Home-monitoring for neovascular age-related macular degeneration in older adults within the UK: the MONARCH diagnostic accuracy study.

Background: Most neovascular age-related macular degeneration treatments involve long-term follow-up of disease activity. Home monitoring would reduce the burden on patients and those they depend on for transport, and release clinic appointments for other patients. The study aimed to evaluate three home-monitoring tests for patients to use to detect active neovascular age-related macular degeneration compared with diagnosing active neovascular age-related macular degeneration by hospital follow-up. Objectives: There were five objectives: Estimate the accuracy of three home-monitoring tests to detect active neovascular age-related macular degeneration. Determine the acceptability of home monitoring to patients and carers and adherence to home monitoring. Explore whether inequalities exist in recruitment, participants' ability to self-test and their adherence to weekly testing during follow-up. Provide pilot data about the accuracy of home monitoring to detect conversion to neovascular age-related macular degeneration in fellow eyes of patients with unilateral neovascular age-related macular degeneration. Describe challenges experienced when implementing home-monitoring tests. Design: Diagnostic test accuracy cohort study, stratified by time since starting treatment. Setting: Six United Kingdom Hospital Eye Service macular clinics (Belfast, Liverpool, Moorfields, James Paget, Southampton, Gloucester). Participants: Patients with at least one study eye being monitored by hospital follow-up. Reference standard: Detection of active neovascular age-related macular degeneration by an ophthalmologist at hospital follow-up. Index tests: KeepSight Journal: paper-based near-vision tests presented as word puzzles. MyVisionTrack®: electronic test, viewed on a tablet device. MultiBit: electronic test, viewed on a tablet device. Participants provided test scores weekly. Raw scores between hospital follow-ups were summarised as averages. Results: Two hundred and ninety-seven patients (mean age 74.9 years) took part. At least one hospital follow-up was available for 317 study eyes, including 9 second eyes that became eligible during follow-up, in 261 participants (1549 complete visits). Median testing frequency was three times/month. Estimated areas under receiver operating curves were < 0.6 for all index tests, and only KeepSight Journal summary score was significantly associated with the lesion activity (odds ratio = 3.48, 95% confidence interval 1.09 to 11.13, p = 0.036). Older age and worse deprivation for home address were associated with lower participation (χ2 = 50.5 and 24.3, respectively, p < 0.001) but not ability or adherence to self-testing. Areas under receiver operating curves appeared higher for conversion of fellow eyes to neovascular age-related macular degeneration (0.85 for KeepSight Journal) but were estimated with less precision. Almost half of participants called a study helpline, most often due to inability to test electronically. Limitations: Pre-specified sample size not met; participants' difficulties using the devices; electronic tests not always available. Conclusions: No index test provided adequate test accuracy to identify lesion diagnosed as active in follow-up clinics. If used to detect conversion, patients would still need to be monitored at hospital. Associations of older age and worse deprivation with study participation highlight the potential for inequities with such interventions. Provision of reliable electronic testing was challenging. Future work: Future studies evaluating similar technologies should consider: Independent monitoring with clear stopping rules based on test performance. Deployment of apps on patients' own devices since providing devices did not reduce inequalities in participation and complicated home testing. Alternative methods to summarise multiple scores over the period preceding a follow-up. Trial registration: This trial is registered as ISRCTN79058224. Funding: This award was funded by the National Institute of Health and Care Research (NIHR) Health Technology Assessment programme (NIHR award ref: 15/97/02) and is published in full in Health Technology Assessment; Vol. 28, No. 32. See the NIHR Funding and Awards website for further award information.

Treatment for neovascular age-related macular degeneration, the most common cause of sight loss in those over 50 years, involves regular eye injections and frequent follow-up appointments. This is inconvenient for patients and causes capacity issues in the hospital eye service. Finding tests that could be undertaken at home that could detect if a further injection and hospital appointment was required or not would increase capacity to see those at highest risk of sight loss and also reduce the burden on patients and their carers. We investigated three different visual function tests, one paper-based and two applications on an iPod Touch_TM tablet (Apple, Cupertino, CA, USA). We wanted to see if they could detect an increase in disease activity that would require treatment, compared to the decision by a retinal specialist at a traditional hospital eye outpatient visit based on clinical examination and retinal imaging. To encourage those without a smartphone or home internet to participate, we provided both an iPod Touch and Mobile Wireless-Fidelity device with a mobile contract. None of the tests performed well enough to safely monitor patients at home. Those who were willing to participate tended to be younger, had previous experience of using smartphones, sending e-mail and internet access and were more well-off than those who chose not to participate. Some participants also experienced difficulties with the devices provided and successfully uploading the data which were not related to the extent of previous information technology experience. There were also significant technical challenges for the research team. The study helpline was used heavily, considerably more than we anticipated. These tests are not ready to be used in this context. Future studies involving mobile health technology need to carefully consider how to reach those unlikely to participate and provide sufficient technical support to support long-term follow-up.

Acceptability of Home Monitoring for Neovascular Age-Related Macular Degeneration Reactivation: A Qualitative Study.

This study formed part of a diagnostic test accuracy study to quantify the ability of three index home monitoring (HM) tests (one paper-based and two digital tests) to identify reactivation in Neovascular age-related macular degeneration (nAMD). The aim of the study was to investigate views about acceptability and explore adherence to weekly HM. Semi-structured interviews were held with 98 patients, family members, and healthcare professionals. A thematic approach was used which was informed by theories of technology acceptance. Various factors influenced acceptability including a patient's understanding about the purpose of monitoring. Training and ongoing support were regarded as essential for overcoming unfamiliarity with digital technology. Findings have implications for implementation of digital HM in the care of older people with nAMD and other long-term conditions.

Home-Monitoring Vision Tests to Detect Active Neovascular Age-Related Macular Degeneration.

Importance: Most neovascular age-related macular degeneration (nAMD) treatments involve long-term follow-up of disease activity. Home-monitoring would reduce the burden on patients and their caregivers and release clinic capacity. Objective: To evaluate 3 vision home-monitoring tests for patients to use to detect active nAMD compared with diagnosing active nAMD at hospital follow-up during the after-treatment monitoring phase. Design, Setting, and Participants: This was a diagnostic test accuracy study wherein the reference standard was detection of active nAMD by an ophthalmologist at hospital follow-up. The 3 home-monitoring tests evaluated included the following: (1) the KeepSight Journal (KSJ [International Macular and Retinal Foundation]), which contains paper-based near-vision tests presented as word puzzles, (2) the MyVisionTrack (mVT [Genentech]) vision-monitoring mobile app, viewed on an Apple mobile operating system-based device, and (3) the MultiBit (MBT [Visumetrics]) app, viewed on an Apple mobile operating system-based device. Participants were asked to test weekly; mVT and MBT scores were transmitted automatically, and KSJ scores were returned to the research office every 6 months. Raw scores between hospital follow-ups were summarized as averages. Patients were recruited from 6 UK hospital eye clinics and were 50 years and older with at least 1 eye first treated for active nAMD for at least 6 months or longer to a maximum of 42 months before approach. Participants were stratified by time since starting treatment. Study data were analyzed from May to September 2021. Exposures: The KSJ, mVT, and MBT were compared with the reference standard (in-hospital ophthalmologist examination). Main Outcomes and Measures: Estimated area under receiver operating characteristic curve (AUROC). The study had 90% power to detect a difference of 0.06, or 80% power to detect a difference of 0.05, if the AUROC for 2 tests was 0.75. Results: A total of 297 patients (mean [SD] age, 74.9 [6.6] years; 174 female [58.6%]) were included in the study. At least 1 hospital follow-up was available for 312 study eyes in 259 participants (1549 complete visits). Median (IQR) home-monitoring testing frequency was 3 (1-4) times per month. Estimated AUROC was less than 0.6 for all home-monitoring tests, and only the KSJ summary score was associated with lesion activity (odds ratio, 3.48; 95% CI, 1.09-11.13; P = .04). Conclusions and Relevance: Results suggest that no home-monitoring vision test evaluated provided satisfactory diagnostic accuracy to identify active nAMD diagnosed in hospital eye service follow-up clinics. Implementing any of these evaluated tests, with ophthalmologists only reviewing test positives, would mean most active lesions were missed, risking unnecessary sight loss.

Inequalities in Uptake and Use of Digital Applications for Home-Monitoring of Neovascular Age-Related Macular Degeneration in an Elderly Visually Impaired Population: The MONARCH Study.

Purpose: To describe inequalities in the Monitoring for Neovascular Age-related Macular Degeneration Reactivation at Home (MONARCH) diagnostic test accuracy study for: recruitment; participants' ability to self-test; and adherence to testing using digital applications during follow-up. Methods: Home-monitoring vision tests included two tests implemented as software applications (apps: MyVisionTrack and MultiBit) on an iPod Touch device. Patients were provided with all hardware required to participate (iPod and MIFI device) and trained to use the apps. Regression models estimated associations of age, sex, Index of Multiple Deprivation, strata of time since first diagnosis, and baseline visual acuity at study entry on outcomes of willingness to participate, ability to perform tests, and adherence to weekly testing. Results: A minority of patients who were approached were willing-in-principle to participate. Increasing age was associated with being unwilling-in-principle to participate. Patients from the most deprived areas had a 47% decrease in odds of being willing compared to those from the middle quintile deprived areas (odds ratio, 0.53; 95% confidence interval = 0.32, 0.88). Increasing age and worse deprivation were not consistently associated either with ability to self-monitor with the index tests, or adherence to weekly testing. Conclusions: Associations of increasing age and worse deprivation index were associated with unwillingness-in-principle to participate despite the provision of hardware' highlighting the potential for inequality with interventions of the kind evaluated. Translational Relevance: The clear evidence of inequalities in participation should prompt future research on ways to encourage adoption of mobile health technologies by underserved populations.

Descriptive study of the challenges when implementing an app for patients with neovascular age-related macular degeneration to monitor their vision at home.

OBJECTIVES: Remote monitoring of health has the potential to reduce the burden to patients of face-to-face appointments and make healthcare more efficient. Apps are available for patients to self-monitor vision at home, for example, to detect reactivation of age-related macular degeneration (AMD). Describing the challenges when implementing apps for self-monitoring of vision at home was an objective of the MONARCH study to evaluate two vision-monitoring apps on an iPod Touch (Multibit and MyVisionTrack). DESIGN: Diagnostic Test Accuracy study. SETTING: Six UK hospitals. METHODS: The study provides an example of the real-world implementation of such apps across health sectors in an older population. Challenges described include the following: (1) frequency and reason for incoming calls made to a helpline and outgoing calls made to participants; (2) frequency and duration of events responsible for the tests being unavailable; and (3) other technical and logistical challenges. RESULTS: Patients (n=297) in the study were familiar with technology; 252/296 (85%) had internet at home and 197/296 (67%) had used a smartphone. Nevertheless, 141 (46%) called the study helpline, more often than anticipated. Of 435 reasons for calling, all but 42 (10%) related to testing with the apps or hardware, which contributed to reduced adherence. The team made at least one call to 133 patients (44%) to investigate why data had not been transmitted. Multibit and MyVisionTrack apps were unavailable for 15 and 30 of 1318 testing days for reasons which were the responsibility of the app providers. Researchers also experienced technical challenges with a multiple device management system. Logistical challenges included regulations for transporting lithium-ion batteries and malfunctioning chargers. CONCLUSIONS: Implementation of similar technologies should incorporate a well-resourced helpline and build in additional training time for participants and troubleshooting time for staff. There should also be robust evidence that chosen technologies are fit for the intended purpose. TRIAL REGISTRATION NUMBER: ISRCTN79058224.

Restraining Quiescence Release-Related Ageing in Plant Cells: A Case Study in Carrot.

The blackening of cut carrots causes substantial economic losses to the food industry. Blackening was not observed in carrots that had been stored underground for less than a year, but the susceptibility to blackening increased with the age of the carrots that were stored underground for longer periods. Samples of black, border, and orange tissues from processed carrot batons and slices, prepared under industry standard conditions, were analyzed to identify the molecular and metabolic mechanisms underpinning processing-induced blackening. The black tissues showed substantial molecular and metabolic rewiring and large changes in the cell wall structure, with a decreased abundance of xyloglucan, pectins (homogalacturonan, rhamnogalacturonan-I, galactan and arabinan), and higher levels of lignin and other phenolic compounds when compared to orange tissues. Metabolite profiling analysis showed that there was a major shift from primary to secondary metabolism in the black tissues, which were depleted in sugars, amino acids, and tricarboxylic acid (TCA) cycle intermediates but were rich in phenolic compounds. These findings suggest that processing triggers a release from quiescence. Transcripts encoding proteins associated with secondary metabolism were less abundant in the black tissues, but there were no increases in transcripts associated with oxidative stress responses, programmed cell death, or senescence. We conclude that restraining quiescence release alters cell wall metabolism and composition, particularly regarding pectin composition, in a manner that increases susceptibility to blackening upon processing.

Home vision monitoring in patients with maculopathy: current and future options for digital technologies.

Patients with macular pathology, including that caused by age-related macular degeneration and diabetic macular oedema, must attend frequent in-clinic monitoring appointments to detect onset of disease activity requiring treatment and to monitor progression of existing disease. In-person clinical monitoring places a significant burden on patients, caregivers and healthcare systems and is limited in that it only provides clinicians with a snapshot of the patient's disease status. The advent of remote monitoring technologies offers the potential for patients to test their own retinal health at home in collaboration with clinicians, reducing the need for in-clinic appointments. In this review we discuss visual function tests, both existing and novel, that have the potential for remote use and consider their suitability for discriminating the presence of disease and progression of disease. We then review the clinical evidence supporting the use of mobile applications for monitoring of visual function from clinical development through to validation studies and real-world implementation. This review identified seven app-based visual function tests: four that have already received some form of regulatory clearance and three under development. The evidence included in this review shows that remote monitoring offers great potential for patients with macular pathology to monitor their condition from home, reducing the need for burdensome clinic visits and expanding clinicians' understanding of patients' retinal health beyond traditional clinical monitoring. In order to instil confidence in the use of remote monitoring in both patients and clinicians further longitudinal real-world studies are now warranted.

Eye tracking: empirical foundations for a minimal reporting guideline.

In this paper, we present a review of how the various aspects of any study using an eye tracker (such as the instrument, methodology, environment, participant, etc.) affect the quality of the recorded eye-tracking data and the obtained eye-movement and gaze measures. We take this review to represent the empirical foundation for reporting guidelines of any study involving an eye tracker. We compare this empirical foundation to five existing reporting guidelines and to a database of 207 published eye-tracking studies. We find that reporting guidelines vary substantially and do not match with actual reporting practices. We end by deriving a minimal, flexible reporting guideline based on empirical research (Section "An empirically based minimal reporting guideline").

Measurement of Saccade Parameters in Relation to Adaptation to Homonymous Hemianopia.

Purpose: To report saccade parameters in participants during adaptation to post-stroke homonymous hemianopia. Methods: In a prospective observational case cohort study, adult stroke survivors with new onset homonymous hemianopia were recruited. Using quantitative measurement, saccade parameters were measured and compared between the hemianopic and non-hemianopic sides. Two participants with longitudinal measurements were compared with age-matched controls. Results: Of 144 clinical study participants, quantitative saccade measurements were only possible in 14 due to an inability to visualise targets on the hemianopic side in the majority. In 9 of the 14 participants, at four weeks post-stroke, mean (±SD) saccade latency was significantly longer to the hemianopic (328.4 ± 105.9 ms) compared to the non-hemianopic side (234.7 ± SD53.6 ms; t = 4.2, df = 8, p = 0.003). The number of correct saccadic responses out of 50 was significantly lower to the hemianopic side (36.6 ± SD14.1) in comparison to the non-hemianopic side (44.4 ± SD7.5; t = -3.1, df = 8, p = 0.014). In two participants studied over an eight-week time period, saccadic differences to the hemianopic side persisted despite apparent recovery of visual field. Conclusion: As participants with residual visual field loss were unable to perform quantitative assessments, the widespread use of this approach in this setting is limited. However, in those whom measurements were possible, there were statistically significant differences in saccade parameters between hemianopic and non-hemianopic sides that persisted post-visual recovery. Exploration of saccades in relation to adaptation to hemianopia and response to saccadic scanning/search training requires further examination.

Patient Acceptability of Home Monitoring for Neovascular Age-Related Macular Degeneration Reactivation: A Qualitative Study.

Neovascular age-related macular degeneration (nAMD) is a chronic, progressive condition and the commonest cause of visual disability in older adults. This study formed part of a diagnostic test accuracy study to quantify the ability of three index home monitoring (HM) tests (one paper-based and two digital tests) to identify reactivation in nAMD. The aim of this qualitative research was to investigate patients' or participants' views about acceptability and explore adherence to weekly HM. Semi-structured interviews were held with 78/297 participants (26%), with close family members (n = 11) and with healthcare professionals involved in training participants in HM procedures (n = 9) (n = 98 in total). A directed thematic analytical approach was applied to the data using a deductive and inductive coding framework informed by theories of technology acceptance. Five themes emerged related to: 1. The role of HM; 2. Suitability of procedures and instruments; 3. Experience of HM; 4. Feasibility of HM in usual practice; and 5. Impediments to patient acceptability of HM. Various factors influenced acceptability including a patient's understanding about the purpose of monitoring. While initial training and ongoing support were regarded as essential for overcoming unfamiliarity with use of digital technology, patients viewed HM as relatively straightforward and non-burdensome. There is a need for further research about how use of performance feedback, level of support and nature of tailoring might facilitate further the implementation of routinely conducted HM. Home monitoring was acceptable to patients and they recognised its potential to reduce clinic visits during non-active treatment phases. Findings have implications for implementation of digital HM in the care of older people with nAMD and other long-term conditions.

The COVID-19 Pandemic and Ophthalmic Care: A Qualitative Study of Patients with Neovascular Age-Related Macular Degeneration (nAMD).

Concerns have been expressed about the relationship between reduced levels of health care utilisation and the COVID-19 pandemic. This study aimed to elicit and explore the views of patients with neovascular age-related macular degeneration (nAMD) regarding the COVID-19 pandemic and their ophthalmic care. Semi-structured telephone interviews were conducted with thirty-five patients with nAMD taking part in a larger diagnostic accuracy study of home-monitoring tests. Participants were recruited using maximum variation sampling to capture a range of key characteristics including age, gender and time since initial treatment. Transcribed interview data were analysed using a deductive and inductive thematic approach. Three themes emerged from the analysis: i. access to eye clinic care. ii. COVID-19-mitigating factors and care delivery and iii. social and personal circumstances. Participants reported anxieties about cancelled or delayed appointments, limited communication from clinic-based services about appointments, and the impact of this on their ongoing care. Despite these concerns, there was apprehension about attending appointments due to infection risk and a perception that nAMD patients are a 'high risk' group. Views of those who attended clinics during the study period were, however, positive, with social distancing and infection control measures providing reassurance. These findings contribute to our understanding about experiences of patients with nAMD during the COVID-19 pandemic and may have potential implications for future planning of care services in similar circumstances. Innovative approaches may be required to address issues related to access to care, including concerns about delayed or cancelled appointments.

Altered properties and structures of root exudate polysaccharides in a root hairless mutant of barley.

Root exudates and rhizosheaths of attached soil are important features of growing roots. To elucidate factors involved in rhizosheath formation, wild-type (WT) barley (Hordeum vulgare L. cv. Pallas) and a root hairless mutant, bald root barley (brb), were investigated with a combination of physiological, biochemical, and immunochemical assays. When grown in soil, WT barley roots bound ∼5-fold more soil than brb per unit root length. High molecular weight (HMW) polysaccharide exudates of brb roots had less soil-binding capacity than those of WT root exudates. Carbohydrate and glycan monoclonal antibody analyses of HMW polysaccharide exudates indicated differing glycan profiles. Relative to WT plants, root exudates of brb had reduced signals for arabinogalactan-protein (AGP), extensin, and heteroxylan epitopes. In contrast, the root exudate of 2-week-old brb plants contained ∼25-fold more detectable xyloglucan epitope relative to WT. Root system immunoprints confirmed the higher levels of release of the xyloglucan epitope from brb root apices and root axes relative to WT. Epitope detection with anion-exchange chromatography indicated that the increased detection of xyloglucan in brb exudates was due to enhanced abundance of a neutral polymer. Conversely, brb root exudates contained decreased amounts of an acidic polymer, with soil-binding properties, containing the xyloglucan epitope and glycoprotein and heteroxylan epitopes relative to WT. We, therefore, propose that, in addition to physically structuring soil particles, root hairs facilitate rhizosheath formation by releasing a soil-binding polysaccharide complex.

Confirmation of age-related alterations in inhibitory control using a modified minimally delayed oculomotor response (MDOR) task.

Considerable effort has been made to measure and understand the effects of ageing on inhibitory control using a range of behavioural tasks. In the minimally delayed oculomotor response (MDOR) task, participants are presented with a simple visual target step with variable target display duration (TDD), and instructed to saccade to the target not when it appears (a prosaccade response), but when it disappears (i.e., on target offset). Using this task, we recently found higher error rates and longer latencies for correct responses in older compared to younger participants. Here we have used a modified MDOR task, in which participants were presented with static placeholders identifying potential target positions (increasing spatial information), and three TDDs rather than two (reducing temporal predictability). We found that the yield of analysable trials was generally higher with this modified task and in 28 older (mean ± SD age: 65 ± 7 y) and 25 younger (26 ± 7 y) participants the total overall error rate was again higher in the older group (30 ± 18% vs. 16 ± 11%). An analysis of the temporal distribution of responses demonstrated a pronounced peak in error production around 150 ms (young) or 200 ms (old) after target onset. When we recalculated the error rate focusing on these errors, it was again significantly higher in the older group. The latency of correct responses (to offsets) was significantly increased in the older group, although much of this increase was accounted for by expected age-related visuomotor slowing. However, both latency and distribution data suggested that while older participants could generate increased levels of inhibition, they could not maintain these levels as efficiently as the younger participants. In 24 participants (15 old, 9 young) who completed both versions of the MDOR task, neither latency nor error rates differed significantly between versions. These results confirm an inhibitory control deficit in healthy older participants, and suggest that the dynamics of inhibitory control are also affected by ageing. The modified MDOR task yields more data while not altering basic performance parameters.

Monitoring for neovascular age-related macular degeneration (AMD) reactivation at home: the MONARCH study.

AIMS: This study aims to quantify the diagnostic test-accuracy of three visual function self-monitoring tests for detection of active disease in patients with neovascular age-related macular degeneration (nAMD) when compared with usual care. An integrated qualitative study will investigate the acceptability of these home-based testing strategies. METHODS: All consenting participants are provided with an equipment pack containing an iPod touch with two vision test applications installed and a paper journal of reading tests. Participants self-monitor their vision at home each week with all three tests for 12-18 months. Usual care continues over this period. Key eligibility criteria are: age ≥50 years; at least one eye with AMD with ≥6-≤42 months since first AMD treatment; and vision not worse than Snellen 6/60, LogMAR 1.04 or 33 letters. The primary outcome, and reference standard, is diagnosis of active disease during usual care monitoring in the Hospital Eye Service. Secondary outcomes include duration of study participation, ability of participants to do the tests, adherence to weekly testing and acceptability of the tests to participants. CONCLUSIONS: Recruitment is in progress at five NHS centres. Challenges in procuring equipment, setting up the devices and transporting devices containing lithium batteries to participating sites delayed the start of recruitment. The study will describe the performance of the tests self-administered at home in detecting active disease compared to usual care monitoring. It will also describe the feasibility of the NHS implementing patient-administered electronic tests or similar applications at home for monitoring health.

Cereal root exudates contain highly structurally complex polysaccharides with soil-binding properties.

Rhizosheaths function in plant-soil interactions, and are proposed to form due to a mix of soil particle entanglement in root hairs and the action of adhesive root exudates. The soil-binding factors released into rhizospheres to form rhizosheaths have not been characterised. Analysis of the high-molecular-weight (HMW) root exudates of both wheat and maize plants indicate the presence of complex, highly branched polysaccharide components with a wide range of galactosyl, glucosyl and mannosyl linkages that do not directly reflect cereal root cell wall polysaccharide structures. Periodate oxidation indicates that it is the carbohydrate components of the HMW exudates that have soil-binding properties. The root exudates contain xyloglucan (LM25), heteroxylan (LM11/LM27) and arabinogalactan-protein (LM2) epitopes, and sandwich-ELISA evidence indicates that, in wheat particularly, these can be interlinked in multi-polysaccharide complexes. Using wheat as a model, exudate-binding monoclonal antibodies have enabled the tracking of polysaccharide release along root axes of young seedlings, and their presence at root hair surfaces and in rhizosheaths. The observations indicate that specific root exudate polysaccharides, distinct from cell wall polysaccharides, are adhesive factors secreted by root axes, and that they contribute to the formation and stabilisation of cereal rhizosheaths.

Pectic galactan affects cell wall architecture during secondary cell wall deposition.

MAIN CONCLUSION: ß-(1,4)-galactan determines the interactions between different matrix polysaccharides and cellulose during the cessation of cell elongation. Despite recent advances regarding the role of pectic ß-(1,4)-galactan neutral side chains in primary cell wall remodelling during growth and cell elongation, little is known about the specific function of this polymer in other developmental processes. We have used transgenic Arabidopsis plants overproducing chickpea ßI-Gal ß-galactosidase under the 35S CaMV promoter (35S::ßI-Gal) with reduced galactan levels in the basal non-elongating floral stem internodes to gain insight into the role of ß-(1,4)-galactan in cell wall architecture during the cessation of elongation and the beginning of secondary growth. The loss of galactan mediated by ßI-Gal in 35S::ßI-Gal plants is accompanied by a reduction in the levels of KOH-extracted xyloglucan and an increase in the levels of xyloglucan released by a cellulose-specific endoglucanase. These variations in cellulose-xyloglucan interactions cause an altered xylan and mannan deposition in the cell wall that in turn results in a deficient lignin deposition. Considering these results, we can state that ß-(1,4)-galactan plays a key structural role in the correct organization of the different domains of the cell wall during the cessation of growth and the early events of secondary cell wall development. These findings reinforce the notion that there is a mutual dependence between the different polysaccharides and lignin polymers to form an organized and functional cell wall.

Age-related alterations in inhibitory control investigated using the minimally delayed oculomotor response task.

Healthy, older adults are widely reported to experience cognitive decline, including impairments in inhibitory control. However, this general proposition has recently come under scrutiny because ageing effects are highly variable between individuals, are task dependent, and are sometimes not distinguished from general age-related slowing. We recently developed the minimally delayed oculomotor response (MDOR) task in which participants are presented with a simple visual target step, and instructed to saccade not to the target when it appears (a prosaccade response), but when it disappears (i.e. on target offset). Varying the target display duration (TDD) prevents offset timing being predictable from the time of target onset, and saccades prior to the offset are counted as errors. A comparison of MDOR task performance in a group of 22 older adults (mean age 62 years, range 50-72 years) with that in a group of 39 younger adults (22 years, range 19-27 years) demonstrated that MDOR latency was significantly increased in the older group by 34-68 ms depending on TDD. However, when MDOR latencies were corrected by subtracting the latency observed in a standard prosaccade task, the latency difference between groups was abolished. There was a larger latency modulation with TDD in the older group which was observed even when their generally longer latencies were taken into account. Error rates were significantly increased in the older group. An analysis of the timing distribution of errors demonstrated that most errors were failures to inhibit responses to target onsets. When error distributions were used to isolate clear inhibition failures from other types of error, the older group still exhibited significantly higher error rates as well as a higher residual error rate. Although MDOR latency in older participants may largely reflect a general slowing in the oculomotor system with age, both the latency modulation and error rate results are consistent with an age-related inhibitory control deficit. How this relates to performance on other inhibitory control tasks remains to be investigated.

Spatial Linear Mixed Effects Modelling for OCT Images: SLME Model.

Much recent research focuses on how to make disease detection more accurate as well as "slimmer", i.e., allowing analysis with smaller datasets. Explanatory models are a hot research topic because they explain how the data are generated. We propose a spatial explanatory modelling approach that combines Optical Coherence Tomography (OCT) retinal imaging data with clinical information. Our model consists of a spatial linear mixed effects inference framework, which innovatively models the spatial topography of key information via mixed effects and spatial error structures, thus effectively modelling the shape of the thickness map. We show that our spatial linear mixed effects (SLME) model outperforms traditional analysis-of-variance approaches in the analysis of Heidelberg OCT retinal thickness data from a prospective observational study, involving 300 participants with diabetes and 50 age-matched controls. Our SLME model has a higher power for detecting the difference between disease groups, and it shows where the shape of retinal thickness profiles differs between the eyes of participants with diabetes and the eyes of healthy controls. In simulated data, the SLME model demonstrates how incorporating spatial correlations can increase the accuracy of the statistical inferences. This model is crucial in the understanding of the progression of retinal thickness changes in diabetic maculopathy to aid clinicians for early planning of effective treatment. It can be extended to disease monitoring and prognosis in other diseases and with other imaging technologies.

Sticky mucilages and exudates of plants: putative microenvironmental design elements with biotechnological value.

Plants produce a wide array of secretions both above and below ground. Known as mucilages or exudates, they are secreted by seeds, roots, leaves and stems and fulfil a variety of functions including adhesion, protection, nutrient acquisition and infection. Mucilages are generally polysaccharide-rich and often occur in the form of viscoelastic gels and in many cases have adhesive properties. In some cases, progress is being made in understanding the structure-function relationships of mucilages such as for the secretions that allow growing ivy to attach to substrates and the biosynthesis and secretion of the mucilage compounds of the Arabidopsis seed coat. Work is just beginning towards understanding root mucilage and the proposed adhesive polymers involved in the formation of rhizosheaths at root surfaces and for the secretions involved in host plant infection by parasitic plants. In this article, we summarise knowledge on plant exudates and mucilages within the concept of their functions in microenvironmental design, focusing in particular on their bioadhesive functions and the molecules responsible for them. We draw attention to areas of future knowledge need, including the microstructure of mucilages and their compositional and regulatory dynamics.