current guidelines for referral of CKD patients to nephrologists would lead to an overload of the nephrology care capacities. Large differences in estimated GFRs with different corrections for serum creatinine are observed, resulting in important CKD classification differences. Standardization of serum creatinine assays is mandatory before guidelines, and especially the routine provision of the estimated GFR by the abbreviated MDRD formula, can be implemented in clinical practice. 相似文献
The basilar artery is the only large artery in which two flows merge, and this is reflected in the flow downstream. We report quantitative flow — velocity measurements with a phase-based MR technique, i.e. the Fourier velocity encoding method, in the basilar artery of a volunteer. To our knowledge, this has not previously been performed successfully. A comparison is made with the results of flow velocity measurements in the basilar artery with transcranial Doppler ultrasonography; the techniques agreed very well. Although Doppler ultrasonography is still most widely used, no information on the flow rate and the flow velocity distribution in the basilar artery can be provided. MR flow measurement techniques appear promising when detailed information on the flow velocity distribution and flow rate is needed. 相似文献
Background: Intravenous infusion of lidocaine decreases postoperative pain and speeds the return of bowel function. The authors therefore tested the hypothesis that perioperative lidocaine infusion facilitates acute rehabilitation protocol in patients undergoing laparoscopic colectomy.
Methods: Forty patients scheduled to undergo laparoscopic colectomy were randomly allocated to receive intravenous lidocaine (bolus injection of 1.5 mg/kg lidocaine at induction of anesthesia, then a continuous infusion of 2 mg [middle dot] kg-1 [middle dot] h-1 intraoperatively and 1.33 mg [middle dot] kg-1 [middle dot] h-1 for 24 h postoperatively) or an equal volume of saline. All patients received similar intensive postoperative rehabilitation. Postoperative pain scores, opioid consumption, and fatigue scores were measured. Times to first flatus, defecation, and hospital discharge were recorded. Postoperative endocrine (cortisol and catecholamines) and metabolic (leukocytes, C-reactive protein, and glucose) responses were measured for 48 h. Data (presented as median [25-75% interquartile range], lidocaine vs. saline groups) were analyzed using Mann-Whitney tests. P < 0.05 was considered statistically significant.
Results: Patient demographics were similar in the two groups. Times to first flatus (17 [11-24] vs. 28 [25-33] h; P < 0.001), defecation (28 [24-37] vs. 51 [41-70] h; P = 0.001), and hospital discharge (2 [2-3] vs. 3 [3-4] days; P = 0.001) were significantly shorter in patients who received lidocaine. Lidocaine significantly reduced opioid consumption (8 [5-18] vs. 22 [14-36] mg; P = 0.005) and postoperative pain and fatigue scores. In contrast, endocrine and metabolic responses were similar in the two groups. 相似文献
A case study is presented in which a focal hand dystonia seems to have developed in the right hand of a classical guitarist as a result of a neuromuscular peripheral defect caused by trauma. The trauma was a near total perforation of the first web space by a splinter. Healing was uneventful without apparent functional complications. Two years later the patient noticed difficulties in extending the index in playing, for which he received various unsuccessful treatments during seven years. However, we found more severe dystonic symptoms (cocontractions) in the thumb than in the index during playing, which correlated with an undiagnosed insufficiency in the flexor pollicis brevis (FPB). This defect allowed proposing a biomechanical analysis of compensations for diminished thumb control in playing, which would explain the dysfunction in the index in playing as overcompensation for the thumb problem. If this analysis is correct, the etiology of the case can be traced back to underlying multiarticular control problems in the thumb caused by an insufficient FPB. This defect was considered irrepairable. It was concluded that even with knowledge of the underlying cause, a potentially successful treatment of the dystonia might not exist in this case. The case would demonstrate that task-specific hand dystonias can arise as overcompensations for (peripheral) neuro-musculoskeletal defects. The case is illustrated by videos of playing and functional thumb tests. 相似文献
PURPOSE: A pseudo forward ray-tracing (PFRT) algorithm is developed to evaluate surface reconstruction in corneal topography. The method can be applied to topographers where one-to-one correspondence between mire and image points can be established. METHODS: The PFRT algorithm was applied on a corneal topographer designed and constructed at the VU University Medical Center, Amsterdam, The Netherlands. Performance of the algorithm was evaluated using artificial test surfaces and two sample eyes. The residual output of the PFRT algorithm is displayed as pixel displacements of actual feature points on the corneal image. Displacement of 1 pixel indicates submicrometer corneal height accuracy. RESULTS: PFRT residual increases with complexity of the measured surface. Using Zernike radial order 6, the mean residual for the artificial surfaces is subpixel. The mean residual for the regular cornea and the irregular cornea is 1.16 and 2.94 respectively. To some extent, increasing the Zernike radial order improves the accuracy. The improvement from order 6 to 20 is factor 2.3 for the irregular cornea. Using the residuals to further improve the accuracy brought local changes as high as 0.28 D in some areas of the reconstructed corneal power map. CONCLUSION: PFRT can be used to evaluate how close a reconstructed corneal surface is to the actual one. The residue information obtained from this algorithm can be displayed simultaneously with the corneal image. This provides accurate information about the corneal shape that is useful for application in laser refractive surgery. 相似文献
A method for producing carrier free 66Ga (T1/2:9.4h; +) by 4He bombardment of natural copper targets is presented. 66Ga is formed by means of the 63Cu (4He, n) 66Ga reaction. Production yields are given in the 17.5 to 8 MeV 4He energy range. Chemical purification of 66Ga from the copper target is described. The only radionuclidic impurity found in the final product was 67Ga. Albumin colloids from commercially available kits designed for use with 99mTc could easily be labeled with 66Ga and employed for studies of the lymphatic system by positron emission tomography. 相似文献
Transient receptor potential (TRP) channels provide an enormous variability of Ca(2+) influx mechanisms triggered by a wide range of stimuli. In this review, we discuss the activation properties of the Ca(2+)- and Mg(2+)-permeable TRP channel of the vanilloid subfamily TRPV4. This channel is activated by various physical and chemical stimuli, such as cell swelling, heat, phorbols and, probably, by endogenous ligands, which are able to induce Ca(2+) entry. Not much is known about the regulation of this channel. We will refer only to a mechanism of Ca(2+)-dependent inhibition of TRPV4. Possible functional roles of this channel will be correlated with its observed expression pattern. Finally, we discuss the structural determinants of TRPV4 channel function. 相似文献