Imaging Approach to the Diagnosis of Acute Appendicitis in a Group of Teaching Hospitals With 24/7 In-house Availability of Ultrasound Technologist: Effect of Timing of Request on Imaging Modality.

PURPOSE: The study sought determine effect of requisition timing on the initial-choice imaging modality in appendicitis evaluation. METHODS: This was an institutional review board-approved retrospective study, encompassing 3 University of Toronto teaching hospitals, offering 24/7 radiology coverage. All surgically proven appendicitis cases, from 2012-2014, were included and presurgical ultrasound (US) or computed tomography (CT) reports were analysed. Examinations were all requested by the emergency department, performed by the same technologists and reviewed or finalized by the same radiology group (residents fellows or attending). Two coverage categories, namely regular hours (8 am-5 pm, Monday-Friday) or after hours (5 pm-8 am, Monday-Friday and weekends) were compared. The percentage of the starting modality (US or CT), the rate of CT following an indeterminate US, and the sensitivity of each modality was compared between the 2 categories, utilising Mann-Whitney U and chi-square tests. RESULTS: Presurgical US or CT studies of 494 patients, from February 2012-August 2014, were evaluated. Regular-hours and after-hours coverage demonstrated 174 (89:85 women:men) and 320 (141:179 women:men; P < .04) patients. The average age, 37.9 ± 17.1 women versus 35.2 ± 13.7 men was not statistically different (P = .8). Regular hours included 89 of 174 (51.1%) of US-only examinations, 50 of 174 (29%) of CT-only examinations, and 35 of 174 (20%) of US examinations followed by CT examinations. After hours included 147 of 320 (46%) of US-only examinations, 147 of 320 (46%) of CT-only examinations, and 26 of 320 (8%) of US examinations followed by CT examinations (P < .001). The total diagnostic sensitivities for US and CT were 86% (81% regular hours, 90% after hours; P = .041) and 99.2% (100% regular hours, 99% after hours; P > .05), respectively. CONCLUSIONS: US was less utilised in acute appendicitis detection after hours, although its diagnostic sensitivity was better than regular-hours coverage.

Vitrification of intact human articular cartilage.

Articular cartilage injuries do not heal and large defects result in osteoarthritis with major personal and socioeconomic costs. Osteochondral transplantation is an effective treatment for large joint defects but its use is limited by the inability to store cartilage for long periods of time. Cryopreservation/vitrification is one method to enable banking of this tissue but decades of research have been unable to successfully preserve the tissue while maintaining cartilage on its bone base - a requirement for transplantation. To address this limitation, human knee articular cartilage from total knee arthroplasty patients and deceased donors was exposed to specified concentrations of 4 different cryoprotective agents for mathematically determined periods of time at lowering temperatures. After complete exposure, the cartilage was immersed in liquid nitrogen for up to 3 months. Cell viability was 75.4 ± 12.1% determined by membrane integrity stains and confirmed with a mitochondrial assay and pellet culture documented production of sulfated glycosaminoglycans and collagen II similar to controls. This report documents successful vitrification of intact human articular cartilage on its bone base making it possible to bank this tissue indefinitely.

Analysis of time-dependent adaptations in whole-body energy balance in obesity induced by high-fat diet in rats.

BACKGROUND: High-fat (HF) diet has been extensively used as a model to study metabolic disorders of human obesity in rodents. However, the adaptive whole-body metabolic responses that drive the development of obesity with chronically feeding a HF diet are not fully understood. Therefore, this study investigated the physiological mechanisms by which whole-body energy balance and substrate partitioning are adjusted in the course of HF diet-induced obesity. METHODS: Male Wistar rats were fed ad libitum either a standard or a HF diet for 8 weeks. Food intake (FI) and body weight were monitored daily, while oxygen consumption, respiratory exchange ratio, physical activity, and energy expenditure (EE) were assessed weekly. At week 8, fat mass and lean body mass (LBM), fatty acid oxidation and uncoupling protein-1 (UCP-1) content in brown adipose tissue (BAT), as well as acetyl-CoA carboxylase (ACC) content in liver and epidydimal fat were measured. RESULTS: Within 1 week of ad libitum HF diet, rats were able to spontaneously reduce FI to precisely match energy intake of control rats, indicating that alterations in dietary energy density were rapidly detected and FI was self-regulated accordingly. Oxygen consumption was higher in HF than controls throughout the study as whole-body fat oxidation also progressively increased. In HF rats, EE initially increased, but then reduced as dark cycle ambulatory activity reached values ~38% lower than controls. No differences in LBM were detected; however, epidydimal, inguinal, and retroperitoneal fat pads were 1.85-, 1.89-, and 2.54-fold larger in HF-fed than control rats, respectively. Plasma leptin was higher in HF rats than controls throughout the study, indicating the induction of leptin resistance by HF diet. At week 8, UCP-1 content and palmitate oxidation in BAT were 3.1- and 1.5-fold higher in HF rats than controls, respectively, while ACC content in liver and epididymal fat was markedly reduced. CONCLUSION: The thermogenic response induced by the HF diet was offset by increased energy efficiency and time-dependent reduction in physical activity, favoring fat accumulation. These adaptations were mainly driven by the nutrient composition of the diet, since control and HF animals spontaneously elicited isoenergetic intake.