PD-1 and PD-L1 inhibitors in cold colorectal cancer: challenges and strategies.

Colorectal cancer (CRC) is the second most common cause of cancer mortality, with mismatch repair proficient (pMMR) and/or microsatellite stable (MSS) CRC making up more than 80% of metastatic CRC. Programmed death-ligand 1 (PD-L1) and programmed death 1 (PD-1) immune checkpoint inhibitors (ICIs) are approved as monotherapy in many cancers including a subset of advanced or metastatic colorectal cancer (CRC) with deficiency in mismatch repair (dMMR) and/or high microsatellite instability (MSI-H). However, proficient mismatch repair and microsatellite stable (pMMR/MSS) cold CRCs have not shown clinical response to ICIs alone. To potentiate the anti-tumor response of PD-L1/PD-1 inhibitors in patients with MSS cold cancer, combination strategies currently being investigated include dual ICI, and PD-L1/PD-1 inhibitors in combination with chemotherapy, radiotherapy, vascular endothelial growth factor (VEGF) /VEGF receptor (VEGFR) inhibitors, mitogen-activated protein kinase (MEK) inhibitors, and signal transducer and activation of transcription 3 (STAT3) inhibitors. This paper will review the mechanisms of PD-1/PD-L1 ICI resistance in pMMR/MSS CRC and potential combination strategies to overcome this resistance, summarize the published clinical experience with different combination therapies, and make recommendations for future avenues of research.

Closing the gap on healthcare quality for equity-deserving groups: a scoping review of equity-focused quality improvement interventions in medicine.

INTRODUCTION: Quality improvement (QI) efforts are critical to promoting health equity and mitigating disparities in healthcare outcomes. Equity-focused QI (EF-QI) interventions address the unique needs of equity-deserving groups and the root causes of disparities. This scoping review aims to identify themes from EF-QI interventions that improve the health of equity-deserving groups, to serve as a resource for researchers embarking on QI. METHODS: In adherence with Preferred Reporting Items for Systematic Reviews and Meta-analysis guidelines, several healthcare and medical databases were systematically searched from inception to December 2022. Primary studies that report results from EF-QI interventions in healthcare were included. Reviewers conducted screening and data extraction using Covidence. Inductive thematic analysis using NVivo identified key barriers to inform future EF-QI interventions. RESULTS: Of 5,330 titles and abstracts screened, 36 articles were eligible for inclusion. They reported on EF-QI interventions across eight medical disciplines: primary care, obstetrics, psychiatry, paediatrics, oncology, cardiology, neurology and respirology. The most common focus was racialised communities (15/36; 42%). Barriers to EF-QI interventions included those at the provider level (training and supervision, time constraints) and institution level (funding and partnerships, infrastructure). The last theme critical to EF-QI interventions is sustainability. Only six (17%) interventions actively involved patient partners. DISCUSSION: EF-QI interventions can be an effective tool for promoting health equity, but face numerous barriers to success. It is unclear whether the demonstrated barriers are intrinsic to the equity focus of the projects or can be generalised to all QI work. Researchers embarking on EF-QI work should engage patients, in addition to hospital and clinic leadership in the design process to secure funding and institutional support, improving sustainability. To the best of our knowledge, no review has synthesised the results of EF-QI interventions in healthcare. Further studies of EF-QI champions are required to better understand the barriers and how to overcome them.

Reperfusion after hypoxia-ischemia exacerbates brain injury with compensatory activation of the anti- ferroptosis system: based on a novel rat model.

Hypoxic-ischemic encephalopathy, which predisposes to neonatal death and neurological sequelae, has a high morbidity, but there is still a lack of effective prevention and treatment in clinical practice. To better understand the pathophysiological mechanism underlying hypoxic-ischemic encephalopathy, in this study we compared hypoxic-ischemic reperfusion brain injury and simple hypoxic-ischemic brain injury in neonatal rats. First, based on the conventional Rice-Vannucci model of hypoxic-ischemic encephalopathy, we established a rat model of hypoxic-ischemic reperfusion brain injury by creating a common carotid artery muscle bridge. Then we performed tandem mass tag-based proteomic analysis to identify differentially expressed proteins between the hypoxic-ischemic reperfusion brain injury model and the conventional Rice-Vannucci model and found that the majority were mitochondrial proteins. We also performed transmission electron microscopy and found typical characteristics of ferroptosis, including mitochondrial shrinkage, ruptured mitochondrial membranes, and reduced or absent mitochondrial cristae. Further, both rat models showed high levels of glial fibrillary acidic protein and low levels of myelin basic protein, which are biological indicators of hypoxic-ischemic brain injury and indicate similar degrees of damage. Finally, we found that ferroptosis-related Ferritin (Fth1) and glutathione peroxidase 4 were expressed at higher levels in the brain tissue of rats with hypoxic-ischemic reperfusion brain injury than in rats with simple hypoxic-ischemic brain injury. Based on these results, it appears that the rat model of hypoxic-ischemic reperfusion brain injury is more closely related to the pathophysiology of clinical reperfusion. Reperfusion not only aggravates hypoxic-ischemic brain injury but also activates the anti-ferroptosis system.

Comparative study on the dynamic properties of lightweight porous concrete.

In this paper, two types of lightweight porous concrete material, expanded polystyrene concrete (EPSC) and ceramics-cement based porous material (CCPM) have been prepared on the base of C60 concrete. The dynamic mechanical experiments of lightweight porous concretes have been carried out by Φ 100 mm split Hopkinson pressure bar (SHPB) improved by wave shaping technology. The dynamic properties, including strength properties, deformation properties, impact toughness and energy absorption properties, of lightweight porous concretes have been analyzed comparatively, and its application prospects have been discussed. The results show that the two types of lightweight porous concretes are strain rate sensitive. Dynamic compression strength increases with strain rate; the correlation between the peak strain, ultimate strain of lightweight porous concrete and strain rate can be expressed by quadratic polynomial; under the impact loading, the impact toughness of lightweight porous concretes increases with strain rate, the amount of absorbed energy increases with the average incident energy change rate, moreover, the relation between the impact toughness and strain rate, and that between the amount of absorbed energy and the average incident energy change rate can both be expressed by exponential functions; compared with EPSC, CCPM has better properties in terms of strength, deformation, impact toughness and energy absorption. Those advantages are more obvious with high strain rate. Therefore, CCPM has more vast application prospects in civil defense projects than EPSC.