Postoperative outcomes and identification of risk factors for complications after emergency intestinal stoma surgery - a multicentre retrospective study.

AIM: Approximately 4000 patients in the UK have an emergency intestinal stoma formed each year. Stoma-related complications (SRCs) are heterogeneous but have previously been subcategorized into early or late SRCs, with early SRCs generally occurring within 30 days postoperatively. Early SRCs include skin excoriation, stoma necrosis and high output, while late SRCs include parastomal hernia, retraction and prolapse. There is a paucity of research on specific risk factors within the emergency cohort for development of SRCs. This paper aims to describe the incidence of SRCs after emergency intestinal surgery and to identify potential risk factors for SRCs within this cohort. METHOD: Consecutive patients undergoing emergency formation of an intestinal stoma (colostomy, ileostomy or jejunostomy) were identified prospectively from across three acute hospital sites over a 3-year period from the ELLSA (Emergency Laparotomy and Laparoscopic Scottish Audit) database. All patients were followed up for a minimum of 1 year. A multivariate logistic regression model was used to identify risk factors for early and late SRCs. RESULTS: A total of 455 patients were included (median follow-up 19 months, median age 64 years, male:female 0.52, 56.7% ileostomies). Early SRCs were experienced by 54.1% of patients, while 51% experienced late SRCs. A total of 219 patients (48.1%) had their stoma sited preoperatively. Risk factors for early SRCs included end ileostomy formation [OR 3.51 (2.24-5.49), p < 0.001], while preoperative stoma siting was found to be protective [OR 0.53 (0.35-0.83), p = 0.005]. Patient obesity [OR 3.11 (1.92-5.03), p < 0.001] and reoperation for complications following elective surgery [OR 4.18 (2.01-8.69), p < 0.001] were risk factors for late SRCs. CONCLUSION: Stoma-related complications after emergency surgery are common. Preoperative stoma siting is the only truly modifiable risk factor to reduce SRCs, and further research should be aimed at methods of improving the frequency and accuracy of this in the emergency setting.

Outcomes of Fluorescence-Guided vs White Light Resection of Glioblastoma in a Single Institution.

Background Glioblastoma (GBM) is the most common malignant primary brain tumour and confers a very poor prognosis. Maximal safe resection of tumour is the goal of neurosurgical intervention and may be more easily achieved through the use of surgical adjuncts such as fluorescence-guided surgery (FGS). 5-Aminolevulinic acid (5-ALA) accumulates in GBM tissue and fluoresce red, distinguishing tumour cells from the surrounding tissue and therefore making resection easier. 5-ALA-guided resection in GBM has been shown to increase resection rates and prolong progression-free survival without impacting post-operative morbidity. Radiotherapy and concomitant chemotherapy also improve survival in GBM. Other factors such as patient age and molecular status of the tumour also impact prognosis. Aims The aim of this study was to compare the outcomes of 5-ALA vs white light-guided resection for glioblastoma in the west of Scotland. Methods  This was a retrospective analysis of baseline characteristics (age, sex, tumour molecular markers, radiotherapy, chemotherapy, anatomical location of tumour and treatment group) and outcomes (mortality, survival, degree of resection and performance status) of 239 patients who underwent primary resection of glioblastoma over a four-year period (2017-2020). A variety of statistical methods were used to analyse the relationship between each variable and surgical technique; multivariate Cox regression and the Kaplan-Meier method were used in survival analysis. Results  5-ALA-guided resection substantially improved resection rates (74.0% vs 40.2%). Mortality at 15 months was 5.1% lower in the 5-ALA group (52.0% vs 57.1%, p = 0.53), and patients lived an average of 68 days longer compared to the white light group (444 days vs 376 days, p = 0.21). There were negligible differences between treatment groups in terms of post-operative performance status (PS) and post-operative complications. In our multivariate Cox regression model, six factors were statistically significant at a level of p ≤ 0.05: age, radiotherapy, chemotherapy, O(6)-methylguanine-DNA methyltransferase (MGMT) methylation, anatomical location and >90% resection. Receiving chemotherapy and radiotherapy, MGMT methylation and undergoing >90% resection conferred a survival benefit at 15 months. Older age and multi-focal disease were related to a worsened mortality rate. Undergoing radiotherapy and maximal resection were the two greatest predictors of improved survival, reducing mortality risk by 58% and 51%, respectively. Conclusion 5-ALA-guided resection improved resection rates without impacting post-operative morbidity. 5-ALA-guided resection was associated with improved survival and lower mortality rate, but this was not statistically significant. Receiving chemoradiotherapy, MGMT methylation and undergoing maximal resection conferred a survival benefit, whilst older age and multi-focal disease were associated with a poorer prognosis.

The impact of intestinal stoma formation on patient quality of life after emergency surgery-A systematic review.

AIM: Elective stoma formation has a negative effect on patient quality of life (QoL), with a potential detrimental impact on body image, confidence and social functioning being shown previously. However, the impact of emergency stoma formation on QoL has been explored less frequently. This systematic review aims to synthesize all available literature exploring QoL via patient-reported outcome measures. METHODS: A search strategy was implemented on 24 November 2022 across Embase, MEDLINE, PsycInfo and the Cochrane Library database after registration on PROSPERO (CRD42022370606). Studies were included if they used a standardized patient-reported outcome measure, had more than five emergency stoma patients, age > 18 years and were fully published in English. Two of three independent researchers screened articles, extracted data and performed quality assessment using the Newcastle-Ottawa Scale and the Cochrane risk of bias tool. RESULTS: In all, 1775 articles were screened, with 16 included in the systematic review. This included 1868 emergency stoma patients (men:women 0.53; median age 64.6 years) followed up for a median of 12 months. Patients who had a Hartmann's procedure for perforated diverticulitis had poorer QoL than those who underwent primary anastomosis. There was a negligible difference in QoL between those who had a colonic stent for obstructing colorectal cancer compared with those who underwent emergency stoma formation. Female sex, end stoma formation and ileostomy formation were all identified as risk factors for poorer QoL. CONCLUSION: Patients undergoing emergency stoma surgery have marginally poorer QoL compared with those undergoing similar procedures without stoma formation. Further work is required to identify risk factors associated with this and also to compare QoL after stoma reversal.

Superior Fidelity and Distinct Editing Outcomes of SaCas9 Compared to SpCas9 in Genome Editing.

A series of the clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR associated protein 9 (Cas9) systems have been engineered for genome editing. The most widely used Cas9 is SpCas9 from Streptococcus pyogenes and SaCas9 from Staphylococcus aureus. However, a comparison of their detailed gene editing outcomes is still lacking. By characterizing the editing outcomes of 11 sites in human induced pluripotent stem cells (iPSCs) and K562 cells, we found that SaCas9 could edit the genome with greater efficiency than SpCas9. We also compared the spacer lengths of single-guide RNA (sgRNA, 18-21 nt for SpCas9 and 19-23 nt for SaCas9) and found that the optimal spacer lengths were 20 nt and 21 nt for SpCas9 and SaCas9, respectively. However, the optimal spacer size for a particular guide RNA ranged from 18-21 nt or 21-22 nt for SpCas9 and SaCas9, respectively. Furthermore, SpCas9 exhibited a more substantial bias than SaCas9 for nonhomologous end-joining (NHEJ) +1 insertion at the fourth nucleotide upstream of the protospacer adjacent motif (PAM), characteristic of a staggered cut. Accordingly, editing with SaCas9 led to higher knock-in efficiencies of NHEJ-mediated double-stranded oligodeoxynucleotide (dsODN) insertion or adeno-associated virus serotype 6 (AAV6) donor-mediated homology-directed repair (HDR). Finally, GUIDE-seq analysis revealed that SaCas9 exhibited significantly reduced off-target effects compared with SpCas9. Our work indicates the superior performance of SaCas9 to SpCas9 in transgene integration-based therapeutic gene editing and the necessity to identify the optimal spacer length to achieve desired editing results.

Effective control of large deletions after double-strand breaks by homology-directed repair and dsODN insertion.

BACKGROUND: After repairing double-strand breaks (DSBs) caused by CRISPR-Cas9 cleavage, genomic damage, such as large deletions, may have pathogenic consequences. RESULTS: We show that large deletions are ubiquitous but are dependent on editing sites and cell types. Human primary T cells display more significant deletions than hematopoietic stem and progenitor cells (HSPCs), whereas we observe low levels in induced pluripotent stem cells (iPSCs). We find that the homology-directed repair (HDR) with single-stranded oligodeoxynucleotides (ssODNs) carrying short homology reduces the deletion damage by almost half, while adeno-associated virus (AAV) donors with long homology reduce large deletions by approximately 80%. In the absence of HDR, the insertion of a short double-stranded ODN by NHEJ reduces deletion indexes by about 60%. CONCLUSIONS: Timely bridging of broken ends by HDR and NHEJ vastly decreases the unintended consequences of dsDNA cleavage. These strategies can be harnessed in gene editing applications to attenuate unintended outcomes.

Metabolic Mechanisms and a Rational Combinational Application of Carboxyamidotriazole in Fighting Pancreatic Cancer Progression after Chemotherapy.

The anticancer and anti-inflammatory effects of carboxyamidotriazole (CAI) have been demonstrated in several studies, but the underlying mechanisms remain to be elucidated. This study showed that CAI caused metabolic reprogramming of pancreatic cancer cells. The inhibition of mitochondrial oxidative metabolism by CAI led to increased glutamine-dependent reductive carboxylation and enhanced glycolytic metabolism. The presence of environmental substances that affect cellular metabolism, such as glutamine and pyruvate, attenuated the anticancer efficacy of CAI. Based on the action of CAI: 1) when glutamine was removed, the NAD+/NADH ratio was decreased, the synthesis of cellular aspartate was reduced, and autophagy flux was blocked; and 2) when glycolysis was pharmacologically inhibited, the ATP level was significantly decreased, the cell viability was greatly inhibited, and the compensatory rescue effect of glutamine was eliminated. When combined with chemotherapy, cotreatment with CAI and the glycolysis inhibitor 2-deoxyglucose (2-DG) inhibited the pancreatic cancer progression after chemotherapy. As the inhibition of mitochondrial oxidative metabolism can explain several anticancer activities of CAI reported previously, including inhibition of calcium entry and induction of reactive oxygen species, we demonstrate that inhibition of mitochondrial oxidative phosphorylation may be the fundamental mechanism of CAI. The combination of CAI and 2-DG causes energy depletion in cancer cells, eliminating the rescue effect of the metabolic environment. Inhibiting pancreatic cancer progression after chemotherapy is a rational application of this metabolism-disturbing combination strategy.

A rapid process for fabricating gas sensors.

Zinc oxide (ZnO) is a low-toxicity and environmentally-friendly material applied on devices, sensors or actuators for "green" usage. A porous ZnO film deposited by a rapid process of aerosol deposition (AD) was employed as the gas-sensitive material in a CO gas sensor to reduce both manufacturing cost and time, and to further extend the AD application for a large-scale production. The relative resistance change (△R/R) of the ZnO gas sensor was used for gas measurement. The fabricated ZnO gas sensors were measured with operating temperatures ranging from 110 °C to 180 °C, and CO concentrations ranging from 100 ppm to 1000 ppm. The sensitivity and the response time presented good performance at increasing operating temperatures and CO concentrations. AD was successfully for applied for making ZnO gas sensors with great potential for achieving high deposition rates at low deposition temperatures, large-scale production and low cost.