DIALOR (DIgitAL cOaching for fRailty): protocol for a single-arm mixed-methods feasibility study of a digital health coaching intervention for older people with frailty in primary care

BACKGROUND

Multidomain interventions in older adults offer the best opportunity to prevent, delay or reverse existing symptoms in the earlier stages of frailty and improve independence but can be costly, and difficult to deliver at scale. However, digital health interventions enable personalised care and empowerment through self-management of long-term conditions, used at any time and when combined with health coaching offer the potential to enhance well-being and facilitate the achievement of health-related goals. We aim to evaluate the feasibility and acceptability of a digital health platform for long-term disease management combined with health coaching for people living with mild-moderate frailty, targeting self-identified goals-activity, nutrition, mood, enhancing social engagement and well-being.

METHODS AND ANALYSIS

This is a non-randomised feasibility, single-group, pretest/post-test study, using qualitative and quantitative methods. The digital health coaching intervention (DIALOR-DIgitAL cOaching for fRailty) has been developed for implementation to older adults, aged 65 years or older with mild to moderate frailty and diagnosis of one or more long-term health conditions in the community. Participants will receive 12 weeks of health coaching and have access to a mobile health platform for 6 months. The primary outcome measure is the acceptability and feasibility of DIALOR along with a range of secondary outcome measures (including frailty, functioning measures, quality of life, social engagement, diet quality and self-reported indicators) collected at baseline and at 6 months. The findings will inform whether a wider effectiveness trial is feasible and if so, how it should be designed.

ETHICS AND DISSEMINATION

Ethical approval has been granted by the Southeast Scotland Research Ethics Committee 02 (reference: 22/SS/0064). Research findings will be disseminated in a range of different ways to engage different audiences, including publishing in open-access peer-reviewed journals, conference presentations, social media, dissemination workshop with patients, carers, and healthcare professionals and on institution websites.

The changing role of Advanced Clinical Practitioners working with older people during the COVID- 19 pandemic: A qualitative research study

BACKGROUND

COVID-19 was identified as a pandemic by the World Health Organisation (WHO) in December 2020. Advanced Clinical Practitioners (ACPs) in England working with older people with frailty, experienced their clinical role changing in response to the emergency health needs of this complex population group. In contrast to other countries, in England Advanced Clinical Practitioners are drawn from both nursing and allied health professions. Whilst much of the literature emphasises the importance of ensuring the sustainability of the Advanced Clinical Practitioners' role, the pandemic threw further light on its potential and challenges. However, an initial review of the literature highlighted a lack of research of Advanced Clinical Practitioners' capabilities working with uncertainty in disaster response situations.

AIM

To capture the lived experience of how English Advanced Clinical Practitioners working with older people adapted their roles in response to the COVID-19 pandemic (October 2020-January 2021).

DESIGN, SETTING AND PARTICIPANTS

A qualitative research design was used. Following ethical approval, 23 Advanced Clinical Practitioner volunteer participants from across England with varied health professional backgrounds were recruited from Advanced Clinical Practitioners' professional and social media networks on Twitter using a snowballing technique.

METHODS

Depending on preference or availability, 23 participants (nurses (18), physiotherapists (2), paramedics (2) and a pharmacist (1)) were interviewed singularly (n = 9) or as part of 3 focus groups (n = 14) using Zoom video communication. Audio recordings were transcribed and using qualitative data analysis software, NVivo 12 pro, coded for an essentialist thematic analysis of Advanced Clinical Practitioners' responses using an inductive approach. 27 codes were identified and collated into five themes. For the purposes of this paper, four themes are discussed: experiencing different work, developing attributes, negotiating barriers and changing future provision.

FINDINGS

Advanced Clinical Practitioners successfully transferred their advanced practice skills into areas of clinical need during the pandemic. Their autonomous and generic, high level of expertise equipped them for management and leadership positions where speed of change, and the dissolution of traditional professional boundaries, were prioritised. Barriers to progress included a lack of knowledge of the Advanced Clinical Practitioner role and friction between Advanced Clinical Practitioners and physicians.

DISCUSSION AND CONCLUSION

The study demonstrated the successful adaption of the Advanced Clinical Practitioner role to enable more creative, personalised and sustainable solutions in the care of older people living with frailty during the pandemic. The potential of Advanced Clinical Practitioner development is in a juxtaposition to the threat of pandemic services being dismantled once the emergency nature of care has passed. Healthcare organisations have a vital part to play in considering the enablers and barriers of Advanced Clinical Practitioner capability-based practice when responding to uncertainty.

Barriers and enablers to implementing 'DEALTS2' simulation-based train-the-trainer dementia training programme in hospital settings across England: a qualitative study

Background

Despite approaches to provide effective dementia training in acute care settings, little is known about the barriers and enablers to implement and embed learning into practice. We were commissioned by Health Education England to develop and evaluate a new dementia training intervention ‘Dementia Education And Learning Through Simulation 2’ (DEALTS2), an innovative simulation toolkit to support delivery of dementia training in acute care across England. This study aimed to explore barriers and enablers experienced by trainers implementing DEALTS2 and extent to which it impacted on delivery of training and staff clinical practice.

Methods

We conducted twelve one-day DEALTS2 train-the-trainer (TTT) workshops across England in 2017 for National Health Service Trust staff employed in dementia training roles (n = 199 trainers); each receiving a simulation toolkit. Qualitative data were collected through telephone interviews 6–8 months after TTT workshops with 17 of the trainers. Open ended questions informed by the Kirkpatrick model enabled exploration of implementation barriers, enablers, and impact on practice.

Results

Thematic analysis revealed six themes: four identified interrelated factors that influenced implementation of DEALTS2; and two outlined trainers perceived impact on training delivery and staff clinical practice, respectively: (i) flexible simulation and implementation approach (ii) management support and adequate resources (iii) time to deliver training effectively (iv) trainer personal confidence and motivation (v) trainers enriched dementia teaching practice (vi) staff perceived to have enhanced approach to dementia care. Trainers valued the DEALTS2 TTT workshops and adaptability of the simulation toolkit. Those supported by management with adequate resources and time to deliver effective dementia training, were likely to implement DEALTS2. Trainers described positive impacts on their teaching practice; and perceived staff had enhanced their approach to caring for people with dementia.

Conclusions

Trainers explained individual and organisational barriers and enablers during implementation of DEALTS2. The flexible simulation and implementation approach were key to supporting adherence of DEALTS2. To ensure wider implementation of DEALTS2 nationally, Trusts need to allocate appropriate time to deliver effective dementia training. Future research should measure staff behaviour change, patient perspectives of the intervention, and whether and how DEALTS2 has improved health and care outcomes.

Impact of the COVID-19 pandemic on end of life care delivery in care homes: A mixed method systematic review

BACKGROUND

Current evidence suggests that COVID-19 is having a negative impact on the delivery of end of life care in care homes around the world. There is a need to collate current evidence to provide a comprehensive overview to assess extent of the problem.

AIM

To describe and evaluate the impact of the COVID-19 pandemic on end of life care delivery in care homes.

DESIGN

Systematic review and narrative synthesis of studies reporting qualitative and quantitative data.

DATA SOURCES

The databases MEDLINE, psycINFO, SCOPUS and CINAHL were searched between December 2019 and March 2021.

RESULTS

Nine studies were included. For care home staff, challenges included significant increases in responsibility and exposure to death, both of which have taken an emotional toll. Results indicate that staff tended not to be offered adequate emotional support or afforded the time to grieve. For those receiving end of life care, results indicate that the end of life care that they tended to receive, especially in the form of advance planning, was disrupted by the pandemic.

CONCLUSION

The effect of the pandemic has been to exacerbate existing problems in the provision of end of life care in care homes for both service providers and users, making that which was previously opaque starkly visible. Future research is needed to explore the effects of the pandemic and its management on those receiving end of life care in care homes and their significant others.

Developing a support group for carers of people living with dementia

Significant numbers of people in the UK care for someone living with dementia. Providing support for carers is socially and economically important, enabling them to continue in their caring role and improving their day-to-day experience of caring. This article comprises a reflection by one dementia nurse specialist who ran a six-week educational support group for carers of people living with dementia. It describes the development of the group and the challenges faced, as well as discussing the future of the group, including the need to ensure its sustainability through collaborative working. The article also details some of the positive outcomes described by carers who attended the group.

A critical realist evaluation of advance care planning in care homes

AIMS

To evaluate care planning in advance of end-of-life care in care homes.

DESIGN

A qualitative study.

METHODS

Qualitative data were collected from January 2018-July 2019 (using focus groups and semi-structured interviews) from three care homes in the South West of England. The data were analysed using thematic analysis followed by Critical Realist Evaluation.

RESULTS

Participants comprised of registered nurses (N = 4), care assistants (N = 8), bereaved relatives (N = 7), and domiciliary staff (N = 3). Although the importance of advance care planning was well recognized, the emotional labour of frequently engaging in discussions about death and dying was highlighted as a problem by some care home staff. It was evident that in some cases care home staff's unmet emotional needs led them to rushing and avoiding discussions about death and dying with residents and relatives. A sparsity of mechanisms to support care home staff's emotional needs was noted across all three care homes. Furthermore, a lack of training and knowledge appeared to inhibit care home staff's ability to engage in meaningful care planning conversations with specific groups of residents such as those living with dementia. The lack of training was principally evident amongst non-registered care home staff and those with non-formal caring roles such as housekeeping.

CONCLUSION

There is a need for more focused education to support registered and non-registered care home staff to effectively engage in sensitive discussions about death and dying with residents. Furthermore, greater emotional support is necessary to help build workforce resilience and sustain change.

IMPACT

Knowledge generated from this study can be used to inform the design and development of future advance care planning interventions capable of supporting the delivery of high-quality end-of-life care in care homes.

Impact of 'DEALTS2' education intervention on trainer dementia knowledge and confidence to utilise innovative training approaches: A national pre-test - post-test survey

BACKGROUND

Gaps in acute care staff knowledge, skills, and attitudes towards dementia exist. Innovative training approaches that improve the delivery of care for people with dementia are needed. We were commissioned by Health Education England to develop and evaluate a new dementia education intervention 'Dementia Education And Learning Through Simulation 2' (DEALTS2), a simulation toolkit to enhance delivery of dementia training nationally across England.

OBJECTIVES

Evaluate differences in trainer dementia knowledge scores pre and post training, satisfaction with DEALTS2 Train-The-Trainer (TTT) workshops and simulation toolkit, confidence to use training approaches, and spread of implementation.

DESIGN

A questionnaire survey using a pre-test - post-test design with measures completed: before (pre-test); after (T1); and 12 months post training (T2).

SETTING

Twelve one-day DEALTS2 TTT workshops delivered across England in 2017.

PARTICIPANTS

National Health Service Trust staff employed in dementia training roles (n = 199 trainers).

METHODS

Trainers attended DEALTS2 TTT workshops and received the simulation toolkit. Data were collected between 2017 and 2018 using a questionnaire capturing differences in dementia knowledge scores, Likert scales and closed-ended questions measured satisfaction, confidence and implementation. Data were analysed using quantitative methods.

RESULTS

Response rate was 92% (n = 183) at pre-test/T1 and 26% (n = 51) at T2. Trainer dementia knowledge scores increased from pre-test to T1 (p < 0.001) and were retained after 12 months in 5 of the 6 areas measured (pre-test to T2, p < 0.002); largest gains in 'humanised approaches to dementia care'. 96% (n = 176/183) were satisfied with DEALTS2 TTT workshops and simulation toolkit; 66.7% (n = 34/51) felt confident to deliver dementia training informed by DEALTS2. Adherence rates were good with 45% (n = 23/51) using the innovative training approaches within twelve months.

CONCLUSIONS

The results show DEALTS2 effectively increased trainer dementia knowledge and confidence to utilise innovative dementia training approaches. Implementation of DEALTS2 varied across organisations, therefore further research should explore factors determining successful implementation.

Compassionate care in the community: reflections of a student nurse

Reflecting on practice and analysing situations when compassionate care has been delivered can be a valuable way of helping student nurses develop their understanding of humanising care. This exemplar showcases a scenario when a second-year student nurse studying for a BSc (Honours) in adult nursing explored an experience while working in the community. She critically reflected on an incident highlighting a simple yet powerful example of how she helped an older couple manage an aspect of their care. This exercise helped the student to explore and understand what compassionate care means and highlighted how the value of reflection can be used to gain new insights to enhance the care of older people in her future practice in the community.

Systematic critical realist review of interventions designed to improve end-of-life care in care homes

The demand for high-quality end-of-life care is rising. Frequently evidenced concerns about the provision of end-of-life in care homes relate to inter-disciplinary communication and engagement in advance care planning. A number of interventions employing different mechanisms have been designed to address these issues. Therefore, the aim of this systematic critical realist review was to describe and explain the effectiveness of interventions designed to improve end-of-life care in care homes. Electronic searches were conducted in ScienceDirect, MEDLINE, PubMed, PsychINFO, and CINAHL from January 2000 to August 2018. Forty one studies were included in the review. While most of the evidence identified in this review was not strong, there was evidence to suggest that education and inter-professional collaboration can be effective intervention mechanisms for improving end-of-life care in care homes. High staff turnover was a significant contextual mechanism impacting on the sustainability of interventions. In terms of human agency, it is important to note a consistent finding related to the dedication and enthusiasm of care home staff who deliver end-of-life care.

What is an older husband's experience of caring for his wife who has dementia?

A significant number of informal carers look after people who have dementia. Women's caring experiences are well documented. However, a substantially smaller amount of research exists specifically investigating the male carer perspective. This literature review explores older husbands' experiences of caring for their wives who have dementia. The findings suggest that husbands are committed to their caring role but can feel socially isolated. The caring role of older men has altered the dynamic in the marriage. Husbands continue to show commitment towards their spouses but feel that male-only support groups could offer some respite from their responsibilities. Nurses need to take time to listen to husbands' experiences, offering emotional support and signposting them to other services. Further research on the long-term effects and support needs of older male carers is needed.

Better together: a day hospital's move towards integrated care

Background/Aims

This article will present how an interdisciplinary team working within a day hospital in an acute NHS Foundation Trust embraced the opportunities of practice development to work ‘better together’ to meet the complex needs of individuals using the service.

Methods

By working closely with key stakeholders, the team developed an integrated service intersecting both primary and secondary care boundaries.

Results

The principles of practice development, including shared vision and focus, ensured changes made to the service were patient centred. These changes included a 360-degree assessment by professional staff with extended skills beyond their own professional role, and a virtual ward round, where individual patients are reviewed by an interdisciplinary team in the community with a focus on avoiding hospital admission, with quicker access to the day hospital. The team worked closely with their local university towards achieving practice development unit status, demonstrating a rigorous approach to the development of services provided by the day hospital.

Conclusions

The article highlights both the value of practice development and significantly the value of an interdisciplinary team working within a day hospital setting.

Influences on clinical decision-making during a community placement: reflections of a student nurse

High quality care is dependent on good clinical judgement and often-complex decision making. Nurses need to be able to justify and defend their clinical decisions. In this article, a third-year nursing student reflects on an incident from a community placement involving a collaborative clinical decision. Carper's (1978) four fundamental patterns of knowing are used to analyse the decision-making process. It is shown that influences on decision-making include prior knowledge and expertise, law and accountability, and ethical principles such as respect for autonomy and beneficence. Good communication, interpersonal skills and a person-centred approach have a bearing on decision-making. It is argued that intuition also has a place and may be increasingly used with experience.

Widening participation in nurse education: An integrative literature review

BACKGROUND

Widening participation into higher education is espoused within educational policy in the UK, and internationally, as a mechanism to promote equality and social mobility. As nurse education is located within higher education it has a responsibility to promote widening participation within pre-registration educational programmes. It could also be argued that the profession has a responsibility to promote equality to ensure its' workforce is as diverse as possible in order to best address the health needs of diverse populations.

OBJECTIVES

To undertake an integrative review on published papers exploring Widening Participation in undergraduate, pre-registration nurse education in the UK.

DESIGN

A six step integrative review methodology was utilised, reviewing papers published in English from 2013-2016.

DATA SOURCES

Search of CINAHL, Education Source, MEDLINE, PsychINFO, SocINDEX, Science Direct, Business Source Complete, ERIC, British Library ETOS, Teacher Reference Centre, Informit Health Collection and Informit Humanities and Social Science Collection which highlighted 449 citations; from these 14 papers met the review inclusion criteria.

REVIEW METHODS

Both empirical studies and editorials focusing upon widening participation in pre-registration nurse education in the UK (2013-2016) were included. Papers excluded were non UK papers or papers not focussed upon widening participation in pre-registration nursing education. Research papers included in the review were assessed for quality using appropriate critical appraisal tools.

RESULTS

14 papers were included in the review; these were analysed thematically identifying four themes; knowledge and identification of WP, pedagogy and WP, attrition and retention and career prospects.

CONCLUSIONS

Whilst widening participation is a key issue for both nurse education and the wider profession there is a lack of conceptualisation and focus regarding mechanisms to both encourage and support a wider diversity of entrant. Whilst there are some studies, these focus on particular individual widening participation groups rather than a wider strategic focus across the student lifecycle.

Does nurses' vulnerability affect their ability to care?

Recent reports from the Department of Health (2008), the Parliamentary and Health Service Ombudsman (2011) and the Commission on Dignity in Care for Older People (2012) have been highly critical regarding the care that some patients have experienced. They have highlighted that fundamental aspects of care are missing resulting in a lack of high quality individualised nursing care, which is in contrast with holistic nursing philosophy. We have to ask ourselves what is happening within nursing, as many enter the profession owing to a desire to 'make a difference'. Drawing on focus group data exploring perceptions of caring for residents with dementia in a care home setting, the authors found that nurses and healthcare assistants experience a mutual vulnerability with patients. This paper explores whether this mutual vulnerability could lead to nurses focusing on the clinical aspects of their role to the detriment of the compassionate, caring components of nursing.

A brief report on an action learning group exploration of how older people adapt to change in later life

In collaboration with Age Concern UK, older people were invited to participate in action learning groups to explore how they adapt to change. Themes for discussion were initially identified using a nominal focus method. Discussions identified actual and desired methods of coping with changes in later life. A series of weekly meetings with three cohorts of urban, rural and sheltered accommodation participants with an average age of 81 years revealed that they were concerned with having to cope with and adapt to a wide range of experiences. These included the loss of sharing and reduced sociability, reduced mobility, bereavement, physical changes, having to move house and/or location, having to retire, and having to deal with outside agencies. In order to cope with these experiences, participants engaged in a range of activities that centered on aspects of communication and social networking. Participants talked to each other socially and informally, exchanging information and advice. When able, they also participated in more structured but non-specific social events during which time they also had the opportunity to support each other. Participants suggested that there was a role for statutory and nonstatutory bodies and professions such as mental health and community adult nursing, occupational therapy and social work to provide more formal social networking and information exchange opportunities.

A simple drawing test to identify patients who are unlikely to be able to learn to use an inhaler

Previous research has shown that patients are not able to learn to use self-administered inhaler devices if they have impaired general cognition, executive (frontal lobe) dysfunction or dyspraxia. These impairments are most frequently encountered in frail elderly people. Some of the tests required to detect such impairments are time-consuming and are therefore not easily adopted in routine clinical practice, particularly in an outpatient setting. We performed a study of 50 elderly inhaler-naïve patients to explore the use of a simple quick drawing test (copying overlapping pentagons) to determine whether that test was able to identify patients who were unable to learn to use a Turbohaler. Patients who were not able to perform the pentagon copying test were found to be unable to learn to use a Turbohaler with a specificity of 93% and positive predictive value of 87%. This was at least as discriminating as the Abbreviated Mental Test and the Mini Mental State Examination. The overlapping pentagon drawing test is useful in clinical practice to identify patients who will probably not use a self-administered inhaler correctly, and who will require an alternative approach to the treatment of their airways disease. This finding might have implications for other self-administered treatment, such as insulin pens and complex drug regimens.

BRL37344, but not CGP12177, stimulates fuel oxidation by soleus muscle in vitro

The beta(3)-adrenoceptor agonist, (RR+SS)-(+/-)-4-[2-)2-)3-chlorophenyl)-2-hydroxyethyl)amino)propyl]ph enoxyacetate (BRL37344), stimulated fuel utilisation by isolated mouse soleus muscle at concentrations 10- to 100-fold lower than those required to stimulate lipolysis in brown adipocytes. At 1x10(-10) M BRL37344, uptake and phosphorylation of 2-deoxyglucose was increased (40%), as was glucose-oxidation (50%), palmitate-oxidation (70%) and oxidation of [2-14C]pyruvate (2-fold), indicating stimulation of tricarboxylic acid cycle reactions. Oxidation of [1-14C]pyruvate was unaffected, indicating no stimulation of pyruvate dehydrogenase activity. Other beta(3)-adrenoceptor agonists, disodium(RR)-5-[2-[[2-(3-chlorophenyl)-2-hydroxyethyl]-amino]propyl]- 1,3-benzodioxazole-2,2-dicarboxylate (CL316,243, 1x10(-7) M) and (S)-4-¿2-[2-hydroxy-3-(4-hydroxyphenoxy)propylamino]ethyl¿pheno xymeth ylcyclohexylphosphiric acid lithium salt (SB226552, 1x10(-9) M), achieved similar stimulation of 2-deoxyglucose uptake and phosphorylation but (+/-)-4-(3-t-butylamino-2-hydroxypropoxy)benzimidazol-2-one (CGP12177A) had no effect. The inhibitor of protein kinase A, H-89 (isoquinolinesulfonamide), had little effect on the stimulation of pyruvate-oxidation by BRL37344, while the specific inhibitor of protein kinase C, bisindolylmaleimide IX, reduced the stimulated rate to slightly below basal values. We consider that these responses provide evidence of the presence of a novel beta-adrenoceptor in skeletal muscle, which we have termed beta(skel)-adrenoceptor.

N-Acetyl-beta-D-glucopyranosylamine 6-phosphate is a specific inhibitor of glycogen-bound protein phosphatase 1

Previous work has shown that the C-1-substituted glucose-analogue N-acetyl-beta-D-glucopyranosylamine (1-GlcNAc) is a competitive inhibitor of glycogen phosphorylase (GP) and stimulates the inactivation of this enzyme by GP phosphatase. In addition to its effects on GP, 1-GlcNAc also prevents the glucose-led activation of glycogen synthase (GS) in whole hepatocytes. Such an effect on GS was thought to be due to the formation of 1-GlcNAc-6-P by the action of glucokinase within the hepatocyte [Board, Bollen, Stalmans, Kim, Fleet and Johnson (1995) Biochem. J. 311, 845-852]. To investigate this possibility further, a pure preparation of 1-GlcNAc-6-P was synthesized. The effects of the phosphorylated glucose analogue on the activity of protein phosphatase 1 (PP1), the enzyme responsible for dephosphorylation and activation of GS, are reported. During the present study, 1-GlcNAc-6-P inhibited the activity of the glycogen-bound form of PP1, affecting both the GSb phosphatase and GPa phosphatase activities. A level of 50% inhibition of GSb phosphatase activity was achieved with 85 microM 1-GlcNAc-6-P in the absence of Glc-6-P and with 135 microM in the presence of 10 mM Glc-6-P. At either Glc-6-P concentration, 500 microM 1-GlcNAc-6-P completely inhibited activity. The Glc-6-P stimulation of the GPa phosphatase activity of PP1 was negated by 1-GlcNAc-6-P but there was no inhibition of the basal rate in the absence of Glc-6-P. 1-GlcNAc-6-P inhibition was specific for the glycogen-bound form of PP1 and did not inhibit the GSb phosphatase activity of the cytosolic form of the enzyme. The present work explains our previous observations on the inactivating effects on GS of incubating whole hepatocytes with 1-GlcNAc. These observations have their basis in the inhibition of glycogen-bound PP1 by 1-GlcNAc-6-P. A novel inhibitor of PP1, specific for the glycogen-bound form of the enzyme, is presented.

Hydroxycitrate causes altered pyruvate metabolism by tumorigenic cells

Metabolic fates of pyruvate (CO2, lactate, citrate) in normal and neoplastic cells have been assessed. Pyruvate consumption by tumour cells falls (by 72-85%) and mean percentage oxidation rises from 75% to 91% with hydroxycitrate. Ratios of rates of oxidation of (3-(14)C-pyruvate) : (1-(14)C-pyruvate), indicating CO2 produced from TCA cycle activity : that from PDH activity, are higher for tumorigenic (0.17-0.24) than for non-tumorigenic (0.005-0.04) cells and increase (0.27-0.65 and 0.13-0.29, respectively) with hydroxycitrate. Although maximal ATP-citrate lyase activities do not correlate with malignancy, citrate may be a major fate of glutaminolytic pyruvate in tumour cells. Citrate accounts for 14-37% of consumed glutamine compared with 11-13% being recovered as CO2. By contrast, approximately 100% of glycolytic pyruvate is converted to lactate.

Effects of C-1-substituted glucose analogue on the activation states of glycogen synthase and glycogen phosphorylase in rat hepatocytes

A series of glucose-analogue inhibitors of glycogen phosphorylase b (GPb) has been designed, synthesized and investigated in crystallographic binding and kinetic studies. The aim is to produce a compound that may exert more effective control over glycogen metabolism than the parent glucose molecule and which could alleviate hyperglycaemia in Type-II diabetes. N-Acetyl-beta-D-glucopyranosylamine (1-GlcNAc) has a Ki for muscle GPb in crude extracts of 30 microM, 367-fold lower than that of beta-D-glucose [Board, Hadwen and Johnson (1995) Eur. J. Biochem. 228, 753-761]. In the current work, the effects of 1-GlcNAc on the activation states of GP and glycogen synthase (GS) in cell-free preparations and in isolated hepatocytes are reported. In gel-filtered extracts of liver, which lack ATP for kinase activity, 1-GlcNAc produced a rapid and time-dependent inactivation of GP with a subsequent activation of GS. Effects of 1-GlcNAc on both enzymes were stronger than those of glucose, with 0.8 mM 1-GlcNAc being equipotent with 50 mM glucose. At 1 mM, 1-GlcNAc enhanced the dephosphorylation of exogenous GPa by liver extracts (600%) and by muscle extracts (75%). This represents an approximately 500-fold improvement on glucose for the liver activity and 40-fold for the muscle activity. In whole hepatocytes, 1-GlcNAc showed an approximately 5-fold enhancement of glucose effects for GP inactivation but failed to elicit activation of GS. Glucose-induced activation of GS in whole hepatocytes was reversed by subsequent addition of 1-GlcNAc. However, when GS activation was achieved via the adenosine analogue and kinase inhibitor, 5'-iodotubercidin (ITU), subsequent addition of 1-GlcNAc allowed continued activation of GS. Phosphorylation of 1-GlcNAc in rat hepatocytes was established using radiolabelled material. The rate of phosphorylation was 1.60 nmol/min per 10(6) cells at 20 mM 1-GlcNAc but was reduced by the presence of 50 microM ITU (0.775 nmol/min per 10(6) cells). It is suggested that the phosphorylated derivative of 1-GlcNAc formed in hepatocytes is 1-GlcNAc 6-phosphate and that the presence of this species is responsible for the failure of 1-GlcNAc to activate GS. The relative importance of the reduction in concentration of GPa versus increased glucose 6-phosphate levels for activation of GS is discussed.

Comparison of disposable and glass mercury thermometers

The aim of this study was to compare the accuracy of disposable thermometer recordings with those from a mercury thermometer. The disposable thermometer has heat-sensitive clinical dots that change colour to indicate temperature measurement. The trial provided fascinating information, questioning current nursing practice and the safety of the tools we use. We need to challenge when and with what we record patients' temperatures. The results from the trial suggested that not only did the disposable thermometer record quicker than the mercury thermometer but that it was as accurate and cheaper.

High Km glucose-phosphorylating (glucokinase) activities in a range of tumor cell lines and inhibition of rates of tumor growth by the specific enzyme inhibitor mannoheptulose

Differences in modes of control of glycolysis in tumor cells, compared with normal cells, have suggested that phosphofructokinase may not catalyse the rate-controlling step. Instead, hexokinase activity may assume a more important regulatory role. Hexokinase activities are consistently lower than those of phosphofructokinase in tumor cells, and the former enzyme may be saturated with its substrate (M. Board et al., Biochem. J. 265: 503-509, 1990). The present work has focused on the glucose-phosphorylation step in tumor cell glycolysis. A range of eight human tumor cell-lines, one human tumor tissue, and four rat tumor cell lines were found to have an additional glucose-phosphorylating activity, with properties similar to hepatic glucokinase. Maximal activities range from 1.1-20 nmol/min/mg cell protein, and the activity is consistently absent from any untransformed cell line or tissue tested, except rat liver tissue (18 nmol/min/mg cell protein). Tumor cell glucokinase activity has been characterized by its high Km for glucose (8-11.8 mM); inhibition by the specific glucokinase inhibitor, mannoheptulose (I50, 12.5 mM); and lack of inhibition by 10 mM glucose-6-phosphate. Mannoheptulose also causes inhibition of glucose uptake by tumor cells (25-75% at 30 mM mannoheptulose) and inhibition of rates of growth of cultured tumor cell lines (I50, 21.4 mM). Rates of growth of human tumors in experimental animals are dramatically reduced (by 65-79%) by a dose of 1.7 mg/g mannoheptulose daily for 5 days. The potential of the naturally occurring sugar, mannoheptulose (which is purified from avocados and is assumed to be of low toxicity), as a cancer treatment is discussed.

Effects of novel analogues of D-glucose on glycogen phosphorylase activities in crude extracts of liver and skeletal muscle

The inhibitory properties of a series of both N-linked and C-linked C1-substituted glucose derivatives towards glycogen phosphorylase (GP) activity from crude extracts of rat liver and muscle have been measured. The most effective inhibitor was N-acetyl-beta-D-glucopyranosylamine, which has Kis of 51 microM (muscle GPa), 30 microM (muscle GPb), 2.7 mM (liver GPa) and 4 mM (liver GPb). All analogues tested inhibit muscle GP more potently than liver GP, highlighting some differences between the two isoenzymes, which are nearly 80% similar. The human liver GP enzyme has been modelled on the basis of the rabbit muscle structure and, together with comparison of structures of muscle GPa and GPb, has provided some insights into possible explanations for the different properties of the two isoenzymes. Maximal activities of GP have also been measured in tissues from diabetic (db/db) and wild-type (db/+) mice. Liver GP from db/db mice exhibits higher activity [132% (a)-67% (b)] than from db/+ controls, although similar activities were observed for muscle GP from both db/db and db/+ animals.

Application of metabolic-control logic to fuel utilization and its significance in tumor cells

The importance and the value of applying metabolic-control logic to the question of fuels, their rates of utilization and their significance to the process of proliferation are presented. Application of the recently developed quantitative theory of metabolic control of branched pathways provides a hypothesis to account for the high rate of both glycolysis and glutaminolysis in lymphocytes, macrophages and, in particular, in tumor cells. Both glycolysis and glutaminolysis provide metabolic intermediates for biosynthetic pathways: for example, glucose-6-phosphate for the formation of ribose-5-phosphate, and glutamine, ammonia and aspartate which are required for the synthesis of purine and pyrimidine nucleotides. However, the rates of both glycolysis and glutaminolysis are greatly in excess (greater than 400-fold) of the requirements for the biosynthetic processes. If energy formation per se was the major reason for the high rate of glutamine utilization, why is the oxidation only partial? The ability of the cell to divide will require the synthesis of all the DNA, RNA, phospholipids, etc., at precise times in the cell cycle. Hence very high and accurate sensitivity of the processes that provide the precursors for these compounds to their specific regulators will be expected. Maintenance of high rates of glycolysis and glutaminolysis at all times can be seen therefore as a device to allow intermediates to be "tapped off" at the precise rate required whenever they are needed for biosynthesis. Maximal activities of some key enzymes of glycolysis, the tricarboxylic acid cycle and glutaminolysis from a variety of normal, neoplastic and suppressed cells are presented. The relative activities of hexokinase and 6-phosphofructokinase suggest that, particularly in neoplastic cells, in which the capacity for glucose transport is high, hexokinase could approach saturation in respect to intracellular glucose; consequently, hexokinase and phosphofructokinase could play an important role in the regulation of glycolytic flux in these cells. The activity of pyruvate kinase is considerably higher in tumorigenic cells than in nontumorigenic cells and higher in metastatic cells than in tumorigenic cells: for nontumorigenic cells the activities range from 28.4 to 574, for tumorigenic cells from 899 to 1280, and for metastatic cells from 1590 to 1627 nmol/min per mg of protein. The ratio of pyruvate kinase activity to 2 x phosphofructokinase activity is very high in neoplastic cells. The mean is 22.4 for neoplastic cells, whereas for muscle from 60 different animals it is only 3.8.(ABSTRACT TRUNCATED AT 400 WORDS)

Maximum activities of key enzymes of glycolysis, glutaminolysis, pentose phosphate pathway and tricarboxylic acid cycle in normal, neoplastic and suppressed cells

1. Maximal activities of some key enzymes of glycolysis, the pentose phosphate pathway, the tricarboxylic acid cycle and glutaminolysis were measured in homogenates from a variety of normal, neoplastic and suppressed cells. 2. The relative activities of hexokinase and 6-phosphofructokinase suggest that, particularly in neoplastic cells, in which the capacity for glucose transport is high, hexokinase could approach saturation in respect to intracellular glucose; consequently, hexokinase and phosphofructokinase could play an important role in the regulation of glycolytic flux in these cells. 3. The activity of pyruvate kinase is considerably higher in tumorigenic cells than in non-tumorigenic cells and higher in metastatic cells than in tumorigenic cells: for non-tumorigenic cells the activities range from 28.4 to 574, for tumorigenic cells from 899 to 1280, and for metastatic cells from 1590 to 1627 nmol/min per mg of protein. 4. The ratio of pyruvate kinase activity to 2 x phosphofructokinase activity is very high in neoplastic cells. The mean is 22.4 for neoplastic cells, whereas for muscle from 60 different animals it is only 3.8. 5. Both citrate synthase and isocitrate dehydrogenase activities are present in non-neoplastic and neoplastic cells, suggesting that the full complement of tricarboxylic-acid-cycle enzymes are present in these latter cells. 6. In neoplastic cells, the activity of glutaminase is similar to or greater than that of hexokinase, which suggests that glutamine may be as important as glucose for energy generation in these cells.