Electrochemically Triggered Release of Reagent to the Proximal Leaflet of a Microcavity Supported Lipid Bilayer

A novel and versatile approach to electrichemically triggering the release of a reagent, β-cyclodextrin (β-CD), selectively to the proximal leaflet of a supported lipid bilayer is described. Selective delivery is achieved by creating a spanning lipid bilayer across a microcavity array and exploiting the irreversible redox disassembly of the host-guest complex formed between thiolated ferrocene (Fc) and β-cyclodextrin (β-CD) in the presence of chloride. Self-assembled monolayers of the ferrocene-alkanethiols were formed regioselectively on the interior surface of highly ordered 2.8 μm cavities while the exterior top surface of the array was blocked with a monolayer of mercaptoethanol. The Fc monolayers were complexed with β-CD or β-CD-conjugated to streptavidin (β-CD-SA). Phospholipid bilayers were then assembled across the array via combined Langmuir-Blodgett/vesicle fusion leading to a spanning bilayer suspended across the aqueous filled microcavities. Upon application of a positive potential, ferrocene is oxidized to ferrocinium cation, disrupting the inclusion complex and leading to the release of the β-CD into the microcavity solution where it diffuses to the lower leaflet of the suspended bilayer. Disassembly of the supramolecular complex within the cavities and binding of the β-CD-SA to a biotinylated bilayer was followed by voltammetry and impedance spectroscopy where it caused a large increase in membrane resistance. For unmodified β-CD, the extraction of cholesterol from a cholesterol containing bilayer was evident in a decrease in the bilayer resistance. For the first time, this direct approach to targeted delivery of a reagent to the proximal layer of a lipid bilayer offers the potential to build models of bidirectional signaling (inside-out vs outside-in) in cell membrane model systems.

Greater sensitivity of the cortical face processing system to perceptually-equated face detection

Face detection, the perceptual capacity to identify a visual stimulus as a face before probing deeper into specific attributes (such as its identity or emotion), is essential for social functioning. Despite the importance of this functional capacity, face detection and its underlying brain mechanisms are not well understood. This study evaluated the roles that the cortical face processing system, which is identified largely through studying other aspects of face perception, play in face detection. Specifically, we used functional magnetic resonance imaging (fMRI) to examine the activations of the fusifom face area (FFA), occipital face area (OFA) and superior temporal sulcus (STS) when face detection was isolated from other aspects of face perception and when face detection was perceptually-equated across individual human participants (n=20). During face detection, FFA and OFA were significantly activated, even for stimuli presented at perceptual-threshold levels, whereas STS was not. During tree detection, however, FFA and OFA were responsive only for highly salient (i.e., high contrast) stimuli. Moreover, activation of FFA during face detection predicted a significant portion of the perceptual performance levels that were determined psychophysically for each participant. This pattern of result indicates that FFA and OFA have a greater sensitivity to face detection signals and selectively support the initial process of face vs. non-face object perception.

Deficient cortical face-sensitive N170 responses and basic visual processing in schizophrenia

BACKGROUND

Face detection, an ability to identify a visual stimulus as a face, is impaired in patients with schizophrenia. It is unclear whether impaired face processing in this psychiatric disorder results from face-specific domains or stems from more basic visual domains. In this study, we examined cortical face-sensitive N170 response in schizophrenia, taking into account deficient basic visual contrast processing.

METHODS

We equalized visual contrast signals among patients (n=20) and controls (n=20) and between face and tree images, based on their individual perceptual capacities (determined using psychophysical methods). We measured N170, a putative temporal marker of face processing, during face detection and tree detection.

RESULTS

In controls, N170 amplitudes were significantly greater for faces than trees across all three visual contrast levels tested (perceptual threshold, two times perceptual threshold and 100%). In patients, however, N170 amplitudes did not differ between faces and trees, indicating diminished face selectivity (indexed by the differential responses to face vs. tree).

CONCLUSION

These results indicate a lack of face-selectivity in temporal responses of brain machinery putatively responsible for face processing in schizophrenia. This neuroimaging finding suggests that face-specific processing is compromised in this psychiatric disorder.

Impaired visual cortical processing of affective facial information in schizophrenia

Facial emotion perception impairment in schizophrenia is currently viewed as abnormal affective processing. Facial emotion perception also relies on visual processing. Yet, visual cortical processing of facial emotion is not well understood in this disorder. We measured perceptual thresholds for detecting facial fear and happiness in patients (n=23) and controls (n=23), and adjusted emotion intensity of facial stimuli (via morphing between images of neutral and emotive expressions) for each subject. We then evaluated activations of the visual cortex and amygdala during the performance of perceptually-equated facial emotion detection tasks. Patients had significantly lower fear- and happiness-induced activations in the visual cortex and amygdala. Activations between the visual cortex and amygdala were largely correlated, but the correlations in patients occurred abnormally early in response time course during fear perception. In schizophrenia, visual processing of facial emotion is deficient and visual and affective processing of negative facial emotion may be prematurely associated.

Visceral obesity stimulates anaphase bridge formation and spindle assembly checkpoint dysregulation in radioresistant oesophageal adenocarcinoma

PURPOSE

Oesophageal adenocarcinoma is an exemplar model of obesity-associated cancer. Locally advanced disease is treated with neoadjuvant chemoradiotherapy, and survival rates are highest in patients demonstrating a pathological response following neoadjuvant therapy. Given that 55 % of oesophageal adenocarcinoma patients are obese, uncovering the effect of adipose tissue on radioresponse is clinically relevant. This study investigates if adipose tissue activates genomic instability events in radioresponsive (OE33P) and radioresistant (OE33R) oesophageal cancer cell lines and tumour samples.

METHODS

OE33R and OE33P were cultured with adipose-conditioned media derived from oesophageal adenocarcinoma patients (n = 10). Anaphase bridges, a marker of genomic instability, were enumerated in both cell lines following treatment with adipose media, and normalised to cell number. Genomic instability is regulated by the spindle assembly complex. Expression of two spindle assembly complex genes (MAD2L2, BUB1B) was assessed using qPCR, and validated in patient tumour specimens from viscerally obese (n = 46) and nonobese patients (n = 41).

RESULTS

Adipose-conditioned media increased anaphase bridging in OE33R (p < 0.0001), with a threefold increase in OE33R compared to OE33P (p < 0.01). Levels of anaphase bridges in OE33R cells correlated with visceral obesity status as measured by waist circumference (R = 0.709, p = 0.03) and visceral fat area (R = 0.794, p = 0.006). Adipose tissue altered expression of MAD2L2 in vitro. In vivo, MAD2L2 expression was higher in viscerally obese oesophageal adenocarcinoma patients compared with nonobese patients (p < 0.05).

CONCLUSIONS

Anaphase bridge levels are influenced by obesity and radiosensitivity status in oesophageal adenocarcinoma. Furthermore, visceral adipose-conditioned media stimulates dysregulation of the spindle assembly complex in oesophageal adenocarcinoma patients.

Protocol for a randomised controlled trial of an outreach support program for family carers of older people discharged from hospital

BACKGROUND

Presentations to hospital of older people receiving family care at home incur substantial costs for patients, families, and the health care system, yet there can be positive carer outcomes when systematically assessing/addressing their support needs, and reductions in older people's returns to hospital attributed to appropriate discharge planning. This study will trial the Further Enabling Care at Home program, a 2-week telephone outreach initiative for family carers of older people returning home from hospital. Hypotheses are that the program will (a) better prepare families to sustain their caregiving role and (b) reduce patients' re-presentations/readmissions to hospital, and/or their length of stay; also that reduced health system costs attributable to the program will outweigh costs of its implementation.

METHODS/DESIGN

In this randomised controlled trial, family carers of older patients aged 70+ discharged from a Medical Assessment Unit in a Western Australian tertiary hospital, plus the patients themselves, will be recruited at discharge (N = 180 dyads). Carers will be randomly assigned (block allocation, assessors blinded) to receive usual care (control) or the new program (intervention). The primary outcome is the carer's self-reported preparedness for caregiving (Preparedness for Caregiving Scale administered within 4 days of discharge, 2-3 weeks post-discharge, 6 weeks post-discharge). To detect a clinically meaningful change of two points with 80 % power, 126 carers need to complete the study. Patients' returns to hospital and subsequent length of stay will be ascertained for a minimum of 3 months after the index admission. Regression analyses will be used to determine differences in carer and patient outcomes over time associated with the group (intervention or control). Data will be analysed using an Intention to Treat approach. A qualitative exploration will examine patients' and their family carers' experiences of the new program (interviews) and explore the hospital staff's perceptions (focus groups). Process evaluation will identify barriers to, and facilitators of, program implementation. A comprehensive economic evaluation will determine cost consequences.

DISCUSSION

This study investigates a novel approach to identifying and addressing family carers' needs following discharge from hospital of the older person receiving care. If successful, the program has potential to be incorporated into routine post-discharge support.

TRIAL REGISTRATION

Australian and New Zealand Clinical Trial Registry: ACTRN12614001174673 .

Aqueous-filled polymer microcavity arrays: versatile & stable lipid bilayer platforms offering high lateral mobility to incorporated membrane proteins

A robust new supported cell membrane model is described comprising lipid bilayers supported on aqueous filled spherical cap pores in PDMS, both lipid and reconstituted membrane proteins diffuse unhindered by the underlying support.

Quadrupole mass filter operation under the influence of magnetic field

This work demonstrates resolution enhancement of a quadrupole mass filter (QMF) under the influence of a static magnetic field. Generally, QMF resolution can be improved by increasing the number of rf cycles an ion experiences when passing through the mass filter. In order to improve the resolution, the dimensions of the QMF or the operating parameters need to be changed. However, geometric modifications to improve performance increase the manufacturing cost and usually the size of the instrument. By applying a magnetic field, a low-cost, small footprint instrument with reduced power requirements can be realized. Significant improvement in QMF resolution was observed experimentally for certain magnetic field conditions, and these have been explained in terms of our theoretical model developed at the University of Liverpool. This model is capable of accurate simulation of spectra allowing the user to specify different values of mass spectrometer dimensions and applied input signals. The model predicts enhanced instrument resolution R>26,000 for a CO2 and N2 mixture with a 200-mm long mass filter operating in stability zone 3 via application of an axial magnetic field.

Experiences, understandings and support needs of family carers of older patients with delirium: a descriptive mixed methods study in a hospital delirium unit

BACKGROUND

Delirium is common in older patients. Little is known of support needs of families of older hospital patients with delirium.

AIMS AND OBJECTIVES

To inform nursing practice, we sought to describe families' experiences, understanding of delirium and delirium care, and support needs.

DESIGN

Descriptive mixed methods.

METHODS

Review of questionnaire items used with families of people with terminal delirium informed development of a new questionnaire to evaluate the support needs in our study population. In a tertiary hospital delirium unit, we recruited 17 family carers of older patients with (non-terminal) delirium to respond to this questionnaire. Twelve participants (11 female) also took part in interviews addressing the study's aims. Descriptive statistics were calculated and thematic analysis was undertaken.

RESULTS

From the survey, key family issues included distress about the patient's condition, worries about future care, and a need for more information about how the patient might feel and how families could support the patient. Themes from interviews included The admission experience, Worries and concerns, Feeling supported, and The discharge experience. Limited understanding of delirium underpinned all themes. Families experienced shock and sadness at the change in the patient; they were reassured by the specialist care but needed more information about delirium, its effects and outcomes, and how they could help with care. Meeting long-term postdischarge needs was a key concern.

CONCLUSIONS

In this study, families with a hospitalised older relative who had delirium described a distressing experience and needs for informational support. Further research is needed outside of delirium-specific units and in samples including a greater proportion of male relatives.

IMPLICATIONS FOR PRACTICE

Nurses should work within the interdisciplinary team to ensure a planned, sensitive and timely approach to informing the patient's family about delirium and its implications for their relative, recognising the family carer's role and likely distress.

Guidelines for a palliative approach for aged care in the community setting: A suite of resources

In Australia, many people ageing in their own homes are becoming increasingly frail and unwell, approaching the end of life. A palliative approach, which adheres to palliative care principles, is often appropriate. These principles provide a framework for proactive and holistic care in which quality of life and of dying is prioritised, as is support for families. A palliative approach can be delivered by the general practitioner working with the community aged care team, in collaboration with family carers. Support from specialist palliative care services is available if necessary.The Guidelines for a Palliative Approach for Aged Care in the Community Setting were published by the Australian Government Department of Health and Ageing to inform practice in this area. There are three resource documents. The main document provides practical evidence based guidelines, good practice points, tools, and links to resources. This document is written for general practitioners, nurses, social workers, therapists, pastoral care workers, and other health professionals and responded to needs identified during national consultation. Evidence based guidelines were underpinned by systematic reviews of the research literature. Good practice points were developed from literature reviews and expert opinion. Two 'plain English' booklets were developed in a process involving consumer consultation; one is for older people and their families, the other for care workers.The resources are intended to facilitate home care that acknowledges and plans for the client's deteriorating functional trajectory and inevitable death. At a time when hospitals and residential aged care facilities are under enormous pressure as the population ages, such a planned approach makes sense for the health system as a whole. The approach also makes sense for older people who wish to die in their own homes. Family needs are recognised and addressed. Unnecessary hospitalisations or residential placements and clinically futile interventions are also minimised.

The mycotoxin patulin increases colonic epithelial permeability in vitro

The gastrointestinal lumen is directly exposed to dietary contaminants, including patulin, a mycotoxin produced by moulds. Patulin is known to increase permeability across intestinal Caco-2 monolayers. This study aimed to determine the effect of patulin on permeability, ion transport and morphology in isolated rat colonic mucosae. Mucosal sheets were mounted in Ussing chambers and voltage clamped. Apical addition of patulin (100-500 μM) rapidly reduced transepithelial electrical resistance (TEER) and increased permeability to [(14)C] mannitol (2.9-fold). Patulin also inhibited carbachol-induced electrogenic chloride secretion and histological evidence of mucosal damage was observed. To examine potential mechanisms of action of patulin on colonic epithelial cells, high-content analysis of Caco-2 cells was performed and this novel, quantitative fluorescence-based approach confirmed its cytotoxic effects. With regard to time course, the cytotoxicity determined by high content analysis took longer than the almost immediate reduction of electrical resistance in isolated mucosal sheets. These data indicate patulin is not only cytotoxic to enterocytes but also has the capacity to directly alter permeability and ion transport in intact intestinal mucosae. These data corroborate and extend findings in intestinal cell culture monolayers, and further suggest that safety limits on consumption of patulin may be warranted.