Colectomy and desmoid tumours in familial adenomatous polyposis: a systematic review and meta-analysis

Desmoid tumours (DT) are one of the main causes of death in patients with familial adenomatous polyposis (FAP). Surgical trauma is a risk factor for DT, yet a colectomy is inevitable in FAP to prevent colorectal cancer. This systematic review and meta-analysis aimed to synthesize the available evidence on DT risk related to type, approach and timing of colectomy. A search was performed in MEDLINE, EMBASE and the Cochrane Library. Studies were considered eligible when DT incidence was reported after different types, approaches and timing of colectomy. Twenty studies including 6452 FAP patients were selected, all observational. No significant difference in DT incidence was observed after IRA versus IPAA (OR 0.99, 95% CI 0.69–1.42) and after open versus laparoscopic colectomy (OR 0.88, 95% CI 0.42–1.86). Conflicting DT incidences were seen after early versus late colectomy and when analysing open versus laparoscopic colectomy according to colectomy type. Three studies reported a (non-significantly) higher DT incidence after laparoscopic IPAA compared to laparoscopic IRA, with OR varying between 1.77 and 4.09. A significantly higher DT incidence was observed in patients with a history of abdominal surgery (OR 3.40, 95% CI 1.64–7.03, p = 0.001). Current literature does not allow to state firmly whether type, approach, or timing of colectomy affects DT risk in FAP patients. Fewer DT were observed after laparoscopic IRA compared to laparoscopic IPAA, suggesting laparoscopic IRA as the preferred choice if appropriate considering rectal polyp burden. PROSPERO registration number CRD42020161424.

Time Between Viral Loads for People with HIV during the COVID-19 Pandemic

Background: During the COVID-19 pandemic, patients experienced significant care disruptions, including lab monitoring. We investigated changes in the time between viral load (VL) checks for people with HIV associated with the pandemic. Methods: This was an observational analysis of VLs of people with HIV in routine care at a large subspecialty clinic. At pandemic onset, the clinic temporarily closed its onsite laboratory. The exposure was time period (time-varying): pre-pandemic (January 1st 2019-March 15th, 2020); pandemic lab-closed (March 16th-July 12th, 2020); and pandemic lab-open (July 13th-December 31st, 2020). We estimated time from an index VL to a subsequent VL, stratified by whether the index VL was suppressed (≤200 copies/mL). We also calculated cumulative incidence of a non-suppressed VL following a suppressed index VL, and of re-suppression following a loss of viral suppression. Results: Compared to pre-pandemic, hazard ratios for next VL check were: 0.34 (95% CI: 0.30, 0.37, lab-closed) and 0.73 (CI: 0.68, 0.78, lab-open) for suppressed patients; 0.56 (CI: 0.42, 0.79, lab-closed) and 0.92 (95% CI: 0.76, 1.10, lab-open) for non-suppressed patients. The 12-month cumulative incidence of loss of suppression was the same in the pandemic lab-open (4%) and pre-pandemic period (4%). The hazard of re-suppression following loss of suppression was lower during the pandemic lab-open versus the pre-pandemic period (hazard ratio: 0.68, 95% CI: 0.50, 0.92). Conclusions: Early pandemic restrictions and lab closure significantly delayed VL monitoring. Once the lab re-opened, non-suppressed patients resumed normal monitoring. Suppressed patients still had a delay, but no significant loss of suppression.

Multi-omics reveal differentiation and maintenance of dimorphic flowers in an alpine plant on the Qinghai-Tibet Plateau

 Dimorphic flowers growing on a single individual plant play a critical role in extreme adaption and reproductive assurance in plants and have high ecological and evolutionary significance. However, the omics bases underlying such a differentiation and maintenance remain largely unknown. We aimed to investigate this through genomic, transcriptome and metabolomic analyses of dimorphic flowers in an alpine biennial, Sinoswertia tetraptera (Gentianaceae).  A high-quality chromosome-level genome sequence (903 Mb) was first assembled for S. tetraptera with 31,359 protein-coding genes annotated. Two rounds of recent independent whole-genome duplication (WGD) were revealed. More than 10% of the novel genes from the recent species-specific WGD were found to be differentially expressed in the two types of flowers, and this may have helped contribute to the origin of this innovative trait.  Other contrasting gene expression between flowers included that related to flower development and color, hormones, and iridoid biosynthesis. Metabolomic analyses similarly suggested differential concentrations of both hormones and iridoids in the two types of flowers. The interactions between multiple genes may together lead to contrasting morphology and open versus closed pollination of the dimorphic flowers in this species.  A total of 56 candidate genes were identified from the known iridoid biosynthesis-related pathways. Two hub genes were found to play an essential role in transferring intermediate products between leaves and flowers during iridoid biosynthesis.

P-BN51 Subtotal cholecystectomy: risk factors and patient outcomes

Background A subtotal cholecystectomy (SC) is indicated when a total cholecystectomy (TC) cannot be achieved without the risk of causing significant harm, the most feared complication being a bile duct injury. The aims of the present study were to identify patients at risk of SC, to compare the peri- and post-operative course between SC and TC and to compare outcomes between fenestrated and reconstituting subtypes. Methods All planned laparoscopic cholecystectomies across three surgical units over a population of 493,000 between 2015 and 2019 were considered. Data were collected retrospectively using electronic databases and included pre-operative, operative and post-operative data over a 100-day follow-up period. Variables associated with SC were identified using multivariate logistic regression. Outcomes following SC were compared with TC using univariate analysis, specifically chi-squared and Mann-Whitney U tests. The subtype of SC was documented and outcomes were compared between groups. Results The rate of SC was 3.4% (94/2768). Variables positively associated with SC included male sex (OR-2.33;p<0.001), age≥60 (OR-1.79;p=0.009), 2 previous admissions (OR-1.76;p=0.043), ≥3 previous admissions (OR-3.10;p=0.003), emergency cholecystectomy (OR-2.01;p=0.002); cholecystitis (OR-4.92;p<0.001) and pre-operative ERCP (OR-2.23;p<0.002). Patients with SC versus TC were more likely to suffer intra-operative complications (RR-13.1;p<0.001), post-operative complication (RR-6.7;p<0.001), require post-operative imaging/intervention (RR-4.0;p<0.001) and be re-admitted (RR-4.2; p < 0.001). The rate of bile duct injury was 0% in SC patients. The rate of post-operative bile leak was higher where the cystic duct was left open versus closed (RR-2.9;p=0.03) and in fenestrating SC versus reconstituting SC (35.7% versus 0%;p=0.002). Drain duration was reduced in reconstituting SC (p < 0.001). Conclusions The risk of SC can be explained by a number of patient specific factors and the risk should be emphasized in these patients during the consent process and should influence surgical decision making. The morbidity following a subtotal cholecystectomy is markedly higher than that of a total cholecystectomy but can be performed without significant risk of bile duct injury. Reconstituting SC and closure of the cystic duct reduces rates of post-operative bile leaks and duration of drains.