The development of a nurse-led preoperative anaesthesia screening tool by Delphi consensus

BACKGROUND

Low- and middle-income countries have a critical shortage of specialist anaesthetists. Most patients arriving for surgery are of low perioperative risk. Without immediate access to preoperative specialist care, an appropriate interim strategy may be to ensure that only high-risk patients are seen preoperatively by a specialist. Matching human resources to the burden of disease with a nurse-administered pre-operative screening tool to identify high-risk patients who might benefit from specialist review prior to the day of surgery may be an effective strategy.

OBJECTIVE

To develop a nurse-administered preoperative anaesthesia screening tool to identify patients who would most likely benefit from a specialist review before the day of surgery, and those patients who could safely be seen by the anaesthetist on the day of surgery. This would ensure adequate time for optimisation of high-risk patients preoperatively and limit avoidable day-of-surgery cancellations.

METHODS

A systematic review was conducted to identify preoperative screening questions for use in a three-round Delphi consensus process. A panel of 16 experienced full-time clinical anaesthetists representing all university-affiliated anaesthesia departments in South Africa participated to define a nurses' screening tool for preoperative assessment.

RESULTS

Ninety-eight studies were identified, which generated 79 questions. An additional 14 items identified by the facilitators were added to create a list of 93 questions for the first round. The final screening tool consisted of 81 questions, of which 37 were deemed critical to identify patients who should be seen by a specialist prior to the day of surgery.

CONCLUSION

A structured nurse-administered preoperative screening tool is proposed to identify high-risk patients who are likely to benefit from a timely preoperative specialist anaesthetist review to avoid cancellation on the day of surgery.

267 Dual checkpoint blockade of CD47 and PD-L1 using an affinity-tuned bispecific antibody maximizes anti-tumor immunity and improves therapeutic window

Background

T cell checkpoint immunotherapies have shown promising results in the clinic, but most patients remain non-responsive. CD47-SIRPα myeloid checkpoint blockade has shown early clinical activity in hematologic malignancies. However, CD47 expression on peripheral blood limits αCD47 antibody selectivity and thus efficacy in solid tumors.

Methods

To improve the antibody selectivity and therapeutic window, we developed a novel affinity-tuned bispecific antibody targeting CD47 and PD-L1 to antagonize both innate and adaptive immune checkpoint pathways. This PD-L1-targeted CD47 bispecific antibody was designed with potent affinity for PD-L1 and moderate affinity for CD47 to achieve preferential binding on tumor and myeloid cells expressing PD-L1 in the tumor microenvironment (TME).

Results

The antibody design reduced binding on red blood cells and enhanced selectivity to the TME, improving the therapeutic window compared to αCD47 and its combination with αPD-L1 in syngeneic tumor models. Mechanistically, both myeloid and T cells were activated and contributed to anti-tumor activity of αCD47/PD-L1 bispecific antibody. Distinct from αCD47 and αPD-L1 mono- or combination therapies, single-cell RNA sequencing (scRNA-seq) and gene expression analysis revealed that the bispecific treatment resulted in unique innate activation, including Pattern Recognition Receptor (PRR)-mediated induction of type I IFN pathways and antigen presentation in DCs and macrophage populations. Furthermore, treatment increased the Tcf7+ stem-like CD8 T cell population in the TME and promoted its differentiation to an effector-like state. Consistent with mouse data, the compounds were well tolerated and demonstrated robust myeloid and T cell activation in non-human primates (NHPs). Notably, RNAseq analysis in NHPs provided evidence that the innate immune activation was mainly contributed by CD47-SIRPα but not PD-L1-PD-1 blockade from the bispecific antibody.

Conclusions

These findings provide novel mechanistic insights into how myeloid and T cells can be uniquely modulated by the dual innate and adaptive checkpoint antibody and demonstrate its potential in clinical development (NCT04881045) to improve patient outcomes over current PD-(L)1 and CD47-targeted therapies.

Dual checkpoint blockade of CD47 and PD-L1 using an affinity-tuned bispecific antibody maximizes antitumor immunity

BACKGROUND

T cell checkpoint immunotherapies have shown promising results in the clinic, but most patients remain non-responsive. CD47-signal regulatory protein alpha (SIRPα) myeloid checkpoint blockade has shown early clinical activity in hematologic malignancies. However, CD47 expression on peripheral blood limits αCD47 antibody selectivity and thus efficacy in solid tumors.

METHODS

To improve the antibody selectivity and therapeutic window, we developed a novel affinity-tuned bispecific antibody targeting CD47 and programmed death-ligand 1 (PD-L1) to antagonize both innate and adaptive immune checkpoint pathways. This PD-L1-targeted CD47 bispecific antibody was designed with potent affinity for PD-L1 and moderate affinity for CD47 to achieve preferential binding on tumor and myeloid cells expressing PD-L1 in the tumor microenvironment (TME).

RESULTS

The antibody design reduced binding on red blood cells and enhanced selectivity to the TME, improving the therapeutic window compared with αCD47 and its combination with αPD-L1 in syngeneic tumor models. Mechanistically, both myeloid and T cells were activated and contributed to antitumor activity of αCD47/PD-L1 bispecific antibody. Distinct from αCD47 and αPD-L1 monotherapies or combination therapies, single-cell RNA sequencing (scRNA-seq) and gene expression analysis revealed that the bispecific treatment resulted in unique innate activation, including pattern recognition receptor-mediated induction of type I interferon pathways and antigen presentation in dendritic cells and macrophage populations. Furthermore, treatment increased the Tcf7⁺ stem-like progenitor CD8 T cell population in the TME and promoted its differentiation to an effector-like state. Consistent with mouse data, the compounds were well tolerated and demonstrated robust myeloid and T cell activation in non-human primates (NHPs). Notably, RNA-seq analysis in NHPs provided evidence that the innate activation was mainly contributed by CD47-SIRPα but not PD-L1-PD-1 blockade from the bispecific antibody.

CONCLUSION

These findings provide novel mechanistic insights into how myeloid and T cells can be uniquely modulated by the dual innate and adaptive checkpoint antibody and demonstrate its potential in clinical development (NCT04881045) to improve patient outcomes over current PD-(L)1 and CD47-targeted therapies.

Coexpression of CD71 and CD117 Identifies an Early Unipotent Neutrophil Progenitor Population in Human Bone Marrow

Neutrophils are the most abundant peripheral immune cells and thus, are continually replenished by bone marrow-derived progenitors. Still, how newly identified neutrophil subsets fit into the bone marrow neutrophil lineage remains unclear. Here, we use mass cytometry to show that two recently defined human neutrophil progenitor populations contain a homogeneous progenitor subset we term "early neutrophil progenitors" (eNePs) (Lin^-CD66b⁺CD117⁺CD71⁺). Surface marker- and RNA-expression analyses, together with in vitro colony formation and in vivo adoptive humanized mouse transfers, indicate that eNePs are the earliest human neutrophil progenitors. Furthermore, we identified CD71 as a marker associated with the earliest neutrophil developmental stages. Expression of CD71 marks proliferating neutrophils, which were expanded in the blood of melanoma patients and detectable in blood and tumors from lung cancer patients. In summary, we establish CD117⁺CD71⁺ eNeP as the inceptive human neutrophil progenitor and propose a refined model of the neutrophil developmental lineage in bone marrow.

Identification of a CD117+CD71+ early neutrophil progenitor population in human bone marrow

Neutrophils play critical roles in health and disease. Due to their very short half-life in blood and tissue, neutrophils are constantly replenished by bone-marrow progenitors. Thus, a comprehensive understanding of bone marrow neutrophil development is of paramount importance to identify how neutrophil production is altered in disease. Recently, two novel human neutrophil progenitor populations were identified; ‘human neutrophil progenitor’ or ‘hNeP’ (Lin-CD66b+CD117+) and ‘neutrophil precursor’ or ‘preNeu’ (Lin-CD66b+CD15+CD49d+). How these subsets fit into the neutrophil lineage is unclear. By using mass and flow cytometry, we show that hNeP are a heterogenous population containing a homogeneous progenitor subset termed ‘early neutrophil progenitor’ or ‘eNeP’ (Lin-CD66b+CD117+CD71+). Surface marker and RNA expression, together with the ability to form colonies in vitro suggest that eNePs, which constitute only ~0.14% of bone marrow neutrophils, are upstream of preNeu (~5% of bone marrow neutrophils). Furthermore, we have identified novel neutrophil surface markers associated with distinct developmental stages, including CD71. Intriguingly, CD71+ characterizes proliferating neutrophils, which are expanded in the blood of melanoma and lung cancer patients and detectable in human lung tumors. Collectively, our findings i) identify CD117+CD71+ eNeP as an early neutrophil progenitor population, ii) introduce a unified model of human neutrophil bone marrow development, iii) identify novel surface markers for distinct neutrophil developmental stages and iv) provide evidence for neutrophil progenitor expansion in cancer.

The non-receptor protein tyrosine kinase Pyk2 promotes the turnover of mouse monocyte populations at steady-state

Peripheral monocytes, consisting of distinct Ly6C+ and Ly6Cneg subsets in mice, are innate immune effector cells that exhibit a relatively short half-life of 1–3 days. While the differentiation and function of these monocyte subpopulations have been explored extensively, the cellular mechanisms regulating the maintenance and turnover of these populations are not completely understood. The focus of our current study is to investigate the role of proline-rich tyrosine kinase 2 (Pyk2) in the establishment and/or maintenance of monocyte populations at steady-state.

Using a Pyk2 knock-out mouse model (Pyk2−/−), we show for the first time that Pyk2−/− mice exhibit reduced bone marrow (BM) cellularity, resulting in a reduction of total BM monocytes in these mice. Accordingly, Pyk2−/− mice display reduced numbers of BM monocyte progenitors and Ly6C+ monocytes; however, there is no reduction in the representation of Ly6Cneg monocytes in the absence of Pyk2, suggesting that Pyk2 regulates the relative proportion of monocyte subsets normally represented in the BM at steady state. In support of this conclusion, a similar phenotype was observed in the peripheral blood and spleen. Data from reciprocal and mixed BM chimera experiments indicate that the alterations in monocyte populations exhibited by Pyk2−/− mice are due to factors intrinsic to the monocytes. Pyk2 does not appear to regulate the proliferation, differentiation, or egress of monocyte subsets. Instead, experiments using annexin V and cleaved caspase as markers for apoptosis indicate that Pyk2 may promote apoptosis in BM monocytes, thereby acting as an important regulator of turnover in these short-lived effector cells.

Abstract 2879: Expression of Focal Adhesion Kinase (FAK) in myeloid lineage cells increases with maturation and regulates primary tumor growth in MMTV-PyVmT murine model of breast cancer

Myeloid lineage cells are critical mediators of innate immunity that contribute to the inflammatory environment associated with tumor formation and progression. Our research explores the role of adhesion signaling through Focal Adhesion Kinase (FAK) in myeloid lineage cells as a potential regulator of breast tumor outgrowth. Previously, we have demonstrated that recruitment of cd11b-positive monocytes to sites of thioglycollate-induced inflammation was impaired in the absence of FAK. Additionally, we showed that bone marrow-derived macrophages exhibit reduced migration toward chemotactic factors commonly found in the breast tumor milieu. Given these results, the goal of the current study is to address the fundamental contribution of FAK toward myeloid cell functions that regulate breast tumor growth and progression. Mice with FAK conditionally deleted in myeloid lineage cells (FAKΔmyeloid) were crossed with mice that develop spontaneous breast carcinomas due to expression of the MMTV-PyMT transgene. FAKΔmyeloid MMTV-PyMT mice showed significantly enhanced primary tumor outgrowth compared to wildtype (WT) littermate MMTV-PyMT animals. Tumors from both genotypes contained equivalent numbers of mature, F4/80-positive tumor-associated macrophages (TAMs), demonstrating that these cells were not dependent upon FAK to infiltrate/survive in the tumor. This was reinforced by adoptive transfer studies showing equal numbers of WT and FAKΔmyeloid bone marrow monocytes at the tumor site 30 minutes post-injection. Further analysis revealed that FAK expression was developmentally regulated, such that bone marrow cells and the immature Ly6C+cd11b+ cells present in circulation expressed nearly undetectable amounts of FAK protein. However, a substantial number of the cd11b+ cells within the tumor were Lyc6C-negative and had gained expression of FAK. Interestingly, the Ly6C-negative cells were shown to be more migratory than the Lyc6C+ monocytes, and this increased migration was dependent upon FAK expression. Based on these data, we propose that monocytes mature and upregulate FAK once they have successfully extravasated out of the tumor vasculature. This, in turn, allows increased movement of these cells within the tumor microenvironment, which may help to control tumor size/outgrowth through more effective clearance of necrotic cells and/or more global distribution of factors that could ultimately mediate an anti-tumor effect. Experiments are currently underway to test these possibilities.

Citation Format: Ryan Llewellyn, Michael F. Gutknecht, Amy H. Bouton. Expression of Focal Adhesion Kinase (FAK) in myeloid lineage cells increases with maturation and regulates primary tumor growth in MMTV-PyVmT murine model of breast cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2879. doi:10.1158/1538-7445.AM2013-2879

A report of the natural history of leptomeningeal gliomatosis

Primary leptomeningeal gliomatosis (PLG) is a rare condition, with fewer than 50 patients reported. Our report illustrates the natural history of PLG in full, from the prodromal phase of subacute meningitis to the final stages characterised by extensive nerve root infiltration, cranial nerve palsies and widespread peripheral neurogenic muscle wasting. We provide correlative neuroimaging with serial MRI, and present the first published positron emission tomography imaging of this condition. We emphasise the importance of considering PLG in the differential diagnosis of chronic aseptic meningitis, the difficulties of making the diagnosis ante mortem, and the utility and potential limitations of early meningeal biopsy in this condition.

How good are the maternity services for 'drug misusers' in England and Wales? A national survey

To assess the state of maternity services for pregnant drug misusers, a postal questionnaire-based survey was carried out in England and Wales in 2005. A total of 222 questionnaires were sent with a response rate of 80.63%, reporting a total of 5,324 births to drug-misusers. Data were collated and analysed using Microsoft Excel 2003. Despite improvement in the services provided to the pregnant drug-misusers, there is wide regional variation. Hepatitis-C screening is particularly under-offered. Pre-birth meetings appear to be the way forward to optimise overall outcome. Maternity-unit staff need appropriate training for providing sufficient knowledge of drug use and its consequences for the pregnancy.

The proseal laryngeal mask: results of a descriptive trial with experience of 300 cases

BACKGROUND

The ProSeal laryngeal mask airway (PLMA) is a new laryngeal mask device with a modified cuff and a drainage tube.

METHODS

We assessed the PLMA in 300 anaesthetized adults either paralysed or breathing spontaneously. We assessed insertion characteristics, airway seal pressures, haemodynamic response to insertion, ease of gastric tube placement, gastric insufflation, and postoperative sore throat.

RESULTS

Insertion was successful in 294 patients (98%) and graded as easy in 274 patients (91%). We found no difference in ease of insertion or success rate with either the introducer or the finger insertion method, or in paralysed or non-paralysed patients. Mean airway seal pressure was 29 cm H2O, and 59 patients (20%) had seal pressures greater than 40 cm H2O. No gastric insufflation was detected. Gastric tube placement was successful in 290 of 294 patients (98.6%). There was no cardiovascular response to insertion, with a small reduction in heart rate 5 min after insertion and significant decreases in mean arterial pressure at 1 and 5 min after insertion. Sore throat was noted in 23% patients after operation and in 16% of patients after 24 h, with 90% of the sore throats described as mild.

CONCLUSIONS

The PLMA is a reliable airway management device that can give an effective glottic seal in paralysed and non-paralysed patients. The device allows the easy passage of a gastric tube, causes a minimal haemodynamic response to insertion, and an acceptable incidence of sore throat.

Future health services--a challenge for disabled people

Living as a disabled person in our society raises many challenges--physical, economic, political. The struggle by disabled people to escape the medical model and enter the paths of integration have not been easy. This paper explores options for participation and consumer impact.