A high-throughput two-cell assay for interrogating inhibitory signaling pathways in T cells

The recent success of immunotherapies relying on manipulation of T-cell activation highlights the value of characterising the mediators of immune checkpoint signaling. CRISPR/Cas9 is a popular approach for interrogating signaling pathways; however, the lack of appropriate assays for studying inhibitory signaling in T cells is limiting the use of large-scale perturbation-based approaches. Here, we adapted an existing Jurkat cell-based transcriptional reporter assay to study both activatory and inhibitory (PD-1-mediated) T-cell signaling using CRISPR-based genome screening in arrayed and pooled formats. We targeted 64 SH2 domain-containing proteins expressed by Jurkat T cells in an arrayed screen, in which individual targets could be assessed independently, showing that arrays can be used to study mediators of both activatory and inhibitory signaling. Pooled screens succeeded in simultaneously identifying many of the known mediators of proximal activating and inhibitory T-cell signaling, including SHP2 and PD-1, confirming the utility of the method. Altogether, the data suggested that SHP2 is the major PD-1-specific, SH2 family mediator of inhibitory signaling. These approaches should allow the systematic analysis of signaling pathways in T cells.

The current state and future of T-cell exhaustion research

'Exhaustion' is a term used to describe a state of native and redirected T-cell hypo-responsiveness resulting from persistent antigen exposure during chronic viral infections or cancer. Although a well-established phenotype across mice and humans, exhaustion at the molecular level remains poorly defined and inconsistent across the literature. This is, in part, due to an overreliance on surface receptors to define these cells and explain exhaustive behaviours, an incomplete understanding of how exhaustion arises, and a lack of clarity over whether exhaustion is the same across contexts, e.g. chronic viral infections versus cancer. With the development of systems-based genetic approaches such as single-cell RNA-seq and CRISPR screens applied to in vivo data, we are moving closer to a consensus view of exhaustion, although understanding how it arises remains challenging given the difficulty in manipulating the in vivo setting. Accordingly, producing and studying exhausted T-cells ex vivo are burgeoning, allowing experiments to be conducted at scale up and with high throughput. Here, we first review what is currently known about T-cell exhaustion and how it's being studied. We then discuss how improvements in their method of isolation/production and examining the impact of different microenvironmental signals and cell interactions have now become an active area of research. Finally, we discuss what the future holds for the analysis of this physiological condition and, given the diversity of ways in which exhausted cells are now being generated, propose the adoption of a unified approach to clearly defining exhaustion using a set of metabolic-, epigenetic-, transcriptional-, and activation-based phenotypic markers, that we call 'M.E.T.A'.

811 DELIRIUM IN COVID-19: COMMON AND CLINICALLY SIGNIFICANT: EXPERIENCES FROM THE NIGHTINGALE HOSPITAL EXETER

Background

Delirium is an independent predictor of mortality in patients admitted with community-acquired pneumonia (Pieralli, 2014), but significance and incidence in Covid-19 infection has not been established. The Nightingale Hospital Exeter (NHE) as a multidisciplinary team model, managed 242 patients with Covid-19 from November 2020 to February 2021. This study identifies the delirium incidence, outcome, premorbid function and demographics of this cohort.

Methods

Electronic records were retrospectively reviewed for keywords ‘Delirium’, ‘Hyperactive’, ‘Hypoactive’, ‘Confused’ and ‘Muddled’. Patients were categorised as Hyperactive, Hypoactive or Confused/non-specified. Prior functional support (independent, package of care, residential or nursing care) and presence of pre-established neurological conditions (including dementia) were noted.

Results

242 patients were included, average age 84 years (range 59–102). Of these patients, 130 (54%) developed delirium (29 (22%) hyperactive, 37 (28%) hypoactive, 2 (1%) mixed and 62 (48%) ‘confused’/non-specified). Of those with delirium, 56 (43%) were previously living independently and 51 (39%) were living at home with a package of care. 60 (46%) of those diagnosed had no pre-existing neurological condition, 32% had underlying dementia. There were 37 deaths at NHE (mortality 15%), 73% of these patients had delirium during their admission compared to 50% of those who survived.

Conclusions

Over half this cohort developed delirium, a high proportion of whom had been living independently prior to admission with no pre-existing neurological condition, emphasising how common delirium is in patients with Covid-19. In a comparable cohort with pneumonia (mean age 82 years, range 65–99) 25% developed delirium, and it was an independent predictor of in-hospital mortality (Pieralli, 2014). The fact that 73% of all patients who died developed delirium suggests it may have important prognostic implications, and both this and the high incidence indicate further work is required to fully understand how to prevent and manage delirium in Covid-19.

Starting treatment according to guidelines evaluation: a multicentre audit of HIV patients in the UK

The aim of this audit was to assess whether HIV patients are being started on antiretroviral therapy (ART) according to British and European guidelines. Data were collected from the Survey of Prevalent HIV Infections Diagnosed (SOPHID) return for 2010 at five major HIV management centres in the UK. Data from this 3873 patient cohort revealed 52 patients who should have been receiving ART according to the guidelines but were not. Of these, 23 patients elected not to start ART despite clinical advice to the contrary. Information required to assist in the decision for earlier ART initiation (CD4 count 350–500 cells/mL) was missing for some patients. Clinicians must pay attention to the regular assessment of patients with a CD4 count of 351–500 cells/mL so that all those who may benefit from earlier treatment are identified. Future research should investigate patient barriers to initiating therapy following recommendation by a clinician.

A review of HIV postexposure prophylaxis provision at a genitourinary medicine department

We undertook a retrospective case-note audit of all patients who presented to the Edinburgh genitourinary (GU) medicine department following a potential exposure to HIV infection during the period 1 January 2006 to 31 December 2008. Over the audit period, 81 individuals attended the department, in relation to 85 exposure events. Twenty-three (27%) exposures had occurred in a health-care occupational setting and 50 (59%) in a sexual context. Baseline HIV testing was only performed in 38 (45%) of the 85 exposures. Postexposure prophylaxis (PEP) was initiated in 65 (76%) cases: 61 (94%) received the first dose within the recommended 72 hours. In 68 (80%) of the 85 exposures, the PEP initiation decision tallied with guideline recommendations. Fifty-six of the 65 individuals started on PEP continued beyond 72 hours; 53 of them were reviewed at least once during the course of PEP and had routine blood monitoring performed. Documentation regarding adherence was poor, with only 31 having this recorded in notes. Thirty-seven (66%) individuals who continued on PEP attended for follow-up HIV testing at three months. In summary, the department performed well in some aspects of PEP provision. However, baseline HIV testing and documentation regarding adherence are unsatisfactory and we suggest recommendations to improve this.

The effects of 41°C hyperthermia on the DNA repair protein, MRE11, correlate with radiosensitization in four human tumor cell lines

PURPOSE

The goal of this study was to determine if reduced availability of the DNA repair protein, MRE11, for the repair of damaged DNA is a basis for thermal radiosensitization induced by moderate hyperthermia. To test this hypothesis, we measured the total amount of MRE11 DNA repair protein and its heat-induced alterations in four human tumor cell lines requiring different heating times at 41 degrees C to induce measurable radiosensitization.

MATERIALS AND METHODS

Human colon adenocarcinoma cell lines (NSY42129, HT29 and HCT15) and HeLa cells were used as the test system. Cells were irradiated immediately after completion of hyperthermia. MRE11 levels in whole cell extract, nuclear extract and cytoplasmic extracts were measured by Western blotting. The nuclear and cytoplasmic extracts were separated by TX100 solubility. The subcellular localization of MRE11 was determined by immunofluorescence staining.

RESULTS

The results show that for the human tumor cell lines studied, the larger the endogenous amount of MRE11 protein per cell, the longer the heating time at 41 degrees C required for inducing measurable radiosensitization in that cell line. Further, the residual nuclear MRE11 protein level, measured in the nuclear extract and in the cytoplasmic extract as a function of heating time, both correlated with the thermal enhancement ratio (TER).

CONCLUSIONS

These observations are consistent with the possibility that delocalization of MRE11 from the nucleus is a critical step in the radiosensitization by moderate hyperthermia.

Direct and indirect bacterial killing functions of neutrophil defensins in lung explants

Studies of the antimicrobial activity of neutrophil defensins have mostly been carried out in microbiological media, and their effects on the host defense in physiological conditions are unclear. We examined 1) the antibacterial activity of defensins in physiological media with and without lung tissue present, 2) the effect of defensins on hydrogen peroxide (H(2)O(2)) production by lung tissue that had been exposed to bacteria, and 3) the effect of diphenyleneiodonium (DPI), an inhibitor of reactive oxygen species formation, on the antibacterial activity of defensins in the presence of lung tissue. Defensins were incubated with Escherichia coli or Pseudomonas aeruginosa in the absence or presence of primary cultured mouse lung explants. Defensins reduced bacterial counts by approximately 65-fold and approximately 25-fold, respectively, at 48 h; bacterial counts were further decreased by approximately 600-fold and approximately 12,000-fold, respectively, in the presence of lung tissue. Defensins induced H(2)O(2) production by lung tissue, and the rate of killing of E. coli by defensins was reduced by approximately 2,500-fold in the presence of 10 microM DPI. We conclude that defensins exert a significant antimicrobial effect under physiological conditions and that this effect is enhanced in the presence of lung tissue by a mechanism that involves the production of reactive oxygen species.

Ethics in the classroom: a reflection on integrating ethical discussions in an introductory course in computer programming

In this paper, we describe our recent approaches to introducing students in a beginning computer science class to the study of ethical issues related to computer science and technology. This consists of three components: lectures on ethics and technology, in-class discussion of ethical scenarios, and a reflective paper on a topic related to ethics or the impact of technology on society. We give both student reactions to these aspects, and instructor perspective on the difficulties and benefits in exposing students to these ideas.

Autonomy and competency--self-determination in the lives of adults with developmental disabilities

The principle of autonomy anchors decision making for most North Americans. For people with disabilities, however, the quest for self-determination is often countered by society's responsibility to take care of those who have some area of weakness or incompetence. Those who serve this population must, therefore, intentionally shift the balance of power to encourage independent living and to give people with disabilities a voice in their own lives. Changes in the system of care, training, and the way questions of competency are adjudicated are contemplated.

Coding component important element of compliance plan

In recent years the U.S. government has increased its fraud and abuse investigations in all sectors of the healthcare community. Healthcare providers that are successfully prosecuted may be excluded from the Medicare programs and are liable for monetary penalties. The best course of action is for providers to have a comprehensive compliance plan in place. An important element of such a plan is a component that will identify and address problematic coding issues.

Postmeningococcal lumbosacral radiculopathy

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Serum urate as a free radical scavenger in diabetics

We have looked at the relationship between serum urate and the molar equivalent serum antioxidant capacity (MESA) in diabetic and normal individuals who attended St Bartholomew's Hospital diabetic clinic and BUPA Health Screening Centre, London, and have compared serum antioxidant capacity between the two groups. Sample response curves showed less serum antioxidant potential in diabetics than in nondiabetics, and a linear relationship between serum urate and MESA. Simple regression analysis gave a correlation coefficient of 0.9 (p < 0.0001). Significant differences between the two groups were found for both mean MESA values (p < 0.0001) and mean uric acid levels (p < 0.005).

Carotid patch angioplasty: immediate and long-term results

To determine the benefit of carotid patch angioplasty, a retrospective study of 1000 consecutive carotid endarterectomies was done. Based on the type of carotid endarterectomy closure, patients were divided into four groups: 250 had primary closure, 250 had expanded polytetrafluoroethylene patch, 250 had Dacron patch, and 250 had saphenous vein patch. On the basis of operative technique or type of carotid artery closure, no statistical difference was found in the incidence of postoperative stroke (p greater than 0.25): primary closure 1.6% (4), expanded polytetrafluoroethylene 2.0% (5), Dacron patch 1.6% (4), and saphenous vein patch (0). Postoperative carotid patency was determined by B-mode ultrasonography, and 717 patients were evaluated in follow-up extending to 6 years (mean 37.8 months). Based on the method of carotid endarterectomy closure, no significant difference (p greater than 0.25) was found in the incidence of significant restenosis (greater than 50% diameter reduction): primary closure 4.0% (7), expanded polytetrafluoroethylene 4.0% (6), Dacron 5.4% (9), and saphenous vein 1.0% (2). Significant restenosis was most frequent in habitual smokers (93%, 25/28) and females (78%, 22/28) despite the method of carotid endarterectomy closure. No statistical difference was found in the incidence of late ipsilateral stroke either (p greater than 0.25): primary closure 2.9% (5), expanded polytetrafluoroethylene 2% (3), Dacron 5% (3), and saphenous vein 0%. These results indicate that the incidence of postoperative stroke, regardless of method of arterial closure, was not statistically different. The method of carotid closure did not appear to affect the occurrence of late ipsilateral stroke or restenosis; however, patch angioplasty with saphenous vein appears appropriate in habitual smokers, and likely in patients with small internal carotid arteries.

One path to a comprehensive district psychiatric service

Brighton, which never had its own large psychiatric hospital, now has a comprehensive community psychiatric service. Sarah Hood and Tony Whitehead describe the development of the service and argue that the closure of large hospitals need not and should not result in the neglect or exploitation of former patients.

Sequential development of aneuploidy, keratin modifications, and gamma-glutamyltransferase expression in mouse skin papillomas

To elucidate the role and timing of expression of different premalignant and malignant markers in tumor promotion, we correlated alterations in keratin patterns and gamma-glutamyltransferase (GGT) expression with the chromosomal status of individual mouse skin papillomas. Papillomas were induced by 7,12-dimethylbenz[a]anthracene initiation and 12-O-tetradecanoylphorbol-13-acetate promotion. Individual tumors were randomly sampled at 20 and 35 weeks of promotion. Each tumor was cytogenetically analyzed and serial paraffin sections were used for GGT detection, immunoblotting, and immunohistochemistry studies. Monospecific antibodies elicited against keratins K1 (Mr 67,000) and K14 (Mr 55,000) were used to analyze keratin modifications. Most tumors at 20 weeks of promotion, although exhibiting aneuploidy, still presented high levels of the K1 differentiation-associated keratin. Later during promotion those tumors bearing the highest aneuploidy indexes were those that showed a marked decrease in or absence of the K1 protein. Furthermore, those same tumors with the highest levels of genomic alterations also exhibited foci of GGT activity. These results support the idea that the majority of papillomas under continuous promotion are progressing toward malignancy. Aneuploidy seems to precede detectable keratin modifications, and GGT activity appears to be the latest marker to be expressed.

A novel technique for assessing the sources of dietary sodium

Li can be used to track Na during the cooking and eating process as it is handled by the body in a manner similar to Na. A new approach to study the sources of salt using Li is described. When this technique was applied in an epidemiological context using 12 consecutive 24-hour urine collections, we found that at least 83% of the salt ingested by a population in Cambridgeshire, England, was derived from processed food. Only a small amount of the total salt intake came from cooking or from using salt on the table. The total amount of salt eaten was not as high as was previously estimated indirectly. There was a clear sex difference in salt intake which in part related simply to the finding that salt intake correlates with body weight of an individual. This study implies that those who wish to advocate a reduction in salt intake in order to prevent hypertension must reconsider their approach. Any health education programme that is geared simply to reduce discretionary salt use in the home, will have little impact on the total amount of NaCl ingested by the population.

A single-ward approach to the elderly mentally ill

A service for the elderly mentally ill is described which is based in a general hospital complex and combines a heavy community commitment with the use of two all-purpose inpatient wards and two associated day hospitals. Each ward functions as an admission, treatment, rehabilitation, and medium- and long-stay facility. Experience suggests that this system makes it possible to cater for the elderly mentally ill in a population with many fewer beds than the recommended norm and is a better insurance against unnecessary prolonged hospitalization than "progressive patient care".

Hospital life: when it works it works well

Although it is now generally accepted that the best place to treat old people is in their own homes it is sometimes necessary for them to have some sort of institutional care. This poses the question of whether it is better to care for them in hospital, in old people's homes, or with community support, in day hospitals and day centres. Tony Whitehead looks at schemes in East Sussex which cover a catchment area including Brighton.