Cellulose: A Review of Water Interactions, Applications in Composites, and Water Treatment.

Cellulose is known to interact well with water, but is insoluble in it. Many polysaccharides such as cellulose are known to have significant hydrogen bond networks joining the molecular chains, and yet they are recalcitrant to aqueous solvents. This review charts the interaction of cellulose with water but with emphasis on the formation of both natural and synthetic fiber composites. Covering studies concerning the interaction of water with wood, the biosynthesis of cellulose in the cell wall, to its dispersion in aqueous suspensions and ultimately in water filtration and fiber-based composite materials this review explores water-cellulose interactions and how they can be exploited for synthetic and natural composites. The suggestion that cellulose is amphiphilic is critically reviewed, with relevance to its processing. Building on this, progress made in using various charged and modified forms of nanocellulose to stabilize oil-water emulsions is addressed. The role of water in the aqueous formation of chiral nematic liquid crystals, and subsequently when dried into composite films is covered. The review will also address the use of cellulose as an aid to water filtration as one area where interactions can be used effectively to prosper human life.

Smoking status predicts anastomotic leak after esophagectomy: a systematic review & meta-analysis.

BACKGROUND: Anastomotic leak after esophagectomy is a major contributor to surgery-related morbidity and mortality. The purpose of this systematic review was to evaluate if positive-smoking status is associated with the incidence of this complication. METHODS: A systematic search of MEDLINE, EMBASE, Scopus, Web of Science and Cochrane Library was performed on April 4th, 2023. Inclusion criteria comprised human participants undergoing esophagectomy, age ≥ 18, n ≥ 5, and identification of smoking status. The primary outcome was incidence of anastomotic leak. Sub-group analysis by ex- or current smoking status was performed. Meta-analysis was performed with RevMan 5.4.1 using a Mantel-Haenszel random-effects model. Publication bias was evaluated visually with funnel plots and through the Egger test. RESULTS: A total of 220 abstracts were screened, of which 69 full-text studies were assessed for eligibility, with 13 studies selected for final inclusion. This included 16,103 patients, of which 4433 were ex- or current smokers, and 9141 were never smokers. Meta-analysis revealed an increased odds of anastomotic leak in patients with a positive-smoking status (current or ex-smokers) compared to never smokers (OR 1.44, 95% CI 1.18-1.76, I2 = 44%, p < 0.001. Meta-analysis of six studies comparing active smokers alone to never smokers identified a significant increased odds of anastomotic leak (OR 1.80, 95% CI 1.25-2.59, p = 0.002, I2 = 0%). Meta-analysis of five studies comparing ex-smokers to never smokers identified a significant increased odds of anastomotic leak (OR 1.36, 95% CI 1.02-1.82, p = 0.04, I2 = 0%). The odds of anastomotic leak decreased among ex-smokers compared to active smokers. CONCLUSION: The findings of this systematic review and meta-analysis support the association between positive-smoking status and the risk of anastomotic leak after esophagectomy. Results further emphasize the importance of preoperative smoking cessation to reduce post-operative morbidity.

Race and sex diversity in Canadian academic surgical societies.

BACKGROUND: It is vital for national professional surgical societies to embrace diversity, inclusion, and equity. This study examines race and sex diversity in two Canadian surgical societies. METHODS: Websites of the Canadian Society of Cardiac Surgeons (CSCS) and the Canadian Association of General Surgeons (CAGS) and previous programs of their annual meetings were reviewed. Leadership positions, conference speakers, and award winners were categorized by race and sex. RESULTS: White males made up the largest category of Cardiac Surgery meeting speakers (73/142 [51%]), CAGS committee members (89/198 [45%]), CAGS past presidents (38/43 [88%]), and General Surgery meeting speakers (841/1472 [57%]). Of the 17 members that made up the CSCS board of directors and officers, 8 were White males (47%), 5 were BIPOC males (29%), 3 were White females (18%), and 1 was a BIPOC female (6%). Of the 42 members of the CAGS board of directors and advisory committee, 16 were White males (38%), 5 were BIPOC males (12%), 17 were White females (40%), and 4 were BIPOC females (10%). CONCLUSIONS: BIPOC individuals and females are underrepresented in both societies compared to White males. However, in CAGS, improvements in representation can be seen in recent years. It is important that both of these organizations continue to embrace diversity.

Conflict of interest disclosure by US cardiothoracic surgeons.

BACKGROUND: Surgeon-industry collaboration is a key driver of advancement in surgical technology and practice. Disclosures of financial relationships between investigators and industries are important to ensure transparent and critical evaluation of literature. METHODS: All American cardiothoracic (CT) surgeons who published in three major CT surgery journals in 2019 were identified. Whether these surgeons disclosed any conflicts of interest was recorded and compared to actual payments received within 5 years of publication as reported by the Centers for Medicare and Medicaid Services data. RESULTS: In the study period, there were 1079 unique manuscripts involving 885 American CT surgeons as authors, which combined for 2719 author instances. Of these, 96.2% of authors (851 of 885) received payments from companies. The authors who received payments produced 2651 author instances (97.4%). Financial disclosure was reported in only 11.4% (301 of 2651) of these instances. In total, 851 surgeons received more than $187 million over 5 years, with the highest-paid surgeon receiving an average of over $5.9 million per year. The largest individual payments were from "Associated Research Funding," with over $115 million being paid to 277 surgeons over 5 years. The top paying company issued over $96.5 million to American CT surgeons over 5 years. CONCLUSIONS: Nearly all the reviewed publications in three top CT surgery journals were by surgeons who received payments from companies, but very few of these payments were recorded as potential conflicts of interest. A more consistent and robust policy of COI disclosure is needed to reduce perceptions of bias.

Increased team familiarity for surgical time savings: Effective primarily in complex surgical cases.

BACKGROUND: Cohesion between team members is critical for surgical performance. Our previous study has shown that the experience of working together (measured by Team Familiarity Score, TFS) helps reduce procedure time (PT). However, that conclusion was found in a relatively small sample size. With a large dataset including mixed general surgical procedures, we hypothesize that team familiarity makes a significant contribution to the improvement of team performance in complex cases, rather than in medium or basic surgical cases, measured by the procedure time, length of hospital stays (LOS), and surgical cost (COST). STUDY DESIGN: Patient demographics, operation, and patient outcome data of 922 general surgery cases were included. The cases were divided into three subgroups, including basic, medium, and complex surgical procedures. TFS and an Index of Difficulty of Surgery (IDS) were calculated for each procedure. Simple linear regression and random forest regressions were performed to analyze the association between surgical outcomes and all included independent variables (TFS, IDS, patient age, patient weight, and team size). RESULTS: When applied to complex cases, procedure time (r = -0.21) and cost (r = -0.23) dropped as TFS increases. In basic and medium surgical cases, increasing team familiarity failed to shorten the procedure time on average. CONCLUSION: Team familiarity is more important in complex cases because there is greater potential for improvement through team collaboration compared to basic and medium cases. Caution will be needed when applying team familiarity scores for examining surgical team performance in large databases with skewed to basic surgical cases.

Changes in Sarcopenia Status Predict Survival Among Patients with Resectable Esophageal Cancer.

BACKGROUND: Sarcopenia is a predictor of survival in patients with esophageal cancer. The objective of this research was to obtain insight into how changes in sarcopenia influence survival in resectable esophageal cancer. PATIENTS AND METHODS: A retrospective cohort of patients with esophageal cancer undergoing tri-modality therapy was selected. Body composition parameters from the staging, post-neoadjuvant, and 1-year surveillance computed tomography (CT) scans were calculated. Overall survival (OS) and disease-free survival (DFS) were evaluated using the Kaplan-Meier method and log-rank test, as well as multivariable Cox-proportional hazards models. RESULTS: Of 141 patients, 118 had images at all three timepoints. The median DFS and OS were 33.2 [95% confidence interval (CI) 19.1-73.7] and 34.5 (95% CI 23.1-57.6) months, respectively. Sarcopenia classified by the staging CT was present in 20 (17.0%) patients. This changed to 45 (38.1%) patients by the post-neoadjuvant scan, and 44 (37.3%) by the surveillance scan. In multivariable analysis, sarcopenia at the post-neoadjuvant scan was significantly associated with OS [hazards ratio (HR) 2.65, 95% CI 1.59-4.40; p < 0.001] and DFS (HR 1.80, 95% CI 1.03-3.13; p = 0.038). The net change in skeletal muscle index was associated with OS (HR 0.93, 95% CI 0.90-0.97; p < 0.001) and DFS (HR 0.94, 95% CI 0.91-0.98; p = 0.001). CONCLUSIONS: Patients who develop sarcopenia as a consequence of skeletal muscle wasting during neoadjuvant therapy are at risk for worse DFS and OS. Patients who have a net loss of muscle over time may be at high risk for early disease recurrence.

A PXY-Mediated Transcriptional Network Integrates Signaling Mechanisms to Control Vascular Development in Arabidopsis.

The cambium and procambium generate the majority of biomass in vascular plants. These meristems constitute a bifacial stem cell population from which xylem and phloem are specified on opposing sides by positional signals. The PHLOEM INTERCALATED WITH XYLEM (PXY) receptor kinase promotes vascular cell division and organization. However, how these functions are specified and integrated is unknown. Here, we mapped a putative PXY-mediated transcriptional regulatory network comprising 690 transcription factor-promoter interactions in Arabidopsis (Arabidopsis thaliana). Among these interactions was a feedforward loop containing transcription factors WUSCHEL HOMEOBOX RELATED14 (WOX14) and TARGET OF MONOPTEROS6 (TMO6), each of which regulates the expression of the gene encoding a third transcription factor, LATERAL ORGAN BOUNDARIES DOMAIN4 (LBD4). PXY signaling in turn regulates the WOX14, TMO6, and LBD4 feedforward loop to control vascular proliferation. Genetic interaction between LBD4 and PXY suggests that LBD4 marks the phloem-procambium boundary, thus defining the shape of the vascular bundle. These data collectively support a mechanism that influences the recruitment of cells into the phloem lineage, and they define the role of PXY signaling in this context in determining the arrangement of vascular tissue.

Sarcopenia in Lung Cancer: A Narrative Review.

It has been over 10 years since the relationship between sarcopenia and lung cancer was first explored. Since then, sarcopenia research has progressed substantially, and the prognostic value of this condition is becoming increasingly apparent. Prior systematic reviews and meta-analyses have established sarcopenia to be negatively associated with disease-free and overall-survival, as well as a major risk factor for post-operative complications. The bulk of the literature has explored sarcopenia in the resectable setting, with less emphasis placed on studies evaluating this condition in advanced disease. In this up-to-date review, an examination of the literature exploring the association between sarcopenia and long-term outcomes in advanced lung cancer is provided. We further explore the association between adverse events of medical therapy and the role of sarcopenia as a predictor of tumor response. Finally, the interventions on sarcopenia and cancer cachexia are reviewed, with an emphasis placed on prospective studies.

Oral care reduces incidence of pneumonia after esophagectomy: systematic review and meta-analysis.

PURPOSE: Post-operative pneumonia after esophagectomy is a major contributor to morbidity and mortality. Prior studies have demonstrated a link between the presence of pathologic oral flora and the development of aspiration pneumonia. The objective of this systematic review and meta-analysis was to evaluate the effect of pre-operative oral care on the incidence of post-operative pneumonia after esophagectomy. METHODS: A systematic search of the literature was performed on September 2, 2022. Screening of titles and abstracts, full-text articles, and evaluation of methodological quality was performed by two authors. Case reports, conference proceedings, and animal studies were excluded. A meta-analysis of peri-operative oral care on the odds of post-operative pneumonia after esophagectomy was performed using Revman 5.4.1 with a Mantel-Haenszel, random-effects model. RESULTS: A total of 736 records underwent title and abstract screening, leading to 28 full-text studies evaluated for eligibility. A total of nine studies met the inclusion criteria and underwent meta-analysis. Meta-analysis revealed a significant reduction in post-operative pneumonia among patients undergoing pre-operative oral care intervention compared to those without an oral care intervention (OR 0.57, 95% CI 0.43-0.74, p < 0.0001; I2 = 49%). CONCLUSION: Pre-operative oral care interventions have significant potential in the reduction of post-operative pneumonia after esophagectomy. North American prospective studies, as well as studies on the cost-benefit analysis, are required.

Sex and racial diversity in Canadian academic surgery.

To ensure equitable representation of women and BIPOC (Black, Indigenous, person of colour) individuals in surgical specialties, it is first necessary to understand the presence and extent of the disparities that exist. We explored the websites of the 17 Canadian faculties of medicine to examine sex and racial diversity in surgical specialties and in surgical leadership positions in Canada. We categorized faculty members of each department of surgery as either male or female and White or BIPOC. The relative percentage of female academic surgeons was very low compared with Canadian demographic data, and the relative percentage of BIPOC academic surgeons was similar to Canadian demographic data. Our observations suggest that actions must be taken to improve diversity and inclusion in surgery.

Learning objectives for thoracic surgery: developing a national standard for undergraduate medical education.

BACKGROUND: The Continuing Professional Development (CPD) (Education) Committee of the Canadian Association of Thoracic Surgeons (CATS) has established a goal of describing the essential knowledge of thoracic surgery. We aimed to develop a national standardized set of undergraduate learning objectives for thoracic surgery. METHODS: We obtained these learning objectives from 4 medical schools in Canada. These 4 institutions were selected to provide a broad geographical representation of medical schools of varying sizes and of both official languages. The resulting list of learning objectives underwent critical review by the CPD (Education) Committee, made up of 5 Canadian community and academic thoracic surgeons, 1 thoracic surgery fellow and 2 general surgery residents. A national survey was developed and circulated to all CATS members (n = 209). Respondents were asked to indicate on a 5-point Likert scale whether each objective should be a priority for all medical students. RESULTS: Among 209 CATS members, 56 responded (response rate 27%). The mean length of experience in clinical practice among survey respondents was 10.6 (standard deviation 10.0) years. Respondents most commonly reported teaching or supervising medical students monthly (37.0%), followed by daily (29.6%). Eight of the 10 proposed objectives received a mean Likert score of 4/5 or higher and were selected for inclusion in the final list. A finalized list of 8 learning objectives was created, following a final review from the CATS Executive Committee. CONCLUSION: We developed a standardized set of learning objectives for medical students that was reflective of the core concepts within thoracic surgery.

Presurgical radiation and chemotherapy in preparation for thoracic tumor resection.

PURPOSE OF REVIEW: This article aims at describing the role of neoadjuvant chemotherapy, radiation therapy as well the novel immunotherapy and targeted therapy in thoracic oncology with focus on anesthetic considerations of such treatments for the surgical patient. RECENT FINDINGS: In recent years, immune check point inhibitors have changed the landscape of thoracic oncology treatment. In this review, we summarize the key studies that have been fundamental in this change. SUMMARY: Rather than a comprehensive review, the purpose of this work is to provide the reader with an overview of the most common neoadjuvant regimens used in current practice, with the corresponding most prevalent adverse effects as it pertains for patients with esophageal and lung cancer, malignant pleural mesothelioma and mediastinal tumors. Considerations relevant to the anesthesiologist, including specific toxicities related to each treatment type, and the impact of each treatment type on perioperative outcomes and complications will be discussed.

Validity Evidence for Procedure-specific Competence Assessment Tools in General Surgery: A Scoping Review.

OBJECTIVE: This study aims to provide a focused and detailed assessment of the validity evidence supporting procedure-specific operative assessment tools in general surgery. SUMMARY OF BACKGROUND DATA: Competency-based assessment tools should be supported by robust validity evidence to be used reliably for evaluation of operative skills. The contemporary framework of validity relies on five sources of evidence: content, response process, internal structure, relation to other variables, and consequences. METHODS: A systematic search of 8 databases was conducted for studies containing procedure-specific operative assessment tools in general surgery. The validity evidence supporting each tool was assessed and scored in alignment with the contemporary framework of validity. Methodological rigour of studies was assessed with the Medical Education Research Study Quality Instrument. The educational utility of each tool was assessed with the Accreditation Council for Graduate Medical Education framework. RESULTS: There were 28 studies meeting inclusion criteria and 23 unique tools were assessed. Scores for validity evidence varied widely between tools, ranging from 3 - 14 (maximum 15). Medical Education Research Study Quality Instrument scores assessing the quality of study methodology were also variable (8.5-15.5, maximum 16.5). Direct reporting of educational utility criteria was limited. CONCLUSIONS: This study has identified a small group of procedure-specific operative assessment tools in general surgery. Many of these tools have limited validity evidence and have not been studied sufficiently to be used reliably in high-stakes summative assessments. As general surgery transitions to competency-based training, a more robust library of operative assessment tools will be required to support resident education and evaluation.

Sarcopenia Determined by Skeletal Muscle Index Predicts Overall Survival, Disease-free Survival, and Postoperative Complications in Resectable Esophageal Cancer: A Systematic Review and Meta-analysis.

BACKGROUND: Sarcopenia has been identified as a prognostic factor among certain types of cancer. In esophageal cancer, patients are at increased risk of malnutrition and sarcopenia, ultimately contributing to poor outcomes. A systematic review was conducted to determine whether sarcopenia, defined by the skeletal muscle index, is predictive of overall survival, disease-free survival, and postoperative complications in resectable esophageal cancer. MATERIALS AND METHODS: A systematic search of MEDLINE, EMBASE, Scopus, Web of Science, and Cochrane Library was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines up until January 2021. The primary outcome was overall survival; secondary outcomes included disease-free survival, pulmonary complications, and anastomotic leak. RESULTS: Twenty-one studies (4 prospective; 17 retrospective; 3966 patients) were included. Sarcopenia was present in 1940 (48.1%) patients and was associated with lower overall survival [hazard ratio (HR): 1.56; 95% confidence interval (CI): 1.25-1.95; P <0.00001; I2 =71%] and disease-free survival (HR: 1.73; 95% CI: 1.04-2.87; P =0.03; I2 =51%). A decrease in skeletal muscle index, independent of sarcopenia status, was associated with lower overall survival (HR: 1.81; 95% CI: 1.20-2.73; P =0.005; I2 =92%). Sarcopenia was associated with increased odds of pulmonary complications (odds ratio: 1.86; 95% CI: 1.29-2.66; P =0.0008; I2 =41%) and increased odds of anastomotic leak (odds ratio: 1.46; 95% CI: 1.11-1.93; P =0.008; I2 =0%). CONCLUSIONS: Sarcopenia is a predictor of overall survival, disease-free survival, and postoperative complications in patients with resectable esophageal cancer. Studies on the modifiability of sarcopenia in the preoperative period will help determine the utility of nutritional interventions.

Organ-specific genetic interactions between paralogues of the PXY and ER receptor kinases enforce radial patterning in Arabidopsis vascular tissue.

In plants, cells do not migrate. Tissues are frequently arranged in concentric rings; thus, expansion of inner layers is coordinated with cell division and/or expansion of cells in outer layers. In Arabidopsis stems, receptor kinases, PXY and ER, genetically interact to coordinate vascular proliferation and organisation via inter-tissue signalling. The contribution of PXY and ER paralogues to stem patterning is not known, nor is their function understood in hypocotyls, which undergo considerable radial expansion. Here, we show that removal of all PXY and ER gene-family members results in profound cell division and organisation defects. In hypocotyls, these plants failed to transition to true radial growth. Gene expression analysis suggested that PXY and ER cross- and inter-family transcriptional regulation occurs, but it differs between stem and hypocotyl. Thus, PXY and ER signalling interact to coordinate development in a distinct manner in different organs. We anticipate that such specialised local regulatory relationships, where tissue growth is controlled via signals moving across tissue layers, may coordinate tissue layer expansion throughout the plant body.

Stigma in Early-Stage Lung Cancer.

BACKGROUND: The phenomenon of lung cancer stigma has been firmly established in the literature. However, studies have predominantly focused on patients with advanced disease, whose experiences may differ from patients with earlier stage, surgically resectable lung cancer and an improved prognosis. PURPOSE: The objective of the study was to examine the stigma experienced in a Canadian population with early-stage, resectable lung cancer. METHODS: Patients with newly diagnosed lung cancer were enrolled at a tertiary thoracic surgery clinic. The 25-item Lung Cancer Stigma Inventory (LCSI) was self-administered by patients to quantitatively measure experiences of lung cancer stigma. LCSI results informed the development of a semi-structured focus group and individual interviews. RESULTS: Of the 53 participants completing the survey, 38 (72%) met established LCSI score threshold, indicating a clinically meaningful level of stigma. No significant relationship was found between total LCSI scores and any demographic variable. Analysis of qualitative data revealed multiple themes related to experiences of lung cancer stigma. The major themes were classified into four categories: impact of the association between lung cancer and smoking, societal attitudes and assumptions, personal choices in relation to diagnosis, and experiences related to care. CONCLUSIONS: A surgical population of patients with predominantly early-stage lung cancer experienced lung cancer stigma at a high incidence and a level similar to previously studied populations with more advanced disease. The qualitative results support the quantitative findings that respondents experienced more internal stigma than either perceived stigma from others or constrained disclosure related to their diagnosis.

Gastric ischemic conditioning prior to esophagectomy reduces anastomotic leaks and strictures: a systematic review and meta-analysis.

BACKGROUND: Gastric ischemic conditioning (GIC) is a strategy to promote neovascularization of the gastric conduit to reduce the risk of anastomotic complications following esophagectomy. Despite a number of studies and reviews published on the concept of ischemic conditioning, there remains no clear consensus regarding its utility. We performed an updated systematic review and meta-analysis to determine the impact of GIC, particularly on anastomotic leaks, conduit ischemia, and strictures. METHODS: A systematic search of MEDLINE, EMBASE, Scopus, Web of Science, and Cochrane Library was performed on February 5th, 2020 by a university librarian after selection of key search terms with the research team. Inclusion criteria included human participants undergoing esophagectomy with gastric conduit reconstruction, age ≥ 18, N ≥ 5, and GIC performed prior to esophagectomy. Our primary outcome of interest was anastomotic leaks. Our secondary outcome was gastric conduit ischemia, anastomotic strictures, and overall survival. Meta-analysis was performed with RevMan 5.4.1 using a Mantel-Haenszel fixed-effects model. RESULTS: A total of 1712 preliminary studies were identified and 23 studies included for final review. GIC was performed in 1178 (53.5%) patients. Meta-analysis revealed reduced odds of anastomotic leaks (OR 0.67; 95% CI 0.46-0.97; I2 = 5%; p = 0.03) and anastomotic strictures (OR 0.48; 95% CI 0.29-0.80; I2 = 65%; p = 0.005). Meta-analysis revealed no difference in odds of conduit ischemia (OR 0.40; 95% CI 0.13-1.23; I2 = 0%; p = 0.11) and no difference in odds of overall survival (OR 0.54; 95% CI 0.29-1.02; I2 = 22%; p = 0.06). CONCLUSION: GIC is associated with reduced odds of anastomotic leaks and anastomotic strictures and may decrease morbidity in patients undergoing esophagectomy. Further prospective randomized trials are needed to better identify the optimal patient population, timing, and techniques used to best achieve GIC.

Yield of routine staging laparoscopy in patients with gastric cancer in Alberta, Canada.

BACKGROUND: Despite guidelines recommending diagnostic laparoscopy in patients with gastric cancer, implementation is low. We aimed to explore trends in the use of laparoscopy for staging of gastric cancer in Alberta, Canada, determine the rate of positive findings and identify factors predictive of positive staging laparoscopy (SL) findings in this patient population. METHODS: In August 2018, we sent a survey to all general surgeons in Alberta who were members of the Alberta Association of General Surgeons to identify those treating gastric cancer. The survey inquired about type of practice (academic or community), gastric cancer case volume, routine versus selective use of SL and, if selective use of SL, criteria used to select cases. Participants were also asked to provide data from their SL cases from July 2007 to February 2019. We double-checked surgeon records with chart review. The primary outcome was evidence of metastatic disease on SL or cytologic examination or both. We performed logistic regression analysis to identify factors predictive of positive laparoscopy findings. RESULTS: The survey was completed by 41 of 127 surgeons (response rate 32.3%). We reviewed 116 cases from 5 surgeons at 4 centres. Gross metastatic disease or positive findings on cytologic examination or both were identified in 37 patients (31.9%). On univariate analysis, the following were associated with an increased risk of identification of metastatic disease at laparoscopy: visualization of the primary tumour on computed tomography (CT) (odds ratio [OR] 9.8, 95% confidence interval [CI] 1.2-76.5), presence of abdominal lymphadenopathy greater than 1 cm (OR 2.4, 95% CI 1.1-5.4) and presence of ascites (OR 19.1, 95% CI 2.2-161.8). Visualization of the primary tumour on CT (OR 8.4, 95% CI 1.0-68.3) and the presence of ascites (OR 15.9, 95% CI 1.8-137.0) remained statistically significant predictors on multivariate analysis. CONCLUSION: Metastatic disease was identified at SL in almost one-third of cases, which suggests that SL should still be used routinely in gastric cancer staging in Canadian centres. Our study identified several preoperative imaging findings associated with evidence of metastatic disease on laparoscopy; however, further studies are needed to establish robust predictors of positive findings before advocating for a selective SL approach.

An essential role for abscisic acid in the regulation of xylem fibre differentiation.

Division of the cambial cells and their subsequent differentiation into xylem and phloem drives radial expansion of the hypocotyl. Following the transition to reproductive growth, a phase change occurs in the Arabidopsis hypocotyl. During this second phase, the relative rate of xylem production is dramatically increased compared with that of phloem, and xylem fibres that contain thick secondary cell walls also form. Using two different genetic backgrounds and different environmental conditions, we identified a set of core transcriptional changes that is associated with the switch to the second phase of growth in the hypocotyl. Abscisic acid (ABA) signalling pathways are significantly over-represented in this set of core genes. Reverse genetic analysis demonstrated that mutants that are defective in ABA-biosynthesis enzymes exhibited significantly delayed fibre production without affecting the xylem:phloem ratio, and that these effects can be reversed by the application of ABA. The altered morphology is also reflected at the transcript level, with a reduced expression of marker genes that are associated with fibre formation in aba1 mutants. Taken together, the data reveal an essential role for ABA in the regulation of fibre formation.

The molecular basis of plant cellulose synthase complex organisation and assembly.

The material properties of cellulose are heavily influenced by the organisation of ß-1,4-glucan chains into a microfibril. It is likely that the structure of this microfibril is determined by the spatial arrangement of catalytic cellulose synthase (CESA) proteins within the cellulose synthase complex (CSC). In land plants, CESA proteins form a large complex composed of a hexamer of trimeric lobes termed the rosette. Each rosette synthesises a single microfibril likely composed of 18 glucan chains. In this review, the biochemical events leading to plant CESA protein assembly into the rosette are explored. The protein interfaces responsible for CESA trimerization are formed by regions that define rosette-forming CESA proteins. As a consequence, these regions are absent from the ancestral bacterial cellulose synthases (BcsAs) that do not form rosettes. CSC assembly occurs within the context of the endomembrane system, however the site of CESA assembly into trimers and rosettes is not determined. Both the N-Terminal Domain and Class Specific Region of CESA proteins are intrinsically disordered and contain all of the identified phosphorylation sites, making both regions candidates as sites for protein-protein interactions and inter-lobe interface formation. We propose a sequential assembly model, whereby CESA proteins form stable trimers shortly after native folding, followed by sequential recruitment of lobes into a rosette, possibly assisted by Golgi-localised STELLO proteins. A comprehensive understanding of CESA assembly into the CSC will enable directed engineering of CESA protein spatial arrangements, allowing changes in cellulose crystal packing that alter its material properties.