A new teaching model for resident training in regional anesthesia

The adequacy of resident education in regional anesthesia is of national concern. A teaching model to improve resident training in regional anesthesia was instituted in the Anesthesiology Residency in 1996 at Duke University Health System. The key feature of the model was the use of a CA-3 resident in the preoperative area to perform regional anesthesia techniques. We assessed the success of the new model by comparing the data supplied by the Anesthesiology Residency to the Residency Review Committee for Anesthesiology for the training period July 1992-June 1995 (pre-model) and the training period July 1998-June 2001 (post-model). During the 3-yr training period, the pre-model CA-3 residents (n = 12) performed a cumulative total of 80 (58-105) peripheral nerve blocks (PNBs), 66 (59-74) spinal anesthetics, and 133 (127-142) epidural anesthetics. The CA-3 post-model residents (n = 10) performed 350 (237-408) PNBs, 107 (92-123) spinal anesthetics, and 233 (221-241) epidural anesthetics (P < 0.0001). All results are reported as median (interquartile range). We conclude that our new teaching model using our CA-3 residents as block residents in the preoperative area has increased their clinical exposure to PNBs. IMPLICATIONS: Inadequate exposure to peripheral nerve blocks has been a national problem. A teaching model instituted at Duke University Health System has resulted in a fourfold increase in exposure to peripheral nerve blocks compared with the national averages.     

Glomerular size and global glomerulosclerosis in normal Caucasian donor kidneys: effects of aging and gender

BACKGROUND: To assess the effects of aging and gender on glomerular size and global glomerulosclerosis (GS) and evaluate the relationship between glomerular size and GS in normal Caucasian donor kidneys. METHODS: All baseline graft biopsies between 1990 and 1998 were reviewed and sections with tissues containing at least 15 glomeruli were selected for morphometric analyses using a Digital Imaging Analyzer. Glomerular volumes (GV) were measured using the maximal profile area (MPA) method. The frequency of glomeruli with totally sclerotic lesions representing degree of global GS was expressed as a percentage of total number of glomeruli counted. RESULTS: 102 donor specimens (M/F, 46/56; mean age, 37.4 +/- 17.3 yrs) were analyzed showing mean MPA of 27.8 +/- 6.6 (x 10(-3)mm2), mean GV of 3.6 +/- 1.2 (x 10(6)microm3) and mean GS% of 6 +/- 10%. GV was increased with increasing age (r2 = 0.32, p < 0.0001). There was a progressive increase in glomerular size between infancy and adolescence (2-18 years old). The rate of MPA growth over childhood appeared to be linear (n = 13, r2 = 0.66, p = 0.0004). However, MPA increased with age at a slower rate (n = 99, r2 = 0.66, p = 0.0004) in adults (excluding data for patients < 18 years) than in infancy and adolescence. There wasn't significant gender difference in GV. Age (r = 0.47, p < 0.0001) and MPA (r = 0.31, p < 0.05) were both positively correlated with global GS. CONCLUSIONS: 1. Aging contributes to enlargement of glomerular size and global GS. 2. Gender had no significant effect on glomerular size. 3. Enlargement of glomerular size was associated with global GS in normal Caucasians.     

Magnetic resonance imaging accurately tracks kidney pathology and heterogeneity in the transition from acute kidney injury to chronic kidney disease

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Sympathetic Neural Adaptation to Hypocaloric Diet With or Without Exercise Training in Obese Metabolic Syndrome Subjects

OBJECTIVE

Sympathetic nervous system (SNS) overactivity contributes to the pathogenesis and target organ complications of obesity. This study was conducted to examine the effects of lifestyle interventions (weight loss alone or together with exercise) on SNS function.

RESEARCH DESIGN AND METHODS

Untreated men and women (mean age 55 ± 1 year; BMI 32.3 ± 0.5 kg/m²) who fulfilled Adult Treatment Panel III metabolic syndrome criteria were randomly allocated to either dietary weight loss (WL, n = 20), dietary weight loss and moderate-intensity aerobic exercise (WL+EX, n = 20), or no treatment (control, n = 19). Whole-body norepinephrine kinetics, muscle sympathetic nerve activity by microneurography, baroreflex sensitivity, fitness (maximal oxygen consumption), metabolic, and anthropometric measurements were made at baseline and 12 weeks.

RESULTS

Body weight decreased by −7.1 ± 0.6 and −8.4 ± 1.0 kg in the WL and WL+EX groups, respectively (both P < 0.001). Fitness increased by 19 ± 4% (P < 0.001) in the WL+EX group only. Resting SNS activity decreased similarly in the WL and WL+EX groups: norepinephrine spillover by −96 ± 30 and −101 ± 34 ng/min (both P < 0.01) and muscle sympathetic nerve activity by −12 ± 6 and −19 ± 4 bursts/100 heart beats, respectively (both P < 0.01), but remained unchanged in control subjects. Blood pressure, baroreflex sensitivity, and metabolic parameters improved significantly and similarly in the two lifestyle intervention groups.

CONCLUSIONS

The addition of moderate-intensity aerobic exercise training to a weight loss program does not confer additional benefits on resting SNS activity. This suggests that weight loss is the prime mover in sympathetic neural adaptation to a hypocaloric diet.The metabolic syndrome (MetS) is an increasingly prevalent multidimensional risk factor for cardiovascular disease and type 2 diabetes (1). Its etiology is complex and incompletely understood, but thought to involve the interplay between metabolic susceptibility, lifestyle factors, and the acquisition of excess visceral adiposity (2). Scientific studies performed over the last 2 decades strongly support the relevance of the sympathetic nervous system (SNS) in both the pathogenesis and target organ complications of MetS obesity (3).Several indexes of SNS activity, such as urinary norepinephrine excretion, norepinephrine spillover from sympathetic nerves, and postganglionic muscle sympathetic nerve activity (MSNA) are increased in subjects with MetS, even in the absence of hypertension (4–7). Among the adiposity indexes, abdominal visceral fat is most strongly associated with elevated MSNA (8). Because of the bidirectional relationship between sympathetic activation and insulin resistance, much debate has focused on their chronology. Prospective studies with 10–20 years follow-up indicate that elevated plasma norepinephrine concentration (9) and sympathetic reactivity (10) precede and predict future rise in BMI and development of insulin resistance. Although seemingly counterintuitive, sympathetic activation may be causally linked to obesity via β-adrenoceptor desensitization (11) and insulin resistance (12,13). In established obesity, metabolic, cardiovascular (baroreflex impairment), and medical conditions (obstructive sleep apnea) contribute significantly to sympathetic neural drive and further aggravate insulin resistance, hence establishing a vicious cycle (3,7). Chronic sympathetic activation is associated with an increased prevalence of preclinical cardiovascular and renal changes that are recognized predictors of adverse clinical prognosis (3,14,15).Weight loss and exercise are recommended as first-line treatments for MetS. The Diabetes Prevention Program and the Oslo Diet and Exercise Study have shown the marked clinical benefits of intensive lifestyle intervention on the resolution of the MetS (16,17). Individually, both weight loss (5) and exercise training (18,19) cause sympathoinhibition and improvement in MetS components. We have previously reported that moderate weight loss (7% of body weight) by diet alone is accompanied by reductions in whole-body norepinephrine spillover and MSNA and improvement in spontaneous cardiac baroreflex function in middle-aged MetS subjects (5). Because exercise is often added to energy restriction in the treatment of obesity, it is pertinent to clarify its additive benefits. Augmented improvements in metabolic, anthropometric, and cardiovascular parameters have been observed after combined exercise training and dietary weight loss in some (17,20,21), but not other studies (22), and there are limited data regarding their combined effect on sympathetic activity (23). Exercise training may potentially augment weight loss induced sympathoinhibition by promoting a greater loss of fat relative to lean mass (20,21), by further improvement in insulin sensitivity (24) and reduction in plasma leptin concentration (21), and by potentiation of baroreceptor sensitivity (18).The present study was conducted to 1) test the hypothesis that weight loss by combined hypocaloric diet and aerobic exercise training would be associated with greater sympathoinhibition and improvement in MetS components than hypocaloric diet alone and 2) to examine the interrelationships between reduction in sympathetic tone and concurrent changes in anthropometric, metabolic (insulin sensitivity, plasma leptin concentration), and cardiovascular parameters. A moderate-intensity bicycle riding protocol was chosen as the exercise intervention, based on an earlier study that demonstrated attenuation in whole-body and renal norepinephrine spillover rates with this regimen in healthy men (19).     

Effect of portal hypertension onIn Vivo bile acid-mediated small intestinal mucosal injury in the rat

This study's purpose was to determine whether portal hypertension adversely affects small intestinal mucosal injury. Portal hypertension was produced in male Sprague-Dawley rats by two-stage ligation of the portal vein. Sham-operated rats were used as controls. Two weeks later, intestinal injury was produced byin vivo perfusion with 5 mM chenodeoxycholic acid for 30 min. Intestinal injury was assessed by quantitative morphometry and by measuring intestinal water and mannitol absorption. Portal hypertension resulted in more injury in the distal perfused intestine as manifested by increased villus tip denudation [portal hypertensive 52.5±9.6sem) vs controls 28.1±5.7m, P=0.05). Additionally there was a significant decrease in the unperfused duodenal villus height in portal hypertensive rats (portal hypertensive 755±22 vs controls 848±28m, P<0.02). Portal hypertension had no significant effect on the increase in mannitol absorption or water secretion caused by chenodeoxycholic acid perfusion. This study suggests that portal hypertension alters small intestinal mucosa and increases susceptibility to injury.This work was supported in part by a grant from the Research Service of the Veterans Administration.     

SGLT2 inhibition attenuates arterial dysfunction and decreases vascular F-actin content and expression of proteins associated with oxidative stress in aged mice

GeroScience - Aging of the vasculature is characterized by endothelial dysfunction and arterial stiffening, two key events in the pathogenesis of cardiovascular disease (CVD). Treatment with sodium...     

Utility of Web-based assessment of patient satisfaction with endoscopy

OBJECTIVES: The dramatic growth of the World Wide Web (Web) holds potential for use in survey distribution and submission. Its use has not previously been studied in the context of patient satisfaction with endoscopy procedures. In this study we compared standard mail, telephone, and Web-based modes of endoscopy satisfaction survey administration with respect to response rate and response content. METHODS: An endoscopy satisfaction questionnaire consisting of seven core items from the modified Group Health Association of America (GHAA-9) was distributed to patients after routine outpatient endoscopy. Patients were randomized to receive the questionnaire by standard mail, telephone, or Web (if applicable). Response rates and satisfaction scores in the groups were compared. The nonresponders to the standard mail and Web surveys were subsequently contacted by telephone to determine their level of satisfaction. RESULTS: Response rates to the telephone survey (81% among those designated as non-Web users and 78% among Web users) and standard mail (75% non-Web users, 67% Web users) were higher than response rate to the Web-based survey (34%) (p < or = 0.0005). There was no significant difference in satisfaction scores among the groups or between satisfaction of nonresponders and responders. CONCLUSIONS: The potential of our Web-based survey was limited by poor response rates. This arose from privacy protection precautions that complicated access to the Web site. Future Web-based strategies for surveying patients will need to be more user-friendly while maintaining the intent of the recent Health Insurance Portability and Accountability Act regulations.     

Endoscopic ultrasound for rectal cancer

The application of EUS has improved the way we evaluate and manage patients with rectal cancer. EUS has substantially greater sensitivity than CT in detecting advanced T stage tumors. Such improved sensitivity results in changes in preoperative therapy that would not otherwise have occurred without EUS. Although the addition of FNA provides little incremental effect on patient management, it carries the most potential for impacting management in those patients with early T stage disease, and its use should be considered in this subgroup of patients. Whether the accurate staging ability of EUS translates into improved outcomes in terms of reduced recurrence rates and ultimately prolonged survival remains uncertain. This will require further long-term outcome studies focusing on the endpoint of tumor recurrence and patient survival.     

Microvascular function at the margins of early experimental myocardial infarcts in isolated rabbit hearts

Summary Injection of low-viscosity resin was used to identify in situ functional blood vessels at the margins of developing regional myocardial infarcts. The ventral interventricular branch (VIB) of the left coronary artery was occluded for 0–240 min in 20 isolated perfused rabbit hearts. After perfusion fixation with glutaraldehyde, resin was injected into the coronary arteries—that injected into the VIB contained dispersed lead dioxide and that injected into the remainder of the heart contained Fat Red 7B dye. This allowed macroscopic and microscopic identification of functional blood vessels. Following transmural freeze fracture, left ventricles were examined using back-scattered electron imaging in a scanning electron microscope. Close to 60% of capillaries in nonischemic myocardium allowed the passage of resin. Thirty minutes of ischemia produced a hyperemic increase to 80%–90% in the proportion of filled vessels. After 60 min, however, a severe reperfusion defect corresponding to the no-reflow phenomenon had developed, with virtually all vessels collapsed and <10% functional. Among the structurally normal myocytes adjacent to the infarct margin there was a significant reduction (to 30%–40%) in the proportion of functional capillaries. This was due to groups of dilated vessels which were not accessible to arterial supply. Although these marginal low-flow regions were of small volume at any one point in time, they seem likely to contribute to the progression of ischemic necrosis, and are probably nonfunctional due to the compression of their venous drainage traversing the infarct.This research was supported by grants from the Medical Research Council of New Zealand and the National Heart Foundation of New Zealand.     

Sequence Conservation of the Region Targeted by the Abbott RealTime HBV Viral Load Assay in Clinical Specimens

The Abbott RealTime HBV assay targets the N-terminal region of the S gene. Here we analyzed the sequence variability of the assay target region from >2,100 clinical specimens. Thermodynamic modeling of the percentage of bound primer/probe at the assay annealing temperature was performed to assess the potential effect of sequence variability.