Dementia Early-Stage Cognitive Aids New Trial (DESCANT) of memory aids and guidance for people with dementia: randomised controlled trial

BACKGROUND

Common memory aids for people with dementia at home are recommended. However, rigorous evaluation is lacking, particularly what guidance or support is valued.

OBJECTIVE

To investigate effects of memory aids and guidance by dementia support practitioners (DSPs) for people in early-stage dementia through a pragmatic, randomised controlled trial.

METHODS

Of 469 people with mild-to-moderate dementia and their informal carers, 468 were randomised to a DSP with memory aids or to usual care plus existing dementia guide. Allocation was stratified by Trust/Health Board; time since first attendance at memory service; gender; age; and living with primary carer or not. Primary outcome was Bristol Activities of Daily Living Scale (BADLS) Score at 3 and 6 months (primary end-point). Secondary outcomes for people with dementia: quality of life (CASP-19; DEMQOL); cognition and functioning (Clinical Dementia Rating Scale; S-MMSE); capability (ICECAP-O); social networks (LSNS-R); and instrumental daily living activities (R-IDDD). Secondary outcomes for carers: psychological health (GHQ-12); sense of competence (SSCQ).

RESULTS

DSPs were successfully trained, compliance was good and welcomed by participants. Mean 6 months BADLS Score increased to 14.6 (SD: 10.4) in intervention and 12.6 (SD: 8.1) in comparator, indicative of greater dependence in the activities of daily living. Adjusted between-group difference was 0.38 (95% CI: -0.89 to 1.65, p=0.56). Though this suggests greater dependency in the intervention group the difference was not significant. No differences were found in secondary outcomes.

CONCLUSIONS

This intervention did not maintain independence in the activities of daily living with no improvement in other outcomes for people with dementia or carers.

TRIAL REGISTRATION NUMBER

Current Controlled Trials ISRCTN12591717.

Evaluation of prognostic risk models for postoperative pulmonary complications in adult patients undergoing major abdominal surgery: a systematic review and international external validation cohort study

BACKGROUND

Stratifying risk of postoperative pulmonary complications after major abdominal surgery allows clinicians to modify risk through targeted interventions and enhanced monitoring. In this study, we aimed to identify and validate prognostic models against a new consensus definition of postoperative pulmonary complications.

METHODS

We did a systematic review and international external validation cohort study. The systematic review was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched MEDLINE and Embase on March 1, 2020, for articles published in English that reported on risk prediction models for postoperative pulmonary complications following abdominal surgery. External validation of existing models was done within a prospective international cohort study of adult patients (≥18 years) undergoing major abdominal surgery. Data were collected between Jan 1, 2019, and April 30, 2019, in the UK, Ireland, and Australia. Discriminative ability and prognostic accuracy summary statistics were compared between models for the 30-day postoperative pulmonary complication rate as defined by the Standardised Endpoints in Perioperative Medicine Core Outcome Measures in Perioperative and Anaesthetic Care (StEP-COMPAC). Model performance was compared using the area under the receiver operating characteristic curve (AUROCC).

FINDINGS

In total, we identified 2903 records from our literature search; of which, 2514 (86·6%) unique records were screened, 121 (4·8%) of 2514 full texts were assessed for eligibility, and 29 unique prognostic models were identified. Nine (31·0%) of 29 models had score development reported only, 19 (65·5%) had undergone internal validation, and only four (13·8%) had been externally validated. Data to validate six eligible models were collected in the international external validation cohort study. Data from 11 591 patients were available, with an overall postoperative pulmonary complication rate of 7·8% (n=903). None of the six models showed good discrimination (defined as AUROCC ≥0·70) for identifying postoperative pulmonary complications, with the Assess Respiratory Risk in Surgical Patients in Catalonia score showing the best discrimination (AUROCC 0·700 [95% CI 0·683-0·717]).

INTERPRETATION

In the pre-COVID-19 pandemic data, variability in the risk of pulmonary complications (StEP-COMPAC definition) following major abdominal surgery was poorly described by existing prognostication tools. To improve surgical safety during the COVID-19 pandemic recovery and beyond, novel risk stratification tools are required.

FUNDING

British Journal of Surgery Society.

Racial disparities in the use of mechanical circulatory support devices in cardiogenic shock

Background

Racial bias has always been a concern for healthcare. Lack of guideline directed utilization of mechanical circulatory support (MCS) devices in cardiogenic shock (CS) may lead to implicit and racial bias.

Purpose

To identify the racial differences in the use of mechanical circulatory support in cardiogenic shock and its association with outcomes.

Methods

National Inpatient Database from 2015–2018 using ICD 10 codes was used. Patients >18 years of age admitted for cariogenic shock were included.

Results

Among 1,021,274 patients hospitalized for cardiogenic shock, overall MCS was utilized in 11.4% (N=116,539). Use of MCS for patients stratified by race was 12.2% white (N=85543), 8% Blacks (N=14688), 11.3% Hispanics (N=11067), 13.8% Asian (N=4417), 12.3% Native American (N=825). IABP was the most commonly used MCS device, followed by Impella, ECMO and LVAD. Overall odds of MCS insertion was significantly higher in white population [1.18 (1.13–1.23) <0.001] and significantly lower in Blacks [0.65 (0.61–0.69) <0.001] and Hispanics [0.89 (0.83–0.97) 0.004]. Among black patients with CS requiring MCS, odds of LVAD insertion were similar compared to other races [1.03 (0.89–1.19) 0.714], while odds of all other types of MCS devices including ECMO [0.83 (0.72–0.95) 0.009], IABP [0.63 (0.59–0.68) <0.001] and Impella [0.61 (0.54–0.70) <0.001] were significantly lower compared to other races. This trend also holds true for patients with CS associated with acute myocardial infarction. Among all patients with CS, the odds of mortality were significantly lower among white patients [0.92 (0.90–0.95) <0.001], on the contrary, odds of mortality were significantly higher in Blacks [1.06 (1.02–1.10) 0.001] and Asians [1.11 (1.02–1.20) 0.012]. Interestingly, when only comparing patients who underwent MCS utilization for CS, odds of mortality were similar in black population compared to other races. [1.03 (0.91–1.17) 0.636].

Conclusion(s)

There still exist significant racial differences in the use of mechanical circulatory devices for cardiogenic shock potentially leading to significantly higher mortality in black population compared to whites. This difference in mortality is mitigated with equal use of MCS devices in cardiogenic shock among all races.

Funding Acknowledgement

Type of funding sources: None.

Components, impacts and costs of dementia home support: a research programme including the DESCANT RCT

Background

Over half of people with dementia live at home. We know little about what home support could be clinically effective or cost-effective in enabling them to live well.

Objectives

We aimed to (1) review evidence for components of home support, identify their presence in the literature and in services in England, and develop an appropriate economic model; (2) develop and test a practical memory support package in early-stage dementia, test the clinical effectiveness and cost-effectiveness of routine home support in later-stage dementia and design a toolkit based on this evidence; and (3) elicit the preferences of staff, carers and people with dementia for home support inputs and packages, and evaluate the cost-effectiveness of these approaches in early- and later-stage dementia.

Design

We undertook (1) an evidence synthesis, national surveys on the NHS and social care and an economic review; (2) a multicentre pragmatic randomised trial [Dementia Early Stage Cognitive Aids New Trial (DESCANT)] to estimate the clinical effectiveness and cost-effectiveness of providing memory aids and guidance to people with early-stage dementia (the DESCANT intervention), alongside process evaluation and qualitative analysis, an observational study of existing care packages in later-stage dementia along with qualitative analysis, and toolkit development to summarise this evidence; and (3) consultation with experts, staff and carers to explore the balance between informal and paid home support using case vignettes, discrete choice experiments to explore the preferences of people with dementia and carers between home support packages in early- and later-stage dementia, and cost–utility analysis building on trial and observational study.

Setting

The national surveys described Community Mental Health Teams, memory clinics and social care services across England. Recruitment to the trial was through memory services in nine NHS trusts in England and one health board in Wales. Recruitment to the observational study was through social services in 17 local authorities in England. Recruitment for the vignette and preference studies was through memory services, community centres and carers’ organisations.

Participants

People aged > 50 years with dementia within 1 year of first attendance at a memory clinic were eligible for the trial. People aged > 60 years with later-stage dementia within 3 months of a review of care needs were eligible for the observational study. We recruited staff, carers and people with dementia for the vignette and preference studies. All participants had to give written informed consent.

Main outcome measures

The trial and observational study used the Bristol Activities of Daily Living Scale as the primary outcome and also measured quality of life, capability, cognition, general psychological health and carers’ sense of competence.

Methods

Owing to the heterogeneity of interventions, methods and outcome measures, our evidence and economic reviews both used narrative synthesis. The main source of economic studies was the NHS Economic Evaluation Database. We analysed the trial and observational study by linear mixed models. We analysed the trial by ‘treatment allocated’ and used propensity scores to minimise confounding in the observational study.

Results

Our reviews and surveys identified several home support approaches of potential benefit. In early-stage dementia, the DESCANT trial had 468 randomised participants (234 intervention participants and 234 control participants), with 347 participants analysed. We found no significant effect at the primary end point of 6 months of the DESCANT intervention on any of several participant outcome measures. The primary outcome was the Bristol Activities of Daily Living Scale, for which scores range from 0 to 60, with higher scores showing greater dependence. After adjustment for differences at baseline, the mean difference was 0.38, slightly but not significantly favouring the comparator group receiving treatment as usual. The 95% confidence interval ran from –0.89 to 1.65 (p = 0.56). There was no evidence that more intensive care packages in later-stage dementia were more effective than basic care. However, formal home care appeared to help keep people at home. Staff recommended informal care that cost 88% of formal care, but for informal carers this ratio was only 62%. People with dementia preferred social and recreational activities, and carers preferred respite care and regular home care. The DESCANT intervention is probably not cost-effective in early-stage dementia, and intensive care packages are probably not cost-effective in later-stage dementia. From the perspective of the third sector, intermediate intensity packages were cheaper but less effective. Certain elements may be driving these results, notably reduced use of carers’ groups.

Limitations

Our chosen outcome measures may not reflect subtle outcomes valued by people with dementia.

Conclusions

Several approaches preferred by people with dementia and their carers have potential. However, memory aids aiming to affect daily living activities in early-stage dementia or intensive packages compared with basic care in later-stage dementia were not clinically effective or cost-effective.

Future work

Further work needs to identify what people with dementia and their carers prefer and develop more sensitive outcome measures.

Study registration

Current Controlled Trials ISRCTN12591717. The evidence synthesis is registered as PROSPERO CRD42014008890.

Funding

This project was funded by the National Institute for Health Research (NIHR) Programme Grants for Applied Research programme and will be published in full in Programme Grants for Applied Research; Vol. 9, No. 6. See the NIHR Journals Library website for further project information.

Complex care needs and devolution in Greater Manchester: a pilot study to explore social care innovation in newly integrated service arrangements for older people

Objective The aim of this study was to describe emergent approaches to integrated care for older people with complex care needs and investigate the viability of measuring integrated care. Methods A case study approach was used. Sites were recruited following discussion with senior staff in health and social care agencies. Service arrangements were categorised using a framework developed by the researchers. To investigate joint working within the sites, the development model for integrated care was adapted and administered to the manager of each service. Data were collected in 2018. Results Six case study sites were recruited illustrating adult social care services partnerships in services for older people with home care providers, mental health and community nursing services. Most were established in 2018. Service arrangements were characterised by joint assessment and informal face-to-face discussions between staff. The development of an infrastructure to promote partnership working was evident between adult social care and each of the other services and most developed with home care providers. There was little evidence of a sequential approach to the development of integrated working practices. Conclusion Components of partnerships promoting integrated care have been highlighted and understanding of the complexity of measuring integrated care enhanced. Means of information sharing and work force development require further consideration. What is known about the topic? The devolution of health and social care arrangements in Greater Manchester has aroused considerable interest in much wider arenas. Necessarily much of the focus in available material has been upon strategic development, analysis of broader trends and mechanisms and a concern with changes in the healthcare system. What does this paper add? The findings from this study will enable emerging approaches to be described and codified, and permit the specific social care contribution to the new arrangements to be discerned. The findings are relevant beyond the immediate context of Greater Manchester to wider integrated care. The evidence can be used by commissioners and services, providing a sound basis for further work as service systems develop. What are the implications for practitioners? This research is important because it is one of the first pieces of work to examine the new integrated care arrangements in Greater Manchester. By providing guidance to promote evidence-based practice, this study contributes to service development in Greater Manchester and the achievement of the broad national service objectives of improving user and carer experiences and ensuring value for money.

Dementia and mild cognitive impairment in prisoners aged over 50 years in England and Wales: a mixed-methods study

Background

People aged ≥ 50 years constitute the fastest-growing group in the prison population of England and Wales. This population has complex health and social care needs. There is currently no national strategy to guide the development of the many-faceted services required for this vulnerable population; therefore, prisons are responding to the issue with a range of local initiatives that are untested and often susceptible to failure if they are not fully embedded in and securely funded as part of commissioned services.

Objectives

The objectives were to establish the prevalence of dementia and mild cognitive impairment in prisoners in England and Wales and their health and social care needs; validate the six-item cognitive impairment test for routine use in prisons to aid early and consistent identification of older prisoners with possible dementia or mild cognitive impairment; identify gaps in current service provision; understand the first-hand experiences of prisoners living with dementia and mild cognitive impairment; develop a care pathway for prisoners with dementia and mild cognitive impairment; develop dementia and mild cognitive impairment training packages for staff and prisoners; and produce health economic costings for the care pathway and training packages.

Design

This was a mixed-methods study.

Setting

The study setting was prisons in England and Wales.

Participants

Prisoners aged ≥ 50 years and multiagency staff working in prison discipline and health and social care services took part.

Results

Quantitative research estimated that the prevalence rate of suspected dementia and mild cognitive impairment in the prison population of England and Wales is 8%. This equates to 1090 individuals. Only two people (3%) in our sample had a relevant diagnosis in their health-care notes, suggesting current under-recognition of these conditions. The prevalence rate in prisons was approximately two times higher among individuals aged 60–69 years and four times higher among those aged ≥ 70 years than among those in the same age groups living in the community. The Montreal Cognitive Assessment screening test was found to be more effective than the six-item cognitive impairment test assessment in the older prisoner population. Qualitative research determined that staff and prisoners lacked training in knowledge and awareness of dementia and mild cognitive impairment, and this leads to problematic behaviour being viewed as a disciplinary issue rather than a health issue. Local initiatives to improve the lives of prisoners with dementia and mild cognitive impairment are often disadvantaged by not being part of commissioned services, making them difficult to sustain. Multidisciplinary working is hampered by agencies continuing to work in silos, with inadequate communication across professional boundaries. A step-by-step care pathway for prisoners with dementia and mild cognitive impairment was developed, and two tiers of training materials were produced for staff and prisoners.

Limitations

Our prevalence rate was based on the results of a standardised assessment tool, rather than on clinical diagnosis by a mental health professional, and therefore it may represent an overestimation. Furthermore, we were unable to distinguish subcategories of dementia. We were also unable to distinguish between a likely diagnosis of dementia and other conditions presenting with mild cognitive impairment, including learning disability, severe depression and hearing impairment. Questionnaires regarding current service provision were collected over an extended period of time, so they do not reflect a ‘snapshot’ of service provision at a particular point.

Conclusions

We hypothesise that implementing the step-by-step care pathway and the training resources developed in this study will improve the care of older prisoners with dementia and mild cognitive impairment.

Future work

The care pathway and training materials should be evaluated in situ. Alternatives to prison for those with dementia or mild cognitive impairment should be developed and evaluated.

Funding

This project was funded by the National Institute for Health Research (NIHR) Health Services and Delivery Research programme and will be published in full in Health Services and Delivery Research; Vol. 8, No. 27. See the NIHR Journals Library website for further project information.

Evaluating the effectiveness and cost-effectiveness of Dementia Care Mapping™ to enable person-centred care for people with dementia and their carers (DCM-EPIC) in care homes: study protocol for a randomised controlled trial

BACKGROUND

Up to 90 % of people living with dementia in care homes experience one or more behaviours that staff may describe as challenging to support (BSC). Of these agitation is the most common and difficult to manage. The presence of agitation is associated with fewer visits from relatives, poorer quality of life and social isolation. It is recommended that agitation is treated through psychosocial interventions. Dementia Care Mapping™ (DCM™) is an established, widely used observational tool and practice development cycle, for ensuring a systematic approach to providing person-centred care. There is a body of practice-based literature and experience to suggests that DCM™ is potentially effective but limited robust evidence for its effectiveness, and no examination of its cost-effectiveness, as a UK health care intervention. Therefore, a definitive randomised controlled trial (RCT) of DCM™ in the UK is urgently needed.

METHODS/DESIGN

A pragmatic, multi-centre, cluster-randomised controlled trial of Dementia Care Mapping (DCM™) plus Usual Care (UC) versus UC alone, where UC is the normal care delivered within the care home following a minimum level of dementia awareness training. The trial will take place in residential, nursing and dementia-specialist care homes across West Yorkshire, Oxfordshire and London, with residents with dementia. A random sample of 50 care homes will be selected within which a minimum of 750 residents will be registered. Care homes will be randomised in an allocation ratio of 3:2 to receive either intervention or control. Outcome measures will be obtained at 6 and 16 months following randomisation. The primary outcome is agitation as measured by the Cohen-Mansfield Agitation Inventory, at 16 months post randomisation. Key secondary outcomes are other BSC and quality of life. There will be an integral cost-effectiveness analysis and a process evaluation.

DISCUSSION

The protocol was refined following a pilot of trial procedures. Changes include replacement of a questionnaire, whose wording caused some residents distress, to an adapted version specifically designed for use in care homes, a change to the randomisation stratification factors, adaption in how the staff measures are collected to encourage greater compliance, and additional reminders to intervention homes of when mapping cycles are due, via text message.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN82288852 . Registered on 16 January 2014. Full protocol version and date: v7.1: 18 December 2015.

Orbital dermatofibrosarcoma protuberans with intracranial extension preceded by recurrent leiomyoma of the orbit: a case report

INTRODUCTION

Dermatofibrosarcoma protuberans is a rare, locally aggressive cutaneous tumor of intermediate to low-grade malignancy. COL1A1-PDGFβ translocation is specific to dermatofibrosarcoma protuberans, where the abnormally fused COL1A1-PDGFβ gene directs formation of an abnormal combined (fusion) protein that researchers believe to ultimately function like the platelet-derived growth factor-beta protein.

CASE PRESENTATION

In this report, we present a case of a 63-year-old Asian man with dermatofibrosarcoma protuberans of the right orbit with intracranial extension. He had a prior history of recurrent leiomyomas at the identical site. He underwent near-total en bloc resection of the tumor through a wide craniectomy with a 6 cm rim of the frontal scalp, allowing the tumor to be resected en bloc, leaving negative margins. Microscopically, the tumor comprised spindle cells with mild nuclear atypia and a low mitotic index embedded in a spiraling pattern of decussating fascicles consistent with dermatofibrosarcoma protuberans. The lesion was positive for CD34 and BCL2. Following resection, the patient was started on imatinib mesylate therapy (800 mg/day).

CONCLUSIONS

We propose that platelet-derived growth factor, which has been implicated in the progression of leiomyomas by augmenting mitogenesis, may have acted in an autocrine manner to cause cell division, which may have led to the development of dermatofibrosarcoma protuberans in our patient. Further research is imperative to find certain molecular associations between the discussed soft tissue tumors. Also important is the effective utilization of platelet-derived growth factor receptor kinase inhibitors to prevent transformation to any platelet-derived growth factor-driven tumor, which in our patient was a dermatofibrosarcoma protuberans.

Quantitative pedigree analysis and mitochondrial DNA sequence variants in adults with cyclic vomiting syndrome

Background

Children with cyclic vomiting syndrome (CVS) have a high degree of maternal inheritance of functional gastrointestinal and neurological disorders. CVS in children is also associated with an increased prevalence of mitochondrial DNA single-nucleotide polymorphisms (mtDNA SNPs) 16519 T and 3010A. Preliminary data suggests that age of onset of symptoms (pediatric vs. adult) may be a determinant of the presence of such mtDNA SNP’s. We sought to examine the degree of maternal inheritance pattern of functional disorders and the prevalence of mtDNA SNP’s16519T and 3010A in adults with CVS and correlate this with age of onset of disease.

Methods

A Quantitative Pedigree Analysis (QPA) was performed in 195 of a total of 216 patients and all were genotyped using Restriction Fragment Length Polymorphism (RFLP) or sequencing.

Results

Adults with CVS had a higher degree of probable maternal inheritance (PMI) of functional disorders than controls (12% vs. 1%, p < 0.001). However, the prevalence of mitochondrial SNP’s 16519 T, 3010A and the AT genotype were similar in Haplogroup H CVS patients compared to historical controls. There was no correlation between age of onset of disease and prevalence of these mtDNA SNP’s.

Conclusions

A subset of adults with CVS has a significantly higher degree of maternal inheritance pattern of functional disorders than controls. There was no association with mtDNA SNP’s 16519 T and 3010A as seen in children and future studies sequencing the entire mitochondrial and nuclear genome to identify potential causes for this maternal inheritance pattern in adults are warranted.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-230X-14-181) contains supplementary material, which is available to authorized users.

Escherichia coli signal peptidase recognizes and cleaves the signal sequence of α-amylase originating from Bacillus licheniformis

The gene encoding the α-amylase from Bacillus licheniformis was cloned, with and without the native signal sequence, and expressed in Escherichia coli, resulting in the production of the recombinant protein in the cytoplasm as insoluble but enzymatically active aggregates. Expression with a low concentration of the inducer at low temperature resulted in the production of the recombinant protein in soluble form in a significantly higher amount. The protein produced with signal sequence was exported to the extracellular medium, whereas there was no export of the protein produced from the gene without the signal sequence. Similarly, the α-amylase activity in the culture medium increased with time after induction in case of the protein produced with signal sequence. Molecular mass determinations by MALDI-TOF mass spectrometry and N-terminal amino acid sequencing of the purified recombinant α-amylase from the extracellular medium revealed that the native signal peptide was cleaved by E. coli signal peptidase between Ala28 and Ala29. It seems possible that the signal peptide of α-amylase from B. licheniformis can be used for the secretion of other recombinant proteins produced using the E. coli expression system.

Tele-healthcare for diabetes management: A low cost automatic approach

In this paper, a telemedicine system for managing diabetic patients with better care is presented. The system is an end to end solution which relies on the integration of front end (patient unit) and backend web server. A key feature of the system developed is the very low cost automated approach. The front-end of the system is capable of reading glucose measurements from any glucose meter and sending them automatically via existing networks to the back-end server. The back-end is designed and developed using n-tier web client architecture based on model-view-controller design pattern using open source technology, a cost effective solution. The back-end helps the health-care provider with data analysis; data visualization and decision support, and allows them to send feedback and therapeutic advice to patients from anywhere using a browser enabled device. This system will be evaluated during the trials which will be conducted in collaboration with a local hospital in phased manner.

Invasive candidiasis in Pakistan: clinical characteristics, species distribution and antifungal susceptibility

This study reports for the first time, to our knowledge, descriptive epidemiological data for 188 invasive Candida isolates from Pakistan, including species identification and antifungal susceptibility against fluconazole, itraconazole, voriconazole, caspofungin, micafungin, anidulafungin and amphotericin. Risk factors for invasive candidiasis (IC) were determined for 96 patients from Karachi, Pakistan. In adults and neonates, Candida tropicalis (38 and 36 %, respectively) was the most common species, followed in adults by Candida parapsilosis (17.8 %), Candida glabrata (15.9 %) and Candida albicans (12.3 %). C. albicans (21 %) was the second most common in neonates. In children, C. albicans (31.9 %), C. tropicalis (26.4 %) and C. parapsilosis (19.4 %) were the most common. C. albicans IC was significantly associated with paediatric age [crude odds ratio (COR) 3.46, 95 % confidence interval (CI) 1.63-7.32]. Rare species made up 17.5 % of the total isolates studied. Resistance to fluconazole was seen in C. glabrata (15 .0%) and Candida krusei (100 .0%). Only one isolate (C. glabrata) was resistant to all three echinocandins. Low MICs of fluconazole for 98 % (184/188) of isolates tested support its continued use as an empiric therapy for IC. Non-C. albicans IC was associated with the use of β-lactam inhibitor combinations (COR 3.16, 95 % CI 1.05-9.57). Use of healthcare devices was documented in 85.4 % of IC patients, whilst 75 .0% had been admitted to special care units. Surprisingly, 66.7 % of patients with IC were not obviously immunosuppressed. The high frequency of modifiable risk factors in this population indicates that candidaemia can be reduced with stringent antibiotic and infection control measures. These data will be useful for empiric selection of antifungals in Karachi, and contribute to global assessments of antifungal resistance.

Regulation of epithelial sodium channels by the ubiquitin-proteasome proteolytic pathway

Amiloride-sensitive epithelial Na+channels (ENaC) play a crucial role in Na+transport and fluid reabsorption in the kidney, lung, and colon. The magnitude of ENaC-mediated Na+transport in epithelial cells depends on the average open probability of the channels and the number of channels on the apical surface of epithelial cells. The number of channels in the apical membrane, in turn, depends on a balance between the rate of ENaC insertion and the rate of removal from the apical membrane. ENaC is made up of three homologous subunits: α, β, and γ. The COOH-terminal domain of all three subunits is intracellular and contains a proline-rich motif (PPxY). Mutations or deletion of this PPxY motif in the β- and γ-subunits prevent the binding of one isoform of a specific ubiquitin ligase, neural precursor cell-expressed, developmentally downregulated protein (Nedd4–2), to the channel in vitro and in transfected cell systems, thereby impeding ubiquitin conjugation of the channel subunits. Ubiquitin conjugation would seem to imply that ENaC turnover is determined by the ubiquitin-proteasome system, but when Madin-Darby canine kidney cells are transfected with ENaC, ubiquitin conjugation apparently leads to lysosomal degradation. However, in untransfected renal cells (A6) expressing endogenous ENaC, ENaC is indeed degraded by the ubiquitin-proteasome system. Nonetheless, in both transfected and untransfected cells, the rate of ENaC degradation is apparently controlled by Nedd4–2 activity. In this review, we discuss the role of the ubiquitin conjugation and the alternative degradative pathways (lysosomal or proteasomal) in regulating the rate of ENaC turnover in untransfected renal cells and compare this regulation to that of transfected cell systems.

Role of Nedd4-2 and polyubiquitination in epithelial sodium channel degradation in untransfected renal A6 cells expressing endogenous ENaC subunits

Amiloride-sensitive epithelial sodium channels (ENaC) are responsible for transepithelial Na(+) transport in the kidney, lung, and colon. The channel consists of three subunits (alpha, beta, and gamma). In Madin-Darby canine kidney (MDCK) cells and Xenopus laevis oocytes transfected with all three ENaC subunits, neural precursor cell-expressed developmentally downregulated protein (Nedd4-2) promotes ubiquitin conjugation of ENaC. For native proteins in some cells, ubiquitin conjugation is a signal for their degradation by the ubiquitin-proteasome pathway, whereas in other cell types ubiquitin conjugation is a signal for endocytosis and lysosomal protein degradation. When ENaC are transfected into MDCK cells, ubiquitin conjugation leads to lysosomal degradation. In this paper, we characterize the involvement of the ubiquitin-proteasome proteolytic pathway in the regulation of functional ENaC in untransfected renal A6 cells expressing native ENaC subunits. In contrast to transfected cells, we show that total cellular alpha-, beta-, and gamma-ENaC subunits are polyubiquitinated and that ubiquitin conjugation of subunits increases when the cells are treated with a proteasome inhibitor. We show that Nedd4-2 is associated with alpha- and beta-subunits and is associated with the apical membrane. We also show the Nedd4-2 can regulate the number of functional ENaC subunits in the apical membrane. The results reported here suggest that the ubiquitin-proteasome proteolytic pathway is an important determinant of ENaC function in untransfected renal cells expressing endogenous ENaC.

Phosphatase inhibitors increase the open probability of ENaC in A6 cells

We studied the cellular phosphatase inhibitors okadaic acid (OKA), calyculin A, and microcystin on the epithelial sodium channel (ENaC) in A6 renal cells. OKA increased the amiloride-sensitive current after approximately 30 min with maximal stimulation at 1-2 h. Fluctuation analysis of cell-attached patches containing a large number of ENaC yielded power spectra with corner frequencies in untreated cells almost two times as large as in cells pretreated for 30 min with OKA, implying an increase in single channel open probability (P(o)) that doubled after OKA. Single channel analysis showed that, in cells pretreated with OKA, P(o) and mean open time approximately doubled. Two other phosphatase inhibitors, calyculin A and microcystin, had similar effects on P(o) and mean open time. An analog of OKA, okadaone, that does not inhibit phosphatases had no effect. Pretreatment with 10 nM OKA, which blocks protein phosphatase 2A (PP2A) but not PP1 in mammalian cells, had no effect even though both phosphatases are present in A6 cells. Several proteins were differentially phosphorylated after OKA, but ENaC subunit phosphorylation did not increase. We conclude that, in A6 cells, there is an OKA-sensitive phosphatase that suppresses ENaC activity by altering the phosphorylation of a regulatory molecule associated with the channel.

Mechanisms of aldosterone's action on epithelial Na + transport

Aldosterone maintains total organism sodium balance in all higher vertebrates. The level of sodium reabsorption is primarily determined by the action of aldosterone on epithelial sodium channels (ENaC) in the distal nephron. Recent work shows that, in an aldosterone-sensitive renal cell line (A6), aldosterone regulates sodium reabsorption by short- and long-term processes. In the short term, aldosterone regulates sodium transport by inducing expression of the small G-protein, K-Ras2A, by stimulating the activity of methyl transferase and S-adenosyl-homocysteine hydrolase to activate Ras by methylation, and, possibly, by subsequent activation by K-Ras2A of phosphatidylinositol phosphate-5-kinase (PIP-5-K) and phosphatidylinositol-3-kinase (PI-3-K), which ultimately activates ENaC. In the long term, aldosterone regulates sodium transport by altering trafficking, assembly, and degradation of ENaC.

Enac degradation in A6 cells by the ubiquitin-proteosome proteolytic pathway

Amiloride-sensitive epithelial Na(+) channels (ENaC) are responsible for trans-epithelial Na(+) transport in the kidney, lung, and colon. The channel consists of three subunits (alpha, beta, gamma) each containing a proline rich region (PPXY) in their carboxyl-terminal end. Mutations in this PPXY domain cause Liddle's syndrome, an autosomal dominant, salt-sensitive hypertension, by preventing the channel's interactions with the ubiquitin ligase Neural precursor cell-expressed developmentally down-regulated protein (Nedd4). It is postulated that this results in defective endocytosis and lysosomal degradation of ENaC leading to an increase in ENaC activity. To show the pathway that degrades ENaC in epithelial cells that express functioning ENaC channels, we used inhibitors of the proteosome and measured sodium channel activity. We found that the inhibitor, MG-132, increases amiloride-sensitive trans-epithelial current in Xenopus distal nephron A6 cells. There also is an increase of total cellular as well as membrane-associated ENaC subunit molecules by Western blotting. MG-132-treated cells also have increased channel density in patch clamp experiments. Inhibitors of lysosomal function did not reproduce these findings. Our results suggest that in native renal cells the proteosomal pathway is an important regulator of ENaC function.

Effect of titanium exposure on embryonic development during pre-implantation period in rats

Doses of titanium trichloride (1/10th and 1/5th of LD50) were administered once and daily to pregnant rats to assess their effect on embryonic development. 1/5th dose of TiCl3 administered once orally on 1st, 2nd and 3rd day post-coitum. Similarly 1/10th of LD50 was administered daily. Results revealed that 1/10th LD50 dose of TiCl3 was more effective during pre-implantation period as number of 4 and 8-celled embryos decreased as compared to 1/5th. Delayed hatching of the blastocysts on day 5 was registered in TiCl3 treated dam.

[Concentration of cysteine proteinase inhibitors in urine, amniotic fluid and serum from women in pregnancy complicated by EPH-gestosis]

Cysteine proteinase inhibitors (IPC) concentration was measured by the modified Barrett method using papaine in urine, amniotic fluid and serum obtained from the healthy labored women and from labored women in pregnancy complicated by EPH-gestosis. It was noticed the statistically significant increase in the IPC concentration in the material from the pregnant women with EPH-gestosis comparing to the women, which pregnancy had the physiologically normal course.

Differential effects of protein kinase C on the levels of epithelial Na+ channel subunit proteins

Regulation of epithelial Na(+) channel (ENaC) subunit levels by protein kinase C (PKC) was investigated in A6 cells. PKC activation altered ENaC subunit levels, differentially decreasing the levels of both beta and gamma, but not alphaENaC. Temporal regulation of beta and gammaENaC by PKC differed; gammaENaC decreased with a time constant of 3.7 +/- 1.0 h, whereas betaENaC decreased in 13.9 +/- 3. 0 h. Activation of PKC also resulted in a decrease in trans-epithelial Na(+) reabsorption for up to 48 h. PMA activation of PKC resulted in negative feedback inhibition of PKC protein levels beginning within 4 h. Both beta and gammaENaC levels, as well as transport tended toward pretreatment values after 48 h of PMA treatment. PKC inhibitors attenuated the effects of PMA on ENaC subunit levels and Na(+) transport. These results directly show for the first time that PKC differentially regulates ENaC subunit levels by decreasing the levels of beta and gamma but not alphaENaC protein. These results imply a PKC-dependent, long term decrease in Na(+) reabsorption.

Selection of peptidic mimics of digoxin from phage-displayed peptide libraries by anti-digoxin antibodies

Since the initial report of the development of methodology to generate high-affinity digitalis-specific (digoxin) antibodies, these antibodies have proven extremely useful tools to monitor digoxin levels in digitalized patients and, as Fab fragments, to reverse toxic digoxin effects in life-threatening digoxin overdoses. These antibodies (both digoxin-specific and ouabain-specific) have been used extensively by investigators for the identification and characterization of putative endogenous digitalis-like factors. In this study, we used two well-characterized mouse anti-digoxin monoclonal antibodies (mAbs), designated 26-10 and 45-20, as binding templates with which to select short bacteriophage-displayed (pIII protein inserted) peptides that are capable of binding to these mAbs and mimicking the conformational structure of digoxin. Selective enrichment from two phage-displayed random peptide libraries enabled us to isolate and identify distinct 15 and 26 amino acid residue peptide inserts that bind with high avidity and idiotypic specificity to the selecting mAbs. Among these displayed inserts a subset was identified whose mAb binding is inhibited by digoxin and whose corresponding synthetic peptides inhibit phage binding. They, therefore, appear to bind at the mAbs digoxin-binding sites. These data provide the first clear evidence that short polypeptides can serve as surrogates for the low molecular mass hapten digoxin.

[Urinary trypsin inhibitor in pregnant women with normal and pathological course of pregnancy]

Urinary trypin inhibitor concentration (UTI) was measured by Fritz and all method in the groups of women: non-pregnant (I), pregnant (II), in pregnancy complicated by EPH-gestosis (III) and in the prolongated pregnancy (IV). Furthermore, in the urine from the investigated group the index protein/creatinine was established. There was noticed the statistically significant increase in the UTI concentration in II, III, IV groups comparing to the non-pregnant group--I, and the increase in UTI in III and IV group in comparison to group II. The UTI measurement in the pregnant women connected with the index protein/creatinine could be significant for diagnosing of the pathology of pregnancy.

[Changes in arylsulphatase activity (EC 3.1.6.1) in the blood serum and urine in women during pregnancy and in the course of delivery]

By the determination of arylsulphatase A activity (EC 3.1.6.1) in the blood serum and urine obtained from 66 women using the modified method by Lee-Vaupel and Conzelmann it was noticed the increase in the enzyme activity during the pregnancy comparing to the non-pregnant group. The highest enzyme activity was observed in the III trimester of pregnancy. In the following stages of delivery (I, II, III) it was assumed the increase in enzyme activity in urine. The highest enzyme activity in urine was observed in the stage III, and in the serum--in the stage II. It was compared the enzyme activity in primiparae and multiparae proving, that in the serum nd urine this activity is higher in the stages I and II in multiparae, and in the stage III in primiparae.

[Changes in arylsulphatase activity (EC 3.6.1) in the blood serum and urine in women during the pregnancy and in the course of delivery]

By the determination of arylsulphatase A activity (EC 3.1.6.1) in the blood serum and urine obtained from 66 women using the modified method by Lee-Vaupel and Conzelmann it was noticed the increase in the enzyme activity during the pregnancy comparing to the non-pregnant group. The highest enzyme activity was observed in the III trimester of pregnancy. In the following stages of delivery (I, II, III) it was assumed the increase in enzyme activity in urine. The highest enzyme activity in urine was observed in the stage III, and in the serum--in the stage II. It was compared the enzyme activity in primiparae and multiparae proving, that in the serum nd urine this activity is higher in the stages I and II in multiparae, and in the stage III in primiparae.

Antisense oligonucleotides against the alpha-subunit of ENaC decrease lung epithelial cation-channel activity

Amiloride-sensitive Na+ transport by lung epithelia plays a critical role in maintaining alveolar Na+ and water balance. It has been generally assumed that Na+ transport is mediated by the amiloride-sensitive epithelial Na+ channel (ENaC) because molecular biology studies have confirmed the presence of ENaC subunits alpha, beta, and gamma in lung epithelia. However, the predominant Na+-transporting channel reported from electrophysiological studies by most laboratories is a nonselective, high-conductance channel that is very different from the highly selective, low-conductance ENaC reported in other tissues. In our laboratory, single-channel recordings from apical membrane patches from rat alveolar type II (ATII) cells in primary culture reveal a nonselective cation channel with a conductance of 20.6 +/- 1.1 pS and an Na+-to-K+ selectivity of 0.97 +/- 0.07. This channel is inhibited by submicromolar concentrations of amiloride. Thus there is some question about the relationship between the gene product observed with single-channel methods and the cloned ENaC subunits. We have employed antisense oligonucleotide methods to block the synthesis of individual ENaC subunit proteins (alpha, beta, and gamma) and determined the effect of a reduction in the subunit expression on the density of the nonselective cation channel observed in apical membrane patches on ATII cells. Treatment of ATII cells with antisense oligonucleotides inhibited the production of each subunit protein; however, single-channel recordings showed that only the antisense oligonucleotide targeting the alpha-subunit resulted in a significant decrease in the density of nonselective cation channels. Inhibition of the beta- and gamma-subunit proteins alone or together did not cause any changes in the observed channel density. There were no changes in open probability or other channel characteristics. These results support the hypothesis that the alpha-subunit of ENaC alone or in combination with some protein other than the beta- or gamma-subunit protein is the major component of lung alveolar epithelial cation channels.

Identification of the amino acids comprising a surface-exposed epitope within the nucleotide-binding domain of the Na+,K(+)-ATPase using a random peptide library

Monoclonal antibodies that bind native protein can generate considerable information about structure/function relationships, but identification of their epitopes can be problematic. Previously, monoclonal antibody M8-P1-A3 has been shown to bind to the catalytic (alpha) subunit of the Na+,K(+)-ATPase holoenzyme and the synthetic peptide sequence 496-HLLVMK*GAPER-506, which includes Lys 501 (K*), the major site for fluorescein-5'-isothiocyanate labeling of the Na+,K(+)-ATPase. This sequence region of alpha is proposed to comprise a portion of the enzyme's ATP binding domain (Taylor, W. R. & Green, N. W., 1989, Eur. J. Biochem. 179, 241-248). In this study we have determined M8-P1-A3's ability to recognize the alpha-subunit or homologous E1E2-ATPase proteins from different species and tissues in order to deduce the antibody's epitope. In addition the bacteriophage random peptide or "epitope" library, recently developed by Scott and Smith (1990, Science 249, 386-390) and Devlin et al. (Devlin, J. J., Panganiban, L. C., & Devlin, P. E., 1990, Science 249, 404-406), has served as a convenient technique to confirm the species-specificity mapping data and to determine the exact amino acid requirements for antibody binding. The M8-P1-A3 epitope was found to consist of the five amino acid 494-PRHLL-498 sequence stretch of alpha, with residues PRxLx being critical for antibody recognition.

Does antacid prophylaxis prevent upper gastrointestinal bleeding in critically ill patients?

Sixty-five surgical ICU patients at high risk of developing acute erosive gastritis and bleeding received prophylactic antacid treatment to maintain a gastric pH of at least 5.0. A similar control group of 61 patients received no specific prophylaxis. All patients in both groups developed microscopic bleeding; however, microscopic bleeding did not influence outcome. In the control group, eight (13.1%) patients developed moderate visible bleeding, as compared to seven (10.8%) patients in the antacid group, an insignificant difference. A single patient in the control group developed severe GI bleeding due to acute erosive gastritis. Antacid prophylaxis did not prevent macroscopic bleeding and there was no correlation between the number of risk factors in individual patients and the rate of upper GI bleeding. We conclude that antacid is not required to prevent upper GI bleeding in high-risk critically ill patients.