Alzheimer's disease (AD) affects memory and neurogenesis. Adult neurogenesis plays an important role in memory function and impaired neurogenesis contributes to cognitive deficits associated with AD. Increased physical/ cognitive activity is associated with both reduced risk of dementia and increased neurogenesis. Previous attempts to restore hippocampal neurogenesis in transgenic mice by voluntary running (RUN) and environmental enrichment (ENR) provided controversial results due to lack of non-transgenic (non-Tg) control and inclusion of social isolation as "standard" housing environment. Here, we determine the effect of RUN and ENR upon hippocampal neurogenesis in a triple transgenic (3xTg-AD) mouse model of AD, which mimics AD pathology in humans. We used single and double immunohistochemistry to determine the area density of hippocampal proliferating cells, measured by the presence of phosphorylated Histone H3 (HH3), and their potential neuronal and glial phenotype by co-localizing the proliferating cells with the immature neuronal marker doublecortin (DCX), mature neuronal marker (NeuN) and specific astroglial marker (GFAP). Our results show that 3xTg-AD mice in control environment exhibit impaired hippocampal neurogenesis compared to non-Tg animals at 9 months of age. Exposure to RUN and ENR housing restores hippocampal neurogenesis in 3xTg-AD animals to non-Tg control levels. Differentiation into neurones and glial cells is affected neither by transgenic status nor by housing environment. These results suggest that hippocampus of 3xTg-AD animals maintains the potential for cellular plasticity. Increase in physical activity and/or cognitive experience enhances neurogenesis and provides a potential for stimulation of cognitive function in AD.

BACKGROUND Three-dimensional (3D) modelling technology translates the patient-specific anatomical information derived from two-dimensional radiological images into virtual or physical 3D models, which more closely resemble the complex environment encountered during surgery. It has been successfully applied to surgical planning and navigation, as well as surgical training and patient education in several surgical specialties, but its uptake lags behind in colorectal surgery. Rectal cancer surgery poses specific challenges due to the complex anatomy of the pelvis, which is difficult to comprehend and visualise. AIM To review the current and emerging applications of the 3D models, both virtual and physical, in rectal cancer surgery. METHODS Medline/PubMed, Embase and Scopus databases were searched using the keywords “rectal surgery”, “colorectal surgery”, “three-dimensional”, “3D”, “modelling”, “3D printing”, “surgical planning”, “surgical navigation”, “surgical education”, “patient education” to identify the eligible full-text studies published in English between 2001 and 2020. Reference list from each article was manually reviewed to identify additional relevant papers. The conference abstracts, animal and cadaveric studies and studies describing 3D pelvimetry or radiotherapy planning were excluded. Data were extracted from the retrieved manuscripts and summarised in a descriptive way. The manuscript was prepared and revised in accordance with PRISMA 2009 checklist. RESULTS Sixteen studies, including 9 feasibility studies, were included in the systematic review. The studies were classified into four categories: feasibility of the use of 3D modelling technology in rectal cancer surgery, preoperative planning and intraoperative navigation, surgical education and surgical device design. Thirteen studies used virtual models, one 3D printed model and 2 both types of models. The construction of virtual and physical models depicting the normal pelvic anatomy and rectal cancer, was shown to be feasible. Within the clinical context, 3D models were used to identify vascular anomalies, for surgical planning and navigation in lateral pelvic wall lymph node dissection and in management of recurrent rectal cancer. Both physical and virtual 3D models were found to be valuable in surgical education, with a preference for 3D printed models. The main limitations of the current technology identified in the studies were related to the restrictions of the segmentation process and the lack of 3D printing materials that could mimic the soft and deformable tissues. CONCLUSION 3D modelling technology has potential to be utilised in multiple aspects of rectal cancer surgery, however, it is still at the experimental stage of application in this setting.

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Aim The continent ileostomy allows evacuation of an ileal reservoir at a time convenient to the patient. It is a surgical option for patients with ulcerative colitis (UC) when a restorative option is not suitable or has not succeeded and the patient does not want a conventional end ileostomy. Continent ileostomy types include the Kock pouch, Barnett continent intestinal reservoir and T‐pouch. All of the published evidence on the long‐term outcome and quality of life after continent ileostomy for UC was systematically reviewed. Methods A systematic review was performed in line with the Preferred Reporting Items for Systematic Reviews and Meta‐Analyses (PRISMA) guidelines. Studies published between 1990 and 2020 were included. A descriptive synthesis was used due to the clinical heterogeneity. Results The search returned 1655 abstracts and after screening of abstracts and full text review, 19 were included in the final review, involving 1602 patients. Operative mortality is low (0%–3.6%) after all types of continent ileostomy but reoperation rates are high (20.8%–65%) because of valve mechanism failures. Rates of fistulae (0%–25.5%) and stomal stenosis (0%–25%) can be relatively high postoperatively. Quality of life scores improve for most patients undergoing continent ileostomy, especially for patients converted from ileal pouch anal anastomosis. Overall, continent ileostomy retention is high in the long‐term. Discussion In the long‐term, patients report high satisfaction and a good quality of life with continent ileostomy, despite high reoperation rates and complications. Newer technologies may reinvigorate interest in the continent ileostomy for this population.