Jane Holland

Quantitative intracellular cytokine measurement: age-related changes in proinflammatory cytokine production

The proinflammatory cytokines play a central role in mediating cellular and physiological responses, and levels may reflect immune system effectiveness. In this study, the effect of ageing on the inflammatory response was examined using a novel method to detect production of the proinflammatory cytokines, i.e. tumour necrosis factor‐alpha (TNF‐α), IL‐6 and IL‐1β. Peripheral blood mononuclear cells (PBMC) obtained from healthy donors of different ages were incubated for 0, 24, 48 and 72 h with or without phorbol 12‐myristate 13‐acetate (PMA) stimulation. At each time point these cells were permeabilized and incubated with secondary conjugated FITC MoAbs specific for each cytokine. A flow cytometric system was developed to quantify specific intracellular fluorescence in T cells (CD3+) and monocytes (CD14+). TNF‐α, IL‐6 and IL‐1β production in cell culture supernatants was also measured using ELISAs. In older subjects, flow cytometry detected significant increases in intracellular T cell TNF‐α and IL‐6 (P < 0.05). IL‐1β was not detected in any of the T cell samples. Likewise, the monocytes of older subjects demonstrated increased intracellular levels of all three cytokines, but these increases were not significant (P > 0.05). These changes in intracellular proinflammatory cytokine levels may explain some of the exaggerated inflammatory responses seen in elderly patients.

Laparoscopically assisted reversal of Hartmann's procedure revisited.

Reversal of Hartmanns procedure is a major operation, associated with substantial morbidity and mortality. In light of this, many patients elect not to undergo reversal (44–49%). In recent years, enthusiasm for laparoscopic reversal of Hartmanns procedure has increased, with the outcomes of many series suggesting that it has a reduced morbidity and mortality compared with the open procedure. We present our initial experience of four cases of laparoscopically assisted reversal of Hartmanns procedure and review the literature on this technique. Laparoscopic reversal was successful in all but one case. Literature review shows reduced postoperative hospital stay compared with the traditional, open approach and suggests that laparoscopic reversal is associated with lower morbidity and mortality rates. Laparoscopic reversal of Hartmanns procedure is feasible with potential advantages for the patient.

Subchondral trabecular structural changes in the proximal tibia in an ovine model of increased bone turnover

Ovariectomized (OVX) sheep are now considered to be useful models for a variety of metabolic bone disorders. The specific aim of this study was to determine the effects of ovariectomy on the structural parameters and material density of the subchondral bone of the ovine tibial plateau as measured by microcomputed tomography (MicroCT). Twenty‐three sheep were examined in this study; 10 of the sheep underwent ovariectomy (OVX), and the remainder (n = 13) were kept as controls (CON). These animals were then sacrificed at 12 months post‐operatively. Three‐dimensional analyses were performed of osteochondral samples (15 mm deep) which were obtained from the medial tibial plateau using MicroCT. Bone volume fraction of the subchondral trabecular bone was reduced in the ovariectomized sheep as compared to control animals (0.439 vs. 0.483, P = 0.038). Trabeculae were also significantly thinner in the OVX group (0.220 vs. 0.252 mm, P = 0.010), with reduced connectivity density (7.947 vs. 11.524 mm−3, P = 0.014). There was a trend towards lower numbers of individual trabeculae present in the OVX group as compared to controls, but this did not reach significance (2.817 vs. 3.288 mm−1, P = 0.1). There was also increased trabecular separation in the OVX group, which again fell short of significance (0.426 vs. 0.387 mm, P = 0.251). There was no difference in hydroxyapatite concentration (HA) between the two groups (929 vs. 932 mgHA cm−3, P = 0.687). In conclusion, significant alterations of the trabecular architecture under the tibial plateau were observed following 12 months of oestrogen‐deficiency in this ovine model. Despite these marked morphological and structural density differences, the material densities were equal in the two groups.

Is a picture worth a thousand words: an analysis of the difficulty and discrimination parameters of illustrated vs. text-alone vignettes in histology multiple choice questions

BackgroundAdvances in cognitive load theory have led to greater understanding of how we process verbal and visual material during learning, but the evidence base with regard to the use of images within written assessments is still sparse. This study examines whether the inclusion of images within the stimulus format of multiple choice questions (MCQs) has a predictable or consistent influence on psychometric item properties, such as difficulty or discrimination.MethodsItem analysis data from three consecutive years of histology multiple choice examinations were included in this study. All items were reviewed and categorised according to whether their stem, or stimulus format, was purely textual or included an associated image.ResultsA total of 195 MCQs were identified for inclusion and analysed using classical test theory; 95 used text alone and 100 included an image within the question stem. The number of students per examination ranged from 277 to 347, with a total of 60,850 student-question interactions. We initially examined whether the inclusion of an image within the item stem altered the item difficulty using Mann–Whitney U. The median item difficulty for images with purely textual stems was 0.77, while that for items incorporating an appropriate image was 0.80; this difference was not significant (0.77 vs. 0.80; p = 0.862, Mann–Whitney-U = 4818.5). Mean values showed that the Item Discrimination Index appeared unaffected by the inclusion of an image within the stem, and Item point biserial correlation also showed no difference in means between these two groups (Independent samples t-test; 2-tailed).ConclusionWe demonstrate that the addition of illustrations within undergraduate histology Multiple Choice Question stems has no overall influence on item difficulty, or measures of item discrimination. We conclude that the use of images in this context is statistically uncritical, and suggest that their inclusion within item stems should be based upon the principles of constructive alignment. However, further research with respect to the effect of images within item stems on cognitive processing, particularly with regard to image complexity or type, would enable the development of more informed guidelines for their use.

Examination of osteoarthritis and subchondral bone alterations within the stifle joint of an ovariectomised ovine model

The exact relationship between osteoporosis and osteoarthritis is still a matter for debate for many. The ovariectomised ewe is frequently used as a model for osteoporosis, resulting in significant alterations in bone morphometry and turnover in both trabecular and subchondral bone after 1 year. This study examines whether ovariectomy has any impact on development of osteoarthritis within the ovine stifle joint at the same time point. In addition, we investigate whether there are any significant correlations present between articular cartilage degeneration and alterations in microstructural parameters or turnover rates in the underlying bone. Twenty‐two sheep were examined in this study; 10 of the sheep underwent ovariectomy and 12 were kept as controls. Five distinctive fluorochrome dyes were administered intravenously at 12‐week intervals to both groups, to label sites of bone turnover. All animals were then sacrificed 12 months postoperatively. Although most specimens showed some evidence of osteoarthritis, no measurable difference between the two study groups was detected. Osteoarthritis was associated with a thinning of the subchondral plate, specifically the subchondral cortical bone; however, whereas previous studies have suggested a link between trabecular thinning and osteoarthritis, this was not confirmed. No correlation was found between osteoarthritis and bone turnover rates of either the subchondral trabecular bone or bone plate. In conclusion, despite the fact that ovariectomy results in marked morphological and structural changes in the ovine stifle joint at 1‐year postoperatively, no evidence was found to suggest that it plays a direct role in the aetiology of osteoarthritis.

Subchondral osteopenia and accelerated bone remodelling post-ovariectomy - a possible mechanism for subchondral microfractures in the aetiology of spontaneous osteonecrosis of the knee?

Osteopenia and subchondral microfractures are implicated in the aetiology of spontaneous osteonecrosis of the knee (SPONK). The ovine tibia shows significant alterations of the trabecular architecture within the subchondral bone of the medial tibial plateau post‐ovariectomy (OVX), including reduced trabecular bone volume fraction. We hypothesise that accelerated subchondral bone resorption may also play a role in increasing microfracture risk at this site. Twenty‐two sheep were examined in this study; 10 of the sheep underwent OVX, while the remainder (n = 13) were kept as controls (CON). Five fluorochrome dyes were administered intravenously at 12‐week intervals via the jugular vein to both groups, to label sites of bone turnover. These animals were then killed at 12 months post‐operatively. Bone turnover was significantly increased in the OVX group in both trabecular bone (2.024 vs. 1.047 no. mm−2; P = 0.05) and within the subchondral bone plate (4.68 vs. 0.69 no. mm−2; P < 0.001). In addition to the classically described turnover visible along trabecular surfaces, we also found visual evidence of intra‐trabecular osteonal remodelling. In conclusion, this study shows significant alterations in bone turnover in both trabecular bone and within the subchondral bone plate at 1 year post‐OVX. Remodelling of trabecular bone was due to both classically described hemi‐osteonal and intra‐trabecular osteonal remodelling. The presence of both localised osteopenia and accelerated bone remodelling within the medial tibial plateau provide a possible mechanism for subchondral microfractures in the aetiology of SPONK. Further utilisation of the OVX ewe may be useful for further study in this field.

Out of sight, out of mind: Do repeating students overlook online course components?

E‐Learning is becoming an integral part of undergraduate medicine, with many curricula incorporating a number of online activities and resources, in addition to more traditional teaching methods. This study examines physical attendance, online activity, and examination outcomes in a first‐year undergraduate medical program. All 358 students who completed the Alimentary System module within the first semester of the program were included, 30 of whom were repeating the year, and thus the module. This systems‐based, multidisciplinary module incorporated didactic lectures, cadaveric small group tutorials and additional e‐Learning resources such as online histology tutorials. Significant differences were demonstrated in physical attendance and utilization of online resources between repeating students and those participating in the module for the first time. Subsequent analyses confirmed that physical attendance, access of online lecture resources, and utilization of online histology tutorials were all significantly correlated. In addition, both physical attendance and utilization of online resources significantly correlated with summative examination performance. While nonattendance may be due to a variety of factors, our data confirm that significant differences exist in both physical attendance and online activity between new entrants and repeating students, such that all students repeating a module or academic year should be routinely interviewed and offered appropriate supports to ensure that they continue to engage with the program. While the development of complex algorithmic models may be resource intensive, using readily available indices from virtual learning environments is a straightforward, albeit less powerful, means to identify struggling students prior to summative examinations. Anat Sci Educ 9: 555–564.